61.09 Timing and Frequency of Unplanned Readmissions after Heart Transplant Does Not Impact Long-term Survival

Posted on January 18, 2016

E. Lushaj1, T. Kohmoto1, L. Lozonschi1, S. Osaki1, A. Badami1, S. Ulschmidt1, S. Akhter1 1University Of Wisconsin,Cardiothoracic/Surgery,Madison, WI, USA

Introduction: Complications often occur long after heart transplantation (HT), requiring hospital readmission. Our goal was to identify the rate and etiology of unplanned readmissions following HT. We also analyzed the impact of unplanned readmissions on post-transplant survival.

Methods: We retrospectively reviewed 133 patients undergoing HT at our institution from 01/2004 to 05/2014. Six patients who expired during the index hospitalization were excluded from the analysis.

Results:Of the sample (n=127) 98 (77%) patients were readmitted 324 times (3.3 times/patient) as of end of follow-up. The median follow-up period was 56 (IQR: 21-105) months. Median time to first readmission was 59 (IQR: 10-185) days. Over half of readmissions (n=186; 57%) were within the first year post-discharge at index hospitalization. Of those, 52 (28%) were within 30 days post-discharge. Freedom from first readmission was observed for 66% of patients at 1 month, 51% at 3 months, 29% at 6 months and 18% at 12 months (Figure). Median hospital length of stay at readmission was 3 (IQR: 2, 6) days. Age, gender, BMI, previous LVAD support, surgery or CPB time at transplant, hospital and ICU length of stay were not risk factors for readmission. Readmission etiology included infections (23%), GI complications (15%), respiratory (14%), rejection (11%), cardiac (10%), renal (7%), cardiac allograft vasculopathy (2%). Readmissions due to infections included respiratory (32%), GI (22%), wound (16%), cytomegalovirus (5%). There was no significant difference in the long-term survival between readmitted and non-readmitted patients (Log-rank test: p=0.68).

Conclusion:The first year after discharge remains a high risk period for transplanted patients. Infections and GI complications were the leading causes of readmission. Readmissions did not negatively impact long-term survival of transplanted patients.

61.05 Mortality Difference in Malignant Pleural Effusions Treated with Pleural Catheter or Talc Pleurodesis

Posted on January 18, 2016

D. Liou1, D. Serna-Gallegos1, J. Chan1, J. Borgella1, H. J. Soukiasian1 1Cedars-Sinai Medical Center,Los Angeles, CA, USA

Introduction: Malignant pleural effusions (MPE) are commonly managed with either thoracoscopic placement of a tunneled pleural catheter (PC) for drainage or talc pleurodesis (TP). A variety of factors influence the decision regarding which treatment modality to pursue. Comparison of mortality associated with PC versus TP in patients with MPE has not been previously studied.

Methods: A retrospective review of our institutional lung cancer database was performed. Patients with metastatic cancer and MPE were analyzed. Demographic and clinical data were tabulated, including age, gender, site of primary cancer, method of MPE treatment, and mortality. Patients were grouped according to MPE treatment modality. Clinical variables were compared between the two treatment groups.

Results: A total of 766 patients with MPE treated by either PC or TP were included. 461 patients comprised the PC group and 305 the TP group. PC had a higher proportional of males compared to TP (49.7% vs. 38.0%, p<0.01). The predominant site of primary tumor in both groups was lung, followed by breast and gastrointestinal. PC had fewer primary lung (41.4% vs. 51.5%, p<0.01) and breast (12.1% vs. 19.3%, p<0.01) cancers compared to TP, but greater proportion of gastrointestinal (11.3% vs. 5.6%, p<0.01) and hepatobiliary (9.5% vs. 3.3%, p<0.01) tumors. 5-year survival was 12.5% in PC compared to 6.0% in TP (p<0.01).

Conclusion: Patients with metastatic cancer and MPE treated with PC had double the 5-year survival rate compared to patients treated with TP. Significant differences in gender and site of primary cancer were identified between the two treatment groups. Further research is warranted to investigate whether these factors contribute to the observed survival difference.

61.06 Clincal Significance Of Spontaneous Pneumomediastinum

Posted on January 18, 2016

B. A. Potz1, L. Chao1, T. T. Ng1, I. C. Okereke1 1Brown University,Surgery/Cardiothoracic Surgery/ Warren Alpert Medical School,Providence, RHODE ISLAND, USA

Introduction: Spontaneous pneumomediastinum (SPM) is classified as the presence of free air in the mediastinum in the absence of any precipitating cause. SPM is relatively uncommon, and the clinical significance and risk associated with SPM is not well understood and has not been widely documented in the literature. Our goals were to determine the outcomes of patients who presented with SPM and to determine predictors of severe pathology associated with SPM.

Methods: From 2004 through 2013, a retrospective review was conducted of all patients who were discovered to have SPM during presentation to our institution. Patient demographics, co-morbidities, laboratory values and presence of esophageal perforation were recorded.

Results: Over the 10 year span of the study 249 patients who presented to our institution were discovered to have spontaneous pneumomediastinum on chest x-ray or computerized tomography (CT) scan. Mean age was 38.7 years (1—93). Sixty-one percent (151/249) of patients were male. Subcutaneous emphysema was appreciated in 16 percent (39/249) of patients. Ten percent (24/249) of all patients were ultimately discovered to have esophageal perforation, determined by upper endoscopy, upper gastrointestinal series or intraoperatively during emergent surgery. Age (p <0.01), presence of pleural effusion (p < 0.01) and elevated white blood count (p < 0.01) were the only significant risk factors for presence of esophageal perforation (Table 1). Other variables, such as subcutaneous emphysema, elevated creatinine level and oxygen saturation were not associated with esophageal perforation.

Conclusions: SPM is usually associated with a benign clinical course. Risk factors for presence of esophageal perforation in these patients include age, elevated white blood count and presence of a pleural effusion. In the absence of abnormal laboratory values or associated radiologic findings, the majority of patients with SPM can be safely observed without the need for further diagnostic testing.

61.07 Direct Aortic Access for Transcatheter Aortic Valve Replacement is a Suitable Delivery Alternative

Posted on January 18, 2016

G. Savulionyte1, D. M. Strauss1, A. Das1, K. J. Oh1, N. L. Owen-Simon1, H. A. Cohen1, B. O’Murchu1, B. P. O’Neill1, G. Wheatley1 1Temple University,Cardiovascular Surgery,Philadelpha, PA, USA

Introduction: Transcatheter aortic valve replacement (TAVR) has become standard of care for high surgical-risk patients with severe, symptomatic aortic valve stenosis. However, these patients have a high associated incidence of peripheral vascular disease which can preclude delivery from a transfemoral (TF) approach. Alternative delivery options include transapical (TA) and trans-aortic (TAo). The purpose of this study was to compare the outcomes of TAVR procedures performed via a TAo approach versus a non-TAo approach.

Methods: A retrospective review of patients undergoing TAVR from December 2013 to June 2015 was performed. Institutional Review Board approval was obtained. Demographic information and outcome data were collected regarding type of vascular access, procedural success, and lengths of stay in the intensive care unit and hospital. Statistical analysis was performed using SPSS Statistics.

Results: Forty-two patients (10 TAo, 30 TF, 2 TA) underwent TAVR. Average age for TAo patients was 73.6 years and 80.3 years for non-TAo patients (p=0.11). M:F ratio was 1:9 for TAo patients, and 3:5 for non-TAo patients (p=0.10). Average Society of Thoracic Surgeons (STS) score for TAo patients was 11.8, and 8.5 for non-TAo patients (p=0.18). [Figure 1] Seven (70%) patients in the TAo group had a diagnosis of chronic obstructive pulmonary disease (COPD), and 16 (50%) patients in the non-TAo group had COPD (p=0.27). The Medtronic CoreValve was used in 4 patients undergoing TAo and 11 patients with non-TAo (p=0.75), while the Edward SAPIEN prosthesis was implanted in 6 patients receiving TAo and 21 patients in the non-TAo group. Procedural success was 100% in both groups. Operative times averaged 144.2 (99-203) minutes in the TAo group and 117.9 (60-207) minutes in the TF/TA group (p=0.048). Four TAo patients (40%) were extubated in the operating room, while 29 (90.6%) non-TAo patients were extubated in the operating room (p=0.00066). Average intensive care unit stay (ICU) was 4 (2-12) days for TAo patients and 2.35 (0-11) days for non-TAo patients (p=0.14). Average hospital stay for TAo patients was 10.2 (4-28) days and 4.9 (2-14) days for non-TAo patients (p=0.035). 30-day mortality was 10% (n=1) in TAo group and 3.1% (n=1) in the non-TAo group (p=0.37). 1-year mortality was 10% (n=1) in TAo group and 9.3% (n=3) in the TF/TA group (p=0.95).

Conclusion: TAo is a suitable alternative access point for TAVR patients unable to undergo a TF approach due to severe peripheral vascular disease. Although TAo patients have a longer length of hospital stay, the outcomes are comparable to non-TAo patients. Future studies are needed to assess the financial impact of this approach.

61.01 Effects of Diabetes and CPB on Adherens-Junction-Protein Expression of Human Peripheral Tissue

Posted on January 18, 2016

J. Feng1, A. K. Singh1, J. Liang1, Y. Liu1, F. W. Sellke1 1Brown University School Of Medicine,Cardiothoracic/Surgery,Providence, RI, USA

Introduction: Cardiac surgery with cardiopulmonary bypass (CPB) is often associated with the increased vascular permeability/tissue edema, microvascular endothelial cell injury/dysfunction. Especially, these disturbances are more pronounced in patients with poorly controlled diabetes. Recent study has demonstrated that the increased permeability after cardiopleogic arrest/CPB is associated with changes in the expression/phosphorylation of adherence-junction-proteins in the coronary vasculature in patients with type-2 diabetes (T2DM). We hypothesized that T2DM may be associated with altered adherence-junction-protein expression/phosphorylation of skeletal muscle/vessel in the setting of CPB . The aim of the current study was to investigate the changes in adherens-junction-proteins, such as VE-cadherin, and β-catenin of skeletal muscle and vessels in patients with or without T2DM in the setting of CPB and coronary artery bypass graft (CABG) surgery.

Methods: Chest wall skeletal muscle tissue was harvested pre- and post-CPB from the controlled diabetic (HbA1c: 6.3 ± 0.1), uncontrolled diabetic (HbA1c: 9.6 ± 0.3) and non-diabetic patients (HbA1c: 5.4 ± 0.1) undergoing CABG surgery (n = 6/group). The expression/phosphorylation of adherence-junction-proteins such as, VE-cadherin and β-catenin were assessed by immunoblotting and immuno-histochemistry. Skeletal-muscle-arteriolar endothelial function was assessed by videomicroscopy in response to the endothelium-dependent vasodilator substance P.

Results:There were no significant differences in basal protein expression of VE-cadherin between UDM and CDM or ND patients or between pre- and post-CPB among groups. The level of pre-CPB phosphorylated VE-cadherin tends to be 25% higher in the UDM group compared with ND (P = 0.03). CPB induced more phosphorylation of VE-cadherin (21% in ND; 30% in CDM and 43% vs. pre-CPB; P<0.05, respectively) and this effect was more pronounced in the UDM group (P<0.05 vs. ND or CDM). The post-CPB β-catenin was significantly decreased as compared with pre-CPB in all three groups (P<0.05) and the decrease was more pronounced in the UDM group (P<0.05). There were significantly decreases in vasodilatory response of skeletal muscle arterioles to substance P after CPB in all three groups (P<0.05). This alteration was more pronounced in the UDM patients (P<0.05).

Conclusion: These findings suggest that poorly controlled diabetes down-regulates endothelial adherence-junction-protein expression of skeletal muscle/vessel tissues in the setting of CPB. The enhanced tyrosine phosphorylation of VE-cadherin and degradation of β-catenin indicates deterioration of these proteins and the damage of the cell-cell endothelial junctions, specifically in the diabetic vessels. These alterations may lead to the increases in periphral vascular permeability and endothelial dysfunction and affect the outcomes in diabetic patients after CPB/cardiac surgery.

61.02 Is Local Anesthesia a Better Approach for Transcatheter Aortic Valve Replacement Procedures?

Posted on January 18, 2016

A. Das1, D. M. Strauss1, G. Savulionyte1, N. L. Owen-Simon1, K. J. Oh1, H. A. Cohen1, B. O’Murchu1, B. P. O’Neill1, G. Wheatley1 1Temple University,Cardiovascular Surgery,Philadelpha, PA, USA

Introduction: Optimal anesthetic strategy for transcatheter aortic valve replacement (TAVR) procedures has yet to be determined. Currently, general anesthesia (GA) is the accepted approach in those patients requiring transfemoral vascular access, however emerging data suggests that outcomes can be improved using local anesthesia (LA). The purpose of this study is to compare outcomes of patients with severe, symptomatic aortic valve stenosis undergoing transfemoral TAVR using general versus local anesthesia.

Methods: A retrospective review of patients undergoing TAVR from December 2013 to June 2015 was performed. Institutional Review Board approval was obtained. Demographic information and outcome data were collected regarding type of anesthesia, procedural success, respiratory complications and lengths of stay in the intensive care unit and hospital. Statistical analysis was performed using SPSS Statistics.

Results: A total of 30 patients (12 GA, 18 LA) underwent transfemoral TAVR. Average age for GA patients was 80.6 years and 81.3 years for LA patients (p=0.82). M:F ratio was 1:1 for GA patients, and 5:13 for LA patients (p=0.22). Average Society of Thoracic Surgeons (STS) score for GA patients was 9.6, and 7.8 for LA patients (p=0.30). [Figure 1] Five (41.7%) patients in the GA group had a diagnosis of chronic obstructive pulmonary disease (COPD), and 10 (55.6%) patients in the LA group had COPD (p=0.46). The Medtronic CoreValve was used in 2 patients undergoing GA and 9 patients with LA (p=0.06), while the Edward SAPIEN prosthesis was implanted in 10 patients receiving GA and 9 patients receiving LA. Procedural success was 100% in both groups. Operative times averaged 125.3 (88-207) minutes in the GA group and 109.6 (60-168) minutes in the LA group (p=0.13). No LA patient required conversion to GA. Ten GA patients (83.3%) were extubated in the operating room, while 1 (5.6%) LA patient required intubation on post-operative day 8 due to COPD exacerbation. Average intensive care unit stay (ICU) was 3.1 (1-8) days for GA patients and 2.4 (0-11) days for LA patients (p=0.32). Average hospital stay for GA patients was 6.9 (2-14) days and 5.5 (2-12) days for LA patients (p=0.36). 30-day mortality was 0 in GA group and 5.6% (n=1) in the LA group.

Conclusion: LA for transfemoral TAVR procedures is feasible and yields similar procedural outcomes as GA techniques. Although patients receiving LA had a higher incidence of COPD, fewer of these patients had post-operative respiratory complications and there were shorter ICU and hospital lengths of stay. Future studies will need to compare procedural and total hospital costs between these two anesthetic approaches.

61.03 Does Pre-operative Amiodarone Exposure Impact Outcomes in Cardiac Transplant Recipients?

Posted on January 18, 2016

E. Lushaj1, R. Dhingra2, S. Akhter1, T. Kohmoto1, S. Ulschmidt1, S. Osaki1, A. Badami1, L. Lozonschi1 1University Of Wisconsin,Cardiothoracic/Surgery,Madison, WI, USA 2University Of Wisconsin,Cardiovascular/Medicine,Madison, WI, USA

Introduction: Pre heart transplant (HTx) amiodarone use is very common. Concerns, however, still exist about increased complications related to use of amiodarone in the perioperative period.

Methods: Of all consecutive patients who received HTx at our institution between 1/2004 to 12/2014 (n=208), we compared the peri- and post-operative outcomes of 137 (66%) patients who were taking amiodarone (group 1) for at least 30 days before HTx to 71 (34%) patients not taking amiodarone (group 2).

Results:Age at transplant, BMI, gender, ischemic etiology, diabetes, hypertension status and donor ischemic time, were not different between the two groups (all p>0.05). Similar number of patients had implantable defibrillators prior to transplant (p=0.30). 72% of patients in group 1 and 48% in group 2 had a ventricular assist device prior to transplant (p=0.001). 51% of patients in group 1 and 37% in group 2 had COPD pre-HTx (p=0.058). Median operative time, aortic cross clamp time, intensive care unit time, prolonged ventilation and median hospital length of stay did not differ between groups (p>0.05). Higher cardiopulmonary bypass time was observed in group 1 (203 vs. 187 min; p=0.013). Patients in group 1 had more pneumonias (7% vs. 0%; p=0.024) and a tendency to develop post-transplant atrial fibrillation (7% vs. 1.4%; p=0.085). None of the patients was implanted with a permanent pacemaker. Patients in group 2 had a higher rejection rate (21% vs. 9%; p=0.017). Both groups had similar 30-day readmission and mortality rates (p>0.05). 1-year survival was not affected by use of amiodarone (p=0.98).

Conclusion:Our study showed that pre-operative amiodarone exposure did not protect from post-transplant atrial fibrillation and unexpectedly resulted in even a higher rate compared to control group. As previously reported lower rejection rates were found in patients exposed to pre-transplant amiodarone. Amiodarone use did not impact post-transplant short and long-term survival (p>0.05).

61.04 Late Durability of Decellularized Allografts for Aortic Valve Replacement: a Word of Caution

Posted on January 18, 2016

M. R. Helder1, N. T. Kouchoukos4, K. Zehr2, J. A. Dearani1, C. N. Heins3, H. V. Schaff1 1Mayo Clinic,Cardiovascular Surgery,Rochester, MN, USA 2Johns Hopkins University School Of Medicine,The John Hopkins Heart & Vascular Institute,Baltimore, MD, USA 3Mayo Clinic,Biomedical Statistics And Informatics,Rochester, MN, USA 4Missouri Baptist Medical Center,St. Louis, MO, USA

Introduction: Decellularized bioprostheses utilized for aortic valve replacement (AVR) have the theoretical advantage of reduced antigenicity and increased durability. Prior studies demonstrated satisfactory early outcome and negative panel reactive antibody in >90% of pt with DAVA 1 year postoperatively. However, long-term durability of DAVA is unknown.

Methods: We reviewed 42 consecutive pt who underwent AVR with a decellularized allograft from March 12, 2002 to October 6, 2004 at 2 institutions. We compared this cohort to 29 consecutive control pt who underwent AVR with a standard cryopreserved allograft during the same interval. The primary outcome was aortic valve reoperation, and secondary outcome was overall mortality.

Results:In pt undergoing AVR with DAVA, aortic reoperation was required in 37% (15/41) of survivors, and the most common indication was allograft regurgitation (7/15, 47%). In the 29 control pt receiving standard cryopreserved allografts, aortic valve reoperation was required in 17% (4/24), and aortic regurgitation was the indication in 2 (50%). Freedom from reoperation 5 yr postoperatively was 92% (95% CI, 84%-100%) in the DAVA group compared to 100% in the control group. Freedom from reoperation at 10 yr postoperatively was 51% (95% CI, 34%-76%) in pt receiving DAVA compared to 80% (95% CI, 60%-100%) in the control group (p=0.06). Overall 5 and 10-yr survival were 90% (95% CI, 80%-100%) and 76% (95% CI, 61%-93%) in the decellularized group compared the 72% (95% CI, 57%-90%) and 57% (95% CI, 38%-79%) in the control group (p=0.09).

Conclusion: Late survival of pt receiving DAVA was similar to that of pt with standard cryopreserved allografts. This study identified a strong trend for late allograft deterioration and reoperation beyond 5 yr postoperatively in the DAVA group. These findings should be considered when designing clinical trials of tissue-engineered bioprostheses.

06.19 Dialysis Status as a Predictor of Hemodialysis Access Failure: Do We Need to be More Proactive?

Posted on January 18, 2016

E. Benrashid1, L. M. Youngwirth1, J. Kim1, D. N. Ranney1, J. C. Otto1, J. F. Lucas2, J. H. Lawson1 1Duke University Medical Center,Division Of Vascular Surgery, Department Of Surgery,Durham, NC, USA 2Greenwood Leflore Hospital,Greenwood, MS, USA

Introduction:

Current guidelines encourage early hemodialysis (HD) access placement in the chronic kidney disease (CKD) and end stage renal disease (ESRD) population. A variety of patient and operative factors (i.e. preoperative target vein diameter) have been proposed as predictors for access success or failure, although the current literature is conflicting. The objective of this study was to determine whether there were any predictors for HD access failure in this population.

Methods:

The Society for Vascular Surgery Vascular Quality Initiative database was queried to identify all new HD access cases performed by a single surgeon from January 2011 – December 2013. The primary outcome of interest was access failure as defined at follow-up. Secondary outcomes included necessity for access revision via surgical or interventional (percutaneous) techniques. Multivariable logistic regression was used to determine factors associated with access failure and need for revision. Age, gender, race, smoking status, diabetes, BMI ≥ 30, presence of a central venous catheter, dialysis status, and access type were included in the model.

Results:

During the study period, 1,354 HD access cases were performed, with n = 1,238 (91.4%) of these autogenous arteriovenous fistulae (AVF), and the remainder prosthetic (n = 57; 4.2%) or biologic (n = 59, 4.4%) arteriovenous grafts (AVG). Overall mean age was 56.6 ± 14.3 years, black race was 77.0%, and male gender was 48.2%, which was not significantly different among the groups. The total proportion of patients actively on dialysis was 66.7%, which differed significantly amongst the three access types (p < 0.001). On multivariable logistic regression analysis, active dialysis status was associated with a significantly higher probability of access failure [adjusted odds ratio (AOR), (95% confidence interval [CI]): 1.91 (1.17, 3.11); p = 0.010]. Additionally, the presence of a biologic AVG was associated with a significantly higher probably for the need for access revision [AOR (95% CI): 2.26 (1.32, 3.86); p = 0.003].

Conclusions:

Active dialysis status is associated with a higher incidence of access failure, with biologic AVG in particular associated with a greater need for revision. This data suggests that patients with CKD who are ‘pre-dialysis,’ in which there is any suspicion for progression to ESRD requiring renal replacement therapy (RRT), should receive more aggressive surgical referral and proactive placement of AVF prior to initiating any form of RRT. Additionally, given the > 2X likelihood for reintervention, patients that receive biologic AVG may be better suited with other access modalities. However, this cohort in particular may have specific anatomical limitations or have expended other access options, which may preclude AVF creation or the use of more conventional synthetic graft materials.

06.20 Aspirin Use is Associated with Decreased Thrombus Sac Volume in Abdominal Aortic Aneurysms

Posted on January 18, 2016

L. E. Trakimas1, C. I. Aghaie1, D. S. Mix1, K. Rasheed1, J. L. Ellis1, R. J. Glocker1, A. J. Doyle1, M. C. Stoner1 1University Of Rochester,Vascular Surgery,Rochester, 14642, USA

Introduction: Data suggest that pro-inflammatory mediators play a key role in the formation and enlargement of abdominal aortic aneurysms (AAA). Formation and renewal of intramural thrombus is also associated with inflammation, and is known to contribute to the complexity of aneurysm repair. Current cardiovascular pharmacotherapy includes a number of inflammatory modulators such as aspirin (ASA), Plavix (clopidogrel), statins, and angiotensin-converting enzyme inhibitors (ACE-I). The purpose of our study was to investigate the effect of these inflammatory modulators on radiographically-determined thrombus sac volume (TSV).

Methods: Patients who underwent elective infrarenal aortic repair were identified. Pre-operative CT scans were reviewed, and TSV was obtained using a Hounsfield Unit (HU) restricted region growth algorithm. Receiver-operator characteristic curves were systematically generated for TSV and various cardiovascular pharmacotherapies. Additional co-morbid conditions such as diabetes mellitus (DM) and post-operative complications were also evaluated versus TSV.

Results: A total of 210 patients (mean age = 72.0, SE 0.63 years; mean TSV = 81.9, SE 5.83 cm3) were identified. ASA use was associated with a decreased thrombus sac volume ≤ 50 cc (AUC = 0.616, p= 0.013) (figure) whereas statins (p= 0.258), ACE-I (p= 0.455), and Plavix (p= 0.622) had no correlation to thrombus sac volume. DM was not associated with TSV (p= 0.311). Post-operative bleeding was also not associated with TSV (p = 0.120).

Conclusion: ASA use is associated with decreased TSV in a patient population undergoing elective AAA repair. The effect of ASA over other anti-inflammatory and anti-platelet agents is possibly attributable to its distinct mechanism of cyclooxygenase-1 (COX-1) inhibition. These data suggesting a key role of COX-1 in aneurysm thrombus modulation. DM, a known correlate of aneurysm incidence, is not related to thrombus burden. The potential to alter aneurysm thrombus volume affecting aneurysm morphology may yield a more favorable aneurysmal repair.

06.16 The Effect Of Use And Timing Of Venous Thromboembolism Chemoprophylaxis After Major Vascular Surgery.

Posted on January 18, 2016

D. C. Horne1, P. Georgoff1, M. A. Healy1, N. H. Osborne1 1University Of Michigan,Department Of Surgery,Ann Arbor, MI, USA

Introduction:

Venous thromboembolism (VTE) has been reported to occur in as much as 2-33% of patients undergoing major open vascular surgery. Despite this relatively high incidence, patients inconsistently receive chemoprophylaxis. The true incidence of VTE among patients receiving chemoprophylaxis is unknown. We sought to explore the effect of not only administration, but timing of administration of chemoprophylaxis on risk of VTE and post-operative bleeding among patients undergoing major open vascular surgery.

Methods:

Patients undergoing major open vascular surgery (defined as open abdominal aortic aneurysm repair, aorto-femoral bypass, mesenteric bypass) and infrainguinal bypass were identified from the Michigan Surgical Quality Collaborative (MSQC) between 2008 and 2012. Rates of VTE (deep venous thrombosis and/or pulmonary embolism) were compared between patients receiving and not receiving routine VTE chemoprophylaxis using univariate and multivariate statistics. Delay in the initiation of chemoprophylaxis was defined as initiation of therapy greater than 1 day following surgery. Among patients receiving VTE chemoprophylaxis, the effect of the timing of initiation of chemoprophylaxis upon development of VTE was determined using multivariate statistics. Post-operative complications were compared among all groups using univariate and multivariate analysis.

Results:

A total of 8776 patients underwent major open vascular surgery, including 1068 open AAA repairs, 958 aorto-femoral bypass and 6483 infrainguinal bypass procedures. The overall incidence of 30-day VTE was 1.4%, ranging from 0.99% among patients undergoing infrainguinal bypass and 2.62% among patients undergoing open abdominal procedures. Among all patients who received VTE chemoprophylaxis anytime during their admission, the rate of VTE was 1.45% as compared to 1.38% among those who did not receive chemoprophylaxis. However, accounting for the timing of chemoprophylaxis initiation, delay in the administration of VTE chemoprophylaxis was associated with a significantly higher risk of VTE (OR 3.92, p<0.01), controlling for pre-op risk of VTE. There was no increased risk of post-operative transfusion among patients receiving routine chemoprophylaxis compared those who did not (16.28% vs. 17.43%, p=0.197).

Conclusions:

Although patients undergoing major open vascular surgery appear to have a low risk of VTE at baseline, there is a significantly higher risk of developing VTE among patients who have a delay in the administration of VTE chemoprophylaxis. Bleeding complications were no higher among patients who routinely receive chemoprophylaxis. Surgeons should consider routinely initiating chemoprophylaxis in the early post-operative setting following major open vascular surgery.

06.17 Temporal Variability of Mortality & Readmission Determinants in Peripheral Vascular Surgery Patients

Posted on January 18, 2016

M. J. Lin1, F. Baky2, B. Housley2, N. Kelly2, M. Chowdhury2, D. B. Tulman2, E. Pletcher1, J. D. Balshi1, S. P. Stawicki1, D. C. Evans2 1St. Luke’s University Health Network,Department Of Surgery,Bethlehem, PA, USA 2Ohio State University,Department Of Surgery,Columbus, OH, USA

Introduction: Vascular surgery patients constitute a population subset that has traditionally been considered "high-risk" for readmissions and mortality. Although various studies report factors associated with readmission or mortality in this population, data continue to be limited regarding the temporal risk profile for readmissions and mortality during the initial postoperative year. We set out to determine the relationship between various clinical determinants, hospital readmissions, and mortality in a sample of vascular surgical patients. We hypothesized that factors independently associated with hospital readmission and mortality will gravitate from traditional "short-term" indicators toward the more established "long-term" outcome determinants at 90, 180, and 360-day postoperative cut-off points.

Methods: Medical records of peripheral vascular surgery patients at two institutions (2008-2014) were retrospectively reviewed. Abstracted data included demographics, procedural characteristics, the American Society of Anesthesiologists (ASA) Physical Status, Goldman Criteria for postoperative cardiac complications, Charlson Comorbidity Index, morbidity, readmission data (30-day, 180-day, 360-day), and mortality (30-day, 180-day, 360-day). Univariate analyses were performed for both readmissions and mortality at each specified time point. Variables reaching statistical significance of p<0.20 were included in subsequent multivariate analyses for factors independently associated with readmission/mortality.

Results: A total of 450 patients were included in the current analysis. Most patients underwent either a bypass or endarterectomy revascularization (406/450) or non-catheter dialysis access procedure (44/450). There were 188 males and 262 females (mean age 61.1±13.8, 14% emergent procedures, median operative time 177 minutes). Median hospital length of stay (index admission) was 4 days (25%-75% IQR 2-8 days). Cumulative readmission rates at 30, 180, and 360 days were 12%, 27%, and 35%. For mortality, the corresponding figures were 3%, 7%, and 9%, respectively. Table 1 shows factors independently associated with 30-day, 180-day, and 360-day readmissions and mortality.

Conclusion: We noted important patterns in temporal variability regarding the risk of hospital readmission and mortality in peripheral vascular surgery patients. Previous readmissions, frailty/acuity indices, and cardiovascular morbidity were all independently associated with subsequent risk of readmission and mortality. The knowledge of temporal trends described herein may be helpful in guiding readmission reduction approaches — a consideration of increasing importance in the evolving paradigm of value-based healthcare.

06.18 A Time Based Risk Model To Screen Post EVAR Patients

Posted on January 18, 2016

C. M. Png1, R. O. Tadros1, P. L. Faries1, S. Kim1, W. Beckerman1, M. R. Torres1, Z. M. Feldman1, M. L. Marin1 1Mount Sinai School Of Medicine,New York, NY, USA

Introduction: Follow up computed tomography angiography (CTA) scans add considerable post implantation costs to endovascular aneurysm repairs (EVAR) of abdominal aortic aneurysms (AAA). By building a risk model, we hope to identify patients at low risk for postoperative complications in order to minimize unnecessary CT scans.

Methods: 557 consecutive patients were reviewed. Probit models were created for four outcomes: aneurysm sac enlargement, reintervention, type I/III endoleaks and type II endoleaks, using preoperative aneurysm morphology, patient demographics and operative details as covariates. Patients with an abnormal 30 day post operative CT scan were excluded. Time points chosen for analysis were 1-year, 2-year, 3-years and 10-year post EVAR. A combined model including three outcomes was also created.

Results: Individual models that showed most significance were aneurysm sac enlargement at 1-year post EVAR (n=411; Sensitivity=1; Specificity=0.47; Accuracy 0.48) and reintervention at 2-year post EVAR (n=494; Sensitivity=1; Specificity=0.42; Accuracy=0.45). Notably, our models reported that increasing iliac artery diameter and increasing aortic neck angle increased the risk for a reintervention, while increasing iliac artery tortuosity increased the risk for a type I/III endoleak. Similarly, almost all statistically significant covariates were qualitatively supported by prior literature. Our final combined model would prevent the need for post-EVAR CTA in 59 patients (16%) at 1 year, 26 (7%) patients at 2 years and 6 (2%) patients at 3 years with 100% sensitivity. (Table 1)

Conclusion: Our model is a robust predictor of patients at low risk for post AAA EVAR complications. With additional validation and refinement, it could be applied to practices to cut down on the overall need for post-implantation CTA. Reducing the number of CT scans will reduce post-implantation cost and radiation exposure.

06.14 Predictors Of 30-Day Post-Operative Outcomes Following Carotid Revascularization Procedures

Posted on January 18, 2016

B. J. Nejim1, I. Arhuidese1, C. Hicks1, T. Obeid1, S. Wang1, J. Canner1, M. Malas1 1Johns Hopkins University School Of Medicine,Surgery,Baltimore, MD, USA

Introduction: The aim of our study is to compare the postoperative outcomes of Carotid Endarterectomy (CEA) with Carotid Artery Stenting (CAS) using the Procedure-targeted American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database.

Methods: Patients who underwent CEA or CAS were identified in ACS-NSQIP for the years 2011 – 2013. Mean difference estimates and chi-square tests were used as appropriate. Univariate and multivariate logistic regression analysis were performed to evaluate the predictors of post-operative outcomes (any stroke or death and myocardial infarction (MI)) adjusting for age, gender, comorbidities, symptomatology, degree of stenosis and emergency surgical status.

Results: Of the 10,169 patients who underwent carotid revascularization, 9,817 (96.5%) underwent CEA while 352 (3.5%) underwent CAS during the study period. Sixty one percent of the cohort were males. Patients who underwent CEA were older than those undergoing CAS [mean age (SD): 71.3 (9.4) vs. 69.1 (9.7) years, p <0.001]. However, patients who underwent CAS had a greater prevalence of diabetes (38.4% vs. 29.2%, p<0.001), hypertension (88.1% vs. 84.9%, p=0.104), congestive heart failure (4.8% vs. 1.4%, p<0.001) and COPD (17.3% vs. 10.2%, p<0.001). The risk of post-operative stroke/death was 92% higher with CAS (Adjusted odds ratio: 1.92; 95% Confidence Interval: 1.04-3.52), receiving blood transfusion 72 hours prior to surgery was associated with 5-fold increase of mortality odds (aOR: 5.47; 95%CI: 1.79-16.73), other significant predictors of stroke/death were symptomatic status (aOR: 1.60 ,95%CI:1.19-2.16) and emergency surgery status (aOR: 2.35 ,95%CI: 1.31-4.23). No significant association was found between the type of procedure and odds of unplanned reoperation (aOR: 0.60; 95%CI: 0.22-1.63). Thirty-day post-op myocardial infarction was mostly related to patient’s age and being on hypertension medication whereas the type of procedure was found not to be significantly associated with post-op MI (aOR: 0.84; 95%CI: 0.26-2.67). Although readmission odds was higher for CAS, this association was not significant (aOR: 1.23; 95%CI: 0.82-1.85)

Conclusion: Carotid stenting is associated with higher odds of both post-operative mortality and stroke. The adverse impact of pre-procedural blood transfusion on outcomes is a call for caution and deserves further elucidation. Carotid procedure type is not a predictor of post-op MI or readmission, suggesting that these outcomes are a function of other patient factors. Further studies are warranted to evaluate the ability of the administrative dataset models to predict postoperative outcomes following carotid revascularization.

06.15 A 30 Year Experience with Tibial/Peroneal Arterial Revascularization using Polytetrafluoroethylene.

Posted on January 18, 2016

N. J. Gargiulo1, F. J. Veith3, E. C. Lipsitz4, N. S. Cayne3, G. S. Landis2 1The Brookdale Hospital And Medical Center,Vascular Surgery,New York, NY, USA 2Northwell Health System,New Hyde Park, NY, USA 3New York University,Surgery,New York, NY, USA 4Montefiore Medical Center,Surgery,Bronx, NY, USA

Introduction: Polytetrafluoroethylene (PTFE) tibial and peroneal arterial bypasses without vein cuffs, patches or arteriovenous fistulas have been advocated for critical limb ischemia in circumstances when autologous saphenous vein is not available. This reviews a 30-year experience.

Methods: A retrospective analysis was performed on a group of 377 patients with critical limb ischemia facing immediate amputation requiring revascularization between July 1977 and June 2011. These 377 patients had no autologous vein on duplex examination and operative exploration and underwent 411 PTFE bypasses to a tibial or peroneal artery (the only patent outflow vessels) without any adjunctive procedure. The majority of these patients had two or more prior ipsilateral infrainguinal bypasses. Tourniquet control of the tibial or peroneal was used in the majority of cases (85%). Cumulative life table primary and secondary patency and limb salvage rates were calculated for these bypasses. These results were compared to those infrapopliteal bypasses performed with alternate autologous vein conduits or PTFE in conjunction with an adjunctive procedure (i.e. cuff, patch or av fistula).

Results: The 5- and 10-year cumulative primary graft patency rates for tibial and peroneal arterial PTFE bypasses were 39% +/- and 28% +/-, respectively. Secondary graft patency rates were 55% and 51% at 5 and 10 years, respectively. Limb salvage rates were 71 % at 5 years and 66% at 10 years. Several effective surgical strategies employed over the last 3 decades included meticulous attention to the distal anastomosis, mandatory completion arteriography, initial pharmacologic treatment of distal anastomotic or runoff pseudodefects, thrombectomy and/or graft extension for those defects that failed to resolve, and postoperative anticoagulation.

Conclusions: PTFE bypasses without adjunctive procedures to infrapopliteal arteries is an acceptable alternative option for those patients without autologous vein facing imminent amputation in this small cohort of patients. Several important perioperative strategies may help improve PTFE graft patency and overall limb salvage.

06.11 Gender Differences in Mortality Following Ischemia-Reperfusion Injury in Diabetic Animals

Posted on January 18, 2016

N. N. Rizk1, E. Abbott1, M. Rizk2, A. Fischer1,2, J. Dunbar2 1Beaumont Health System Research Institute,General Surgery,Royal Oak, MI, USA 2Wayne State University,Physiology,Detroit, MI, USA

Introduction: The physiologic differences between men and women are well characterized so their clinical manifestations in pathologic states should potentially exhibit differences. Much of preclinical research utilizes male animal models to develop treatment modalities for clinical applications assumed to extrapolate to both genders. In this study we evaluated normal and diabetic female rats response to stroke and reperfusion injury and compared to our previously characterized outcomes in male rats.

Methods: We utilized middle cerebral artery occlusion (MCAO) and reperfusion model in normal and diabetic Wistar female animals. Following 24-hour MCAO and 2-hour MCAO followed by 24-hour reperfusion interval, several CNS parameters were examined, lesion volume (Triphenyltetrazolium Chloride), up regulation of apoptosis [TUNEL immunoreactivity in the sensori-motor cortex (layers-5 and 6) and the hippocampal pyramidal cell layers (CA1 and CA3 sectors)], as well as the percent survival.

Results: The two parameters in which the female animals differed significantly from their male counter parts were i) in lesion volume following restoration of blood flow with 2-hour MCAO and ii) in mortality following 24-hour MCAO and in following restoration of blood flow with 2-hour MCAO. Restoration of blood flow following 2-hour MCAO significantly decreased lesion volume in the normal and diabetic female animals (13.95 ± 8.16* and 20.32 ± 6.85*, respectively). In comparison to the male counterparts, lesion volumes following reperfusion were significantly less for normal male rats and significantly more for the diabetic male animals (3.8 ± 2.36# and 31.25 ± 2.5#, respectively). Twenty-hour MCAO and restoration of blood flow with 2-hour MCAO proved to be significantly more detrimental to the female animals with lower survival (normal 65%, diabetic 55% survival, p<0.05) in comparison to the male animals (normal 90%, diabetic 65% survival, p<0.05). There was a significant increase in TUNEL immunoreactive cells in the diabetic animals following reperfusion injury compared with the control counterpart. There were no appreciable differences in TUNEL immunoreactivity between male and female diabetic animals following reperfusion.

Conclusion:This paper highlights the dramatically different outcomes and metrics in different genders in animal models. Thus one gender alone may not translate into clinically relevant data applicable to both genders. We have demonstrated that both male and female diabetic animals have an exaggerated response to stroke and to restoration of blood flow but differ in their outcome with a significantly more detrimental outcome for the female sex. Understanding the exaggerated vascular response to injury in the female animal model is important in developing gender specific treatment modalities.

06.12 Non-Platelet Length Polyphosphates Inhibits tPA Mediated Fibrinolysis

Posted on January 18, 2016

P. J. Lawson1,2, H. B. Moore1,2, A. W. Bacon1,2, E. Gonzalez1,2, A. P. Morton1,2, A. Banerjee1, J. H. Morrissey3, E. E. Moore1,2 1University Of Colorado Denver,Surgery,Aurora, CO, USA 2Denver Health Medical Center,Surgery,Denver, CO, USA 3University Of Illinois,Surgery,Urbana, IL, USA

Introduction:
Fibrinolysis shutdown is the dominant phenotype in severely injured patients, but the mechanisms driving post-injury tPA resistance remain unknown. Polyphosphates are ubiquitous inorganic compounds that have recently been linked to coagulation. Polyphosphates are stored in platelets, and platelets are known to inhibit fibrinolysis. We hypothesize that polyphosphate polymers that are similar in size to the length of chains stored in platelets will inhibit tPA mediated fibrinolysis.

Methods:
Polyphosphates of four different polymer lengths were evaluated. Monophosphate, platelet length polyphosphates, medium size polyphosphates found in tissue, and large polyphosphates of the size produced by microbes. Polymers of different sizes were added at a concentration of 20 micromolar in whole blood from eight healthy volunteers and assessed with thrombelastography (TEG) for changes in clotting parameters with and without tissue plasminogen activator (tPA) to quantify inhibition in fibrinolytic activity.

Results:
Large polyphosphates reduced R time and increased angle in the presence of tPA compared control blood (p<0.001, p=0.008) and trended towards an increase in clot strength (MA p=0.052). Large, medium, and mono polyphosphates reduced LY30 compared to control (p=0.034, Figure 1). The other polymer lengths in the presence of tPA did not significantly alter other clotting parameters. Without tPA, the same relationship of shortened clotting time and increased angle were appreciated with the large polyphosphates (p<0.001, p=0.015). None of the other polymer lengths affected clot parameters.

Conclusion:
Large chain polyphosphates are associated with a rapid forming strong clot. Polyphosphates polymers in the length stored in platelets, however, did not impact clotting parameters. But all other polymer lengths inhibited tPA mediated fibrinolysis. These experiments indicate that platelet derived polyphosphates are either modified after release from stored granules, or the polyphosphates regulating coagulation are from another source.

06.13 High Glucose Does Not Inhibit Aortic Endothelial Cell Sprouting and Stimulates Proliferation

Posted on January 18, 2016

A. D. Morris1, H. Li1, K. Kuo1, S. Dalal1, L. P. Brewster1,2 1Emory University School Of Medicine,Division Of Vascular Surgery,Atlanta, GA, USA 2Atlanta VA Medical Center,Division of Vascular Surgery,Atlanta, GA, USA

Introduction:
Diabetes increases the risk of cardiovascular disease and major amputation, but the aggressive control of blood sugar levels in recent clinical trials did not correspond to better clinical outcomes. Endothelial cell regeneration is critical to preventing thrombotic and myointimal complications after vascular injuries and interventions, but the impact of hyperglycemia on this process is not well understood. Since hyperglycemia directly inhibits cellular homeostasis, we propose that it negatively impacts endothelial cell regeneration.

Methods:

Proliferation Protocol:

Human aortic endothelial cells(HAEC) were grown in standard culture conditions, and then plated in a 96-well plate at 5000 cells per well. After reaching ~70% confluence, the cells were quiesced with serum starvation for 24 hours. The cells were restimulated with growth media (positive control) or quiescent media (negative control) with 40mM glucose or 40mM mannose (oncotic control) added to both groups. After 72 hours, HAEC proliferation was collected by commercially available cell viability assay using absorbance.

3D Angiogenesis Assay:

HAECs were formed into pellets (40,000 cells) using mechanical rotation. The pellets were suspended in a fibrin hydrogel. The cell pellets were exposed to either 40mM glucose in growth media, 40mM mannose in growth media, or growth media for 3 days. HAEC invasion was captured by daily microscopy and analyzed as average sprout length at 10-degree intervals through 360 degrees by Matlab programming.

Results:

Contrary to our hypothesis, HAECs had greater proliferation in a 72-hour high glucose and high mannose environment compared to normal growth media (p<0.0001, p=0.030). Glucose media had additional proliferation potential compared to mannose media (p=0.012). High glucose and mannose conditions did not inhibit HAEC sprout length at any time point in the 3D angiogenesis assay.

Conclusion:

While there is literature supporting an inhibitory effect of high glucose on endothelial cells, it is related to a combination of concentration and time of exposure to high glucose conditions. In this work, we are surprised to find not only a lack of inhibition of EC sprout formation, but also an increase in EC proliferation with both high glucose and high mannose conditions. Perhaps, the 24 hours of quiescence positively affects proliferation in functionally starving cells. We are actively testing this by including the high glucose levels from the beginning of the experiment. The lack of inhibition on EC sprouting suggests that acute hyperglycemia may not inhibit EC angiogenic activity in a meaningful manner. The duration and severity of hyperglycemia that must be avoided remains a clinically important idea that must be further pursued.

06.09 Leukadherins: A Novel Agonist Approach To Treat Atherosclerosis Via Mac-1 Activation

Posted on January 18, 2016

A. Mesa1, S. Rahimpour2, N. Fernandez1, L. Song1, S. M. Pham2, K. A. Webster1, V. Gupta3, R. I. Vazquez-Padron1 1University Of Miami,Miami, FL, USA 2University Of Maryland,Baltimore, MD, USA 3Rush University Medical Center,Chicago, IL, USA

Introduction:
Atherosclerosis is a chronic systemic disease characterized by the accumulation of lipids and leukocytes in the arterial intima which eventually lead to myocardial infarction and other detrimental vascular events. New investigations revealed the role of integrin Mac-1 in leukocyte adhesion, migration and recruitment during the development of vascular proliferative diseases.

Methods:
In this study, a novel Mac-1 agonist drug named leukadherins (LA-1) is used as an innovative therapeutic tool to control inflammation with the ultimate goal to diminish atherogenesis. To test our hypothesis, daily intraperitoneal LA-1 or vehicle (control) injections (10 mg/ml) were administered to 20 hypercholesterolemic mice (ApoE null mice) kept in high fat diet for 16 weeks.

Results:
Mice treated with LA-1 exhibited a significantly reduction of monocytes and pro-inflammatory molecules in blood (p ≤ 0.001). Assessment of aortic atherosclerosis burden of treated and control mice indicated that LA-1 treatment significantly decreased atherosclerotic development (p = 0.03). Additionally, the results suggested that LA-1 reduces inflammation by retaining monocytes in bone marrow and spleen given that treated mice showed a significant reclusion of monocytes in these primary hematopoietic organs (p ≤ 0.001).

Conclusion:
These results suggest LA-1 treatment via Mac-1 activation represents a novel agonist approach for treating vascular inflammation and atherosclerosis.

06.10 Radiographic Kidney Volume Perfusion Correlates with Aortic Anatomic Severity Grade

Posted on January 18, 2016

C. I. Aghaie1, L. E. Trakimas1, D. S. Mix1, K. Rasheed1, M. Seaman1, J. L. Ellis1, R. J. Glocker1, A. J. Doyle1, M. C. Stoner1 1University Of Rochester,Vascular Surgery,Rochester, NY, USA

Introduction:
Anatomic Severity Grade (ASG) represents a quantitative mechanism for assessing anatomical suitability for endovascular aortic repair. ASG has been correlated with perioperative and mid-term outcomes, and resource utilization. The purpose of this study was to identify the correlation of a novel renal perfusion metric and ASG.

Methods:
Elective infrarenal aortic repair cases were identified in a retrospective database, describing patient operative and anatomical factors. Anatomic grading was undertaken by independent reviewers. Using volumetric software, kidney volume and a novel measure of kidney functional volume – radiographic kidney volume perfusion (RKVP) – was recorded. Systematic evaluation of the relationship of kidney volume and RKVP to CKD (glomerular filtration rate (GFR) < 60 ml/min) and ASG was undertaken using linear regression and receiver-operator statistical tools.

Results:
A total of 386 cases with patient and anatomic data were identified and graded. Mean age was 72.9 ± 0.4 years. Renal volume < 281 mL was correlated with CKD (AUC = 0.708, p = <0.0001). RKVP < 22.5 HU*L was correlated with CKD (AUC = 0.764, p = <0.0001). High (≥15) ASG scores correlated with both renal volume (AUC = 0.628, p = < 0.0001) and RKVP (AUC = 0.628, p = < 0.0001). Regression analysis demonstrated a strong, inverse relationship between ASG and RKVP (Figure).

Conclusion:
These data demonstrate that the novel metric of RKVP correlates with both CKD and ASG in a large database of patients undergoing elective aneurysm repair. The inverse relationship between renal function (renal volume, RKVP or GFR) and ASG has not been described in the literature before. Outcomes in patients with poor renal function may be related to anatomical issues in addition to well-described systemic ramifications.

« Previous Page
Next Page »