L. Gonzalez1,2, M. Kassem1,2, A. Owora3, S. Cardounell1, M. Monita1, S. Brangman1, V. Gahtan1,2 1State University Of New York Upstate Medical University,Vascular And Endovascular Surgery,Syracuse, NY, USA 2Syracuse VA Medical Center,Surgery,Syracuse, NY, USA 3Syracuse University,Falk College School Of Public Health,Syracuse, NY, USA
Introduction: Frailty severity is a predictor of poor outcome after vascular surgery. The modified frailty index (mFI) has been validated as a prognostic assessment tool in large scale databases of patients with peripheral arterial disease. Our objectives were to determine the predictive utility of the mFI after first-time lower extremity revascularization and to identify biomarkers of frailty in patients with peripheral arterial disease. Hypotheses: (1) frailty severity is associated with adverse outcome after revascularization and (2) select preoperative data may serve as biomarkers of frailty.
Methods: A retrospective cohort study was performed of all first-time revascularizations [open surgery (OS) and endovascular surgery (ES)] in male veterans at a single institution (2003-2016). Multivariable logistic and Cox proportional hazard regression models were used to examine the relationship between the mFI and post-operative short-term (30-day morbidity, readmission, and re-intervention) and long-term (up to 2-year incidence of re-intervention, amputation, or mortality) outcomes, respectively.
Results: 431 patients met inclusion criteria (OS n=188; ES n=243), with a mean age of 66±9 years and median follow up of 16 months. Treatment groups were similar in baseline characteristics, pre-operative lab values, and polypharmacy tallies. Mean mFI was 0.39±0.16 for the OS group and0.38±0.15 for the ES group (p=0.43). 30-day complications (aOR 4.89; 95%CI: 1.67-14.33) and early readmissions (aHR 3.32; 95%CI: 1.16-9.55) were increased in the OS group compared to the ES group. Frailty severity did not predict risk of re-intervention in either group. Kaplan Meier analysis showed an increased risk of amputation, death, and the composite outcome of amputation and/or death in both treatment groups with increasing frailty when stratified by frailty severity (p<0.005 for all). Multivariate analysis confirms that frailty independently predicts major amputation (aHR 2.16; 1.06-4.39), mortality (aHR 2.62; 95%CI: 1.17-5.88), and the composite outcome (aHR 1.97; 95%CI: 1.06-3.68) in the cohort as a whole. Hypoalbuminemia is correlated with increased mFI in the ES group (p<0.01), but only showed a trend with mFI in the OS group (p>0.05). Independent of treatment assignment and preoperative mFI, higher albumin concentration was associated with lower risk of amputation (aHR: 0.58; 95% CI: 0.36 -0.94) and mortality (aHR: 0.45; 95% CI: 0.25-0.83). Higher hemoglobin concentration was also independently predictive of limb salvage (aHR 0.72 95%CI: 0.62-0.84).
Conclusion: Frailty severity is predictive of short- and long-term outcomes after lower extremity revascularization. Hypoalbuminemia and anemia are associated with higher mFI and independently predicted poor outcome after revascularization, suggesting albumin and hemoglobin concentration may serve as true biomarkers of frailty in this population.