A. M. Flores1, M. Fakhari1, J. Darling1, M. L. Schermerhorn1,2, R. J. Guzman1,2 1Beth Israel Deaconess Medical Center,Vascular Surgery,Boston, MA, USA 2Harvard School Of Medicine,Boston, MA, USA
Introduction: In patients with chronic limb-threatening ischemia (CLI), assessment of pedal perfusion is often complicated by non-compressible ankle arteries resulting in false elevation of the ankle-brachial index (ABI). When the ABI cannot be calculated, toe pressures are often used as a surrogate measure. However, the utility of toe pressure measurements has been questioned. We thus sought to investigate the variability of pre-operative toe pressures, whether they correlated with preoperative cardiovascular risk factors, and if they predicted long-term outcomes in patients with CLI.
Methods: Consecutive patients presenting with signs and symptoms of CLI between 2010 and 2015 were identified by review of the institutional electronic medical record. All patients who underwent pre-operative vascular lab assessment by arterial Doppler with toe pressure measurements were then used for the present study. Demographic and cardiovascular risk factors were recorded as well as results from pre-operative, non-invasive arterial studies performed within 1 month of a procedure on the index limb. Extent of occlusive disease was assessed by determining TASC classifications for the femoral-popliteal and tibial levels on pre-operative imaging studies. A composite TASC score of the index limb was derived by adding the two values. The index limb, interventions, and outcomes including amputation and survival were identified by review of the medical record. Toe pressures from the index limb were used for all statistical analyses.
Results: We identified 124 patients that met inclusion criteria. Of these, 83% had diabetes, 54% had a history of tobacco use, and 21% had a history of renal failure requiring dialysis. Symptoms of ischemic rest pain were present in 15%, ulcers in 68%, and gangrene in 17% of patients. The mean (standard deviation) for toe pressure measurements was 32 (29.5). The median (range) was 29 mm Hg (0-119). Of the 124 index limb toe pressures, 21 (17%) were over 60, 10 (8%) were over 80 mm Hg, and one patient had non-compressible toe vessels. There was no correlation identified between toe pressures and age or cardiovascular risk factors; however, toe pressures were lower in patients on hemodialysis (p=0.023), and in those with higher TASC scores (p=0.003). In outcomes analyses, pre-operative toe pressures did not predict major amputation or 3-year survival.
Conclusion: In a small cohort of patients with CLI, pre-operative toe pressures demonstrated significant variability and did not correlate with demographic or cardiovascular risk factors, but they were lower in patients with renal failure and those with more extensive occlusive disease. They did not predict amputation or long-term survival.