Ankle‐brachial index to monitor limb perfusion in patients with femoral venoarterial extracorporeal membrane oxygenation

Abstract

Background Limb ischemia is a major complication of femoral venoarterial extracorporeal membrane oxygenation (VA‐ECMO). Use of ankle‐brachial index (ABI) to monitor limb perfusion in VA‐ECMO has not been described. We report our experience monitoring femoral VA‐ECMO patients with serial ABI and the relationships between ABI and near infrared spectroscopy (NIRS). Methods This is a retrospective single‐center review of consecutive adult patients placed on femoral VA‐ECMO between January 2019 and October 2019. Data were collected on patients with paired ABI and NIRS values. Relationships between NIRS and ABI of the cannulated (E‐NIRS and E‐ABI) and non‐cannulated legs (N‐NIRS and N‐ABI) along with the difference between legs (d‐NIRS and d‐ABI) were determined using Pearson correlation. Results Overall, 22 patients (mean age 56.5 ± 14.0 years, 72.7% male) were assessed with 295 E‐ABI and E‐NIRS measurements, and 273 N‐ABI and N‐NIRS measurements. Mean duration of ECMO support was 129.8 ± 78.3 h. ECMO‐mortality was 13.6% and in‐hospital mortality was 45.5%. N‐ABI and N‐NIRS were significantly higher than their ECMO counterparts (ABI mean difference 0.16, 95% confidence interval [CI]: 0.13–0.19, p < .0001; NIRS mean difference 2.51, 95% CI: 1.48–3.54, p < .0001). There was no correlation between E‐ABI versus E‐NIRS (r = .032, p = .59), N‐ABI versus N‐NIRS (r = .097, p = .11), or d‐NIRS versus d‐ABI (r = .11, p = .069). Conclusion ABI is a quantitative metric that may be used to monitor limb perfusion and supplement clinical exams to identify limb ischemia in femorally cannulated VA‐ECMO patients. More studies are needed to characterize the significance of ABI in femoral VA‐ECMO and its value in identifying limb ischemia in this patient population.

Vascular Access Management in Complex Percutaneous Coronary Interventions

“…28,29 Alternatively, the use of ankle-brachial index (ABI) in extracorporeal membrane oxygenation (ECMO) patients undergoing continuous NIRS monitoring has been described; ABI decreases of 0.10-0.15 were associated with acute limb ischemia without concomitant changes in NIRS values, but this was not statistically significant. 30 Thus, until further studies can elucidate the optimal modality of limb monitoring, an assortment of techniques are recommended in the presence of large bore indwelling arterial sheaths to ensure early detection of impaired tissue perfusion. In the event of disagreement between monitoring techniques, a multidisciplinary approach is recommended to aid interpretation of conflicting findings.…”