Outcome of patients with reduced ankle brachial index undergoing open heart surgery with cardiopulmonary bypass

Abstract

Objectives: In open heart surgery using cardiopulmonary bypass, perfusion of the lower extremities is markedly reduced which may induce critical ischaemia in patients with pre-existing peripheral artery disease. Whether these patients have an increased risk for amputation and should better undergo peripheral revascularization prior to surgery remains unclear.

Methods: From 1 January 2009 to 31 December 2010, 785 consecutive patients undergoing open heart surgery were retrospectively included. In 443 of these patients, preoperative ankle brachial index (ABI) measurements were available. The cohort was divided into four groups: (i) ABI < 0.5, (ii) ABI 0.5-0.69, (iii) ABI 0.7-0.89 or (iv) ABI ≥ 0.9. Follow-up data of 413 (93.2%) patients were analysed with regard to mortality and amputations.

Results: The groups differed significantly in terms of age, cardiac risk factors, performed cardiac surgery and renal function. Postoperative delayed wound healing was significantly associated with lower ABI (25.9, 15.2, 27.0 and 9.6% in Groups I-IV, respectively, P = 0.003), whereas 30-day mortality was not significantly higher in patients with lower ABI (0, 4.3, 8.1 and 3.9%, respectively, P = 0.4). Kaplan-Meier models showed a significantly lower long-term survival over 4 years in patients with reduced ABI (P = 0.001, long-rank test) while amputations occurred rarely with only one minor amputation in Group II (P = 0.023).

Conclusions: Patients with reduced ABIs undergoing heart surgery showed more wound-healing disturbances, and higher long-term mortality compared with those with normal ABIs. However, no perioperative ischaemia requiring amputation occurred. Thus, reduced ABIs were not associated with increased peripheral risks in open heart surgery but ABI may be helpful in selecting the site for saphenectomy to potentially avoid delayed healing of related wounds in legs with severely impaired arterial perfusion.

Keywords: Ischaemia; Peripheral vascular disease; Surgery complications; Wound healing.