222 The prognostic value of the Ankle-Brachial Index to predict peri-operative mortality and cardiovascular events after major non-cardiovascular surgery

Abstract

Patients with coronary artery disease (CAD) who undergo non-cardiovascular surgery are at higher risk of peri-operative cardiovascular (CV) events. While it is well known that patients with peripheral artery disease (PAD) are overall at high risk of CV events, little is known about their peri-operative prognosis in the setting of non-cardiovascular surgery (NCS). Compared to the conventional risk assessment prior to major NCS, this study assessed the incremental prognostic value of the ankle-brachial index (ABI), a screening tool for PAD, to predict peri-operative prognosis. In 423 consecutive patients (age 69 ± 11 yrs), we estimated the revised cardiac risk index (rCRI) and measured the ABI preoperatively. An ABI <0.90 or >1.40 was considered abnormal. Patients were divided into 3 groups: those with clinical CVD (including clinical PAD), those with asymptomatic PAD (no clinical CVD but abnormal ABI), and healthy subjects (no clinical CVD, normal ABI). The composite primary outcome combined death, non-fatal acute coronary syndrome, stroke or transient ischemic attack and overt heart failure during the perioperative period. The secondary outcome included similar events within the first month. Multivariate regression models were used, adjusted for age, sex and conventional risk factors. Eighty (19%) patients had clinical CVD. Subclinical PAD was newly discovered in 53 (12.5%) cases. The primary outcome occured in 53 (12.5%) cases and the secondary outcome in 55 (13%) cases. Subclinical PAD was an independent risk factor for the primary (Odds Ratio [OR]: 3.28; p = 0.008) and secondary outcomes (OR: 3.20; p = 0.009). Abnormal ABI was associated with the primary (OR: 1.91; p = 0.0499) and secondary outcomes (OR: 1.99; p = 0.034), independent of the rCRI. The measurement of ABI before major non-cardiovascular surgery is useful to detect those at high risk of peri-operative events, independent of the conventional clinical risk assessment.