Introduction: Peripheral artery disease (PAD) is considered a coronary risk equivalent and is associated with increased risk of adverse cardiovascular (CV) events. Yet, as compared to other high-risk groups, little is known about the relative risk of adverse CV events in patients with PAD presenting with chest pain and without known coronary disease.
Methods: Among 10,003 patients enrolled in the PROMISE trial, 220 (2.2%) patients had PAD, defined as history of PAD, carotid revascularization, or carotid stenosis ≥ 50%. Patients with PAD were matched 1:3 to high-risk controls (HRC) (no PAD and Framingham Risk Score ≥ 20%) based on age, sex, diabetes, and CKD (gfr < 60 ml/min/m2). Logistic and Cox regression models were used to assess differences in referral to invasive coronary angiography (ICA) and clinical outcomes.
Results: Among the matched population, 219 patients had PAD and 657 were HRC. Patients with PAD more often presented with dyspnea and were less likely to have metabolic syndrome, but there were no other significant differences in baseline characteristics or type of presenting chest pain compared to HRC. Aspirin use (64.8% vs. 46.9%; p=<0.001) and statin use (59.6% vs. 47.0%; p=0.001) were more common in those with PAD than HRC. Mean and median Framingham Risk was lower in patients with PAD as compared to HRC (p<0.001). The distribution of Diamond and Forrester scores for the likelihood of CAD was similar between the PAD group and HRC (low risk: 27.9% vs. 31.7%; intermediate risk: 64.4% vs. 59.8%; high risk: 7.8% vs. 8.5%; p=ns for all). After adjustment for chest pain type, referral to ICA was similar between PAD (18.3%) and HRC (14.3%) (adjusted OR = 1.32; p=0.19). Yet, composites of death/MI/unstable angina hospitalization and CV death/MI were greater in those with PAD (adjusted HR = 2.55 [95% CI = 1.41-4.61]; adjusted HR = 2.72 [95% CI = 1.40-5.31]; adjusted HR = 3.69 [95% CI = 1.71-7.94], respectively).
Conclusions: Despite lower Framingham Risk and greater use of statins and aspirin, stable chest pain patients with PAD were 3.5 times per likely to experience CV death or MI as compared to a group of matched, high-risk controls. Future work will be necessary to improve risk prediction and outcomes in PAD.