Coronary plaque burden and computed tomography-derived fractional flow reserve are predictors of 5-year mortality in peripheral artery disease patients with no known coronary artery disease

Objective: Patients with peripheral artery disease (PAD) have poor long-term survival due to coexisting coronary artery disease (CAD), which is often asymptomatic and undiagnosed. Coronary computed tomography angiography (CTA)-derived quantitative plaque analysis (CT-QPA) and fractional flow reserve (FFR _CT) are established predictors of cardiovascular death in patients with symptomatic CAD. However, their prognostic value in patients with PAD with no symptoms of CAD undergoing peripheral vascular surgery is unknown. This study assessed the value of CT-QPA and FFR _CT in predicting 5-year mortality in patients with vascular surgery with no known CAD. Methods: Patients with PAD with no evidence of CAD who were cleared for elective peripheral vascular surgery were enrolled in a prospective study of preoperative CTA and FFR _CT to evaluate cardiac risk. Lesion-specific coronary ischemia was defined as FFR _CT ≤ 0.80, with severe ischemia defined as FFR _CT < 0.75. CT-QPA analysis provided quantitative data on total plaque volume (TPV) and plaque characteristics. Vascular surgery was performed on all patients with no perioperative mortality. Postoperatively, all patients received guideline-directed medical therapy with no elective coronary revascularization. The primary endpoint was all-cause death at 5 years, assessed by Cox regression analysis. Results: Among 124 patients with PAD with no cardiac history or symptoms (mean age, 67 ± 8 years; 76% men), coronary plaque burden was high (median [TPV] 550 mm ³ [IQR, 299-1156]), and 53% had asymptomatic (silent) coronary ischemia (FFR _CT ≤ 0.80). During a 5-year follow-up, 32 patients (26%) died. Nonsurvivors had nearly twofold higher TPV compared with survivors (975 vs 458 mm ³; P < .001), with significant increases in calcified (P < .001), noncalcified (P < .001), and low-attenuation plaque (P = .038). Five-year mortality in patients with TPV > 750 mm ³ was 46% compared to 4% in those with TPV < 250 mm ³ (log-rank P < .001). Both TPV ≥ 550 mm ³ (hazard ratio, 3.6; 95% confidence interval, 1.6-7.9; P = .002) and FFR _CT ≤ 0.80 (hazard ratio, 2.1; 95% confidence interval, 1.0-4.5; P = .045) were predictors of increased mortality risk. Five-year mortality in patients with both high plaque and coronary ischemia was 42% compared with only 10% in patients with low plaque and no ischemia (log-rank P = .006). Conclusions: In patients with PAD with no known CAD undergoing elective vascular surgery, coronary plaque burden and silent coronary ischemia detected by CT-QPA and FFR _CT were predictors of a 5-year mortality. Coronary CTA with quantitative plaque and FFR analysis should be considered for comprehensive cardiac risk stratification in patients with vascular surgery, regardless of cardiac symptoms.