(P200) MYOCARDIAL ISCHEMIC BURDEN IN PATIENTS WITH PERIPHERAL ARTERY DISEASE UNDERGOING MYOCARDIAL PERFUSION IMAGING

Background: Given its increasing prevalence and associated cardiovascular morbidity, peripheral artery disease (PAD) poses a substantial health burden to society. We evaluated whether PAD remains associated with major adverse cardiovascular events (MACE) after accounting for relevant comorbidities and SPECT myocardial perfusion imaging (MPI) findings.

METHODS AND RESULTS: We included 45,252 patients undergoing MPI from a large, international, multicenter registry. Medical history was collected at the time of clinical reporting. Images were processed at the core laboratory, including quantitative assessment of myocardial perfusion using total perfusion deficit (TPD), which is categorized as: no deficit (TPD=0%), very minimal deficit (0%< TPD < 1%), minimal deficit (1%≦TPD < 5%), mild deficit (5%≦TPD < 10%), and moderate-to-severe deficit (TPD≥10%). We evaluated associations of PAD with MACE, including death, admission for unstable angina, myocardial infarction, or late coronary revascularization (>90 days).

During a median follow-up of 3.6 (IQR: 2.6-4.9) years, 5,932 patients (13.7%) experienced at least one MACE. Patients with PAD were more likely to have a prior diagnosis of CAD (53.9% versus 16.1%) and more extensive stress TPD (4.4% vs 2.5%). Compared to patients without CAD or PAD, the presence of PAD alone (HR:1.66, 95%CI:1.51-1.82, p< 0.001), CAD alone (HR:2.69, 95%CI:2.53-2.85), or concomitant PAD and CAD (HR:2.45, 95%CI:2.26-2.64) were associated with an increased risk of MACE. To further evaluate the independent risk associated with PAD, we identified 7022 patient pairs using propensity-score matching to account for imaging parameters and comorbidities, including the history of CAD. Prior to matching, there was lower MACE-free survival across the severity of myocardial ischemia for patients with PAD (p < 0.001), except for patients with moderate-to-severe perfusion deficit (TPD >10%). However, after matching, patients with PAD demonstrated a comparable risk of MACE as patients without PAD (p=0.064). When stratified based on TPD categories, the presence of PAD was associated with greater MACE risk among patients with very minimal perfusion deficit (p=0.006).

Conclusion: Patients with PAD are more likely to have concomitant CAD and larger myocardial perfusion deficits. PAD was not associated with increased MACE risk after accounting for these factors. However, it does identify higher-risk patients, particularly among patients with minimal perfusion deficits, who may benefit from more aggressive medical therapy.