Background—Patients with prior atherosclerosis in 1 or more vascular territories (coronary, cerebrovascular, or peripheral arterial) who present with acute coronary syndromes have high cardiovascular risk and may benefit significantly from evidence-based therapies, yet whether these are used consistently is unknown.

Methods and Results—The Get With the Guidelines–Coronary Artery Disease database was queried to determine whether compliance with quality-of-care treatments for acute coronary syndrome patients was associated with the extent of prior vascular disease. A total of 143 999 patients enrolled at 438 sites between January 2000 and January 2008 were classified according to the absence (n=98 136; 68%) or presence of known preexistent atherosclerosis (before admission) in 1, 2, or 3 vascular territories (n=37 633 [26%], n=7369 [5%], and n=861 [0.6%], respectively). Overall in-hospital mortality was 5.3%, and mean length of stay was 5.6±6.7 days. Compared with patients without prior vascular disease, patients with prior vascular disease were older and had more comorbidities. They were less likely to undergo coronary revascularization and had longer duration of hospital stay and higher in-hospital mortality. After adjustment for clinical and hospital characteristics, compared with patients without prior vascular disease, patients with prior vascular disease had higher mortality and were less likely to receive 3 particular treatments (lipid-lowering therapy, smoking cessation counseling, and angiotensin-converting enzyme inhibitor for left ventricular dysfunction).

Conclusions—Compared with acute coronary syndrome patients without prior vascular disease, those with prior atherosclerosis had higher in-hospital mortality yet were paradoxically less likely to receive specific evidence-based acute coronary syndrome treatments, which can form the basis for targeted intervention.