NEW YORK (Reuters Health) – Patients hospitalized for acute coronary syndrome (ACS) are less likely to survive until discharge if they have a known history of prior atherosclerosis, new research indicates.

The reason for the higher mortality may be that the patients with preexisting vascular disease received specific evidence-based ACS treatment less frequently than their counterparts. Compared with patients with no prior history of atherosclerosis, those with such a history are also less likely to undergo coronary revascularization.

“The results are surprising,” noted Dr. Emmanouil S. Brilakis of the Dallas VA Medical Center. “Patients with prior atherosclerosis have a higher risk for complications compared to those without prior atherosclerosis. Therefore, one would expect them to be more likely to receive these evidence-based treatments.”

To investigate these issues, Dr. Brilakis and co-researchers analyzed data from the American Heart Association’s “Get With The Guidelines-Coronary Artery Disease” database. Of 332,050 persons entered into the database between 2000 and 2008, patients without ACS, those who left, or were missing complete medical history were excluded. The final cohort included 143,999 patients at 438 sites.

Prior vascular disease included a history of ACS, peripheral arterial disease, and/or stroke. Twenty-six percent had a history of one of these, 5% a history of two, and 0.6% a history of three; 68% had no history of prior vascular disease, the authors report in the August 18 issue of Circulation.

In-hospital mortality varied from 4.7% among those with no prior atherosclerosis, 6.6% for those with one manifestation, 8.9% for two and 9.1% for three (p < 0.001).

The proportion of patients who had percutaneous coronary revascularization followed a similar pattern (57%, 43%, 33%, and 26%, p < 0.001). "The association remained significant after multivariable adjustment," the authors maintain, "which suggests that prior vascular disease carries independent prognostic value."

They were also less likely to receive (when indicated) lipid-lowering therapy, smoking cessation counseling, and angiotensin-converting-enzyme inhibitors.

Dr. Brilakis and his associates suggest that this pattern may be due to more comorbidities, concern for drug interactions, and higher cost. This theory is supported by the finding that a history of vascular disease was associated with a greater use of aspirin and beta-blockers, which are considered safe and efficacious, easy to use, and less expensive.

In summary, the research team writes, “Patients with prior vascular disease may be an easily identifiable patient group that could derive significant benefit from targeted interventions that aim to improve ACS care.”

Reference:
Circulation 2009;120.