Secondary Prevention After Coronary Artery Bypass Graft Surgery: Findings of a National Randomized Controlled Trial and Sustained Society-Led Incorporation Into Practice

Study Questions:

Can a low-intensity continuous quality improvement intervention be used to enhance secondary prevention adherence after coronary artery bypass graft surgery (CABG)?


A total of 458 hospitals participating in the Society of Thoracic Surgeons National Cardiac Database and treating 361,328 patients undergoing isolated CABG were randomized to either a control or an intervention group. The intervention group received continuous quality improvement materials designed to influence the prescription of the secondary prevention medications at discharge (i.e., aspirin, angiotensin-converting enzyme [ACE] inhibitors, beta-blockers, lipid treatment). The primary outcome measure was discharge prescription rates of the targeted secondary prevention medications at intervention versus control sites, assessed by measuring preintervention and post-intervention site differences.


Mean age was 64 years old, 75% were men, 34% were diabetics, 75% were hypertensive, and 50% of CABGs were elective. Prerandomization treatment patterns and baseline data were similar in the control (n = 234) and the treatment (n = 224) sites. The mean change in use of treatments was 2.9% versus 4.2% for aspirin (p = NS), 9.7% versus 12.2% for beta-blockers (p = 0.032), 6.4% vs. 13.1% for ACE inhibitors (p < 0.001), and 13.1% vs. 15.75% for lipid treatment (p = 0.017), and for all versus not all, 12.1% versus 16.7% (p = 0.001). Individual medication use and composite adherence increased over 24 months in both groups, with a markedly more rapid rate of adherence uptake among the intervention hospitals and a statistically significant therapy hazard ratio in the intervention versus control group for all four secondary prevention medications. Improvement was limited to the nonacademic centers.


Provider-led, low-intensity continuous quality improvement efforts can improve the adoption of care processes into national practice within the context of a medical specialty society infrastructure. The findings of the present trial have led to the incorporation of study outcome metrics into a medical society rating system for ongoing quality improvement.


The study demonstrates how large medical society data sets designed to assess outcome can be used to further enhance quality of care without significant incremental costs. The study was conducted from 2003-2005, but the important message is that major impacts on outcome can result from relatively simple encouragements to cardiac surgeons. Among the opportunities to increase evidence-based care include a pharmacy specialist, nurse practitioner, or cardiology consultation prior to discharge of cardiac surgical patients with the responsibility of selecting which of the ‘evidence-based treatments’ is indicated, and more importantly, the optimal dosing schedule, drug information, and needed follow-up to assure adherence.

Clinical Topics: Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Prevention, Cardiac Surgery and Arrhythmias

Keywords: Outcome Assessment (Health Care), Quality Improvement, Follow-Up Studies, Secondary Prevention, Societies, Medical, Medicine, Coronary Artery Bypass

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