Use of Optimal Medical Therapy in PCI Patients
Abstract & Commentary
By Michael H. Crawford, MD, Editor
Source: Borden WB, et al. Patterns and intensity of medical therapy in patients undergoing percutaneous coronary intervention. JAMA 2011;305:1882-1889.
The Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) study showed that in patients with stable coronary artery disease (CAD) put on optimal medical therapy (OMT) that randomization to a percutaneous coronary intervention did not improve survival or prevent myocardial infarction. Thus, these authors interrogated the National Cardiovascular Data Registry (NCDR) Catheterization Percutaneous Intervention (PCI) subregistry to assess the use of OMT before and after PCI and before and after publication of COURAGE. Data from 19 months before COURAGE publication and data 3-24 months after COURAGE were examined. OMT was defined as therapy with aspirin or a thienopyridine, beta-blocker, statin, or documental contraindication to these therapies. Renin angiotensin system blocker use was also assessed in appropriate subgroups (i.e., ejection fraction < 40%). The study population included 467,211 patients (28% of the Cath PCI subregistry) who had elective PCI for stable CAD. In general, OMT use increased after PCI (65% vs 44%; P < 0.001). Before PCI, OMT was deployed in 43.5% before COURAGE and in 44.7% after, which was statistically significant (P < 0.001) but of little clinical importance. After PCI before COURAGE, OMT was used in 64% vs 66% after COURAGE (P < 0.001). The authors concluded that in stable CAD patients undergoing PCI, fewer than half were on OMT before PCI and about two-thirds were on OMT after PCI. The results were not clinically different after the COURAGE trial was published.
This study suggests that we are missing a large opportunity to improve patient outcomes after PCI is performed, since only about two-thirds were on OMT 2 years after PCI. By comparison in the COURAGE trial, 79% were on OMT at 5 years. They point out that this deficiency is not just the purview of the interventional cardiologist, but also the responsibility of the primary care provider. Perhaps there needs to be better coordination between these providers.
Publication of the excellent results of OMT in the COURAGE trial did not appreciably change the number of patients on OMT. This observation shows the difficulty of translating clinical trial data into practice and it is not clear why. Perhaps practitioners do not believe the results or think they do not apply to their patients. However, when the individual medications are examined, antiplatelet therapy increased from 89% before PCI to 99% afterward. Of course the role of antiplatelet therapy after PCI has been extensively studied and reported upon. Beta-blockers went from 63% to 75% and statins from 63% to 84%. These are individually significant improvements, but you had to be on all three medications to qualify as OMT. This suggests that contraindications to one or more medications may not have been documented or were missed by those reviewing the records.
Other factors may have impacted the decision to prescribe certain drugs. There are fewer data on the benefits of beta-blockers beyond angina prevention in patients with chronic stable CAD. Also, some patients not on statins may have had the high triglyceride low HDL pattern and were put on niacin or fibrates. Renin angiotensin blockers may have been avoided in the hospital due to fear of augmenting renal damage caused by the contrast agents used in cardiac catheterization and were never started after discharge. Data have shown that patients are more likely to remain on drugs started in the hospital than those started later.
It is likely that there is an opportunity to improve our care of stable CAD patients, but the magnitude may not be as great as this study suggests.