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Guideline-directed medical therapy suboptimal in contemporary coronary revascularization trials
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Compliance with guideline-directed medical therapy is suboptimal in contemporary coronary revascularization clinical trials and is even lower after CABG compared with PCI, researchers concluded in a study.
Ana-Catarina Pinho-Gomes, MSc(Hons), from the department of cardiac surgery at Oxford University Hospitals NHS Trust, United Kingdom, and colleagues performed a systematic review and meta-analysis to evaluate compliance with guideline-directed medical therapy in five landmark randomized controlled trials that compared PCI with drug-eluting stents vs. CABG: SYNTAX, FREEDOM, PRECOMBAT, BEST and EXCEL.
“[There is a] lack of detail provided about concurrent medical therapy in contemporary trials of coronary revascularization. We were concerned that compliance with medication that has shown compelling benefits in terms of secondary prevention of CV events could be differentially distributed between study groups (PCI and CABG),” Pinho-Gomes told Cardiology Today’s Intervention. “If this was the case, then the comparison between long-term outcomes of PCI vs. CABG could be influenced/modified at least partially by the different compliance with optimal medical therapy.”
Low compliance
For this study, guideline-directed medical therapy was defined in two ways: a combination of any antiplatelet agent, beta-blocker and statin or a combination of any antiplatelet agent, beta-blocker, statin and ACE inhibitor and/or angiotensin receptor blocker.
Results showed low overall compliance with the first combination of guideline-directed medical therapy, which decreased from 67% at 1 year to 53% at 5 years. Similarly, compliance with the second combination of guideline-directed medical therapy was even lower and also decreased from 40% at 1 year to 38% at 5 years.
Additionally, at all time points, compliance for both definitions of guideline-directed medical therapy was higher among patients who underwent PCI vs. CABG.
The researchers also found an inverse association between lower compliance with the first combination of medical therapy at 5 years and clinical outcomes, including all-cause mortality, MI and a composite endpoint of all-cause mortality, MI and stroke.
“Unfortunately, the results were not surprising. We were expecting a low proportion of compliance in these trials, in line with what has been shown in observational studies. The cost and close follow-up required to achieve ideal compliance rates with medical therapy likely justify these unsatisfactory rates of compliance. We were also expecting compliance to be superior in PCI vs. CABG and this may have impacted the comparison of outcomes between those interventions,” Pinho-Gomes said.
She noted, though, that the researchers were surprised by the lack of data on concurrent medical treatment in some trials.
“The fact that some trials failed to collect those data demonstrates the lack of awareness of the importance it plays on preventing secondary CV events and optimizing the outcomes of any revascularization strategy,” Pinho-Gomes said.
Implications for research, clinicians
In an accompanying editorial, Marc Ruel, MD, MPH, from the University of Ottawa Heart Institute, Canada, and Alexander Kulik, MD, MPH, from the Lynn Heart and Vascular Institute, Boca Raton Regional Hospital, and Charles E. Schmidt College of Medicine, Florida Atlantic University, placed the findings in context.
“The uniqueness of this paper represents its greatest strength, as no study to date had previously focused on comparative administration rates of secondary preventative therapies after coronary revascularization, in the context of pooled clinical trials,” they wrote.
However, Ruel and Kulik also highlighted certain limitations, such as the inclusion of only a few clinical trials, the lack of individual patient-level data on clinical outcomes and the variability in compliance among the studies. Additionally, without a complete pharmaceutical database, the researchers could not assess true patient adherence rates. Also, the researchers could not discriminate between patient noncompliance and physician nonprescription, as these data were not collected in the trials, Ruel and Kulik wrote.
Nevertheless, the results have important ramifications for research as well as clinical practice, according to Pinho-Gomes.
“For those who conduct trials, it is crucial to optimize compliance with guideline-recommended medical therapy to allow for a fair comparison between PCI and CABG and to provide the full ‘revascularization package of care,’ which includes mechanical revascularization and lifelong medical therapy. Randomized controlled trials should set the gold standard for real-world clinical practice to follow,” she told Cardiology Today’s Intervention.
“Moreover, the take-home message for all surgeons and cardiologists is that the interpretation of the findings of landmark randomized controlled trials of coronary revascularization need to take into account the potential influence of differential compliance with guideline-directed medical therapy in the study arms,” Pinho-Gomes said. – by Melissa Foster
For more information:
Ana-Catarina Pinho-Gomes, MSc(Hons), can be reached at anacatarina.pinhogomes@gmail.com.
Disclosures: One researcher reports he has received research support from Amgen. Pinho-Gomes and all other authors report no relevant financial disclosures. Kulik reports he has received research support from AstraZeneca and Pfizer. Ruel reports no relevant financial disclosures.
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