Author + information
- Seung-Jung Park, MD, PhD⁎ ( and )
- Duk-Woo Park, MD, PhD
- ↵⁎Asan Medical Center, Department of Cardiology, University of Ulsan College of Medicine, 388-1 Poongnap-dong, Songpa-gu, Seoul, Republic of South Korea
We thank Dr. Head and colleagues for their remarks concerning our paper (1). Although a randomized clinical trial (RCT) is the ideal method for measuring true treatment effects, the RCT does not necessarily provide the final answer to treatment effectiveness, as there are many restrictions that limit generalizability of study findings (2).
There are many considerations when one is choosing a treatment strategy for coronary revascularization (3). In real practice, it is mostly likely that patients with less complex anatomy of atherosclerotic coronary artery disease (CAD) and less comorbidity tend to be more often referred for percutaneous coronary intervention (PCI), whereas those with more severe anatomic complexity and coexisting conditions tend to be preferentially considered for coronary artery bypass grafting (CABG). These factors, therefore, may cause potential bias due to confounding by indication in comparative clinical strategies studies (4).
Several comparisons of CABG with PCI suggest a strong relation between the extent of coronary disease and the relative effectiveness of these procedures on survival (5,6). In particular, clinical registry studies have reported that patients with the least extensive coronary disease (i.e., 2-vessel disease) have better survival after PCI, whereas patients with the most extensive disease (i.e., 3-vessel disease) have better survival after CABG. Our registry data collected consecutive “real world” patients who received multivessel revascularization with minimal exclusion criteria. Therefore, the major difference in patient inclusion of our study and the SYNTAX (Synergy Between PCI With TAXUS and Cardiac Surgery) trial was the enrollment of patients with 2-vessel disease. A more beneficial effect of PCI with drug-eluting stents relative to CABG for patients with less severe, 2-vessel disease is the most likely explanation for our contradicting results compared with the SYNTAX trial. Referring patients with 2-vessel disease for CABG is common in clinical situations, but this subset was not included in the SYNTAX trial.
Although findings of observational studies should be interpreted with caution due to selection bias and unmeasured, multiple confounders, well-conducted observational studies can address long-term effectiveness and safety problems of revascularization procedures in a broader array of patients by the optimal judgment of the treating physician in routine practice, and may more accurately reflect “real world” experience.
- American College of Cardiology Foundation
- Park D.W.,
- Kim Y.K.,
- Song H.G.,
- et al.
- Park S.J.,
- Park D.W.