Letter by Magalhaes et al Regarding Article, “Long-Term Survival and Repeat Coronary Revascularization in Dialysis Patients After Surgical and Percutaneous Coronary Revascularization With Drug-Eluting and Bare Metal Stents in the United States”
To the Editor:
We attentively read the article by Shroff et al entitled, “Long-Term Survival and Repeat Coronary Revascularization in Dialysis Patients Following Surgical or Percutaneous Coronary Revascularization With Drug-Eluting Stents or Bare Metal Stents in the United States.”1 The authors present important data regarding this unique and underrepresented population.2 They have documented that dialysis patients undergoing revascularization still have poor long-term survival and that the cumulative probability of repeat revascularization is higher in the drug-eluting stent–percutaneous coronary intervention (PCI) cohort compared with the bare metal stent–PCI and the coronary artery bypass graft (CABG) groups. However, important methodological issues should be taken into consideration. (1) There is a lack of data on the index clinical presentation (stable versus unstable), which subsequently drives the coronary revascularization, either PCI or CABG. Most likely, patients who presented with acute myocardial infarction had undergone PCI as opposed to CABG, which may have somehow biased the study. As published previously, the 1-year mortality rate after the first acute myocardial infarction in this subset is >50%.3 (2) High rates of right censuring before the end point being analyzed can violate some of the assumptions under the Kaplan–Meier curves, thus limiting the power of the long-term survival estimations. (3) There is no control group comprising dialysis patients with coronary artery disease who did not undergo revascularization for any reason (clinical arm). (4) The survival improvement captured among the drug-eluting stent and CABG cohorts, between the 2 time points (2004 versus 2009), may have been influenced by the ongoing improvement of dialysis quality care metrics over the period evaluated. (5) There is a lack of myocardial functional tests, left ventricular function, and angiographic data. (6) The rates of repeat revascularization, as reported, did not take into consideration the staged procedures, which can also comprise a multivessel PCI strategy as opposed to the CABG, in which it truly represents a failed procedure. In our opinion, the conclusion as presented by the authors is far from definitive and should not discourage the use of drug-eluting stents as a viable revascularization method for this complex population.
Marco A. Magalhaes, MD
Israel M. Barbash, MD
Ron Waksman, MD
Department of Internal Medicine
Division of Cardiology
MedStar Washington Hospital Center
- © 2013 American Heart Association, Inc.