Unfractionated heparin (UFH) has overtaken bivalirudin as the anticoagulant of choice for treating end-stage renal disease (ESRD) patients undergoing PCI, according to a new study, but UFH may be associated with worse in-hospital outcomes.

Jeffrey B. Washam, PharmD, and colleagues studied more than 70,000 ESRD patients from the national CathPCI registry who had procedures from July 2009 through September 2015 and were treated with either bivalirudin alone or UFH monotherapy. Bivalirudin was used in 51.3 percent of patients overall, while UFH became the more popular option in 2014 and was used 64 percent of the time in the final three months of the study.

However, patients receiving bivalrudin saw lower rates of in-hospital bleeding (7 versus 9.5 percent) and in-hospital mortality (2.6 versus 4.2 percent). After risk adjustment, the odds of in-hospital bleeding and mortality were lowered by 18 and 13 percent, respectively, with bivalirudin.

“Although previous observations have associated chronic kidney disease with worse outcomes in patients undergoing PCI, this contemporary analysis highlights the increased risks in patients with ESRD,” Washam and colleagues wrote in Circulation: Cardiovascular Interventions. “A recent analysis in the overall population from the CathPCI registry reported an in-hospital bleeding event rate of 1.7 percent. Comparatively, we observed a rate of 8.2 percent for this same outcome.

“In addition, a separate analysis from the CathPCI registry reported in hospital mortality rates for patients undergoing primary PCI for STEMI (ST-segment elevation myocardial infarction) in the United States to be 5.6%. In the cohort of patients with ESRD undergoing primary PCI for STEMI in this analysis, we observe an in-hospital mortality rate of 20.4 percent.”

In comparing the two anticoagulants, the authors noted patients using UFH had more comorbidities such as heart failure, a previous MI or peripheral vascular disease, and were more likely to have experienced cardiac arrest or cardiogenic shock within 24 hours of PCI.

“Although many of these characteristics were covariates in the statistical models used for adjustment, it is possible that we were not able to fully account for these, thereby subjecting the results to possible residual confounding,” they wrote.

Another limitation of the study is the lack of information on medication dosage each patient received.

The researchers believe their findings warrant further research, particularly because individuals with ESRD have traditionally been underrepresented in interventional cardiology trials.

“Given the observational nature of this analysis coupled with the four-fold higher rate of in hospital bleeding and mortality in patients with ESRD undergoing PCI compared with the overall population of patients undergoing PCI, a randomized trial of antithrombotic strategies in patients ESRD undergoing PCI is warranted to guide clinical practice,” they wrote.