Drug-eluting stents (DES) that open blocked coronary arteries cause no more risks for death or heart attack than bare-metal stents (BMS), according to a late-breaking outcomes trial presented at the American Heart Association’s conference held this week in Orlando, Fla.
The Massachusetts stent trial, funded by the state’s Department of Public Health, compared death rates between patients who received DES and those who received BMS. The researchers examined the records of all adults undergoing percutaneous coronary intervention (PCI) who had a stent implanted between April 1, 2003 and Dec. 31, 2004 at acute care non-governmental hospitals.
“This is the largest study of patients comparing DES and BMS for long-term outcomes in the United States,” said Laura Mauri, MD, principal investigator, and assistant professor of medicine at Harvard Medicine School and Brigham and Women’s Hospital in Boston.
“It was previously established that DES make it less likely that patients will need repeat procedures within the first year after a stent procedure,” Mauri said. “What we were less certain about before this study was the long-term clinical outcomes of the safety of DES compared to bare metal stents in the general population.” She noted previously only relatively small sects of people were compared for efficacy results.
The researchers examined 21,024 patients from a state database of PCI patients, but excluded 1,538 non-residents and another 569 patients because the administrative files were not linkable, leaving the group with 18,917 patients. Finally, they excluded 1,191 patients with both stent types, resulting in a cohort of 11,516 DES-only patients and 6,210 BMS-only patients.
The patient follow-up lasted at least two years after a stent implantation.
One limitation for the trial was that the researchers were not able to track the pharmaceutical records because they were integrated with the administrative records. As a result, they did not have access to that data, according to Mauri.
The researchers compared the mortality, heart attacks and revascularization procedures, either bypass surgery or another PCI, between the two groups. The scientists matched pairs of stent patients, comparing 5,441 DES patients and 5,441 BMS patients for 63 different variables. The adjusted incidence of death at 2 years was 9.4 percent for those with DES and 11.9 percent for those with BMS. There was also no statistical difference for MI, but the rate of revascularization was lower in patients treated with DES compared with BMS.
Mauri added that the “very large study with long-term follow-up reflects contemporary U.S. practice – where most patients receive DES – and it includes all patients who were undergoing PCI – not just those who would have qualified for a randomized trial.”