New York, NY - GP-IIb/IIIa-inhibitor use during primary angioplasty is associated with improved in-hospital survival, according to a new registry study [1].

The study, published in the February 15, 2007 issue of the American Journal of Cardiology, was conducted by a group led by Dr Vankeepuram Srinivas (Montefiore Medical Center, New York).

Srinivas explained to heartwire that there have been some randomized studies of GP IIb/IIIa blockers in primary angioplasty, but these have mainly been quite small, and although they have shown improvements in TIMI-3 flow, infarct size, and even reinfarction, none have been large enough to show an effect on mortality.

Therefore, to shed more light on this issue, he and his colleagues conducted an observational study using data from the New York state registry of patients undergoing angioplasty. They selected the 7321 patients undergoing primary angioplasty between 2000 and 2003 and then examined GP-IIb/IIIa-blocker use in this group. Propensity analysis was used to account for the nonrandomized use of GP IIb/IIIa inhibitors.

Results showed that overall, 78.5% of patients who underwent primary angioplasty received GP IIb/IIIa inhibitors. In-hospital mortality was significantly lower with GP IIb/IIIa use (3% vs 6.2%), and this reduction remained significant after adjustment for both propensity score and clinical characteristics.

Srinivas told heartwire that around one third of patients received abciximab, 46% received one of the small-molecule agents (tirofiban or eptifibatide), and 22% did not receive any such treatment. He said he was "surprised" by the relatively high use of tirofiban and eptifibatide, as there were fewer data on these agents than for abciximab in this indication, noting that the ACC/AHA guidelines give a class 2a recommendation for the use of abciximab in primary PCI, but only a class 2b recommendation for tirofiban and eptifibatide.

The top predictor for using a IIb/IIIa blocker was symptoms of acute MI onset within six hours. Srinivas said this made sense, as patients tended to be given the IIb/IIIa blocker in the emergency department, and doctors were probably hoping that early use of these agents might improve clot lysis.

Srinivas acknowledged that this observational study is not as reliable as a randomized trial, but he pointed out that a randomized trial would have to be very large to show an effect on mortality and such a trial would probably not be conducted at this time. "In the absence of randomized data, we have to rely on observational studies, and we did perform a careful propensity analysis and adjusted for many factors," he said.

"Our results are encouraging in that treatment with IIb/IIIa inhibitors does appear to be the norm in this indication. The impressive reduction in mortality associated with this treatment is consistent with the encouraging results on other end points seen in previous studies. Based on these data, I am using IIb/IIIa blockers routinely in primary-angioplasty patients in my practice, unless there is a specific contraindication," Srinivas commented.

The top three predictors for not using a IIb/IIIa blocker in this primary PCI population were old age, contraindication to thrombolysis, and previous stroke. Srinivas said: "Our data suggest that these agents are being underused in the elderly, and as the relative benefit appears to be similar across all risk groups, the elderly could benefit the most from such treatment. Our results showed a mortality rate of 6% to 8% in elderly patients undergoing primary angioplasty vs under 3% for younger patients. If the elderly also showed a 40% reduction in mortality with IIb/IIIa blockers, we could cut death rates dramatically." He also noted that elderly patients are also more likely to be undergoing primary PCI in preference to thrombolysis, and the risk of intracranial hemorrhage with thrombolysis is greater in these patients. "Doctors may be frightened of using IIb/IIIa blockers in the elderly for the same reason, but intracranial hemorrhage has not been shown to be problem with these agents," he added.