Circulation: Stent parameters may be a potent predictor of risk
Measuring a PCI procedure by metrics such as the number or length of stents implanted may help predict the likelihood of adverse events and may also help identify which patients will benefit most from therapy with GP IIb/IIIa inhibitor eptifibatide (Integrilin), according to the ESPIRIT randomized trial published in the February issue of Circulation: Cardiovascular Interventions.

In the analysis of 1,983 patients receiving a stent in the ESPRIT non-urgent PCI trial, rates of the major adverse cardiac event (MACE) endpoint (death, MI, urgent target vessel revascularization or thrombotic bailout) at 48 hours and one year were correlated with stent parameters (number implanted, total length of implanted stent, stent diameter and total stented vessel area) and then analyzed by randomization to eptifibatide (from Millennium Pharmaceuticals and Schering-Plough) or placebo.

"Non-urgent PCI is traditionally considered a low-risk procedure, but can actually be extremely complex. This analysis suggests to clinicians that very basic information, such as the number of stents or their length, may help determine the probability of a complication, and it suggests the potential benefit of GP IIb/IIIa blockade with eptifibatide, especially in patients receiving more or longer stents, said the study's lead author James E. Tcheng, MD, from the Duke Clinical Research Institute at Duke University Medical Center in Durham, N.C.

In the placebo group, the researchers reported that MACE increased with number of stents implanted, total stent length and total stented vessel area. By stent parameters, MACE at 48 hours was reduced in the eptifibatide group at stent lengths of 18 to 30 mm, 30 mm; stent diameters of 2.5 to 3.5 mm; and with two stents implanted.

In the placebo group, the investigators observed near-linear relationships observed between both increasing stent length and increasing stented vessel area and MACE at 48 hours and one year; these gradients were flattened in the eptifibatide group.

The authors noted that the study has several limitations, including the usual limitations of retrospective analyses.

Tcheng and colleagues concluded that a new risk model that encompasses multiple factors--clinical, morphological and procedural--may better predict risk and further distinguish patients benefiting from intensive peri-procedural antiplatelet therapy.

"The findings suggest a mechanism for explaining MACE complication rates following stent angioplasty--that the actual amount of vessel area covered by the stent is directly proportional to, and is thus largely responsible for, adverse events following stent PCI," Tcheng said.