Is Clopidogrel Superior to Ticlopidine for the Prevention of Stent Thrombosis? Results of a Multicenter Study


Michael J. Rinaldi
St. Elizabeth's Hospital & Medical Center
Boston, MA, USA

Patients who received an anti-platelet regimen containing clopidogrel were at greater risk of stent thrombosis compared with patients who received a regimen containing ticlopidine. The results suggest clopidogrel-containing regimens may provide less protection against stent thrombosis than ticlopidine-containing regimens.

In recent years, many members of the interventional cardiology community have substituted clopidogrel for ticlopidine as anti-platelet therapy after stenting. They switched to the newer thienopyridine derivative because of studies that show clopidogrel has a superior side effect profile, particularly in nuisance side effects such as skin rash and gastrointestinal problems.

One question that has not been answered is whether clopidogrel is superior to ticlopidine for preventing stent thrombosis. No study to date has had enough statistical power to prove this hypothesis. Indeed, several studies have pointed in the opposite direction.

Dr. Rinaldi and colleagues performed a multicenter, case-control study comparing the ability of these two anti-platelet agents to prevent stent thrombosis.

Some of the centers involved in this study included Vanderbilt University Medical Center, Mayo Clinic, and Duke University Medical Center, among others. A total of 14 clinical sites participated.

Investigators identified 197 cases of angiographically confirmed stent thrombosis, and then matched each case with a single control from the same institution. They reviewed charts to determine clinical variables and sent all angiograms to a core laboratory for quantitative coronary angiography.

Patients with stent thrombosis were significantly more likely to have received clopidogrel than controls (47% versus 34%).

@

Independent predictors of stent thrombosis included primary stenting for acute myocardial infarction, higher platelet counts before the procedure, longer stents, and hypertension. After controlling for these and other potentially confounding factors, investigators found a correlation between use of clopidogrel and increased risk of stent thrombosis.

At the end of this AHA oral presentation, Dr. Rinaldi concluded that anti-platelet regimens containing clopidogrel may not provide as much protection against stent thrombosis than regimens containing ticlopidine. He suggested that investigators undertake a randomized, controlled trial to answer this question definitively.


Reporter: Andrew Bowser