Repeated episodes of stent thrombosis common

When a clot develops inside a coronary stent, it can block blood flow to the heart, potentially causing a heart attack or even death.

A single incident of stent thrombosis is bad enough, but a new study suggests that one in six patients can expect to experience at least one repeat episode. According to the Dutch Stent Thrombosis Study, among the strongest predictors of recurrent stent thrombosis is implantation of an additional stent during emergency treatment of the first episode.

The study will be reported in a Late-Breaking Clinical Trials session at the SCAI Annual Scientific Sessions in Partnership with ACC i2 Summit (SCAI-ACCi2) in Chicago. SCAI-ACCi2 is a scientific meeting for practicing cardiovascular interventionalists sponsored by the Society for Cardiovascular Angiography and Interventions (SCAI) in partnership with the American College of Cardiology (ACC).

Jochem Wouter van Werkum, MD, a cardiologist at St Antonius Hospital, Nieuwegein, the Netherlands, led the study. He and his colleagues enrolled a total of 437 consecutive patients who had stent thrombosis confirmed by angiography between January 2004 and February 2007. The researchers collected data on clinical characteristics (for example, diabetes, age and duration of antiplatelet therapy), angiographic characteristics (for example, undersizing of the stent, dissection and whether the lesion was located at an arterial branchpoint), and procedural characteristics (for example, whether a drug-eluting or bare-metal stent was used and the length and diameter of the stent).

The researchers found that 74 of the 437 patients (16.9 percent) experienced multiple episodes of stent thrombosis. Of these, 61 patients had two episodes of stent thrombosis, 12 patients had three episodes and one patient had four episodes. Further analysis revealed three independent predictors of repeat stent thrombosis. Patients who had an additional stent implanted during emergency treatment for the first episode of stent thrombosis were 4.2 times as likely as other patients to experience a repeat episode of stent thrombosis (p<0.0001). Patients with a previous heart attack faced 2.6 times the usual risk of repeat stent thrombosis (p<0.001), and patients who developed thrombosis long after stent implantation (late stent thrombosis) faced 2.1 times the usual risk of a repeat episode (p=0.0127).

Dr. van Werkum and his colleagues concluded that additional stent placement at the time of emergency treatment for the first stent thrombosis should be avoided.

Dr. van Werkum will present the results of the "Dutch Stent Thrombosis Study" study on Saturday, March 29 at 8:15 a.m. CDT in the Grand Ballroom, S100.

About SCAI

Headquartered in Washington, DC, the Society for Cardiovascular Angiography and Interventions is a 4,000-member professional organization representing invasive and interventional cardiologists in over 60 nations. SCAI's mission is to promote excellence in invasive and interventional cardiovascular medicine through physician education and representation, and advancement of quality standards to enhance patient care. SCAI's annual meeting has become the leading venue for education, discussion, and debate about the latest developments in this dynamic medical specialty.

About ACC

The American College of Cardiology is leading the way to optimal cardiovascular care and disease prevention. The College is a 34,000-member nonprofit medical society and bestows the credential Fellow of the American College of Cardiology upon physicians who meet its stringent qualifications. The College is a leader in the formulation of health policy, standards and guidelines, and is a staunch supporter of cardiovascular research. The ACC provides professional education and operates national registries for the measurement and improvement of quality care.