Spanish researchers found that the real-world risk of stent thrombosis is low, but while the profiles of patients with early and late thrombosis were different, the short-term prognosis is poor, especially when the restoration of normal flow has failed, according to a prospective registry published in the March 11 issue of the Journal of the American College of Cardiology.
José M. de la Torre-Hernández, MD, PhD, in the Hospital Marques de Valdecilla, Santander, Spain, and colleagues sought to assess the incidence, predictors and outcome of drug-eluting stent (DES) thrombosis in real-world clinical practice.
The investigators designed a large-scale, multicentered Estudio ESpañol sobre TROmbosis de stents FArmacoactivos Registry (ESTROFA) with 20 centers in Spain.
Between June 2002 and January 2007, the researchers examined 23,500 patients who were treated with 34,075 DES: 37 percent with sirolimus-eluting stents and 63 percent with paclitaxel-eluting stents. Of those patients, 301 developed definite stent thrombosis (ST) 24 acute, 125 subacute and 152 late ST, according to the investigators. The median follow-up was 22 months.
Of the late events, 62 occurred more than one year, very late ST, according to the researchers. They found cumulative incidence was 2 percent at three years. The anti-platelet treatment had been discontinued in 95 cases (31.6 percent).
The authors reported that no differences in incidences were found among stent types.
De la Torre-Hernández and colleagues also examined independent predictors for subacute ST analyzed in a subgroup of 14,120 cases with diabetes, renal failure, acute coronary syndrome, ST-segment elevation MI, stent length, and left anterior descending artery stenting. They also analyzed for late ST in patients with ST-segment elevation MI, stenting in left anterior descending artery and stent length.
Mortality at one-year follow-up was 16 percent and ST recurrence 4.6 percent. Older age, left ventricular ejection fraction less than 45 percent, nonrestoration of thrombolysis in MI flow grade 3, and additional stenting were independent predictors for mortality, according the researchers.
The authors said that their registry used angiographic documentation of ST and certainly underestimates the real incidence of ST; however, they found that the overall incidence of DES-associated documented thrombosis results are slightly higher than reported previously with BMS.