Incidence, predictors and outcome of drug-eluting stent thrombosis in real-world practice.

BACKGROUND

Traditionally, stent thrombosis (STH) has been regarded as a complication of percutaneous coronary interventions during the first 30 post-procedural days. However, delayed endothelialization associated with the implantation of drug-eluting stents (DES) may extend the risk of thrombosis beyond 30 days. Data are limited regarding the risks and the impact of this phenomenon outside clinical trials.

OBJECTIVES

To evaluate the incidence, predictors and clinical outcomes of STH and premature discontinuation of thienopyridines after implantation of DES in real-world practice.

METHODS

We prospectively collected data from consecutive unselected patients who underwent at least 1 DES implantation at our center from February 2006 until January 2007. The patients were followed by a phone interview or by collecting data from admission files over the course of 2 years after the implantation. Confirmed and suspected STH was defined as accepted in the medical literature.

RESULTS

Three hundred fourteen patients were successfully treated with DES (436 lesions). At 20 ± 6.7 months' follow up (median 22 months), 14 patients (4.4%) had STH (incidence density 2.7 cases/100 patients-years). Five patients had early thrombosis (0-30 days), 5 patients had late STH (31-360 days from the procedure) and 4 patients had very late STH (> 360 days). Five of the 14 patients with STH died (case fatality rate, 36%). In multivariant logistic regression analysis, history of a non-cardiac thrombotic event was a risk factor for STH (p = 0.006, odds ratio [OR] 7.7, confidence interval [CI] 1.8-32.9). Clopidogrel therapy lasting less than 3 months was an independent predictor of late and very late STH (p = 0.001, OR 10.8, CI 2.7-42.9). Independent predictors of early discontinuation of thienopyridines (≤ 3 months) were Arab ethnic origin (p = 0.005, OR 19.2, CI 2.4-142), absence of cardiology follow up (p = 0.05, OR 4.7, CI 1-23.1) and absence of explanation about the clopidogrel importance at the time of hospital discharge (p = 0.001, OR 10.8, CI 2.7-42.9).

CONCLUSIONS

The incidence of STH at 22- month follow up in real-world patients was substantially higher than the rate reported in previous clinical trials. Subsidizing the cost of thienopyridines, providing a clear explanation to the patient and encouraging cardiology follow up may prevent premature discontinuation of thienopyridines after implantation of DES and reduce the incidence of STH after DES implantation.