Reply
Renata Rogacka, MD,
Alaide Chieffo, MD,
Antonio Colombo, MD*
We thank Drs. Ruiz-Nodar, Marìn, Lip, Giuliano, and Lotfi for their interest in our work (1). Our study was conceived to approach the growing problem of patients necessitating chronic anticoagulation who undergo percutaneous coronary intervention (PCI) procedures with stent implantation. We retrospectively analyzed our computer database, retrieved the data of the patients, and contacted the patients. Of course, we agree with Dr. Ruiz-Nodar and colleagues that the major limitation of the study is the small number of the patients (n = 127) analyzed and its retrospective character. Because of the heterogeneity of the patients on chronic anticoagulation, the elevated risk of thromboembolic events for the majority of pathologies that require this type of treatment, and the well-documented risk of stent thrombosis if a dual antiplatelet regiment is not observed, the randomization may be particularly difficult, if not impossible.
We read carefully the study of Ruiz-Nodar et al. (2), which is the largest published study examining the problem of the antiplatelet and anticoagulation regimen in patients with atrial fibrillation (AF). The differences in the outcome between this article and our study (major adverse cardiovascular events 32.3% vs. 23.6% and major bleeding 12.3% vs. 3.7%, respectively) probably derive from the fact that we analyzed various subgroups of patients who need chronic anticoagulation (AF, valve prostheses, left ventricle thrombus, and venous and pulmonary embolism being the most frequent indications) with obvious differences in the thromboembolic and bleeding risk among them. Ruiz-Nodar et al. (2) state that AF patients represent a high-risk group of patients. The risk of thromboembolic events in AF patients is most commonly measured with a Congestive heart failure, Hypertension, Age, Diabetes, Stroke-2 points score (CHADS2) (the score used in both articles). The adjusted stroke rate in the patients with the maximum CHADS2 (= 6) is very high: 18.2% (10.5 to 27.4) (3). However, this risk is even higher in patients with mechanical valve prostheses, depending on the valve type and position. According to Ansell et al. (4), Douketis et al. (5) and Jafri et al. (6), it varies from 10% to 91% in the absence of oral anticoagulation.
The majority of patients in our study were treated electively (47.2%) with a relatively low incidence of acute coronary syndromes (25.9%) as an indication for the percutaneous coronary intervention. We agree with Dr. Ruiz-Nodar and colleagues' comment that this may have influenced the lower incidence of major adverse cardiovascular events.
The follow-up was carefully conducted in all of our patients, especially during the period of triple therapy. The mean follow-up time was 21 ± 19.8 months. The high standard deviation derives from the wide variety of the follow-up length among the patients (included in the study from February 1999 to December 2006). We tried to present the exact characteristics of the patients in whom bleeding occurred, with major interest put on the time from the start of the triple therapy to bleeding. Addressing the point raised by Drs. Giuliano and Lotfi, none of the patients who survived bleeding events had a recurrence. The 3 patients who suffered gastrointestinal hemorrhage (2 major and 1 minor bleeding) were carefully monitored after the adverse event. The small number of patients exposed to the risk of recurrence and the fact that in 2 of them oral anticoagulation was temporarily stopped after the bleeding event does not permit us to draw any conclusion in this area.
The recent American College of Cardiology/American Heart Association guidelines (7) recommend a period of 12 months of dual antiplatelet therapy after drug-eluting stent (DES) implantation. In our study, the patients analyzed had been treated with DES implantation since April 2002. In the initial period, dual antiplatelet therapy duration varied from 3 to 6 months. This fact influenced the mean duration of the triple therapy treatment in our report (7.7 ± 3.6 months after DES implantation). We agree with Drs. Giuliano and Lotfi that the risk of recurrent bleeding events may be increased the longer the triple therapy period, even if there are no published data concerning this problem. The evaluation of the risk of restenosis, major bleeding, and stent thrombosis (9% to 45% mortality) (8,9) needs to be performed individually. In our study, the comparison of bleeding events and mortality between DES and bare-metal stents did not yield any significant value (there was only a significant difference in target vessel revascularization in favor of DES, 14.1% vs. 26.8%). The small number of patients and events are the likely explanation. Presently, we prefer to treat with bare-metal stents those patients with a high thromboembolic risk, reducing the triple therapy period to 1 month, whereas DES implantation is considered in patients at low risk in whom oral anticoagulation may be temporarily interrupted; lesion and other patient characteristics are also taken into account.
In conclusion, we underline the fact that the antiplatelet/anticoagulant regimen should be established individually, on the basis of patient characteristics (risk factors for thromboembolism/stent thrombosis, bleeding, and restenosis) and the type of lesion to be stented. Further studies on larger populations and with longer follow-up will be necessary to establish the optimal treatment in these patients.
* Emo Centro Cuore Columbus, Via Buonarotti 48, 20145 Milano, Italy (Email: colombo{at}emocolumbus.it).
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Dual Antiplatelet Therapy Plus Oral Anticoagulation: How Does Hemorrhagic Risk Impact Stent Selection?
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J. Am. Coll. Cardiol. Intv. 2008 1: 330.
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