Longer DAPT Duration Reduces Adverse Events After PCI for In-Stent Restenosis

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Patients who undergo percutaneous coronary intervention (PCI) to treat in-stent restenosis experience fewer major adverse events at 2 years if they remain on dual antiplatelet therapy (DAPT) for 24 months rather than stopping at 6 months. Moreover, there is no difference in bleeding between the durations, according to findings published online October 23, 2013, ahead of print in the Journal of the American College of Cardiology.

In the overall PRODIGY (Prolonging Dual-Antiplatelet Treatment after Grading Stent-induced Intimal Hyperplasia) trial, published in Circulation in 2012, extending DAPT from 6 to 24 months after stenting in patients with stable CAD or ACS not only failed to reduce thrombotic events but doubled the risk of major bleeding.

The current analysis, conducted by Gianluca Campo, MD, of Azienda Ospedaliera Universitaria Sant’Anna (Ferrara, Italy), and colleagues, looked at the 224 patients (11.4% of the entire PRODIGY cohort) treated with DES for angiographically documented in-stent restenosis either at the time of inclusion (n = 96) or later during the course of the study (n = 128). Based on their original randomized treatment assignment, patients were prescribed 6 months (n = 114) or 24 months (n = 110) of DAPT after the restenosis-related procedure.

No Effect on Bleeding

Baseline characteristics were similar between the 2 DAPT durations. Treatment compliance was high, with 95% and 98% of patients on the short- and long-term regimens adhering to DAPT at 6 months. After 18 months, DAPT use was 2% and 96%, respectively (P < 0.01).

At 2 years after PCI, the combined rate of death, nonfatal MI, or cerebrovascular events (primary endpoint) was more than doubled in patients on the 6-month regimen, a difference driven primary by death and MI. Though statistically similar, the rate of definite/probable stent thrombosis was numerically higher with the shorter duration of DAPT. Bleeding complications, including TIMI major and minor bleeding, were similar between the 6- and 24-month groups (table 1).

Table 1. Two-Year Outcomes by DAPT Duration

 

6 Months
(n = 114)

24 Months
(n = 110)

P Value

Death, Nonfatal MI, Cerebrovascular Events

16.7%

7.3%

0.034

Death

10.5%

3.5%

0.04

Nonfatal MI

8%

3%

0.07

Cerebrovascular Events

1%

2%

0.4

Definite/Probable Stent Thrombosis

2.5%

0

0.1

TIMI Bleeding
Major
Minor


 0
2%


 1%
1%

 
0.5
0.7


In an e-mail communication with TCTMD, Dr. Campo reported that in-stent restenosis is “more frequent in patients with severe calcification, bifurcation lesions, and longer and/or smaller stents. In these patients, stent expansion is more difficult and stent malapposition is more frequent.”

All of these factors increase the risk of thrombotic events, raising the potential for benefit from a more aggressive antiplatelet regimen, he commented.

It is difficult to explain the lack of effect on bleeding, Dr. Campo added, speculating that the presence of comorbidities and other risk factors in this population may be accompanied by higher on-treatment platelet reactivity. Such reactivity “may explain both the higher incidence of ischemic events and lower incidence of bleeding,” he noted.

For Now, Evidence Is Preliminary

Currently, Dr. Campo said, there is no consensus on the ideal DAPT duration for patients with in-stent restenosis. The majority of affected patients receive DES and, as such, current guidelines recommending 12 months of DAPT would apply. “Ours is the first evidence suggesting a longer DAPT regimen,” he noted.

The PRODIGY researchers caution in the paper that the evidence is “preliminary” and that additional study is required to know whether “administration of ticagrelor or prasugrel will be associated with the same or better results.”

Deepak L. Bhatt, MD, MPH, of Brigham and Women’s Hospital (Boston, MA), told TCTMD in an e-mail communication, “This is a well done study with provocative findings. The PRODIGY investigators have identified a subgroup of patients, those undergoing PCI for restenosis, who appear to benefit from prolonged dual antiplatelet therapy. This finding makes intuitive sense, and some interventionalists already practice in this manner. However, given the modest size of this substudy, ideally the results should be confirmed in another, larger study.”

 


Source:
Campo G, Tebaldi M, Vranckx P, et al. Short vs. long-term duration of dual antiplatelet therapy in patients treated for in-stent restenosis: A PRODIGY trial substudy. J Am Coll Cardiol. 2013;Epub ahead of print.

 

 

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Disclosures
  • Dr. Campo reports no relevant conflicts of interest.
  • Dr. Bhatt reports relationships with multiple device and pharmaceutical companies.

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