DAPT Cessation Within 1 Year Increased Risk for Major Adverse Events

MIAMI BEACH, FLA.—Patients who stopped dual antiplatelet therapy within 1 year following PCI are at increased risk for major adverse events, according to results from the real-world PARIS registry.

In over 5,000 patients who received stent implantation, cessation of dual antiplatelet therapy (DAPT) was associated with higher incidence of spontaneous MI (4.8% vs. 1.4%), major bleeding (9% vs. 1%) and MACE (11% vs. 6.5%; P<.001 for all).

The increased risk — which was strongest in the first 7 days after cessation and subsided after 30 days — was attributable entirely to non-adherence, Roxana Mehran, MD, of Mount Sinai School of Medicine, New York, said in a presentation at TCT 2012.

Physician-guided discontinuation—as opposed to other modes of cessation—did not increase adverse events.

DAPT cessation was defined as discontinuation (physician-guided), interruption (temporary, voluntary or physician guided), and disruption (due to bleeding, voluntary non-adherence). “These results suggest that the risk associated with DAPT cessation after PCI is not uniform, but rather varies by the underlying mode, a novel finding that might influence the practice patterns and risk assessment in post-PCI patients stopping DAPT,” Mehran said (see Figure).

The American College of Cardiology and American Heart Association guidelines recommend 30-day DAPT for patients who receive a bare-metal stent, 1 year for patients who receive a DES, and 1 year for patients with ACS regardless of stent type.

Despite those guidelines, researchers have not determined a precise optimal duration for DAPT, Mehran said. Also, the question of whether risk associated with DAPT cessation varies by underlying mode had not been prospectively examined.

PARIS, a multinational, observational study, included 5,033 patients from 15 centers in five countries who were followed for 2 years after stent implantation. Patients with both BMS and DES were included in the study and a blinded external committee adjudicated all events.

At 1 year, 1,004 patients had stopped DAPT. Of those, 620 (61.7%) were classified as non-adherent by pre-specified study criteria.

Researchers used Cox proportional hazard regression models with DAPT cessation and non-adherence entered as time-varying covariates. They generated additional covariates to assess the impact of DAPT cessation at three time points: 0 to 7 days, 8 to 30 days, and beyond 30 days.

Study results showed DAPT disruption and interruption were significantly associated with risk of death and spontaneous MI at all time points (P<.001 for both). They also were associated with increased risk of definite/probable stent thrombosis and MACE, particularly in the first 7 days after cessation (P<.001 for both).