Prolonged DAPT doesn’t help left main CAD

SAN DIEGO – Among patients who receive a drug-eluting stent (DES) in their left main coronary artery (LMCA), continuation of dual antiplatelet therapy (DAPT) past 1 year appears to provide no benefit.

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The results come from a subanalysis of the EXCEL trial, which compared the Xience DES to coronary artery bypass graft (CABG) surgery in LMCA lesions.

The LMCA is worrisome to a lot of physicians because of the large amount of myocardial tissue it contains, and they often prescribe DAPT past the generally recommended 1 year. “It’s this magic thing, that ‘Well, it’s left main stenting, and you’d better protect the patient.’ But it turns out that it doesn’t,” said Sorin Brener, MD, director of the catheterization lab at New York Methodist Hospital, who presented the results of the study at the Transcatheter Cardiovascular Therapeutics annual meeting.

The researchers compared patients in both groups who opted to stop DAPT after 1 year versus those who continued therapy out to 3 years, and the news was not favorable for continuation. A composite of death, myocardial infarction, or stroke was higher among patients who continued DAPT, though the results did not reach statistical significance.

It’s possible that patients who continued DAPT were more ill on average. “Obviously, there could be cases where the doctor decided they deserved more prolonged therapy, but it’s not measurable, so I don’t think they were sicker,” said Dr. Brener.

The study was also underpowered. Those worse trends probably don’t represent a real signal, according to Dr. Brener. Rather, they suggest that there is no significant difference between the approaches. “The signal just tells you that there is no difference, and that prolonging DAPT probably just induces some minor bleeding, but it doesn’t protect you. So the message would be that you should treat all your patients the same way regardless of where you put the stent,” said Dr. Brener.

The researchers compared data from 497 patients in the EXCEL trial who continued DAPT out to 3 years with that from 136 who stopped DAPT early (115 stopped in year 1-2; 21 stopped in year 2-3). The baseline characteristics of the two groups were similar except for a higher incidence of recent MI in the group that stopped DAPT early (21.3% vs. 13.7%; P = .03).

At 3 years, death, MI, or stroke occurred in 7.8% of the continuation group and in 5.2% of the patients who stopped DAPT. All-cause mortality was 5.8% in the continuation group compared with 2.3% of those who stopped. When the researchers restricted the analysis to patients who presented with acute coronary syndrome, 7.6% and 3.6%, respectively, met the primary endpoint. None of these differences reached statistical significance.

The study was limited by a high dropout rate from DAPT in the first year: 152 patients stopped taking the medication even though they experienced no events, and they were excluded from the analysis.

The EXCEL trial was funded by Abbott. Dr. Brener has been a consultant or received honoraria or speaker’s fees for AstraZeneca.

SOURCE: Brener S. TCT 2018, Abstract TCT-1.