The rate of patients who discontinue antiplatelet therapy is high, particularly in the first year after a drug-eluting stent (DES) implantation, consequently leading to an increase in cardiovascular events, according to a study published in the Jan. 15 issue of the American Journal of Cardiology.
Because data outlining the long-term rates of the discontinuation of antiplatelet therapy after a DES implantation is sparse, Roberta Rossini, MD, PhD, of the Ospedali Riuniti di Bergamo in Bergamo, Italy, and colleagues assessed the prevalence and predictors of premature discontinuation of oral antiplatelet therapy to evaluate long-term effects in 1,379 patients who underwent PCI between June 2005 and March 2008 at two institutions in northern Italy.
The researchers followed patients for 36 months and assessed the discontinuation of both aspirin and clopidogrel (Plavix, Bristol-Myers Squibb/Sanofi-Aventis), and reported major adverse cardiac events (MACE), stent thrombosis and major and minor bleeding events.
Rossini and colleagues reported that 8.8 percent of the 1,358 patients discontinued one or both antiplatelet agents early (less than 12 months after discharge) and 4.8 percent discontinued therapy late (greater than 12 months).
“We found that one out of 10 patients discontinued aspirin and/or clopidogrel,” Rossini told Cardiovascular Business News.
Rossini said that the majority of the patients who prematurely withdrew from antiplatelet therapy did so as a result of medical advice, either due to the fact that they were undergoing surgery or dental procedures or because they experienced a bleeding event.
The researchers reported that early discontinuation could be predicted by in-hospital major bleeding, use of anticoagulants at discharge and a lack of a statin prescription. “This might identify patients with a lower compliance to medical therapy,” Rossini offered.
A previous stoke event was the sole independent predictor of late discontinuation.
The researchers found that patients who discontinued antiplatelets early experienced a greater number of MACE compared with those who did not, 28.6 versus 4.7 percent. The overall incidence rates of MACE and stent thrombosis were 14.9 and 3.8 percent, respectively. The rate of cardiac death also was higher for those who discontinued their therapy: 5 versus 1.2 percent, and the rate of overall mortality was 13.4 versus 4.7 percent, respectively.
Stent thrombosis occurred in 7.6 percent of the patients who discontinued antiplatelet therapy early and 3.4 percent who stayed on the regiment.
Rossini said, “We should cooperate with doctors of other fields, stressing the importance of maintaining the antiplatelet therapy after drug-eluting stent implantation.
“In the future, more and more patients with coronary drug-eluting stents will require surgical interventions,” said Rossini. Due to this increase, careful patient selection will be necessary before implanting DES. For patients who are likely to prematurely withdraw from taking antiplatelet therapy—those at a high risk of bleeding or with comorobidities requiring surgery—should be implanted with a bare-metal stent instead.
“Alternatively a conservative therapy or surgical revascularization should be considered,” she said.
In conclusion, Rossini said, “We should explain to patients that PCI will not necessarily be the end of all the problems, but it will require long-term regular medication.”