Study details death risks associated with long-term antiplatelet therapy

March 15, 2017

A study by a multi-institutional research team has tracked the long-term incidence of death following ischemic and bleeding events occurring in patients more than one year after placement of a coronary stent. Their study appearing in the current issue of JAMA Cardiology found that ischemic events - those caused by a blockage in blood flow to the heart or brain - occurred more frequently than bleeding events in the 12 to 33 months after stenting and that both types of events incurred a serious mortality risk.

"We know from previous trials that continuing dual antiplatelet therapy longer than 12 months after coronary stenting is associated with both decreased ischemia and increased bleeding risk, so these findings reinforce the need to identify individuals who are likely to experience more benefit than harm from continued dual antiplatelet therapy," says lead author Eric Secemsky, MD, MSc, a fellow in the Massachusetts General Hospital Division of Cardiology.

Patients who received stenting or other procedures designed to open clogged coronary arteries are at a persistent risk of recurrent ischemia, either through progression of their underlying cardiovascular disease or clotting that develops within the stent. The use of aspirin and other antiplatelet drugs to prevent these processes in the first year after stenting has become standard practice, but recent trials have shown that -despite continued reduction in recurrent ischemia - dual antiplatelet therapy is also associated with an increased risk of bleeding when treatment is continued longer than one year.

The current study is an analysis of data collected in the Dual Antiplatelet Therapy (DAPT) Study, an international, multicenter trial designed to determine the benefits and risks of continuing dual antiplatelet therapy for more than a year. More than 25,600 enrolled patients received both aspirin and a thienopyridine antiplatelet drug (clopidogrel or prasugrel) for one year after stenting. Participants who had followed the study protocol and had no serious cardiovascular or bleeding events during that first year were then randomized to either continue with dual therapy or to receive aspirin plus a placebo for another 18 months.

The overall findings of the DAPT study were that, compared with switching to aspirin only after one year, continuing dual antiplatelet therapy for a total of 30 months led to a 1.6 percent reduction in major adverse cardiovascular and cerebrovascular events - a composite of death, heart attacks, clots developing within the stent and strokes - and a 0.9 percent increase in moderate to severe bleeding events, a few of which involved bleeding around or within the brain. The current study was designed to investigate how often patients died after either ischemic or bleeding events and how long the risk of death persisted after such events.

During the 21-month study period, 11 percent of the 478 individuals who experienced an ischemic event died, representing a 0.5 percent incidence of death following such events among the more than 11,600 DAPT participants randomized at the end of the first year. Among the 232 participants who experienced a bleeding event, 18 percent died, although the higher death rate among those with bleeding events was somewhat offset by the smaller incidence of such events. The cumulative incidence of death following a bleeding event was 0.3 percent among all randomized participants

Deaths following bleeding events primarily took place within 30 days of the event; and while deaths after ischemic stroke or clotting within the stent usually took place soon after the event, the increased risk of death from a heart attack persisted during the rest of the study period. Overall, having either type of event resulted in a serious - an 18-fold increase after any bleeding event and a 13-fold increase after any ischemic event.

"Since our analysis found that the development of both ischemic and bleeding events portend a particularly poor overall prognosis, we conclude that we must be thoughtful when prescribing any treatment, such as dual antiplatelet therapy, that may include bleeding risk," says Secemsky. "In order to understand the implications of therapies that have potentially conflicting effects - such as decreasing ischemic risk while increasing bleeding risk - we must understand the prognostic factors related to these events. Our efforts now need to be focused on individualizing treatment and indentifying those who are at the greatest risk of developing recurrent ischemia and at the lowest risk of developing a bleed."

In a previous study, Secemsky and his co-authors developed a risk score using DAPT data that, based on readily available factors - such as patients' age, smoking history, presence of diabetes, and details of cardiac disease and treatment - can help determine whether or not dual antiplatelet therapy should continue past the one-year mark. The risk score tool has recently been included in American College of Cardiology(ACC)/American Heart Association guidelines on the duration of dual antiplatelet , and is available on the ACC website.

Explore further: DAPT score improves risk prediction of continued DAPT

More information: JAMA Cardiology, DOI: 10.1001/jamacardio.2017.0063

Related Stories

DAPT score improves risk prediction of continued DAPT

June 1, 2016
(HealthDay)—A decision tool (dual antiplatelet therapy [DAPT] score) improves risk prediction for continued DAPT beyond assessment of myocardial infarction (MI) history, according to a study published in the May 31 issue ...

Guidelines updated on duration of dual antiplatelet Tx in CAD

March 31, 2016
(HealthDay)—The American College of Cardiology and the American Heart Association Task Force on Clinical Practice Guidelines has updated the recommendations regarding duration of dual antiplatelet therapy (DAPT) for patients ...

Peripheral arterial disease: Longer duration of dual antiplatelet therapy after stent placement improves outcomes

August 30, 2016
In a study published online by JAMA Cardiology, Marco Valgimigli, M.D., Ph.D., of Bern University Hospital, Bern, Switzerland, and colleagues assessed the efficacy and safety of prolonged (24 months) vs short (6 months or ...

Duration of antiplatelet therapy following PCI, risk of adverse events

March 17, 2015
An additional 18 months of dual antiplatelet therapy among patients who received a bare metal coronary stent did not result in significant differences in rates of stent thrombosis (formation of a blood clot), major adverse ...

Results suggest extending post-stenting DAPT beyond one year

September 1, 2015
Extending clot-preventing dual antiplatelet therapy (DAPT) beyond the recommended 12 months after coronary stenting "should be considered" in patients at low risk for bleeding, investigators for the OPTIDUAL trial recommend.

Dual antiplatelet Tx similar to aspirin post-CABG in diabetes

January 10, 2017
(HealthDay)—For post-coronary artery bypass grafting (CABG) patients with diabetes, cardiovascular and bleeding outcomes do not differ significantly with use of dual antiplatelet therapy (DAPT) versus aspirin, according ...

Recommended for you

Researchers investigate the potential of spider silk protein for engineering artificial heart

August 18, 2017
Ever more people are suffering from cardiac insufficiency, despite significant advances in preventing and minimising damage to the heart. The main cause of reduced cardiac functionality lies in the irreversible loss of cardiac ...

Lasers used to detect risk of heart attack and stroke

August 18, 2017
Patients at risk of heart attacks and strokes may be spotted earlier thanks to a diagnosis tool that uses near-infrared light to identify high-risk arterial plaques, according to research carried out at WMG, University of ...

Cholesterol crystals are sure sign a heart attack may loom

August 17, 2017
A new Michigan State University study on 240 emergency room patients shows just how much of a role a person's cholesterol plays, when in a crystallized state, during a heart attack.

How Gata4 helps mend a broken heart

August 15, 2017
During a heart attack, blood stops flowing into the heart; starved for oxygen, part of the heart muscle dies. The heart muscle does not regenerate; instead it replaces dead tissue with scars made of cells called fibroblasts ...

Injectable tissue patch could help repair damaged organs

August 14, 2017
A team of U of T Engineering researchers is mending broken hearts with an expanding tissue bandage a little smaller than a postage stamp.

'Fat but fit' are at increased risk of heart disease

August 14, 2017
Carrying extra weight could raise your risk of heart attack by more than a quarter, even if you are otherwise healthy.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.