Short-term DAPT Not Necessarily the Best Option for All, Especially After Complex PCI

Much of the conversation around individualizing decisions on dual antiplatelet therapy (DAPT) duration after PCI has focused on clinical parameters, but a new study presented Monday at the European Society of Cardiology (ESC) Congress 2016 advocates integrating anatomical factors in order to more precisely prevent adverse outcomes.

Earlier this year, the American College of Cardiology (ACC) and American Heart Association (AHA) released a focused update on guidelines for DAPT duration based on results from the DAPT Study and PEGASUS TIMI 54. The document, published in the September 6, 2016, issue of the Journal of the American College of Cardiology, primarily shortened the length of treatment from 12 to 6 months for the majority of patients, but it also included caveats allowing for even shorter or perhaps longer treatment for those with differing ischemic and bleeding risks based on clinician judgement.

Additionally, the DAPT Score was introduced last year with the goal of singling out patients who may or may not benefit from extended thienopyridine therapy. To calculate this score, clinicians use the following: patient age, diabetes status, smoking habits, PCI or MI history, presence of chronic heart failure or LVEF > 30%, and index procedural characteristics including MI at presentation, vein-graft PCI, and stent diameter.

However, Gennaro Giustino, MD (Icahn School of Medicine at Mount Sinai, New York), and colleagues used a different methodology to evaluate the efficacy and safety of short-term (3 or 6 months) or long-term (at least 12 months) dual antiplatelet therapy after PCI. The results released at the ESC Congress were simultaneously published online in the Journal of the American College of Cardiology.

Stratifying 9,577 patients from six randomized trials by whether or not they had complex PCI—defined as three vessels treated, at least three stents implanted, at least three lesions treated, bifurcation with two stents implanted, total stent length > 60 mm, or chronic total occlusion—the researchers followed the population for a median of 392 days. Overall, the 17.5% of patients who underwent complex PCI had a higher risk of MACE (adjusted HR 1.98; 95% CI 1.50-2.60) than those who had more straightforward procedures.

But compared with short-term DAPT, long-term treatment resulted in greater MACE reductions in the complex PCI group (adjusted HR 0.56; 95% CI 0.35-0.89) compared with the noncomplex PCI arm, in which there was no significant difference between the two durations (adjusted HR 1.01; 95% CI 0.75-1.35; P for interaction = 0.01). Additionally, long-term DAPT had a greater protective effect as patient procedural complexity increased.

However, long-term DAPT was associated with a higher risk of major bleeding—consistent with prior research—regardless of procedural complexity.

Giving Objectivity to Intuition

In an interview with TCTMD, Eric Bates, MD (University of Michigan, Ann Arbor), who served on the writing committee for the ACC/AHA focused update but did not participate in this study, said the findings support using anatomical factors as “a better surrogate for risk stratification than some of the clinical items we use like diabetes and hypertension.

“You can have the clinical risk factors but have a low disease burden, and you can control the risk factors with drugs that are targeted, but atherosclerosis in many ways is an anatomic disease,” he explained. “By using an anatomic risk-stratification scheme, . . . it sounds like they’ve been more successful in identifying a high-risk population where the risk-benefit ratio favors longer-duration therapy.”

Bates noted that some authors of this paper had previously co-authored studies supporting shorter duration therapy, which makes the results of this one “even more interesting and less ideological.” Clinical interventionalists are already stratifying their patients by anatomy, albeit instinctively, Bates said.

“It’s not one-size-fits-all obviously,” he observed. But “these authors have given us some objectivity to what previously has been an intuitive, emotional response. . . . This would give some scientific credence to individual decision-making along those lines.”

In the past few years, it’s possible that patients who would benefit the most from longer-term DAPT “could have gotten lost in the enthusiasm for treating with shorter-duration therapy,” Bates commented. With the field of interventional cardiology moving forward, physicians need to understand that while many patients can benefit from breakthrough therapies or updated processes, “we can’t forget that there are some really important subgroups that need to be treated differently, . . . and we can’t apply new exciting findings to every patient we treat,” he said.

“I think this study very carefully brings the pendulum back into balance and points out that yes we can go shorter with dual antiplatelet therapy in lots of patients with these newer generation stents, and that’s great, but there are some patients that still need longer duration dual antiplatelet therapy and this study gives us a nice anatomic outline on who those patients might be,” Bates commented.

But it is important for physicians to revisit this decision during each visit with a patient after complex PCI, he advocated.

“You may decide to go shorter if they are having bleeding problems or having trouble paying therapy. You may decide to go for longer if they are tolerating therapy well and you’re worried about their risk factor control success and about the complexity of anatomy you decided to treat with PCI instead of with CABG,” Bates concluded.

Note: Several co-authors of this paper are faculty members of the Cardiovascular Research Foundation, the publisher of TCTMD.