Meta-analysis: Abbreviated DAPT after PCI may be considered for older adults

Older adults who have undergone percutaneous coronary intervention (PCI) may do well with a shortened dual antiplatelet therapy (DAPT) duration, which has been shown to reduce the risk of bleeding without increasing the risk of adverse clinical events in a network meta-analysis.

According to pooled data from 14 randomized clinical trials, DAPT durations of 1, 3, 6, and 12 months did not significantly differ in terms of the primary outcome of net adverse clinical events (NACE) (1 vs 12 months: risk ratio [RR], 0.60, 95 percent confidence interval [CI], 0.33–1.07; 3 vs 12 months: RR, 0.77, 95 percent CI, 0.52–1.15; 6 vs 12 months: RR, 0.76, 95 percent CI, 0.49–1.17). [JAMA Netw Open 2024;7:e244000]

The same was true for major adverse cardiovascular events (MACE) (1 vs 12 months: RR, 0.79, 95 percent CI, 0.61–1.01; 3 vs 12 months: RR, 0.94, 95 percent CI, 0.73–1.20; 6 vs 12 months: RR, 0.89, 95 percent CI, 0.70–1.13).

However, the risk of bleeding was up to 50-percent lower with 3 months of DAPT than with longer DAPT durations (vs 6 months: RR, 0.50, 95 percent CI, 0.29–0.84; vs 12 months: RR, 0.57, 95 percent CI, 0.45–0.71). Likewise, 1 month of DAPT was associated with a 32-percent lower risk of bleeding compared with 6 months of DAPT (RR, 0.68, 95 percent CI, 0.54–0.86).

The lower risk of bleeding with an abbreviated DAPT duration of 1 or 3 months was observed “despite a higher risk of complex coronary anatomy and increased calcification, comorbidities, and vascular tortuosity among older adults—features that traditionally make clinicians wary of abbreviating DAPT,” the investigators said. [JACC Adv 2023;2:100389]

“This study, which represents the first network meta-analysis of this shortened treatment for older adults, suggests that clinicians may consider abbreviating DAPT for older adults,” they added.

Risk-benefit balance

To date, there are no age-specific recommendations for the duration of DAPT after a PCI. As much as defining the optimal DAPT duration for older adults is crucial given their heightened susceptibility to both ischaemic events and bleeding events, this goal presents a unique challenge because of the competing pathophysiological processes in older adults, according to the investigators.

For the most part, ageing disrupts all three components of Virchow’s triad, owing to progressive loss of venous structural integrity, endothelial dysfunction, alterations in the microcirculation, and an upregulation of procoagulant factors, thrombin, von Willebrand factor, and d-dimer. This disruption contributes to a procoagulant state, the investigators noted. [Curr Anesthesiol Rep 2021;11:387-395; Semin Thromb Hemost 2014;40:621-633]

Also, at old age, reductions in platelet count, platelet turnover, and platelet function occur, leading to an increased risk of bleeding events. This risk is even greater for older adults who have frailty and low body weight, both of which potentially influence the response to standard antiplatelet and anticoagulant medications, as the investigators pointed out.

“When considering these competing pathophysiological processes in older adults, it is especially important to clarify the tradeoffs associated with each duration of DAPT… Within that context, our results suggest that the risk-benefit balance appears to weigh in favour of abbreviating the duration of DAPT whenever feasible to reduce the risk of bleeding,” they continued.

Comprehensive evaluation

In the network meta-analysis, a total of 19,102 older adults enrolled across 14 trials comprised the overall population. The proportion of patients with acute coronary syndrome (ACS) ranged from 38.2 percent to 100 percent. Among these patients with ACS, about 61.4 percent underwent a PCI. Older adults were characterized as age >75 years in one trial, >65 years in two trials, and ≥65 years in seven trials.

“Our study further adds novelty because it is a network meta-analysis, which allows for the estimation of relative treatment effects of multiple DAPT durations that have not been directly compared head to head in individual trials, in contrast to a conventional meta-analysis approach, whereby DAPT duration of 1 or 3 months would be analysed as a homogenous intervention and DAPT duration of 6 or 12 months would be analysed as a homogenous intervention,” the investigators explained.

Meanwhile, the optimal choice of subsequent single antiplatelet therapy remains a matter of debate, they added. “Further studies will be required to confirm the optimal SAPT for older adults.”