Early ICD use prolongs survival after coronary stenting
PARIS — Early use of an implantable cardioverter defibrillator after primary PCI lengthened survival among high-risk patients with STEMI, according to results of the DAPA trial reported at the European Society of Cardiology Congress.
DAPA, which was stopped prematurely in 2013 due to slow enrollment, examined whether ICD implantation between 30 and 60 days after primary PCI for STEMI would provide survival benefit among patients at high risk for death.
Before trial termination, 266 patients were randomly assigned to prophylactic ICD implantation or optimal medical therapy only and were followed up for a median of 9 years.
In the intention-to-treat analysis of the primary endpoint — all-cause mortality after 3 years of follow-up — the mortality rate was significantly lower in the ICD group, at 24.4% vs. 35.5% (HR = 0.58; 95% CI, 0.37-0.91), Danielle Haanschoten, MD, researcher at Isala Heart Center in Zwolle, the Netherlands, said here.
The mortality difference between groups was mainly driven by cardiac death, according to Haanschoten. The cardiac death rate was 11.4% in the ICD group vs. 18.5% in the optimal medical therapy group (HR = 0.52; 95% CI, 0.28-0.99). Among those who died of cardiac death, most died of HF, she said.
Rates of noncardiac death and sudden cardiac death were not significantly different between the two groups, according to results presented.
Reassessment of left ventricular ejection fraction at 18 months showed that LVEF was improved in 46% of patients overall, unchanged in another 46% and worsened in 8%.
“Randomization to ICD was associated with significant lower total and cardiac mortality rates in this selected population. Despite LVEF improvement in 46% of the study population, the benefit of ICD remained preserved due to the long-term follow-up of 9 years,” Haanschoten said during the presentation.
However, “premature termination of the trial and a lack of ICD therapy data limits interpretation of these results,” she said. “But the data do suggest that we might need more sophisticated risk stratification tools to identify patients at high risk of sudden cardiac death early after STEMI.”
The multicenter, randomized controlled trial was conducted at 12 hospitals in the Netherlands and Poland. The trial enrolled patients with STEMI treated with primary PCI who had at least one high risk factor, including LVEF less than 30% within 4 days, TIMI flow less than 3 after primary PCI, primary ventricular fibrillation (> 24 hours) and/or Killip class of at least 2. ICD was programmed with a shock-only protocol (> 190 beats per minute). The mean age at baseline was 60 years and three-quarters were men. Most had very large anterior infarctions. The rate of crossover from the control to ICD group was 20%.
The role of ICD implantation in primary prevention in patients after MI remains challenging, Christophe Leclercq, MD, PhD, from the department of cardiology, Centre Cardio-Pneumologique, Rennes, France, said during a discussion of the trial.
“When you discuss ICDs in post-MI patients for primary prevention of sudden cardiac death, you have to answer two questions. The first question is: What is the real benefit of ICD in this population in 2019? The other question is: When do we have to implant an ICD after MI?” he said.
However, DAPA was “not able to answer these very interesting questions,” due to limitations such as its initiation 16 years ago, its premature termination, changes in the definition of “high risk” over time, “old fashioned” ICD programming and a lack of data about shocks.
“It’s time to revisit the benefit of ICD in post-MI patients,” Leclercq said.
Leclercq said efforts are underway with PROFID, a huge project that is looking at implementation of personalized risk prediction and prevention of sudden cardiac death after MI. Data from 1 million patients will be used to calculate a risk score to predict sudden cardiac death in this population, he said. The risk score will be evaluated in two randomized trials; one trial in patients with low EF and low risk for sudden cardiac death and the other in patients with intermediate EF and high risk for sudden cardiac death.
Haanschoten also echoed the need for additional investigation.
“Further research with a DAPA-like trial is necessary to confirm these results and also evaluate ICD benefit in the era of primary PCI,” she said. – by Katie Kalvaitis
Haanschoten D, et al. Hot Line Session 6. Presented at: European Society of Cardiology Congress; Aug. 31-Sept. 4, 2019; Paris.
Disclosures: The study was sponsored by Medtronic. Haanschoten reports no relevant financial disclosures. Leclercq reports financial ties with Abbott, Biotronik, Boston Scientific, Microport and Medtronic.