Implantable defibrillator benefits high-risk patients after PCI for STEMI
SAN FRANCISCO — Prophylactic implantation of an implantable cardioverter defibrillator within 90 days of undergoing PCI for STEMI reduced risk for death in certain high-risk patients, according to the results of the DAPA trial.
The researchers conduced a prospective, randomized study of patients at high risk for sudden death who had PCI to treat STEMI and were assigned ICD implantation plus conventional medical therapy or conventional medical therapy alone.
“We wanted to know if early ICD implantation helped patients at high risk for mortality after primary PCI,” Danielle Haanschoten, MD, a researcher and PhD candidate at Isala Heart Center in Zwolle, the Netherlands, told Cardiology Today.
“Importantly, the DINAMIT trial on this topic in patients with acute myocardial infarction included only 25% of patients with primary PCI,” Arif Elvan, MD, PhD, director of the Research Institute at Isala Heart Center, said in an interview. “The majority of patients were treated with thrombolysis, which is an old treatment. So we included only patients with STEMI treated by primary PCI.”
Among the inclusion criteria were TIMI flow grade of less than 3 after primary PCI, left ventricular ejection fraction less than 30%, Killip class II or higher and primary ventricular fibrillation. The ICD group underwent implantation between 30 and 60 days after their PCI. The primary outcome was all-cause mortality.
After enrollment of 266 patients (mean age, 61 years; 78% men), the trial was stopped due to slow enrollment on the advice of the data safety monitoring board, Haanschoten said during a presentation at the Heart Rhythm Society Annual Scientific Sessions.
Crossover rates were 4.6% in the ICD group and 19.3% in the control group, according to the researchers.
During a median follow-up of 9 years, 24.4% of patients in the ICD group died compared with 35.6% of patients in the control group (P = .02), Haanschoten said.
“The difference was mainly driven by cardiac deaths, and the noncardiac deaths were nonsignificant,” Haanschoten told Cardiology Today. “In the previous trials, nonarrhythmic deaths were higher in the ICD groups, which completely neutralized the effect of the ICD on arrhythmic deaths.”
“The curves separate from the beginning and the difference in mortality increases over time,” Elvan said. “We think it’s important that we selected patients who were prone to arrhythmic events, rather than, for example, patients with end-stage heart failure who would die from that, as was seen in the DINAMIT study. Here, we excluded those patients.”
Sudden cardiac death was numerically lower in the ICD group (3.1% vs. 5.9%; P = .521), she said.
“Our trial was terminated prematurely because of the slow inclusion rate, and nobody was motivated to include patients in our trial after the DINAMIT trial was published,” Elvan said. “But because of the long follow-up, we reached the number of endpoints we calculated in the beginning. In the end, the trial has added value and we should consider implanting ICDs in the early phase after MI.” – by Erik Swain
Haanschoten D, et al. Abstract S-MP12-02. Presented at: Heart Rhythm Society Annual Scientific Sessions; May 8-11, 2019; San Francisco.
Disclosure: Elvan and Haanschoten report no relevant financial disclosures.