Implantation of the Impella CP micro-axial flow pump after a heart attack significantly increased survival rates at 6 months in people suffering cardiogenic shock, the DanGer Shock Trial concludes. The study, which was presented at the American College of Cardiology (ACC) Scientific Sessions 2024 in Atlanta, found that among the 355 patients enrolled, death from any cause occurred in 82 of 179 patients (45.8%) in the microaxial-flow-pump group at six months after randomization. Death from any cause occurred in 103 of 176 patients (58.5%) in the standard-care group (hazard ratio [HR], 0.74; 95% confidence interval [CI], 0.55 to 0.99; P=0.04) at 6 months after randomization. The Abiomed/Johnson & Johnson-funded study also noted a 13-percentage-point absolute reduction in the rate of death--the study’s primary endpoint--in favor of the Impella CP (Abiomed). “This is the first time in a very long time that we have a positive study for managing cardiogenic shock,” said Jacob E. Møller, MD, PhD, DMSc, the study’s lead author, who was presenting at a Late-Breaking Clinical Trials session. “I think this will be a routine device that will be used in these desperately ill patients,” he added. Safety endpoint The investigation, which was simultaneously published online in the New England Journal of Medicine, also found that a composite safety end-point event occurred in 43 patients (24.0%) in the microaxialflow-pump group and in 11 (6.2%) in the standard-care group (relative risk, 4.74; 95% CI, 2.36 to 9.55). Renal-replacement therapy was administered to 75 patients (41.9%) in the microaxial-flow-pump group and to 47 patients (26.7%) in the standard-care group (relative risk, 1.98; 95% CI, 1.27 to 3.09). “What was a surprise for us was that the benefit seems to persist beyond 30 days,” said Møller, who is a professor in the Department of Cardiology at the Odense University Hospital in Denmark, in a news release. “It’s not only that we are saving lives, it looks like we are also saving myocardium, so the patients keep surviving, and the survival curves continue to separate beyond the first 30 days.” He added that use of Impella does not come without a cost, with significantly more serious complications in the Impella-treated patients. Overall, said Møller, there are more complications with the device as compared to standard care alone, but lives are also saved. Findings not generalizable The authors of the study, which was also funded by the Danish Heart Foundation, went on to say that the findings were not generalizable to all cases of cardiogenic shock. This was because the trial was more selective than previous trials in identifying patients who were most likely to be able to benefit from the use of a heart pump, for example, by excluding those with a risk of brain damage. However, within this patient population, the authors said the results were likely translatable beyond northern Europe to large centers with the necessary expertise to employ the device. In subgroup analyses, the authors also suggested that patients with very low blood pressure and those with lesions in more than one coronary artery could see a greater benefit from the Impella pump. “Further studies are needed to assess the benefits in more diverse patient populations and to examine how the duration of mechanical support might affect the rate of severe complications and identify opportunities to further optimize practices to minimize complications,” said Møller. ‘Persistence and progress’ In an accompanying editorial, Sunil V. Rao, MD, of NYU-Langone Health System, New York, noted several interesting aspects of the trial. First, it took 10 years to enroll 360 patients in the trial, which Rao said was a testament to the “patience and persistence of the investigators who continued the trial despite a substantial increase in the adoption of the microaxial flow pump into clinical practice without a solid evidence base to justify its use.” Second, the results of DanGer Shock contrast with several previous trials, which could be attributed to the different eligibility criteria in the current study. Third, he focused on the increase in complications in the Impella CP group as compared to the standard-of-care group, which Rao said “underscores the importance of strategies such as ultrasound-guided vascular access to reduce bleeding at the femoral access site and the use of antegrade catheters in the ipsilateral limb to maintain distal perfusion when the microaxial flow pump device is placed.” Rao concluded that several outstanding questions remain after DanGer Shock, including when the microaxial flow pump should be placed, the standardization of a shock protocol and the potential combined use of Impella with venoarterial extracorporeal membrane oxygenation, which he noted will be partially addressed in the ongoing RECOVER trial. “Until these data become available, the DanGer Shock trial is evidence of progress in the treatment of patients with AMI-CS whose peripheral vessels are able to accommodate the microaxial flow pump in the context of safe vascular access and closure and standardized weaning and removal protocols,” he wrote. Study methodology The international, multicenter, randomized trial enrolled 360 patients treated for ST segment elevation myocardial infarction (STEMI) with cardiogenic shock at 14 centers in Denmark, Germany and the United Kingdom. The median age of the patients was 67 years, and 79.0% were men. Researchers randomly assigned patients to receive standard care or standard care plus treatment with an Impella CP pump. Participants were randomized before, during or up to 12 hours after receiving treatment in the cardiac catheterization laboratory, depending on when cardiogenic shock was diagnosed. The primary end point was death from any cause at 180 days. A composite safety end point was severe bleeding, limb ischemia, hemolysis, device failure, or worsening aortic regurgitation. Jason Wermers contributed to this report. Source: Møller JE, Engstrøm T, Jensen LO, et al. Microaxial Flow Pump or Standard Care in Infarct-Related Cardiogenic Shock. N Engl J Med. 2024 Apr 7 (Article in press). Rao SV. Mechanical Circulatory Support in Cardiogenic Shock — Persistence and Progress. N Engl J Med. 2024 Apr 7 (Article in press). Photo Credit: Jason Wermers/CRTonline.org Photo Caption: Jacob E. Møller, MD, PhD, DMSc, presents findings from the DanGer Shock Trial on Sunday at ACC.24 in Atlanta.