7.2 Hemodynamic Support for STEMI: Door to Unloading Times and Do We Need Systems of Care?

These proceedings summarize the educational activity of the 16th Biennial Meeting of the International Andreas Gruentzig Society held January 31-February 3, 2022 in Punta Cana, Dominican Republic

Faculty Disclosures     Vendor Acknowledgments

2022 IAGS Summary Document

Statement of the problem or issue

Data from randomized trials of primary PCI for STEMI clearly show that both acute and long-term survival are related to infarct size.¹ Importantly, as modern reperfusion therapies like primary PCI (pPCI) have improved survival of the acute infarct event over time, and in-hospital mortality has declined as a consequence, the incidence of later heart failure has increased. ²

Gaps in knowledge

The question arises whether there are measures we can take that will reduce infarct size and reduce the later development of heart failure. Research studies in animal models showed benefits of left ventricular (LV) unloading prior to reperfusion. Based on these, a small clinical pilot trial was performed to determine if LV unloading with Impella for 30 minutes prior to reperfusion in anterior STEMI was possible and safe.  Results showed there was no increase in infarct size with 30 minutes delay to reperfusion.³ Exploratory subgroup analyses showed that larger infarcts had greater protection with LV unloading.  Nevertheless, many other knowledge gaps remain: What is the impact of ischemia time before treatment? What is the optimal unloading time (both pre- and post reperfusion)? What role do medications to reduce blood pressure and heart rate play in optimizing Impella function? What is the required reduction in outcome events needed to decide if unloading is favorable or not?

Possible solutions and future directions

The STEMI-DTU trial (NCT03947619) is currently enrolling patients. This is a prospective, multicenter, randomized, controlled open-label, 2-arm trial.  Patients in the investigative arm will receive an Impella pump, undergo 30 minutes of support prior to reperfusion with pPCI, and then 4-6 hours of support after reperfusion. In the control arm patients will receive usual pPCI immediately. The primary comparator is infarct size measured by cardiac MRI. This trial should generate further insights into the effects of LV unloading on infarct size in STEMI.

References

1. Stone GW, Selker HP, Thiele H, et al. Relationship between infarct size and outcomes following primary PCI: patient-level analysis from 10 randomized trials. J Am Coll Cardiol. 2016;67(14):1674-83. doi:10.1016/j.jacc.2016.01.069

2. Ezekowitz JA, Kaul P, Bakal JA, Armstrong PW, Welsh RC, McAlister FA. Declining in-hospital mortality and increasing heart failure incidence in elderly patients with first myocardial infarction. J Am Coll Cardiol. 2009;53(1):13-20. doi:10.1016/j.jacc.2008.08.067

3. Kapur NK, Alkhouli MA, DeMartini TJ, et al. Unloading the left ventricle before reperfusion in patients with anterior ST-segment-elevation myocardial infarction. Circulation. 2019;139(3):337-346. doi:10.1161/CIRCULATIONAHA.118.038269