Transformation in Acute MI Care: Door to Balloon or Door to Unload?

By Dr. Nazli Okumus - March 29, 2023

The 2023 sessions of Technology and Heart Failure Therapeutics (THT2023) took place on March 20-22nd, 2023 in Boston with great enthusiasm in technologies that are in the pipeline and amazing discussions about ongoing trials that will shape the future of our clinical practice. One of the most striking sessions was “Unloading in AMI: Changing the paradigm from DTB to DTU” presented by Dr. Navin Kapur. He talked about unloading the left ventricle in anterior MI prior to reperfusion to prevent myocardial injury.

Since the 1970’s, acute management of ST elevation myocardial infarction has focused on timing of revascularization to prevent myocardial injury (MI). In the light of benefits shown in multiple studies, timely revascularization with balloon angioplasty followed with stenting remained as the standard of care. Despite significant improvements in health care systems to meet the Door-to-balloon time (DTB) of 90 minutes or less, heart failure continues to be an important issue. Approximately 35% of new in-hospital heart failure events in patients older than 65 years of age happen within the context of their first acute MI.

In 2013, Navin Kapur et al. sought to answer the question if unloading the left ventricle while delaying coronary reperfusion can prevent myocardial injury. They showed a reduction in total infarct size in adult swine models with initial 30 minute unloading time prior to reperfusion when compared to standard of care prioritizing immediate reperfusion. Subsequently, the DTU-STEMI Pilot trial (Door-To-Unload in STEMI Pilot Trial) was designed to test the safety and feasibility of this model in humans. In this multicenter, prospective, randomized trial, 50 patients with anterior MI were assigned to Impella CP with immediate reperfusion versus LV unloading with Impella CP for 30 minutes followed by reperfusion. Interestingly, there was no significant difference in major cardiovascular and cerebrovascular events in these two groups. Moreover, the infarct size assessed by cardiac MRI at 30 days did not differ in the two arms.

Guided with the shown benefits in animal models followed with the reassuring safety and feasibility results that were shown in the Pilot study, the STEMI-DTU Pivotal trial was designed. This is a multicenter randomized controlled trial that was designed to compare LV unloading with Impella CP for 30 minutes followed with delayed revascularization to immediate revascularization as standard of care in acute anterior MI. With more than 300 individuals enrolled so far in the Unites States and Europe, the results are eagerly anticipated.

Over the past decade, we have witnessed great changes in the management of heart failure and cardiogenic shock with emerging novel uses of temporary mechanical support devices and new medical therapies. THT2023 hosted multiple discussions regarding the ongoing trials about the use of already existing devices as well as those that are still undergoing safety and feasibility studies. The STEMI-DTU Pivotal Trial is a phenomenal example of why we should continue to question at every area of clinical practice how we can improve the care even if there is robust data behind the current practice. We are all excited to see if the results of this trial are going to “shift the paradigm from DTB to DTU”.

Dr. Nazli Okumus is a cardiology fellow at Allegheny Health Network and served as a CardioNerds Conference Scholar for the 2023 Technology and Heart Failure Therapeutics (THT23).


Ezekowitz, Justin A., et al. “Declining in-hospital mortality and increasing heart failure incidence in elderly patients with first myocardial infarction.” Journal of the American College of Cardiology 53.1 (2009): 13-20.

Kapur, Navin K., et al. “Mechanically unloading the left ventricle before coronary reperfusion reduces left ventricular wall stress and myocardial infarct size.” Circulation 128.4 (2013): 328-336.

Kapur, Navin K., et al. “Unloading the left ventricle before reperfusion in patients with anterior ST-segment–elevation myocardial infarction: a pilot study using the Impella CP.” Circulation 139.3 (2019): 337-346.

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