Clinical Research & Data, Unloading, Protected PCI

TCT 2022: Lessons Learned in STEMI DTU™ Pilot Study


Navin Kapur, MD, opens this presentation of lessons learned from the DTU STEMI™ pilot trial with a case study highlighting the significance of the study. The vibrant, 70-year-old patient presents about an hour after developing chest pain and consents for enrollment in STEMI DTU. He is randomized to the control arm, which receives LV unloading with Impella® and immediate reperfusion, in contrast to the treatment arm that receives Impella unloading with a 30-minute delay in reperfusion. Post-PCI, the patient feels great and an echo shows left ventricular ejection fraction (LVEF) is >50%. Unfortunately, cardiovascular magnetic resonance (CMR) at days three to five shows a massive anterior infarct, highlighting Dr. Kapur’s first lesson learned: 

  • Lesson 1: Reperfusion does not equal recovery.

Explaining that heart attacks lead to heart failure, Dr. Kapur emphasizes, “The goal of DTU is to not only salvage myocardium acutely, but also to reduce the burden of overall ischemic heart failure.” 

Looking at results from the STEMI DTU pilot study, Dr. Kapur highlights two lessons that led to the pivotal STEMI DTU trial: 

  • Lesson 2: LV unloading + delayed reperfusion is feasible, as demonstrated by 100% operator compliance in the pilot study.
  • Lesson 3: LV unloading + delayed reperfusion does not increase infarct size.

Additional lessons learned from the per-protocol analysis of the STEMI DTU pilot trial:

  • Lesson 4: Per-protocol execution requires rigorous monitoring.

"36% of DTU pilot patients did not adhere to the study protocol,” Dr. Kapur explains. “Either they didn’t get the CMR, they didn’t meet the ST elevation requirement, or they didn’t have a culprit LAD lesion.”

  • Lesson 5: The sum of precordial ST segment elevation impacts infarct size.

“There’s a stepwise increase in the infarct size based on the initial ECG ST elevation sum.”

  • Lesson 6: Baseline LV ejection fraction (V-gram) impacts infarct size.

​​​​​​​“If you enroll patients with low EF at the time of the baseline V-gram, this is also associated with higher infarct size.”

  • Lesson 7: 30 minutes of delay to PCI enhances myocardial salvage with unloading.
  • Lesson 8: Infarct size is associated with microvascular obstruction (MVO) and 90-day LVEF and LV volumes.

Dr. Kapur announces that the STEMI DTU pivotal trial is now enrolling in the US and Europe and one of the most important lessons learned in conducting the pilot, and now pivotal, study is:

  • Lesson 9: It takes a community on-call with 24/7 enrollment to succeed.

Impella heart pumps are not FDA approved for use in STEMI patients without cardiogenic shock.

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