Impact of Gender and Ischemic Time in Anterior STEMIs With Left Ventricular Unloading and Delayed Reperfusion: A Substudy From the STEMI-DTU Safety and Feasibility Trial
Kapur N, and O'Neill W. Impact of Gender and Ischemic Time in Anterior STEMIs With Left Ventricular Unloading and Delayed Reperfusion: A Substudy From the STEMI-DTU Safety and Feasibility Trial. J Am Coll Cardiol 2019; 74(13):B122.
J Am Coll Cardiol
Background: Prolonged ischemic time increases myocardial infarct size, which increases risk of heart failure and mortality. However, preclinical work has demonstrated that mechanically unloading the left ventricle (LV) and delaying reperfusion reduces infarct size. The STEMI-DTU (STEMI Door-To-Unload Pilot Trial) demonstrated the feasibility and safety of LV unloading with delayed reperfusion in nonshock ST-segment elevation myocardial infarction (STEMI) patients. Methods: This multicenter, phase 1 randomized trial enrolled 50 patients with anterior STEMI referred for primary percutaneous coronary intervention within 1 to 6 h of symptom onset. Patients were randomized to primary unloading with an Impella CP followed by either 30 min of unloading prior to reperfusion (U-DR) or immediate reperfusion (U-IR). Here we investigate 2 populations that may show additional benefit with LV unloading: patients with high ST-segment elevation (STE) and women. Results: Of the 50 patients enrolled, 30 had STE >6 mm and CMR at the defined time points (U-IR-14, U-DR-16). Baseline characteristics were similar between groups. The symptom onset to reperfusion (SOR) time for patients with CMR data with STE >6 mm was 174 min in the U-IR group versus 227 min in the U-DR group (p = 0.05). Infarct size as a percent area at risk (IS/AAR) at 3 to 5 days in this population was 59.9% versus 44.1% in the U-IR versus U-DR groups (p = 0.04). Of the 50 patients, 12 were women and 38 were men; of those, 10 women and 30 men had CMR evaluations at 3 to 5 and 30 days. Women tended to be older than men (65 years vs. 57 years; p = 0.09) and have lower body mass index (BMI). SOR time was 206 min versus 216 min for women versus men (p = NS). IS/AAR was 34.8% versus 51.7% in women versus men (p = 0.05), 22.7% versus 48.0% comparing U-DR women versus U-DR men, respectively (p = 0.001). Infarct size as a percent LV mass at 30 days was 10.5% versus 15.3% (p = 0.24). This trend was preserved when matched by BMI. However, when matched by LV mass, women and men had similar infarct sizes. Conclusion: Infarct size was reduced using LV unloading with delayed reperfusion in patients with large anterior STEMI despite an increase in SOR time. Strong trends were seen in infarct size reduction with unloading in women versus men and may be related to the degree of unloading relative to LV mass.