Article

A27 - Impact of Gender and Ischaemic Time in Anterior STEMI with Left Ventricular Unloading and Delayed Reperfusion: A Sub-study from the STEMI-DTU Safety and Feasibility Trial

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Citation:Interventional Cardiology Review 2019;14(3 Suppl 1):A27.

Correspondence: William O’Neill, woneill1@hfhs.org

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Background: Prolonged ischaemic time increases myocardial infarct size (IS), which increases the risk of heart failure and mortality. However, pre-clinical work has demonstrated that mechanically unloading the left ventricle (LV) and delaying reperfusion reduces IS. The STEMI Door-To-Unload Pilot Trial (STEMI-DTU) demonstrated the feasibility and safety of LV unloading with delayed reperfusion in non-shock ST-elevation MI (STEMI) patients.

Methods: This multicentre, phase I randomised trial enrolled 50 patients with anterior STEMI referred for primary percutaneous coronary intervention within 1–6 hours of symptom onset. Patients were randomised to primary unloading with an Impella CP, followed by either 30 minutes of unloading prior to reperfusion (U-DR) or immediate reperfusion (U-IR). Here, we investigate two populations that may show additional benefit with LV unloading: patients with high ST-elevation (STE) and women.

Results: Of the 50 patients enrolled, 30 had STE >6 mm and cardiac magnetic resonance (CMR) at the defined timepoints (U-IR-14, U-DR-16). Baseline characteristics were similar between groups. The symptom onset to reperfusion (SOR) time for patients’ CMR data with STE >6 was 174 minutes in the U-IR group versus 227 minutes in the U-DR group (p=0.05). IS as a percentage of the area at risk (AAR) at 3–5 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 these, 10 women and 30 men had CMR evaluations at 3–5 days and 30 days. Women tended to be older than men, 65 versus 57 years (p=0.09) and have lower BMI. SOR time was 206 minutes versus 216 minutes for women versus men (p=NS). IS/AAR was 34.8% in women versus 51.7% in men (p=0.05), and 22.7% in U-DR women versus 48.0% in U-DR men respectively (p=0.001). Infarct size as a percentage of 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.