Abstract Body (Do not enter title and authors here): Introduction/Background:
Ventricular Septal Defect (VSD) is a well-known and often fatal complication of myocardial infarction (MI), particularly when presentation is delayed. The mortality of patients treated with medical therapy alone approaches 100%. Intra-aortic balloon pump (IABP) remains first-line temporary mechanical circulatory support (tMCS) as bridge therapy for surgical repair. However, at times counter pulsation alone does not provide adequate hemodynamic support. We present a single center experience using Impella 5.5 as a bridge to delayed surgical repair.

Research Hypothesis:
Impella 5.5 can be effective bridge therapy for delayed VSD repair in patients inadequately supported by other tMCS.

Methods:
We performed a retrospective chart review of all patients with post-MI VSD implanted with Impella 5.5 from 2021-2025. We evaluated demographic data, type and duration of tMCS support, development of refractory hypoxemia, survival, and complications related to tMCS.

Results:
Seven patients with post MI VSD were reviewed, mean age was 63.9, six patients were male, one patient was female, five patients had RCA infarct, and two patients had LAD infarct. Two of the seven patients were deemed poor surgical candidates due to stroke following impella 5.5 placement and mitral valve endocarditis, these patients died shortly after Impella 5.5 support was weaned. (Figure 1, Patients 1 and 2 respectively). The remaining five patients (Figure 1, Patients A-E) had stability or improvement in their hemometabolic profiles following placement of Impella 5.5 and underwent repair of VSD with bovine patch. For patients A-E, the average time on tMCS was 15 +/- 8.1 days and the average time on Impella 5.5 was 11 +/- 7.2 days. Known survival in post-operative group is 100% to date (Table 1).

Conclusion:
Standard of care for post-MI VSD involves immediate hemodynamic and hemometabolic resuscitation, and delayed surgical repair to optimize operative success. While IABP is standard of care, patients may require expedited surgery due to hemodynamic or hemometabolic instability, which results in unfavorable conditions for patch durability. Despite small case series, guidelines for IMPELLA 5.5 state post-MI VSD as a contraindication for Impella placement as it could cause worsening right to left shunting. Notably, no patients experienced refractory hypoxemia. This case series suggests Impella 5.5. may be the optimal strategy for bridging to delayed surgical repair in post-MI VSD.