Abstract Body (Do not enter title and authors here): Background:
The Society for Cardiovascular Angiography and Interventions (SCAI) staging system is a crucial tool for categorizing cardiogenic shock (CS) and guiding interventions. SCAI staging is traditionally static and may not capture dynamic changes. We evaluated the impact of axillary mechanical circulatory support and SCAI stage transition in patients with CS supported until heart transplantation.

Methods:
A retrospective study was conducted on patients with Impella support as bridge to transplant. Hemodynamic and vasoactive support parameters were collected and SCAI stage recorded at baseline and after 72 hours.

Results:
36 patients were included in the analysis. The median age was 61 (52 – 68) with an EF of 19% (15-26%) (Figure 1). Before Impella placement, the distribution of patients across SCAI stages was as follows: 19 patients in SCAI B, 8 patients in SCAI C, and 9 patients in SCAI D. After 72 hours of Impella support, 7 patients initially classified as SCAI C transitioned to SCAI B with one deteriorating to SCAI D (Figure 2). Patients in SCAI D showed notable improvement, with 8 out of 9 patients transitioning to SCAI B.

For patients initially SCAI B, RA changed from 10 to 11 mmHg, and PCWP decreased from 23 to 17 mmHg. The Fick CI increased from 2.53 to 3.02 L/min/m² (p=0.04), and the vasoactive inotropic score (VIS) decreased from 7.5-5.0 (p=0.05).

In patients initially classified as SCAI C, RA pressure decreased from 13 to 8 mmHg, and PCWP reduced from 32 to 30 mmHg. The Fick CI improved from 1.79 to 2.61 L/min/m² (p<0.001), while the VIS decreased from 9.2 to 6.3 (p=0.004).

For those initially in SCAI D, RA pressure reduced from 8 to 5 mmHg, and PCWP decreased from 27 to 18 mmHg. The Fick CI increased from 1.55 to 2.67 L/min/m² (p=0.002), and the VIS was notably reduced from 4.75 to 3.8 (p=0.36).

All 36 patients survived to heart transplantation without major pre-transplant complications.

Conclusion:
SCAI stage C-E mortality ranges from 25 – 50% or worse. Implementing Impella 5.5 support reduced SCAI severity and may be associated with improved survival in HFCS. We demonstrated lower VIS after Impella 5.5 and a 100% event free survival to heart transplantation despite a 25% baseline SCAI D cohort. Larger data should be evaluated to assess this trend.