A new semi-invasive approach to pressure-volume loop assessment of mechanical circulatory support in cardiogenic shock

Background The optimal mechanical circulatory support (MCS) strategy for cardiogenic shock (CS) remains debated, particularly in acute myocardial infarction-related CS (AMI-CS) and heart failure-related CS (HF-CS). Traditional assessments may not fully capture ventricular loading, limiting the understanding of MCS effects. Purpose we introduce a novel method to derive PV loops using PAC & echo data, without requiring an impedance catheter for MCS effect comaprisson. Methods 32 patients with CS and different MCS strategies generated 198 PV-loops at baseline, during support, and post-device removal. Statistical comparisons employed multinomial regression, using baseline as the reference. Results Impella: During support, cardiac output (CO) increased (p=0.048), reflecting effective left ventricular (LV) unloading. PCWP (p=0.022) and mean pulmonary artery pressure (mPAP, p=0.045) decreased. SVRi (p=0.026) declined, suggesting enhanced systemic perfusion. PV loops demonstrated a leftward shift with reduced end-diastolic volume (EDV) and improved end-systolic elastance (Ees). VA coupling (VAC, p=0.017) improved, indicating better cardiovascular efficiency. After the device removal, CO remained stable, but PV loops exhibited a partial rightward shift, reflecting LV reloading. The increase in EDV and end-systolic volume (ESV) suggested a partial reversal of the unloading effect, while end-systolic pressure decreased (p=0.049), and Ea remained lower than baseline (p=0.04), indicating sustained afterload reduction. IABP: During support, PCWP (p=0.003) and mPAP (p=0.014) decreased. Right atrial pressure (RAP, p=0.005) also declined, suggesting preload reduction. PV loops showed a modest leftward shift indicating mild LV unloading. However, VAC remained stable, and stroke work did not change (p>0.05). After device removal, CO increased further (p=0.037), and PV loops demonstrated improved systolic function. PCWP remained lower than baseline (p=0.044), and arterial elastance (Ea) improved, suggesting a mild enhancement in VA interaction. EDV and ESV showed moderate increases, reflecting LV reloading. No-Support (AMI-CS): CO increased (p=0.03), reflecting partial hemodynamic recovery. However, PV loops showed no changes (p>0.05), indicating persistent LV dysfunction and suboptimal VAC (p=0.121). Only stroke work displayed a trend of improvement (P=0.054). HF-CS: PCWP (p=0.042) and RAP (p=0.014) decreased. PAPI and the RAP/PCWP improved (p=0.038). However, no significant changes were observed in PV loops, indicating that LV performance remained unchanged despite improved RV function and reduced congestion. Conclusions This study presents a novel methodology for deriving PV loops. Impella support demonstrated substantial LV unloading, while IABP provided only modest improvements. In HF-CS, decongestion was the primary benefit, with improvements in the RV function. PV loops optimization varies by MCS strategy.Fig1.PV-loop creation & PV-loops in MCS Fig2.