Novel semi-invasive pressure-volume loop analysis for hemodynamic assessment and risk stratification across SCAI stages in cardiogenic shock

Background Cardiogenic shock (CS) necessitates precise hemodynamic assessment for optimal therapy. Integrating pulmonary artery catheters (PAC) with echocardiography allows for real-time, semi-invasive pressure-volume (PV) loop generation, capturing ventricular function without the use of conductance catheters. Purpose This study aims to demonstrate the feasibility of real-time PV loop construction and correlate PV-derived metrics with CSWG-SCAI stages. Methods We studied 32 patients (SCAI C+ CS; 26 AMI-CS, 6 HF-CS) from February-October 2024, assessing hemodynamics at PAC placement and at 6, 12, 18, 24, 48, and 72 hours thereafter. Using ECHO+PAC data, we generated 198 PV loops and extracted CSWG-SCAI stages (Table 1). Continuous data are presented as medians (IQR), while categorical data are shown as counts (%), with SCAI stage comparisons performed using ordinal regression with a logit link. Results Heart rate increased across A/B»E (P=0.002), whereas mean arterial pressure and diastolic blood pressure declined significantly (P<0.001). Right atrial pressure (RAP) increased across stages (P=0.001), while cardiac output and cardiac power output decreased (P<0.001). PAPI progressively decreased (P=0.005), indicating worsening right ventricular function. The utilization of mechanical circulatory support varied, with the use of intra-aortic balloon pump (IABP) and Impella increasing with severity. Lactate levels rose (P<0.001) and pH declined significantly (P<0.001), accompanied by an increase in PaCO₂, indicating a deteriorating acid-base balance; HCO₃⁻ levels also decreased (P<0.001), consistent with progressive metabolic acidosis. PaO₂/FiO₂ declined significantly (P=0.041). pVO₂ increased across A/B»E (P=0.011), suggesting a worsening oxygen delivery-consumption imbalance. ΔCO₂ remained stable (P=0.365), while O₂ER decreased, with no significant findings (P=0.645). There was a significant decrease in VO₂ as stages progressed (P=0.007), indicating impaired oxygen utilization, alongside a progressive increase in the DO₂/VO₂ ratio (P=0.009). We observed a continued deterioration in left ventricular (LV) stroke work index (P<0.001). Right ventricular function was also impaired, with a significant decrease in RVSWi (P<0.001). For the PV loop analysis: Arterial elastance (Ea) increased across CSWG-SCAI stages (P<0.001), while end-systolic LV elastance (Ees) showed a significant decrease (P=0.025), indicating worsening ventricular-arterial uncoupling, although no differences in VAC were noted (P=0.758). Pressure-volume area (PVA) decreased progressively (P<0.001), suggesting a reduction in overall myocardial energy generation and worsening hemodynamics. (Figure 1) Conclusion A novel semi-invasive method for generating PV loops without the need for conductance catheters reveals a progressive decline in myocardial efficiency and hemodynamic deterioration correlated with the progression of CSWG-SCAI, potentially aiding in the management of CS.Table 1.CSWG SCAI and hemometabolic dat Figure 1.