Hørsdal, Oskar Kjærgaard

Abstract Aims Cardiogenic shock (CS) is characterized by impaired left ventricular (LV) mechanical performance and adverse remodelling. We evaluated whether transthoracic echocardiography (TTE)-derived modified cardiac efficiency (mCE), integrating stroke work and residual LV volume, is associated with short- and long-term mortality in CS and whether its prognostic value differs by shock aetiology. Methods and results In this retrospective cohort study, consecutive adults admitted with CS to the cardiac intensive care unit at Mayo Clinic (2007–2018) were included if TTE was performed within 24 h. mCE was calculated as (stroke volume × estimated LV end-systolic pressure) divided by LV end-systolic volume and categorized into quartiles. Primary outcome was in-hospital mortality; secondary outcome was 1-year mortality. Multivariable logistic and Cox models adjusted for illness severity, comorbidity burden, shock aetiology, cardiac arrest, vasoactive therapy, and mechanical circulatory support. Among 667 patients, median mCE was 48 mmHg (IQR 32–74). In-hospital mortality was 28% and increased stepwise across decreasing mCE quartiles. The lowest quartile had a 2.5-fold higher adjusted odds of in-hospital death (OR 2.53; 95%CI: 1.49–4.37; P < 0.001). One-year mortality was 41%; the lowest quartile had a two-fold higher adjusted hazard of death (HR 2.05; 95%CI: 1.45–2.89; P < 0.001). Associations were stronger in acute coronary syndrome-related CS (interaction P = 0.035 for in-hospital; P = 0.015 for 1-year). Within the lowest quartile, reduced systolic pressure further amplified mortality risk. Conclusion Early TTE-derived mCE was independently associated with short- and long-term mortality in CS, particularly in acute coronary syndrome-related CS, and captured the interaction between ventricular remodelling and mechanical performance underlying high-risk phenotypes.

Abstract Background Cardiogenic shock (CS) is characterized by critically low cardiac output and impaired myocardial energy transfer to cardiac work. Left-ventricular (LV) cardiac mechanical efficiency (CE), defined as the fraction of total pressure-volume area (PVA) converted to external work (EW), captures how effectively the LV converts energy into stroke work. Because CE integrates load, chamber volumes, and pump performance into a single physiologic construct, it may directly reflect the energy-work mismatch that characterizes CS. The prognostic value of transthoracic echocardiography (TTE)-derived CE for in-hospital outcomes in CS remains uncertain. Purpose To determine whether TTE-derived CE measured within 24 hours of admission predicts in-hospital mortality in patients with CS, and to compare its discriminatory performance with LV ejection fraction (LVEF). Methods Data from CS patients admitted between 2007 and 2018 were analyzed. First LV end-systolic pressure (LVESP=0.9×systolic blood pressure), stroke volume (SV), and LV end-diastolic pressure (LVEDP, estimated using the Nagueh formula) was estimated. CE was then estimated based on EW (EW=(LVESP×SV)−(SV×LVEDP)), potential energy (PE=0.5×LVESP×LV end-systolic volume) and PVA (EW+PE) as CE=EW/PVA×100. We assessed CE and LVEF by TTE performed within 24 hours of admission. Patients were separated into tertiles of CE: high (>47%), moderate (36% < CE ≤47%), and low (CE ≤36%). The primary endpoint was in-hospital mortality. A key secondary endpoint was cardiac intensive care unit (CICU) mortality. Associations were tested with multivariable logistic regression (pre-specified covariates including LVEF). Results A total of 577 patients were included. Median age was 69 (IQR: 59-78) years, 38% were females and 65% had acute coronary syndrome. CICU mortality was 20% and total in-hospital mortality was 29%. Patients with low CE had a lower LVEF compared with patients with moderate or high CE (21% (IQR:19-24%) vs 31% (IQR: 28-33%) and 45% (39-51%) respectively). Median CE was 40.5% (IQR 31.8–51.0%) and was lower for in-hospital deaths (37.1% vs 42.1%, P<0.001). Patients with lower CE exhibited significantly higher CICU (P=0.003) and in-hospital mortality (P<0.001; Figure 1). Patients with CE in the lowest tertile had significantly increased risk of CICU and in-hospital death (Figure 2) compared with moderate or high CE tertiles. In multivariate analysis, every 1% decrease in CE corresponded to an 10% increased risk of CICU death and an 8% increased risk of in-hospital death. When both CE and LVEF were included in the same multivariate model, both were significant predictors of CICU death, while only CE remained a significant predictor of in-hospital death. Conclusion In patients with CS, TTE-derived CE measured within 24 hours of admission predicts early risk of death, underscoring the prognostic importance of LV energy-work coupling as a marker of disease severity beyond LVEF measurement.Figure 1: Figure 2: