Inside the cavity: left ventricular geometry and device-related events with temporary mechanical circulatory support in cardiogenic shock patients

The microaxial flow pump system provides effective temporary mechanical circulatory support (tMCS) in cardiogenic shock (CS) patients, but device-related positioning and flow issues, hemolysis, and thromboembolic events may occur. Because the pump operates within the left ventricular (LV) cavity, ventricle–device coupling may be influenced by LV geometry.

The aim of the study was to evaluate the relationship between LV geometry and the microaxial flow pump, and the impact of LV geometry on device-related complications.

We conducted a retrospective study of patients with CS supported with a microaxial flow pump. Pre-implant echocardiography was used to classify LV geometry (no remodeling, concentric remodeling, concentric hypertrophy, eccentric hypertrophy) and to identify spherical ventricles (sphericity index >0.6). Outcomes included device malrotation, suction/reduction of flow, pump malfunction, impingement, hemolysis, stroke/TIA, and major bleeding. Outcomes were compared across geometry groups and by sphericity (>0.6 vs ≤0.6).

Among 97 CS patients supported with a microaxial flow pump (mean age 59 ± 12 years; 78.3% male; mean LVEF 22 ± 12%; AMI-CS in 57.7%), LV geometry differed across clinical presentations: 48.4% no-remodeling, 18.5% concentric remodeling, 8.2% concentric hypertrophy, 24.7% eccentric hypertrophy, 69% spherical ventricles. Overall, device-related complications included malrotation in 36.1% of cases, impingement in 23.7%, suction/reduction of flow events in 36.1%, pump malfunction in 7.2%, hemolysis in 36.1%, stroke in 13.4%, and major bleeding in 27.8%. Hemolysis was significantly more frequent in patients with concentric hypertrophy (75% of cases; p = 0.009). Pump malfunction was more common with a sphericity index ≤ 0.6 (5/30, 16.7%) than with > 0.6 (2/67, 3.0%; p = 0.028). Malrotation showed a trend toward higher rates in eccentric hypertrophy (11/24, 45.8%; p = 0.093). Rates of suction/reduction of flow, impingement, and stroke/TIA did not differ between groups (p > 0.05). Major bleeding showed a trend toward higher rates in patients with concentric hypertrophy (p = 0.09).

LV geometry may influence microaxial flow pump performance and safety. Concentric hypertrophy is associated with higher rates of hemolysis, lower LV sphericity (≤0.6) is associated with more pump malfunctions, and malrotation is more likely in eccentric hypertrophy. Pre-implant geometric assessment may improve implantation strategy, surveillance, and management to mitigate device-related complications.