Outcomes in Smaller Body Size Adults After HeartMate 3 Left Ventricular Assist Device Implantation

Outcomes in patients with smaller body size after HeartMate 3 left ventricular assist device (HM3) implantation are not well characterized. We sought to evaluate outcomes in smaller vs larger body surface area (BSA) patients in the MOMENTUM 3 pivotal trial and its Continued Access Protocol cohort.

The analysis cohort included 1015 HM3 patients divided into 2 groups: BSA ≤1.70 m² (small patients, n = 82) and BSA >1.70 m² (large patients, n = 933). The composite primary end point was survival at 2 years free of disabling stroke or reoperation to replace or to remove a malfunctioning device. Adverse events were compared between groups.

Smaller patients were more frequently women (56.1% vs 17.7%; P < .001) and had lower prevalence of diabetes (28.1% vs 43.9%; P = .005) and hypertension (51.2% vs 71.9%; P < .001), larger median indexed LVEDD (normalized by BSA, 40 vs 33 mm/m²; P < .001), and lower median serum creatinine concentration (1.1 vs 1.3 mg/dL; P < .001). The proportion of patients achieving the composite end point at 2 years was 77% in both groups (adjusted hazard ratio, 1.14; 95% CI, 0.68-1.91; P = .62). Two-year adverse event rates were also similar between groups except for sepsis (6.1% vs 14.9%; P = .029) and cardiac arrhythmias (24.4% vs 35.3%; P = .005), which were higher in the larger patients.

Outcomes after HM3 implantation were comparable between small and large patients. Smaller body size should not be used to deny HM3 implantation in patients who are otherwise suitable candidates for durable mechanical circulatory support.