Heart Failure Severity Stratification Beyond INTERMACS Profiles: A Step Toward Optimal Left Ventricular Assist Device Timing

The purpose of this analysis is to determine whether pectoralis muscle measures quantified on pre left ventricular assist device (LVAD) computerized tomography (CT) scans can identify subgroups of patients with differential disease severity within each Interagency Registry for Mechanical Circulatory Support (INTERMACS) profile. Patients with chest CTs performed ≤3 months before LVAD implantation at University of Minnesota (n = 143) and Houston Methodist Hospital (n = 133) were identified from the larger LVAD cohorts (University of Minnesota n = 353, Houston Methodist =278). Unilateral Pectoralis muscle mass indexed to body surface area and pectoralis muscle attenuation were measured on preoperative chest CT scans. Patients within each INTERMACS profile were separated into HIGH and LOW PEC muscle groups. Kaplan-Meier and multivariable cox regression analyses were performed to compare mortality among INTERMACS profiles by HIGH and LOW PEC muscle groups. INTERMACS 3 and 4 patients in the HIGH PEC groups had the highest survival on LVAD support (1 year survival 85% vs. 68%, log rank P = 0.0001). Being in this group was associated with a 60% reduction in the hazards rate (HR) of death after LVAD (adjusted HR 0.40, 95% confidence interval 0.25-0.62). Additionally, renal function deterioration in the year before LVAD was associated with lower INTERMACS profiles and lower measured pectoralis muscle tissue attenuation at the time of LVAD implantation. INTERMACS 3 and 4 patients with the highest pectoralis muscle measures had the best survival after LVAD. The association between renal function deterioration and sarcopenia suggests these muscle changes are progressive. Computerized tomography quantification of sarcopenia may help identify optimal LVAD implantation timing.