Pectoralis muscle measures on preoperative computed tomography are strong predictors of early rehospitalization after left ventricular assist device implantation

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background/Introduction Skeletal muscle mass is reduced in severe heart failure and has a significantly impacts on subsequent outcomes and quality of life. The assessment of pectoralis muscle measures by computed tomography (CT) scan may be predictive of outcomes after left ventricular assist device (LVAD) implantation. Purpose This study aims to assess preoperative pectoralis muscle measures before LVAD implantation to predict early rehospitalization of the patient. Methods We measured the cross-sectional area and mean CT values of the unilateral pectoralis muscle (PHUm: mean Hounsfield unit of pectoralis muscle) by CT scans within 3 months before surgery in patients who underwent HeartMate 3 implantation for the bridge to transplant (BTT) or destination therapy (DT) at our hospital, by August 2022. The cross-sectional area of the unilateral pectoralis muscle was corrected for body surface area (PMI: pectoralis muscle index). The pectoralis muscle was measured by SYNAPSE VINCENT image analysis (Fuji Film) using an axial section of the superior margin of the aortic arch (Figure A). The area under the curve (AUC), sensitivity, and specificity of each index was calculated by receiver operating characteristic (ROC) analysis for the prediction accuracy of PHUm, PMI, and the product of PHUm and PMI in rehospitalization 30, 60, 90 and 180 days from discharge. Results Of reviewed 39 patients who underwent HeartMate 3 implantation, 32 (82%) were male, and 32 (82%) underwent BTT. The median age at LVAD implantation was 52 years (interquartile range [IQR], 42–57). During the follow-up period after discharge (median: 520 days, IQR: 116–707), 19 patients (53%) had unscheduled hospitalizations due to 8 LVAD-related infections, 1 heart failure, 1 cardiac arrhythmia, and 9 other reasons. The median time between discharge and rehospitalization was 70 days (IQR, 31–139). ROC analysis showed that the AUC was particularly high for early rehospitalization within 30 days, with the optimal cutoff of 21.8 Hounsfield unit (HU) for PHUm (sensitivity 0.903, specificity 0.800, AUC 0.884), 6.37 cm2/m2 for PMI (sensitivity 0.806, specificity 0.800, AUC 0.735), and 142.8 for the product of PHUm and PMI (sensitivity 0.903, specificity 1.000, AUC 0.948) (Figure B). Conclusion The product of PHUm and PMI may be a strong predictor of early rehospitalization within 30 days of discharge after LVAD implantation.