Echocardiographic surrogate of left ventricular stroke work in a model of brain stem death donors

Background The commonest echocardiographic measurement, left ventricular ejection fraction, can not necessarily predict mortality of recipients following heart transplantation potentially due to afterload dependency. Afterload‐independent left ventricular stroke work index (LVSWI) is alternatively recommended by the current guideline; however, pulmonary artery catheters are rarely inserted in organ donors in most jurisdictions. We propose a novel non‐invasive echocardiographic parameter, Pressure‐Strain Product (PSP), as a potential surrogate of catheter‐based LVSWI. This study aimed to investigate if PSP could correlate with catheter‐based LVSWI in an ovine model of brain stem death (BSD) donors. The association between PSP and myocardial mitochondrial function in the post‐transplant hearts was also evaluated. Methods Thirty‐one female sheep (weight 47 ± 5 kg) were divided into two groups; BSD ( n = 15), and sham neurologic injury ( n = 16). Echocardiographic parameters including global circumferential strain (GCS) and global radial strain (GRS) and pulmonary artery catheter‐based LVSWI were simultaneously measured at 8‐timepoints during 24‐h observation. PSP was calculated as a product of GCS or GRS, and mean arterial pressure for PSP circ or PSP rad , respectively. Myocardial mitochondrial function was evaluated following 6‐h observation after heart transplantation. Results In BSD donor hearts, PSP circ ( n = 96, rho = .547, p < .001) showed the best correlation with LVSWI among other echocardiographic parameters. PSP circ returned AUC of .825 to distinguish higher values of cardiomyocyte mitochondrial function (cut‐off point; mean value of complex 1,2 O 2 Flux) in post‐transplant hearts, which was greater than other echocardiographic parameters. Conclusions PSP circ could be used as a surrogate of catheter‐based LVSWI reflecting mitochondrial function.