Comparison of myocardial work parameters between the transplanted heart and patients after other cardiac surgery

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Abstract Introduction The transplanted heart (HTX) has pathophysiological differences compared to standard hearts, partially understood. Early detection of abnormal grafts function (e.g. cellular or immune-mediated rejection, coronary artery vasculopathy) by advanced echocardiography can significantly improve management and prognosis of HTX patients. Speckle tracking-derived global longitudinal strain (GLS) and myocardial work (MW) have lower values in healthy HTX patients compared to controls. How much these abnormalities can be dependent on the surgical procedure itself is not known yet. Aim to compare MW values in stable patients after HTX and other cardiac surgical procedures to evaluate possible different impact of surgery on heart function. Methods in a monocentric study, we screened stable post-operative patients with a preserved left ventricular (LV) ejection fraction who underwent surgery at our hospital for HTX (group 1), aortic valve replacement, AVR, for severe aortic stenosis (group 2), mitral valve replacement, MVR, for severe primary regurgitation (group 3) and elective coronary artery bypass graft (CABG) (group 4). We excluded patients with other previous cardiac surgery, active pacemakers, BMI > 30, abnormal LV global function, more than mild regurgitation and/or stenosis, major post-operative complications absent informed consent. None of the HTX patients had previous history of rejection or coronary artery disease. All the surgical procedures required a median sternotomy and on-pump approach. All echocardiograms were performed between the 5th and the 12th postoperative day or within 2-3 months after HTX. For all patients, data regarding standard echo, GLS and MW parameters were collected and compared. One-way analysis of variance (ANOVA) and Bonferroni post-hoc tests were used to compare the variables among groups. Any independent predictor was tested to MW values reduction. Results Final population included 202 patients (137 males, 67%) with median age of 62 [50-86] years: 82 HTX, 40 AVR, 42 MVR and 40 CABG. MW-derived global work index (GWI), global constructive work (GCW) and global work efficiency (GWE) were significantly lower in group 2, 3 and 4 compared to HTX patients while having comparable global wasted work (GWW) (Table 1). Multivariate regression analysis showed significant relationship between all MW indices and GLS and blood pressure, as expected. GWI was also related to E/e’ ratio (b=0,131 p=0,033), GCW and GWW with LV end-diastolic volume, EDV (b=-0,177 p=0,012 and b=-0,261 p=0,030 respectively), GWE with EF (b=0,245 p=0,009) and EDV (b=0,210 p=0,027). Conclusions GLS and MW indices are lower after HTX than healthy general population. However, the transplanted heart has better MW indices compared to other post-operative patients. These preliminary results can suggest that the impact of surgical procedure on transplanted hearts might be only partially related to abnormal deformation and needs further characterization.