Myocardial work indices in living kidney donor population

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Living kidney donors represent a very special group of patients who are screened for cardiovascular morbidity preoperatively and remained with mildly reduced renal function after unilateral nephrectomy. The effect of unilateral nephrectomy on cardiovascular disease progression or subclinical cardiac dysfunction is still controversial. Myocardial deformation imaging allows left ventricular function quantification beyond ejection fraction. Non invasive assessment of myocardial work (MW) is a novel, promising speckle tracking- based method which can provide us to detect subtle myocardial dysfunction with advantages of load independency. We aimed to assess the impact of mildly reduced renal function after kidney donation, on subclinical cardiac structural and functional status. Methods We included seventeen kidney donors and seventeen age and sex matched healthy controls. All participants underwent transthoracic echocardiography (TTE). In addition to standard TTE measurements, 2D speckle – tracking based strain analysis was performed for left ventricle (LV) and right ventricle (RV). We also calculated Global Work Index (GWI) as the area of LV pressure-strain loop as a product of strain and x systolic blood pressure. MW efficieny (MWE), Global Constructive Work (GCW) and Global Wasted Work (GWW) were also calculated. Results There was no difference between the patients and the control group, regarding conventional parameters such as LV ejection fraction, Tricuspidal annular systolic excursion (TAPSE) and systolic pulmonary artery pressure. Left ventricular global longitudinal strain (GLS) and right ventricular global longitudinal strain were both significantly reduced in patient group (LV GLS ; -17,4% ,-19% p = 0,002 , RV GLS -19%, -24% p= 0,002 ). We found GWI and GCW were significantly lower in patients (mean 1549 mmHg% to 1800 mmHg%, p = 0,008) (mean 1857 mmHg% to 2176 mmHg%, p = 0,008), while GWW and MWE did not differ between the groups. We could not detect any significant correlation between MW indices and glomeruler filtration rate(GFR), time after surgery or hypertension. Conclusion Kidney donation may be associated with increased risk of subclinical cardiac dysfunctions. Myocardial Work might be a valuable diagnostic tool to detect subtle cardiac changes in this unique population.