The trajectory of renal function following mechanical circulatory support and subsequent heart transplantation

Aim Patients with advanced heart failure (HF) frequently suffer from renal insufficiency. The impact of durable mechanical circulatory support (MCS) and subsequent heart transplantation (HTx) on kidney function is not well described. Methods and results We studied patients with advanced HF who received durable MCS as bridge to transplantation (BTT) and underwent subsequent HTx at our centre between 1996 and 2018. Glomerular filtration rate (GFR) was measured by Cr-51-EDTA or iohexol clearance during heart failure work-up; 3-6 months after MCS; and 1 year after HTx. Chronic kidney disease (CKD) was classified according to KDIGO criteria based on estimated GFR. A total of 88 patients (46 +/- 15 years, 84% male) were included, 63% with non-ischaemic heart disease. The median duration of MCS-treatment was 172 (IQR 116-311) days, and 81 subjects were alive 1 year after HTx. Measured GFR increased from 54 +/- 19 during HF work-up to 60 +/- 16 mL/min/1.73 m(2) after MCS (P < 0.001) and displayed a slight but nonsignificant decrease to 57 +/- 22 mL/min/1.73 m(2) 1 year after HTx (P = 0.38). The trajectory of measured GFR did not differ between pulsatile and continuous flow (CF) pumps. Among patients 35-49 years and those who were treated in the most recent era (2012-2018), measured GFR increased following MCS implantation and subsequent HTx. Estimated GFR displayed a similar course as did measured GFR. Conclusions In patients with advanced heart failure, measured GFR improved after MCS with no difference between pulsatile and CF-pumps. The total study group showed no further increase in GFR following HTx, but in certain subgroups, including patients aged 35-54 years and those treated during the latest era (2012-2018), renal function appeared to improve after transplant.