Junarta J. BMC Cardiovasc Disord. 2020 Jan 8;20(1):6.
Patients with chronic kidney disease (CKD) who are kidney transplant recipients have a greater burden of cardiovascular disease (CVD). Even though cardiovascular risk factors improve in the instantaneous perioperative period, the long-term risk remains inflated. In transplant patients with a surviving graft, CVD is the commonest cause of death as compared to infection or malignancy.
In stable kidney transplant patients, endothelial dysfunction, arterial stiffness, and increased atherosclerosis are common and may be potential factors leading to high cardiovascular event rate. The nature of the changes in these vascular abnormalities in kidney transplant recipients is not known. Previous studies mostly analysed changes in the vascular properties of transplant patient’s pre-transplantation and instantaneously post-transplantation and did not analyse changes in stable transplant recipients long after transplantation. If these changes are unfavourable, it may be due to high cardiovascular event rate and the result of different post-transplantation risk factors. Thus, Junarta J et al., conducted a study to examine the changes in endothelial dysfunction, arterial stiffness, and atherosclerosis in stable kidney transplant recipients long into the post-transplant period.
Candidates included patients recruited from the transplantation clinic, patient relatives, and staff volunteers. Patients were entitled if they were among 18 to 80 years of age with stable kidney function for ≥3 months (eGFR change < 5 ml/ min/1.73m2) and have undergone transplantation for ≥6 months with or without previous dialysis. 18 kidney transplant patients and 17 healthy volunteers were enlisted in the study. 161 ± 36 days was the mean number of days between the first and second visit for transplant patients and 185 ± 52 days for controls. 29 ± 14 months (median 29, IQR 28) was the mean duration on dialysis (haemodialysis and/or peritoneal dialysis) before transplantation. The median time following transplantation was 86 months at recruitment with an IQR of 123 months. At recruitment, transplant patients were on 3 of 6 various immune-suppressants. In a quiet vascular laboratory with a controlled temperature of 22–24°C, vascular parameters were estimated at recruitment (baseline visit) and at 3–6 months following recruitment (second visit). Vascular parameters estimated comprised brachial flow-mediated dilation (FMD), nitroglycerin-mediated dilation (NMD), carotid-femoral pulse wave velocity (cf-PWV), and common carotid artery intima-media thickness (CCA-IMT). Participants were required to withhold anti-hypertensive medications 24 h before vascular evaluation to inhibit intervention.
In transplant patients, FMD was reduced (− 1.52 ± 2.74; p = 0.03), cf-PWV was enhanced (0.62 ± 1.06; p = 0.03), and CCA-IMT was enhanced (0.35 ± 0.53; p = 0.02) [Table 1]. No changes were noticed in controls. Among transplant patients and controls, there was no difference in age (51 ± 13 vs. 46 ± 11; p = 0.19), body mass index (26 ± 5 vs. 25 ± 3; p = 0.49), serum cholesterol (4.54 ± 0.96 vs. 5.14 ± 1.13; p = 0.10), systolic blood pressure (BP) (132 ± 12 vs. 126 ± 12; p = 0.13), diastolic BP (82 ± 9 vs. 77 ± 8; p = 0.10), or diabetes status (3 vs. 0; p = 0.08).
Changes in FMD was correlated with baseline haemoglobin (r = 0.52, p = 0.03), corrected calcium (r = 0.61, p = 0.01), and transferrin (r = 0.53, p = 0.03). However, they were not correlated with age (r = 0.43; p = 0.08), BMI (r = 0.45; p = 0.05), WHR (r = 0.31; p = 0.21), gender (rpb = − 0.18; p = 0.48), DM (rpb = 0.18; p = 0.47), SBP (r = − 0.32; p = 0.07), diastolic BP (DBP) (r = − 0.03; p = 0.89). Changes in PWV was correlated with baseline transferrin (r = 0.52, p = 0.030 however, changes in cf-PWV were not correlated with age (r = 0.18; p = 0.49), BMI (r = 0.27; p = 0.29), WHR (r = 0.14; p = 0.57), gender (rpb = 0.16; p = 0.54), DM (rpb = − 0.14; p = 0.59), SBP (r = 0.30; p = 0.08), or DBP (r = 0.08; p = 0.64). Changes in CCA-IMT were correlated with baseline phosphate (r = 0.67, p < 0.01) however they were not correlated with age (r = − 0.10; p = 0.71), BMI (r = − 0.08; p = 0.78), WHR (r = − 0.29; p = 0.26), gender (rpb = 0.14; p = 0.59), DM (rpb = − 0.25; p = 0.34), SBP (r = 0.23; p = 0.19), or DBP (r = 0.04; p = 0.81).
Thus, it was concluded that markers of vascular structure and function aggravate during the long-term follow-up in the post-transplant duration, which may show continued elevated cardiovascular occurrence rates in this population.
Table 1: Changes in cardiovascular structure and function from baseline to second visit
IQR: Interquartile Range; eGFR: estimated Glomerular Filtration Rate
