Clinical and prognostic value of TAMX index of interlobar arteries of the middle segment in patients after allograph kidney transplantation in the late postoperative period

Abstract

Introduction. Kidney transplantation has become the best treatment for patients with end-stage of chronic renal failure. The issues of studying the causes and mechanisms of the development of renal transplant dysfunction in the late postoperative period, the search for high-precision minimally invasive methods for early diagnosis of renal transplant dysfunction remain relevant, since this largely determines the further normal functioning of the organ and prognosis for the patient.The aim of the study was to investigate the clinical and prognostic value of the time-averaged peak velocity (TAMX) index of the interlobar arteries of the middle segment in patients after allograft transplantation in the long-term postoperative period.Material and research methods. For the period 2014-2015 ultrasound scan of renal grafts were performed in 26 patients with creatinine levels within the normative values. The average age of recipients in this group was 31.4 ± 1.67 years. Among the recipients there were 15 men (57.7%), 11 women (42.3%). Living related kidney transplantation (LRKT) were performed in 61.54% of patients, in 38.46% – cadaveric kidney transplantation (CKT). In all patients, the plasma creatinine level met the standard value or exceeded them by no more than 25%, fluctuating on average from 94 to 130 μmol / L, averaging 114.5 ± 3.85 μmol / L.The second study is based on the results of ultrasound scan of renal transplants in 26 patients with creatinine levels exceeding the standard values for the period 2015-2016. The average age of recipients in this group was 38.99 ± 2.32 (34.35-43.62) years. There were 14 men (53.84%) among the recipients, and 12 women (46.16%). LRKT were performed in 6 patients, in 20 – CKT. In all patients the plasma creatinine level was above normal values, fluctuating on average from 155 to 629 μmol / L, averaging 259.46 ± 35.33 μmol / L. The groups were comparable in terms of the main clinical and demographic parameters.Results. The method for predicting complications by the level of TAMX of the interlobar arteries of the middle segment of the kidneys during Doppler ultrasonography of the renal blood flow (<15 cm / s) has a fairly high sensitivity (83.87%), specificity (79.31%), positive and negative predictive significance (81.25% and 82.14%, respectively) in the diagnosis of a high risk of developing late nephrodysfunction in recipients after organ transplantation. Recipients with allograft with a TAMX level of interlobar arteries (middle segment) of more than15 cm / s, as a result of our examination, had a serum creatinine level 2.35 times less, and the glomerular filtration rate is almost 2 times higher than similar indicators in patients with a TAMX level less15 cm / s (p <0.01), which confirms the presence of more expressive manifestations of chronic allograft dysfunction.The interdependence between the TAMX of the interlobar arteries of the middle segment and serum creatinine, which is gradually regressing in a parabola, shows that more than half of the entire variance of the creatininemia sign can be associated with a change in the TAMX indicator (as a sign of deterioration in the renal blood flow of the graft), and the largest "failure" of the function were observed in the range from 12 to15 cm/ s TAMX, where in the overwhelming majority of cases (about 80%) there were impaired renal hemodynamics and the available laboratory markers of impaired renal function (creatinine above 200 μmol / l).Conclusions. A reliable prognostic value of TAMX of interlobar arteries (middle segment) was shown in spectral Doppler ultrasonography of renal blood flow in a priori assessment of the risk of developing post-transplant nephropathy, which allows us to consider it as a cumulative predictor of an unfavorable prognosis and a potential factor not only for the formation of graft dysfunction, but also for rejection in the late postoperative period.

Keywords

• logistic regression
• late graft dysfunction
• pulsation index
• wald test
• doppler ultrasound