Renal vascular resistance is increased in patients with kidney transplant

• Published in: BMC nephrology 2019-11, Vol.20 (1), p.437-9, Article 437
• Main Authors: Päivärinta, Johanna, Oikonen, Vesa, Räisänen-Sokolowski, Anne, Tolvanen, Tuula, Löyttyniemi, Eliisa, Iida, Hidehiro, Nuutila, Pirjo, Metsärinne, Kaj, Koivuviita, Niina
• Format: Article
• Language: English
• Subjects: Biopsy; Biopsy - methods; Blood flow; Blood pressure; Brain; Care and treatment; Chronic kidney disease; Chronic kidney failure; Coronary vessels; Correlation of Data; Cross-Sectional Studies; Diagnostic imaging; Epidermal growth factor receptors; Female; Fibrosis; Histochemistry; Histology; Humans; Kidney biopsy; Kidney diseases; Kidney Failure, Chronic - surgery; Kidney Function Tests - methods; Kidney transplant; Kidney transplantation; Kidney Transplantation - adverse effects; Kidney Transplantation - methods; Kidney transplants; Laboratories; Long Term Adverse Effects - diagnosis; Long Term Adverse Effects - physiopathology; Male; Middle Aged; Nephrology; NMR; Novels; Nuclear magnetic resonance; Organ transplantation; Perfusion; Perfusion Imaging - methods; Positron emission tomography; Positron-Emission Tomography - methods; Renal Circulation; Renal perfusion; Retrospective Studies; Statistical analysis; Surgery; Tomography; Transplants & implants; Transplants - blood supply; Transplants - diagnostic imaging; Transplants - pathology; Vascular Resistance; Velocity
• ISSN: 1471-2369; 1471-2369
• DOI: 10.1186/s12882-019-1617-2

Despite improvement in short-term outcome of kidney transplants, the long-term survival of kidney transplants has not changed over past decades. Kidney biopsy is the gold standard of transplant pathology but it's invasive. Quantification of transplant blood flow could provide a novel non-invasive method to evaluate transplant pathology. The aim of this retrospective cross-sectional pilot study was to evaluate positron emission tomography (PET) as a method to measure kidney transplant perfusion and find out if there is correlation between transplant perfusion and histopathology. Renal cortical perfusion of 19 kidney transplantation patients [average time from transplantation 33 (17-54) months; eGFR 55 (47-69) ml/min] and 10 healthy controls were studied by [ O]H O PET. Perfusion and Doppler resistance index (RI) of transplants were compared with histology of one-year protocol transplant biopsy. Renal cortical perfusion of healthy control subjects and transplant patients were 2.7 (2.4-4.0) ml min  g and 2.2 (2.0-3.0) ml min  g , respectively (p = 0.1). Renal vascular resistance (RVR) of the patients was 47.0 (36.7-51.4) mmHg mL min g and that of the healthy 32.4 (24.6-39.6) mmHg mL min g (p = 0.01). There was a statistically significant correlation between Doppler RI and perfusion of transplants (r = - 0.51, p = 0.026). Transplant Doppler RI of the group of mild fibrotic changes [0.73 (0.70-0.76)] and the group of no fibrotic changes [0.66 (0.61-0.72)] differed statistically significantly (p = 0.03). No statistically significant correlation was found between cortical perfusion and fibrosis of transplants (p = 0.56). [ O]H O PET showed its capability as a method in measuring perfusion of kidney transplants. RVR of transplant patients with stage 2-3 chronic kidney disease was higher than that of the healthy, although kidney perfusion values didn't differ between the groups. Doppler based RI correlated with perfusion and fibrosis of transplants.