The value of inflow inversion recovery MRI for the diagnosis of transplant renal artery stenosis: comparison with digital subtraction angiography

Background To date, few data on the assessment of transplant renal artery stenosis (TRAS) by using inflow inversion recovery (IFIR) are available. The aims of this study was to evaluate the feasibility of IFIR in the assessment of TRAS using Digital Subtraction Angiography (DSA) as the reference. Results We retrospectively assessed the IFIR of 195 transplant renal arteries. The IFIR images for 194/195 arteries were judged to be of excellent, good, or moderate quality, and 1/195 was not diagnostic. There were 100 arteries with TRAS, of which 27 were subjected to DSA. The stenosis percentages were divided into five grades. Using DSA images, the TRAS in 27 patients were estimated as grade 1 (2, 7.4%), grade 2 (8, 29.6%), grade 3 (10, 37.0%), grade 4 (7, 25.9%) and grade 5 (0, 0%). In comparison, the TRAS was shown to be grade 1 (1, 3.7%), grade 2 (8, 29.6%), grade 3 (9, 33.3%), grade 4 (9, 33%) and grade 5 (0, 0%) in the IFIR images. The nonparametric Wilcoxon signed-rank test was used to compare IFIR with DSA. In addition, a Bland–Altman plot was used to estimate the agreement between IFIR and DSA measurements. There was no significant difference between IFIR and DSA measurements (p < 0.05). Conclusions Relative to the reference DSA, IFIR was shown to be noninvasive, accurate for the diagnosis and evaluation of TRAS.

Long-term outcome of percutaneous transluminal renal angioplasty (PTRA) versus PTRA with stenting (PTRAS) in transplant renal artery stenosis

Background Endovascular treatment is standard of care for transplant renal artery stenosis (TRAS). No study has evaluated long-term outcomes compared between percutaneous transluminal renal angioplasty (PTRA) and PTRA with stenting (PTRAS). Accordingly, this study aimed to investigate the 1-year clinical success, and short- and long-term event-free survival between PTRA and PTRAS in patients diagnosed with TRAS at Thailand’s largest national tertiary referral center. Methods This single-center retrospective study included kidney transplant patients treated for TRAS during January 2001 to June 2019. Clinical success was defined as (1) increase in estimated glomerular filtration rate (eGFR) > 15%, or (2) reduction in mean arterial pressure (MAP) > 15% with no decrease in antihypertensive medication, or no reduction in MAP or reduction in MAP < 15% with decrease in antihypertensive medication. Incidence of kidney transplant graft failure and transplant renal artery stenosis were also collected. Results Sixty-five cases of TRAS were identified from 1072 patients who underwent kidney transplantation. The majority (98.5%) had end-to-side anastomosis technique. Thirty-four patients had PTRA, while 31 patients had PTRAS. One-year clinical success according to renal outcome and BP reduction was 78.5% and 49.2%, respectively. Both renal outcome (79.4% vs. 77.4%, p = 0.845) and BP reduction (40.6% vs. 58.1%, p = 0.166) at 1 year were similar between the PTRA and PTRAS groups. Compared between PTRA and PTRAS, event-free survival for composite of kidney transplant graft failure or transplant renal artery restenosis was significantly higher for PTRAS at 1 year (82.4% vs. 100%, p = 0.025), but not significantly different at 10 years (73.5% vs. 71%, p = 0.818). Conclusions We demonstrated the 1-year clinical success, and short- and long-term event-free survival between PTRA and PTRAS in TRAS patients. One-year clinical success was found to be similar between groups. Event-free survival for composite of kidney transplant graft failure or transplant renal artery restenosis was significantly higher in PTRAS at 1 year, but similar between groups at 10 years. Trial registration Thai Clinical Trials Registry, TCTR20200626002. Registered 26 June 2020—Retrospectively registered, http://www.clinicaltrials.in.th/index.php?tp=regtrials&menu=trial search&smenu = fulltext&task = search&task2 = view1&id = 6441