Risk of post-transplant cardiovascular events in kidney transplant recipients with preexisting aortoiliac stenosis

Assessment of aortic and iliac artery calcification using CT-angiography in kidney transplant candidates

PURPOSE

Assessment of vascular calcification provides the opportunity for risk stratification in kidney transplant candidates (KTCs), as vascular calcification constitutes an independent risk factor for cardiovascular events. The aim of the present study is to explore the feasibility of contrast enhanced computed tomography (CT)-angiography to quantitate vascular calcification, to avoid the extra radiation of an additional non-contrast CT scan.

METHODS AND MATERIALS

43 KTCs who underwent concomitant non-contrast CT scans and CT-angiographies of the infrarenal aorta and iliac arteries were included. Vascular calcification was quantified using the Agatston method on non-contrast CT and applying individual Hounsfield Unit thresholds on CT-angiographies based on the radio density of the aortic lumen. The calcium scores and volumes from non-contrast CT scans and CT-angiographies were compared using linear regression and Bland-Altman plots.

RESULTS

Non-contrast CT revealed vascular calcification in the infrarenal aorta in 92% of KTCs and in the iliac arteries in 90% of KTCs. The calcium scores estimated from CT-angiography correlated linearly with the calcium scores based on non-contrast CT scans (infrarenal aorta: R2 = 0.71, p < 0.0001; iliac arteries: R2 = 0.71, p < 0.0001); however, the calcium scores were higher, and volumes were lower compared to the non-contrast CT scans. The median differences in calcium scores were 1517 [48 - 6138] for the infrarenal aorta, and 2361 [59 - 8644] for the iliac arteries.

CONCLUSION

Vascular calcification is present in the majority of KTCs. Calcification of the infrarenal aorta and iliac arteries may be assessed using CT-angiography, though higher calcium scores and lower volumes are found compared to the non-contrast CT scan.

Kidney Donor Risk Index and Cardiovascular Complications in a Long-Term Follow-Up Observation

Background: The suitability of the Kidney Donor Risk Index (KDRI) has not been fully validated in the European population. The aim of this study was to evaluate the value of the KDRI in predicting kidney graft function and cardiovascular events (CVEs) in a Polish cohort of kidney transplant recipients (KTRs). Methods: In this retrospective study kidney graft function and CVEs were analyzed among 1420 patients transplanted between 1999 and 2017 and followed until 2021. The KDRI was calculated according to the formula proposed by Rao. Patients were assigned into quartiles (Qs) of KDRI values. Results: Patients in Q4 were older, with higher BMI, longer cold ischemia time (CIT), and a greater rate of ischemic heart disease at the transplantation. The KDRI value determined both early and long-term graft function. During a median follow-up period of 91 months, at least one cardiovascular event was noted in 227 (16.0%) kidney transplant recipients. There was a significant increasing trend for the occurrence of post-transplant CV complications along the consecutive KDRI quartiles (χ2 = 7.3; p < 0.01) among kidney transplant patients younger than 50 years at the time of transplantation. Conclusions: The KDRI is an adequate prognostic tool also for the European population. Despite the KDRI not being used for allocation in Poland we found that kidneys with a higher KDRI are allocated to recipients with worse survival prognosis. The quality of kidneys from a deceased donor may be related to the occurrence of post-transplant cardiovascular complications in recipients younger than 50 years at the transplantation, including those without history of comorbidities such as diabetes or cardiovascular disease.

Systematic, Pretransplant Screening by Aortoiliac CT Angiography: Impact on Surgical Decision-making and Clinical Outcomes

Background

Aortoiliac screening before kidney transplantation is suggested by some guidelines to select patients for transplantation and to assist surgical planning. We investigated the clinical outcomes of systematic screening for aortoiliac disease in potential kidney transplant candidates.

Methods

In this observational study, 470 potential kidney transplant candidates underwent aortoiliac computed tomography angiography. Patients were characterized by the presence of peripheral artery disease and calcification of iliac arteries and aortoiliac arteries. The risk of graft loss and graft function at 1 y posttransplant were examined and clinical decisions based on the vascular findings were assessed.

Results

Clinically diagnosed peripheral artery disease was present in 66 patients (14%), circular calcifications in 101 patients (21%), and aortoiliac stenosis in 77 patients (16%). In 326 patients undergoing kidney transplantation, circular calcification or aortoiliac stenosis was not associated with an increased risk of graft loss (P = 0.45 and P = 0.28) or estimated glomerular filtration rate (P = 0.23 and P = 0.76) at 1 y posttransplant. When evaluated for transplantability, clinical decision-making based on vascular findings was recorded in 67 of 429 patients (16%), including rejection for transplantation in 7 patients (2%) and laterality for surgical implantation in 52 patients (12%).

Conclusions

Systematic screening by aortoiliac computed tomography angiography may assist in surgical planning but seems of limited clinical value in assessing the risk of future graft loss and graft function in patients undergoing kidney transplantation.

Safety and efficacy of kidney transplantation in patients with aortoiliac stenosis: a retrospective cohort study

BACKGROUND

The impact of aortoiliac occlusive disease on kidney transplantation remains unclear. This study aims to investigate the clinical outcomes of kidney transplant patients with aortoiliac atherosclerotic stenosis.

METHODS

Retrospective data from our transplant center were used to identify patients undergoing kidney transplantation between January 2010 and December 2020. Aortoiliac atherosclerotic stenosis was screened and stratified by the Trans-Atlantic Inter-Society Consensus (TASC) II classification. The primary outcome was patient survival. Secondary outcomes were 90-day mortality, death-censored graft survival, graft function, and arterial complications. Propensity score matching was used to match all patients in the stenosis group with patients without stenosis sharing similar characteristics.

RESULTS

The analysis included 655 patients, 524 without stenosis and 131 with aortoiliac stenosis (95 with TASC A/B stenosis and 36 with TASC C/D stenosis). Recipient age [median (IQR), 66 (60-70) vs. 66 (59-71) years; P =0.47], sex [male: 87 (66%) vs. 355 (68%), P =0.85], and comorbidities were comparable between the stenosis and no-stenosis groups. Forty-six (35%) patients with stenosis were symptomatic. Patient survival was significantly lower in the stenosis group compared with the no-stenosis group (TASC A/B: 30.6% vs. no-stenosis: 44.1%, P =0.013; TASC C/D: 11.4% vs. no-stenosis: 44.1%, P <0.001). The incidence rates of artery dissection, lower extremity ischemia, and acute thrombosis were significantly higher in the stenosis group ( P <0.001). However, death-censored graft survival (TASC A/B: 73.6% vs. no-stenosis: 72.9%, P =0.62; TASC C/D: 58.1% vs. no-stenosis: 72.9%, P =0.16) and graft function were comparable between the groups.

CONCLUSIONS

Aortoiliac atherosclerotic stenosis significantly impacts patient survival but not graft survival. Our analyses suggest that patients with TASC A/B stenosis have prolonged survival and enhanced quality of life through kidney transplantation. However, for patients with TASC C/D stenosis, kidney transplantation improves quality of life without bringing survival benefits.