Who should have pelvic vessel imaging prior to renal transplantation?

The influence of simultaneous pancreas-kidney transplantation on the evolution of diabetic foot lesions and peripheral arterial disease

PURPOSE

Simultaneous pancreas-kidney transplantation (SPKT) remains the best treatment option in patients with type 1 diabetes and chronic kidney failure. There are only a few studies addressing the potential ischemic deterioration of peripheral arterial disease (PAD) due to blood diverting from the iliac artery to the kidney graft. We aimed to evaluate diabetic foot lesions and PAD evolution in SPKT recipients and investigate if they are more frequent in ipsilateral lower limb of kidney graft.

METHODS

We developed a retrospective cohort, including patients submitted to SPKT in our tertiary center, between 2000 and 2017. Diabetic foot lesions and PAD frequencies were compared in the period before and after transplantation.

RESULTS

Two hundred and eleven patients were included, 50.2% (n = 106) female, with a median age at transplantation of 35 years (IQR 9). After a median follow-up period of 10 years (IQR 7), patient, kidney, and pancreatic graft survival were 90.5% (n = 191), 83.4% (n = 176), and 74.9% (n = 158), respectively. Before transplant, 2.8% (n = 6) had PAD and 5.3% (n = 11) had history of foot lesions. In post-transplant period, 17.1% (n = 36) patients presented PAD and 25.6% (n = 54) developed diabetic foot ulcers, 47.6% (n = 35) of which in the ipsilateral and 53.3% (n = 40) in the contralateral lower limb of the kidney graft (p = 0.48). Nine patients (4.3%) underwent major lower limb amputation, 3 (30%) ipsilateral and 7 (70%) contralateral to the kidney graft (p = 0.29).

CONCLUSIONS

Diabetic foot lesions were not more frequent in the ipsilateral lower limb of the kidney graft, therefore downgrading the 'steal syndrome' role in these patients.

Rate of Ipsilateral Chronic Limb-Threatening Ischemia (CLTI) After Kidney Transplantation: A Retrospective Single-Center Study

Objective: To analyze whether the rate of lower extremity (LE) ischemia is higher on the ipsilateral side after kidney transplantation.

Methods: Our institutional transplant database was retrospectively queried for all patients who received a kidney transplant and underwent subsequent LE revascularization or major limb amputations between January 2004 and July 2020. The one-sample binomial test was used to test whether the LE ipsilateral to the transplanted kidney was at higher risk of peripheral arterial disease (PAD) complications necessitating intervention (major amputation or revascularization).

Results: There were 1,964 patients who received a kidney transplant during the study period. Of these, 51 patients (3%) had subsequent LE arterial revascularizations or major amputations. The mean age was 58 ± 10 years, and 37 patients (73%) were male. A total of 33 patients had ipsilateral LE vascular interventions (26 major amputations and seven revascularizations) while 18 patients had contralateral vascular interventions (14 major amputations and four revascularizations) (P = 0.049). The average interval between transplantation and subsequent vascular intervention was 52 months for the ipsilateral intervention group and 41 months for the contralateral intervention group (P = 0.33).

Conclusions: In patients who received kidney transplantation and required subsequent LE surgical intervention, we observed an association between the side of transplantation and the risk of future ipsilateral LE arterial insufficiency. Further studies are needed to determine the etiology of this association.

Distribution of Iliac Artery Calcification on Unenhanced Computed Tomography Scans Performed on Potential Recipients Prior to Renal Transplantation

PURPOSE

To investigate whether a significant difference exists between the calcification of the common iliac arteries (CIAs) and the external iliac arteries (EIAs) and test for associations between clinical factors and the distribution of calcification.

METHODS

A retrospective review of renal transplant candidates who underwent a routine preoperative unenhanced computed tomography yielded 214 patients. Agatston scores for the patients' left CIA, left EIA, right CIA, and right EIA were assigned. A retrospective search of patient records screened for 5 clinical factors (diabetes, hypertension, coronary artery disease [CAD], smoking, and dialysis). Data were assessed using a 2-sided t test, odds ratio, and a multivariate linear regression calculated through generalized estimating equation (GEE).

RESULTS

The log-transformed Agatston scores in the CIA were found to be significantly greater than that in the EIA (t = 9.57, P < .0001), with a mean difference of 1.5078 (95% confidence interval: 1.1962-1.8194), indicating relative EIA sparing. There were no significant differences in calcification between the right and left sides. Generalized estimating equation found that CAD and smoking demonstrated independent positive associations with EIA sparing (GEE = 2.6464 [P = .0197] and 1.9092 [P = .0470], respectively). Age was also significantly associated and indicated that EIA sparing remained relatively constant throughout patients' lives (GEE = 1.0711 [P < .0001]).

CONCLUSION

This study has demonstrated statistically significant EIA sparing in end-stage renal disease patients and identified CAD and smoking as associated factors. This phenomenon warrants further investigation into its biological mechanisms and the impact of EIA sparing on outcomes following transplants.

Preoperative planning of renal transplantation: a comparison of non-contrast-enhanced ultrasonography, computed tomography, and magnetic resonance angiography with observations from surgery

BACKGROUND

Many candidates for kidney transplantation need to undergo vessel examination before the transplantation procedure.

PURPOSE

To identify the optimal preoperative modality for the examination of vessel status without the use of contrast agents in kidney transplant candidates.

MATERIAL AND METHODS

Fifty-three consecutive patients were examined and 31 patients were transplanted. Ultrasonography (US), non-contrast-enhanced computed tomography (NCCT), and non-contrast-enhanced magnetic resonance angiography (NCMRA) were compared using inspection during kidney transplantation (TX) as a reference standard. The sensitivity and specificity to severe arteriosclerotic changes and the accuracy were calculated. Kappa statistics were used to assess the agreement between TX and the different examination modalities, and McNemar's test was used to test for significant differences.

RESULTS

US had higher sensitivity (1.0) and better agreement with observations from surgery (k = 0.89) than both NCCT (sensitivity = 0.60; k = 0.72) and NCMRA (sensitivity = 0.20; k = 0.30). No significant difference was found between TX and US (P = 0.3173) or TX and NCCT (P = 0.1573), but there was a significant difference between TX and NCMRA (P = 0.0455). US was inconclusive in 20% of cases, and the internal iliac artery could not be visualized in 69% of cases.

CONCLUSION

Either US or NCCT can be used as the preferred preoperative imaging modality to examine vessel status before kidney transplantation, but a combination of the two is preferable. NCMRA should not be used as the sole imaging modality for preoperative imaging before kidney transplantation because of its low sensitivity in detecting severe arteriosclerotic disease without the presence of stenosis.

Does kidney transplantation to iliac artery deteriorate ischemia in the ipsilateral lower extremity with peripheral arterial disease?

Objectives

This study was conducted to investigate the progression of lower extremity ischemia following kidney transplantation to iliac artery in patients with peripheral arterial disease.

Methods

A retrospective chart review of all renal transplant patients completed at a university teaching medical center from January 2006 to December of 2011 was performed. A total of 219 patients underwent successful kidney transplantation to the common, external, or internal iliac artery. Pre- and post-transplantation ischemic changes in the ipsilateral lower extremity were reviewed and analyzed.

Results

Thirty-eight of the 219 patients had ipsilateral peripheral arterial disease and seven of them were symptomatic. Six of the seven symptomatic patients remained stable and one patient’s rest pain improved, postoperatively. Eight patients developed new symptoms of ischemia 12 months later, including four with claudication, two with ischemic ulcers, and two with gangrene toes. The ulcers were healed following superficial femoral artery stenting and wound care. Toe amputation was performed in two patients with gangrene. No major amputation was required up to 48 months of follow-up.

Conclusions

Transplanted kidney to iliac artery does not significantly deteriorate ischemia in adults with ipsilateral lower extremity peripheral arterial disease. Late developed ischemic complications may be due to the progression of underlying arterial disease.

The prognostic significance of iliac vessel calcification in renal transplantation

BACKGROUND

Peripheral vascular disease and major extremity amputation are common in patients with established renal failure and are associated with considerable morbidity. Several studies have shown high rates of amputation following simultaneous pancreas-kidney transplantation, but there is minimal literature on the incidence of amputation following renal transplantation. Furthermore, there is little evidence regarding the best method of predicting which patients might be at risk of developing peripheral vascular complications after transplantation.

METHODS

We undertook a 5 year follow-up on the cohort of patients who were on our renal transplant waiting list 5 years ago (January 2007). At this time, it was standard practice within our unit for all patients to have routine pelvic x-rays to assess for vascular calcification of the iliac vessels at the time of activation onto the transplant waiting list. Any patients with moderate/severe calcification on x-ray, which may complicate transplantation, were referred for computed tomography angiogram (CTA) of their aorto-iliac vessels. Mortality, transplantation outcomes, and amputation rates at 5 years were correlated with the severity of calcification on preoperative imaging.

RESULTS

One hundred eighty-seven patients were on the waiting list for renal transplantation in January 2007 (92 men; mean age, 58.3 +/- 6.2 years). Ninety-three patients received a transplant during the subsequent 5 years. By January 2012, 82 patients had a functioning transplant, 45 remained on the waiting list (5 suspended), 40 patients had died, and 20 were alive but no longer on the waiting list. Seventy-three (39.5%) had moderate or severe calcification on plain x-ray and went on to have CTA. Of these patients, 16 (21.9%) had extensive calcification affecting all the iliac vessels and were removed from the waiting list as a result. Preoperative imaging was useful in determining the side for surgery in a further 18 patients (24.3%). Twenty-two patients developed vascular complications. Nineteen (86.4%) had moderate-severe vascular calcification on imaging. Four of the patients with vascular complications (18.2%) underwent transplantation (2 had below knee amputation (BKA) prior to transplantation; 1 developed distal ischemia on the same side as the transplantation 2 years postoperatively; 1 had bilateral above knee amputation (AKA) approximately 2 years after transplantation). Eleven (50%) of the patients with vascular complications were dead at 5 years of follow-up. Mortality and amputation rates were higher in patients with moderate-severe calcification than minimal calcification (30.1% vs 16.6%; P = .02 and 10.9% vs 1.8%; P = .003, respectively). There was no difference in rates of delayed graft function (DGF), biopsy-proven acute rejection (BPAR), or creatinine at 1 year between patients who underwent transplantation with moderate-severe calcification and those without, however, intraoperative vascular complications (26.7% vs 3%; P < .001), graft loss (28.1% vs 3.4%; P = .01), and death with a functioning transplant (9.7% vs 1.6%; P = .04) rates were higher in patients with extensive calcification compared with those without.

CONCLUSIONS

Plain x-ray of the pelvis is a useful screening tool to identify those patients who may require further detailed vascular imaging prior to transplantation. Amputation rates following renal transplantation are low and peripheral vascular disease (PVD) in isolation should not preclude transplantation. Nevertheless, significant vascular calcification is predictive of mortality both with and without transplantation and graft loss in patients with a renal transplant.