Consequences of Iliac Arterial Atheroma on Renal Transplantation

Lower Extremity Peripheral Arterial Disease and Its Relationship with Adverse Outcomes in Kidney Transplant Recipients: A Retrospective Cohort Study

The purpose of the study was to characterize lower extremity peripheral arterial disease (LEPAD) in a series of kidney transplant patients and to assess the impact on adverse outcomes. A retrospective cohort study was conducted including kidney transplant recipient patients who underwent screening for LEPAD. The outcomes evaluated were classified as perioperative and post-transplant, including cardiovascular events, amputation, mortality, and loss of the graft. A total of 141 renal transplant patients screened for LEPAD were identified, with an average follow-up of 3 years. LEPAD occurred in 14.2% (20/141). No differences in cardiovascular risk factors were found between the groups, except for smoking (45% vs. 24%, p < 0.05). In the group with LEPAD, the most compromised anatomical segment was the infrapopliteus, with no iliac involvement found. The Cox proportional hazards model indicated that the variables age, gender, and weight were significant in patients with LEPAD. There were no differences between the groups in terms of graft loss and death. The infrapopliteal segment is the area of greatest stenosis in kidney transplant patients with LEPAD. Together with smoking, they can explain the presence of major amputations in kidney transplant patients; however, they had no impact on graft functionality or death.

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

Prediction of the risk of cardiovascular events (CVE's) is important to optimize outcomes after kidney transplantation. Aortoiliac stenosis is frequently observed during pre‐transplant screening. We hypothesized that these patients are at higher risk of post‐transplant CVE's due to the joint underlying atherosclerotic disease. Therefore, we aimed to assess whether aortoiliac stenosis was associated with post‐transplant CVE's. This retrospective, single‐center cohort study included adult kidney transplant recipients, transplanted between 2000 and 2016, with contrast‐enhanced imaging available. Aortoiliac stenosis was classified according to the Trans‐Atlantic Inter‐Society Consensus (TASC) II classification and was defined as significant in case of ≥50% lumen narrowing. The primary outcome was CVE‐free survival. Eighty‐nine of 367 patients had significant aortoiliac stenosis and were found to have worse CVE‐free survival (median CVE‐free survival: stenosis 4.5 years (95% confidence interval (CI) 2.8–6.2), controls 8.9 years (95% CI 6.8–11.0); log‐rank test P < .001). TASC II C and D lesions were independent risk factors for a post‐transplant CVE with a hazard ratio of 2.15 (95% CI 1.05–4.38) and 6.56 (95% CI 2.74–15.70), respectively. Thus, kidney transplant recipients with TASC II C and D aortoiliac stenosis require extensive cardiovascular risk management pre‐, peri,‐ and post‐transplantation.

Utility of a Simplified Iliac Artery Calcium Scoring System to Guide Perioperative Management for Renal Transplantation

Non-contrast computed tomography scans of the abdomen and pelvis (CTAP) are often obtained prior to renal transplant to evaluate the iliac arteries and help guide surgical implantation. The purpose of this study was to describe the association of iliac calcification scores with operative and clinical outcomes using a simplified scoring system. A retrospective review of 204 patients who underwent renal transplant from 1/2013 to 11/2014 and who had a CTAP within 3 years prior to transplant was performed. Data were collected from the electronic medical record. Common iliac artery (CIA) and external iliac artery (EIA) calcification on CTAP were assessed using a simple scoring system. Descriptive statistics, logistic regression, and survival analyses were performed. A total of 204 patients were included in the analysis. The mean age was 57.4 ± 11.2 years and 134/204 (66%) were men. Nineteen patients (9%) had a history of peripheral artery disease (PAD), 78 (38%) had coronary artery disease, and 22 (11%) had a previous cerebrovascular accident (CVA). Patients with severe right EIA plaque morphology were significantly more likely to require arterial reconstruction compared to those without severe plaque (3/14[21%] 4/153 [3%], p = 0.03). Eleven patients (5%) had one or more amputations (toe, foot, or transtibial) following transplant. In UV logistic regression, severe EIA plaque morphology (OR 8.1, CI 2.2–29.6, p = 0.002) and PAD (OR 10.7, CI 2.8–39.9, p = 0.0004) were associated with increased odds of amputation. In the MV model containing both variables, EIA plaque morphology (OR 4.4, CI 0.99–18.3, p = 0.04) and PAD (OR 6.3, CI 1.4–26.4, p = 0.01) remained independently associated with increased odds of amputation. Over a median follow up of 3.3 years (IQR 2.9–3.6), 21 patients (10%) had post-operative major adverse cardiac events (MACE, defined as myocardial infarction, coronary intervention, or CVA), and 23 patients died (11%). In unadjusted Kaplan Meier analysis, CIA plaque (p = 0.00081) and >75% CIA length calcification (p = 0.0015) were significantly associated with MACE. Plaque burden in the EIA is associated with increased need for intra-operative arterial reconstruction and post-operative lower extremity amputations, while CIA plaque is associated with post-operative MACE. Assessment of CIA and EIA calcification scores on pre-transplant CT scans in high risk patients may guide operative strategy and perioperative management to improve clinical outcomes.

Endarterectomy for Iliac Occlusive Disease during Kidney Transplantation: A Multicenter Experience

Little is known about the surgical challenges and outcomes of kidney transplantation (KT) in the face of severe iliac occlusive disease (IOD). We aim to examine our institution's experience and outcomes compared with all KT patients. Retrospective review of our multi-institutional transplant database identified patients with IOD requiring vascular surgery involvement for iliac artery endarterectomy at time of KT from 2000 to 2018. Clinical data, imaging studies, and surgical outcomes of 22 consecutive patients were reviewed. Our primary end-point was allograft survival. Secondary end-points included mortality and perioperative complications. A total of 6,757 KT were performed at our three sites (Florida, Arizona, and Minnesota); there were 22 (0.32%) patients receiving a KT with concomitant IOD requiring iliac artery endarterectomy. Mean patient age was 61.45 ± 7 years. There were 13 (59.1%) male patients. The most common etiology of renal failure was diabetic nephropathy in 10 patients (45.5%) followed by a combination of hypertensive/diabetic nephropathy in five patients (22.7%), and hypertensive nephrosclerosis in three patients (13.6%). The majority ( n  = 16, 72.7%) of patients received renal allografts from deceased donors and six (27.3%) were recipients from living donors. Mean time from dialysis to transplantation was 2.9 ± 2.9 years. Mean follow-up was 3.5 ± 2.5 years. Mean length of hospital stay was 6.3 ± 4.3 days (range: 3-18 days). Graft loss within 90 days occurred in two (9.1%) patients, one due to renal vein thrombosis and another due to acute tubular necrosis. Overall allograft survival was 90.1% at 1-year and 86.4% at 3-year follow-up. Overall mortality occurred in 6 (27.3%) patients. Perioperative complications (Clavien-Dindo Grade 2-4) occurred in 13 (59.1%) patients, including 10 (45.5%) with acute blood loss anemia requiring transfusion, 2 (9.1%) reoperations for hematoma evacuation, 1 (4.5%) ischemic colitis requiring total abdominal colectomy, and 1 (4.5%) renal vein thrombosis requiring nephrectomy. IOD patients selected for KT are not common and although challenging, they have similar outcomes to our standard KT patients. The 1- and 3-year allograft survivals were 90.1 and 86.4% versus 96.0 and 90.3% in the general KT patient population. With these excellent outcomes, we recommend expanding the criteria for KT to include patients with IOD with prior vascular surgery consultation to prevent progression of IOD or prevention of wait list removal in select patients who are otherwise good candidates for KT.

Impact of Aortoiliac Stenosis on Graft and Patient Survival in Kidney Transplant Recipients Using the TASC II Classification

BACKGROUND

Patients with end-stage renal disease and aortoiliac stenosis are often considered ineligible for kidney transplantation, although kidney transplantation has been acknowledged as the best therapy for end-stage renal disease. The clinical outcomes of kidney transplantation in patients with aortoiliac stenosis are not well-studied. This study aimed to assess the impact of aortoiliac stenosis on graft and patient survival.

METHODS

This retrospective, single-center study included kidney transplant recipients transplanted between January 1, 2000, and December 31, 2016, who received contrast-enhanced imaging. Patients with aortoiliac stenosis were classified using the Trans-Atlantic Inter-Society Consensus (TASC) II classification and categorized as having TASC II A/B lesions or having TASC II C/D lesions. Patients without aortoiliac stenosis were functioning as controls.

RESULTS

A total number of 374 patients was included in this study (n = 88 with TASC II lesions, n = 286 as controls). Death-censored graft survival was similar to the controls. Patient and uncensored graft survival was decreased in patients with TASC II C/D lesions (log-rank test P < 0.001). Patients with TASC II C/D lesions had a higher risk of 90-day mortality (hazard ratio, 3.96; 95% confidence interval, 1.12-14.04). In multivariable analysis, having a TASC II C/D lesion was an independent risk factor for mortality (hazard ratio, 3.25; 95% confidence interval, 1.87-5.67; P < 0.001). Having any TASC II lesion was not a risk factor for graft loss (overall P = 0.282).

CONCLUSIONS

Kidney transplantation in patients with TASC II A/B is feasible and safe without increased risk of perioperative mortality. TASC II C/D decreases patient survival. Death-censored graft survival is unaffected.

Targeting Vascular Calcification in Chronic Kidney Disease

Cardiovascular (CV) disease remains an important cause of morbidity and mortality for patients with chronic kidney disease (CKD). Although clustering of traditional risk factors with CKD is well recognized, kidney-specific mechanisms are believed to drive the disproportionate burden of CV disease. One perturbation that is frequently observed at high rates in patients with CKD is vascular calcification, which may be a central mediator for an array of CV sequelae. This review summarizes the pathophysiological bases of intimal and medial vascular calcification in CKD, current strategies for diagnosis and management, and posits vascular calcification as a risk marker and therapeutic target.

The prognosis of kidney transplant recipients with aorto-iliac calcification: a systematic review and meta-analysis

The prognosis of kidney transplant recipients (KTR) with vascular calcification (VC) in the aorto-iliac arteries is unclear. We performed a systematic review and meta-analysis to investigate their survival outcomes. Studies from January 1st, 2000 until March 5th, 2019 were included. Outcomes for meta-analysis were patient survival, (death-censored) graft survival and delayed graft function (DGF). Twenty-one studies were identified, eight provided data for meta-analysis. KTR with VC had a significantly increased mortality risk [1-year: risk ratio (RR) 2.19 (1.39-3.44), 5-year: RR 2.28 (1.86-2.79)]. The risk of 1-year graft loss was three times higher in recipients with VC [RR 3.15 (1.30-7.64)]. The risk of graft loss censored for death [1-year: RR 2.26 (0.58-2.73), 3-year: RR 2.19 (0.49-9.82)] and the risk of DGF (RR 1.24, 95% CI 0.98-1.58) were not statistically different. The quality of the evidence was rated as very low. To conclude, the presence of VC was associated with an increased mortality risk and risk of graft loss. In this small sample size, no statistical significant association between VC and DGF or risk of death-censored graft loss could be demonstrated. For interpretation of the outcomes, the quality and sample size of the evidence should be taken into consideration.

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.

Prognostic Value of Aortoiliac Calcification Score in Kidney Transplantation Recipients

BACKGROUND

Kidney recipients are increasingly older with arterial disease and extended arterial calcifications. In a kidney transplantation population, the prognosis value of aortic and iliac calcifications remains poorly explored. We aimed to assess the impact of pretransplantation aortoiliac vascular calcifications on patients, grafts survival, and cardiovascular events.

METHODS

This retrospective study included kidney transplantation patients from 2006 to 2012 for whom we had available presurgery abdominal computed tomography results (n = 100). We designed a score to quantify aortoiliac calcifications. Primary end points were patient and graft survival. Secondary end points were renal function and cardiovascular morbidity. Predictive performances of calcification score were assessed using area under receiver-operating characteristic curves. Patients were classified in quartiles depending on global calcium score value.

RESULTS

The cumulated rate of death and graft loss was 13% with no significant differences for survival between quartiles. No significant difference was observed in renal function (P = 0.4). Seventeen cardiovascular events were registered with a significant correlation between calcium score elevation and need of cardiovascular surgery during the follow-up (P = 0.01). Global calcium score had a predictive value of 74.5% (95% confidence interval 0.62-0.87) with 71% sensitivity and 73% specificity.

CONCLUSIONS

Aortoiliac calcifications do not decrease patient and graft survival. High calcium score predict cardiovascular events and procedures during the follow-up.

Thoracic aorta to femoral artery bypass allows secondary kidney transplantation in case of major iliac artery disease

Iliac artery major calcifications can compromise kidney graft. First-performed prosthetic arterial bypass from the thoracic aorta to the femoral artery allows secondary kidney transplantation. Four patients were submitted to this procedure. No patient died during the postoperative period or the follow-up. The median time to receive a kidney graft after the arterial surgery was 24 months (4-52). The normalization of the sera creatinine level was 6.4 days (2-15). The median follow-up was 38 months (7-79). In our experience, using lateral side clamping of the descendant thoracic aorta during the proximal implantation of the arterial graft avoids bleeding and visceral abdominal ischemia. The secondary performed kidney graft is safe on a very available arterial conduit.

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.

What is the relevance of systematic aorto-femoral Doppler ultrasound in the preoperative assessment of patients awaiting first kidney transplantation: a monocentric prospective study

BACKGROUND

The purpose of our study was to study the relevance of a systematic aorto-femoral colour Doppler ultrasound (DUS) in the evaluation of first renal transplant receivers.

METHODS

We prospectively studied 100 consecutive first renal transplant (RT) receivers. All patients had a preoperative physical examination with a careful vascular system evaluation including assessment of risk factors and colour DUS of aortic, iliac and femoral arteries. Renal transplantation was planned in the right iliac fossa with end-to-lateral vascular anastomoses. Clinical parameters, DUS results, operative and post-operative parameters at 3 months were compared according to the vascular assessment.

RESULTS

Among the 84 patients presenting with a normal preoperative physical arterial examination, 12 patients (14.3%) had an abnormal DUS, revealing atherosclerotic arteries, but no case of arterial stenosis. Among the 16 patients with abnormal physical arterial examination, 10 patients (62.5%) had abnormal DUS, including 4 cases of iliac stenosis. In 3 of the 16 patients (18.8%), DUS revealed right iliac artery stenosis requiring a modification in the surgical procedure. No additional vascular procedure was reported in the case of normal preoperative vascular examination. No technical problems during arterial anastomosis and no post-transplantation arterial complications were reported. In multivariate analysis, abnormal physical examination was the most significant risk factor of atherosclerotic infiltration in DUS.

CONCLUSION

The abnormality of arterial physical examination is the best clinical predictor of abnormal DUS in preoperative assessment of renal transplant receivers. However, the low sensitivity and positive predictive value of the physical examination do not support the conclusion that DUS can be avoided in patients with normal arterial physical examination. Nevertheless, in the case of arterial physical abnormality, 'for case' DUS is critical and helps in the surgical strategy in approximately 20% of cases.

Impairment of long-term graft function after kidney transplantation by intraoperative vascular complications

OBJECTIVE

Surgical complications in kidney transplantation often demand reoperation and therefore may severely affect graft survival. Major complications can be divided into ureteral and vascular related. Reoperation for ureteral complications is supposed to worsen graft survival, but vascular complications or anastomosis technique has not been evaluated for this issue.

PATIENTS AND METHODS

Between 1994 and 2004 260 patients underwent kidney transplantation. All ureterovesical junctions were performed in extravesical technique with ureteral stenting in 132/260 (50.7%) patients. Arterial end-to-side anastomosis was performed routinely except for 13/260 (5%) with end-to-end anastomosis. Mean follow-up was 43 months (0-121) including serum creatinine and ultrasound inter alia.

RESULTS

Graft failure rate was 8.1% 12 months and 12.7% 60 months postoperatively. Of the patients, 29/260 (11.5%) underwent reoperation within 30 days after transplantation (stenosis or leakage of the ureterovesical junction: n = 8; vascular complications: n = 10; thrombectomy for graft vein thrombosis: n = 1; evacuation of hematoma: n = 6; nephrectomy for complete graft ischemia: n = 4). Reoperation for vascular-related complications significantly enhances the risk of graft failure (P < 0.05, Cox proportional hazard) compared to urological complications. Arterial end-to-end anastomosis was also found to have a negative impact on graft survival. No correlation between routine ureteral stenting and ureteral stenosis or leakage was found.

CONCLUSION

Our data emphasize the importance of vascular complications compared to ureteral ones in kidney transplantation. Resolving 'non-urological' problems successfully, kidney transplantation is a safe procedure in urological hands.

Pertinent issues in pretransplant recipient workup

Renal transplantation is recognized as the treatment of choice in most patients with end-stage renal disease. The evaluation of the candidate for kidney transplantation has been the recent subject of clinical practice guidelines published by the European Renal Association- European Dialysis Transplant Association and the American Society of Transplantation. The purpose of this article is to review the current literature for urological evaluation and treatment of patients prior to renal transplantation. In India, urologists are involved in evaluating not only the genitourinary problems but also vascular access and, vascular anatomy and pathology especially related to major pelvic vessels. Hence, evaluation of the transplant recipient should include assessment of vascular access for hemodialysis, access for peritoneal dialysis, assessment of pelvic vessels to which renal allograft vessels need to be anastomosed and genitourinary system. In addition, review of the serological tests for infective viral diseases like hepatitis and human immunodeficiency viruses should always be done before starting clinical evaluation. A note of the evaluation performed by other specialists like nephrologist, cardiologist, endocrinologist, pulmonologist, anesthetist etc. should always be reviewed.

Results of Kidney Transplantation With Simultaneous Implantation of Vascular Graft

BACKGROUND

Arteriosclerosis and calcification of iliac arteries are common in patients on dialysis. This study sought to evaluate the outcome after kidney transplantation and simultaneous implantation of vascular grafts.

PATIENTS AND METHODS

In a single center study we evaluated donor and recipient data among 443 kidney transplantations in adults performed between January 2002 and October 2006. In 11 recipients (2.5%) a vascular graft (Gore-Tex) was implanted due to severe arterioscleroses of the iliac vessels.

RESULTS

Reconstruction of the lower limb blood supply was performed with an ileofemoral Gore-Tex-Bypass in 9 of 11 patients, with an aortofemoral bypass in 1 patient, and with a femoroiliac crossover bypass in 1 patient. Overall, 8 of 11 patients (73%) had an uneventful postoperative course. Six of 11 patients had primary graft function.

CONCLUSIONS

This analysis demonstrated that vascular reconstruction during kidney transplantation has to be performed rarely but has a strong impact on further life and kidney function. In 8 of 11 patients, kidney function at 6 months was good. Severe arteriosclerosis is usually not a contraindication for kidney transplantation. However, training in vascular surgery seems to be important to achieve satisfying results. In this series, simultaneous implantation of vascular prosthetic grafts was safe since there were no infectious complications of the graft itself.