Permanent Decline of Renal Function after Infrarenal Abdominal Aortic Aneurysm Repair—Frequency and Risk Factors

Diseases of the Aorta and Kidney Disease: Conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) is an independent risk factor for the development of abdominal aortic aneurysm (AAA), as well as for cardiovascular and renal events and all-cause mortality following surgery for AAA or thoracic aortic dissection. In addition, the incidence of acute kidney injury (AKI) after any aortic surgery is particularly high, and this AKI per se is independently associated with future cardiovascular events and mortality. On the other hand, both development of AKI after surgery and the long-term evolution of kidney function differ significantly depending on the type of AAA intervention (open surgery vs. the various subtypes of endovascular repair). Current knowledge regarding AAA in the general population may not be always applicable to CKD patients, as they have a high prevalence of co-morbid conditions and an elevated risk for periprocedural complications. This summary of a Kidney Disease: Improving Global Outcomes Controversies Conference group discussion reviews the epidemiology, pathophysiology, diagnosis, and treatment of Diseases of the Aorta in CKD and identifies knowledge gaps, areas of controversy, and priorities for future research.

Central and peripheral arterial diseases in chronic kidney disease: conclusions from a Kidney Disease: Improving Global Outcomes (KDIGO) Controversies Conference

Chronic kidney disease (CKD) affects about 10% of all populations worldwide, with about 2 million people requiring dialysis. Although patients with CKD are at high risk of cardiovascular disease and events, they are often underrepresented or excluded in clinical trials, leading to important knowledge gaps about how to treat these patients. KDIGO (Kidney Disease: Improving Global Outcomes) convened the fourth clinical Controversies Conference on the heart, kidney and vasculature in Dublin, Ireland, in February 2020, entitled Central and Peripheral Arterial Diseases in Chronic Kidney Disease. A global panel of multidisciplinary experts from the fields of nephrology, cardiology, neurology, surgery, radiology, vascular biology, epidemiology, and health economics attended. The objective was to identify key issues related to the optimal detection, management, and treatment of cerebrovascular diseases, central aortic disease, renovascular disease, and peripheral artery disease in the setting of CKD. This report outlines the common pathophysiology of these vascular processes in the setting of CKD, describes best practices for their diagnosis and management, summarizes areas of uncertainty, addresses ongoing controversial issues, and proposes a research agenda to address key gaps in knowledge that, when addressed, could improve patient care and outcomes.

Clinical effect of accessory renal artery coverage after endovascular repair of aneurysms in abdominal and thoracoabdominal aorta

BACKGROUND

The aim of our systematic review and meta-analysis was to assess the effect of accessory renal artery (ARA) coverage on renal function in terms of acute kidney injury (AKI), renal infarction, chronic renal failure (CRF), and mortality in patients undergoing standard endovascular aortic aneurysm repair (EVAR) or endovascular repair of complex aneurysms.

METHODS

An electronic search of the English language medical literature from 2000 to September 2020 was conducted using the MEDLINE, EMBASE, and Cochrane databases with the PRISMA (preferred reporting items for systematic reviews and meta-analyses) method for studies reporting on ARA management in patients undergoing endovascular repair of aneurysms in the abdominal and thoracoabdominal aorta. The patients were divided into two groups: group 1, patients with ARA coverage; and group 2, patients without an ARA or without coverage of the ARA. Each group included two arms, one of patients who had undergone standard EVAR and one of patients who had undergone endovascular treatment of a complex aortic aneurysm. The GRADE (grading of recommendations assessment, development, evaluation) approach was used to evaluate the quality of evidence and summary of the findings. The primary outcomes included the incidence of AKI, renal infarction, CRF, and mortality.

RESULTS

Ten retrospective, nonrandomized, control studies were included in the systematic review reporting on 1014 patients (302 with a covered ARA vs 712 without an ARA or without ARA coverage). In six studies, the mean diameter of the covered ARA was <4 mm (range, 2.7-3.4 mm). The mean follow-up was 22.74 months (range, 1-42 months). In the standard EVAR subgroup, the risk of AKI (odds ratio [OR], 0.72; 95% confidence interval [CI], 0.21-2.51; I² = 0%] in the early period, and CRF (OR, 4.44; 95% CI, 0.46-42.61; I² = 87%) and death (OR, 0.91; 95% CI, 0.36-2.31; I² = 0%) during follow-up were similar between groups 1 and 2. Only the risk of renal infarction was greater in group 1 than in group 2 (OR, 93.3; 95% CI, 1.48-5869; I² = 92%). In the complex aneurysm repair subgroup, the risk of AKI (OR, 1.85; 95% CI, 0.61-5.64; I² = 42%) in early period and CRF (OR, 1.64; 95% CI, 0.88-3.07; I² = not applicable) and death (OR, 3.63; 95% CI, 0.14-96.29; I² = 56%) during follow-up were similar between groups 1 and 2. Only the risk of renal infarction was greater for group 1 compared with group 2 (OR, 8.58; 95% CI, 4.59-16.04; I² = 0%).

CONCLUSIONS

ARA (<4 mm) coverage in patients undergoing standard EVAR or endovascular repair of complex aneurysms is associated with an increased risk of renal infarction. However, we found no clinical effects of ARA coverage on renal function or mortality in early postoperative and follow-up period. Preservation of an ARA >4 mm should be considered.

Effects of Left Renal Vein Ligation During Open Abdominal Aortic Aneurysm Repair on Renal Function

OBJECTIVE

Left renal vein (LRV) ligation is performed during open abdominal aortic aneurysm (AAA) repair to facilitate proximal anastomosis. Its impact on short, medium, and long term renal function has not been investigated in detail using appropriately validated endpoints.

METHODS

This was a nested case control study using data from a prospectively maintained AAA institutional dataset (tertiary centre). A total of 76 patients who underwent elective open AAA repair and had LRV ligation (1 January 2012 to 1 January 2018) were individually case matched based on age (within two years), sex, estimated glomerular filtration rate (eGFR), American Society of Anesthesiologist (ASA) score, chronic kidney disease (CKD) stage, and history of diabetes with 76 patients who had open AAA repair without LRV ligation. Renal outcomes were compared between groups, including proportion of patients developing acute kidney injury (AKI) using the Kidney Disease Improving Global Outcomes (KDIGO) criteria, proportion developing major adverse kidney events (MAKE90) at 90 days (comprising mortality and/or decrease in eGFR >25%), and absolute decrease in eGFR at latest follow up.

RESULTS

A higher proportion of patients developed AKI and MAKE90 in the LRV ligation group (AKI: 11 patients [14.8%] vs. 2 [2.6%], p = .009; MAKE90: 6 [7.9%] vs. 1 [1.3%] p = .053, in the LRV ligation and the non-LRV ligation groups, respectively) - even though the difference in the MAKE90 endpoint was not statistically significant. Changes in eGFR were not statistically different in the LRV ligation group at 90 days (4.0 ± 1.1 mL/min/1.73 m²vs. 4.4 ± 2.1, p = .64) or by the time of latest follow up (median: 28 months; 3.7 ± 1.6 vs. 2.6 ± 2.0, p = .55).

CONCLUSION

Ligation of the LRV is associated with increased levels of AKI and renal deterioration in the early post-operative phase using validated reporting criteria; however, long term renal function does not seem to be affected.

Patient Safety Indicators are an insufficient performance metric to track and grade outcomes of open aortic repair

OBJECTIVE

National rankings of hospitals rely on outcomes-based evaluation to assess the performance of surgical programs, particularly those performing high-risk elective surgical procedures such as open aortic repair. Various classification systems exist for tracking outcomes, but increasingly the International Classification of Diseases, Tenth Revision-based Agency for Healthcare Research and Quality Patient Safety Indicators (PSIs) are used as a publicly reported comparison measure of hospital quality performance. We sought to critically evaluate the accuracy of the existing vehicles to assess open aortic repair outcomes in an established program.

METHODS

This is a case-control study of patients who underwent open abdominal aortic aneurysm repair at the Johns Hopkins Medical Institutions from 2004 to 2018. Patients' characteristics and outcomes were collected as part of a prospectively maintained retrospective database. For each case, hemorrhagic, cardiac, respiratory, renal, wound, and thromboembolic complications were identified with the unique definitions used for open abdominal aortic aneurysm repair by the American College of Surgeons National Surgical Quality Improvement Program (NSQIP) database, the Society for Vascular Surgery Vascular Quality Initiative (VQI) database, and the Agency for Healthcare Research and Quality PSI initiative.

RESULTS

Of the 154 patients included in the study, 79 (51.0%) were identified as having a complication as defined by the VQI, 46 (29.7%) according to the NSQIP, and 15 (9.7%) according to the PSI system (P < .001). Patients most likely to incur a complication in the PSI system were those with a pararenal or more extensive aneurysm, with baseline congestive heart failure, requiring a supramesenteric clamp (all P < .01), or with an aneurysm >6.5 cm in diameter (P = .02). The NSQIP and VQI systems both identified more postoperative hemorrhagic, respiratory, renal, and wound complications than the PSI system did (P < .05). The VQI system identified the most renal complications (52; P < .001); factors unique to incurring a complication in the VQI include use of a suprarenal clamp and performance of an aortorenal bypass procedure as part of the repair (P < .01). Particularly weak correlation was noted between the PSI system and the VQI with respect to renal outcomes (ρ = 0.163).

CONCLUSIONS

The PSI system identified fewer important complications than either of the clinically focused databases, with the VQI capturing the most postoperative events, mostly because of its stringent definition of renal injury. We conclude that the PSI system should not form the basis of grading hospital performance in comparing clinically relevant complications of open aortic surgery programs.