Results of Open Pararenal Abdominal Aortic Aneurysm Repair: Tabular Review of the Literature

Midterm outcomes of physician-modified endovascular stent grafts for the treatment of complex abdominal aortic aneurysms in Korea: a retrospective study

Purpose

Physician-modified endovascular stent grafts (PMEG) are a good treatment option for complex abdominal aortic aneurysms (AAAs), especially in high-risk patients not amenable to open repair, and when commercial fenestrated devices are not available. We report our single-center experience with PMEG for the treatment of complex AAAs.

Methods

We retrospectively reviewed patients who underwent PMEG repair for AAA from November 2016 to September 2020 at our institution. Demographic data, anatomic characteristics, perioperative and postoperative outcomes, major adverse events, and 30-day mortality were analyzed.

Results

We identified 12 patients who underwent PMEG for complex AAA. The mean age was 74 years and the mean maximal AAA diameter was 58.1 mm. Indications for treatment included 4 impending or contained ruptures, 2 mycotic aneurysms, and 6 symptomatic cases. The technical success rate was 91.7%. Aneurysm sac regression was observed in 7 patients (58.3%), including 2 cases of complete regression. There was 1 aneurysm-related mortality at 3 months due to mycotic aneurysm. Also, there was 1 postoperative complication case of transient renal failure requiring temporary dialysis. At 1 year, there was 1 branch occlusion from the initial failed cannulation case and 2 type 1A endoleaks, and there was 1 case of open explantation.

Conclusion

PMEG showed a low technical failure rate and acceptable midterm stent durability and sac stability, comparable to conventional endovascular aneurysm repair. Despite the small number of cases, there was a tendency for a high sac regression rate, although longer follow-up is needed.

Five-factors Modified Frailty Index role as predictors of outcomes after proximal abdominal aortic aneurysms

BACKGROUND

The aim of the study was to evaluate the correlation between frailty, measured by the Five-Factor Modified Frailty Index (mFI-5) and mortality and all major adverse events (MAE) in patients who underwent proximal abdominal aortic aneurysm (p-AAA) open surgery (OS).

METHODS

Data of all elective patients submitted to p-AAA OS from 2010 to 2021 were recorded. Primary endpoints were 30-day mortality and mid-term survival and secondary endpoints included postoperative acute kidney injury (AKI), freedom from aortic reintervention and any MAE. The impact of frailty was assessed by univariate and multivariate analysis; mid-term overall survival were estimated using Kaplan-Meier method (log-rank test).

RESULTS

Two-hundred twenty-one patients (197 male, 24 female; aged 72.2±7.4) were included. Thirty-seven (16.4%) were octogenarians (>80 years). The mFI-5 was assessed in the entire group: mean mFI-5 was 0.29±0.12. One-hundred patients (100/221, 45.25%, 91:9 male-to-female ratio) were defined "frail" considering the mFI-5 cut-off >0.25. At univariate analysis a correlation was found between mFI-5>0.25 and mid-term mortality (Pearson correlation [r] 0.280, P<0.001) and AKI (r=0.146, P=0.030). No correlation with 30-day mortality was found (P not significant). At multivariate analysis mFI-5>0.25 increased the risk for midterm mortality (odds ratio 3.32, P=0.021) and postoperative AKI (OR 2.09, P<0.001). The effect of mFI-5>0.25 on mid-term mortality persisted after adjustment for age (P<0.001). Survival was estimated with Kaplan-Meyer method (mean follow-up of 52.7 months, 95% CI: 48.6-56.8); 68 (30.7%) deaths were recorded: 23 among non-frail patients (19.0%) and 45 among frail patients (45/100, 45%, P<0.001).

CONCLUSIONS

These findings suggest that mFI-5 is a tool capable to identify "frail" patients, who appear to be at increased risk of postoperative AKI and mid-term mortality, but not 30-day mortality. Five-factor modified Frailty Index assessment is simple, fast and can be widely applied in surgical practice to perform appropriate risk stratifications.

Tightrope Technique for facilitating complex endovascular aortic repair in patients with severely angulated neck

An 84-year-old presented with a large, symptomatic juxtarenal abdominal aortic aneurysm. Owing to severe angulation of the infrarenal neck, advancement of the distal bifurcated component caused dramatic lateral movement of the proximal physician-modified endovascular graft (PMEG) fenestrated device. This procedure risked aneurysm sac perforation and possible PMEG device displacement. To avoid this complication, the distal aspect of the PMEG device was tethered in place using endoscopic forceps to provide countertraction, similar to pulling a tightrope. This technique allowed for the uneventful placement of the distal bifurcated component without complication. This technique can overcome device placement challenges within an angulated aorta caused by large aneurysms.

Long-Term Results of Complex Abdominal Aortic Aneurysm Open Repair

This study investigated the long-term outcomes of patients treated with open surgical repair for complex abdominal aortic aneurysms (c-AAAs). A total of 119 patients with c-AAAs undergoing repair between January 2010 and June 2016 in a high-volume aortic center were included. The long-term imaging follow-up consisted of yearly abdominal ultrasound examinations and 5-year computed tomography angiography. At a median follow-up of 76 months (IQR 38 months), forty-three deaths (37%) and three (2.5%) aortic-related deaths were observed. Long-term chronic renal decline was observed in fifty (43.8%) patients, significantly correlated with post-operative acute kidney injury. During the follow-up, five reinterventions (4.3%) were performed. The present study suggests that open c-AAA repair can be performed with acceptable operative risk with durable results. To achieve the best possible long-term outcome, the open surgery repair of complex AAA should be performed in high-volume aortic centers and tailored to the patient.

Endovascular interventions in main renal artery pathologies: an overview and update

Renal arteries are involved in a wide spectrum of pathologies including atherosclerosis, fibromuscular dysplasia, Takayasu arteritis, aneurysms, and aortic type B dissections extending into main renal arteries. They manifest as renovascular hypertension, renal ischemia, and cardiovascular dysfunction. The location of the renal arteries in relation to the abdominal aortic aneurysm is a critical determinant of interventional options and long-term prognosis. This article provides a comprehensive review of the role of interventional radiologists in transcatheter interventions in various pathologies involving the main renal arteries with analysis of epidemiology, pathophysiology, newer interventional techniques, and management options.

[Acute Complex Endovascular Aortic Repair - Off-the-shelf vs. Surgeon-modified Stent Grafts]

INTRODUCTION

Treatment of complex abdominal and thoracoabdominal aortic aneurysms is challenging. Open surgical repair is a high-risk operation, especially in emergency cases. Endovascular aneurysm repair with a patient-specific custom-made stent graft in patients with symptomatic or ruptured complex aortic aneurysms is not possible, due to the manufacturing time required. In such cases, alternative endovascular techniques can be used.

RESULTS

The "off-the-shelf" and "surgeon-modified" stent grafts are valid options for the endovascular treatment of complex aneurysms in urgent and emergent patients. The former are standardised commercially manufactured fenestrated or branched stent grafts, which are available off-the-shelf with an anatomical feasibility in 50 - 80% of the patients. The "surgeon-modified" stent grafts refer to a technique, in which a commercially available stent graft is modified by the surgeon under sterile conditions directly before the implantation, in order to add the required fenestrations, scallops and/or branches. The modification takes approximately 60 - 120 min and haemodynamic stability of the patient is mandatory. Because of the off-label use of the commercial stent graft, detailed patient consent about the modification complications and risks should be performed whenever possible. A comparison of results on mortality and morbidity between "off-the-shelf" and "surgeon-modified" stent grafts has been published, although a direct comparison would be unfair for several reasons (different design, lack of extensive outcomes reports, long learning curve and different modification techniques).

CONCLUSION

The "surgeon-modified" and "off-the-shelf" fenestrated/branched stent grafts are used in the treatment of high-risk patients with symptomatic or contained ruptured complex aneurysms. The outcomes of the two techniques are good, although the long-term durability of the former should be further investigated.

Fenestrated repair improves perioperative outcomes but lacks a hospital volume association for complex abdominal aortic aneurysms

BACKGROUND

Complex abdominal aortic aneurysms (AAAs) have traditionally been treated with an open surgical repair (OSR). During the past decade, fenestrated endovascular aneurysm repair (FEVAR) has emerged as a viable option. Hospital procedural volume to outcome relationship for OSR of complex AAAs has been well established, but the impact of procedural volume on FEVAR outcomes remains undefined. This study investigated the outcomes of OSR and FEVAR for the treatment of complex AAAs and examined the hospital volume-outcome relationship for these procedures.

METHODS

A retrospective review of a statewide vascular surgery registry was queried for all patients between 2012 and 2018 who underwent elective repair of a juxtarenal/pararenal AAA with FEVAR or OSR. The primary outcomes were 30-day mortality, myocardial infarction, and new dialysis. Secondary end points included postoperative pneumonia, renal dysfunction (creatine concentration increase of >2 mg/dL from preoperative baseline), major bleeding, early procedural complications, length of stay, and need for reintervention. To evaluate procedural volume-outcomes relationship, hospitals were stratified into low- and high-volume aortic centers based on a FEVAR annual procedural volume. To account for baseline differences, we calculated propensity scores and employed inverse probability of treatment weighting in comparing outcomes between treatment groups.

RESULTS

A total of 589 patients underwent FEVAR (n = 186) or OSR (n = 403) for a complex AAA. After adjustment, OSR was associated with higher rates of 30-day mortality (10.7% vs 2.9%; P < .001) and need for dialysis (11.3% vs 1.8; P < .001). Postoperative pneumonia (6.8% vs 0.3%; P < .001) and need for transfusion (39.4% vs 10.4%; P < .001) were also significantly higher in the OSR cohort. The median length of stay for OSR and FEVAR was 9 days and 3 days, respectively. For those who underwent FEVAR, endoleaks were present in 12.1% of patients at 30 days and 6.1% of patients at 1 year, with the majority being type II. With a median follow-up period of 331 days (229-378 days), 1% of FEVAR patients required a secondary procedure, and there were no FEVAR conversions to an open aortic repair. Hospitals were divided into low- and high-volume aortic centers based on their annual FEVAR volume of complex AAAs. After adjustment, hospital FEVAR procedural volume was not associated with 30-day mortality or myocardial infarction.

CONCLUSIONS

FEVAR was associated with lower perioperative morbidity and mortality compared with OSR for the management of complex AAAs. Procedural FEVAR volume outcome analysis suggests limited differences in 30-day morbidity, although long-term durability warrants further research.

Protective Effects of Cold Ringer's Solution Perfusion in Abdominal Aortic Surgery Requiring Renal Artery Clamp

BACKGROUND/AIM

Treating abdominal aortic aneurysms (AAA) of the juxtarenal artery with renal artery clamps burdens the kidneys. We investigated the outcomes of intra-operative renal artery perfusion using the cold Ringer's solution method for renal protection.

PATIENTS AND METHODS

We enrolled 290 AAA patients who underwent open aortic repair. Surgical outcomes were investigated based on renal protection.

RESULTS

We evaluated 231 patients requiring infrarenal artery clamp (Group I), and 59 patients requiring perfusion in addition to the clamp (Group J). Patient demographics, acute kidney injury (AKI) incidence (Group I: 11.7% and Group J: 20.3%), hospital mortality (Group I: 1.3% and Group J: 1.7%), and 30-day mortality (Group I: 0.4% and Group J: 0%) were not different between the groups. The AKI incidence was low (13%) in cases requiring a renal artery clamp for ≥45 min (n=40).

CONCLUSION

Perfusion with cold Ringer's solution offers renal protection and may improve surgical outcomes.

Cross-clamp location affects short-term survival in patients undergoing open abdominal aortic aneurysm repair

INTRODUCTION

Open abdominal aortic aneurysm (oAAA) repair in the era of advanced endovascular aortic techniques is used in challenging anatomy. The impact of the location of the proximal aortic cross-clamp (suprarenal [SR] vs infrarenal [IR]) on outcomes remains to be determined. The aim of this study was to analyze the effect of proximal aortic cross-clamp location on short-term and overall survival after oAAA repair in a contemporary series.

METHODS

A retrospective cohort study was performed comparing the outcomes of patients undergoing oAAA repair with SR and IR aortic cross-clamping using the Vascular Quality Initiative registry from January 2003 to September 2018. Our primary end point was short-term mortality.

RESULTS

There were 7601 patients who underwent oAAA repair. Their mean age was 69.3 ± 8.5 years and 5555 patients (73.1%) were male. The aortic cross-clamp location was IR in 4044 patients (53.2%). The SR group had increased maximum AAA diameter (58 mm vs 56 mm; P < .0001), hypertension (85.5% vs 82.0%; P < .0001), preoperative creatinine (1.11 vs 1.08; P = .001), and were more likely to be in American Society of Anesthesiologists class IV (37.4% vs 30.6%; P < .0001). Postoperative renal failure occurred significantly more often in the SR group (24.4 vs 11.4%; P < .0001). Short-term mortality was 2.7% in the IR group and 4.7% in the SR group (P < .0001). Kaplan-Meier survival estimates were 93.7% and 83.8% in the IR group and 90.9% and 81.2% in the SR group at 1 and 5 years, respectively (P = .007). Multivariable analysis demonstrated that SR cross-clamping was significantly associated with short-term mortality (hazard ratio, 1.38; 95% confidence interval, 1.07-1.78; P = .01); however, it did not affect overall survival (hazard ratio, 1.13; 95% confidence interval, 1.00-1.28; P = .06).

CONCLUSIONS

A SR cross-clamp location is associated with an increased short-term mortality in patients undergoing oAAA repair. Overall survival is not affected by a SR cross-clamp location.

Juxtarenal Abdominal Aortic Aneurysm: Results of Open Surgery in an Academic Center

BACKGROUND

The objective of the study is to report our experience with conventional surgery for juxtarenal abdominal aortic aneurysms (JRAs) by evaluating incidence of acute renal failure and perioperative mortality. Secondary objectives are to evaluate general morbidity and the need for permanent postoperative dialysis and to assess the influence on long-term survival of preoperative risk factors and deterioration of perioperative renal function.

METHODS

A retrospective cohort study of 110 patients with JRA electively treated by open surgery between March 1992 and March 2018 was made. Data were obtained from clinical records, describing demographics, perioperative variables, and results. Acute kidney injury (AKI) was defined as 50% decrease in glomerular filtration rate or two-fold increase in serum creatinine. Multivariate analysis was performed by logistic regression to establish risk factors for renal failure. The influence of preoperative risk factors and deterioration of perioperative renal function on long-term survival was studied using Cox regression model. Descriptive and inferential statistics were used in the analysis.

RESULTS

110 consecutive patients were treated with an average age of 71 years, 82.7% male; 81% hypertensive and 41% active smokers. 46.3% had stage III or higher preoperative chronic kidney disease. Median diameter of the aneurysm was 5.7 cm. Interruption of bilateral renal flow was required in 73 patients (66.4%) and unilateral in 37 (33.6%). The average renal clamping time was 34.5 min. AKI occurred in 9 patients (8.2%). Two patients (1.8%) required postoperative dialysis, one of them permanent. Median hospital stay was 7 days. Thirty-three patients (30%) had at least one complication. Postoperative mortality was 2.7% (3 patients), two of them developed AKI. Multivariate analysis established a longer operative time and need for renal revascularization as independent risk factors for AKI. In the survival analysis, age, cerebrovascular disease, chronic obstructive pulmonary disease, and perioperative AKI were identified as risk factors for long-term mortality.

CONCLUSIONS

JRA open surgical repair can be performed with low morbidity and mortality. Although transient acute renal dysfunction may be relatively frequent, the need for hemodialysis is low. Our study is a reference point to compare with endovascular repair.

Results from a prospective multicenter feasibility study of Zenith p-Branch stent graft

OBJECTIVE

To evaluate the Cook Zenith p-Branch stent graft (William A. Cook Australia, Brisbane, Queensland, Australia) for the treatment of patients with asymptomatic juxtarenal or pararenal abdominal aortic aneurysms in a prospective, nonrandomized, multicenter, feasibility study conducted in the United States.

METHODS

The off-the-shelf p-Branch endograft incorporates a celiac scallop, superior mesenteric artery (SMA) fenestration, and two conical-shaped pivot renal fenestrations. Patients were eligible if the aneurysm did not extend above the distal margin of the SMA and the anatomy of renal and visceral arteries were compatible with one of the two p-Branch configurations (configuration A, renal fenestrations at the same longitudinal position; configuration B, offset renal fenestration).

RESULTS

A total of 30 patients (93% men; mean age, 73 years; mean aneurysm diameter, 64.7 ± 11.4 mm) were enrolled from January 2013 to June 2015. The mean follow-up period was 28.7 ± 12.5 months (as of October 2017). The technical success rate was 93% (28/30), with technical failure occurring in the first two study cases (device deliberately repositioned below the renal arteries because of difficulty in cannulating the renal arteries in one and an inability to place a renal stent in the other; both patients survived the procedure and withdrew from the study before the 12-month follow-up visit). No additional technical failures occurred after these first two cases, when an updated physician training and proctoring program was implemented. No 30-day mortality occurred. Of the remaining 28 patients, three died during the follow-up period; none within 30 days and none related to the device or procedure as determined by Clinical Events Committee adjudication. No treated aneurysm ruptures, conversion, or core laboratory-reported migration, or stent fracture were reported. The primary renal artery patency (interval to occlusion or reintervention for stenosis) rate was 88.6% ± 4.4% at 1 and 2 years. Two patients (7%) developed renal insufficiency secondary to a right renal artery stenosis in one patient and progression of chronic renal insufficiency in one patient. No patient required dialysis or developed mesenteric ischemia. Of the 28 patients, nine (32%) had undergone 13 secondary interventions for renal artery occlusion (n = 2), SMA occlusion (n = 1), renal or SMA stenosis (5 interventions in 4 patients), renal stent kinking (n = 1), lower extremity claudication (n = 2 in the same patient), type III endoleak between the p-Branch and renal stent (n = 1), and type II endoleak (n = 1).

CONCLUSIONS

These early and intermediate results, which incorporated physician learning curves, support the safety and feasibility of the off-the-shelf Zenith p-Branch device. Follow-up examinations through 5 years will continue to assess the long-term results.

Recent Development and Long-Term Results of Open vs EVAR for Pararenal Abdominal Aortic Aneurysms

In this article, I would like to discuss on the two different treatment options (Open vs EVAR) for pararenal abdominal aortic aneurysm (the term "PRAAA" is not clearly defined and classified). Recently, complex endovascular treatment [Fenestrated EVAR (F-EVAR), Chimney (Snorkel) EVAR (C-EVAR, S-EVAR), Branched EVAR (B-EVAR)] have been developed and applied in selected patients, with encouraging early results; however, the high rate for secondary reinterventions and long-term results remain uncertain. This article introduce new devices and a new concept with endovascular aneurysm sealing (EVAS) are currently available on the market for the treatment of PRAAA. Open repair of PRAAA can be performed with low mortality and long-term survival is favorable from single-center experience in the real world and others. We conclude that open repair remains the golden standard treatment in most centers for PRAAA. However, EVAR of PRAAA may represent an alternative option in high-risk patients. Because the indications and circumstances for PRAAA vary based on patient-specific comorbidities and anatomy, it is recommended that vascular surgeons should be familiar with both treatment strategies and tailor-made strategy for improved long-term results for PRAAA. (This is a translation of Jpn J Vasc Surg 2018; 27: 303-308.).

Treatment of Abdominal Aortic Pathology

Abdominal aortic pathology is a diverse topic, ranging through a broad span of possible pathologies. The treatment options are equally vast, particularly with the ever-expanding endovascular techniques. In this article, we discuss management strategies for abdominal aortic aneurysms and aortic occlusive disease, because they represent some of the most common pathologies encountered in clinical scenarios.

Ruptured Juxtarenal Abdominal Aortic Aneurysm Treated With a Fenestrated EVAR Graft Intended for a Different Patient

Treatment of juxtarenal abdominal aortic aneurysms (AAAs) remains challenging. A 79-year-old male who had infrarenal endovascular repair of abdominal aortic aneurysm (EVAR) 13 years previously presented with leaking juxtarenal AAA. Emergency fenestrated EVAR (FEVAR) was performed utilizing a stent graft designed and built for a different patient. Despite the need to embolize the celiac artery prior to covering it with the stent graft in order to achieve adequate proximal seal, the patient had uneventful recovery.

Survival after repair of pararenal and paravisceral abdominal aortic aneurysms

OBJECTIVE

The objective of this study was to review our 27-year clinical experience with open proximal abdominal aortic aneurysm repairs, with a focus on long-term survival.

METHODS

A retrospective cohort study was undertaken of all patients who underwent proximal abdominal aortic aneurysm repair between 1986 and 2013 at a tertiary care referral center. Demographics, operative variables, complications, and 30-day mortality were analyzed. Postoperative acute kidney injury was analyzed by the RIFLE (Risk, Injury, Failure, Loss, End-stage renal disease)/Acute Kidney Injury Network criteria. Long-term survival was assessed through review of electronic medical records and the Social Security Death Index. Associations between demographics and complications were investigated to determine predictors of long-term survival.

RESULTS

The study identified 245 patients. Mean age was 71 years (range, 38-92 years); 69% were men, and 88% were white. Aneurysm type was juxtarenal in 127 patients (52%), suprarenal in 68 patients (28%), and type IV thoracoabdominal in 50 patients (20%). In-hospital mortality was 3.3% (eight patients), and 30-day mortality was 2.9% (seven patients). At least one major complication occurred in 64% of the patients, which included the following: acute kidney injury, 60% (persistent acute kidney injury at discharge, however, was 28%, and hemodialysis at discharge was 1.6%); major pulmonary complications, 22%; myocardial infarction, 4%; visceral ischemia, 2%; and paraplegia, 0.5%. Median follow-up was 54 months. Kaplan-Meier survival estimates were 70% at 5 years and 43% at 10 years. Variables associated with poorer survival included congestive heart failure (hazard ratio [HR], 3.5; P < .001), chronic obstructive pulmonary disease (HR, 1.8; P < .002), and increased aneurysm size at presentation (HR, 1.1; P < .013). Persistent stage 3 acute kidney injury was associated with poor long-term survival.

CONCLUSIONS

Open surgical repair of proximal abdominal aortic aneurysms can be performed with low mortality. Acute kidney injury is the most frequent complication, but the need for hemodialysis at discharge is low. Long-term survival is favorable. These data should assist in establishing benchmarks for endovascular repair of complex proximal abdominal aortic aneurysms.

Specialized vascular floors after open aortic surgery: cost containment while preserving quality outcomes

BACKGROUND

Postoperative care of open abdominal aortic surgery (OAAS) traditionally involves the intensive care unit (ICU). We hypothesized that in patients without an indication for postoperative ICU admission, admission to a specialized vascular floor unit (hemodynamic monitoring, 2:1 nursing) offers cost savings to both payer and institution without compromising care.

METHODS

The electronic medical record was used to collect perioperative data for patients who underwent OAAS between July 2007 and July 2011. The university's cost accounting system provided information on revenue, total margin, and professional billing. Patients with ICU indications (spinal drain, Swan-Ganz monitoring, vasopressors, intubation, or blood product resuscitation) were excluded. Comparative cost and outcome analysis was performed on vascular ward and ICU admissions using the Fisher's exact test for dichotomous categorical variables and the Student's t-test for continuous variables. Long-term survival comparison was calculated using Kaplan-Meier survival estimates.

RESULTS

One hundred thirty of 215 patients were included for analysis (85 excluded, 51 floor, 79 ICU). Perioperative data amongst the floor and ICU cohorts were similar. Day of operation professional billing fees were comparable (ICU $13,365 vs. floor $12,626; P = 0.18); however, postoperative professional fees were significantly higher in the ICU cohort (ICU $3,258 vs. floor $2,101; P = 0.001) primarily because of intensivist billing. The hospital generated an average of 8.7% more revenue from the ICU cohort (ICU $37,770 vs. floor $34,756; P = 0.023). This was offset by greater expenses in the ICU cohort (ICU $30,756 vs. floor $25,144; P = 0.02), yielding a hospital profit margin of 107.5% favoring floor admission (ICU $2,858 vs. floor $5,931; P = 0.19). Duration of stay was similar (ICU 8.0 days vs. floor 7.8 days; P = 0.86). Kaplan-Meier survival analysis was not significantly different between cohorts (ICU 10.1%, median follow-up, 1,070 days vs. floor 0%, median follow-up, 405 days; P = 0.13).

CONCLUSIONS

Postoperative admission to the ICU is not always necessary after OAAS. Specialized vascular floors offer a financial savings to both payer and institution, which allows for simultaneous cost containment while preserving quality outcomes.

Percutaneous revascularization for ischemic nephropathy: the past, present, and future

Occlusion of the renal arteries can threaten the viability of the kidney when severe, in addition to accelerating hypertension and circulatory congestion. Renal artery stenting procedures have evolved from a treatment mainly for renovascular hypertension to a maneuver capable of recovering threatened renal function in patients with “ischemic nephropathy” and improving management of congestive heart failure. Improved catheter design and techniques have reduced, but not eliminated hazards associated with renovascular stenting. Expanded use of endovascular stent grafts to treat abdominal aortic aneurysms has introduced a new indication for renal artery stenting to protect the renal circulation when grafts cross the origins of the renal arteries. Although controversial, prospective randomized trials to evaluate the added benefit of revascularization to current medical therapy for atherosclerotic renal artery stenosis until now have failed to identify major benefits regarding either renal function or blood pressure control. These studies have been limited by selection bias and have been harshly criticized. While studies of tissue oxygenation using blood oxygen level dependent (BOLD) MR establish that kidneys can adapt to reduced blood flow to some degree, more severe occlusive disease leads to cortical hypoxia associated with microvascular rarefication, inflammatory injury and fibrosis. Current research is directed toward identifying pathways of irreversible kidney injury due to vascular occlusion and to increase the potential for renal repair after restoring renal artery patency. The role of nephrologists likely will focus upon recognizing the limits of renal adaptation to vascular disease and identifying kidneys truly at risk for ischemic injury at a time point when renal revascularization can still be of benefit to recovering kidney function.