Renal function after aortic stent-grafting including coverage of renal arterial ostia

The effect of Endovascular Aneurysm Repair on Renal Function in Patients Treated for Abdominal Aortic Aneurysm

Aim:

The effect of endovascular aneurysm repair in patients treated for abdominal aortic aneurysm has not been clearly defined. The objective of the present article was to provide a contemporary literature review and perform an analysis to determine the effect of EVAR on renal function in the early post-operative period and during follow-up.

Methods:

A systematic review of the literature was undertaken to identify all studies reporting the effect of EVAR on renal function. Outcome data were pooled and combined overall effect sizes were calculated using fixed or random-effects models.

Results:

Thirty-two studies reporting on 24846 patients were included. Acute renal failure after EVAR occurred with an estimated frequency of 9% (95%CI: 5-16%; I2=97%). Median follow-up period was 19.5 months (range 1-60 months). The estimated frequency of chronic renal failure during follow-up was 7% (95%CI: 3-17%; I2=98%). Hemodialysis was required in 2% (1-3%; I2=97%) of the cases.

Conclusion:

High-level evidence demonstrating the effect of EVAR on the incidence of acute and chronic renal failure is lacking. Based on the current available data, nearly 10% of patients undergoing EVAR for AAA have an increased risk for renal dysfunction after the procedure. Whether this deterioration may lead to a worse outcome has not been adequately proved.

Endovascular Rescue of a Maldeployed Aortic Stent-Graft Causing Renal Artery Occlusion: Technical Considerations

The technical success of an endovascular abdominal aortic aneurysm repair depends on the endograft exclusion of the aneurysm along with preservation of flow to major aortic branches, such as the renal or hypogastric artery. A proximally malpositioned aortic endograft may result in inadvertent renal artery occlusion, which may lead to renal infarction with irreversible loss of the renal function. In this report, the authors describe an endovascular rescue technique to salvage a proximally maldeployed aortic endograft that inadvertently covered the renal artery orifice. Physicians performing endovascular aneurysm procedures should be aware of such a salvage maneuver in the event an aortic endograft is proximally maldeployed and occludes the renal artery orifice.

Custom-made Stent-Grafts for Aortic Aneurysm Repair Using Gianturco Z Stents and Woven Polyester: Healing in an Animal Model

The purpose of this study was to evaluate the healing at 6 months of aortic stent-grafts custom-made by using Z stents and woven polyester in an animal model. Stent-grafts were built by a published method using autoexpandable stainless steel stents continuously compiled with polyester sutures and covered with a woven polyester membrane. Fourteen stent-grafts of 3 different designs were deployed under fluoroscopic control into the thoracic and the abdominal aorta of 7 adult sheep. At 6 months, all the implants of the sheep that survived the implantation were angiographed and harvested for macroscopy and microscopy. All stentgrafts were implanted successfully and remained patent from then to the explantation procedure. All stent-grafts implanted among the 6 of 7 (86%) animals that survived after the implantation remained patent, stayed free from local complications, and did not migrate during more than 6 months. In all these cases during this period, the implant functioned as a satisfactory aortic substitute while the aortic segment containing the graft kept a normal structure. There was no adverse effects of the presence of the implant upon the aorta or the animal. Stent-grafts home-made according to the described methods gave results at 6 months in this animal model compatible with a safe clinical application among humans.

Improvement in Proximal Aortic Endograft Fixation: An Experimental Study Using Different Stent-Grafts in Human Cadaveric Aortas

Purpose:

To compare the proximal fixation characteristics of different types of stent-grafts (SG) and the adjunctive effect of a proximally placed Palmaz stent.

Methods:

Human cadaveric aortas were obtained at autopsy and cut into 30 aortic segments. Appropriately oversized (10% to 20%) commercial stent-grafts (Zenith, Ancure, Excluder, Talent) and 4 configurations of homemade Palmaz-based stent-grafts (polytetrafluoroethylene or polyester coverings each with no uncovered proximal edge or a 20-mm bare section of stent) were implanted 20 mm into an aortic segment and balloon dilated. Each segment was placed in an experimental apparatus to measure the dislodgment force. Bare Palmaz stents were used to reinforce the proximal fixation of the commercial stent-grafts, and the measurements were repeated. Manual anastomoses were made and their dislodgment force tested for comparison.

Results:

The median dislodgment force ranged from 6.5 N for the Excluder to 26.5 N for the Zenith (8.0 N for the Talent, 11.8 N for the Ancure, and 8.1 to 10.7 N for the various Palmaz stent-graft designs). There was no significant difference between the Zenith and the Ancure groups or between the Excluder and the Talent groups. However, the Zenith and Ancure devices required significantly higher (p = 0.0004) force (∼25%) to displace them than the other stent-grafts tested. With the Palmaz stent added to the proximal attachment site, the median dislodgment force for the different commercial endografts was significantly improved for all devices (p < 0.03): 34% for the Zenith device, 69% for the Ancure, 73% for the Talent, and 80% for the Excluder endoprosthesis.

Conclusions:

The Zenith stent-graft had the best resistance to dislodgment. An additional Palmaz stent placed at the proximal attachment site greatly improves endograft fixation regardless of the type of stent-graft. For complex aneurysm necks or for intraoperative type I endoleak management, an adjunctive Palmaz stent could be used.

Placement of endovascular stent across the branching arteries: long-term serial evaluation of stent-tissue responses overlying the arterial orifices in an experimental study

PURPOSE

This study was designed to investigate the effects of stenting across the branching arteries on the patency and stent-tissue responses over the branching arterial orifices.

METHODS

Thirteen dogs were observed after placing aortic stents across the celiac arteries (CA), superior mesenteric arteries (SMA), and renal arteries (RA). The animals were grouped according to stent types: large-cell group (n = 6) and small-cell group (n = 7). Angiography was performed to evaluate the branching artery patency at 2, 6, and 12 months after stent insertion, and the stent-tissue responses covering the orifices were evaluated on histopathologic examination.

RESULTS

All branching arteries were patent on follow-up angiography; however, three patterns of stent-tissue responses over the orifices were observed: neointimal layering, bridging septa, and papillary hyperplasia. Although neointimal layering and bridging septa were evenly observed, severe papillary hyperplasia was more frequent at SMA and CA than RA. Four RA showed less than 50% ostial patency, and localized infarct was observed in six kidneys (24%). The ostial patency tended to decrease with small-cell stent during the follow-up period.

CONCLUSIONS

Various stent-tissue responses over the branching artery orifices are induced by the aortic stent covering the branching arteries and may not be easily detected by conventional angiography. Subclinical renal infarct also may occur despite patent renal angiography.

Suprarenal endograft fixation and medium-term renal function: systematic review and meta-analysis

BACKGROUND

Suprarenal fixation is widely used in endovascular aneurysm repair. Numerous small, underpowered studies have concluded that it does not increase the risk of renal impairment compared with infrarenal fixation. A recent meta-analysis demonstrated that renal infarction is more common with suprarenal fixation, but the effect on renal function remains unclear.

METHODS

Electronic abstract databases, article reference lists, and conference proceedings were searched for series reporting renal function data after suprarenal fixation. There was considerable study heterogeneity with respect to key factors such as pre-existing renal dysfunction and length of follow-up. Authors were contacted to obtain individual patient data for a pooled reanalysis using standardized criteria.

RESULTS

Of 46 potentially relevant citations, only 11 were eligible for inclusion in the meta-analysis. Complete data sets were available for four studies (1065 patients), with a median follow-up of 33 months. Kaplan-Meier curves were constructed for postoperative renal impairment in the suprarenal fixation and infrarenal fixation groups and compared by the log-rank test. Median time free of renal impairment was 38.5 months in the infrarenal fixation group compared with 32.4 months in the suprarenal fixation group (P = .0038). However, to account for significant methodologic differences, further analysis was required using a Weibull regression model fitted in open Bayesian inference using Gibbs sampling (BUGS). The pooled hazard ratio for deterioration of renal function after suprarenal fixation was 0.6 (95% confidence interval, 0.3-10).

CONCLUSION

Currently available data are insufficient to determine the precise effect of suprarenal fixation on medium-term renal function. Conventional Kaplan-Meier analysis of the pooled data set suggested that suprarenal fixation increased the risk of renal dysfunction; however, the effect disappeared when sophisticated statistical modelling was performed to account for study heterogeneity. A randomised controlled trial of suprarenal fixation may resolve this issue.

Visceral and Renal Artery Complications of Suprarenal Fixation during Endovascular Aneurysm Repair

BACKGROUND

The effect of suprarenal fixation of endovascular grafts on renal and visceral artery function remains undefined. This study aimed to determine renal and visceral artery complications following suprarenal fixation during endovascular aneurysm repair (EVR).

METHODS

Prospectively collected data from 112 patients who received suprarenal fixation (group SF) and 36 patients who received infrarenal fixation (group IF) in a single institution from December 1997 to April 2005 were reviewed retrospectively. Median follow-up was 26 months (range 0.1-101 months).

RESULTS

Stent struts extended to or above the level of 106 (94.6%) right renal arteries, 104 (92.9%) left renal arteries, 49 (43.8%) superior mesenteric arteries (SMA), and 7 (6.3%) celiac arteries in group SF. This group had 2 (1.8%) unintentional main renal artery occlusions, of which 1 was successfully treated at the first procedure with a renal stent. There was 1 (0.9%) SMA occlusion which resulted in bowel infarction and death. Group IF had no renal or visceral artery complications. There were no late-onset occlusions or infarcts. There was no significant difference in median serum creatinine between groups SF and IF at 1 month (p = 0.18) and 6 months to 12 months (p = 0.22) follow-up. The change in serum creatinine over time was also not significantly different within each group (SF, p = 0.09; IF, p = 0.38).

CONCLUSIONS

In this study, suprarenal fixation was associated with a very small incidence of immediate renal and visceral artery occlusion. There did not appear to be any medium-term sequelae of suprarenal fixation.

The Mid-term Effect of Bare Metal Suprarenal Fixation on Renal Function Following Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

The aim of this study was to assess the mid term effect of proximal bare metal fixation design on renal function in patients undergoing endovascular repair (EVR) of abdominal aortic aneurysm (AAA).

METHODS

Consecutive EVR patients for AAA from December 1995-2001 were included and grouped to either infrarenal (Group 1) or uncovered suprarenal (Group 2) fixation. Peri-operative renal function and at 6, 12 and 24 months was determined by serum creatinine (sCr mmol l(-1)) and Cockroft-Gault creatinine clearance (CrC ml min(-1)). Changes in renal function were compared using non-parametric analysis.

RESULTS

Of the 179 EVR procedures during this six-year period, paired renal data was available for 135 patients at a minimal follow-up of 6 months (Gp1, n = 63; Gp2, n = 72). Median pre-EVR sCr and CrC were 113, 57 in Group 1 and 108, 58 in Group 2, p = NS. There was no significant deterioration in renal function within or between either group at 2 years post-EVR: median sCr, CrC values were 118, 56 (Group 1) and 111, 56 (Group 2), all p = NS.

CONCLUSION

This study suggests mid-term renal function remains unaffected following EVR of AAA, irrespective of proximal fixation type. Designs to improve stent durability and EVR applicability do not appear to compromise renal function.

Renal interventions after abdominal aortic aneurysm repair using an aortic endograft with suprarenal fixation

BACKGROUND

Our aim was to determine whether suprarenal fixation in endografts compromises renal artery (RA) flow and whether subsequent RA intervention is precluded by the stent struts.

METHODS

Prospectively acquired data from 104 patients with endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm using the Zenith endograft (Cook, Inc., Bloomington, IN) were analyzed. The Zenith device uses a 26-mm, uncovered, barbed Z stent for suprarenal function.

RESULTS

No RA stenosis, occlusion, or infarction resulted from the suprarenal stent. In 3 of 104 (2.9%) patients, RA compromise (2 stenoses, 1 occlusion) was caused by impingement of graft material on the lowermost RA. The 2 RA stenoses were stented successfully at 1 and 7 months post-EVAR. Six of 104 (5.8%) patients developed late stenoses unrelated to the endograft: all were stented successfully from 19 to 36 months after EVAR. One patient with severe RA stenosis had balloon angioplasty pre-EVAR and then was stented electively 6 weeks post-EVAR.

CONCLUSIONS

Our data show that the suprarenal fixation of the Zenith aortic endograft does not cause RA stenosis, occlusion, or infarction, nor does it preclude post-EVAR renal artery intervention.

Renal Function in Patients with Abdominal Aortic Aneurysm

AIMS

Renal dysfunction occurs occasionally after the repair of abdominal aortic aneurysm (AAA), and preoperative renal function is considered as one of the potential causes. The present study was designed to evaluate and compare renal function and risk factors of AAA patients with those of hypertensive patients.

METHODS

We prospectively examined 95 patients with AAA and 72 patients with essential hypertension (HT) without other cardiovascular diseases (CVD). Renal function, urinary albumin excretion (UAE) and renal scintigraphy were compared. Kidney size was calculated using ultrasonography.

RESULTS

Serum creatinine and creatinine clearance in AAA patients was worse than in HT patients. Smoking status was more apparent in AAA patients. Renal artery stenosis occurred in 8 patients with AAA. Renal scintigraphy showed normal function in 19%, hypofunction in 69% and severe dysfunction in 12% of the AAA patients, and normal function in 42% and hypofunction in 58% of the HT patients (p < 0.0001). Multivariate linear regression analysis showed that renal function was related to age, UAE, CVD, smoking status and kidney size for all patients, UAE, CVD, smoking status and kidney size for AAA patients, and age and kidney size for HT patients.

CONCLUSION

Renal function of AAA patients was worse than HT patients without other CVD. The risk factors for renal dysfunction were different between AAA and HT patients. These preoperative conditions may relate to the postoperative renal dysfunction seen in AAA patients.

Transrenal Fixation of Aortic Stent-Grafts: Short- to Midterm Effects on Renal Function—A Systematic Review

PURPOSE

To perform a systematic review of the short- to midterm effects of transrenal fixation of aortic stent-grafts on renal function in patients with abdominal aortic aneurysms.

MATERIALS AND METHODS

A search of the PubMed, MEDLINE, and EMBASE databases for English-language literature was performed. Studies with at least 10 patients were included for data analysis. Only studies on transrenal fixation of aortic stent-grafts that included follow-up results for renal function were included. A log-linear model was used for meta-analysis to compare transrenal fixation with infrarenal fixation.

RESULTS

Twenty-two studies met the inclusion criteria. Because two studies analyzed the same group of patients, one was excluded, for a total of 21 studies. Comparisons between transrenal fixation and infrarenal fixation were found in seven studies. For transrenal versus infrarenal fixation, the combined odds ratio, 95% confidence interval, and P value were found to be statistically significant with respect to postprocedural renal infarction only (combined odds ratio, 5.189; 95% confidence interval: 3.198, 8.420; P < .001). No significant difference was found between transrenal and infrarenal fixation with respect to renal dysfunction, renal artery occlusion, or endoleaks (P > .05).

CONCLUSION

Transrenal fixation of aortic stent-grafts seems to be a relatively safe alternative compared with infrarenal fixation in terms of short- to midterm follow-up. Postprocedural renal infarction, however, was significantly higher for transrenal fixation.

Fenestrated and Branched Endografts: Assessment of Proximal Aortic Neck Fixation

PURPOSE

To investigate proximal fixation characteristics of different aortic endograft designs: a suprarenally placed fenestrated endograft, a modular branched endograft, an infrarenal endograft with suprarenal bare stent fixation, and the gold standard, a conventional hand-sewn anastomosis.

METHODS

Ten human cadaveric aortas were obtained at autopsy and transected 20 mm below the renal arteries to mimic an infrarenal aneurysm neck. In random order, the infrarenal, fenestrated, and branched endografts were deployed into the aorta. Using a hydraulic material testing machine, longitudinal load was applied to the distal end of each endograft until migration occurred, thus defining the displacement force (DF). Subsequently, a hand-sewn infrarenal anastomosis was tested in a similar manner.

RESULTS

The median DF was 4.67 N (3.82-6.37) for the infrarenal endograft, 9.17 N (8.03- 10.81) for the fenestrated endograft, and 16.95 N (14.78-19.67) for the branched endograft. The differences in DF between the infrarenal and fenestrated endografts and between the fenestrated and branched designs were statistically significant (both p=0.005). The median force to dislodge the graft from the conventional anastomosis was 89.16 N (71.24-105.23).

CONCLUSIONS

Suprarenally placed endografts, especially with additional branch grafts, provide improved proximal fixation compared to an infrarenal endograft with suprarenal bare stent fixation. However, none of the tested endografts approached the optimal, time-proven fixation, the hand-sewn anastomosis.

Transrenal fixation of aortic stent-grafts: current status and future directions

Aortic stent-graft repair has been widely used in clinical practice for more than a decade, achieving satisfactory results compared to open surgical techniques. Transrenal fixation of stent-grafts is designed to obtain secure fixation of the proximal end of the stent-graft to avoid graft migration and to prevent type I endoleak. Unlike infrarenal deployment of stent-grafts, transrenal fixation takes advantage of the relative stability of the suprarenal aorta as a landing zone for the uncovered struts of the proximal stent. These transostial wires have sparked concern about the patency of the renal arteries, interference with renal blood flow, and effects on renal function. Although short to midterm results with suprarenal stent-grafts have not shown significant changes in renal function, long-term effects of this technique are still not fully understood. This review will explore the current status of transrenal fixation of aortic stent-grafts, potential risks of stent struts relative to the renal ostium, alternative methods to preserve blood flow to the renal arteries, and future directions or developments in stent-graft design to prevent myointimal proliferation around the stent struts.

Suprarenal fixation of endograft in abdominal aortic aneurysm treatment: focus on renal function

OBJECTIVE

The objective of this work was to evaluate any variation of renal function detected by renal scintigraphy after the suprarenal fixation of endografts for abdominal aortic aneurysm (AAA) repair.

SUMMARY BACKGROUND DATA

In the few articles that have considered this problem, renal function was evaluated only by biochemical tests, which are inadequate in demonstrating small changes in renal function and in appreciating the worsening of a single kidney's function.

METHODS

Between April 1999 and May 2002, 47 patients with an inappropriate infrarenal proximal neck had a suprarenal fixation for AAA. To assess renal function, a technetium-99m diethylene triamine penta-acetic acid (TC-DTPA) perfusion scintigraphy was performed preoperatively on the third postoperative day and at 6, 12 months, and then yearly thereafter. Worsening of renal function was defined as a decrease of glomerular filtration rate (GFR) > or =20% (detected with Gates method). Serum creatinine level was tested preoperatively and at the first and third postoperative day.

RESULTS

Endograft deployment was technically successful in 44 patients (93.6%); clinical perioperative success was obtained in 46 patients (97.8%). In 12 patients (25.5%), a permanent reduction of the GFR was observed using postoperative TC-DTPA perfusion scintigraphy. By 99m TC-DTPA perfusion scintigraphy, a permanent reduction of GFR was observed postoperatively in 12 patients. A slight GFR reduction (<20%) was present in 7 (14.9%) patients, due to the planned occlusion of accessory renal arteries. A more significant GFR reduction (>20%) was present unexpectedly in 5 (10.6%) patients, in 3 of these a single kidney was involved, in 5 both with an increase of the serum creatinine level >20%.

CONCLUSIONS

Suprarenal fixation of endografts in AAA treatment is a safe procedure with good early and midterm procedural results and a risk of GFR impairment (>20%) of 10.6%.

Long-term renal function following endovascular aneurysm repair with infrarenal and suprarenal aortic stent-grafts

PURPOSE

To determine in a retrospective analysis the incidence of renal impairment (RI) following endovascular repair (EVR) of abdominal aortic aneurysm (AAA), to assess the morbidity and mortality in endograft patients with preoperative RI, and to examine the impact of suprarenal stent-grafts on renal function.

METHODS

From March 1994 to October 2001, 315 AAA patients (289 men; mean age 72.4+/-7.0 years) undergoing EVR were entered prospectively into a vascular registry. The patients received either an in-house custom-made stent-graft or one of several commercially made devices implanted with infrarenal or suprarenal fixation. Renal function was monitored by serum creatinine measurements prior to discharge and at 3, 6, and 12 months and annually thereafter. Preoperative RI was defined as a serum creatinine >130 micro mol/L and/or long-term dialysis. Postoperative RI referred to a >20% increase in the serum creatinine over baseline. Additional deterioration of renal function in patients with preoperative RI was referred to as postoperatively worsened RI.

RESULTS

Of the 315 patients treated, 220 (69.8%) were considered high risk (ruptured AAA or ASA grade III or IV). Sixty-nine (21.9%) patients had preoperative RI (6 [1.9%] on preoperative dialysis). A suprarenal stent-graft was used in 169 (53.7%) patients and infrarenal stent-graft in the remaining 146 (46.3%). The mean follow-up was 30.1+/-22.7 months. Postoperative RI occurred in 53 (16.8%) patients (24 [7.6%] transient, 29 [9.2%] persistent). Patients with preoperative RI had a significantly higher incidence of postoperatively worsened RI (37.7% versus 11.0%, p<0.0001) and a higher mortality related to RI (7.2% versus 1.6%, p=0.02). Suprarenal fixation had no influence on the incidence of RI, on perioperative mortality, or on mortality related to RI. The only significant predictive factor of postoperative RI was preoperative RI (risk ratio 5.09, 95% CI 2.38 to 10.87, p=0.0001).

CONCLUSIONS

Endovascular AAA repair may lead to persistent postoperative RI in nearly 10% of cases, especially in patients with preoperative RI. Suprarenal stent-graft fixation does not seem to have any deleterious effect on renal function. Further long-term studies are required to confirm the innocuous nature of transrenal stent placement.

Fate of branch arteries after intracranial stenting

OBJECTIVE

One concern with respect to stent procedures performed to treat patients with intracranial lesions is the fate of normal major arterial branches after stents are placed across them. Because most of these lesions occur at vessel bifurcations or at branch points, a normal major branch often arises near the lesion and may be difficult to avoid during stent positioning. The aim of this article is to describe the angiographic outcome of intracranial major branch arteries crossed by a stent in the intracranial circulation.

METHODS

We examined the immediate postprocedural cerebral angiograms of the 40 patients who underwent intracranial stenting at the University at Buffalo, Buffalo, NY, between June 1998 and April 2000. In each of 10 patients, the stent was placed across a normal major branch artery. Stents were used to treat aneurysms in seven patients and intracranial stenosis in three patients. The latest cerebral angiogram available was reviewed, and the patency of the major branch arteries was evaluated.

RESULTS

The angiographic follow-up period ranged from 4 days to 35 months (mean follow-up, 10 mo). Each of the 10 major branch arteries was patent. No infarcts were associated with the territory of the major branch arteries crossed by the stents, and no patient experienced a related episode of clinical ischemia. Four patients died as a result of causes unrelated to the stenting procedure. The histology of a middle cerebral artery stent that was placed across a lenticulostriate perforator is presented.

CONCLUSION

The flexible, low-profile stents used in this study had no angiographically or clinically apparent effect on the major intracranial branches across which they were placed.

Transrenal fixation of endovascular stent-grafts for infrarenal aortic aneurysm repair: mid-term results

PURPOSE

We evaluated mid-term results of a single-center consecutive series of endovascular stent-grafts implanted for aortic aneurysm repair with transrenal fixation, to determine clinical outcome, aneurysm anatomy, renal artery patency, and renal complications.

METHODS

Modular stent-grafts were placed with transrenal fixation in 37 patients between November 1998 and July 2000. Follow-up evaluation included clinical examination, laboratory evaluation of serum creatine concentration, computed tomographic angiography, and renal duplex scanning.

RESULTS

Thirty-seven patients underwent transrenal fixation of aortic stent-grafts as part of a Phase II US Food and Drug Administration study. Two patients subsequently underwent follow-up at institutions closer to their homes, and thus provided clinical information but no long-term renal or aneurysm morphologic data. There were no perioperative deaths. Five patients died during follow-up, at a mean of 9 months, because of myocardial infarction in 4 patients and respiratory failure in 1 patient. Thirty patients, ages 75 +/- 8 years, have been followed up for 28.5 +/- 7.2 months. Aneurysm diameter at follow-up was 5.0 +/- 0.8 cm, compared with 5.7 +/- 0.8 cm preoperatively. In 5 patients, endoleak developed during follow-up: 1 type I leak was treated with an aortic cuff, with temporary stabilization of the aneurysm and correction of the endoleak; 2 type II endoleaks were treated with translumbar coil embolization, and 1 resolved spontaneously; and 1 type III endoleak was treated with a combination of coil embolization and stent-graft extension to cover a graft defect. Preoperatively, serum creatinine concentration was normal in 23 patients, but increased persistently in 2 patients and was abnormal in 7 patients. Postoperatively, creatine concentration increased in 4 patients to greater than 20% of baseline level. Seventeen patients had no evidence of renal artery stenosis, compared with 13 patients with renal artery stenosis. Of 41 normal renal arteries, 90% remained unchanged, 1 became occluded, 3 demonstrated 60% stenosis. Nephrectomy was necessary in 1 patient because of cancer. Of 19 abnormal renal arteries, progression of disease was noted in 3 arteries.

CONCLUSIONS

Transrenal fixation of aortic stent-grafts can be performed with acceptable mid-term outcome with respect to mortality, need for follow-up intervention, and aneurysm exclusion with protection from rupture. Postprocedural stenosis can develop in both normal and abnormal renal arteries. Rate of progression of disease was greater in patients with preprocedural renal dysfunction compared with patients with normal renal arteries. This is merely an observation, and may not be related to transrenal fixation. Long-term follow up is needed.