Conformational changes associated with proximal seal zone failure in abdominal aortic endografts

Low profile endografts for the endovascular treatment of abdominal aortic aneurysms

INTRODUCTION

Favorable midterm outcomes have been reported with the use of low-profile endografts (LPE), but long-term data is still needed. Furthermore, it is unclear if each of these LPE may have advantages over the other, which may, in turn, affect the outcomes. We systematically reviewed the literature about complications and reintervention rates of patients submitted to endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) using LPE.

MATHERIALS AND METHODS

A literature search was conducted including articles that reported 30-days and follow-up mortality, complications, and reintervention rates of patients treated with EVAR using Incraft (Cordis), Zenith LP/Alpha (Cook Medical Inc) and Ovation (Endologix) endografts.

RESULTS

36 papers were evaluated, reporting results of 582 patients treated with Zenith device, 1211 with Incraft and 3449 with Ovation. During follow up, similar survival and freedom from reintervention rates were reported among the various types of endograft both at 1 and 3 years. The incidence of limb stenosis/kinking was significantly higher in patients treated with Zenith LP/Alpha (2.1%, P = 0.008), while the Incraft device had a significantly lower proportion of type III endoleaks (P < 0.001).

CONCLUSIONS

Long-term survival and freedom from reintervention rates were comparable among the three LPEs. The Cook Zenith device had the highest rates of limb stenosis/kinking, while the Incraft device had the lowest occurrence of type III endoleak.

PROSPERO

Registration number: CRD42022315875.

Surgical treatment patterns and clinical outcomes of patients treated for expanding aneurysm sacs with type II endoleaks after endovascular aneurysm repair

OBJECTIVE

Persistent type II endoleaks (T2ELs) after endovascular aneurysm repair (EVAR) with sac growth have been associated with adverse events, including rupture. Whereas intervention in the presence of aneurysm growth has become an accepted treatment paradigm for T2ELs, the efficacy and clinical success of such interventions remain unclear. Therefore, we examined the treatment patterns and clinical outcomes of patients undergoing T2EL interventions after EVAR.

METHODS

We performed a retrospective review of all patients treated for expanding aneurysm sacs with T2ELs after EVAR at an academic medical center between 2006 and 2017. The primary outcomes assessed were need for repeated intervention; intervention types; and achievement of clinical success, defined as stable aneurysm sac size on computed tomography angiography after treatment.

RESULTS

Fifty-six patients underwent 119 interventions, of which 107 (90%) were technically successful. The median time from EVAR to index T2EL procedure was 37 months (interquartile range, 17-56 months), and the median follow-up time from first T2EL procedure was 27 months (interquartile range, 10-51 months). The most common index procedure was transarterial lumbar embolization (64%), followed by transarterial inferior mesenteric artery (20%), transcaval (14%), and translumbar embolization (1.8%). Thirty-three (59%) patients required further procedures for persistent aneurysm sac expansion. For subsequent T2EL interventions, the most common endovascular procedure was transarterial lumbar embolization (21%), followed by transcaval (21%), translumbar (11%), and transarterial inferior mesenteric artery embolization (8.6%). Twelve patients (21%) were found to have loss of proximal or distal seal on subsequent imaging and required graft extensions to stabilize aneurysm sac size. Ten patients (18%) ultimately underwent graft explantation or sacotomy with oversewing of the endoleak source. Freedom from any endoleak-related reintervention was 57% at 1 year and 36% at 3 years. Freedom from open treatment was 93% at 1 year and 82% at 3 years. Of the 44 patients with ≥6-month follow-up, 39 (89%) achieved clinical success. However, only 11 patients (25%) achieved clinical success without any further reintervention, and 29 patients (66%) achieved clinical success without open treatment.

CONCLUSIONS

Despite high technical success, endoleak recurrence after T2EL treatment is common, and multiple interventions are often needed to stabilize aneurysm sac size in patients diagnosed with T2EL-associated sac growth. Notably, one in five patients treated for T2ELs was discovered, on further evaluation, to have proximal or distal seal zone loss that necessitated repair to achieve sac stability. Thus, thorough assessment of all endoleak types should be performed in patients with T2ELs associated with sac growth before T2EL treatment to ensure appropriate care and to minimize ineffective interventions.

Endograft Conformability in Fenestrated Endovascular Aneurysm Repair for Complex Abdominal Aortic Aneurysms

Purpose: To compare the impact of 2 commercially available custom-made fenestrated endografts on patient anatomy. Materials and Methods: The records of 234 patients who underwent fenestrated endovascular aneurysm repair for abdominal aortic aneurysm from March 2002 to July 2016 in 2 hospitals were screened to identify those who had pre- and postoperative computed tomography angiography assessments with a slice thickness of ≤2 mm. The search identified 145 patients for further analysis: 110 patients (mean age 72.4±7.1 years; 94 men) who had been treated with the Zenith Fenestrated (ZF) endograft and 35 patients (mean age 72.3±7.3 years; 30 men) treated with the Fenestrated Anaconda (FA) endograft. Measurements included aortic diameters at the level of the superior mesenteric artery (SMA) and renal arteries, target vessel angles, target vessel clock positions, and the target vessel tortuosity index. Variables were tested for inter- and intraobserver agreement. Results: There was a good agreement between observers in all tested variables. The native anatomy changed in both groups after endograft implantation. In the ZF group, changes were seen in the angles of the celiac artery (p=0.012), SMA (p=0.022), left renal artery (LRA) (p<0.001), and the right renal artery (RRA) (p<0.001); the aortic diameter at the SMA level (p<0.001); and the LRA (p<0.001) and RRA (p<0.001) clock positions. In the FA group, changes were seen in the angles of the LRA (p=0.001) and RRA (p<0.001) and in the SMA tortuosity index (p=0.044). Between group differences in changes were seen for the aortic diameters at the SMA and renal artery levels (p<0.001 for both) and the LRA clock position (p=0.019). Conclusion: Both custom-made fenestrated endografts altered vascular anatomy. The data suggest a higher conformability of the Fenestrated Anaconda endograft compared with the Zenith Fenestrated.

Kilt Technique as an Angle Modification Method for Endovascular Repair of Abdominal Aortic Aneurysm with Severe Neck Angle

PURPOSE

Kilt technique can be useful for overcoming the severe angle in endovascular abdominal aortic repair. Thus, we investigate the utility of the Kilt technique as an angle modification method.

METHODS

This study included 16 patients with abdominal aortic aneurysm having severe neck angle (over 60°). Of these, eight were treated using Kilt technique, whereas the remaining eight were by the conventional endovascular method. We investigated the pre- and post-procedural differences in neck angle between the two groups using aortic computed tomography (CT) angiography.

RESULTS

Mean pre-procedural neck angles in the conventional group and the Kilt group were 70° ± 13° and 93° ± 14° (p = 0.007) and supra-renal neck angles were 54° ± 16° and 89° ± 26°, respectively (p = 0.016). However, the angle differences disappeared between the two groups after the procedure. Consequently, the Kilt group showed greater angle change than the conventional group (p value for ∆ supra-renal angle and ∆ neck angle were 0.015 and 0.021, respectively). There was no type 1 endoleak during 16 ± 16 months of CT follow-up.

CONCLUSION

Kilt technique may be an effective tool for modifying the neck angle without leaving increased risk of type 1 endoleak in this subset of patients.

Is Neck Dilatation After Endovascular Aneurysm Repair Graft Dependent?

Long-term success of endovascular aneurysm repair (EVAR) relies on a stable proximal neck. The authors' goal was to determine whether neck dilatation after EVAR varies among 4 different endografts and whether it is related to complications of the proximal neck. Core laboratory data from 4 phase II trials of aortic endografts were analyzed for neck diameter changes over time. Patients who had at least 24 months' follow-up were included in the analysis. Neck measurement methodology varied among the 3 core labs used. Values are reported within the parameters used by each lab. Short-axis neck diameter close to 5 mm below the renal arteries, when available, was used for longitudinal comparisons. Dilation was defined as an enlargement of 3 mm or more from the first postoperative scan to the last available follow-up for each patient. Graft migration and late proximal endoleaks were determined by the individual core labs. A limited number of Lifepath grafts had most recent follow-up measurements performed by the authors. Results were compared by using Student's t test, chi-square analysis, and the Pearson correlation coefficient. Postoperative measurements from 729 EVAR patients were examined. Follow-up ranged from 24 to 60 months for 229 Ancure (Guidant) and 258 AneuRx (Medtronic) patients, and from 24 to 36 months for 211 Excluder (Gore) and 31 first-generation Lifepath (Edwards) patients. Neck dilation was noted in 124 patients (17.0%) and did not differ significantly among graft types. The incidences of late proximal endoleaks were similar among graft types, but rates of migration differed (p= 0.01). Dilation was associated with migration in Ancure (p=0.03) and Excluder (p=0.02) grafts. Late proximal endoleaks were seen in 4.1% of patients with and in 0.7% of patients without dilation (p=0.001). Patients with initial neck diameter >25 mm had significantly less dilatation than those with smaller necks (p<0.001). The incidence of neck dilation approached 20% in all EVAR patients after 24 months and was not significantly different among graft types. Neck dilation of 3 mm or more appears to be one risk factor for migration and late proximal endoleak.

Use of Proximal Aortic Cuffs as an Adjunctive Procedure during Endovascular Aortic Aneurysm Repair

The purpose of this study was to evaluate the incidence and durability of additional proximal cuffs during endovascular abdominal aortic aneurysm repair (EVAR). A retrospective review of 90 EVAR patients was conducted. Postoperative survival, proximal sealing zone–related complications, and secondary procedures were analyzed.

Additional proximal cuffs were used in 11%. Their use did not affect postoperative survival ( p = .58), type I endoleak rate (4.4%; p = .19), or the need for sealing zone–related secondary procedures (6.3%; p = .38) compared with patients without cuff placement but was related to a higher cumulative graft migration rate (2.2% overall p = .02). Two patients (2.5%; p = .79) underwent conversion to open surgery, both for proximal sealing zone–related complications.

Application of proximal cuffs appears to be an effective intraoperative adjunctive procedure to achieve a proximal seal during EVAR, with favorable midterm results. However, the risk of late endograft migrations may be elevated in this group.

Effect of curvature on displacement forces acting on aortic endografts: a 3-dimensional computational analysis

PURPOSE

To determine the effect of curvature on the magnitude and direction of displacement forces acting on aortic endografts in 3-dimensional (3D) computational models.

METHOD

A 3D computer model was constructed based on magnetic resonance angiography data from a patient with an infrarenal aortic aneurysm. Computational fluid dynamics tools were used to simulate realistic flow and pressure conditions of the patient. An aortic endograft was deployed in the model, and the displacement forces acting on the endograft were calculated and expressed in Newtons (N). Additional models were created to determine the effects of reducing endograft curvature, neck angulation, and iliac angulation on displacement forces.

RESULTS

The aortic endograft had a curved configuration as a result of the patient's anatomy, with curvature in the anterolateral direction. Total displacement force acting on the endograft was 5.0 N, with 28% of the force in a downward (caudal) direction and 72% of the force in a sideways (anterolateral) direction. Elimination of endograft curvature (planar graft configuration) reduced total displacement force to 0.8 N, with the largest component of force (70%) acting in the sideways direction. Straightening the aortic neck in the curved endograft configuration reduced the total force acting on the endograft to 4.2 N, with a reduction of the sideways component to 55% of the total force. Straightening the iliac limbs of the endograft reduced the total force acting on the endograft to 2.1 N but increased the sideways component to 91% of the total force.

CONCLUSION

The largest component of the force acting on the aortic endograft is in the sideways direction, with respect to the blood flow, rather than in the downward (caudal) direction as is commonly assumed. Increased curvature of the aortic endograft increases the magnitude of the sideways displacement force. The degree of angulation of the proximal and distal ends of the endograft influence the magnitude and direction of displacement force. These factors may have a significant influence on the propensity of endografts to migrate in vivo.

Iliac fixation inhibits migration of both suprarenal and infrarenal aortic endografts

OBJECTIVE

To evaluate the role of iliac fixation in preventing migration of suprarenal and infrarenal aortic endografts.

METHODS

Quantitative image analysis was performed in 92 patients with infrarenal aortic aneurysms (76 men and 16 women) treated with suprarenal (n = 36) or infrarenal (n = 56) aortic endografts from 2000 to 2004. The longitudinal centerline distance from the superior mesenteric artery to the top of the stent graft was measured on preoperative, postimplantation, and 1-year three-dimensional computed tomographic scans, with movement more than 5 mm considered to be significant. Aortic diameters were measured perpendicular to the centerline axis. Proximal and distal fixation lengths were defined as the lengths of stent-graft apposition to the aortic neck and the common iliac arteries, respectively.

RESULTS

There were no significant differences in age, comorbidities, or preoperative aneurysm size (suprarenal, 6.0 cm; infrarenal, 5.7 cm) between the suprarenal and infrarenal groups. However, the suprarenal group had less favorable aortic necks with a shorter length (13 vs 25 mm; P < .0001), a larger diameter (27 vs 24 mm; P < .0001), and greater angulation (19 degrees vs 11 degrees ; P = .007) compared with the infrarenal group. The proximal aortic fixation length was greater in the suprarenal than in the infrarenal group (22 vs 16 mm; P < .0001), with the top of the device closer to the superior mesenteric artery (8 vs 21 mm; P < .0001) as a result of the 15-mm uncovered suprarenal stent. There was no difference in iliac fixation length between the suprarenal and infrarenal groups (26 vs 25 mm; P = .8). Longitudinal centerline stent graft movement at 1 year was similar in the suprarenal and infrarenal groups (4.3 +/- 4.4 mm vs 4.8 +/- 4.3 mm; P = .6). Patients with longitudinal centerline movement of more than 5 mm at 1 year or clinical evidence of migration at any time during the follow-up period comprised the respective migrator groups. Suprarenal migrators had a shorter iliac fixation length (17 vs 29 mm; P = .006) and a similar aortic fixation length (23 vs 22 mm; P > .999) compared with suprarenal nonmigrators. Infrarenal migrators had a shorter iliac fixation length (18 vs 30 mm; P < .0001) and a similar aortic fixation length (14 vs 17 mm; P = .1) compared with infrarenal nonmigrators. Nonmigrators had closer device proximity to the hypogastric arteries in both the suprarenal (7 vs 17 mm; P = .009) and infrarenal (8 vs 24 mm; P < .0001) groups. No migration occurred in either group in patients with good iliac fixation. Multivariate logistic regression analysis revealed that iliac fixation, as evidenced by iliac fixation length (P = .004) and the device to hypogastric artery distance (P = .002), was a significant independent predictor of migration, whereas suprarenal or infrarenal treatment was not a significant predictor of migration. During a clinical follow-up period of 45 +/- 22 months (range, 12-70 months), there have been no aneurysm ruptures, abdominal aortic aneurysm-related deaths, or surgical conversions in either group.

CONCLUSIONS

Distal iliac fixation is important in preventing migration of both suprarenal and infrarenal aortic endografts that have longitudinal columnar support. Secure iliac fixation minimizes the risk of migration despite suboptimal proximal aortic neck anatomy. Extension of both iliac limbs to cover the entire common iliac artery to the iliac bifurcation seems to prevent endograft migration.

Retrograde migration of an abdominal aortic aneurysm endograft leading to postoperative renal failure

The phenomenon of antegrade (distal) endograft migration is an extensively documented complication after endovascular abdominal aortic aneurysm repair. This case report describes the finding of postoperative abdominal aortic aneurysm endograft retrograde (proximal) migration occluding bilateral renal arteries and leading to dialysis-dependent renal failure.

Stent-Graft Migration:A Reappraisal of Analysis Methods and Proposed Revised Definition

PURPOSE

To demonstrate the need for a radiographic definition of migration that accurately describes a specific failure mode of an aortic stent-graft.

METHODS

The diagnosis of endograft migration, as defined by the Society for Vascular Surgery/American Association for Vascular Surgery (SVS/AAVS) standards, requires a synthesis of clinical and/or radiographic observations. Radiographic studies and clinical reports of 704 consecutive patients treated over a 6-year period with abdominal aortic endografts were retrospectively reviewed. According to the current SVS/AAVS standards, 25 patients were identified as having endograft migration. Follow-up computed tomographic scans and radiographs available for 24 of these patients were scrutinized from discharge to the time of any observed proximal or distal fixation system movement based upon the discharge or 30-day CT scan. Proximal migration was defined with respect to the origin of the superior mesenteric artery (SMA) as movement in a caudal or cranial direction of >/=10 mm or >2 times the reconstructed resolution of the imaging study (whichever measurement was less). Distal migration was similarly defined using the aortic bifurcation and respective hypogastric artery origin as reference points. In an effort to assess the scan-to-scan variation, the distance between the SMA and lowest renal artery, which was expected to remain consistent, was measured.

RESULTS

Film analysis with application of the revised migration definition confirmed fixation system failure with respect to the native arterial system in 12 (50%) of the 24 patients. Subjects judged to have endograft migration according to the reporting standards but not to have radiographic evidence of migration based on the modified criteria included 2 proximal endoleaks without evidence of device movement treated with proximal extensions, 1 procedure-related migration, 2 type III endoleaks treated with a second prosthesis implanted within the first, 1 distal endoleak treated with a limb extension, 1 rupture with presumed distal limb migration, and 2 cases of component separation. Three limb extensions were placed in the absence of leak or migration. These 12 patients all had radiographic evidence that the proximal and distal aspects of the originally implanted device did not move with respect to the native arterial vasculature, thus confirming stability of the respective fixation system.

CONCLUSIONS

Adherence to this comprehensive definition of device migration, which differs from the published reporting standards, allows differentiation of the specific mechanisms of device failure. Data viewed in this context will aid in the understanding of device strengths and weaknesses, potentially improve patient assessment, and encourage design modifications to address specific aspects relating to fixation failure.

Treatment of short-necked infrarenal aortic aneurysms with fenestrated stent-grafts: short-term results

INTRODUCTION

A proximal neck of 15 mm length is usually required to allow endovascular repair of abdominal aortic aneurysms (EVAR). Many patients have been refused EVAR due to a short neck. By customising fenestrated grafts to the patients' anatomy, we can offer an endovascular solution, especially for patients who are unsuitable for open repair.

METHODS

Eighteen patients were selected for fenestrated stent-grafting if they presented with an abdominal aneurysm of at least 55 mm in diameter, a short neck (less than 15 mm), plus contra-indications for open repair (cardiopulmonary impairment or a hostile abdomen). The stent-graft used was a customised fenestrated model based on the Cook Zenith composite system. We used additional stents to ensure apposition of the fenestrations with the side branches.

RESULTS

All endovascular procedures were successful. Out of the 46 targeted side branches (10 superior mesenteric arteries, 36 renal arteries), 45 were patent at the end of the procedure. One accessory renal artery became occluded by the stent-graft. There was one possible proximal type I endoleak, which later proved to be a type II endoleak. There was no mortality, but complications occurred in six patients: two cardiac complications, three urinary complications and one occlusion of a renal artery. At follow-up (mean 9.4 months, range 1-18), there were no additional renal complications and all the remaining targeted vessels stayed patent.

DISCUSSION

By customizing fenestrated stent-grafts, it is possible to position the first covered stent completely inside the proximal neck, thus achieving a more stable position. The additional side-stents may also contribute to a better fixation. This technique may become a valuable alternative for patients who are at high risk from open surgery.

Perirenal Fixation as an Independent Factor in Aortic Remodeling after Endovascular Aortic Aneurysm Repair

The purpose of our study was to evaluate the influence of perirenal fixation of endovascular aortic grafts on the rate of endoleak and aortic sac remodeling. Retrospective analysis of all patients (pts.) after undergoing endovascular aortic aneurysm repair (EVAR) at our institution was performed. Pre- and postoperative aortic dimensions were obtained from CT scans and angiograms. Intraoperative angiograms were reviewed and patients grouped by the proximity of the graft to the lowest renal arteries: group I: flush with the lowest renal artery; group II: < or = 5 mm distal to lowest renal artery; and group III: >5 mm distal to lowest renal artery. Of the 96 grafts placed between 2000 and 2002, 44 were AneuRx (Medtronic, Santa Rosa, CA) and 52 were Ancure (Guidant, Menlo Park, CA) devices. There were 39 pts. in group I, 42 in group II, and 11 in group III (data on 5 pts. were not obtained). At 6 months, the mean decrease in sac diameter for all groups was 0.42 +/- 0.08 cm (1: 0.56 +/- 0.11 cm; 11: 0.38 +/- 0.11 cm; III: 0.6 +/- 0.15 cm). There was no significant difference between each group. When perirenal fixation (group I) was compared with nonperirenal fixation (groups II and III), there was a significant difference in sac shrinkage at 6 months (p < 0.05, ANOVA). Group I had shorter necks and smaller aneurysms (2.2 +/- 0.1 cm and 5.3 +/- 0.1 cm) than those of groups II and III (2.7 +/- 0.1 cm and 5.7 +/- 0.1 cm, p < 0.05, ANOVA). There was no difference in aortic neck diameter or in aortic neck diameter to graft ratio. When controlled for the variables studied (AAA diameter, length of neck, diameter of neck, diameter of neck to graft ratio, and any endoleak by 6 months), logistic regression analysis identified perirenal fixation as the only significant factor in aortic sac shrinkage of >0.4 cm by 6 months (odds ratio = 16, p < 0.01). With the same variables, a linear regression model also identified perirenal fixation as the only predictive factor in aortic shrinkage (regression coefficient = 0.46, p < 0.05). The endoleak-free survival rate with perirenal fixation was 96 +/- 5% and without it was 80 +/- 7% (Kaplan Meier, p = 0.09, log rank). Perirenal placement of endovascular grafts is associated with a trend toward fewer endoleaks, and improved aortic sac shrinkage independent of aortic neck length, AAA diameter, diameter of neck, and endoleak. Failure to achieve perirenal placement of EVAG increased the likelihood of reduced or failed aortic sac shrinkage in this series.

Stent graft migration after endovascular aneurysm repair: importance of proximal fixation

OBJECTIVE

We reviewed the incidence of stent-graft migration after endovascular aneurysm repair in a prospective multicenter trial and identified factors that may predispose to such migration.

METHODS

All patients who received treatment during the course of the multicenter AneuRx clinical trial were reviewed for evidence of stent-graft migration over 5 years, from 1996 to 2001. Post-deployment distance from the renal arteries to the proximal end of the stent graft and the proximal fixation length (length of the infrarenal neck covered by the stent graft) were determined in patients for whom pre-procedure and post-procedure computed tomography scans were measured in an independent core laboratory.

RESULTS

Stent-graft migration was reported in 94 of 1119 patients, with mean time after device implantation of 30 +/- 11 months. Freedom from migration was 98.6% at 1 year, 93.4% at 2 years, and 81.2% at 3 years (Kaplan-Meier method). Subset (n = 387) analysis revealed that initial device deployment was lower in 47 patients with migration, as evidenced by a greater renal artery to stent-graft distance (1.1 +/- 0.7 cm), compared with 340 patients without migration (0.8 +/- 0.6 cm; P =.006) on post-implantation computed tomography scan. Proximal fixation length was shorter in patients with migration (1.6 +/- 1.4 cm) compared with patients without migration (2.3 +/- 1.4 cm; P =.005). There was significant variation in migration rate among clinical sites (P <.001), ranging from 0% to 30% (median, 8%), with a greater than twofold difference in migration rate between the lowest quartile (6%) and the highest quartile (15%) clinical sites. Univariate and multivariate analysis revealed that renal artery to stent-graft distance (P =.001) and proximal fixation length (P =.005) were significant predictors of migration, and that each millimeter increase in distance below the renal arteries increased risk for subsequent migration by 5.8% and each millimeter increase in proximal fixation length decreased risk for migration by 2.5%. Pre-implantation aortic neck length, neck diameter, degree of device oversizing, correct versus incorrect oversizing, device type (stiff vs flexible), placement of proximal extender cuffs at the original procedure, and post-procedure endoleak were not significant predictors of migration. Migration was treated with placement of extender modules in 23 patients and surgical conversion in 7 patients; 64 patients (68%) with migration have required no treatment.

CONCLUSIONS

Stent-graft migration among patients treated in the AneuRx clinical trial appears to be largely related to low initial deployment of the device, below the renal arteries, and short proximal fixation length. Significant variation in migration rate among clinical sites highlights the importance of the technical aspects of stent-graft deployment. Advances in intraoperative imaging and deployment techniques that have been made since completion of the clinical trial facilitate precision of device placement below the renal arteries and should increase proximal fixation length. Whether this, together with increased iliac fixation length, will result in lower risk for migration remains to be determined in long-term follow-up studies.

Does transrenal fixation of aortic endografts impair renal function?

OBJECTIVES

Transrenal fixation (TFX) of aortic endografts is thought to increase the risk for renal infarction and impaired renal function. We studied the late effects of TFX on renal function and perfusion.

METHODS

Of 189 patients with commercial aortic endografts, which we inserted between 1995 and 2002, we reviewed data for 130 patients (112 men, 18 women) with available creatinine (Cr) concentration and contrast enhanced computed tomography (CT) scans preoperatively and 1 to 97 months after the procedure. Of the 130 patients, 69 patients had TFX and 61 patients had infrarenal fixation (IFX). Both groups were physiologically comparable. Average age was 76 +/- 8 years for patients with TFX and 75 +/- 8 years for patients with IFX. Presence of renal infarct or renal artery occlusion was determined by nephrograms on serial contrast-enhanced CT scans.

RESULTS

Mean follow-up was 17 +/- 16 months (range, 1-54 months) for TFX and 21 +/- 21 months (range, 1-97 months) for IFX. Mean serum Cr concentration increased significantly during long-term follow-up in both groups (TFX, 1.3 +/- 0.5 mg/dL to 1.5 +/- 0.8 mg/dL, P <.01; IFX, 1.3 +/- 0.7 mg/dL to 1.4 +/- 0.8 mg/dL, P <.03). Creatinine clearance (CrCl) similarly decreased over long-term follow-up in both groups (TFX, 53.3 +/- 17.7 mL/min/1.73 m(2) to 47.9 +/- 16.2 mL/min/1.73 m(2), P <.01; IFX, 58.1 +/- 22.7 mL/min/1.73 m(2) to 53.1 +/- 23.4 mL/min/1.73 m(2), P <.02). There were no significant differences in the increase in Cr concentration (P =.19) or decrease in CrCl (P =.68) between TFX and IFX groups. Small renal infarcts were noted in four patients (5.8%) in the TFX group and one patient (1.6%) in the IFX group. No increase in Cr concentration or decrease in CrCl was noted in any patient with a renal infarct. Postoperative renal dysfunction developed in 7 of 69 patients (10.1%) in the TFX group and 7 of 61 patients (11.5%) in the IFX group. There were no statistically significant differences between groups with respect to number of patients with new renal infarcts (P =.37) or postoperative renal dysfunction (P =.81).

CONCLUSION

There is a slight increase in serum Cr concentration and decrease in CrCl after aortic endografting. However, there was no significant difference in these changes between patients with TFX and IFX. Although TFX may produce a higher incidence of small renal infarcts, these do not impair renal function. Thus our midterm results suggest that TFX can be performed safely, with no greater change in renal function than observed after IFX.