Results of endoluminal grafting of abdominal aortic aneurysms are dependent on aneurysm morphology

Endoluminal Repair of Abdominal Aortic Aneurysms: Strengths and Weaknesses of Various Prostheses Observed in a 4.5-Year Experience

Purpose:

To summarize the results of endovascular abdominal aortic aneurysm (AAA) treatment using several endograft designs over a 4.5-year experience and offer comparisons on the various devices.

Methods:

From May 1992 to August 1996, 121 AAA patients meeting the criteria for an endoluminal repair were treated with 1 of 5 endograft designs in three configurations. The endografts were implanted in the operating room under fluoroscopic control. Follow-up included contrast-enhanced computed tomography within 10 days of operation, 6 months postoperatively, and annually thereafter.

Results:

Endografts were successfully deployed in 106 patients (88%). Fifteen cases were converted to open repair. Six procedure-related deaths occurred within 30 days owing to myocardial infarction (3), combined renal failure and septicemia (2), and multisystem failure (1). There were 36 local/vascular complications (30%) and 18 systemic/remote complications (15%). Of the 121 patients undergoing endoluminal AAA repair, 93 (77%) are currently alive and well with their AAAs excluded from the circulation.

Conclusions:

Trends in endoluminal AAA repair and prosthetic design point toward simpler devices and earlier treatment of smaller aneurysms once the long-term outcome of aortic endografting has been determined.

Shortening of Endografts during Deployment in Endovascular AAA Repair

Purpose:

To evaluate the incidence and extent of length changes during implantation of endovascular grafts in a prospective study of patients undergoing endovascular abdominal aortic aneurysm (AAA) repair.

Methods:

Data regarding the occurrence of intraoperative technical difficulties and device complications were recorded prospectively for the Vanguard or AneuRx self-expanding, bifurcated endovascular grafts in 64 patients (56 males; mean age 75 years). Graft length was measured in the sheath system before deployment and again immediately after deployment by fluoroscopic comparison to a graduated marking catheter.

Results:

Graft shortening ≥ 15 mm was documented in 22 (56%) of 39 Vanguard cases and 11 (44%) of 25 AneuRx endografts. Additional extension grafts were required to correct endoleak caused by inadequate graft length in 9 (14%) patients, but no conversion to open repair was necessary.

Conclusions:

There appears to be a high incidence of intraprocedural graft shortening with 2 current designs of self-expanding endoluminal grafts.

Endovascular aneurysm repair: current and future status

Endovascular aneurysm repair has rapidly expanded since its introduction in the early 1990s. Early experiences were associated with high rates of complications including conversion to open repair. Perioperative morbidity and mortality results have improved but these concerns have been replaced by questions about long-term durability. Gradually, too, these problems have been addressed. Challenges of today include the ability to roll out the endovascular technique to patients with adverse aneurysm morphology. Fenestrated and branch stent-graft technology is in its infancy. Only now are we beginning to fully understand the advantages, limitations, and complications of such technology. This paper outlines some of the concepts and discusses the controversies and challenges facing clinicians involved in endovascular aneurysm surgery today and in the future.

Conversion to open surgery after endovascular abdominal aortic aneurysms repair

The authors describe experience with conversions to open surgery after endovascular abdominal aneurysm repair and evaluate the frequency, causes and results of a total of 7 cases in their series of 165 patients treated over a 10-year period.

Surgical corrections of endovascular aneurysms: repair complications

The authors describe their experience with the use of 21 open surgical corrections after endovascular abdominal aneurysm repair, reporting the frequency, type and outcome of these procedures in their group of 165 patients treated during a 10-year period.

Access sites to vascular system for endovascular abdominal aortic aneurysms repair

The authors describe their experience with access sites for endovascular abdominal aortic aneurysm repair in a group of 165 patients treated over a 10-year period.

ENDOVASCULAR ABDOMINAL AORTIC ANEURYSM REPAIR: A 7 YEAR EXPERIENCE AT THE LAUNCESTON GENERAL HOSPITAL

BACKGROUND

To review our 7 year experience of endovascular abdominal aortic aneurysm repair (EVR) and to compare this to open repair (OR) during the same time period.

METHODS

One hundred and one EVR and 65 OR patients were studied. Parameters analysed included patient and procedure details, intensive care unit (ICU) and hospital admission time, and morbidity and mortality with particular emphasis on procedure-related problems.

RESULTS

Endovascular grafts were deployed with successful abdominal aortic aneurysm (AAA) exclusion in 100 patients. Primary technical success was achieved in 84%, clinical success in 86% and secondary success in 90% of cases. Complications occurred in 63% and 88% of EVR and OR patients, respectively. Early device-related complications occurred in 40 EVR patients (40%); 24 (60%) were corrected immediately by further stenting. Late device-related complications occurred in 15 EVR patients (15%); four (27%) required additional stenting. Most of the complications in the OR group were systemic (89%) resulting in longer ICU and hospital stays (median 48 vs 17 h and 13 vs 4 days for OR and EVR, respectively). Death within 30 days of the procedure occurred in three EVR patients. There was no perioperative mortality in the OR group.

CONCLUSION

Endovascular AAA repair can be undertaken successfully in a district general hospital. The majority of local and device-related complications can be corrected immediately, while those persisting beyond the initial procedure usually resolve spontaneously. EVR offers a minimally invasive approach to a problem that in the past has involved major surgery.

Abdominal aortic aneurysms: virtual imaging and analysis through a remote web server

The study describes the application of a web-based software in the planning of the endovascular treatment of abdominal aortic aneurysms (AAA). The software has been developed in the framework of a 2-year research project called Aneurysm QUAntification Through an Internet Collaborative System (AQUATICS); it allows to manage remotely Virtual Reality Modeling Language (VRML) models of the abdominal aorta, derived from multirow computed tomography angiography (CTA) data sets, and to obtain measurements of diameters, angles and centerline lengths. To test the reliability of measurements, two radiologists performed a detailed analysis of multiple 3D models generated from a synthetic phantom, mimicking an AAA. The system was tested on 30 patients with AAA; CTA data sets were mailed and the time required for segmentation and measurement were collected for each case. The Bland-Altman plot analysis showed that the mean intra- and inter-observer differences in measures on phantoms were clinically acceptable. The mean time required for segmentation was 1 h (range 45-120 min). The mean time required for measurements on the web was 7 min (range 4-11 min). The AQUATICS web server may provide a rapid, standardized and accurate tool for the evaluation of AAA prior to the endovascular treatment.

Intraoperative management: endovascular stents

This article discusses the current state of minimally invasive treatment options for a variety of vascular diseases. Advances that have been introduced over the last two decades have dramatically changed the practice of vascular surgery and anesthesia. The ability to treat pathology, using both intraluminal and extraluminal means,has provided vascular surgeons, interventional radiologists, and cardiologists with unique treatment options that were not available less than a decade ago. Peripheral interventions to treat vascular disease have exploded, from 90,000 in 1994 to more than 200,000 in 1997, and endovascular procedures now replace almost 50% of traditional open vascular operations.

Disparate outcome after endovascular treatment of small versus large abdominal aortic aneurysm

OBJECTIVES

The size of an abdominal aortic aneurysm is the most important parameter for determining whether repair is appropriate. This decision, however, must be considered in the context of long-term outcome of treatment, balancing risk for rupture with mortality from the initial procedure and all subsequent secondary procedures necessary when durability is not ideal. Information on the results of endovascular repair of small versus large aneurysms has not been available.

METHODS

Preoperative imaging studies and postoperative outcome were assessed in 700 patients who underwent endovascular repair of abdominal aortic aneurysm over 6 years at a single institution. Patients were divided into two groups: 416 patients (59.4%) with aneurysms smaller than 5.5 cm in diameter and 284 patients (40.6%) with aneurysms 5.5 cm or larger in diameter. Outcome variables were assessed with the Kaplan-Meier method and the log-rank test.

RESULTS

Patients with small and large aneurysms were comparable with regard to all baseline parameters assessed, with the single exception of a small increase in age (2.3 years) in patients with large aneurysms (P =.031). While there were no differences in rate of type II endoleaks, mid-term changes in sac diameter, or aneurysm rupture between the two groups, at 24 months patients with large aneurysms had more type I leaks (6.4% +/- 2.3% vs 1.4% +/- 0.6%; P =.011), device migration (13% +/- 4.0% vs 4.4% +/- 1.8%; P =.006), and conversion to open surgical repair (8.2% +/- 3.2% vs 1.4% +/- 1.1%; P =.031). Of greatest importance, at 24 months patient survival was diminished (71% +/- 4.6% vs 86% +/- 2.8%; P <.001) and risk for aneurysm-related death was increased (6.1% +/- 2.6% vs 1.5% +/- 1.0%; P =.011) in the group with large aneurysms.

CONCLUSIONS

Outcome after endovascular repair of abdominal aortic aneurysm depends on size; results appear inferior in patients with larger aneurysms. These differences attain importance when choosing between observation and repair, balancing risk for rupture against size-dependent outcome.

Mortality and morbidity following endovascular repair of abdominal aortic aneurysms: analysis of two single centre experiences

OBJECTIVE

to show how differences in anatomical and physiological risk factors can affect the outcome of endovascular repair of AAA by describing the experience of two centres with different selection policies.

METHODS

one hundred and thirty-five patients (group I) were treated at Queen's Medical Centre (Nottingham, U.K.) using 101 in-house made and 34 manufactured stent-grafts. Median diameter, length and angulation of the proximal aneurysm neck were 26 mm, 27 mm, 40 degrees, respectively. Seventy-six patients had ischaemic heart disease, 47 had left ventricular failure, median forced expiratory volume in one second (FEV1) was 83%, median creatinine was 100 micromol/l and median age was 72 years. Fifty patients (group II) were treated at Timone Hospital (Marseilles, France) using seven in-house made and 43 manufactured stent-grafts. Median diameter, length and angulation of the proximal aneurysm neck were 25 mm, 34 mm, 33 degrees, respectively. Thirteen patients had ischaemic heart disease, two had left ventricular failure, median forced expiratory volume in one second was 101%, median creatinine was 108 micromol/l and mean age was 72 years.

RESULTS

anatomical characteristics of the proximal neck were significantly worse in group I (p=0.02 for the three variables). Cardiac comorbidities were more frequent and mean FEV1 was lower in group I (p<0.0001 and p=0.001, respectively. Median aneurysm diameter was significantly greater in group I (65 mm) than in group II (53 mm) (p<0.001). Postoperative mortality was 9% and 0% in groups I and II respectively (p=0.03). The incidence of technical complications (groin wound complications and side branches endoleaks being excluded) was 20% and 0% in groups I and II, respectively (p=0.0006).

CONCLUSION

postoperative mortality and technical complication rates were significantly greater in group I than in group II, readily explained by poorer general condition and worse anatomical characteristics of the proximal neck in group I.

Which factors increase the risk of conversion to open surgery following endovascular abdominal aortic aneurysm repair? The EUROSTAR collaborators

OBJECTIVE

to identify factors that increase the risk of conversion to open surgery following endovascular repair of abdominal aortic aneurysms (AAAs) and to assess their outcome. Design analysis of 1871 patients enrolled in the EUROSTAR collaborators registry.

MATERIALS AND METHODS

patient characteristics, anatomic features of the aneurysm, type of endovascular device, institutional experience and the year in which the procedure was performed were related to risk of conversion.

RESULTS

forty-nine patients (2.6%) required conversion. In 38 patients conversion was performed during the first postoperative month (primary conversions) and in 11 patients during follow-up (secondary conversions). Primary conversion was mostly due to access problems and device migration. Secondary conversions were performed for rupture in six and for a persistent endoleak, with or without aneurysmal growth, in five patients. Patients who were converted were significantly older, had a lower body weight, and had a higher prevalence of chronic obstructive pulmonary disease. Conversion was associated with shorter, wider infrarenal necks and larger aneurysms. The conversion rate was lower when a team had performed more than 30 procedures, and in procedures performed during the last two years of the study period. The conversion rate was higher with EVT or Talent devices. Patients who required primary conversion had an 18% mortality rate, compared to 2.5% mortality in patients without conversion (p<0.01). Secondary conversion was associated with a perioperative mortality of 27%, and when performed for rupture 50%.

CONCLUSION

both primary conversion and secondary conversion for rupture carry a high operative mortality. Awareness of the risk factors may reduce conversion rate as well as early and medium term mortality.

Predictive factors for early success of endovascular abdominal aortic aneurysm repair

To identify predictive factors for postoperative success and potential predictors for satisfactory outcome of endovascular grafting for abdominal aortic aneurysm (AAA), we collected data from our prospective database, which includes a series of consecutive patients undergoing endovascular repair at the Vascular Surgery Unit, Policlinico Monteluce, Perugia, Italy. From April 1997 to July 1998, 202 patients were referred to our Unit for elective AAA repair; 94 patients (47%) were selected for endografting. Placement of the graft using endovascular technique without conversion to open laparotomy, in addition to no mortality, major morbidity, or endoleak at 30-day follow-up, was defined as postoperative success. The influence of anatomical features on postoperative results was analyzed by univariate and multivariate analysis. Our experience shows that endoluminal repair of AAA is safe and effective in the short term and male patients with small aneurysms are optimal candidates for successful repair.

The value of intraoperative intravascular ultrasound for determining stent graft size (excluding abdominal aortic aneurysm) with a modular system

Since the introduction of endovascular stent grafts at our institution we have used intraoperative intravascular ultrasound (IVUS) to definitively determine stent graft size. In this study, expected stent graft size, based on preoperative helical CT scan measurements, was compared with the actual final size, based on intraoperative IVUS measurements. Between December 1996 and January 1998, 54 patients were treated with an AneuRxTM bifurcated stent graft. Preoperatively all patients underwent angiography and helical CT scanning. Expected stent graft size was determined according to these measurements. The final stent graft size was based on IVUS measurements acquired during the procedure. Differences in expected and final size were compared and follow-up endoleaks were also noted. Differences in diameter measurements between CT and IVUS were compared using the paired Student's t-test. Differences in expected and chosen stent graft length were compared using the McNemar's test for paired proportions of binomial outcomes. Our results showed that helical CT scanning overestimates diameter and underestimates length. This underestimation of length is explained by the tortuosity of the aorta and iliac arteries while using axial slices of the CT scan. The last-minute corrections based on the intraoperative IVUS measurements did not result in a high incidence of endoleaks at fixation zones. In our opinion, the possibility of making final corrections in the choice of diameter or length of the stent graft is the additional value of intraoperative IVUS.

Can preoperative spiral CT scans alone determine the feasibility of endovascular AAA repair? A comparison to angiographic measurements

PURPOSE

To determine whether computed tomography (CT) alone can be used for excluding patients from endovascular repair for abdominal aortic aneurysms (AAA).

METHODS

Among 71 patients evaluated for endovascular AAA repair using spiral CT imaging and angiography, 31 were selected who had both studies performed within 6 months of each other using a graduated measuring catheter or guidewire. Measurements of aneurysm neck diameter, neck length, and infrarenal aortic length were made from the CT and angiographic images using handheld calipers with calibration markers as guides. Infrarenal aortic length and neck length were determined from CT images by multiplying the width of the cuts by the number of slices between the lowest renal artery and the aortic bifurcation or the top of the aneurysm, respectively.

RESULTS

CT neck diameter measurements differed significantly from the angiographic dimensions (6.3 +/- 5.1-mm mean difference, p < 0.001). In the majority of patients (25, 81%), CT neck diameters were larger (mean 7.3 +/- 3.8 mm). The mean difference in neck length measurements was 0.5 +/- 15.9 mm (p = NS). Twenty-two (71%) patients had aortic length measurements that were longer on the angiogram (mean 15.4 +/- 17.2 mm, p = NS). Five patients who would have been excluded as candidates based on overestimated CT neck diameter measurements subsequently underwent successful endovascular aneurysm repair.

CONCLUSIONS

Considerable discrepancies exist between preoperative neck diameter and infrarenal aortic length measurements obtained from CT scans and angiograms used to evaluate candidates for endovascular aortic aneurysm repair. CT alone may not be adequate for predicting the feasibility of endovascular AAA repair.

Endograft planning without preoperative arteriography: a clinical feasibility study

PURPOSE

To investigate an alternative method of preprocedural planning for aortic endografting based solely on spiral computed tomography (CT) with 3-dimensional (3D) reconstruction without preoperative arteriography.

METHODS

From August 1997 to April 1998, 25 consecutive patients with abdominal aortic aneurysms (AAA) were evaluated for endovascular repair by spiral CT scans (2-mm slice thickness) and computerized 3D model construction. No additional imaging for planning was performed. The aortoiliac dimensions, thrombus load, calcification, and vessel tortuosity were measured and evaluated from the 3D model of the aortoiliac segment. These data were used for selecting the patients; the configuration, diameter, and length of the endograft; and the attachment sites for deployment.

RESULTS

Primary procedural success was 92% (23/25). All endografts were deployed as planned, and there were no conversions to open repair. Six patients required adjunctive procedures for delivery system access or for iliac aneurysm exclusion, as predicted by the 3D model. Mean procedural time was 91 minutes (range 24 to 273). Two (8%) type II (side branch) endoleaks both sealed spontaneously within 1 month. No graft-related complications or death occurred, for a 30-day technical success rate of 100%.

CONCLUSIONS

This computerized 3D model provided accurate data for preoperative evaluation of the aortoiliac segment for endovascular AAA repair. Satisfactory technical outcomes for aortic endografts can be achieved without the use of preprocedural invasive imaging.

Endovascular repair of abdominal aortic aneurysms: where do we stand?

Endovascular repair of abdominal aortic aneurysms has evolved dramatically within the past few years. In light of the potential to reduce morbidity and mortality associated with open surgical repair, endoluminal grafting offers therapeutic options to patients who are not surgical candidates because of comorbidities. With the development of bifurcated devices, more complex aneurysms may be treated by endovascular grafting. Although successful placement of endovascular grafts requires a pronounced learning curve, including appropriate patient selection, midterm results seem consistent with those of traditional open repair of aneurysms. This review describes the current indications, minimal requirements, different devices and associated techniques, and potential complications of endoluminal repair of abdominal aortic aneurysms. Future aspects of endoluminal grafting are also discussed.

Endovascular abdominal aortic aneurysm repair with percutaneous transfemoral prostheses deployment under local anaesthesia. Initial experience with a new, simple-to-use tubular and bifurcated device in the first 27 cases

BACKGROUND

Modification of endografts are required to simplify and improve the safety of the endovascular management of abdominal aortic aneurysms (AAA).

OBJECTIVES

The aim of this study is to evaluate the efficacy of a new custom-made, tubular and bifurcated device.

MATERIALS AND METHODS

The graft consisted of a continuous, self-expanding, stainless steel, Z-stent structure, covered with a thin wall PTFE tube. Bifurcated grafts were constructed in vivo from three PTFE tubes with a continuous Z-stent structure. Twenty-seven high risk patients with a mean age of 74 (62-86) years and AAA, mean diameter 5.9 cm, were treated in the last 26 months. Tube grafts were deployed in 13 aortic and one iliac cases, bifurcated grafts in nine cases and aorto-uni-iliac grafts with femorofemoral bypass in four cases. Grafts were deployed percutaneously under local anaesthesia. Patients were followed with contrast CT periodically.

RESULTS

All grafts were deployed. There were no open conversions or other major complications. There were nine proximal and one distal postoperative endoleak. Four sealed spontaneously, three were treated successfully with endovascular techniques and three are under surveillance. In the 7 (2-23) months follow-up, one patient died due to heart failure 3 months post-procedure.

CONCLUSIONS

Local anaesthesia and percutaneous graft introduction simplify and improve the efficacy of the procedure. Continuous aortic graft support provides stability and reduces the risk of migration. PTFE is a flexible, low-profile material for use in endovascular stent-grafts. The bifurcation concept used offers a simple technique for bifurcated grafts.

Shortening of endografts during deployment in endovascular AAA repair

PURPOSE

To evaluate the incidence and extent of length changes during implantation of endovascular grafts in a prospective study of patients undergoing endovascular abdominal aortic aneurysm (AAA) repair.

METHODS

Data regarding the occurrence of intraoperative technical difficulties and device complications were recorded prospectively for the Vanguard or AneuRx self-expanding, bifurcated endovascular grafts in 64 patients (56 males; mean age 75 years). Graft length was measured in the sheath system before deployment and again immediately after deployment by fluoroscopic comparison to a graduated marking catheter.

RESULTS

Graft shortening > or = 15 mm was documented in 22 (56%) of 39 Vanguard cases and 11 (44%) of 25 AneuRx endografts. Additional extension grafts were required to correct endoleak caused by inadequate graft length in 9 (14%) patients, but no conversion to open repair was necessary.

CONCLUSIONS

There appears to be a high incidence of intraprocedural graft shortening with 2 current designs of self-expanding endoluminal grafts.

Phantom for calibration of preoperative imaging modalities in endoluminal stent-graft repair of aortic aneurysms

PURPOSE

Successful deployment of an endoluminal prosthesis for repair of an abdominal aortic aneurysm (AAA) is critically dependent on accurate preoperative assessment of aneurysm morphology with use of such modalities as contrast aortography (CA), spiral computed tomography (CT), magnetic resonance (MR) imaging, and intravascular ultrasonography (IVUWS). The authors describe a new phantom that could be used both to calibrate these four imaging modalities and to determine which imaging technique(s) is (are) best for preoperative AAA sizing.

MATERIALS AND METHODS

A life-sized AAA model was constructed of silicone elastomers with luminal access ports for introduction of contrast media and catheters. Contrast material-filled rings were positioned circumferentially along the length of the model as reference points for dimension measurements. The modalities were compared to each other relative to the actual dimensions of the model, as determined at its construction.

RESULTS

In this pilot study, all modalities were relatively similar in their ability to measure the dimensions of the AAA model. Length measurements accounted for most of the interinstitutional and interobserver variability. MR imaging had the least variability.

CONCLUSIONS

The authors developed a new phantom that can be imaged successfully with CA, CT, MR imaging, and IVUS in repetitive, reproducible fashion. Structural refinements and future larger scale, statistically significant evaluations of such models should establish this as a useful adjunct in multicenter endoluminal stent-graft trials to allow calibration of imaging modalities and to determine which modality or modalities is (are) best for preoperative AAA sizing.

Persistent collateral perfusion of abdominal aortic aneurysm after endovascular repair does not lead to progressive change in aneurysm diameter

PURPOSE

To differentiate between the phenomenon of collateral perfusion from a side branch versus graft-related endoleaks after endovascular repair of abdominal aortic aneurysms (AAA), with respect to aneurysm size and prognosis.

METHODS

We successfully treated 64 AAA patients with endovascular grafting. We followed all the patients postoperatively with spiral computed tomography at one, three, six and 12 months, and biannually thereafter. We measured aneurysm diameters preoperatively and postoperatively. We calculated preoperatively the relation of maximum aortic diameter (D) to the thrombus-free lumen diameter (L) expressed as an L/D ratio. Median follow-up was 15 months.

RESULTS

Sixteen patients had collateral perfusion during follow-up. We successfully treated two patients with embolization. One patient showed resolution of collateral perfusion after we stopped warfarin treatment. Two patients died of unrelated causes during follow-up. One patient was converted to surgical treatment, and two patients showed spontaneous resolution of their collateral perfusion. The group of patients with perfusion showed no statistically significant change of their aortic diameter on follow-up. The group of patients without perfusion showed a median decrease in aortic diameter of 8mm (p < 0.0001) at 18 months postoperatively. The group of patients with perfusion had significantly less thrombus in their aneurysm sac preoperatively than the group without perfusion, as expressed by the L/D ratio (mean L/D 0,61 versus 0,78, respectively; p=0.0021.)

CONCLUSION

There was no significant increase in aortic diameter on an average 18 months postoperatively despite persistent collateral perfusion. This may indicate a halted disease progression in the short term. Embolization of collateral vessels is associated with risk of paraplegia. We recommend a conservative approach with close observation if aneurysm diameter is stable.

Importance of graft configuration in outcome of endoluminal aortic aneurysm repair: a 5-year analysis by the life table method

AIM

The aim of this study was to determine the influence of graft configuration on the outcome of endoluminal repair of abdominal aortic aneurysm (AAA).

METHODS

The 5-year study period extended from May 1992 to May 1997 and included analysis of patients undergoing endoluminal AAA repair in the first 4.5-year period with a minimum follow-up period of 6 months. Between May 1992 and November 1996 136 patients underwent endoluminal AAA repair. Two patients who had endoluminal repair of anastomotic AAA and six patients who had secondary endoluminal repair of AAA were excluded, leaving 128 patients in the study group. There were 117 males and 11 females with a mean age for the group of 71 years. The configuration of the grafts was tubular aortic (T) (n = 50), tapered aortoiliac/femoral (AI) (n = 24) and bifurcated (B) (n = 54). Patient characteristics and co-morbidities were similar in the three groups. The procedures were performed in the operating room under radiographic control. Follow-up was complete and consisted of regular physical examination and contrast enhanced computed tomography. Outcome measures were perioperative mortality rate, need for conversion to open repair, presence of early and late endoleaks, successful exclusion of AAA from the circulation, and survival. Data were analysed by the life table method.

RESULTS

There was no significant difference in perioperative mortality for T (4%), AI (4%) and B (5.5%) configuration of endograft. Outcome for T, AI, and B configurations was respectively: primary conversion (%) 8, 12, 13; early endoleaks (n =) 5, 0, 1; late endoleaks (n =) 7, 0, 1. The overall incidence of failed procedures throughout the study period was higher in tube grafts compared with non-tube (aortoiliac and bifurcated) grafts (p < 0.05). Kaplan-Meier curves demonstrated a success probability at 40 months of 50% for tube grafts and 80% for non-tube grafts. However, a comparison of the time to procedure failure between tube versus non-tube after adjusting for competing risks (death without prior graft failure) was non-significant (p = 0.14).

CONCLUSIONS

The poor mid-term outcome for tube prostheses requires a reassessment of the criteria for selecting this configuration. It would be unwise to abandon the use of tube prostheses entirely in endoluminal repair. With increasing information on mid and long-term outcome of endoluminal AAA repair it is likely that there will be an increasing acceptance of treating smaller AAA while they are still suitable for treatment by the endoluminal method and most likely with tube grafts. A tightening of the criteria for using tube prostheses would seem sensible. In particular, the minimum length of distal neck required for endoluminal tube graft repair should be increased to the 2-2.5 cm range.

Endoleak after endovascular graft repair of experimental aortic aneurysms: does coil embolization with angiographic "seal" lower intraaneurysmal pressure?

PURPOSE

To investigate the relation between endoleaks and intraaneurysmal pressure (IAP) and the effect of coil embolization in the management of endoleaks.

METHODS

The infrarenal aorta of a dog (n = 15) was replaced by a polytetrafluoroethylene aneurysm containing a pressure transducer. Group I (n = 4) had untreated aneurysms. Group II (n = 4) had endovascularly excluded aneurysms without an endoleak. Group III (n = 7) had aneurysms excluded by means of grafts with a defect that represented the source of an endoleak. After 4 weeks of follow-up study, the endoleaks in group III dogs were subjected to coil embolization. Systolic IAP was measured daily and expressed as a ratio of systolic blood pressure obtained from a forelimb cuff. Arteriography, duplex ultrasonography, and spiral contrast computed tomography were performed to evaluate endoleaks.

RESULTS

In group I, the LAP remained close to systolic blood pressure (ratio of 0.96 +/- 0.06), whereas in group II the IAP ratio showed a decline to 0.34 +/- 0.16 (p = 0.0009 group I versus II). After an initial decrease, the IAP ratio in group III stabilized at 0.75 +/- 0.18 (p = 0.003, group II versus III). Aneurysms with an endoleak remained pulsatile with a pulse pressure of 30 +/- 16 mm Hg, which was less than that of untreated aneurysms (62 +/- 15 mm Hg; p < 0.0001 group I versus III). Arteriography and computed tomography revealed "sealing" of endoleaks after coil embolization, but IAP ratio did not decrease (0.76 +/- 0.14) after coil embolization.

CONCLUSIONS

Incomplete endovascular aneurysm exclusion caused by an endoleak fails to reduce IAP ratio and may subject the aneurysm to a continued risk for rupture. Although coil embolization resulted in angiographic and computed tomographic sealing, it failed to reduce IAP ratio.

Endovascular treatment of infrarenal abdominal aneurysms by the Stentor system: preliminary results of 79 cases. Stentor Retrospective Study Group

PURPOSE

We report the initial French multicenter experience with the Stentor system in the endovascular treatment of AAAs.

METHODS

Between May 1994 and March 1996, 79 patients with AAAs were consecutively treated with an endovascular technique using the Stentor system. There were 71 bifurcated grafts and eight straight grafts. The patients were followed-up from 1 to 18 months (mean, 5.7 months). Patient data and events were retrospectively analyzed.

RESULTS

No patients was lost to follow-up. There were no surgical conversions. Four patients died after operation (4.8%). Two of them had been considered inoperable by the standard technique. Four patients (4.8%) had pulmonary complications, and three had colonic ischemia (3.7%). Forty-five patients (57%) had postoperative fever, and a transitory thrombocytopenia (10%) developed in eight patients. In 66 patients (83%) the aneurysm was immediately excluded. The exclusion was definitive in 62 (78%). In 17 patients, there were 13 initial and six delayed endoleaks. In two of these patients, the initial endoleak sealed temporarily and resumed after 1 year of follow-up, requiring an additional straight, covered stent. Over all, seven of the leaks were treated successfully by an additional endovascular graft, one leak required a lumbar artery embolization, eight leaks sealed spontaneously, and one leak was untreated. During follow-up, there was no aneurysm rupture. Two patients died of unrelated causes.

CONCLUSION

The Stentor system can safely and effectively exclude AAAs in the short term. Careful follow-up is required to detect any delayed endoleak, and long-term results are awaited to confirm the efficacy of the method in preventing AAA rupture.

Morphologic assessment of abdominal aortic aneurysms by spiral computed tomographic scanning

PURPOSE

The aim of this study was to seek a relationship between the morphologic features of abdominal aortic aneurysms and the feasibility of endoaortic grafting.

METHODS

Between June 1995 and January 1996, 86 patients were prospectively studied with contrast-enhanced spiral computed tomographic scans, which provided 35 parameters concerning the aorta and iliac arteries. Four groups were established according to the diameter of abdominal aortic aneurysms: group A, 40 to 49 mm, 36 patients; group B, 50 to 59 mm, 26 patients; group C, 60 to 69 mm, 10 patients; and group D, greater than 70 mm, 14 patients.

RESULTS

There was a correlation between the diameter and length of the aneurysm (p < 0.0001) and between aneurysm diameter and length of the proximal neck (p < 0.001). Presence of a proximal neck or a distal neck was more frequent in groups A and B than in groups C and D (p < 0.01). The feasibility of endovascular grafting was estimated at between 50% and 61.6% and was higher in groups A and B than in groups C and D (p < 0.01).

CONCLUSIONS

This study has shown an inverse relationship between the diameter of the aneurysm and the length of the aortic neck (correlation coefficient, -0.3640, p < 0.001). The diameter of an aneurysm was the most useful of the 31 parameters measured in predicting the feasibility of endoaortic grafting, estimated at 71% for aneurysms less than 60 mm in diameter and 37.5% for aneurysms greater than 60 mm in diameter (p < 0.01).

Endoluminal repair of abdominal aortic aneurysms: strengths and weaknesses of various prostheses observed in a 4.5-year experience

PURPOSE

To summarize the results of endovascular abdominal aortic aneurysm (AAA) treatment using several endograft designs over a 4.5-year experience and offer comparisons on the various devices.

METHODS

From May 1992 to August 1996, 121 AAA patients meeting the criteria for an endoluminal repair were treated with 1 of 5 endograft designs in three configurations. The endografts were implanted in the operating room under fluoroscopic control. Follow-up included contrast-enhanced computed tomography within 10 days of operation, 6 months postoperatively, and annually thereafter.

RESULTS

Endografts were successfully deployed in 106 patients (88%). Fifteen cases were converted to open repair. Six procedure-related deaths occurred within 30 days owing to myocardial infarction (3), combined renal failure and septicemia (2), and multisystem failure (1). There were 36 local/vascular complications (30%) and 18 systemic/remote complications (15%). Of the 121 patients undergoing endoluminal AAA repair, 93 (77%) are currently alive and well with their AAAs excluded from the circulation.

CONCLUSIONS

Trends in endoluminal AAA repair and prosthetic design point toward simpler devices and earlier treatment of smaller aneurysms once the long-term outcome of aortic endografting has been determined.

Historic control comparison of outcome for matched groups of patients undergoing endoluminal versus open repair of abdominal aortic aneurysms

PURPOSE

Currently no randomized studies show the relative morbidity and mortality of the open and endoluminal methods of abdominal aortic aneurysm (AAA) repair. The aim of this study was to analyze the outcome of two matched groups of patients with AAA, one undergoing open repair and the other undergoing endoluminal repair.

METHODS

Two groups of patients who had undergone repair of AAA by open technique (group 1) or by endoluminal methods (group 2) were compared. A historic control cohort of 27 patients was selected from 56 consecutive patients who underwent open repair of AAA between January 1991 and February 1992. Patients considered unsuitable for the endoluminal method on the basis of computed tomography and aortography were excluded (n=29). Between May 1992 and November 1994 prospective data were recorded for 62 consecutive patients who underwent endoluminal repair by tube or bifurcated endografts. Twenty-eight patients who had been specifically referred for endoluminal AAA repairs because of preexisting severe medical comorbidities were excluded. Six of the endoluminal cases had failure, requiring conversion to open operation, and were excluded for separate analysis, leaving 28 patients in group 2. Patients in both groups were thus fit and suitable for either open or endoluminal repair and were comparable in relation to age, sex, risk factors, dimensions, and form of AAA.

RESULTS

The mean values for operation time, blood loss, intensive care stay, and hospital stay for group 1 and group 2 were 2.6 versus 3.1 hours, 1422 versus 873 ml,* 1.8 versus 0.7 days,* and 12.4 versus 11.1 days, respectively (*p<0.05). Local/vascular complications occurred in 15% of patients in group 1 compared with 25% in group 2 (p=0.55), whereas remote/systemic complications occurred in 37% and 29%, respectively (p=0.3). Five of 28 patients in the endoluminal group had complications requiring early operative repair (n=3) or late revision (n=2). When comparison was made on an intention-to-treat basis (with failed procedures included), the incidence of local/vascular complications was significantly greater for endoluminal repair (p=0.047).

CONCLUSIONS

The incidence of systemic/remote complications was similar for the two groups in spite of significantly less blood loss and shorter intensive care unit stay with endoluminal repair. The incidence of local/vascular complications had a tendency to be higher for endoluminal compared with standard open method (and was significantly greater if failed procedures were included). In this early experience with prototype devices, patients who were medically suitable for open surgical procedures did not derive benefit from the less invasive endoluminal technique with respect to duration of operation, length of hospital stay, or perioperative morbidity and mortality. On the other hand, because they also did not have worse outcome, a randomized study is now justified in this group.

Endoluminal repair of atypical dissecting aneurysm of descending thoracic aorta and fusiform aneurysm of the abdominal aorta

A 62-year-old male patient was admitted with acute dissociation of the descending thoracic aorta and an infrarenal abdominal aortic aneurysm (AAA). Investigation revealed that the thoracic dissection probably had arisen retrogradely in the posterior wall of the AAA and extended superiorly to the left subclavian artery as a blind sac. Implantation of an endoluminal graft device below the renal arteries enabled simultaneous treatment of the AAA and the thoracic aortic dissection. The patient had an uncomplicated recovery. Postoperative aortography and computed tomography demonstrated normal flow through the aorta and endograft without leak of contrast into the AAA sac or the false lumen of the dissection. Contrast computed tomography 6 months after operation demonstrated that the false lumen was no longer evident.

Surgical management of complications following endoluminal grafting of abdominal aortic aneurysms

OBJECTIVE

The aim of this study was to report the outcome of endoluminal grafting of abdominal aortic aneurysms (AAA) with special reference to complications.

METHODS

Between May 1992 and August 1994 endoluminal repair of aneurysms was undertaken in 61 patients. In 53 the aneurysm was aortic and these are the basis of this report. In patients with AAA all procedures were elective and were performed in the operating room with the patient draped for an open repair in the event of failed endoluminal repair. The configuration of the endografts was tubular 36, tapered aortoiliac/aortofemoral 12 and bifurcated 5. Radiographic guidance was used to pass the endografts into the aorta via a delivery sheath introduced through the femoral or iliac arteries.

RESULTS

Successful endoluminal repair of AAA was achieved in 43 of 53(81%) patients. In the remaining 10 patients, endoluminal repair was abandoned in favour of an open repair. There were 17(32%) local/vascular and 13(25%) systemic/remote remote complications. The sum of these complications occurring in successful endoluminal repairs and those complications leading to failure of endoluminal repair was 40(75%). There were two cardiac deaths within 30 days in patients undergoing endoluminal repair (both procedure related) and four late deaths (unrelated to aneurysm repair). Three of the late deaths were in patients undergoing endoluminal repair and one endoluminal converted to open repair.

CONCLUSION

Endoluminal repair of AAA in our experience has a low perioperative (< 30 days) mortality rate (3.7%) but a high morbidity rate (75%). It is recommended that complications be classified into three groups: systemic/remote and local/vascular (following successful endoluminal repair) plus those complications leading to failure of endoluminal repair. The first group is composed of medical complications while the latter two groups comprise those surgical complications directly related to the endoluminal technique.