Two-year outcomes after conventional or endovascular repair of abdominal aortic aneurysms

Aneurysmen und Dissektionen der thorakalen und abdominellen Aorta

One to four per cent of all deaths in patients over 65 are caused by aneurysmatic diseases of the abdominal or thoracic aorta. For elective surgery in abdominal aneurysms, open surgery and endovascular treatment both demonstrate brilliant overall results. In the thoracic aorta, new endovascular procedures have led to considerable reductions of postoperative morbidity and mortality. Nevertheless, in view of the endovascular procedure's high cost and the still unclear long-term behaviour of the stent device, a second opinion from a specialised centre is an absolute necessity.

[Abdominal aortic aneurysm and renovascular disease]

Recent technological advances in the diagnosis and therapy of abdominal aortic aneurysm and renovascular disease are continuing to bring about changes in the way patients suffering from these conditions are treated. The prevalence of both these conditions is increasing. This is due to greater life-expectancy in patients with arteriosclerosis, a pathogenetic factor underlying both conditions. The application of diagnostic imaging techniques to non-vascular conditions has led to the early diagnosis of abdominal aortic aneurysm. Clinical suspicion of reno-vascular disease can be confirmed easily using high-resolution diagnostic imaging modalities such as CT angiography and magnetic resonance angiography. Endovascular intervention is successfully replacing conventional surgical repair techniques, with the result that it may be possible to improve outcome in both conditions using effective and minimally invasive approaches. Future technological developments will enable these endovascular techniques to be applied in the large majority of patients with abdominal aortic aneurysm or renovascular disease.

The Current Status of AAA Stent Grafting

It is now 16 years since the endovascular treatment of abdominal aortic aneurysm (AAA) was first described. It is probably true to say that, with current device technology, > 50% of all patients with an infrarenal aneurysm can be treated with an endograft. Endografting has become an important tool in the treatment of AAA. There are many reasons for this success. Rapid technical development followed the initial "homemade" devices, allowing easy accurate insertion. In early cohort series it was always the case that the operative mortality of endografting in AAA was lower than surgical treatment. In addition, postoperative management was easier and hospital stay was shorter after an endograft. No evidence indicated that quality of life improved after the perioperative period, however, and it was unclear whether the reduction in intensive hospital care requirement justified the considerable extra costs for an endovascular device. Despite these shortcomings, early widespread public awareness pushed endograft treatment forward. Patients started to ask for this new treatment option. But long-term outcome data then, and to some extent today, are still lacking.

Patient fitness and survival after abdominal aortic aneurysm repair in patients from the UK EVAR trials

Background

The aim was to use a validated fitness score to determine whether fitter patients with a large abdominal aortic aneurysm (AAA) benefited from having open rather than endovascular repair.

Methods

The Customized Probability Index (CPI) was applied to patients in the Endovascular Aneurysm Repair (EVAR) I and II trials. Interaction tests between CPI and randomized group assessed the effect of fitness and type of AAA repair on elective 30-day mortality and 4-year survival.

Results

The mean(s.d.) CPI scores were 3·6(9·3) for 1252 EVAR I patients and 10·0(11·3) for 404 EVAR II patients (range − 25 to + 43) (P < 0·001). The fitness of EVAR I patients was classified as good (579 patients, mean CPI − 4·2), moderate (331 patients, mean CPI 5·7) or poor (338 patients, mean CPI 15·1). Only in the good fitness group did 30-day mortality convincingly favour endovascular repair (odds ratio 0·24, P = 0·030), but overall the test of interaction was not significant (P = 0·363). For 4-year all-cause and aneurysm-related mortality, there was no benefit for either treatment across all fitness scores (P = 0·281 and P = 0·371 respectively).

Conclusion

The benefit of endovascular repair was most convincing in the fittest patients. There was no evidence that the fittest patients benefited more from open surgery.

Final 12-year follow-up of Surgery versus Surveillance in the UK Small Aneurysm Trial

Background

The aim was to determine whether early open surgical repair would benefit patients with small abdominal aortic aneurysm compared with surveillance on long-term follow-up.

Methods

The 1090 patients who were enrolled into the UK Small Aneurysm Trial between 1991 and 1995 were followed up for aneurysm repair and mortality until November 2005.

Results

By November 2005, 714 patients (65·5 per cent) had died, 929 (85·2 per cent) had undergone aneurysm repair, 150 (13·8 per cent) had died without aneurysm repair and 11 (1·0 per cent) remained alive without aneurysm repair. After 12 years, mortality in the surgery and surveillance groups was 63·9 and 67·3 per cent respectively, unadjusted hazard ratio 0·90 (P = 0·139). Three-quarters of the surveillance group eventually had aneurysm repair, with a 30-day elective mortality of 6·3 per cent (versus 5·0 per cent in the early surgery group, P = 0·366). Estimates suggested that the cost of treatment was 17 per cent higher in the early surgery group, with a mean difference of £1326. The death rate in these patients was about twice that in the population matched for age and sex.

Conclusion

There was no long-term survival benefit of early elective open repair of small abdominal aortic aneurysms. Even after successful aneurysm repair, the mortality among these patients was higher than in the general population.

Five-year report of a multicenter controlled clinical trial of open versus endovascular treatment of abdominal aortic aneurysms

OBJECTIVE

Compare long-term results of endovascular treatment and standard open repair of abdominal aortic aneurysms in a multicenter, concurrent-controlled trial.

METHODS

334 subjects were treated with standard open repair (control, n = 99) or the original EXCLUDER Bifurcated Endoprosthesis (test, n = 235). Five-year clinical evaluations and corelab radiographic results are analyzed.

RESULTS

Overall and aneurysm-related survival are similar. There have been ten open conversions, most frequently for enlarging sacs without endoleak. Two patients died after conversion. Including reinterventions and complications of reinterventions as adverse events, there is significant, persistent long-term reduction in major adverse events. At 5 years, corelab reported 0% limb narrowing, 0% trunk migration, 0% component (contralateral leg, aortic extender, and iliac extender) migration, 0% fracture, endoleak in 3% (2 type II/68), and aneurysm growth (>5 mm compared to baseline) in 38% (30/78) of the test group. There are no aneurysm ruptures in either test or control group.

CONCLUSIONS

After 5 years follow-up, endovascular repair is a safer and effective treatment compared with open surgical repair for abdominal aortic aneurysms. Major adverse events are less frequent with the endograft despite the need for late reinterventions. Aneurysm expansion is observed in nearly two-fifths of patients but is not associated with endoleak or aneurysm rupture. Multicenter clinical trials are evaluating a newer version of this device designed to avoid this high rate of sac expansion.

Myocardial Damage in High-risk Patients Undergoing Elective Endovascular or Open Infrarenal Abdominal Aortic Aneurysm Repair

OBJECTIVE

Dobutamine stress echocardiography (DSE) provides an objective assessment of the presence and extent of coronary artery disease. Therefore we compared cardiac outcome in patients at high-cardiac risk undergoing open or endovascular repair of infrarenal AAA using preoperative DSE results.

METHODS

Consecutive patients with >or=3 cardiac risk factors (age >70 years, angina pectoris, myocardial infarction, heart failure, stroke, renal failure, and diabetes mellitus) undergoing infrarenal AAA repair were reviewed retrospectively. All underwent cardiac stress testing using DSE. Postoperatively data on troponin release and ECG were collected on day 1, 3, 7, before discharge, and on day 30. The main outcome measures were perioperative myocardial damage and myocardial infarction or cardiovascular death.

RESULTS

All 77 patients (39 endovascular, 38 open) had a history of cardiac disease. The number and type of cardiac risk factors were similar in both groups. Also DSE results were similar: 55 vs 56%, 24 vs 28%, and 21 vs 18% had no, limited, or extensive stress induced myocardial ischemia respectively. The incidence of perioperative myocardial damage (47% vs 13%, p=0.001) and the combination of myocardial infarction or cardiovascular death (13% vs 0%, p=0.02) was significantly lower in patients receiving endovascular repair.

CONCLUSION

In patients with similar high cardiac risk, endovascular repair of infrarenal aortic aneurysms is associated with a reduced incidence of perioperative myocardial damage.

Abdominal aortic aneurysm neck remodeling after open aneurysm repair

PURPOSE

Proximal endovascular aortic graft fixation and maintenance of hemostatic seal depends on the long-term stability of the aortic neck. Previous investigations of aortic neck dilation mostly focused on the infrarenal aortic diameter. Fenestrated and branched stent grafts facilitate suprarenal graft fixation and may thereby improve the long-term integrity of the aortic attachment site. For these devices, the natural history of the suprarenal aortic segment is also of interest. We investigated the natural history of the supra- and infrarenal aortic segment after open abdominal aortic aneurysm (AAA) repair.

METHODS

For this retrospective analysis, we reviewed the preoperative and the initial postoperative as well as the most recent CT series that were obtained from 52 patients undergoing conventional repair of an infrarenal abdominal aortic aneurysm between January 1998 and December 2002. Measurements were performed using electronic calipers on a "split screen", allowing direct comparison of subsequent CT series at corresponding levels along the vessel. Main outcome measures were changes in postoperative measures of the supra- and infrarenal aortic diameters.

RESULTS

The first postoperative exam was at a mean (+/-SD) of 7.0 +/- 3.5 months, and the final exams were at 44.4 +/- 21 months. Over this time period, the estimated rate of change in suprarenal diameter was 0.18 mm/ y with 95% confidence interval (CI) from 0.08 to 0.27. The estimated rate of change for the infrarenal diameter was 0.16 (95% CI: 0.05 to 0.27). A clinically relevant diameter increase of >or=3 mm was observed in seven patients (13%). There was evidence of larger diameter increases associated with larger AAA diameters (P = .003 and <.001 for suprarenal and infrarenal diameters), an inverted funnel shape (P = .002 and <.001), and marginal evidence of association with a history of inguinal hernia (P = .043 and .066).

CONCLUSIONS

Although there is statistically significant evidence of increases in the supra- and infrarenal aortic diameters after conventional AAA repair, mean annual increases tended to be small and clinically relevant increases of 3 mm or more were observed in only a small proportion of cases.

Surgery Insight: advances in endovascular repair of abdominal aortic aneurysms

Despite improvements in diagnostic and therapeutic methods and an increased awareness of their clinical significance, abdominal aortic aneurysms (AAAs) continue to be a major source of morbidity and mortality. Endovascular repair of AAAs, initially described in 1990, offers a less-invasive alternative to conventional open repair. The technology and devices used for endovascular repair of AAAs have progressed rapidly and the approach has proven to be safe and effective in short to midterm investigations. Furthermore, several large trials have demonstrated that elective endovascular repair is associated with lower perioperative morbidity and mortality than open repair. The long-term benefits of endovascular repair relative to open repair, however, continue to be studied. In addition to elective repair, the use of endovascular repair for ruptured AAAs has been increasing, and has been shown to be associated with reduced perioperative morbidity and mortality. Advances in endovascular repair of AAAs, including the development of branched and fenestrated grafts and the use of implantable devices to measure aneurysm-sac pressures following stent-graft deployment, have further broadened the application of the technique and have enhanced postoperative monitoring. Despite these advances, endovascular repair of AAAs remains a relatively novel technique, and further long-term data need to be collected.

Endovascular abdominal aortic aneurysm repair

The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique.

Results of streamlined regional ambulance transport and subsequent treatment of acute abdominal aortic aneurysms

OBJECTIVE

To describe the triage of patients operated for non-ruptured and ruptured abdominal aortic aneurysms (AAAs) before the endovascular era.

DESIGN

Retrospective single-centre cohort study.

METHODS

All patients treated for an acute AAA between 1998 and 2001 and admitted to our hospital were evaluated in the emergency department for urgent AAA surgery. All time intervals, from the telephone call from the patient to the ambulance department, to the arrival of the patient in the operating theatre, were analysed. Intraoperative, hospital and 1-year survival were determined.

RESULTS

160 patients with an acute AAA were transported to our hospital. Mean (SD) age was 71 (8) years, and 138 (86%) were men. 34 (21%) of these patients had symptomatic, non-ruptured AAA (sAAA) and 126 patients had ruptured AAA (rAAA). All patients with sAAA and 98% of patients with rAAA were operated upon. For the patients with rAAA, median time from telephone call to arrival at the hospital was 43 min (interquartile range 33-53 min) and median time from arrival at the hospital to arrival at the operating room was 25 min (interquartile range 11-50 min). Intraoperative mortality was 0% for sAAA and 11% for rAAA (p = 0.042), and hospital mortality was 12% and 33%, respectively (p = 0.014).

CONCLUSIONS

A multidisciplinary unified strategy resulted in a rapid throughput of patients with acute AAA. Rapid transport, diagnosis and surgery resulted in favourable hospital mortality. Despite the fact that nearly all the patients were operated upon, survival was favourable compared with published data.

Intraobserver and interobserver variability of 64-row computed tomography abdominal aortic aneurysm neck measurements

BACKGROUND

Integrity of the abdominal aortic aneurysm (AAA) neck is crucial for the long-term success of endovascular AAA repair (EVAR). However, suitable tools for reliable assessment of changes in small aortic volumes are lacking. The purpose of this study was to assess the intraobserver and interobserver variability of software-enhanced 64-row computed tomographic angiography (CTA) AAA neck volume measurements in patients after EVAR.

METHODS

A total of 25 consecutive patients successfully treated by EVAR underwent 64-row follow-up CTA in 1.5-mm collimation. Manual CTA measurements were performed twice by three blinded and independent readers in random order with at least a 4-week interval between readings. Maximum and minimum transverse aortic neck diameters were measured twice on two different levels within the proximal neck. Volumetry of the proximal aortic neck was performed by using dedicated software. Variability was calculated as 1.96 SD of the mean arithmetic difference according to Bland and Altman. Two-sided and paired t tests were used to compare measurements. P values <.05 were considered to indicate statistical significance.

RESULTS

Intraobserver agreement was excellent for dedicated aneurysmal neck volumetry, with mean differences of less than 1 mL (P > .05), whereas it was poor for transverse aortic neck diameter measurements (P < .05). However, interobserver variability was statistically significant for both neck volumetry (P < .005) and neck diameter measurements (P < .015).

CONCLUSIONS

The reliability of dedicated AAA neck volumetry by using 64-row CTA is excellent for serial measurements by individual readers, but not between different readers. Therefore, studies should be performed with aortic neck volumetry by a single experienced reader.

Improved survival after introduction of an emergency endovascular therapy protocol for ruptured abdominal aortic aneurysms

BACKGROUND

The study was conducted to demonstrate improved survival (30-day mortality) after the introduction of an emergency endovascular therapy protocol for ruptured abdominal aortic aneurysms (rAAA). Numerous authors have successfully demonstrated reduced mortality in patients with rAAA using endovascular techniques. Comparison of endovascular aneurysm repair (EVAR) with open repair for rAAA may be misleading, however, because EVAR cannot be performed on all patients, and selection bias may explain the superior performance of any given surgical or endovascular strategy. We developed a model to predict mortality in patients before the introduction of EVAR (preprotocol population), applied this model to predict 30-day mortality among prospective patients (postprotocol population), and compared observed vs expected results.

METHODS

We assessed 126 patients with rAAA. Primary outcome was 30-day mortality. Potential confounding variables were age, sex, presurgical lowest recorded systolic blood pressure (SBP), and glomerular filtration rate (GFR). A logistic regression model incorporating significant confounders was used to evaluate changes in 30-day mortality for all patients with rAAA after introduction of the EVAR protocol. Separate logistic regressions were done to compare 30-day mortality for preprotocol vs patients receiving EVAR and preprotocol vs patients receiving postprotocol open repair. Cumulative sum (CUSUM) analysis was used to assess shifts in the performance of the rAAA program over time.

RESULTS

Significant confounders were SBP, absence of SBP, and GFR. Logistic regression found evidence of lower mortality after the protocol was introduced, 17.9% vs 30.0% (odds ratio [OR], 0.385; 95% confidence interval [CI], 0.141 to 0.981; P = .046). Comparison of all open repairs (preprotocol and postprotocol) and EVAR demonstrated decreased risk for EVAR of 5.0% vs 28.3% (OR, 0.109; 95% CI, 0.013 to 0.906; P = .0084). Unstable patients (SBP <or=80) showed a trend towards improved survival with EVAR relative to open repair (14.3% vs 56.0%, P = .061). Comparison of preprotocol surgery with open repair after the introduction of the protocol found no evidence of a difference between mortality rates for the open procedures-30.0% (preprotocol) vs 25.0% (postprotocol; OR, 0.688; 95% CI, 0.335 to 1.415, P = .3031)-demonstrating that the improved performance observed with CUSUM analysis was related to the introduction of the EVAR protocol.

CONCLUSION

Our predictive model using "weighted" CUSUM analysis (a measure of performance over time) demonstrated that a predefined strategy of management of rAAA that includes EVAR is associated with improved (P < .05) mortality. Unstable patients with rAAA may be particularly benefited by EVAR and should not be excluded from repair. Appropriate patients with rAAA who are undergoing treatment in experienced vascular centers should be offered EVAR as the treatment of choice.

The outcome of endovascular repair of small abdominal aortic aneurysms

OBJECTIVE

To assess the outcome of endovascular repair (EVAR) of small abdominal aortic aneurysms (AAA, <or=5.5 mm maximum diameter) in Australia.

SUMMARY BACKGROUND DATA

Randomized trials have suggested that small AAAs should not be treated by open surgery. EVAR is associated with less perioperative mortality than open surgery for large AAAs. We assessed the outcome of EVAR of small AAAs as part of a national audit.

METHODS

ASERNIP-S carried out a prospective audit of EVAR performed between November 1999 and May 2001 in Australia. A total of 478 of the 961 patients entered underwent treatment of a small AAA. Data were collected regarding preoperative characteristics, procedural outcome, and intermediate success. Median follow-up was 3.2 years. Data were analyzed using Kaplan-Meier and Cox proportional hazard analyses.

RESULTS

The 30-day mortality and technical success rates were 1.1% and 98%, respectively. Postoperative complications occurred in 29%. Survival was 84% and 52% at 3 and 5 years, respectively. Primary, assisted primary, and secondary clinical success rates were 72%, 79%, and 82%, respectively, at 3 years. Reintervention rate was 11% at 3 years; however, 15% of patients continued to have significant aortic sac enlargement. Survival was reduced in patients considered unfit for general anesthesia (odds ratio = 2.6; 95% confidence interval, 1.4-4.8, P = 0.002) or those who had elevated preoperative serum creatinine (odds ratio = 2.0; 95% confidence interval, 1.3-3.0, P = 0.001).

CONCLUSIONS

EVAR can be carried with good perioperative outcome in patients with small AAA; however, intermediate success is hampered by the need for reintervention and continued aortic sac enlargement. At present, widespread treatment of small AAAs by EVAR would appear inappropriate.

Should usual criteria for intervention in abdominal aortic aneurysms be "downsized," considering reported risk reduction with endovascular repair?

Two randomized trials have demonstrated the safety of waiting until abdominal aortic aneurysm (AAA) diameter reaches 5.5 cm for repair in most patients. Other recent randomized trials have demonstrated lower perioperative mortality and morbidity with endovascular aneurysm repair (EVAR) compared to open surgery. Therefore, it is logical to assume that endovascular repair may change the appropriate threshold for intervention. However, endovascular repair is not as durable as open surgery and is associated with ongoing risks of rupture and reintervention. Decision analysis based on data available in 1998 showed that endovascular repair should not change the threshold for intervention. Since that time retrospective data have emerged to suggest that outcomes with endovascular repair are improved in smaller AAAs, although this may simply represent selection bias and the natural history of small AAAs. Randomized trials are appropriate to determine whether improved endovascular outcomes in small AAAs reduce late rupture and reintervention enough to justify early intervention in patients with appropriate anatomy. In the absence of data from these trials, the threshold for intervention should not be changed.

Influence of Severe Infrarenal Aortic Neck Angulation on Complications at the Proximal Neck Following Endovascular AAA Repair: A EUROSTAR Study

PURPOSE

To examine the influence of severe infrarenal neck angulation (SNA) on complications after endovascular repair of abdominal aortic aneurysm (AAA).

METHODS

From October 1996 to January 2006, 5183 patients who underwent endovascular aneurysm repair using a Talent, Zenith, or Excluder stent-graft were enrolled into the EUROSTAR registry. Incidence of proximal type I endoleak, stent-graft migration, proximal neck dilatation, aneurysm rupture, secondary interventions, and all-cause and aneurysm-related mortality were compared between patients with and without severe infrarenal neck angulation (>60 degrees angle between the infrarenal aortic neck and the longitudinal axis of the aneurysm).

RESULTS

In the short term (before discharge), proximal type I endoleak (OR 2.32, 95% CI 1.60 to 3.37, p<0.0001) and stent-graft migration (OR 2.17, 95% CI 1.20 to 3.91, p=0.0105) were observed more frequently in patients with SNA. Over the long term, higher incidences of proximal neck dilatation > or =4 mm (HR 1.26, 95% CI 1.11 to 1.43, p=0.0004), proximal type I endoleak (HR 1.80, 95% CI 1.25 to 2.58, p=0.0016), and need for secondary interventions (HR 1.29, 95% CI 1.00 to 1.67, p=0.0488) were seen in patients with SNA. All-cause mortality, aneurysm-related mortality, and rupture of the aneurysm were similar in patients with and without severe neck angulation. In the subgroup of patients with an Excluder endograft, proximal endoleak at the completion angiogram (OR 4.49, 95% CI 1.31 to 15.32, p=0.0166) and long-term proximal neck dilatation (HR 1.67, 95% CI 1.20 to 2.33, p=0.0026) were more frequently observed in patients with SNA. In the Zenith subgroup, proximal endoleak at the completion angiogram (OR 2.62, 95% CI 1.49 to 4.63, p=0.0009) and proximal stent-graft migration before discharge (OR 2.34, 95% CI 1.06 to 5.19, p=0.0353) were more common in patients with SNA. In the Talent subgroup, long-term proximal endoleak (HR 2.09, 95% CI 1.27 to 3.44, p=0.0036), proximal neck dilatation (HR 1.29, 95% CI 1.05 to 1.60, p=0.0168), and secondary interventions (HR 1.54, 95% CI 1.05 to 2.24, p=0.0259) were more frequently observed in patients with SNA.

CONCLUSION

Severe infrarenal aortic neck angulation was clearly associated with proximal type I endoleak, while the relationship with stent-graft migration was not clear. Excluder, Zenith, and Talent stent-grafts perform well in patients with severe neck angulation, with only a few differences among devices.

Elective treatment of abdominal aortic aneurysm with endovascular or open repair: The first decade

OBJECTIVES

The development of endovascular aneurysm repair (EVAR) as an alternative to open repair of abdominal aortic aneurysms (AAA) has led to an increasing number of patients being treated by this less-invasive technique. It was anticipated that EVAR would reduce the operative mortality and morbidity compared with open repair. This study examined the initial 10-year experience in one center when both techniques were available to determine if there were advantages to one technique or the other, putting the results into the perspective of routine clinical care of patients with infrarenal AAA.

METHODS

From June 1996 to May 2005, 677 patients underwent elective repair of their infrarenal AAA, of which 417 were treated with open repair and 260 by EVAR. Demographic and aneurysm-specific data, comorbidities, operative morbidity, mortality, and late outcome were analyzed.

RESULTS

Open repair patients were 2 years younger (71 vs 74 years, P < .001), had larger aneurysms (6.01 +/- 1.38 cm vs 5.45 +/- 0.99 cm, P < .001), greater familial predisposition, a higher incidence of current smokers, and a higher incidence of chronic obstructive pulmonary disease than the EVAR group. There were no differences in renal function, hypertension, coronary artery disease, or heart failure between the two groups. Overall operative mortality was 3.1%; operative mortality per group was 3.5% for open and 2.7% for EVAR (P = .627). Procedure-related outcomes showed significant differences in operative blood loss and length of hospital stay in favor of EVAR, and 95% of the EVAR patients were discharged home vs 83% in the open repair group (P < .001). A Kaplan-Meier log-rank analysis showed no difference in early or long-term survival between open repair and EVAR (P = .20), but did show a difference in mid-term (3-year) survival favoring open repair (P < .002). Survival analysis by age (<70 and > or =70 years) showed no difference between treatment groups.

CONCLUSIONS

Open repair and EVAR are both performed safely in patients treated for elective infrarenal AAA. EVAR has the perioperative advantages of reduced blood loss, reduced length of intensive care unit and hospital stay, and increased number of patients discharged to home. The mid-term survival advantage of open repair has been observed in other reports and deserves further study.

Impact of Study Design on Outcome after Endovascular Abdominal Aortic Aneurysm Repair. A Comparison between the Randomized Controlled DREAM-trial and the Observational EUROSTAR-registry

BACKGROUND

Patients with abdominal aortic aneurysm (AAA) can be treated by transfemoral endovascular intervention and by conventional open surgery. Level-one evidence of the safety and efficacy of one treatment mode over the other is only provided by a randomised controlled trial (RCT). Results reported by voluntary registries are considered less valid than data from RCTs. On the other hand the outcome of a RCT may not be generalisable to the common practice because of vigorous selection of patients and institutions.

PURPOSE

The outcomes reported by the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial were compared with the results of the EURopean collaborators on Stent-graft techniques for AAA Repair (EUROSTAR) registry.

METHODS

To obtain comparable study groups with regard to risk factors equal proportions of ASA I, II and III patients as observed in the endovascular arm of the DREAMtrial were selected at random from the EUROSTAR-registry. All patients had an aneurysm of at least 50mm. Only patients, who had been enrolled into the registry from 1999, were selected to avoid the influence of first generation endografts which are not longer in use. Patient characteristics and outcomes of endovascular AAA repair (EVAR) of EUROSTAR and DREAM-trial participants were compared. Differences in early findings between study groups were assessed by Chi-Square tests for discrete variables and by Wilcoxon rank sum tests for continuous variables. Follow-up variables were analysed by Kaplan-Meier and Cox proportional hazard models.

RESULTS

Data of 177 patients of the DREAM trial with randomization to EVAR and 856 patients selected in the EUROSTAR-registry were compared. Baseline characteristics were comparable between the EUROSTAR-cohort and EVAR-arm of the DREAM-trial. The 36-month survival-rate was 87.6% for EVAR-arm in the DREAM-trial similar to the 86.8% found in this EUROSTAR-study population. The freedom of secondary procedures reached after 3 years 85.7%, and 86.9% in the DREAM and EUROSTAR-cohort, respectively.

CONCLUSION

We found comparable characteristics and outcomes between patients of comparable risk class of the EUROSTAR-registry and the EVAR-cohort of the DREAM-trial. This demonstrates the following: first, the EUROSTAR-data provide reliable information, and further comparisons of registry data with patients treated by conventional AAA surgery may be justified. Secondly, the various outcomes of the randomised DREAM trial appear generalisable, as it agrees with observations in a broad common practice derived database.

Systematic Review and Meta-analysis of 12 Years of Endovascular Abdominal Aortic Aneurysm Repair

BACKGROUND

Endovascular repair (ER) of abdominal aortic aneurysm (AAA) is a new technique, and reported rates of endoleak, conversion to open repair, rupture and mortality vary widely. The aim of this study was to estimate these rates from the published data, and examine how this has changed as more patients have undergone ER.

METHODS

A systematic review and meta-analysis of publications identified through searches of the electronic databases EMBASE and Medline. All publications quoting endoleak, conversion to open repair, rupture and mortality rates for a series of patients undergoing ER were included.

RESULTS

163 studies pertaining to 28,862 patients undergoing ER were identified as relevant for the review and meta-analysis. The pooled estimate for operative mortality was 3.3% (95% confidence interval 2.9 to 3.6%). The pooled estimate for type 1 endoleaks was 10.5% (95% confidence interval 9.0 to 12.1%), with an annual rate of 8.4% (95% confidence interval 5.7% to 12.2%). The pooled estimate of type 2,3 and 4 endoleaks was 13.7% (95% confidence interval 12.3 to 15.3%), with an annual rate of 10.2% (95% confidence interval 7.4% to 14.1%). The pooled estimate for primary conversion to open repair was 3.8% (95% confidence interval 3.2 to 4.4%), and for secondary conversion to open repair 3.4% (95% confidence interval 2.8 to 4.2%). The pooled estimate for post-operative rupture was 1.3% (95% confidence interval 1.1 to 1.7%), with an annual rupture rate of 0.6% (95% confidence interval 0.5% to 0.8%). Multivariate meta-regression analysis showed that rates of operative mortality, post-operative rupture and total number of endoleaks all fell significantly (p<0.05) over time.

CONCLUSIONS

This study demonstrates a low mortality and a gradual reduction in vascular morbidity and mortality associated with endovascular repair since it was first introduced.

Biomechanics of abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is a condition whereby the terminal aorta permanently dilates to dangerous proportions, risking rupture. The biomechanics of AAA has been studied with great interest since aneurysm rupture is a mechanical failure of the degenerated aortic wall and is a significant cause of death in developed countries. In this review article, the importance of considering the biomechanics of AAA is discussed, and then the history and the state-of-the-art of this field is reviewed--including investigations into the biomechanical behavior of AAA tissues, modeling AAA wall stress and factors which influence it, and the potential clinical utility of these estimates in predicting AAA rupture.

Carbon dioxide digital subtraction angiography-assisted endovascular aortic aneurysm repair in the azotemic patient

OBJECTIVE

This report analyzes the safety and efficacy of carbon dioxide digital subtraction angiography (CO(2)-DSA) for EVAR in a group of patients with renal insufficiency compared with a concurrent group of patients with normal renal function undergoing EVAR with iodinated contrast angiography (ICA).

METHODS

Between 2003 and 2005, 100 consecutive patients who underwent EVAR using ICA, CO(2)-DSA, or both were retrospectively reviewed, and preoperative, intraoperative, postoperative, and follow-up variables were collected. Patients were divided into two groups depending on renal function and contrast used. Group I comprised patients with normal renal function in whom ICA was used exclusively, and group II patients had a serum creatinine >or=1.5 mg/dL, and CO(2)-DSA was used preferentially and supplemented with ICA, when necessary. The two groups were compared for the outcomes of successful graft placement, renal function, endoleak type, and frequency, and the need for graft revision. Comparisons were made using chi(2) analysis, Student t test, and the Fisher exact test.

RESULTS

A total of 84 EVARs were performed in group I and 16 in group II. Patient demographics and risk factors were similar between groups with the exception of serum creatinine, which was significantly increased in group II (1.8 mg/dL vs 1.0 mg/dL P < .0005). All 100 endografts were successfully implanted. Patients in group II had longer fluoroscopy times, longer operative times, and increased radiation exposure, and 13 of 16 patients required supplemental ICA. Mean iodinated contrast use was 27 mL for group II vs 148 mL in group I (P < .0005). Mean postoperative serum creatinine was unchanged from baseline, and 30-day morbidity was similar for both groups. No patient required dialysis. No patients died. Perioperatively, and at 1 and 6 months, the endoleak type and incidence and need for endograft revision was no different between groups.

CONCLUSIONS

CO(2)-DSA is safe, can be used to guide EVAR, and provides outcomes similar to ICA-guided EVAR. CO2-DSA protects renal function in the azotemic patient by lessening the need for iodinated contrast and associated nephrotoxicity, but with the tradeoff of longer fluoroscopy and operating room times and increased radiation exposure.

Endovascular repair versus open surgery in patients with ruptured abdominal aortic aneurysms: clinical outcomes with 1-year follow-up

OBJECTIVE

To compare the clinical outcomes of treatment after endovascular repair and open surgery in patients with ruptured infrarenal abdominal aortic aneurysms (AAAs), including 1-year follow-up.

METHODS

All consecutive conscious patients with ruptured infrarenal AAAs who presented to our tertiary care teaching hospital between January 1, 2001, and December 31, 2005, were included in this study (n = 55). Twenty-six patients underwent endovascular repair, and 29 patients underwent open surgery. Patients who were hemodynamically too unstable to undergo a computed tomography angiography scan were excluded. Outcomes evaluated were intraoperative mortality, 30-day mortality, systemic complications, complications necessitating surgical intervention, and mortality and complications during 1-year follow-up. The statistical tests we used were the Student t test, chi2 test, Fisher exact test, and Mann-Whitney U test (two sided; alpha = .05).

RESULTS

Thirty-day mortality was 8 (31%) of 26 patients who underwent endovascular repair and 9 (31%) of 29 patients who underwent open surgery (P = .98). Systemic complications and complications necessitating surgical intervention during the initial hospital stay were similar in both treatment groups (8/26 [31%] and 5/26 [19%] for endovascular repair, respectively, and 9/29 [31%] and 8/29 [28%] for open surgery, respectively; P > .40). During 1-year follow-up, two patients initially treated with endovascular repair died as a result of non-aneurysm-related causes; no death occurred in the open surgery group. Complications during 1-year follow-up were 1 (5%) of 20 for endovascular repair and 4 (16%) of 25 for open surgery (P = .36).

CONCLUSIONS

On the basis of our study with a highly selected population, the mortality and complication rates after endovascular repair may be similar compared with those after open surgery in patients treated for ruptured infrarenal AAAs.

The influence of aortic cuffs and iliac limb extensions on the outcome of endovascular abdominal aortic aneurysm repair

BACKGROUND

In a proportion of patients with an endovascular abdominal aortic aneurysm repair (EVAR), aortic cuffs or iliac graft limb extensions are required to enhance sealing or to fix the position of the device. This requirement arises when these goals are not primarily obtained with the basic stent-graft configuration. The aim of this study was to assess the influence of the use of endograft extensions during the primary EVAR procedure on the short- and long-term outcome.

METHODS

The study was based on the data of the EUROSTAR registry. Patient and anatomic characteristics, data regarding the procedure, postoperative complications, and the mortality of patients undergoing EVAR were retrieved from the database. Patients were divided into three groups: (1) no extensions, (2) proximal aortic cuffs, and (3) iliac limb extensions. Logistic regression and Cox proportional hazards models were used to compare significant influences of the use of cuffs or extensions on different outcomes relative to control patients, adjusted for patient and anatomic factors.

RESULTS

The overall cohort comprised 6668 patients: 4932 (74.0%) without extensions, 259 (3.9%) with an aortic cuff, and 1477 (22.2%) with an iliac endograft extension. Both the 30-day (2.3%-3.9%) and the all-cause mortality rates (23%-27% at 4 years) were similar in the three study groups. The use of proximal cuffs or iliac extensions did not have an effect on the incidence of endoleaks of any type (24%-32% at 4 years). The incidences of device kinking (P = .0344) and secondary transfemoral interventions (P = .0053) during follow-up were increased in patients in whom iliac limb extensions were used. In patients with aortic cuffs, no significant associations with altered outcome were observed.

CONCLUSIONS

The use of iliac graft limb extensions at EVAR was associated with a higher incidence of kinking and secondary transfemoral interventions, whereas proximal aortic cuffs did not influence outcome.

Current trends in the management of small abdominal aortic aneurysms

Over the past decade, there have been revolutionary changes in the diagnosis and treatment of abdominal aortic aneurysms. Minimally invasive endovascular technologies have decreased length of stay and, more importantly, improved at least the early outcomes compared with conventional open surgical therapy. Several large, randomized, prospective trials have re-evaluated the optimal size to treat abdominal aortic aneurysms. The guidelines and conclusions from these studies, the UK Small Aneurysm Trial and The Veterans Affairs Administration aneurysm Detection And Management Trial recommend intervening on aortic aneurysms when they reach 5.5 cm in transverse diameter. However, these studies do not bear direct relevance to contemporary management of aneurysms with endovascular techniques. Clinical trials are currently underway to assess the optimal size for treating abdominal aortic aneurysms with endovascular stent grafts.

Perioperative differences between endovascular repair of thoracic and abdominal aortic diseases

BACKGROUND

With the US Food and Drug Administration approval of the TAG thoracic device, more thoracic pathologies are being treated using endovascular techniques. Although endovascular abdominal and thoracic aortic repairs have some apparent similarities, there are substantive anatomic, pathologic, and technical differences that could impact perioperative outcomes. The purpose of this study is to identify these differences.

METHODS

During a 5-year period, 121 endovascular thoracic aortic repairs (TEVAR) and 450 abdominal aortic repairs (EVAR) were performed at a single institution. Preoperative, intraoperative, and early postoperative data were prospectively collected and retrospectively reviewed. Aggregate outcome measures were compared between the two cohorts, with statistical significance achieved at P < .05.

RESULTS

The mean age of patients undergoing EVAR was 72.8 +/- 8.3 compared with 68.3 +/- 13.9 for TEVAR (P = .02). More women underwent TEVAR (30.6% vs 11.1%, P < .001). Aneurysms undergoing TEVAR were larger than those for EVAR (62.0 mm vs 58.3 mm, P = .01). Intraoperatively, EVAR required 26.2 minutes of fluoroscopy compared with 22.1 minutes for TEVAR (P < .001). The amount of contrast used was higher in TEVAR (133.6 mL vs 93.6 mL, P < .001). The mean procedure times were 164 minutes for EVAR and 115 minutes for TEVAR (P < .001). Iliac conduits were required in 46 patients (10.2%) undergoing EVAR, and in 24 (19.8%) undergoing TEVAR (P = .007). The 30-day or in-hospital mortality was 2.0% for EVAR and 5.0% for TEVAR (P = NS). The median length of stay was longer for TEVAR (3 days vs 2 days, P =.034). There were 54 postoperative complications in 36 TEVAR patients (29.8%), including 13 neurologic (10.7%), 8 renal (6.6%), 7 pulmonary (5.8%), 6 ischemic (5.0), and 5 (4.1%) hemorrhagic events. Among the EVAR group, 136 (30.2%) patients had postoperative complications, which included 45 ischemic (10.0%), 34 wound (7.6%), 22 renal (4.9%), 12 cardiac (2.7%), 8 pulmonary (1.8%), 5 gastrointestinal (1.1%), and 4 neurologic (0.9%) events.

CONCLUSIONS

A relatively higher proportion of women underwent TEVAR than EVAR, and this was reflected in the greater need for iliac conduits to accommodate the larger delivery catheters of the thoracic devices. Intraoperative imaging techniques were also different, and TEVAR required higher contrast volumes despite shorter overall procedure times. The incidence of strokes and spinal cord ischemia was also higher during TEVAR. Despite apparent similarities of devices and techniques, EVAR and TEVAR are fundamentally different procedures with different perioperative outcomes.

Pathology, natural history and treatment of abdominal aortic aneurysms

With increasing age of the population and improvement of diagnostic tools, the incidence of abdominal aortic aneurysms (AAA) has been rising steadily. Despite an improvement in operative and interventional treatment options, AAA is the cause of death in 1-3% of men over 65 years of age in industrial countries, mostly due to rupture [1]. Therefore, routine screening for AAA by ultrasonography has been postulated in the past: a 60 year old man with an abdominal aortic diameter of less than 3 cm has a life-time risk of developing AAA close to zero. However, routine screening has not been found to be cost effective. Despite of the results of two well-designed studies, the limits of AAA qualifying the patient for surgery or intervention in contrast to conservative treatment is still a matter of debate. The present review article summarizes the current knowledge of the pathology, incidence, risks, natural course as well as symptoms and current treatment strategies of AAA on the basis of the recent literature.

Contemporary management of the infra-renal abdominal aortic aneurysm

Abdominal aortic aneurysms (AAAs) principally affect men over 60 years of age. Aneurysms are usually asymptomatic and detected coincidentally or following the onset of symptoms. Elective repair of an AAA is considered when the diameter reaches 5.5cm or annual expansion exceeds 1 cm. Rupture represents a catastrophic event and carries an unacceptably high mortality. The advent of endovascular repair heralds an improvement in operative outcome for this disease process. In this review we provide an overview of the recent trials investigating the management of non-ruptured and ruptured aneurysms and the strategies that may be invoked to lower the mortality of this disease process

Review of Interventional Repair for Abdominal Aortic Aneurysm

Abdominal aortic aneurysm is associated with high mortality rate. For over 50 years, open surgical repair was the standard approach for large aneurysms. However, over the past decade, endovascular aneurysm repair (EVAR) has emerged as a viable alternative. EVAR is associated with lower operative and short-term morbidity and mortality and similar long-term survival (up to 4 years) compared with surgical repair. Endoleak remains a significant limitation associated with aneurysm expansion and reintervention. With newer, more versatile endograft designs, improvements in durability, and better surveillance techniques, the utilization of EVAR is likely to continue to expand.

Outcome after hypogastric artery bypass and embolization during endovascular aneurysm repair

BACKGROUND

Multiple strategies have been devised to extend the applicability of endovascular aneurysm repair (EVAR) in patients with common iliac artery (CIA) aneurysms. This study was designed to examine outcome in patients undergoing EVAR with either hypogastric artery embolization or common iliac artery bifurcation advancement by hypogastric bypass.

METHODS

A retrospective review of all patients undergoing EVAR since the inception of our program (1997-2006) was performed. Data were prospectively collected in an EVAR registry. Patients with large common iliac artery aneurysms (> or = 20 mm) and patent hypogastric arteries not amenable to a cuff or "bell bottom" technique were treated with coil embolization (EMBO) and/or hypogastric revascularization (BYPASS). The perioperative and mid-term outcomes were compared with the larger group of patients undergoing EVAR that did not require either treatment (CTRL). Bilateral common iliac artery aneurysms were treated with unilateral coil embolization and contralateral bypass.

RESULTS

Common iliac artery aneurysms were present in 137 (31%) of the 444 patients undergoing EVAR, but only 57 (42%) of 137 required direct management. This included hypogastric artery embolization alone (EMBO) in 31 or hypogastric artery revascularization (BYPASS) in 26, with and without contralateral embolization (both revascularization/embolization in 46%). The procedure length (CTRL, 159 +/- 72 minutes; EMBO, 153 +/- 39 minutes; BYPASS, 283 +/- 75 minutes) and estimated blood loss (CTRL, 251 +/- 313 mL; EMBO, 233 +/- 158 mL; BYPASS, 400 +/- 287 mL) were significantly greater (P < .05) in the BYPASS group. The incidence of any postoperative complication (CTRL, 26%; EMBO, 68%; BYPASS, 54%), any ischemic complication (CTRL, 6%; EMBO, 55%; BYPASS, 27%), and new-onset buttock claudication (CTRL, 3%; EMBO, 39%; BYPASS, 27%) were all significantly greater in the BYPASS and EMBO group relative to the control (CTRL) group (n = 387). The incidence of new-onset buttock claudication ipsilateral to the hypogastric bypass was 4%; the balance of the new onset claudication in the BYPASS group was due to the contralateral embolization. The primary hypogastric artery bypass patency was 91 +/- 11% (SE) at 36 months by life-table analysis.

CONCLUSIONS

Despite its increased complexity, hypogastric artery bypass is an excellent alternative to embolization in terms of patency and freedom from ischemic symptoms for patients with large common iliac artery aneurysms undergoing EVAR.

From Innumeracy to Insight: The Uncertainty of Help versus Harm in Treatment of Asymptomatic Aortic Aneurysms

There is insufficient evidence that the surgical treatment of asymptomatic infrarenal aneurysms > 5.5 cm. is beneficial to patients. This is the result of serious complications of aneurysm surgery and the dearth of information from randomized trials. Based on evidence from the literature we defined scenarios and translated data into natural frequency trees to improve understanding of the uncertainty of help versus harm due to treatment of aneurysms. Our analysis shows that the majority of patients can expect little on longevity from surgery while they are at risk of dying from surgery or suffering from serious morbidity. We conclude that, as long as uncertainty persist, patients should be treated in hospitals that can show very low surgical mortality and major morbidity rates. To further resolve the problem of uncertainty randomized trials for larger aneurysms should be performed. Important issues to discuss are the lower and upper limits of the diameter of the aneurysms and the age and risk profiles of the patients to be included in such trials.

Patient-reported quality of life after abdominal aortic aneurysm surgery: A prospective comparison of endovascular and open repair

PURPOSE

This study evaluated and compared changes over time in health-related quality of life reported by patients with infrarenal abdominal aortic aneurysm (AAA) undergoing elective endovascular (EVAR) and open aneurysm (OR) repair.

METHODS

A prospective, nonrandomized cohort of 76 patients (62 men, 14 women; age range, 42 to 89 years) undergoing elective, infrarenal AAA repair (EVAR, n = 43; OR, n = 33) at two university teaching hospitals during a 15-month period were administered the Medical Outcomes Study Short-Form 36-item (SF-36) health survey preoperatively and then 1 week, 1 month, and 6 months postoperatively. Patient demographics, procedural details, postoperative follow-up data, and SF-36 scores were compared between groups.

RESULTS

Both groups had total SF-36 scores that were significantly lower than preoperative scores at 1 week and 1 month after surgery but were not significantly different from the preoperative scores at 6 months (OR 66.2 +/- 21.1 to 72.3 +/- 19.8, P > .1; and EVAR 61.0 +/- 17.7 to 58.7 +/- 19.4, P > .1). Six-month total SF-36 scores were significantly higher in the OR group compared with the EVAR group (mean 72.3 +/- 19.8 OR vs 58.7 +/- 19.4 EVAR; P = .009). In the postoperative period, a significant drop occurred in mean scores in six of the eight domains of the SF-36 in the OR patients (physical function, PF; role physical, RP; bodily pain, BP; vitality, VT; social function, SF; role emotional, RE) and five domains for EVAR patients (PF, RP, BP, SF, RE). In two domains, RE and PF, scores returned to baseline values significantly sooner in EVAR patients than in OR patients (RE, EVAR 1 month vs OR 6 months; and PF, EVAR 1 month vs OR 6 months). In the VT domain, no significant postoperative drop occurred in the EVAR group, but in the OR group, mean scores were significantly lower at 1 week and 1 month compared with preoperative values. In the domains of general health and mental health, no significant drop occurred in SF-36 score postoperatively in either group.

CONCLUSIONS

Patient reported health-related quality of life after infrarenal AAA repair is significantly impaired in the early postoperative period but returns to baseline by 6 months in patients treated with EVAR and OR. Patients having EVAR had significantly more rapid return to preoperative scores in selected domains of the SF-36. Even though EVAR is associated with shorter and less invasive perioperative hospital course and fewer postoperative complications, EVAR patients had lower quality of life scores 6 months after surgery than OR patients.

Abdominal Aortic Aneurysm: Can the Arterial Phase at CT Evaluation after Endovascular Repair Be Eliminated to Reduce Radiation Dose?

PURPOSE

To retrospectively determine if arterial phase computed tomographic (CT) imaging is necessary for follow-up imaging of patients who have undergone endovascular stent-graft therapy for abdominal aortic aneurysm.

MATERIALS AND METHODS

This HIPAA-compliant study was exempt from institutional review board approval; informed patient consent was waived. Eighty-five patients (66 men, 19 women; mean age, 66 years; range, 45-81 years) underwent 110 multidetector CT examinations after endovascular repair of abdominal aortic aneurysms. Nonenhanced CT images were obtained. Intravenous contrast material was then injected at 4 mL/sec, and arterial and venous phase (60 seconds) CT images were obtained. The nonenhanced and venous phase images were evaluated to determine if an endoleak was present. Subsequently, arterial phase images were analyzed. The effective dose was calculated. Ninety-five percent confidence intervals as indicators of how often arterial phase imaging would contribute to the diagnosis of endoleak were determined.

RESULTS

Twenty-eight type II endoleaks were detected by using combined nonenhanced and venous phase acquisitions. Twenty-five of the 28 endoleaks were also visualized during the arterial phase. Three type II endoleaks were seen only during the venous phase. The arterial phase images depicted no additional endoleaks. Seventy-eight CT examinations performed in 67 patients revealed no endoleak during the venous phase. The arterial phase images also depicted no endoleaks at these examinations. Thus, for no more than 3.1% of all examinations, there was 95% confidence that arterial phase imaging would depict an endoleak missed at venous phase imaging. Arterial phase imaging contributed to a mean of 36.5% of the effective dose delivered.

CONCLUSION

Study results indicate that arterial phase imaging may not be necessary for the routine detection of endoleaks. Radiation exposure can be decreased by eliminating this phase.

HLA-DR expression on monocytes and systemic inflammation in patients with ruptured abdominal aortic aneurysms

Introduction

Mortality from ruptured abdominal aortic aneurysms (RAAA) remains high. Severe systemic inflammation, leading to multi-organ failure, often occurs in these patients. In this study we describe the level of HLA-DR expression in a consecutive group of patients following surgery for RAAA and compare results between survivors and non-survivors. A similar comparison is made for IL-6 and IL-10 levels and Sequential Organ Failure Assessment (SOFA) scores.

Methods

This is a prospective observational study. Patients with RAAA were prospectively analysed. Blood samples were collected on days 1, 3, 5, 7, 10 and 14. The fraction of CD-14 positive monocytes expressing HLA-DR was measured by flow-cytometry. IL-6 and IL-10 levels were measured by ELISA.

Results

The study included 30 patients with a median age of 70 years, of which 27 (90%) were men. Six patients died from multiple organ failure, all other patients survived. The SOFA scores were significantly higher in non-survivors on days 1 through 14. HLA-DR expression on monocytes was significantly lower on days 3, 5, 7, 10 and 14 in non-survivors. IL-6 and IL-10 levels were significantly higher in non-survivors on day 1 and days 1 and 3, respectively.

Conclusion

HLA-DR expression on monocytes was decreased, especially in non-survivors. All patients with RAAA displayed a severe inflammatory and anti-inflammatory response with an increased production of IL-6 and IL-10. Poor outcome is associated with high levels of IL-6 and IL-10 and a high SOFA score in the first three days after surgery, while low levels of HLA-DR expression are observed from day three after RAAA repair.

Current Status of Endovascular Repair of Infrarenal Abdominal Aortic Aneurysms in the Context of 50 Years of Conventional Repair

The operative risk for conventional open repair of nonruptured infrarenal abdominal aortic aneurysms (AAAs) has steadily declined during the past several decades to the point that open procedures now can be done with a mortality rate of approximately 2% at tertiary referral centers. Nevertheless, population-based studies suggest that the mortality rate for open AAA repair remains nearly 7% in many communities, a finding that undoubtedly is influenced by a substantial risk for unfavorable outcomes in patients who represent less than ideal candidates for major abdominal operations on the basis of advanced age and the medical comorbidities that so often accompany it. Endovascular aneurysm repair (EVAR) is a landmark contribution to the management of such patients and has been associated with significant overall reductions in the operative mortality rate in statewide and national audits. This early advantage of EVAR comes at the price of a unique set of complications, secondary interventions, and related expenses, however, and randomized clinical trials of EVAR versus open repair have not yet demonstrated differences in survival or quality of life within 4 years of follow-up. Data from the Nationwide Inpatient Sample and other sources indicate that the mortality rate for open AAA repair appears to be less than 2% in patients who are 65 years of age or younger. This low operative risk may not justify exposure to whatever incidence of late complications the current generation of endografts may prove to have during the relatively long survival times that can be anticipated for these patients.

Endovascular Treatment of Peripheral Vascular Disease

An estimated 10 million people in the U.S. have symptomatic peripheral arterial disease (PAD); 20 to 30 million have asymptomatic PAD. The prevalence of intermittent claudication increases with age, affecting >5% of patients over 70. The incidence of claudication doubles or triples in patients with diabetes. As people grow older, symptoms from peripheral vascular disease increasingly limit daily activity. Until recently, vascular surgical procedures were the only alternative to medical therapy in such patients. Today, advances in minimally invasive percutaneous interventions have made endovascular procedures the primary modality for revascularization in most patients. Compared with open surgical procedures, endovascular interventions offer comparable or superior long-term rates of success with very low rates for morbidity and mortality. Furthermore, most of these interventions are performed on an outpatient basis, reducing hospital stays considerably. In this monograph we discuss current endovascular interventions for treating occlusive PAD, aneurysmal arterial disease, and increasingly common venous occlusive diseases.

Duplex Ultrasound Scanning is Reliable in the Detection of Endoleak Following Endovascular Aneurysm Repair

OBJECTIVE

To investigate the value of duplex ultrasound scanning (DUSS) in the routine follow up of patients following EVAR.

METHODS

Imaging was reviewed for 310 consecutive patients undergoing EVAR at a single centre. Concurrent ultrasound and CT scans were defined as having occurred within 6 months of each other. There were 244 paired concurrent DUSS and CT scans which were used for further analysis. These modalities were compared with respect to sensitivity, specificity, positive and negative predictive values and level of agreement (by Kappa statistics) using CT as the 'gold standard'.

RESULTS

DUSS failed to detect a number of endoleaks which were seen on CT and the sensitivity of this test was therefore poor (67%). However, the specificity of DUSS compared more favourably with a value of 91%. Positive predictive values ranged from 33-100% but negative predictive values were more reliable with values of 91-100% at all time points post operatively. There were no type I leaks, or endoleaks requiring intervention which were missed on DUSS. Overall, there was a 'fair' level of agreement between the two imaging modalities using Kappa statistics.

CONCLUSION

Although DUSS is not as sensitive as CT scanning in the detection of endoleak, no leaks requiring intervention were missed on DUSS in this study. DUSS is much cheaper than CT and avoids high doses of radiation. DUSS therefore remains a valuable method of follow up after EVAR and can reduce the need for repeated CT scans.

Endovascular aneurysm repair at 5 years: does aneurysm diameter predict outcome?

OBJECTIVE

The appropriate size threshold for endovascular repair of small abdominal aortic aneurysms (AAA) is unclear. We studied the outcome of endovascular aneurysm repair (EVAR) as a function of preoperative aneurysm diameter to determine the relationship between aneurysm size and long-term outcome of endovascular repair.

METHODS

We reviewed the results of 923 patients treated in a prospective, multicenter clinical trial of EVAR. Small aneurysms were defined according to two size thresholds of 5.5 cm and 5.0 cm. Two-way analysis was used to compare patients with small aneurysms (<5.5 cm, n = 441) to patients with large aneurysms (> or =5.5 cm, n = 482). An ordered three-way analysis was used to compare patients with small AAA (<5.0 cm, n = 145), medium AAA (5.0 to 5.9 cm, n = 461), and large AAA (> or =6.0 cm, n = 317). The primary outcome measures of rupture, AAA-related death, surgical conversion, secondary intervention, and survival were compared using Kaplan-Meier estimates at 5 years.

RESULTS

Median aneurysm size was 5.5 cm. The two-way comparison showed that 5 years after EVAR, patients with small aneurysms (<5.5 cm) had a lower AAA-related death rate (1% vs 6%, P = .006), a higher survival rate (69% vs 57%, P = .0002), and a lower secondary intervention rate (25% vs 32%, P = .03) than patients with large aneurysms (> or =5.5 cm). Three-way analysis revealed that patients with small AAAs (<5.0 cm) were younger (P < .0001) and were more likely to have a family history of aneurysm (P < .05), prior coronary intervention (P = .003), and peripheral occlusive disease (P = .008) than patients with larger AAAs. Patients with smaller AAAs also had more favorable aortic neck anatomy (P < .004). Patients with large AAAs were older (P < .0001), had higher operative risk (P = .01), and were more likely to have chronic obstructive pulmonary disease (P = .005), obesity (P = .03), and congestive heart failure (P = .004). At 5 years, patients with small AAAs had better outcomes, with 100% freedom from rupture vs 97% for medium AAAs and 93% for large AAAs (P = .02), 99% freedom from AAA-related death vs 97% for medium AAAs and 92% for large AAAs (P = .02) and 98% freedom from conversion vs 92% for medium AAAs and 89% for large AAAs (P = .01). Survival was significantly improved in small (69%) and medium AAAs (68%) compared to large AAAs (51%, P < .0001). Multivariate Cox proportional hazards modeling revealed that aneurysm size was a significant independent predictor of rupture (P = .04; hazard ratio [HR], 2.195), AAA-related death (P = .03; HR, 2.007), surgical conversion (P = .007; HR, 1.827), and survival (P = .001; HR, 1.351). There were no significant differences in secondary intervention, endoleak, or migration rates between small, medium, and large AAAs.

CONCLUSIONS

Preoperative aneurysm size is an important determinant of long-term outcome following endovascular repair. Patients with small AAAs (<5.0 cm) are more favorable candidates for EVAR and have the best long-term outcomes, with 99% freedom from AAA death at 5 years. Patients with large AAAs (> or =6.0 cm) have shorter life expectancy and have a higher risk of rupture, surgical conversion, and aneurysm-related death following EVAR compared to patients with smaller aneurysms. Nonetheless, 92% of patients with large AAAs are protected from AAA-related death at 5 years. Patients with AAAs of intermediate size (5 to 6 cm) represent most of the patients treated with EVAR and have a 97% freedom from AAA-related death at 5 years.

A Summary of the Contributions of the VA Cooperative Studies on Abdominal Aortic Aneurysms

The Department of Veterans Affairs Cooperative Studies Program has completed two studies on abdominal aortic aneurysm (AAA) and is currently conducting a third. The first, the Aneurysm Detection and Management (ADAM) Study, consisted of both a screening program, which provided information on the prevalence and associations of AAA, and a randomized trial, which found that survival is not improved by repair of small AAA. The second was a prospective observational study to determine the incidence of rupture in patients with large AAA for whom elective repair was not planned due to medical contraindications or patient refusal. AAA in this population had a high risk of rupture, about 10% per year for AAA > 5.5 cm, and 25% within 6 months for AAA larger than 8.0 cm. The third, the Open Versus Endovascular Repair (OVER) Trial, is a multicenter randomized trial comparing long-term survival following two methods of elective AAA repair.

Long-term outcomes after endovascular abdominal aortic aneurysm repair: the first decade

OBJECTIVE

The proper role of endovascular abdominal aortic aneurysm repair (EVAR) remains controversial, largely due to uncertain late results. We reviewed a 12-year experience with EVAR to document late outcomes.

METHODS

During the interval January 7, 1994 through December 31, 2005, 873 patients underwent EVAR utilizing 10 different stent graft devices. Primary outcomes examined included operative mortality, aneurysm rupture, aneurysm-related mortality, open surgical conversion, and late survival rates. The incidence of endoleak, migration, aneurysm enlargement, and graft patency was also determined. Finally, the need for reintervention and success of such secondary procedures were evaluated. Kaplan-Meier and multivariate methodology were used for analysis.

RESULTS

Mean patient age was 75.7 years (range, 49-99 years); 81.4% were male. Mean follow-up was 27 months; 39.3% of patients had 2 or more major comorbidities, and 19.5% would be categorized as unfit for open repair. On an intent-to-treat basis, device deployment was successful in 99.3%. Thirty-day mortality was 1.8%. By Kaplan-Meier analysis, freedom from AAA rupture was 97.6% at 5 years and 94% at 9 years. Significant risk factors for late AAA rupture included female gender (odds ratio OR, 6.9; P = 0.004) and device-related endoleak (OR, 16.06; P = 0.009). Aneurysm-related death was avoided in 96.1% of patients, with the need for any reintervention (OR, 5.7 P = 0.006), family history of aneurysmal disease (OR, 9.5; P = 0.075), and renal insufficiency (OR, 7.1; P = 0.003) among its most important predictors. 87 (10%) patients required reintervention, with 92% of such procedures being catheter-based and a success rate of 84%. Significant predictors of reintervention included use of first-generation devices (OR, 1.2; P < 0.01) and late onset endoleak (OR, 64; P < 0.001). Current generation stent grafts correlated with significantly improved outcomes. Cumulative freedom from conversion to open repair was 93.3% at 5 through 9 years, with the need for prior reintervention (OR, 16.7; P = 0.001) its most important predictor. Cumulative survival was 52% at 5 years.

CONCLUSIONS

EVAR using contemporary devices is a safe, effective, and durable method to prevent AAA rupture and aneurysm-related death. Assuming suitable AAA anatomy, these data justify a broad application of EVAR across a wide spectrum of patients.

Propensity score analysis in observational studies: outcomes after abdominal aortic aneurysm repair

OBJECTIVE

Large databases composed of well-designed prospectively collected cohort data provide an opportunity to examine and compare healthcare treatments in actual clinical practice settings. Because the analysis of these data often leads to a retrospective cohort design, it is essential to adequately adjust for lack of balance in patient characteristics when making treatment comparisons. We used matched propensity scoring in a cohort of patients undergoing elective aneurysm repair as an illustrative example of this important statistical method that adjusts for baseline characteristics and selection bias by matching covariables.

METHODS

By using prospectively collected clinical data from the National Surgical Quality Improvement Program of the Department of Veterans Affairs, we studied 30-day mortality, 1-year survival, and postoperative complications in 1904 patients who underwent elective AAA repair (endovascular aneurysm repair [EVAR], n=717 (37.7%); open aneurysm repair, n=1187 [62.3%]) at 123 Veterans Health Administration's hospitals between May 1, 2001, and September 30, 2003. In bivariate analysis, patient characteristics and operative and hospital variables were associated with both type of surgery and outcomes of surgery. Therefore, the predicted probability of receiving EVAR was tabulated for all patients by using multiple logistic regression to control for 32 independent demographic and clinical characteristics and then stratified into 5 groups. Patients were matched within strata based on similar levels of the independent measures (a propensity score technique), creating a pseudo-randomized control design. The proportion of patients with the morbidity and mortality outcomes was then compared between the EVAR and open procedures within strata to control for selection.

RESULTS

Patients undergoing EVAR had significantly lower unadjusted 30-day (3.1% versus 5.6%, P=.01) and 1-year mortality (8.7% versus 12.1%, P=.018) than patients undergoing open repair. By using propensity scoring, the proportions of EVAR patients experiencing 30-day mortality were equal or less than patients undergoing open procedures for all levels of probability and decreased as the probability of EVAR increased. Furthermore, propensity scoring also showed that patients having EVAR had lower 1-year mortality and experienced fewer perioperative complications.

CONCLUSIONS

We used a propensity score approach to examine outcomes after elective AAA repair to statistically control for many factors affecting both treatment selection and outcome. Patients who underwent elective EVAR had substantially lower perioperative mortality and morbidity rates compared with patients having open repair, which was not explained solely by patient selection in an observational dataset.

Complications of Endovascular Repair of Abdominal Aortic Aneurysms: A Review

The endovascular procedure for repair of abdominal aortic aneurysms has had an enormous impact on the treatment of this challenging disease. Complications, however, do occur and it is important to have a thorough understanding of the array of complications and appropriate management strategies. In this review of endovascular complications, we describe early and late complications paying particular attention to preventive, treatment and surveillance strategies.

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.

Mid-term results of endovascular aneurysm repair with branched and fenestrated endografts

PURPOSE

The technique of fenestrated and branched endovascular aneurysm repair (EVAR) has been used for the treatment a variety of aortic aneurysms. Although technically successful, longer-term results have been lacking. This article reports on the mid-term results of aneurysm repair with fenestrated and branched endografts from a European center with a large endovascular experience.

METHODS

Between 2001 and 2005, 38 patients were prospectively enrolled in a single institution, investigational device protocol database. Indications for fenestrated or branched EVAR included unfavorable anatomy for traditional EVAR and an abdominal aortic aneurysm >5.5 cm in maximum diameter. Customized stent-grafts were either fenestrated or branched and based on the Zenith system. Data were analyzed on an intention-to-treat basis. Differences between groups were determined using analysis of variance with P < .05 considered significant.

RESULTS

The mean (SD) follow-up was 25.8 +/- 12.7 months (median, 25.0 months; range, 9 to 46 months), and no patients were lost to follow-up. All cause mortality was 13% (5/38), with all deaths occurring within the first postoperative year; 30-day mortality was 2.6%. No patient died during the operation. Completion angiography demonstrated successful sealing in 37 of 38 patients and an overall operative visceral vessel perfusion rate of 94% (82/87). Cumulative visceral branch patency was 92% at 46 months. Stent occlusions, when they did occur, all happened within the first postoperative year. All postoperative occlusions occurred in unstented fenestrations or scallops. No occlusions occurred in stented vessels. The difference in serum creatinine preoperatively and postoperatively at 6 months, 1, 2, and 3 years was not significant (P = NS). No patient required dialysis. The aneurysm sac size decreased significantly during the first year and then remained stable (P < .05). Limb perfusion as assessed by the ankle/brachial index was not affected by the presence of a fenestrated or branched endograft.

CONCLUSIONS

The intermediate-term results of fenestrated and branched endografts support their continued use in patients with anatomic contraindications for standard EVAR. Close surveillance is mandatory for early identification of visceral or branched vessel stenosis and preocclusion. All cases of failure appear to occur during the first year and then level off in subsequent longer-term follow-up. This includes death, secondary interventions, branch vessel patency, and complications. As the procedure matures, long-term results and randomized clinical trials will ultimately be required to determine the safety, efficacy, and stability of this system.