Nature, frequency, and predictors of secondary procedures after endovascular repair of abdominal aortic aneurysm

Ten-Year Outcomes after Endovascular Aneurysm Repair (Evar) and Magnitude of Additional Procedures

Background and Aims:

With any new technology complications are possible, and problems with first-generation aortic stentgrafts have been extensively reported. The long-term outcome of this patient population and the magnitude of additional secondary procedures are, however, less well covered.

Materials and Methods:

Between February 1997 and November 1999, 48 patients (44 men and 4 women; mean age 70 years; range 54–85) with AAA (average 57mm, range 40–90mm) were treated with a Vanguard® endoprosthesis. Stentgrafts were sized by CT and angiography-based measurements. Results were continuously assessed using contrast-enhanced CT before discharge, 1, 3, 6 and 12 months after the procedure and thereafter annually. Since 2001 plain abdominal X-rays have been performed annually.

Results:

The technical implant success rate was 100%. Median follow-up was 91 months (range 7.6–120 months). None of the patients was lost during this period. Hospital mortality was 0%. There were 25 subsequent deaths (52%), the most common cause being coronary artery disease. There were ten late conversions to open surgical repair, including three emergency operations: two due to rupture and one to thrombosis. EVAR-related complications were encountered in 43 patients (90%): 12 primary endoleaks (all type II), 36 late endoleaks (16 type I, 2 type II and 18 type III), 22 migrations, 25 row separations, 20 thromboses, one endotension and 3 ruptures of the AAA. Secondary procedures were required in 39 patients (81%): 1 re-endografting by aortoiliac bifurcated graft and 3 with a uni-iliac graft; 33 limb graft repairs were performed and 19 infrarenal cuffs were placed. There were 4 late embolizations and 4 attempts, and 6 thrombolyses, four of which were successful. Further, 9 femoro-femoral crossover by-pass and 2 axillo-femoral by-pass operations and 2 amputations were carried out during the follow-up. Only one patient was alive without complications.

Conclusions:

The impact of long-term follow-up of patients treated with the new technology was emphasized in this patient population. A careful surveillance protocol and active endovascular treatment of complications can yield acceptable results and low AAA rupture and aneurysm mortality rates, also with the first-generation endovascular graft. A new technology, however, may involve unpredictable problems which can magnify the workload and incur high costs over several years after the initial procedure.

Re-interventions after endovascular aortic repair for infrarenal abdominal aneurysms: a retrospective cohort study

Background

Early morbidity and mortality are generally lower after endovascular aortic repair (EVAR), than after open repair but re-interventions and late complications are more common. The aim of the present study was to make a detailed description of re-interventions after EVAR-including incidence, indications, procedures, and outcome-with special reference to non-access-related re-interventions.

Methods

This is a retrospective single-center cohort study of re-interventions after standard EVAR with special reference to non-access-related re-interventions. Consecutive patients (n = 405) treated with standard EVAR for non-ruptured (n = 337) or ruptured (n = 68) infrarenal aneurysms between 2005 and 2013 were analysed. Median follow-up was 29 months (range 0–108).

Results

Eighty-nine patients (22 %) underwent 113 re-interventions during follow-up. Twenty-seven patients (7 %) had 28 access related re-intervention, 65 patients (16 %) had 85 non-access related reinterventions. Non-access related re-interventions were more common in ruptured aneurysms than in unruptured aneurysms (22 vs. 15 %, p = 0.002). The most frequent indications were endoleak type I (n = 19), type II (n = 21), or type III (n = 5); stent graft migration (n = 9); and thrombosis (n = 14). The most frequent procedures were embolization of endoleak type II (n = 21), additional iliac stent graft (n = 19), proximal extension (n = 12), thrombolysis (n = 8), iliac limb bare-metal stenting (n = 6), and stent graft relining (n = 7). Endovascular technique was used in 83 % of re-interventions.

Thirty-day mortality after non-access-related re-interventions was 15 % when initiated from symptoms (rupture or infection) and 0 % when initiated from follow-up findings (p = 0.014). Cumulative survival five years after EVAR was 72 % in patients with a re-intervention and 59 % in patients without (p = 0.21).

Conclusions

Non-access-related re-intervention rates are still considerable after EVAR and more frequent after ruptured aneurysms. Endoleak embolization is the most frequent procedure, followed by additional iliac stent grafts. Outcomes after re-interventions are generally good, except when initiated by rupture or infection.

Novel Risk Score Model for Prediction of Survival Following Elective Endovascular Abdominal Aortic Aneurysm Repair

OBJECTIVE

The purpose of this study was to identify significant predictors of long-term mortality after elective endovascular abdominal aortic aneurysm repair (EVAR).

METHODS

We included all cases with elective EVAR based on a national data set from the Society for Vascular Surgery Patient Safety Organization. Clinical and anatomic variables were analyzed with a Kaplan-Meier and Cox-regression model to determine predictors of mortality and develop a score equation to categorize patients into low, medium, and high long-term mortality risk.

RESULTS

A total of 5678 patients with EVAR were included with an average age of 73.6 ± 8.2 years. The majority were male (81.6%) with a history of smoking (86.1%). There were 3 deaths within 30 days (0.1%). Several factors were associated with poor survival: unstable angina (hazard ratio [HR], 2.8; P = .008), dialysis (HR, 3.7; P < .001), estimated glomerular filtration rate (eGFR) <30 (HR, 1.7; P = .044), eGFR 30 to 59 (HR, 1.4; P = .002), age >80 (HR, 3.2; P < .001), age 75 to 79 (HR, 2.2; P < .001), chronic obstructive pulmonary disease on oxygen (HR, 3.3; P < .001), aortic diameter >5.8 cm (HR, 1.2; P = .043), and high risk for surgery (HR, 1.4; P = .043). Preoperative aspirin use and body mass index 25 to 35 were both found to be protective (HR, 0.78; P = .017 and HR, 0.8; P = .024, respectively). With our scoring model, 5- and 10-year survival rates for patients with low, medium, and high risk were 89.2%, 80.7%, and 64.1% and 77.2%, 60.1%, and 40.1%, respectively (P < .001).

CONCLUSION

Ten-year survival following EVAR in patients with a high-risk score utilizing the model provided was 40.1%. Patients with multiple comorbidities at risk for decreased long-term survival can be identified with our model, which is more applicable for high-volume contemporary institutions.

Intraoperative contrast-enhanced cone beam computed tomography to assess technical success during endovascular aneurysm repair

BACKGROUND

The aim of the study was to analyze the use of contrast-enhanced cone beam computed tomography (ceCBCT) during endovascular aneurysm repair (EVAR) and to compare this imaging modality with standard completion digital subtraction angiography (cDSA) and postoperative computed tomography angiography (CTA) regarding the detection of endograft-associated complications.

METHODS

Between September 2012 and April 2015, ceCBCT was used in 98 EVAR patients in addition to cDSA and CTA. Endoleaks, intraluminal thrombus and limb stenoses, contrast agent use, and radiation exposure were recorded for all modalities.

RESULTS

cDSA detected 16 (16.3%) endoleaks; ceCBCT, 35 (35.7%) endoleaks; and CTA, 22 (22.4%) endoleaks. All endoleaks identified by cDSA or CTA were also seen on ceCBCT. ceCBCT detected intraluminal thrombus in three patients (none in cDSA or CTA) and previously undetected limb stenoses in three patients. It prompted intraoperative interventions in 7 of 98 patients (7.1%). Replacing cDSA and CTA by ceCBCT would have caused a 39% reduction of in-hospital contrast agent volume in this cohort.

CONCLUSIONS

ceCBCT can reliably detect all endograft-associated complications during EVAR. It offers the chance for immediate revision of remediable problems in a relevant proportion of patients and could thus reduce early reintervention rates. ceCBCT can safely replace early follow-up CTA and thereby reduce in-hospital use of contrast media.

Stent graft types for endovascular repair of abdominal aortic aneurysms

BACKGROUND

The UK prevalence of abdominal aortic aneurysm (AAA) is estimated at 4.9% in over 65-year olds. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of AAAs involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market. This is an update of the review first published in 2013.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of AAA.

SEARCH METHODS

The Cochrane Vascular Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched February 2015) and the Cochrane Register of Studies (2015, Issue 1). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of AAAs were sought without language restriction and in consultation with the Cochrane Vascular Group TSC.

DATA COLLECTION AND ANALYSIS

We planned to conduct data collection and analysis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria. It was not possible to review the quality of the evidence in the absence of studies eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. High quality randomised controlled trials evaluating stent graft types in abdominal endovascular aneurysm repair are required.

Stent graft types for endovascular repair of thoracic aortic aneurysms

BACKGROUND

The UK prevalence of thoracic aneurysm is estimated at 10.4 per 100,000 person-years. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of thoracic aortic aneurysms involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market. This is an update of the review first published in 2013.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of thoracic aortic aneurysms.

SEARCH METHODS

The Cochrane Vascular Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched February 2015) and the Cochrane Register of Studies CENTRAL (2015, Issue 1). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of thoracic aortic aneurysms were sought without language restriction.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria. It was not possible to assess the quality of the evidence in the absence of studies eligible for inclusion in the review.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. High quality RCTs evaluating stent graft types in thoracic endovascular aneurysm repair are required.

Open Surgical Repair Can Be One Option for the Treatment of Persistent Type II Endoleak after EVAR

PURPOSES

Endovascular abdominal aortic aneurysm repair (EVAR) is an increasingly used method of repairing abdominal aortic aneurysm (AAA). However, the treatment of persistent type II endoleak is still a controversial issue. Five cases are reported here in which we performed open surgical repair of growing aneurysm due to persistent type II endoleak.

METHOD

Totally 128 EVAR cases were retrospectively reviewed, which were operated in our hospital from April 2008 to October 2013. These cases were followed by periodical contrast-enhanced computed tomography (CT) after EVAR. When persistent type II endoleak caused aneurysm sac growth, we performed surgical repair method for the first line treatment. In the operation, we incised the aneurysm sac by abdominal small median incision approach and sutured lumber arteries from inside of aneurysm sac and tied inferior mesenteric artery (IMA) in addition to aneurysmorrhaphy. Contrast-enhanced CT scanning was performed in a week after open repair for the confirmation of complete treatment.

RESULTS

Five of 128 cases (3.9%) were needed to be surgically repaired because of aneurysm sac growth (>5 mm), including two ruptured AAA cases. All patients recovered uneventfully. Contrast-enhanced CT scanning performed a week after these operations showed no endoleak and intact stent grafts and reduction of the aneurysm size.

CONCLUSION

We believe open surgical repair method of persistent type II endoleak with aneurysm expansion is secure method, and can be one of the preferable options for this life threatening complication after EVAR.

Studying the Interaction of Stent-Grafts and Treated Abdominal Aortic Aneurysms

Since the advent of endovascular repair of aortic aneurysms (EVAR), clinical focus has been on preventing loss of sealing at the level of the infrarenal neck, which leads to type I endoleak and repressurization of the aneurysm sac. Enhanced mechanisms for central fixation and seal have consequently lowered the incidence of migration and endoleaks. However, endograft limb thrombosis and its causal mechanisms have not been addressed adequately in the literature. This article reviews the pathophysiological mechanisms associated with limb thrombosis in order to facilitate better clinical judgment to prevent iliac adverse effects.

A 12-Year Experience With Chimney and Periscope Grafts for Treatment of Type I Endoleaks

Purpose: To evaluate the midterm outcomes of chimney and/or periscope grafts (CPGs) in patients presenting type I endoleak after a previous endovascular aneurysm repair (EVAR). Methods: Between June 2002 and April 2014, 24 consecutive patients (mean age 73.9±9.2 years; 23 men) presenting a type I endoleak were addressed with CPGs to extend the proximal and/or distal landing zone and to maintain side branch perfusion. Indication for treatment was a type Ia endoleak in 23 (96%) patients and a type Ib endoleak in one. Median interval from the previous EVAR to endoleak treatment with CPGs was 52.2±48.9 months (range 0.2–179). All patients had proximal/distal landing zones precluding any standard endovascular reintervention. Measured outcomes included technical success and perioperative mortality and morbidity. Technical success was defined as a procedure completed as intended, with no secondary procedures within 30 days. Midterm outcomes included survival, CPG patency, endoleaks, and freedom from reintervention. Results: Technical success was 96%; a single patient required an additional procedure to seal a recurrent type Ia endoleak. Intraoperative revascularization of all 55 target vessels (2.3/patient) with CPGs was successful. One (4%) patient died within 30 days. Estimated survival at 12, 24, and 36 months was 83%; estimated CPG patency at the same intervals was 94%. Over a mean follow-up of 23.4±29 months, 6 (25%) reinterventions were performed; of these, 4 were secondary to type I endoleak. Aneurysm diameters reduced from 88.3±26 to 85.5±33 mm (p=0.49) over the mean follow-up. Conclusion: The CPG technique is a safe and effective tool for treatment of type I endoleak after previous EVAR. The CPG technique is feasible even in nonelective patients, with excellent outcomes in terms of patency. Close imaging follow-up is warranted to rule out recurrent or de novo endoleaks.

Surgical infrarenal "neo-neck" technique during elective conversion after EVAR with suprarenal fixation

OBJECTIVES

Conversion of a previous endovascular aneurysm repair (EVAR) with suprarenal fixation is a challenging situation even in the elective setting. The outcomes of a technique based on preservation of the first proximal covered stent of the endograft, used as a "neo-neck" for proximal anastomosis, are presented.

METHODS

From 2001 to 2014, nine patients underwent elective conversion of a previous suprarenally fixed EVAR. After supraceliac clamping, the aneurysm sac was opened and the endograft identified; the fabric was cut beyond the first covered stent together with its native aortic wall in order to create a "neo-neck." An aortic balloon was inflated into the visceral aorta to avoid back bleeding. A Dacron bifurcated tube graft (Intergard, Maquet) was then sutured to the neo-neck mimicking endobanding, passing the stitches into the aortic wall and the first covered stent.

RESULTS

The mean age was 68 years (range, 52-84 years). The stent grafts removed were four Zenith (Cook Medical), three Endurant (Medtronic), and two E-vita (Jotec). The indication for conversion was type 1A (n = 2), type 2 (n = 2), and type 3 (n = 1) endoleak, complete endograft thrombosis (n = 2), and abdominal pain with sac enlargement with no radiological sign of endoleak (n = 2). Blood loss was 1,428 mL (range 500-3,000 mL); the visceral ischemic time to perform the proximal anastomosis was 23.5 min ± 2.3 min). The post-operative complication rate was 11% (n = 1/9) related to a case of sac wall bleeding requiring re-intervention; mortality at 30 days was 0%. At 22 months (range, 8-41) the computed tomography angiogram demonstrated no signs of leaks or anastomotic pseudoaneurysm.

CONCLUSION

Preservation of the proximal covered stent of an endograft with suprarenal fixation used as an infrarenal "neo-neck" with incorporation of the aorta to the suture line during elective surgical explantation simplifies the procedure, and can be achieved with very low early morbidity and mortality; furthermore, it seems to be durable over mid-term follow up.

Initial single-center experience with the Ovation stent-graft system in the treatment of abdominal aortic aneurysms: application to challenging iliac access anatomies

BACKGROUND

To present our preliminary results with the Ovation(™) abdominal stent-graft system in abdominal aortic aneurysms (AAA) with narrow (≤7 mm) or angulated iliac vessels.

METHODS

From April 2012 to January 2014, 42 patients (97% men; mean age, 71 years; range, 55-89 years) with AAAs of 55.5 mm (50-79 mm) were treated with the Ovation device. Primary end points included technical success and freedom from early secondary interventions, any type of endoleak, and aneurysm-related death. Limb occlusion was studied with respect to iliac access diameter and angulation. Iliac angulation between 90° and 120° or <90° was considered moderate or severe, respectively.

RESULTS

The postoperative follow-up was 7.8 ± 4.6 months (mean ± standard deviation). Infrarenal neck angulation was 26° ± 26°. AAA neck length and diameter were 27.3 ± 10.5 and 24.1 ± 3.2 mm, respectively. Forty-five percent of patients had at least 1 vessel of ≤7-mm diameter, and almost half of patients (24 of 44) had at least 1 iliac artery of moderate or severe angulation. Technical and treatment success were 100% and 95%, respectively. No stent-graft migration or type I, III, or IV endoleaks occurred. Type II endoleaks were identified in 5 patients, leading to sac enlargement in 2 and necessitating an embolization attempt that was unsuccessful in 1 case. No limb occlusion occurred, irrespective of the iliac diameter or angulation.

CONCLUSIONS

Our 1-year results of the Ovation stent-graft system demonstrate excellent safety and effectiveness. The easy navigation through highly angulated and stenosed iliac vessels ensures high technical success in cases of challenging iliac anatomy. Follow-up is ongoing.

Infective Etiology Affects Outcomes of Late Open Conversion After Failed Endovascular Aneurysm Repair

Purpose: To retrospectively review all patients undergoing late open conversion (LOC) after endovascular aneurysm repair (EVAR) in order to identify any clinical or technical predictors of poor outcome. Methods: Twenty-six consecutive patients (24 men; mean age 74.7±8.3 years) underwent LOC between June 2006 and April 2013 at our institution. The mean interval from index EVAR to LOC was 40.4±29.2 months (range 5–93 months). The indication for LOC was endoleak in 14 (54%) patients and infection in 12 (46%): 2 (8%) patients with endoleak had a ruptured aneurysm and 6 (23%) patients with infection had a recurrent secondary aortoesophageal fistula (sAEF). Results: In all 12 cases of infection and in 12 of 14 endoleaks, the entire endograft was explanted. A rifampin-soaked Dacron silver graft was implanted in all patients with infection. Patients with any infection and with recurrent AEF required more blood units than patients with endoleak (6.40 vs. 1.86, p=0.045; 6.76 vs. 1.86, p=0.0036, respectively). Compared with endoleak, the duration of conversions in the setting of infection (274 vs. 316 minutes, p=0.42) and recurrent sAEF (274 vs. 396 minutes, p=0.021) was longer. All patients with recurrent sAEF died at a mean 3.0±2.5 days after LOC from proximal anastomosis disruption and hemorrhagic shock (n=2), myocardial infarction (n=2), acute stroke (n=1), or persistent sepsis (n=1). Perioperative mortality was significantly higher in patients with endograft infection (6/12, p=0.002) and in cases of supraceliac cross-clamping (4/6, p=0.003). The association of infection with supraceliac cross-clamping was a strong predictor for perioperative mortality (p<0.001). Conclusion: In our experience, endograft infection led to greater perioperative mortality after LOC. Recurrent aortoenteric fistula in association with supraceliac cross-clamping is a strong predictor of poor outcome. Patients surviving the perioperative period may have good chances of long-term survival.

A new risk-scoring model for predicting 30-day mortality after repair of abdominal aortic aneurysms in the era of endovascular procedures

Purpose

To propose a new, multivariable risk-scoring model for predicting 30-day mortality in individuals underwent repair of abdominal aortic aneurysms (AAA).

Methods

Four hundred eighty-five consecutive patients who underwent AAA repair from January 2000 to December 2010 were included in the study. Univariate and multivariate analyses were performed to evaluate the risk factors, and a risk-scoring model was developed.

Results

Multivariate analysis identified three independent preoperative risk factors associated with mortality, and a risk-scoring model was created by assigning an equal value to each factor. The independent predictors were location of the AAA, rupture of AAA, and preoperative pulmonary dysfunction. The multivariable regression model demonstrated moderate discrimination (c statistic, 0.811) and calibration (Hosmer-Lemeshow test, P = 0.793). The observed mortality rate did not differ significantly from that predicted by our risk-scoring model.

Conclusion

Our risk-scoring model has excellent ability to predict 30-day mortality after AAA repair, and awaits validation in further studies.

Endovascular repositioning of a migrated stent graft using "endoanchor capture"

Endovascular aneurysm repair is increasingly used to treat patients harboring abdominal aortic aneurysms with severe comorbidities that make them unfavorable candidates for open repair. Graft-related complications in these patients also require unique solutions. We report the novel technique of "endoanchor capture" for successful repositioning of a migrated stent graft.

Clinical outcome of an extended proximal seal zone with the AFX endovascular aortic aneurysm system

OBJECTIVE

Despite improvements in endograft technology, operator skill, and patient selection, endovascular aneurysm repair continues to be associated with device-related complications. A retrospective, observational study was undertaken to evaluate the clinical outcome and imaging findings of a unique device having externally-mounted, conformable graft material.

METHODS

Infrarenal abdominal aortic aneurysms were treated with the Endologix, Inc AFX endovascular aortic aneurysm system (Irvine, Calif) endograft in 108 consecutive patients over a 25-month period at two U.S. clinical sites. Baseline characteristics and procedural outcomes were reviewed by independent monitors. Serial computed tomography (CT) imaging assessments were performed by an independent core laboratory. Aortic neck characteristics and graft apposition were analyzed from center line-reformatted CT data sets in 37 patients in an imaging cohort comprising subjects with high-resolution baseline and follow-up CT imaging for precise assessment of aortic neck characteristics. The mean follow-up was 11 ± 5 months overall, 9 ± 6 months in patients with core laboratory imaging, and 5 ± 2 months for patients in the imaging cohort.

RESULTS

Among the 108 patients, 103 (95%) had intact aneurysms and five (4.6%) were treated for rupture; 80 (74%) were male and 28 (26%) were female. On average, 2.3 ± 0.7 endograft components were implanted per patient and no adjunctive proximal neck bare stents were used. There were no perioperative deaths in patients with intact aneurysms; two patients who presented with ruptured aortic aneurysms (40%) died. Major adverse events occurred within 30 days of implantation in two patients (1.9%) with intact aneurysms. Type II endoleaks were evident on completion angiography in 18 patients (16.7%). Core laboratory analysis of CT studies identified two patients with type Ia endoleaks (2.3%), two with type III endoleaks (2.3%), and five with type II endoleaks (5.7%). Aneurysm-related secondary procedures were required in five patients over the first year of follow-up (4.6%). No patient developed endograft limb occlusion or aneurysm rupture and there were no open surgical conversions. In the imaging cohort, 360° graft-to-aortic wall apposition was continuous over a length of 25 ± 17 mm and extended the seal zone an average of 5 mm beyond the end of the anatomic neck. Early sac regression was correlated with neck length (P = .019) and graft-to-aortic apposition surface area (P = .039).

CONCLUSIONS

The real-world use of the AFX endograft was associated with a low rate of device-and procedure-related complications. The ability to achieve an extended seal zone beyond the anatomical neck might in part contribute to positive outcomes, including the low type Ia and type II endoleak rate. These findings suggest that the AFX device might offer some advantages over other currently marketed endografts, but confirmation awaits the availability of longer-term outcome data.

Abdominal aortic aneurysm repair: long-term follow-up of endovascular versus open repair

INTRODUCTION

To compare early and long-term outcomes of endovascular abdominal aortic aneurysm repair (EVAR) versus open repair (OPEN).

DESIGN

Prospective observational, per protocol, non-randomized, with retrospective analyses.

MATERIAL AND METHODS

Between 2000 and 2005, a total of 311 patients having EVAR or OPEN repair of infrarenal abdominal aortic aneurysms were identified and included in this prospective single-center observational study. A propensity score-based optimal-matching algorithm was employed, and 138 patients undergoing EVAR procedures were matched (1: 1) to OPEN repair.

RESULTS

Open repair showed higher hospital mortality (17% vs. 6%, p = 0.004), respiratory failure (p < 0.026), transfusion requirement (p < 0.001), and intensive care unit admission (27% vs. 7%, p < 0.001), and longer hospitalization (p < 0.001). Median follow-up was 70 months (25(th) to 75(th) percentile, 24 to 101). Actuarial survival estimates at 1, 5 and 10 years were 93%, 74%, 49% for the OPEN group compared to 89%, 69%, 59% for the EVAR group (p = 0.465). A significant difference between groups was observed in younger patients (< 75 years) only (p < 0.044). Late complication and re-intervention rates were significantly higher in EVAR patients (p < 0.001 and p = 0.002, respectively). Freedom from late complications at 1, 5 and 10 years was 96%, 92%, 86%, and 84%, 70%, 64% for OPEN and EVAR procedures, respectively.

CONCLUSIONS

Our experience confirms the excellent results of the EVAR procedures, offering excellent early and long-term results in terms of safety and reduction of mortality. Patients < 75 years seem to benefit from EVAR not only in the immediate postoperative period but even in a long-term perspective.

Type II endoleak after endovascular aneurysm repair

Background

The aim was to assess the risk of rupture, and determine the benefits of intervention for the treatment of type II endoleak after endovascular abdominal aortic aneurysm repair (EVAR).

Methods

This systematic review was done according to PRISMA guidelines. Outcome data included incidence, spontaneous resolution, sac expansion, interventions, clinical success, and complications including conversion to open repair, and rupture.

Results

Thirty-two non-randomized retrospective studies were included, totalling 21 744 patients who underwent EVAR. There were 1515 type II endoleaks and 393 interventions. Type II endoleak was seen in 10·2 per cent of patients after EVAR; 35·4 per cent resolved spontaneously. Fourteen patients (0·9 per cent) with isolated type II endoleak had ruptured abdominal aortic aneurysm; six of these did not have known aneurysm sac expansion. Of 393 interventions for type II endoleak, 28·5 per cent were unsuccessful. Translumbar embolization had a higher clinical success rate than transarterial embolization (81 versus 62·5 per cent respectively; P = 0·024) and fewer recurrent endoleaks were reported (19 versus 35·8 per cent; P = 0·036). Transarterial embolization also had a higher rate of complications (9·2 per cent versus none; P = 0·043).

Conclusion

Aortic aneurysm rupture after EVAR secondary to an isolated type II endoleak is rare (less than 1 per cent), but over a third occur in the absence of sac expansion. Translumbar embolization had a higher success rate with a lower risk of complications.

Stent graft types for endovascular repair of abdominal aortic aneurysms

BACKGROUND

The UK prevalence of abdominal aortic aneurysm (AAA) is estimated at 4.9% in over 65-year olds. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of AAAs involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of AAA.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched November 2012) and CENTRAL (2012, Issue 10). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of AAAs were sought without language restriction and in consultation with the Peripheral Vascular Disease Group TSC.

DATA COLLECTION AND ANALYSIS

We planned to conduct data collection and analysis in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. Therefore, this review cannot recommend guidance to clinicians in their selection of stent graft types. High quality randomised controlled trials evaluating stent graft types in abdominal endovascular aneurysm repair are required.

Stent graft types for endovascular repair of thoracic aortic aneurysms

BACKGROUND

The UK prevalence of thoracic aneurysm is estimated at 10.4 per 100,000 person-years. Progressive and unpredictable enlargement can lead to rupture. Endovascular repair of thoracic aortic aneurysms involves a stent graft system being introduced via the femoral artery and manipulated within the aorta under radiological guidance. Following endograft deployment, a seal is formed at the proximal and distal landing zones to exclude the aneurysm sac from the circulation. With the increasing popularity of endovascular repair there has been an increase in the number of commercially available stent graft designs on the market.

OBJECTIVES

This review aimed to assess the different stent graft types for endovascular repair of thoracic aortic aneurysms.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator (TSC) searched the Specialised Register (last searched November 2012) and CENTRAL (2012, Issue 11). Trial databases were searched by the TSC for details of ongoing and unpublished studies.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) of stent graft types in the repair of thoracic aortic aneurysms were sought without language restriction.

DATA COLLECTION AND ANALYSIS

Data collection and analysis was conducted in accordance with the Cochrane Handbook for Systematic Reviews of Interventions.

MAIN RESULTS

No studies were identified that met the inclusion criteria.

AUTHORS' CONCLUSIONS

Unfortunately, no data exist regarding direct comparisons of the performance of different stent graft types. Therefore, this review cannot recommend guidance to clinicians in their selection of stent graft types. High quality RCTs evaluating stent graft types in thoracic endovascular aneurysm repair are required.

APC resistance due to Factor V Leiden is not related to baseline inflammatory mediators or survival up to 10 years in patients with critical limb ischemia

To prospectively evaluate the potential influence of resistance to activated protein C (APC-resistance) on the initial inflammatory response, amputation rate and survival during 10 years of follow-up in patients with critical limb ischemia (CLI). Two hundred and fifty-six consecutive CLI patients were analyzed for APC-ratio, the Factor V Leiden mutation and inflammatory mediators and then prospectively followed for 10 years. Inflammatory mediators, amputation rate, morbidity and mortality were compared between patients with and without APC resistance. Of the 256 CLI patients, 35 (14 %) were heterozygotes and 2 (1 %) homozygotes for the Factor V gene mutation, whereas 219 (86 %) patients were non-APC resistant. No significant differences were found between APC resistant and non-APC resistant patients regarding inflammatory mediators. Non-APC resistant patients more often had infrainguinal atherosclerosis (172 [79 %] vs 22 [59 %]; p = 0.017). Amputation rate at 1 year did not differ. Furthermore, there were no significant differences between groups regarding 1-, 3-, 5-, or 10-year survival. APC resistance in patients with CLI was not related to inflammatory activity, and had no impact on limb salvage or rate of amputation or long-term mortality. APC-resistant CLI-patients less frequently had infrainguinal arteriosclerosis, however.

Endovascular abdominal aortic aneurysm repair: surveillance of endoleak using maximum transverse diameter of aorta on non-enhanced CT

BACKGROUND

Repeat volumetric analysis of abdominal aortic aneurysm (AAA) after endovascular AAA repair (EVAR) is time-consuming and requires advanced processing, dedicated equipment, and skilled operators.

PURPOSE

To clarify the validity of measuring the maximal short-axis diameter (Dmax) of AAA in follow-up non-enhanced axial CT as a means of detecting substantial endoleaks after EVAR.

MATERIAL AND METHODS

CT images were retrospectively reviewed in 47 patients (7 women, 40 men; mean age, 76.2 years) who had no endoleak on initial contrast-enhanced CT after EVAR. Regular follow-up CT studies were performed every 6 months. At each CT study, the Dmax on the CT axial image was measured and compared with that on the last CT (115 data-sets). Contrast-enhanced CT was regarded as the standard of reference to decide the presence or absence of endoleaks. The appearance of endoleak was defined as the end point of this study.

RESULTS

Endoleaks were detected in 17 patients during the follow-up period. Mean Dmax changes for 6 months were significant between positive and negative endoleak cases (1.8 ± 1.9 vs. -1.1 ± 3.0 mm, P < 0.0001). When the Dmax change ≤ 0 mm for 6 months was used as the threshold for negative endoleak, the sensitivity, specificity, positive predictive value, and negative predictive value were 74.5, 82.4, 96.1, and 35.9%, respectively. When Dmax change ≤-1 mm was used as the threshold, the sensitivity, specificity, PPV, and NPV were 38.8, 100, 100, and 22.1%, respectively.

CONCLUSION

Contrast-enhanced CT is not required for the evaluation of endoleaks when the Dmax decreases by at least 1 mm over 6 months after EVAR.

Correção endovascular do aneurisma da aorta abdominal: análise dos resultados de único centro

OBJETIVO: Avaliar os resultados clínicos imediatos e em médio prazo do tratamento endovascular em pacientes portadores de aneurisma da aorta abdominal em um centro de referência para doenças cardiovasculares. MATERIAIS E MÉTODOS: Estudo retrospectivo de uma série de pacientes submetidos a tratamento endovascular de aneurisma da aorta abdominal, no período de janeiro de 2009 a julho de 2010. Foram avaliados as características demográficas, o sucesso técnico, o sucesso terapêutico, a morbimortalidade, as complicações e a taxa de reintervenções perioperatórias imediatos, e após um ano de acompanhamento. RESULTADOS: Foram analisados 102 pacientes consecutivos com idade média de 72 ± 9 anos, sendo 79% deles do sexo masculino. Houve sucesso técnico em 97,1% e êxito terapêutico em 81% dos casos. A mortalidade perioperatória foi de 0,9% e a anual, de 7,8%. Foram necessárias reintervenções em 18,8% dos pacientes durante o seguimento. CONCLUSÃO: Em nosso estudo, os resultados obtidos justificam a realização desse procedimento nos pacientes com anatomia adequada.

Treatment of complications following endovascular repair of abdominal aortic aneurysms

Endovascular aneurysm repair (EVAR) is an important treatment option for abdominal aortic aneurysms, with lower perioperative morbidity and mortality rates than open surgical aneurysm repair. However, EVAR is associated with several unique complications that are not encountered with surgical repair such as endoleaks, graft migration, and renal artery occlusion. Preservation of the morbidity and mortality advantages of EVAR relies on the successful treatment of these complications by minimally invasive, endovascular approaches. Some of the techniques used to treat EVAR complications include balloon dilation and stenting, deployment of additional stent-graft pieces, coil embolization, and thrombolysis. Although the employment of these endovascular salvage techniques is common, data regarding their intermediate- to long-term efficacy is sparse, and further studies are needed to determine their efficacy in preventing conversion to open aneurysm repair and aneurysm rupture.

Conversion to open repair after endografting for abdominal aortic aneurysm: a review of causes, incidence, results, and surgical techniques of reconstruction

PURPOSE

To review the incidence, causes, and mortality rates of early and late conversion to open surgery after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA).

METHODS

A systematic search of the English-language literature from 2002 to 2009 was performed by interrogation of the PubMed, MEDLINE, and EMBASE databases. Studies were included if they: (1) had >100 patients treated with EVAR and (2) provided adequate data to calculate incidence and associated mortality rates. The search yielded 13 articles with sufficient data to analyze early conversion (12,236 patients, 178 conversions) and 15 articles with available data for late conversion (14,298 patients, 279 conversions).

RESULTS

The rate of early conversion among the 13 articles reviewed ranged from 0.8% to 5.9%; more recent studies carried lower rates of early conversion. Mortality rates of early conversion varied between 0% and 28.5%. Overall, there were 178 (1.5%) early conversions among the 12,236 AAAs treated with EVAR, with an average mortality of 12.4%. The rates of late conversion ranged from 0.4% to 22%. Of the 14,289 AAA patients undergoing endovascular repair, 279 (1.9%) required late conversion; the mortality rate was 10%.

CONCLUSION

Though the incidence is gradually declining, secondary interventions persist as the Achilles' heel of EVAR. A lifelong follow-up strategy for AAA patients treated with EVAR is essential for early detection and treatment of complications of the procedure. Vascular surgeons should be familiar with the complex open conversion procedures.

Evaluation of a new computerized analysis system developed for the processing of CT follow-up scans after EVR of infrarenal aneurysm

PURPOSE

The aim of this retrospective study was to present a new computerized analysis system developed for the evaluation of follow-up CT scans after endovascular repair (EVR) of infrarenal aneurysm and to compare it to the conventional evaluation method as regards preciseness and ease of application. The system is based on the extraction of the surface of the stent-graft (SG) and that of the spinal canal and the overlay of surfaces obtained at different points in time.

MATERIALS AND METHODS

A total of 116 CT follow-up data sets obtained from 49 patients after EVR of infrarenal aneurysm were evaluated using both, the conventional method and the new computerized system. Two parameters were analyzed: SG length and the distance between the most ventral point of the SG and the vertebral column. The correlation between the results of the two methods and the correlation between the results obtained by two independent observers (radiologist and lay person) using the new system were assessed by statistical analysis.

RESULTS

Comparison of the two methods yielded a very high correlation for both parameters, (correlation coefficients of around 0.9 and p<0.001). Comparison of the results obtained by the two observers yielded an equally high correlation (correlation coefficients of around 0.9 and p<0.001).

CONCLUSION

Our results show that the new computerized system is as precise and reliable as the conventional method, but allows better visualization and quantification of SG changes by surface overlay. Moreover, it is easier to apply and less time-consuming and can be easily integrated into existing systems.

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

PURPOSE

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

METHOD

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

RESULTS

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

CONCLUSION

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