Aortic aneurysm size and graft behavior after endovascular stent-grafting: clinical experiences and observations over 3 years

Escalation of Antithrombotic Therapy Should Be Considered in the Presence of Intraluminal Prosthetic Graft Thrombus Following Endovascular Aneurysm Repair

Objectives

Intraluminal prosthetic graft thrombus (IPT) following Endovascular Aneurysm Repair (EVAR) can have serious consequences. The aim of this study was to assess the prevalence of IPT and to identify the risk factors for its formation and progression.

Methods

This was a retrospective study of 258 patients who had EVAR between 2015 and 2018. Demographic data, comorbidities, operative data, antithrombotic therapy, CT anatomical data, IPT characteristics (site, regression, and progression), and re-interventions were collected. Univariable analysis followed by multivariable logistic regression and Cox regression were used for data analysis.

Results

The mean age of patients was 76 years (range 55-95) and 27 (10.5 %) were females. IPT was present in 26 patients (10.1%) with a median time to occurrence of six (range 1- - 24) months. Of the group that developed IPT, six (23.1 %) developed symptoms and two (7.7%) had re-interventions. Multivariable logistic regression analysis revealed peripheral arterial disease to be associated with the formation of IPT (OR 7.4, 95% CI 1.6-35.3, p = 0.02) and escalation of antithrombotic therapy was associated with regression or prevention of progression of IPT (OR 0.1, 95% CI 0.0-0.6, p = 0.01).

Conclusion

PAD is associated with the formation of IPT after EVAR and warrants consideration of escalation of antithrombotic therapy to prevent further progression and complications.

Contrast-enhanced ultrasound and/or colour duplex ultrasound for surveillance after endovascular abdominal aortic aneurysm repair: a systematic review and economic evaluation

BACKGROUND

Endovascular abdominal aortic aneurysm repair (EVAR) of abdominal aortic aneurysm (AAA) is less invasive than open surgery, but may be associated with important complications. Patients receiving EVAR require long-term surveillance to detect abnormalities and direct treatments. Computed tomography angiography (CTA) has been the most common imaging modality adopted for EVAR surveillance, but it is associated with repeated radiation exposure and the risk of contrast-related nephropathy. Colour duplex ultrasound (CDU) and, more recently, contrast-enhanced ultrasound (CEU) have been suggested as possible, safer, alternatives to CTA.

OBJECTIVES

To assess the clinical effectiveness and cost-effectiveness of imaging strategies, using either CDU or CEU alone or in conjunction with plain radiography, compared with CTA for EVAR surveillance.

DATA SOURCES

Major electronic databases were searched, including MEDLINE, EMBASE, Science Citation Index, Scopus' Articles-in-Press, Cochrane Central Register of Controlled Trials (CENTRAL), Database of Abstracts of Reviews of Effects (DARE) and NHS Economic Evaluation Database from 1996 onwards. We also searched for relevant ongoing studies and conference proceedings. The final searches were undertaken in September 2016.

METHODS

We conducted a systematic review of randomised controlled trials and cohort studies of patients with AAAs who were receiving surveillance using CTA, CDU and CEU with or without plain radiography. Three reviewers were involved in the study selection, data extraction and risk-of-bias assessment. We developed a Markov model based on five surveillance strategies: (1) annual CTA; (2) annual CDU; (3) annual CEU; (4) CDU together with CTA at 1 year, followed by CDU on an annual basis; and (5) CEU together with CTA at 1 year, followed by CEU on an annual basis. All of these strategies also considered plain radiography on an annual basis.

RESULTS

We identified two non-randomised comparative studies and 25 cohort studies of interventions, and nine systematic reviews of diagnostic accuracy. Overall, the proportion of patients who required reintervention ranged from 1.1% (mean follow-up of 24 months) to 23.8% (mean follow-up of 32 months). Reintervention was mainly required for patients with thrombosis and types I-III endoleaks. All-cause mortality ranged from 2.7% (mean follow-up of 24 months) to 42% (mean follow-up of 54.8 months). Aneurysm-related mortality occurred in < 1% of the participants. Strategies based on early and mid-term CTA and/or CDU and long-term CDU surveillance were broadly comparable with those based on a combination of CTA and CDU throughout the follow-up period in terms of clinical complications, reinterventions and mortality. The economic evaluation showed that a CDU-based strategy generated lower expected costs and higher quality-adjusted life-year (QALYs) than a CTA-based strategy and has a 63% probability of being cost-effective at a £30,000 willingness-to-pay-per-QALY threshold. A CEU-based strategy generated more QALYs, but at higher costs, and became cost-effective only for high-risk patient groups.

LIMITATIONS

Most studies were rated as being at a high or moderate risk of bias. No studies compared CDU with CEU. Substantial clinical heterogeneity precluded a formal synthesis of results. The economic model was hindered by a lack of suitable data.

CONCLUSIONS

Current surveillance practice is very heterogeneous. CDU may be a safe and cost-effective alternative to CTA, with CTA being reserved for abnormal/inconclusive CDU cases.

FUTURE WORK

Research is needed to validate the safety of modified, more-targeted surveillance protocols based on the use of CDU and CEU. The role of radiography for surveillance after EVAR requires clarification.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016036475.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Significance and Risk Factors for Intraprosthetic Mural Thrombus in Abdominal Aortic Endografts: A Systematic Review and Meta-analysis

BACKGROUND

The detection of intraprosthetic thrombus (IPT) deposits is a common finding during follow-up for endovascular abdominal aneurysm repair (EVAR); however, its clinical significance is still debated. The aim of this study was to determine if IPT represents a risk factor for thromboembolic events (TEs; endograft or limb thrombosis, or distal embolization) after EVAR.

METHODS

A systematic review of English literature was undertaken until November 2017. Studies providing 2-group comparison (patients with IPT development on postoperative computed tomography angiography versus patients without IPT) with extractable outcome data (TE related to IPT and/or risk factors for IPT development) were included. Meta-analysis was performed when comparative data were given in 2 or more articles.

RESULTS

Five single-center studies (808 patients) were analyzed. IPT detection at any time during follow-up occurred in 20.8% (168/808) of patients. Extractable data for postoperative TE were available in 4 studies (613 patients): on comparative meta-analysis, IPT was not significantly associated with TE occurrence during follow-up (odds ratio 2.25, 95% confidence interval [CI] 0.50-10.1; P = 0.29). IPT is generally detected during the first year after EVAR (maximum reported median: 12 months, range: 1.2-23). Polyester graft material (odds ratio 2.34, 95% CI 1.53-3.58; P < 0.001) and aorto-uni-iliac configuration of the endograft (odds ratio 3.27, 95% CI 1.66-6.44; P = 0.001) were confirmed as risk factors for IPT formation on meta-analysis. The literature systematic review suggests that IPT formation may be also associated with long main bodies and large necks.

CONCLUSIONS

IPT detection on postoperative computed tomography angiography was not significantly associated with the occurrence of TE over time. The aorto-uni-iliac configuration and the use of polyester fabric for endografts were confirmed as risk factors for IPT development.

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.

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.

Secondary interventions following endovascular abdominal aortic aneurysm repair using current endografts. A EUROSTAR report

OBJECTIVE

The purpose of this study was to evaluate the need for secondary interventions after endovascular abdominal aortic aneurysm repair with current stent-grafts.

METHODS

Studied were data from 2846 patients treated from December 1999 until December 2004. The data were recorded from the EUROSTAR registry. The only patients studied were those with a follow-up of at least 12 months or until they had a secondary intervention within the first 12 months. The cumulative incidences of secondary transabdominal, extra-anatomic, and transfemoral interventions during follow-up (after the first postoperative month) were investigated.

RESULTS

A secondary intervention was performed in 247 patients (8.7%) at a mean of 12 months after the initial procedure within a follow-up period of a mean of 23 +/- 12 months. Of these, 57 (23%) transabdominal, 43 (16%) involved an extra-anatomic bypass, and 147 (60%) were by transfemoral approach. The cumulative incidence of secondary interventions was 6.0%, 8.7%, 12%, and 14% at 1, 2, 3, and 4 years, respectively. This corresponded with an annual rate of secondary interventions of 4.6%, which was remarkably lower than in a previously published EUROSTAR study of patients treated before 1999. Type I endoleaks (33% of procedures), migration (16%), and rupture (8.8%) were the most frequent reasons for secondary transabdominal interventions. Graft limb thrombosis was the indication for extra-anatomic bypass (60%). Type I endoleak (17%), type II endoleak (23%), device limb stenosis (14%), thrombosis (23%), and device migration (14%) were the most frequent reasons for secondary transfemoral interventions. Operative mortality was higher after secondary transabdominal interventions (12.3%, P = .007) compared with transfemoral interventions (2.7%). Overall survival was lower in patients with secondary transabdominal (P = .016) and extra-anatomic interventions (P < .0001) compared with patients without a secondary intervention.

CONCLUSION

Although the incidence of secondary interventions after endovascular aneurysm repair has substantially decreased in recent years, continuing need for surveillance for device-related complications remains necessary.

Factors affecting the regression of surgically replaced abdominal aortic aneurysms

PURPOSE

After endovascular therapy for abdominal aortic aneurysms, aneurysm sac shrinkage is considered to be the best marker of successful treatment. Such shrinkage, however, is infrequent and the rate of shrinkage is variable because of endoleaks. To investigate the factors that influence such contraction, the aneurysm sac regression after a conventional surgical replacement of the abdominal aortic aneurysm in an inclusion fashion was studied.

METHODS

Abdominal aortic aneurysms that measured 5 cm in diameter or larger were studied in 35 patients who underwent surgical replacement. The aneurysm sac was closed anterior to the prosthesis. Of the 35 cases, 4 aneurysms were inflammatory and 10 had aneurysm wall circumferential calcification of greater than 40%. Computed tomography was performed preoperatively, and at 1 week, and then 3 months postoperatively.

RESULTS

The maximum major and minor diameters of the aneurysmal sac decreased significantly from 1 week to 3 months after surgery (major diameter: 49 +/- 12 to 32 +/- 8 mm and minor diameter: 39 +/- 10 to 26 +/- 7 mm). In inflammatory aneurysms, the maximum major and minor diameters were significantly larger at 3 months postoperatively, in comparison to nonspecific aneurysms. Among the 31 patients with nonspecific aneurysms, the maximum major diameter was significantly larger in those with aneurysmal calcification of greater than 40% of its circumference at 3 months postoperatively, in comparison to noncalcified aneurysms.

CONCLUSIONS

The surgically repaired abdominal aortic aneurysm contraction tends to develop over 3 months, and inflammation, thickening, and calcification of the aneurysm wall are all considered to influence the regression of the aneurysm.

Six-Year Experience With Talent Stent-Graft Repair of Abdominal Aortic Aneurysms

PURPOSE

To report a long-term experience with the Talent Endoprosthesis for the treatment of abdominal aortic aneurysm (AAA).

METHODS

In the period between June 1997 and June 2003, 193 patients (171 men; mean age 71.0+/-7.8 years, range 52-89) with AAA were treated with a Talent Endoprosthesis. Patients were clinically and radiologically followed in the postoperative period, at 30 days, and then annually up to 72 months. In addition to computed tomographic scans, a plain abdominal radiogram was also performed annually for structural assessment of the stent-graft.

RESULTS

Implantation success was 99.0% (191/193). Delivery system introduction was the cause of 1 failure, and the other patient was converted to surgery for intraprocedural device migration. There were 10 (5.2%) endoleaks (3 type I, 7 type II) at 30 days; all type I and 3/7 type II endoleaks were treated (93.3% secondary clinical success). Seven (3.7%) patients died in the perioperative period, including the conversion. During follow-up, 18 (9.3%) additional deaths occurred, and 4 new endoleaks (1 type I, 2 type II, 1 type III) were encountered. In up to 6 years' follow-up, the Talent Endoprosthesis did not present signs of material fatigue, but 1 component disconnection at 42 months led to death. There was no aneurysm rupture. After an initial increase in the aortic neck (1.2+/-1.1 mm) in the postoperative period, the neck diameters continued to increase until after the third year. An average reduction of 5.6+/-4.1 mm in the aneurysm diameter at 1 year was noted; the reduction gradually reached 14.1+/-10.7 mm after 60 months.

CONCLUSIONS

The Talent Endoprosthesis was an efficient alternative for managing AAAs, achieving low morbidity and mortality rates and a good long-term clinical outcome in this study. The Talent Endoprosthesis did not present signs of material fatigue over a 6-year follow-up.

Abdominal aortic aneurysm size regression after endovascular repair is endograft dependent

OBJECTIVE

This study was performed to determine whether abdominal aortic aneurysm (AAA) regression is different with various endografts after endovascular repair.

METHODS

A four-center retrospective review of size change after endovascular AAA repair was performed. Consecutive patients with at least 1-year follow-up and available imaging studies were included. Three hundred ninety patients received either the Ancure, AneuRx, Excluder, or Talent endograft. AAA size and endoleak status were recorded from computed tomography (CT) scans at the initial postoperative follow-up visit and at 1 and 2 years thereafter. AAA size was defined as the minor axis of the infrarenal aorta on the largest axial section on the two-dimensional CT scan. A change in AAA size of 0.5 cm or greater from baseline was considered clinically significant. The effect of initial size, endoleak, and type of endograft on AAA regression was analyzed.

RESULTS

Mean baseline size was significantly greater with Talent endografts and smaller with Excluder endografts. Clinically significant regression in AAA size occurred in nearly three fourths of patients with Ancure and Talent endografts at 2 years. Regression in AAA size was less frequent with the AneuRx (46%) and Excluder (44%) devices. Initial size, endoleak, and endograft type were significant predictors of regression at multivariate analysis at 1 year. However, by 2 years only endograft type was still an independent predictor of AAA shrinkage.

CONCLUSIONS

Long-term morphologic changes after endovascular aneurysm repair depend on endograft type.

Contrast-enhanced ultrasound imaging for aortic stent-graft surveillance

PURPOSE

To compare unenhanced and enhanced ultrasound imaging to computed tomographic angiography (CTA) or magnetic resonance angiography (MRA) for surveillance of aortic endografts.

METHODS

Thirty consecutive patients (29 men; mean age 69 years, range 50-82) who underwent endovascular aortic aneurysm repair agreed to participate in a follow-up program. Patients underwent CTA (26/30) or MRA (4/30), plain abdominal radiography, and unenhanced and enhanced ultrasound examinations at 3, 12, and 24 months to evaluate aneurysm diameter, endoleaks, and graft patency. The accuracy of ultrasound was compared with CTA or MRA as the reference standards.

RESULTS

Twenty-six patients reached the 24-month assessment (mean follow-up 30 months, range 6-60). All endoleaks detected by CTA or MRA were confirmed by enhanced ultrasound; the aneurysm diameter in these patients remained unchanged or increased. In patients without endoleaks on any imaging method, the sac diameter remained unchanged or decreased. Endoleaks disclosed by enhanced ultrasound alone, all type II, numbered 16 at 3 months, 6 at 12 months, and 3 at 24 months. In this group, the aneurysm diameter remained unchanged or increased. Enhanced ultrasound yielded 100% sensitivity in detecting endoleaks, but compared with CTA and MRA, all endoleaks detected by enhanced ultrasound alone were false positives (mean specificity 65%). Nevertheless, because changes in the postoperative aneurysm diameter were similar in patients with endoleaks detectable on CTA/MRA and on enhanced ultrasound ("true positives") and in those with endoleaks detectable only on enhanced ultrasound ("false positives"), some endoleaks were possibly "true positive" results.

CONCLUSIONS

Enhanced ultrasound is a useful method in the long-term surveillance of endovascular aortic aneurysm repairs, possibly in association with CTA or MRA. Enhanced ultrasound also seems able to identify endoleaks missed by other imaging techniques, but this conclusion awaits further investigation.

Endotension distribution and the role of thrombus following endovascular AAA exclusion

PURPOSE

To determine the pattern of strain and pressure transmitted to an aortic aneurysm wall before and after endovascular exclusion and to evaluate the role of sac thrombus on the conduction of pressure and wall strain.

METHODS

Three canine thoracic aortas were used to create abdominal aortic aneurysms (AAA). The segments were placed on a pulsatile pump system, and 8 strain transducers were positioned in the aneurysm sac. Baseline strain/pressure (S/P) was recorded in 1 animal, then the AAA was excluded with a stent-graft. Thrombin was injected into the sac, and strain/pressure was recorded at 7 systemic pressures (35 to 120 mmHg) over 6 hours. The thrombus was replaced with fibrin glue, and S/P was recorded over 4 hours. Additional trials using whole and 50% diluted unclotted blood were performed prior to sac thrombosis. Computed tomography and angiography were performed before and after aneurysm exclusion.

RESULTS

Pressure transmitted to the aneurysm wall decreased following stent-graft placement (p<or=0.001). Strain/pressure was not distributed evenly in the sac (p<or=0.05), and varying systemic pressures did not affect this distribution. Pressures near the stent-graft were higher than those laterally (p<or=0.001) in all trials with interposed fresh thrombus and fibrin thrombus. The fibrin group had elevated baseline measurements, but correction for the elevated values did not influence the statistical significance (p<or=0.001). Blood and fibrin thrombus reduced transmitted wall pressure to a similar degree. Overall S/P in the fluid-filled nonclotted sac was significantly lower (p<or=0.001) than in the thrombus groups.

CONCLUSIONS

Endovascular AAA exclusion reduced strain and pressure conducted to the aneurysm wall, and the distribution of transmitted pressure in the excluded sac without endoleak differed regardless of the sac contents. Fresh thrombus reduced transmittedS/P in all trials at all systemic pressures, as did fibrin thrombus but in a less predictable fashion.

Potential impact of therapeutic warfarin treatment on type II endoleaks and sac shrinkage rates on midterm follow-up examination

OBJECTIVE

Successful endovascular aortic aneurysm repair depends on exclusion and spontaneous thrombosis of the aneurysm sac. The need for chronic postoperative anticoagulation therapy could limit the applicability of this technology with delay or prevention of sac thrombosis resulting in endoleak formation and altered remodeling of the aneurysm sac. The purpose of this study was the determination of whether chronic therapeutic anticoagulation therapy with warfarin was associated with an increased incidence rate of early or delayed postoperative endoleaks or altered rates of reduction in aneurysm sac maximum diameter.

METHODS

Two hundred thirty-two consecutive patients underwent abdominal aortic endografting during a 32-month period. The data were recorded prospectively with a current mean follow-up period of 18 months. The patients with endoleaks identified with 30-day postoperative computed tomographic scan angiograms subsequently underwent selective arteriography to characterize the source. The patients who underwent chronic warfarin therapy that resulted in a therapeutic internationalized normalized ratio comprised the study group. The control group was defined as all the patients with healthy coagulation profiles.

RESULTS

Thirty-six patients (15%) were undergoing warfarin therapy after surgery, and their conditions were chronically maintained with a therapeutic international normalized ratio. Forty-three patients (18%) had endoleaks on 30-day computed tomographic scan angiographic results. There were 39 patients with type II endoleaks and four patients with type I endoleaks. None of the type I endoleaks occurred in patients who were undergoing warfarin therapy, and all endoleaks were repaired with either proximal or distal covered extensions. At 30 days, seven patients (19.4%) undergoing chronic warfarin therapy had type II endoleaks as compared with 36 controls (18.4%; P =.798). Four patients had delayed type II endoleaks develop, two in the control group and two in the warfarin group (P =.3). Ten control individuals (31%) had spontaneous resolution of type II endoleaks develop, whereas spontaneous endoleak thrombosis was not observed in the warfarin group (P =.33). Aneurysm sac remodeling assessed with mean percent reduction in maximum sac diameter at 12 months revealed a statistical difference between the control group (17.5%) and the warfarin group (7.6%; P =.04).

CONCLUSION

Warfarin treatment is not associated with an increase in the incidence rate of early or delayed postoperative endoleaks. However, the rate of reduction in maximum aneurysm sac diameter after aortic endografting is slower in patients who undergo therapeutic warfarin therapy at 1-year follow-up examination, a statistically significant difference from the control group. In addition, type II endoleaks may be less likely to undergo spontaneous thrombosis in patients who undergo warfarin therapy.

Noninvasive diagnosis of incomplete endovascular aneurysm repair: D-dimer assay to detect type I endoleaks and nonshrinking aneurysms

PURPOSE

To test the hypothesis that D-dimer (D-D), a cross-linked fibrin degradation product of an ongoing thrombotic event, could be a marker for incomplete aneurysm exclusion after endovascular abdominal aortic aneurysm (AAA) repair.

METHODS

In a multicenter study, 83 venous blood samples were collected from 74 AAA endograft patients and controls. Twenty subjects who were >6 months postimplantation and had evidence of an endoleak and/or an unmodified or increasing AAA sac diameter formed the test group. Controls were 10 nondiseased subjects >65 years old, 18 AAA surgical candidates, and 26 postoperative endograft patients with no endoleak and a shrinking aneurysm. Blood samples were analyzed for D-D through a latex turbidimetric immunoassay. The endograft patients were stratified into 5 clinical groups for analysis: no endoleak and decreasing sac diameter, no endoleak and increasing/unchanged sac diameter, type II endoleak and decreasing sac diameter, type II endoleak and increasing/unchanged sac diameter, and type I endoleak.

RESULTS

Individual D-D values were highly variable, but differences among clinical groups were statistically significant (p < 0.0001). D-D values did not vary significantly between patients with stable, untreated AAAs and age-matched controls (238 +/- 180 ng/mL versus 421 +/- 400 ng/mL, p > 0.05). Median D-D values increased at 4 days postoperatively (963 ng/mL versus 382 ng/mL, p > 0.05) and did not vary thereafter if there was no endoleak and the aneurysm sac decreased. D-D mean values were higher in patients with type I endoleak (1931 +/- 924 ng/mL, p < 0.005) and those with unchanged/increasing sac diameters (1272 +/- 728 ng/mL) than in cases with decreasing diameters (median 638 +/- 238 ng/mL) despite the presence of endoleak (p < 0.0005).

CONCLUSIONS

Elevated D-D may prove to be a useful marker for fixation problems after endovascular AAA repair and may help rule out type I endoleak, thus excluding patients from unnecessary invasive tests.

Endoluminal stent grafts in the management of infrarenal abdominal aortic aneurysms: a realistic assessment

OBJECTIVES

transfemoral endoluminal aortic management (TEAM) is technically feasible in the treatment of infrarenal abdominal aortic aneurysms but its advantage over conventional repair is unproved. We report our initial experience, learning curve and technical difficulties encountered during the process of establishing this novel technique in our institute.

MATERIAL AND METHODS

over a 3-year period 400 cases of abdominal aortic aneurysms were reviewed; only 58 cases (15%) were suitable for endovascular repair under our TEAM protocol and 36 (9%) were offered endovascular intervention. They were mainly high-risk patients (85% ASA III and IV) with a mean age of 72 years. Thirty-three bifurcated grafts, two straight tube grafts and one aorto mono-iliac graft were deployed. We oversized the graft by 15-20% to the diameter of the aortic neck and both common iliac arteries.

RESULTS

two cases (6%-95% CI: 1-19%) had on-table conversion because of ruptured common iliac arteries. Peri-operatively there were two deaths from multi-organ failure. Transient renal failure occurred in two patients and three patients (9%) suffered a non-fatal myocardial infarction. Sixteen percent of patients had a groin wound problem. The mean hospital stay was 7 days. Five minor endoleaks (15%) were identified and sealed at 30 days. One secondary endoleak was identified at 18 months because of a patent juxta-renal lumbar artery. No secondary cuffs or extensions were used. Mean follow-up was 29 months and all grafts remained patent. The technical, clinical, continuous and secondary success rates were 78%, 91%, 89% and 91% respectively with TEAM.

CONCLUSION

endovascular training, patient selection and learning curve impose an impact on the final outcome. Until a reliable hard point is reached so that endovascular repair could be exercised in routine practice, the use of TEAM must be questioned in high-risk patients, and should be performed under clinical trial conditions using strict selection criteria.