Suprarenal Abdominal Aortic Aneurysm Research Articles

Risk Factors of Postoperative Intestinal Ischemia After Abdominal Aortic Aneurysm Repair

Introduction - Intestinal ischemia remains a complication following abdominal aortic aneurysm (AAA) repair associated with a high mortality.1-6 The influence of possible risk factors for developing postoperative intestinal ischemia needs clarification. We sought to define predictors as well as the related mortality and to form a prediction model with the predictiors found. Methods - A nationwide population-based cohort study of 9433 patients who underwent an AAA operation between 2014 and 2016 was conducted. Potential risk factors were determined by reviewing prior studies and univariate analysis. With logistic regression analysis independent predictors of intestinal ischemia were established. These variables were used to form a prediction model. Results - Intestinal ischemia occurred in 267 patients (2.8%). Rupture of AAA was the most important predictor of developing intestinal ischemia (odds ratio [OR], 5.9, 95% confidence interval [CI]4.4-8.0), followed by having a suprarenal AAA (OR 3.4; CI 1.1-10.6). Associated procedural factors were open repair (OR 2.8; 95%CI 1.9-4.2), blood loss >1L (OR 3.6; 95%CI 1.7-7.5) and prolonged operating time (OR 2.0; 95%CI 1.4-2.8). Patient characteristics included having peripheral arterial disease (OR 2.4; 95%CI 1.3-4.4), female gender (OR 1.7; 95%CI 1.2-2.4), renal insufficiency (OR 1.7; 1.3-2.2) and pulmonary history (OR 1.6; 95%CI 1.2-2.2). Age <68 proved to be a protective factor (OR 0.5; 95%CI 0.4-0.8). Associated mortality was higher in patients with intestinal ischemia versus patients without (50.6% vs 5.1%, p<.001). A prediction model with an excellent AUC=0.878 (95% CI 0.860-0.896) could be formed. Conclusion - The prediction model can be used to identify patients at high risk for developing intestinal ischemia and possibly lower the mortality risk.

Juxtarenal Aortic Aneurysm: Are We Ready for a Randomised Trial on Open versus Endovascular Repair?

In the last two decades, advances in endovascular aneurysm repair (EVAR) technology have led to the introduction of fenestrated (fEVAR) and branched (bEVAR) stent grafts for the treatment of juxta- and suprarenal abdominal aortic aneurysms (JRAAAs and SRAAAs), extending the proximal sealing zone from the infrarenal to the suprarenal aorta and expanding the EVAR indications to complex abdominal aortic aneurysms (AAAs).

Infrarenal versus Suprarenal Abdominal Aortic Aneurysms: Comparison of Associated Aneurysms and Renal Artery Stenosis

The aim of our study is to assess the prevalence of concomitant arterial abnormalities (true aneurysms of iliac, common femoral, renal, visceral arteries and stenoses of iliac and renal arteries) in patients with abdominal aortic aneurysm, and to evaluate whether the type of the aneurysm (suprarenal versus solely infrarenal) is associated with this prevalence. In this retrospective cross-sectional study, we assessed computed tomography angiography scans of 933 patients with abdominal aortic aneurysm, including thoracoabdominal aortic aneurysms type II-IV, with no history of abdominal aortic surgery. We compared 2 groups of patients: group 1 (n=859) with solely infrarenal abdominal aortic aneurysm and group 2 (n=74) with the suprarenal aneurysm component. Patients with history of aortic dissection or thoracoabdominal aortic aneurysms type I and V were excluded from the study. All computed tomography angiography scans were visually assessed by 2 independent experienced physicians. Study group comprised 933 patients with the median age of 73.0years, 83.8% of whom were male. We observed higher prevalence of common iliac artery aneurysms (44.6% vs. 30.6%, P=0.013), internal iliac artery aneurysms (28.4% vs. 18.0%, P=0.03), common femoral artery aneurysms (13.5% vs. 4.4%, P<0.001), visceral artery aneurysms (5.4% vs. 1.2%, P=0.019), renal artery stenosis (20.3% vs. 5.2%, P<0.001), renal atrophy (6.7% vs. 1.1%, P=0.004), and severe chronic kidney disease (14.1% vs. 1.8%, P<0.001) in group 2 compared to group 1. There were no significant differences in the prevalence of iliac arterial stenoses between the groups. Among patients with abdominal aortic aneurysm, concomitant aneurysms and renal artery stenosis are more common in patients with suprarenal component when compared to those with solely infrarenal presentation.

Early results of endovascular aneurysm sealing with chimney grafts to treat juxtarenal and suprarenal abdominal aortic aneurysms

BackgroundThe treatment of juxtarenal abdominal aortic aneurysms is challenging. Open surgical repair is not a viable option for many patients. The use of endovascular aneurysm sealing (EVAS) with chimney grafts (Ch-EVAS) has been proposed as an immediately available, off-the-shelf option for individuals with juxtarenal aneurysms who require urgent treatment or are unsuitable for fenestrated or branched devices. This study reports the outcomes from our first patients to undergo this procedure. MethodsData were collected prospectively for 62 consecutive patients undergoing Ch-EVAS at our institution. The procedures were undertaken for intact juxtarenal or suprarenal aneurysms in patients who were unfit for open repair or needed urgent treatment or when the aneurysm morphology was unsuitable for treatment with fenestrated or branched endografts. ResultsBetween July 2013 and June 2016, there were 62 patients who were treated with Ch-EVAS; 77.4% were male, and the mean age was 73.9 years. Median aneurysm diameter was 64.5 mm. Eight suprarenal aneurysms were treated, with three chimney grafts. Of 54 juxtarenal aneurysms treated, 21 cases used two chimney grafts and 33 cases used one chimney graft. Median follow-up was 407 days. Eleven patients underwent reintervention. There were five type IA endoleaks, all successfully treated. One type IB and one type II endoleak occurred, neither requiring treatment. There were four minor strokes. Chimney patency is 97%. ConclusionsThese results in a group of high-risk patients suggest that Ch-EVAS is a viable alternative to custom-made devices in patients who are unfit for open surgery. Longer term follow-up and data from the international registry will determine the widespread applicability and durability of this technique.

Fenestrated endovascular aneurysm repair is associated with lower perioperative morbidity and mortality compared with open repair for complex abdominal aortic aneurysms

ObjectiveThe Zenith Fenestrated Endovascular Graft (ZFEN; Cook Medical, Bloomington, Ind) has expanded the anatomic eligibility of endovascular aneurysm repair (EVAR) for complex abdominal aortic aneurysms (AAAs). Current data on ZFEN mainly consist of single-institution experiences and show conflicting results. Therefore, we compared perioperative outcomes after repair using ZFEN with open complex AAA repair and infrarenal EVAR in a nationwide multicenter registry. MethodsWe identified all patients undergoing elective AAA repair using ZFEN, open complex AAA repair, and standard infrarenal EVAR between 2012 and 2016 within the American College of Surgeons National Surgical Quality Improvement Program targeted vascular module. Open complex AAA repairs were defined as those with a juxtarenal or suprarenal proximal AAA extent in combination with an aortic cross-clamping position that was above at least one renal artery. The primary outcome was perioperative mortality, defined as death within 30 days or within the index hospitalization. Secondary outcomes included postoperative renal dysfunction (creatinine concentration increase of >2 mg/dL from preoperative value or new dialysis), occurrence of any complication, procedure times, blood transfusion rates, and length of stay. To account for baseline differences, we calculated propensity scores and employed inverse probability-weighted logistic regression. ResultsWe identified 6825 AAA repairs—220 ZFENs, 181 open complex AAA repairs, and 6424 infrarenal EVARs. Univariate analysis of ZFEN compared with open complex AAA repair demonstrated lower rates of perioperative mortality (1.8% vs 8.8%; P = .001), postoperative renal dysfunction (1.4% vs 7.7%; P = .002), and overall complications (11% vs 33%; P < .001). In addition, fewer patients undergoing ZFEN received blood transfusions (22% vs 73%; P < .001), and median length of stay was shorter (2 vs 7 days; P < .001). After adjustment, open complex AAA repair was associated with higher odds of perioperative mortality (odds ratio [OR], 4.9; 95% confidence interval [CI], 1.4-18), postoperative renal dysfunction (OR, 13; 95% CI, 3.6-49), and overall complication rates (OR, 4.2; 95% CI, 2.3-7.5) compared with ZFEN. Compared with infrarenal EVAR, ZFEN presented comparable rates of perioperative mortality (1.8% vs 0.8%; P = .084), renal dysfunction (1.4% vs 0.7%; P = .19), and any complication (11% vs 7.7%; P = .09). Furthermore, after adjustment, there was no significant difference between the odds of perioperative mortality, postoperative renal dysfunction, or any complication between infrarenal EVAR and ZFEN. ConclusionsZFEN is associated with lower perioperative morbidity and mortality compared with open complex AAA repair, and outcomes are comparable to those of infrarenal EVAR. Long-term durability of ZFEN compared with open complex AAA repair warrants future research.

Fenestrated and Chimney Endovascular vs Open Repair of Juxtarenal, Pararenal, and Suprarenal Abdominal Aortic Aneurysms: 5-Year National Study (2012 to 2016)

Locham, Satinderjit S. MD; Aridi, Hanaa Dakour MD; Bhela, Jatminderpal MD; Nejim, Besma MBChB, MPH; Challa, Apurva B. MD; Malas, Mahmoud MD, MHS, FACS Author Information

IP071. Comparison of Fenestrated Endovascular and Open Surgical Repair for Suprarenal and Type IV Thoracoabdominal Aortic Aneurysms∗

The aim of this monocentric retrospective study was to compare outcomes of fenestrated endovascular aneurysm repair (FEVAR) and open surgical repair (OR) of suprarenal abdominal aortic aneurysms and type IV thoracoabdominal aneurysms (TAAAs). Consecutive patients undergoing elective FEVAR and OR of suprarenal and type IV TAAAs between January 2012 and November 2015 were included. Choice between FEVAR and OR was based on anatomic criteria and the patient’s comorbidities. In the OR group, an extracorporeal circulation was systematically used to provide oxygenated isothermic blood to the renal and the visceral arteries during aortic clamping. During the study period, 26 patients underwent FEVAR and 26 underwent OR. Patients in the FEVAR group were significantly older (FEVAR, 74 ± 8 years; OR, 67 ± 8 years; P < .001) and had a lower preoperative glomerular filtration rate (FEVAR, 63 [47-81] mL/min/1.73 m2; OR, 77 [64-87] mL/min/1.73 m2; P = .049). Univariate analysis showed no difference in terms of 30-day mortality (FEVAR and OR groups, 2/26 [7.7%]). Moderate to severe complication rates were 54% (14/26) in the FEVAR group and 65% (17/26; P = .4) in the OR group. Permanent paraplegia occurred in one (4%) FEVAR patient and two (8%) OR patients. In the FEVAR group, two (8%) patients required permanent dialysis. In the OR group, four (15%) patients required transient dialysis. The mean follow-up time was 37 ± 20 months after FEVAR and 35 ± 18 months after OR. At 24 months, the actuarial survival rate was significantly higher in the OR group (FEVAR group, 62%; OR group, 92%; log-rank test, P = .03), and estimated freedom from reintervention rates (FEVAR vs OR group, 64% vs 64%; log-rank test, P = .63) were not significantly different between both groups. In this study, no significant difference in terms of postoperative mortality, complication, and reintervention rates could be identified between FEVAR and OR for suprarenal and type IV TAAAs. OR provided good midterm results.

Fenestrated and Branched Endografts

Multiple clinical trials have established the safety and efficacy of endovascular aortic aneurysm repair, which has resulted in a major paradigm shift from open to endovascular repair for the treatment of most aortic aneurysms. However, juxtarenal aneurysms (JRAAs) and more complex aneurysms involving the visceral aorta pose a significant challenge to the goals of fixation and seal using standard infrarenal devices. The need for branch vessel preservation and the individual variability of their origins from the aorta add significant complexity to the design, manufacturing, and implantation of endovascular grafts. To address these limitations, fenestrated and branched endografts have been developed that allow fixation and seal above the renal or visceral vessels but maintain perfusion to these branches by aligning fenestrations in the endograft fabric to the origins of these vessels or, in the case of thoracoabdominal aneurysms, providing branches. This review discusses fenestrated and branched endografts, as well as their complications and outcomes. Figures show definitions and examples of complex abdominal aortic aneurysm (AAA), features of the Zenith Fenestrated AAA Endovascular Graft, and features of the Cook Zenith P-branch device, an off-the-shelf fenestrated device under investigation for endovascular repair of JRAA. Tables list Zenith Fenestrated AAA Endovascular Graft indications for use and device components, graft and vessel-sized diameters for fenestrated devices, accessories for fenestrated endovascular repair, and results of reports dealing with fenestrated and branched endografts for juxtarenal and suprarenal AAA. This review contains 12 highly rendered figures, 5 tables, and 53 references. Key words: abdominal aortic aneurysm, branched endograft, complex abdominal aortic aneurysm, endovascular aortic aneurysm repair, fenestrated endograft, juxtarenal aneurysms, suprarenal abdominal aortic aneurysm

Computational modelling of abdominal aortic aneurysms: Effect of suprarenal vs infrarenal positions

Abdominal aortic aneurysms (AAA) are seen in both suprarenal and infrarenal positions though infrarenal is more common. Initiation and development of thrombosis and atherosclerosis in abdominal aneurysms and renal arteries have previously been correlated to areas of adverse haemodynamic conditions such as flow recirculation, low shear stress and high temporal oscillation in shear. However, it is still unknown if the haemodynamic perturbations arisen from different types of aneurysms, suprarenal vs infrarenal, contribute to the formation of atherosclerosis within the renal branches. In this work, virtual models of symmetric and asymmetric AAAs located above and below renal branches were simulated under resting and exercise conditions to determine the influence of location of the aneurysm on important haemodynamic parameters. The results showed that the size of the recirculation zones and vortices inside the renal branches and aneurysm region is considerably smaller in the infrarenal AAAs than the suprarenal models. Furthermore, our data demonstrated that occurrence of the aneurysm below the renal level augments the magnitude of shear stress and reduces the oscillations in shear in renal branches. These results confirm that the suprarenal AAA promotes thrombosis initiation within the aneurysm and increases the risk of endothelial dysfunction and the development of atherosclerosis in renal arteries. The findings also showed that under exercise conditions the haemodynamic differences between the suprarenal and infrarenal AAAs become less important and the local unfavourable haemodynamic conditions are improved to some extent.

An optimized retroperitoneal approach for open aortic repair by partially removing the tenth rib without incising the pleura and diaphragm

The ninth intercostal thoracoretroperitoneal incision is the most common approach for open repair of suprarenal abdominal aortic aneurysm or abdominal aortic dissection, which necessitates incision of the pleura and diaphragm and may lead to cardiorespiratory distress postoperatively. We optimized this approach by partially removing the tenth rib, bluntly dissecting the diaphragm from its costal edge, and retracting the diaphragm superiorly. We successfully performed this approach in three patients with pararenal abdominal aortic aneurysm, abdominal aortic dissection, or renal artery aneurysm. Based on our experience, this approach allows easy exposure of the suprarenal aorta and avoids thoracotomy, which would potentially benefit patients' prognosis.

Abstract 106: Characterizing Aortic Wall Dynamics in Murine Models of Abdominal Aortic Aneurysms Using Ultrasound Imaging

The objective of this study is to use non-invasive ultrasound imaging to characterize aortic wall dynamics in abdominal aortic aneurysms (AAAs). We induced AAAs (n=5) in apolipoprotein-E deficient mice by subcutaneously implanting an osmotic pump, which systemically delivers angiotensin II at a rate of 1000 ng/kg/min for 28 days, in the back of each mouse. Once aneurysm formations were confirmed using a high frequency small animal ultrasound system (Vevo2100, Visualsonics; 40 MHz central frequency), we implemented our cardiac- and respiratory-gated volumetric ultrasound technique to acquire 3D AAA geometries throughout a cardiac cycle. Figure 1 summarizes the results obtained from a representative mouse with a suprarenal AAA. A 3D volume rendering of an abdominal aorta, with the aneurysm positioned in the center, is illustrated next to a color bar, which provides position references for both the maximum circumferential Green-Lagrangian (GL) strain and the instantaneous strain plots. Qualitative inspections of both strain plots depicted in Figure 1 demonstrate that maximum GL circumferential strain occurs during systole and is smallest within the AAA. Quantitative assessments of GL circumferential strain for all five AAAs were performed with similar results indicating that maximum GL strain decreased significantly within the aneurysm (1.1±0.2%) compared to proximal (9.3±5.3%) and distal (4.0±2.1%) regions (p&lt;0.05). This decrease in GL circumferential strain within the aneurysmal portion of the abdominal aorta corroborates the idea that an increase in vessel stiffness is associated with the degradation of elastin and increased collagen turnover in the AAA wall. Interestingly, in all five cases, we observed a stiffer distal region, when compared to regions proximal to the aneurysm, suggesting that AAA development may also contribute to extracellular matrix remodeling of the aortic wall downstream of the aneurysm site.

Contemporary outcomes of open complex abdominal aortic aneurysm repair

The recent commercial availability of fenestrated stent grafts is likely to result in increasing endovascular repair of complex (juxtarenal and suprarenal) abdominal aortic aneurysms (cAAAs). Whereas most studies providing benchmarking for outcomes after open repair have been from high-volume centers, we sought to evaluate outcomes after elective open cAAA repair vs infrarenal AAA repair at a regional level. We used the Vascular Study Group of New England registry, which recorded 1875 open AAA repairs in New England from 2003 to 2011. Data from 14 hospitals performing both AAA and cAAA repair were used to assess the impact of clinical and technical factors on outcomes of cAAA repair. There were 443 patients who had elective cAAA repair as defined by use of a suprarenal (n= 340; 77%) or supraceliac (n= 103; 23%) clamp, with median survival follow-up of 35months (interquartile range, 47months). Compared with AAA repair, patients undergoing cAAA repair were more likely to be female; to have hypertension, congestive heart failure, or chronic obstructive pulmonary disease; and to have a higher baseline creatinine concentration. cAAA cases were repaired through a retroperitoneal incision in 40% of cases, with hypothermic renal perfusion use in 15%, mannitol in 73%, and renal bypass in 13%, with wide variability in the application of these adjuncts. Complex aneurysm repair vs routine AAA repair was associated with a higher independent risk of 30-day mortality (3.6% vs 1.2%; P= .002), respiratory complications (19% vs 10%; P< .001), and renal complications (21% vs 8.7%; P< .001). Among all patients, the only independent clinical or technical predictors of 30-day mortality were preoperative coronary artery disease (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.1-5.4; P= .02) and amount of intraoperative blood transfusion (OR,2.8; 95% CI, 1.3-6.2; P= .01). In the subgroup undergoing cAAA repair, there were no predictors of operative mortality. Renal or visceral ischemia time was the only technical factor during cAAA repair that independently predicted cardiac (OR, 1.01; 95% CI, 1.00-1.03; P= .04), respiratory (OR, 1.03; 95% CI, 1.01-1.04; P< .001), and renal (OR,1.03; 95% CI, 1.02-1.05; P< .001) complications. Long-term survival for cAAA patients was 91%± 1% at 1year and 71%± 3% at 5years and not different from that of patients undergoing infrarenal AAA repair. Risk-adjusted predictors of late mortality after cAAA repair included age (hazard ratio [HR], 1.08; 95% CI, 1.04-1.11; P< .001), chronic obstructive pulmonary disease (HR, 1.9; 95% CI, 1.2-3.0; P= .008), and preoperative creatinine concentration (per mg/dL; HR, 1.8; 95% CI, 1.05-2.9; P= .03). These data highlight excellent operative outcomes for open cAAA repair across the New England region despite significant variation in operative conduct across hospitals. Patients tolerating cAAA repair have durable long-term survival.

Spinal cord ischemia after endovascular repair of thoracoabdominal aortic aneurysms with fenestrated and branched stent grafts

The aim of this study was to report the incidence and associated risk factors of perioperative spinal cord ischemia (SCI) after endovascular repair of thoracoabdominal aortic aneurysms (TAAAs) with fenestrated and branched stent grafts. The study included consecutive patients with TAAA treated with fenestrated and branched stent grafts within the period January 2004 to December 2014. Suprarenal abdominal aortic aneurysms treated with fenestrated and branched grafts, even if including all four visceral vessels, were excluded. Patients who died within 30 days after the procedure were excluded from the analysis for SCI. All data were collected prospectively. A total of 218 patients (167 men; mean age, 68.8 ± 7.5 years) were treated. Thirty-day mortality was 17 patients (7.8%). TAAA distribution among the 201 surviving patients was as follows: type I, n = 17 (8.5%); type II, n = 55 (27.4%); type III, n = 63 (31.3%); type IV, n = 54 (26.9%); and type V, n = 12 (5.9%). In the surviving patients, 21 (10.4%) developed perioperative SCI. At 30 days postoperatively, 13 (6.5%) of those patients had transient lower limb weakness, 5 patients (2.5%) had persistent lower limb weakness requiring assistance to stand or to walk, and 3 patients (1.5%) had persistent paraplegia. Five of the 21 patients awoke from anesthesia with a neurologic deficit. The remaining 16 patients had a later postoperative onset of SCI, with the majority of them (14 of 16) within 72 hours after the operation. Multivariate analysis using logistic regression identified operation time >300 minutes (odds ratio [OR], 7.4; 95% confidence interval [CI], 2.6-21.1; P < .001), peripheral arterial disease (OR, 6.6; 95% CI, 2-21.9; P = .002), and baseline renal insufficiency (glomerular filtration rate <30 mL/min; OR, 4.1; 95% CI, 1.1-16.1; P = .04) as independent risk factors for SCI. In our experience, most SCI events after endovascular TAAA repair are transient, with persistent paraplegia being rare. Patients with prolonged procedure duration, peripheral arterial disease, and baseline renal insufficiency appear to be at higher risk for development of SCI after endovascular TAAA repair.

Comparative Effectiveness of Endovascular versus Open Repair for Juxta- and Suprarenal Abdominal Aortic Aneurysms

Comparative Effectiveness of Endovascular versus Open Repair for Juxta- and Suprarenal Abdominal Aortic Aneurysms

Troubleshooting techniques for the Endurant™ device in endovascular aortic aneurysm repair.

Endovascular aortic aneurysm repair with the EndurantTM stent-graft system has been shown to be safe and effective in high-risk surgical patients with complex suprarenal and/or infrarenal abdominal aortic aneurysm anatomy. The wireformed M-shaped stent architecture and proximal springs with anchoring pins theoretically permit optimal sealing in shorter and more angulated proximal aneurysm necks even under off-label conditions. Nonetheless, extremely difficult anatomical situations and inherent graft system-related limitations must be anticipated. Herein, we describe our techniques to overcome the capture of the tip sleeve within the suprarenal bare-stent anchoring pins, other endograft segments, and native vessels.

Inadequate reinforcement of transmedial disruptions at branch points subtends aortic aneurysm formation in apolipoprotein-E-deficient mice

Infusion of angiotensin-II (Ang-II) in apolipoprotein-E-deficient mice (Apo-E(-/-)) results in suprarenal abdominal aortic aneurysm (AAA) in 30-85% of cases. This study identifies the apparent mechanism by which some animals do, but others do not, develop AAA in this model. Male Apo-E(-/-) mice were infused with Ang-II (n=21) or saline (n=6) and sacrificed at 4 weeks. Aortas were excised, embedded in paraffin, sectioned (250 μm intervals), and stained. Sites of transmedial disruption (TMD) were identified and characterized, and their relationship to the 4 major aortic side branches (celiac, superior mesenteric, and renals) were determined. The frequency of TMDs in Ang-II-infused mice that formed AAA (n=9) was similar to those that did not (n=12) (AAA vs. no-AAA: 25 of 36[69%] vs. 28 of 48[58%] branches, P=.3 by chi-square). All TMDs were at branch points. However, in animals with AAA, the mean maximum length of the TMDs was significantly larger (1.94±1.6 vs. 0.65±0.5mm, P=.007 by Mann Whitney U test), the #mac-2(+) macrophages per 0.01mm(2) of defect area was greater (32±10 vs. 19±11, P<.02 by Kruskal-Wallis with Conover-Inman post hoc), the % area of attempted repair occupied by collagen was less (17±13% vs. 44±15%, P=.0009 by Mann Whitney U test), and the density of collagen per unit length of media missing was also markedly less (0.13±0.2 vs. 1.14±1.0, P=.0001 by Mann Whitney U test). Reinforcement of transmedial defects at branch points by wall matrix is a key intrinsic player in limiting AAA formation in the Ang-II-infused, Apo E(-/-) mouse and a potentially important mechanism-based therapeutic target for management of small, slowly progressing aneurysms.

The fate of untreated concomitant suprarenal aortic aneurysms after endovascular aneurysm repair of infrarenal aortic aneurysms

Many patients treated with endovascular aortic repair (EVAR) have a concomitant suprarenal abdominal aortic aneurysm (sAAA). The natural history of these sAAAs and whether they require intervention after EVAR is unknown. We identified 470 patients from the M2S database (M2S Inc, West Lebanon, NH) as having an infrarenal AAA (iAAA) with a concomitant sAAA (diameter, 2.9-4.7 cm). The analysis included 217 patients with preoperative computed tomography angiography and follow-up imaging of ≥12 months. Patients who did not undergo EVAR (n = 65) served as a control. Patients with EVAR were subdivided into 90 with suprarenal fixation (SR) and 62 with infrarenal fixation (IR). Standard measurements from the M2S images were extracted, and growth rates were calculated for different abdominal aortic segments. The average follow-up was 33.0 ± 18.8 months. The average sAAA initial size and growth rate were 34.6 ± 3.0 and 0.6 ± 1.1 mm/y for SR, 34.0 ± 3.3 and 0.6 ± 1.3 mm/y for IR, and 36.6 ± 3.4 and 1.2 ± 1.5 mm/y for controls (SR vs IR, P > .05; SR or IR vs control, P < .05). After EVAR, two of 152 (1.3%) sAAAs grew to ≥ 50 mm, which was not statistically different from four of 65 (6.2%) in the control group (P = .07). At 48 months, the Kaplan-Meier freedom from sAAA growth to ≥ 50 mm was 99.3% for patients undergoing EVAR and 95.2% for controls (P = .061). Patients with starting sAAAs sized ≥ 40 mm had a higher growth rate (1.4 ± 2.1 mm/y) and frequency of growth to ≥50 mm (14.3%) than patients with starting sAAAs sized <40 mm (0.7 ± 1.2 mm/y and 1.5%; P < .05). Isolated treatment of iAAAs via EVAR with a concomitant sAAA is acceptable because endografts with or without SR do not affect sAAA growth rates. Routine EVAR follow-up is sufficient for sAAAs of <40 mm, and more intensive follow-up should be considered for sAAAs of 40 to 50 mm. For sAAAs approaching 50 mm, an endograft with IR should be considered in case sAAA repair is required in the future.

When the chimney is blocked: malignant renovascular hypertension after endovascular repair of abdominal aortic aneurysm

BackgroundThe Chimney graft (CG) procedure is one of the novel modification techniques of the endovascular aneurysm repair (EVAR) surgery to treat suprarenal and juxtarenal abdominal aortic aneurysms. Other indications for the use of CG placement include thoracic and thoracoabdominal aneurysms with supraortic branches orifice involvement and cases of common iliac artery aneurysms with or without internal iliac artery involvement. The technique is used in patients who due to aortic-neck morphology and lack of adequate fixation and/or sealing zones are not eligible for standard EVAR. In this procedure, a parallel stent-graft is placed adjacent to the main body of the aortic endograft to maintain blood supply to renovisceral or supraortic branches, once the body of the aortic stent-graft is deployed. Symptomatic occlusions of the CG with novel renovascular hypertension were not described until now.Case presentationA-64-year-old male patient, presented with new-onset malignant hypertension, 13 months after an EVAR operation with CG placement to the left renal artery. The patient was on preventive clopidrogel therapy, which was withheld temporarily for several days, one month before presentation. Imaging studies revealed a novel form of iatrogenic renovascular hypertension, caused by occlusion of the CG. Any attempt to recanalize the covered stent or revascularize the left kidney was rejected and conservative treatment was chosen. Seven months after presentation, blood pressure was within normal ranges with little need for antihypertensive therapy.ConclusionsPhysicians should be aware that the novel emerging techniques of EVAR to overcome the limitations of the aortic-neck anatomy may still adversely influence the renal outcome with potential development of new-onset hypertension.

An Unusual Cause of Duodenal Obstruction

Introduction Superior mesenteric artery (SMA) compression of the duodenum is well described, but duodenal obstruction caused by extrinsic compression from an abdominal aortic aneurysm (AAA) occurs rarely. Report This case report describes a patient who presented with nausea and bilious vomiting and was found to have SMA syndrome due to an 8.6 cm suprarenal AAA. He declined an open aneurysm repair, but elected to have an enteric bypass procedure for symptomatic relief. Discussion SMA syndrome is caused by compression of the third portion of the duodenum between the aorta and the SMA, resulting in complete or partial duodenal obstruction. Only 22 cases of SMA syndrome caused by an AAA have been reported in the literature; usually there is an inflammatory process involved with the aneurysm or there is an infrarenal aortic neck. Definitive treatment consists of open aneurysm repair or decompress the aneurysm sac; other options are enteric bypass, duodenal transposition or duodenal mobilization and caudal displacement (Strong's procedure).

Doxycycline Does Not Influence Established Abdominal Aortic Aneurysms in Angiotensin II-Infused Mice

BackgroundThere is no proven medical approach to attenuating expansion and rupture of abdominal aortic aneurysms (AAAs). One approach that is currently being investigated is the use of doxycycline. Despite being primarily used as an antimicrobial drug, doxycycline has been proposed to function in reducing AAA expansion. Doxycycline is effective in reducing the formation in the most commonly used mouse models of AAAs when administered prior to the initiation of the disease. The purpose of the current study was to determine the effects of doxycycline on established AAAs when it was administered at a dose that produces therapeutic serum concentrations.Methods and ResultsLDL receptor −/− male mice fed a saturated-fat supplemented diet were infused with AngII (1,000 ng/kg/min) via mini-osmotic pumps for 28 days. Upon verification of AAA formation by noninvasive high frequency ultrasonography, mice were stratified based on aortic lumen diameters, and continuously infused with AngII while also administered either vehicle or doxycycline (100 mg/kg/day) in drinking water for 56 days. Administration of doxycycline led to serum drug concentrations of 2.3±0.6 µg/ml. Doxycycline administration had no effect on serum cholesterol concentrations and systolic blood pressures. Doxycycline administration did not prevent progressive aortic dilation as determined by temporal measurements of lumen dimensions using high frequency ultrasound. This lack of effect on AAA regression and progression was confirmed at the termination of the study by ex vivo measurements of maximal width of suprarenal aortas and AAA volumes. Also, doxycycline did not reduce AAA rupture. Medial and adventitial remodeling was not overtly changed by doxycycline as determined by immunostaining and histological staining.ConclusionsDoxycycline administration did not influence AngII-induced AAA progression and aortic rupture when administered to mice with established AAAs.