Aortic Length Research Articles

One-year outcomes from an international study of the Ovation Abdominal Stent Graft System for endovascular aneurysm repair

This study evaluated 1-year safety and effectiveness outcomes of the United States regulatory trial for the Ovation Abdominal Stent Graft System (TriVascular Inc, Santa Rosa, Calif) for endovascular repair of abdominal aortic aneurysms (AAAs). This prospective, multicenter, single-arm trial was conducted at 36 sites in the United States, Germany, and Chile to evaluate the safety and effectiveness of the Ovation stent graft. From November 2009 to May 2011, 161 patients (88% males; mean age, 73 ± 8 years) with AAAs (mean diameter, 54 ± 9 mm) were treated with the Ovation stent graft. The main body is a modular two-docking limb device with a 14F outer diameter delivery system, active suprarenal fixation, and polymer-filled proximal rings that accommodate the aortic neck for seal. Main inclusion criteria included proximal aortic neck length ≥ 7 mm, inner neck diameter between 16 and 30 mm, distal iliac landing zones length ≥ 10 mm, and diameter between 8 and 20 mm. Patients were treated under a common protocol, including clinical and imaging follow-up at discharge, 30 days, 6 months, and annually through 5 years. A Clinical Events Committee adjudicated adverse events, an independent imaging core laboratory analyzed imaging, and a Data Safety and Monitoring Board provided study oversight. Complete 1-year follow-up data were available for this report. The Ovation stent graft was implanted successfully in 161 patients (100%), including 69 (42.9%) by percutaneous access. General anesthesia was used in 106 patients (65.8%). Technical success was 100%, and mean procedure time was 110 minutes. Median procedural blood loss was 150 mL, and median hospital stay was 1 day. The 30-day major adverse event rate was 2.5%. At 1 year, AAA-related and all-cause mortality were 0.6% and 2.5%, respectively. Major adverse event and serious adverse event rates through 1 year were 6.2% and 38.5%, respectively. The 1-year treatment success rate was 99.3%. The imaging core laboratory reported no stent graft migration or type I, III, or IV endoleaks. At 1 year, type II endoleaks were identified in 34% of patients, and AAA enlargement was identified in one patient (0.7%). No AAA rupture or conversion to open surgery was reported. AAA-related secondary procedures were performed in 10 patients (6.2%) for 12 findings, including endoleak (six), aortic main body stenosis (three), and iliac limb stenosis or occlusion (three). The 1-year results of the Ovation Abdominal Stent Graft System demonstrate excellent safety and effectiveness in treatment of patients with AAAs, particularly in patients with challenging anatomic characteristics, including short aortic necks and narrow iliac arteries. Longer-term follow-up is needed.

Late Aortic Remodeling Persists in the Stented Segment After Endovascular Repair of Acute Complicated Type B Aortic Dissection

Thoracic endovascular aortic repair (TEVAR) for acute complicated type B dissection (cTBD) promotes early positive aortic remodeling. However, little is known about the long-term effect of TEVAR on the dissected aorta, which is the goal of this study. Between August 2005 and August 2009, 31 patients with cTBD were treated with TEVAR and had long-term (>1 year) follow-up imaging. CTA obtained at 1 month (1M), 1 year (1Y), and long-term (LT; average 42 months) were compared with baseline (BL) scans. The largest diameters of the stented thoracic aorta (SMAX), stented true lumen (STL), and stented false lumen (SFL) were recorded at each time point, as were the values in the unstented distal thoracic aorta and the abdominal aorta. Changes over time were evaluated using a mixed effect analysis of variance model of repeated measures. Demographics: age 56 years; 74% male. Indications for TEVAR: 61% malperfusion, 32% refractory hypertension, 45% impending rupture, 32% persistent pain; 58% had >one indication. The average length of aorta covered was 19 cm. Aortic remodeling along the stented segment is summarized in Fig 1. The SMAX remained stable (P = not significant), STL increased (P < .001), and SFL decreased (P < .001) over time; 84% had complete false lumen (FL) obliteration. For the uncovered segment, the maximum diameter increased (P = .014), as did TL (P < .001) and the visceral segment (P < .001). The FL was stable (P = not significant). The average growth of the visceral segment was 31% in patients with a patent FL vs 3% in those without (P = .004). One patient had aneurysmal degeneration of the false lumen and required an additional endograft at 2 years. TEVAR of cTBD promotes long-term remodeling across the stented segment with FL obliteration in 84% of patients. However, FL obliteration beyond the stented segment appears necessary to prevent late aneurysmal degeneration.

Morphometric analysis of torso arterial anatomy with implications for resuscitative aortic occlusion

Hemorrhage is a leading cause of death in military and civilian trauma. Despite the importance of the aorta as a site of hemorrhage control and resuscitative occlusion, detailed knowledge of its morphometry is lacking. The objective of this study was to characterize aortic morphometry in a trauma population, including quantification of distances as well as and diameters and definition of relevant aortic zones. Center line measures were made (Volume Viewer) from contrast computed tomography (CT) scans of male trauma patients (18-45 years). Aortic zones were defined based on branch arteries. Zone I includes left subclavian to celiac; Zone II includes celiac to caudal renal; Zone III includes caudal renal to aortic bifurcation. Zone lengths were calculated and correlated to a novel external measure of torso extent (symphysis pubis to sternal notch). Eighty-eight males (mean [SD], 28 [4] years) had CT scans for the study. The median (interquartile range) lengths (mm) of Zones I, II, and III were 210 mm (202-223 mm), 33 mm (28-38 mm), and 97 mm (91-103 mm), respectively. Median aortic diameters at the left subclavian, celiac, and lowest renal arteries were 21 mm (20-23 mm), 18 mm (16-19 mm), and 15 mm (14-16 mm), respectively, and the terminal aortic diameter was 14 mm (13-15 mm). The correlation of determination for descending aortic length (all zones) against torso extend was r = 0.454. This study provides a morphometric analysis of the aorta in a male population, demonstrating consistency of length and diameter while defining distinct axial zones. Findings suggest that center line aortic distances correlate with a simple, external measure of torso extent. Morphometric study of the aorta using CT data may facilitate the development and implementation of occlusion techniques to manage noncompressible torso, pelvic, and junctional femoral hemorrhage.

Biomarkers of acute kidney injury in pediatric cardiac surgery

ObjectivesAcute kidney injury (AKI) is a significant problem in children undergoing cardiopulmonary bypass (CPB). The aims of this study were to assess the diagnostic validity of serum CysC (sCysC), serum neutrophil gelatinase lipocalin (sNGAL), urine neutrophil gelatinase lipocalin (uNGAL), urine kidney injury molecule (uKIM)-1, and urine liver fatty acid-binding protein (uL-FABP) to predict AKI presence and severity in children undergoing CPB. Design and methodsWe performed a prospective single-center evaluation of sCysC, sNGAL, uNGAL, uKIM-1 and uL-FABP at 0, 2, 6, 24 and 48h postoperatively in children undergoing CPB during cardiac surgery. AKI was defined as ≥25% decrease in the estimated creatinine clearance (eCCl) from pre-operative baseline at 48h after surgery. ResultsOf the 112 patients, 18 patients (16.1%) developed AKI; four of them needed acute dialysis treatment and three AKI patients died. In the AKI compared to the non-AKI group, sCysC at 2h, and uNGAL and uL-FABP at 2–48h were significantly increased, as well as CPB, aortic cross clamp time and length of hospital stay. Biomarkers increased with worsening AKI severity. At 2h after CPB the best accuracy for diagnosis of AKI had uL-FABP and sCysC with area under the receiver operator curve (AUC) of 0.89 and 0.73, respectively. At 6 and 24h after CPB the best AUC was found for uL-FABP (0.75 and 0.87 respectively) and for uNGAL (0.70 and 0.93, respectively). ConclusionssCysC, uNGAL and uL-FABP are reliable early predictors for AKI after CPB. By allowing earlier timing of injury and earlier intervention, they could improve AKI outcome.

A New Murine Model of Endovascular Aortic Aneurysm Repair

Endovascular aneurysm exclusion is a validated technique to prevent aneurysm rupture. Long-term results highlight technique limitations and new aspects of Abdominal aortic aneurysm (AAA) pathophysiology. There is no abdominal aortic aneurysm endograft exclusion model cheap and reproducible, which would allow deep investigations of AAA before and after treatment. We hereby describe how to induce, and then to exclude with a covered coronary stentgraft an abdominal aortic aneurysm in a rat. The well known elastase induced AAA model was first reported in 19901 in a rat, then described in mice2. Elastin degradation leads to dilation of the aorta with inflammatory infiltration of the abdominal wall and intra luminal thrombus, matching with human AAA. Endovascular exclusion with small covered stentgraft is then performed, excluding any interactions between circulating blood and the aneurysm thrombus. Appropriate exclusion and stentgraft patency is confirmed before euthanasia by an angiography thought the left carotid artery. Partial control of elastase diffusion makes aneurysm shape different for each animal. It is difficult to create an aneurysm, which will allow an appropriate length of aorta below the aneurysm for an easy stentgraft introduction, and with adequate proximal and distal neck to prevent endoleaks. Lots of failure can result to stentgraft introduction which sometimes lead to aorta tear with pain and troubles to stitch it, and endothelial damage with post op aorta thrombosis. Giving aspirin to rats before stentgraft implantation decreases failure rate without major hemorrhage. Clamping time activates neutrophils, endothelium and platelets, and may interfere with biological analysis.

A New Murine Model of Endovascular Aortic Aneurysm Repair

Endovascular aneurysm exclusion is a validated technique to prevent aneurysm rupture. Long-term results highlight technique limitations and new aspects of Abdominal aortic aneurysm (AAA) pathophysiology. There is no abdominal aortic aneurysm endograft exclusion model cheap and reproducible, which would allow deep investigations of AAA before and after treatment. We hereby describe how to induce, and then to exclude with a covered coronary stentgraft an abdominal aortic aneurysm in a rat. The well known elastase induced AAA model was first reported in 1990(1) in a rat, then described in mice(2). Elastin degradation leads to dilation of the aorta with inflammatory infiltration of the abdominal wall and intra luminal thrombus, matching with human AAA. Endovascular exclusion with small covered stentgraft is then performed, excluding any interactions between circulating blood and the aneurysm thrombus. Appropriate exclusion and stentgraft patency is confirmed before euthanasia by an angiography thought the left carotid artery. Partial control of elastase diffusion makes aneurysm shape different for each animal. It is difficult to create an aneurysm, which will allow an appropriate length of aorta below the aneurysm for an easy stentgraft introduction, and with adequate proximal and distal neck to prevent endoleaks. Lots of failure can result to stentgraft introduction which sometimes lead to aorta tear with pain and troubles to stitch it, and endothelial damage with post op aorta thrombosis. Giving aspirin to rats before stentgraft implantation decreases failure rate without major hemorrhage. Clamping time activates neutrophils, endothelium and platelets, and may interfere with biological analysis.

Centerline is Not as Accurate as Outer Curvature Length to Estimate Thoracic Endograft Length

To assess the accuracy of the aortic outer curvature length for thoracic endograft planning. Seventy-four patients (58 men, 66.4 ± 14 years) who underwent thoracic endovascular aortic repair between 2009 and 2011 treated with a Cook Medical endograft were enrolled in this retrospective study. Immediate postoperative CT scans were analysed using EndoSize software. Three vessel lengths were computed between two fixed landmarks placed at each end of the endograft: the straightline (axial) length, the centerline length and the outer curvature length. A tortuosity index was defined as the ratio of the centerline length/straightline length. A Student t test and a Pearson correlation coefficient were used to examine the results. We found a significant difference between the centerline length (135.4 ± 24 mm) and that of the endograft (160 ± 29 mm) (P < .0001). This difference correlates with the tortuosity index (r = .818, P < .0001), the endograft length (r = .587, P < .0001), and the diameter of the endograft (r = .53, P < .0001). However, the outer curvature length (161.3 ± 29 mm) and the endograft length (160 ± 29 mm) were similar (P = .792). The outer curvature length more accurately reflects that of the deployed endograft and may prove more accurate than centerlines in planning thoracic endografts.

Mechanism to Valve a Cabrol Fistula for Bleeding Control.

A circular aortic stapler has been developed to anastomose the open end of the aorta to a size-matched Dacron tube graft in one quick motion and without having to pull sutures through the aortic wall. A prototype was developed, and its design and function were tested in bench experiments and compared with hand-sewn anastomosis. The basic design of the stapler is a central rod (anvil) surrounded by 10 stapling limbs, which can be closed over the anvil in a full circle, with staples extruded by turning a knob at the back. To test its function, a Dacron tube graft was inserted in the middle of a length of bovine aorta. One side was anastomosed with the stapler and the other hand-sewn in each of 10 experiments. Bovine blood was infused under increasing pressure. It took considerably less time to complete the stapled anastomosis than the hand-sewn side (3 minutes, 46 seconds versus 15 minutes, 42 seconds). Initial leak occurred at low pressures on the hand-sewn side (mean pressure 40 mm Hg) compared with the stapled side (mean pressure 70 mm Hg). In 7 of 10 experiments, the leak became too brisk on the hand-sewn side to sustain pressure, compared with 3 of 10 with stapled anastomoses. The stapling device performed well in all cases except when the bovine aorta was too thick for the staples (two cases) or when there was a missed branch at the anastomotic site (one case). These experiments validate the concept and the design of this aortic stapler. There are some limitations in the current design, which will need to be modified before its use in live animals or clinically.

Spinal Cord Ischemia After Thoracic Stent-Grafting: Causes Apart From Intercostal Artery Coverage

Examination of a large collective combined with individual case analyses may give new insights into mechanisms and prevention of spinal cord ischemia (SCI) after thoracic endovascular repair. In an 11-year period, stent-grafts were implanted in 406 patients for various aortic pathologic conditions. The mean age was 63 years (15-91 years) and 300 (74%) patients were men; 58 patients underwent staged thoracic stent-graft procedures. The length of aorta covered was between 75 and 584 mm (mean, 204 mm). Thoracoabdominal branched or fenestrated stent-grafts were implanted in 11 patients. The left subclavian artery was occluded in 161 patients (39%); this occurred in half of them (n = 78) after protective revascularization. Prophylactic cerebrospinal fluid (CSF) drainage was used selectively in 4 cases; no neuromonitoring was used. The incidence of SCI was 2.7% (n = 11); 6 patients (1.5%) had major permanent deficits. Conditions that had a potential influence on SCI were analyzed. Statistical correlation was found for previous conventional or endovascular abdominal aortic aneurysm repair (odds ratio [OR], 4.8), coverage of the entire descending thoracic aorta (OR, 3.6), and implantation of thoracoabdominal branched and fenestrated stent-grafts (OR, 9.5). Individual analyses revealed other conditions that might have played a role, such as embolization into the segmental arteries, severe visceral ischemia, profound hemorrhagic shock, and heparin-induced thrombocytopenia. The incidence of SCI is unexpectedly low despite extensive sacrifice of intercostal arteries. Extended coverage of the thoracic and thoracoabdominal aorta seems to have a higher risk, but other factors may contribute to the individual disaster.

Centerline is Not as Accurate as Outer Curvature Length to Estimate Thoracic Endograft Length

To assess the accuracy of the aortic outer curvature length for thoracic endograft planning. Seventy-four patients (58 men, 66.4 ± 14 years) who underwent thoracic endovascular aortic repair between 2009 and 2011 treated with a Cook Medical endograft were enrolled in this retrospective study. Immediate postoperative CT scans were analysed using EndoSize software. Three vessel lengths were computed between two fixed landmarks placed at each end of the endograft: the straightline (axial) length, the centerline length and the outer curvature length. A tortuosity index was defined as the ratio of the centerline length/straightline length. A Student t test and a Pearson correlation coefficient were used to examine the results. We found a significant difference between the centerline length (135.4 ± 24 mm) and that of the endograft (160 ± 29 mm) (p < .0001). This difference correlates with the tortuosity index (r = .818, p < .0001), the endograft length (r = .587, p < .0001), and the diameter of the endograft (r = .53, p < .0001). However, the outer curvature length (161.3 ± 29 mm) and the endograft length (160 ± 29 mm) were similar (p = .792). The outer curvature length more accurately reflects that of the deployed endograft and may prove more accurate than centerlines in planning thoracic endografts.

Efficacy of thoracic endovascular stent repair for chronic type B aortic dissection with aneurysmal degeneration

The Food and Drug Administration has approved devices for endovascular management of thoracic endovascular aortic aneurysm repair (TEVAR); however, limited data exist describing the outcomes of TEVAR for aneurysms attributable to chronic type B aortic dissection (cTBAD). This study was undertaken to determine the results of endovascular treatment of cTBAD with aneurysmal degeneration. A retrospective analysis of all patients treated for cTBAD with aneurysmal degeneration at the University of Florida from 2004 to 2011 was performed. Computed tomograms with centerline reconstruction were analyzed to determine change in aortic diameter, relative proportions of aortic treatment lengths, and false lumen perfusion status. Reintervention and mortality were estimated using life-tables. Cox regression analysis was completed to predict mortality. Eighty patients underwent TEVAR for aneurysm due to cTBAD (mean age [± standard deviation], 60 ± 13 years [male, 87.5%; n = 70]; median follow-up, 26 [range, 1-74] months). Median time from diagnosis of TBAD to TEVAR was 16 (range, 1-72) months. Prior aortic root/arch replacement had been performed in 29% (n = 23) at a median interval of 28.5 (range, 0.5-312) months. Mean preoperative aneurysm diameter was 62.0 ± 9.9 mm. In 75% (n = 60) of cases, coverage was proximal to zone 3, and 24% (n = 19) underwent carotid-subclavian bypass or other arch debranching procedure. Spinal drains were used in 78% (pre-op 71%, n = 57; post-op 6%, n = 5). Length of stay was 6.5 ± 4.7 days with a composite morbidity of 26% and in-hospital mortality of 2.5% (n = 2). Overall neurologic event rate was 17% (spinal cord ischemia 10% [n = 8], with a permanent deficit observed in 6.2% [n = 5]; stroke 7.5%). Aneurysm diameter reduced or stabilized in 65%. The false lumen thrombosed completely within the thoracic aorta in 52%, and reintervention within the treated aortic segment was required in 16% (n = 13).One- and 3-year freedom from reintervention (with 95% confidence interval [CI]) was 80% (range, 68%-88%) and 70% (range, 57%-80%), respectively. Survival at 1 and 5 years was 89% (range, 80%-94%) and 70% (range, 55%-81%) and was not significantly different among patients requiring reintervention or experiencing favorable aortic remodeling. Multivariable analysis identified coronary artery disease (hazard ratio [HR], 6.4; 95% CI, 2.3-17.7; P < .005), prior infrarenal aortic surgery (HR, 8.6; 95% CI, 2.3-31.7; P = .001), and congestive heart failure (HR, 11.9; 95% CI, 1.9-73.8; P = .008) as independent risk factors for mortality. Hyperlipidemia was found to be protective (HR, 0.2; 95% CI, 0.05-0.6; P = .004). No significant difference in predictors of mortality were found between patients who underwent reintervention vs those who did not (P = .2). TEVAR for cTBAD with aneurysmal degeneration can be performed safely but spinal cord ischemia rates may be higher than previously reported. Liberal use of procedural adjuncts to reduce this complication, such as spinal drainage, is recommended. Reintervention is common, but long-term survival does not appear to be impacted by remediation.

A magnetic resonance perspective of the pulse wave transit time by the Arteriograph device and potential for improving aortic length estimation for central pulse wave velocity

Simple reproducible methods of measuring arterial stiffness, a powerful index of prognosis, are becoming available. To compare the pulse wave transit time (TT) and pulse wave velocity (PWV) between MRI and an arm cuff-based oscillometric method, the Arteriograph. MRI phase-contrast data were acquired at the aortic arch and just above the aortic bifurcation in 49 men (age 53±6 years). Supine left-arm Arteriograph measurements were made after MRI using the surface sternal notch to symphysis pubis pathway length. MRI TT and PWV covered 86% of aortic root-bifurcation length omitting a mean 4.7 cm of proximal ascending aorta. Arteriograph TT (71±9 ms) was 6.6 ms [95% confidence interval (CI) 3.9-9.4] or 10% higher than MRI (64±10 ms). Arteriograph PWV (7.9±1.3 m/s) was 1.33 m/s (95% CI 0.95-1.70) higher than MRI (6.6±1.2 m/s), primarily because the surface aortic length was 70 mm (95% CI 59-81) longer than MRI. Arteriograph-MRI PWV difference decreased to 0.31 m/s (95% CI 0.01-0.61) when Arteriograph PWV was calculated using the MRI aortic path length and to 0.25 m/s (95% CI -0.05 to 0.55) after correcting for the aortic segments omitted in the MRI method. After similar TT corrections for MRI, the Arteriograph-MRI difference in TT reduced to 3.2 ms (95% CI 0.2-6). TT estimations by Arteriograph and MRI are close. More accurate length estimation from MRI-derived models improves Arteriograph PWV measurement.

Aortic Aneurysm Repair Using an Endoprosthesis Designed to Eliminate Endoleaks: Three Year Follow-up

The American Journal of Cardiology APRIL 23e26, 2013 AN aneurysm sac with a quick-setting polymer which is contained in an endobag surrounding the endoprothesis. The filled endobags obliterate the aneurysm sac while providing support and stability to the flow lumens. Methods: All patients enrolled in our center in an IRB-approved prospective clinical trial of the Nellix endograft were reviewed. Pre and post-op CT scan, procedural results, clinical outcome and follow-up CT scans at 1, 6, 12, 24 and 36 months were reviewed. Results: From 2008-2012, 24 patients, aged 69 8 years (5383yrs), with AAA diameter 5.4 0.8 cm (4.2-7.0 cm) were enrolled and treated. Aortic neck length was 25.6 16 mm (8-55mm) with neck length 60 degrees in 6 (25%) and iliac aneurysms >20mm were present in 12 (50%) cases. Complete AAA exclusion was achieved in all by filling endobags with 67 31 ml polymer (24-168 ml). Sac-filling iliac extenders were used to treat 7 common iliac (CI) aneurysms with preservation of hypogastric patency in all. Procedural success was 100%; 30 day mortality and morbidity was 0%. During a mean follow-up of 19 8 months (6-37 mo), there have been no aneurysm related deaths, no device-related adverse events and no secondary procedures. One patient died of CHF at 10 months; one patient had acute MI at 5 months and underwent PTCA. One patient had enlargement of an untreated CI aneurysm and was treated with an iliac extender at 2 years, Follow up CTs demonstrate patent endograft lumens, no device migration, no aneurysm enlargement and no new endoleaks. One patient had a transient, limited-space endoleak at 30 days which was absent at 60 days, 6, 12 and 24 months. There have been no other endoleaks. Conclusion: This novel sac-filling endoprosthesis was successful in eliminating endoleaks following endovascular aneurysm repair. Early results in treating patients with favorable as well as adverse neck and iliac anatomy is promising. This new device appears to eliminate endoleaks and reduce the need for secondary procedures. It may thus improve the long-term durability of endovascular repair. Further studies with a longer follow-up are needed.

Initial experience with the Ventana fenestrated system for endovascular repair of juxtarenal and pararenal aortic aneurysms

Customized fenestrated endovascular stent grafts have been investigated as an alternative to open surgery for repair of more complex juxtarenal aortic aneurysms (JAAs). The substantial time required to design and manufacture these devices has led to the desire for a standardized fenestrated endovascular system. We report the initial pilot study results of a potential "off-the-shelf" fenestrated device system to assess its initial safety and feasibility for endovascular repair of JAAs and pararenal aortic aneurysms (PAAs). Following ethics committee approvals, consenting patients were evaluated for eligibility. Patients with aneurysms abutting or including the renal artery orifices who were not candidates for standard infrarenal endograft placement because of proximal aortic neck morphology were further assessed for anatomic suitability for this "off-the-shelf" device. There were a number of anatomic requirements, the most important being a stable infra-superior mesenteric artery aortic neck length ≥ 15 mm. Patients are assessed in-hospital and in follow-up at 1, 6, and 12 months, and annually thereafter to 5 years for adverse events and using contrast-enhanced computed tomography angiography with Core Laboratory interpretation of renal perfusion, device integrity, migration, endoleak, and aneurysm morphology. Fifteen patients (87% male) with JAAs (93%) or PAAs (6.7%) presented at mean age of 77 years (range, 66-85 years) and with mean sac diameter of 5.9 cm (range, 5.1-7.9 cm). Four Ventana fenestrated stent graft models having aligned fenestrations (three models) or offset fenestrations (one model) and renal stent grafts were successfully implanted among the patients, and all renal and visceral arteries were preserved. Mean endovascular procedure time was 108 minutes (range, 71-212 minutes) with mean contrast usage and fluoroscopy time of 254 mL (range, 67-420 mL) and 55 minutes (range, 27-104 minutes), respectively. Five patients received blood products. Mean time to hospital discharge was 3.3 days (range, 2-9 days). In follow-up to 6 months and 1 year, no rupture, conversion to open repair, migration, type I/III endoleak, or renal loss/infarcts were observed. Two late nonaneurysm-related deaths have occurred. One secondary procedure for iliac limb kinking/occlusion and one secondary procedure for renal artery stenosis have been performed. Early experience supports procedural and initial postprocedural safety and demonstrates proof of concept for the off-the-shelf Ventana fenestrated system for the endovascular repair of JAAs and PAAs in selected patients. Continued follow-up and expanded multicenter clinical experience is warranted.

Preoperative Planning for Endovascular Aortic Repair of Abdominal Aortic Aneurysms: Feasibility of Nonenhanced MR Angiography versus Contrast-enhanced CT Angiography

To compare vascular measurements to determine stent types and configurations for abdominal endovascular aneurysm repair (EVAR) by comparing results of contrast material-enhanced computed tomographic (CT) angiography and nonenhanced magnetic resonance (MR) angiography. This prospective study was institutional review board approved, and all patients provided written informed consent. Fifty patients (45 men and five women; mean age, 76.0 years) admitted for elective abdominal EVAR underwent preoperative abdominal CT angiography (triplanar reformatted images; section thickness of 1-3 mm) and nonenhanced MR angiography (triplanar two-dimensional single-shot turbo field-echo images; section thickness of 6 mm). Two observers independently completed standard measurement and device selection forms for endovascular stent planning for CT and MR angiography. Pearson and intraclass correlation coefficients were calculated to evaluate intermodality and interobserver differences. No significant difference was found in aortic neck diameter (observer 1: CT, 18.5 mm; MR, 19.0 mm; P = .43) (observer 2: CT, 19.6 mm; MR, 19.3 mm; P = .59), aortic neck diameter 15 mm distal to the lowest renal artery (observer 1: CT, 19.2 mm; MR, 19.2 mm; P = .38) (observer 2: CT, 19.6 mm; MR, 19.6 mm; P = .91), aortic neck length (observer 1: CT, 43.6 mm; MR, 43.6 mm; P = .85) (observer 2: CT, 44.4 mm; MR, 44.0 mm; P = .93), or other key vascular measurements (P = .23-.99) for preoperative planning. These included aneurysm diameter, lowest renal artery to aortic bifurcation length, aortic bifurcation diameter, common iliac artery diameters, external iliac artery diameters, length between orifices of lower renal and internal iliac arteries, and iliac artery sealing length. CT and MR angiography measurements showed very strong correlation (r = 0.92-0.99). Intraclass correlation coefficients between observers ranged from 0.90 to 0.98. Stent types and configurations determined with CT measurements remained unaltered when reassessed with MR measurements. Measurements obtained with nonenhanced MR angiography appear equally accurate to those of CT angiography in the preoperative planning of abdominal EVAR.

Quantification of aortic pulse wave velocity in preterm infants using 4D phase contrast MRI

Background 4D phase contrast (PC) MRI sequences providing full coverage of the aortic arch were acquired in neonates. Aortic pulse wave velocity (PWV) was then calculated from flow measurements taken at 5 to 8 locations along the arch and the aortic length between each location. Neonatal PWV values were compared with previously published adult values. Mechanical compliance within the healthy and diseased aorta has been well documented in adults and paediatrics [1,2]. Metafratzi et al [1] reported a PWV range from 4 to 10 ms-1 in the healthy adult aorta, whilst Vulliemoz et al found a mean PWV of 4.4 ms-1 [3]. PWV is an inverse measure of vessel compliance and marker for vessel stiffness. A significant increase in PWV has been found in paediatric subjects born prematurely at low birthweight when studied at ~8yrs and may explain the increase in cardiac disease in this population[2]. However PWV models do not extend back to preterm infants. Recent studies in adults have used PC MRI flow data to determine PWV [4].

Orthotopic Aortic Transplantation in Mice for the Study of Vascular Disease

Vascular procedures involving anastomoses in the mouse are generally thought to be difficult and highly dependent on the skill of the individual surgeon. This is largely true, but there are a number of important principles that can reduce the difficulty of these procedures and enhance reproducibility. Orthotopic aortic transplantation is an excellent procedure in which to learn these principles because it involves only two end-to-end anastomoses, but requires good suturing technique and handling of the vessels for consistent success. This procedure begins with the procurement of a length of abdominal aorta from a donor animal, followed by division of the native aorta in the recipient. The procured aorta is then placed between the divided ends of the recipient aorta and sutured into place using end-to-end anastomoses. To accomplish this objective successfully requires a high degree of concentration, good tools, a steady hand, and an appreciation of how easily the vasculature of a mouse can be damaged, resulting in thrombosis. Learning these important principles is what occupies most of the beginner's time when learning microsurgery in small rodents. Throughout this protocol, we refer to these important points. This model can be used to study vascular disease in a variety of different experimental systems(1-8). In the context shown here, it is most often used for the study of post-transplant vascular disease, a common long-term complication of solid organ transplantation in which intimal hyperplasia occurs within the allograft. The primary advantage of the model is that it facilitates quantitative morphometric analyses and the transplanted vessel lies contiguous to the endogenous vessel, which can serve as an additional control(9). The technique shown here is most often used for mice weighing 18-25 grams. We have accumulated most of our experience using the C57BL/6J, BALB/cJ, and C3H/HeJ strains.

Short-Term Outcomes of the C3 Excluder for Patients With Abdominal Aortic Aneurysms and Unfavorable Proximal Aortic Seal Zones

Endovascular abdominal aortic aneurysm repair (EVAR) in patients with unfavorable proximal seal zones remains challenging. The purpose of this study was to identify the incidence of proximal extension cuff usage for type I endoleaks in patients with abdominal aortic aneurysms and unfavorable necks treated with the C3 Excluder repositionable endoprosthesis compared with the traditional Excluder stent-graft. This is a retrospective review of patients undergoing EVAR with unfavorable neck anatomy from January 2010 to October 2011 using the Excluder endoprosthesis on the traditional deployment system or the C3 repositionable system. Seventy-seven patients were treated with the Excluder device, with 44 (57%) having unfavorable neck anatomy defined as proximal aortic neck length of <15 mm, neck diameter of >28 mm, neck angulation of >60°, circumferential thrombus of >50% or calcification at the proximal seal zone, or a "reverse taper" on computed tomographic angiography. Of the 44 patients with unfavorable neck anatomy, 24patients received the C3 Excluder and 20 received the traditional Excluder. The groups' comorbidities, aneurysm characteristics, and high-risk neck criteria were comparable. Initial success was 100% in both groups. Sixteen of the 44 patients (36%) with high-risk neck criteria required proximal extension cuffs for type I endoleaks, with 3 of the 24patients (13%) in the C3 group compared with 13 of the 20 patients (65%) in the traditional Excluder group requiring proximal extension (P = 0.0005). Operative variables between the two groups were similar. At mean follow-up of 2 months (range: 1-6 months), there were no type I endoleaks or renal artery occlusion, and sac size regression was similar. The C3 Excluder endoprosthesis significantly reduces the need for proximal extension cuffs in patients with unfavorable aortic neck anatomy compared with the traditional Excluder with identical short-term clinical outcomes. Repositionable grafts could increase the number of patients who can effectively be treated with EVAR.

Synergic Effects of Levamlodipine and Bisoprolol on Blood Pressure Reduction and Organ Protection in Spontaneously Hypertensive Rats

Stroke is a major cause of disability and death worldwide. Hypertension is one of the most important risk factors for stroke. The objective of this work was to study the synergic effects of levamlodipine and bisoprolol on blood pressure reduction and organ protection in spontaneously hypertensive rats (SHR). Blood pressure was continuously monitored in conscious SHR. For acute study, a single dose of drugs was administrated via an intragastric catheter. For chronic study (4 months), drugs were delivered via rat chow. A single dose of levamlodipine (from 1 mg/kg), bisoprolol (from 0.125 mg/kg), and their combinations significantly decreased blood pressure. The levamlodipine-induced tachycardia and the bisoprolol-induced bradycardia were temporized by the combination of these two drugs. Upon chronic treatment, this combination also decreased blood pressure variability and reduced organ damage. Levamlodipine and bisoprolol produce synergic effects on blood pressure reduction and organ protection in SHR.

Magnitude and return time of the reflected wave

Increased large artery stiffness is a major determinant of systolic pressure and indicator of cardiovascular events. The reflected wave, its arrival time (return time) and magnitude, contributes to systolic pressure, and is a supposed indicator of aortic stiffness. With aortic stiffening, the return time is assumed to decrease inversely with PWV as 2L/PWV, where L is the aortic length. However, several studies reported that the inflection point of aortic pressure, a surrogate of return time, varies little with aortic stiffness. We studied the effects of aortic stiffness on wave reflection in an anatomically accurate arterial model. Return time is time difference of forward, Pf, and backward, Pb, pressure. Return time, inflection and shoulder points, augmentation index, and reflection magnitude (Pb/Pf) were calculated by standard rules. Peripheral resistance does not affect reflection directly, but only through pressure (stiffness) changes. Magnitude of reflected waves depend about equally on aortic geometry (taper, branches) and distal aortic reflection. Therefore, relations of augmentation index and reflection magnitude with stiffness are nonlinear and complex; augmentation index is most sensitive to stiffness. Between PWV 6 and 12 m/s, representing ages of 20-80 years, return time and inflection and shoulder points change differently with stiffness and PWV cannot be derived from them. Pulse pressure is strongly dependent on aortic stiffness. Taper changes return time by a factor 2, but has little effect on reflection magnitude, augmentation index, and inflection point. Accurate quantitative information on arterial stiffness cannot be obtained from reflection parameters. The augmentation index is most sensitive to stiffness changes.