Iatrogenic Arteriovenous Fistula Formation after Endovenous Laser Treatment Resulting in High-output Cardiac Failure: A Case Report and Review of the Literature.

Formation of a clinically significant iatrogenic arteriovenous fistula after endovenous laser treatment of the great saphenous vein is an extremely rare complication. Because of the infrequency of reported cases, there is no clear consensus on how to best manage this complication. We present a unique case of an iatrogenic high-output superficial femoral artery-common femoral vein fistula resulting in right heart failure and a distal deep vein thrombosis. Deployment of a covered arterial stent graft resulted in resolution of the arteriovenous fistula and high-output cardiac state. Clinically significant arteriovenous fistulas resulting from inadvertent vessel injury during endovenous laser treatment appear to be amenable to percutaneous endovascular interventions. During these challenging endovascular cases, intravascular ultrasonography can be used to help delineate the morphology of the fistula tract and obtain vessel measurements to ensure accurate endoprosthesis sizing and placement.

In Vivo Assessment of Ascending and Arch Aortic Compliance.

BACKGROUND: Dynamic compliance (Cd) of the adult thoracic ascending and arch aorta has had limited in vivo evaluation in patients with aortic disease. This study evaluates aortic compliance using intravascular ultrasound (IVUS) across a range of thoracic aortic diseases. METHODS: Seventy-nine patients undergoing thoracic aortic endovascular procedures had Cd measurements of the ascending aorta proximal to the origin of the brachiocephalic trunk and distal to the origin of the left common carotid artery using IVUS before endograft deployment. Cd was calculated for each segment using the following equation, Cd = ΔD/(D • ΔP) where ΔD = change in aortic diameter, D = diameter in diastole, and ΔP = pulse pressure. RESULTS: Mean Cd of the ascending aorta in all patients (18.4%/mm Hg) and aortic arch (16.5 %/100 mm Hg) did not differ significantly. Compliance was significantly lower in patients being treated for thoracic aortic aneurysm and penetrating ulcer than in patients with traumatic rupture, acute and chronic dissection (P = 0.009). Compliance was significantly higher in patients with aortic transection compared with thoracic aneurysm or penetrating ulcer (P = 0.001). Compliance decreased with age by 0.44 ± 0.06 (P = 0.001) per year in the ascending aorta and 0.41 ± 0.05 (P = 0.001) per year in the aortic arch. Compliance did not increase with diameter when adjusted for age (P = 0.65). Compliance measured in the ascending aorta in 7 patients after descending thoracic aortic endograft repair decreased to 12.6%/100 mm Hg, although not significant (P = 0.18). CONCLUSIONS: Ascending and aortic arch compliance is significantly higher than reported for peripheral vessels. Thoracic aortic compliance decreases with age and is not related to aortic diameter. The results of the present study are important when considering the development of endoprosthesis devices and long-term effects on the thoracic aorta.

Feasibility of endovascular repair of ascending aortic pathologies as part of an FDA-approved physician-sponsored investigational device exemption.

OBJECTIVE: Endovascular treatment of ascending aortic lesions has been reported, but to date, no FDA-approved studies have been conducted to define feasibility and the use of endografts in this particular location or to analyze the critical factors involved. METHODS: Patients were consented for entry into an FDA-approved physician-sponsored investigational device exemption study to investigate the outcome of those with ascending aortic pathologies. These patients were suitable according to the instructions for use for endovascular repair with a Valiant Captivia (Medtronic, Inc, Minneapolis, Minn) thoracic stent graft, a device designed specifically for deployment in the ascending aorta. All patients had sequential gated-cardiac computed tomography scans, with data being entered into the VQI Complex TEVAR software (West Lebanon, NH). All procedures were performed in a hybrid room, with the capability to convert to an open repair to ensure maximal patient protection. The first five patients constituted the feasibility study, with continued enrollment based on initial results and submission of an annual report to the FDA. RESULTS: Thirty-nine patients were screened, and six patients were entered into the physician-sponsored investigational device exemption study. Although there was no early mortality, there was one late death. All patients had sequential computed tomographies and cardiac echocardiograms with no evidence of migration, one type 1a endoleak, one postoperative stroke, and regression of the aortic lesions in the excluded aortic segment. CONCLUSIONS: In this feasibility study, the preliminary evaluation of endovascular treatment for ascending aortic pathologies demonstrates uniform accuracy of deployment and secure fixation up to 17.5 months of follow-up. There is positive remodeling of the excluded aortic segments similar to surveillance studies involving the descending aorta.

Fatigue and in vivo validation of a peritoneum-lined self-expanding nitinol stent-graft.

PURPOSE: To assess the fatigue and in vivo performance of a new stent-graft incorporating bovine peritoneum lining that is designed for application in peripheral vascular occlusive disease. METHODS: Bovine peritoneum-lined stent-grafts were subjected to accelerated in vitro pulsatile fatigue and axial/torsional fatigue testing designed to simulate 10 years of physiological strain on the devices. At specified times the devices were evaluated for stent fracture, suture failure, or tissue tearing. Seven dogs underwent bilateral common iliac artery (CIA) balloon angioplasty injury with unilateral placement of the peritoneum-lined stent-graft. Angiography and intravascular ultrasound were performed prior to treatment, after treatment, and prior to sacrifice at 30 days. Vessels were perfusion fixed and histologically evaluated at 5 regions: above stent, proximal stent, mid stent, distal stent, and below stent. RESULTS: No evidence of stent, suture, or tissue failure was present during or after pulsatile and axial/torsional fatigue testing. At 30±0.3 days after implantation, all vessels were patent. The average lumen area at explantation across stented vessels was 25.45 mm(2). Lumen areas tended to be reduced above (23.57 mm(2)) and below (24.17 mm(2)) the stent. Lumen areas were consistent across stented regions at explantation (proximal stent 27.80 mm(2), mid stent 25.88 mm(2), and distal stent 25.81 mm(2)). The mean neointimal area in peritoneum-lined stents was 2.02±1.52 mm(2), with a neointima:media ratio of 1.03±0.50. These values were significantly lower in the above and below stent areas than in the stented regions, but there was no difference in either measure within the proximal, mid, or distal stent. CONCLUSION: The custom-designed peritoneum-lined stent-graft is promising for clinical peripheral applications due to its ability to resist relevant long-term physiological stresses and outstanding short-term patency rates in canine implantations.

Intravascular ultrasound.

Intravascular ultrasound (IVUS) has an interesting history that parallels that of many of the advancements that have led to the endovascular era. The use of IVUS in conjunction with standard cross-sectional imaging and three-dimensional reconstructions offers a powerful tool in both the diagnosis and treatment of complex vascular pathology. The use of IVUS has increased over the years and is currently in the process of being incorporated into several modalities that will offer more in the way of real-time information in both the aortic arena and the treatment of increasingly complex peripheral vascular disease. Currently, we use IVUS as a powerful adjunct in combination with other modalities to increase our understanding of vessel architecture and assist in the management of complex vascular pathology.

Effects of sildenafil and/or muscle derived stem cells on myocardial infarction.

BACKGROUND: Previous studies have shown that long-term oral daily PDE 5 inhibitors (PDE5i) counteract fibrosis, cell loss, and the resulting dysfunction in tissues of various rat organs and that implantation of skeletal muscle-derived stem cells (MDSC) exerts some of these effects. PDE5i and stem cells in combination were found to be more effective in non-MI cardiac repair than each treatment separately. We have now investigated whether sildenafil at lower doses and MDSC, alone or in combination are effective to attenuate LV remodeling after MI in rats. METHODS: MI was induced in rats by ligature of the left anterior descending coronary artery. Treatment groups were: "Series A": 1) untreated; 2) oral sildenafil 3 mg/kg/day from day 1; and "Series B": intracardiac injection at day 7 of: 3) saline; 4) rat MDSC (106 cells); 5) as #4, with sildenafil as in #2. Before surgery, and at 1 and 4 weeks, the left ventricle ejection fraction (LVEF) was measured. LV sections were stained for collagen, myofibroblasts, apoptosis, cardiomyocytes, and iNOS, followed by quantitative image analysis. Western blots estimated angiogenesis and myofibroblast accumulation, as well as potential sildenafil tachyphylaxis by PDE 5 expression. Zymography estimated MMPs 2 and 9 in serum. RESULTS: As compared to untreated MI rats, sildenafil improved LVEF, reduced collagen, myofibroblasts, and circulating MMPs, and increased cardiac troponin T. MDSC replicated most of these effects and stimulated cardiac angiogenesis. Concurrent MDSC/sildenafil counteracted cardiomyocyte and endothelial cells loss, but did not improve LVEF or angiogenesis, and upregulated PDE 5. CONCLUSIONS: Long-term oral sildenafil, or MDSC given separately, reduce the MI fibrotic scar and improve left ventricular function in this rat model. The failure of the treatment combination may be due to inducing overexpression of PDE5.

Patient outcomes and thoracic aortic volume and morphologic changes following thoracic endovascular aortic repair in patients with complicated chronic type B aortic dissection.

OBJECTIVE: True and false lumen changes and patient outcomes following thoracic endovascular aortic repair (TEVAR) for patients with stable type B dissection have been described by the The Investigation of Stent Grafts in Aortic Dissection (INSTEAD) trial. However, these changes have not been described in TEVAR patients treated for complications of chronic dissection. METHODS: A single-institution study was conducted of 73 prospectively evaluated patients treated for complications of chronic type B dissection from 2002 to 2010. Spiral computed tomography reconstructions using M2S (Medical Media Systems, West Lebanon, NH) were analyzed for sequential changes in aortic volume and diameter during patient follow-up. Changes in aortic volume and diameter were tabulated as a percent change from preoperative values. Patient outcomes were determined by sequential evaluations postprocedure. RESULTS: TEVAR was successfully performed in 72 out of the 73 patients (99%). Indications for intervention were aortic enlargement (n = 62), failure of medical management (n = 7), and perforation (n = 4). The 30-day all-cause mortality rate was 14%; events were due to retrograde dissection (n = 4), cardiac-related (n = 4), and rupture (n = 2). Eleven out of the 72 patients (15%) required a secondary procedure for endoleak (n = 7) and persistent distal perfusion of the false lumen (n = 4). Mean percentage expansion of the thoracic true lumen was noted during the follow-up period: 38%, 46%, 71%, and 114% at 1-, 3-, 6-, and 12-month follow-up, respectively. Concomitant regression of the thoracic false lumen of -65%, -68%, -84%, and -84% was observed at the same intervals, respectively. Patients with an initial extension of the thoracic dissection into the infrarenal aorta (n = 46) had an increase in mean percentage change of aortic diameter and volume to 21% and 17% at 1 year, respectively. By contrast, in the patient group without infrarenal dissection (n = 14), the infrarenal aortic diameter and volume remained relatively unchanged at 3% and -0.9%, respectively, at 1-year postintervention. CONCLUSIONS: TEVAR is a potential treatment option for patients experiencing complications of chronic type B dissection. During follow-up, there is a predictable expansion of the thoracic true lumen and regression of the thoracic false lumen. These findings correlate with those of the INSTEAD trial, which demonstrated false lumen regression and true lumen expansion in a cohort of patients with stable type B dissection. However, many patients with extension of thoracic dissection into the infrarenal aorta demonstrate continued aortic dilation and, on occasion, the need for secondary intervention for persistent distal perfusion. Further analysis is needed in this subgroup of patients so as to better determine potential predictors and the clinical significance of post-TEVAR infrarenal expansion. Moreover, further investigations may support a role for secondary endovascular intervention in remedying persistent infrarenal aortic expansion after TEVAR for chronic dissection.

Predictability of cerebral embolization from aortic arch manipulations during thoracic endovascular repair.

There is no sensitive tool to monitor embolic events and predict patients at a risk for strokes during thoracic endovascular aortic repair. We examined the relationship between the number of high intensity transient signals (HITS) by transcranial doppler ultrasound and the extent of atherosclerotic plaques in aortic arch. Thirteen patients were treated as a part of a single center United States Food and Drug Administration-approved investigational device exemption for various thoracic aortic pathologies. Bilateral transcranial doppler ultrasound transducers recorded the number of HITS. CT angiography and intravascular ultrasound were used to measure the thickness of mural thrombi and determine their arch location. All 13 patients had detectable HITS, and one patient sustained a stroke. Eleven patients had quantifiable mural thrombi. The highest HITS were observed in patients with thrombi in zones 2 to 3. All three patients with bovine arch had more HITS in the right middle cerebral artery whereas the patients with normal arch anatomy had more HITS in the left middle cerebral artery. The presence of mural thrombi in zones 2 and 3, irrespective of their thickness, was associated with increased HITS during thoracic endovascular aortic repair. This is the first study to characterize the significance of mural thrombi in aortic arch and their relationship to embolic events during aortic arch manipulations.

Aortic remodeling, volumetric analysis, and clinical outcomes of endoluminal exclusion of acute complicated type B thoracic aortic dissections.

OBJECTIVE: Structural changes within the aorta after thoracic endovascular aortic repair (TEVAR) for acute complicated type B thoracic aortic dissections (ABAD) remain unknown. This study reviewed and analyzed morphologic changes, volumetric data, and clinical outcomes of patients with ABAD. METHODS: Forty-one consecutive patients with ABAD, all with the volumetric analysis of aortic luminal changes and ≥1 year of follow-up, were treated as a part of a single-center U.S. Food and Drug Administration (FDA)-approved investigational device exemption (IDE) trial from 2002 to 2009. Indications were malperfusion in 17, rupture in 12, chest pain in 6, acute enlargement in 4, and uncontrolled hypertension in 2. Duration of symptoms was ≤14 days. Three-dimensional M2S computed tomography reconstructions (Medical MetRx Solutions, West Lebanon, NH) were analyzed for aortic volume and diameter changes, regression of the false lumen, and expansion of the true lumen. RESULTS: Emergent surgery was required in 17 (42%) patients, excluding one death at induction. Procedural success rate was 92.5%. The 30-day mortality was 4.9% for malperfusion, 4.9% for rupture, and 0% for all others, with late mortality of 0%, 9.8%, and 7.3%, respectively. Mean follow-up was 12.4 months. Permanent stroke and paraplegia rates were 4.9% (n = 2) and 0%. Ten of 12 secondary interventions were performed for 6 proximal endoleaks, 1 distal cuff endoleak, and 3 distal reperfusions. For the 33 patients without endoleaks, the true lumen volume increased by 29% at 1 month, 51% at 1 year, and 80% at 5 years. Volume regression of the false lumen was 69%, 76%, and 86%, respectively. The true lumen volume did not change at 1 month or 1 year in the endoleak group (n = 7) but increased 50% at 2 years after secondary intervention. A 10% reduction of abdominal aortic volume distal to endograft occurred over 5 years in the absence of endoleaks. CONCLUSIONS: TEVAR offers a promising solution to patients with ABAD. Aortic morphologic changes occur shortly after TEVAR and remain predictable up to 5 years with continuous expansion of the true lumen and regression of the false lumen. A lack of increase in the true lumen volume is associated with endoleaks or distal reperfusion.

Crux vena cava filter.

Inferior vena cava filters are widely accepted for pulmonary embolic prophylaxis in high-risk patients with contraindications to anticoagulation. While long-term complications have been associated with permanent filters, retrievable filters are now available and have resulted in the rapid expansion of this technology. Nonetheless, complications are still reported with optional filters. Furthermore, device tilting and thrombus load may prevent retrieval in up to 30% of patients, thereby eliminating the benefits of this technology. The Crux vena cava filter is a novel, self-centering, low-profile filter that is designed for ease of delivery, retrievability and improved efficacy while limiting fatigue-related device complications. This device has been proven safe and user-friendly in an ovine model and has recently been implanted in human subjects.

Midterm results of endovascular treatment of complicated acute type B aortic dissection.

OBJECTIVES: The operative mortality and morbidity of patients with complicated acute type B aortic dissection remain high. The endovascular approach has been proposed as a potential alternative. The purpose of this study is to review the contemporary outcome of patients undergoing endovascular treatment for complicated acute type B aortic dissection. METHODS: A retrospective analysis of 28 patients undergoing endovascular interventions for acute type B aortic dissection was performed. Kaplan-Meier survival analysis was used for statistical computation. RESULTS: Indications for emergency endografting were rupture in 4 (14%) patients, severe lower body malperfusion in 8 (29%) patients, visceral/renal malperfusion in 7 (25%) patients, persistent chest pain despite proper anti-impulsive therapy in 5 (18%) patients, uncontrollable hypertension in 1 (4%) patient, and acute dilatation of false lumen with impending rupture in 3 (11%) patients. Three (11%) patients died early. Three patients died during follow-up of non-aorta-related causes. Overall survival was 82% and 78% at 1 and 5 years' follow-up, respectively. The aorta-related mortality was 10% for the entire follow-up period. Complete thrombosis of the false lumen in the thoracic aorta was achieved in 22 (85%) members of the surviving cohort, and partial thrombosis was achieved in the remainder. The rate of treatment failure according to Stanford criteria was 18% at 5 years. Mean follow-up was 36 months, and follow-up was complete in 28 (100%) patients. CONCLUSIONS: Thoracic aortic endografting for complicated acute type B aortic dissection can be performed with a relatively low postoperative morbidity and mortality in experienced hands. The endovascular approach to life-threatening complications of acute type B aortic dissection appears to have a favorable outcome in midterm follow-up.

High-dose adenosine-induced asystole assisting accurate deployment of thoracic stent grafts in conscious patients.

Adenosine has been used to induce asystole and assist deployment of endoluminal grafts. However, application of high-dose adenosine in conscious patients has not been described. In this prospective study, we administered high-dose adenosine in patients undergoing thoracic stent grafting. Asystole duration in relationship to the dosage of adenosine, safety, and side effect profiles was investigated. All patients who underwent thoracic stent grafting between 1998 and 2006 were the potential study subjects. They received monitored anesthesia care and local anesthesia unless contraindicated. Adenosine was given via rapid intravenous bolus immediately prior to the deployment of the stent graft. Every patient received a dose of 36 mg. If needed, a second dose of 18 mg was given. Duration of asystole was recorded after each administration. Patients' vital signs before and after administration were also documented. Side effect profiles were collected intra- and postoperatively. A total of 46 patients received adenosine (34 men, 12 women). Mean age was 60.4 +/- 17.5 years. American Society of Anesthesiologists scores were II in one patient (2%), III in six patients (13%), and IV in 39 patients (85%). Eighteen patients received a single dose of 36 mg adenosine, 15 were given a second dose of 18 mg, and 13 received nonstandard dosages. Asystole durations were 18.8 +/- 8.8 and 11.6 +/- 5.5 sec for 36 and 18 mg, respectively. Technical success was achieved in all cases. The differences achieved statistical significance (p = 0.0009). There were no severe cardiac or pulmonary complications. High-dose adenosine can be given safely in conscious patients. The dose-response was predictable and reproducible. The dosages used in our study induce sufficient duration of asystole, which ensured accurate deployment of thoracic stent grafts.

Risk factors for early and late mortality after thoracic endovascular aortic repair.

OBJECTIVE: The risk factors associated with death after thoracic endovascular aortic repair are poorly understood. The aim of this study is to analyze the risk factors associated with early and late mortality after thoracic endovascular aortic repair. METHODS: A total of 153 patients underwent 184 thoracic endovascular aortic repairs between 1998 and 2005. Prospectively collected data were entered into statistical software. Univariate and multivariate analyses were performed. RESULTS: The underlying pathologies included descending thoracic aortic aneurysm (n = 91), acute type B aortic dissection (n = 25), chronic type B aortic dissection (n = 42), aortic transection (n = 12), and penetrating aortic ulcer (n = 14). Thoracic endovascular aortic repair was technically successful in all but 3 patients. Another 3 patients required an open repair within the first month. Early and late mortality rates were 9.8% (n = 18) and 19% (n = 35) in a 16-month average period of follow-up, respectively. Type I procedural endoleak was the only significant predictor of early death in the multivariate model (P = .0036; odds ratio: 8.4; 95% confidence interval: 1.6-43.9). Multivariate Cox regression revealed chronic obstructive pulmonary disease (P = .024; odds ratio: 3.8; 95% confidence interval: 1.2-12.1), postoperative myocardial infarction (P = .0053; odds ratio: 9.7; 95% confidence interval: 2.0-48.4), and acute renal failure (P = .0006; odds ratio: 22.8; 95% confidence interval: 3.8-137.6) to be independent risk factors for late mortality. CONCLUSION: Procedural type I endoleak is an independent risk factor of early mortality after thoracic endovascular aortic repair. Chronic obstructive pulmonary disease, postoperative myocardial infarction, and acute renal failure are predictors of late death in the multivariate analysis.

Risk factors of neurologic deficit after thoracic aortic endografting.

BACKGROUND: Stroke and spinal cord injury (SCI) remain the most devastating complications of thoracic endovascular aortic repair (TEVAR). The risk factors associated with these complications are poorly understood. The aim of this study was to analyze the risk factors associated with neurologic deficits after TEVAR. METHODS: From 1998 to 2005, 153 patients underwent 184 TEVARs. Computed tomography scans, angiograms, and medical records were reviewed. TEVAR was completed in all but 3 patients. The underlying pathologies included descending thoracic aortic aneurysm in 91, acute type B aortic dissection in 25, chronic type B aortic dissection in 42, aortic transection in 12, and penetrating aortic ulcer in 14. RESULTS: Stroke developed in 8 patients, and SCI developed in another 8 patients (4 immediate, 4 delayed paraplegia/paraparesis). The procedure-associated stroke and SCI rate was 4.3% (8/184). Univariate statistical analysis revealed increased postoperative stroke with obesity, significant intraoperative blood loss, and evidence of peripheral vascular embolization/thrombosis. Aneurysmal pathology, iliac conduit, and hypogastric artery coverage were highly associated with postoperative SCI after TEVAR. Early and late mortality were 9.8% (n = 18) and 19% (n = 35) in a 16-month average period of follow-up. CONCLUSIONS: The incidence of stroke and SCI after TEVAR was 4.3% (8/184). The risk factors associated with postoperative stroke were obesity, intraoperative blood loss, and vascular embolization. Aneurysm as an underlying pathology, the use of an iliac conduit, and coverage of the hypogastric artery were all associated with SCI. These risk factors for SCI may be markers of tenuous collateral blood supply to the spinal cord.

The role of aortic neck dilation and elongation in the etiology of stent graft migration after endovascular abdominal aortic aneurysm repair with a passive fixation device.

OBJECTIVE: Endovascular repair of abdominal aortic aneurysm (AAA) is complicated by the potential for stent graft migration over time. Factors including the type of fixation, initial proximal fixation length, and dilation and elongation of the infrarenal aortic neck may contribute to device migration. We sought to determine when device migration is a real phenomenon with actual device movement that compromises aneurysm exclusion. METHODS: Computed tomographic (CT) scans and computer reconstructions of all patients undergoing endovascular AAA repair with a passive fixation device at our institution from June 1996 to October 2004 were retrospectively reviewed. The distance from the distal renal artery to the proximal end of the stent graft at the time of initial deployment was determined for each patient. Migration was defined as a distance increase greater than 5 mm in the follow-up period; proximal fixation length, aortic neck enlargement and elongation, and neck angle were then measured. Data were further analyzed with respect to AAA growth, development of endoleak, AAA rupture, and the need for reintervention. RESULTS: A total of 308 patients with endovascular AAA repairs using a passive fixation device had complete postoperative imaging data sets; 48 patients (15.6%) with stent graft migration of 5 mm or more were identified, and 25 (8.1%) of these had a migration of 10 mm or more. Seventeen (35.4%) of 48 migration patients had a total loss of the proximal seal zone (loss patients); their average migration distance was 17.7 +/- 12.0 mm, with a mean neck shortening of 13.6 +/- 14.2 mm, and the average proximal fixation length loss was 14.0 +/- 7.6 mm. Those 31 patients with an intact proximal seal zone (nonloss patients) showed an average migration of 9.4 +/- 3.7 mm, with a mean neck lengthening of 9.6 +/- 8.4 mm and an average proximal fixation length change of 0.7 +/- 8.0 mm. Univariate analysis demonstrated significant differences between the loss and nonloss patients in follow-up duration (65.9 +/- 20.4 months vs 45.9 +/- 26.4 months; P = .01), neck dilatation at the distal renal artery (4.6 +/- 4.5 mm vs 1.8 +/- 1.9 mm; P = .026), stent graft migration distance (17.7 +/- 12.0 mm vs 9.4 +/- 3.7 mm; P = .001), change in aortic neck length (-13.6 +/- 14.2 mm vs 9.6 +/- 8.4 mm; P < .0001), change in proximal fixation length (-14.0 +/- 7.6 mm vs 0.7 +/- 8.0 mm; P < .0001), change in AAA size (1.8 +/- 7.1 mm vs -3.6 +/- 9.7 mm; P = .033), and use of a stiff body stent graft (47.1% vs 19.4%; P = .043). However, only change in aortic neck length was statistically significant on multivariate analysis (odds ratio, 0.75; 95% confidence interval, 0.591-0.961; P = .022). There were no differences between the loss and nonloss patients in time to migration discovery, initial AAA size, initial aortic neck diameter or length, initial device oversizing, initial neck angle, neck angle increase, type II endoleak, or AAA rupture. Eight of the 17 loss patients have been treated with proximal aortic cuffs; the remainder have refused reintervention, died of unrelated causes, or elected to have open repair. CONCLUSIONS: Postoperative elongation of the infrarenal aortic neck may create the radiographic perception of migration without necessarily causing a loss of proximal stent graft fixation. Patients with a total loss of the proximal seal zone actually have infrarenal aortic neck shortening, with a degree of neck dilatation beyond initial device oversizing that may compromise proximal fixation length. Conversely, those with an intact proximal seal zone demonstrate aortic neck elongation equivalent to migration, with no loss of proximal fixation length; these patients have a benign natural history without intervention. Thus, aortic neck dilatation beyond oversizing, aortic neck shortening, and loss of proximal fixation length are more clinically relevant predictors of proximal stent graft failure than simple migration distance.

Principles and devices.

The development of catheter-based ultrasound imaging began in the 1950s using large-diameter catheters and frequencies of between 1 and 10 MHz. In the 1970s, 360 degrees cross-sectional imaging of vessels was reported using multi-element or phase-array transducers. Since then, refinements in imaging frequency, catheter size, image quality, and computer-driven imaging platforms have transformed intravascular ultrasound (IVUS) from predominantly a research tool to an important clinical intervention.

Intravascular ultrasound use in the treatment of thoracoabdominal dissections, aneurysms, and transections.

Intravascular ultrasound (IVUS) has become an important adjunct in the endovascular treatment of thoracoabdominal aortic pathology. In this article, we hope to describe and define the expanding role of IVUS as a tool for the vascular surgeon in the treatment of thoracoabdominal aortic dissections, aneurysms, and transections. IVUS is of particular benefit in the treatment of aortic dissections and aortic transections.

Endograft exclusion of acute and chronic descending thoracic aortic dissections.

OBJECTIVES: To analyze the results of endograft exclusion of acute and chronic descending thoracic aortic dissections (Stanford type B) with the AneuRx (n = 5) and Talent (n = 37) thoracic devices and to compare postoperative outcomes of endograft placement acutely (<2 weeks) and for chronic interventions. METHODS: Patients treated for acute or chronic thoracic aortic dissections (Stanford type B) with endografts were included in this study. All patients (n = 42) were enrolled in investigational device exemption protocols from August 1999 to March 2005. Three-dimensional computed tomography reconstructions were analyzed for quantitative volume regression of the false lumen and changes in the true lumen over time (complete >95%, partial >30%). RESULTS: Forty-two patients, all of whom had American Society of Anesthesiologists (ASA) risk stratification > or =III and 71% with ASA > or = IV, were treated for Stanford type B dissections (acute = 25, chronic = 17), with 42 primary and 18 secondary procedures. All proximal entry sites were identified intraoperatively by intravascular ultrasound (IVUS). The procedural stroke rate was 6.7% (4/60), with three posterior circulation strokes. Procedural mortality was 6.7% (4/60). The left subclavian artery was occluded in 11 patients (26%) with no complaints of arm ischemia, but there was an association with posterior circulation strokes (2/11) (18%). No postoperative paraplegia was observed after primary or secondary intervention. Complete thrombosis of the false lumen at the level of endograft coverage occurred in 25 (61%) of 41 patients < or =1 month and 15 (88%) of 17 patients at 12 months. Volume regression of the false lumen was 66.4% (acute) and 91.9% (chronic) at 6 months. Lack of true lumen volume (contrast) increase and increasing false lumen volume (contrast) suggests continued false lumen pressurization and the need for secondary reintervention. Thirteen patients (31%) required 18 secondary interventions for proximal endoleaks in 6, junctional leaks in 3, continued perfusion of the false lumen from distal re-entry sites in 3, and surgical conversion in 4 for retrograde dissection. CONCLUSIONS: Preliminary experience with endografts to treat acute and chronic dissections is associated with a reduced risk of paraplegia and lower mortality compared with open surgical treatment, the results of medical treatment alone, or a combination.

Impact of an autotransfusion system during endoluminal repair of abdominal aortic aneurysms: does it decrease the use of allogeneic blood?

Endoluminal repair of abdominal aortic aneurysms (AAA) is associated with decreased blood loss and transfusion requirements when compared to open AAA repair. We evaluated the use of an intraoperative autotransfusion system during endoluminal exclusion of AAAs. Fifty endoluminal AAA procedures selected at random were reviewed retrospectively. Patients were divided into 4 groups according to their estimated blood loss: Group I, 20 patients (0-500 cc); Group II, 18 patients (501-1,000 cc); Group III, 7 patients (1,001-1,500 cc); and Group IV, 5 patients (1,501-3,400 cc). The average blood loss was 327 cc for Group I, 728 cc for Group II, 1,217 for Group III, and 2,125, for Group IV. The overall blood loss was 834 cc, but 75 per cent was recovered. Hematuria was always present when greater than 1,000 cc of blood was retransfused, but renal function was not affected even with the concomitant administration of radiographic contrast. Only one patient required an autologous blood transfusion. The use of an autotransfusion device is safe, efficacious, and appears to further limit the need for homologous blood transfusion in patients undergoing endoluminal AAA repair.