Survival and patient-centered outcome in a disease-based observational cohort study of patients with thoracoabdominal aortic aneurysm.

BACKGROUND: Much of the literature describing treatment for thoracoabdominal aortic aneurysm (TAAA) consists of operative series reported by centers of excellence. These studies are limited by referral and selection bias and exclude patients who are not candidates for the reported modality of repair. Little is known about the patients who are not referred or selected for repair. For those undergoing intervention, outcomes such as functional status after surgery are rarely reported. In this study, we address these gaps by reporting two primary end points: 1-year survival and a "good" outcome (defined as successful aneurysm exclusion, freedom from permanent loss of organ system function, and return to preoperative functional status after surgery) in a cohort of TAAA patients, including all nonoperative and operative patients, irrespective of treatment modality. METHODS: A single-institution database was screened by diagnosis codes for TAAA from 2009 to 2017 using the International Classification of Diseases versions 9 and 10. Diagnosis was confirmed by retrospective chart review and computed tomography findings of aneurysmal degeneration ≥3.2 cm of the paravisceral aorta in continuity with aneurysmal aorta meeting standard criteria for repair. Patients <18 years of age and those with mycotic aneurysm were excluded. Patients were either managed nonoperatively or by one of four operative strategies: (i) open; (ii) endovascular with branched endografts; (iii) hybrid, defined as iliovisceral debranching followed by endograft placement; or (iv) partial repair in which the paravisceral segment was intentionally left unaddressed. RESULTS: Among the entire cohort of 432 patients with TAAA, significant comorbidities were seen in 143 (33%). Forty-seven percent of the patients were managed nonoperatively. Of these, 65% survived to 1 year. A survival benefit was seen in the open, endovascular, and partial, but not hybrid, operative groups compared with the nonoperative group during a 3-year period. Overall 1-year survival was 81%, but only 65% had a good outcome (P = .0016). CONCLUSIONS: Nearly half of the patients in this inclusive cohort study did not undergo repair despite access to a variety of operative techniques. Many of these patients die in the short term due to high burden of comorbid disease rather than aneurysm rupture. Among those undergoing operation, a notable difference between survival and good outcome was observed. Operation appears to confer a survival advantage among appropriately selected patients with TAAA, but a large proportion are high risk and may not benefit from operative repair due to limited baseline survival and lower probability of good outcome.

Renal duplex ultrasound findings in fenestrated endovascular aortic repair for juxtarenal aortic aneurysms.

OBJECTIVE: This study characterized duplex ultrasound (DUS) findings and clinical outcomes associated with covered stent placement in renal arteries during fenestrated endovascular aortic repair (FEVAR) to determine if velocity criteria for native renal artery stenosis can be applied. METHODS: Data from a prospectively maintained database of patients who underwent FEVAR between January 2010 and August 2014 were obtained before FEVAR (preoperative or baseline) and at follow-up assessments at 30 days, 6 months, and 1, 2, and 3 years. The established DUS threshold criteria for ≥60% stenosis in native renal arteries were applied at baseline and all follow-up intervals: renal artery peak systolic velocity (PSV) ≥200 cm/s or renal-aortic velocity ratio (RAR) ≥3.5. RESULTS: Forty-nine patients underwent placement of 88 covered renal artery stents during FEVAR. At least 30-day follow-up was available for 43 patients with 80 stents. A ≥60% stenosis was identified in seven renal arteries of six patients on baseline DUS, and these patients were analyzed separately. The remaining 73 renal arteries were classified as normal or <60% stenosis at baseline, with a median PSV of 121 cm/s (interquartile range, 96-143) and median RAR of 1.4 (interquartile range, 1.1-1.7). No significant differences were found between the baseline and follow-up PSV measurements at any time point. The RAR differed significantly at some time points, although median values remained below the ≥60% stenosis threshold. Some increased RAR values were attributed to low aortic velocities after repair. In the 13 patients with 17 covered renal artery stents found to have PSV or RAR exceeding a DUS threshold for ≥60% native renal artery stenosis, there was no evidence of stenosis by computed tomography angiography, of renal dysfunction by estimated glomerular filtration rate, or of renal volume decrease by three-dimensional analysis. None of the seven renal arteries with ≥60% stenosis at baseline showed evidence of restenosis at 1, 2, or 3 years. CONCLUSIONS: Covered stent placement in nonstenotic renal arteries during FEVAR is safe and durable, with PSV and RAR remaining in the normal or <60% stenosis range in most patients. Increases in PSV or RAR that occur are not associated with clinically significant sequelae or in-stent stenosis on computed tomography angiography. DUS velocity criteria for stenosis in native renal arteries appear to overestimate the severity of stenosis in covered stents after FEVAR.

Use of computational fluid dynamics studies in predicting aneurysmal degeneration of acute type B aortic dissections.

OBJECTIVE: Whereas uncomplicated acute type B aortic dissections are often medically managed with good outcomes, a subset develop subacute or chronic aneurysmal dilation. We hypothesized that computational fluid dynamics (CFD) simulations may be useful in identifying patients at risk for this complication. METHODS: Patients with acute type B dissection complicated by rapidly expanding aortic aneurysms (N = 7) were compared with patients with stable aortic diameters (N = 7). Three-dimensional patient-specific dissection geometries were generated from computed tomography angiography and used in CFD simulations of pulsatile blood flow. Hemodynamic parameters including false lumen flow and wall shear stress were compared. RESULTS: Patients with rapid aneurysmal degeneration had a growth rate of 5.3 ± 2.7 mm/mo compared with those with stable aortic diameters, who had rates of 0.2 ± 0.02 mm/mo. Groups did not differ in initial aortic diameter (36.1 ± 2.9 vs 34.4 ± 3.6 mm; P = .122) or false lumen size (22.6 ± 2.9 vs 20.2 ± 4.5 mm; P = .224). In patients with rapidly expanding aneurysms, a greater percentage of total flow passed through the false lumen (78.3% ± 9.3% vs 56.3% ± 11.8%; P = .016). The time-averaged wall shear stress on the aortic wall was also significantly higher (12.6 ± 3.7 vs 7.4 ± 2.8 Pa; P = .028). CONCLUSIONS: Hemodynamic parameters derived from CFD simulations of acute type B aortic dissections were significantly different in dissections complicated by aneurysm formation. Thus, CFD may assist in predicting which patients may benefit from early stent grafting.

Outcomes after stent graft therapy for dissection-related aneurysmal degeneration in the descending thoracic aorta.

OBJECTIVE: Stent graft therapy has emerged as an alternative to open surgery in the management of chronic dissection-related aneurysmal degeneration (DRAD) in the descending thoracic aorta (DTA). The incidence of perioperative complications, need for secondary aortic intervention (SAI), and rate of aneurysmal false-lumen thrombosis have not been thoroughly described. METHODS: Perioperative and midterm outcomes in patients who underwent stent graft therapy for chronic DRAD DTA at a single institution between January 2006 and September 2013 were retrospectively analyzed. Preoperative anatomic factors, including the number of visceral and renal side branches off the false lumen, and false lumen volume, were analyzed for their ability to predict treatment failure. Treatment failure was defined as death, need for a SAI, and failure to achieve thrombosis of the DRAD DTA. Treatment success was defined as thrombosis of the false lumen in the area of the DRAD DTA with stability or a decrease in the maximum diameter of the DRAD DTA. RESULTS: During the study period, 47 patients underwent stent graft therapy for chronic DRAD DTA. Patients were a mean age of 58.3 ± 11.7 years, 74.5% (n = 35) were male, and 14.9% (n = 7) had a history of connective tissue disease. The left subclavian artery was covered in 48.9% (n = 23), and revascularization was performed in 87.0% (n = 20). Spinal drains were used in 74.5% (n = 35). Spinal cord ischemia developed in 6.4% (n = 3), which resolved in two and improved in one. No retrograde aortic dissections occurred. The 30-day mortality was 4.3% (n = 2); one death was in a patient with rupture. Mean clinical follow-up was 35.1 ± 20.9 months. The 5-year Kaplan-Meier survival was 89% ± 5%. Treatment failure occurred in 18 patients (38.3%): 9 required SAIs, 6 did not have thrombosis of the false lumen in the area of the DRAD DTA, and 4 died, with 1 patient dying during a SAI. No preoperative anatomic factor predicted treatment failure. The 5-year freedom from treatment failure was 54% ± 9%. Including the nine patients who underwent SAI, treatment success was achieved in 85.2% of patients. CONCLUSIONS: In this single-center experience of stent graft therapy for chronic DRAD DTA, treatment success was achieved in 85% of patients after a SAI rate of 20%. No preoperative anatomic factor predicted treatment failure, which occurred in almost 40% of the patients. Identifying predictors of treatment failure may improve future outcomes.

Local wall thickness in finite element models improves prediction of abdominal aortic aneurysm growth.

OBJECTIVE: Growing evidence suggests that peak wall stress (PWS) derived from finite element analysis (FEA) of abdominal aortic aneurysms (AAAs) predicts clinical outcomes better than diameter alone. Prior models assume uniform wall thickness (UWT). We hypothesize that the inclusion of locally variable wall thickness (VWT) into FEA of AAAs will improve its ability to predict clinical outcomes. METHODS: Patients with AAAs (n = 26) undergoing radiologic surveillance were identified. Custom MATLAB algorithms generated UWT and VWT aortic geometries from computed tomography angiography images, which were subsequently loaded with systolic blood pressure using FEA. PWS and aneurysm expansion (as a proxy for rupture risk and the need for repair) were examined. RESULTS: The average radiologic follow-up time was 22.0 ± 13.6 months and the average aneurysm expansion rate was 2.8 ± 1.7 mm/y. PWS in VWT models significantly differed from PWS in UWT models (238 ± 68 vs 212 ± 73 kPa; P = .025). In our sample, initial aortic diameter was not found to be correlated with aneurysm expansion (r = 0.26; P = .19). A stronger correlation was found between aneurysm expansion and PWS derived from VWT models compared with PWS from UWT models (r = 0.86 vs r = 0.58; P = .032 by Fisher r to Z transformation). CONCLUSIONS: The inclusion of locally VWT significantly improved the correlation between PWS and aneurysm expansion. Aortic wall thickness should be incorporated into future FEA models to accurately predict clinical outcomes.

The impact of chronic renal insufficiency on vascular surgery patient outcomes.

Renal insufficiency is associated with an increased incidence of poor outcomes, including cardiovascular events and death, in the general population. Renal dysfunction appears to have a particularly negative impact in patients undergoing vascular surgery and endovascular therapy. Although the exact mechanism is unknown, increased levels of inflammatory and biochemical modulators associated with adverse cardiovascular outcomes, as well as endothelial dysfunction, appear to play a role in the association between renal insufficiency and adverse outcomes. Outcomes after the surgical and endovascular treatment of abdominal aortic aneurysms, carotid disease, and peripheral arterial disease are all negatively affected by renal insufficiency. Patients with renal dysfunction may warrant intervention for the treatment of critical limb ischemia and symptomatic carotid stenosis, given the comparatively worse outcomes associated with medical management. Open repair of aortic aneurysms and carotid intervention for asymptomatic disease in patients with severe renal dysfunction should be performed with significant caution, as the risks of repair may outweigh the benefits in this population. Further study is needed to better delineate the risks of medical management for these conditions in patients with coexisting severe renal dysfunction. Lastly, current guidelines for the management of vascular diseases, including objective performance goals for critical limb ischemia, are likely not applicable in patients with severe renal insufficiency.

Incidence, predictors, and outcomes of hemodynamic instability following carotid angioplasty and stenting.

OBJECTIVE: To explore the incidence, predictors, and outcomes of hemodynamic instability (HI) following carotid angioplasty and stenting (CAS). METHODS: We retrospectively evaluated data on 257 CAS procedures performed in 245 patients from 2002 to 2011 at a single institution. The presence of periprocedural HI, as defined by hypertension (systolic blood pressure >160 mm Hg), hypotension (systolic blood pressure <90 mm Hg), and/or bradycardia (heart rate <60 beats per minute), was recorded. Clinically significant HI (CS-HI) was defined as periprocedural HI lasting greater than 1 hour in total duration. Logistic regression was used to analyze the role of multiple demographic, clinical, and procedural variables. RESULTS: Mean age was 70.9 ± 9.9 years (67% male). HI occurred following 84% (n = 216) of procedures. The incidence of hypertension, hypotension, and bradycardia was 54%, 31%, and 60%, respectively. Sixty-three percent of cases involved CS-HI. Recent stroke was an independent risk factor for the development of CS-HI (odds ratio, 5.24; confidence interval, 1.28-21.51; P = .02), whereas baseline chronic obstructive pulmonary disease was protective against CS-HI (odds ratio, 0.34; confidence interval, 0.15-0.80; P = .01). Patients with CS-HI were more likely to experience periprocedural stroke compared to other patients (8% vs 1%; P = .03). There were no significant differences in the incidence of mortality or other major complications between those with and without CS-HI. CONCLUSIONS: HI represents a common occurrence following CAS. While the presence of periprocedural HI alone did not portend a worse clinical outcome, CS-HI was associated with increased risk of stroke. Expeditious intervention to prevent and manage CS-HI is of critical importance in order to minimize adverse clinical events following CAS.

A modern experience with saccular aortic aneurysms.

OBJECTIVE: Repair of saccular aortic aneurysms (SAAs) is frequently recommended based on a perceived predisposition to rupture, despite little evidence that these aneurysms have a more malignant natural history than fusiform aortic aneurysms. METHODS: The radiology database at a single university hospital was searched for the computed tomographic (CT) diagnosis of SAA between 2003 and 2011. Patient characteristics and clinical course, including the need for surgical intervention, were recorded. SAA evolution was assessed by follow-up CT, where available. Multivariate analysis was used to examine potential predictors of aneurysm growth rate. RESULTS: Three hundred twenty-two saccular aortic aneurysms were identified in 284 patients. There were 153 (53.7%) men and 131 women with a mean age of 73.5±10.0 years. SAAs were located in the ascending aorta in two (0.6%) cases, the aortic arch in 23 (7.1%), the descending thoracic aorta in 219 (68.1%), and the abdominal aorta in 78 (24.2%). One hundred thirteen (39.8%) patients underwent surgical repair of SAA. Sixty-two patients (54.9%) underwent thoracic endovascular aortic repair, 22 underwent endovascular aneurysm repair (19.5%), and 29 (25.6%) required open surgery. The average maximum diameter of SAA was 5.0±1.6 cm. In repaired aneurysms, the mean diameter was 5.4±1.4 cm; in unrepaired aneurysms, it was 4.4±1.1 cm (P<.001). Eleven patients (3.9%) had ruptured SAAs on initial scan. Of the initial 284 patients, 50 patients (with 54 SAA) had CT follow-up after at least 3 months (23.2±19.0 months). Fifteen patients (30.0%) ultimately underwent surgical intervention. Aneurysm growth rate was 2.8±2.9 mm/yr, and was only weakly related to initial aortic diameter (R2=.19 by linear regression, P=.09 by multivariate regression). Decreased calcium burden (P=.03) and increased patient age (P=.05) predicted increased aneurysm growth by multivariate analysis. CONCLUSIONS: While SAA were not found to have a higher growth rate than their fusiform counterparts, both clinical and radiologic follow-up is necessary, as a significant number ultimately require surgical intervention. Further clinical research is necessary to determine the optimal management of SAA.

Peak wall stress predicts expansion rate in descending thoracic aortic aneurysms.

BACKGROUND: Aortic diseases, including aortic aneurysms, are the 12th leading cause of death in the United States. The incidence of descending thoracic aortic aneurysms is estimated at 10.4 per 100,000 patient-years. Growing evidence suggests that stress measurements derived from structural analysis of aortic geometries predict clinical outcomes better than diameter alone. METHODS: Twenty-five patients undergoing clinical and radiologic surveillance for thoracic aortic aneurysms were retrospectively identified. Custom MATLAB algorithms were employed to extract aortic wall and intraluminal thrombus geometry from computed tomography angiography scans. The resulting reconstructions were loaded with 120 mm Hg of pressure using finite element analysis. Relationships among peak wall stress, aneurysm growth, and clinical outcome were examined. RESULTS: The average patient age was 71.6 ± 10.0 years, and average follow-up time was 17.5 ± 9 months (range, 6 to 43). The mean initial aneurysm diameter was 47.8 ± 8.0 mm, and the final diameter was 52.1 ± 10.0 mm. Mean aneurysm growth rate was 2.9 ± 2.4 mm per year. A stronger correlation (r = 0.894) was found between peak wall stress and aneurysm growth rate than between maximal aortic diameter and growth rate (r = 0.531). Aneurysms undergoing surgical intervention had higher peak wall stresses than aneurysms undergoing continued surveillance (300 ± 75 kPa versus 229 ± 47 kPa, p = 0.01). CONCLUSIONS: Computational peak wall stress in thoracic aortic aneurysms was found to be strongly correlated with aneurysm expansion rate. Aneurysms requiring surgical intervention had significantly higher peak wall stresses. Peak wall stress may better predict clinical outcome than maximal aneurysmal diameter, and therefore may guide clinical decision-making.

Thoracic endografting reduces morbidity and remodels the thoracic aorta in DeBakey III aneurysms.

BACKGROUND: The efficacy of endovascular treatment of aneurysms secondary to chronic DeBakey type III aortic dissection (CD3) remains controversial. The objective of this study was to compare outcomes from open and endovascular treatment of CD3 aneurysms, and to determine the efficacy of thoracic endovascular aortic repair (TEVAR) in remodeling the chronically dissected thoracoabdominal aorta. METHODS: From 2005 to 2012, 58 patients underwent open aortic replacement (open) and 31 patients underwent endovascular therapy (TEVAR) for the treatment of CD3 aneurysms. The TEVAR patients were divided into CD3a (n = 12) or CD3b (n = 19) subgroups based upon the DeBakey classification of aortic dissection. Total aortic, true and false lumen diameters were measured at different anatomic locations. True lumen and false lumen indices were calculated to evaluate the impact of TEVAR on remodeling. RESULTS: In the open group, operative mortality was 10.3% and the incidence of pulmonary failure, renal failure, and paraplegia was 13.8%, 10.3%, and 12.1%, respectively. There were no operative mortalities in TEVAR patients, and no cases of pulmonary failure, renal failure, or paraplegia. Endovascular therapy stabilized aneurysm size and remodeled the thoracic aorta in 87% of patients. The TEVAR significantly expanded the true lumen and reduced the false lumen within the stent graft in CD3a and CD3b patients (p < 0.001). Thoracic false lumen thrombosis was achieved in 100% of CD3a and in 68% of CD3b patients. CONCLUSIONS: In these early results, TEVAR reduces operative morbidity and mortality compared with open aortic replacement in the treatment of CD3 aneurysms. The TEVAR is effective in remodeling the chronically dissected thoracic aorta. Abdominal false lumen patency is maintained in patients with thoracoabdominal dissection-related aneurysms.

A "fall-back" technique for difficult inferior vena cava filter retrieval.

OBJECTIVE: The purpose of this study was to describe the results of an alternative technique for inferior vena cava filter (IVCF) retrieval that can be used when the retrieval hook cannot be snared. METHODS: Retrospective review of all patients undergoing attempted IVCF retrieval by a single surgeon between March 2009 and March 2011 was undertaken. After December 2009, in cases where the retrieval hook could not be snared, an 18F/85 cm sheath was inserted into the internal jugular vein and a Bentson wire (Cook Medical, Bloomington, Ind) and snare were advanced across separate interstices of the filter. The resulting "lasso" was pulled up below the collar at the top of the filter, and the filter collapsed into the sheath. RESULTS: Over 28 months, 34 patients underwent attempted retrieval of Günther Tulip filters (Cook Medical). Patients were 44±15 years old; 59% were women (n=20). Filters were placed for venous thromboembolism with contraindication to anticoagulation in seven cases and prophylactically in 27 cases. Of the prophylactic cases, 18 (67%) were placed before planned bariatric surgery. Before December 2009, the success rate was 86% (6 of 7): the retrieval hook of one filter could not be snared and seemed to be embedded in the wall of the cava. After adoption of the described technique, the success rate was 96% (26 of 27): one patient refused further attempts at central venous catheterization after multiple unsuccessful attempts. Filters retrieved conventionally by snaring the hook (n=18) were implanted on average for 4.8±3.7 months and 12.1±10.1 months for those retrieved using the new technique (n=14; P=.02). All patients were discharged on the day of the procedure without complication. The one patient in whom the retrieval hook could not be snared before December 2009 has refused another attempt at retrieval. CONCLUSIONS: The method of IVCF retrieval described here was successful in every instance in which it was attempted. It was associated with no morbidity despite the customary use of an 18F sheath in the internal jugular vein. The approach constitutes an appropriate "fall-back" technique when the retrieval hook of a removable IVCF cannot be snared.

Augmented mitral valve leaflet area decreases leaflet stress: a finite element simulation.

BACKGROUND: Using human mitral valve (MV) models derived from three-dimensional echocardiography, finite element analysis was used to predict mechanical leaflet and chordal stress. Subsequently, valve geometries were altered to examine the effects on stresses of the following: (1) varying coaptation area; (2) varying noncoapted leaflet tissue area; and (3) varying interleaflet coefficient of friction (µ). METHODS: Three human MV models were loaded with a transvalvular pressure of 80 mm Hg using finite element analysis. Initially leaflet coaptation was set to 10%, 50%, or 100% of actual coaptation length to test the influence of coaptation length on stress distribution. Next, leaflet surface areas were augmented by 1% overall and by 2% in the noncoapted "belly" region to test the influence of increased leaflet billowing without changing the gross geometry of the MV. Finally, the coefficient of friction between the coapted leaflets was set to µ = 0, 0.05, or 0.3, to assess the influence of friction on MV function. RESULTS: Leaflet coaptation length did not affect stress distribution in either the coapted or noncoapted leaflet regions; peak leaflet stress was 0.36 ± 0.17 MPa at 100%, 0.35 ± 0.14 MPa at 50%, and 0.35 ± 0.15 MPa at 10% coaptation lengths (p = 0.85). Similarly, coaptation length did not affect peak chordal tension (p = 0.74). Increasing the noncoapted leaflet area decreased the peak valvular stresses by 5 ± 2% (p = 0.02). Varying the coefficient of friction between leaflets did not alter leaflet or chordal stress distribution (p = 0.18). CONCLUSIONS: Redundant MV leaflet tissue reduces mechanical stress on the noncoapted leaflets; the extent of coaptation or frictional interleaflet interaction does not independently influence leaflet stresses. Repair techniques that increase or preserve noncoapted leaflet area may decrease mechanical stresses and thereby enhance repair durability.

Qualitative impact of the endovascular era on vascular surgeons' comfort level and enjoyment with open and endovascular AAA repairs.

OBJECTIVE: To evaluate the qualitative impact of training in the endovascular era (post-2000) on vascular surgeons' comfort level and enjoyment with abdominal aortic aneurysm (AAA) repairs. METHODS: A sample of vascular surgeons (n = 1754) were sent a survey pertaining to their fellowship training and practice of AAA repair. The influence of training- and practice-related variables on qualitative outcomes was assessed. RESULTS: A total of 382 (22%) surgeons completed the survey. Surgeons who performed more endovascular aneurysm repairs (EVARs) than open AAA repairs were more likely to enjoy EVAR (P < .001). Those completing fellowship after 2000 reported a higher level of procedure-related comfort with EVAR (P = .001) compared to those completing fellowship before 2000. Conversely, surgeons completing fellowship before 2000 reported a higher level of procedure-related comfort with open AAA repair (P = .001). CONCLUSION: The advent of EVAR has changed fellowship training of AAA repair and has translated into changes in both practice patterns and comfort level.

Stent grafting for aneurysmal degeneration of chronic descending thoracic aortic dissections.

OBJECTIVE: The objective of this study was to examine the results of thoracic endovascular aneurysm repair (TEVAR) for chronic descending thoracic aortic (DTA) dissections with aneurysmal degeneration. METHODS: Over 70 months at a single institution, 27 patients underwent TEVAR for aneurysms related to chronic (>6 weeks) DTA dissections. RESULTS: Mean patient age was 67.5 ± 9.6 years; 18 were men. Primary indications for repair were aneurysm size (n = 20), rapid aneurysmal growth (n = 5), saccular aneurysm (n = 1), and rupture (n = 1). Preoperative false lumen status was patent in 18 patients, partially thrombosed in 8 patients, and unknown in the patient whose aneurysm ruptured. The proximal entry tear was covered in all 27 patients. Fourteen patients required coverage of the left subclavian artery, of which 9 patients underwent prophylactic revascularization. On completion angiogram, no patient had antegrade perfusion of the aneurysmal false lumen. There were three procedural complications: 2 patients sustained paraparesis (one resolved and one improved), and 1 patient had an access injury requiring stent graft placement. Thirty-day mortality was 3.7% (1 of 27); the one death was in the patient whose aneurysm ruptured. Of the 26 surviving patients, 23 (88.5%) had thrombosis of the aneurysmal false lumen. Twenty-two patients (84.6%) had stability or decrease in maximal aneurysm diameter on last radiographic follow-up at 18 ± 20 months. Three-year Kaplan-Meier survival was 90.3% ± 6.5% in the 26 patients who survived to hospital discharge, with a mean follow-up of 27.3 ± 22.1 months. In patients with preoperatively partially thrombosed false lumens (n = 8), 3-year survival was 100%. CONCLUSIONS: TEVAR for aneurysms due to chronic dissections of the DTA can be performed safely and effectively at midterm follow-up according to this single-institution study. Stent graft therapy may be of particular benefit in patients presenting with partially thrombosed false lumens.

Presentation, complications, and natural history of penetrating atherosclerotic ulcer disease.

OBJECTIVES: Increased utilization of computed tomography angiography (CTA) has increased the radiologic diagnosis of penetrating atherosclerotic ulcers (PAUs), which are defined as the ulceration of atherosclerotic plaque through the internal elastic lamina into the aortic media. However, the presentation, treatment indications, and natural history of this disease process remain unclear. METHODS: The radiology database at a single university hospital was searched retrospectively for the CTA diagnosis of PAU from January 2003 to June 2009. All scans were interpreted by a cardiovascular radiologist. Information on PAU characteristics and need for surgical repair due to PAU disease was collected. PAU stability or progression was assessed by follow-up CTA, if available. Only PAUs in the aortic arch, descending thoracic aorta, and abdominal aorta were included. RESULTS: Three hundred eighty-eight PAUs were diagnosed by CTA interpretation. PAU location was in the aortic arch in 27 (6.8%) cases, the descending thoracic aorta in 243 (61.2%) cases, and the abdominal aorta in 118 (29.7%) cases. Two hundred twenty-four (57.7%) PAUs were isolated (without saccular aneurysm or intramural hematoma); 108 (27.8%) PAUs had associated saccular aneurysms; and 56 (14.4%) PAUs had associated intramural hematoma. Rupture was present in 16 (4.1%) cases. Fifty (12.9%) PAUs underwent repair with thoracic endovascular aortic repair (TEVAR) (n = 30), endovascular aneurysm repair (EVAR) (n = 10), or open surgery (n = 10); primary indications for repair were saccular aneurysm (n = 26), rupture (n = 16), and persistent or recurrent symptoms (n = 8). Even if initially treated conservatively with resolution of pain, symptomatic PAU disease was more likely to require repair than asymptomatic PAU disease (36.2% vs 7.8%, P < .001). Follow-up CTA was available for 87 PAUs, 20 (23.0%) of which demonstrated radiographic disease progression at a mean follow-up of 8.4 ± 10.3 months. Symptomatic PAU disease was more likely to progress than asymptomatic disease (42.9% vs 16.7%, P = .029). CONCLUSIONS: For PAUs diagnosed on CTA at a single institution, 4.1% were ruptured and 12.9% underwent repair. Close follow-up imaging appears to be indicated for PAUs, particularly in the case of symptomatic disease, which is more likely to require repair and to undergo radiographic progression.

Increased wall stress of saccular versus fusiform aneurysms of the descending thoracic aorta.

BACKGROUND: Repair of fusiform descending thoracic aortic aneurysms (DTAs) is indicated when aneurysmal diameter exceeds a certain threshold; however, diameter-related indications for repair of saccular DTA are less well established. METHODS: Human subjects with fusiform (n = 17) and saccular (n = 17) DTAs who underwent computed tomographic angiography were identified. Patients with aneurysms related to connective tissue disease were excluded. The thoracic aorta was segmented, reconstructed, and triangulated to create a mesh. Finite element analysis was performed using a pressure load of 120 mm Hg and a uniform aortic wall thickness of 3.2 mm to compare the pressure-induced wall stress of fusiform and saccular DTAs. RESULTS: The mean maximum diameter of the fusiform DTAs (6.0 ± 1.5 cm) was significantly greater (p = 0.006) than that of the saccular DTAs (4.4 ± 1.8 cm). However, mean peak wall stress of the fusiform DTAs (0.33 ± 0.15 MPa) was equivalent to that of the saccular DTAs (0.30 ± 0.14 MPa), as found by using an equivalence threshold of 0.15 MPa. The mean normalized wall stress (peak wall stress divided by maximum aneurysm radius) of the saccular DTAs was greater than that of the fusiform DTAs (0.16 ± 0.09 MPa/cm vs. 0.11 ± 0.03 MPa/cm, p = 0.035). CONCLUSIONS: The normalized wall stress for saccular DTA is greater than that for fusiform DTA, indicating that geometric factors such as aneurysm shape influence wall stress. These results suggest that saccular aneurysms may be more prone to rupture than fusiform aneurysms of similar diameter, provide a theoretical rationale for the repair of saccular DTAs at a smaller diameter, and suggest investigation of the role of biomechanical modeling in surgical decision making is warranted.

Predictors of decreased short- and long-term survival following open abdominal aortic aneurysm repair.

OBJECTIVES: The purpose of this study was to identify predictors of decreased survival after open abdominal aortic aneurysm (AAA) repair at a single university hospital. METHODS: Patients undergoing open AAA repair from June 2003 to June 2009 were identified. Primary outcomes were 30-day and 5-year survival. Preoperative, intraoperative, and postoperative variables were assessed for their influence on outcomes using univariate and multivariate analysis, as appropriate. One- and 5-year survival were determined by Kaplan-Meier analysis. RESULTS: Four hundred eight patients (289 men; 70.8%) with a mean age of 72.4 ± 8.3 years underwent open AAA repair. Sixty-seven patients (16.4%) underwent nonelective repair. The clamp site was infrarenal in 137 patients (33.6%), suprarenal in 97 patients (23.8%), and supraceliac in 174 patients (42.6%). Thirty-day survival was 95.6%. One- and 5-year survival were 90.0% ± 1.5% and 65.1% ± 3.0%, respectively. Seventy-nine patients (19.4%) had decreased renal function postoperatively compared to preoperatively, 71 patients (17.4%) sustained cardiac complications, and 45 patients (11.0%) sustained pulmonary complications. Patients with chronic obstructive pulmonary disease (91.9% vs 97.2%; P = .004) and chronic renal insufficiency (92.0% vs 98.3%; P = .009) had decreased 30-day survival. Patients with chronic obstructive pulmonary disease (55.8% ± 5.8% vs 67.3% ± 3.6%; P = .013), chronic renal insufficiency (51.2% ± 5.2% vs 72.8% ± 3.7%; P = .043), and cerebrovascular disease (46.8% ± 7.4% vs 67.4% ± 3.4%; P = .003) had decreased 5-year survival. Patients who had decreased postoperative renal function (41.0% ± 7.4% vs 72.2% ± 3.4%; P = .004), and patients who sustained pulmonary complications (45.6% ± 8.8% vs 66.3% ± 3.3%; P = .042) had worse 5-year survival. CONCLUSIONS: Open AAA repair can be done with low morbidity and mortality in the era of endovascular aneurysm repair. Careful consideration should be given to preoperative optimization and perioperative care in patients with chronic obstructive pulmonary disease, chronic renal insufficiency, and cerebrovascular disease. Postoperative decrease in renal function and pulmonary complication portend decreased 5-year survival; strategies to ameliorate these factors should be sought.

Increased ascending aortic wall stress in patients with bicuspid aortic valves.

BACKGROUND: Patients with bicuspid aortic valves (BAV) are at increased risk of ascending aortic dilatation, dissection, and rupture. We hypothesized that ascending aortic wall stress may be increased in patients with BAV compared with patients with tricuspid aortic valves (TAV). METHODS: Twenty patients with BAV and 20 patients with TAV underwent electrocardiogram-gated computed tomographic angiography. Patients were matched for diameter. The thoracic aorta was segmented, reconstructed, and triangulated to create a mesh. Utilizing a uniform pressure load of 120 mm Hg, and isotropic, incompressible, and linear elastic shell elements, finite element analysis was performed to predict 99th percentile wall stress. RESULTS: For patients with BAV and TAV, aortic root diameter was 4.0 ± 0.6 cm and 4.0 ± 0.6 cm (p = 0.724), sinotubular junction diameter was 3.6 ± 0.8 cm and 3.6 ± 0.7 cm (p = 0.736), and maximum ascending aortic diameter was 4.0 ± 0.8 cm and 4.1 ± 0.9 cm (p = 0.849), respectively. The mean 99 th percentile wall stress in the BAV group was greater than in the TAV group (0.54 ± 0.06 MPa vs 0.50 ± 0.09 MPa), though this did not reach statistical significance (p = 0.090). When normalized by radius, the 99 th percentile wall stress was greater in the BAV group (0.31 ± 0.06 MPa/cm vs 0.27 ± 0.03 MPa/cm, p = 0.013). CONCLUSIONS: Patients with BAV, regardless of aortic diameter, have increased 99 th percentile wall stress in the ascending aorta. Ascending aortic three-dimensional geometry may account in part for the increased propensity to aortic dilatation, rupture, and dissection in patients with BAV.

Low rehospitalization rate for vascular surgery patients.

OBJECTIVES: Reducing rehospitalization rates has been proposed to improve care, reduce costs, and as a pay-for-performance criterion. Recent review of Medicare claims data indicates that vascular surgery patients have among the highest rates of 30-day rehospitalization at 23.9%. METHODS: We retrospectively examined all live patient discharges (n = 799) from the vascular surgery service at a single university hospital over 12 months. Planned and unplanned 30-day rehospitalizations were distinguished, and predictors of unplanned 30-day rehospitalization were determined. To identify whether patients were readmitted to other hospitals, a prospective study of patient discharges (n = 66) over 1 month was also performed. RESULTS: Ninety-five (11.9%) of the 799 patient discharges from the vascular surgery service were rehospitalized within 30 days. Of these, 71 were unplanned; therefore, the unplanned rehospitalization rate was 8.9%. The most common causes of unplanned 30-day rehospitalization were related to wound complications. Diabetes (P = .039) predicted unplanned 30-day rehospitalization by multivariate analysis. Patients with the diagnosis of critical limb ischemia (14.9%) and patients undergoing open lower extremity revascularization (14.6%) had the highest rates of unplanned 30-day rehospitalization. In the prospective portion of this study, no patient was readmitted to any other hospital. CONCLUSIONS: Relatively low 30-day rehospitalization was accomplished in vascular surgery patients at a single university hospital. Moreover, planned rehospitalizations accounted for approximately 25% of readmissions in vascular surgery patients. Strategies designed to reduce rehospitalization in diabetics may be warranted.

Delayed complications of inferior vena cava filters: case report and literature review.

Inferior vena cava (IVC) filters are frequently placed to prevent pulmonary embolism in patients in whom anticoagulation is contraindicated or ineffective. Delayed erosion of the filter into adjacent vital structures is a rare complication. We report 3 complications of IVC filters managed with both surgical and endovascular therapies. A review of the available literature addresses incidence of delayed IVC filter complications, the approach to these problems, and the role of retrievable IVC filters.