W. Anthony Lee

Endovascular repair of traumatic thoracic aortic injury: Clinical practice guidelines of the Society for Vascular Surgery

The Society for Vascular Surgery® pursued development of clinical practice guidelines for the management of traumatic thoracic aortic injuries with thoracic endovascular aortic repair. In formulating clinical practice guidelines, the Society selected a panel of experts and conducted a systematic review and meta-analysis of the literature. They used the Grading of Recommendations Assessment, Development and Evaluation methods (GRADE) to develop and present their recommendations. The systematic review included 7768 patients from 139 studies. The mortality rate was significantly lower in patients who underwent endovascular repair, followed by open repair, and nonoperative management (9%, 19%, and 46%, respectively, P < .01). Based on the overall very low quality of evidence, the committee suggests that endovascular repair of thoracic aortic transection is associated with better survival and decreased risk of spinal cord ischemia, renal injury, graft, and systemic infections compared with open repair or nonoperative management (Grade 2, Level C). The committee was also surveyed on a variety of issues that were not specifically addressed by the meta-analysis. On these select matters, the majority opinions of the committee suggest urgent repair following stabilization of other injuries, observation of minimal aortic defects, selective (vs routine) revascularization in cases of left subclavian artery coverage, and that spinal drainage is not routinely required in these cases.

The Society for Vascular Surgery Practice Guidelines: Management of the left subclavian artery with thoracic endovascular aortic repair

The Society for Vascular Surgery pursued development of clinical practice guidelines for the management of the left subclavian artery with thoracic endovascular aortic repair (TEVAR). In formulating clinical practice guidelines, the society selected a panel of experts and conducted a systematic review and meta-analysis of the literature. They used the grading of recommendations assessment, development, and evaluation (GRADE) method to develop and present their recommendations. The overall quality of evidence was very low. The committee issued three recommendations. Recommendation 1: In patients who need elective TEVAR where achievement of a proximal seal necessitates coverage of the left subclavian artery, we suggest routine preoperative revascularization, despite the very low-quality evidence (GRADE 2, level C). Recommendation 2: In selected patients who have an anatomy that compromises perfusion to critical organs, routine preoperative LSA revascularization is strongly recommended, despite the very low-quality evidence (GRADE 1, level C). Recommendation 3: In patients who need urgent TEVAR for life-threatening acute aortic syndromes where achievement of a proximal seal necessitates coverage of the left subclavian artery, we suggest that revascularization should be individualized and addressed expectantly on the basis of anatomy, urgency, and availability of surgical expertise (GRADE 2, level C).

Collected world and single center experience with endovascular treatment of ruptured abdominal aortic aneurysms

Background:Case and single center reports have documented the feasibility and suggested the effectiveness of endovascular aneurysm repair (EVAR) of ruptured abdominal aortic aneurysms (RAAAs), but the role and value of such treatment remain controversial. Objective:To clarify these we examined a collected experience with use of EVAR for RAAA treatment from 49 centers. Methods:Data were obtained by questionnaires from these centers, updated from 13 centers committed to EVAR treatment whenever possible and included treatment details from a single center and information on 1037 patients treated by EVAR and 763 patients treated by open repair (OR). Results:Overall 30-day mortality after EVAR in 1037 patients was 21.2%. Centers performing EVAR for RAAAs whenever possible did so in 28% to 79% (mean 49.1%) of their patients, had a 30-day mortality of 19.7% (range: 0%–32%) for 680 EVAR patients and 36.3% (range: 8%–53%) for 763 OR patients (P < 0.0001). Supraceliac aortic balloon control was obtained in 19.1% ± 12.0% (±SD) of 680 EVAR patients. Abdominal compartment syndrome was treated by some form of decompression in 12.2% ± 8.3% (±SD) of these EVAR patients. Conclusion:These results indicate that EVAR has a lower procedural mortality at 30 days than OR in at least some patients and that EVAR is better than OR for treating RAAA patients provided they have favorable anatomy; adequate skills, facilities, and protocols are available; and optimal strategies, techniques, and adjuncts are employed.

Endovascular chimney technique versus open repair of juxtarenal and suprarenal aneurysms

OBJECTIVE To compare early outcomes of endovascular repair of juxtarenal and suprarenal aneurysms using the chimney technique with open repair in anatomically-matched patients. METHODS Between January 2008 and December 2009, 21 patients underwent endovascular repair of juxtarenal and suprarenal aortic aneurysms with chimney stenting (Ch-EVAR) of 1 or 2 renal and/or superior mesenteric artery (SMA) vessels. These were compared with 21 anatomically-matched patients that underwent open repair (OR) during the same time period. Primary end points were 30-day mortality, chimney stent patency, and type Ia endoleak. Secondary end points included early complications, renal function, blood loss, and length of stay (LOS). RESULTS Despite a higher proportion of women, oxygen-dependent pulmonary disease and lower baseline renal function, 30-day mortality was identical with one death (4.8%) in each group. Blood loss and total LOS were significantly less for Ch-EVAR. Six patients (29%) in the chimney group had acute kidney injury (AKI) compared with the open group, in which there were one (4.8%) AKI and four (19%) acute renal failures, of which two (9.5%) required chronic hemodialysis. Renal function at 12 months demonstrated similar declines in the overall estimated glomerular filtration rate (eGFR) in the Ch-EVAR and OR groups (11.1 ± 19.6 vs 10.4 ± 25.2, P = NS, respectively). There was one asymptomatic SMA stent occlusion at 6 months and partial compression of a second SMA stent which underwent repeat balloon angioplasty. Primary patency at 6 and 12 months was 94% and 84%, respectively. There was one type Ia endoleak noted at 30 days which resolved by 6 months. CONCLUSIONS Ch-EVAR may extend the anatomical eligibility of endovascular aneurysm repair using conventional devices. It appears to have similar mortality to open repair with less morbidity. Long-term durability and stent patency remain to be determined.

Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR).

PURPOSE To determine the clinical and anatomical risk factors for cerebrovascular accidents (CVA) in patients undergoing thoracic endovascular aortic repair (TEVAR). METHODS Between September 2000 and December 2006, 196 patients (135 men; mean age 68.6+/-13.5 years, range 17-92) underwent TEVAR for a variety of aortic pathologies. The majority (156, 79.6%) were treated with the TAG stent-graft. Demographics, pathologies, intraoperative procedure-related measures, device usage, and postoperative outcomes were assessed. CVA was defined as a new focal or global neurological (motor or sensory) deficit lasting >48 hours associated with acute intracranial abnormalities on computed tomography or magnetic resonance brain imaging. Spinal cord ischemia was excluded. In a subset of patients with planned left subclavian artery (LSA) coverage and an incomplete circle of Willis or a dominant left vertebral artery, prophylactic carotid-subclavian bypasses were performed. RESULTS Nine (4.6%) patients suffered a CVA. Factors not predictive of a CVA on univariate analysis included aortic pathology, urgency of repair, ASA classification, type of anesthesia, blood loss, procedure time, and device used. Proximal extent of repair (with or without extra-anatomical revascularization) was significantly associated with a higher incidence of strokes (zones 0-2 versus 3-4, p=0.025). Five (55.6%) patients with a CVA had documented intraoperative hypotension (systolic blood pressure<80 mmHg). Additionally, while 2 patients had hemispheric infarcts, 5 had acute posterior circulation infarcts involving the cerebellum and brainstem; a single patient had both anterior and posterior circulation infarcts. Seven of the CVA patients had proximal coverage of the thoracic aorta in zones 0-2; of these, 6 had posterior circulation infarcts. Selective LSA revascularization based on preoperative cerebrovascular imaging resulted in lower rates of CVA (6.4% to 2.3%, p=0.30) and posterior circulation infarcts (5.5% to 1.2%, p=0.13). CONCLUSION Proximal extent of repair may serve as a surrogate marker for greater severity of degenerative disease of the aortic arch. Avoidance of intraoperative hypotension and preservation of antegrade vertebral perfusion may be important in prevention of posterior circulation strokes.

A multicenter clinical trial of endovascular stent graft repair of acute catastrophes of the descending thoracic aorta

OBJECTIVE Thoracic endovascular aortic repair (TEVAR) is applicable to a spectrum of thoracic aortic pathology with half of the procedures performed world-wide for indications other than degenerative aneurysm of the descending thoracic aorta (DTA). This multicenter, prospective study queried perioperative and one-year results of TEVAR using the commercially available GORE TAG device, in the treatment of acute complicated Type B dissection (cTBD), traumatic aortic tear (TT), and ruptured degenerative aneurysm (RDA) of the DTA. METHODS This prospective, non-randomized, literature controlled study included 59 patients; cTBD, n = 19; RDA, n = 20; TT, n = 20. The primary end-point was the composite of death and total paraplegia in subjects at <or= 30 days post-treatment compared with a cohort from current literature. Secondary end-points included adverse events related to device, procedural and systemic complications, and one-year survival. RESULTS All 59 patients had successful endoprosthesis deployment. Fifteen of 19 (79%) patients in the cTBD group had either rupture or malperfusion syndromes at presentation. Combined 30-day mortality/paraplegia rate was 13.6% (8/59), with seven (11.9%) deaths (cTBD [3], RDA [3] and TT [1]) and 1 (TT, 1.7%) case of paraplegia. The primary end-point for the TEVAR cohort was significantly lower (P = .008) when compared with a composite literature control of 800 patients (combined 30-day mortality/paraplegia of 29.6%). Thirty-day complications of any nature occurred in 48 (81%) patients; 11 (18.6%) were device related, and 43 (73%) experienced one or more systemic adverse events. Six (10%) patients required additional TEVAR implantations and 3 (5%) patients (one in each pathology group) required conversion to open surgery. Seventeen (29%) patients had endoleaks of any kind or degree through 30 days; cTBD (7), TT (2), RDA (8). Nine patients (15.3%) had perioperative strokes with two resultant deaths. During mean follow-up time of 409 +/- 309 days, an additional 12 patients died, one patient required open conversion (cTBD), and two patients had major device related events. Actuarial survival at one year was 66% (range, 52%-77%) for the entire cohort; (cTBD) 79% (range, 53%-92%), (TT) 79% (range, 53%-92%) and (RDA) 37% (range, 16%-59%). On regression analysis, age at treatment (1.05 [range, 1.01-1.09]; P = .008) and chronic obstructive pulmonary disease (COPD) (4.3 [range, 1.3-14.4]; P = .02) were predictive of death at one year. CONCLUSION This study confirmed treatment advantages for TEVAR for thoracic aortic catastrophes when compared with literature-based results of open repair. One-year treatment results indicate a low incidence of graft-related complications. TEVAR is the preferred initial treatment for the DTA catastrophes studied herein.

Extent of Aortic Coverage and Incidence of Spinal Cord Ischemia After Thoracic Endovascular Aneurysm Repair

BACKGROUND Risk factors for spinal cord ischemia (SCI) after thoracic endovascular aneurysm repair (TEVAR) remain unclear. Aortic coverage was examined as a risk factor for SCI using quantitative three-dimensional computed tomography angiography (CTA) analysis. METHODS The medical records, radiographic imaging studies, and a prospectively maintained database of all TEVAR procedures performed during a 7-year period were retrospectively reviewed. Preoperative anatomic dimensions and postoperative graft path lengths were measured from CTAs using curved planar and orthogonal multiplanar reformations along centerline paths. SCI was defined as transient or permanent lower extremity neurologic deficit without associated intracerebral hemispheric events. RESULTS Of 326 TEVAR cases, 241 patients (74%) had satisfactory imaging. Thirty-three (10%) had SCI. These patients were older (72.7 +/- 10.6 vs 64.7 +/- 15.8 years, p = 0.005) and had longer intraoperative procedure times (137 +/- 65 vs 113 +/- 68 minutes, p = 0.05). Despite similar total lengths of native thoracic aorta (295.0 +/- 36.3 vs 283.1 +/- 39.8 mm, p = 0.17), patients with permanent SCI had a greater absolute (260.5 +/- 40.9 vs 195.8 +/- 81.6 mm, p = 0.002) and proportionate (88.8% +/- 12.1% vs 67.6% +/- 24.0%, p = 0.001) length of aortic coverage. The average length of uncovered aorta proximal to the celiac artery in patients with SCI was 17.3 +/- 21.8 mm vs 63.1 +/- 62.9 mm in patients without SCI (p = 0.0006). Neither the patency of the hypogastric arteries nor left subclavian artery was associated with SCI. CONCLUSIONS The extent and distal location (relative to the celiac artery) of aortic coverage were associated with an increased risk of SCI. Prophylactic measures for spinal cord protection should be considered in patients whose thoracic aortas require extensive coverage.

In Vivo Validation of Numerical Prediction of Blood Flow in Arterial Bypass Grafts

AbstractIn planning operations for patients with cardiovascular disease, vascular surgeons rely on their training, past experiences with patients with similar conditions, and diagnostic imaging data. However, variability in patient anatomy and physiology makes it difficult to quantitatively predict the surgical outcome for a specific patient a priori. We have developed a simulation-based medical planning system that utilizes three-dimensional finite-element analysis methods and patient-specific anatomic and physiologic information to predict changes in blood flow resulting from surgical bypass procedures. In order to apply these computational methods, they must be validated against direct experimental measurements. In this study, we compared in vivo flow measurements obtained using magnetic resonance imaging techniques to calculated flow values predicted using our analysis methods in thoraco–thoraco aortic bypass procedures in eight pigs. Predicted average flow rates and flow rate waveforms were compared for two locations. The predicted and measured waveforms had similar shapes and amplitudes, while flow distribution predictions were within 10.6% of the experimental data. The average absolute difference in the bypass-to-inlet blood flow ratio was 5.4±2.8%. For the aorta-to-inlet blood flow ratio, the average absolute difference was 6.0±3.3%.

Will Endovascular Repair Replace Open Surgery for Abdominal Aortic Aneurysm Repair

ObjectiveTo evaluate of the impact of endovascular aneurysm repair on the rate of open surgical repair and on the overall treatment of abdominal aortic aneurysms (AAAs). MethodsAll patients with AAA who were treated during two consecutive 40-month periods were reviewed. During the first period, only open surgical repair was performed; during the subsequent 40 months, endovascular repair and open surgical repair were treatment options. ResultsA total of 727 patients with AAA were treated during the entire period. During the initial 40 months, 268 patients were treated with open surgical repair, including 216 infrarenal (81%), 43 complex (16%), and 9 ruptured (3%) aortic aneurysms. During the subsequent 40 months, 459 patients with AAA were treated (71% increase). There was no significant change in the number of patients undergoing open surgical repair and no significant difference in the rate of infrarenal (238 [77%]) and complex (51 [16%]) repairs. A total of 353 patients were referred for endovascular repair. Of these, 190 (54%) were considered candidates for endovascular repair based on computed tomography or arteriographic morphologic criteria. Analyzing a subgroup of 123 patients, the most common primary reasons for ineligibility for endovascular repair were related to morphology of the neck in 80 patients (65%) and of the iliac arteries in 35 patients (28%). A total of 149 patients underwent endovascular repair. Of these, the procedure was successful in 147 (99%), and 2 (1%) patients underwent surgical conversion. The hospital death rate was 0%, and the 30-day death rate was 1%. During a follow-up period of 1 to 39 months (mean 12 ± 9), 21 secondary procedures to treat endoleak (20) or to maintain graft limb patency (1) were performed in 17 patients (11%). There were no aneurysm ruptures or aneurysm-related deaths. ConclusionsEndovascular repair appears to have augmented treatment options rather than replaced open surgical repair for patients with AAA. Patients who previously were not candidates for repair because of medical comorbidity may now be safely treated with endovascular repair.

Morbidity with retroperitoneal procedures during endovascular abdominal aortic aneurysm repair

PURPOSE Retroperitoneal iliac procedures can enable successful endovascular repair of abdominal aortic aneurysm (AAA) in patients who otherwise would not be anatomically eligible. The purpose of this study was to determine perioperative outcome with adjunctive retroperitoneal procedures compared with standard bilateral femoral exposure. METHODS Between August 1997 and November 2002, 164 patients underwent elective endovascular AAA repair at a single university medical center. Anatomic, demographic, and early postoperative outcome data gathered prospectively were analyzed. Thirty-two patients (20%) underwent 38 separate adjunctive retroperitoneal procedures. Indications included small external iliac arteries (16 of 32 patients; 50%) and concomitant iliac aneurysm that precluded fixation of the endograft limbs in the common iliac arteries (16 of 32 patients; 50%). The 38 procedures consisted of 8 iliac conduits only, 14 iliac conduits with iliofemoral bypass grafts, and 16 hypogastric revascularization procedures. Data for the study patients were compared with data for 132 patients who underwent endovascular AAA repair through femoral incisions. Primary end points were hospital length of stay, and early morbidity and mortality. RESULTS Retroperitoneal procedures enabled an additional 14% of patients with AAA to undergo endovascular techniques. However, there was a significantly higher proportion of women and patients at high risk for anesthesia (American Society of Anesthesiologists class IV or higher) in the group who underwent retroperitoneal procedures. On average, retroperitoneal procedures were associated with 2.6-fold greater blood loss, 82% longer procedure time, 1.5 days additional hospital stay, and 1.8-fold higher rate of perioperative complications, compared with endovascular AAA repair with femoral exposure alone. In contrast, early mortality was similar in the two groups. CONCLUSION Adjunctive retroperitoneal procedures during endovascular AAA repair are associated with increased risk for complications and longer hospital length of stay, compared with AAA repair with standard femoral exposure only. They do not, however, increase early mortality, even in patients at high risk, and enable a larger subset of patients with AAA to undergo endovascular repair.