Catherine K. Chang

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

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

Long-term results of open and endovascular revascularization of superficial femoral artery occlusive disease

BACKGROUND First-line treatment for patients with superficial femoral arterial (SFA) occlusive disease has yet to be determined. This study compared long-term outcomes between primary SFA stent placement and primary femoral-popliteal bypass. Periprocedural patient factors were examined to determine their effect on these results. METHODS All femoral-popliteal bypasses and SFA interventions performed in consecutive patients with symptoms Rutherford 3 to 6 between 2001 and 2008 were reviewed. Time-dependent outcomes were analyzed using the Kaplan-Meier method and log-rank test. Cox proportional hazards were performed to determine predictors of graft patency. Multivariate analysis was completed to identify patient covariates most often associated with the primary therapy. RESULTS A total of 152 limbs in 141 patients (66% male; mean age, 66 ± 22 years) underwent femoral-popliteal bypass, and 233 limbs in 204 patients (49% male; mean age, 70 ± 11 years) underwent SFA interventions. Four-year primary, primary-assisted, and secondary patency rates were 69%, 78%, and 83%, respectively, for bypass patients and 66%, 91%, and 95%, respectively, for SFA interventions. Six-year limb salvage was 80% for bypass vs 92% for stenting (P = .04). Critical limb ischemia (CLI) and renal insufficiency were predictors of bypass failure. Claudication was a predictor of success for SFA stenting. Three-year limb salvage rates for CLI patients undergoing surgery and SFA stenting were 83%. Amputation-free survival at 3 years for CLI patients was 55% for bypass and 59% for SFA interventions. Multivariate predictors (odds ratios and 95% confidence intervals) of covariates most frequently associated with first-line SFA stenting were TransAtlantic Inter-Society Consensus II A and B lesions (5.9 [3.4-9.1], P < .001), age >70 years (2.1 [1.4-3.1], P < .001), and claudication (1.7 [1.1-2.7], P = .01). Regarding bypass as first-line therapy, claudicant patients were more likely to have nondiabetic status (5.6 [3.3-9.4], P < .001), creatinine <1.8 mg/dL (4.6 [1.5-14.9], P = .01), age <70 years (2.7 [CI, 1.6-8.3], P < .001), and presence of an above-knee popliteal artery target vessel (1.9 [CI, 1.1-3.4] P = .02). CONCLUSION Indication, patient-specific covariates, and anatomic lesion classification have significant association when determining surgeon selection of SFA stenting or femoral-popliteal bypass as first-line therapy. Patients with SFA disease can have comparable long-term results when treatment options are well matched to patient-specific and anatomic characteristics.

Preoperative prediction of mortality within 1 year after elective thoracic endovascular aortic aneurysm repair

OBJECTIVE Thoracic endovascular aortic repair (TEVAR) is known to have a survival benefit over open repair in patients with descending thoracic aneurysms and has become a mainstay of therapy. Because death before 1 year after TEVAR likely indicates an ineffective therapy, we have created a predictive model for death within 1 year using factors available in the preoperative setting. METHODS A registry of 526 TEVARs performed at the University of Florida between September 2000 and November 2010 was queried for patients with degenerative descending thoracic aneurysm as their primary pathology. Procedures with emergent or urgent indications were excluded. Preoperatively available variables, such as baseline comorbidities, anatomic-, and procedure-specific planning details, were recorded. Univariate predictors of death were analyzed with multivariable Cox proportional hazards to identify independent predictors of 30-day (death within 30 days) and 1-year mortality (death within 1 year) after TEVAR. RESULTS A total of 224 patients were identified and evaluated. The 30-day mortality rate was 3% (n = 7) and the 1-year mortality rate was 15% (n = 33). Multivariable predictors of 1-year mortality (hazard ratios [95% confidence interval]) included: age >70 years (5.8 [2.1-16.0]; P = .001), adjunctive intraoperative procedures (eg, brachiocephalic or visceral stents, or both, concomitant arch debranching procedures; 4.5 [1.9-10.8]; P = .001), peripheral arterial disease (3.0 [1.4-6.7]; P = .006), coronary artery disease (2.4 [1.1-4.9]; P = .02), and chronic obstructive pulmonary disease (1.9 [1.0-3.9]; P = .06). A diagnosis of hyperlipidemia was protective (0.4 [0.2-0.7]; P = .006). When patients were grouped into those with one, two, three, or four or more of these risk factors, the predicted 1-year mortality was 1%, 3%, 10%, 27%, and 54%, respectively. CONCLUSIONS Factors are available in the preoperative setting that are predictive of death within 1 year after TEVAR and can guide clinical decision making regarding the timing of repair. Patients with multiple risk factors, such as age ≥ 70 years, coronary artery disease, chronic obstructive pulmonary disease, and a need for an extensive procedure involving adjunctive therapies, have a high predicted mortality within 1 year and may be best served by waiting for a larger aneurysm size to justify the risk of intervention.

Transcaval embolization as an alternative technique for the treatment of type II endoleak after endovascular aortic aneurysm repair

The purpose of this report is to highlight our experience with transcaval embolization (TCE) for the management of type II endoleaks (T2Es) as well as to provide a technical description of how to improve procedural safety and success. All patients underwent transfemoral venous access with transcaval puncture into the excluded aneurysm sac with coil placement and selective thrombin injection. Six patients (100% male; mean age [standard deviation] 72.7 [10.8] years) underwent TCE. Technical success was 100% with no postoperative complications. At median follow-up of 8.1 months (range, 2-22 months), two patients had persistent T2Es, with one requiring repeat TCE and the other having cessation of aneurysm growth. The TCE provides a practical alternative to transarterial or translumbar access for the management of T2E, with high degrees of technical and clinical success in this small case series. Larger patient numbers and longer-term follow-up are needed to define procedural efficacy and durability.

Pathology-specific secondary aortic interventions after thoracic endovascular aortic repair

OBJECTIVE Despite improved short-term outcomes, concerns remain regarding durability of thoracic endovascular aortic repair (TEVAR). The purpose of this analysis was to evaluate the pathology-specific incidence of secondary aortic interventions (SAI) after TEVAR and their impact on survival. METHODS Retrospective review was performed of all TEVAR procedures and SAI at one institution from 2004-2011. Kaplan-Meier analysis was used to estimate survival. RESULTS Of 585 patients, 72 (12%) required SAI at a median of 5.6 months (interquartile range, 1.4-14.2) with 22 (3.7%) requiring multiple SAI. SAI incidence differed significantly by pathology (P = .002) [acute dissection (21.3%), postsurgical (20.0%), chronic dissection (16.7%), degenerative aneurysm (10.8%), traumatic transection (8.1%), penetrating ulcer (1.5%), and other etiologies (14.8%)]. Most common indications after dissection were persistent false lumen flow and proximal/distal extension of disease. For degenerative aneurysms, SAI was performed primarily to treat type I/III endoleaks. SAI patients had a greater mean number of comorbidities (P < .0005), stents placed (P = .0002), and postoperative complications after the index TEVAR (P < .0005) compared with those without SAI. Freedom from SAI at 1 and 5 years (95% confidence interval) was estimated to be 86% (82%-90%) and 68% (57%-76%), respectively. There were no differences in survival (95% confidence interval) between patients requiring SAI and those who did not [SAI 1-year, 88% (77%-93%); 5-year, 51% (37%-63%); and no SAI 1-year, 82% (79%-85%); 5-year, 67% (62%-71%) (log-rank, P = .2)]. CONCLUSIONS SAI after TEVAR is not uncommon, particularly in patients with dissection, but does not affect long-term survival. Aortic pathology is the most important variable impacting survival and dictated need, timing, and mode of SAI. The varying incidence of SAI by indication underscores the need for diligent surveillance protocols that should be pathology-specific.

Subclavian Revascularization in the Age of Thoracic Endovascular Aortic Repair and Comparison of Outcomes in Patients with Occlusive Disease

OBJECTIVE Open surgical revascularization for subclavian artery occlusive disease (OD) has largely been supplanted by endovascular treatment despite the excellent long-term patency of bypass. The indications for carotid-subclavian bypass (C-SBP) and subclavian transposition (ST) have been recently expanded with the widespread application of thoracic endovascular aortic repair (TEVAR), primarily to augment proximal landing zones or treat endovascular failures. This study was performed to determine the outcomes of patients undergoing C-SBP/ST in the context of contemporary endovascular therapies and evolving indications. METHODS A prospective database including all procedures performed at a single institution from 2002 to 2012 was retrospectively queried for patients who underwent subclavian revascularization for TEVAR or OD indications. Patient demographics and perioperative outcomes were recorded. Patency was determined by computed tomography angiography in the TEVAR group. Noninvasive studies were used for the OD patients. Life-table methods were used to estimate patency, reintervention, and survival. RESULTS Of 139 procedures identified, 101 were performed for TEVAR and 38 for OD. All TEVAR patients underwent C-SBP/ST to augment landing zones (49% preoperative; 41% intraoperative), treat arm ischemia (8% postoperative), or for internal mammary artery salvage (2%). OD patients had a variety of indications, including failed stent/arm fatigue, 49%; asymptomatic >80% internal carotid stenosis with concurrent subclavian occlusion, 18%; symptomatic cerebrovascular OD, 13%; redo bypass, 8%; and coronary-subclavian steal, 5%. Differences in postoperative stroke and death, primary patency, or freedom from reintervention were not significant. The 30-day postoperative stroke, death, and combined stroke/death rates were, respectively, 10.8%, 5.8%, and 13.7% for the entire cohort; 8.9%, 7.1%, and 12.9% in TEVAR patients; and 15.8%, 2.6%, and 15.8% in OD patients. The 1- and 3-year primary patencies were, respectively, 94% and 94% for TEVAR and 93% and 73% for OD patients. Survival was similar between the groups, with an estimated survival rate of 88% at 1 year and 76% at 5 years. CONCLUSIONS Stroke risk in this contemporary series of C-SBP/ST performed for TEVAR and OD indications may be higher than previously reported in historical series. In TEVAR patients, this may be attributed to procedural complexity of the TEVAR in patients requiring subclavian revascularization. In OD patients, this is likely due to the changing patient population that requires more frequent concomitant carotid interventions. Despite the short-term morbidity, excellent bypass durability and equivalent long-term patient survival can be anticipated.

Safety of elective management of synchronous aortic disease with simultaneous thoracic and aortic stent graft placement

BACKGROUND Simultaneous treatment of multilevel aortic disease is controversial due to the theoretic increase in morbidity. This study was conducted to define the outcomes in patients treated electively with simultaneous thoracic endovascular aortic aneurysm repair (TEVAR) and abdominal aortic endovascular endografting for synchronous aortic pathology. METHODS Patients treated with simultaneous TEVAR and endovascular aneurysm repair (T&E) at the University of Florida were identified from a prospectively maintained endovascular aortic registry and compared with those treated with TEVAR alone (TA). The study excluded patients with urgent or emergency indications, thoracoabdominal or mycotic aneurysm, and those requiring chimney stents, fenestrations, or visceral debranching procedures. Demographics, anatomic characteristics, operative details, and periprocedural morbidity were recorded. Mortality and reintervention were estimated using life-table analysis. RESULTS From 2001 to 2011, 595 patients underwent TEVAR, of whom 457 had elective repair. Twenty-two (18 men, 82%) were identified who were treated electively with simultaneous T&E. Mean ± standard deviation age was 66 ± 9 years, and median follow-up was 8.8 months (range, 1-34 months). Operative indications for the procedure included dissection-related pathology in 10 (45%) and various combinations of degenerative etiologies in 12 (55%). Compared with TA, T&E patients had significantly higher blood loss (P < .0001), contrast exposure (P < .0001), fluoroscopy time (P < .0001), and operative time (P < .0001). The temporary spinal cord ischemia rate was 13.6% (n = 3) for the T&E group and 6.0% for TA (P = .15); however, the permanent spinal cord ischemia rate was 4% for both groups (P = .96). The 30-day mortality for T&E was 4.5% (n = 1) compared with 2.1% (n = 10) for TA. Temporary renal injury (defined by a 25% increase over baseline creatinine) occurred in two T&E patients (9.1%), with none requiring permanent hemodialysis; no significant difference was noted between the two groups (P = .14). One-year mortality and freedom from reintervention in the T&E patients were 81% and 91%, respectively. CONCLUSIONS Acceptable short-term morbidity and mortality can be achieved with T&E compared with TA, despite longer operative times, greater blood loss, and higher contrast exposure. There was a trend toward higher rates of renal and spinal cord injury, so implementation of strategies to reduce the potential of these complications or consideration of staged repair is recommended. Short-term reintervention rates are low, but longer follow-up and greater patient numbers are needed to determine procedural durability and applicability.

Elective endovascular aortic repair conversion for type Ia endoleak is not associated with increased morbidity or mortality compared with primary juxtarenal aneurysm repair

OBJECTIVE Type Ia endoleak after endovascular aortic repair (EVAR) can be a challenging complication to manage, and due to concerns regarding morbidity and mortality of open surgical conversion (OSC), reports of complex endoluminal salvage techniques are increasing. Despite development of these endovascular remedial strategies, many patients ultimately require OSC. The purpose of this analysis was to outcomes of elective OSC for type Ia endoleak and compare them with elective primary open juxtarenal aneurysm repair (OJAR) to determine if these concerns are warranted. METHODS From 2000 to 2012, 54 patients underwent EVAR OSC at median time of 27 months (interquartile range, 9-55 months). Indications included endograft thrombosis in 2 (4%), intraoperative EVAR failure in 3 (6%), rupture in 5 (9%), graft infection in 6 (11%), and type Ia endoleak in 25 (all: 38 [70%]). Because many OSCs are performed for emergency indications without endovascular options, we chose elective type Ia endoleak patients as our study group. These 25 patients were compared with an elective OJAR cohort matched by anatomy and comorbidities. Primary end points were 30-day and 1-year mortality. Secondary end points included early complications, cross-clamp time, procedure time, blood loss, and length of stay. RESULTS Demographic and comorbidity data in the OSC and OJAR groups did not differ, with the exception that OJAR patients presented with smaller aneurysm diameter and a higher rate of chronic obstructive pulmonary disease (P = .03). OSC patients more frequently underwent a nontube graft repair (OSC, n = 20 [80%] vs OJAR, n = 6 [24%]; P = .0002), required longer procedure times (P = .03), and received more plasma transfusions (P = .03). The 30-day mortality was 4% in both groups (observed difference in rates, 0%; 95% confidence interval for difference in mortality rates, -14.0% to 14.0%; P = 1). A similar rate of major complications occurred (OSC, n = 9 [36%] vs OJAR, n = 8 [32%]; P = 1). One-year survival was 83% in OSC and 91% in OJAR (observed difference, 7%; 95% confidence interval, -15% to 29%; P = .65). CONCLUSIONS Despite many advances in EVAR technology, the need for OSC persists and will likely become more common as older-generation devices fail or providers attempt EVAR in more anatomically complex patients. Elective OSC for type Ia endoleak can be technically challenging but is not associated with increased morbidity or mortality compared with OJAR in appropriately selected patients. These results should be considered before pursuing complex endovascular remediation of EVAR failures.

Fate of Aneurysmal Common Iliac Artery Landing Zones Used for Endovascular Aneurysm Repair

Purpose: To determine outcomes of aneurysmal common iliac arteries (aCIA) used for landing zones (LZs) during endovascular aneurysm repair (EVAR). Methods: This single-center study retrospectively compared 57 EVAR patients (mean age 72±8 years; 56 men) with 70 aCIAs (diameter ≥20 mm) to 25 control EVAR subjects (mean age 73±7 years; 20 men) with 50 normal (≤15-mm) CIA LZs treated consecutively during the same time interval. The CIA LZ measurements were analyzed using random effects linear mixed models to determine diameter change over time. Life tables were used to estimate freedom from endoleak, reintervention, and all-cause mortality. Results: The mean maximum preoperative CIA diameter in the aCIA LZ group was 24.8±4.5 mm (range 20.0–47.3, median 23.9) vs 13.6±1.5 mm (range 9.2–15.0, median 13.9; p<0.001) in the controls. Nineteen aCIA LZs were treated outside the instructions for use of the device. Median follow-up in the aCIAs LZ cohort was 39.2 months [interquartile range (IQR) 15, 61] vs 49.3 months (IQR 36, 61) in the controls (p=0.06). The rate of aCIA LZ change (0.09 mm/mo, 95% CI 0.07 to 0.1) was significantly greater than controls (0.03 mm/mo, 95% CI −0.009 to 0.07; p<0.0001). No type Ib endoleaks developed in either group; however, aCIA LZ patients had 6 (11%) iliac limb–related reinterventions. There were significantly more endograft-related reinterventions in the aCIA LZ patients (n=10, 14%) compared with controls (n=2, 4%; p=0.06). There was no difference in mortality or freedom from any post–hospital discharge endoleak. Conclusion: Aneurysmal CIA LZs used during EVAR experience greater dilatation compared with normal LZs, but no significant difference in outcome was noted in midterm follow-up. However, an increased incidence of graft limb complications or endograft-related reintervention may be encountered. Use of aCIA LZs appears to be safe; however, greater patient numbers and longer follow-up are needed to understand the clinical implications of morphologic changes in these vessels when used during EVAR.

Defining utility and predicting outcome of cadaveric lower extremity bypass grafts in patients with critical limb ischemia

OBJECTIVE Despite poor long-term patency, acceptable limb salvage has been reported with cryopreserved saphenous vein bypass (CVB) for various indications. However, utility of CVB in patients with critical limb ischemia (CLI) remains undefined. The purpose of this analysis was to determine the role of CVB in CLI patients and to identify predictors of successful outcomes. METHODS A retrospective review of all lower extremity bypass (LEB) procedures at a single institution was completed, and CVB in CLI patients were further analyzed. The primary end point was amputation-free survival. Secondary end points included primary patency and limb salvage. Life tables were used to estimate occurrence of end points. Cox regression analysis was used to determine predictors of limb salvage. RESULTS From 2000 to 2012, 1059 patients underwent LEB for various indications, of whom 81 received CVB for either ischemic rest pain or tissue loss. Mean age (± standard deviation) was 66 ± 10 years (male, 51%; diabetes, 51%; hemodialysis dependence, 12%), and 73% (n = 59) had history of failed ipsilateral LEB or endovascular intervention. None had sufficient autogenous conduit for even composite vein bypass. Infrainguinal CVB (infrapopliteal target, 96%; n = 78) was completed for multiple indications including Rutherford class 4 (42%; n = 34), class 5 (40%; n = 32), and class 6 (18%; n = 15). Eleven (14%) had CLI and concomitant graft infection (n = 8) or acute on chronic ischemia (n = 3). Intraoperative adjuncts (eg, profundaplasty, suprainguinal stent or bypass) were completed in 49% (n = 40) of cases. Complications occurred in 36% (n = 29), with 30-day mortality of 4% (n = 3). Median follow-up for CLI patients was 11.8 (interquartile range, 0.4-28.4) months with corresponding 1- and 3-year actuarial estimated survival (± standard error mean) of 84% ± 4% and 62% ± 6%. Primary patency of CVB for CLI was 27% ± 6% and 17% ± 6% at 1 and 3 years, respectively. Amputation-free survival was 43% ± 6% and 23% ± 6% at 1 and 3 years, respectively, and significantly higher for rest pain (59% ± 9%, 36% ± 10%) compared with tissue loss (31% ± 7%, 14% ± 7%; log-rank, P = .04). Freedom from major amputation after CVB for CLI was 57% ± 6% and 43% ± 7% at 1 and 3 years. Multivariable predictors of limb salvage for the CVB CLI cohort included postoperative warfarin (hazard ratio [HR], 0.4; 95% confidence interval [CI], 0.2-0.8), dyslipidemia (HR, 0.4; 95% CI, 0.2-0.9), and rest pain (HR, 0.4; 95% CI, 0.2-0.9). Predictors of major amputation included graft infection (HR, 3.1; 95% CI, 1.1-9.0). CONCLUSIONS In CLI patients with no autologous conduit and prior failed infrainguinal bypass, CVB outcomes are disappointing. CVB performs best in patients with rest pain, particularly those who can be anticoagulated with warfarin. However, it may be an acceptable option in patients with minor tissue loss or concurrent graft infection, but consideration should be weighed against the known natural history of nonrevascularized CLI and nonbiologic conduit alternatives, given potential cost implications.