Tara M. Mastracci

Branched endografts for thoracoabdominal aneurysms.

PURPOSE Endovascular management of thoracoabdominal aneurysms has been studied since 2001, with marked advances allowing for the treatment of complex anatomic situations including chronic aortic dissections, tortuous anatomy, and extensive aneurysms that involve the visceral segment, aortic arch, and iliacs as well. However, the technology is not widely disseminated, and a thorough understanding of the engineering principles, imaging techniques, and devices available is required. METHODS Reinforced fenestrated branches coupled with balloon expandable stent grafts, and side-arm branch designs mated with self-expanding stent grafts have been used. Pure fenestrated designs were used for juxtarenal aneurysms, whereas thoracoabdominal aneurysms were treated with reinforced fenestrated branches or hybrid devices including side-arm branches and reinforced fenestrated branches. Intraoperative fusion techniques have been used since 2009, whereby preoperative computed tomographic data are fused with intraoperative fluoroscopy. Long-term survival in accordance with extent of disease was assessed with life table analysis techniques, and differences were analyzed using the log rank test. Intermediate-term data pertaining to patency related to both types of branches and paraplegia have been evaluated and previously published. RESULTS A total of 406 patients with thoracoabdominal aneurysms and 227 patients with juxtarenal aneurysms have been enrolled in a prospective study. Perioperative and 2-year survival were most closely related to extent of initial disease and were estimated to be 1.8% and 82% for juxtarenal aneurysms, 2.3% and 82% for type IV, and 5.2% and 74% for type II and III thoracoabdominal aneurysms at 24 months, respectively. When patients undergoing endovascular repair (ER group) were matched with those having contemporary surgical repair (SR group) for anatomic disease extent, mortality was similar at 30 days (5.7% ER vs 8.3% SR; P = .2) and at 12 months (15.6% ER vs 15.9% SR; P = .9). Paraplegia risk was also similar between the 2 groups (4.3% ER vs 7.5% SR, respectively; P = .08). Among the 633 patients, there were 5 (0.8%) late ruptures at a mean of 18 months after treatment, of which 4 were fatal. They were attributed to component separation (n = 3), a remote aneurysm rupture proximal to the endovascular repair, and a failed surgical polyester graft distal to the repair. Reinforced fenestrated branch patency, when coupled with balloon-expandable stent grafts, was 97.8% at a mean follow-up of 15 months. Side-arm branch occlusion occurred in only 1 case, within 24 hours of the procedure. New imaging tools resulted in a marked reduction in the average contrast dose (>50%). CONCLUSIONS Intermediate-term results with multiple methods of endovascular repair of thoracoabdominal aneurysm indicate the technical feasibility of the procedure and show great promise in patients considered at high risk for open surgery. The intermediate-term patency and survival are excellent, and ruptures are exceedingly uncommon. However, mortality and spinal cord ischemia risks are still considerable with this technique.

Endovascular repair of ruptured abdominal aortic aneurysms: A systematic review and meta-analysis

OBJECTIVES The perioperative mortality for people with ruptured abdominal aortic aneurysms (RAAA) has not changed for two decades. Of patients who survive long enough to undergo open repair for ruptured aneurysms, half die (48%; 95% confidence interval [CI] 46 to 50). Randomized trials have shown that endovascular aneurysm repair (EVAR) for nonruptured abdominal aortic aneurysms decreases perioperative mortality compared with open repair. EVAR may similarly benefit patients with RAAA. We aimed to summarize studies of patients undergoing EVAR for ruptured aneurysms. METHODS Two reviewers searched Medline and EMBASE databases from 1994 to July 2006, Cochrane Database of Systematic Reviews, the Database of Abstracts of Reviews of Effectiveness, the Cochrane Central Register of Controlled Trials, Best Evidence 1994 to 2006, reference lists, clinical trial registries, and conference proceedings; we also contacted authors. All published and unpublished studies in which a group of people with ruptured aneurysms, assessed objectively by imaging, was treated with EVAR (REVAR) were eligible. We used the generic inverse variance function of the REVMAN software to pool results for death in hospital. Sensitivity analyses, using prespecified subgroups, explored heterogeneity between studies. RESULTS Pooled mortality in 18 observational studies describing 436 people who underwent REVAR was 21% (95% CI 13 to 29); however, 90% of the heterogeneity between studies was not explained by chance alone. Surgical volume explained substantial heterogeneity. According to study-specific criteria, 47% (95% CI 39 to 55) of people with ruptured aneurysms were potentially eligible for REVAR. CONCLUSIONS Mortality in people who underwent REVAR is lower than that in historical reports of unselected people undergoing open repair. Further investigation is needed to determine whether the difference in mortality is attributable to patient selection alone or to this new approach to treatment.

Durability of branches in branched and fenestrated endografts

OBJECTIVE Branched and fenestrated repair has been shown to be effective for treatment of complex aortic aneurysms. However, the long-term durability of branches is not well reported. METHODS Prospective data collected for all patients enrolled in a physician-sponsored investigational device exemption trial for branched and fenestrated endografts were analyzed. Retrospective review of imaging studies and electronic records was used to supplement the dataset. Incidences of branch stent secondary intervention, stent fracture, migration, branch-related rupture, and death were calculated. A time-to-event analysis was performed for secondary intervention for any branch. Univariable and multivariable analyses were performed to identify related variables. Branch instability, a composite outcome of any branch event, was reported as a function of exponential decay to capture the loss of freedom from complications over time. RESULTS Between the years 2001 and 2010, 650 patients underwent endovascular aortic repair with branched or fenestrated devices. Over 9 years of follow-up (mean [standard deviation], 3 [2.3] years), secondary procedures were performed for 0.6% of celiac, 4% of superior mesenteric artery (SMA), 6% of right renal artery, and 5% of left renal artery stents. Mean time to reintervention was 237 (354) days. The 30-day, 1-year, and 5-year freedom from branch intervention was 98% (95% confidence interval [CI], 96%-99%), 94% (95% CI, 92%-96%), and 84% (95% CI, 78%-90%), respectively. Death from branch stent complications occurred in three patients, two related to SMA thrombosis and one due to an unstented SMA scallop. Multivariable analysis revealed no factors as independent predictors of need for branch reintervention. CONCLUSIONS Branches, after branched or fenestrated aortic repair, appear to be durable and are rarely the cause of patient death. The absence of long-term data on branch patency in open repair precludes comparison, yet the lower morbidity and mortality risk coupled with longer-term durability data will further alter the balance of repair options.

Endovascular repair of complicated chronic distal aortic dissections: Intermediate outcomes and complications

INTRODUCTION Patients with chronic distal aortic dissection (CDAD) remain at high risk for late aorta-related events and reinterventions, and the ideal management strategy remains undefined. Open surgical procedures carry morbidity, but scant data for thoracic endovascular aortic repair (TEVAR) of CDAD exist. This study reports our intermediate-term results with TEVAR for complicated CDAD. METHODS All cases of TEVAR for complicated (aortic growth, malperfusion, intractable pain) CDAD at our institution between 2000 and 2007 were retrospectively reviewed. Demographic information, indications for repair, complications, and aortic morphologic changes were collected from medical records and imaging studies. Aortic morphology (aneurysm size, false lumen thrombosis) was assessed at multiple levels with 3-dimensional image analysis techniques. Kaplan-Meier analysis was used to estimate survival, freedom from reintervention, and likelihood of false lumen thrombosis, with log-rank tests used to discriminate between Kaplan-Meier curves. RESULTS In total, 144 stent-grafts were implanted in 76 consecutive patients (49 male) with complicated CDAD. Early (<30 postoperative days) mortality was 5%. There was no paraplegia, and 1 patient died of stroke. At mean follow-up of 34 months, 12 patients had died (1 aorta-related death). Seventeen patients (22%) underwent 19 secondary aortic reinterventions, mainly for enlargement of the untreated aorta remote to stent-graft repair. Three secondary procedures treated retrograde proximal dissections. Estimated survivals were 86%, 82%, and 80% at 12, 24, and 36 months, respectively, and freedoms from both death and reintervention were 72%, 64%, and 59% at similar time points. Of 67 patients (88%) with complete imaging follow-up, TEVAR resulted in significantly decreased aortic diameter through the stent-grafted segment but not untreated segments. Complete thrombosis of the entire false lumen was uncommon in patients with extensive dissections (13% vs 78% P < .001). CONCLUSIONS Management of complicated CDAD remains challenging for clinicians. TEVAR is a reasonable treatment modality for dissections limited to the thoracic aorta and for prevention of focal aortic growth in extensive dissections. Late complications and the need for secondary interventions emphasize the complexity of this patient population and the need for long-term follow-up.

Long-term follow-up of type II endoleak embolization reveals the need for close surveillance

OBJECTIVE Aneurysm growth after endovascular aneurysm repair (EVAR) in patients with type II endoleak is associated with adverse outcomes. This study evaluated the long-term success of embolization of type II endoleaks in preventing aneurysm sac growth. METHODS We retrospectively reviewed outcomes of patients who underwent infrarenal EVAR who were treated for a type II endoleak between 2000 and 2008. Computed tomography scans were evaluated for aneurysm sac growth or shrinkage from the time of treatment of the endoleak. The embolization material used, graft type, target vessel embolized, and comorbidities were evaluated for their association with sac growth or shrinkage. RESULTS Ninety-five patients underwent 140 embolization procedures. The mean time from EVAR to embolization was 26.1 ± 22.2 months, and the average increase in size of the aneurysm sac from EVAR to treatment was 0.7 × 0.5 cm. Patients underwent an average of 1.6 ± 0.8 embolization procedures after EVAR. Thirteen patients underwent initial simultaneous embolization of two targets. Embolization was with glue (61%), coils (29%), glue and coils (7%), and Gelfoam (3%; Pfizer Inc, New York, NY). No abdominal aortic aneurysms (AAA) ruptured. Eight patients (8.4%) underwent graft explant and open repair; 19 (20%) required two or more embolization procedures. There was no difference in the target vessel treated or the treatment used in halting sac expansion (>5 mm). Coil embolization alone resulted in more second procedures. The 5-year cumulative survival was 65% (95% confidence interval [CI], 52%-77%), freedom from explant was 89% (95% CI, 81%-97%), freedom from second embolization was 76% (95% CI, 66%-86%), and freedom from sac expansion >5 mm was 44% (95% CI 30%-50%). Univariable analysis identified continued tobacco use (hazard ratio [HR], 2.30; 95% CI, 1.02-5.13; P = .04) was associated with continued sac expansion, and hyperlipidemia (HR, 9.64; 95% CI, 2.22-41.86) was associated with patients requiring a second embolization procedure. CONCLUSIONS Embolization of type II endoleaks is successful early in preventing aneurysm sac growth and rupture after EVAR. However, a significant number of patients require more than one procedure, and at 5 years, many patients who underwent embolization of a type II endoleak continued to experience sac growth. Patients with hyperlipidemia who undergo coil embolization are more likely to require a second embolization procedure, and patients who smoke have a higher likelihood of AAA sac expansion after embolization. Continued long-term surveillance is necessary in this cohort of patients.

Revised duplex criteria and outcomes for renal stents and stent grafts following endovascular repair of juxtarenal and thoracoabdominal aneurysms

OBJECTIVES To assess outcomes and develop duplex scan criteria that will reliably determine the luminal status of covered and uncovered renal stents following fenestrated and branched endovascular repair. METHODS A prospective database of patients treated with fenestrated and branched endografts between 2001 and 2006 was reviewed. All patients with evidence of renal artery pathology including duplex scan assessed peak systolic velocity (PSV) <50 or >200 cm/s, renal aortic ratio (RAR) >3.5, elevation of the serum creatinine >30%, computed tomography (CT) evidence of renal stenosis underwent further analyses including medical chart review, and a review of CT and duplex scan imaging data. Correlations of ultrasound scan, CT, angiographic, and clinical outcomes were conducted and receiver operator curve (ROC) analysis was performed. Freedom from stenosis or occlusion was determined by Kaplan-Meier analysis with differences assessed by log rank tests. RESULTS A total of 518 renal arteries were treated with uncovered or covered renal stents (287 patients). Mean follow-up was 25 months. The estimated freedom from stenosis at 12, 24, and 36 months were 95% (95% confidence interval [CI] 93-98), 92% (89-96), and 89% (85-93) for uncovered stents, and 98% (96-100), 97% (95-100), and 95% (91-100) for covered stents (log rank P = .04). Secondary interventions were performed in 20% of the patients who developed stenoses. Only one of the detected stenoses that was not treated with a secondary intervention progressed to occlusion. Duplex scan criteria derived from ROC analysis correlating with curved planar reconstruction (CPR) from axial imaging data calculated a 60-99% in-stent stenosis to be associated with a PSV >280 cm/s or RAR >4.5. Occlusions were best identified by a mid renal artery PSV <57 cm/s in conjunction with an RAR <1.2. CONCLUSION Revised ultrasound scan criteria have been developed to improve the sensitivity and specificity of non-invasive interrogation of renal stents following endovascular aneurysm repair (EVAR). Covered renal stents are associated with a lower incidence of in-stent stenosis and are thus recommended over uncovered stents for use in fenestrated or branched endografts.

Global experience with an inner branched arch endograft.

BACKGROUND Branched endografts are a new option to treat arch aneurysm in high-risk patients. METHODS AND RESULTS We performed a retrospective multicenter analysis of all patients with arch aneurysms treated with a new branched endograft designed with 2 inner branches to perfuse the supra aortic trunks. Thirty-eight patients were included. The median age was 71 years (range, 64-74 years). An American Society of Anesthesiologists score of 3 or 4 was reported in 89.5% (95% confidence interval [CI], 79.7-99.3) of patients. The 30-day mortality rate was 13.2% (95% CI, 2.2-24.2). Technical success was obtained in 32 patients (84.2% [95% CI, 72.4-95.9]). Early secondary procedures were performed in 4 patients (10.5% [95% CI, 0.7-20.3]). Early cerebrovascular complications were diagnosed in 6 patients (15.8% [95% CI, 4.0-27.6]), including 4 transient ischemic attacks, 1 stroke, and 1 subarachnoid hemorrhage. The median follow-up was 12 months (range, 6-12 months). During follow-up, no aneurysm-related death was detected. Secondary procedures during follow-up were performed in 3 patients (9.1% [95% CI, 0.0-19.1]), including 1 conversion to open surgery. We compared the first 10 patients (early experience group) with the subsequent 28 patients. Intraoperative complications and secondary procedures were significantly higher in the early experience group. Although not statistically significant, the early mortality was higher in the early experience group (30% [95% CI, 0.0-60.0]) versus the remainder (7.1% [95% CI, 0.0-16.9]; P=.066). Being part of the early experience group and ascending aortic diameter≥38 mm were found to be associated to higher rates of combined early mortality and neurologic complications. CONCLUSIONS Our preliminary study confirms the feasibility and safety of the endovascular repair of arch aneurysms in selected patients who may not have other conventional options. CLINICAL TRIAL REGISTRATION INFORMATION Thoracic IDE NCT00583817, FDA IDE# 000101.

Twelve-year results of fenestrated endografts for juxtarenal and group IV thoracoabdominal aneurysms

OBJECTIVE The practice of using fenestrated endografts to treat juxtarenal and group IV thoracoabdominal aortic aneurysms (TAAAs) has become more accepted, but long-term outcomes are still unknown. We report long-term survival, complications, and branch-related outcomes from a single-center experience. METHODS The study included consecutive patients enrolled prospectively into a physician-sponsored investigational device exemption classified as undergoing group IV TAAA or juxtarenal aneurysm repair by the treating surgeon using fenestrated endografts. Device morphology was used to subclassify this group of patients. Long-term survival and a composite outcome of secondary intervention, branch occlusion, stent migration, endoleak, aneurysm growth, or spinal cord injury were calculated. Descriptive analysis of branch-related outcomes and need for any reintervention was performed. Univariate and multivariate analysis of mortality and the composite outcome was performed to determine associative risks. RESULTS Long-term survival for patients with juxtarenal and group IV TAAA aneurysms treated with fenestrated stent grafts was 20% at 8 years. Multivariate analysis showed long-term survival for this patient population was negatively associated with increasing age, congestive heart failure, cancer, and previous aneurysm repair. The risk of spinal cord ischemia (SCI) in this group was 1.2% and of aortic-related mortality was 2%. The risk of a spinal event increased with coverage above the celiac artery (52 mm of coverage above the celiac artery in patients with SCI vs 33 mm without SCI; P = .099). More complex device configurations were more likely to require an increased rate of reinterventions, and patients with celiac fenestrations were more likely to experience celiac occlusion over time (3.5% vs 0.5%; P = .019). However, less complex designs were complicated by an increased risk of type I endoleak over time (10.4% for renal fenestrations only vs 1.9% for others; P < .01). As experience evolved, there was a trend to increase the number of fenestrations in devices treating the same anatomy. CONCLUSIONS The use of fenestrated devices to treat juxtarenal and group IV TAAA is safe and effective in long-term follow-up. Mortality in this patient population is largely not aortic-related. Devices designed for fenestrated repair of juxtarenal and group IV thoracoabdominal aneurysms within a physician sponsored investigational device exemption have changed over time. Further research is needed to determine the best configuration to treat aneurysms requiring coverage proximal to the celiac artery.

Pilot study of the accuracy of bedside glucometry in the intensive care unit

Objective To evaluate the accuracy of bedside glucometry among critically ill patients. Design Prospective audit, with sequential specimen collection. Setting Thirty-two-bed cardiovascular, neurosurgical, and medical-surgical intensive care unit in a single Canadian center. Patients Ten critically ill adults, who were sequentially followed during their intensive care unit stay. Eight had diabetes mellitus, and three were in shock. Measurements and Main Results Repeat arterial blood samples were obtained by the attending nurse, who withdrew a portion of the sample and performed reflectance glucometry at the bedside. The remainder was immediately sent in a vacuum-sealed plasma separation tube to the hospital laboratory, and analyzed using a conventional plasma glucose analyzer by a laboratory technologist. Sequential samples were taken at intervals of at least 12 hrs of one other. A total of 105 arterial glucose pairs were obtained. There was a significant correlation between the laboratory and glucometry determined glucose concentrations (intraclass correlation coefficient = 0.86, p < .0001). The overall average laboratory-glucometry glucose difference was −0.04 mmol/L (95% confidence interval [CI] −2.3–2.2 mmol/L). Five out of 105 values (4.8%) lay beyond these confidence bounds. The square of the Pearson correlation coefficient (r2) between the mean glucose level and the laboratory-glucometry glucose difference was not significant (0.01, 95% CI 0.005–0.04;p = .22), suggesting the absence of any trend between rising glucose concentration and the laboratory-glucometry difference. Conclusions Bedside glucose testing of arterial whole blood samples may be an accurate alternative to laboratory plasma glucose measurement among critically ill adults, within approximately 2.3 mmol/L of certainty. Because previous studies have suggested that this bedside technique may be prone to a moderate degree of error among patients in shock as well as those with an abnormal blood pH or hematocrit, larger studies are needed to confirm our findings.

Hypogastric and subclavian artery patency affects onset and recovery of spinal cord ischemia associated with aortic endografting.

OBJECTIVE Spinal cord ischemia (SCI) is a devastating complication associated with aortic aneurysm repair. The aim of the current study was to evaluate factors affecting outcomes from SCI associated with endovascular aortic aneurysm repair. METHODS A total of 1251 patients underwent endovascular repair of aortic aneurysm as part of a device trial between 1998 and 2010 utilizing endovascular abdominal aortic aneurysm repair (n = 351), thoracic endovascular aortic aneurysm repair (n = 201), fenestrated endovascular aortic aneurysm repair (n = 227), and visceral branched endografts (n = 472). Records and imaging studies were reviewed to supplement prospective outcome data. Demographics, type of repair, collateral bed (hypogastric/subclavian) patency, clinical presentation, and outcomes were evaluated on patients with SCI. Survival was calculated using life-table analysis. RESULTS SCI occurred in 2.8% (n = 36) of patients: abdominal aortic aneurysm, 0.3%, juxtarenal, 0.4%, thoracic aortic aneurysm, 4.6%, and thoracoabdominal aortic aneurysm, 4.8%). Four (11%) required carotid-subclavian bypass prior to endografting, and two underwent coverage of the left subclavian artery. Unilateral hypogastric artery occlusion was present in 11 (31%) patients prior to endograft placement, and three had bilateral occlusions. An additional seven patients had occlusion of at least one hypogastric artery during surgery. SCI was apparent immediately in 15 (42%) patients. Immediate onset of symptoms was observed in 73% of patients with at least one occluded collateral bed but in only 24% of those with patent collateral beds (P = .021). Of those presenting in a delayed fashion, nine (43%) had a clear precipitating event prior to onset of SCI (hypotension, n = 6, and segmental artery drain removal, n = 3). Recovery occurred in 24 (67%) patients, most within 7 days. Immediate presentation was a negative predictor of recovery (P = .025), as was occlusion of at least one collateral bed (P = .035). Mean follow-up was 22 ± 4 months with 30-day and 1-year survival of 92 ± 4.6% and 56 ± 8.3%. Survival was only 36% at 3 months in those with permanent SCI compared with 92% (P < .001) in those with temporary symptoms. CONCLUSIONS SCI continues to complicate aortic surgery despite the advent of endovascular therapy. Occlusion of a single collateral bed is associated with an increased risk for immediate onset of SCI and lack of recovery. These factors are harbingers of poor outcomes and increased short-term mortality. This may be prevented by preserving collateral bed patency in patients undergoing extensive endovascular procedures.