Have thoracic endografting outcomes improved since US Food and Drug Administration approval?

A Dual-VENC Four-Dimensional Flow MRI Framework for Analysis of Subject-Specific Heterogeneous Nonlinear Vessel Deformation

Advancement of subject-specific in silico medicine requires new imaging protocols tailored to specific anatomical features, paired with new constitutive model development based on structure/function relationships. In this study, we develop a new dual-velocity encoding coefficient (VENC) 4D flow MRI protocol that provides unprecedented spatial and temporal resolution of in vivo aortic deformation. All previous dual-VENC 4D flow MRI studies in the literature focus on an isolated segment of the aorta, which fail to capture the full spectrum of aortic heterogeneity that exists along the vessel length. The imaging protocol developed provides high sensitivity to all blood flow velocities throughout the entire cardiac cycle, overcoming the challenge of accurately measuring the highly unsteady nonuniform flow field in the aorta. Cross-sectional area change, volumetric flow rate, and compliance are observed to decrease with distance from the heart, while pulse wave velocity (PWV) is observed to increase. A nonlinear aortic lumen pressure-area relationship is observed throughout the aorta such that a high vessel compliance occurs during diastole, and a low vessel compliance occurs during systole. This suggests that a single value of compliance may not accurately represent vessel behavior during a cardiac cycle in vivo. This high-resolution MRI data provide key information on the spatial variation in nonlinear aortic compliance, which can significantly advance the state-of-the-art of in-silico diagnostic techniques for the human aorta.

A rare case of fatal multi-organ polymer graft material and cholesterol embolization following aortic repair

Ischemia is a common complication of various endovascular procedures including endovascular aortic aneurysm repair. Multiple mechanisms can contribute to the pathogenesis of ischemia: thrombosis, arterial dissection, graft malpositioning, cholesterol embolization, and polymer graft embolization which is an underrecognized complication. To the best of our knowledge, only 38 cases of polymer graft embolization have been reported in the literature. The phenomenon has been reported in different organs including brain, heart, lungs, kidneys, bowel, liver, and skin. We report a unique case of fatal simultaneous cholesterol and polymer graft embolization with subsequent ischemic infarction of multiple organs (liver, kidneys, spleen, pancreas, duodenum, and stomach) in a 76-year-old woman following endovascular repair for an enlarging thoracic aortic aneurysm.

A nationwide study of treatment modalities for thoracic aortic injury

BACKGROUND

Thoracic aortic injuries have traditionally been associated with high morbidity and mortality. Thoracic endovascular aortic repair has emerged as a suitable alternative to open repair, but its impact at a national level remains ill defined. This study aimed to analyze the national trends of patient characteristics, outcomes, and resource utilization in the treatment of thoracic aortic injuries.

METHODS

Patients admitted with thoracic aortic injuries from 2005-2014 were identified in the National Inpatient Sample. Patients were identified as undergoing thoracic endovascular aortic repair, open surgery, or nonoperative management. The primary outcome was in-hospital mortality, while secondary outcomes included complications and costs. Multivariate regressions accounting for characteristics of the patients and injury characteristics were used to determine predictors of mortality and changes in cost.

RESULTS

Of the 11,257 patients admitted for thoracic aortic injuries, 33% received thoracic endovascular aortic repair, 8% open surgery, and 59% nonoperative management. Thoracic endovascular aortic repair had the great largest growth in case volume (P < .001). Compared to open surgery, thoracic endovascular aortic repair patients had greater rates of concomitant brain (17 vs 26%, P = .01), pulmonary (21 vs 33%, P < .001), and splenic injuries (2 vs 4%, P = .031). In-hospital mortality was greater for open surgery (odds ratio = 3.06, P = .003) and nonoperative management (odds ratio = 4.33, P < .001) than thoracic endovascular aortic repair. Over time, mortality rates for thoracic endovascular aortic repair decreased (P = .002), but increased for open surgery (P = .04). Interestingly, total costs with thoracic endovascular aortic repair increased (P = .004), while they decreased for open surgery (P = .031).

CONCLUSION

Our findings indicate the rapid adoption of thoracic endovascular aortic repair over open surgery for management of thoracic aortic injuries. Thoracic endovascular aortic repair is associated with lower mortality rates, but it has greater costs not otherwise explained by other patient factors.

Complications and Perioperative Management of Patients Undergoing Thoracic Endovascular Aortic Repair

Endovascular treatments have become increasingly common for patients with a variety of thoracic aortic pathologies. Although considered less invasive than traditional open surgical approaches, they are nonetheless complex procedures. Patients undergo manipulation of an often calcified aorta near the origin of the carotid and subclavian vessels and have stents placed in a curved vessel adjacent to a perpetually beating heart. These stents can obstruct blood flow to the spinal cord, induce an inflammatory response, and in rare cases erode into the adjacent trachea or esophagus. Renal complications range from contrast-induced nephropathy to hypotension and ischemia to dissection. Emboli can lead to strokes and mesenteric ischemia. These patients have complex medical histories, and skilled perioperative management is critical to achieving the best clinical outcomes. Here, we review the medical management of the most common complications in these patients including stroke, spinal cord ischemia, renal injury, retrograde dissections, aortoesophageal and aortobronchial fistulas, postimplantation syndrome, mesenteric ischemia, and endograft failure.

Transcaval Aortic Access for Percutaneous Thoracic Aortic Aneurysm Repair: Initial Human Experience

Transcaval aortic access has been used for deployment of transcatheter aortic valves in patients in whom conventional arterial approaches are not feasible. The present report describes its use for thoracic endovascular aortic repair (TEVAR) in a 61-year-old man with a descending thoracic aneurysm. Transcaval access was performed in lieu of a surgical iliac conduit in view of small atherosclerotic pelvic arteries. TEVAR was successfully performed, followed by intervascular tract occlusion with the use of a ventricular septal occluder. Computed tomography 2 d later demonstrated no extravasation. At 1 mo, the aneurysm was free of endoleaks, the aortocaval tract had healed, and the patient had returned to baseline functional status.

The use of fenestrated and branched endovascular aneurysm repair for juxtarenal and thoracoabdominal aneurysms: a systematic review and cost-effectiveness analysis

BACKGROUND

Patients with large abdominal aortic aneurysms (AAAs) are usually offered reparative treatment given the high mortality risk. There is uncertainty about how to treat juxtarenal AAAs (JRAAAs) or thoracoabdominal aortic aneurysms (TAAAs). Endovascular repair of an abdominal aortic aneurysm (EVAR) is often seen as safer and easier than open surgical repair (OSR). However, endovascular treatment of JRAAAs or TAAAs requires specially manufactured stent grafts, with openings to allow blood to reach branches of the aorta. Commissioners are receiving increasing requests for fenestrated EVAR (fEVAR) and branched EVAR (bEVAR), but it is unclear whether or not the extra cost of fEVAR or bEVAR is justified by advantages for patients.

OBJECTIVE(S)

To assess the clinical effectiveness, safety and cost-effectiveness of fEVAR and bEVAR in comparison with conventional treatment (i.e. no surgery) or OSR for two populations: JRAAAs and TAAAs.

DATA SOURCES

Resources were searched from inception to October 2013, including MEDLINE (OvidSP), EMBASE (OvidSP) and the Cochrane Central Register of Controlled Trials (Wiley) and, additionally, for cost-effectiveness, NHS Economic Evaluation Database (NHS EED; Wiley) and EconLit (EBSCOhost). Conference abstracts were also searched.

REVIEW METHODS

Studies were included based on an intervention of either fEVAR or bEVAR and a comparator of either OSR or no surgery. For clinical effectiveness, observational studies were excluded only if they were not comparative, i.e. explicitly selected on the basis of prognosis.

RESULTS

For clinical effectiveness, searches retrieved 5253 records before deduplication. Owing to overlap between the databases, 1985 duplicate records were removed. Of the remaining 3268 records, based on titles and abstracts, 3244 records were excluded, leaving 24 publications to be ordered. All 24 studies were excluded as none of them satisfied the inclusion criteria. Sixteen studies were excluded on study design, six on intervention and two on comparator. Five out of 16 studies excluded on study design reported a comparison. However, all of the studies acknowledged that they had groups that were not comparable at baseline given that they had selectively assigned younger, fitter patients to OSR. Therefore, these studies were considered 'non-comparative'. For cost-effectiveness, searches identified 104 references before deduplication. Owing to overlap between the databases, 34 duplicate records were removed. Of the remaining 70 records, seven were included for the full assessment based on initial screening. After a full-text review, no studies were included. Because of the lack of clinical effectiveness evidence and difficulty in estimating costs given the rapidly changing and variable technology, a cost-effectiveness analysis (CEA) was not performed. Instead a detailed description of modelling methods was provided.

CONCLUSIONS

Despite a thorough search, no studies could be found that met the inclusion criteria. All studies that compared either fEVAR or bEVAR with either OSR or no surgery explicitly selected patients based on prognosis, i.e. essentially the populations for each comparator were not the same. Despite not being able to conduct a CEA, we have provided detailed methods for the conduct if data becomes available.

FUTURE WORK

We recommend at least one clinical trial to provide an unbiased estimate of effect for fEVAR/bEVAR compared with OSR or no surgery. This trial should also collect data for a CEA.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42013006051.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

Cardiac tamponade during thoracic endovascular aortic repair

Thoracic endovascular aortic repair (TEVAR) is still associated with complications which include mortality in 7.3% of cases. In this report, we describe the case of a man with a pseudoaneurysm of the aortic isthmus that was scheduled to undergo endovascular repair. During the procedure, the patient had a sudden cardiac arrest due to a compressive hemopericardium caused by perforation of the ascending aorta. The diagnosis was not clear and was made by transthoracic echocardiography after five minutes of resuscitation. In spite of the evacuation of the hemopericardium and suture of the perforation, the patient died. The diagnosis would have been easier and faster if the patient had been monitored continuously by transesophageal echocardiography during the procedure.

Endovascular repair of type B aortic dissection: long-term results of the randomized investigation of stent grafts in aortic dissection trial

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) represents a therapeutic concept for type B aortic dissection. Long-term outcomes and morphology after TEVAR for uncomplicated dissection are unknown.

METHODS AND RESULTS

A total of 140 patients with stable type B aortic dissection previously randomized to optimal medical treatment and TEVAR (n=72) versus optimal medical treatment alone (n=68) were analyzed retrospectively for aorta-specific, all-cause outcomes, and disease progression using landmark statistical analysis of years 2 to 5 after index procedure. Cox regression was used to compare outcomes between groups; all analyses are based on intention to treat. The risk of all-cause mortality (11.1% versus 19.3%; P=0.13), aorta-specific mortality (6.9% versus 19.3%; P=0.04), and progression (27.0% versus 46.1%; P=0.04) after 5 years was lower with TEVAR than with optimal medical treatment alone. Landmark analysis suggested a benefit of TEVAR for all end points between 2 and 5 years; for example, for all-cause mortality (0% versus 16.9%; P=0.0003), aorta-specific mortality (0% versus 16.9%; P=0.0005), and for progression (4.1% versus 28.1%; P=0.004); Landmarking at 1 year and 1 month revealed consistent findings. Both improved survival and less progression of disease at 5 years after elective TEVAR were associated with stent graft induced false lumen thrombosis in 90.6% of cases (P<0.0001).

CONCLUSIONS

In this study of survivors of type B aortic dissection, TEVAR in addition to optimal medical treatment is associated with improved 5-year aorta-specific survival and delayed disease progression. In stable type B dissection with suitable anatomy, preemptive TEVAR should be considered to improve late outcome.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01415804.

Computed tomography angiography of hybrid thoracic endovascular aortic repair of the aortic arch

Endovascular repair of the aorta has traditionally been limited to the abdominal aorta and, more recently, the descending thoracic aorta. However, recently hybrid repairs (a combination of open surgical and endovascular repair) have made endovascular repair of the aortic arch possible. Hybrid repair of the aortic arch typically involves an open surgical debranching procedure that allows for revascularization of the aortic arch vessels and subsequent endovascular stent placement. These approaches avoid the deep hypothermic circulatory arrest required for full, open surgical repair of the aortic arch. In hybrid repairs, the stent landing zone determines which branch vessels will be covered and therefore need revascularization. This article will review the preprocedure assessment with computed tomography angiography, techniques for revascularization and postprocedure complications.

Risk factors for 1-year mortality after thoracic endovascular aortic repair

OBJECTIVE

Thoracic endovascular aortic repair, although physiologically well tolerated, may fail to confer significant survival benefit in some high-risk patients. In an effort to identify patients most likely to benefit from intervention, the present study sought to determine the risk factors for 1-year mortality after thoracic endovascular aortic repair.

METHODS

A retrospective review was performed on prospectively collected data from all patients undergoing thoracic endovascular aortic repair from 2002 to 2010 at a single institution. Univariate analysis and multivariate Cox proportional hazards regression analysis were used to identify risk factors associated with mortality within 1 year after thoracic endovascular aortic repair.

RESULTS

During the study period, 282 patients underwent at least 1 thoracic endovascular aortic repair; index procedures included descending aortic repair (n = 189), hybrid arch repair (n = 55), and hybrid thoracoabdominal repair (n = 38). The 30-day/in-hospital mortality was 7.4% (n = 21) and the overall 1-year mortality was 19% (n = 54). Cardiopulmonary pathologies were the most common cause of nonperioperative 1-year mortality (22%, n = 12). Multivariate modeling demonstrated 3 variables independently associated with 1-year mortality: age older than 75 years (hazard ratio, 2.26; P = .005), aortic diameter greater than 6.5 cm (hazard ratio, 2.20; P = .007), and American Society of Anesthesiologists class 4 (hazard ratio, 1.85; P = .049). A baseline creatinine greater than 1.5 mg/dL (hazard ratio, 1.79; P = .05) and congestive heart failure (hazard ratio, 1.87; P = .08) were also retained in the final model. These 5 variables explained a large proportion of the risk of 1-year mortality (C statistic = 0.74).

CONCLUSIONS

Age older than 75 years, aortic diameter greater than 6.5 cm, and American Society of Anesthesiologists class 4 are independently associated with 1-year mortality after thoracic endovascular aortic repair. These clinical characteristics may help risk-stratify patients undergoing thoracic endovascular aortic repair and identify those unlikely to derive a long-term survival benefit from the procedure.