Progress and Future Challenges in Thoracoabdominal Aortic Aneurysm Management

Open Treatments for Thoracoabdominal Aortic Aneurysm Repair

Thoracoabdominal aortic aneurysms (TAAA) represent a unique pathology that is associated with considerable mortality if untreated. While the advent of endovascular technologies has introduced new modalities for consideration, the mainstay of TAAA treatment remains open surgical repair. However, the optimal conduct of open TAAA repair requires careful consideration of patient risk factors and a collaborative team effort to mitigate the risk of perioperative complications. In this chapter, we briefly outline the history of treating TAAA, preoperative preparation and postoperative care, and our operative techniques for treatment.

Systematic Review and Patient-Level Meta-analysis of the Streamliner Multilayer Flow Modulator in the Management of Complex Thoracoabdominal Aortic Pathology

Purpose:

To examine the safety and short-term efficacy of the Streamliner Multilayer Flow Modulator (SMFM) in the management of patients with complex thoracoabdominal aortic pathology who are unfit for alternative interventions.

Methods:

Biomedical databases were systematically searched for articles published between 2008 and 2015 on the SMFM. A patient-level meta-analysis was used to evaluate aneurysm-related survival. Secondary outcomes were all-cause survival, stroke, spinal cord ischemia, renal impairment, and branch vessel patency. Other considerations were the impact of compliance with the instructions for use (IFU) on clinical outcome. Mean values and Kaplan-Meier estimates are presented with the 95% confidence interval (CI).

Results:

Fifteen articles (3 multicenter cohort studies, 3 observational cohort studies, and 9 case reports) were included, presenting 171 patients (mean age 68.8±12.3 years; 139 men). The mean aneurysm diameter was 6.7±1.6 cm (95% CI 6.4 to 6.9 cm). Technical success reported in 15 studies was 77.2%. Aneurysm-related survival at 1 year was 78.7% (95% CI 71.7% to 84.4%). One-year all-cause survival was 53.7% (95% CI 46.0% to 61.3%). There were no reported cases of spinal cord ischemia, renal insult, or stroke.

Conclusion:

The SMFM can be safely utilized in some patients with complex thoracoabdominal pathologies provided operators adhere to the IFU. The SMFM is a novel technology with no long-term published data on its sustained effectiveness and a lack of comparative studies. Randomized clinical trials, registries, and continued assessment are essential before this flow-modulating technology can be widely disseminated.

A novel endovascular debranching technique using physician-assembled endografts for repair of thoracoabdominal aneurysms

OBJECTIVE

The objective of this study was to demonstrate a technique that uses physician-assembled endografts to make use of the benefits of parallel grafts while also providing for circumferential seal and fixation in repair of thoracoabdominal aneurysms in inoperable patients.

METHODS

A single-center all-comers retrospective analysis of 14 patients was performed that looked at the early outcomes of patients treated for thoracoabdominal aneurysms. Three Crawford type II, four type III, four type IV, and three type V thoracoabdominal aneurysms were treated. Contrast material, fluoroscopy time, length of stay, clinical success, and technical success were measured.

RESULTS

There was no in-hospital, 30-day, or 6-month mortality. We found two type III endoleaks in the early design. One required coil embolization. Average volume of contrast material and average fluoroscopy time were 76.9 mL and 119.1 minutes, respectively. Average length of stay was 10.5 days, and average procedure time was 251.2 minutes. Clinical success was observed in 78.6% of patients to date, and technical success was observed in 85.7% of patients.

CONCLUSIONS

Short-term results show that this approach is safe. The device can be safely implanted, is off-the-shelf, and can treat each of the Crawford thoracoabdominal aneurysm types. Finally, the assembly of off-the-shelf components may shorten the regulatory path for this physician-assembled endograft.

Mid-term results of elective repair of extensive thoracic aortic pathology by the Evita Open Plus hybrid endoprosthesis only

OBJECTIVES

To describe the early and mid-term clinical and instrumental results of the frozen elephant trunk (FET) procedure using the recent Evita Open Plus hybrid endoprosthesis for elective one-stage treatment of extensive thoracic aortic disease.

METHODS

We reviewed 16 patients undergoing FET for post-dissection aneurysm (50%), true aneurysm (31%) or other aetiologies (19%), through median sternotomy and hypothermic circulatory arrest. An average 14 ± 7.6-month follow-up with regular contrast-enhanced control computed tomography scans was available. Four patients received preliminary carotid-subclavian bypass to improve spinal cord protection. Distal extension through endovascular deployment of stent-grafts into the descending aorta was performed during the same procedure in 3 patients. Concomitant procedures on the ascending aorta/root were done in 25% of cases.

RESULTS

There were no cases of operative mortality. Cases of neither cerebral stroke nor postoperative paraplegia were observed. Two cases of transient paraparesis and 1 case of Brown-Séquard syndrome occurred. At follow-up, there were no cases of endoleak or endotension. One patient was reoperated for distal completion (thoracoabdominal aortic replacement).

CONCLUSIONS

The FET using the Evita Open Plus device is a reliable and versatile treatment for one-step management of extensive disease of the aortic arch and the descending aorta. This strategy should be reserved for patients having limited preoperative comorbidities and good functional status.

Distal aortic perfusion during thoracoabdominal aneurysm repair for prevention of paraplegia

BACKGROUND

During thoracoabdominal aortic aneurysm (TAAA) surgery, decreased spinal cord perfusion can result in neurological deficits such as paraplegia and paraparesis. Distal aortic perfusion, alone or in combination with other adjuncts, may counter the decrease in spinal cord perfusion and hence reduce the risk of spinal cord injury.

OBJECTIVES

To determine the effectiveness of distal aortic perfusion with or without other adjuncts against other adjuncts without use of distal perfusion during TAAA surgery in reducing the risk of developing paraplegia and paraparesis.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched 5 January 2012) and CENTRAL (Issue 4, 2011) were searched for publications describing randomised controlled trials of distal aortic perfusion during thoracoabdominal aortic aneurysm surgery. Reference lists of relevant studies were checked.

SELECTION CRITERIA

Randomised or quasi-randomised controlled clinical trials of distal aortic perfusion during TAAA repair.

DATA COLLECTION AND ANALYSIS

Studies identified for potential inclusion were independently assessed for inclusion by at least two authors, with excluded trials arbitrated by the third author.

MAIN RESULTS

There were no randomised controlled trials identified.

AUTHORS' CONCLUSIONS

Currently, there are no randomised controlled trials to support the role of distal aortic perfusion in TAAA surgery for prevention of neurological injury. However, randomised controlled trials are not always feasible based on ethical grounds. Observational studies suggest that distal aortic perfusion alone or in combination with other adjuncts, that is cerebrospinal fluid (CSF) drainage, reduces the rate of neurologic deficit across all types of TAAA; in particular making a striking difference in the rate of neurologic deficit following type II TAAA repair. In the absence of randomised controlled trials, we recommend a standardised approach to reporting through registry studies to strengthen the evidence base for distal aortic perfusion.

Continued favorable results with open surgical repair of type IV thoracoabdominal aortic aneurysms

OBJECTIVES

Type IV thoracoabdominal aortic aneurysm (TAAA) repair, despite low risk of spinal cord ischemia (SCI), is reported to have significant morbidity and mortality. This has led some to apply adjuncts (eg, extracorporeal circulation) used in more extensive TAAA repair or to consider alternative approaches, such as hybrid operations. We have used a consistent, simplified surgical approach to type IV TAAA, and the goal of the present study is to review experience over 2 decades with such treatment and to identify correlates of surgical morbidity.

METHODS

All type IV repairs at Massachusetts General Hospital from January 1989 through September 2009 were evaluated for clinical features, technical operative details, and 30-day outcomes. Logistic regression identified predictors of morbidity. Survival was assessed using Kaplan-Meier analysis.

RESULTS

A total of 179 patients underwent type IV repair, with elective repair in 156 (87%) and urgent in 23 (13%). The clamp-and-sew technique was used for all operations, with routine hypothermic renal perfusion. Clinical features were age 73 ± 8 years, coronary artery disease in 89 (50%), and creatinine level >1.8 mg/dL defining chronic renal insufficiency (CRI) in 32 (18%). Operative reconstruction in 166 (93%) consisted of one beveled proximal anastomosis incorporating the descending thoracic aorta, celiac, superior mesenteric artery, and right renal arteries origins (mean visceral clamp time, 36 ± 12 minutes) and a side-arm graft to the left renal artery. Technical details included previous abdominal aortic aneurysm (AAA) repair in 52 (29%), operative time of 290 ± 90 min, estimated blood loss of 2.7 ± 1.4 L, and splenectomy in 57 (32%). The 30-day outcomes were death in 5 (2.8%), myocardial infarction in 6 (3.4%), hemodialysis in 5 (2.8%), and any degree of SCI in 4 (2.2%). Regression analysis identified a history of CRI as an independent predictor of postoperative complication or death (odds ratio, 3.4; 95% confidence interval, 1.4-8). Survival rates at 1, 5, and 10 years were 89% ± 2%, 62% ± 4%, and 36% ± 5%, respectively.

CONCLUSIONS

A simplified operative approach for type IV TAAA repair is associated with favorable perioperative results. These data refute the need for surgical adjuncts commonly applied in more extensive TAAA and indicate that the hybrid operation is an illogical posture. CRI should figure prominently in clinical decision making. Long-term survival equates that observed after routine AAA repair.

Endovascular treatment of thoracoabdominal aneurysm

OPINION STATEMENT

The use of endovascular modalities for the treatment of simple descending thoracic aneurysms has become standard of care. Expanding endovascular techniques for the treatment of thoracoabdominal aneurysms is now possible with the evolution of branched and fenestrated grafts.