Prospective randomized pilot trial comparing prophylactic vs therapeutic cerebrospinal fluid drainage during complex endovascular thoracoabdominal aortic aneurysm repair

BACKGROUND

Endovascular techniques have transformed the management of thoracoabdominal aortic aneurysms (TAAAs). However, spinal cord ischemia (SCI) remains a prevalent and devastating complication. Prophylactic drainage of cerebrospinal fluid (CSF) is among the proposed strategies for prevention of SCI. Although prophylactic CSF drainage is widely used and conceptually attractive, prophylactic CSF drains have not been demonstrated to definitively prevent the occurrence nor mitigate the severity of SCI in endovascular TAAA repair. Whether or not outcomes of prophylactic drains are superior to therapeutic drains remains unknown. This pilot study was performed to determine the feasibility of a randomized clinical trial designed to investigate the role of prophylactic vs therapeutic CSF drains in the prevention of SCI in patients undergoing endovascular TAAA repair using branched and fenestrated endovascular aortic repair (FBEVAR).

METHODS

This was a prospective multicenter randomized pilot clinical trial conducted at The University of Alabama at Birmingham and The University of Massachusetts. Twenty patients were enrolled and randomized to either the prophylactic drainage or therapeutic drainage groups, prior to undergoing FBEVAR for extensive TAAAs and arch aortic aneurysms. This was a pilot feasibility study that was not powered to detect statistical differences in clinical outcomes. The primary outcome was feasibility of randomization and compliance with a shared lumbar drain protocol. Secondary outcomes included rate of drain complications and SCI.

RESULTS

Twenty patients were enrolled and successfully randomized, without any crossovers, to either the control cohort (n = 10), without prophylactic drains, or the experimental cohort (n = 10), with prophylactic drains. There were no differences in age, comorbidities, or history of prior aortic surgery across the cohorts. All patients were treated with FBEVAR. Aneurysm classifications were as follows: Extent I (10%), Extent II (50%), Extent III (35%), and Extent IV (5%). The average length of aortic coverage was 207 ± 21.6 mm. The length of aortic coverage did not vary across cohorts, nor did procedural times or blood loss volume. Compliance with the SCI prevention protocol was 100% across both groups. Within the prophylactic drain cohort, one patient experienced an adverse event related to lumbar drain placement, manifested as an epidural hematoma requiring laminectomy, without neurologic deficit (n = 1/10; 10%). There was one SCI event (n = 1/20; 5%), which occurred in the prophylactic drain cohort on postoperative day 9 following an episode of hypotension related to a gastrointestinal bleed.

CONCLUSIONS

The role of prophylactic CSF drains for the prevention of SCI following endovascular TAAA repair is a topic of ongoing research, with many current practices based on expert opinion and experience, rather than rigorous scientific data. This study demonstrates the feasibility of a multicenter randomized clinical trial to evaluate the role of prophylactic vs therapeutic CSF drains in the prevention of SCI in patients undergoing endovascular TAAA repair.

Assessment of aortic hemodynamics in patients with thoracoabdominal aortic aneurysm using four-dimensional magnetic resonance imaging: a cross-sectional study

Background

Thoracoabdominal aortic aneurysms (TAAAs) are rare but complicated aortic pathologies that can result in high morbidity and mortality. The whole-aorta hemodynamic characteristics of TAAA survivors remains unknown. This study sought to obtain a comprehensive view of flow hemodynamics of the whole aorta in patients with TAAA using four-dimensional flow (4D flow) magnetic resonance imaging (MRI).

Methods

This study included patients who had experienced TAAA or abdominal aortic aneurysm (AAA) and age- and sex-matched volunteers who had attended China Hospital from December 2021 to December 2022 in West. Patients with unstable ruptured aneurysm or other cardiovascular diseases were excluded. 4D-flow MRI that covered the whole aorta was acquired. Both planar parameters [(regurgitation fraction (RF), peak systolic velocity (Vmax), overall wall shear stress (WSS)] and segmental parameters [pulse wave velocity (PWV) and viscous energy loss (VEL)] were generated during postprocessing. The Student's t-test or Mann-Whitney test was used to compare flow dynamics among the three groups.

Results

A total of 11 patients with TAAA (mean age 53.2±11.9 years; 10 males), 19 patients with AAA (mean age 58.0±11.7 years; 16 males), and 21 controls (mean age 55.4±15.0 years; 19 males) were analyzed. The patients with TAAA demonstrated a significantly higher RF and lower Vmax in the aortic arch compared to healthy controls. The whole length of the aorta in patients with TAAA was characterized by lower WSS, predominantly in the planes of pulmonary artery bifurcation and the middle infrarenal planes (all P values <0.001). As for segmental hemodynamics, compared to controls, patients with TAAA had a significantly higher PWV in the thoracic aorta (TAAA: median 11.41 m/s, IQR 9.56-14.32 m/s; control: median 7.21 m/s, IQR 5.57-7.79 m/s; P<0.001) as did those with AAA (AAA: median 8.75 m/s, IQR 7.35-10.75 m/s; control: median 7.21 m/s, IQR 5.57-7.79 m/s; P=0.024). Moreover, a greater VEL was observed in the whole aorta and abdominal aorta in patients with TAAA.

Conclusions

Patients with TAAA exhibited a stiffer aortic wall with a lower WSS and a greater VEL for the whole aorta, which was accompanied by a higher RF and lower peak velocity in the dilated portion of the aorta.

Open and endovascular repair of thoracoabdominal aortic aneurysm-a narrative review

BACKGROUND AND OBJECTIVE

Thoracoabdominal aortic aneurysms (TAAAs) are associated with a high rate of morbidity and mortality when left untreated, yet their repair has been associated considerable risk as well. We aim to present a review of the epidemiology, risk factors, pathophysiology, natural history, management strategies, and current literature on open and endovascular repair of thoracoabdominal aortic aneurysms.

METHODS

A narrative review using current search of the most recent literature on this topic.

KEY CONTENT AND FINDINGS

Indication for surgical repair includes symptomatic aneurysms and those at a size or growth threshold. Open repair is the gold standard for surgical management of TAAA and remains so, however, endovascular repair has an increasingly broad applicability, and technology has correspondingly improved in the two decades since its introduction to clinical practice. Reported contemporary operative mortality has ranged from less than 5% to over 20%. The primary adverse complication of open and endovascular repair is ischemic injury, including renal injury, with reported incidence ranging from 2.8-12.5% in contemporary series, and spinal cord injury, with reported incidence ranging from 2.5% to 7.3% in contemporary series. Cerebrospinal fluid drainage has been shown to be the best-proven mechanism to date to prevent spinal cord injury in both open and endovascular repair.

CONCLUSIONS

Endovascular repair is associated with a higher reintervention rate than open repair. Surgeon and center volume and expertise are related to clinical outcomes and should be taken into consideration when deciding on surgical repair.

Predictors and Outcomes of Spinal Cord Injury following Complex Branched/Fenestrated Endovascular Aortic Repair in the US Aortic Research Consortium

OBJECTIVE

Spinal cord ischemia (SCI) is a well-known complication of thoracoabdominal aortic aneurysm (TAAA) repair and is associated with profound morbidity and mortality. The purpose of this study was to describe predictors for the development of SCI, as well as outcomes for patients who develop SCI, after branched/fenestrated endovascular aortic repair (FB-EVAR) in a large cohort of centers with adjudicated physician-sponsored investigational device exemption studies.

METHODS

We utilized a pooled dataset from 9 United States Aortic Research Consortium (US ARC) centers involved in investigational device exemption (IDE) trials for treatment of suprarenal and thoracoabdominal aortic aneurysms. SCI was defined as new transient weakness (paraparesis) or permanent paraplegia after repair without other potential neurologic etiologies. Multivariable analysis was performed to identify predictors of SCI, and life-table analysis and Kaplan-Meier methodology were used to evaluate survival differences.

RESULTS

A total of 1,681 patients underwent FB-EVAR over the period 2005-2020. The overall rate of SCI was 7.1% (3% transient and 4.1% permanent). Predictors of SCI on multivariable analysis were Crawford Extent I, II, and III distribution of aortic disease (OR 4.79 95% CI 4.77- 4.81, P<.001), age ≥70 (OR 1.64, 95% CI, 1.63-1.64, P=.029), packed red blood cell transfusion (OR 2.00, 95% CI, 1.99-2.00, P=.001), and history of PVD (OR 1.65, 95% CI, 1.64-1.65, P=.034). Median survival was significantly worse for patients with any degree of SCI compared to those without SCI (any SCI - 40.4 vs no SCI - 60.3 months, Log Rank <.001), and also worse in those with a permanent deficit (24.1 months) vs. those with a transient deficit (62.4 months) (Log Rank <0.001). One year survival for patients who developed no SCI was 90.8%, compared to 73.9% in patients who developed any SCI. When stratified by degree of deficit, survival was 84.8% at one year for those who developed paraparesis, and 66.2% for those who developed permanent deficits.

CONCLUSIONS

The overall rates of any SCI at 7.1% and permanent deficit at 4.1% observed in this study compare favorably to those reported in contemporary literature. Our findings confirm that increased length of aortic disease is associated with SCI and those with Crawford Extent I-III TAAAs are at highest risk. The long-term impact on patient mortality underscores the importance of preventive measures and rapid implementation of rescue protocols if and when deficits develop.

Short-term effectiveness and safety of an anatomy-conforming hybrid surgery protocol for thoracoabdominal aortic aneurysms

BACKGROUND

Thoracoabdominal aortic aneurysms (TAAAs) are one of the most complex aortic aneurysms to treat. Traditional open surgery for TAAAs is highly invasive and total endovascular treatment still has many limitations. Hybrid surgery offers a viable option for TAAA patients, but currently it often alters the original hemodynamics. Therefore, we have developed and applied a hybrid surgery protocol for anatomically suitable TAAA patients. Here we analyzed the short-term outcomes of these patients and evaluated the effectiveness and safety of this procedure.

METHODS

A new method was used to perform the required artificial revascularization of the abdominal aorta and its branches. A new visceral debranching and reconstruction approach was used to complete an anatomy-conforming open surgery. Finally, a new vascular access was used for the endovascular operation to complete the implantation of stent-grafts. The clinical data of 10 patients with TAAAs treated at our center with the anatomy-conforming hybrid technique during the period from May 2018 to June 2020 was retrospectively analyzed. The intraoperative and 30-day postoperative key indicators, including survival rates and complications, were analyzed.

RESULTS

The hybrid surgery was smoothly performed in all 10 patients. One patient died from non-aortic causes (sepsis/infectious toxic shock) 30 days after surgery, yielding a case-fatality rate of 10.0% (1/10). Two patients (2/10) experienced serious complications within 30 days postoperatively, including multi-organ failure due to infection in one patient and lower limb ischemia in another patient who went on to develop permanent paraplegia. No endoleak after stent implantation was noted and the blood supply of each reconstructed visceral artery was good.

CONCLUSIONS

Based on the short-term outcomes, the anatomy-conforming hybrid surgical protocol is safe and effective in treating TAAA patients.

Paraspinal muscle claudication after fenestrated-branched endovascular aortic repair of thoracoabdominal aortic aneurysms

Fenestrated-branched endovascular repair of thoracoabdominal aneurysms carries a risk of spinal cord ischemia owing to extensive coverage of intercostal arteries, but other consequences of decreased flow to the paraspinal muscles have not been delineated. We describe a 54-year-old woman treated by multibranched thoracoabdominal aneurysm repair who developed severe disabling exertional thoracic and lumbar back pain after the operation. Despite physical therapy, the patient remains with disabling symptoms at 2 years of follow-up. Transcutaneous oxygen pressures confirmed exercise-induced decrease in oxygen pressure, consistent with decreased muscle perfusion. We propose the term paraspinal muscle claudication to describe these symptoms.

Possible graft-related complications in visceral debranching for hybrid B dissection repair

BACKGROUND

Hybrid repair (HR) of thoracoabdominal aortic aneurysm (TAAA) and dissection (TAAD), consisting of rerouting renovisceral branches followed by endograft aortic repair, has been shown to be a feasible option. It is especially appealing in patients unfit for both open and total endovascular repair. In order to determine the role of dissecting etiology and intraoperative variables as risk factors for graft-related complications in visceral debranching, we retrospectively analyzed the clinical outcomes, patency rate and hemodynamic alterations of the renovisceral debranching grafts in our series.

METHODS

We analyzed 55 consecutive patients who underwent thoracoabdominal aortic HR between 2001 and 2013 in our center. Forty-four procedures were performed for TAAA and 11 procedures for TAAD. In TAAD patients, dissection involved 9/44 (20.5%) renovisceral vessels. One hundred and fifty-nine visceral bypasses were made (156 retrograde; three anterograde).

RESULTS

Thirty-day mortality was 12.7% (n=7). Potential graft-related complications included four cases of pancreatitis (7.3%) and five of peri-operative renal failure (9.1%). At a mean follow-up of 36.1 months, the global rate of visceral graft occlusion was 9.4% (15/159), leading to fatal bowel infarction in two patients and kidney loss in seven patients. Actuarial primary patency in renovisceral grafts at 12, 24, and 36 months was 96.3%, 92.6%, and 90.2% respectively. At the level of the anastomosis of the graft to the superior mesenteric artery, significant flow alterations (systolic peak velocity >250 cm/s) were observed during computed flow dynamics analysis in 18.5% of cases. Overall, an additional procedure to ensure patency was required in 19 bypasses intraoperatively and three during follow-up. The presence of aortic dissection had no significant impact on debranching graft-related complications. During multivariate analysis, retropancreatic routing to CT was the only independent predictor of graft-related complications (P=0.006).

CONCLUSIONS

Specific visceral graft-related complications were not uncommon in our series and were often associated with clinical consequences. Hemodynamic alterations of debranching grafts were observed in particular at the level of the anastomosis with the superior mesenteric artery. Careful follow-up is mandatory in order to monitor visceral bypasses and facilitate patency when required.

Video-atlas of hybrid thoracoabdominal aortic aneurysm repair

Although open surgical repair of thoracoabdominal aortic aneurysm (TAAA) has evolved significantly over the last few decades, technical challenges and current morbidity and mortality of the inclusion technique are still significant, particularly in patients with extensive aneurysms or prior aortic surgery and in poor surgical candidates. Hybrid TAAA repair is an appealing technique and may represent a "bridge" solution as we wait for larger series and reproducible results from the evolving experience with total endovascular TAAA repair with fenestrated and branched endografts.