Japanese perspective in surgery for thoracoabdominal aortic aneurysms

Efficacy and Safety of Endovascular Fenestrated and Branched Grafts Versus Open Surgery in Thoracoabdominal Aortic Aneurysm Repair: An Updated Systematic Review, Meta-analysis, and Meta-regression

OBJECTIVE

To provide an updated systematic review and meta-analysis with meta-regression of efficacy and safety of fenestrated/branched endovascular repair of thoracoabdominal aortic aneurysms (TAAAs) compared with open repair.

BACKGROUND

Endovascular repair of TAAAs may be a promising alternative to open surgery by reducing invasiveness and expanding the eligible population, but evidence remains limited.

METHODS

We applied "Prepared Items for Systematic Reviews and Meta-analysis" guidelines to retrieve, quantitatively pool, and critically evaluate the efficacy and safety (including 30-day mortality, reintervention, spinal cord injury [SCI], and renal injury) of both approaches. Original studies were retrieved from PubMed, Embase, and Cochrane Library until April 20, 2022, excluding papers reporting <10 patients. Pooled proportions and means were determined using a random-effect model. Heterogeneity between studies was evaluated with I2 statistics.

RESULTS

Sixty-four studies met the predefined inclusion criteria. Endovascular cohort patients were older and had higher rates of comorbidities. Endovascular repair was associated with similar proportions of mortality (0.07, 95% confidence intervals [CI]: 0.06-0.08) compared with open repair (0.09, 95% CI: 0.08-0.12; P = 0.22), higher proportions of reintervention (0.19, 95% CI: 0.13-0.26 vs 0.06, 95% CI: 0.04-0.10; P < 0.01), similar proportions of transient SCI (0.07, 95% CI: 0.05-0.09 vs 0.06, 95% CI: 0.05-0.08; P = 0.28), lower proportions of permanent SCI (0.04, 95% CI: 0.03-0.05 vs 0.06, 95% CI: 0.05-0.07; P < 0.01), and renal injury (0.08, 95% CI: 0.06-0.10 vs 0.13, 95% CI: 0.09-0.17; P = 0.02). Results were affected by high heterogeneity and potential publication bias.

CONCLUSIONS

Despite these limitations and the lack of randomized trials, this meta-analysis suggests that endovascular TAAA repair could be a safer alternative to the open approach.

Covering the intercostal artery branching of the Adamkiewicz artery during endovascular aortic repair increases the risk of spinal cord ischemia

Objectives

This study aimed to determine the relationship between covering the intercostal artery branching of the Adamkiewicz artery (ICA-AKA) and spinal cord ischemia (SCI) during thoracic endovascular aortic repair (TEVAR).

Methods

Patients who underwent TEVAR from 2008 to 2022 were enrolled. Stent grafts covered the ICA-AKA in 108 patients (covered AKA group) and stent grafts didn't cover the ICA-AKA in 114 patients (uncovered AKA group). The characteristics of 58 patients from each group were matched based on propensity scores.

Results

No significant differences in SCI rates were detected between the covered AKA (10%; 11/108) and uncovered AKA (3.5%; 4/114) groups (P = .061). Shaggy aorta (odds ratio [OR], 5.16; 95% confidence interval [CI], 1.74-15.3, P = .003), iliac artery access (OR, 6.81; 95% CI, 2.22-20.9, P = .001), and procedural time (OR, 1.01; 95% CI, 1.00-1.02, P = .003) were risk factors for SCI in the entire cohort. Although covering the ICA-AKA (OR, 2.60; 95% CI, 0.86-7.88, P = .058) was not a significant risk factor, shaggy aorta (OR, 8.15; 95% CI, 2.07-32.1, P = .003), iliac artery access (OR, 9.09; 95% CI, 2.22-37.2, P = .002), and procedural time (OR, 1.01; 95% CI, 1.01-1.02, P = .008) were risk factors for SCI in the covered AKA group. No significant risk factors were detected in the uncovered AKA group.

Conclusions

Covering the ICA-AKA was not an independent risk for SCI in TEVAR. However, covering the ICA-AKA was indirectly associated with the risk of SCI in patients with shaggy aorta, iliac access, and procedural time.

A review of current status of cell-based therapies for aortic aneurysms

An aortic aneurysm (AA) is defined as focal aortic dilation that occurs mainly with older age and with chronic inflammation associated with atherosclerosis. The aneurysmal wall is a complex inflammatory environment characterized by endothelial dysfunction, macrophage activation, vascular smooth muscle cell (VSMC) apoptosis, and the production of proinflammatory molecules and matrix metalloproteases (MMPs) secreted by infiltrated inflammatory cells such as macrophages, T and B cells, dendritic cells, neutrophils, mast cells, and natural killer cells. To date, a considerable number of studies have been conducted on stem cell research, and growing evidence indicates that inflammation and tissue repair can be controlled through the functions of stem/progenitor cells. This review summarizes current cell-based therapies for AA, involving mesenchymal stem cells, VSMCs, multilineage-differentiating stress-enduring cells, and anti-inflammatory M2 macrophages. These cells produce beneficial outcomes in AA treatment by modulating the inflammatory environment, including decreasing the activity of proinflammatory molecules and MMPs, increasing anti-inflammatory molecules, modulating VSMC phenotypes, and preserving elastin. This article also describes detailed studies on pathophysiological mechanisms and the current progress of clinical trials.

Surgical Approaches to Single-Stage Extended Aortic Repair from the Ascending to the Distal Descending Aorta

Single-stage extended replacement from the ascending to the distal descending aorta or beyond is a formidable operation that should be preserved for those who have no other option or those who are physically fit, and should be performed in the experienced centers. Hybrid operations combining open surgical repair with thoracic endovascular aortic repair through a median sternotomy incision are preferable because these operations are less invasive than the extended open aortic repair and the risk of spinal cord ischemia is lower compared with the frozen elephant trunk operation. However, these operations are associated with the inherent demerits of endovascular aneurysm exclusion. When the underlying aortic pathology necessitates extended open aortic repair in a single stage, approaches such as the anterolateral partial sternotomy, straight incision with rib cross, and extended thoracotomy with sternal transection may be useful to provide sufficient exposure for both aortic reconstruction and organ protection, with less surgical stress to the patients.

A Systematic Review of Spinal Cord Ischemia Prevention and Management After Open and Endovascular Aortic Repair

OBJECTIVE

Spinal cord ischemia (SCI) is one of the most devastating complications after descending thoracic aortic (DTA) and thoracoabdominal aortic (TAA) repairs. Patients who develop SCI have a poor prognosis with mortality rates reaching 75% within the first year after surgery. Many factors have been shown to increase the risk of this complication, including extent of TAA repair, length of aortic and collateral network coverage, embolization, and reduced spinal cord perfusion pressure. As a result, a variety of treatment strategies have evolved. We aimed to provide an up-to-date review of SCI rates with associated treatment algorithms from open and endovascular DTA and TAA repairs.

METHODS

Using PRISMA guidelines, a literature review with the Medical Subject Headings (MeSH) terms "spinal cord ischemia; spinal cord ischemia prevention and mitigation strategies; spinal cord ischemia rates; spinal cord infarction" was performed in the Cochrane and PubMed databases to seek all peer-reviewed studies of DTA and TAA repairs with SCI complications, limited to 2012-2021 and the English language. MeSH subheadings including diagnosis, complications, physiopathology, surgery, mortality, and therapy were used to further restrict the articles. Studies were excluded if they were not in humans, not pertaining to SCI in DTA/TAA operative repairs, and if the study primarily discussed neuromonitoring techniques. Additionally, studies with <40 patients or limited information regarding SCI protection strategies were excluded. Each study was individually reviewed by two researchers to assess for type and extent of aortic pathology, operative technique, SCI protection or mitigation strategies, rates of overall and permanent SCI symptoms, associations with SCI on multivariate analysis, and mortality.

RESULTS

Of 450 studies returned by the MeSH search strategy, 41 met inclusion criteria and were included in the final analysis. For endovascular DTA repair patients, overall SCI rates ranged from 0-10.6% with permanent SCI symptoms ranging from 0-5.1%. Endovascular and open TAA repairs had rates of overall SCI of 0-35%. Permanent SCI symptom rate was reported by only one open study at 1.1% while endovascular TAA repairs had between 2-20.5%.

CONCLUSION

This review provides an up-to-date review of current rates of SCI as well as prevention and mitigation strategies for DTA and TAA repairs. We find that a multimodal approach, including a bundled institutional protocol, staging of multiple repairs, preservation of collateral blood flow network, augmented spinal cord perfusion, selective cerebrospinal fluid drainage, and distal aortic perfusion in open TAA repairs, appears to be important in reducing the risk of SCI.

Endovascular repair for thoracoabdominal aortic aneurysms: current status and future challenges

Open surgical repair has been the gold standard for treatment of thoracoabdominal aortic aneurysms (TAAA). Currently, open surgical repair has been reserved mostly for young and fit patients with connective tissue disorders, using separate branch vessel reconstructions instead of 'island' patches, and distal perfusion instead of a 'clamp and go' technique. Endovascular repair has gained widespread acceptance because of its potential to significantly decrease morbidity and mortality. Several large aortic centers have developed dedicated clinical programs to advance techniques of fenestrated-branched endovascular aortic repair (FB-EVAR) using patient-specific and off-the-shelf devices, which offers a less-invasive alternative to open repair. Although FB-EVAR was initially considered an option for older and frail patients, many centers have expanded its indications to any patient with suitable anatomy and no evidence of connective tissue disorders, independent of their clinical risk. In this article, we review current techniques and outcomes of endovascular TAAA repair.

Clinical feasibility and safety of transoesophageal motor-evoked potential monitoring

OBJECTIVES

Canine experiments have shown that transoesophageal motor-evoked potential monitoring is feasible, safe and stable, with a quicker response to ischaemia and a better prognostic value than transcranial motor-evoked potentials. We aimed to elucidate whether or not these findings were clinically reproducible.

METHODS

A bipolar oesophageal electrode mounted on a large-diameter silicon tube and a train of 5 biphasic wave stimuli were used for transoesophageal stimulation. Results of 18 patients (median age 74.5 years, 13 males) were analysed.

RESULTS

There were no mortalities, spinal cord injuries or complications related with transoesophageal stimulation. Transcranial motor-evoked potential could not be monitored up to the end of surgery in 3 patients for unknown reasons, 2 of whom from the beginning. Transoesophageal motor-evoked potential became non-evocable after manipulation of a transoesophageal echo probe in 2 patients. Strenuous movement of the upper limbs during transoesophageal stimulation was observed in 3 patients. In 14 patients who successfully completed both monitoring methods up to the end of surgery (11 thoraco-abdominal and 3 descending aortic repair), the final results were judged as false positives in 6 by transcranial stimulation and in 1 by transoesophageal stimulation. The stimulation intensity was significantly lower and the upper limb amplitude was significantly higher by transoesophageal stimulation, while the lower limb amplitude was comparable.

CONCLUSIONS

Transoesophageal motor-evoked potential monitoring is clinically feasible and safe with a low false positive rate. A better electrode design is required to avoid its migration by transoesophageal echo manipulation. Further studies may be warranted.

CLINICAL REGISTRATION NUMBER

UMIN000022320.

Systematic review of contemporary outcomes of endovascular and open thoracoabdominal aortic aneurysm repair

OBJECTIVE

The purpose of the study was to provide a systematic review of the literature reporting the contemporary early outcomes after endovascular and open repair of thoracoabdominal aortic aneurysms (TAAAs).

METHODS

MEDLINE and Embase were searched for studies from January 2006 to March 2018 that reported either endovascular (using branched or fenestrated endografts) or open repair of TAAA in at least 10 patients. Outcomes of interest included perioperative mortality, spinal cord injury (SCI), renal failure requiring dialysis, and stroke. Pooled proportions were determined using a random-effects model.

RESULTS

The analysis included 71 studies, of which 24 and 47 reported outcomes after endovascular and open TAAA repair, respectively. Endovascular cohort patients were older and had higher rates of coronary artery disease, chronic obstructive pulmonary disease, and diabetes. Endovascular repair was associated with higher rates of SCI (13.5%; 95% confidence interval [CI], 10.5%-16.7%) compared with open repair (7.4%; 95% CI, 6.2%-8.7%; P < .01) but similar rates of permanent paralysis (5.2% [95% CI, 3.8%-6.7%] vs 4.4% [95% CI, 3.3%-5.6%]; P = .39), lower rates of postoperative dialysis (6.4% [95% CI, 3.2%-9.5%] vs 12.0% [95% CI, 8.2%-16.3%]; P = .03) but similar rates of being discharged on permanent dialysis (3.7% [95% CI, 2.0%-5.9%] vs 3.8% [95% CI, 2.9%-5.3%]; P = .93), a trend to lower stroke (2.7% [95% CI, 1.9%-3.6%] vs 3.9% [95% CI, 3.0%-4.9%]; P = .06), and similar perioperative mortality (7.4% [95% CI, 5.9%-9.1%] vs 8.9% [95% CI, 7.2%-10.9%]; P = .21).

CONCLUSIONS

This systematic review summarizes the contemporary literature results of endovascular and open TAAA repair. Endovascular repair studies included patients with more comorbidities and were associated with higher rates of SCI but similar rates of permanent paraplegia, whereas open repair studies had higher rates of postoperative dialysis but similar rates of being discharged on permanent dialysis. Perioperative mortality rates were similar. Universally adopted reporting standards for patient characteristics, outcomes, and the conduct of contemporary comparative studies will allow better assessment and comparisons of the risks associated with the two surgical treatment options for TAAA.

Transapical aortic perfusion using a deep hypothermic procedure during descending thoracic or thoracoabdominal aortic surgery

BACKGROUND

In descending thoracic aortic aneurysm (DTAA) or thoracoabdominal aortic aneurysm (TAAA) surgery, though proximal anastomosis using deep hypothermic circulatory arrest (DHCA) is often selected, there are issues surrounding brain and heart protection. In this study, the usefulness of concomitant upper body perfusion via transapical aortic cannulation during deep hypothermic surgery was examined.

METHODS

Between October 2014 and May 2019, 5 patients (Crawford extent II chronic dissection, N.=3; extent IV aneurysms, N.=1; DTAA, N.=1) underwent DTAA/TAAA repair under deep hypothermia using transapical aortic perfusion. A proximal anastomosis and artery of Adamkiewicz (AKA) reconstruction were performed under continuous perfusion of the upper and lower body at 20 °C.

RESULTS

The time from aortic cross-clamping to proximal anastomosis was 69±33 minutes, and it took 86±47 minutes to AKA reperfusion. There was no spinal cord ischemic injury or brain or heart complications. One patient required tracheostomy, and the average postoperative intubation time for the other patients was 57±52 hours. All patients were discharged, and the average postoperative hospital stay was 25.6±8.1 days.

CONCLUSIONS

Concomitant upper body perfusion by the transapical aortic approach contributes to avoidance of brain and heart complications and maintaining spinal cord circulation under deep hypothermic DTAA/TAAA surgery.