Surgical Decision Making in Uncomplicated Type B Aortic Dissection: A Survey of Australian/New Zealand and European Surgeons

Trends in the incidence, surgical management and outcomes of type B aortic dissections in Australia over the last decade

OBJECTIVES

This study aims to investigate the incidence and in-hospital outcomes of surgical repair for type B aortic dissection (TBAD) in Australia.

METHODS

Data were obtained from the Australasian Vascular Audit (AVA) and the Australian Institute of Health and Welfare (AIHW). The former is a total practice audit mandated for all members of the Australian and New Zealand Society for Vascular Surgery (ANZSVS) while the latter is an independent government agency which records all healthcare data in Australia. All cases of TBAD which underwent surgical intervention (endovascular or open repair) between 2010 and 2019 were identified using prospectively recorded data from the AVA (New Zealand data was excluded). The primary outcomes were temporal trends in procedures and hospital mortality; secondary outcomes were complications and risk factors for mortality. All admissions and procedures for, and hospital deaths from, TBAD in Australia were identified in AIHW datasets using the relevant diagnosis and procedure codes, with age-standardized rates calculated for the period 2000-01 to 2018-19.

RESULTS

A total of 567 cases of TBAD underwent vascular surgical intervention (AVA data, Australia). Of these, 96.3% were treated by endovascular repair. There was an increase in the annual procedure number from 45 in 2010 to 88 in 2019. In-hospital mortality was 4.8% for endovascular repair and 19% for open repair (p = 0.021). From 2000-01 to 2018-19, the age-standardized procedure rates for TBAD (Australia) doubled, the proportion of admitted patients undergoing a procedure rose from 28% to 43%, and in-hospital deaths fell by 25%.

CONCLUSION

There has been an increasing incidence of vascular surgical intervention for TBAD in Australia. The majority of patients received endovascular therapy while the mortality from surgically managed TBAD appears to be falling.

Novel insights into thoracic endografts technology for prevention of distal stent-graft induced new entry (dSINE) following endovascular repair of type B aortic dissections: from bench to bedside

INTRODUCTION

Endovascular treatment of type B aortic dissections (TBAD) has currently acquired a primary therapeutic role when anatomically feasible. The main issue with thoracic endovascular aortic repair (TEVAR) for aortic dissection is the actual nature of the aortic wall, which is structurally compromised and more fragile. Indeed, a wealth of data have shown that TEVAR for TBAD will lead, in a substantial proportion of cases, to a device-related adverse event named distal stent-graft induced new entry (dSINE).

AREAS COVERED

Currently available aortic stent-grafts have not been specifically devised for the treatment of aortic dissection. A novel dissection specific stent-graft (DSSG) was developed, which is a custom-made device based on the Zenith Alpha Thoracic platform (Cook Medical). The DSSG has several unique properties that, in principle, make its use optimal in TBAD patients.

EXPERT OPINION

TEVAR in the setting of aortic dissections remains technically challenging. The occurrence of dSINE represents a unique complication in this scenario and may lead to high rates of aortic-related adverse events and need for secondary interventions. The use of a novel custom-made DSSG in the setting of chronic TBAD has been proven to be safe, feasible and effective. However, even this approach may fail to completely prevent dSINE formation.

Hybrid surgery of vertebral artery transposition combined with scallop and fenestration technique for the repair of type B aortic dissection patient with isolated left vertebral artery: A case report

RATIONALE

Acute type B aortic dissection (ABAD) is a fatal cardiovascular disease with high morbidity and mortality. Isolated left vertebral artery (ILVA) is a rare aortic arch mutation originating from the aortic arch. The simultaneous occurrence of both increases the complexity and difficulty of thoracic endovascular aortic repair. However, there have been few reports on the recommendation of thoracic endovascular aortic repair treatment strategies for aortic dissection patients concomitant ILVA with insufficient landing zone. Here, we report a case of ABAD combined with ILVA treated with hybrid surgery of left vertebral artery transposition alliance with Scallop and in vivo fenestration endograft.

PATIENT CONCERNS

A 38-year-old middle-aged man was transferred to our vascular department with persistent pain in his lower abdomen for 8 hours.

DIAGNOSES

Preoperative computed tomography angiogram of the thoracic and abdominal aorta diagnosed with ABAD accompanied with ILVA.

INTERVENTIONS

Hybrid surgery of left vertebral artery transposition alliance with Scallop and in situ fenestration endograft for revascularization of ILVA, left subclavian artery, and left common carotid artery.

OUTCOMES

The hybridization operation was successfully completed. There were no complications of cerebral and spinal cord ischemia after operation. Computed tomography angiogram examination indicated no internal leakage existed in the stent and patency of the arch vessels and the transposed left vertebral artery follow-up 3 months after surgery.

LESSONS

This study gave us experience in the treatment of aortic dissection with left vertebral artery variation and suggested that left vertebral artery transposition combined with scallop and in vivo fenestration stent is safe and effective.

Acute Aortic Syndromes from Diagnosis to Treatment-A Comprehensive Review

This work aims to provide a comprehensive description of the characteristics of a group of acute aortic diseases that are all potentially life-threatening and are collectively referred to as acute aortic syndromes (AASs). There have been recent developments in the care and diagnostic plan for AAS. A substantial clinical index of suspicion is required to identify AASs before irreversible fatal consequences arise because of their indefinite symptoms and physical indicators. A methodical approach to the diagnosis of AAS is addressed. Timely and suitable therapy should be started immediately after diagnosis. Improving clinical outcomes requires centralising patients with AAS in high-volume centres with high-volume surgeons. Consequently, the management of these patients benefits from the increased use of aortic centres, multidisciplinary teams and an "aorta code". Each acute aortic entity requires a different patient treatment strategy; these are outlined below. Finally, numerous preventive strategies for AAS are discussed. The keys to good results are early diagnosis, understanding the natural history of these disorders and, where necessary, prompt surgical intervention. It is important to keep in mind that chest pain does not necessarily correspond with coronary heart disease and to be alert to the possible existence of aortic diseases because once antiplatelet drugs are administered, a blocked coagulation system can complicate aortic surgery and affect prognosis. The management of AAS in "aortic centres" improves long-term outcomes and decreases mortality rates.

Hemodynamic Implications of STABILISE Technique for Aortic Dissection Repair

BACKGROUND

The stent-assisted balloon-induced intimal disruption and relamination (STABILISE) technique for treatment of type B dissection has shown promising clinical results at mid-term. Computational modeling is a way of noninvasively obtaining hemodynamic effects, such as pressure and wall shear stress, leading to a better understanding of potential benefits. Particular areas of interest are (1) the effect of intimal disruption and re-lamination and (2) the effect of the bare metal stent in the visceral aortic segment.

METHODS

Single-center prospective case series. Data from 5 consecutive locally performed cases of STABILISE technique were analyzed. Included cases were type B aortic dissection with or without prior de-branching. The STABILISE procedure had to be performed without 30-day major complications. Preoperative and postoperative imaging data for each patient were transferred to the biomedical engineering team. Each case was reconstructed, meshed, and simulated with computational fluid dynamics using patient-specific data (heart rate, blood pressure, height, and weight). Hemodynamic parameters were then extracted from the simulations.

RESULTS

In all cases, computational analysis showed for postoperative patients: (1) a drop in pressure difference between lumina and (2) lower wall shear stress effects, compared to their preoperative status. These observations were most pronounced in the visceral aortic segment.

CONCLUSIONS

Computational modeling shows favourable changes in the flow dynamics of type B dissection treated using the STABILISE technique. This may suggest protective effects of this technique for long-term aortic healing and cicatrization.

Initial Thoracic Endovascular Aortic Repair vs Medical Therapy for Acute Uncomplicated Type B Aortic Dissection

Importance

Thoracic endovascular aortic repair (TEVAR) has increasingly been used for uncomplicated type B aortic dissection (uTBAD) despite limited supporting data.

Objective

To assess whether initial TEVAR following uTBAD is associated with reduced mortality or morbidity compared with medical therapy alone.

Design, Setting, and Participants

This cohort study included Centers for Medicare & Medicaid Services inpatient claims data for adults aged 65 years or older with index admissions for acute uTBAD from January 1, 2011, to December 31, 2018, with follow-up available through December 31, 2019.

Exposures

Initial TEVAR was defined as TEVAR within 30 days of admission for acute uTBAD.

Main Outcomes and Measures

Outcomes included all-cause mortality, cardiovascular hospitalizations, aorta-related and repeated aorta-related hospitalizations, and aortic interventions associated with initial TEVAR vs medical therapy. Propensity score inverse probability weighting was used.

Results

Of 7105 patients with eligible index admissions for acute uTBAD, 1140 (16.0%) underwent initial TEVAR (623 [54.6%] female; median age, 74 years [IQR, 68-80 years]) and 5965 (84.0%) did not undergo TEVAR (3344 [56.1%] female; median age, 76 years [IQR, 69-83 years]). Receipt of TEVAR was associated with region (vs South; Midwest: adjusted odds ratio [aOR], 0.66 [95% CI, 0.53-0.81]; P < .001; Northeast: aOR, 0.63 [95% CI, 0.50-0.79]; P < .001), Medicaid dual eligibility (aOR, 0.76; 95% CI, 0.63-0.91; P = .003), hypertension (aOR, 1.26; 95% CI, 1.03-1.54; P = .03), peripheral vascular disease (aOR, 1.24; 95% CI, 1.02-1.49; P = .03), and year of admission (2012, 2013, 2014, and 2015 were associated with greater odds of TEVAR compared with 2011). After inverse probability weighting, mortality was similar for the 2 strategies up to 5 years (hazard ratio [HR], 0.95; 95% CI, 0.85-1.06), as were aorta-related hospitalizations (HR, 1.12; 95% CI, 0.99-1.27), aortic interventions (HR, 1.01; 95% CI, 0.84-1.20), and cardiovascular hospitalizations (HR, 1.05; 95% CI, 0.93-1.20). In a sensitivity analysis that included deaths within the first 30 days, initial TEVAR was associated with lower mortality over a period of 1 year (adjusted HR [aHR], 0.86; 95% CI, 0.75-0.99; P = .03), 2 years (aHR, 0.85; 95% CI, 0.75-0.96; P = .008), and 5 years (aHR, 0.87; 95% CI, 0.80-0.96; P = .004).

Conclusions and Relevance

In this study, 16.0% of patients underwent initial TEVAR within 30 days of uTBAD, and receipt of initial TEVAR was associated with hypertension, peripheral vascular disease, region, Medicaid dual eligibility, and year of admission. Initial TEVAR was not associated with improved mortality or reduced hospitalizations or aortic interventions over a period of 5 years, but in a sensitivity analysis that included deaths within the first 30 days, initial TEVAR was associated with lower mortality. These findings, along with cost-effectiveness and quality of life, should be assessed in a prospective trial in the US population.

Cost analysis of thoracic endovascular aortic repair in type B aortic dissection: How much does quality cost?

BACKGROUND

Aortic dissection (AD) is a life-threatening medical emergency that affects an estimated 3-4 people per 100,000 annually, with 40% of cases classified as type B AD (TBAD). TBAD can be further classified as being complicated (co-TBAD) or uncomplicated (un-TBAD) based on the presence or absence of certain features such as malperfusion and rupture. TBAD can be managed conservatively with optimal medical therapy (OMT), or invasively with open surgical repair (OSR) or thoracic endovascular aortic repair (TEVAR), depending on several factors such as type of TBAD and its clinical acuity. The cost-effectiveness, or cost-benefit profile, of these strategies must be given equal consideration. However, TBAD studies featuring cost analyses are limited within the literature. This narrative review aims to address the gap in the literature on cost-effectiveness of TBAD treatments by providing an overview of cost analyses comparing OMT with TEVAR in un-TBAD and TEVAR with OSR in co-TBAD. Another aim is to provide a market analysis of the commercially available TEVAR devices.

METHODS

A comprehensive literature search was performed using several search engines including PubMed, Ovid, Google Scholar, Scopus, and Embase to identify and extract relevant studies.

RESULTS

Several TEVAR devices are available commercially on the global market costing $12,000-19,495. Nevertheless, the Terumo Aortic RELAY® stent graft seems to be the most cost-effective, yielding highly favourable clinical outcomes. Despite the higher initial cost of TEVAR, evidence in the literature strongly suggest that it is superior to OMT for un-TBAD on the long-term. In addition, TEVAR is well established in the literature as being gold-standard repair technique for co-TBAD, replacing OSR by offering a more optimal cost-benefit profile through lower costs and improved results.

CONCLUSIONS

The introduction of TEVAR has revolutionized the field of aortovascular surgery by offering a highly efficacious and long-term cost-effective treatment for TBAD.

Acute or Subacute, the Optimal Timing for Uncomplicated Type B Aortic Dissection: A Systematic Review and Meta-Analysis

Objective

To evaluate the optimal timing (acute or subacute) of thoracic endovascular aortic repair (TEVAR) for uncomplicated B aortic dissection (uTBAD) through a systematic review and meta-analysis.

Method

A comprehensive literature search was undertaken across three major databases (EMBASE/Medline, PubMed, and Cochrane Library) and was assessed until November 2021 to identify studies reporting the outcomes of TEVAR utilized to treat patients with uTBAD. The continuous variables were compared between the two groups using t-test and the categorical variables were compared using the χ2-test. A meta-analysis was used to produce pooled odds ratios for early and follow-up outcomes. The random effects models were applied. A statistical analysis was performed using R software v.4.1.

Result

A comprehensive literature search found 490 citations published within the predetermined time span of the analysis. Three studies including 1,193 patients (acute group 718, subacute group 475) were finally included for downstream meta-analysis. An acute uTBAD group presented with higher rates both in 30-day complications (20.5 vs. 13.7%; p = 0.014) and mortality (4.6 vs. 1.3%; p = 0.004) than subacute group. The respiratory complications were significantly higher in the acute group than in the subacute group (10.8 vs. 5.0%; p = 0.015). The procedure success rate (90.8 vs. 93.6%; p = 0.329), the follow-up mortality (7.7 vs. 7.6%; p = 1) and dissection-related late mortality (3.9 vs. 5.3%; p = 0.603) showed no significant difference.

Conclusion

Our meta-analysis suggested that despite significantly higher 30-day complications and 30-day mortality in the acute uTBAD group, there was no significant difference in the follow-up mortality between the two groups.

Systematic Review Registration

PROSPERO, identifier: CRD42021247609.

Criteria for endovascular intervention in type B aortic dissection

BACKGROUND

The use of thoracic endovascular aortic repair (TEVAR) for the management of uncomplicated type B aortic dissection (un-TBAD) remains controversial. There is a lack of consensus over whether pre-emptive TEVAR should be carried out in patients with un-TBAD at risk of progression to complicated TBAD. We present a review of current evidence and seek to suggest criteria where endovascular intervention in un-TBAD may prove beneficial relative to pharmacotherapy alone.

METHODS AND MATERIALS

PubMed and Cochrane databases were searched using terms including: type B aortic dissection, risk factors, medical therapy, TEVAR, false lumen (FL) expansion, and mortality. Papers were selected based on title and abstract.

RESULTS

Optimal medical therapy remains the mainstay treatment for patients with un-TBAD, however, patients with un-TBAD present with varying degrees of disease progression risk. Factors such as age, aortic morphology, history of connective tissue disorders, FL thrombosis, and aortic branch involvement may potentiate progression from un-TBAD to complicated TBAD. Short- and long-term outcomes associated with TEVAR for TBAD remain promising.

CONCLUSION

Pre-emptive TEVAR may be beneficial in patients with un-TBAD presenting with the above factors, however, further prospective research into the optimal timing for TEVAR in un-TBAD is required.

Proximal False Lumen Thrombosis is Associated with Low False Lumen Pressure and Fewer Complications in Type B Aortic Dissection

BACKGROUND

Improved risk stratification is a key priority for type B aortic dissection (TBAD). Partial false lumen thrombus morphology is an emerging predictor of complications however, partial thrombosis is poorly defined and its evaluation in clinical studies is inconsistent.

PURPOSE

This work aims to characterise hemodynamic pressure in TBAD and determine how pressure relates to false lumen thrombus morphology and clinical events.

METHODS

Retrospective admission computed tomography angiography of 69 patients with acute TBAD was used to construct three-dimensional computational models for simulation of cyclical blood flow and calculation of pressure. Patients were categorised based on false lumen thrombus morphology: minimal; proximal; distal; or extensive thrombosis. Linear regression analysis compared the luminal pressure difference between the true and false lumen for each morphology group. The impact of morphology classification on acute complications within 14 days was studied using logistic regression adjusted for clinical parameters. A survival analysis for adverse aortic events at one-year was also performed using Cox regression.

RESULTS

44 patients experienced acute complications and 45 had an adverse aortic event at one-year. Mean (±standard deviation) age was 62.6 (±12.6) years and 75.4% were male. Compared to patients with minimal thrombosis, those with proximal thrombosis had reduced false lumen pressure by 10.1mmHg (95% CI 4.3-15.9mmHg, p=.001). Individuals that did not experience an acute complication had reduced relative false lumen pressure (-6.35mmHg vs -0.62mmHg, p=.03). Proximal thrombosis was associated with fewer acute complications (OR 0.17, 95% CI 0.04-0.60 p=.01) and one-year adverse aortic events (HR 0.36, 95% CI 0.16-0.80, p=.01).

CONCLUSIONS

Proximal false lumen thrombosis is a marker of reduced false lumen pressure. This may explain how proximal false lumen thrombosis appears protective of acute complications (refractory hypertension or pain, aortic rupture, visceral or limb malperfusion and acute expansion) and adverse aortic events within the first year.