Feasibility of a proposed randomized trial in patients with uncomplicated descending thoracic aortic dissection: Results of worldwide survey

Navigating clinical appropriateness: A review of management strategies for type B aortic dissection

Aortic dissection is a catastrophic, life-threatening event. Its management depends on the anatomic location of the intimal tear (type A v B) and the clinical presentation in type B aortic dissection. In this article, the current evidence supporting clinical practice, gaps in knowledge, and the need for more rigorous research and higher-quality studies are reviewed.

Editor's Choice - Trends in Management and Outcomes of Type B Aortic Dissection: A Report From the International Registry of Aortic Dissection

OBJECTIVE

To describe the trends in management and outcomes of patients with acute type B aortic dissection in the International Registry of Acute Aortic Dissection.

METHODS

From 1996 - 2022, 3 908 patients were divided into similar sized quartiles (T1, T2, T3, and T4). In hospital outcomes were analysed for each quartile. Survival rates following admission were compared using Kaplan-Meier analyses with Mantel-Cox Log rank tests.

RESULTS

Endovascular treatment increased from 19.1% in T1 to 37.2% in T4 (ptrend < .001). Correspondingly, medical therapy decreased from 65.7% in T1 to 54.0% in T4 (ptrend < .001), and open surgery from 14.8% in T1 to 7.0% in T4 (ptrend < .001). In hospital mortality decreased in the overall cohort from 10.7% in T1 to 6.1% in T4 (ptrend < .001), as well as in medically, endovascularly and surgically treated patients (ptrend = .017, .033, and .011, respectively). Overall post-admission survival at three years increased (T1: 74.8% vs. T4: 77.3%; p = .006).

CONCLUSION

Considerable changes in the management of acute type B aortic dissection were observed over time, with a significant increase in the use of endovascular treatment and a corresponding reduction in open surgery and medical management. These changes were associated with a decreased overall in hospital and three year post-admission mortality rate among quartiles.

Scandinavian trial of uncomplicated aortic dissection therapy: study protocol for a randomized controlled trial

BACKGROUND

Contemporary management of uncomplicated type B aortic dissections (uTBAD) is based on the acuity and various morphological features. Medical therapy is mandatory, while the risks of early thoracic endovascular aortic repair (TEVAR) are balanced against the potential for rupture, complex surgery, and death. Improved aortic morphology following TEVAR is documented, but evidence for improved overall survival is lacking. The costs and impact on quality of life are also needed.

METHODS

The trial is a randomized, open-label, superiority clinical trial with parallel assignment of subjects at 23 clinical sites in Denmark, Norway, Sweden, Finland, and Iceland. Eligibility includes patients aged ≥ 18 with uTBAD of < 4 weeks duration. Recruited subjects will be randomized to either standard medical therapy (SMT) or SMT + TEVAR, where TEVAR must be performed between 2-12 weeks from the onset of symptoms.

DISCUSSION

This trial will evaluate the primary question of whether early TEVAR improves survival at 5 years among uTBAD patients. Moreover, the costs and the impact on quality of life should provide sorely needed data on other factors that play a role in treatment strategy decisions. The common Nordic healthcare model, with inclusion of all aortic centers, provides a favorable setting for carrying out this trial, while the robust healthcare registries ensure data validity.

TRIAL REGISTRATION

ClinicalTrials.gov NCT05215587. Registered on January 31, 2022.

Endovascular treatment of complicated versus uncomplicated acute type B aortic dissection

OBJECTIVE

The study objective was to analyze the outcomes of thoracic endovascular aortic repair performed for complicated and uncomplicated acute type B aortic dissections.

METHODS

Patients from WL Gore's Global Registry for Endovascular Aortic Treatment who underwent thoracic endovascular aortic repair for acute type B aortic dissections were included, and data were retrospectively analyzed.

RESULTS

Of 5014 patients enrolled in the Global Registry for Endovascular Aortic Treatment, 172 underwent thoracic endovascular aortic repair for acute type B aortic dissections. Of these repairs, 102 were for complicated acute type B aortic dissections and 70 were for uncomplicated acute type B aortic dissections. There were 46 (45.1%) procedures related to aortic branch vessels versus 15 (21.4%) in complicated type B aortic dissections and uncomplicated type B aortic dissections (P = .002). The mean length of stay was 14.3 ± 10.6 days (median, 11; range, 2-75) versus 9.8 ± 7.9 days (median, 8; range, 0-42) in those with complicated type B aortic dissections versus those with uncomplicated acute type B aortic dissections (P < .001). Thirty-day mortality was not different between groups (complicated type B aortic dissections 2.9% vs uncomplicated acute type B aortic dissections 1.4%, P = .647), as well as aortic complications (8.8% vs 5.7%, P = .449). Aortic event-free survival was 62.9% ± 37.1% versus 70.6% ± 29.3% at 3 years (P = .696).

CONCLUSIONS

In the Global Registry for Endovascular Aortic Treatment, thoracic endovascular aortic repair results for complicated type B aortic dissections versus uncomplicated acute type B aortic dissections showed that 30-day mortality and perioperative complications were equally low for both. The midterm outcome was positive. These data confirm that thoracic endovascular aortic repair as the first-line strategy for treating complicated type B dissections is associated with a low risk of complications. Further studies with longer follow-up are necessary to define the role of thoracic endovascular aortic repair in uncomplicated acute type B dissections compared with medical therapy. However, in the absence of level A evidence from randomized trials, results of the uncomplicated acute type B aortic dissection patient cohort treated with thoracic endovascular aortic repair from registries are important to understand the related risk and benefit.

Registry of Aortic Diseases to Model Adverse Events and Progression (ROADMAP) in Uncomplicated Type B Aortic Dissection: Study Design and Rationale

Purpose

To describe the design and methodological approach of a multicenter, retrospective study to externally validate a clinical and imaging-based model for predicting the risk of late adverse events in patients with initially uncomplicated type B aortic dissection (uTBAD).

Materials and Methods

The Registry of Aortic Diseases to Model Adverse Events and Progression (ROADMAP) is a collaboration between 10 academic aortic centers in North America and Europe. Two centers have previously developed and internally validated a recently developed risk prediction model. Clinical and imaging data from eight ROADMAP centers will be used for external validation. Patients with uTBAD who survived the initial hospitalization between January 1, 2001, and December 31, 2013, with follow-up until 2020, will be retrospectively identified. Clinical and imaging data from the index hospitalization and all follow-up encounters will be collected at each center and transferred to the coordinating center for analysis. Baseline and follow-up CT scans will be evaluated by cardiovascular imaging experts using a standardized technique.

Results

The primary end point is the occurrence of late adverse events, defined as aneurysm formation (≥6 cm), rapid expansion of the aorta (≥1 cm/y), fatal or nonfatal aortic rupture, new refractory pain, uncontrollable hypertension, and organ or limb malperfusion. The previously derived multivariable model will be externally validated by using Cox proportional hazards regression modeling.

Conclusion

This study will show whether a recent clinical and imaging-based risk prediction model for patients with uTBAD can be generalized to a larger population, which is an important step toward individualized risk stratification and therapy.Keywords: CT Angiography, Vascular, Aorta, Dissection, Outcomes Analysis, Aortic Dissection, MRI, TEVAR© RSNA, 2022See also the commentary by Rajiah in this issue.

Epidemiology and management of aortic disease: aortic aneurysms and acute aortic syndromes

The aorta is the 'greatest artery', through which oxygenated blood is delivered from the left ventricle to end organs with each cardiac cycle (200 million litres of blood transported in an average lifetime). The aorta can be affected by a wide spectrum of acute factors (such as cocaine use, weight lifting and trauma) and chronic acquired and/or genetic conditions (such as systemic arterial hypertension and phaeochromocytoma), which variously lead to increased aortic wall stress. The medial layer of the aorta can also be subject to abnormalities (such as Marfan syndrome, bicuspid aortic valve, inflammatory vasculitis, atherosclerosis and infections). Despite important advances in diagnostic and therapeutic interventions, data derived from registries and population-based studies highlight that the burden of aortic diseases remains high. Therefore, specific resources need to be allocated to design and implement preventive strategies (healthy lifestyles, modifications to cardiovascular risk factors, and educational and screening programmes) at individual and community levels. In this Review, we discuss the epidemiology, management and outcomes of the most common aortic diseases, namely, aortic aneurysms and acute aortic syndromes.

Management of Uncomplicated Type B Aortic Dissection

Acute aortic dissection has an incidence of approximately half that of symptomatic abdominal and thoracic aneurysm of the aorta and more than twice the mortality of population-based controls. While urgent undelayed open surgery is the strategy of choice in proximal dissection, medical management has been the mainstay of treatment for uncomplicated distal or type B aortic dissection, but endovascular intervention is now considered a potential treatment option for all type B dissection due to its success in complicated cases. Endovascular repair can be technically demanding in aortic dissection, and timing of the repair can have a significant influence on anatomical and clinical outcome. Observational reports of feasibility and reasonable safety are flanked by only two randomised trials; the Acute Dissection Stent Grafting or Best Medical Treatment (ADSORB) trial demonstrated improved remodelling in acute dissection and the INvestigation of STEnt grafts in patients with type B Aortic Dissections (INSTEAD) trial showed better long-term survival in patients treated endovascularly in the subacute phase. Meta-analyses and other large clinical studies have demonstrated mixed results. Due to some risks associated endovascular repair and the requirement of specialist aortic care (which is not always available), a pragmatic approach for current management could involve high intensity serial imaging in the acute phase of a type B aortic dissection, thereby identifying complicated cases for early intervention and selection of patients at high risk of disease progression for deferred endovascular management in the subacute phase within 90 days.

In situ diode laser fenestration of aortic arch stent grafts during thoracic endovascular aortic repair of Stanford type A aortic dissection

AIMS

The aim of the study was to evaluate the feasibility, safety, and effectiveness of in situ diode laser fenestration of thoracic endovascular aortic repair (TEVAR) stent grafts to treat Stanford type A aortic dissection.

METHODS AND RESULTS

Fifty-eight patients with acute or subacute Stanford type A aortic dissection treated with in situ diode laser fenestration during TEVAR under cerebral circulation protection with an extracorporeal bypass were reviewed retrospectively. Routine postoperative outcomes were recorded and assessed. Computed tomography angiography (CTA) was performed during the follow-up after 3, 6 and 12 months. Procedural success was achieved in 53 patients (91.4%). The average procedure time was 162±36 minutes. One patient died of pericardial tamponade during intervention, and one died of severe pneumonia after the intervention. Except for two minor strokes, no more fenestration-related complications occurred at 30 days and 12 months after the intervention. CTA imaging demonstrated 100% primary patency for the left subclavian artery and carotid arteries with favourable aortic remodelling after TEVAR during the follow-up. Two patients had a type Ia endoleak and one other a type II endoleak.

CONCLUSIONS

In situ diode laser fenestration during TEVAR for type A aortic dissection was found to be feasible, safe, and effective, and may be beneficial as a less invasive approach.

Four-dimensional flow cardiovascular magnetic resonance in aortic dissection: Assessment in an ex vivo model and preliminary clinical experience

OBJECTIVE

Four-dimensional flow cardiovascular magnetic resonance may improve assessment of hemodynamics in patients with aortic dissection. The purpose of this study was to evaluate the feasibility and accuracy of 4-dimensional flow cardiovascular magnetic resonance assessment of true and false lumens flow.

METHODS

Thirteen ex vivo porcine aortic dissection models were mounted to a flow loop. Four-dimensional flow cardiovascular magnetic resonance and 2-dimensional phase-contrast cardiovascular magnetic resonance measurements were performed, assessed for intraobserver and interobserver variability, and compared with a reference standard of sonotransducer flow volume measurements. Intraobserver and interobserver variability of 4-dimensional flow cardiovascular magnetic resonance were also assessed in 14 patients with aortic dissection and compared with 2-dimensional phase-contrast cardiovascular magnetic resonance.

RESULTS

In the ex vivo model, the intraobserver and interobserver measurements had Lin's correlation coefficients of 0.98 and 0.96 and mean differences of 0.17 (±3.65) mL/beat and -0.59 (±5.33) mL/beat, respectively; 4-dimensional and sonotransducer measurements had a Lin's concordance correlation coefficient of 0.95 with a mean difference of 0.35 (±4.92) mL/beat, respectively. In patients with aortic dissection, the intraobserver and interobserver measurements had Lin's concordance correlation coefficients of 0.98 and 0.97 and mean differences of -0.95 (±8.24) mL/beat and 0.62 (±10.05) mL/beat, respectively; 4-dimensional and 2-dimensional flow had a Lin's concordance correlation coefficient of 0.91 with a mean difference of -9.27 (±17.79) mL/beat because of consistently higher flow measured with 4-dimensional flow cardiovascular magnetic resonance in the ascending aorta.

CONCLUSIONS

Four-dimensional flow cardiovascular magnetic resonance is feasible in patients with aortic dissection and can reliably assess flow in the true and false lumens of the aorta. This promotes potential future work on functional assessment of aortic dissection hemodynamics.