Chronic descending aortic dissections

Long-term outcomes of thoracic endovascular aortic repair for chronic Stanford type B aortic dissection

OBJECTIVES

The aim of this study was to report the long-term outcomes of proximal thoracic endovascular aortic repair (TEVAR) for chronic Stanford type B aortic dissection (cTBAD).

METHODS

We retrospectively analyzed the clinical data of 48 cases of patients with cTBAD who underwent proximal TEVAR in Zhongshan Hospital Fudan University from January 2010 to September 2013. The preoperative and postoperative imaging examinations, overall survival rate, aortic-related survival rate, and freedom from reintervention rate data were collected to evaluate aortic remodeling and clinical outcomes. The enrolled patients received follow-up at 1, 3, 6, and 12 months following treatment and annually thereafter.

RESULTS

A total of 48 patients (mean age, 58.3 ± 10.6 years; men:women, 40:8) were included, of which 38 cases (79.2%) were uncomplicated dissection and 10 cases (20.8%) were complicated. The mean follow-up time was 48.7 ± 40 months (1-120 months). The mean time interval from the initial procedure to reintervention was 50.6 ± 32.7 months (11-98 months). The following changes were observed at preoperative versus last follow-up timepoints. Descending aortic level: true lumen, 19.2 ± 7.01 mm vs. 36.9 ± 9.53 mm (p < 0.001); false lumen, 30.47 ± 15.89 mm vs. 19.16 ± 15.33 mm (p < 0.001); maximum diameter, 49.67 ± 13.96 mm vs. 56.66 ± 14.95 mm (p = 0.018). Diaphragm level: true lumen, 16.24 ± 5.41 mm vs. 24.41 ± 8.04 mm (p < 0.001); false lumen, 12.37 ± 11.49 mm vs. 14.92 ± 12.25 mm (p = 0.196); and maximum diameter, 34 ± 7.81 mm vs. 38.04 ± 7.7 mm (p < 0.001). The freedom from reintervention rate was 81% in 5 years and 50.6% in 10 years. The overall 10-years survival rate was 83% (6 of 48), and the aortic-related survival rate was 92.3% (3 of 48).

CONCLUSIONS

TEVAR is a safe and effective proximal repair intervention for cTBAD that can reliably induce the positive remodeling of the descending aorta.

Thoracic endovascular repair of chronic type B aortic dissection: a systematic review

BACKGROUND

At present, the optimal management strategy for chronic type B aortic dissection (CTBAD) remains unknown, as equipoise remains regarding medical management versus endovascular treatment versus open surgery. However, the results over recent years of thoracic endovascular aortic repair (TEVAR) in CTBAD appear promising. The aim of this systematic review was to provide a comprehensive analysis of the available data reporting outcomes and survival rates for TEVAR in CTBAD.

METHODS

Electronic searches of six databases were performed from inception to April 2021. All studies reporting outcomes, specifically 30-day mortality rates, for endovascular repair of CTBAD were identified. Relevant data were extracted, and a random-effects meta-analysis of proportions or means was performed to aggregate the data. Survival data were pooled using data derived from original Kaplan-Meier curves, which allows reconstruction of individual patient data.

RESULTS

Forty-eight studies with 2,641 patients were identified. Early (<30 days) all-cause and aortic-related mortality rates were low at 1.6% and 0.5%, respectively. Incidence of retrograde type A dissection in the post-operative period was only 1.4%. There were also low rates of cerebrovascular accidents and spinal cord injury (1.1% and 0.9%, respectively). Late follow-up all-cause mortality was 8.0%, however, late aortic-related mortality was only 2.4%. Reintervention rates were 10.1% for endovascular and 6.7% for surgical reintervention. Pooled rates of overall survival at 1-, 3-, 5- and 10-year were 91.5%, 84.7%, 77.7% and 56.3%, respectively.

CONCLUSIONS

The significant heterogeneity in the available evidence and absence of consensus reporting standards are important considerations and concern when interpreting the data. Evaluation of the evidence suggests that TEVAR for CTBAD is a safe procedure with low rates of complications. However, the optimal treatment strategy for CTBAD remains debatable and requires further research. Evidence from high-quality registries and clinical trials are required to address these challenges.

An extensive chronic aortic dissection presenting with acute embolic stroke

Herein, we present a rare case of extensive chronic aortic dissection with extension to bilateral subclavian arteries, bilateral common carotid arteries, right internal carotid artery, bilateral proximal external iliac arteries and simultaneous presentation of acute embolic stroke and seizure. The rarity of this case presentation and the presence of neurological features necessitated a high index of clinical suspicion to reach the definitive diagnosis. This study also demonstrates a unique situation requiring correlation between chronic aortic dissection and multi-organ system dysfunction from chronic ischemia.

Multi-modality image-based computational analysis of haemodynamics in aortic dissection

Aortic dissection is a disease whereby an injury in the wall of the aorta leads to the creation of a true lumen and a false lumen separated by an intimal flap which may contain multiple communicating tears between the lumina. It has a high associated morbidity and mortality, but at present, the timing of surgical intervention for stable type B dissections remains an area of debate. Detailed knowledge of haemodynamics may yield greater insight into the long-term outcomes for dissection patients by providing a greater understanding of pressures, wall shear stress and velocities in and around the dissection. In this paper, we aim to gather further insight into the complex haemodynamics in aortic dissection using medical imaging and computational fluid dynamics modelling. Towards this end, several computer models of the aorta of a patient presenting with an acute Stanford type B dissection were created whereby morphometric parameters related to the dissection septum were altered, such as removal of the septum, and the variation of the number of connecting tears between the lumina. Patient-specific flow data acquired using 2D PC-MRI in the ascending aorta were used to set the inflow boundary condition. Coupled zero-dimensional (Windkessel) models representing the distal vasculature were used to define the outlet boundary conditions and tuned to match 2D PC-MRI flow data acquired in the descending aorta. Haemodynamics in the dissected aorta were compared to those in an equivalent ‘healthy aorta’, created by virtually removing the intimal flap (septum). Local regions of increased velocity, pressure, wall shear stress and alterations in flow distribution were noted, particularly in the narrow true lumen and around the primary entry tear. The computed flow patterns compared favourably with those obtained using 4D PC-MRI. A lumped-parameter heart model was subsequently used to show that in this case there was an estimated 14 % increase in left ventricular stroke work with the onset of dissection. Finally, the effect of secondary connecting tears (i.e. those excluding the primary entry and exit tears) was also studied, revealing significant haemodynamic changes when no secondary tears are included in the model, particularly in the true lumen where increases in flow over \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$+200\,\%$$\end{document}+200% and drops in peak pressure of 18 % were observed.