A systematic review of mid-term outcomes of thoracic endovascular repair (TEVAR) of chronic type B aortic dissection

Endovascular versus conventional medical treatment for uncomplicated chronic type B aortic dissection

BACKGROUND

Aortic dissection is a potentially life-threatening condition that occurs when a tear forms in the inner lining of the aorta. It has traditionally been treated by blood pressure control (medical treatment) or open surgery, both with high mortality rates. More recently stent-graft repair has been suggested as an alternative.

OBJECTIVES

To identify the best management for uncomplicated (without rupture of the organs or malperfusion of the extremities) subacute or chronic type B aortic dissection.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched their Specialised Register (last searched May 2012) and CENTRAL (2012, Issue 4). Clinical trials databases were searched for ongoing or unpublished studies.

SELECTION CRITERIA

All randomised controlled trials designed to compare the outcome of uncomplicated (without rupture of the organs or malperfusion of the extremities) chronic (occurring more than two weeks previously) type B aortic dissection when treated by stenting adjunctive to best medical treatment versus best medical treatment alone were included.

DATA COLLECTION AND ANALYSIS

Data on all cause and aorta-related mortality at two years was collected and analysed. In addition, secondary outcome measures were analysed, including morbidity, complications (additional endovascular or open surgery for rupture, expansion or malperfusion) and quality of life.

MAIN RESULTS

A single trial was identified that fulfilled the inclusion criteria (INSTEAD trial). The two-year all cause survival was not statistically significantly different between study groups (95.6% ± 2.5% in the optimised medical therapy (OMT) group and 88.9% ± 3.7% in the thoracic endovascular aneurysm repair (TEVAR) + OMT group; log rank test P = 0.15).

AUTHORS' CONCLUSIONS

Overall, the data at two years were insufficient to make any practice recommendations. However, the data on the anatomic remodeling of dissected aortas observed after TEVAR + OMT is encouraging and future studies should follow up cases for at least five years to see if early endovascular interventions, even in stable initially uncomplicated type B patients, are of long-term benefit.

Preliminary findings in quantification of changes in septal motion during follow-up of type B aortic dissections

OBJECTIVE

To quantify longitudinal changes in intra-arterial septum (IS) motion with two-dimensional (2D) phase-contrast magnetic resonance imaging (2D pcMRI) in type B aortic dissections (AD) to improve the understanding of AD and its midterm development.

METHODS

From a database of 42 patients who underwent a dynamic magnetic resonance imaging (MRI) examination at the Acute Aortic Treatment Center of The Methodist DeBakey Heart & Vascular Center, 2D pcMRI image data was available from 10 patients with type B AD for both short-term (mean, 6.6 days; range, 1-10 days; n = 7) and midterm follow-up (mean, 155 days; range, 60-324; n = 5). IS motion was quantified as motion of IS boundary points averaged over the cardiac cycle. Relative change in IS motion was expressed as percent change compared with initial presentation. Maximum IS extension (true lumen [TL] expansion) and contraction (TL compression), IS fraction in phase with aortic flow and correlation of IS motion with aortic flow (IS compliance) were quantified.

RESULTS

IS motion at initial presentation was 0.68 ± 0.2 mm and was reduced at short-term (0.48 ± 0.3 mm; P = .07) and midterm (0.5 ± 0.2 mm; P = .1) follow-up. Trend in relative change of IS motion was variable during short-term follow-up: reduced in three subjects (-75% ± 6%) and elevated in four subjects (48% ± 23%). During midterm follow-up, relative change in IS motion was reduced in four subjects (28% ± 19%) and slightly elevated in one (6.2%). IS contraction decreased with follow-up while IS extension slightly increased. Fraction of IS moving in phase with aortic flow increased but IS compliance decreased, suggesting increasing IS stiffness.

CONCLUSIONS

Reduction of IS motion in AD is seen with short-term and midterm follow-up. Intersubject variability of this trend is high at short-term follow-up but low at midterm follow-up. Detailed analysis of IS motion parameters indicate reduction of IS contraction and IS compliance with time. This has potential implications for endovascular management of type B aortic dissections, as expansion of aortic stent grafts can be limited by a stiff IS.