Early Results of the PETTICOAT Technique for the Management of Acute Type A Aortic Dissection

Aortic remodelling based on false lumen communications in patients undergoing acute type I dissection repair with AMDS hybrid prosthesis: a substudy of the DARTS trial

OBJECTIVES

The Dissected Aorta Repair Through Stent (DARTS) Implantation trial demonstrated positive proximal aortic remodelling following aortic dissection repair with the AMDS hybrid prosthesis. In this study, we look to identify predictors of aortic remodelling following aortic dissection repair with AMDS including whether communications between branch vessels and the false lumen (FL) predict aortic growth.

METHODS

The DARTS implantation trial included patients who underwent acute DeBakey type I aortic dissection (ATAD I) repair with the AMDS from March 2017 to January 2019. Anatomic measurements were collected from original computerized tomography scans. Measurements were taken at zones 2, 3, 6 and 9. Patients were grouped based on the number of FL communications with the supra-aortic branch vessels or visceral branch vessels.

RESULTS

Forty-seven patients were included in the original DARTS implantation trial. Patients with FL communications with the supra-aortic branch vessels tended to have significant growth at zone 3 (P = 0.02-0.0018), while greater numbers of visceral FL communications tended to predict aortic growth at zones 3 (P = 0.003), 6 (P = 0.017-0.0087) and 9 (P = 0.0016-0.0003).

CONCLUSIONS

Aortic remodelling following ATAD I repair using the AMDS may be predicted by local FL communications with branch vessels. Patients undergoing ATAD I repair were more likely to experience significant aortic growth in zone 3 with more head vessel communications and in zones 3, 6 and 9 with more visceral FL communications. Predictors of aortic remodelling may help to guide initial surgical management for aortic dissection patients.

Quantification of volume changes in the descending aorta after frozen elephant trunk procedure using the Thoraflex hybrid prosthesis for type A aortic dissection

Background

Frozen elephant trunk (FET) is an established approach to reduce late complications of type A aortic dissection (AADA) by diminishing false lumen perfusion. Currently, surface size of aortic lumina are evaluated using Computed tomography (CT). However, this 2D method is prone to error as it evaluates dissection progression slice by slice. Volume measurement on the other hand can overcome this limitation and deliver better insights in aortic remodeling. Therefore, the aim was to quantify volume changes of the descending and abdominal aorta at short- and mid-term follow-up after FET.

Methods

Between April 2015 and March 2018, 20 patients who underwent surgical repair of AADA using the Thoraflex™ Hybrid Plexus (Vascutek, Terumo Aortic, Scotland) were included in this study. We measured volumetric change before surgical treatment, at discharge, at 12 and at 24 months based on CTAs (Computed tomography angiography). Surfaces and volumes have been analyzed using Aquarius iNtuition (TeraRecon Inc., Foster City, CA, USA).

Results

One hundred fifty-eight volumetric measures were obtained. The findings show a significant increase of volume of the true lumen (TL) while surface measurement of the TL did not show any significant change at other levels besides level C (diaphragm, P=0.00193). Variance analysis showed significant increase of volume, whereas no significant change was seen in false lumen. Post-hoc analysis revealed a significance at 24 months (P=0.047).

Conclusions

Although previous studies outline the clinical benefit of Thoraflex hybrid prosthesis on short-term follow up, this study provides a more precise understanding of aortic remodeling based on volumetric measurement. Thus, quantification of volume changes should be included for the assessment of optimal follow-up timing and consecutive procedure planning.

Management of Lower Limb Ischemia During Operative Repair of Acute Type A Aortic Dissection by Distal Crossover Grafts: a Case Series

Objective

To describe our experience of nine patients with extra-anatomical bypass for clinically ischemic distal limb during repair of acute Type A aortic dissection (ATAAD).

Methods

We retrospectively examined a series of nine patients who underwent surgery for ATAAD. We identified a subset of the patients who presented with concomitant radiographic and clinical signs of lower limb ischemia. All but one patient (axillobifemoral bypass) underwent femorofemoral crossover grafting by the cardiac surgeon during cooling.

Results

One hundred eighty-one cases of ATAAD underwent surgery during the study period with a mortality of 19.3%. Nine patients had persistent clinical evidence of lower limb ischemia (4.9%) and underwent extra-anatomical bypass during cooling. Two patients underwent additional fasciotomies. Mean delay from symptoms to surgery in these nine patients was 9.5 hours. Two patients had bilateral amputations despite revascularisation and, of note, had long delays in presentation for surgery (> 12 hours). There were no mortalities during these inpatient episodes. Outpatient radiographic follow-up at the first opportunity demonstrated 100% patency.

Conclusion

Our experience suggests that, during complicated aortic dissection, limb ischemia may have a devastating outcome including amputation when diagnosis and referral are delayed. Early diagnosis and surgery are crucial in preventing this potentially devastating complication.

When to Consider Deferral of Surgery in Acute Type A Aortic Dissection: A Review

Background

Acute type A aortic dissection (ATAAD) is a surgical emergency with an operative mortality of up to 30%, a rate which has not changed meaningfully in over two decades. A growing body of research has highlighted several comorbidities and presenting factors in which delay or permanent deferral of surgery may be considered; however, modern comprehensive summative reviews are lacking. The urgency and timing of this review are underscored by significant challenges in resource utilization posed by the COVID-19 pandemic. This review provides an update on the current understanding of risk assessment, surgical candidacy, and operative timing in patients with ATAAD.

Methods

A literature search was conducted through PubMed and Embase databases to identify relevant studies relating to risk assessment in ATAAD. Articles were selected via group consensus based on quality and relevance.

Results

Several patient factors have been identified which increase risk in ATAAD repair. In particular, frailty, advanced age, prior cardiac surgery, and use of novel anticoagulant medications have been studied. The understanding of malperfusion syndromes has also expanded significantly, including recommendations for surgical delay. Finally, approaches to triage have been significantly influenced by resource limitations related to the ongoing COVID-19 pandemic. While medical management remains a reasonable option in carefully selected patients at prohibitive risk for open surgery, endovascular therapies for treatment of ATAAD are rapidly evolving.

Conclusions

Early surgical repair remains the preferred treatment for most patients with ATAAD, however, improvements in risk stratification should guide appropriate delay or permanent deferral of surgery in select individuals.

Modeling Approach for An Aortic Dissection with Endovascular Stenting

Repair of dissected aorta requires remodeling the structure of the media. Modeling approaches specific to endovascular stenting for aortic dissection have been reported. We created a goat model of descending thoracic aortic dissection and reproduced its morphological characteristics in a mock circulatory system. The purpose of this study was to examine a newly developed aortic stent which was capable of installing to the aortic dissected lesion for biomedical hemodynamics point of view. In this study, we examined the changes in hemodynamics of dissected lesions and the amelioration by endovascular stent intervention. Firstly, we performed animal experiments with the dissected aorta and examined the effects of stenting on volumetric changes in the false lumen. Secondly, we made several types of 3-D stereolithographic dissected aortic models with silicone rubber membrane between the false and the true lumens. Then, the hemodynamic characteristics in each model were evaluated in the pulsatile flow conditions in a mock circulatory system. These modelling approaches enabled the quantitative examination of post-therapeutic effects of stenting followed by elucidating of hemodynamic changes in the vicinity of stents, which may follow the management of clinical amelioration of interventional treatment with aortic stenting.Clinical Relevance- This study represents a modelling approach of the dissected aorta for endovascular intervention using stenting followed by the examination of false lumen volumetric changes resulting in the deterioration of pressure increase in diseased lesions.