The INvestigation of STEnt Grafts in Aortic Dissection (INSTEAD) trial: the need for ongoing analysis

Prevention of distal stent graft-induced new entry after endovascular repair for type B aortic dissection: A retrospective cohort study

OBJECTIVES

Distal stent graft-induced new entry (dSINE) can occur after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD). In this study we aimed to compare the effectiveness of restrictive bare stent (RBS), tapered stent graft (TSG), and non-TSG in TEVAR in preventing dSINE after a midterm follow-up.

METHODS

This retrospective cohort study included patients with TBAD who underwent TEVAR (June 2010 to December 2018). The occurrence of dSINE during follow-up was examined. Predictors of dSINE were determined using Fine-Gray regression with death as the competing event. Survival was evaluated using Cox proportional hazards regression.

RESULTS

Finally, 364 patients were included: 111 with non-TSG TEVAR, 125 with TSG TEVAR, and 128 with TEVAR with RBS. After 54.5 months, incidences of dSINE in the 3 groups were 12.61%, 4.80%, and 1.56%, respectively (P = .002). On Fine-Gray regression adjusted for clinically relevant covariates, the expansion mismatch ratio (subdistribution hazard ratio, 1.09; 95% CI, 1.07-1.12; P < .001) and complete false lumen thrombosis (subdistribution hazard ratio, 0.35; 95% CI, 0.13-0.94; P = .037) were identified as predictors of dSINE. The Cox proportional hazards regression analysis revealed that dSINE was not only a risk factor for aortic-related mortality (hazard ratio, 17.90; 95% CI, 3.27-98.12; P = .001), but also a predominant risk factor for all-cause mortality (hazard ratio, 4.91; 95% CI, 1.66-14.52; P = .004).

CONCLUSIONS

dSINE can happen in TBAD patients who undergo TEVAR. Thus, long-term surveillance is crucial. TSG and RBS had lower expansion mismatch ratios, which might help prevent dSINE.

Contemporary Unplanned Readmission Trends Following Management of Type B Aortic Dissection

Purpose

Methods

Results

Conclusion

TEVAR: Endovascular Repair of the Thoracic Aorta

The development of thoracic endovascular aortic repair (TEVAR) has allowed a minimally invasive approach for management of an array of thoracic aortic pathologies. Initially developed specifically for exclusion of thoracic aortic aneurysms, TEVAR is now used as an alternative to open surgery for a variety of disease pathologies due to the lower morbidity of this approach. Advances in endograft technology continue to broaden the applications of this technique.

Volumetric analysis of the initial index computed tomography scan can predict the natural history of acute uncomplicated type B dissections

OBJECTIVE

Our objective was to characterize the predictive impact of computed tomography (CT) scan volumetric analysis on the natural history of acute uncomplicated type B aortic dissections (ADs).

METHODS

We conducted a retrospective review of patients with acute type B ADs from 2009 to 2014. On an iNtuition workstation (TeraRecon, Foster City, Calif), volume measurements were obtained using the true lumen volume (TLV), false lumen volume (FLV), and total aortic volume from the left subclavian artery to the celiac artery. Growth rate was calculated as the change in maximal diameter between first and last available CT scans during the time interval. The primary outcome of the study was delayed aortic intervention. P < .05 was considered statistically significant.

RESULTS

During a 5-year period, 164 patients had CT scan evidence of acute type B ADs; 11 patients were excluded for lack of subsequent follow-up imaging; 36 patients who underwent urgent repair (<14 days from presentation) were also excluded. We evaluated a total of 117 patients: 85 patients who did not require intervention and 32 who underwent delayed (>14 days) thoracic endovascular aneurysm repair (29) or open repair (3). Mean age was 66 ± 12 years. Mean TLV/FLV ratio on initial CT scan was significantly higher in patients who did not eventually require an operation (1.55 vs 0.82; P = .02). The mean growth rate was higher in those eventually requiring operation (2.47 vs 0.42 mm/mo; P = .003). Patients were divided into three subgroups on the basis of their initial imaging TLV/FLV ratios (<0.8, 0.8-1.6, and >1.6). There was a significant difference in the growth rates between these three groups (4.6 vs 2.4 vs 0.8 mm/mo; P < .025). Area under the receiver operating characteristic curve analysis revealed that a TLV/FLV ratio <0.8 was highly predictive for requiring an intervention (area = 0.8; sensitivity, 69%; specificity, 84%: positive predictive value, 71%; negative predictive value, 81%), with an odds ratio of 12.2 (confidence interval, 5-26; P < .001). Conversely, a TLV/FLV ratio of >1.6 was highly predictive for freedom from delayed operation (sensitivity, 91%; specificity, 42%; positive predictive value, 61%; negative predictive value, 86%). After Kaplan-Meier analysis, 1-year and 2-year survival free of aortic interventions was 60% and 42% with a TLV/FLV ratio <0.8 and 92% and 82% with a ratio >1.6 (P = .001).

CONCLUSIONS

Initial CT scan volumetric analysis in patients presenting with uncomplicated acute type B ADs is a useful tool to predict growth and need for future intervention.

Diagnosis and management of thoracic aortic dissection: An update

Acute thoracic aortic dissection is part of the acute aortic syndrome triad. Caused by an intimal tear in the lumen of the aorta, it leads to the creation and propagation of a false lumen. In the acute setting this can lead to malignant hypertension, pain and end organ malperfusion. In the chronic setting it can lead to aneurysm formation and rupture. It remains the most common aortic emergency, affecting up to 4 per 100000 people per year in the United Kingdom and United States. Despite advances in treatment and centralisation of vascular services, it continues to be associated with a high pre-admission and in-hospital mortality. Dissection is classified in several ways according to anatomical extent, timing and underlying pathology, all of which guides clinical management. Traditionally, medical management has been the mainstay of treatment in patients with uncomplicated disease. Surgery has been used in symptomatic patients. With published information now available from several prospective international registries, we are beginning to see the advantages of newer surgical treatment options such as endovascular repair, in the acute setting. This review provides an update on diagnosis and management of aortic dissection, including new information that has become available in recent years.

Long-term outcomes in thoracoabdominal aortic aneurysm repair for chronic type B dissection

INTRODUCTION

Open repair for chronic aortic dissection remains a challenging surgical option. Different centers report diverse experiences and outcomes pertaining to thoracoabdominal aortic aneurysm repair (TAAAR) for chronic type B dissection. We highlight our center's experience and results on a background of published literature and current evidence.

METHODS

We reviewed 214 open TAAAR performed between October 1998 and February 2014. Of these, chronic type B dissection was present in 62 (29.0%) patients. We reviewed these patients in terms of demographics, operative characteristics and outcomes. Thirteen (21.0%) patients had surgery on the descending thoracic aorta [Category A =2 (3.2%), B =0 (0%), C =11 (17.7%)] and 49 (79.0%) in the thoracoabdominal thoracic aorta [Crawford extent I =5 (8.1%), extent II =39 (62.9%), extent III =4 (6.5%), extent IV =1 (1.6%)]. Left heart bypass was used in 12 (19.4%) patients.

RESULTS

The composite in-hospital endpoint, adverse outcome-defined as operative death, renal failure necessitating dialysis at discharge, stroke, or permanent paraplegia or paraparesis-occurred after 28 (45.2%) procedures. There were 14 (22.6%) operative deaths. In-hospital mortality was seven (16.3%) out of 43 elective patients, and increased to seven (36.8%) of the 19 non-elective ones. Permanent paraplegia or paraparesis occurred after two (3.2%) cases, stroke occurred after seven (11.3%) and renal failure requiring dialysis occurred after 16 (25.8%). Mean follow-up time was 3.2 years and actuarial 5-year mortality was 27.4% [nine (14.5%) elective and eight (12.9%) non-elective patients].

CONCLUSIONS

TAAAR in chronic type B dissection carries a substantial risk of early adverse outcomes. The results could be well alleviated with cases directed towards specialized regional and supra-regional centers. Although the endovascular approaches offer relatively low mortality and morbidity, there is a lack of long-term data and guidelines on their use. There is a need for a multidisciplinary international registry on the management of thoracoabdominal aortic aneurysms and dissection. This would provide a degree of guidance on relevant clinical and surgical judgments and outcomes.

Endovascular Versus Medical Therapy for Uncomplicated Type B Aortic Dissection

Background:

Uncomplicated type B dissections have been traditionally managed with antihypertensive therapy. In the endovascular era, this dictum has been revisited. This review pooled the available studies to compare the outcomes of best medical therapy (BMT) to thoracic endovascular aortic repair (TEVAR) for uncomplicated type B dissections.

Methods:

A literature search was performed to identify studies on uncomplicated type B dissections managed with BMT with and without TEVAR. The primary outcome measures were mortality rates at 30 days and at 2 years following intervention.

Results:

A total of 6 studies included 123 patients who underwent TEVAR/BMT, and 566 patients who had BMT alone. The mortality rates at 30 days (6.5% TEVAR/BMT vs 4.8% BMT, P = .21) and at 2 years (9.7% vs 11.9%, P = .32) were similar. Renal failure was greater in TEVAR/BMT (15.4% vs 2.1%, P < .01). Rates of surgical reintervention/intervention were similar (17.6% vs 20.1%, P = .31).

Conclusion:

The TEVAR with BMT does not provide survival benefit compared to BMT alone, 2 years following uncomplicated 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.

Long-Term Outcome of Aortic Dissection With Patent False Lumen

Background—

Patent false lumen in aortic dissection has been associated with poor prognosis. We aimed to assess the natural evolution of this condition and predictive factors.

Methods and Results—

One hundred eighty-four consecutive patients, 108 surgically treated type A and 76 medically treated type B, were discharged after an acute aortic dissection with patent false lumen. Transesophageal echocardiography was performed before discharge, and computed tomography was performed at 3 months and yearly thereafter. Median follow-up was 6.42 years (quartile 1 to quartile 3: 3.31–10.49). Forty-nine patients died during follow-up (22 type A, 27 type B), 31 suddenly. Surgical or endovascular treatment was indicated in 10 type A and 25 type B cases. Survival free from sudden death and surgical-endovascular treatment was 0.90, 0.81, and 0.46 (95% CI, 0.36–0.55) at 3, 5, and 10 years, respectively. Multivariate analysis identified baseline maximum descending aorta diameter (hazard ratio [HR]: 1.32 [1.10–1.59]; P =0.003), proximal location (HR: 1.84 [1.06–3.19]; P =0.03), and entry tear size (HR: 1.13 [1.08–1.2]; P <0.001) as predictors of dissection-related adverse events, whereas mortality was predicted by baseline maximum descending aorta diameter (HR: 1.36 [1.08–1.70]; P =0.008), entry tear size (HR: 1.1 [1.04–1.16]; P =0.001), and Marfan syndrome (HR: 3.66 [1.65–8.13]; P =0.001).

Conclusions—

Aortic dissection with persistent patent false lumen carries a high risk of complications. In addition to Marfan syndrome and aorta diameter, a large entry tear located in the proximal part of the dissection identifies a high-risk subgroup of patients who may benefit from earlier and more aggressive therapy.