Multidisciplinary team-led management of acute Type B aortic dissection in the United Kingdom?

Uncomplicated Type B Aortic Dissection: Challenges in Diagnosis and Categorisation

BACKGROUND

Acute type B aortic dissection (TBAD) is a rare disease that is likely under-diagnosed in the UK. As a progressive, dynamic clinical entity, many patients initially diagnosed with uncomplicated TBAD deteriorate, developing end-organ malperfusion and aortic rupture (complicated TBAD). An evaluation of the binary approach to the diagnosis and categorisation of TBAD is needed.

METHODS

A narrative review of the risk factors predisposing patients to progression from unTBAD to coTBAD was undertaken.

RESULTS

Key high-risk features predispose the development of complicated TBAD, such as maximal aortic diameter > 40 mm and partial false lumen thrombosis.

CONCLUSION

An appreciation of the factors that predispose to complicated TBAD would aid clinical decision-making surrounding TBAD.

The misnomer of uncomplicated type B aortic dissection

BACKGROUND

Acute type B aortic dissection (TBAD) is a rare condition that can be divided into complicated (CoTBAD) and uncomplicated (UnCoTBAD) based on certain presenting clinical and radiological features, with UnCoTBAD constituting the majority of TBAD cases. The classification of TBAD directly affects the treatment pathway taken, however, there remains confusion as to exactly what differentiates complicated from uncomplicated TBAD.

AIMS

The scope of this review is to delineate the literature defining the intervention parameters for UnCoTBAD.

METHODS

A comprehensive literature search was conducted using multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on intervention parameters and protocols for UnCoTBAD.

RESULTS

A TBAD without evidence of malperfusion or rupture might be classified as uncomplicated but there remains a subgroup who might exhibit high-risk features. Two clinical features representative of "high risk" are refractory pain and persistent hypertension. First-line treatment for CoTBAD is TEVAR, and whilst this has also proven its safety and effectiveness in UnCoTBAD, it is still being managed conservatively. However, TBAD is a dynamic pathology and a significant proportion of UnCoTBADs can progress to become complicated, thus necessitating more complex intervention. While the "high-risk" UnCoTBAD do benefit the most from TEVAR, yet, the defining parameters are still debatable as this benefit can be extended to a wider UnCoTBAD population.

CONCLUSION

Uncomplicated TBAD remains a misnomer as it is frequently representative of a complex ongoing disease process requiring very close monitoring in a critical care setting. A clear diagnostic pathway may improve decision making following a diagnosis of UnCoTBAD. Choice of treatment still predominantly depends on when an equilibrium might be reached where the risks of TEVAR outweigh the natural history of the dissection in both the short- and long-term.

Criteria for endovascular intervention in type B aortic dissection

BACKGROUND

The use of thoracic endovascular aortic repair (TEVAR) for the management of uncomplicated type B aortic dissection (un-TBAD) remains controversial. There is a lack of consensus over whether pre-emptive TEVAR should be carried out in patients with un-TBAD at risk of progression to complicated TBAD. We present a review of current evidence and seek to suggest criteria where endovascular intervention in un-TBAD may prove beneficial relative to pharmacotherapy alone.

METHODS AND MATERIALS

PubMed and Cochrane databases were searched using terms including: type B aortic dissection, risk factors, medical therapy, TEVAR, false lumen (FL) expansion, and mortality. Papers were selected based on title and abstract.

RESULTS

Optimal medical therapy remains the mainstay treatment for patients with un-TBAD, however, patients with un-TBAD present with varying degrees of disease progression risk. Factors such as age, aortic morphology, history of connective tissue disorders, FL thrombosis, and aortic branch involvement may potentiate progression from un-TBAD to complicated TBAD. Short- and long-term outcomes associated with TEVAR for TBAD remain promising.

CONCLUSION

Pre-emptive TEVAR may be beneficial in patients with un-TBAD presenting with the above factors, however, further prospective research into the optimal timing for TEVAR in un-TBAD is required.

Thoracic endovascular aortic repair for uncomplicated Type B aortic dissection: What is the optimal time window for intervention?

BACKGROUND

Uncomplicated Type B aortic dissection (un-TBAD) is still managed conservatively with optimal medical therapy (OMT) despite evidence in favour of thoracic endovascular aortic repair (TEVAR) for un-TBAD. OMT aims to regulate heart rate and blood pressure and patients require long-term follow-up to evaluate the extent of dissection, however, many un-TBAD patients are lost to follow-up. Several trials and observational studies evaluated the use of TEVAR in combination with OMT in un-TBAD and proved the safety, effectiveness, and comparability of TEVAR relative to OMT alone. What remains in question is the optimal time window to intervene with TEVAR. This was recently addressed in a fascinating review by Jubouri et al. AIMS: This commentary aims to discuss the recent review by Jubouri et al. which further proved that TEVAR is safe and effective in un-TABD and investigated the optimal timing of TEVAR in un-TBAD.

MATERIALS & METHODS

We carried out a literature search using multiple electronic databases including PUBMED and Scopus in order to collate research evidence on intervention timeframe and outcomes of TEVAR in un-TBAD.

RESULTS

Performing TEVAR during the subacute phase of dissection (15-90 days since symptom onset) seems to be associated with less periprocedural complications compared to the acute phase, however, late outcomes (>30 days post-TEVAR) are comparable between the two groups and are superior to the chronic phase.

DISCUSSION

The introduction of TEVAR in un-TBAD presents a paradigm shift in the management of un-TBAD and a potential move towards becoming the gold-standard treatment option for un-TBAD. Intervening with TEVAR within the first 90 days since symptom onset (acute and subacute un-TBAD) gives favourable outcomes relative to intervention in the chronic phase of dissection (>90 days since symptom onset), this is due to the dissecting septum becoming less compliant over time.

CONCLUSION

TEVAR is a safe and effective treatment modality for un-TBAD with a survival benefit compared to OMT alone. Offering TEVAR during the subacute phase of dissection yields optimal results which are comparable to the acute phase but superior to the chronic phase.

Vascular Teams in Peripheral Vascular Disease

Peripheral vascular disease affects millions of individuals worldwide, and results in significant morbidity and mortality. The complex nature of the disease, the presence of multiple comorbidities, and the existence of a wide variety of therapeutic options suggests that a multidisciplinary approach to treatment has the potential to improve care of these patients. The success of the heart team for complex coronary artery and structural heart disease could serve as a model for the efficient and effective management of patients with peripheral vascular disease. In this paper, the authors propose a multidisciplinary vascular team approach for the treatment of critical limb ischemia, pulmonary embolism, acute ischemic stroke, and acute aortic syndromes. The successful implementation of such vascular teams has the potential to significantly enhance quality of care, improve clinical outcomes, and reduce costs. Prospective evaluation is warranted to determine how to best integrate this approach into routine clinical care.