Background: Type A aortic dissection (TAAD) involves a tear in the intimal layer of the thoracic aorta proximal to the left subclavian artery, and hence, carries a high risk of mortality and morbidity and requires urgent intervention. This dissection can extend into the main coronary arteries. Coronary artery involvement in TAAD can either be due to retrograde extension of the dissection flap into the coronaries or compression and/or blockage of these vessels by the dissection flap, possibly causing myocardial ischaemia. Due to the emergent nature of TAAD, coronary involvement is often missed during diagnosis, thereby delaying the required intervention. Aims: The main scope of this review is to summarise the literature on the incidence, mechanism, diagnosis, and treatment of coronary artery involvement in TAAD. Methods: A comprehensive literature search was performed using multiple electronic databases, including PubMed, Ovid, Scopus and Embase, to identify and extract relevant studies. Results: Incidence of coronary artery involvement in TAAD was seldom reported in the literature, however, some studies have described patients diagnosed either preoperatively, intraoperatively following aortic clamping, or even during autopsy. Among the few studies that reported on this matter, the treatment choice for coronary involvement in TAAD was varied, with the majority revascularizing the coronary arteries using coronary artery bypass grafting or direct local repair of the vessels. It is well-established that coronary artery involvement in TAAD adds to the already high mortality and morbidity associated with this disease. Lastly, the right main coronary artery was often more implicated than the left. Conclusion: This review reiterates the significance of an accurate diagnosis and timely and effective interventions to improve prognosis. Finally, further large cohort studies and longer trials are needed to reach a definitive consensus on the best approach for coronary involvement in TAAD.

Background While open surgical repair continues to be the mainstay option for aortic arch reconstruction, the associated mortality, morbidity, and high turn-down rates have led to a need for the development of minimally invasive options for aortic arch repair. Though RELAY™ Branched (Terumo Aortic, Inchinnan, UK) represents a promising option for complex endovascular aortic arch repair, neurological complications remain a pertinent risk. Herein we seek to present multi-centre data from Europe documenting the neurological outcomes associated with RELAY™ Branched. Methods Prospective data collected between January 2019 and January 2022 associated with patients treated with RELAY™ single-, double-, and triple-branched endoprostheses from centres across Europe was retrospectively analysed with descriptive and distributive analysis. Follow up data from 30 days and 6-, 12-, and 24 months postoperatively was included. Patients follow up was evaluated for the onset of disabling stroke (DS) and non-disabling stroke (NDS). Results Technical success was achieved in 147 (99.3%) cases. Over 24 months period, in total, 6 (4.1%) patients suffered DS and 8 (5.4%) patients suffered NDS after undergoing aortic arch repair with RELAY™. All patients that developed postoperative DS had been treated with the double-branched RELAY™ endoprosthesis. Discussion The data presented herein demonstrates that RELAY™ Branched is associated with favourable neurological outcomes and excellent technical success rates. Key design features of the endoprosthesis and good perioperative management can contribute greatly to mitigating neurological complications following endovascular aortic arch repair.

Background: There is emerging evidence to support pre-emptive thoracic endovascular aortic repair (TEVAR) intervention for uncomplicated type B aortic dissection (unTBAD). Pre-emptive intervention would be particularly beneficial in patients that have a higher baseline risk of progressing to complicated TBAD (coTBAD). There remains debate on the optimal clinical, laboratory, morphological and radiological parameters which would identify the highest-risk patients that would benefit most from pre-emptive TEVAR. Aim: This review summarises evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients. Methods: A comprehensive literature search was carried out on multiple electronic databases including PubMed, EMBASE, Ovid and Scopus in order to collate all research evidence on the the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients Results: At present, there are no clear clinical guidelines using risk-stratification to inform the selection of unTBAD patients for TEVAR. However, there are noticeable literature trends that can assist with the identification of the most at-risk unTBAD patients. Patients are at particular risk when they have refractory pain and/or hypertension, elevated C-reactive protein (CRP), larger aortic diameter and larger entry tears. These risks should be considered alongside factors that increase the procedural risk of TEVAR to create a well-balanced approach. Advances in biomarkers and imaging are likely to identify more pertinent parameters in future to optimise the development of balanced, risk-stratified treatment protocols. Conclusion: There are a variety of risk profiling parameters that can be used to identify the high-risk unTBAD patient, with novel biomarkers and imaging parameter emerging. Longer-term evidence verifying these parameters would be ideal. Further randomized controlled trials and multicentre registry analyses are also warranted to guide risk-stratified selection protocols.

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.

Background: Uncomplicated type B aortic dissection (un-TBAD) has been managed conservatively with medical therapy in order to control the heart rate and blood pressure to limit disease progression, in addition to radiological follow-up. However, several trials and observational studies have investigated the use of thoracic endovascular aortic repair (TEVAR) in un-TBAD and suggested that TEVAR provides a survival benefit over medical therapy. Outcomes of TEVAR have also been linked with the timing of intervention. Aims: The scope of this review is to collate and summarise all the evidence in the literature on the mid- and long-term outcomes of TEVAR in un-TBAD, confirming its superiority. We also aimed to investigate the relationship between timing of TEVAR intervention and results. Methods: We carried out a comprehensive literature search on multiple electronic databases including PubMed, Scopus and EMBASE in order to collate and summarise all research evidence on the mid- and long-term outcomes of TEVAR in un-TBAD, as well as its relationship with intervention timing. Results: TEVAR has proven to be a safe and effective tool in un-TBAD, offering superior mid- and long-term outcomes including all-cause and aorta-related mortality, aortic-specific adverse events, aortic remodelling, and need for reintervention. Additionally, performing TEVAR during the subacute phase of dissection seems to yield optimal results. Conclusion: The evidence demonstrating a survival advantage in favour TEVAR over medical therapy in un-TBAD means that with further research, particular trials and observational studies, TEVAR could become the gold-standard treatment option for un-TBAD patients.

Background: Uncomplicated Stanford Type B aortic dissection (un-TBAD) is characterised by a tear in the aorta distal to the left subclavian artery without ascending aorta and arch involvement. Optimised cardiovascular control (blood pressure and heart rate) is the current gold standard treatment according to current international guidelines. However, emerging evidence indicates that Thoracic Endovascular Aortic Repair (TEVAR) is both safe and effective in the treatment of un-TBAD with improved long-term survival outcomes in combination with optimal medical therapy (OMT) relative to OMT alone. However, the optimal timeframe for intervention is not entirely clarified. Aims: This review critically addresses current state-of-the-art comparing TEVAR with OMT and corresponding clinical outcomes for un-TBAD based on timing of intervention. Methods: We carried out a comprehensive literature search on multiple electronic databases including PUBMED and Scopus in order to collate all research evidence on timing of TEVAR in uncomplicated Type B aortic dissection. Results: TEVAR has proven to be a safe and effective treatment for un-TBAD in combination with OMT through comparable survival outcomes, improved aortic remodelling, and relatively low periprocedural added risks. Though the timing of intervention remains controversial, it is becoming clear that performing TEVAR during the subacute phase of un-TBAD yields better outcomes compared to earlier and delayed (>90 days) intervention. Conclusions: Further research is required into both short and long-term outcomes of TEVAR in addition to its optimal therapeutic window for un-TBAD. With stronger evidence, TEVAR is likely to be adopted as the gold-standard intervention for un-TBAD with definitive timeframe guidelines.

Thoracic endovascular aortic repair (TEVAR) has quickly become the mainstay of treatment for acute aortic dissection, in particular cases of acute complicated Stanford Type B dissection (co-TBAD). Necessarily, TEVAR carries with it the risk of postoperative complications, including stroke and renal failure. As a result, the management of patients with uncomplicated type B aortic dissection (un-TBAD), which is generally accepted as being less severe, are safely managed via optimal medical therapy (OMT) alone. However, despite OMT, patients with un-TBAD are at substantial risk of severe disease progression requiring delayed intervention. The cost-benefit ratio associated with TEVAR for un-TBAD is therefore of key interest. Howard and colleagues produced a fascinating systematic review and meta-analysis investigating the clinical outcomes of TEVAR for complicated and uncomplicated TBAD. Their data suggests that there is no significant difference in in-hospital mortality or 5-year survival between TEVAR for un-TBAD and co-TBAD, although the 30-day mortality rate appeared to be higher in the co-TBAD cohort. Patients with co-TBAD appeared to also be at a higher risk of postoperative stroke and TEVAR endoleak, while un-TBAD patients were at a higher risk of postoperative renal failure. Further prospective research into these relationships are recommended to fully elucidate the comparative efficacies of TEVAR for un-TBAD and co-TBAD.

Total arch repair (TAR) has become a mainstay of the surgical management of complex pathologies of the ascending aorta and aortic arch, in particular acute Type A aortic dissections (ATAAD). TAR with devices such as the frozen elephant trunk (FET) have been shown to dramatically improve clinical outcomes in such cases. However, TAR with FET remains an immensely challenging procedure, and the risk of debilitating postoperative complications remains high. Spinal cord ischaemia (SCI) and stroke are two particularly tragic adverse outcomes of TAR with FET; it is unsurprising therefore that much research has been done to determine both the underlying cause thereof, and strategies to mitigate this risk. Mousavizadeh and colleagues produced a fascinating systematic review and meta-analysis investigating the relationship between the duration of hypothermic circulatory arrest (HCA) and the risk of developing complications including SCI and stroke. Their data seem to suggest HCA duration is a key factor in causing SCI and stroke following TAR with FET for ATAAD. However, other factors such as stent sizing and landing zone also contribute. Further prospective research into this relationship is recommended to fully elucidate what truly is to blame for these postoperative neurological complications.