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: Initial clinical evaluation (ICE) is traditionally considered a useful screening tool to identify frail patients during the pre-operative assessment. However, emerging evidence supports the more objective assessment of cardiorespiratory fitness (CRF) via cardiopulmonary exercise testing (CPET) to improve surgical risk stratification. Herein, we compared both subjective and objective assessment approaches to highlight the interpretive idiosyncrasies. Methods: As part of routine pre-operative patient contact, patients scheduled for major surgery were prospectively ‘eyeballed’ (ICE) by two experienced clinicians prior to more detailed history taking that also included American Society of Anaesthesiologists score classification. Each patient was subjectively judged to be either ‘frail’ or ‘not frail’ by ICE and ‘fit’ or ‘unfit’ from thorough review of the medical notes. Subjective data were compared against the more objective validated assessment of post-operative outcomes using established CPET ‘cut-off’ metrics incorporating peak pulmonary oxygen uptake ( V̇O 2PEAK), V̇O 2 at the anaerobic threshold ( V̇O 2-AT) and ventilatory equivalent for carbon dioxide that collectively informed risk stratification. These data were retrospectively extracted from a single-centre prospective National Health Service database. Data were analysed using the Chi-square automatic interaction detection decision tree method. Results: A total of 127 patients examined that comprised 58 % male and 42 % female patients aged 69 ± 10 y with a BMI of 29 ± 7 kg/m 2. Patients were poorly conditioned with a peak pulmonary oxygen uptake almost 20 % lower than that predicted for age, sex-matched healthy controls with 35 % exhibiting a V̇O 2-AT <11 mL/kg/min. Disagreement existed between the subjective assessments of risk with ~34 % of patients classified not frail on ICE were considered unfit by notes review ( P < 0.0001). Furthermore, ~35 % of patients considered not frail on ICE and ~31 % of patients considered fit by notes review exhibited a V̇O 2-AT <11 mL/kg/min and of these, ~28 % and ~19 % were classified as intermediate-to-high risk. Conclusions: These findings highlight the interpretive limitations associated with the subjective assessment of patient frailty with surgical risk classification underestimated in up to a third of patients compared to the validated assessment of CRF. They reinforce the benefits of a more objective and integrated approach offered by CPET that may help improve perioperative risk assessment and better direct critical care provision in patients scheduled for ‘high-stakes’ surgery including open TAAA repair.

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 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 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, false lumen 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.

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.