Fate of the Dissected Thoraco-Abdominal Aorta Distal to TEVAR (Thoracic Endovascular Aortic Repair) for Complicated Acute and Subacute Type B Aortic Dissection

Purpose: This study assessed morphological changes in the aortic true and false lumens during follow-up of patients undergoing TEVAR (Thoracic Endovascular Aortic Repair) for complicated acute and subacute type B dissection. The study analyzes the effectiveness of TEVAR in preventing distal aneurysmal progression. Materials and Methods: All patients between 2009 and 2019 undergoing TEVAR for complicated acute and subacute type B dissection at the study institution were retrospectively reviewed. Maximal diameters were measured on the proximal descending aorta right below the left subclavian artery, thoraco-abdominal junction right above the celiac trunk, and infrarenal aortic right above the inferior mesenteric artery, pre-operatively and during follow-up, analyzing either expansion or shrinkage of true and false lumens at these 3 sites. Results: Forty-one patients were included. Thirty-day incidence of death, stroke, paraplegia, and visceral ischemia was, respectively, 8% (n = 4), 6% (n = 3), 2% (n = 1), and 2% (n = 1). Three patients (6%) died from intervention-related cause. Mortality was 17% (n = 8) during a mean follow-up of 54 months. One patient had aneurysmal dilation of the descending aorta needing additional coverage and only 2 (4%) developed thoraco-abdominal aneurysms requiring re-intervention. In the remaining patients, both significant expansion of the true lumen and shrinkage of false lumen were observed at all 3 sites. Conclusion: Proximal coverage of the main entry tear appears to prevent aneurysmal progression in most patients (96%). With such promising results, TEVAR should be considered as a first-line treatment in acute and subacute type B dissection.

Computational Fluid Dynamic Technique for Assessment of How Changing Character of Blood Flow and Different Value of Hct Influence Blood Hemodynamic in Dissected Aorta

Using computer tomography angiography (CTA) and computational structural analysis, we present a non-invasive method of mass flow rate/velocity and wall stress analysis in type B aortic dissection. Three-dimensional (3D) computer models of the aorta were calculated using pre-operative (baseline) and post-operative CT data from 12 male patients (aged from 51 to 64 years) who were treated for acute type B dissection. A computational fluid dynamics (CFD) technique was used to quantify the displacement forces acting on the aortic wall in the areas of endografts placement. The mass flow rate and wall stress were measured and quantified using the CFD technique. The CFD model indicated the places with a lower value of blood velocity and shear rate, which corelated with higher blood viscosity and a probability of thrombus appearance. Moreover, with the increase in Hct, blood viscosity also increased, while the intensity of blood flow provoked changing viscosity values in these areas. Furthermore, the velocity gradient near the tear surface caused high wall WSS; this could lead to a decreased resistance in the aorta’s wall with further implications to a patient.

747 A Case Report: Spontaneous Recovery of Type B Aortic Dissection

Introduction An aortic dissection occurs when there is a tear in the intimal and medial layer of the aorta, leading to a false lumen within the media. Type B aortic dissections (TBAD), according to the Stanford Classification are where the entry tear is located distally from the left subclavian artery. Resolution of a Type B aortic dissection (TBAD) by medical therapy is a very rare event. Case Presentation 58-year-old gentleman presented with sudden onset central chest pain. A CTPA was organised following a high d-dimer. This showed a TBAD extending from the origin of the left subclavian artery to the level of the diaphragm. His blood pressure was aggressively controlled with IV labetalol and IV isosorbide dinitrate and was monitored for 2 weeks. He was then discharged home on oral antihypertensive medication. A follow up CT aortogram was done 7 months later which showed that the false lumen of the TBAD has improved from 18mm to 2 mm. Discussion The anti-inotropic effect of beta blockers reduces the stress on the aortic wall and therefore prevents further dilatation. Aggressive control of blood pressure and heart rate comes with its own disadvantages. It had been shown, patients managed conservatively were more likely to develop renal failure (43%) compared to those having endovascular repair. About half of those patients required surgical treatment. There are not many cases in literature where a TBAD had resolved with medication. Conclusions As evident from this case, rigorous management of blood pressure may help with cases of Type B Dissection.

4D flow MRI of type B dissection with later retrograde progression to type A dissection in Marfan: a case report

Background Due to the malfunction of connective tissue, Marfan patients are at increased risk of aortic dissection. Uncomplicated acute type B dissection is usually managed with medical therapy. Retrograde progression or new type A dissection is a relatively rare but often fatal complication that occur most frequently in the first 6 months after acute type B dissection. Case summary We present a 31-year-old male with Marfan syndrome and a recent uncomplicated type B dissection from the left subclavian to the right common iliac artery who underwent 4D flow magnetic resonance imaging (MRI). The dissection had a large proximal intimal tear just distal to the left subclavian artery (15 mm) and large false lumen (35 mm). Aortic blood flow just distal to the left subclavian artery (3.6 L/min) was split disproportionately into the true (0.8 L/min, 22%) and false lumen (2.8 L/min, 78%). 4D flow streamlines revealed vortical flow in the proximal false lumen. Increased wall shear stress was observed at the sinotubular junction (STJ), inner wall of the ascending aorta and around the subclavian artery. Two weeks after MRI, the patient presented with jaw pain. Computed tomography showed a type A dissection with an entry tear at the STJ for which an acute valve-sparing root, ascending and arch replacement was performed. Discussion Better risk assessment of life-threatening complications in uncomplicated type B dissections could improve treatment strategies in these patients. Our case demonstrates that besides clinical and morphological parameters, flow derived parameters could aid in improved risk assessment for retrograde progression from uncomplicated type B dissection to acute type A dissection.

Clinical outcomes of the Frozen Elephant Trunk procedure in 70 emergent and elective patients undergoing aortic arch surgery: the Salerno experience with Thoraflex Hybrid

Background and aim of the study. To report early clinical outcomes of the frozen elephant trunk technique (FET) for the treatment of complex aortic diseases after transition from conventional elephant trunk. Methods. A single-center, retrospective study of patients who underwent hybrid aortic arch and FET repair for aortic arch and/or proximal descending aortic aneurysms, acute and chronic Stanford type A aortic dissection with arch and/or proximal descending involvement, Stanford type B acute and chronic aortic dissections with retrograde aortic arch involvement. Results. Between December 2017 and May 2020, 70 consecutive patients (62.7±10.6 years, 59 male) were treated: 41 (58.6%) for acute conditions and 29 (41.4%) for chronic. Technical success was 100%. In-hospital mortality was 14.2% (n=12, 17.1% emergency vs. 10.3% chronic, P=NS); 2 (2.9%) major strokes; 1 (1.4%) spinal cord injury. Follow-up was 12.5 months (IQR 3.7—22.3. Overall survival at 3, 6, 12 and 24 months was 90% (95% CI, 83.2—97.3), 85.6% (95% CI, 77.7—94.3), 79.1% (95% CI, 69.9—89.5), 75.6% (95% CI, 65.8—86.9) and 73.5 (95% CI, 63.3—85.3). There were no aortic re-interventions and no dSINE; 5 patients with residual type B dissection underwent TEVAR completion. Conclusions. In a real-world setting, FET demonstrated a rapid learning curve and good clinical outcomes, even in acute type A aortic dissections. Techniques to perfect the procedure and to reduce remaining risks, and consensus on considerations such as standardized cerebral protection need to be reported.

Is TEVAR Really Needed for Uncomplicated Type B Aortic Dissection?

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.

Simple Hepatic Cysts as Markers of Thoracic Aortic Disease

Objective: Thoracic Aortic Disease (TAD) is potentially lethal, yet difficult to detect as most patients are asymptomatic until the aneurysm dissects and becomes life threatening. Several clinical markers for TAD have been identified such as: bicuspid aortic valve, intracranial aortic aneurysm, bovine aortic arch, positive family history, and simple renal cysts. The aim of this study was to investigate the prevalence of Simple Hepatic Cysts (SHC) among individuals diagnosed with TAD in order to assess whether they can be used as a predictor of TAD. Methods: In this retrospective study, the prevalence of SHC for (n=1244) hospital patients treated for TAD was evaluated and compared to a control group of (n=809) patients. TAD patients were divided into four subgroups: ascending aneurysm (788; 63.3%; descending aneurysm (123; 9.9%); type A dissection (137; 11%); type B dissection (196; 15.8%). The presence of SHC was determined based on either computed tomography, magnetic resonance imaging, or ultrasound imaging of these patients. Results: Prevalence of SHC was 14.8%, 11.4%, 12.4%, and 14.8% in patients with ascending aneurysm, descending aneurysm, type A dissection, and type B dissection, respectively. Prevalence of SHC in the control group was 3.8% (p<0.001). The prevalence of SHC was not significantly different between males and females among the TAD patients as well as the control population. Conclusion: Individuals with TAD have an increased prevalence of SHC compared to individuals without TAD. SHC can potentially be used as a clinical marker to detect patients at risk for TAD.