Effects of the patent false lumen on the long-term outcome of type B acute aortic dissection

A Systematic Review and Meta-Analysis of Current Evidence Related to the Impact of Endovascular Repair Timing on Prognosis of Acute Stanford Type B Aortic Dissection

BACKGROUND

The objective of this study was to determine whether thoracic endovascular aortic repair (TEVAR) timing is more beneficial in the acute phase (first 14 days) than in the subacute phase (14-90 days) for the administration of acute Stanford type B aortic dissection (TBAD).

METHODS

A comprehensive literature search was conducted in databases (EMBASE, PubMed and Cochrane Library) until December 2023 to identify studies reporting the results of TEVAR used for patients with acute TBAD. Odds ratios (ORs) with 95% confidence intervals (CIs) were estimated utilizing either the random-effects model or the fixed-effects model.

RESULTS

A total of 25 studies involving 4,827 individuals with TBAD (including 1,609 with subacute TBAD) met our selection criteria. Early results revealed a lower incidence of Ia endoleaks (OR, 1.55; 95% CI, 1.03-2.33; P = 0.04) and aortic ruptures (OR, 2.89; 95% CI, 0.98-8.50; P = 0.05) in subacute TBAD. Apart from these findings, there was little difference in other incidents between the 2 groups. Regarding late outcomes, we observed significantly higher rates of retrograde dissection (OR, 2.12; 95% CI, 1.04-4.34; P = 0.04), distal stent-induced new entry (OR, 2.39; 95% CI, 1.24-4.61; P = 0.009), and reintervention (OR, 1.45; 95% CI, 0.05-1.99; P = 0.02) in acute TBAD than in subacute TBAD, whereas no significant differences were found for other outcomes between the 2 groups. Also, TEVAR appeared to yield comparable results for false lumen thrombosis and true lumen regression in both groups.

CONCLUSIONS

Subacute TBAD repair with TEVAR demonstrates a more effective reduction in adverse event rates compared to immediate treatment in the acute phase.

False lumen hemodynamics and partial thrombosis in chronic aortic dissection of the descending aorta

OBJECTIVES

Partial thrombosis of the false lumen (FL) in patients with chronic aortic dissection (AD) of the descending aorta has been associated with poor outcomes. Meanwhile, the fluid dynamic and biomechanical characteristics associated with partial thrombosis remain to be elucidated. This retrospective, single-center study tested the association between FL fluid dynamics and biomechanics and the presence and extent of FL thrombus.

METHODS

Patients with chronic non-thrombosed or partially thrombosed FLs in the descending aorta after an aortic dissection underwent computed tomography angiography, cardiovascular magnetic resonance (CMR) angiography, and a 4D flow CMR study. A comprehensive quantitative analysis was performed to test the association between FL thrombus presence and extent (percentage of FL with thrombus) and FL anatomy (diameter, entry tear location and size), fluid dynamics (inflow, rotational flow, wall shear stress, kinetic energy, and flow acceleration and stasis), and biomechanics (pulse wave velocity).

RESULTS

Sixty-eight patients were included. In multivariate logistic regression FL kinetic energy (p = 0.038) discriminated the 33 patients with partial FL thrombosis from the 35 patients with no thrombosis. Similarly, in separated multivariate linear correlations kinetic energy (p = 0.006) and FL inflow (p = 0.002) were independently related to the extent of the thrombus. FL vortexes, flow acceleration and stasis, wall shear stress, and pulse wave velocity showed limited associations with thrombus presence and extent.

CONCLUSION

In patients with chronic descending aorta dissection, false lumen kinetic energy is related to the presence and extent of false lumen thrombus.

CLINICAL RELEVANCE STATEMENT

In patients with chronic aortic dissection of the descending aorta, false lumen hemodynamic parameters are closely linked with the presence and extent of false lumen thrombosis, and these non-invasive measures might be important in patient management.

KEY POINTS

• Partial false lumen thrombosis has been associated with aortic growth in patients with chronic descending aortic dissection; therefore, the identification of prothrombotic flow conditions is desirable. • The presence of partial false lumen thrombosis as well as its extent was related with false lumen kinetic energy. • The assessment of false lumen hemodynamics may be important in the management of patients with chronic aortic dissection of the descending aorta.

Prognostic impact of oral anticoagulation therapy and atrial fibrillation in patients with type B acute aortic dissection

Background

The prognostic impact of atrial fibrillation (AF) and oral anticoagulation (OAC) therapy in patients with type B acute aortic dissection (AAD) remains unclear. Therefore, we investigated the prognostic impact of AF and OAC therapy in patients with type B AAD.

Methods

Consecutive patients diagnosed with AAD were included in this single-center, retrospective study. Patients with type B AAD were selected from the study population and divided into three groups: AF(+)/OAC(+), AF(+)/OAC(-), and AF(-)/OAC(-). The primary end point was major adverse cardiovascular and cerebrovascular events (MACCE), including all-cause death, progressive aortic events, cerebral infarction, and organ malperfusion.

Results

In total, 139 patients diagnosed with type B AAD were analyzed. AF was observed in 27 patients (19%). Among them, 13 patients (9%) received OAC therapy for AF. MACCE occurred in 32 patients (23%) during the observation period: all-cause death in four patients, progressive aortic events in 24 patients, cerebral infarction events in two patients, and malperfusion events in two patients. The incidence of MACCE was higher in the AF(+)/OAC(+) group than in the AF(+)/OAC(-) group (hazard ratio[HR]: 3.875; 95% confidence interval [CI]: 1.153-17.496). In contrast, there was no significant difference in the incidence of MACCE between the AF(+)/OAC(-) and AF(-)/OAC(-) groups (HR: 1.001, 95% CI: 0.509-1.802).

Conclusion

Among patients with type B AAD, the use of OAC for AF was associated with a higher risk of MACCE.

Clinical comparative analysis of 3D printing-assisted extracorporeal pre-fenestration and Castor integrated branch stent techniques in treating type B aortic dissections with inadequate proximal landing zones

BACKGROUND

This study aims to compare the clinical effects of two distinct surgical approaches, namely 3D printing-assisted extracorporeal pre-fenestration and Castor integrated branch stent techniques, in treating patients with Stanford type B aortic dissections (TBAD) characterized by inadequate proximal landing zones.

METHODS

A retrospective analysis was conducted on 84 patients with type B aortic dissection (TBAD) who underwent thoracic endovascular aortic repair (TEVAR) with left subclavian artery (LSA) reconstruction at our center from January 2022 to July 2023. Based on the different surgical approaches, the patients were divided into two groups: the group assisted by 3D printing for extracorporeal pre-fenestration (n = 44) and the group using the castor integrated branch stent (n = 40). Clinical indicators: including general patient information, operative time, surgical success rate, intraoperative and postoperative complication rates, re-intervention rate, and mortality, as well as postoperative aortic remodeling, were compared between the two groups. The endpoint of this study is the post-TEVAR mortality rate in patients.

RESULTS

The surgical success rate and device deployment success rate were 100% in both groups, with no statistically significant difference (P > 0.05). However, the group assisted by 3D printing for extracorporeal pre-fenestration had a significantly longer operative time (184.20 ± 54.857 min) compared to the group using the castor integrated branch stent (152.75 ± 33.068 min), with a statistically significant difference (t = 3.215, p = 0.002, P < 0.05). Moreover, the incidence of postoperative cerebral infarction and beak sign was significantly lower in the group assisted by 3D printing for extracorporeal pre-fenestration compared to the castor-integrated branch stent group, demonstrating statistical significance. There were no significant differences between the two groups in terms of other postoperative complication rates and aortic remodeling (P > 0.05). Notably, computed tomography angiography images revealed the expansion of the vascular true lumen and the reduction of the false lumen at three specified levels of the thoracic aorta. The follow-up duration did not show any statistically significant difference between the two groups (10.59 ± 4.52 vs. 9.08 ± 4.35 months, t = 1.561, p = 0.122 > 0.05). Throughout the follow-up period, neither group experienced new endoleaks, spinal cord injuries, nor limb ischemia. In the castor-integrated branch stent group, one patient developed a new distal dissection, prompting further follow-up. Additionally, there was one case of mortality due to COVID-19 in each group. There were no statistically significant differences between the two groups in terms of re-intervention rate and survival rate (P > 0.05).

CONCLUSION

Both 3D printing-assisted extracorporeal pre-fenestration TEVAR and castor-integrated branch stent techniques demonstrate good safety and efficacy in treating Stanford type B aortic dissection with inadequate proximal anchoring. The 3D printing-assisted extracorporeal pre-fenestration TEVAR technique has a lower incidence of postoperative cerebral infarction and beak sign, while the castor-integrated branch stent technique has advantages in operative time.

Mechanical Versus Bioprosthetic Aortic Valve Replacement in Patients Undergoing Bentall Procedure

BACKGROUND

The widely used Bentall procedure is the criterion standard treatment for aortic root pathology. Studies comparing the long-term outcomes of bioprosthetic and mechanical valves in patients undergoing the Bentall procedure are limited.

METHODS AND RESULTS

Patients who underwent the Bentall procedure with a bioprosthetic or mechanical valve between 2001 and 2018 were identified from Taiwan's National Health Insurance Research Database. The primary outcome of interest was all-cause mortality. Inverse probability of treatment weighting was performed to compare the 2 prosthetic types. In total, 1052 patients who underwent the Bentall procedure were identified. Among these patients, 351 (33.4%) and 701 (66.6%) chose bioprosthetic and mechanical valves, respectively. After inverse probability of treatment weighting, no significant differences in the in-hospital mortality (odds ratio, 0.96 [95% CI, 0.77-1.19]; P=0.716) and all-cause mortality (34.1% vs. 38.1%; hazard ratio, 0.90 [95% CI, 0.78-1.04]; P=0.154) were observed between the groups. The benefits of relative mortality associated with mechanical valves were apparent in younger patients and persisted until ≈50 years of age.

CONCLUSIONS

No differences in survival benefits were observed between the valves in patients who underwent the Bentall procedure. Additionally, bioprosthetic valves may be a reasonable choice for patients aged >50 years when receiving the Bentall procedure in this valve-in-valve era.

Prognostic impact of early aortic volume changes at hospital discharge in patients with acute type B aortic dissection

BACKGROUND

Early prediction of aorta-related events is important for determining subsequent treatment strategies in patients with acute aortic dissection. However, most studies evaluated long-term aortic growth rates by annual assessment. The purpose of our study was to determine whether the in-hospital growth rate of aortic volume was associated with aorta-related events.

METHODS

We studied 116 patients with uncomplicated type B acute aortic dissection. We analyzed whether changes in aortic volume were associated with aorta-related events during a 5-year follow-up. According to the growth rate from admission to discharge, patients were divided into two groups: Increase >0 (aortic volume: n = 59, aortic diameter: n = 43) and Reduction ≤0 (aortic volume: n = 57, aortic diameter: n = 73) in maximum aortic diameter or aortic volume. The primary endpoint was the discriminative ability of the growth rate of aortic volume for aorta-related events.

RESULTS

According to the evaluation of aortic volume changes, the Increase group had significantly higher aorta-related event rates than those in the Reduction group (49.2 % vs. 3.5 %, respectively; p < 0.001). Receiver operating characteristics analysis showed that the growth rate of aortic volume had a clearly useful discrimination, with an area under the curve of 0.84, whereas the discriminative ability of the growth rate of maximum aortic diameter was poor (area under the curve: 0.53). Multivariate analysis showed that the growth rate of aortic volume from admission to discharge was an independent predictor of aorta-related events (hazard ratio, 26.3; 95 % confidence interval, 2.04-286.49; p = 0.001).

CONCLUSIONS

In-hospital evaluation of aortic volume was helpful to predict long-term aorta-related events in patients with uncomplicated type B acute aortic dissection.

Stent-Assisted Balloon-Induced Intimal Disruption and Relamination in Aortic Dissection Repair (STABILISE): A Meta-Analysis of Early Outcomes

BACKGROUND

This meta-analysis aims to determine the early clinical outcomes and rate of complete false lumen obliteration associated with the stent-assisted balloon-induced intimal disruption and relamination in aortic dissection repair (STABILISE) technique in the management of aortic dissection.

METHODS

Electronic databases searches were performed on PubMed, Embase, and the Cochrane Library to identify studies reporting early outcomes of the STABILISE technique. In addition, we retrospectively analyzed all patients treated with the STABILISE technique for aortic dissection at our institution. The case series data were pooled with relevant studies to perform a meta-analysis of proportions using random-effects models.

RESULTS

One hundred and ninety two patients from 9 relevant studies were pooled with an additional 13 patients undergoing STABILISE at our institution over a 3-year period. Pooled in-hospital mortality rate was 6% [95% confidence interval (CI); 3%-10%, I2 = 0.00%] and the overall rate of intraoperative aortic rupture was 4% [95% CI; 2%-8%, I2 = 0.00%]. The rate of in-hospital reintervention was 8% [95% CI; 5%-14%, I2 = 13.37%]. Median follow-up ranged from 8 to 36 months. Pooled cumulative mortality at follow-up was 8% [95% CI; 4%-18%, I2 = 23.15%]. The overall rate of late reintervention was 11% [95% CI; 7%-17%, I2 = 0.00%]. Complete obliteration of the false lumen in the thoracic aorta was achieved in 93% of patients [95% CI; 84%-97%, I2 = 47.49%] and in the abdominal aorta in 86% of patients [95% CI; 79%-91%, I2 = 0.00%].

CONCLUSIONS

The STABILISE technique carries an acceptable operative safety profile with low in-hospital morbidity and mortality and excellent complete false lumen obliteration.

Thoracic Endovascular Aortic Repair on Zone 2 Landing for Uncomplicated Type B Aortic Dissection with Measurement of Intra-False Lumen Pressure

BACKGROUND

This study aimed to evaluate the midterm results of zone 2 thoracic endovascular aortic repair (TEVAR) for uncomplicated type B aortic dissection (TBAD) by measuring the intra-false lumen pressure (IFLP) during TEVAR.

METHODS

Fifteen patients (9 men; mean age, 57 years) who underwent zone 2 TEVAR for uncomplicated TBAD were reviewed. Delta systolic pressure (defined as the difference between systemic pressure and IFLP) was measured before and after primary entry closure, and aortic remodeling and thrombo-occlusion of the false lumen (FL) were evaluated 12 months after TEVAR at 5 different levels of the aorta.

RESULTS

Median duration from onset to TEVAR was 34 days. The left subclavian artery was preserved in 13 patients (87%) by using stent graft fenestration. Although 1 patient (6%) had a transient cerebral infarction, there were no severe TEVAR-related complications. Entry closure significantly reduced delta systolic pressure (mm Hg) compared to preoperative pressure at all levels (distal arch: -22.2 ± 10.8 vs. -5.2 ± 9.6; Th8: -20.1 ± 12.4 vs. -6.9 ± 7.2; Th10: -14.3 ± 14.6 vs. -4.7 ± 7.5; Th12: -14.4 ± 14.5 vs. -4.9 ± 7.8; L2: -14.5 ± 14.2 vs. -3.4 ± 6.9). The percentages of aortic remodeling with expansion of the true lumen (distal arch: 82%; Th8: 80%; Th10: 54%; Th12: 45%; L2: 50%) and complete false lumen thrombosis (distal arch: 100%; Th8: 100%; Th10: 67%; Th12: 11%; L2: 0%) were approximately consistent with the change in delta systolic pressure. During a follow-up of 41 months, distal stent-induced new entry occurred in 2 patients (13%) requiring secondary intervention; however, there were no cases of FL enlargement or aorta-related mortality.

CONCLUSIONS

Zone 2 TEVAR for uncomplicated TBAD may prevent TEVAR-related complications. Measuring IFLP could be a new predictive marker for assessing the extent of aortic remodeling.

Comprehensive review of aortic aneurysms, dissections, and cardiovascular complications in connective tissue disorders

Connective tissue disorders, including Marfan syndrome (MS) and Ehlers-Danlos syndrome (EDS), are characterized by genetic mutations affecting connective tissue structural integrity. These disorders significantly elevate the risk of aortic dissection, a life-threatening condition. This comprehensive review delves into the intricate interplay between connective tissue disorders and aortic dissection, shedding light on the clinical features, pathophysiology, genetic underpinnings, diagnostic approaches, clinical management, associated comorbidities, and prognosis, mainly focusing on MS and EDS, while also exploring rare connective tissue disorders and forms of cutis laxa contributing to aortic pathology.

Outcomes of symptomatic penetrating aortic ulcer and intramural hematoma in the endovascular era

BACKGROUND

Although endovascular technology has resulted in a paradigm shift in treatment, medical management remains the standard of care for penetrating aortic ulcer (PAU) and intramural hematoma (IMH). This study aimed to detail the short- and long-term outcomes of symptomatic PAU/IMH.

METHODS

Institutional data on symptomatic PAU/IMH were gathered (2005-2020). The primary outcome was the composite of recurrent symptoms, radiographic progression, intervention, rupture, and death from related or unknown cause. Factors associated with the primary outcome were determined using a Fine-Gray model with death from an unrelated cause as a competing risk.

RESULTS

A total of 83 symptomatic patients treated with medical management aside from ruptures and type A dissections: 21 isolated PAU, 30 isolated IMH, and 32 IMH and PAU. Adverse outcomes included symptom recurrence in 14 (16.9%), radiographic progression to dissection or saccular aneurysm in 17 (20.5%), surgery in 20 (24.1%) (17 thoracic endovascular aortic repair, 1 endovascular aortic repair, 1 frozen elephant trunk, and 1 open repair), and rupture in 4 (4.8%). Twenty-seven patients (32.5%) died during follow-up: 6 from IMH treatment complications, 8 from an unknown cause, and 13 from other causes. The 30-day, 1-year, and 5-year cumulative incidences of the primary outcome was 26.5% (95% confidence interval [CI], 16.9%-37.0%), 44.9% (95% CI, 32.8%-56.2%), and 57.5% (95% CI, 42.4%-69.9%), respectively. IMH with PAU was associated with a significantly higher risk of the primary outcome compared with isolated IMH (subdistribution hazard ratio, 2.21; 95% CI, 1.09-4.50; P = .027) and isolated PAU (subdistribution hazard ratio, 3.58; 95% CI, 1.44-8.88; P = .006).

CONCLUSIONS

Complications from symptomatic PAU and IMH are frequent, with intervention, recurrent symptoms, radiographic progression, rupture, or death affecting 25% of patients at 30 days after diagnosis and almost one-half of patients 1 year after diagnosis. Given the high rate of adverse events in this population, investigation into a more aggressive interventional strategy may warranted, especially in patients with a combined IMH and PAU.

Impact of antithrombotic therapy on clinical outcomes in patients with type B acute aortic syndrome

Objective

Antithrombotic therapy has the potential to interfere with false lumen thrombosis. In type B acute aortic syndrome, the degree of false lumen thrombosis affects clinical outcomes. We aimed to explore the association of antithrombotic therapy with the prognosis of patients with type B acute aortic syndrome.

Methods

We reviewed 406 patients with type B acute aortic syndrome who were discharged alive with and without antithrombotic therapy. The primary outcome was aorta-related adverse events, defined as a composite of aorta-related death, aortic rupture, aortic repair, and progressive aortic dilation.

Results

Of the 406 patients, 64 (16%) were discharged with antithrombotic therapy and 342 (84%) were discharged without antithrombotic therapy. A total of 249 patients (61%) presented with intramural hematoma with complete thrombosis of the false lumen, and 157 patients (39%) presented with aortic dissection. During a median follow-up of 4.6 years, 32 patients (50%) in the antithrombotic group and 93 patients (27%) in the nonantithrombotic group had a primary outcome event. Cumulative incidence of aorta-related events at 1 and 3 years with death as the competing risk was higher in the antithrombotic group than in the nonantithrombotic group (19% ± 5% vs 9% ± 2% at 1 year and 40% ± 7% vs 17% ± 2% at 3 years, P < .001).

Conclusions

Antithrombotic therapy might be associated with an increased risk of aorta-related events in patients with type B acute aortic syndrome.

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.

Intervention rates and outcomes in medically managed uncomplicated descending thoracic aortic dissections

OBJECTIVE

To evaluate the long-term incidence and outcome of aortic interventions for medically managed uncomplicated thoracic aortic dissections.

METHODS

Between January 2012 and December 2018, 91 patients were discharged home with an uncomplicated, medically treated aortic dissection (involving the descending aorta with or without aortic arch involvement, no ascending involvement). After a median period of 4 (first quartile: 2, third quartile: 11) months, 30 patients (33%) required an aortic intervention. Patient characteristics, radiographic, treatment, and follow-up data were compared for patients with and without aortic interventions. A competing risk regression model was analyzed to identify independent predictors of aortic intervention and to predict the risk for intervention.

RESULTS

Patients who underwent aortic interventions had significantly larger thoracic (P = .041) and abdominal (P = .015) aortic diameters, the dissection was significantly longer (P = .035), there were more communications between both lumina (P = .040), and the first communication was significantly closer to the left subclavian artery (P = .049). A descending thoracic aortic diameter exceeding 45 mm was predictive for an aortic intervention (P = .001; subdistribution hazard ratio: 3.51). The risk for aortic intervention was 27% ± 10% and 36% ± 11% after 1 and 3 years, respectively. Fourteen patients (47%) underwent thoracic endovascular aortic repair, 11 patients (37%) thoracic endovascular aortic repair and left carotid to subclavian bypass, 3 patients (10%) total arch replacement with the frozen elephant trunk technique, and 2 patients (7%) thoracoabdominal aortic replacement. We observed no in-hospital mortality.

CONCLUSIONS

The need for secondary aortic interventions in patients with initially medically managed, uncomplicated descending aortic dissections is substantial. The full spectrum of aortic treatment options (endovascular, hybrid, conventional open surgical) is required in these patients.

Morphological parameters affecting false lumen thrombosis following type B aortic dissection: a systematic study based on simulations of idealized models

Type B aortic dissection (TBAD) carries a high risk of complications, particularly with a partially thrombosed or patent false lumen (FL). Therefore, uncovering the risk factors leading to FL thrombosis is crucial to identify high-risk patients. Although studies have shown that morphological parameters of the dissected aorta are related to FL thrombosis, often conflicting results have been reported. We show that recent models of thrombus evolution in combination with sensitivity analysis methods can provide valuable insights into how combinations of morphological parameters affect the prospect of FL thrombosis. Based on clinical data, an idealized geometry of a TBAD is generated and parameterized. After implementing the thrombus model in computational fluid dynamics simulations, a global sensitivity analysis for selected morphological parameters is performed. We then introduce dimensionless morphological parameters to scale the results to individual patients. The sensitivity analysis demonstrates that the most sensitive parameters influencing FL thrombosis are the FL diameter and the size and location of intimal tears. A higher risk of partial thrombosis is observed when the FL diameter is larger than the true lumen diameter. Reducing the ratio of the distal to proximal tear size increases the risk of FL patency. In summary, these parameters play a dominant role in classifying morphologies into patent, partially thrombosed, and fully thrombosed FL. In this study, we point out the predictive role of morphological parameters for FL thrombosis in TBAD and show that the results are in good agreement with available clinical studies.

Shear-driven modelling of thrombus formation in type B aortic dissection

Background: Type B aortic dissection (TBAD) is a dangerous pathological condition with a high mortality rate. TBAD is initiated by an intimal tear that allows blood to flow between the aortic wall layers, causing them to separate. As a result, alongside the original aorta (true lumen), a false lumen (FL) develops. TBAD compromises the whole cardiovascular system, in the worst case resulting in complete aortic rupture. Clinical studies have shown that dilation and rupture of the FL are related to the failure of the FL to thrombose. Complete FL thrombosis has been found to improve the clinical outcomes of patients with chronic TBAD and is the desired outcome of any treatment. Partial FL thrombosis has been associated with late dissection-related deaths and the requirement for re-intervention, thus the level of FL thrombosis is dominant in classifying the risk of TBAD patients. Therefore, it is important to investigate and understand under which conditions complete thrombosis of the FL occurs.

Method: Local FL hemodynamics play an essential role in thrombus formation and growth. In this study, we developed a simplified phenomenological model to predict FL thrombosis in TBAD under physiological flow conditions. Based on an existing shear-driven thrombosis model, a comprehensive model reduction study was performed to improve computational efficiency. The reduced model has been implemented in Ansys CFX and applied to a TBAD case following thoracic endovascular aortic repair (TEVAR) to test the model. Predicted thrombus formation based on post-TEVAR geometry at 1-month was compared to actual thrombus formation observed on a 3-year follow-up CT scan.

Results: The predicted FL status is in excellent agreement with the 3-year follow-up scan, both in terms of thrombus location and total volume, thus validating the new model. The computational cost of the new model is significantly lower than the previous thrombus model, with an approximate 65% reduction in computational time. Such improvement means the new model is a significant step towards clinical applicability.

Conclusion: The thrombosis model developed in this study is accurate and efficient at predicting FL thrombosis based on patient-specific data, and may assist clinicians in choosing individualized treatments in the future.

Risk profile analysis of uncomplicated type B aortic dissection patients undergoing thoracic endovascular aortic repair: Laboratory and radiographic predictors

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 remain 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 summarizes 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 to collate all research evidence on 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 the future to optimize 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 parameters 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.

Ratio of the false lumen to the true lumen is associated with long-term prognosis after surgical repair of acute type A aortic dissection

Objectives

The aim of this study was to assess potential predictors of aortic events after an emergency surgery for acute type A aortic dissection, especially paying attention to the findings of computed tomography (CT) performed immediately after the surgery.

Methods

Between January 2001 and December 2015, 72 patients, who were diagnosed as having Stanford type A acute aortic dissection with a patent false lumen in the descending thoracic aorta, survived the emergency operation, and had postoperative CT scan data, were included in this study (mean follow-up, 8.2 ± 3.8 years; range 0.8-17.4 years). From the CT scan data, the diameter of the false lumen (FL-D) and true lumen (TL-D) were measured, and the FL-D:TL-D ratio was calculated. Long-term outcomes of the FL-D > TL-D group (n = 30) and the FL-D < TL-D group (n = 42) were compared.

Results

In the late follow-up, 17 aortic events in the downstream aorta were observed. The FL-D:TL-D ratio (P = .01) was an adjusted risk of aortic events in multivariable analysis. The rates of freedom from aortic events at 5 and 9 years were superior in the FL-D < TL-D group than in the FL-D > TL-D group (92.0% and 88.6% vs 81% and 60.7%; log rank P < .05).

Conclusions

Our results suggest that the false lumen:true lumen ratio predicts long-term prognosis after surgical repair of acute type A aortic dissection.

Systematic review and meta-analysis of current evidences in endograft therapy versus medical treatment for uncomplicated type B aortic dissection

OBJECTIVE

Best medical therapy (BMT) should be recommended for treating uncomplicated Stanford type B aortic dissection (uSTBAD), whereas thoracic aortic endovascular repair (TEVAR) has been controversial for uSTBAD.

METHODS

In this paper, a meta-analysis was conducted on all available randomized controlled trials and observational studies that evaluated the relative benefits and harms of TEVAR and BMT for the management of patients suffering from uSTBAD. Primary endpoints consisted of early adverse events, long-term adverse events and aortic remodeling. In addition, Risk difference (RD) or Odds ratios (OR) with 95% confidence intervals (CI) were estimated. The random effects model or the fixed-effects model was used in accordance with the 50% heterogeneity threshold.

RESULTS

Seven observational studies and two RCT studies from 11 articles that contained 15066 patients suffering from uSTBAD (1518 TEVARs) met the inclusion criteria. For early outcomes, no significant differences were found between the TEVAR group and the BMT group in aortic rupture, retrograde dissection, paraplegia/paraparesis, reintervention, aorta-related death and all caused death. In the long run, the TEVAR group was found to have a significantly lower incidence of adverse events, which included aortic rupture (OR:0.26, CI:0.16∼0.42, P<0.05; heterogeneity: P=0.90, I²=0%), reintervention (OR:0.45, CI:0.26∼0.75, P<0.05; heterogeneity: P=0.17, I²=41%), aorta-related death (OR:0.27, CI:0.18∼0.42, P<0.05; heterogeneity: P=0.61, I²=0%) and all caused death (OR:0.52, CI:0.42∼0.66, P<0.05; heterogeneity: P=0.05, I²=53%) as compared with the BMT group. Moreover, in compared with BMT, TEVAR was found to significantly contribute to the complete thrombosis of thoracic false lumen (OR:55.34, CI:34.32∼89.21, P<0.05; heterogeneity: P=0.97, I²=0%) and aortic regression (true lumen expansion and false lumen shrinkage).

CONCLUSIONS

Although early endovascular repair of uSTBAD does not outperform BMT, its implementation is found to be necessary to facilitate the long-term prognosis. Accordingly, if early TEVAR is to be deferred, close follow-up is critical to allow for timely reintervention.

Descending Aorta Diameters as Predictor of Late Adverse Outcomes in Patients with Uncomplicated Type B Aortic Dissection: A Systematic Review and Meta-Analysis

BACKGROUND

A subset of patients with uncomplicated type B aortic dissection (uTBAD) has been shown to possess higher risk of experiencing late adverse outcomes. Therefore, we conducted an analysis to investigate the role of descending aorta diameters, including total descending aorta diameter and false lumen diameter, as predictor of late adverse outcomes in patients with uTBAD.

METHODS

A systematic search was performed through Pubmed, ClinicalKey, ScienceDirect, and Cochrane Library to identify relevant studies. Our primary outcome was the composite late adverse events following their first episode of hospitalization. All meta-analyses were performed using Review Manager version 5.4.

RESULTS

A total of 2,339 (male 68.8%) patients from a total of 15 cohorts were included in our analysis. During follow-up period, there were 655 (27.3%) and 149 (6.3%) cases of late adverse events and mortality, respectively. Patients with higher initial descending aorta diameter were at higher risk of developing late adverse events (RR 2.99 [2.60, 3.44]; P < 0.001) and mortality (RR 3.15 [2.34, 4.25]; P <0.001) throughout follow-up period. Maximum false lumen diameter at the initial presentation seemed to significantly be associated with late adverse events (RR 1.87 [1.46, 2.39]; P <0.001) but not with mortality (RR 2.55 [0.81-8.00; P = 0.11).

CONCLUSION

Descending aorta diameters, particularly maximum initial descending aorta diameter, is a good and helpful predictor of late adverse outcomes in patients with uTBAD.

Proximal False Lumen Thrombosis is Associated with Low False Lumen Pressure and Fewer Complications in Type B Aortic Dissection

BACKGROUND

Improved risk stratification is a key priority for type B aortic dissection (TBAD). Partial false lumen thrombus morphology is an emerging predictor of complications however, partial thrombosis is poorly defined and its evaluation in clinical studies is inconsistent.

PURPOSE

This work aims to characterise hemodynamic pressure in TBAD and determine how pressure relates to false lumen thrombus morphology and clinical events.

METHODS

Retrospective admission computed tomography angiography of 69 patients with acute TBAD was used to construct three-dimensional computational models for simulation of cyclical blood flow and calculation of pressure. Patients were categorised based on false lumen thrombus morphology: minimal; proximal; distal; or extensive thrombosis. Linear regression analysis compared the luminal pressure difference between the true and false lumen for each morphology group. The impact of morphology classification on acute complications within 14 days was studied using logistic regression adjusted for clinical parameters. A survival analysis for adverse aortic events at one-year was also performed using Cox regression.

RESULTS

44 patients experienced acute complications and 45 had an adverse aortic event at one-year. Mean (±standard deviation) age was 62.6 (±12.6) years and 75.4% were male. Compared to patients with minimal thrombosis, those with proximal thrombosis had reduced false lumen pressure by 10.1mmHg (95% CI 4.3-15.9mmHg, p=.001). Individuals that did not experience an acute complication had reduced relative false lumen pressure (-6.35mmHg vs -0.62mmHg, p=.03). Proximal thrombosis was associated with fewer acute complications (OR 0.17, 95% CI 0.04-0.60 p=.01) and one-year adverse aortic events (HR 0.36, 95% CI 0.16-0.80, p=.01).

CONCLUSIONS

Proximal false lumen thrombosis is a marker of reduced false lumen pressure. This may explain how proximal false lumen thrombosis appears protective of acute complications (refractory hypertension or pain, aortic rupture, visceral or limb malperfusion and acute expansion) and adverse aortic events within the first year.

Endovascular solution in a complex post-dissectional thoracic aortic aneurysm case

A 45-year-old male patient presented to our clinic with a post-dissectional thoracic aortic aneurysm with the retrograde filling of the false lumen. He previously underwent a Bentall operation and a proximal thoracic endovascular aortic repair. We carried out a bare metal stent implantation concomitant with endograft extension and stent-assisted balloon-induced intimal disruption and relamination procedure consecutively. Although true lumen expansion was achieved, the aneurysmatic dilation of the descending thoracic aorta was kept on expanding due to perfusion of the false lumen by the distal re-entries. Therefore, it was decided to perform a totally false lumen thrombosis by the candy-plug technique. In conclusion, despite being a fatal disease, endovascular treatment of post-dissectional thoracic aortic aneurysm post-dissectional thoracic aortic aneurysm is possible in anatomically suitable patients with a stepwise approach in experienced endovascular centers.

Aortic enlargement in two weeks is associated with subsequent aortic events in patients with type B acute aortic syndrome

OBJECTIVES

To determine whether aortic enlargement in 2 weeks in patients with type B acute aortic syndrome is associated with aorta-related adverse events.

METHODS

This retrospective, single-center study included 183 patients who were diagnosed with uncomplicated type B acute aortic syndrome (classic aortic dissection and intramural hematoma) between 2010 and 2019 and had follow-up computed tomography at second or third week. Aortic diameter was measured at admission and at predischarge follow-up. Aorta-related adverse events were defined by a composite of aortic rupture, surgical or endovascular aortic repair, redissection, severe intestinal malperfusion, and aortic enlargement.

RESULTS

The patients whose aortic diameter enlarged ≥2 mm but <5 mm in 2 weeks were categorized as moderate aortic enlargement group. During follow-up, 51 patients (28%) had aorta-related adverse events and 36 patients (20%) had moderate aortic enlargement. Patients with moderate aortic enlargement showed lower aorta-related event-free survival rates than those without moderate enlargement (48 ± 9% vs 90 ± 3% at 1 year, P < .001). On multivariable analysis, moderate aortic enlargement (subhazard ratio, 3.64; 95% confidence interval, 2.08-6.35; P < .001) and aortic diameter ≥40 mm at admission (subhazard ratio, 2.96; 95% confidence interval, 1.60-5.48; P < .001) were associated with aorta-related adverse events.

CONCLUSIONS

Moderate aortic enlargement in 2 weeks is a significant risk factor of aorta-related adverse events in patients with uncomplicated type B acute aortic syndrome. Patients with moderate aortic enlargement should be followed up carefully and may be candidates for subsequent endovascular treatment.

Outflow Through Aortic Side Branches Drives False Lumen Patency in Type B Aortic Dissection

Objective: Thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) aims to induce false lumen (FL) thrombosis by sealing intimal tears between the true (TL) and the FL, and blocking the inflow into the FL. Incomplete thrombosis of the FL is correlated with poor clinical outcome. We hypothesize that the number of major and minor branches arising from the FL affects FL patency and may negatively influence TEVAR induced FL thrombosis.

Methods: Computed tomography (CT)-scans from 89 patients diagnosed with TBAD [best medical treatment (BMT) n = 52, TEVAR n = 37] from two high-volume vascular surgery centers were analyzed retrospectively. Analysis included evaluation of the FL patency status, the number, location and size of intimal tears, and the presence of minor and major side branches originating from the FL. Multiple regression analysis was conducted to evaluate obtained parameters as predictors for FL thrombosis status.

Results: In univariate analysis, the strongest correlation for FL patency was found for the number of major (R = 0.79) and minor (R = 0.86) side branches originating from the FL. When applying a multiple linear regression model, the number of major (normalized beta 0.37; P < 0.001) and minor (normalized beta 0.41; P < 0.01) side branches arising from the FL were valid predictors for the axial length of the patent and non-patent FL, and additionally determined the length of the patent FL at 12-month follow-up in patients that underwent TEVAR.

Conclusions: Our data suggest that the number of minor side branches that originate from the FL in TBAD is an important determinant of FL patency, to a greater degree than previously assumed.

Extended Stent Coverage Decreases Distal Aortic Segmental Enlargement After the Endovascular Repair of Acute Complicated Type B Aortic Dissection: A Multi-Center Retrospective Study of 814 Patients

PURPOSE

This study aimed to investigate the effect of distal aortic segmental enlargement (DASE) after thoracic endovascular aortic repair for complicated type B aortic dissection (cTBAD).

MATERIALS AND METHODS

From March 2003 to October 2018, 814 patients with acute cTBAD from 5 medical centers were retrospectively identified. DASE is indicated as the enlargement of distal aortic segmental volume ≥1.6 fold of the preoperative volume compared with the most recent postoperative computed tomography angiography (CTA) scan. Of these patients, 635 (78%) were identified as non-DASE, and 179 (22%) were identified as DASE. Competing risk analysis was performed to compare late death and distal aortic reintervention between the groups. The morphological variables and false lumen thrombosis at 7 aortic levels were measured based on the preoperative CTA and the most recent CTA. Univariate and multivariate Cox regression analyses were used to assess the independent predictors of DASE.

RESULTS

The mean follow-up time of the entire cohort was 5.6 years (interquartile range: 2.4-8.3 years). There were total of 208 late deaths, including 94 (14.8%) deaths in non-DASE group versus 114 (63.7%) deaths in the DASE group. Distal aortic reintervention was observed in 89 patients, with 43(6.7%) in the non-DASE group versus 46 (25.7%) in the DASE group. The cumulative incidence of late death and distal aortic reintervention were significantly higher in the DASE than in the non-DASE group (p<0.001). In morphological analysis, significant incomplete false lumen thrombosis was observed in all distal aortic segments above the aortic level of celiac artery (p<0.01). According to multivariate analysis, the Marfan syndrome, stent coverage to the level of diaphragm and the level of celiac artery were independent predictors of the DASE (p<0.001). Patients with extended stent coverage to the level of celiac artery have shown a lower incidence of DASE (p<0.010).

CONCLUSION

Compared with the non-DASE group, patients with DASE demonstrated a higher rate of late death and distal aortic reintervention. For the cTBAD population, extended stent-graft coverage to the aortic section between diaphragm and celiac artery might serve as a "cost-efficient" cutoff point aiming to reduce the risk of DASE.

Penetration of Dissected Membrane for False Lumen Embolization in a Case of Chronic Aortic Dissection

Background: Patent false lumens carry a high risk of aortic events including rupture. False lumen embolization is a useful method to promote thrombosis of false lumen. In the case presented here, direct penetration of the dissected membrane was employed to obtain access to the false lumen, enabling embolization. Case report: The case was a 64-year-old female who developed a Stanford type A acute aortic dissection. Replacement of ascending aorta and aortic arch with frozen elephant trunk technique was performed. After the operation, there was a residual flow through the false lumen in the descending thoracic and abdominal aorta. Twenty months later, the patient complained of sudden back pain, and a CT scan demonstrated another new dissection at the distal edge of the open stent. Additionally, the false lumen that had remained since the onset of the type A aortic dissection enlarged during the observation period. An endovascular procedure was planned to exclude the false lumen. Despite closing all communicating channels between true and false lumen using a vascular plug, coils, and stent grafts, the false lumen continued to expand due to the residual flow at the visceral segment. The origin responsible for the flow was not identified. To perform an embolization of the false lumen, access into the false lumen was obtained by penetration of the dissected flap using a trans-septal needle. Following the successful penetration of the flap, embolization of the false lumen was performed using coils and glue. After the embolization, an angiogram of the false lumen confirmed the significant reduction of leakage into the true lumen. The size of the aorta and false lumen decreased after the embolization. Conclusion: Direct penetration of the dissected membrane of the aorta was a safe and useful measure for regaining access to the false lumen and for the following endovascular intervention.

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.

A S-Shaped Association of Distal Oversizing Ratio with Distal Stent-Graft-Induced New Entry Following Thoracic Endovascular Aortic Repair for Stanford B Aortic Dissection

BACKGROUND

This study was performed to evaluate the nonlinear association of the distal oversizing ratio with distal stent-graft-induced new entry (dSINE) following thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) and to find the optimal value of the distal oversizing ratio for prevention strategy of dSINE.

METHODS

Total of 177 patients who underwent TEVAR for TBAD from the Registry Of type B aortic dissection with the Utility of STent graft were retrospectively investigated. Patients were stratified into two groups on the median distal oversizing ratio: lower group (≤16%, n = 88) and higher group (>16%, n = 89). The Kaplan-Meier method was used to estimate the cumulative incidence of dSINE. The multivariate Cox proportional hazards model was used to identify the association of the distal oversizing ratio with dSINE. Restricted cubic smoothing spline plots and two-piecewise regression were used to analyze the possible nonlinear association.

RESULTS

Eleven patients developed dSINE (6.21%) during the median follow-up time of 12.37 months (interquartile range, 8.07-18.17 months). An S-shaped association of the distal oversizing ratio with dSINE was identified. When the distal oversizing ratio was ≤40%, the risk of dSINE increased with distal oversizing ratio, and the risk of dSINE was highest when the distal oversizing ratio reached 40% (adjusted HR, 1.09; 95% CI, 1.02-1.17; P = 0.011). A larger distal oversizing ratio over 40% did not generate a greater risk of dSINE (adjusted HR, 0.95; 95% CI, 0.87-1.05; P = 0.455).

CONCLUSIONS

This study substantiated previous findings that the dSINE was associated with the increasing distal oversizing ratio. We also found an S-shaped association between the distal oversizing ratio and dSINE after TEVAR for TBAD. The distal oversizing ratio of 40% can be used for stratified management of patients who underwent TEVAR for TBAD.

Timing and Outcome of Endovascular Repair for Uncomplicated Type B Aortic Dissection

OBJECTIVE

This study aimed to determine the effect of intervention timing, from symptom onset to thoracic endovascular aortic repair (TEVAR), on early and late outcomes in high risk patients with uncomplicated type B aortic dissection (uTBAD).

METHODS

The study retrospectively evaluated 267 uTBAD patients with high risk radiographic features who underwent pre-emptive TEVAR during the acute and subacute periods. Demographics, comorbidities, pre-operative imaging features, peri-procedural details, and follow up outcomes were analysed.

RESULTS

Among the 267 pre-emptive TEVARs for high risk uTBAD, 130 were performed in the acute phase (1-14 days); and 137 in the subacute phase (15-90 days), from initial presentation. The mean age was 55.9 ± 11.0 years and 222 (83.1%) were men. The 30 day mortality rate in the acute group was five times higher than that in the subacute group (3.8% vs. 0.7%), although without statistically significant difference (p = .11). No statistically significant difference in 30 day outcomes (aortic rupture, retrograde type A dissection [RTAD], immediate type Ia endoleak, stroke, spinal cord ischaemia, and re-intervention) was noted (p > .05 for each). Of note, aortic rupture, RTAD, and disabling stroke were observed only in the acute group. Multivariable logistic analyses showed that intervention timing was not associated with 30 day outcomes. The median clinical follow up was 48.2 ± 25.9 months (range 1 - 106 months). There were no significant differences in all cause mortality, dissection related death, late intervention, or aortic related late events among timing cohorts (p > .05 for each). Furthermore, aortic remodelling, by analysing the flow status of the false lumen and evaluation of aortic diameters, either at the thoracic aorta level or the abdominal aorta level, was similar between the two groups. Multivariable Cox analyses showed that intervention timing was not associated with late outcomes.

CONCLUSION

The present study indicates that TEVAR for high risk uTBAD in the acute phase was associated with a trend toward higher rates of early complications, while the long term outcomes were comparable with those of the subacute phase.

Relationship Between Heart Rate at Discharge and Long-Term Outcomes of Surgically Treated Patients With Type A Acute Aortic Dissections

BACKGROUND

Resting heart rate (HR) at discharge is an important predictor of mortality after acute myocardial infarction. However, in patients with Stanford type A acute aortic dissections (TA-AADs), the relationship between HR and long-term outcomes is unclear. Therefore, this relationship was investigated in the present study.Methods and Results:Surgically treated consecutive patients with TA-AAD (n=721) were retrospectively categorized according to HR quartiles, recorded within 24 h before discharge (<70, 70-77, 78-83, and ≥84 beats/min). The study endpoints included aortic aneurysm-related deaths, sudden deaths, aortic surgeries, and hospitalizations for recurrence of acute aortic dissections. The mean (±SD) patient age was 65.8±13.0 years. During a median observation period of 5.8 years (interquartile range 3.9-8.5 years), 17.2% of patients (n=124) experienced late aortic events. Late aortic surgery was performed in 14.0% of patients. After adjusting for potential confounders, including β-blocker use, HR at discharge remained an independent predictor of long-term aortic outcomes. Patients with discharge HR ≥84 beats/min had a higher risk (hazard ratio 1.86; 95% confidence interval 1.06-3.25; P=0.029) of long-term aortic events than those with HR <70 beats/min; the cumulative survival rates were similar among the groups (log-rank, P=0.905).

CONCLUSIONS

In surgically treated patients with TA-AAD, HR at discharge independently predicted long-term aortic outcomes. Consequently, HR in patients with TA-AAD should be optimized before discharge, particularly if the HR is ≥84 beats/min.

Analysis of MCM Proteins' Role as a Potential Target of Statins in Patients with Acute Type A Aortic Dissection through Bioinformatics

Acute aortic dissection is one of the most severe vascular diseases. The molecular mechanisms of aortic expansion and dissection are unclear. Clinical studies have found that statins play a protective role in aortic dissection development and therapy; however, the mechanism of statins' effects on the aorta is unknown. The Gene Expression Omnibus (GEO) dataset GSE52093, GSE2450and GSE8686 were analyzed, and genes expressed differentially between aortic dissection samples and normal samples were determined using the Networkanalyst and iDEP tools. Weight gene correlation network analysis (WGCNA), functional annotation, pathway enrichment analysis, and the analysis of the regional variations of genomic features were then performed. We found that the minichromosome maintenance proteins (MCMs), a family of proteins targeted by statins, were upregulated in dissected aortic wall tissues and play a central role in cell-cycle and mitosis regulation in aortic dissection patients. Our results indicate a potential molecular target and mechanism for statins' effects in patients with acute type A aortic dissection.

Long-term fate of aortic branches in patients with aortic dissection

OBJECTIVE

Late morbidity and mortality related to aortic branches in patients with aortic dissection (AD) have not been well described. We investigated the fate of aortic branches in a population cohort of patients with newly diagnosed AD.

METHODS

We used the Rochester Epidemiology Project record linkage system to identify all Olmsted County, Minnesota, residents with a diagnosis of AD from 1995 to 2015. Only patients with >30 days of available follow-up imaging studies were included in the present analysis. The primary outcome was freedom from any branch-related event (any intervention, aneurysm, malperfusion, rupture, or death occurring after the acute phase >14 days). The secondary outcome was the diameter change in the aortic branches. Univariate and multivariable Cox proportional hazards models were used to identify the predictors of branch-related events. Univariate and multivariate linear regression models were used to assess the aortic branch growth rate.

RESULTS

Of 77 total incident AD cases, 58 patients who had survived and had imaging follow-up studies available were included, 28 (48%) with type A and 30 (52%) with type B AD. The presentation was acute in 39 patients (67%), 6 (10%) of whom had had branch malperfusion. Of 177 aortic branches involved by the AD, 81 (46%) had arisen from the true lumen, 33 (19%) from the false lumen, and 63 (36%) from both. After the acute phase, freedom from any branch-related event at 15 years was 48% (95% confidence interval [CI], 32%-70%). A total of 31 branch-related events had occurred in 19 patients within 15 years, including 12 interventions (76% freedom; 95% CI, 63%-92%), 10 aneurysms (67% freedom; 95% CI, 50%-90%), 8 cases of malperfusion (76% freedom; 95% CI, 61%-94%), and 1 rupture (94% freedom; 95% CI, 84%-100%). No branch-related deaths had occurred. Type B AD (hazard ratio [HR], 3.5; 95% CI, 1.1-10.8; P = .033), patency of the aortic false lumen (HR, 6.8; 95% CI, 1.1-42.2; P = .038), and malperfusion syndrome at presentation (HR, 6.0; 95% CI, 1.3-28.6; P = .023) were predictors of late aortic branch-related events. The overall growth rate of aortic branches was 1.3 ± 3.0 mm annually. Patency of the aortic false lumen, initial branch diameter, and Marfan syndrome were significantly associated with diameter increase.

CONCLUSIONS

In patients with AD, aortic branch involvement was responsible for significant long-term morbidity, without any related mortality. Type B AD, patency of the aortic false lumen, and malperfusion syndrome at presentation resulted in a greater risk of branch events during the long-term follow-up. Dilatation of the aortic branches was observed in one third of cases during follow-up, especially in the case of a patent aortic false lumen or the presence of Marfan syndrome.

False lumen embolization as a rescue technique in the setting of acute and chronic dissecting aneurysms as adjunct to thoracic endovascular aortic repair

Complicated type B aortic dissection (TBAD) is a life-threatening condition requiring surgical intervention. One such complication in the acute or chronic setting is aneurysmal degeneration. The dissected aortic wall is weakened, and the pressures in the false lumen are often high. In the past decade, thoracic endovascular aortic repair (TEVAR) has become the treatment of choice for TBAD. TEVAR can be complicated by lack of false lumen thrombosis, increasing the risk of death. We present three cases of TBAD with patent false lumens after TEVAR that were treated by false lumen coil embolization.

Anticoagulant and anti-thrombotic therapy in acute type B aortic dissection: when real-life scenarios face the shadows of the evidence-based medicine

Background

Evidence-based recommendations about anticoagulation in acute type B aortic dissection (TBAD) are completely missing, but there is a diffuse conviction that it could prevent the healing process of the dissected aorta’s false lumen. However, several clinical conditions may lead to the necessity to start anticoagulant therapy among patients with acute type B aortic dissection, ranging from atrial fibrillation to more complicated clinical scenarios and the correct management in this kind of patients is still an open issue.

Case presentation

We are presenting a 51-years-old man with multi-infarct encephalopathy referred to us for an acute TBAD and a first diagnosis of ischemic cardiomyopathy complicated by left ventricular (LV) thrombus formation. Coronary angiography revealed a critical stenosis of left anterior descending artery (LAD) treated with drug-eluting stent deployment. The patient was addressed to triple antithrombotic therapy with acetylsalicylic acid, clopidogrel and warfarin with target INR 2.0–2.5. After 6 months, computed tomography angiography revealed the stability of the dissection flap. Cardiac magnetic resonance imaging, however, confirmed the persistence of a small thrombotic formation in LV apex, thus double antithrombotic therapy with warfarin and clopidogrel was instituted. The patient remained asymptomatic during the follow-up period but was advised to suspend his job and physical activities.

Conclusion

Current guidelines do not discuss anticoagulant therapy in the setting of TBAD and large randomized trials are lacking. Despite it is generally considered unsafe to administer anticoagulants in patients with TBAD, we present a case in which triple antithrombotic therapy was well tolerated and did not lead to progression of the intimal flap after 6 months.

Surgical Strategies for Type B Aortic Dissection by Frozen Elephant Trunk

The timing and choice of surgical method for type B aortic dissection, is still a topic of much debate. We performed total arch replacement using frozen elephant trunk (TAR-FET) as a means of preventing distant aortic events, such as retrograde type A aortic dissection (RTAD). We conducted analysis of 142 patients with acute type B dissection who were admitted between January of 2010 and July of 2017. Fifty-five cases required surgical intervention to treat enlargement of the false lumen diameter and ULP formation 2 weeks after the onset of symptoms. 17 TAR-FET were performed with a mean of 42±26 days period from onset to surgery. There were no complications of RTAD or paraplegic, and 90% of patient demonstrated aortic event free survival (5 years) and false lumen reduction ratio of 35%. Based on our analysis, using TAR-FET properly avoids serious complications like RTAD, and is a viable treatment option for type B dissection. (This is a translation of J Jpn Coll Angiol 2018; 58: 151-157.).

Intermediate fenestrations reduce flow reversal in a silicone model of Stanford Type B aortic dissection

Pulsatile, three-dimensional hemodynamic forces influence thrombosis, and may dictate progression of aortic dissection. Intimal flap fenestration and blood pressure are clinically relevant variables in this pathology, yet their effects on dissection hemodynamics are poorly understood. The goal of this study was to characterize these effects on flow in dissection models to better guide interventions to prevent aneurysm formation and false lumen flow. Silicone models of aortic dissection with mobile intimal flap were fabricated based on patient images and installed in a flow loop with pulsatile flow. Flow fields were acquired via 4-dimensional flow MRI, allowing for quantification and visualization of relevant fluid mechanics. Pulsatile vortices and jet-like structures were observed at fenestrations immediately past the proximal entry tear. False lumen flow reversal was significantly reduced with the addition of fenestrations, from 19.2 ± 3.3% in two-tear dissections to 4.67 ± 1.5% and 4.87 ± 1.7% with each subsequent fenestration. In contrast, increasing pressure did not cause appreciable differences in flow rates, flow reversal, and vortex formation. Increasing the number of intermediate tears decreased flow reversal as compared to two-tear dissection, which may prevent false lumen thrombosis, promoting persistent false lumen flow. Vortices were noted to result from transluminal fluid motion at distal tear sites, which may lead to degeneration of the opposing wall. Increasing pressure did not affect measured flow patterns, but may contribute to stress concentrations in the aortic wall. The functional and anatomic assessment of disease with 4D MRI may aid in stratifying patient risk in this population.

Open surgical repair of post-dissection thoraco-abdominal aortic aneurysms: early and late outcomes of a single-centre study involving over 200 patients

OBJECTIVES

Chronic, post-dissection thoraco-abdominal aortic aneurysms (TAAAs) are increasingly being treated by (hybrid) endovascular means. Although it is less invasive, thoracic endovascular aortic repair is technically complex with the risk of incomplete aneurysm exclusion, necessitating frequent reinterventions with potentially reduced long-term outcomes. The aim of this study was to evaluate contemporary early and late outcomes after open surgical repair of post-dissection TAAA.

METHODS

At our centre, 633 patients underwent open repair for TAAA over a 20-year period (1994-2015), including 217 (34%) patients for post-dissection TAAA, who were included in this analysis. Circulatory support was obtained by either left heart bypass (173 patients, 79.7%), deep hypothermic circulatory arrest (41 patients, 18.9%) or simple aortic cross-clamping in 3 patients. We analysed all relevant perioperative and intraoperative variables with respect to adverse outcomes. Additionally, long-term survival and the need for aortic reinterventions were studied.

RESULTS

The mean age was 60.2 ± 11.9 years (men 68.2%). We identified 66 Type I (30.4%), 113 Type II (52.1%), 25 Type III (11.5%), 10 Type IV (4.6%) and 3 Type V (1.4%) TAAAs. Early mortality and spinal cord deficit were 5.9% and 5.5%, respectively. Follow-up was 100% complete (mean 6.0 ± 5.8 years), with long-term survival of 71.4% at 10 years, and freedom from death and reoperation was 68.2% at 10 years.

CONCLUSIONS

Although it is more invasive than current endovascular approaches for post-dissection TAAA, open surgical repair can be performed safely with acceptable rates of morbidity and mortality when it is done in a specialized aortic centre. Long-term survival and freedom from aortic reintervention are excellent and should also be taken into account when evaluating less invasive alternatives.

How should we treat uncomplicated subacute type B aortic dissection in octogenarians?

BACKGROUND

Preemptive thoracic endovascular aortic repair (TEVAR) is an advanced treatment that has possibility to improve late outcomes in patients with subacute type B aortic dissection. However, it may not be the treatment of choice for elderly patients with uncomplicated subacute type B aortic dissection because of their inherent frailty and increased risk of periprocedural complications.

METHODS

Data were collected between July 2004 and October 2017 in Yamagata university hospital and between February 2016 and May 2018 in Nihonkai General hospital. A total of 152 medically treated subacute type B aortic dissection patients were enrolled in this study. Patients were divided into two groups: age 80 year and older group (Group O, n = 33, 22%) and a group < 80 years of age (Group U, n = 119, 78%).

RESULTS

During follow-up, the incidence of adverse events was 27% (n = 9) in Group O and 37% (n = 44) in Group U (P = 0.409). The incidence of aortic rupture was 3% (n = 1), and the incidence of acute type A dissection was 3% (n = 1) in Group O. In Group O, only one patient (3%) died of aorto-bronchial fistula. The Group O patients had less surgical intervention (3 patients [9%] in Group O and 30 patients [25%] in Group U, P = 0.047), but aortic related death did not differ between the two groups. The 1-, 2-, and 5-year freedom from aorta-related death rates of Group O were 97, 97, and 97%, respectively, compared with 99, 94, and 91%, respectively, in Group U (P = 0.880).

CONCLUSIONS

Patients aged 80 years and older who underwent medical treatment for acute and subacute type B dissection had excellent outcomes in chronic phase. The elderly patients had less surgical intervention, but aortic related death did not differ from younger patients.

Staged coil embolization after thoracic endovascular stent grafting for aneurysmal chronic type B aortic dissection: A case report

We herein describe a 38-year-old woman with Marfan syndrome and chronic type A aortic dissection. Computed tomography showed that the sinus of Valsalva and thoracoabdominal aorta had a diameter of 62 and 55 mm, respectively. After 7 months of a Bentall operation and total arch replacement with the elephant trunk technique, we performed thoracic endovascular aortic repair for an aneurysm of the descending aorta, but we preserved the retrograde flow into the false lumen because it supplied vessels perfusing the spinal cord. Computed tomography angiography 14 months after thoracic endovascular aortic repair showed that the thoracic aortic diameter had increased to 68 mm. We then performed partial (proximal only) coil embolization of the false lumen. After 6 months, the thoracic aortic diameter had decreased to 60 mm and the spinal cord remained perfused via the distal false lumen. Staged coil embolization after thoracic endovascular aortic repair for aneurysmal chronic type B aortic dissection is feasible and can be beneficial.

Thoracic Endovascular Aortic Repair for Acute Aortic Dissection

Thoracic endovascular aortic repair (TEVAR) for thoracic aortic disease constitutes a paradigm shift in the treatment strategy of aortic dissection, as well as thoracic aortic aneurysms. Conventionally, most patients with Stanford type B acute aortic dissection are treated using conservative medical treatment during the acute phase. However, in patients with complicated type B aortic dissection who present with life-threatening complications, TEVAR has been introduced as a novel and less-invasive alternative and has shown better early results than those observed with conventional therapy. Recently, TEVAR was reported to be effective in not only promoting thrombosis of the false lumen but also in preventing aortic enlargement observed at long-term follow-up. TEVAR has been established as first-line therapy for complicated type B aortic dissection. In contrast, a considerable number of patients who received acute phase medical treatment required surgical intervention for chronic dissecting aortic aneurysms. With the increasing popularity of TEVAR for the treatment of complicated type B aortic dissection, prophylactic and pre-emptive TEVAR has been considered in patients with uncomplicated type B aortic dissection. However, supportive evidence for this strategy is limited, and reassessment is mandatory because it is continuously evolving. Although acute type A aortic dissection is a life-threatening condition, the results of open surgery continue to improve in the modern surgical era. Open surgical treatment is well established and recognized as a gold standard even in the endovascular era. Presently, the application of TEVAR for ascending aortic dissection has undergone a change, and TEVAR is considered a viable rescue option for patients with type A aortic dissection who are not eligible for open surgical repair. However, TEVAR for the descending aorta is well-established treatment for retrograde type A dissection. Several conceptual and technical issues remain unresolved, and technological advances would lead to the development of innovative disease-specific devices and solutions in the future for endovascular treatment of acute aortic dissection. (This is a translation of Jpn J Vasc Surg 2018; 27: 337–345.)

Analysis of Risk Factors for Aortic Enlargement in Patients with Chronic Type B Aortic Dissection

Objectives: Uncomplicated type B aortic dissection is generally treated with medical management including antihypertensive therapy. The purpose of this study is to investigate risk factors associated with the aortic enlargement in medically treated patients. Methods: Between July 2004 and April 2016, 127 consecutive patients with acute type B aortic dissection were treated in our institution. Of these, 104 patients diagnosed with uncomplicated type B dissection were managed medically as an initial treatment. According to the diameter of the dissected aorta, these patients were retrospectively placed into 2 groups: 1) enlargement group (group E: n=36); and 2) unchanged group (group U: n=68). Results: There was statistically significant difference regarding the initial diameter of the dissected aorta (group E: 42±7 mm, group U: 36±7 mm) (p<0.01). As regards the aneurysm growth rate, a significant difference between both groups was noted (group E: 10±32 mm/half-year, group U -3±19 mm/half-year) (p<0.05). In all 104 patients, 42 patients (40.4%) had patent false lumen with the average number of 1.5 intimal tears. Multivariate analysis showed the relationship for aortic enlargement were patent false lumen (p<0.05, 95%CI 0.407-0.935) and initial aortic diameter (p<0.01, 95%CI 1.076-1.158). Aortic event free survival (1/5/10 years) was 100/86/77% in group E and 92/79/79% in group U, respectively no differences between two groups (p=0.747). Conclusions: The medically managed patients with uncomplicated chronic type B dissection showed excellent survival rate during long-term follow-up. The results of surgical or endovascular treatment in patients underwent initial medical therapy were also satisfactory. The patent false lumen and aortic diameter at the onset may impact on aortic enlargement. Considering our results, the feasibility of elective endovascular repairs in stable dissection remains controversial even in the endovascular era. (This is a translation of Jpn J Vasc Surg 2018; 27: 55-60.).

Fate of uncomplicated acute type B aortic dissection and impact of concurrent aortic dilatation on remote aortic events

OBJECTIVE

This study aimed to describe the reliable prognostic factors of mortality and subsequent aortic events during the follow-up of uncomplicated type B acute aortic dissection.

METHODS

From January 2004 to December 2014, 255 patients with uncomplicated type B acute aortic dissection were admitted to our hospital. Cox proportional hazards analysis was performed to identify risk factors for all-cause mortality, aorta-related mortality, and aortic events.

RESULTS

In-hospital mortality was observed in 7 patients (2.7%). The rates of 5-year freedom from all-cause mortality, aorta-related mortality, and aortic events were 79.4% ± 2.9%, 93.3% ± 2.0%, and 71.7% ± 3.4%, respectively. The rate of 5-year freedom from aortic events was significantly lower among those with a patent false lumen (P = .006). Age and descending aorta diameter were independent risk factors of all-cause and aorta-related mortality (hazard ratio [HR], 1.08 and 1.13; 95% confidence interval [CI], 1.04-1.10 and 1.03-1.24; P = .0001 and .007, respectively). Independent risk factors for aortic events were descending aorta diameter, false lumen thickness, and dilatation of abdominal aorta (HR, 1.06; 95% CI, 1.02-1.12; P = .006; HR, 1.07; 95% CI, 1.04-1.11; P = .00002; HR, 2.01; CI, 1.20-3.38; P = .008).

CONCLUSIONS

In uncomplicated type B acute aortic dissection, the age and dilatation of the thoracic aorta were associated with a higher risk of death, whereas false lumen thickness and concurrent abdominal aortic dilatation augment the risk for aortic events.

Current evidence in predictors of aortic growth and events in acute type B aortic dissection

OBJECTIVES

Acute type B aortic dissection can have a stable course or evolve into aneurysm and subsequent adverse events. The aim of this systematic review was to analyze the morphologic predictors of an adverse course to establish their validity based on consistency of results.

METHODS

Fifty-one studies were included in this review, reporting on aortic size, false lumen (FL) size, primary entry tear (ET) size and location, status of FL thrombosis, number of ETs, branch vessels involvement, and FL longitudinal extent.

RESULTS

Some predictors showed good consistency, whereas others did not. Aortic size was the most investigated predictor. A larger diameter at presentation predicted worse outcomes, with few exceptions. Both FL size and size relative to true lumen size also predicted an adverse course, although a standardized measurement method was not used. Regarding primary ET size and location, evidence was sparse and somewhat conflicting. Although FL complete thrombosis was consistently associated with a more benign course, the role of partial thrombosis remained unclear and the concept of FL saccular formation might account for the inconsistency, but further evidence is needed. A higher number of re-entry tears was considered to be protective against false channel expansion, but results need to be confirmed. The predictive role of branch vessels involvement and FL longitudinal extent remain controversial.

CONCLUSIONS

Among several predictors of aortic growth and events in acute type B aortic dissection, controversial and even conflicting results have been described. Consistent evidence has been demonstrated only for two predictors: aortic size at presentation is associated with adverse events and total FL thrombosis has a protective role.

The prognostic impact of distal anastomotic new entry after acute type I aortic dissection repair

OBJECTIVES

Distal anastomotic new entry (DANE) is considered to be one of the causes of patent false lumen (PFL) after acute type I aortic dissection repair. However, there have been few articles with regard to this important issue. We assessed the influence of PFL caused by DANE on long-term outcomes.

METHODS

One hundred twenty-two patients underwent emergency surgery for acute type I aortic dissection (2007-12). The in-hospital mortality was 8% (10 patients). Among the survivors, 93 patients (mean age 67 years) underwent enhanced computed tomography within 2 weeks after the operation. These patients were divided into 3 groups according to the status of the residual FL: those with a PFL with DANE (n = 19) or without DANE (n = 27) and those with a thrombosed FL (n = 47). Changes in descending aortic diameter were analysed between early and last follow-up images.

RESULTS

Aortic growth rate in the PFL with DANE group was greater than that of the other 2 groups (P < 0.05). The PFL with DANE group demonstrated a lower rate of freedom from dissection-related event of distal aorta (66% at 5 years) and enlargement of distal aortic lesions (62% at 5 years). There were no significant differences in late survival among the groups. PFL with DANE was one of the significant risk factors for distal aortic events.

CONCLUSIONS

PFL caused by DANE after acute type I aortic dissection repair showed greater aortic growth rate of the descending aorta and was one of the significant risk factors for distal aortic events.