Aneurysmal degeneration of the thoracoabdominal aorta after medical management of type B aortic dissections

Questionable Long-Term Results of the Extended Provisional Extension to Induce Complete Attachment (E-PETTICOAT) Technique in the Management of Chronic Type B Aortic Dissection

BACKGROUND

Published interim results of the extended provisional extension to induce complete attachment (e-PETTICOAT) technique suggested favorable remodeling in chronic type B Aortic Dissection (cTBAD). This report presents long-term results of the e-PETTICOAT technique for the management of cTBAD (without aneurysmal dilatation).

METHODS

Patients with cTBAD below the 55 mm aortic size were eligible for the management using the e-PETTICOAT technique. Follow-up was conducted at 1, 2 and 5 years based on the computed tomography angiogram. All the presurgery risk factors (entry >1 cm, inner curve entry, fusiform index >0.65, false lumen > 22 mm, aortic size >40 mm, recurrent pain or hypertension, and Stanford Dissection Risk Calculation) and postsurgery complications were examined in the study.

RESULTS

A total of 20 patients underwent the e-PETTICOAT surgery. The survival rate at 1, 2, and 5 years was 75%, 70%, and 64%, respectively, and the percentage of patients without any reinterventions was 100%, 93%, and 18%. Aortic degeneration was recognized in 30%, 55%, and 85% of the patients. Only 3 of the 20 patients were alive and without any reintervention after 5 years. The receiver operating curve analysis does not indicate any factor that would predict the remodeling result in the long-term follow-up.

CONCLUSIONS

The use of e-PETTICOAT technique in cTBAD might not have a beneficial influence on the long-term results.

Initial Thoracic Endovascular Aortic Repair vs Medical Therapy for Acute Uncomplicated Type B Aortic Dissection

Importance

Thoracic endovascular aortic repair (TEVAR) has increasingly been used for uncomplicated type B aortic dissection (uTBAD) despite limited supporting data.

Objective

To assess whether initial TEVAR following uTBAD is associated with reduced mortality or morbidity compared with medical therapy alone.

Design, Setting, and Participants

This cohort study included Centers for Medicare & Medicaid Services inpatient claims data for adults aged 65 years or older with index admissions for acute uTBAD from January 1, 2011, to December 31, 2018, with follow-up available through December 31, 2019.

Exposures

Initial TEVAR was defined as TEVAR within 30 days of admission for acute uTBAD.

Main Outcomes and Measures

Outcomes included all-cause mortality, cardiovascular hospitalizations, aorta-related and repeated aorta-related hospitalizations, and aortic interventions associated with initial TEVAR vs medical therapy. Propensity score inverse probability weighting was used.

Results

Of 7105 patients with eligible index admissions for acute uTBAD, 1140 (16.0%) underwent initial TEVAR (623 [54.6%] female; median age, 74 years [IQR, 68-80 years]) and 5965 (84.0%) did not undergo TEVAR (3344 [56.1%] female; median age, 76 years [IQR, 69-83 years]). Receipt of TEVAR was associated with region (vs South; Midwest: adjusted odds ratio [aOR], 0.66 [95% CI, 0.53-0.81]; P < .001; Northeast: aOR, 0.63 [95% CI, 0.50-0.79]; P < .001), Medicaid dual eligibility (aOR, 0.76; 95% CI, 0.63-0.91; P = .003), hypertension (aOR, 1.26; 95% CI, 1.03-1.54; P = .03), peripheral vascular disease (aOR, 1.24; 95% CI, 1.02-1.49; P = .03), and year of admission (2012, 2013, 2014, and 2015 were associated with greater odds of TEVAR compared with 2011). After inverse probability weighting, mortality was similar for the 2 strategies up to 5 years (hazard ratio [HR], 0.95; 95% CI, 0.85-1.06), as were aorta-related hospitalizations (HR, 1.12; 95% CI, 0.99-1.27), aortic interventions (HR, 1.01; 95% CI, 0.84-1.20), and cardiovascular hospitalizations (HR, 1.05; 95% CI, 0.93-1.20). In a sensitivity analysis that included deaths within the first 30 days, initial TEVAR was associated with lower mortality over a period of 1 year (adjusted HR [aHR], 0.86; 95% CI, 0.75-0.99; P = .03), 2 years (aHR, 0.85; 95% CI, 0.75-0.96; P = .008), and 5 years (aHR, 0.87; 95% CI, 0.80-0.96; P = .004).

Conclusions and Relevance

In this study, 16.0% of patients underwent initial TEVAR within 30 days of uTBAD, and receipt of initial TEVAR was associated with hypertension, peripheral vascular disease, region, Medicaid dual eligibility, and year of admission. Initial TEVAR was not associated with improved mortality or reduced hospitalizations or aortic interventions over a period of 5 years, but in a sensitivity analysis that included deaths within the first 30 days, initial TEVAR was associated with lower mortality. These findings, along with cost-effectiveness and quality of life, should be assessed in a prospective trial in the US population.

Procedure and Aortic Remodeling Effects of Entry Closure with Stentgraft for Type B Aortic Dissection: Comparison between the Patients with Narrow True Lumen and Those with Aneurysmal Dilated False Lumen

Objectives: Appropriateness of device selection, procedure protocol and aortic remodeling effects of entry closure (TEVAR) with stent-graft (SG) for patent false lumen type B aortic dissection (TBAD) were compared between the patients with narrow true lumen (narrow group) and those with aneurysmal dilated false lumen (aneurysmal group).

Methods: Twenty-six patients with narrow true lumen (narrow group) and 20 patients with aneurysmal false lumen (aneurysmal group) were included in this study. In narrow group, straight SG was implanted from Zone 3 regardless the distance between the left subclavian artery and entry. In aneurysmal group, straight or taped SG was implanted with proximal landing zone length 20 mm or more. Thoracic aortic anatomy was evaluated by CT and aortic remodeling was defined as true lumen diameter ≥50% of the aortic diameter and occlusion of false lumen. Aorta related death, retrograde type A aortic dissection (RTAD), stentgraft induced new entry (SINE) and aortic maximum diameter enlargement 5 mm or more (aortic expansion) were included in the aortic event.

Results: There was no procedure related complication in narrow group and 1 patient died due to aortic rupture in aneurysmal group, Type Ia endoleak by enhanced CT 7 days after TEVAR was detected in one patient in each group. Achievement of aortic remodeling was significantly better in narrow group. Aortic event occurred in only one patient in narrow group, in whom aortic expansion was observed. In aneurysmal group, aortic event occurred 12 patients (60%) and 2 RTAD, 5 SINE, and 8 aorta expansion were observed. Aortic event free rate was significantly better in narrow group.

Conclusion: TEVAR procedure for the TBAD patients with narrow true lumen seemed to be appropriate, however, different TEVAR procedure or additional procedures would be required for those with aneurysmal dilated false lumen to obtain favorable outcomes. (This is secondary publication from Jpn J Vasc Surg 2021; 30: 347–357.)

Aortic Visceral Segment Instability is evident following Thoracic Endovascular Aortic Repair for Acute and Subacute Type B Aortic Dissection

BACKGROUND

Anatomic remodeling within the thoracic aorta following thoracic endovascular aortic repair (TEVAR) for type B aortic dissections (TBAD) has been well documented, but less is known about the response of the untreated visceral aorta. This study aims to investigate visceral aortic behavior following TEVAR for acute or subacute TBAD and identify associations with clinical outcomes.

METHODS

A multi-center retrospective review was performed of all imaging for all patients treated with TEVAR for acute (0-14 days) and subacute (14-90 days) non-traumatic TBAD between 2006-2020. Cohort was inclusive of uncomplicated, high-risk, and complicated (defined per SVS reporting guidelines) dissections. Centerline aortic measurements of the true and false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone (zones defined by SVS reporting guidelines). Diameter changes over time were evaluated using repeated measures mixed effects linear growth modeling. Visceral segment instability (VSI) was defined as any growth in TAD ≥ 5mm within aortic zones 5 through 9.

RESULTS

A total of 82 patients were identified. Median length of imaging follow-up was 2.1 years (IQR 3.9 years), with 15% of the cohort having follow-up longer than 5 years. VSI was present in 55% of the cohort, with an average maximal increase in TAD of 10.4±6.3 mm over a median follow-up of 2.1 years (IQR 3.9 years). Roughly a third of the cohort experienced rapid VSI (growth ≥5mm in first year), and 4.8% of the cohort developed a large para-visceral aneurysm aortic (TAD≥5cm) secondary to VSI. Linear growth modeling identified significant predictable growth in TAD across all visceral zones. Zones 7 had the highest rate of TAD dilation, with a fixed effect estimated rate of 1.3 mm per year (95%-CI 0.23-2.1, p=0.022). The preoperative factor most strongly associated with VSI was ≥6 cumulative number of zones dissected (OR 6.4, 95% OR 1.07-8.6, p=0.041). Odds for aortic reintervention were significantly increased in cases where VSI led to development of a para-visceral aortic aneurysm ≥5cm development (OR 3.7, 95%-CI 1.1-13, p=0.038).

CONCLUSION

VSI was identified in the majority of patients treated with TEVAR for management of acute and subacute TBAD. Preoperative anatomic features such as extent of dissection, rather than procedural details of graft coverage, may play a more significant role in VSI occurrence. Importantly, significant TAD growth occurred in all visceral segments. These results highlight the importance of lifelong surveillance following TEVAR, and identify a subset of patients that may be at increased risk for re-intervention.

Predictors of Long-Term Aortic Growth and Disease Progression in Patients with Aortic Dissection, Intramural Hematoma, and Penetrating Aortic Ulcer

BACKGROUND

We aimed to identify predictors of long-term aortic diameter change and disease progression in a population cohort of patients with newly diagnosed aortic dissection (AD), intramural hematoma (IMH), or penetrating aortic ulcer (PAU).

METHODS

We used the Rochester Epidemiology Project record linkage system to identify all Olmsted County, MN-USA, residents diagnosed with AD, IMH, and PAU (1995-2015). The endpoints were aortic diameter change, freedom from clinical disease progression (any related intervention, aortic aneurysm, new aortic syndrome, rupture or death) and disease resolution (complete spontaneous radiological disappear). Linear regression was used to assess aortic growth rate; predictors of disease progression were identified with Cox proportional hazards.

RESULTS

Of 133 incident cases, 46 ADs, 12 IMHs, and 28 PAUs with sufficient imaging data were included. Overall median follow-up was 8.1 years. Aortic diameter increase occurred in 40 ADs (87%, median 1.0 mm/year), 5 IMHs (42%, median 0.2 mm/year) and 14 PAUs (50%, median 0.4 mm/year). Symptomatic presentation (P = 0.045), connective tissue disorders (P = 0.005), and initial aortic diameter >42 mm (P = 0.013) were associated with AD growth rate. PAU depth >9 mm (P = 0.047) and female sex (P = 0.013) were associated with aortic growth rate in PAUs and IMHs. At 10 years, freedom from disease progression was 22% (95% CI 12-41) for ADs, 44% (95% CI 22-92) for IMHs, and 46% (95% CI 27-78) for PAUs. DeBakey I/IIIB AD (HR 3.09; P = 0.038), initial IMH aortic diameter (HR 1.4; P = 0.037) and PAU depth >10 mm (HR 3.92; P = 0.018) were associated with disease progression. No AD spontaneously resolved; resolution rate at 10 years was 22% (95% CI 0-45) for IMHs and 11% (95% CI 0-23) for PAUs.

CONCLUSIONS

Aortic growth and clinical disease progression are observed in most patients with aortic syndromes, while spontaneous resolution is uncommon. Predictors of aortic growth and disease progression may be used to tailor appropriate follow-up and eventual early intervention.

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.

Anatomy, Pathology, and Classification of Aortic Dissection

The incremental understanding of the anatomy and pathophysiology of aortic dissection over the past 250 years has predicated the modern endovascular treatments in use today. Since the early descriptions of aortic dissection, our knowledge of the predisposing factors and hemodynamic disturbances that lead to aortic dissection and overlapping syndromes, including intramural hematoma and penetrating atherosclerotic ulcer, has been fine-tuned, aided by more advanced ultrastructural histopathologic analysis and modern cross-sectional imaging techniques. However, several controversies and ambiguities of the pathophysiology and natural history of aortic dissection persist, leading to ongoing challenges in prevention, clinical diagnosis and treatment. In this review, we aim to describe the anatomy, pathology, and classification of aortic dissection and introduce the pathophysiologic basis for endovascular therapies.

Predictors of adverse events in uncomplicated type B aortic dissection: a systematic review with meta-analysis

INTRODUCTION

Thoracic Endovascular Aortic Repair (TEVAR) has been selectively used for uncomplicated acute type B Aortic Dissection (TBAD); however, not all cases will benefit from TEVAR. A search for high risk clinical and radiographic predictors for complications is ongoing. This systematic review and meta-analysis aimed to identify predictors of major adverse events during follow-up of uncomplicated TBAD, in order to identify who might benefit from elective TEVAR.

EVIDENCE ACQUISITION

A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) statement.

EVIDENCE SYNTHESIS

16 studies were included in a qualitative synthesis and 10 in the meta-analysis. Several risk factors associated to major adverse events have been described, including (1) aortic diameter ≥40 mm, (2) greater false lumen diameter (>22mm), (3) patent false lumen, (4) primary entry tear > 10mm, and (5) greater number of false lumen vessels origin. Quantitative synthesis identified an aortic diameter ≥40 mm significantly associated with major adverse events (HR=3.56; p<0.00001). Reporting of false lumen status, aortic diameters and growth, and demographic data was not always congruent with the most recent recommendations by Society for Vascular Surgery and Society of Thoracic Surgeons, published in 2020.

CONCLUSIONS

Acute and subacute patients with uncomplicated TBAD presenting with an aortic diameter ≥ 40 mm and solely treated with BMT have an increased hazard of developing major adverse events (HR), making them potential candidates for TEVAR. Remaining risk factors analysed have weaker evidence.

Elevated preoperative neutrophil-to-lymphocyte ratio predicts early adverse outcomes in uncomplicated type B aortic dissection undergoing TEVAR

BACKGROUND

Thoracic aortic endovascular repair (TEVAR) of uncomplicated type B aortic dissection (uTBAD) has favorable long-term outcomes but higher early adverse events compared with the optimal medical treatment. Recently, clinical evidence concerning vascular surgery indicates that elevated preoperative systemic inflammatory response predicts adverse clinical events. The aim of our study was to evaluate the relationship between preoperative neutrophil-to-lymphocyte ratio (NLR) and early outcomes of uTBAD patients undergoing TEVAR.

RESULTS

216 patients diagnosed with uTBAD were included in this retrospective study between January 2015 and December 2018. The median (IQR) follow-up period was 21 (15-33) months. An early adverse event was defined as occurring within 2 years after the procedure. Median patient age was 60 (IQR, 48-68) years and 78.7 % were male. Early adverse events occurred in 24 patients (11.1 %). In the multivariable analysis, preoperative NLR (HR per SD, 1.98; 95 % CI, 1.14-3.44; P = 0.015) was associated with 2-year adverse events.

CONCLUSIONS

NLR is an independent predictive factor of early adverse events in uTBAD patients undergoing TEVAR.

Endograft exclusion of the false lumen restores local hemodynamics in a model of type B aortic dissection

OBJECTIVE

Endovascular intervention in uncomplicated type B dissection has not been shown conclusively to confer benefit on patients. The hemodynamic effect of primary entry tear coverage is not known. Endovascular stent grafts were deployed in a model of aortic dissection with multiple fenestrations to study these effects. It is hypothesized that endograft deployment will lead to restoration of parabolic true lumen flow as well as elimination of false lumen flow and transluminal jets and vortices locally while maintaining distal false lumen canalization.

METHODS

Thoracic stent grafts were placed in silicone models of aortic dissection with a compliant and mobile intimal flap and installed in a flow loop. Pulsatile fluid flow was established with a custom positive displacement pump, and the models were imaged by four-dimensional flow magnetic resonance imaging. Full flow fields were acquired in the models, and velocities were extracted to calculate flow rates, reverse flow indices, and oscillatory shear index, the last two of which are measures of stagnant and disturbed flows.

RESULTS

Complete obliteration of the false lumen was achieved in grafted aorta, with normal parabolic flow profiles in the true lumen (maximal velocity, 30.4 ± 8.4 cm/s). A blind false lumen pouch was created distal to this with low-velocity (5.8 ± 2.7 cm/s) and highly reversed (27.9% ± 13.9% reverse flow index) flows. In distal free false lumen segments, flows were comparable to ungrafted conditions with maximal velocities on the order of 7.0 ± 2.1 cm/s. Visualization studies revealed forward flow in these regions with left-handed vortices from true to false lumen. Shear calculations in free false lumen regions demonstrated reduced oscillatory shear index.

CONCLUSIONS

Per the initial hypothesis, endovascular grafting improved true lumen hemodynamics in the grafted region. Just distally, a prothrombotic flow regimen was noted in the false lumen, yet free false lumen distal to this remained canalized. Clinically, this suggests a need for advancing endovascular intervention beyond sole entry tear coverage to prevent further false lumen canalization through uncovered fenestrations.

Remodeling, Reintervention, and Survival After Endovascular Repair of Chronic Type B Dissection

BACKGROUND

The efficacy of thoracic endovascular aortic repair (TEVAR) of chronic type B aortic dissection (cTBAD) is controversial. Only limited evidence describes temporal anatomic changes after TEVAR for cTBAD and their relationship to outcomes. We sought to investigate early aortic remodeling events after TEVAR for cTBAD with thoracic aneurysm and determine the association with reintervention and survival.

METHODS

Records from 95 cTBAD patients undergoing TEVAR from 2005 to 2017 were reviewed. Using 3-dimensional centerline analysis, anatomic phenotyping of the thoracoabdominal aorta was performed. Reverse aortic remodeling (RAR) was defined by a ≥5-mm reduction in maximal thoracic aortic diameter. Kaplan-Meier analysis estimated freedom from reintervention and survival.

RESULTS

Visceral segment dissection involvement was present in 89% of patients (n = 85), and the mean preoperative thoracic diameter was 63 mm (SD, 10). Complete thoracic false lumen thrombosis occurred in 71% of patients (n = 67), whereas abdominal false lumen thrombosis was documented in 60% (n = 57) by 6 months. RAR occurred in 41%. Aortic reintervention rate was 39% (n = 37). The 1- and 3-year freedom from reintervention was significantly higher in subjects experiencing early RAR (log-rank P = .02), but reintervention did not impact overall survival (log-rank P = .9). Similarly, overall survival was similar between patients with or without RAR (log-rank P = .4).

CONCLUSIONS

Early RAR is associated with decreased rates of reintervention; however, overall survival is not impacted by these changes. TEVAR for cTBAD results in a high rate of reintervention, which mandates vigilant surveillance protocols.

Predictive Factors of Operative Need in Medically Managed Type B Aortic Dissections

BACKGROUND

Aneurysmal degeneration of medically managed type B aortic dissection (TBAD) can be a life-threatening condition. Preventive thoracic endovascular aorta repair (TEVAR) in patients at risk could potentially be beneficial. The aim of this study was to examine the predictors for late aneurysmal dilatation after TBAD.

METHODS

A retrospective study was conducted on 82 patients with medically managed acute TBAD for a minimum of 14 days. Relevant demographic, biochemical, and radiographic variables at presentation were studied. The aortic dissection risk calculator tool developed by Sailer et al., predicting the risk of adverse events after aortic dissection based on demographic and radiographic variables at presentation, was tested retrospectively.

RESULTS

With a median follow-up of 36 months (range 13-68), 25 (30.5%) patients underwent surgery (92% TEVAR). A larger initial aortic and false lumen diameter as well as a greater distal extension of the dissection was associated with higher need for surgery (respectively, P = 0.003, P = 0.004, and P = 0.001). We observed higher growth rates of maximum aortic diameter in patients with a greater distal extension of the dissection, larger false lumen diameters and false lumen outflow, and entry tears located at the inner aortic arch (respectively, P = 0.001, P = 0.005, P = 0.001 and P = 0.014). No significant correlations could be found for the risks provided by the calculator tool.

CONCLUSIONS

The initial maximum aortic diameter of TBAD is a key predictor for aortic growth. Furthermore, the distal extension of the dissection also seems to play an important role in late aneurysmal degeneration. However, we were not able to confirm the added value of the risk calculator tool in our study group.

One-Year Single-Center Results of the Multilayer Flow Modulator Stents for the Treatment of Type B Aortic Dissection

Purpose

To report a single-center series of patients with type B aortic dissection treated with the Multilayer Flow Modulator (MFM).

Materials and Methods

Over a 36-month period, 23 patients (median age 53 years; 20 men) with complicated type B aortic dissections (2 acute, 5 subacute, and 16 chronic) were treated with the MFM. Primary endpoints of rupture or dissection-related death, overall mortality, and reintervention were evaluated using the Kaplan-Meier method; estimates for freedom from the endpoints are reported with the 95% confidence interval (CI). Secondary outcomes included technical success, adverse events, and aortic remodeling. Clinical and imaging data were collected preoperatively, directly postoperatively, and annually to 36 months for analysis using computational fluid dynamics (CFD).

Results

Initial technical success was 91.3%. The estimates of the endpoints at 12 months were 100% for freedom from rupture or aortic-related death, 95.7% for freedom from overall mortality, and 91.3% for freedom from reintervention. No device-related neurological or systemic complications occurred, and no additional reinterventions were needed during follow-up. A total of 144 branches overstented by the MFM remained patent. Morphologic analysis of the aortic dissection showed progressive true lumen volume increase (75.9%, p<0.001) with concomitant false lumen volume decrease (42.8%, p<0.001); the CFD analyses showed increased laminar flow.

Conclusion

In the current series, the MFM provided a safe and feasible treatment option for complicated acute, subacute, and chronic type B aortic dissections, with high technical success, low mortality, and active aortic remodeling. Further studies should elucidate the long-term safety of the MFM and its effectiveness in a larger patient cohort.

Gaussian Surface Curvature Mapping Indicating High Risk Type B Thoracic Aortic Dissections

BACKGROUND

Identifying fragile aortas that are more likely to lead to adverse clinical outcomes would provide surgeons with a better sense of how to balance the risks of surgical versus medical management in patients with type B dissections. We examine the progression of a type B dissection into a type A dissection in a patient and analyze changes in the Gaussian surface curvature distribution, as well as the response of the stress distribution at the lesser curve in response to pressurization. We hypothesize that examining the Gaussian curvature will provide us with a link between aortic surface geometry and the stress distribution, which is crucial to understanding the process driving aortic dissection.

METHODS

Computed tomography scans of a patient before and after the type A dissection are obtained. These are segmented in Simpleware ScanIP. Centerline curvatures are calculated on segmented models in ScanIP. Models are then pressurized in the finite element analysis software Abaqus. The Gaussian curvature is calculated by exporting segmentations into the computational program Matlab and applying a modified previously published algorithm.

RESULTS

The centerlines generated in ScanIP fail to capture the change in the acuity of the lesser curve before and after the type A dissection. Instead, Gaussian curvature analysis shows that the curvature distribution before the type A dissection is much wider compared with the distribution after the type A dissection. In addition, analyzing the stress distribution in response to pressurization reveals that before the type A dissection there is a large divergence in the principal stress vectors at the lesser curve but this transitions to a more uniform hoop stress after the type A dissection.

CONCLUSIONS

Our analysis demonstrates that Gaussian surface curvature analysis captures changes in aortic geometry that are otherwise silent in centerline curvature analysis. Here, we show that as the aorta develops a type A dissection it is able to more smoothly handle the hoop stress at the lesser curve compared with the stress focusing seen in the before type A geometry. We propose that the geometric focusing before type A creates a higher energy stress state, which is relaxed on retrograde dissection. Thus, Gaussian curvature analysis may provide a window to capture underlying geometric instability in type B dissections.

Cause-specific mortality of type B aortic dissection and assessment of competing risks of mortality

OBJECTIVE

Natural history studies of type B aortic dissection (TBAD) commonly report all-cause mortality. Our aim was to determine cause-specific mortality in TBAD and to evaluate the clinical characteristics associated with aorta-related and nonaorta-related mortality.

METHODS

Clinical and administrative records were reviewed for patients with acute TBAD between 1995 and 2017. Demographics, comorbidities, presentation, and initial imaging findings were abstracted. Cause of death was ascertained through a multimodality approach using electronic health records, obituaries, social media, Social Security Death Index, and state mortality records. Causes of death were classified as aorta related, nonaorta related, or unknown. A Fine-Gray multivariate competing risk regression model for subdistribution hazard ratio was employed to analyze the association of clinical characteristics with aorta-related and nonaorta-related mortality.

RESULTS

A total of 275 individuals met inclusion criteria (61.1 ± 13.7 years, 70.9% male, 68% white). Mean survival after discharge was 6.3 ± 4.7 years. Completeness of follow-up Clark C index was 0.87. All-cause mortality was 50.2% (n = 138; mean age, 70.1 ± 14.6 years) including an in-hospital mortality of 8.4%. Cause-specific mortality was aorta related, nonaorta related, and unknown in 51%, 43%, and 6%, respectively. Compared with patients with nonaorta-related mortality, patients with aorta-related mortality were younger at acute TBAD (69.5 ± 11.2 years vs 61.6 ± 15.5 years; P = .001), underwent more descending thoracic aortic repairs (19.4% vs 45.8%; P = .002), and had a shorter survival duration (5.7 ± 3.9 vs 3.4 ± 4.5 years; P = .002). There was clear variation in cause of death by each decade of life, with higher aorta-related mortality among those younger than 50 years and older than 70 years and a stepwise increase in nonaorta-related mortality with each increasing decade (P < .001). All-cause mortality at 1 year, 3 years, and 10 years was 15%, 24%, and 57%, respectively. After accounting for competing risks, the cumulative incidence of aorta-related mortality at 1 year, 3 years, and 10 years was 8.9%, 16.5%, and 27.2%, respectively, and that of nonaorta-related mortality was 2.7%, 7.2%, and 29%, respectively. A maximum descending thoracic aortic diameter >4 cm was associated with an increase in hazard of aorta-related mortality by 84% (subdistribution hazard ratio, 1.84; 95% confidence interval, 1.03-3.28) on multivariate competing risk regression analysis.

CONCLUSIONS

TBAD is associated with high 10-year mortality. Those at risk for aorta-related mortality have a clinical phenotype different from that of individuals at risk for nonaorta-related mortality. This information is important for building risk prediction models that account for competing mortality risks and to direct optimal and individualized surgical and medical management of TBAD.

Aortic Wall Enhancement Detected by Contrast Computed Tomography Scan Predicts Aortic Remodeling after Conservative Therapy for Acute Uncomplicated Type B Dissection

BACKGROUND

The Investigation of Stent Grafts in Aortic Dissection with extended length of follow-up trial showed that pre-emptive thoracic endovascular aneurysm repair (TEVAR) for the uncomplicated type B dissection (TBAD) in the subacute phase promotes aortic remodeling and avoids aortic-related death 5 years after onset. However, there are some patients with complete aortic remodeling (CAR) with optimal medical treatment (OMT) and severe complications after TEVAR such as retrograde type A dissection. Therefore, which patients should undergo pre-emptive TEVAR and optimal surgical timing are still under debate. We reported that aortic wall enhancement (AWE) after endovascular aneurysm repair for abdominal aortic aneurysm was associated with sac shrinkage. However, there is no report about the relationship between AWE and aortic dissection. Herein, we evaluated the relationship between AWE and acute TBAD.

METHODS

From March 2012 to May 2018, consecutive patients with acute TBAD were retrospectively collected. We retrospectively analyzed 35 patients with acute TBAD who were treated with OMT and without pre-emptive TEVAR in the subacute phase. AWE was defined as an increase of more than 20 Hounsfield units in mean computed tomography (CT) values, comparing images in delayed contrast-enhanced scans with those in plain scans evaluated within 3 months from onset. The measurement points were all slices including the wall of the false lumen. The patients with traumatic dissection, type A dissection, acute complicated type B dissection, chronic (>12 weeks) dissection, and those lost to follow-up within 3 months from onset were excluded. The primary end point was spontaneous CAR under OMT, as determined by the latest contrast-enhanced CT scan.

RESULTS

The median follow-up period from onset was 86 weeks and there were 25 cases (71.4%) with AWE. Under OMT, CAR was observed in 20 patients (57.1%); this was significantly associated with abdominal branch dissection (6/15 [40%] vs. 2/20 [10%], P = 0.050), number of tears more than 2 at onset (11/15 [73%] vs. 4/20 [20%], P = 0.003), multiple tears at 1 month after onset (9/15 [60%] vs. 4/20 [20%], P = 0.020), maximal false lumen diameter at 1 month after onset (14 vs. 8 mm, P = 0.025), and AWE within 3 months of onset (7/15 [47%] vs. 18/20 [90%], P = 0.010). Multivariate analysis demonstrated a significant difference with multiple tears at onset (P = 0.014) and AWE within 3 months of onset (P = 0.047).

CONCLUSIONS

AWE was associated with CAR under OMT for acute TBAD which is out of indication of pre-emptive TEVAR. Presence of AWE may be useful in predicting prognosis of TBAD.

Comparison of aortic remodelling after conservative treatment or thoracic endovascular repair in type B dissections

OBJECTIVES

Our aim was to compare aortic remodelling in type B dissections after thoracic endovascular aortic repair (TEVAR) or conservative treatment.

METHODS

We conducted a retrospective analysis of computed tomography (CT) data sets at dissection onset and at the last follow-up in a group with conservative (group A) and TEVAR treatment (group B). An additional analysis of the preoperative CT images was performed in patients from group A, who were converted to TEVAR during follow-up. Diameters and lengths of all aortic segments were measured and growth rates were calculated.

RESULTS

We included 74 patients: 50 patients in group A (follow-up time: 1625 ± 209 days) and 24 patients in group B (follow-up time: 554 ± 129 days). The mean aortic diameter growth rate was significantly higher in group A than in group B in the mid-descending aorta (A: +7 mm/year; B: -4 mm/year; P = 0.003). Length growth difference was only present in the abdominal aortic segment and was more pronounced in group A (+2 vs ±0 mm/year; P = 0.009). The conversion rate from conservative treatment to TEVAR was 36% (n = 18). A false lumen diameter of >22 mm at baseline was associated with a higher rate of conversion (P = 0.036). After conversion, the mean growth rate in the proximal descending and mid-descending aorta decreased from preoperative +11 and +18 mm/year to postoperative -9 and -14 mm/year, respectively (P < 0.001).

CONCLUSIONS

In acute type B dissections, TEVAR stops aortic enlargement in the thoracic aorta, but promotes distal dilatation compared to the conservative treatment group. After conversion to TEVAR in conservatively pretreated chronic type B dissections, a more pronounced diameter decrease in the descending aorta was observed than in patients treated in the acute phase.

Pre-emptive thoracic endovascular aortic repair is unnecessary in extended type A (DeBakey type I) aortic dissections

OBJECTIVE

Pre-emptive thoracic endovascular aortic repair (TEVAR) improves late survival and limits progression of disease after type B aortic dissection, but the potential value of pre-emptive TEVAR has not been evaluated after type A dissection extending beyond the aortic arch (DeBakey type I). The purpose of this study was to compare disease progression and need for aortic intervention in survivors of acute, extended type A (ExTA) dissections after initial repair of the ascending aorta versus acute type B aortic dissections.

METHODS

Consecutive patients presenting with ExTA or type B dissections between 2011 and 2018 were studied. Forty-three patients with ExTA and 44 with type B dissections who survived to discharge and had follow-up imaging studies were included in the analysis. Study end points included progression of aortic disease (>5 mm growth or extension), need for intervention, and death.

RESULTS

The groups were not different for age, sex, atherosclerotic risk factors, or extent of dissection distal to the left subclavian artery. Following emergent ascending aortic repair, five ExTA patients (12%) underwent TEVAR within 4 months after discharge. Despite optimal medical treatment, 29 type B patients (66%) underwent early or late TEVAR (P < .001). During a mean follow-up of 38 ± 30 months, 38 ExTA patients (88%) did not require intervention-23 (53%) of whom showed no disease progression. In comparison, during a mean follow-up of 18 ± 6 months, 14 type B patients (32%) did not require intervention-nine (20%) of whom showed no disease progression (P = .003). There was one aortic-related late death in the ExTA group and two in the type B group. Compared with ExTA patients, type B patients had significantly worse intervention-free survival and intervention/growth-free survival (log rank, P < .001).

CONCLUSIONS

In contrast with type B dissections, these midterm results demonstrate that one-half of ExTA aortic dissections show no disease progression in the thoracic or abdominal aorta, and few require additional interventions. After initial repair of the ascending aorta, pre-emptive TEVAR does not seem to be justified in patients with acute, ExTA dissections.

Long-term Results of Endovascular Treatment of Chronic Type B Aortic Dissection by Closure of the Primary Tear

BACKGROUND

The role of thoracic endovascular aortic repair (TEVAR) in the treatment of chronic type B aortic dissection is controversial. Some advocate open surgery, based on the premise that all tears must be treated, and others prefer branched endografts with the same premise. However, TEVAR, with closure of the primary tear in the thorax, has shown good results in some centers. This single-center cohort study was designed to contribute to the knowledge of the long-term evolution (mean, 4.8 years) of the patients submitted to endovascular closure of the proximal intimal tear.

METHODS

A total of 36 patients with asymptomatic chronic aortic dissection had a successful closure of the primary tear by TEVAR and were followed up for a median time of 57.2 months.

RESULTS

In 75% of the cases, there was stabilization or decrease in the maximum diameter. Twenty-five percent had diameter increase in the thoracic or abdominal aorta and indication for one or more additional procedures. One patient refused a second procedure and died from rupture one month after the last evaluation; this was the only case of rupture in the series. One patient died of unrelated cause before having been submitted to a second procedure. Thirty-four patients survived without diameter increase in the follow-up period.

CONCLUSIONS

Chronic type B aortic dissections can be successfully treated by the coverage of the proximal tear with an endograft. Patients shall be followed carefully, and 25% of them will require one or more additional procedures to achieve a good result.

Population-Based Assessment of the Incidence of Aortic Dissection, Intramural Hematoma, and Penetrating Ulcer, and Its Associated Mortality From 1995 to 2015

Background Aortic syndromes (ASs), including aortic dissection, intramural hematoma, and penetrating aortic ulcer, carry significant acute and long-term morbidity and mortality. However, the contemporary incidence and outcomes of AS are unknown. Methods and Results We used the Rochester Epidemiology Project record linkage system to identify all Olmsted County, MN, residents with AS (1995-2015). Diagnostic imaging, medical records, and death certificates were reviewed to confirm the diagnosis and AS subtype. Age- and sex-adjusted incidence rates were estimated using annual county-level census data. Survival for patients with AS was compared with age- and sex-matched controls using Cox regression to adjust for comorbid conditions. We identified 133 patients with AS (77, aortic dissection; 21, intramural hematoma; and 35, penetrating aortic ulcer). Average age was 71.8 years (SD=14.1), and 57% were men. The age- and sex-adjusted incidence was 7.7 per 100 000 person-years, was higher for men than women (10.2 versus 5.7 per 100 000 person-years), and increased with age. Among subtypes, the incidence of aortic dissection was highest (4.4 per 100 000 person-years), whereas the incidence of penetrating aortic ulcer and intramural hematoma was lower (2.1 and 1.2 per 100 000 person-years). Overall, the incidence of AS was stable over time ( P trend=0.33), although the incidence of penetrating aortic ulcer seemed to increase from 0.6 to 2.6 per 100 000 person-years ( P=0.008) with variability over the study interval. Patients with AS had more than twice the mortality rate at 5, 10, and 20 years when compared with population-based controls (5-, 10-, and 20-year mortality 39%, 57%, and 91% versus 18%, 41%, and 66%; overall adjusted mortality hazards ratio=2.1; P<0.001). Survival was lower than expected up to 90 days after AS diagnosis and did not differ significantly by subtype or by 5-year strata of diagnosis. Conclusions Overall, the incidence of aortic dissection and intramural hematoma has remained stable since 1995, despite the decline noted for other cardiovascular disease. AS confers increased early and long-term mortality that has not changed. These data highlight the need to improve long-term care to impact the prognosis of this patient group.

Left ventricular hypertrophy is a possible biomarker for early mortality after type B aortic dissection

OBJECTIVE

Data regarding the cardiac abnormalities associated with Stanford type B aortic dissection (TBAD) and whether these abnormalities are related to outcomes are limited. We describe the prevalence of cardiac abnormalities in patients with TBAD as detected by echocardiography.

METHODS

This retrospective review included patients with TBAD presenting between 1990 and 2016. Echocardiograms performed within 6 weeks of acute TBAD were reviewed. Cardiac function, valve abnormalities, and stigmata of hypertensive heart disease including left ventricular hypertrophy (LVH) were ascertained. Characteristics of patients who did and did not receive echocardiograms were compared. Outcomes of patients with and without evidence of LVH on echocardiography were also compared.

RESULTS

Of 239 patients with TBAD, 90 had echocardiograms performed within 6 weeks of acute TBAD (74% male; mean age, 57.8 ± 13.2 years). Echocardiograms were obtained at a median of 2 days (range, 0-41 days) from acute TBAD. Patients who had echocardiograms were more likely to present with malperfusion (28% vs 14%; P < .01) and had a trend toward increased operative repair during the subacute phase (17.4% vs 9.5%; P = .07) compared with patients who did not receive an echocardiogram. A majority of patients (57%) had at least mild LVH, including 39% of patients without a prior diagnosis of hypertension. Fibrocalcific changes associated with hypertension, including aortic sclerosis and mitral annular calcification, were noted in 40% and 11% of the patients, respectively. Among patients with LVH, there was a trend toward higher all-cause mortality (35% vs 23%; P = .21) and a younger age at death (58 ± 14 years vs 66 ± 13 years; P = .19) despite a similar age at TBAD onset. In a multivariable analysis controlling for age, sex, and admission estimated glomerular filtration rate, LVH independently predicted all-cause mortality (hazard ratio, 2.38; 95% confidence interval, 1.02-5.56; P = .04).

CONCLUSIONS

LVH and other findings of hypertensive heart disease are common in patients with TBAD. LVH predicted all-cause mortality after TBAD in this small group of patients. Further exploration of the relationship between the chronic effects of hypertension and using LVH as an objective biomarker to risk stratify patients with TBAD and long-term outcomes after TBAD is warranted.

Favorable remodeling after hybrid arch debranching and modified provisional extension to induce complete attachment technique in type a aortic dissection: A case report

RATIONALE

Type A aortic dissection (TAAD) usually requires emergency open repair of the ascending aorta. In cases of diffuse dissection that spreads along the descending and abdominal aorta (type I, DeBakey classification), the risk of aneurysmal degeneration varies between 30% and 50% during 5 years and increases even higher during a longer follow-up. Those patients might require complex intervention to prevent aortic rupture. A combination of hybrid arch debranching and the extended provisional extension to induce complete attachment (e-PETTICOAT) technique might be an available alternative in such cases. This is the first report of the successful use of the e-PETTICOAT technique for treating degenerative, diffuse TAAD.

PATIENT CONCERNS

Acute chest pain and syncope were the initial symptoms of diffuse TAAD in our 66-year-old female patient. Open replacement of the ascending aorta followed by surgical arch debranching was performed as a staged procedure. Unfortunately, progressive aneurysmal degeneration was revealed 6 months later in the thoracic, abdominal, and infrarenal aorta with the recurrence of chest and lumbar pain.

DIAGNOSES

Computed angiotomography revealed severe aneurysmal degeneration of aortic dissection in the thoracic and abdominal aorta.

INTERVENTION

The e-PETTICOAT enabled good remodeling and stopped degeneration.

OUTCOME

At the 2-year follow-up, good remodeling with complete false lumen thrombosis and a stable aortic size were confirmed.

LESSON

Lifelong follow-up in extensive TAAD should be considered. The e-PETTICOAT technique is an available alternative to fenestrated endovascular aortic repair for degenerative TAAD, as it promotes favorable remodeling after successful surgery of the ascending aorta.

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.

Role of Re-entry Tears on the Dynamics of Type B Dissection Flap

Mortality during follow-up after acute Type B aortic dissection is substantial with aortic expansion observed in over 59% of the patients. Lumen pressure differential is considered a prime contributing factor for aortic dilation after propagation. The objective of the study was to evaluate the relationship between changes in vessel geometry with and without lumen pressure differential post propagation in an ex vivo porcine model with comparison with patient clinical data. A pulse duplicator system was utilized to propagate the dissection within descending thoracic porcine aortic vessels for set proximal (%circumference of the entry tear: 40%, axial length: 2 cm) and re-entry (50% of distal vessel circumference) tear geometry. Measurements of lumen pressure differential were made along with quantification of vessel geometry (n = 16). The magnitude of mean lumen pressure difference measured after propagation was low (~ 5 mmHg) with higher pressures measured in false lumen and as anticipated the pressure difference approached zero after the creation of distal re-entry tear. False lumen Dissection Ratio (FDR) defined as arc length of dissected wall divided by arc length of dissection flap, had mean value of 1.59 ± 0.01 at pressure of 120/80 mmHg post propagation with increasing values with increase in pulse pressure that was not rescued with the creation of distal re-entry tear (p < 0.01). An average FDR of 1.87 ± 0.27 was measured in patients with acute Type B dissection. Higher FDR value (FDR = 1 implies zero dissection) in the presence of distal re-entry tear demonstrates an acute change in vessel morphology in response to the dissection independent of local pressure changes challenges the re-apposition of the aortic wall.

How should we manage type B aortic dissections?

Dissection of the descending aorta is a serious and potentially lethal event. Treatment options consist of medical therapy, open surgical replacement of the affected aorta and thoracic endovascular repair. In acute cases, medical treatment is started initially. When complicated, endovascular repair is generally considered as first choice treatment, except for connective tissue disorders where open surgery remains the standard. In stable, uncomplicated patients with risk factors for future aortic growth pre-emptive endovascular repair should be considered in the sub-acute phase of the dissection. The treatment strategy in chronic dissections is somewhat debated. Long-term results and aortic remodeling of endovascular repair are disappointing and open surgery remains the standard.

Endovascular management of chronic symptomatic aortic dissection with the Streamliner Multilayer Flow Modulator: Twelve-month outcomes from the global registry

OBJECTIVE

Reported are initial 12-month outcomes of patients with chronic symptomatic aortic dissection managed by the Streamliner Multilayer Flow Modulator (SMFM; Cardiatis, Isnes, Belgium). Primary end points were freedom from rupture- and aortic-related death, and reduction in false lumen index. Secondary end points were patency of great vessels and visceral branches, and freedom of stroke, paraplegia, and renal failure.

METHODS

Out of 876 SMFM implanted globally, we have knowledge of 542. To date, 312 patients are maintained in the global registry, of which 38 patients were identified as having an aortic dissection (12.2%). Indications included 35 Stanford type B dissections, two Stanford type A and B dissections, and one mycotic Stanford type B dissection.

RESULTS

There were no reported ruptures or aortic-related deaths. All cause survival was 85.3% Twelve-month freedom from neurologic events was 100%, and there were no incidences of end-organ ischemia, paraplegia or renal insult. Morphologic analysis exhibited dissection remodeling by a reduction in longitudinal length of the dissected aorta, and false lumen volume. A statistically significant reduction in false lumen index (P = .016) at 12 months, and a borderline significant increase in true lumen volume (P = .053) confirmed dissection remodeling.

CONCLUSIONS

The SMFM is an option in management of complex pan-aortic dissection. Results highlight SMFM implantation leads to dissection stabilization with no further aneurysm progression, and no retrograde type A dissection. Thoracic endovascular aneurysm repair by SMFM ensued in freedom from aortic rupture, neurologic stroke, paraplegia and renal failure. Further analysis of the global registry data will inform long-term outcomes.

Rapid Aneurysmal Sac Expansion Following Endovascular Repair of a Dissecting Thoracoabdominal Aneurysm

Endovascular repair of dissecting thoracoabdominal aneurysms (TAAA) is challenging and often requires multiple procedures. A 61-year-old man with a dissecting type-II TAAA treated first by placement of a thoracic endograft, and subsequently implantation of a fenestrated endograft. Six months postoperatively, a 10-mm increase of the aorta was observed. A reentry tear in left external iliac artery (EIA) was perfusing the false lumen in a retrograde fashion connecting with the endoleak caused by the inferior mesenteric artery and lumbar arteries. False lumen embolization of the left EIA and outflow vessels was performed. Thrombosis and rapid decrease of false lumen diameter was then observed. This case illustrates the complexity of endovascular management of extensive chronic aortic dissections.

The new indication of TEVAR for uncomplicated type B aortic dissection

The classical therapeutic indication for type B aortic dissection is based on either medication or open surgery; medication therapy is recommended for relatively stable uncomplicated type B aortic dissection. With improvements in endovascular repair and the potential risk of disease progression, it is now necessary to evaluate the requirement for revision of the therapeutic choice of uncomplicated type B aortic dissection based on morphological features and time window. Data from 252 patients diagnosed as uncomplicated type B aortic dissection from 1992 to 2015 were analyzed retrospectively. Among these cases, 117 patients received medication therapy and 135 patients underwent endovascular repair. The 60-month survival rate in the endovascular group was higher than that in the medication group (92.3% vs 67.6%). According to the morphological evaluation, visceral artery involvement and false/true lumen ratios over 0.7 were strong risk factors for medical treatment alone. Increased surgical time and blood loss were found in patients treated in the chronic phase, compared with those who underwent endovascular repair within 14 days of the onset of symptoms. With improvements in aortic remodeling techniques, endovascular repair has been shown to improve long-term survival rates of patients with uncomplicated aortic dissection. Considering the potential risk of death, we recommend that patients with visceral artery involvement and a false/true lumen ratio over 0.7 should receive endovascular repair aggressively. Furthermore, delayed endovascular repair in the chronic phase does not improve the long-term outcome of uncomplicated type B aortic dissection.