The natural history of medically managed acute type B aortic dissection

Early three-dimensional growth in uncomplicated type B aortic dissection is associated with long-term outcomes

OBJECTIVE

Late adverse events (LAEs) are common among initially uncomplicated type B aortic dissection (uTBAD); however, identifying those patients at highest risk of LAEs remains a significant challenge. Early false lumen (FL) growth has been suggested to increase risk, but confident determination of growth is often hampered by error in two-dimensional clinical measurements. Semi-automated three-dimensional (3D) mapping of aortic growth, such as by vascular deformation mapping (VDM), can potentially overcome this limitation using computed tomography angiograms (CTA). We hypothesized that FL growth in the early pre-dissection phase by VDM can accurately predict LAEs.

METHODS

We performed a two-center retrospective study of patients with uTBAD, with paired CTAs in the acute (1-14 days) and subacute/early chronic (1-6 months) periods. VDM analysis was used to map 3D growth. Standard clinical CT measures (ie, aortic diameters, tear characteristics) were also collected. Multivariate analysis was conducted using a decision tree and Cox proportional hazards model. LAEs were defined as aneurysmal FL (>55 mm); rapid growth (>5 mm within 6 months); aorta-specific mortality, rupture, or re-dissection.

RESULTS

A total of 107 (69% male) patients with uTBAD initially met inclusion criteria with a median follow-up of 7.3 years (interquartile range [IQR], 4.7-9.9 years). LAEs occurred in 72 patients (67%) at 2.5 years (IQR, 0.7-4.8 years) after the initial event. A multivariate decision tree model identified VDM growth (>2.1 mm) and baseline diameter (>42.7 mm) as optimal predictors of LAEs (area under the receiver operating characteristic curve = 0.94), achieving an 87% accuracy (sensitivity of 93%, specificity of 76%) after leave-one-out validation. Guideline reported high-risk features were not significantly different between groups.

CONCLUSIONS

Early growth of the FL in uTBAD was the best tested indicator for LAEs and improves upon the current gold-standard of baseline diameter in selecting patients for early prophylactic thoracic endovascular aortic repair.

Post-dissection Thoraco-abdominal Aortic Aneurysm Managed by Fenestrated or Branched Endovascular Aortic Repair

OBJECTIVE

Fenestrated or branched endovascular aortic repair (F/B-EVAR) is a valuable treatment in patients with chronic post-dissection thoraco-abdominal aneurysm (PD-TAAA). This study aimed to analyse early and follow up outcomes of F/B-EVAR in these patients.

METHODS

Thirty day and follow up outcomes of consecutive patients with PD-TAAA treated with F/B-EVAR in a tertiary centre over eight years were analysed retrospectively. All patients presenting with PD-TAAA and managed with F/B-EVAR were eligible. A modified Crawford's classification system was used. Thirty day mortality and major adverse event (MAE) rates were analysed. Time to event data were estimated with Kaplan-Meier survival analysis.

RESULTS

Fifty five patients (80% men, mean age 63.7 ± 7.7 years) were included: 12 (22%) were managed urgently; 25 (46%) for chronic type B aortic dissection; and the remainder for residual type A aortic dissection. Of these patients, 88% had undergone previous thoracic endovascular aortic repair. Prophylactic cerebrospinal fluid drainage (CSFD) was used in 91%. Fifteen (27%) patients were treated with F-EVAR, nine (16%) with fenestrations and branches, and 31 (56%) with B-EVAR. False lumen adjunctive procedures were used in 56%. Technical success was achieved in 96% of patients. The thirty day mortality rate was 7% and MAE rate was 20%. Spinal cord injury (SCI) grades 1 - 3 and grade 3 rates were 13% and 2%, respectively. Mean follow up was 33.0 ± 18.4 months. Survival and freedom from unscheduled re-intervention were 86% (standard error [SE] 5%) and 55% (SE 8%) at 24 months, respectively. Freedom from target vessel stenosis and occlusion was higher in F-EVAR at the 12 month follow up (p = .006) compared with B-EVAR.

CONCLUSION

Fenestrated or branched endovascular repairs in patients with PD-TAAA showed high technical success, with acceptable early mortality and MAE rates. The SCI rate was > 10%, despite CSFD use and staged procedures. Almost a half of patients needed an unscheduled re-intervention within 24 months after F/B-EVAR.

Interval changes in four-dimensional flow-derived in vivo hemodynamics stratify aortic growth in type B aortic dissection patients

BACKGROUND

Aortic diameter growth in type B aortic dissection (TBAD) is associated with progressive aortic dilation, resulting in increased mortality in patients with both de novo TBAD (dnTBAD) and residual dissection after type A dissection repair (rTAAD). Preemptive thoracic endovascular aortic repair may improve mortality in patients with TBAD, although it is unclear which patients may benefit most from early intervention. In vivo hemodynamic assessment using four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) has been used to characterize TBAD patients with growing aortas. In this longitudinal study, we investigated whether changes over time in 4D flow-derived true and false lumen (TL and FL) hemodynamic parameters correlate with aortic growth rate, which is a marker of increased risk.

METHODS

We retrospectively identified TBAD patients with baseline and follow-up 4D flow CMR at least 120 days apart. Patients with TBAD intervention before baseline or between scans were excluded. 4D flow CMR data analysis included segmentation of the TL and FL, followed by voxel-wise calculation of TL and FL total kinetic energy (KE), maximum velocity (MV), mean forward flow (FF), and mean reverse flow (RF). Changes over time (Δ) were calculated for all hemodynamic parameters. Maximal diameter in the descending aorta was measured from magnetic resonance angiogram images acquired at the time of 4D flow. Aortic growth rate was defined as the change in diameter divided by baseline diameter and standardized to scan interval.

RESULTS

Thirty-two patients met inclusion criteria (age: 56.9 ± 14.1 years, female: 13, n = 19 rTAAD, n = 13 dnTBAD). Mean follow-up time was 538 days (range: 135-1689). Baseline aortic diameter did not correlate with growth rate. In the entire cohort, Δ FL MV (Spearman's rho [rho] = 0.37, p = 0.04) and Δ FL RF (rho = 0.45, p = 0.01) correlated with growth rate. In rTAAD only, Δ FL MV (rho = 0.48, p = 0.04) and Δ FL RF (rho = 0.51, p = 0.03) correlated with growth rate, while in dnTBAD only, Δ TL KE (rho = 0.63, p = 0.02) and Δ TL MV (rho = 0.69, p = 0.01) correlated with growth rate.

CONCLUSION

4D flow-derived longitudinal hemodynamic changes correlate with aortic growth rate in TBAD and may provide additional prognostic value for risk stratification. 4D flow MRI could be integrated into existing imaging protocols to allow for the identification of TBAD patients who would benefit from preemptive surgical or endovascular intervention.

Navigating clinical appropriateness: A review of management strategies for type B aortic dissection

Aortic dissection is a catastrophic, life-threatening event. Its management depends on the anatomic location of the intimal tear (type A v B) and the clinical presentation in type B aortic dissection. In this article, the current evidence supporting clinical practice, gaps in knowledge, and the need for more rigorous research and higher-quality studies are reviewed.

Trends in the incidence, surgical management and outcomes of type B aortic dissections in Australia over the last decade

OBJECTIVES

This study aims to investigate the incidence and in-hospital outcomes of surgical repair for type B aortic dissection (TBAD) in Australia.

METHODS

Data were obtained from the Australasian Vascular Audit (AVA) and the Australian Institute of Health and Welfare (AIHW). The former is a total practice audit mandated for all members of the Australian and New Zealand Society for Vascular Surgery (ANZSVS) while the latter is an independent government agency which records all healthcare data in Australia. All cases of TBAD which underwent surgical intervention (endovascular or open repair) between 2010 and 2019 were identified using prospectively recorded data from the AVA (New Zealand data was excluded). The primary outcomes were temporal trends in procedures and hospital mortality; secondary outcomes were complications and risk factors for mortality. All admissions and procedures for, and hospital deaths from, TBAD in Australia were identified in AIHW datasets using the relevant diagnosis and procedure codes, with age-standardized rates calculated for the period 2000-01 to 2018-19.

RESULTS

A total of 567 cases of TBAD underwent vascular surgical intervention (AVA data, Australia). Of these, 96.3% were treated by endovascular repair. There was an increase in the annual procedure number from 45 in 2010 to 88 in 2019. In-hospital mortality was 4.8% for endovascular repair and 19% for open repair (p = 0.021). From 2000-01 to 2018-19, the age-standardized procedure rates for TBAD (Australia) doubled, the proportion of admitted patients undergoing a procedure rose from 28% to 43%, and in-hospital deaths fell by 25%.

CONCLUSION

There has been an increasing incidence of vascular surgical intervention for TBAD in Australia. The majority of patients received endovascular therapy while the mortality from surgically managed TBAD appears to be falling.

Dietary vitamin C and vitamin E with the risk of aortic aneurysm and dissection: A prospective population-based cohort study

BACKGROUND AND AIMS

The associations between dietary vitamin C (VC), vitamin E (VE) intake and aortic aneurysm and dissection (AAD) remain unclear. This study aimed to prospectively investigate the associations between dietary VC and VE with the incident risk of AAD.

METHODS AND RESULTS

A total of 139 477 participants of UK Biobank cohort were included in the analysis. Dietary VC and VE consumptions were acquired through a 24-h recall questionnaire. Cox proportional regression models were used to examine the associations between VC, VE intake and the risk of AAD. Incident AAD was ascertained through hospital inpatient records and death registers. During a median follow-up of 12.5 years, 962 incident AAD events were documented. Both dietary VC [adjusted hazard ratio (HR), 0.77; 95 % confidence intervals (CI), 0.63-0.93; P-trend = 0.008] and VE (adjusted HR, 0.70; 95 % CI, 0.57-0.87; P-trend = 0.002) were inversely associated with incident AAD when comparing the participants in the highest quartile with those in the lowest. In subgroup analyses, the associations were more pronounced in participants who were over 60 years old, participants with smoking history, hypertension or hyperlipidemia, who were under the high risk of AAD.

CONCLUSION

Higher dietary VC and VE intakes are associated with reduced risk of AAD. Our study emphasizes the importance of diet adjustment strategies targeted on VC and VE to lower the incidence rate of AAD especially in the high-risk population.

Preemptive treatment in the acute and early subacute phase of uncomplicated type B aortic dissections with poor prognosis factors

Objective

Due to its favorable outcome regarding late morbidity and mortality, thoracic endovascular repair (TEVAR) is becoming more popular for uncomplicated type B aortic dissection (TBAD). This study aimed to compare preemptive endovascular treatment and optimal medical treatment (OMT) and OMT alone in patients presenting uncomplicated TBAD with predictors of aortic progression.

Design

Retrospective multicenter study.

Methods

We analyzed patients with uncomplicated TBAD and risk factors of progression in two French academic centers. Aortic events [defined as aortic-related (re)intervention or aortic-related death after initial hospitalization], postoperative complications, non-aortic events, and radiologic aortic progression and remodeling were recorded and analyzed. Analysis was performed on an intention-to-treat basis.

Results

Between 2011 and 2021, preemptive endovascular procedures at the acute and early subacute phase (<30 days) were performed on 24 patients (group 1) and OMT alone on 26 patients (group 2). With a mean follow-up of 38.08 ± 24.53 months, aortic events occurred in 20.83% of patients from group 1 and 61.54% of patients from group 2 (p < .001). No patient presented aortic-related death during follow-up. There were no differences in postoperative events (p = 1.00) and non-aortic events (p = 1.00). OMT patients had significantly more aneurysmal progression of the thoracic aorta (p < .001) and maximal aortic diameter (p < .001). Aortic remodeling was found in 91.67% of patients in group 1 and 42.31% of patients in group 2 (p < .001). A subgroup analysis of patients in group 1 showed that patients treated with preemptive TEVAR and STABILISE had reduced maximum aortic diameters at the 1-year (p = .010) and last follow-up (p = .030) compared to those in patients treated with preemptive TEVAR alone.

Conclusion

Preemptive treatment of uncomplicated TBAD with risk factors of progression reduces the risk of long-term aortic events. Over 60% of medically treated patients will require intervention during follow-up, with no benefit in terms of postoperative events. Even after surgical treatment, patients in the OMT group had significantly more aneurysmal progression, along with poorer aortic remodeling.

Current perspectives in acute type B aortic dissections: a literature review

In this new millennial, endovascular strategies have revolutionized the treatment of acute type B aortic dissection (aTBAD). With reduced in-hospital mortality and good long-term outcomes TEVAR has become the gold standard for the treatment of complicated dissection and is gaining increasing support for its preventive applicability in some uncomplicated dissections. With this new paradigm came a shift of the treatment goal where just covering the entry tear is not enough and instead achieving long-term positive thoracoabdominal remodeling is needed. More extensive approaches with composite device designs (covered stent graft and bare metal stent) emerged to answer this aortic conundrum. At 5-year of follow-up, "Provisional ExTension To Induce COmplete Attachment technique" (PETTICOAT) and its evolution "Stent assisted balloon induced intimal disruption and relamination in aortic dissection repair" (STABILISE) seem to be safe techniques that can allow, when anatomically feasible, excellent aortic remodeling and, in some cases, even the healing of the dissection. Nevertheless, STABILISE results, although promising, are mostly based on small series and therefore need to be validated by analyzing medium-long-term results from the international registry. Given the plethora of new data and the disparity of expert opinions on the best treatment to adopt, in this review we aim to summarize the current knowledge on the results of these different strategies for acute TBAD.

The role of anatomic shape features in the prognosis of uncomplicated type B aortic dissection initially treated with optimal medical therapy

OBJECTIVE

Currently, the long-term outcomes of uncomplicated type B aortic dissection (TBAD) patients managed with optimal medical therapy (OMT) remain poor. Aortic expansion is a major factor that determines patient long-term survival. The objective of this study was to investigate the association between anatomic shape features and (i) OMT outcome; (ii) aortic growth rate for TBAD patients initially treated with OMT.

METHODS

108 CT images of TBAD in the acute and chronic phases were collected from 46 patients who were initially treated with OMT. Statistical shape models (SSM) of TBAD were constructed to extract shape features from the earliest initial CT scans of each patient by using principal component analysis (PCA) and partial least square (PLS) regression. Additionally, conventional shape features (e.g., aortic diameter) were quantified from the earliest CT scans as a baseline for comparison. We identified conventional and SSM features that were significant in separating OMT "success" and failure patients. Moreover, the aortic growth rate was predicted by SSM and conventional features using linear and nonlinear regression with cross-validations.

RESULTS

Size-related SSM and conventional features (mean aortic diameter: p=0.0484, centerline length: p=0.0112, PCA score c1: p=0.0192, and PLS scores t1: p=0.0004, t2: p=0.0274) were significantly different between OMT success and failure groups, but these features were incapable of predicting the aortic growth rate. SSM shape features showed superior results in growth rate prediction compared to conventional features. Using multiple linear regression, the conventional, PCA, and PLS shape features resulted in root mean square errors (RMSE) of 1.23, 0.85, and 0.84 mm/year, respectively, in leave-one-out cross-validations. Nonlinear support vector regression (SVR) led to improved RMSE of 0.99, 0.54, and 0.43 mm/year, for the conventional, PCA, and PLS features, respectively.

CONCLUSION

Size-related shape features of the earliest scan were correlated with OMT failure but led to large errors in the prediction of the aortic growth rate. SSM features in combination with nonlinear regression could be a promising avenue to predict the aortic growth rate.

A Systematic Review and an Updated Meta-Analysis of Fenestrated/Branched Endovascular Aortic Repair of Chronic Post-Dissection Thoracoabdominal Aortic Aneurysms

The objective of this study is to present the current outcomes of fenestrated/branched endovascular repair (F/BEVAR) for post-dissection thoracoabdominal aortic aneurysms (PDTAAAs). A systematic review of the literature according to PRISMA guidelines up to October 2023 was conducted (protocol CRD42023473403). Studies were included if ≥10 patients were reported and at least one of the major outcomes was stated. A total of 10 studies with 585 patients overall were included. The pooled estimate for technical success was 94.3% (95% CI 91.4% to 96.2%). Permanent paraplegia developed with a pooled rate of 2.5% (95% CI 1.5% to 4.3%), whereas a cerebrovascular event developed with a pooled rate of 1.6% (95% CI 0.8% to 3.0%). An acute renal function impairment requiring new-onset dialysis occurred with a pooled rate of 2.0% (95% CI 1.0% to 3.8%). Postoperative respiratory failure was observed with a pooled estimate of 5.5% (95% CI 3.8% to 8.1%). The pooled estimate for 12-month overall survival was 90% (95% CI 85% to 93.5%), and the pooled estimates for 24-month and 36-month survival were 87.8% (95% CI 80.9% to 92.5%) and 85.5% (95% CI 76.5% to 91.5%), respectively. Freedom from reintervention was estimated at 83.9% (95% CI 75.9% to 89.6%) for 12 months, 82.8% (95% CI 68.7% to 91.4%) for 24 months and 76.1% (95% CI 60.6% to 86.8%) for 36 months. According to the present findings, F/BEVAR can be performed in PD-TAAAs with high rates of technical success and good mid-term results.

Systemic immune-inflammation index predicts the clinical outcomes in patients with acute uncomplicated type-B aortic dissection undergoing optimal medical therapy

BACKGROUND

Optimal medical therapy (OMT) for uncomplicated type B aortic dissection (uTBAD) provides excellent short-term outcomes during follow up; however, its long-term therapeutic effectiveness is unsatisfactory. This study evaluated the predictive value of systemic immune-inflammation index (SII) for adverse events among patients with acute uTBAD undergoing OMT.

METHODS

We performed a retrospective analysis of a prospectively maintained database between 2013 and 2020. The primary end point in this study was composite outcomes including aortic intervention, all-cause mortality, retrograde type A aortic dissection (rTAAD) and aortic diameter growth > 5 mm. The patients were divided into high and low SII groups according to the optimal cut-off value of SII as determined using the receiver operating characteristic curve. Cox proportional hazards models were constructed to estimate the hazards ratios and identify the predictors of composite outcomes.

RESULTS

A total of 124 patients with acute uTBAD who underwent OMT were enrolled. One patient died during hospitalisation. At the end of a mean follow-up duration of 51 ± 23 months, 53 (43.1%) patients experienced composite outcomes, 15 patients (12.2%) died, 31 (25.2%) underwent aortic intervention, 21 (17.1%) exhibited diameter growth of > 5 mm, and 2 developed rTAAD. The patients were divided into low SII group (n = 78, 62.9%) and high SII group (n = 46, 37.1%) as per the optimal cut-off SII value of 1449. The incidence of composite outcomes in high SII group was significantly higher than that in low SII (28 [60.9%] vs. 26[33.3%], p < 0.01). Patients with high SII demonstrated significantly higher mortality rate than those with a low SII (11 [23.9%] vs. 5 [6.4%], respectively; p < 0.01). In addition, the high SII group had significantly higher rate of aortic-related reinterventions than the low SII group (16 [34.8%] vs. 15 [19.2%], p = 0.03). Multivariable Cox analyses showed that a high SII score was independently associated with composite outcomes rate (hazard ratio, 2.15; 95% confidence interval, 1.22-3.78; p < 0.01).

CONCLUSIONS

The long-term therapeutic effectiveness of OMT alone in patients with acute uTBAD is unsatisfactory. An SII > 1449 at the time of diagnosis is an independent predictor of OMT failure.

Late Referral and Patient Transfer is Associated with Worse Outcomes for Patients Presenting with Initially Uncomplicated Type B Aortic Dissections

BACKGROUND

Acute type B aortic dissections (TBADs) can become complicated at any time point, necessitating surgical repair. We sought to investigate the effect of interhospital transfer on the development of delayed complications in acute type B aortic dissection (dcTBAD).

METHODS

All patients who presented with acute TBAD to a tertiary aortic center from 2015 to 2019 were analyzed. Patients were divided into initially complicated type B aortic dissection (icTBAD) (0-24 hours from symptom onset), dcTBAD (25 hours to 14 days), and uncomplicated type B aortic dissection (ucTBAD) groups. Criteria for complicated dissection were aortic rupture, malperfusion, or rapid aortic growth. Demographics, patient history, the timing of presentation, imaging findings, and clinical outcomes were compared between groups.

RESULTS

Of 120 acute TBADs included, 27 (22%) were initially complicated (aortic rupture, n = 9; malperfusion, n = 18). Twenty-one (18%) developed delayed complications (aortic rupture, n = 3; malperfusion, n = 14; rapid growth, n = 4) at a median of 7.0 [4.0, 9.0] days from symptom onset. Seventy-two (60%) remained uncomplicated. Overall, 111 (93%) presented as transfers from outside hospitals (icTBAD, n = 25; dcTBAD, n = 21; ucTBAD, n = 65). Of those, dcTBADs were more likely to have a prolonged delay between presentation to the outside hospital and referral to the tertiary center compared to ucTBADs (median = 1.00 [0.0, 5.0] days delayed vs. 0.00 [0.0, 0.0] days delayed; P < 0.001). Initially uncomplicated patients referred for transfer ≥24 hours from presentation went on to develop dcTBAD more often than those transferred in <24 hours (73% vs 13%; P < 0.001). Of dcTBADs, 38% had no high-risk features on initial imaging. Patients with dcTBAD had significantly longer length of stay (median = 12 vs 7 days; P = 0.006). In-hospital mortality was significantly higher in dcTBADs than ucTBADs (9.5% vs 0%; P = 0.047). In-hospital mortality was not significantly different between dcTBADs and icTBADs (9.5% vs. 11%; P > 0.05).

CONCLUSIONS

The incidence and consequence of dcTBADsare not insignificant. Late referral and transfer to a tertiary aortic center (≥24 hours from initial presentation) was associated with dcTBADsrequiring surgical intervention. The development of dcTBADwas associated with increased length of stay and increased in-hospital mortality.

Self-pay insurance status is associated with failure of medical therapy in patients with acute uncomplicated type B aortic dissection

BACKGROUND

Traditionally, acute uncomplicated type B aortic dissections are managed medically, and acute complicated dissections are managed surgically. Self-pay patients with medically managed acute uncomplicated type B aortic dissections may fare worse than their insured counterparts.

METHODS

In this single-center, retrospective cohort study, demographics, follow-up, and outcomes of patients with acute type B aortic dissections from 2011 to 2020 were analyzed.

RESULTS

In total, 159 patients presented with acute type B aortic dissections; 102 were complicated and managed with thoracic endovascular aortic repair, and 57 were uncomplicated and managed medically. A total of 32% (n = 51) were self-pay. Self-pay patients were from areas with worse area deprivation indices (71% vs 63%, P = .024). They more often reported alcohol abuse (28% vs 7%, P < .001), cocaine/methamphetamine use (16% vs 5%, P = .028), and nonadherence to home antihypertensives (35% vs 11%, P < .001). Self-pay patients less often had a primary care physician (65% vs 7%, P < .001) or took antihypertensives before admission (31% vs 58%, P = .003). Self-pay patients frequently required financial assistance at discharge (63%), most often using charity funds (46%). Few patients (7%) qualified for our hospital's financial assistance program, and most (78%) remained uninsured at the first follow-up. Self-pay acute uncomplicated type B aortic dissections patients had the lowest rate of follow-up (31% vs 66%, P < .001) and were more likely to represent emergently (75% vs 0%, P = .033) compared to insured acute uncomplicated type B aortic dissections patients. Self-pay patients were more likely to follow up after thoracic endovascular aortic repair for acute complicated type B aortic dissections (82% vs 31%, P < .001).

CONCLUSION

Self-pay patients have multiple, interconnected, complex socioeconomic factors that likely influence preadmission risk for dissection and post-discharge adherence to optimal medical management. Further research is needed to clarify treatment strategies in this high-risk group.

A comparison of endovascular repair to medical management for acute vs subacute uncomplicated type B aortic dissections

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has emerged as a viable option of treatment for uncomplicated type B aortic dissection (UTBAD) due to the potential for inducing favorable aortic remodeling. The aim of this study is to compare outcomes of UTBAD treated medically or with TEVAR in either the acute (1 to 14 days) or subacute period (2 weeks to 3 months).

METHODS

Patients with UTBAD between 2007 and 2019 were identified using the TriNetX Network. The cohort was stratified by treatment type (medical management; TEVAR during the acute period; TEVAR during the subacute period). Outcomes including mortality, endovascular reintervention, and rupture were analyzed after propensity matching.

RESULTS

Among 20,376 patients with UTBAD, 18,840 were medically managed (92.5%), 1099 patients were in the acute TEVAR group (5.4%), and 437 patients were in the subacute TEVAR group (2.1%). The acute TEVAR group had higher rates of 30-day and 3-year rupture (4.1% vs 1.5%; P < .001; 9.9% vs 3.6%; P < .001) and 3-year endovascular reintervention (7.6% vs 1.6%; P < .001), similar 30-day mortality (4.4% vs 2.9%; P < .068), and lower 3-year survival compared with medical management (86.6% vs 83.3%; P = .041). The subacute TEVAR group had similar rates of 30-day mortality (2.3% vs 2.3%; P = 1), 3-year survival (87.0% vs 88.8%; P = .377) and 30-day and 3-year rupture (2.3% vs 2.3%; P = 1; 4.6% vs 3.4%; P = .388), with significantly higher rates of 3-year endovascular reintervention (12.6% vs 7.8%; P = .019) compared with medical management. The acute TEVAR group had similar rates of 30-day mortality (4.2% vs 2.5%; P = .171), rupture (3.0% vs 2.5%; P = .666), significantly higher rates of 3-year rupture (8.7% vs 3.5%; P = .002), and similar rates of 3-year endovascular reintervention (12.6% vs 10.6%; P = .380) compared with the subacute TEVAR group. There was significantly higher 3-year survival (88.5% vs 84.0%; P = .039) in the subacute TEVAR group compared with the acute TEVAR group.

CONCLUSIONS

Our results found lower 3-year survival in the acute TEVAR group compared with the medical management group. There was no 3-year survival benefit found in patients with UTBAD who underwent subacute TEVAR compared with medical management. This suggests the need for further studies looking at the necessity for TEVAR when compared with medical management for UTBAD as it is non-inferior to medical management. Higher rates of 3-year survival and lower rates of 3-year rupture in the subacute TEVAR group compared with the acute TEVAR group suggest superiority of subacute TEVAR. Further investigations are needed to determine the long-term benefit and optimal timing of TEVAR for acute UTBAD.

Editor's Choice - Optimal Timing of Thoracic Endovascular Aortic Repair for Uncomplicated Type B Aortic Dissection: A Systematic Review and Meta-Analysis

OBJECTIVE

Type B aortic dissections (TBAD) have a high mortality rate and are challenging to both classify and manage. There is significant evidence supporting the use of early intervention in complicated TBAD with thoracic endovascular aortic repair (TEVAR). Currently, there is equipoise regarding the optimal timing for TEVAR in TBAD. This systematic review answers whether early TEVAR in the hyperacute or acute phase of the disease has improved aorta related events in the one year follow up period with no change in mortality rate when compared with TEVAR in the subacute or chronic phase.

DATA SOURCES

A systematic review and meta-analysis was performed with Preferred Reporting Items for Systematic Reviews and Meta-Analyses literature search guidelines for MEDLINE, Embase, and Cochrane Reviews until 12 April 2021. Inclusion and exclusion criteria targeting the review objective and high quality research were employed by separate authors.

REVIEW METHODS

These studies were then reviewed for suitability, risk of bias, and heterogeneity using the ROBINS-I tool. Results were extracted for the meta-analysis with RevMan using odds ratios with 95% confidence intervals with I2 used to assess heterogeneity.

RESULTS

Twenty articles were included. A meta-analysis showed no significant difference between acute phase TEVAR (excluding the hyperacute phase) and subacute or chronic phase TEVAR for the all cause 30 day and one year mortality rates. Aorta related events in the 30 day post-operative period were unaffected by the timing of intervention but had significant improvement in aorta related events in the one year follow up favouring TEVAR in the acute phase compared with subacute or chronic phase. Risk of confounding was high but with low heterogeneity.

CONCLUSION

Without prospective randomised controlled studies, it is evident that there is improved aortic remodelling in long term follow up with intervention in the acute setting from three to 14 days after symptom onset. This suggests that TEVAR in the acute period of TBAD is both safe and beneficial, and can be considered for early stent grafting based on clinical, anatomical and patient factors.

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.

Acute aortic dissection

Although substantial progress has been made in the prevention, diagnosis, and treatment of acute aortic dissection, it remains a complex cardiovascular event, with a high immediate mortality and substantial morbidity in individuals surviving the acute period. The past decade has allowed a leap forward in understanding the pathophysiology of this disease; the existing classifications have been challenged, and the scientific community moves towards a nomenclature that is likely to unify the current definitions according to morphology and function. The most important pathophysiological pathway, namely the location and extension of the initial intimal tear, which causes a disruption of the media layer of the aortic wall, together with the size of the affected aortic segments, determines whether the patient should undergo emergency surgery, an endovascular intervention, or receive optimal medical treatment. The scientific evidence for the management and follow-up of acute aortic dissection continues to evolve. This Seminar provides a clinically relevant overview of potential prevention, diagnosis, and management of acute aortic dissection, which is the most severe acute aortic syndrome.

Advanced risk prediction for aortic dissection patients using imaging-based computational flow analysis

Patients with either a repaired or medically managed aortic dissection have varying degrees of risk of developing late complications. High-risk patients would benefit from earlier intervention to improve their long-term survival. Currently serial imaging is used for risk stratification, which is not always reliable. On the other hand, understanding aortic haemodynamics within a dissection is essential to fully evaluate the disease and predict how it may progress. In recent decades, computational fluid dynamics (CFD) has been extensively applied to simulate complex haemodynamics within aortic diseases, and more recently, four-dimensional (4D)-flow magnetic resonance imaging (MRI) techniques have been developed for in vivo haemodynamic measurement. This paper presents a comprehensive review on the application of image-based CFD simulations and 4D-flow MRI analysis for risk prediction in aortic dissection. The key steps involved in patient-specific CFD analyses are demonstrated. Finally, we propose a workflow incorporating computational modelling for personalised assessment to aid in risk stratification and treatment decision-making.

Treatment of thoracoabdominal aortic aneurysmal degeneration following aortic dissections at a single surgical center using a physician-assembled branched endovascular stent graft

OBJECTIVE

Aneurysmal degeneration of aortic dissection portends significant morbidity and mortality consequences in the subacute and chronic phases of aortic dissection. This paper describes the use of a multi-branched stent graft system for the treatment of thoracoabdominal aneurysmal degeneration of dissections with visceral segment involvement and reports upon the 30-day and one-year outcomes for the first 18 patients treated with this design configuration.

METHODS

The in-hospital, 30-day and one-year morbidity and mortality outcomes of 18 consecutive patients treated with the physician-assembled visceral manifold or unitary manifold stent graft systems between 2013 and 2022 were evaluated.

RESULTS

A total of 18 patients were treated for aneurysmal changes after aortic dissection. A total of 71 visceral vessels were successfully stented. There were no acute procedural failures. There were no episodes of paraplegia, reinterventions for type I or III endoleaks, patency-related events or mortalities reported in the first 30 days following treatment. One-year, all-cause mortality demonstrated 2/11 (18.2%).

CONCLUSIONS

Aneurysmal degeneration of aortic dissection poses significant risks to patients with medically managed aortic dissections and those under surveillance. When these aneurysms develop in the thoracoabdominal region, treatment becomes even more challenging given the problem of visceral vessel patency, as these vessels can originate off the true or false lumens. The physician-designed endovascular stent graft system reported upon here has been successfully deployed in 18 patients with no acute procedural failures and promising clinical results. This treatment modality may offer utility to vascular surgeons whose patients with thoracoabdominal aneurysmal degeneration following aortic dissection have historically had limited endovascular repair prospects.

Aortic arch surgery for type B aortic dissection: How far should we go? The value of a hybrid approach

Traditionally, the management of type B aortic dissection has been the domain of the vascular surgeons. Timing and type of intervention still generate debate. We sought to review our early experience with the treatment of this condition based on a hybrid approach following an aortic multi-disciplinary team meeting involving close cooperation between cardiac surgeons, vascular surgeons, interventional radiologists, vascular anesthetists, and cardiac anesthetists. Four patients (age 41-56 years; 3 males; 1 female) with type B aortic dissection underwent aortic arch surgery through a hybrid approach: one elective procedure consisting of ascending aorta and hemi-arch replacement with debranching followed by thoracic endovascular aortic repair (TEVAR); one redo procedure requiring aortic arch replacement with hybrid frozen elephant trunk; two acute presentations (aortic arch replacement and debranching followed by TEVAR; AVR with ascending aorta, arch, and proximal descending thoracic aorta replacement with conventional elephant trunk and debranching). Deep hypothermic circulatory arrest was required in three patients. Despite respiratory complications and slightly prolonged postoperative course, all patients survived without onset of stroke, paraplegia, malperfusion, endoleak, or need for re-exploration. Follow-up remains satisfactory. Different factors may affect outcome following complex aortic procedures. Nevertheless, close cooperation between cardiac surgeons, vascular surgeons, and interventional radiologists may reduce potential for complications and address aspects that may not be completely within the domain of individual specialists.

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.

Mid-Term Outcomes of a Hybrid Approach Involving Open Surgery Plus TEVAR of the Descending Aorta in the Treatment of Complex Type A Dissection

OBJECTIVES

Type A aortic dissection with true lumen collapse and malperfusion downstream is associated with a devastating prognosis. This study compares the clinical outcomes of two operative strategies for this disease: hybrid approach of ascending aorta (and hemiarch replacement) supplemented with retrograde stenting of the descending aorta (thoracic endovascular aortic repair [TEVAR]) and standard ascending aorta (and hemiarch) replacement without stent placement.

METHODS

From January 1, 2016 to December 31, 2019, 81 patients with type A aortic dissection were studied. The hybrid technique was applied in 30 patients (group 1), while 51 patients received standard surgical repair (group 2). Patient demographics, clinical and operative findings, postoperative outcome, follow-up interventions, and mid-term survival were analyzed.

RESULTS

Baseline characteristics were similar among the groups, except that more preoperative malperfusion was evident in group 1. The postoperative incidence of visceral malperfusion (0 vs. 15.7%, p = 0.02) and low cardiac output syndrome requiring extracorporeal membrane oxygenation support (3.3 vs. 19.6%, p = 0.04) was significantly less in group 1. In-hospital mortality was also significantly lower in group 1 as in group 2 (13.3 vs. 33.3%, p = 0.04). At follow-up, the need for secondary endovascular stenting (3.3 vs. 7.8%, p = 0.65) and surgical aortic reintervention (6.7 vs. 2.0%, p = 0.55) was comparable. One-year, 2-year, and 3-year survival rates were 83.3, 83.3, and 62.5% in group 1, and 58.7, 58.7, and 52.6% in group 2 (p = 0.05), respectively.

CONCLUSION

The combination of open surgical replacement of the ascending aorta (and hemiarch) with TEVAR of the descending aorta for true lumen compromise is a feasible treatment option for patients with type A aortic dissection and is associated with a better perioperative outcome and improved mid-term survival rate.

Aortic Dissection

Acute aortic dissection is a highly morbid condition with high mortality that requires emergent surgical evaluation and repair. The intraoperative management of acute aortic dissection requires the anesthesiologist to do far more than administer anesthesia and begins before the patient arrives at the operative theater. High-fidelity communication with the surgeon, knowledge of the surgical plan, knowledge of the anatomy of the dissection, and a nuanced understanding of aortic dissection pathophysiology are all critical aspects of anesthetic management.

A retrospective study of thoracic endovascular aortic repair timing in patients with uncomplicated type B dissection who have a smoking history

Objective

To determine the optimal timing of thoracic endovascular aortic repair (TEVAR) for patients with uncomplicated type B dissections who have a smoking history.

Methods

Data from 308 consecutive patients with uncomplicated type B dissections, who have a smoking history and onset-to-TEVAR time within 90 days, were analyzed. The patients were divided into two groups: Acute and subacute phases. Univariate and multivariate regression analyses were performed. Smooth curve fitting and threshold analysis were performed to characterize the relationship between the onset-to-TEVAR time and follow-up deaths.

Results

There were no significant differences between the two groups. Smooth curve fitting and threshold effect analysis showed that if early TEVAR was performed within 9.4 days from onset, there was better long-term survival and there was no significant difference after 9.4 days.

Conclusion

By studying the relationship between onset-to-TEVAR time and all-cause mortality, we found that early TEVAR may have a lower all-cause mortality rate during follow-up in uncomplicated type B dissection patients who have a smoking history and within 90 days from onset.

Progressive Aortic Enlargement in Medically Managed Acute SVS/STS Type B Aortic Dissections with Visceral Aortic Involvement

BACKGROUND

Aortic remodeling of the thoracic aorta has been studied in patients treated with medical or endovascular therapy for the treatment of acute aortic dissections; however, particular attention has not yet focused on identifying specific growth patterns and rates across all aortic zones. Additionally, previous studies have not delineated between dissections with and without visceral aortic involvement, and we hypothesize that these two cohorts may exhibit distinct differences. The aim of this study is to investigate aortic behavior over time in medically managed acute SVS/STS Type B dissections with visceral aortic involvement, and identify potential associations of subsequent aortic behavior with clinical outcomes.

METHODS

A single-center retrospective review was performed of all patients between 2010-2020 with acute SVS/STS Type B aortic dissections with visceral aortic involvement that were not surgically managed. Short-axis centerline measurements of the true/false lumen and total aortic diameter (TAD) were taken at standardized locations relative to aortic anatomy within each aortic zone, including non-dissected zones. Measurements were taken at the time of diagnosis and at six subsequent yearly intervals. Diameter changes over time were evaluated using repeated measures mixed models linear growth analysis. Aortic enlargement was classified by growth in TAD≥5mm in either the thoracic (Thoracic Segment Enlargement [TSE], Zone 0-4) or visceral segments (Visceral Segment Enlargement [VSE], Zone 5-9).

RESULTS

A total of 78 patients were identified with a median length of follow-up of 3.3 years (interquartile range [IQR]1.3-6.6 years). Follow-up past 5 years was seen in 31% of the cohort. For the entire cohort, mean thoracic growth in TAD was 2.0±2.0 mm/year and visceral growth in TAD 2.5±2.4 mm/year. TSE was observed in 65% of patients, with a median time until onset of 0.8 years (IQR 0.4-2.3 years). VSE was observed in 57% of the cohort, with a median time until onset of 1.6 years (IQR 0.9-3.3 years). Repeat measures mixed models linear growth analysis identified significant predictable linear growth in all aortic zones except for the non-dissected Zones 0-2. Odds for TSE are significantly increased in patients with known genetically triggered aortic conditions (GenTACs) (OR 2, 95% CI 1.8-4.5, p=0.044) and in cases where the dissection entry tear was in either Zone 1 or 2 (OR 4.8, 95% CI 1.2-8.4, p=0.044). In adjusted regression analysis, odds for intervention in the thoracic aorta were significantly increased in patients with rapid TSE in Zone 3 (OR 3.6 [1.1-8.4], p=0.045). Similarly, odds for intervention targeting the visceral aortic segment were significantly increased in patients with Zone 9 VSE (OR 9.3, 95% CI 1.1-13.3, p=0.014). Odds for 5-year all-cause mortality were significantly increased in cases with large thoracic aneurysms (OR 6.1, 95% CI 1.1-14.9, p=0.042).

CONCLUSIONS

Aortic enlargement was present in the majority of patients with medically managed acute SVS/STS Type B aortic dissections with visceral aortic involvement, with analysis demonstrating predictable linear growth in all dissected zones. Patients with aortic instability demonstrated higher gross changes in diameter in addition to higher yearly rates of change compared to all comers. Odds for enlargement were impacted by both patient demographic and anatomic dissection characteristics. Growth in Zone 3 and Zone 9 significantly increased odds for aortic intervention. Odds for 5-year mortality were significantly increased in the presence of large thoracic aneurysms. Results highlight risk of progressive degeneration beyond acute phase in SVS/STS Type B aortic dissections with visceral aortic involvement, with life-long surveillance remaining crucial in management of dissections.

The misnomer of uncomplicated type B aortic dissection

BACKGROUND

Acute type B aortic dissection (TBAD) is a rare condition that can be divided into complicated (CoTBAD) and uncomplicated (UnCoTBAD) based on certain presenting clinical and radiological features, with UnCoTBAD constituting the majority of TBAD cases. The classification of TBAD directly affects the treatment pathway taken, however, there remains confusion as to exactly what differentiates complicated from uncomplicated TBAD.

AIMS

The scope of this review is to delineate the literature defining the intervention parameters for UnCoTBAD.

METHODS

A comprehensive literature search was conducted using multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on intervention parameters and protocols for UnCoTBAD.

RESULTS

A TBAD without evidence of malperfusion or rupture might be classified as uncomplicated but there remains a subgroup who might exhibit high-risk features. Two clinical features representative of "high risk" are refractory pain and persistent hypertension. First-line treatment for CoTBAD is TEVAR, and whilst this has also proven its safety and effectiveness in UnCoTBAD, it is still being managed conservatively. However, TBAD is a dynamic pathology and a significant proportion of UnCoTBADs can progress to become complicated, thus necessitating more complex intervention. While the "high-risk" UnCoTBAD do benefit the most from TEVAR, yet, the defining parameters are still debatable as this benefit can be extended to a wider UnCoTBAD population.

CONCLUSION

Uncomplicated TBAD remains a misnomer as it is frequently representative of a complex ongoing disease process requiring very close monitoring in a critical care setting. A clear diagnostic pathway may improve decision making following a diagnosis of UnCoTBAD. Choice of treatment still predominantly depends on when an equilibrium might be reached where the risks of TEVAR outweigh the natural history of the dissection in both the short- and long-term.

[Chronic type B aortic dissection-what to do?]

BACKGROUND

Chronic type B aortic dissection requires optimal medical therapy. However, secondary complications like organ or extremity malperfusion or development of aneurysmal dilatation require interventional therapy.

OBJECTIVES

Presentation of different endovascular treatment options for complications of chronic type B aortic dissection.

MATERIALS AND METHODS

Analysis of current literature with regard to indications, techniques, results, and differential indications of interventional techniques for the treatment of chronic type B aortic dissection complications.

RESULTS

Endovascular implantation of an aortic stent graft is interventional standard therapy for treatment of aneurysmal dilatation of the aorta following type B dissection. Technical problems are the proximal and distal landing zones and the treatment of persistent flow in the false lumen.

CONCLUSION

Endovascular treatment of chronic complicated type B aortic dissection is increasingly used compared to open surgical treatment because not only are more complex stent grafts (fenestrated and branched devices) available but also because of newly developed techniques for effective occlusion of flow in the false lumen (e.g., candy plug).

Contemporary Unplanned Readmission Trends Following Management of Type B Aortic Dissection

Purpose

Methods

Results

Conclusion

False Lumen Flow Assessment by Magnetic Resonance Imaging and Long-Term Outcomes in Uncomplicated Aortic Dissection

BACKGROUND

Despite the absence of clinical complications after an acute aortic dissection (AD) with persistent patent false lumen (FL), a high risk for clinical events may persist.

OBJECTIVES

The aim of this study was to assess the natural evolution of noncomplicated AD and ascertain whether different FL flow patterns by magnetic resonance imaging (MRI) have independent prognostic value for AD-related events beyond established morphologic parameters.

METHODS

One hundred thirty-one consecutive patients, 78 with surgically treated type A dissections and 53 with medically treated type B dissections, were followed up prospectively after acute AD with persistent patent FL in the descending aorta. Maximum aortic diameter, true lumen compression, entry tear, and partial FL thrombosis by computed tomography were assessed. Systolic antegrade true lumen and FL flow volumes and diastolic antegrade and retrograde flows were analyzed by MRI during the first year after AD.

RESULTS

After a median follow-up period of 8.0 years (IQR: 4.6-10.9 years), 43 patients presented aorta-related events (25 died and 18 required endovascular treatment). FL systolic antegrade flow ≥30% with respect to total systolic antegrade flow and retrograde diastolic flow ≥80% with respect to total diastolic FL flow were predictors of aortic events. In multivariate analysis, aortic diameter >45 mm (HR: 2.91), type B dissection (HR: 2.44), and MRI flow pattern (HR: 16.87) were independent predictors of AD-related events.

CONCLUSIONS

High systolic antegrade flow volume in the FL with significant diastolic retrograde flow assessed by MRI and aortic diameter >45 mm identify patients with higher risk for complications in whom more aggressive management would be indicated.

Five-Year Results of Aortic Remodeling for Acute, Subacute, and Chronic Type B Aortic Dissection Following Endovascular Repair

Background

This study was performed to compare aortic remodeling and clinical outcomes in patients with acute, subacute, and chronic type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR).

Methods

We retrospectively examined 323 consecutive patients with acute (n = 129), subacute (n = 161), and chronic (n = 33) TBAD who underwent TEVAR from June 2013 to December 2016 in in multicenter institution. Patient demographics, clinical data, and imaging characteristics were recorded and compared among the three groups.

Results

The three groups had comparable baseline characteristics. Perioperative mortality rates were similar among the acute (2.3%), subacute (0.0%), and chronic (0.0%) groups (P = 0.34). Perioperative morbidity rates, including the rates of visceral and lower limb malperfusion and cerebral infraction, were also similar. The rate of perioperative endoleak was significantly higher in the chronic group (18.1%) than in the acute (3.9%) and subacute (3.7%) groups (P = 0.02). The mean follow-up duration was 78 ± 22 months (range, 36–101 months). The mortality rates were comparable among the three groups. The rates of reintervention and lower limb malperfusion were higher in the chronic group than in the acute and subacute groups. FL diameter reduction were more robust in the acute and subacute groups than in the chronic group.

Conclusion

Patients with acute, subacute, and chronic TBAD had different outcomes in this study. Patients with acute and subacute TBAD had fewer complications than those with chronic TBAD. Aortic remodeling after TEVAR was more favorable in patients with acute and subacute TBAD than in patients with chronic TBAD. TEVAR promotes more positive remodeling at the stent graft level than at the distal level of the aorta.

Evaluation of a Standardized Protocol for Medical Management of Uncomplicated Acute Type B Aortic Dissection

OBJECTIVES

The goals of medical management for uncomplicated acute type B aortic dissection are to prevent expansion of the false lumen and malperfusion syndrome. This is accomplished with antihypertensive agents, but medication selection and titration are typically provider dependent. Given the paucity of data on evidence-based management of this population, we hypothesized that a standardized type B aortic dissection medical management protocol would reduce resource utilization and costs, without compromising patient outcomes.

METHODS

A multidisciplinary team developed a goal-directed protocol to standardize the medical management of uncomplicated acute type B aortic dissection, with an emphasis on early initiation of oral medications, weaning of anti-hypertensive infusions and frequent assessment for de-escalation of care. Implementation was in April 2018. A retrospective review of acute type B aortic dissection patients presenting to our institution from April 2016- April 2020 was performed. Patients requiring aortic or peripheral intervention were excluded. Included patients were analyzed based on treatment before or after protocol implementation. Patient demographics, systolic blood pressure, presence of acute kidney injury at presentation, length of stay, cost metrics, and 30-day mortality were compared.

RESULTS

39 patients were included, 21 pre- and 18 post-protocol implementation. Baseline demographics, systolic blood pressure, and presence of acute kidney injury at presentation were similar between the groups. Post-protocol patients had shorter total (8.6 vs 5.5 days, p=.02) and intensive care unit (3.2 vs 1.8 days, p=.002) length of stay. The protocol was associated with significantly decreased total hospital ($38,928 vs $28,066, p=.04), total variable ($23,115 vs $15,627, p=0.02), and pharmacy ($5,094 vs $1,181, p<.001) costs, while inpatient care costs ($15,152 vs $11,467, p=.09) trended down. Post-protocol patients required fewer oral antihypertensive agents at discharge (3.8 vs 2.7, p=.005). No significant difference in 30-day mortality was observed.

CONCLUSIONS

A goal directed protocol reduces resource utilization and costs without compromising early mortality rates for patients with uncomplicated acute type B aortic dissection. Such a strategy may have broader application in medical management of acute aortic syndromes.

Time-dependent mechanical behaviour of the aortic chronic dissection flap

OBJECTIVES

The transition of aortic dissection from acute to chronic is poorly understood. We examined time-dependent mechanical behaviour and biochemical properties of chronic dissection tissues.

METHODS

Aorta samples were obtained from 14 patients with mixed aetiology who were undergoing elective surgery for chronic dissected aneurysms, ranging from 3 months to 15 years post-dissection. The tissue elastic modulus and tissue deformation following application of loading for 5 h were measured for the false lumen (FL), true lumen (TL) and flap (FP) tissues with a custom-indentation technique. Collagen, elastin and glycosaminoglycan levels were determined with established biochemical assays. Elastin fragmentation was graded from histological sections. The number of tissues characterized was as follows: FP (n = 10), TL (n = 5 for biomechanical testing, n = 8 for biochemical analysis, n = 8 for histological assessment) and FL (n = 4).

RESULTS

Tissues stiffness was highest in FP [59.8 (14.8) kPa] as compared with TL [50.7 (6.2) kPa] and FL [40.5 (4.7) kPa] (P = 0.023 and P = 0.006, respectively). FP [0.5 (0.08) mm] also exhibited reduced deformation relative to TL [0.7 (0.02) mm] and FL [0.9 (0.08) mm] (P = 0.003 and P = 0.006, respectively), lowest collagen concentration [FP: 40.1 (19.6) µg/mg, TL: 59.9 (19.5) µg/mg, P = 0.008; FL: 79.1 (32.0) µg/mg, P = 0.006] and the lowest collagen: elastin ratio [0.4 (0.1)] relative to the other tissues [TL; 0.6 (0.3), P = 0.006, FL; 1.5 (0.4); P = 0.003]. Significant elastin loss was evident in the FL-stained tissue sections whereas highly aligned, long fibres were visible in the FP and TL. A linear relationship was found between the stiffness, deformation and the time from the dissection event to surgical intervention for the FP. All data are presented as median (interquartile range).

CONCLUSIONS

FP exhibited reduced time-dependent deformation and distinct biochemical properties relative to TL and FL irrespective of connective tissue disorder or the anatomical region of the dissection.

The role of vascular smooth muscle cells in the development of aortic aneurysms and dissections

BACKGROUND

Aortic aneurysms (AA) are pathological dilations of the aorta, associated with an overall mortality rate up to 90% in case of rupture. In addition to dilation, the aortic layers can separate by a tear within the layers, defined as aortic dissections (AD). Vascular smooth muscle cells (vSMC) are the predominant cell type within the aortic wall and dysregulation of vSMC functions contributes to AA and AD development and progression. However, since the exact underlying mechanism is poorly understood, finding potential therapeutic targets for AA and AD is challenging and surgery remains the only treatment option.

METHODS

In this review, we summarize current knowledge about vSMC functions within the aortic wall and give an overview of how vSMC functions are altered in AA and AD pathogenesis, organized per anatomical location (abdominal or thoracic aorta).

RESULTS

Important functions of vSMC in healthy or diseased conditions are apoptosis, phenotypic switch, extracellular matrix regeneration and degradation, proliferation and contractility. Stressors within the aortic wall, including inflammatory cell infiltration and (epi)genetic changes, modulate vSMC functions and cause disturbance of processes within vSMC, such as changes in TGF-β signalling and regulatory RNA expression.

CONCLUSION

This review underscores a central role of vSMC dysfunction in abdominal and thoracic AA and AD development and progression. Further research focused on vSMC dysfunction in the aortic wall is necessary to find potential targets for noninvasive AA and AD treatment options.

Imaging and Surveillance of Chronic Aortic Dissection: A Scientific Statement From the American Heart Association

All patients surviving an acute aortic dissection require continued lifelong surveillance of their diseased aorta. Late complications, driven predominantly by chronic false lumen degeneration and aneurysm formation, often require surgical, endovascular, or hybrid interventions to treat or prevent aortic rupture. Imaging plays a central role in the medical decision-making of patients with chronic aortic dissection. Accurate aortic diameter measurements and rigorous, systematic documentation of diameter changes over time with different imaging equipment and modalities pose a range of practical challenges in these complex patients. Currently, no guidelines or recommendations for imaging surveillance in patients with chronic aortic dissection exist. In this document, we present state-of-the-art imaging and measurement techniques for patients with chronic aortic dissection and clarify the need for standardized measurements and reporting for lifelong surveillance. We also examine the emerging role of imaging and computer simulations to predict aortic false lumen degeneration, remodeling, and biomechanical failure from morphological and hemodynamic features. These insights may improve risk stratification, individualize contemporary treatment options, and potentially aid in the conception of novel treatment strategies in the future.

Racial Disparities in Presentation and Short-Term Outcomes in Patients with Acute Type B Aortic Dissection

OBJECTIVE

Racial disparities in cardiovascular risk factors and disease outcomes are well documented. A knowledge gap exists on the role health maintenance plays in the development and outcomes of type B aortic dissection (TBAD). This study aims to evaluate the comparative presentation and short-term outcomes of patients with TBAD across race.

METHODS

In this single center retrospective study, TBAD patients admitted to the intensive care unit (ICU) were identified from 2015 to 2020. Patients self-identified as Black (N= 57) and White (N=123) were included. Groups were compared on variables including demographics, socioeconomic, pre-event health maintenance. Socioeconomic disadvantage was quantified based on The Area Deprivation Index (ADI). Management strategies included nonoperative and surgical repair. Outcomes were 30-day mortality, length of stay (LOS), and Acute Physiology and Chronic Health Evaluation (APACHE II) score.

RESULTS

The study included 180 consecutive patients with TBAD. TBAD included complicated (n= 42) and uncomplicated (n=138), of which (n=79) had high risk features. Blacks were younger than Whites (58.9 vs 67.6; p< 0.01), more likely to have end stage renal disease (ESRD) (8.8% vs 0.8%; p= 0.01) and to present with anemia (10.5% vs 2.4%; p=0.03). TBAD anatomic features and management were similar in both groups. Surgical intervention during hospitalization was 40% and 46% in Blacks and Whites, respectively (p= 0.4). Black patients were more likely to be on 3 or more hypertension agents, (42.2% vs 16.4%; p= 0.005) and less likely to be adherent to prescribed agents (27.1% vs 6.7%; p<0.001). Black patients had fewer primary care physician (PCP) visits prior to TBAD event (p= 0.03) and more Emergency Department (ED) utilization prior to TBAD, (57.9% vs 26.9% ;p < 0.001). Black patients had higher ADI scores, 86.0 ± 14.6 vs 64.4 ± 21.3 (p < 0.001). Median [IQR] APACHE II score was the same in both Blacks and Whites, 9[6, 12] and 9[7, 13] respectively (p=0.7). Hospital median LOS (days) was identical in both groups 7 [5, 13]. Readmission was 24.5% in Blacks vs 15.5% in Whites (p=0.16) with a 30-day mortality similar in Blacks 7.0% vs 5.7% Whites (p= 0.7).

CONCLUSION

Black patients present younger with similar dissection morphology, rate of anatomic high risk features and APACHE II scores. Fewer PCP visits, greater ED utilization, and higher ADI suggest lower health maintenance in Black patients. White patients with TBAD were also highly deprived of health maintenance compared to the national percentile, indicating that TBAD is a disease that affects vulnerable populations regardless of race.

Differences in the Area of Proximal and Distal Entry Tears at CT Angiography Predict Long-term Clinical Outcomes in Aortic Dissection

Purpose

To identify entry tear variables that are related to adverse clinical events by using CT angiography (CTA) performed during the subacute phase of aortic dissection.

Materials and Methods

In this prospective study conducted from January 2000 to December 2013, participants with an aortic dissection with a patent false lumen and no comorbidities underwent CTA during the subacute phase. Participants were followed up for a survival analysis to assess the time to an adverse aortic event (AAE). The maximum aortic diameter (MAD), proximal and distal tear areas and difference between these areas, and partial false-lumen thrombosis were assessed by using Cox regression for adverse events.

Results

Seventy-two participants (mean age, 55 years ± 12 [standard deviation]; 55 men) were evaluated: 47 were surgically treated (type A aortic dissection) and 25 were medically treated (type B aortic dissection). Twenty-two participants had an AAE manifest during follow-up (9.22 years ± 5.78): There were 18 elective surgeries for aneurysmal degeneration, two emergent surgeries for acute aortic syndrome, and two aortic condition-related deaths. A categorical model composed of genetic aortic disease (GAD) (hazard ratio [HR], 3.4 [95% CI: 1.2, 9.9]; P = .02), MAD greater than 45 mm (HR, 6.1 [95% CI: 2.4, 15.8]; P < .001), and tear dominance (HR, 5.2 [95% CI: 2.1, 13]; P < .001), defined as an absolute tear area difference of greater than 1.2 cm², was used to stratify participants into three risk groups: low, without any risk factors (57% [41 of 72] and 7% [three of 41] had events); intermediate, with one risk factor (31% [22 of 72] and 50% [11 of 22] had events); and high, with two or more risk factors (13% [nine of 72] and 89% [eight of nine] had events; log rank P < .001).

Conclusion

Tear dominance demonstrated at CTA performed in the subacute phase of aortic dissection was related to long-term adverse events. Participants without GAD, dominant tears, or MAD greater than 45 mm had conditions that were safely managed with optimal medical treatment and imaging follow-up.Keywords: CT Angiography, Vascular, Aorta, Dissection Supplemental material is available for this article. © RSNA, 2021See also commentary by Fleischmann and Burris in this issue.

Obstructive Sleep Apnoea in Stanford Type B Aortic Dissection Is Associated With Multiple Imaging Signs Related to Late Aortic Events

Background: Obstructive sleep apnoea (OSA) is highly prevalent in patients with Stanford type B aortic dissection (TBAD). Few studies have evaluated the effects of OSA on vascular changes in TBAD patients. This study aimed to explore the effect of OSA on aortic morphological changes in TBAD patients and its relation to late aortic events (LAEs).

Methods: This case-control study included 143 TBAD patients. The diameters of different parts of the aorta were measured based on computed tomography angiography (CTA). According to the apnoea-hypopnoea index (AHI), OSA was classified as mild (5 ≤ AHI ≤ 15), moderate (15 < AHI ≤ 30), or severe (AHI > 30). The false lumen (FL) status was evaluated and classified as partially thrombosed, patent, or completely thrombosed.

Results: The OSA prevalence in TBAD patients was 64.3%, and image differences related to LAEs between TBAD patients with and without OSA included the maximum aortic diameter at onset (37.3 ± 3.9 vs. 40.3 ± 4.5 mm, p < 0.001), the FL diameter of the proximal descending thoracic aorta (16.0 ± 6.8 vs. 20.3 ± 4.7 mm, p < 0.001), and the proportion of the FL that was partially thrombosed (39.2 vs. 64.1%, p = 0.004). Additionally, in the multivariable analysis of patients with OSA, the risks of an aortic diameter ≥40 mm, a proximal descending aorta FL ≥ 22 mm and a partially thrombosed FL were 4.611 (95% CI: 1.796–11.838, p = 0.001), 2.544 (95% CI: 1.050–6.165, p = 0.039), and 2.565 (95% CI: 1.167–5.637, p = 0.019), respectively, after adjustment for confounding factors. Trend tests showed that the risks of an aortic diameter ≥40 mm and a partially thrombosed FL increased with increasing OSA severity.

Conclusions: TBAD patients with moderate to severe OSA have aortic dilatation in different parts of the aorta. OSA is an independent risk factor for multiple imaging signs related to LAEs, suggesting that OSA is an important factor affecting the prognosis of TBAD patients.

Proximal true lumen collapse in a chronic type B aortic dissection patient: A case report

BACKGROUND

In the context of aortic dissection, increasing pressure within the newly formed false lumen can result in the progressive compression of the true aortic channel. However, true lumen collapse in chronic type B aortic dissection (cTBAD) patients is rare, with few clinical or experimental studies to date having explored the causes of such collapse.

CASE SUMMARY

In the present report, we describe a rare case of true-lumen collapse in an 83-year-old patient diagnosed with cTBAD, and we discuss potential therapeutic interventions for such cases. Following thoracic endovascular aortic repair (TEVAR), computed tomography angiography revealed satisfactory stent-graft positioning, no endoleakage, true lumen enlargement, thrombus formation in the false lumen, and slight enlargement of the true lumen distal to the stent-graft. Computational hemodynamic analyses indicated that the wall shear stress and pressure within the false lumen were significantly reduced following TEVAR.

CONCLUSION

TEVAR treatment of cTBAD patients suffering from proximal true lumen collapse can facilitate some degree of effective remodeling.

Management of acute aortic syndromes from initial presentation to definitive treatment

BACKGROUND

Acute aortic syndromes comprise a spectrum of diseases including aortic dissection, intramural hematoma, and penetrating atherosclerotic ulcers. Early diagnosis, rapid intervention, and multidisciplinary team care are vital to efficiently manage time-sensitive aortic emergencies, mobilize appropriate resources, and optimize clinical outcomes.

OBJECTIVE

This comprehensive review outlines the multidisciplinary team approach from initial presentation to definitive interventional treatment and post-operative care.

DISCUSSION

Acute aortic syndromes can be life-threatening and require prompt diagnosis and aggressive initiation of blood pressure and pain control to prevent subsequent complications. Early time to diagnosis and intervention are associated with improved outcomes.

CONCLUSIONS

A multidisciplinary team can help promptly diagnose and manage aortic syndromes.