Development and Validation of a User Friendly Morphology Grading System (PATENT) Predicting Aortic Remodelling After Thoracic Endovascular Aortic Repair in High Risk Uncomplicated Type B Aortic Dissection

OBJECTIVE

This study aimed to create a morphology grading system, solely based on 2D images from computed tomography angiography, to predict negative aortic remodelling (NAR) for patients with high risk uncomplicated type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR).

METHODS

This single centre retrospective cohort study extracted and analysed consecutive patients diagnosed with high risk uncomplicated TBAD. Negative aortic remodelling was defined as an increase in the false lumen or total aortic diameter, or decrease in the true lumen diameter. The multivariable Cox regression model identified risk factors and a prediction model was created for two year freedom from NAR. A three category grading system, in which patients were classified into low, medium, and high risk groups, was further developed and internally validated.

RESULTS

Of 351 patients included, 99 (28%) developed NAR. The median age was 52 years (interquartile range 45, 62 years) and 56 (16%) were female. The rate of two year freedom from NAR was 71% (95% CI 65 - 77%). After the multivariable Cox regression analysis, Patent false lumen, Aberrant right subclavian artery, Taper ratio, abdominal circumferential Extent, coeliac artery or reNal artery involved, and four channel dissection (Three false lumens) remained independent predictors and were included in the PATENT grading system. The risk score was statistically significantly associated with NAR (HR 1.21; 95% CI 1.14 - 1.29; p < .001). The medium and high risk groups demonstrated a higher rate of NAR (medium risk, HR 2.82; 95% CI 1.57 - 5.01; p = .001; high risk, HR 4.39; 95% CI 2.58 - 7.48; p < .001). The grading system was characterised by robust discrimination with Harrell's C index of 0.68 (95% CI 0.63 - 0.75).

CONCLUSION

The PATENT grading system was characterised by good discrimination and calibration, which may serve as a clinician friendly tool to aid risk stratification for TBAD patients after TEVAR.

Aortic Remodeling After Thoracic Endovascular Aortic Repair for Nonacute Uncomplicated Type B Aortic Dissection

BACKGROUND

Entry closure with thoracic endovascular aortic repair (TEVAR) for Stanford type B aortic dissection (TBAD) results in aortic remodeling recently. This study aimed to evaluate the relationship between aortic diameter or timing of surgical intervention from onset and remodeling after TEVAR for uncomplicated nonacute TBAD.

METHODS

Between April 2014 and December 2021, 83 consecutive patients underwent TEVAR for TBAD at our center. Forty patients with subacute and chronic uncomplicated TBADs with a patent false lumen, who could be followed up for at least 6 months, were included in this study. Indications for TEVAR included aortic diameter enlargement and preemptive treatment to prevent future aneurysmal changes in patients at risk of aortic diameter enlargement. Aortic remodeling was accessed, and data between the remodeling and nonremodeling groups were compared.

RESULTS

The technical success rate was 97.5%, with a type Ia endoleak remaining in 1 patient. No operative or in-hospital mortality occurred. Paraparesis occurred in only 1 patient (2.5%). Follow-up was completed at a median of 53.5 months. Late death occurred in 3 cases, but there were no aortic-related deaths. Late aortic remodeling was achieved in 22 patients (55%). The preoperative maximum aortic diameter (PMAD) in the thoracic aortic region was 51.5 mm in the nonremodeling group, significantly larger than 42.5 mm in the remodeling group (P < 0.0001). The cutoff value of the PMAD for predicting aortic remodeling was 45 mm (area under the curve, 0.917; P = 0.028). The remodeling group had an earlier time from onset to intervention than the nonremodeling group, with a cutoff value of 6.3 months (area under the curve, 0.743; P = 0.021).

CONCLUSIONS

TEVAR for nonacute uncomplicated TBAD resulted in a late aortic remodeling rate of 55%. This study suggested that a PMAD of >45 mm or a period >6.3 months between dissection onset and surgery hinders aortic remodeling after TEVAR.

Clinical Outcomes and Factors Associated With Aortic Shrinkage After Thoracic Endovascular Aortic Repair for Aneurysmal Chronic Aortic Dissection

PURPOSE

The effectiveness of thoracic endovascular aortic repair (TEVAR) for chronic aortic dissection (AD) with aneurysmal degeneration remains controversial. We retrospectively investigated clinical outcomes and assessed predictors of aortic shrinkage after TEVAR for chronic aneurysmal AD.

MATERIALS AND METHODS

Between January 2010 and December 2021, 70 patients with double-barrel-type chronic AD were enrolled. Major intimal tears in thoracic aorta were covered by stent graft. Early and late clinical outcomes, and diameter change of downstream aorta during follow-up period were reviewed. Subsequently, factors associated with aortic shrinkage were assessed by logistic regression analysis.

RESULTS

Mean age was 63 (interquartile range [IQR]: 54-68) years, 54 (80%) men, median duration from AD onset was 4 (IQR: 1-10) years, and maximum aortic diameter was 53 (IQR: 49-58) mm. Supra-aortic debranching procedure was required in 57 (81%) patients. Early aorta-related death occurred in 2 (3%) patients. Both stroke and spinal cord ischemia occurred in 1 (2%) patient. Five-year freedom rates from aorta-related death and reintervention were 96% and 51%, respectively. Sixty-four patients underwent follow-up computed tomography (84%) 1 year after TEVAR, with 33 (52%) achieving aortic shrinkage. In multivariable analysis, duration from AD onset (per year) (odds ratio [OR]: 0.82, 0.70-0.97; p=0.017) and maximum aortic-diameter ratio between aortic arch and descending aorta (per 0.1) (morphologic index; OR: 1.34, 1.04-1.74; p=0.023) were independent aortic shrinkage predictors.

CONCLUSIONS

Thoracic endovascular aortic repair for chronic AD with aneurysmal degeneration achieved satisfactory survival outcomes, but with a considerable reintervention rate. Duration from AD onset and preoperative aortic morphology could affect post-TEVAR aortic shrinkage. Earlier intervention could lead to better aortic shrinkage.

CLINICAL IMPACT

Thoracic endovascular aortic repair for chronic aortic dissection with aneurysmal degeneration showed low incidence of early and late aorta-related death. By contrast, aortic shrinkage rate was low with high incidence of reintervention to the residual downstream aorta. According to the assessment of preoperative variables, chronicity and aortic morphology could predict postoperative aortic shrinkage.

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

BACKGROUND

There is emerging evidence to support pre-emptive thoracic endovascular aortic repair (TEVAR) intervention for uncomplicated type B aortic dissection (unTBAD). Pre-emptive intervention would be particularly beneficial in patients that have a higher baseline risk of progressing to complicated TBAD (coTBAD). There remain debate on the optimal clinical, laboratory, morphological, and radiological parameters, which would identify the highest-risk patients that would benefit most from pre-emptive TEVAR.

AIM

This review summarizes evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients.

METHODS

A comprehensive literature search was carried out on multiple electronic databases including PubMed, EMBASE, Ovid, and Scopus to collate all research evidence on the clinical, laboratory, and morphological parameters that increase the risk profiles of unTBAD patients RESULTS: At present, there are no clear clinical guidelines using risk-stratification to inform the selection of unTBAD patients for TEVAR. However, there are noticeable literature trends that can assist with the identification of the most at-risk unTBAD patients. Patients are at particular risk when they have refractory pain and/or hypertension, elevated C-reactive protein (CRP), larger aortic diameter, and larger entry tears. These risks should be considered alongside factors that increase the procedural risk of TEVAR to create a well-balanced approach. Advances in biomarkers and imaging are likely to identify more pertinent parameters in the future to optimize the development of balanced, risk-stratified treatment protocols.

CONCLUSION

There are a variety of risk profiling parameters that can be used to identify the high-risk unTBAD patient, with novel biomarkers and imaging parameters emerging. Longer-term evidence verifying these parameters would be ideal. Further randomized controlled trials and multicentre registry analyses are also warranted to guide risk-stratified selection protocols.

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.

Mid- and long-term outcomes of thoracic endovascular aortic repair in acute and subacute uncomplicated type B aortic dissection

BACKGROUND

Uncomplicated type B aortic dissection (un-TBAD) has been managed conservatively with medical therapy to control the heart rate and blood pressure to limit disease progression, in addition to radiological follow-up. However, several trials and observational studies have investigated the use of thoracic endovascular aortic repair (TEVAR) in un-TBAD and suggested that TEVAR provides a survival benefit over medical therapy. Outcomes of TEVAR have also been linked with the timing of intervention.

AIMS

The scope of this review is to collate and summarize all the evidence in the literature on the mid- and long-term outcomes of TEVAR in un-TBAD, confirming its superiority. We also aimed to investigate the relationship between the timing of TEVAR intervention and results.

METHODS

We carried out a comprehensive literature search on multiple electronic databases including PubMed, Scopus, and EMBASE to collate and summarize all research evidence on the mid- and long-term outcomes of TEVAR in un-TBAD, as well as its relationship with intervention timing.

RESULTS

TEVAR has proven to be a safe and effective tool in un-TBAD, offering superior mid- and long-term outcomes including all-cause and aorta-related mortality, aortic-specific adverse events, aortic remodeling, and need for reintervention. Additionally, performing TEVAR during the subacute phase of dissection seems to yield optimal results.

CONCLUSION

The evidence demonstrating a survival advantage in favor TEVAR over medical therapy in un-TBAD means that with further research, particular trials and observational studies, TEVAR could become the gold-standard treatment option for un-TBAD patients.

Thoracic endovascular repair of chronic type B aortic dissection: a systematic review

BACKGROUND

At present, the optimal management strategy for chronic type B aortic dissection (CTBAD) remains unknown, as equipoise remains regarding medical management versus endovascular treatment versus open surgery. However, the results over recent years of thoracic endovascular aortic repair (TEVAR) in CTBAD appear promising. The aim of this systematic review was to provide a comprehensive analysis of the available data reporting outcomes and survival rates for TEVAR in CTBAD.

METHODS

Electronic searches of six databases were performed from inception to April 2021. All studies reporting outcomes, specifically 30-day mortality rates, for endovascular repair of CTBAD were identified. Relevant data were extracted, and a random-effects meta-analysis of proportions or means was performed to aggregate the data. Survival data were pooled using data derived from original Kaplan-Meier curves, which allows reconstruction of individual patient data.

RESULTS

Forty-eight studies with 2,641 patients were identified. Early (<30 days) all-cause and aortic-related mortality rates were low at 1.6% and 0.5%, respectively. Incidence of retrograde type A dissection in the post-operative period was only 1.4%. There were also low rates of cerebrovascular accidents and spinal cord injury (1.1% and 0.9%, respectively). Late follow-up all-cause mortality was 8.0%, however, late aortic-related mortality was only 2.4%. Reintervention rates were 10.1% for endovascular and 6.7% for surgical reintervention. Pooled rates of overall survival at 1-, 3-, 5- and 10-year were 91.5%, 84.7%, 77.7% and 56.3%, respectively.

CONCLUSIONS

The significant heterogeneity in the available evidence and absence of consensus reporting standards are important considerations and concern when interpreting the data. Evaluation of the evidence suggests that TEVAR for CTBAD is a safe procedure with low rates of complications. However, the optimal treatment strategy for CTBAD remains debatable and requires further research. Evidence from high-quality registries and clinical trials are required to address these challenges.

TEVAR for complicated and uncomplicated type B aortic dissection-Systematic review and meta-analysis

BACKGROUND

Type B aortic dissection (TBAD), is defined as a dissection involving the aorta distal to left subclavian artery with the ascending aorta and the aortic arch not affected. TBAD is classified due to the time frame and presence of complications. Complicated TBAD (co-TBAD) patients have a greater mortality rate than uncomplicated TBAD (un-TBAD) and thoracic endovascular aortic repair (TEVAR) is considered the gold-standard intervention for these clinical challenges.

METHODS

We undertook a systematic review of the literature regarding TEVAR intervention in co-TBAD and un-TBAD. A comprehensive search was undertaken across four major databases and was evaluated and assessed until June 2020.

RESULTS

A total of 16,104 patients were included in the study (7772 patients co-TBAD and 8352 un-TBAD). A significantly higher proportion of comorbidities were seen in co-TBAD patients compared with un-TBAD. Acute dissection was more frequent in the co-TBAD group (73.55% vs. 66.91%), while chronic dissection was more common in un-TBAD patients (33.8% vs. 70.73%). Postprocedure stroke was higher in co-TBAD (5.85% vs. 3.92%; p < .01), while postprocedural renal failure was higher in un-TBAD patients (7.23 vs. 11.38%; p < .01). No difference was observed in in-hospital mortality however the 30 days mortality was higher in the co-TBAD group. One-year survival was higher in the uncomplicated group but this difference was not observed in the 5-year survival.

CONCLUSION

In our analysis we can appreciate that despite significantly higher comorbidities in the co-TBAD cohort, there was no difference in in-hospital mortality between the two groups and the 5-year survival did not have any difference.

Intercostal artery embolization to induce false lumen thrombosis in type B aortic dissection

Persistent false lumen flow is common after thoracic endovascular aortic repair of type B aortic dissection and may contribute to continued aortic aneurysmal degeneration. We report an innovative technique of intercostal artery embolization within the false lumen for a patient who had incomplete false lumen thrombosis and progressive aortic enlargement after thoracic endovascular aortic repair of chronic type B aortic dissection. Technical success was facilitated by use of on-table cone beam computed tomography angiography, virtual vessel marking, and modern endovascular tools. The patient had no complications from the procedure. Postoperative imaging demonstrated complete thoracic false lumen thrombosis and favorable aortic remodeling with reduction in maximal aortic diameter.

Landing Zone Remodelling after Endovascular Repair of Dissected Descending Aorta

OBJECTIVE

The aim of this study was to determine geometric changes in the proximal and distal aortic landing zones after thoracic endovascular aortic repair (TEVAR) for acute descending aortic dissection.

METHODS

This was a retrospective analysis of clinical and radiological data. Included are patients who underwent TEVAR for acute descending aortic dissection between 2004 and 2018. Analysed are the proximal and distal landing zones' initial geometries and their change at follow up. Median follow up time was 2.3 (first quartile 0.9, third quartile 4.5) years.

RESULTS

One hundred and one patients were included (93 type B and 8 non-A non-B dissections, aged 65 (57, 74) years old, and 29% female). Dissection extended down to the abdominal aorta in 69% patients. The proximal landing zone was non-dissected in 92 patients. The diameters of non-dissected proximal landing zones increased by 3 (-1, 5; p < .001) mm at follow up. The distal landing zone was dissected in 84% of patients. The diameters of dissected distal landing zones had increased at follow up by 7 (3, 12) mm and 4 (1, 10; both p < .001) mm measured in true lumen and total aorta, respectively, observed one year after TEVAR. Stent grafts reached their nominal diameter at follow up in 22% and 17% of proximal and distal landing zones, respectively. There were seven proximal and 10 distal stent graft induced new entries at follow up. Aortic re-intervention was necessary in 23 patients entailing 19 TEVAR extensions and four open aortic repairs.

CONCLUSION

The distal landing zone in patients undergoing TEVAR for descending aortic dissection is frequently dissected and is associated with the risk of d-SINE at follow up and the need for re-interventions after TEVAR - factors that emphasise the importance of long term follow up.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Aortic remodelling after thoracic endovascular aortic repair for acute and subacute type B aortic dissection

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) in the current era has gained widespread acceptance as the modality of choice for the treatment of complicated aortic dissection (AD). However, reports on clinical results of TEVAR treatment of AD patients are mainly comparisons and analyses of results between patients in the acute and chronic phases, few reports have described the postoperative aortic remodelling of patients with subacute AD after TEVAR. The aim of this study was to investigate aortic remodelling after TEVAR in acute and subacute Stanford type B AD patients.

METHODS

The clinical data of 38 Stanford type B AD patients who received TEVAR treatment in our hospital between July 2012 and December 2017 were retrospectively analysed. The maximum diameters of the aorta, the mean diameters of the true lumens (TLs) and the false lumens (FLs) of the aorta in the dissection range before and after TEVAR treatment were measured. All diameters between different groups or in the same group before and after therapy were compared using nonparametric tests. Count data were examined using the χ² test.

RESULTS

The 38 patients were 31.0-82.0 years old with a mean age of 57.0±11.0 years, including 31 men and 7 women, with 22 patients in the acute phase and 16 patients in the subacute phase. Among the 38 patients included in this study, 7 (18.4%) patients had endoleaks after treatment. No perioperative deaths occurred. Analyses of computed tomography angiography measurement results showed that the baseline maximum diameters of the aorta, TLs and FLs before TEVAR between the acute and subacute groups were not significantly different (P=0.193, P=0.301 and P=0.067, respectively). After TEVAR treatment, the maximum diameters of the aorta and the diameters of the FLs were different between the two groups (P=0.005 and P=0.012), but the diameters of the TLs were not (P=0.069). The diameters of the TLs increased, and those of FLs decreased significantly in the acute and subacute groups after TEVAR (P<0.001, P<0.001, P<0.001 and P=0.007, respectively); the maximum diameters of the aorta decreased significantly in the acute group (P<0.001), but they did not change obviously in the subacute group (P=0.121).

CONCLUSIONS

TEVAR offers satisfactory results for the treatment of type B AD. Acute AD may be associated with better aortic remodelling compared to subacute AD after TEVAR.

Conservative management versus endovascular or open surgery in the spectrum of type B aortic dissection

Background

Type B aortic dissection is a life-threatening acute aortic condition often with acute ischemic signs or symptoms. With initial management focusing on alleviating malperfusion and pain, and avoiding propagation of dissection or rupture both systolic blood and pulse pressure should be reduced initially by an aggressive medical approach. In the setting of persistent signs of complications endovascular strategies have replaced open surgery and led to a fourfold increase in early survival and better long-term outcomes.

Methods

An electronic health database search was performed on articles published between January 2006 and July 2017. Publications were included in this review if (I) the index aortic pathology was type B aortic (distal) dissection; (II) when medical management, open surgical replacement or thoracic endovascular aortic repair were among those options; (III) when at least one of all basic outcome criteria such as survival, spinal cord ischemia and cerebrovascular accident was reported; (IV) when ≥15 serial patients were included. A total of 62 studies were eligible and analysed.

Results

Our manuscript has summarized data collected over 12 years on management specific outcomes in the setting of distal aortic dissection and provides an up-to-date interpretation of the published evidence. For complicated cases, treated acutely, the 30-day or in-hospital mortality was 7.3% when managed by endovascular means, whereas the pooled rate for 30-day or in-hospital mortality was 19.0% when subjected to open repair. For acute uncomplicated type B dissection usually treated with blood pressure lowering medications, the pooled 30-day or in-hospital mortality rate was 2.4%. Survival rates at 5 years averaged at 60% (40% mortality). Freedom from any aortic event ranged from 34.0% to 83.9%, underlining an inherent risk of progression and late complications. For chronic complicated type B dissection, the rates of stroke, paraplegia and operative mortality following endovascular repair ranged from 5% to 13%, 2% to 13% and 2 to 13%, respectively, while 5-year survival rates after open repair ranged from 60% to 90%. In chronic uncomplicated type B dissection almost 90% of patients survive initial hospitalization and were subjected to medical management with a 5-year survival of 50-80%. However, up to 20-55% of medically treated patients develop aneurysmal degeneration after 5 years with an unknown risk of rupture.

Conclusions

Currently, the less invasive strategy of endovascular repair (as compared to open surgery) provides improved 30-day or in-hospital survival in the setting of complicated acute type B aortic dissection and may seek broad application. Open surgical aortic reconstruction should be left to experienced aortic centres if endovascular management is not an option.

A novel anatomic severity grading score for acute Type B aortic dissections and correlation to aortic reinterventions after thoracic endovascular aortic repair

Background

We introduce a novel preoperative anatomic severity grading system for acute type B aortic dissections and validate the system in a cohort of patients who underwent thoracic endovascular aortic repair.

Methods

We identified a cohort of patients who received thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection from 2008 to 2014. We developed an anatomic severity grading score (ASG) to measure attributes of aortic anatomy that we hypothesized may affect difficulty or durability of repair. Measurements were made using computed tomography angiography images and based on hypothesized severity, giving a potential score range of 0-38.

Results

We analyzed the computed tomography angiography images on a cohort of 30 patients with acute type B aortic dissection who underwent TEVAR. We created an area under the receiver operating characteristic curve (AUROC) using anatomic severity grading to predict aortic-related reinterventions. The AUROC was 0.72 (95% CI 0.39 to 1.1). Guided by the AUROC, we divided patients into two groups: a low-score group with anatomic severity grading scores <23 (n = 22), and a high-score group with scores ≥23 (n = 8). With this cutoff, anatomic severity grading exhibited 80% sensitivity and 84% specificity in predicting aortic-related reinterventions, with reinterventions in 50% of high-score patients and 4.5% of low-score patients (P = 0.011). The high score group also had significantly greater blood loss (200 vs 100 mL, P = 0.038), fluoroscopy time (36.0 vs 16.6 min; P = 0.022), and a trend for increased procedure time (164 vs 95 min; P = 0.083) than the low-risk group. Kaplan-Meier analysis revealed that the high-score group had a significantly decreased freedom from aortic-related reinterventions than the low-score group (38% vs 100% at 12-month followup; log rank P = 0.001).

Conclusions

A preoperative anatomic severity grading score for acute type B aortic dissections consists of analysis of the proximal landing zone, curvature and tortuosity of the aorta, dissection anatomy, aortic branch vessel anatomy, and supraceliac aorta anatomy. Anatomic severity grading scores ≤23 are an excellent predictor of aortic-related reinterventions.

Contemporary Management Strategies for Chronic Type B Aortic Dissections: A Systematic Review

Background

Currently, the optimal management strategy for chronic type B aortic dissections (CBAD) is unknown. Therefore, we systematically reviewed the literature to compare results of open surgical repair (OSR), standard thoracic endovascular aortic repair (TEVAR) or branched and fenestrated TEVAR (BEVAR/FEVAR) for CBAD.

Methods

EMBASE and MEDLINE databases were searched for eligible studies between January 2000 and October 2015. Studies describing outcomes of OSR, TEVAR, B/FEVAR, or all, for CBAD patients initially treated with medical therapy, were included. Primary endpoints were early mortality, and one-year and five-year survival. Secondary endpoints included occurrence of complications. Furthermore, a Time until Treatment Equipoise (TUTE) graph was constructed.

Results

Thirty-five articles were selected for systematic review. A total of 1081 OSR patients, 1397 TEVAR patients and 61 B/FEVAR patients were identified. Early mortality ranged from 5.6% to 21.0% for OSR, 0.0% to 13.7% for TEVAR, and 0.0% to 9.7% for B/FEVAR. For OSR, one-year and five-year survival ranged 72.0%-92.0% and 53.0%-86.7%, respectively. For TEVAR, one-year survival was 82.9%-100.0% and five-year survival 70.0%-88.9%. For B/FEVAR only one-year survival was available, ranging between 76.4% and 100.0%. Most common postoperative complications included stroke (OSR 0.0%-13.3%, TEVAR 0.0%-11.8%), spinal cord ischemia (OSR 0.0%-16.4%, TEVAR 0.0%-12.5%, B/FEVAR 0.0%-12.9%) and acute renal failure (OSR 0.0%-33.3%, TEVAR 0.0%-34.4%, B/FEVAR 0.0%-3.2%). Most common long-term complications after OSR included aneurysm formation (5.8%-20.0%) and new type A dissection (1.7–2.2%). Early complications after TEVAR included retrograde dissection (0.0%-7.1%), malperfusion (1.3%–9.4%), cardiac complications (0.0%–5.9%) and rupture (0.5%–5.0%). Most common long-term complications after TEVAR were rupture (0.5%–7.1%), endoleaks (0.0%–15.8%) and cardiac complications (5.9%-7.1%). No short-term aortic rupture or malperfusion was observed after B/FEVAR. Long-term complications included malperfusion (6.5%) and endoleaks (0.0%-66.7%). Reintervention rates after OSR, TEVAR and B/FEVAR were 5.8%-29.0%, 4.3%-47.4% and 0.0%-53.3%, respectively. TUTE for OSR was 2.7 years, for TEVAR 9.9 months and for B/FEVAR 10.3 months.

Conclusion

We found a limited early survival benefit of standard TEVAR over OSR for CBAD. Complication rates after TEVAR are higher, but complications after OSR are usually more serious. Initial experiences with B/FEVAR show its feasibility, but long-term results are needed to compare it to OSR and standard TEVAR. We conclude that optimal treatment of CBAD remains debatable and merits a patient specific decision. TUTE seems a feasible and useful tool to better understand management outcomes of CBAD.

Thoracic endovascular aortic repair for complicated chronic type B aortic dissection in a patient on hemodialysis with recurrent ischemic colitis

We present a successful case of thoracic endovascular aortic repair (TEVAR) for chronic Stanford type B aortic dissection (B-AD) with recurrent ischemic colitis. The patient was a 56-year-old woman with abdominal pain as the main complaint who had two operations previously: the total arch replacement 8 years ago and the Bentall 7 years ago for acute Stanford type A aortic dissection. Her abdominal pain worsened as her blood pressure became low during her hemodialysis treatment. An enhanced computed tomography scan was performed on the patient and showed chronic B-AD that occurred from the distal anastomotic part of the total arch graft to the bilateral common iliac arteries. The celiac artery and superior mesenteric artery (SMA) arose from the true lumen, and these were compressed by the expanded false lumen. Her complicated chronic B-AD was treated with the Zenith Dissection Endovascular System, and its procedure was performed as her proximal entry tear was covered by a proximal tapered Zenith TX2 stent graft, supplemented by a noncovered aortic stent extending across both renal arteries, the SMA, and the celiac artery. Seven days after this operation, enhanced computed tomography showed that the patient's true lumen was expanded and her blood flow to the true lumen and SMA was improved. On the other hand, her false lumen tended to be thrombosed. Consequently, she was discharged 10 days after the operation without any postoperative complications as she had no abdominal complaints even though she underwent hemodialysis three times per week after the operation. We believe that TEVAR supplemented by a noncovered aortic stent is an effective treatment, even for highly chronic B-AD in dialysis patients.

Biomechanical Changes After Thoracic Endovascular Aortic Repair in Type B Dissection

Thoracic endovascular aortic repair (TEVAR) has evolved into an established treatment option for type B aortic dissection (TBAD) since it was first introduced 2 decades ago. Morbidity and mortality have decreased due to the minimally invasive character of TEVAR, with adequate stabilization of the dissection, restoration of true lumen perfusion, and subsequent positive aortic remodeling. However, several studies have reported severe setbacks of this technique. Indeed, little is known about the biomechanical behavior of implanted thoracic stent-grafts and the impact on the vascular system. This study sought to systematically review the performance and behavior of implanted thoracic stent-grafts and related biomechanical aortic changes in TBAD patients in order to update current knowledge and future perspectives.

Type B Aortic Dissection: A Review of Prognostic Factors and Meta-analysis of Treatment Options

According to international guidelines, stable patients with uncomplicated Type B aortic dissection (TBAD) should receive optimal medical treatment. Despite adequate antihypertensive therapy, the long-term prognosis of these patients is characterized by a significant aortic aneurysm formation in 25-30% within four years, and survival rates from 50 to 80% at five years and 30 to 60% at 10 years. In a prospective randomized trial, preemptive thoracic endovascular aortic repair (TEVAR) in patients with chronic uncomplicated TBAD was associated with an excess early mortality (due to periprocedural hazards), but the procedure showed its benefit in prevention of aortic-specific mortality at five years of follow-up. However, preemptive TEVAR may not be the treatment of choice in all patients with uncomplicated TBAD because of the inherent periprocedural complications like stroke, paraparesis, and death, as well as stent graft-induced complications (i.e., retrograde dissection or endoleaks). Thus, the TEVAR-related deaths and complications (especially paraplegia and stroke) raise concerns that moderate the better survival with TEVAR at five years. By timely identification of those patients prone for developing complications, early intervention, preferably in the subacute or early chronic phase, may improve the overall long-term outcome for these patients. Therefore, early detectable and reliable prognostic factors for adverse events are essential to stratify patients who can be treated medically and those who will benefit from rigorous follow-up and, in the long-term, from timely, or even prophylactic, TEVAR. Several studies have identified prognostic factors in TBAD such as aortic diameter, partial false lumen thrombosis, false lumen thickness, and location of the primary entry tear. Combining these clinical and radiological predictors may be essential to implement a patient-specific approach designed to intervene only in those patients who are at high risk of developing complications to improve the long-term outcomes of patients with uncomplicated Type B aortic dissection.