A systematic review of aortic remodeling after endovascular repair of type B aortic dissection: methods and outcomes

Automatic Segmentation of Type A Aortic Dissection on Computed Tomography Images Using Deep Learning Approach

PURPOSE

Type A aortic dissection (TAAD) is a life-threatening aortic disease. The tear involves the ascending aorta and progresses into the separation of the layers of the aortic wall and the occurrence of a false lumen. Accurate segmentation of TAAD could provide assistance for disease assessment and guidance for clinical treatment.

METHODS

This study applied nnU-Net, a state-of-the-art biomedical segmentation network architecture, to segment contrast-enhanced CT images and quantify the morphological features for TAAD. CT datasets were acquired from 24 patients with TAAD. Manual segmentation and annotation of the CT images was used as the ground-truth. Two-dimensional (2D) nnU-Net and three-dimensional (3D) nnU-Net architectures with Dice- and cross entropy-based loss functions were utilized to segment the true lumen (TL), false lumen (FL), and intimal flap on the images. Four-fold cross validation was performed to evaluate the performance of the two nnU-Net architectures. Six metrics, including accuracy, precision, recall, Intersection of Union, Dice similarity coefficient (DSC), and Hausdorff distance, were calculated to evaluate the performance of the 2D and 3D nnU-Net algorithms in TAAD datasets. Aortic morphological features from both 2D and 3D nnU-Net algorithms were quantified based on the segmented results and compared.

RESULTS

Overall, 3D nnU-Net architectures had better performance in TAAD CT datasets, with TL and FL segmentation accuracy up to 99.9%. The DSCs of TLs and FLs based on the 3D nnU-Net were 88.42% and 87.10%. For the aortic TL and FL diameters, the FL area calculated from the segmentation results of the 3D nnU-Net architecture had smaller relative errors (3.89-6.80%), compared to the 2D nnU-Net architecture (relative errors: 4.35-9.48%).

CONCLUSIONS

The nnU-Net architectures may serve as a basis for automatic segmentation and quantification of TAAD, which could aid in rapid diagnosis, surgical planning, and subsequent biomechanical simulation of the aorta.

Optimal Timing of Pre-emptive Thoracic Endovascular Aortic Repair in Uncomplicated Type B Aortic Dissection: A Network Meta-Analysis

BACKGROUND

This network meta-analysis compares outcomes of optimal medical therapy (OMT) and pre-emptive thoracic endovascular aortic repair (TEVAR) for uncomplicated type B aortic dissection at different phases of chronicity.

METHODS

MEDLINE and EMBASE were searched through November 2023. Pooled short-term outcomes (short-term mortality, perioperative complications) and long-term outcomes (all-cause mortality, aortic-related mortality, aortic re-intervention rates) were calculated.

RESULTS

Systematic review identified 17 studies (2 randomized controlled trials, 3 propensity score matching, and 2 inverse probability weighting). Subacute-phase intervention had lower short-term mortality than the acute-phase (hazard ratio [HR] [95% confidence interval [CI]]=0.60 [0.38-0.94], p=0.027). No significant differences were observed in aortic rupture and paraplegia. Acute-phase TEVAR had a higher stroke incidence than subacute-phase intervention (HR [95% CI]=2.63 [1.36-5.09], p=0.042), chronic (HR [95% CI]=2.5 [1.03-6.2], p=0.043), and OMT (HR [95% CI]=1.57 [1.12-2.18], p=0.008). Acute-phase TEVAR had higher long-term all-cause mortality than subacute-phase intervention (HR [95% CI]=1.34 [1.03-1.74], p=0.03). Optimal medical therapy had elevated long-term all-cause mortality compared with subacute-phase TEVAR (HR [95% CI]=1.67 [1.25-2.33], p<0.001) and increased long-term aortic-related mortality vs acute-phase (HR [95% CI]=2.08 [1.31-3.31], p=0.002) and subacute-phase (HR [95% CI]=2.6 [1.62-4.18], p<0.01) interventions. No significant differences were observed in aortic re-intervention rates.

CONCLUSIONS

Pre-emptive TEVAR may offer lower all-cause mortality and aortic-related mortality than OMT. Considering lower short-term mortality, perioperative stroke rate, and long-term mortality, our findings support pre-emptive TEVAR during the subacute phase.

CLINICAL IMPACT

The optimal timing of pre-emptive thoracic endovascular aortic repair (TEVAR) for uncomplicated type B aortic dissection remains uncertain. This network meta-analysis suggests that the subacute phase (14-90 days from symptom onset) emerges as the optimal timing for pre-emptive TEVAR. This window is associated with lower rates of short-term complications and higher long-term survival rates compared with alternative strategies.

STABILISE (Stent-Assisted Balloon-Induced Intimal Disruption and Relamination in Aortic Dissection Repair) Is Associated With Good Anatomical Results on the Distal Thoracoabdominal Aorta at 2 Years

PURPOSE

The aim of this comparative study was to evaluate the increased aortic diameter of the distal aorta after implementing the STABILISE technique in complicated type B aortic dissection (AD).

DESIGN

This is a comparative monocentric retrospective study.

MATERIALS AND METHODS

All patients who underwent an STABILISE procedure for complicated AD between 2018 and 2020 were included and compared with a historic cohort treated with thoracic endovascular aortic repair (TEVAR) alone. Aortic diameters were measured at 6 different levels on the thoracic and abdominal aorta. The primary end point was an increased aortic diameter at 1 and 2 years. The exclusion criterion was the absence of a computed tomography (CT) scan at 1 or 2 years.

RESULTS

A total of 55 patients were included: 24 in the TEVAR group and 31 in the STABILISE group. At the level of the stent graft, there was a decrease in aortic diameters in both groups without significant differences. At the level of the distal aorta, there was an increase in aortic diameters in both groups without significant differences. There were significantly more patients in the TEVAR group with an unfavorable increase in aortic diameter >5 mm of the distal aorta at 2 years than in the STABILISE group: 8 (33%) vs 1 (3%) (p=0.01). For chronic ADs, a significantly greater increase in aortic diameters of the distal aorta was observed in the STABILISE group.

CONCLUSIONS

The STABILISE technique is technically feasible and potentially leads to decreased longer re-intervention rates; indeed, more patients had an unfavorable increase in aortic diameter in the TEVAR group than in the STABILISE group at 2 years. The high rate of long-term distal aortic aneurysm progression and reintervention after TEVAR alone suggests that this option is not sufficient to definitively treat these complex patients.

CLINICAL IMPACT

This article reported the results of stent assisted balloon induced intimal disruption and relamination (STABILISE) with a follow-up at 2 years. This is the first comparative study between STABILISE, which has emerged as a new technique inducing aortic remodeling and therefore better long-term outcome, and the standard technique TEVAR alone. STABILISE technique is associated with good results on the distal aorta at 2 years with a rate of patient with unfavorable aortic diameter evolution greater in TEVAR group compared to STABILISE group and could improve the long-term results on the distal aorta by inducing extensive aortic remodeling.

Aortic remodeling following hybrid arch repair with zone 0 to 5 thoracic endovascular aortic repairs for complex arch and descending thoracic aortic pathologies

Objective

For high-risk patients with aortic arch pathology, hybrid aortic arch repair with simultaneous or staged thoracic endovascular repair of the descending aorta may be a viable alternative to open repair. However, data on postintervention aortic remodeling remain limited. We report the short-term outcomes of remodeling of the thoracoabdominal aorta after hybrid arch repair + thoracic endovascular repair.

Methods

All patients undergoing hybrid arch repair with planned zones 0 to 5 thoracic endovascular repair from January 2020 to March 2022 were retrospectively reviewed. Computed tomography angiography scans preoperatively, after hybrid aortic arch repair, and on long-term follow-up were analyzed for thoracoabdominal aorta remodeling. Mean change in aortic true luminal diameter and full luminal diameter was calculated at every level, and paired-samples t test was used to compare means.

Results

Of 39 patients, 38 had follow-up data at a mean duration of 14.9 months. There were a total of 3 (7.7%) deaths, 0 (0.0%) strokes, and 0 (0.0%) paralysis. For the 35 patients undergoing thoracic endovascular repair for aortic dissection, at follow-up, there was a significant increase in the mean true luminal diameter at each level (P < .05), except at the aortic bifurcation and common iliac arteries. The largest increase in mean true luminal diameter (P < .01) was observed at the level of the left inferior pulmonary vein (mean difference +13.22 mm, 95% CI, 10.38-16.07), tracheal carina (mean difference +13.06 mm, 95% CI, 10.05-16.07), and inferior left atrium (mean difference +11.19 mm, 95% CI, 7.84-14.53).

Conclusions

Hybrid arch repair with zones 0 to 5 leads to improved true lumen augmentation in zones 0 to 8 with complete false lumen thrombosis down to zone 5 at short-term follow-up. Zones 9 to 11, if involved, may require adjunctive treatment strategies for total aortic remodeling and complete false lumen obliteration.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

The Caged Knickerbocker: A Novel Modification to Targeted False Lumen Management in Complex Aortic Dissection

INTRODUCTION

Targeted false lumen management has been described for complex presentations of aortic dissection. The "Knickerbocker" technique is often referenced and includes dilating a focal portion of an oversized endograft in the true lumen to purposefully rupture the false lumen septum, but at the expense of increased risk for visceral propagation and malperfusion. This case series describes a novel modification of the Knickerbocker technique by caging the distal end of the endograft prior to focal dilation.

METHODS

A retrospective chart review was conducted at a tertiary academic center from 2018-2020. Patients were included if they had a history or current presentation of aortic dissection and underwent a Caged Knickerbocker (CKB) repair. Data were collected to include demographics, indications for repair, technical success, perioperative outcomes, hospital course, mortality, and further aortic interventions.

RESULTS

Five patients were included in our evaluation. Four patients (80%) presented with chronic Type B aortic dissection (cTBAD) and concomitant aneurysmal degeneration of the thoracic aorta; 1 patient (20%) presented with an acute rupture secondary to cTBAD. Three patients (60%) had previous aortic repairs, 2 of which were for Type A Aortic Dissection that additionally required redo sternotomy and total arch replacement prior to CKB. CKB was technically successful in all cases with no peri-operative complications. Two (40%) patients required further aortic intervention due to aneurysmal degeneration.

CONCLUSION

Achieving complete false lumen thrombosis is a considerable challenge when managing complex aortic dissections. Our data demonstrate the technical feasibly and early successful outcomes with the CKB approach. Importantly, CKB facilitates future distal extension into the para-visceral aorta in cases of complex thoracoabdominal aortic aneurysms. Further research should focus on discerning individual patients who will benefit from targeted false lumen management and compare outcomes between different approaches.

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.

Early aortic growth in acute descending aortic dissection

OBJECTIVES

Acute aortic dissection leads to the destabilization of the aortic wall, followed by an immediate increase in aortic diameter. It remains unclear how the aortic diameter changes during the dissection's acute and subacute phases. The aim of this study was to evaluate the change in aortic geometry within 30 days after the onset of a descending aortic dissection.

METHODS

Patients with acute type B and non-A non-B dissection who had at least 2 computed tomography angiography scans obtained within 30 days after the onset of dissection were evaluated. Exclusion criteria were a thrombosed false lumen, connective tissue disorders and endovascular or open aortic repair performed prior to the second computed tomography angiography.

RESULTS

Among 190 patients with acute aortic dissection, 42 patients met our inclusion criteria. Their aortic geometry was analysed according to the computed tomography angiography scans obtained between 0-3 (N = 35), 4-7 (N = 9) and 8-30 (N = 12) days after the dissection onset. The highest aortic diameter growth rate was observed in the first quartile of the thoracic aorta and measured 0.66 (0.06; 1.03), 0.29 (-0.01; 0.41) and 0.06 (-0.13; 0.26) mm/day at 0-3, 4-7 and 8-30 days after the dissection, respectively. Proximal entry location (P = 0.037) and entry located at the arch concavity (P = 0.008) were associated with a higher aortic diameter increase.

CONCLUSIONS

Early rapid growth occurs during the first week after the descending aortic dissection-most intensely over the first 3 days, and this is associated with the location of the dissection's entry.

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.

Remodeling of Aortic Configuration and Abdominal Aortic Branch Perfusion After Endovascular Repair of Acute Type B Aortic Dissection: A Computed Tomographic Angiography Follow-Up

Background: Thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) induces false lumen (FL) thrombosis, promotes favorable aortic remodeling, and makes an impact on abdominal aortic branch perfusion patterns. However, little is known about the long-term fate of aortic remodeling and abdominal aortic branch perfusion after TEVAR for TBAD and the effect of FL thrombosis status on these changes.

Materials and methods: Between January 2014 and May 2021, 59 enrolled patients with acute TBAD were treated with TEVAR and had post-operative or follow-up images. Pre-operative, post-operative, and latest follow-up CT angiography (CTA) data were analyzed for the largest diameter of true lumen (TL), FL, and transaorta and for the FL thrombosis status on the stented thoracic aorta, unstented thoracic aorta, and abdominal aorta. Abdominal aorta perfusion patterns were characterized.

Results: The mean follow-up period was 17.1 months. In the stented thoracic aorta, average TL diameters increased, average FL diameters decreased, and average transaortic diameters did not change; 82.6% of the patients had either a stable or shrinking transaortic size and 87% of the patients achieved total FL thrombosis. In the unstented thoracic aorta, average TL diameters increased, transaortic growth and no changes occurred in 39.1 and 45.7% of the patients, respectively, and complete FL thrombosis was present in 50% of the patients. In the abdominal aorta, average FL and transaortic diameters increased, aorta was expanded in 52.2% of the patients, and FL remained patent in 65.2% of the patients. Of the 354 branches, 37 branches (10.5%) exhibited changes in perfusion patterns, 22 branches (6.2%) demonstrated an increased TL perfusion, and 15 branches (4.2%) had an increased FL contribution. Compared with patent or partially thrombosed FL, complete FL thrombosis was accompanied by a bigger decrease in FL diameters, a larger increase in TL diameters, and a higher percentage of abdominal branch TL perfusion.

Conclusions: In majority of the patients, TEVAR stabilized the size of the stented thoracic aorta, namely TL expansion and FL obliteration. However, abdominal aortic FL remained patent FL, and it was expanded with the resultant transaortic growth over a long follow-up period. Abdominal aortic branch perfusion patterns remained largely stable after TEVAR. The failure to achieve FL thrombosis negatively affects the remodeling of a contagious abdominal aortic dissection.

Therapeutic window for obtaining favorable remodeling after thoracic endovascular aortic repair of type B aortic dissection

OBJECTIVE

The purpose of the present study was to determine the most appropriate timing for thoracic endovascular aortic repair (TEVAR) of type B aortic dissection (TBAD) in terms of remodeling of the aorta.

METHODS

A total of 41 patients who had undergone TEVAR for the treatment of aortic dissection were included in the present study. The patients were divided into two groups: those who had undergone TEVAR in the acute or subacute phase (group A) and those who had undergone TEVAR in the chronic phase (group B). The indications for TEVAR as the treatment of TBAD were the presence of aortic rupture or malperfusion of the aortic branches, a maximum aortic diameter of ≥40 mm on the initial diagnostic computed tomography scan, and/or expansion of the aorta of ≥5 mm within 3 months for acute and subacute TBAD. The indication was a maximum aortic diameter of ≥50 mm or expansion of the aorta of ≥5 mm within 1 year for chronic TBAD. The diameters of the aorta, true lumen, and false lumen were measured at the level of the most dilated part of the descending aorta (level M) and at the diaphragm (level D) on the computed tomography scan obtained before TEVAR and at the 2-year follow-up examination.

RESULTS

The median interval between TEVAR and the onset of TBAD was 0.2 month (interquartile range, 0.03-0.7 month) in group A (n = 21) and 32 months (interquartile range, 4.7-35.2 months) in group B (n = 20). Except for the aortic diameter at level D in group B, favorable remodeling was obtained at both levels in both groups. The diameter change ratio of the aorta at level D was significantly greater in group A than in group B (P = .02). Receiver operating characteristic curve analysis of the interval for a significant decrease in the aortic diameter at level D yielded 4.2 months as the optimal threshold for performing TEVAR (area under the curve, 0.859; 95% confidence interval, 0.7-1.0).

CONCLUSIONS

TEVAR for TBAD will result in favorable outcomes, irrespective of the timing of the procedure. However, it might be more effective to perform TEVAR within 4.2 months of the onset of TBAD, provided that the TEVAR procedure can be performed safely.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Retrospective analysis of factors associated with aortic remodeling in patients with Stanford type B aortic dissection after thoracic endovascular aortic repair

Objective

Acute aortic dissection is a life-threatening condition. Thoracic endovascular aortic repair (TEVAR), together with optimized medical treatment, is currently the first line treatment for acute Stanford type B aortic dissection. TEVAR can close the entry tear and reduce mortality. Aortic remodeling after TEVAR can directly affect the patient’s long-term prognosis. The factors that influence aortic remodeling have, however, received insufficient clinical attention and remain unclear. It is very important to identify these factors.

Methods

A total of 100 patients were continuously enrolled from 2011 to 2018 in 2 centers. Relevant data, including time from hospital admission to surgery, medicine use and aortic computed tomography angiography images obtained before and 6 months after surgery were collected. Patients were divided into favorable and adverse aortic remodeling groups, according to the degree of aortic remodeling. Analysis of variance and the chi-square test were performed using SPSS software to compare differences between groups and to determine the factors that influence postoperative aortic remodeling.

Results

The proportion of single-stent implantations was higher in the favorable remodeling group than in the adverse remodeling group (79.5% vs. 53.8% in distal end of stent-graft level and 81.3% vs. 56.4% in diaphragm level, respectively, p < 0.05). The earlier the TEVAR procedure was performed, the better the aortic remodeling (3.4 days vs. 4.8 days in distal stent graft levels, and 3.6 days vs. 4.9 days in diaphragm level, respectively, p < 0.05), the presence of residual distal entry tears in the abdominal aorta also improved aortic remodeling after TEVAR (85.7% vs. 55.1% in the celiac trunk level, and 92.0% vs. 48.9% in the right renal artery level, respectively, p < 0.05).

Conclusion

Single stent-graft implantation and early surgery were associated with favorable aortic remodeling. Distal entry tears were also conducive to aortic remodeling after surgery for aortic dissection.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-021-01571-2.

Laser-assisted "Scissor" Technique to Facilitate Thoracic Endovascular Aortic Repair for Chronic Type B Aortic Dissection

INTRODUCTION

There has been an increase in utilization of thoracic endovascular aortic repair (TEVAR) to treat aneurysms with chronic dissection. Despite significant progress, TEVAR is hindered by persistent perfusion of the false lumen and aneurysm growth. Various techniques to address false lumen perfusion exist. We preset our experience of laser fenestration with disruption of the dissection flap to facilitate TEVAR and avoid persistent retrograde false lumen perfusion.

METHODS

Review a technique to treat patients with thoracic aortic aneurysm complicated by chronic dissection. This is an adjunct to a TEVAR procedure with final goal to treat the aneurysm and avoid retrograde false lumen perfusion. Under IVUS guidance, we performed a Phillips/Spectranetics laser fenestration of the intimal flap followed by a scissoring technique to obliterate the dissection flap and create a distal seal zone. Stent-grafts placed following flap obliteration allow graft expansion and apposition to the entire outer aortic and avoid retrograde perfusion of the false lumen.

RESULTS

Two patients underwent TEVAR in conjunction with laser obliteration of the dissection flap, including one undergoing primary repair of a chronic Type B dissection with aneurysm, and one as a completion second stage elephant trunk procedure. Technical success was achieved in both cases, with successful implantation of the endograft, and freedom from type I and III endoleaks. Absence of false lumen flow, and patency of the visceral vessels was confirmed on completion angiography. True lumen patency and obliteration of the intimal flap were confirmed by IVUS. Early follow up confirms exclusion of the aneurysm, with no evidence of retrograde perfusion of the false lumen.

CONCLUSIONS

Thoracic aortic aneurysms in the context of chronic dissections can be successfully treated with TEVAR and laser obliteration of the chronic dissection flap to fully exclude the aneurysm and avoid retrograde false lumen perfusion.

Aortic remodeling and competitive flow after surgical treatment of aortic dissection

Aortic remodeling after dissection is poorly understood and remains a focus of current research. In the present report, we have described the cases of two patients with acute lower extremity ischemia related to malperfusion from aortic dissection treated with extra-anatomic axillobifemoral bypass. During long-term follow-up, aortic remodeling led to reinstitution of flow through the native aorta. This resulted in competitive flow, leading to complete thrombosis of the extra-anatomic conduits. These cases highlight the occurrence of spontaneous aortic recanalization and subsequent competitive flow, two vascular phenomena that are not well understood but can significantly affect patient outcomes.

Epidemiology of aortic dissection

Aortic dissection remains a highly morbid diagnosis. The treatment of aortic dissection has undergone several paradigm shifts since it was first understood. However, despite the robust research in treatment, the epidemiology of aortic dissection is limited. In this review, we discuss the historical perspectives of aortic dissection with a review of risk factors and presentation. We review the trends in incidence during the past 40 years, with consideration for sex, race, and ethnicity in admission. We further focus our discussion of the classically described Type B aortic dissection treatment. Lastly, we review the impact of long-term events, readmissions, cost assessments, and quality of life studies of patients with aortic dissection. Care for those with aortic dissection remains a long-term challenge for providers and a multispecialty approach is needed for complete patient management.

Clinical Outcomes of Distal Tapered Restrictive Covered Stent Applied in Endovascular Treatment of Aortic Dissection Involving Zone 0

OBJECTIVE

The safety and efficacy of a distal tapered restrictive covered stent (RCS) applied in the endovascular treatment of aortic dissection involving Zone 0 was evaluated.

METHODS

This study retrospectively analysed 43 patients with acute aortic dissection involving Zone 0 who received in situ laser fenestrated thoracic endovascular aortic repair with distal tapered RCS from January 2015 to February 2019. The indication for the distal tapered RCS procedure was an inappropriate distal size of the main stent graft. Technical success, aortic remodelling, and clinical outcomes were evaluated.

RESULTS

Technical success was achieved in all patients. The 30 day post-operative mortality rate was 0%. All patients had complete false lumen thrombosis in the stent coverage segment. True lumen volume increased significantly (p < .001) with an average change of 87.0% ± 34.3%, while false lumen volume decreased significantly (p < .001) with an average change of -71.0% ± 13.5% between baseline and 12 months. During the follow up period (mean 28.7 months, range 12-63 months), no distal stent graft induced new entry (SINE) was observed. The average distance between the distal end of the RCS and the coeliac trunk was 57.5 mm. Two (4.7%) patients had spinal cord ischaemia (SCI) and recovered without permanent paraplegia after undergoing conservative treatment.

CONCLUSION

The distal tapered RCS applied in the endovascular treatment of aortic dissection involving Zone 0 is considered to be a feasible and effective approach along with satisfactory aortic remodelling, a low risk of SINE, and SCI. The favourable results are partly explained by selection. No patients had an entry tear near the coronary artery, nor were the coronary arteries, pericardium, or aortic valve involved at the time of repair.

Technique-Based Evaluation of Clinical Outcomes and Aortic Remodelling Following TEVAR in Acute and Subacute Type B Aortic Dissection

INTRODUCTION

To evaluate the clinical outcomes and aortic remodelling rates following thoracic endovascular aortic repair (TEVAR) for acute or subacute type B aortic dissection (TBAD) based on technique.

MATERIAL AND METHODS

All TEVARs for acute/subacute TBAD between 01/01/2008 and 01/06/2020 were included. TEVARS were grouped by technique (TEVAR only, PETTICOAT and STABILISE). Aortic remodelling was assessed at three aortic levels on follow-up CT. Thirty-day technical/clinical success rates, re-intervention rates and complications were recorded.

RESULTS

A total of 29 patients were included. The median age was 55 years (31-82). The median duration from initial presentation to TEVAR was 7 days (0-84). Intra-procedural complications included one aortic rupture from balloon moulding in a STABILISE case. Thirty-day mortality, stroke, spinal cord ischaemia and visceral ischaemia were 3% (n = 1), 3% (n = 1), 3% (n = 1) and 3% (n = 1), respectively. (All occurred in acute TBAD.) Overall survival was 50.5 months (18-115). Median follow-up was 31 months (1-115). Six patients (21%) required re-intervention, with a median time of 5 months (5-46) from first TEVAR. Overall complete aortic remodelling rates were: 89% at the proximal descending thoracic aorta, 78% at the distal thoracic aorta and 50% at the infra-renal abdominal aorta. At the infra-renal aorta, the STABILISE group (n = 11) had a higher complete aortic remodelling rate (82%) compared to TEVAR alone (n = 12) (20%).

CONCLUSION

Endovascular intervention for acute and subacute TBAD is safe with a high rate of technical success. STABILISE results in higher aortic remodelling at the infra-renal aorta (82%) compared to TEVAR alone (20%) but risks aortic rupture from balloon moulding.

Modified selective aortic root reconstruction with valve repair for treatment of Stanford A aortic dissection

Background

Acute aortic dissection is a serious emergency with a significant impact on mortality and morbidity. Many patients present with hemodynamic instability that may prevent them from being transported to more experienced centers. We aim to present our experience with a modified limited root approach in terms of the operative details and early results.

Results

This retrospective study included 27 patients who presented with Stanford A aortic dissection and underwent modified selective root replacement. All patients were followed up using transthoracic echocardiography at 6 months postoperatively and at yearly intervals thereafter. Computed tomography (CT) angiography was performed 12 months after the initial surgery.

A total of 92.6% of patients required concomitant aortic valve repair. There was no operative mortality related to the operation itself; however, four patients died during the follow-up period. One patient developed new severe aortic regurgitation in the 6th month of follow-up. One patient developed a pseudoaneurysm related to the suture line that was diagnosed by CT angiography in the 16th month of follow-up.

Conclusions

The early results of modified selective root reconstruction with aortic valve repair are promising. This procedure is a quick, reliable, easily reproducible, and technically undemanding valve-sparing treatment for acute aortic root dissection.

Aortic remodelling after thoracic endovascular aortic repair in acute and chronic type B aortic dissections

OBJECTIVES

Type B aortic dissections are routinely treated with thoracic endovascular aortic repair (TEVAR). The timing for TEVAR remains controversial and might have an impact on the remodelling capacity of the aorta. This study analyses and compares aortic remodelling in acute (ABD) and chronic (CBD) type B aortic dissections after TEVAR.

METHODS

This retrospective study analysed the preoperative, postoperative and at least 1-year follow-up computed tomography of 53 TEVAR patients (36 ABD, 17 CBD) at a single institution between May 2005 and May 2016. The volumes of aortic lumen (AL), true lumen, false lumen (FL) and perfused FL were measured at the stent graft level (A), from the stent graft to the coeliac trunk (B) and from the coeliac trunk to the bifurcation (C). The absolute volumes, normalized volume changes and FL thrombosis rate of ABD and CBD patients were compared.

RESULTS

Absolute AL and FL of segment A were significantly larger in CBD patients compared to ABD patients preoperatively (AL: 354 ± 68 vs 255 ± 51 ml, P = 0.023, FL: 253 ± 56 vs 183 ± 35 ml, P = 0.028) until last follow-up (AL: 462 ± 52 vs 246 ± 52 ml, P = 0.003, FL: 268 ± 202 vs 91 ± 31 ml, P = 0.004). The true lumen in segment A increased more in ABD than in CBD patients preoperatively to postoperatively (112% vs 36% P < 0.001) and within the first year postoperatively (171% vs 80% P < 0.001). FL in segment A decreased more in ABD compared to CBD patients within the first year (-42% vs -13% P < 0.001) and thereafter (-50% vs +6% P = 0.002). In segments B and C, the FL thrombosis rate was higher in ABD than in CBD patients at all time points and significantly higher in segment A after the first year (91% vs 98% P = 0.035).

CONCLUSIONS

Aortic remodelling after TEVAR is significantly different in acute and chronic dissection patients. TEVAR promotes aortic remodelling in both acute and chronic dissections in terms of true lumen increase at stent graft level. Nevertheless, significant AL reduction by FL shrinkage is primarily found in ABD.

Hybrid two-stage repair of Stanford A dissection with visceral or peripheral malperfusion

Background

The present study aimed to evaluate the effect of two-stage hybrid aortic repair at the distal aorta of Stanford A dissection with malperfusion.

Methods

This retrospective case series included 20 patients with Stanford A dissection administered two-stage thoracic endovascular aortic repair (TEVAR) about 1 month after central repair because of visceral or limb malperfusion. The patients were examined by computed tomography (CT) angiography at 3, 6, 12 and 24 months after operation. Recovery of malperfusion and true lumen index were evaluated during follow-up.

Results

Twenty patients underwent two-stage hybrid aortic repair, including 11 males and 9 females. The follow-up time was 24 ± 7 months. No intervention-related complications were observed, including stent graft-induced new re-entry tears, death, stroke and spinal cord injury. Malperfusion in all cases was corrected. The true lumen was not enlarged enough 1 month after the first surgery. Thrombosis of the false lumen was observed around the elephant trunk at the carina level and the celiac artery. Three months after second stage TEVAR, the false lumen thrombosis was resorbed; in addition, the trunk was fully expanded at the carina level, and the true lumen was enlarged at the celiac artery.

Conclusions

Two-stage hybrid aortic repair for residual true lumen in the distal aorta 1 month after initial surgery is helpful for descending aorta remodeling and effective in treating malperfusion. This procedure may be a good option for patients suffering from Stanford A dissection with small true lumen in the distal aorta and malperfusion.

Twelve-Month Computed Tomography Follow-Up after Thoracic Endovascular Repair for Acute Complicated Aortic Dissection

BACKGROUND

To explore the impact of thoracic endovascular aortic repair (TEVAR) on aortic remodeling (AR) and the relationship between AR and complications after TEVAR.

METHODS

A total of 56 patients (2 type IIIA aortic dissection [AD] and 54 type IIIB AD) with complicated acute type B aortic dissection suitable for TEVAR were prospectively enrolled. There were 44 men (78%) and 12 women (22%) with an average age of 54 ± 13.8 years. Aortic enhanced computed tomography (CT) was performed pre-TEVAR and 3, 6, and 12 months postoperatively. The morphological changes in AR, namely aortic volume and false lumen thrombosis, were obtained by analyzing the CT data. The effect of TEVAR on AR was determined by the morphological changes in the aorta. The relationship between AR index, false lumen thrombosis, and complications was analyzed.

RESULTS

The volume of the thoracic aortic true lumen gradually increased post-TEVAR, whereas the volume of the thoracic aortic false lumen gradually decreased. The volume of abdominal aortic total lumen and false lumen increased 6 months postoperatively. The AR index increased significantly 3 months postoperatively, which was negatively correlated with complications and mortality. The thoracic and abdominal aortic false lumen thrombosis developed gradually after TEVAR, and the degree of thoracic aortic false lumen thrombosis was negatively correlated with complications and mortality.

CONCLUSIONS

TEVAR promotes AR. AR index and the degree of thoracic aortic false lumen thrombosis can serve as predictors of complications and mortality.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Management of the Left Subclavian Artery in TEVAR for Chronic Type B Aortic Dissection

Objectives:

Left subclavian artery (LSA) revascularization in thoracic endovascular aortic repair (TEVAR) remains controversial. Left subclavian artery coverage without revascularization can cause stroke and death. TEVAR has gained popularity for the treatment of chronic type B aortic dissection (cTBD). Using the Vascular Quality Initiative (VQI) database, we reviewed outcomes of LSA revascularization in TEVAR for cTBD.

Methods:

The VQI registry identified 5683 patients treated with TEVAR from July 2010 to July 2016, including 208 repairs for cTBD. We analyzed outcomes per the Society for Vascular Surgery reporting standards.

Results:

Of the 208 patients, 150 (72.1%) were male with a median age of 65.0 years (interquartile range [IQR], 55.0-72.0). Median aneurysm diameter was 5.7 cm (IQR, 5.0-6.5 cm). Data on the patency of the LSA was available in 131 (63.0%) patients. Twenty-five (19.1%) had occlusion of the LSA without revascularization, while 106 (80.9%) maintained patency or had revascularization. Successful device delivery occurred in all 131 (100%) patients. Maintaining LSA patency did not affect the rate of cerebrovascular accident ( P = .16), spinal cord ischemia ( P = 1.00), or death ( P = 1.00). This was also nonsignificant when analyzing the subgroup of 98 elective cases. There was no difference in the rates of endoleak. Any intervention for the LSA (revascularization or occlusion) led to a longer procedure time (203.6 minutes vs 163.7 minutes, P = .04).

Conclusions:

Maintaining LSA patency during TEVAR for cTBD offers no advantage in perioperative morbidity or endoleak. Occlusion of LSA may be performed safely in this cohort and revascularization reserved for those who have anatomy that compromises perfusion to critical organs.

CT-based True- and False-Lumen Segmentation in Type B Aortic Dissection Using Machine Learning

Purpose

To develop a segmentation pipeline for segmentation of aortic dissection CT angiograms into true and false lumina on multiplanar reformations (MPRs) perpendicular to the aortic centerline and derive quantitative morphologic features, specifically aortic diameter and true- or false-lumen cross-sectional area.

Materials and Methods

An automated segmentation pipeline including two convolutional neural network (CNN) segmentation algorithms was developed. The algorithm derives the aortic centerline, generates MPRs orthogonal to the centerline, and segments the true and false lumina. A total of 153 CT angiograms obtained from 45 retrospectively identified patients (mean age, 50 years; range, 22-79 years) were used to train (n = 103), validate (n = 22), and test (n = 28) the CNN pipeline. Accuracy was evaluated by using the Dice similarity coefficient (DSC). Segmentations were then used to derive the maximal diameter of test-set patients and cross-sectional area profiles of the true and false lumina.

Results

The segmentation pipeline yielded a mean DSC of 0.873 ± 0.056 for the true lumina and 0.894 ± 0.040 for the false lumina of test-set cases. Automated maximal diameter measurements correlated well with manual measurements (R ² = 0.95). Profiles of cross-sectional diameter, true-lumen area, and false-lumen area over several follow-up examinations were derived.

Conclusion

A segmentation pipeline was used to accurately identify true and false lumina on CT angiograms of aortic dissection. These segmentations can be used to obtain diameter and other morphologic parameters for surveillance and risk stratification.Supplemental material is available for this article.© RSNA, 2020.

Techniques and outcomes of total aortic arch repair with frozen elephant trunk for DeBakey I dissections

Total aortic arch replacement (TAR) with frozen elephant trunk (FET) technique (FET) has been increasingly used to treat a variety of aortic pathologies over the past two decades. Because FET can effectively treat the diseased arch and cover the proximal entry tear in the distal arch, it is a valuable option in the treatment of DeBakey I aortic dissections. This report focuses on the techniques and outcomes of TAR with FET for acute/chronic aortic dissection. A review of pooled literature including 27 observational studies showed in-hospital mortality, permanent stroke, and spinal cord injury rates of 8.4%, 5.9% and 2.6% for acute aortic dissections, and 7.5%, 4.0% and 4.6% for chronic aortic dissections, respectively. In most of the studies, complete false lumen thrombosis rate was achieved in 80% of patients at the level of FET for acute and chronic aortic dissections. Mid-term outcomes are equally promising. For chronic aortic dissections, positive remodeling of the non-stented distal aortic segments is less frequent leading to secondary reinterventions within 3 to 5 years. However, most studies have not applied distal abdominal extensions of the repair using fenestrated and branched endografts. In the current endovascular era, TAR + FET should be considered as an alternative to conventional open surgical repair in centers of excellence.

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Dynamic Indicators That Impact the Outcomes of Thoracic Endovascular Aortic Repair in Complicated Type B Aortic Dissection

PURPOSE

To investigate dynamic variables obtained from retrospective computed tomography angiography for ability to predict thoracic endovascular aortic repair (TEVAR) outcomes in patients with complicated type B aortic dissection (cTBAD).

MATERIALS AND METHODS

Seventy-nine patients with cTBAD who received TEVAR from March 2009 to June 2018 were retrospectively enrolled. Relative true lumen area (r-TLA) was computed at the level of tracheal bifurcation every 5% of all R-R intervals. Parameters that reflect the state of intimal motion were evaluated, including difference between maximum and minimum r-TLA (D-TLA) and true lumen collapse. The endpoints comprised early (≤ 30 days) and late (> 30 days) outcomes after intervention.

RESULTS

Overall early mortality rate was 13.9% (11/79), and early adverse events rate was 24.1% (19/79). Patients who received TEVAR within 2 days of symptom onset demonstrated the worst outcomes. A longer time of r-TLA < 25% in 1 cardiac cycle (P = .049) and larger D-TLA (P < .001) were correlated to an increased early death. In addition, D-TLA was an independent predictor of early mortality. Area under the curve of D-TLA was 0.849 (95% confidence interval 0.730-0.967) for predicting early mortality and 0.742 (95% CI 0.611-0.873) for predicting early adverse events. Survival and event-free survival rates during follow-up were decreased in the D-TLA > 21.5% group compared with the D-TLA ≤ 21.5% group (all P < .001).

CONCLUSIONS

Larger D-TLA is correlated with worse postoperative outcomes and might be a crucial parameter for future risk stratification in patients with cTBAD.

Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) Reporting Standards for Type B Aortic Dissections

This Society for Vascular Surgery/Society of Thoracic Surgeons (SVS/STS) document illustrates and defines the overall nomenclature associated with type B aortic dissection. The contents describe a new classification system for practical use and reporting that includes the aortic arch. Chronicity of aortic dissection is also defined along with nomenclature in patients with prior aortic repair and other aortic pathologic processes, such as intramural hematoma and penetrating atherosclerotic ulcer. Complicated vs uncomplicated dissections are clearly defined with a new high-risk grouping that will undoubtedly grow in reporting and controversy. Follow-up criteria are also discussed with nomenclature for false lumen status in addition to measurement criteria and definitions of aortic remodeling. Overall, the document provides a facile framework of language that will allow more granular discussions and reporting of aortic dissection in the future.

Instabilities in Aortic Length After TEVAR and Reoperation: 12 Years of Follow-Up Imaging

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) remains an important minimally invasive tool for the treatment of descending thoracic aneurysm. The long-term effects of these repairs in reduction of the aneurysmal sac size as well as stability of the stented portion require study. We report the results of 12 years of radiographic follow-up.

METHODS

All patients who underwent TEVAR for descending thoracic aneurysms from January 2005 to December 2017(n = 371) were evaluated for immediate postoperative and follow-up computed tomographic scans suitable for 3-dimensional reconstruction of the aorta (excluding those with an interim reoperation). We found 62 patients who met these criteria (median duration of radiographic follow-up, 1.8 years). Measurements were taken of centerline, greater and lesser curvatures from the most distal patent brachiocephalic vessel to the first uncovered mesenteric vessel, and between proximal and distal edges of the stented portion of the aorta.

RESULTS

All measured segments, except covered length, were significantly increasing in length for centerline, greater and lesser curvatures, with a median increase of 7.6 mm (interquartile range, 1.7-16 mm). Cox regression for mortality and reoperation found no significant correlation between these changes and mortality and a significant correlation between stented segment greater curvature increase and reoperation (adjusted hazard ratio, 1.06; P < .05).

CONCLUSIONS

Increases in the centerline and greater curve length of the aorta were found to be occurring. This appears to be primarily driven by growth in the nonstented segments. However, changes in the outer curve length of the stented segment were associated with a greater risk of reoperation.

Surgical Outcomes And Postoperative Descending Aorta Morphologic Remodeling After Thoracic Endovascular Aortic Repair For Acute And Chronic Type B Aortic Dissection

Background

This study aims to investigate the descending aortic morphological alterations caused by pathological changes in acute and chronic Type B aortic dissection (TBAD) and morphological remodeling after thoracic endovascular aortic repair (TEVAR).

Patients and methods

From February 2012 to January 2016, 86 TBAD patients undergoing TEVAR were divided into an acute group (n=63) and a chronic group (n=23). The areas of the true, false and maximal lumen and descending aorta morphological parameters, including the taper ratio (TR), oversizing ratio (OR), mismatch ratio (MR), radius of curvature (RoC) and tortuosity index (TI), were evaluated. Follow-ups were performed postoperatively before discharge, at 1 and 6 months, and yearly thereafter.

Results

Before TEVAR, the TR (0.57 (0.49) vs 0.74 (0.60); P < 0.05), OR (2.75 ± 1.89 vs 3.96 ± 2.27; P < 0.05) and TI (1.22 (1.19) vs 1.41 ± 0.17; P < 0.05) were significantly higher in the chronic group than in the acute group. The TEVAR technical success rate was 100%. No differences were found in 30-day and >30-day mortality between the two groups. Pathology-specific devices, such as tapered stent grafts and distal bare stents, were used more frequently in the chronic group than in the acute group (47.8% vs 23.8%, P = 0.03; 43.5% vs 12.7%, P = 0.002, respectively). The OR and TI changes that occurred after TEVAR were significantly higher in the chronic group than in the acute group (1.80 ± 0.86 vs 2.98 ± 1.85, P = 0.028; 0.00 ± 0.09 vs 0.09 ± 0.10, P < 0.001, respectively).

Conclusion

TEVAR is a safe and effective therapy for acute and chronic TBAD. Compared to acute TBAD, chronic TBAD resulted in an adverse preoperative descending aorta morphology. Pathology-specific devices may be a feasible treatment option for endovascular repair of chronic TBAD. A larger series of cases with longer follow-up are needed to draw definitive conclusions.

Assessing Aortic Remodeling after Thoracic Endovascular Aortic Repair (TEVAR) in DeBakey IIIb Aortic Dissection: A Retrospective Study

PURPOSE

This study analyzed the different levels of aortic remodeling in patients with DeBakey IIIb aortic dissection (AD) after thoracic endovascular aortic repair (TEVAR) at a single center.

METHODS

In all, 66 patients with DeBakey IIIb AD who underwent TEVAR in the acute (Group A) or subacute phase (Group SA) from January 2012 to October 2016 were included in the study. The change in aortic lumen (A), true lumen (TL), false lumen (FL), and true lumen index (TLi) at different levels were analyzed.

RESULTS

There was no statistically significant difference in the clinical information and morphologic imaging findings in Groups A and SA. At proximal levels (levels A-C), there was no difference in aortic remodeling parameters, that is, increased TL, decreased FL, and increased TLi at levels B and C and stable A at levels A-C, in both groups. Moreover, the above parameters were illustrated using a box-and-whisker plot, which revealed the unstable acute phase by the larger distribution interval and the median and abnormal values of the right skew distribution in Group A.

CONCLUSION

Postoperative surveillance is important for patients of both acute and subacute AD.

Predictors of Failure of Medical Management in Uncomplicated Type B Aortic Dissection

BACKGROUND

Optimal medical therapy (OMT) for uncomplicated type B aortic dissection (uTBAD) provides excellent short-term outcomes but is associated with a high incidence of failure. This study identified predictors of aortic intervention and mortality in uTBAD patients undergoing OMT.

METHODS

A retrospective review of the Emory University School of Medicine aortic database identified 314 uTBAD patients undergoing OMT from 2000 to 2016. Two hundred sixty-three (84%) patients had imaging at presentation analyzed for maximum aortic diameters (ADs), false lumen (FL) status, and visceral vessel perfusion. Cox proportional hazards models were constructed to estimate hazards ratios (HRs) and identify predictors of OMT failure.

RESULTS

The mean age of patients was 58 ± 12 years, and 67% were men. FL status was patent in 59.4%, partially thrombosed in 39.8%, and completely thrombosed in 0.8% of patients. Over a median follow-up of 5.6 (interquartile range, 1.4 to 8.5) years, 44.9% of patients failed OMT and underwent intervention (n = 58 open, n = 83 endovascular). The estimated incidence of OMT failure was 46%. Multivariate analysis identified the presence of diabetes, renal failure, DeBakey 3B dissection, and a descending thoracic AD of 4.5 cm or greater (HR, 1.39; 95% confidence interval, 1.24 to 1.56; p < 0.001) to be independent predictors of failure of OMT. FL status or the distribution of visceral vessels arising from the FL did not predict OMT failure.

CONCLUSIONS

There is a significant incidence of OMT failure in uTBAD patients. A descending thoracic AD of 4.5 cm or greater at the time of diagnosis is an independent predictor of failure of OMT.

[Elimination of late endoleak after endovascular repair of a dissecting thoracoabdominal aortic aneurysm]

Described herein is a clinical case report regarding treatment of a 70-year-old male patient presenting with a late complication following endoprosthetic repair for a Stanford type B dissecting thoracic aortic aneurysm. The man was admitted to our hospital for persistent type IIb endoleak and an increased diameter of the aorta in its thoracic and thoracoabdominal portions. Two years previously, he had endured endoprosthetic repair of the thoracic aorta. The findings of computed tomography revealed negative dynamics manifesting as an increase in the diameter of the false channel of the arch and descending thoracic aorta with persistent type IIb endoleak. He was subjected to elimination of abdominal aortic dissection and type IIb endoleak with partial prosthetic repair of the descending thoracic portion of the aorta by means of prosthetic repair of the lower thoracic portion of the aorta between the stent graft and linear vascular Dacron prosthesis. The postoperative period was complicated by transient acute renal failure and paraparesis of the lower limbs. The patient was discharged on POD 14, with no endoleaks revealed on control computed tomography 3 months thereafter.

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.

Ectopic Expression of PCSK9 by Smooth Muscle Cells Contributes to Aortic Dissection

BACKGROUND

Acute aortic dissection (AAD) is a common disease among the elderly. Although several risk factors of AAD have been reported, the molecular mechanism underlying AAD development remains to be elucidated. Proprotein convertase subtilisin/kexin type 9 (PCSK9) increases low-density lipoprotein cholesterol levels in blood by preventing its clearance. Therefore, PCSK9 inhibition is a promising therapeutic approach to treat cardiovascular diseases (CVDs). The objective of this study was to elucidate the role of PCSK9 in the pathogenesis of AAD.

METHODS

We used fluorescence immunohistochemistry to assess PCSK9 expression in aortic tissues resected from 10 AAD patients and in the normal aorta from 5 autopsy samples as well as in spontaneously hyperlipidemic apolipoprotein E-deficient mice used as an experimental AD model.

RESULTS

We revealed a characteristic distribution pattern of PCSK9 in atherosclerotic plaques and the degenerated tunica media in AAD tissues, which was rarely observed in normal aortic tissues. Furthermore, PCSK9 was notably expressed around calcification areas formed by vascular smooth muscle cells, especially those of the synthetic phenotype. The results obtained in the animal model were consistent with PCSK9 expression in AAD tissues.

CONCLUSIONS

Our findings suggest that PCSK9 overexpression in the aorta may promote AAD. This study adds to the growing body of evidence supporting the use of PCSK9 inhibitors for the management of CVDs.

Comparison of thoracic endovascular aortic repair, open surgery and best medical treatment for type B aortic dissection: A meta-analysis

BACKGROUND

Treatments of type B aortic dissection (TBAD) include thoracic endovascular aortic repair (TEVAR), best medical treatment (BMT) and open surgery (OS). This meta-analysis was to compare these three strategies to evaluate which provides best outcomes.

METHODS

We searched clinical trials that compared treatment strategies for TBAD. The outcomes measures were 30-day/in-hospital mortality, long-term survival rate, paraplegia or paraparesis, renal failure, rupture, stroke, late re-intervention, late rupture and aneurismal dilatation/expansion.

RESULTS

Sixteen control trials covering 10,307 patients were evaluated. Meta-analysis showed that TEVAR provides preferable long-term survival rate (HR=0.71; 95% CI: 0.52-0.95), lower rate of late re-intervention (OR=0.33; 95% CI: 0.13-0.85), late rupture (OR=0.21; 95% CI: 0.10-0.43) and late aneurismal dilatation/expansion (OR=0.15; 95% CI: 0.04-0.63) compared with BMT. However, TEVAR seemed to be associated with higher stroke rate than BMT (OR=1.65; 95% CI: 1.21-2.23). 30-day/in-hospital mortality appeared to be lower in TEVAR (OR=0.49; 95% CI: 0.29-0.81) when compared with OS. In addition, OS induced higher 30-day/in-hospital mortality compared with BMT (OR=3.95, 95% CI: 1.56-10.02).

CONCLUSIONS

Our study shows that TEVAR may be favorable in long-term outcomes and effectively provide morphologic advantages compared to BMT. However, there is a need for prophylactic measures against stroke in TEVAR. OS seems to be inferior to TEVAR both in short-term and long-term outcomes. Further studies especially randomized clinical trials are needed to comprehensively compare the efficacy between TEVAR and BMT.

How should we manage type B aortic dissections?

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

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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