Should the distal tears of aortic dissection be treated? The risk of distal tears after proximal repair of aortic dissection

Frozen elephant use in type a dissection: fundamentals, innovations, and pitfalls

INTRODUCTION

Type A acute aortic dissection (TA-AAD) is a great challenge for aortic surgeons. The establishment of a standardized surgical approach, particularly the determination of whether and when to address the aortic arch and the distal aorta in the same operation as the proximal aorta, is still unclear.

AREAS COVERED

Frozen elephant trunk (FET) has emerged as a valuable treatment for TA-AAD over the last decade. Here, we discuss the fundamentals and pitfalls of frozen elephant trunk procedures and present the latest innovations.

EXPERT OPINION

FET has the potential to simplify arch reconstruction in patients with complex arch tears and rupture, optimize perfusion in the distal true lumen for those with a compressed true lumen and malperfusion, address distal reentry tears, and promote false lumen thrombosis and late aortic remodeling. Nevertheless, FET is still associated with non-negligible mortality and morbidity rates. Patient selection, surgical expertise, and postoperative care remain crucial determinants in ensuring successful outcomes. Recent innovations in FET surgery involve the development of techniques to minimize or avoid hypothermic circulatory arrest and new FET devices with different arch branch configurations aiming to facilitate subsequent aortic reinterventions. We believe that both these advancements have the potential to improve patient outcomes.

Volumetric analysis in primary and residual type B aortic dissection treated with stented-assisted balloon-induced intimal disruption and relamination technique can predict aortic reintervention

OBJECTIVE

The aim of this study was to investigate the mid-term results of stented-assisted balloon-induced intimal disruption and relamination (STABILISE) in patients with aortic dissection with the implementation of volumetric analysis.

METHODS

This was a single-center retrospective analysis of prospectively collected data. From May 2017 to September 2022, 42 patients underwent STABILISE for acute complicated or subacute high-risk aortic dissection. STABILISE was completed with distal extended endovascular aortic repair in 24 patients. A computed tomography scan was performed at baseline, before hospital discharge, and at 1, 3, and 5 years. Perfused total aortic, true lumen, and false lumen volumes were assessed for thoracic, visceral, and aorto-iliac segment. The ratio between false lumen and total volume was named perfusion dissection index (PDI). Complete remodeling was defined as PDI = 0, and positive remodeling as PDI ≤0.1.

RESULTS

Technical success was 97.6%. No 30-day deaths, spinal cord injuries, or retrograde dissections were observed. Mean follow-up was 44 ± 19.4 months. Thoracic diameter was lower at last available computed tomography scan (36.7 vs 33.0 mm; P = .01). Aortic growth >5 mm was observed in 9.5% of the patients. Thoracic and visceral aortic complete remodeling were 92.8% and 83.3%, respectively, with no difference between acute and subacute group. Distal extended endovascular aortic repair significantly increased complete remodeling in the aorto-iliac segment, compared with STABILISE alone (69.6% vs 21.4%; P < .001). Freedom from vascular reinterventions at 3 years was 83.1% (95% confidence interval, 71.5%-96.6%). Total PDI ≤0.1 at first postoperative control was a predictor of vascular reinterventions (P < .0001).

CONCLUSIONS

STABILISE is a safe and feasible technique associated with high mid-term rates of complete remodeling in the thoracic and visceral aorta. Volumetric analysis allows the quantification of aortic remodeling and represents a predictor of aortic reinterventions.

The Use of the Ascyrus Medical Dissection Stent in Acute Type A Aortic Dissection Repair Reduces Distal Anastomotic New Entry Tear

BACKGROUND

A distal anastomotic new entry tear (DANE) can occur at the time of surgical repair for acute type A aortic dissection (ATAAD). This study aimed to compare the occurrence of DANE following a standard hemiarch repair with that following a hemiarch repair with an uncovered arch dissection stent.

METHODS

All patients who received a hemiarch repair or a hemiarch repair with an Ascyrus Medical Dissection Stent (AMDS) for ATAAD from 2017 to 2021 were included. Baseline and intra- and postoperative characteristics were collected. All available pre- and postoperative computed tomographic scans were analysed. The primary outcome measures were the incidence of DANE, positive aortic remodelling, mortality, and aortic reintervention rates at last follow-up.

RESULTS

A total of 114 patients underwent repair of Debakey I ATAAD during the study period with either an isolated hemiarch (n = 77) or a hemiarch with AMDS (n = 37). There was no significant difference in mortality (P = 0.768) or other in-hospital adverse events. During the follow-up period, DANE occurred in 43.3% (n = 26) of the isolated hemiarch group and in 11.8% (n = 4) of the hemiarch with AMDS group (P = 0.002). The incidence of false lumen thrombosis and obliteration favoured the AMDS group in the aortic arch (P = 0.029), the proximal descending thoracic aorta (P = 0.031), and level of pulmonary artery bifurcation (P = 0.044).

CONCLUSIONS

The incidence of DANE is significantly reduced with the addition of an AMDS at the time of hemiarch repair for ATAAD repair. Further follow-up is necessary to identify late aortic complications that may have been prevented by reducing the incidence of postoperative DANE.

Case Report: The application of amplatzer vascular plug to repair aortic dissection intimal tears and false lumen

In recent years, significant advancements have been made in endovascular therapy for aortic dissection, resulting in the development of various treatment methods. Nevertheless, there is a contentious discussion regarding the suitability of different treatment methods for addressing the unique features of individual lesions. Specifically, the matter of whether the presence of small intimal tears or multiple distal tears requires extensive aortic coverage with graft stents, which may block the blood supply to important organs, intercostal arteries, or lumbar arteries, remains unresolved. Further research is necessary to determine the need for complex fenestrated or branched endovascular aortic repair (F/B-EVAR) in the management of chronic post-dissection aneurysms involving visceral arteries. Our report highlights the successful endovascular repair of three patients with aortic dissection, encompassing one Stanford A type and two Stanford B types. Utilizing the Amplatzer Vascular Plug (AVP) alone or in combination with the coil embolization technique, we achieved favorable clinical outcomes. This article aims to provide valuable insights and new perspectives on the tailored management of aortic dissection by conducting a comprehensive examination of the subtle differences in the treatment processes and techniques applied to these three patients.

Age-related difference in acute type B aortic dissection

OBJECTIVE

The objective is to compare the characteristics of clinical data, imaging data, and treatment methods of young and old patients with acute type B aortic dissection (ABAD).

METHODS

ABAD patients admitted to the Department of Vascular Surgery of the First Affiliated Hospital of Anhui Medical University from January 2012 to December 2018 were retrospectively reviewed. Patient demographics, such as gender, age, diabetes, hypertension, presenting symptoms, imaging characteristics, laboratory data on admission, hemodynamics on admission and in-hospital management, and mortality of different age groups were compared and analyzed. Categorical variables were compared using χ2 tests or Fisher's exact test. Continuous variables were compared using Student's t-test or Mann-Whitney U-test.

RESULTS

A total of 141 ABAD patients were included in this study. Old ABAD patients were more likely to have a prior history of hypertension (88.6% vs 70.4%, p = 0.037) and atherosclerosis (29.8% vs 7.4%, p = 0.016). In the young group, Marfan syndrome was significantly higher (14.8% vs 0.9%; p = 0.005). Compared with the old group, the number of distal tears in the young group was significantly higher (62.3% vs 39.5%, p = 0.027). The proportion of patients with malperfusion of lower limbs in the young group was significantly higher than that in the old group (22.2% vs 6.1%, p = 0.026). There was no significant difference in the treatment methods and in-hospital mortality between the two groups.

CONCLUSION

Compared with old ABAD patients, young ABAD patients had more distal tears and a higher proportion of lower limbs malperfusion.

Outcomes of abdominal false lumen embolization for chronic aortic dissection after prior proximal repair with stent-graft

BACKGROUND

Persistent false lumen (FL) perfusion with aneurysmal formation is common after thoracic endovascular aortic repair (TEVAR) for typical extended aortic dissection and is associated with poor outcomes. Endovascular FL embolization (FLE) has recently been tried for treatment of postdissection aortic aneurysm (PDAA). However, most reports address thoracic rather than abdominal FLE. In this study, we present the results of abdominal FLE in patients with residual patent abdominal FL following stent-graft repair for aortic dissection.

METHODS

Between 2015 and 2019, 24 patients (mean age: 56.7 ± 11.8 years, range: 40-84 years, 18 male) received endovascular abdominal FLE using vascular plugs, coils, or candy plugs as the main surgery (5 patients) or auxiliary procedure (19 patients) after earlier stent-graft repair for aortic dissection (Type A: 9, Type B: 15). The medical records were reviewed and aortic remodeling was examined comparing the preembolization computed tomography (CT) and the most recent CT before reintervention.

RESULTS

Technical success was achieved without any intraoperative complications, early morbidity, or mortality. Median follow-up was 34.4 months (range: 12-71). Regarding thoracic FL, 15 patients exhibited complete thrombosis before the procedure and did not change status thereafter except for 1 patient with distal stent-graft-induced new entry. In the other 9 patients, 6 exhibited increased thrombosis. With regard to the abdominal aorta, increased FL thrombosis only occurred in 8 patients with 3 (12.5%) achieving complete thrombosis. The maximal thoracic aortic diameter did not change (1.4 ± 5.6 mm) statistically, but the abdominal diameter increased significantly (4.3 ± 3.7 mm, p < 0.005).

CONCLUSION

From our results, abdominal FLE is a safe procedure. However, covering all the re-entry tears is complex and the possibility of complete FL thrombosis is low. The abdominal aortic diameter appears to become enlarged in these patients. Continuous follow-up is necessary after FLE.

Factors affecting distal false lumen enlargement after thoracic endovascular aortic repair for type B aortic dissection

Objective

To investigate the factors influencing distal false lumen enlargement after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection.

Materials and methods

Data were collected on patients with type B aortic dissection who underwent TEVAR from January 2008 to August 2022. Patients were divided into a distal aortic segmental enlargement (DSAE) group and a non-DSAE group based on whether the distal false lumen was dilated more than 5 mm on computed tomographic angiography (CTA) images. To analyze the independent influences on distal false lumen dilatation after TEVAR, the variables with a P value < 0.05 during univariate analysis were included in the binary logistic regression analysis model.

Results

A total of 335 patients were included in this study, with 85 in the DSAE group and 250 in the non-DSAE group. The mean age was 52.40 ± 11.34 years, 289 (86.27%) were male patients, and the median follow-up time was 6.41 (11.99-29.99) months. There were significant differences in Marfan syndrome, chronic obstructive pulmonary disease (COPD), and follow-up time between the two groups. In terms of morphology, there were statistically significant differences in the number of tears, the size of the primary tear, and the length of dissection between the two groups. Binary logistic regression analysis indicated that Marfan syndrome, COPD, and the primary tear size were associated with distal false lumen dilatation.

Conclusions

Marfan syndrome, COPD, and the primary tear size influence distal aortic segmental enlargement after TEVAR in type B aortic dissection patients.

Preoperative Predictors of Late Aortic Expansion in Acute Type B Aortic Dissection Treated with TEVAR

BACKGROUND

A patent false lumen (FL) in patients with thoracic endovascular aortic repair (TEVAR)-treated type B aortic dissection (TBAD) can cause a significant risk for late aortic expansion (LAE). We hypothesize that preoperative features can predict the occurrence of LAE.

METHODS

Sufficient preoperative and postoperative follow-up clinical and imaging feature data for patients treated with TEVAR in the First Affiliated Hospital of Nanjing Medical University from January 2018 to December 2020 were collected. A univariate analysis and multivariable logistic regression analysis were used to find potential risk factors of LAE.

RESULTS

Ninety-six patients were finally included in this study. The mean age was 54.5 ± 11.7 years and 85 (88.5%) were male. LAE occurred in 15 (15.6%) of 96 patients after TEVAR. Two preoperative factors showed strong associations with LAE according to the multivariable logistic regression analysis: preoperative partial thrombosis of the FL (OR = 10.989 [2.295-48.403]; p = 0.002) and the maximum descending aortic diameter (OR = 1.385 [1.100-1.743] per mm increase; p = 0.006).

CONCLUSIONS

Preoperative partial thrombosis of the FL and an increase in the maximum aortic diameter are strongly associated with late aortic expansion. Additional interventions of the FL may help to improve the prognosis of patients with the high risk of late aortic expansion.

Reconstruction of the accessory renal artery with autogenous vessels in aortic hybrid surgery: A case report

OBJECTIVE

Accessory renal artery (ARA) is a common variant of renal vessels. Currently, there are some controversies about reconstruction strategy and few cases reported in the literature. Individualized treatment should be carried out according to preoperative renal function evaluation and technical level.

METHODS

In this paper, a 50-year-old male patient was reported, who developed a dissecting aneurysm after thoracic endovascular aortic repair (TEVAR) and needed further intervention. Imaging showed that the left kidney was supplied by bilateral renal artery (false lumens), and there were left renal malperfusion complicated with abnormal renal function.

RESULTS

Autologous blood vessels were used to successfully reconstruct ARA with during hybrid surgery. Renal perfusion and renal function recovered rapidly after operation. There was no abnormality in renal indexes after 3 months follow-up.

CONCLUSION

It is beneficial and necessary to reconstruct ARA for patients with renal malperfusion or abnormal renal function before operation.

The Necessity to Seal the Re-Entry Tears of Aortic Dissection After TEVAR: A Hemodynamic Indicator

Thoracic endovascular aortic repair (TEVAR) is a common treatment for Stanford type B aortic dissection (TBAD). However, re-entry tears might be found distal to the stented region which transports blood between the true and false lumens. Sealing the re-entry tears, especially for the thoracic tears, could further reduce blood perfusion to the false lumen; however, it might also bring risks by re-intervention or surgery. Wise determination of the necessity to seal the re-entry tears is needed. In this study, patient-specific models of TBAD were reconstructed, and the modified models were established by virtually excluding the thoracic re-entries. Computational hemodynamics was investigated, and the variation of the functional index and first balance position (FBP) of the luminal pressure difference, due to the sealing of the re-entries, was reported. The results showed that the direction of the net flow through the unstented thoracic re-entries varied among cases. Excluding the re-entries with the net flow toward the false lumen may induce the FBP moving distally and the relative particle residence time increasing in the false lumen. This study preliminarily demonstrated that the hemodynamic status of the re-entry tears might serve as an indicator to the necessity of sealing. By quantifying the through-tear flow exchange and shift of FBP, one can predict the hemodynamic benefit by sealing the thoracic re-entries and thus wisely determine the necessity of further interventional management.

Clinical Results and Aortic Remodeling After Endovascular Treatment for Complicated Type B Aortic Dissection With the “Fabulous” Stent System

Objective

To report the clinical outcomes and aortic remodeling after the implantation of a self-developed, biomechanically optimized, two-stage thoracic stent system named Fabulous.

Background

Given the efficacy of the PETTICOAT concept, the benefits of Fabulous and the behavior of remodeling in different segments need further investigation.

Methods

This is a prospective and multicenter study. From 2017 to 2019, 145 patients (mean age, 56.6 years; 88.3% male) from 14 centers were included in this cohort. The clinical results and core laboratory results were from a central electronic data capture system. Computed tomographic angiography was performed preoperatively, 1 month, 6 months and yearly thereafter and was used for volumetric analysis by 3mensio (Bilthoven, The Netherlands). After the 1-year follow-up, 97.2 and 87.6% of the clinical and imaging results of the eligible patients were available.

Results

Both stent grafts and bare stents were successfully delivered in place in 100% of the patients. The 30-day mortality and 1-year freedom from all-cause mortality were 2.1 and 96.6%, respectively. The incidence of entry flow was 11.7% at 30 days and 6.2% at 365 days. No cases of stent-induced new entry (SINE) or reintervention were observed. After the 1-year follow-up, the true lumen/overall volume ratio reached 88%. The following subdivided segment volume changes were recorded: stent graft segment TL +56%; FL −92%, bare stent segment TL +32%; FL −75%, and there were no significant changes in the visceral segment.

Conclusions

These outcomes indicated that there were favorable clinical benefits of Fabulous stent system. This device achieved a low short-term mortality and a low incidence of reintervention. In addition, patients undergoing Fabulous stent system implantation showed remodeling both on descending aorta and on the distal aorta. The volume changes in the TL and FL varied in the different segments. The long-term follow-up is still ongoing.

Spontaneous Isolated Dissection of Iliac Artery Treated with Endovascular Repair: A Case Report

Spontaneous isolated dissection of the iliac artery (SID-IA) is a rare pathologic condition. The predisposing factors and best treatment strategies are still being debated. We present the case of a 59-year-old male with acute right lower limb ischemia characterized by the sudden occurrence of rest pain, hypoesthesia, and paresis. Angiography showed SID-IA extending down to the femoral bifurcation. The patient had no risk factors for SID-IA; however, he survived an electrocution and had arterial hypertension at admission. Endovascular revascularization was successfully performed, with complete restoration of limb blood flow and remission of symptoms. Follow-up ultrasonography at 1 year confirmed stent patency and absence of clinical symptoms. Endovascular stenting is a good therapeutic option for symptomatic SID-IA without rupture.

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

Purpose

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

Materials and Methods

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

Results

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

Conclusion

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

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.

Short Term Outcomes of Distal Extended EndoVascular Aortic Repair (DEEVAR) Petticoat in Acute and Subacute Complicated Type B Aortic Dissection

OBJECTIVE

The aim of this study was to evaluate the peri-operative and short term results of institutional experience with the Distal Extended EndoVascular Aortic Repair PETTICOAT (DEEVAR PETTICOAT) procedure.

METHODS

This was a single centre, observational study. From January 2015 to December 2019, 53 patients were admitted to the institution for treatment of acute and subacute complicated type B aortic dissection. Among them, data on 16 patients deemed suitable for a PETTICOAT procedure extended at infrarenal and iliac level by means of a bifurcated endograft were prospectively collected. Patients with persistent pain, visceral or lower limb malperfusion, true lumen collapse, and distal extension with computed tomography angiography (CTA) evidence of entry tears in the infrarenal or iliac zone were included. A CTA scan was performed in all patients at the baseline, before hospital discharge and then at six and 12 months post-operatively to assess aortic remodelling. Complete aortic remodelling was defined as stable aortic size (maximum enlargement < 5 mm) with complete true lumen re-expansion and complete false lumen exclusion or disappearance.

RESULTS

Technical success was obtained in all patients. One patient (7%) had intra-operative infrarenal aortic rupture during balloon dilation of the distal end of the bare stent, successfully treated by deployment of a bifurcated endograft. Additional covered stenting of the visceral arteries was necessary in nine patients (56%) and malperfusion resolved immediately in all cases. There were no spinal cord ischaemia or other peri-procedural complications, and no post-operative death, stroke, paraplegia/paraparesis, or acute renal failure was observed. Follow up ranged from one month to 24 months (median 7.5 months). One patient (7%) with a history of drug abuse died from sepsis. At the last CTA check, all patients showed complete remodelling of the thoraco-abdominal aorta and iliac arteries without vessel enlargement.

CONCLUSION

The present findings suggest that the DEEVAR PETTICOAT procedure provides effective sealing of all distal tears without increased risk of major peri-procedural complications. Further studies with larger number of patients and longer follow up are needed to confirm the safety and durability of this technique.

Impact of body mass index on early and mid-term outcomes after surgery for acute Stanford type A aortic dissection

Background

Obesity is dramatically increasing worldwide, and more obese patients may develop aortic dissection and present for surgical repair. The study aims to analyse the impact of body mass index (BMI) on surgical outcomes in patients with acute Stanford type A aortic dissection (ATAAD).

Methods

From January 2017 to June 2019, the clinical data of 268 ATAAD patients in a single centre were retrospectively reviewed. They were divided into three groups based on the BMI: normal weight (BMI 18.5 to < 25 kg/m², n = 110), overweight (BMI 25 to < 30 kg/m², n = 114) and obese (BMI ≥30 kg/m², n = 44).

Results

There was no statistical difference among the three groups in terms of the composite adverse events including 30-day mortality, stroke, paraplegia, renal failure, hepatic failure, reintubation or tracheotomy and low cardiac output syndrome (20.9% vs 21.9% vs 18.2% for normal, overweight and obese, respectively; P = 0.882). No significant difference was found in the mid-term survival among the three groups. The proportion of prolonged ventilation was highest in the obese group followed by the overweight and normal groups (59.1% vs 45.6% vs 34.5%, respectively; P = 0.017). Multivariable logistic regression analysis suggested that BMI was not associated with the composite adverse events, while BMI ≥30 kg/m² was an independent risk factor for prolonged ventilation (OR 2.261; 95% CI 1.056–4.838; P = 0.036).

Conclusions

BMI had no effect on the early major adverse outcomes and mid-term survival after surgery for ATAAD. Satisfactory surgical outcomes can be obtained in patients with ATAAD at all weights.

The characteristics of distal tears affect false lumen thrombosis rate after thoracic endovascular aortic repair for acute type B dissection

OBJECTIVES

A low false lumen thrombosis rate (FLTR) is common in patients with type B aortic dissection after they have undergone thoracic endovascular aortic repair, which indicates a poor long-term prognosis. This study aimed to establish a quantitative linear regression model to predict false lumen (FL) thrombosis accurately using morphological parameters.

METHODS

In this retrospective study, we included 59 patients diagnosed with acute type B aortic dissection between 2014 and 2017. Morphological parameters were measured. Univariable and multivariable linear regression analyses were performed, and a linear regression model relating FLTR with the number of re-entry tears was proposed. Ten patients were further chosen to validate the linear relationship, and idealized aortic dissection models were adopted for haemodynamic analysis.

RESULTS

Only the total area and number of re-entry tears were negatively correlated with FL thrombosis (P < 0.001). Moreover, based on the univariable regression, the number of re-entry tears played a more crucial role in FLTR (R2 = 0.509 vs R2 = 0.298), and the linear relationship model was created as follows: thrombosis rate (%) = -11.25 × distal tear number + 105.24. This model was perfectly matched in 10 patients (concordance correlation coefficient = 0.880, P = 0.947). Moreover, when the total area of re-entry tears was constant, the net blood flow increased rapidly with an increase in the tear count.

CONCLUSIONS

The number of re-entry tears could be a crucial related factor of FL thrombosis; the larger the number of re-entry tears is, the lower the possibility of thrombosis is.

Prediction of Distal Aortic Enlargement after Proximal Repair of Aortic Dissection Using Machine Learning

OBJECTIVES

This study aimed to construct a risk prediction model for distal aortic enlargement in patients with type B aortic dissection (TBAD) treated with proximal thoracic endovascular aortic repair (TEVAR).

METHODS

From June 2010 to June 2016, patients with TBAD who underwent proximal TEVAR were retrospectively analyzed. A total of 38 clinical and imaging variables were collected. Univariable logistic regression was conducted to explore potential risk factors associated with distal aortic enlargement. Elastic net regression was employed to select significantly influential variables. Then, machine learning algorithms (logistic regression (LR), artificial neutral network (ANN), random forest and support vector machine) were applied to build risk prediction models. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity were used to evaluate the performance of these models.

RESULTS

A total of 503 patients were enrolled in this study. During the follow-up, 105 (20.9%) patients were identified as having distal aortic enlargement, and 69 (13.7%) patients were found to have distal aortic aneurysm formation. Five patients were identified with aortic rupture. True lumen collapse and multi-false lumens were two potential risk factors for distal aortic enlargement after proximal repair of TBAD. The LR model performed the best in predicting distal aortic enlargement, with the highest sensitivity (96.7%) and an AUC of 0.773. The best model for predicting distal aneurysm formation was the ANN model, which yielded the highest AUC (0.876) and a specificity of 79.1%.

CONCLUSIONS

Machine learning approaches can produce accurate predictions of distal aortic enlargement after proximal repair of TBAD, which potentially benefits subsequent management.

Influence of Distal Re-entry Tears on False Lumen Thrombosis After Thoracic Endovascular Aortic Repair in Type B Aortic Dissection Patients: A Computational Fluid Dynamics Simulation

PURPOSE

Distal re-entry tears play a significant role in false lumen (FL) thrombosis, which will strongly affect the postoperative long-term survival of patients with type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR). This study aimed to investigate the influence of a peculiar morphological parameter of the residual re-entry tears in TBAD patients after TEVAR on long-term FL thrombosis using the computational fluid dynamics.

METHODS

Ideal population-based three-dimensional models of post-operative TBAD were established. Numerical simulation was performed to investigate the hemodynamic differences caused by different tear features, including the tear count, the maximum distance between tears, and the tear area.

RESULTS

Although the low relative residence time (RRT) area did not change significantly when the tear distance was fixed, the area of oscillatory shear index (OSI) > 0.45 and endothelial cell activation potential (ECAP) > 1.5 decreased significantly with the tear count and area increased and a dramatic increase in blood flow into the FL was also observed. When tear count and total area were fixed, for each 10-mm increase in the maximum distance between tears, the area of low RRT in the FL increased significantly, while the average pressure difference increased by 10.85%.

CONCLUSION

The different morphology of the re-entry tears had different effects on the thrombosis-related hemodynamic parameters in FL following TEVAR. and the number of re-entry tears was most crucial to the potential thrombosis in the post-TEVAR FL of TBAD patients.

False Lumen Stent-Grafts for Repair of Postdissection Aortic Aneurysms

PURPOSE

To evaluate the safety and efficacy of false lumen (FL) stent-grafts in the treatment of postdissection aortic aneurysms.

MATERIALS AND METHODS

Eleven patients who underwent endovascular repair using FL stent-grafts from January 2016 to June 2019 were included. Among them, 2 patients had a prior history of type A aortic dissection, whereas 9 had undergone a prior endovascular repair for type B aortic dissection. Computed tomography angiography was performed to evaluate the reintervention and technical success rate, aortic remodeling, and other related aortic complications.

RESULTS

The mean age of patients was 55.6 ± 10.4 years. Technical success was achieved in all patients, and neither early mortality nor paralysis occurred. In total, 8 visceral branch arteries originating from the FL were reconstructed. The true lumen areas at the celiac axis, superior mesenteric artery, renal artery, and abdominal aortic bifurcation were significantly increased from 230.1 mm² to 312.3 mm², 212.1 mm² to 277.5 mm², 209.1 mm² to 291.6 mm², and 214.4 mm² to 300.6 mm², respectively (P < .05). The total diameter of the aorta at the 4 designated levels was stable or had shrunk in all patients. At a mean follow-up of 18.9 ± 7.6 months, 1 patient received re-intervention owing to iliac stent-graft occlusion. No aortic-related mortality occurred.

CONCLUSIONS

FL stent-grafts can safely and effectively treat patients with postdissection aortic aneurysms. This strategy can be used to promote thrombosis of the FL and aortic remodeling. A larger sample and an extended follow-up period are needed to produce more conclusive results.

Extended thoracic endovascular aortic repair for residual aortic dissection after type A aortic dissection repair

OBJECTIVE

We investigated the outcomes of extended coverage of the descending thoracic aorta by thoracic endovascular aortic repair (TEVAR) for residual chronic type B aortic dissection after type A aortic dissection (TAAD) repair.

METHODS

From November 2015 to August 2020, 36 patients underwent extended TEVAR for residual intimal tear after TAAD repair. We specifically investigated the methods and outcomes of this procedure.

RESULTS

TEVAR consisted of isolated TEVARs (n = 29), single-vessel debranching TEVAR (6), and two-vessel debranching TEVAR (1). The mean time from TAAD repair to TEVAR was 27 ± 33 months (2-86 months). The TEVAR devices used were Valiant (28 cases), GORETAG (4), Relay plus (2), and TX2 (2). Technical success of TEVAR was 100%. The distal ends of the stent grafts were T 8 (1 case), T 9 (5), T 10 (6), T 11 (9), and T 12 (15), with an average of T 11 ± 1. The average length of hospital stay after TEVAR was 9 ± 3 days (5-17 days). There were no surgical/hospital deaths or complications. The average postoperative follow-up period was 21 ± 15 months without death or reintervention.

CONCLUSIONS

The short-term outcomes of extended TEVAR for residual chronic type B aortic dissection after TAAD repair were acceptable without perioperative SCI. Aggressive descending thoracic aorta coverage may prevent aortic events, and extended TEVAR may be a preemptive treatment for the downstream aorta. Mid- to long-term results should be clarified.

Endovascular strategies for post-dissection aortic aneurysm (PDAA)

Residual patent false lumen (FL) after type B aortic dissection (TBAD) repair is independently associated with poor long-term survival. Open surgery and endovascular repair result in good clinical outcomes in patients with AD. However, both treatments focus on proximal dissection but not distal dissection. About 13.4–62.5% of these patients present with different degrees of distal aneurysmal dilatation after primary repair. Although open surgery is the first-choice treatment for post-dissection aortic aneurysm (PDAA), there is a need for high technical demand since open surgery is associated with high mortality and morbidity. As a treatment strategy with minimal invasion, endovascular repair shows early benefits and low morbidity. For PDAA, the narrow true lumen (TL), rigid initial flap and branch arteries originating from FL have increased difficulties in operation. The aim of endovascular treatment is to promote FL thrombosis and aortic remodeling. Endovascular repair includes intervention from FL and TL sides. TL intervention techniques (parallel stent-graft, branched and fenestrated stent-graft among others) have been proven to be safe and effective in PDAA. Other FL intervention techniques that have been used in selected patients include FL embolization and candy-plug techniques. This article introduces available endovascular techniques and their outcomes for the treatment of PDAA.

Preclinical evaluation of an endovascular sealing device for distal re-entry tears in type B aortic dissection in a porcine model

OBJECTIVES

The objective of present study was to evaluate the feasibility and safety of a novel endovascular sealing device for distal re-entry tears in type B aortic dissection in a porcine model.

BACKGROUND

Distal re-entry tears are a well-recognized risk factor for unfavorable aortic remodeling after thoracic endovascular aortic repair. However, there is currently no device for sealing a distal re-entry tear.

METHODS

We implanted the ENDOPATCH device (Weiqiang Medical, Hangzhou, China) in 15 pigs (40-50 kg) under angiographic guidance. The device can be retrieved and repositioned with an 8-10 French sheath. All pigs were assessed using angiography before sacrifice 1- (n = 1), 3- (n = 1), and 6 months (n = 13) after implantation, which was followed by gross specimen evaluation and histological examination of harvested tissues.

RESULTS

The ENDOPATCH device was successfully implanted in all 15 pigs. The mean disk diameter of the implant was 10.3 ± 1.7 mm, and the chosen device was 4.4 ± 0.9 mm larger than the measured maximum diameter of the fistula. No device migration or leakage was observed angiographically, before sacrifice. An organized thrombus on the disk surface was found in the inferior vena cava of one pig. Complete sealing of the fistula was confirmed by gross and microscopic examinations in all pigs.

CONCLUSIONS

Our results indicated that the ENDOPATCH device is feasible and safe in a porcine model. Human studies are needed to evaluate the safety and efficacy of the ENDOPATCH.

The Impact of a Reentry Tear After Open Repair of Nonsyndromic Acute Type I Aortic Dissection

BACKGROUND

The role of a reentry tear in the descending thoracic aorta (DTA) after repair of acute aortic dissection is not well known. We therefore investigated the impact of reentry tear location on late aorta reintervention and the aortic expansion rate after open repair of acute type I aortic dissection.

METHODS

We analyzed 309 nonsyndromic acute type I aortic dissection patients who were treated with a repair to the proximal aorta between 1994 and 2017. The locations of reentry tears, identified with predischarge computed tomography, were the proximal DTA in 119 patients (38.5%), distal DTA in 78 (25.2%), and abdominal aorta in 129 (41.7%). Patients who had a proximal DTA reentry tear were defined as the PDR group (119 [38.5%]), and the others were defined as the non-PDR group (190 [61.5%]).

RESULTS

The 15-year freedom from aorta reintervention was significantly lower in the PDR group (51.5% ± 0.7% vs 90.4% ± 4.4%, P < .001). The aortic expansion rates of the proximal DTA (7.6 ± 16.1 mm/y vs 0.1 ± 2.5 mm/y, P < .001) and distal DTA (6.8 ± 15.5 mm/y vs 0.3 ± 3.1 mm/y, P < .001) were significantly higher in the PDR group. The 15-year freedom from significant aortic expansion was significantly lower in the PDR group (34.6% ± 6.9% vs 83.6% ± 7.9%, P < .001). Multivariate analysis showed that a proximal DTA reentry tear was an independent risk factor for aorta reintervention (hazard ratio, 4.955; 95% confidence interval, 1.691-14.523; P = .004) and significant aortic expansion (HR, 4.214; 95% CI, 1.691-10.498; P = .002).

CONCLUSIONS

A proximally located DTA reentry tear was associated with an increased risk of late aorta reintervention and distal aortic dilatation.

Predictor of false lumen thrombosis after thoracic endovascular aortic repair for type B dissection

OBJECTIVE

Thoracic endovascular aortic repair of type B aortic dissection initiates thrombosis in the false lumen, which eventually results in aortic remodeling. We aimed to determine whether the false lumen thrombosis rate (FLTR) after thoracic endovascular aortic repair can be accurately predicted by an index that expresses the degree of aortic arch angulation.

METHODS

The geometry of 48 patients with acute type B aortic dissection (mean age, 48 years) after thoracic endovascular aortic repair was reconstructed from postoperative computed tomography images. We introduced a novel angle-the degree of question mark (φ)-to indicate the aortic morphology. Moreover, how aortic angulation influenced the FLTR was investigated based on hemodynamic parameters. Finally, a predicted mathematical model relating FLTR to aortic angulation was proposed, and 10 patients were chosen to validate the model.

RESULTS

The degree of question mark shape was shown to negatively correlate with FLTR (n = 38; P < .001; R = -0.661), and the linear relationship model was created as follows: FLTR (%) = -1.955 × φ + 168.24 (R² = 0.437; P < .001). In addition, the net flow rate to the false lumen significantly increased with the increase of the degree of the question mark shape of the aorta. Furthermore, the difference and concordance of the proposed prediction model were perfectly validated in the remaining 10 patients using paired-sample t test and the concordance correlation coefficient.

CONCLUSIONS

The size of the question mark shape may be a good predictor for FLTR of acute type B aortic dissection following thoracic endovascular aortic repair. The higher the degrees of the question mark, the less likely it was to form a complete thrombus.

A Promising Treatment of Distal Entry Tears Located in Branched Area of Abdominal Aorta With Coil-Stent Tear Occlusion Device: an Animal Experiment

This study aims to evaluate the effect of coil-stent tear occlusion device in treating entry tears located in branched area of abdominal aorta. An abdominal aortic dissection animal model was constructed by mesh suturing method. The animal models were treated by the occlusion device and were evaluated by computed tomography angiography (CTA) 1 month later. Eighteen pigs were adopted in the abdominal aortic dissection modeling experiment, two of them died of cardiopulmonary arrest during the operation. Sixteen models survived, two of them were found complete false lumen thrombosis by CTA 3 days after the operation. The false lumen kept patency in the remaining 14 cases which were then implanted with the occlusion device. The procedure was successful in 13 cases except for one. The coil-stent tear occlusion device provides a novel method for tears located in the branched area of abdominal aorta, and is worth of further study.