Thoracic endovascular aneurysm repair for complicated type B aortic dissection

Interventions in Acute or Subacute Phase for Type B Aortic Dissection

The treatment strategy for acute and subacute Stanford type B aortic dissection has changed significantly since the advent of thoracic endovascular aortic repair (TEVAR). Indication for invasive treatment: In addition to the conventional complicated cases (rupture or malperfusion case), the indication for invasive treatment now includes cases with refractory hypertension, persistent or recurrent pain, large aortic diameter, and other conditions that are considered to have a poor prognosis with conservative treatment. Treatment methods: TEVAR is the first choice for acute, subacute, and early chronic-stage treatment, and when this is not possible, other techniques (fenestration and graft replacement) are chosen. Treatment timing: The timing of invasive treatment should be emergent in life-threatening conditions (for rupture or malperfusion case) and immediate in symptomatic cases, while in other cases, preemptive TEVAR is considered appropriate on a scheduled timing within 6 months of onset. (This is a translation of Jpn J Vasc Surg 2023; 32: 157-163.).

Growth and remodeling of the dissected membrane in an idealized dissected aorta model

While transitioning from the acute to chronic phase, the wall of a dissected aorta often expands in diameter and adaptations in thickness and microstructure take place in the dissected membrane. Including the mechanisms, leading to these changes, in a computational model is expected to improve the accuracy of predictions of the long-term complications and optimal treatment timing of dissection patients. An idealized dissected wall was modeled to represent the elastin and collagen production and/or degradation imposed by stress- and inflammation-mediated growth and remodeling, using the homogenized constrained mixture theory. As no optimal growth and remodeling parameters have been defined for aortic dissections, a Latin hypercube sampling with 1000 parameter combinations was assessed for four inflammation patterns, with a varying spatial extent (full/local) and temporal evolution (permanent/transient). The dissected membrane thickening and microstructure was considered together with the diameter expansion over a period of 90 days. The highest success rate was found for the transient inflammation patterns, with about 15% of the samples leading to converged solutions after 90 days. Clinically observed thickening rates were found for 2-4% of the transient inflammation samples, which represented median total diameter expansion rates of about 5 mm/year. The dissected membrane microstructure showed an elastin decrease and, in most cases, a collagen increase. In conclusion, the model with the transient inflammation pattern allowed the reproduction of clinically observed dissected membrane thickening rates, diameter expansion rates and adaptations in microstructure, thus providing guidance in reducing the parameter space in growth and remodeling models of aortic dissections.

Uncertainty quantification of the wall thickness and stiffness in an idealized dissected aorta

Personalized treatment informed by computational models has the potential to markedly improve the outcome for patients with a type B aortic dissection. However, existing computational models of dissected walls significantly simplify the characteristic false lumen, tears and/or material behavior. Moreover, the patient-specific wall thickness and stiffness cannot be accurately captured non-invasively in clinical practice, which inevitably leads to assumptions in these wall models. It is important to evaluate the impact of the corresponding uncertainty on the predicted wall deformations and stress, which are both key outcome indicators for treatment optimization. Therefore, a physiology-inspired finite element framework was proposed to model the wall deformation and stress of a type B aortic dissection at diastolic and systolic pressure. Based on this framework, 300 finite element analyses, sampled with a Latin hypercube, were performed to assess the global uncertainty, introduced by 4 uncertain wall thickness and stiffness input parameters, on 4 displacement and stress output parameters. The specific impact of each input parameter was estimated using Gaussian process regression, as surrogate model of the finite element framework, and a δ moment-independent analysis. The global uncertainty analysis indicated minor differences between the uncertainty at diastolic and systolic pressure. For all output parameters, the 4th quartile contained the major fraction of the uncertainty. The parameter-specific uncertainty analysis elucidated that the material stiffness and relative thickness of the dissected membrane were the respective main determinants of the wall deformation and stress. The uncertainty analysis provides insight into the effect of uncertain wall thickness and stiffness parameters on the predicted deformation and stress. Moreover, it emphasizes the need for probabilistic rather than deterministic predictions for clinical decision making in aortic dissections.

Feasibility of Total Endovascular Repair of the Aorta in Patients with Acute Type A Aortic Dissection: Morphological Analysis of 119 Patients

(1) Background: This study aimed to morphologically analyze acute type A aortic dissection (aTAAD) patients for potential endovascular treatment candidates. The objective was to specify requirements for aTAAD endovascular devices. (2) Methods: A single-center retrospective analysis included aTAAD patients who underwent open surgical repair between November 2005 and December 2020. Preoperative CTA scans were used for morphological analysis, assessing endovascular repair eligibility. Statistical tests were performed. (3) Results: A total of 129 patients with aTAAD were studied, with 119 included. Entry tear (ET) locations were identified, mainly in the aortic root, 20 mm above the sinotubular junction (STJ) and within the ascending aorta (20 mm above STJ to -20 mm before the brachiocephalic trunk). Endovascular treatment was deemed feasible for 36 patients, with suggested solutions for the aortic arch and descending aorta. Significant differences were observed between eligible and noneligible groups for aortic diameter, false lumen diameter, distance between STJ and entry tear, and more. Dissection extension showed no significant difference. (4) Conclusions: Morphological analysis identified potential aTAAD candidates for endovascular treatment, highlighting differences between eligible and noneligible morphologies. This study offers insights for implementing endovascular approaches in aTAAD treatment and emphasizes the need for research and standardized protocols.

Mid-term outcomes of left subclavian artery revascularization with Castor stent graft in treatment of type B aortic dissection in left subclavian artery

Background

Here we analyzed mid-term data of thoracic endovascular aneurysm repair (TEVAR) surgery with Castor single-branched stent graft placement for the management of Stanford type B aortic dissection (STBAD) involving the left subclavian artery (LSA).

Methods

Between April 2014 and February 2019, 32 patients with STBAD involving a Castor single-branched stent graft were included. We analyzed their outcomes, including technical success rate (TSR), surgical duration (SD), presence of ischemia, perioperative complications, LSA patency, and survival rate (SR), using computed tomography angiography and clinical evaluation during mid-term follow-up.

Results

The mean patient age was 54.63 ​± ​12.37 years (range, 36-83 years). The TSR was 96.88% (n ​= ​31/32). The mean SD was 87.44 ​± ​10.89 with a mean contrast volume of 125.31 ​± ​19.30 ​mL. No neurological complications or deaths occurred during the study period. The patients had a mean hospital stay of 7.84 ​± ​3.20 days. At a mean follow-up of 68.78 ​± ​11.26 months, four non-aortic deaths (12.5%) were observed. The LSA patency rate was 100% (n ​= ​28/28). There was only one case of type I endoleak immediately after surgery (3.12%) (type I from LSA). However, none of the patients experienced type II endoleaks, and there were no cases of retrograde type A aortic dissection or stent graft-driven new distal entry. Finally, all patients exhibited good LSA patency.

Conclusion

TEVAR using a Castor single-branched stent graft may be a highly feasible and efficient procedure for the management of STBAD involving the LSA.

Risk Factors Associated with Poor Prognosis in Patients with Stanford Type B Aortic Dissection after Thoracic Endovascular Aortic Repair

BACKGROUND

The aim of the study was to analyze the clinical characteristics of patients with Stanford type B aortic dissection (TBAD) and risk factors for poor prognosis after thoracic endovascular aortic repair (TEVAR).

METHODS

Clinical records for patients with TBAD presenting to a medical center between March 1, 2012 and July 31, 2020 were reviewed. Clinical data including demographics, comorbidities, and postoperative complications were obtained from electronic medical records. Comparative analysis and subgroup analysis were performed. A logistic regression model was used to analyze prognostic factors in patients with TBAD after TEVAR.

RESULTS

TEVAR was performed on all 170 patients with TBAD, and poor prognosis was identified in 28.2% (48/170) of cases. Patients with a poor prognosis were younger (38.5 [32.0, 53.8] years vs. 55.0 [48.0, 62.0] years, P < 0.001), had higher systolic blood pressure (SBP) (138.5 [127.8, 152.8] mm Hg vs. 132.0 [120.8, 145.3] mm Hg, P = 0.013) and more complicated aortic dissection patients (19 [60.4] vs. 71 [41.8], P = 0.029) than those without a poor prognosis. According to the results of binary logic regression analysis, the possibility of a poor prognosis after TEVAR decreased with each 10 years increase in age (odds ratio: 0.464, 95% confidence interval: 0.327-0.658, P < 0.001).

CONCLUSIONS

There is an association between younger age and a poor prognosis after TEVAR in patients with TBAD, with the condition that those with poor prognoses have higher SBP and more complicated cases. In younger patients, postoperative follow-up should be more frequent, and complications should be managed in time.

A Comparison of Clinical Outcomes of Endovascular Repair Versus Open Surgery for Ruptured Descending Thoracic Aorta

OBJECTIVE

The comparisons between thoracic endovascular aortic repair for ruptured thoracic aorta (TEVAR) and open surgery (OS) have not been well documented, although both procedures have been widely utilized. We performed a systematic review and meta-analysis to investigate the effectiveness and safety between TEVAR and OS in the repair of ruptured descending thoracic aorta.

METHODS

PubMed, Embase, and Cochrane Library databases were searched to find relevant studies to assess TEVAR and OS outcomes. The comparative parameters were perioperative mortality (30 day/in-hospital), 1 year mortality, paraplegia or paraparesis, renal insufficiency, stroke, pulmonary embolism, re-intervention rate, pulmonary complications, and cardiac complications. A fixed-effects model was applied to calculate the odds ratio (OR) with a 95% confidence interval (CI) on pooled outcomes from different studies.

RESULTS

Eighteen observational trials involving 2088 patients were evaluated (TEVAR=560; OS=1528). Meta-analysis showed that TEVAR in repairing the ruptured descending thoracic aorta was associated with lower perioperative mortality (OR=0.47; 95% CI: 0.34-0.66; p<0.01), 1 year mortality (OR=0.46; 95% CI: 0.29-0.75; p<0.01), renal insufficiency incidence (OR=0.56; 95% CI: 0.33-0.93; p=0.03), and pulmonary complications (OR=0.69; 95% CI: 0.52-0.92; p=0.01) when compared with OS. There was no significant difference between TEVAR and OS in terms of paraplegia, stroke, pulmonary embolism, cardiac complications, and early re-intervention rates. However, the late re-intervention rate was higher in the TEVAR group than that in the OS group.

CONCLUSIONS

When repairing the ruptured descending thoracic aorta, TEVAR may be performed rapidly and safely. TEVAR is associated with lower rates of perioperative morbidity and early postoperative complications than OS.

Predicting reintervention after thoracic endovascular aortic repair of Stanford type B aortic dissection using machine learning

OBJECTIVES

To construct models for predicting reintervention after thoracic endovascular aortic repair (TEVAR) of Stanford type B aortic dissection (TBAD).

METHODS

A total of 192 TBAD patients who underwent TEVAR were included; 68 (35.4%) had indications for reintervention. Clinical characteristics, aorta characteristics on pre- and postoperative computed tomography angiography, and aorta characteristics on immediate postoperative aortic digital subtraction angiography were collected. The least absolute shrinkage and selection operator (LASSO) regression was applied to identify the risk factors for reintervention. Eight classifiers were used for modeling. The models were trained on 100 train-validation random splits with a ratio of 2:1. The performance was evaluated by the receiver operating characteristic curve.

RESULTS

Seven predictors of reintervention were identified, including maximum false lumen diameter, aortic diameter measured at the level of approximately 15 mm distal to the left subclavian artery, aortic diameter measured at the level of the diaphragm, false lumen diameter measured at the level of the celiac artery, number of bare-metal and covered stents, number of bare-metal stents, and residual perfusion of the false lumen. Logistic regression (LR) yielded the highest performance, with an area under the curve of 0.802. A nomogram built for clinical use showed good calibration. The cutoff value for dividing patients into low- and high-risk subgroups was 0.413. Kaplan-Meier curves showed that the overall survival of high-risk patients was significantly shorter than that of low-risk patients (both p < 0.05).

CONCLUSION

Our nomogram could predict the reintervention after TEVAR in patients with TBAD, which may facilitate patient selection and surveillance strategies.

KEY POINTS

• Seven risk factors of reintervention after TEVAR of TBAD were identified for modeling. • Logistic regression performed best in predicting reintervention with an AUC of 0.802. • Patients with a high risk of reintervention had shorter OS than those with a low risk.

3D Morphologic Findings Before and After Thoracic Endovascular Aortic Repair for Type B Aortic Dissection

BACKGROUND

Stanford type-B aortic dissection (TBAD) is commonly treated by thoracic endovascular aortic repair (TEVAR). Usually, the implanted stent-grafts will not cover the entire dissection-affected region for those patients with dissection extending beyond the thoracic aorta, thus the fate of the uncovered aortic segment is uncertain. This study used 3-dimensional measurement of aortic morphological changes to classify the different remodeling effects of TBAD patients after TEVAR, and hypothesized that not only initial morphological features, but also their change over time at follow-up are associated with the remodeling.

METHODS

Forty-one TBAD patients underwent TEVAR and CT-angiography before and after the intervention (twice or more follow-ups) were included in this study. According to the false-lumen volume variations post-TEVAR, patients who had abdominal aortic expansion at the second follow-up were classified into the Enlarged (n =12, 29%) and remaining into the Stable group (n = 29, 71%). 3D morphological parameters were extracted on precise reconstruction of imaging datasets. Statistical differences in 3D morphological parameters over time between the 2 groups and the relationship among these parameters were analyzed.

RESULTS

In the Enlarged group, the number of all tears before TEVAR was significantly higher (P = 0.022), and the size of all tears at the first and second follow-up post-TEVAR were significantly higher than that in the Stable group (P = 0.008 and P = 0.007). The location of the primary tear was significantly higher (P = 0.031) in the Stable group. The cross-sectional analysis of several slices below the primary tear before TEVAR shows different shape features of the false lumen in the Stable (cone-like) and Enlarged (hourglass-like) groups. The number of tears before TEVAR has a positive correlation with the post-TEVAR development of dissection (r = 0.683, P = 0.00).

CONCLUSION

The results in this study indicated that the TBAD patients with larger tear areas, more re-entry tears and with the primary tear proximal to the arch would face a higher risk of negative remodeling after TEVAR.

Improved Remodeling With TEVAR and Distal Bare-Metal Stent in Acute Complicated Type B Dissection

BACKGROUND

The ASSIST (A multicentre Study in Survivors of type B aortic dissection undergoing Stenting) study compared both 1-year outcomes and evolution of true and false lumen (eg, remodeling) in patients with complicated type B aortic dissection subjected to thoracic endovascular aortic repair (TEVAR) with distal true lumen scaffolding by self-expanding nitinol open stent in comparison with TEVAR alone.

METHODS

The ASSIST study was a multicenter prospective single-arm study comparing clinical and imaging data from 39 consecutive patients (59.4 ± 13 years of age) who received TEVAR and the JOTEC E-XL open stent with data from matched control subjects treated with TEVAR alone based on 1:1 propensity score matching. Clinical data were collected by an independent Contract Research Organization (CRO) and computed tomography images were subjected to blinded core-lab analysis.

RESULTS

There were no differences in baseline demographics, clinical profiles, morphological data, procedural details, and in-hospital and 1-year outcomes between groups. Differences emerged with regard to evolution of both true lumen distal to stent graft, false lumen over the entire length of dissection, and remodeling (P < .001). At 1 year, TEVAR with the E-XL stent revealed false lumen thrombosis at the level of celiac trunk in 53.8% vs 17.9% with TEVAR alone (P = .004). Kaplan-Meier survival analysis indicated favorable clinical outcomes with the additional E-XL stent.

CONCLUSIONS

TEVAR for acute complicated type B aortic dissection proved to be safe and promoted remodeling of the stent grafted thoracic aorta. Additional scaffolding of the true lumen distal to TEVAR with a self-expanding stent supported distal true lumen expansion, false lumen regression, and thrombosis, with evidence of improved distal remodeling at 1 year.

Mid- and Long-Term Effects of Endovascular Surgery and Hybrid Procedures for Complex Aortic Diseases

Objective

To assess the efficacy and short- and mid-term results of endovascular surgery and hybrid surgical procedures in treatment of complex aortic dissection.

Methods

Clinical data of 90 patients with complex aortic dissection admitted from June 2012 to June 2018 were retrospectively analyzed. Among the patients, 60 cases were male and 30 cases were female, and their ages were ranged from 32 to 79, with an average age of 55 years old; different endovascular techniques and/or hybrid procedures were performed in these patients.

Results

Technical success rate was 100% for the entire group of patients. Type I endoleak occurred in 8 patients immediately after stent-graft placement, which in 2 cases disappeared after a proximal Cuff placement, and the other cases received no special treatment. Follow-up was conducted from 1 month to 72 months, with an average of 36.3 months, and no stent-graft migration or organ ischemia was noted. In the follow-up patients, no type I endoleak occurred but type II endoleak was found in 2 cases, which were cured without treatment; no patient had paraplegia.

Conclusion

Endovascular surgery and hybrid procedures have demonstrable mid- and long-term efficacy in treatment of complex aortic diseases. However, this conclusion still requires multicenter, large-sample studies to further confirm.

Hemodynamic changes lead to alterations in aortic diameters and may challenge further stent graft sizing in acute aortic syndrome

Background

Precise stent graft sizing in Thoracic endovascular aortic repair (TEVAR) is crucial to receive optimal long-term results. Computed tomography (CT), as the current standard in assessing aortic diameters (ADs), is often performed at initial diagnosis. Since several acute aortic diseases are associated with blood loss and/or volume re-distribution, assessed AD might be influenced by impaired hemodynamic conditions. Intravascular ultrasound (IVUS) offers real-time assessment, especially after hemodynamic restoration, and might help for stent graft choice.

Methods

We investigated the correlation between CT and later IVUS measurements in elective (n=83) and emergency patients (n=32) at the level distal to the left subclavian artery (LSA), a frequent proximal landing zone in TEVAR. Patients were grouped depending on their shock index (heart rate/systolic blood pressure): emergency patients with diagnosis of acute aortic syndrome, urgently required treatment after admission and had a shock index >1, otherwise were grouped as elective. Basic hemodynamics were assessed for both groups at admission and at definite IVUS-procedure.

Results

At time of admission the emergency group showed lower blood pressure (99±19.8 vs. 141±24 mmHg; P=0.001) and higher heart rate (98±13 vs. 70±12 bpm; P=0.001) compared to elective patients. By hemodynamic stabilization comparable blood pressure and heart rate were achieved in both groups at time of IVUS. In the emergency group, we found a significantly increase in AD after hemodynamic stabilization, whereas the diameters did not change in the elective group (IVUS_meanvs. CT_mean: 5.1±1.0 vs. 0.4±2.2 mm; P=0.001 and IVUS_minvs. CT_mean: 3.9±1.3 vs. -0.3±2.2 mm; P=0.011).

Conclusions

IVUS for stent graft sizing is a valuable approach during TEVAR, especially in the light of emergency treatment by offering real-time assistance. Impaired hemodynamic conditions might lead to relevant changes in AD and may strongly influence stent graft choice. In these cases, careful stent graft selection might contribute to avoidance of stent graft related complication.

[Endovascular repair of the thoracic aorta]

Degenerative aneurysms of the thoracic aorta are increasing in prevalence. The recognition of the decreased morbidity of this approach compared with open repair was readily apparent, as it avoided left thoracotomy, aortic cross-clamping, and left heart bypass. Repair of isolated descending thoracic aortic aneurysms using stent grafts was introduced in 1995, and in an anatomically suitable subgroup of patients with thoracic aortic aneurysm, repair with endovascular stent graft provides favorable outcomes, with decreased perioperative morbidity and mortality relative to open repair. The cornerstones of successful thoracic endovascular aneurysm repair are appropriate patient selection, thorough preprocedural planning, and cautious procedural execution. Since then, TEVAR is increasingly being used for other aortic pathologies such as complicated type B dissection, traumatic aortic transection, and aneurysmal disease extending into the arch or visceral segment, requiring debranching procedures.

Hemodynamic parameters that may predict false-lumen growth in type-B aortic dissection after endovascular repair: A preliminary study on long-term multiple follow-ups

Thoracic endovascular aortic repair (TEVAR) is commonly applied in type-B aortic dissection. For patients with dissection affects descending aorta and extends downward to involve abdominal aorta and possibly iliac arteries, false lumen (FL) expansion might occur post-TEVAR. Predictions of dissection development may assist in medical decision on re-intervention or surgery. In this study, two patients are selected with similar morphological features at initial presentation but with different long-term FL development post-TEVAR (stable and enlarged FL). Patient-specific models are established for each of the follow-ups. Flow boundaries and computational validations are obtained from Doppler ultrasound velocimetry. By analyzing the hemodynamic parameters, the false-to-true luminal pressure difference (PDiff) and particle relative residence time (RRT) are found related to FL remodeling. It is found that (i) the position of the first FL flow entry is the watershed of negative-and-positive PDiff and, in long-term follow-ups, and the position of largest PDiff is consistent with that of the greatest increase of FL width; (ii) high RRT occurs at the FL proximal tip and similar magnitude of RRT is found in both stable and enlarged cases; (iii) comparing to the RRT at 7days post-TEVAR, an increase of RRT afterwards in short-term is found in the stable case while a slight decrease of this parameter is found in the enlarged case, indicating that the variation of RRT in short-term post-TEVAR might be potential to predict long-term FL remodeling.

Influence of distal entry tears in acute type B aortic dissection after thoracic endovascular aortic repair

OBJECTIVE

This study evaluated the clinical influence of distal entry tears in acute type B aortic dissection (ATBAD) after thoracic endovascular aortic repair (TEVAR).

METHODS

From August 2009 to December 2014, the clinical outcomes of 130 patients who underwent TEVAR for ATBAD were retrospectively analyzed. According to whether distal entry tears existed after TEVAR, patients were divided into group A (n = 25, absence of distal entry tears) and group B (n = 105, presence of distal entry tears). We evaluated clinical outcomes, including mortality and morbidity in early and late follow-up, as well as aortic remolding. Late aortic events were defined as aortic dissection-related events occurring >30 days from the initial TEVAR procedures, which consisted of endoleak, retrograde type A aortic dissection, aortic enlargement, late rupture, repeat dissection, and stent-induced new entry tear.

RESULTS

The study comprised 130 patients (114 men [87.7%] and 16 women [12.3%)] with a mean age of 53.71 years. The 30-day mortality was 3.1%, and early morbidity included type I endoleak, 3.1%, organ failure, 3.8%; stroke, 3.1%; spinal cord ischemia, 0%; and early rupture 1.5%. The overall survival rate by Kaplan-Meier analysis at 1, 3, and 5 years was 93.8%, 89.5%, and 79.2%, respectively. There were no significant differences in early morbidity and 30-day mortality and late survival between group A and group B. However, group A had a significantly lower rate of late aortic events than group B (P = .028 by log-rank test). Meanwhile, group A had better aortic remolding than group B in complete thrombosis of the thoracic aorta at 12 months postoperatively (100% vs 83.5%; P = .029).

CONCLUSIONS

This study demonstrated that TEVAR for ATBAD had low perioperative morbidity and mortality and satisfactory midterm outcome. Distal entry tears increase the occurrence of late aortic events and inhibit aortic remolding but do not have a significantly negative effect on late survival. Repairing all entry tears to restore single-lumen blood flow and enhance false lumen thrombosis might benefit selected patients.

A novel percutaneous double-lumen stent graft technique for treatment of chronic type B aortic dissection under local anesthesia

We present a novel endovascular technique for treatment of chronic dissection with abdominal aortic aneurysm whereby multiple overlapping stent grafts are placed in parallel in the true and false lumens in a 65-year-old woman. The use of multiple stent grafts within each lumen allowed total aneurysm exclusion and prevention of false lumen reperfusion while the parallel placement preserved flow in both lower extremities. Postoperative imaging showed complete exclusion of the aneurysm with patency of all aortic branches and no evidence of endoleak. The success of this novel procedure demonstrates feasibility of parallel stent graft implantation in both true and false lumens.

Short- and Long-term Results of Hybrid Arch and Proximal Descending Thoracic Aortic Repair

Purpose: To evaluate the short- and long-term outcomes of hybrid repair of the arch and proximal descending aorta in a single tertiary center for aortic disease. Methods: A retrospective analysis was performed of 55 patients (median age 67 years; 36 men) who underwent hybrid repair of thoracic aortic pathology with involvement of the arch between January 2005 and May 2015 at a single tertiary center. The pathologies included 40 (73%) with aneurysmal disease, 10 (18%) acute type B aortic dissections, 2 with acute aortic syndrome, an acute type A dissection, and left and aberrant right subclavian artery aneurysms. Seven (13%) procedures were performed as an emergency. Demographics and procedure characteristics were collected for analysis of survival and reinterventions. Results: Complete aortic debranching was performed in 14 (25%) to facilitate endograft placement in zone 0; debranching was partial in 20 (36%) patients for zone 1 deployments and 21 (38%) for zone 2. Primary technical success was achieved in 51 (93%) cases. One patient died in-hospital from aneurysm rupture following aortic debranching prior to stent-graft repair. In another, the stent-graft procedure proved infeasible and was abandoned. The other 2 technical failures were due to type Ia endoleaks. Five (9%) patients died in-hospital (4 of 48 elective and 1 of 7 emergency cases); 2 of these patients died within 30 days (4%). Eight (14%) patients had a stroke, 6 of 48 elective and 2 of the 7 emergency patients. Spinal cord ischemia was reported in 3 (6%) patients. Mean follow-up was 74.6 months. Overall cumulative survival was 70% at 1 year, 68% at 2 years, and 57% at 5 years. Reintervention to the proximal landing zone for type Ia endoleak was required in 6% of cases. The overall rate of aortic reintervention was 18% at 1 year, 21% at 2 years, and 36% at 5 years. Overall extra-anatomic graft patency was 99%. Conclusion: Hybrid repair of the aortic arch and proximal descending thoracic aorta is technically feasible, with acceptable short-term mortality. There is a low rate of proximal landing zone reintervention when hybrid techniques are used to create an adequate proximal landing zone. Extra-anatomic bypass grafts have good long-term patency. Ongoing disease progression means that further distal aortic interventions are often necessary in patients with extensive disease.

Outcomes of Patients With Acute Type B (DeBakey III) Aortic Dissection: A 13-Year, Single-Center Experience

Background—

Aortic dissection remains the most common aortic catastrophe. In the endovascular era, the management of acute type B aortic dissection (ATBAD) is undergoing dramatic changes. The aim of this study is to evaluate the long-term outcomes of patients with ATBAD who were treated at our center over a 13-year period.

Methods and Results—

We reviewed patients with ATBAD between 2001 and 2014, analyzing variables based on status (complicated [c] versus uncomplicated [u]) and treatment modalities. We defined cATBAD as rupture, expansion of diameter on imaging during the admission, persistent pain, or clinical malperfusion leading to a deficit in cerebral, spinal, visceral, renal, or peripheral vascular territories at presentation or during initial hospitalization. Postoperative outcomes were defined as deficits not present before the intervention. Outcomes were compared between the groups by use of Kaplan-Meier and descriptive statistics. We treated 442 patients with ATBAD. Of those 442, 60.6% had uATBAD and were treated medically, and 39.4% had cATBAD, of whom 39.0% were treated medically to 30.0% with open repair, 21.3% with thoracic endovascular aortic repair, and 9.7% with other open peripheral procedures. Intervention-free survival at 1 and 5 years was 84.8% and 62.7% for uATBAD, 61.8% and 44.0% for cATBAD-medical, 69.2% and 47.2% for cATBAD-open, and 68.0% and 42.5% for cATBAD–thoracic endovascular aortic repair, respectively (P=0.001). Overall survival was significantly related primarily to complicated presentation.

Conclusions—

In our experience, early and late outcomes of ATBAD were dependent on the presence of complications, with cATBAD faring worse. Although uATBAD was associated with favorable early survival, late complications still occurred, mandating radiographic surveillance and open or endovascular interventions. Prospective trials are required to better determine the optimal therapy for uATBAD.

Relationship between acute kidney injury before thoracic endovascular aneurysm repair and in-hospital outcomes in patients with type B acute aortic dissection

Objective

Acute kidney injury (AKI) frequently occurs after catheter-based interventional procedures and increases mortality. However, the implications of AKI before thoracic endovascular aneurysm repair (TEVAR) of type B acute aortic dissection (AAD) remain unclear. This study evaluated the incidence, predictors, and in-hospital outcomes of AKI before TEVAR in patients with type B AAD.

Methods

Between 2009 and 2013, 76 patients were retrospectively evaluated who received TEVAR for type B AAD within 36 h from symptom onset. The patients were classified into no-AKI vs. AKI groups, and the severity of AKI was further staged according to kidney disease: improving global outcomes criteria before TEVAR.

Results

The incidence of preoperative AKI was 36.8%. In-hospital complications was significantly higher in patients with preoperative AKI compared with no-AKI (50.0% vs. 4.2%, respectively; P < 0.001), including acute renal failure (21.4% vs. 0, respectively; P < 0.001), and they increased with severity of AKI (P < 0.001). The maximum levels of body temperature and white blood cell count were significantly related to maximum serum creatinine level before TEVAR. Multivariate analysis showed that systolic blood pressure on admission (OR: 1.023; 95% CI: 1.003–1.044; P = 0.0238) and bilateral renal artery involvement (OR: 19.076; 95% CI: 1.914–190.164; P = 0.0120) were strong predictors of preoperative AKI.

Conclusions

Preoperative AKI frequently occurred in patients with type B AAD, and correlated with higher in-hospital complications and enhanced inflammatory reaction. Systolic blood pressure on admission and bilateral renal artery involvement were major risk factors for AKI before TEVAR.

Management of acute aortic dissection

A new appraisal of the management of acute aortic dissection is timely because of recent developments in diagnostic strategies (including biomarkers and imaging), endograft design, and surgical treatment, which have led to a better understanding of the epidemiology, risk factors, and molecular nature of aortic dissection. Although open surgery is the main treatment for proximal aortic repair, use of endovascular management is now established for complicated distal dissection and distal arch repair, and has recently been discussed as a pre-emptive measure to avoid late complications by inducing aortic remodelling.

Early and late management of type B aortic dissection

The management of type B aortic dissection is undergoing profound changes with timely TEVAR accepted as first-line strategy in the setting of complicated dissection; with recent technological advances and in experienced hands this intervention is considered safe and life-saving. With the ability to remodel the dissected aorta as a result of scaffolding even pre-emptive endovascular treatment is being considered and supported by long-term stability and often prevention of aneurysmal expansion. This insight and a growing number of silent risk conditions (resistant hypertension, partial false lumen thrombosis) may lower the threshold for TEVAR in asymptomatic patients in the subacute phase. In the chronic phase of a type B dissection patients are usually free of symptoms, however, with the expanding false lumen at risk of rupture. Advanced TEVAR options (including branches and fenestrations) are likely to be used more often than open surgical replacement of such aneurysmatic segment of the dissected aorta in that chronic phase. All dissection patients should be offered lifelong surveillance.

Survival after endovascular therapy in patients with type B aortic dissection: a report from the International Registry of Acute Aortic Dissection (IRAD)

OBJECTIVES

This study sought to evaluate long-term survival in type B aortic dissection patients treated with thoracic endovascular aortic repair (TEVAR) therapy.

BACKGROUND

Historical data have supported medical therapy in type B acute aortic dissection (TBAAD) patients. Recent advances in TEVAR appear to improve in-hospital mortality.

METHODS

We examined 1,129 consecutive patients with TBAAD enrolled in IRAD (International Registry of Acute Aortic Dissection) between 1995 and 2012 who received medical (n = 853, 75.6%) or TEVAR (n = 276, 24.4%) therapy.

RESULTS

Clinical history was similar between groups. TEVAR patients were more likely to present with a pulse deficit (28.3% vs. 13.4%, p < 0.001) and lower extremity ischemia (16.8% vs. 3.6%, p < 0.001), and to characterize their pain as the "worst pain ever" (27.5% vs. 15.7%, p < 0.001). TEVAR patients were also most likely to present with complicated acute aortic dissection, defined as shock, periaortic hematoma, signs of malperfusion, stroke, spinal cord ischemia, mesenteric ischemia, and/or renal failure (61.7% vs. 37.2%). In-hospital mortality was similar in patients managed with endovascular repair (10.9% vs. 8.7%, p = 0.273) compared with medically managed patients. One-year mortality was also similar in both groups (8.1% endovascular vs. 9.8% medical, p = 0.604). Among adverse events during follow-up, aortic growth/new aneurysm was most common, occurring in 73.3% of patients with medical therapy and in 62.7% of patients after TEVAR, based on 5-year Kaplan-Meier estimates. Kaplan-Meier survival estimates showed that patients undergoing TEVAR had a lower death rate (15.5% vs. 29.0%, p = 0.018) at 5 years.

CONCLUSIONS

Results from IRAD show that TEVAR is associated with lower mortality over a 5-year period than medical therapy for TBAAD. Further randomized trials with long-term follow-up are needed.

Reintervention after thoracic endovascular aortic repair of complicated aortic dissection

OBJECTIVE

This study assessed predictive factors for reintervention after thoracic endovascular aortic repair (TEVAR) for complicated aortic dissection (C-AD).

METHODS

An institutional review of consecutive TEVAR for C-AD was performed.

RESULTS

Between 2000 and 2011, 41 patients underwent TEVAR for a C-AD involving the descending thoracic aorta. Primary indications included aneurysm >55 mm in 24, rapid aneurysmal enlargement or impending rupture in 6, saccular aneurysm >20 mm in 1, malperfusion in 1, intractable chest pain in 3, and rupture in 6. Technical success was achieved in 100%. The 30-day mortality rate was 5% (n = 2). Fourteen secondary procedures were performed in 13 patients (32%) for indications of device migration in 2, proximal type I endoleak in 5, distal type I endoleak in 2, type II endoleak in 1, aneurysmal evolution of the descending thoracic aorta in 2, aneurysmal expansion of the dissected abdominal aorta in 1, and retrograde dissection in 1. Multivariate analysis demonstrated that oversizing ≥20% (odds ratio [OR], 16; P = .011), bare-spring stent in the proximal landing zone of the stent graft (OR, 12; P = .032), and anticoagulant therapy (OR, 78; P = .03) were significant factors for reintervention. On univariate analysis, large aneurysm was a risk factor for reintervention (P = .002), whereas complete false lumen thrombosis at the stent graft level was protective (P < .05).

CONCLUSIONS

This study confirms the feasibility of TEVAR for C-AD, although the rate of reintervention is high. Excessive oversizing, a bare-spring stent graft in the proximal landing zone, large aortic dilatation, and anticoagulant therapy were factors associated with reintervention. Complete false lumen thrombosis at the stent graft level was protective.

Current evidence for thoracic aorta type B dissection management

Aortic dissection is a devastating cardiovascular condition and represents the most common aortic emergency. Outcome is determined by the type and extent of dissection and the presence of associated complications requiring early diagnosis and treatment. Aortic dissection is defined as acute within 14 days from onset and chronic after that time period. The natural course of type B dissection is determined by 2 elements, early and chronic complications. An uncomplicated acute type B dissection is less frequently lethal but it is not totally benign. Some peculiar issues must be taken into account, such as the high probability of complications development in a dissected aorta and the poor long-term prognosis on medical treatment alone. Then, it would be helpful to identify which patients with uncomplicated type B dissection will have a poorest aortic prognosis over time in order to apply an early intervention.

Endovascular repair of type B aortic dissection: long-term results of the randomized investigation of stent grafts in aortic dissection trial

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) represents a therapeutic concept for type B aortic dissection. Long-term outcomes and morphology after TEVAR for uncomplicated dissection are unknown.

METHODS AND RESULTS

A total of 140 patients with stable type B aortic dissection previously randomized to optimal medical treatment and TEVAR (n=72) versus optimal medical treatment alone (n=68) were analyzed retrospectively for aorta-specific, all-cause outcomes, and disease progression using landmark statistical analysis of years 2 to 5 after index procedure. Cox regression was used to compare outcomes between groups; all analyses are based on intention to treat. The risk of all-cause mortality (11.1% versus 19.3%; P=0.13), aorta-specific mortality (6.9% versus 19.3%; P=0.04), and progression (27.0% versus 46.1%; P=0.04) after 5 years was lower with TEVAR than with optimal medical treatment alone. Landmark analysis suggested a benefit of TEVAR for all end points between 2 and 5 years; for example, for all-cause mortality (0% versus 16.9%; P=0.0003), aorta-specific mortality (0% versus 16.9%; P=0.0005), and for progression (4.1% versus 28.1%; P=0.004); Landmarking at 1 year and 1 month revealed consistent findings. Both improved survival and less progression of disease at 5 years after elective TEVAR were associated with stent graft induced false lumen thrombosis in 90.6% of cases (P<0.0001).

CONCLUSIONS

In this study of survivors of type B aortic dissection, TEVAR in addition to optimal medical treatment is associated with improved 5-year aorta-specific survival and delayed disease progression. In stable type B dissection with suitable anatomy, preemptive TEVAR should be considered to improve late outcome.

CLINICAL TRIAL REGISTRATION URL

http://www.clinicaltrials.gov. Unique identifier: NCT01415804.

Hybrid aortic arch repair for complicated type B aortic dissection

OBJECTIVE

This study analyzed the outcome of a combined endovascular and debranching procedure for hybrid aortic arch repair (HAR) in patients with complicated type B aortic dissection.

METHODS

Between February 2006 and August 2012, HAR was performed in 75 consecutive patients, with retrospective analysis of a subgroup of 45 patients who underwent HAR with complicated acute (n = 10), subacute (n = 7), or chronic (n = 28) type B dissection as the underlying disease. Descriptive statistics were computed for continuous and categoric variables. The interval to death or last follow-up was estimated using the Kaplan-Meier method.

RESULTS

The patients were a mean age of 59.9 ± 10.7 years (median, 59.2; range, 35-78 years). Complete supra-aortic debranching was performed in six (13%) in zone 0 (procedure time, 200 minutes; range, 185-365 minutes) and partial debranching in 39 (87%), comprising 16 (36%) in zone 1 (procedure time, 120 minutes; range, 75-250 minutes) and 23 (51%) in zone 2 (procedure time, 91 minutes; range, 70-210 minutes). Technical success was achieved in 86.7% (39 of 45). Thirty-day mortality was 4.4% (two of 45), with an in-hospital mortality of 11.1% (five of 45) as a result of three additional deaths after days 33, 35, and 111. Comparing HAR for type B dissection after complete debranching in six and partial debranching in 39, the overall in-hospital mortality was 67% (four of six) and 2.6% (one of 39), respectively. After a median follow-up of 20.8 months (range, 0.3-70 months), the overall mortality was 13.3% (six of 45), with Kaplan-Meier survival estimate of 85% at 1 year. Stroke rate was 8.8% (four of 45). Paraplegia developed in one patient (2.2%), with complete recovery after spinal drainage. Cardiac complications occurred in three patients (6.7%), pulmonary complications in 10 (22.2%), and renal insufficiency requiring dialysis developed in five (11%). Retrograde dissection occurred in one patient (2.2%) 14 days after complete debranching and zone 0 thoracic endovascular aortic repair, with fatal outcome. No bypass dysfunction was seen during follow-up. The overall early and late endoleak rates were 27% (12 of 44) and 43% (13 of 30), respectively. Eight patients (18%) required reintervention, with freedom of reintervention in 91% at 1 year and 81% at 2 years.

CONCLUSIONS

HAR in zone 1 and 2 appears a viable alternative to conventional aortic arch surgery in patients with complicated type B dissection. Stroke and endoleaks remain complications that need to be addressed. Treatment of type B aortic dissection with complete supra-aortic debranching and thoracic endovascular aortic repair in zone 0, however, is associated with high mortality, which might be reduced by improved technology using branched stent grafts.

[Stent graft of the thoracic aorta]

Considering the demographic changes in our society and the proliferation of imaging-based improved diagnostics, both acute and chronic aortic diseases attract increasing attention and require dedicated care. Cardiac as well as vascular surgery used to represent the gold standards for therapeutic management of pathologies of the ascending aorta and the arch; however, the technological evolution of endoluminal strategies has had a serious impact on the treatment of the descending aorta, the aortic arch in combination with vascular debranching or bypass, and in selected cases even on managing pathologies of the ascending aorta. Although several case series and meta-analyses of published observations hint towards superiority of endografting in comparison to open surgical repair, the affected usually multimorbid patients with highly complex aortic disease should be subjected to an individual evaluation by a team of cardiologists, cardiac and vascular surgeons as well as imaging specialists; a dedicated individualized treatment concept in highly experienced centers of excellence is likely to provide the best results for such challenging patients.

Progress in management of malperfusion syndrome from type B dissections

OBJECTIVE

Malperfusion syndrome is a known predictor of poor outcomes in acute type B dissection. We describe our experience with revascularization in the acute setting.

METHODS

Patients undergoing intervention for ischemia complicated acute type B dissection between November 1999 and March 2011 were reviewed. Details of presenting condition, surgical intervention, and postoperative course were collected. Descriptive and inferential statistical analyses included survival and freedom from reintervention using Cox proportional hazards models.

RESULTS

A total of 61 patients were identified with malperfusion in at least one territory, including spinal cord 7/61 (12%), mesenteric 37/61 (61%), renal 45/61 (73%), and lower extremity 38/61 (62%). Thoracic stent grafts were placed in all patients, and 41% of patients required adjunctive branch vessel stenting. After intervention, resolution of the ischemia was reported in 57/61 (93%) of patients. The 30-day/in-hospital mortality was 21.3%. The 6-month, 1-year, and 5-year survival was 75% (95% CI, 65%-87%), 71% (95% CI, 61%-84%), and 56% (95% CI, 43%-74%), respectively. The 6-month, 1-year, and 5-year freedom from reintervention was 84% (95% CI, 75%-95%), 76% (95% CI, 65%-90%), and 42% (95% CI, 24%-76%), respectively. Territory of ischemia was not independently associated with mortality, but placement of a stent graft proximal to the subclavian artery was associated with poor outcome hazard ratio 2.91 (95% CI, 1.09-8.11; P = .034).

CONCLUSIONS

Malperfusion in any territory at the time of presentation in patients with type B dissections can be treated with endovascular intervention with acceptable outcomes. Opposed to branch vessel intervention alone, increased aortic intervention with regard to proximal coverage may signify more serious disease is associated with worse outcome.