Early outcomes of the conformable stent graft for acute complicated and uncomplicated type B aortic dissection

The efficacy and safety of Gore conformable thoracic stent graft and Valiant Captivia thoracic stent graft for acute type B aortic dissection

BACKGROUND

To evaluate the safety and efficacy of the conformable thoracic aortic endograft (Conformable TAG Thoracic Endoprosthesis [CTAG]; W. L. Gore & Associates, Flagstaff, Ariz) and Valiant Captivia thoracic stent graft (Medtronic Inc., Santa Rosa, CA) for acute type B aortic dissection (TBAD).

METHODS

The early and mid-term outcomes were analyzed for 413 patients undergoing TEVAR using conformable TAG thoracic endoprosthesis and Valiant Captivia thoracic stent graft for acute TBAD. 100 propensity-matched pairs of patients were generated, including 100 patients in the CTAG group and 200 patients in the Valiant Captivia group.

RESULTS

Operative mortality were 2.33% (3 of 129) in the CTAG group and 1.76% (5 of 284) in the Valiant Captivia group. The median follow-up was 41.67 (26.00-60.67) months. No significant difference in mortality (9 [7.00%] vs. 36 [12.68%], P = 0.95) or re-intervention rate (3 [2.33%] vs. 20 [7.04%], P = 0.29) was observed between two groups. CTAG group have a lower incidence rate of distal stent graft-induced new entry tear than Valiant Captivia group (2.33% vs. 9.86%, P = 0.045). Lower incidence of type Ia endoleak was identified in the CTAG group (2.22%) than the Valiant Captivia group (14.41%) in patients with type III arch (P = 0.039).

CONCLUSIONS

Both Valiant Captivia thoracic stent graft and CTAG thoracic endoprosthesis can be safely performed for acute TBAD with low operative mortality, favorable mid-term survival and freedom from reintervention. CTAG thoracic endoprosthesis had fewer dSINE even with larger oversizing and potentially suitable for type III arch with fewer type Ia endoleaks.

Research and clinical translation of trilayer stent-graft of expanded polytetrafluoroethylene for interventional treatment of aortic dissection

The aortic dissection (AD) is a life-threatening disease. The transcatheter endovascular aortic repair (EVAR) affords a minimally invasive technique to save lives of these critical patients, and an appropriate stent-graft gets to be the key medical device during an EVAR procedure. Herein, we report a trilayer stent-graft and corresponding delivery system used for the treatment of the AD disease. The stent-graft is made of nitinol stents with an asymmetric Z-wave design and two expanded polytetrafluoroethylene (ePTFE) membranes. Each of inner and outer surfaces of the stent-graft was covered by an ePTFE membrane, and the two membranes were then sintered together. The biological studies of the sintered ePTFE membranes indicated that the stent-graft had excellent cytocompatibility and hemocompatibility in vitro. Both the stent-graft and the delivery system exhibited satisfactory mechanical properties and operability. The safety and efficacy of this stent-graft and the corresponding delivery system were demonstrated in vivo. In 9 canine experiments, the blood vessels of the animals implanted with the stent-grafts were of good patency, and there were no thrombus and obvious stenosis by angiography after implantation for 6 months. Furthermore, all of the 9 clinical cases experienced successful implantation using the stent-graft and its post-release delivery system, and the one-year follow-ups indicated the preliminary safety and efficacy of the trilayer stent-graft with an asymmetric Z-wave design for interventional treatment.

The misnomer of uncomplicated type B aortic dissection

BACKGROUND

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

AIMS

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

METHODS

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

RESULTS

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

CONCLUSION

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

OUP accepted manuscript

The proper surgical strategy for retrograde type A aortic dissection (RTAD) is still controversial, and some studies have reported the efficacy of frozen elephant trunk and thoracic endovascular aortic repair (TEVAR). A 68-year-old man was diagnosed with acute type A aortic dissection using enhanced computed tomography. The false lumen at the arch and ascending aorta was thrombosed, and the primary entry was placed in the descending aorta. In addition, there were malperfusions of the right renal artery and both iliac arteries. We performed TEVAR using the right femoral artery combined with the petticoat technique. At 11 days postoperatively, we observed rapid aortic remodeling at the arch and ascending aorta. The patient was discharged uneventfully after 14 days. We believe that TEVAR for RTAD is effective in appropriate patients. However, the accumulation of the number of cases and accurate strategies for patient selection are in demand.

Aortic-related Readmission after Thoracic Endovascular Aortic Repair for Type B Aortic Dissection Patients: A Single-center Retrospective Study

OBJECTIVES

This study aimed to investigate the characteristics of and risk factors for aortic-related readmission after thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD).

METHODS

Data from TBAD patients who underwent TEVAR from 2009-2018 at a Chinese tertiary center were retrospectively collected and analyzed. Enrolled patients were categorized into two groups according to whether aortic-related readmission occurred during follow-up, which was defined as hospitalization at least once after the initial procedure due to events that were related to or caused by aortic dissection or the initial procedure.

RESULTS

A total of 1 288 TBAD patients were enrolled, and 99 patients experienced aortic-related readmissions (7.7%), among whom chronic patients had the highest readmission rate (9.8%). The yearly proportion of readmission during the first year after initial procedure revealed a decreasing trend with a -9.7% annual percentage change. Seventy-one patients underwent reintervention (71.7%). Distal aneurysmal degeneration (43.7%) and distal stent graft-induced new entries (32.4%) were two major causes for reintervention. Fourteen patients in the reintervention subgroup underwent a second reintervention (19.7%). In-hospital mortality was 1.0% during the readmission and 14.3% during the second readmission. The overall survival was comparable between two groups (p=.93).

CONCLUSIONS

This study highlighted the importance of surveillance after initial procedure for TBAD patients with potential risk factors for aortic-related readmission, and the predisposition of patients with reintervention to multiple readmissions deserves attention.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Is TEVAR really needed for uncomplicated type B aortic dissection?

Thoracic endovascular aortic repair (TEVAR) has quickly become the mainstay of treatment for acute aortic dissection, in particular cases of acute complicated Stanford Type B dissection (co-TBAD). Necessarily, TEVAR carries with it the risk of postoperative complications, including stroke and renal failure. As a result, the management of patients with uncomplicated type B aortic dissection (un-TBAD), which is generally accepted as being less severe, is safely managed via optimal medical therapy (OMT) alone. However, despite OMT, patients with un-TBAD are at substantial risk of severe disease progression requiring delayed intervention. The cost-benefit ratio associated with TEVAR for un-TBAD is therefore of key interest. Howard and colleagues produced a fascinating systematic review and meta-analysis investigating the clinical outcomes of TEVAR for complicated and uncomplicated TBAD. Their data suggest that there is no significant difference in in-hospital mortality or 5-year survival between TEVAR for un-TBAD and co-TBAD, although the 30-day mortality rate appeared to be higher in the co-TBAD cohort. Patients with co-TBAD appeared to also be at a higher risk of postoperative stroke and TEVAR endoleak, while un-TBAD patients were at a higher risk of postoperative renal failure. Further prospective research into these relationships is recommended to fully elucidate the comparative efficacies of TEVAR for un-TBAD and co-TBAD.

Ten-Year Clinical Characteristics and Early Outcomes of Type B Aortic Dissection Patients With Thoracic Endovascular Aortic Repair

OBJECTIVE/BACKGROUND

This study examined the 10-year hospitalization characteristics, economic patterns and early clinical outcomes of type B aortic dissection (TBAD) patients that underwent thoracic endovascular aortic repair (TEVAR) in one high-volume hospital in China.

METHODS

We performed a population-based retrospective analysis based on electronic medical record system data provided by Zhongshan Hospital Fudan University from 2009 to 2018.

RESULTS

We identified 1,367 cases of TBAD patients with TEVAR over the past decade. The total incidence of in-hospital complications was 7.6% (104 of 1,367), among which acute kidney injury (AKI) had the highest incidence (3.1%, 42 of 1,367). Aortic-related reintervention was performed in 7 patients (0.5%). The overall aortic-related in-hospital mortality rate was 2.7% (37 of 1,367) and had no significant time-varying trend (P = 0.2). Among these, 27% of in-hospital deaths were caused by retrograde type A dissection (RTAD). Chronic TBAD had a higher risk of in-hospital death versus acute TBAD, with a risk ratio of 2.69 (95% confidence interval [CI]: 1.19-6.09). Patients with hypertension (risk ratio 4.63, 95% CI: 1.38, 15.54) also had a higher in-hospital death risk. These 2 factors were also the predictive factors for the composite endpoint of in-hospital adverse events (risk ratio 2.17, 95% CI: 1.43, 3.29 and risk ratio 4.83, 95% CI: 1.90, 12.28, respectively), in addition to Marfan syndrome (risk ratio 4.05, 95% CI: 1.61, 10.19). The average length of hospitalization significantly declined during the past decade (annual percentage change -6.3%, 95% CI -8.2 to -4.3), and the stent-grafts (SGs) cost was the main expenditure of the total hospitalization costs.

CONCLUSION

Our study showed a favorable early outcome of TEVAR over the past decade. Greater attention should be paid to certain risk factors in order to reduce the in-hospital adverse events. SG expenditure is still the primary economic burden on Chinese TBAD patients.

Outcomes of emergency in situ laser fenestration-assisted thoracic endovascular aortic repair in patients with acute Stanford type A aortic dissection unfit for open surgery

OBJECTIVE

This study investigated the outcomes of emergency in situ laser fenestration (ISLF)-assisted thoracic endovascular aortic repair (TEVAR) for patients with acute Stanford type A aortic dissection unfit for open surgery.

METHODS

Twenty patients with acute Stanford type A aortic dissection who were found to be unfit for open surgery, underwent emergency ISLF-assisted TEVAR in our center between March 2016 and December 2018. Anatomic criteria for endovascular repair: coronary artery and aortic valve was not involved, proximal landing zone diameter of 45 mm or less, and proximal landing zone length of 20 mm or greater. Their clinical outcomes were reviewed retrospectively.

RESULTS

Twenty patients achieved a procedural success of 100.0%. The 30-day mortality was 10%; two patients died, one of severe pneumonia and the other from cerebral hemorrhage after the operation. Rate of stroke at 30 days was 5%. The average follow-up time was 16 months (range, 3-26 months). One death owing to heart failure occurred at 23 months postoperatively. Kaplan-Meier curve analysis revealed that the 24-month survival rate was 77.1%. Two patients had type Ia endoleaks and one had a type II endoleak. There was no stent graft migration or fenestration-related endoleak and all patients had a thrombosed false lumen in the covered section of the stent grafts. No reintervention, myocardial infarction, transient ischemic attacks, cerebral infarction, or other complications occurred during the follow-up period.

CONCLUSIONS

Emergency ISLF-assisted TEVAR is a safe and effective alternative method for treating acute Stanford type A aortic dissection unfit for open surgery.

Impact of the Bird-Beak Configuration on Postoperative Outcome After Thoracic Endovascular Aortic Repair: A Meta-analysis

Purpose: To investigate the association between the bird-beak configuration (BBC), a wedge-shaped gap between the undersurface of a thoracic endograft and the lesser curvature of the arch after thoracic endovascular aortic repair (TEVAR), and postoperative outcome after TEVAR. Methods: The study was performed according to the PRISMA guidelines. The PubMed, EMBASE, and Cochrane databases were searched to identify all case series reporting BBC after TEVAR between 2006 and April 2018. Data analysis was performed considering the difference in the risk of complications for presence vs absence of BBC. After screening 1633 articles, 21 studies were identified that matched the selection criteria; 12 of these reported detailed information to investigate the postoperative outcome using proportion meta-analysis with a random effects model. The pooled risk difference is reported with the 95% confidence interval (CI). Heterogeneity of the included studies was assessed with the I2 statistic (low 25%, medium 50%, high 75%). Results: Complications occurred within a range of 0 to 72 months in 14.7% (95% CI 7.4% to 27.3%) of patients with BBC and in 6.3% (95% CI 2.5% to 15.4%) of patients without BBC. A cumulative incidence could not be assessed. The summary risk difference was 11.1% (95% CI −0.1% to 22.3%, p=0.052). There was significant heterogeneity ( I2=85.6%). The Egger test did not show evidence of publication bias (p=0.975). When specifically considering type Ia endoleak and endograft migration, the risk difference between BBC and non-BBC patients was 8.2% (95% CI 0.3% to 16.1%, p=0.042; I2=69.0%). The specific risk difference for endograft collapse/infolding and thrombosis was 3.7% (95% CI −3.5% to 11.1%, p=0.308; I2=10.2%). Conclusion: At present the literature does not provide statistical evidence to establish an overall prognostic value of the BBC. Nevertheless, the BBC appears to be associated with a high risk of type Ia endoleak and endograft migration, which warrants specific and long-term surveillance. Clinically relevant values for BBC grading should be established to perhaps define indications for preemptive treatment based on the presence of BBC only.

Proposed classification of endoleaks after endovascular treatment of Stanford type-B aortic dissections

Objectives

Despite two decades of experience, no dedicated classification system exists to document and prognosticate patterns of endoleak encountered after endovascular therapy of type-B aortic dissection. This nomenclature gap has led to inconsistent management and underreporting of significant findings associated with adverse outcomes after endovascular treatment of type-B aortic dissection. Our goal was to propose a reproducible and prognostically relevant classification.

Methods

A multidisciplinary team of seven experienced open and endovascular aortic surgeons was assembled to provide consensus opinion. Extensive literature review was conducted. Deficiencies in the current classification approach of the various patterns of persistent filling of false lumen after endovascular therapy were identified.

Results

Our focus was to categorize high-risk and low-risk subgroups within endoleaks after endovascular treatment of type-B aortic dissection. In this classification, type-Ia endoleak refers to persistent filling of the false lumen in an antegrade manner. Causes include failure to cover the primary entry tear and sizing or technical related proximal seal failure. False lumen filling via distal entry tears is classified as type Ib endoleak, which is further sub-classified into b1 (major branch-related tears), and b2 (multiple small branches related tears). Retrograde ascending aortic dissection and stent graft-induced new entry were classified as type-I endoleaks (type-Ir and type-Is, respectively). Another focus was reclassification type-II endoleaks, with type-IIa endoleak referring to conventional retroleak from one or more posterior branches and type-IIx referring to retroleak from major branches (visceral or left subclavian arteries).

Conclusions

The majority of endoleaks after endovascular treatment of type-B aortic dissection are related to persistent or new filling of the false lumen. We propose a new false lumen-based classification schema for endoleaks occurring after endovascular therapy of type-B aortic dissection.

Equations Estimating the Predissected Diameter of the Ascending Aorta for Acute Type A Aortic Dissection

BACKGROUND

A successful endovascular treatment for acute type A dissection has been recently reported. However, there has been no consensus regarding the appropriate stent graft size based on the estimated predissected aortic diameter for this pathology.

METHODS

We developed new equations for estimating the predissected ascending aorta and aortic arch by investigating computed tomography images that had been scanned less than 3 years before dissection. From 684 patients with type A AAD, 28 were matched for the study. We measured the predissected whole circumference length (pre-wCL), postdissected whole circumference length (post-wCL), postdissected true lumen circumference length (post-tCL), postdissected major diameter (post-Dma), and postdissected minor diameter (post-Dmi) of the acutely dissected aorta. This was followed by the calculation of (post-tCL + post-wCL)/2 and (post-Dma + post-Dmi)/2. Six equations (linear function) and modified equations were derived from each of the abovementioned parameters.

RESULTS

Four equations (post-wCL, post-Dma, [post-tCL + post-wCL]/2, and [post-Dma + post-Dmi]/2) had nearly the same bias and accuracy (<9.42 mm). For clinical use, we also developed one modified equation using the post-wCL (y = 0.9x) among four parameters because of its simplicity and decreased the possibility of measurement error. The biases of circumference length and accuracy were 5.5 ± 4.9 mm and 84.6%, respectively, and they improved to 4.4 ± 3.3 mm and 93.4% in cases with a ratio of post-tCL/post-wCL of 0.66 or more.

CONCLUSIONS

Our newly developed equation can be used to calculate the predissected ascending aortic diameter and aortic arch diameter in cases of acute type A dissection.

Equations for Estimating the Predissected Diameter of the Descending Aorta From Computed Tomographic Images at the Onset of Aortic Dissection

BACKGROUND

Estimation of the predissected descending aortic diameter is important for deciding on the size of a stent graft in cases of acute aortic dissection. However, no equations for estimating this diameter have been previously reported.

METHODS AND RESULTS

We developed and validated new equations by investigating computed tomography images that were scanned within 3 years before dissection and those that were scanned immediately after the onset of dissection. Among 1127 patients with acute aortic dissection (425 type A and 702 type B), 36 were matched for the study from October 2005 to March 2017 at 4 centers. New equations were developed in 17 patients and validated in 19 patients. We measured the predissected whole circumference length (CL) and postdissected whole CL, true lumen CL, the major diameter, and the minor diameter of the acutely dissected aorta, followed by calculation of (post-trueCL+post-wholeCL)/2 and (post-major diameter+post-minor diameter)/2. Six equations (linear function) and modified equations were derived from each of the above-mentioned parameters. In the derivation sets, equations that used the parameter of (post-trueCL+post-wholeCL)/2 were strongly correlated with pre-wholeCL (Y=0.9433x+5.0147; R²=0.9001) and showed significantly less bias compared with the other 5 equations (P<0.0001). In validation sets using this equation, the mean bias of the circumference length and diameter was 2.7±2.8 and 0.85±0.89 mm, respectively. A total of 99.2% of the calculated values were within 3 mm in diameter or less.

CONCLUSIONS

Our newly developed equations can be used to calculate the predissected aortic diameter in cases of acute aortic dissection and might help to decide the size of the stent graft.

Correlation between Sex and Prognosis of Acute Aortic Dissection in the Chinese Population

BACKGROUND

The prevalence, presentation, management, and prognosis of coronary heart disease differ according to sex. Greater understanding on the differences between men and women with acute aortic dissection (AAD) is needed. We aimed to investigate whether sex disparities are found in patients with AAD, and to study sex differences in complications, mortality in-hospital, and long-term.

METHODS

We included 884 patients enrolled in our institute between June 2002 and May 2016. Considering psychosocial factors, treatments, and the outcomes in men versus those in women with AAD, we explored the association of sex with psychosocial characteristics and mortality risk. For categorical variables, significant differences between groups were assessed with the Chi-square test or Fisher's exact test, and continuous parameters were assessed with Student's t-test. Univariate and stratified survival statistics were computed using Kaplan-Meier analysis.

RESULTS

A total of 884 patients (76.1% male, mean age 51.4 ± 11.8 years) were included in this study. There were fewer current smokers in female compared with male (17.5% vs. 67.2%, χ2 = 160.06, P < 0.05). The percentage of men who reported regular alcohol consumption was significantly higher than that in women (40.6% vs. 3.8%, χ2 = 100.18, P < 0.05). About 6.2% (55 of 884) of patients with AAD died before vascular or endovascular surgery was performed, 34.4% (304 of 884) of patients underwent surgical procedures, and 52.7% (466 of 884) and 12.8% (113 of 884) of patients received endovascular treatment and medication. Postoperative mortality similar (6.0% vs. 5.6%, respectively, χ2 = 0.03, P = 0.91) between men and women. Follow-up was completed in 653 of 829 patients (78.8%). Adjustment for age, history of coronary disease, hypertension, smoking and drinking, Type A and use of beta-blocker, angiotensin II receptor blockers, angiotensin converting enzyme (ACE) inhibitor, calcium-channel blockers and statins by multivariate logistic regression analysis suggested that age (odds ratios [OR s], 1.04; 95% confidence interval [CI], 1.01-1.07; P < 0.05), using of calcium-channel blockers (OR, 0.37; 95% CI, 0.18-0.74; P < 0.05), at discharge were independent predictors of late mortality, ACE inhibitors (OR, 1.91; 95% CI, 1.03-3.54; P = 0.04) was independent risk factor of late mortality.

CONCLUSIONS

In Chinese with AAD, sex is not independently associated with long-term clinical outcomes. Age, the intake of calcium-channel blockers at discharge might help to improve long-term outcomes.