Aortic remodeling after endovascular treatment of complicated type B aortic dissection with the use of a composite device design

Successful Factors for Improving Aortic Remodeling with Thoracic Endovascular Repair and Bare Stent Extension

OBJECTIVE

Proximal ExTension to Induce COmplete ATtachment (PETTICOAT), which utilizes downstream bare metal stents for structural support, demonstrates potential, yet its adoption is limited by variable outcomes. This study elucidates the potential of PETTICOAT in aortic dissection, emphasizing the determinants that guide patient selection.

METHODS

A retrospective analysis of 60 patients who underwent full PETTICOAT for aortic dissections was conducted. A multivariate logistic regression model identified predictors of favorable aortic remodeling. Patients underwent standardized follow-up with CT scans to assess size, volumetric changes, and anatomical conditions. Selection criteria included full PETTICOAT application and a minimum three-month follow-up. Demographics, preoperative conditions, and procedural details were collected and analyzed.

RESULTS

The analysis identified predictors of favorable aortic remodeling, including age over 60, a larger downstream aorta stent graft, a smaller abdominal aorta (<450mm2), and oral angiotensin II receptor blocker (ARB) administration. Over a median 47.5-month follow-up, survival rates in the favorable remodeling (97.3%) and unfavorable groups (100%) were similar. Downstream aortic event-free survival rates did not significantly differ (89.2% vs. 73.9%), although the unfavorable group had a relatively higher incidence of distal stent-induced new entries (26.1% vs. 8.1%).

CONCLUSIONS

The PETTICOAT concept effectively enhances aortic remodeling in complex aortic dissections. Predictors for favorable remodeling, including age, stent graft sizing, aortic diameter, and ARB therapy, offer insights for optimizing patient selection. This approach improves survival outcomes, mitigates risks associated with untreated aortic segments, and provides a minimally invasive solution for aortic dissections. Despite some outcome variations, the technique holds promise for addressing the challenges of aortic dissections, with the potential for further refinement in patient selection and technique application.

[Malperfusion after Aortic Dissection - Management and Techniques]

Malperfusion is a common complication of aortic dissection and further increases this deadly disease's mortality. An effective treatment strategy requires a timely diagnosis based on the clinical findings and the available instruments, understanding the disease's pathomechanism, recognising the therapy options recommended by the guidelines, and the diagnostic and therapeutic innovations of the area of research. The final treatment decision should be patient- and case-specific. In this work, we have considered malperfusion after aortic dissection, not only as a complication of aortic dissection but as a separate disease and summarise important information that can contribute to efficient therapy decisions in everyday clinical practice.

Predictors for thoracic aortic growth in patients with type B aortic dissection after thoracic endovascular aortic repair

OBJECTIVE

To identify independent predictors of thoracic aortic growth in patients with type B aortic dissection (TBAD) undergoing thoracic endovascular aortic repair (TEVAR).

METHODS

A retrospective analysis of the patients undergoing TEVAR for TBAD or intramural hematoma (IMH) from April 2014 to April 2023 was performed. The baseline morphological data of TBAD was established through computed tomography angiography (CTA) before discharge. Patients were divided into two groups based on aortic growth: growth and no growth. Aortic growth defined as an increase ≥5 mm in thoracic maximal aortic diameter during any serial follow-up CTA measurement. Logistic regression following propensity score matching (PSM) was used to identify independent predictors for aortic growth. Receiver operating characteristic curve and cutoff value of independent predictors were calculated. Linear regression was used to establish a correlation between anatomical variables and follow-up aortic diameter.

RESULTS

A total of 145 patients with TBAD (n = 122) or IMH (n = 23) undergoing TEVAR were included, with a male of 83.4% and a mean age of 56 ± 14.1 years. Patients in growth group and no growth group was 26 (17.9%) and 119 (80.1%), respectively. After using PSM method, matched regression analysis showed residual maximal tear diameter (OR = 0.889, 95% CI 0.830-0.952, p = 0.001) and follow-up aortic diameter (OR = 0.977, 95% CI 0.965-0.989, p < 0.001) were independent predictors for aortic growth. The cutoff value was 8.55 mm for residual tear diameter and 40.65 mm for follow-up maximal aortic diameter. The residual maximal tear diameter showed a linear correlation with follow-up aortic diameter (DW = 1.74, R2 = 6.2%, p = 0.033).

CONCLUSIONS

This study suggested that residual maximal tear diameter >8.55 mm and follow-up aortic diameter >40.65 mm could predict aortic growth in patients with TBAD undergoing TEVAR.

Clinical outcomes and aortic remodeling after Castor single-branched stent-graft implantation for type B aortic dissections involving left subclavian artery

Background

The left subclavian artery (LSA) can be intentionally covered by a stent graft to acquire adequate landing zones for a proximal entry tear near the LSA during thoracic endovascular aortic repair (TEVAR). The Castor single-branched stent graft is designed to treat type B aortic dissection (TBAD) to retain the LSA during TEVAR. This study investigates clinical outcomes, aortic remodeling, and abdominal aortic perfusion patterns after TEVAR with the novel Castor device.

Methods

From November 2020 to June 2023, 29 patients with TBAD involving the LSA were treated with the Castor single-branched stent graft. In-hospital clinical outcome and aortic computed tomography angiography (CTA) data were analyzed. CTA was performed preoperatively and at follow-up to observe stent morphology; branch patency; endoleak; change in true lumen (TL), false lumen (FL), and transaortic diameters; and abdominal aortic branch perfusion pattern.

Results

The technical success rate was 96.6%. One failure was that the branch section did not completely enter the LSA and the main body migrated distally. No in-hospital mortality, paraplegia, or stroke occurred. During follow-up, one type Ib endoleak, four distal new entry tears, and one recurrent type A dissection arose from a new entry tear at the ascending aorta, no stent migration was observed, and the branch patency rate was 100%. At the thoracic aorta, TL diameters significantly increased, FL diameters markedly decreased, and FL was partially or completely thrombosed in most patients at follow-up. At the abdominal aorta, we observed 33.3% of TL growth and 66.7% of TL stabilization or shrinkage. The initial TL ratio at iliac bifurcation negatively predicted abdominal TL growth after TEVAR with a cutoff of 21.0%. Of the 102 abdominal aortic branches, 94.1% of the branches showed no change in perfusion pattern, 3.9% of the branches had an increased TL perfusion, and 2.0% of the branches had an increased FL contribution.

Conclusion

The Castor unibody single-branched stent graft offers an efficient endovascular treatment for TBAD involving the LSA. TEVAR with the Castor device effectively induced thoracic FL thrombosis and thoracic TL enlargement and resulted in abdominal TL growth when the initial TL ratio at iliac bifurcation is less than 21.0%. Abdominal aortic branch perfusion patterns remain relatively stable after TEVAR with the Castor stent graft.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

CLINICAL IMPACT

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

A case of stent-assisted balloon-induced intimal disruption and relamination of distal remaining aortic dissection after the ascending aorta and aortic arch replacement for acute aortic dissection

BACKGROUND

The early survival rate of patients with acute type A aortic dissection (TAAD) has improved remarkably over the past two decades. However, a false lumen may remain after proximal aortic repair and is a potential risk factor for aortic diameter enlargement, aortic rupture, and death in the chronic phase. In the stent-assisted balloon-induced intimal disruption and relamination of aortic dissection (STABILISE) technique, a stent graft is implanted at the proximal part of the aortic dissection, followed by bare-metal aortic stent placement over the distal aortic dissection. Next, an aortic balloon catheter is dilated inside the stent graft and the bare stent to disrupt the intima and collapse the false lumen, immediately restoring uniluminal thoracoabdominal aortic flow. This report describes our experience with the STABILISE technique for a residual aortic dissection after an ascending aorta, and partial aortic arch replacement for acute TAAD resulted in complications.

CASE PRESENTATION

A 60-year-old man presented to our hospital with chest pain, paresthesia, and left lower-limb paralysis. He was diagnosed with acute type A aortic dissection (TAAD) and malperfusion of the left lower limb by computed tomography (CT), and an emergent ascending aorta and partial aortic arch replacement were performed. Immediately after surgery, the left femoral arterial pulse improved, and left lower limb revascularization was deferred. The postoperative course was good; however, back pain and intermittent claudication recurred on the 9th day after surgery. A CT examination revealed persistent antegrade false lumen flow in the descending thoracic aorta through the left subclavian artery dissection and retrograde false lumen flow from the thoracoabdominal segment, resulting in aortic diameter enlargement and narrowing of the true lumen. The symptoms did not improve, and the STABILISE technique was performed on the 12th day after the initial aortic surgery. The patient's subsequent course was good; the back pain and intermittent claudication resolved. The patient was discharged on the 8th day after the STABILISE technique.

CONCLUSIONS

The STABILISE technique can obliterate the false lumen and resolve symptoms associated with a residual false lumen after proximal aortic repair for acute TAAD.

Staged hybrid repair for a patient with chronic type B aortic dissection

Vascular prosthesis replacement and thoracic endovascular repair (TEVAR) are used to treat patients with enlarged chronic type B aortic dissection. A case in which thrombosis of the false lumen was achieved by the staged combination of these two methods is presented. A 41-year-old woman with a thoracoabdominal aortic aneurysm (maximum short diameter 44 mm) identified 5 years earlier was being monitored as an outpatient in our department when she presented with back pain. Computed tomography (CT) showed acute type B aortic dissection (DeBakey type IIIa), which was managed conservatively. When CT showed an aortic dissection with a patent false lumen immediately below the left subclavian artery bifurcation, one-debranching TEVAR was performed to close the entry, along with right axillary artery to left axillary artery bypass surgery. Outpatient CT at 3 months postoperatively showed rapid enlargement in the vicinity of the celiac artery. Thoracoabdominal aortic replacement to prevent rupture was performed, and the patient was then monitored as an outpatient. CT at age 43 years showed enlargement of the residual false lumen. Additional TEVAR was successfully performed. Thus, three-stage treatment was conducted to enlarge the residual false lumen, causing successful thrombosis of the false lumen.

Advanced Endovascular Treatment of Complex Aortic Pathology

Endovascular aortic aneurysm repair and thoracic endovascular aortic repair have been shown to reduce blood loss, operative time, length of hospital stay, mortality, and morbidity compared with open surgical repair for abdominal aortic aneurysms and thoracic aortic aneurysms. However, there are anatomical constraints that limit the application of the endovascular approach in 30% to 40% of patients, including those with short necks, excessive angulation, or aneurysms with the involvement of aortic side branches such as supra-aortic trunks, arch aneurysms, visceral arteries, or internal iliac arteries.

A comparison of endovascular repair to medical management for acute vs subacute uncomplicated type B aortic dissections

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has emerged as a viable option of treatment for uncomplicated type B aortic dissection (UTBAD) due to the potential for inducing favorable aortic remodeling. The aim of this study is to compare outcomes of UTBAD treated medically or with TEVAR in either the acute (1 to 14 days) or subacute period (2 weeks to 3 months).

METHODS

Patients with UTBAD between 2007 and 2019 were identified using the TriNetX Network. The cohort was stratified by treatment type (medical management; TEVAR during the acute period; TEVAR during the subacute period). Outcomes including mortality, endovascular reintervention, and rupture were analyzed after propensity matching.

RESULTS

Among 20,376 patients with UTBAD, 18,840 were medically managed (92.5%), 1099 patients were in the acute TEVAR group (5.4%), and 437 patients were in the subacute TEVAR group (2.1%). The acute TEVAR group had higher rates of 30-day and 3-year rupture (4.1% vs 1.5%; P < .001; 9.9% vs 3.6%; P < .001) and 3-year endovascular reintervention (7.6% vs 1.6%; P < .001), similar 30-day mortality (4.4% vs 2.9%; P < .068), and lower 3-year survival compared with medical management (86.6% vs 83.3%; P = .041). The subacute TEVAR group had similar rates of 30-day mortality (2.3% vs 2.3%; P = 1), 3-year survival (87.0% vs 88.8%; P = .377) and 30-day and 3-year rupture (2.3% vs 2.3%; P = 1; 4.6% vs 3.4%; P = .388), with significantly higher rates of 3-year endovascular reintervention (12.6% vs 7.8%; P = .019) compared with medical management. The acute TEVAR group had similar rates of 30-day mortality (4.2% vs 2.5%; P = .171), rupture (3.0% vs 2.5%; P = .666), significantly higher rates of 3-year rupture (8.7% vs 3.5%; P = .002), and similar rates of 3-year endovascular reintervention (12.6% vs 10.6%; P = .380) compared with the subacute TEVAR group. There was significantly higher 3-year survival (88.5% vs 84.0%; P = .039) in the subacute TEVAR group compared with the acute TEVAR group.

CONCLUSIONS

Our results found lower 3-year survival in the acute TEVAR group compared with the medical management group. There was no 3-year survival benefit found in patients with UTBAD who underwent subacute TEVAR compared with medical management. This suggests the need for further studies looking at the necessity for TEVAR when compared with medical management for UTBAD as it is non-inferior to medical management. Higher rates of 3-year survival and lower rates of 3-year rupture in the subacute TEVAR group compared with the acute TEVAR group suggest superiority of subacute TEVAR. Further investigations are needed to determine the long-term benefit and optimal timing of TEVAR for acute UTBAD.

Balloon Inducted Re-Lamination and False lUmen Thrombosis in Chronic Type B Aortic Dissection: Technique and Long-Term Results

BACKGROUND

To evaluate the safety, feasibility, and effectiveness of the BAlloon Inducted re-Lamination and false lUmen Thrombosis (BAILOUT) as a simple technique to address the retrograde false lumen (FL) perfusion and subsequent aneurysmatic degeneration of the thoracic aorta due to a stent-graft crimped in a small true lumen in chronic Type B dissections.

METHODS

An observational, retrospective, single-center study analyzing a nonconsecutive cohort of 8 patients affected by chronic type B aortic dissections already treated with thoracic endovascular repair and with an FL lumen backflow corrected with BAILOUT between 2006 and 2020. After a standard distal extension of the previously implanted graft, the distal end of the graft area was ballooned to completely rupture the dissection lamella to relaminate the aorta hindering the FL backflow. Computed tomography was routinely performed within the first postoperative week before discharge and then at 3 months, at 6 months, and yearly thereafter. The technical and clinical success rates were analyzed. Primary outcomes were safety and feasibility of the technique, secondary ones included FL thrombosis evaluation, and total aortic diameter analysis at the above-defined levels during the follow-up. Safety was defined if clinical success was reached. Feasibility was intended as technical success obtention.

RESULTS

The technical and clinical success achieved was 100% with the complete interruption of FL backflow stating the safety and feasibility of the BAILOUT technique. No early procedure reinterventions were recorded and during a median follow-up of 62.5 months [interquartile range 43.2-94.1], only 1 death unrelated to the procedure was recorded. Freedom from aortic-related adverse events at 1 month, 3 months, 1 year, 5, and 7 years was 87.5%, 62.5%, 62.5%, 62.5%, and 62.5%, respectively. During the follow-up, no one increment of the diameter of the thoracic aorta was documented and all the patients at 3 years of computed tomography angiography showed a complete FL thrombosis.

CONCLUSIONS

The BAILOUT technique demonstrates to be safe and feasible in this small cohort of patients as a simple and quick way to overcome the issue of FL backflow in chronic type B dissection. Small cohort and retrospective designs were limitations of the study.

A retrospective study of thoracic endovascular aortic repair timing in patients with uncomplicated type B dissection who have a smoking history

Objective

To determine the optimal timing of thoracic endovascular aortic repair (TEVAR) for patients with uncomplicated type B dissections who have a smoking history.

Methods

Data from 308 consecutive patients with uncomplicated type B dissections, who have a smoking history and onset-to-TEVAR time within 90 days, were analyzed. The patients were divided into two groups: Acute and subacute phases. Univariate and multivariate regression analyses were performed. Smooth curve fitting and threshold analysis were performed to characterize the relationship between the onset-to-TEVAR time and follow-up deaths.

Results

There were no significant differences between the two groups. Smooth curve fitting and threshold effect analysis showed that if early TEVAR was performed within 9.4 days from onset, there was better long-term survival and there was no significant difference after 9.4 days.

Conclusion

By studying the relationship between onset-to-TEVAR time and all-cause mortality, we found that early TEVAR may have a lower all-cause mortality rate during follow-up in uncomplicated type B dissection patients who have a smoking history and within 90 days from onset.

Thoracic Endovascular Aortic Repair for Chronic Type B Aortic Dissection: Pre- and Postprocedural Imaging

Aortic dissection is a chronic disease that requires lifelong clinical and imaging surveillance, long after the acute event. Imaging has an important role in prognosis, timing of repair, device sizing, and monitoring for complications, especially in the endovascular therapy era. Important anatomic features at preprocedural imaging include the location of the primary intimal tear and aortic zonal and branch vessel involvement, which influence the treatment strategy. Challenges of repair in the chronic phase include a small true lumen in conjunction with a stiff intimal flap, complex anatomy, and retrograde perfusion from distal reentry tears. The role of thoracic endovascular aortic repair (TEVAR) remains controversial for treatment of chronic aortic dissection. Standard TEVAR is aimed at excluding the primary intimal tear to decrease false lumen perfusion, induce false lumen thrombosis, promote aortic remodeling, and prevent aortic growth. In addition to covering the primary intimal tear with an endograft, several adjunctive techniques have been developed to mitigate retrograde false lumen perfusion. These techniques are broadly categorized into false lumen obliteration and landing zone optimization strategies, such as the provisional extension to induce complete attachment (PETTICOAT), false lumen embolization, cheese-wire fenestration, and knickerbocker techniques. Familiarity with these techniques is important to recognize expected changes and complications at postintervention imaging. The authors detail imaging options, provide examples of simple and complex endovascular repairs of aortic dissections, and highlight complications that can be associated with various techniques. Online supplemental material is available for this article. ^©RSNA, 2022.

Fate and Consequences of the False Lumen after TEVAR in Type B Aortic Dissection

BACKGROUND

Type B aortic dissection (TBAD) occurs due to an entry tear in the intimal layer of the aorta distal to the origin of the left subclavian artery where blood enters the newly formed false lumen (FL) and extends distally or proximally to form a dissection over an indeterminate length of the aorta which, over time, may eventually rupture. Thoracic endovascular aortic repair (TEVAR) aims to seal off the entry tear proximally with the stent-graft, occluding the origin of the dissection and excluding the FL. Nevertheless, in some cases, the perfusion to the FL is maintained, hindering the aortic remodelling process and increasing the risk of aneurysmal degeneration and rupture, particularly in the abdominal aorta where evidence suggest that remodelling is slower. This review examines the long-term effects of a patent or partially thrombosed FL on clinical outcomes following TEVAR in TBAD, also highlighting the pathological processes behind negative aortic remodelling. Another aim of this review is to provide an overview and appraisal of the currently available techniques for managing a patent or partially thrombosed FL to prevent long-term morbidity occurring.

METHODS

A comprehensive literature search was performed using several search engines including PubMed, Ovid, Google Scholar, Scopus, and Embase to identify and extract relevant studies.

RESULTS

Evidence in the literature show that a partially thrombosed FL is more dangerous than a patent FL due to the occlusion of the distal re-entry tears, impeding outflow and increasing mean arterial and diastolic pressures, whereas the latter is decompressed via distal re-entry sites. FL thrombosis and satisfactory remodelling is sometimes achieved in as few as 40% of patients after TEVAR due to the maintained perfusion of the FL either at the level of the thoracic or abdominal aorta. However, although the thoracic aorta is predominantly covered by the TEVAR stent-graft, poorer remodelling and more dilation is seen in the abdominal aorta. Several techniques are available to embolize the FL, including the Provisional Extension to Induce Complete Attachment, Stent Assisted Balloon Induced Intimal Disruption and Relamination in Aortic Dissection Repair, candy-plug, and Knickerbocker techniques.

CONCLUSIONS

The management of TBAD is invariably TEVAR to seal off the proximal entry tear while extending the repair distally to completely exclude the FL. A risk of aortic wall dilatation distal to TEVAR stent-graft remains; hence, regular monitoring and accurate imaging are essential. At present, a patent FL can be treated using a range of different endovascular techniques.

Five-year results of the STABLE II study for the endovascular treatment of complicated, acute type B aortic dissection with a composite device design

OBJECTIVE

To provide the five-year outcomes of the use of a composite device (proximal covered stent-graft + distal bare stent) for endovascular repair of patients with acute, type B aortic dissection complicated by aortic rupture and/or malperfusion.

METHODS

STABLE II was a prospective, multicenter study of the Zenith Dissection Endovascular System (William Cook Europe, Denmark). Patients were enrolled between August 2012 and January 2015 at sites in the United States and Japan. Five-year follow-up was completed by January 2020.

RESULTS

In total, 73 patients (mean age 60.7±10.9 years; 65.8% male) with acute type B dissection complicated by malperfusion (72.6%), rupture (21.9%), or both (5.5%) were enrolled. Patients were treated with either a composite device (79.5%) or the proximal stent-graft alone (no distal bare stent, 20.5%). Dissections were more extensive in patients who received the composite device (408.9±121.3 mm) than in patients who did not receive a bare stent (315.9±100.1 mm). Mean follow-up was 1209.4±754.6 days. Freedom from all-cause mortality was 80.3%±4.7% at one year and 68.9%± 7.3% at five years. Freedom from dissection-related mortality remained at 97.1%±2.1% from one-year through five-year follow-up. Within the stent-graft region, the rate of either complete thrombosis or elimination of the false lumen increased over time (82.1% of all patients at five years vs. 55.7% at first post-procedure CT), with a higher rate at five years in patients who received the composite device (90.5%) compared with patients without the bare stent (57.1%). Throughout follow-up, overall true lumen diameter increased within the stent-graft region, and overall false lumen diameter decreased. At five years, 20.7% of patients experienced a decrease in maximum transaortic diameter within the stent-graft region, 17.2% experienced an increase, and 62.1% experienced no change. Distal to the treated segment (but within the dissected aorta), 23.1% of patients experience no change in transaortic diameter at five years; a bare stent was deployed in all these patients at the procedure. Five-year freedom from all secondary intervention was 70.7%±7.2%.

CONCLUSIONS

These five-year outcomes indicate a low rate of dissection-related mortality for the Zenith Dissection Endovascular System in the treatment of patients with acute, complicated type B aortic dissection. Further, these data suggest a positive influence of composite device use on false lumen thrombosis. Continuous monitoring for distal aortic growth is necessary in all patients.

[Chronic type B aortic dissection-what to do?]

BACKGROUND

Chronic type B aortic dissection requires optimal medical therapy. However, secondary complications like organ or extremity malperfusion or development of aneurysmal dilatation require interventional therapy.

OBJECTIVES

Presentation of different endovascular treatment options for complications of chronic type B aortic dissection.

MATERIALS AND METHODS

Analysis of current literature with regard to indications, techniques, results, and differential indications of interventional techniques for the treatment of chronic type B aortic dissection complications.

RESULTS

Endovascular implantation of an aortic stent graft is interventional standard therapy for treatment of aneurysmal dilatation of the aorta following type B dissection. Technical problems are the proximal and distal landing zones and the treatment of persistent flow in the false lumen.

CONCLUSION

Endovascular treatment of chronic complicated type B aortic dissection is increasingly used compared to open surgical treatment because not only are more complex stent grafts (fenestrated and branched devices) available but also because of newly developed techniques for effective occlusion of flow in the false lumen (e.g., candy plug).

Influence of abdominal aortic calcification on the distal extent and branch blood supply of acute aortic dissection

OBJECTIVE

This study aimed to investigate the influence of abdominal aortic calcification on the distal extent, blood supply, and mid-term outcomes of acute aortic dissection (AAD).

METHODS

This single-centre retrospective study was conducted from August 2014 to May 2021. The aortic calcification index (ACI) was used to evaluate abdominal aortic calcification. The standardized method provided by the Society for Vascular Surgery (SVS) was used to evaluate the distal extent of AAD. Patients were divided into three groups according to the degree of calcification: no calcification (NC), low calcification (LC), and high calcification (HC).

RESULTS

In a cohort of 723 patients, abdominal aortic calcification was present in 424 (58.6%) patients. The prevalence of coronary heart disease increased with the degree of calcification (NC vs. LC vs. HC: 8.4% vs. 9.5% vs. 19.3%, P<0.001). The ACI of the distal extent at zone 9 was higher than that of the distal extent exceeding zone 9 (P=0.001). The proportions of the NC, LC and HC groups with distal extents exceeding zone 9 were 65.9% vs. 56.2% vs. 37.7%, P<0.001. In multivariate logistics analysis, the calcification grades was a protective factor of distal extents exceeding zone 9 (P<0.001, OR=0.592). Hypertension (P=0.019, OR=1.559) and D-dimer (P<.001, OR=1.045) were risk factors. There was a higher proportion of branch-vessels on the abdominal aorta supplied by the true lumen in the calcification group (NC vs. LC vs. HC: 27.8% vs. 43.8% vs. 51.1%, P<0.001). There were no significant differences in the mid-term outcomes among the groups.

CONCLUSIONS

Abdominal aortic calcification could limit the distal extent in patients with AAD and increase the proportion of branch-vessels on the abdominal aorta supplied by the true lumen.

The STABILISE technique to address malperfusion on acute-subacute type B aortic dissections

Endovascular treatment is the current standard of care for complicated acute and subacute type B aortic dissection. Closure of the primary entry tear with thoracic endovascular aneurysm repair (TEVAR) is often insufficient to induce complete false lumen thrombosis and a positive aortic remodeling. Moreover, TEVAR does not solve all the cases of malperfusion. The Provisional ExTension to Induce COmplete ATtachment (PETTICOAT) technique (deploying self-expandable bare metal stents in the true lumen in addition to TEVAR) can re-expand the true lumen, stabilize the lamella and promote aortic remodeling, but it does not recreate a single-lumen aorta and long-term aneurysmal degeneration of the aorta is frequent. Endovascular treatment by means of TEVAR + PETTICOAT does not recreate a single-lumen aorta so long-term aneurysmal degeneration of the aorta is frequent. The stent-assisted, balloon-induced intimal disruption and relamination of aortic dissection (STABILISE) technique may help to this purpose disrupting the intimal lamella and creating a relaminated uni-luminal aorta.

Impact of high-risk features and timing of repair for acute type B aortic dissections

OBJECTIVE

The new Society for Vascular Surgery/Society for Thoracic Surgery reporting standards for type B aortic dissection (TBAD) categorize clinical presentations of aortic dissection into uncomplicated, high-risk features (HRF), and complicated groups. Although it is accepted that complicated dissections require immediate repair, the optimal timing of repair for HRF has yet to be established. This study aims to identify the ideal timing of thoracic endovascular aortic repair (TEVAR) for HRF, as well as outcomes associated with specific HRF.

METHODS

The Vascular Quality Initiative was queried for TEVARs performed for acute and subacute TBAD with HRF from 2014 to 2020. Rupture, malperfusion, and uncomplicated patients were excluded. HRF were defined per the guidelines as refractory hypertension, pain, or rapid expansion/aneurysm of more than 40 mm. The primary outcomes were in-hospital/30-day mortality and 1-year survival with primary exposure variables being days from symptoms to repair and number of HRFs. Secondary outcomes were spinal cord ischemia, stroke, and retrograde type A dissection (RTAD).

RESULTS

Of the 1100 patients who met inclusion criteria, 811 had one HRF, 249 had two, and 40 had three. There were no significant differences in primary or secondary outcomes based on number of HRFs. There were 309 patients who underwent repair at 0 to 2 days, 262 at 3 to 6 days, 270 at 7 to 14 days, and 259 at 15 days or more. TEVAR performed at 15 days or more was independently associated with lower in-hospital/30-day mortality (odds ratio, 0.38; P = .0388) and improved 1-year survival. Postoperative stroke was associated with earlier repair (0-2 days). There was no association of timing of repair with spinal cord ischemia, retrograde type A dissection or reintervention.

CONCLUSIONS

TEVAR for TBAD with HRF delayed at least 15 days from symptom onset is associated with improved survival, supporting the theory that it is best to delay TEVAR until the subacute phase. Additionally, TEVAR delayed at least 3 days is associated with a decrease in stroke. Having more than one HRF was not associated statistically with worse outcomes. Because the classification of HRF is relatively new and without guidelines for repair, this study highlights the risks of early intervention for HRF and suggests that these patients seem to benefit from at least a short stabilization period before TEVAR.

A Novel Solution for Distal Dilation of Chronic Dissection After Repair Involving Visceral Branches: The Road Block Strategy

Aim

Notwithstanding that unprecedented endovascular progress has been achieved in recent years, it remains unclear what is the best strategy to preserve the blood perfusion of abdominal visceral arteries and promote positive aortic remodeling in patients with distal dilatation of chronic aortic dissection in abdominal visceral part (CADAV) after aortic repair. The present study developed a Road Block Strategy (RBS) to solve this conundrum.

Methods and Results

This prospective single-center clinical study included patients suffering from symptomatic distal dilatation of CADAV after aortic repair treated with RBS from January 2015 to December 2019 and followed up regularly for at least 2 years. Stent grafts were implanted first to cover distal tears and expand the true lumen. Device embolization was performed to induce proximal and distal segmental false lumen thrombosis (FLT) apart from the level of the ostia of vital branches. Successful RBS was performed in 13 patients. Significant differences were found in maximum true lumen diameter (p < 0.05), blood flow area in false lumen (FL) (p < 0.001), and the ratio of blood lumen to FL area (p < 0.05) between the pre-procedure and the latest follow-up results. No aortic rupture, vital branches occlusion, thoracic and abdominal pain, or death occurred during hospitalization and follow-up.

Conclusions

Our findings suggest that RBS is feasible in treating distal dilatation of chronic aortic dissection after prior proximal repair, inducing false lumen thrombosis, preventing deterioration of aortic dissection, and maintaining the patency of abdominal visceral arteries.

Hemodynamic Study of Stanford Type B Aortic Dissection Based on Ex Vivo Porcine Aorta Models

Background:

In this study, we aimed to evaluate hemodynamic influence of the dissected aortic system via various ex vivo type B aortic dissection (AD) models.

Methods:

Twenty-four raw porcine aortas were harvested and randomly divided into 4 groups to create various aortic models. Model A was the control group, while models B to D indicated the AD group, where models B and C presented a proximal primary entry with the false lumen (FL) lengths of 15 and 20 cm, respectively, and model D presented a 20 cm FL with a proximal primary entry and a distal reentry. All the aortic models were connected to a mock circulation loop to attain the realistic flow and pressure status. The flow distribution rate (FDR) of the aortic branches was calculated. Doppler ultrasound was applied to visualize the AD structure and to attain the velocity of flow in both the true and false lumens. Several sections of the AD were stained with hematoxylin and eosin for histologic evaluation after the experiment.

Results:

This study demonstrated that higher pressures were found for the AD group compared with the control group. The mean systolic pressures at the inlet of models A to D were 113.34±0.81, 120.58±0.52, 117.76±0.82, and 115.87±0.42 mm Hg, respectively. The FDRs of the celiac artery in models A to D were 8.65%, 8.32%±0.15%, 7.87%±0.13%, and 8.03%±0.21%, respectively. By ultrasound visualization, the velocity of the flow at the entry to the FL in the AD group ranged in 10 to 92 cm/s. The dissection flap presented pulsatile movement, especially in the models B and C which contained 1 primary entry without distal reentries. Histological examinations indicated that AD was located between the intimal and medial layers.

Conclusions:

Our ex vivo models demonstrated that the configuration of the dissected aorta influenced the pressure distribution. Moreover, the dissection flap affected the FDR of the aortic branches that possibly inducing malperfusion syndrome.

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.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

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

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

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

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

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

Identifying risk factors for early neurological outcomes following thoracic endovascular aortic repair using the SUMMIT database

OBJECTIVES

The aim of this study was to assess risk factors for early neurological complications following thoracic endovascular aortic repair (TEVAR) for multiple thoracic aortic diseases using an aggregated dataset.

METHODS

The Study to Assess Outcomes After Endovascular Repair for Multiple Throacic Aortic Disease dataset included data from 6 studies evaluating Zenith thoracic endografts. Post hoc analysis identified early (30-day) neurological complications by TEVAR indication and corresponding risk factors.

RESULTS

The study included 594 TEVAR patients (67% male; mean age 66 ± 15 years) with thoracic aortic aneurysm (n = 329), ulcer (n = 56), acute (n = 126) or non-acute (n = 33) type B aortic dissection (TBAD) or blunt injury (n = 50). Overall early stroke rate was 3.5% (n = 21). Overall early paraplegia and paraparesis rates were 1.3% (n = 8) and 2.5% (n = 15), respectively. Multivariable analysis identified acute TBAD [versus others, odds ratio (OR) = 3.47, 95% confidence internal (CI): 1.41-8.52) and longer procedural time (OR = 1.33, CI: 1.02-1.73) as early stroke risk factors. Risk factors for paraplegia or paraparesis included more endografts deployed (OR = 2.43, CI: 1.30-4.55), older age (OR = 1.05, CI: 1.01-1.10) and higher preoperative serum creatinine (OR = 1.31, CI: 1.05-1.64). Endografts landing proximal to the left subclavian artery (LSA) increased stroke rate (versus distal to the LSA; 6.8% vs 2.3%, P = 0.014). Intraoperative LSA revascularization was performed in 20.9% of patients with endografts proximal to the LSA; revascularization did not significantly alter stroke rate (8.1% with revascularization vs 6.4% without, P = 0.72).

CONCLUSIONS

Acute TBAD and prolonged procedure time increased early stroke risk, while more endografts placed, age and preoperative renal impairment increased early paraplegia or paraparesis risk. For acute TBAD, endograft placement proximal to the LSA, but not LSA patency, increased stroke risk.

The Distance From the Primary Intimal Tear to the Left Subclavian Artery Predicts Thoracic Aortic Enlargement After Thoracic Endovascular Aortic Repair of Type B Aortic Dissection: A Retrospective Cohort Study

PURPOSE

The purpose of this study was to evaluate the association between the distance from the primary intimal tear (PIT) to the left subclavian artery (LSA) (PIT-LSA distance) and the risk of aortic enlargement after thoracic endovascular aortic repair (TEVAR).

METHODS

This is a retrospective cohort study. A total of 228 patients were reviewed from the database of the Registry Of type B aortic dissection with the Utility of STent graft (ROBUST) study performed from January 1, 2011, to December 31, 2016. Of them, 196 patients were eligible for analysis. The PIT-LSA distance was defined as the length from the distal edge of the LSA orifice to the proximal edge of the PIT along the centerline of the true lumen. According to the border between zone 3 and zone 4 of the Ishimaru classification, patients were divided into group A (n = 117, PIT-LSA distance ≤ 2 cm) and group B (n = 79, PIT-LSA distance > 2 cm). Thoracic aortic enlargement (TAE) was defined as a thoracic aortic volume increase of ≥20%. Multivariate Cox regression was used to estimate the association between the PIT-LSA distance and risk of TAE after TEVAR.

RESULTS

The mean age was 52.3 ± 11.6 years, and 88.8% of patients were male. There were no significant differences between groups in demographic and baseline characteristics. The PIT-LSA distance was 1.1 cm (range, -1.6 to 2.0 cm) in group A, and 2.9 cm (range, 2.1-12.6 cm) in group B. TAE occurred in 27 patients in group A, and 6 in group B. The mean follow-up was 12.4 months (range, 0.10-83.1 months) in group A, and 12.63 months (range, 0.10-82.77 months) in group B. The cumulative 12- and 24-month rates of freedom from TAE were 79.0% and 71.3% in group A, versus 92.5% and 92.5% in group B, respectively. Multivariate Cox regression analysis revealed that the PIT-LSA distance was an independent predictor of TAE after TEVAR (adjusted hazard ratio, 0.66; 95% confidence interval, 0.48-0.90; p = 0.009).

CONCLUSION

Patients with a more proximal PIT location have a higher incidence of thoracic aortic enlargement after TEVAR. The location of the PIT in relation to the LSA can be used to identify patients who need closed surveillance after TEVAR or early preemptive intervention.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Risk factors for incomplete thrombosis in false lumen in sub-acute type B aortic dissection post-TEVAR

There is scarce information about the risk factors for incomplete false lumen thrombosis (FLT) among type B aortic dissection (AD) patients, particularly in the sub-acute phase following thoracic endovascular aortic repair (TEVAR). We enrolled consecutive sub-acute type B AD patients at Xinqiao Hospital (Chongqing, China) from May 2010 to December 2019. Patients with severe heart failure, cancer, and myocardial infarction were excluded. The postoperative computed tomography angiography (CTA) data were extracted from the most recent follow-up aortic CTA. Multivariate logistic regressions were applied to identify the association between FLT and clinical or imaging factors. Fifty-five subjects were enrolled in our study. Twelve participants showed complete FLT, and 2 of these died during the follow-up, while 8 patients died in incomplete FLT group. In the multivariate analysis, maximum abdominal aorta diameter (OR 1.20, 95% CI 1.016-1.417 p = 0.032) and the number of branches arising from the false lumen (FL) (OR 15.062, 95% 1.681-134.982 p = 0.015) were significantly associated with incomplete FLT. The C-statistics was 0.873 (95% CI 0.773-0.972) for the model. The FL diameter (p < 0.001) was significantly shorter following TEVAR, while the true lumen diameter (p < 0.001) and maximum abdominal aorta diameter (p = 0.011) were larger after the aortic repair. There were 21.8% of sub-acute type B AD patients presented complete FLT post-TEVAR. Maximum abdominal aorta diameter and the number of branches arising from the FL were independent risk factors for incomplete FLT. The true lumen diameter, maximum abdominal aorta diameter, and FL diameter changed notably following TEVAR.

Distal Aortic Remodeling after Type A Dissection Repair: An Ongoing Mirage

Remodeling is a commonly encountered term in the field of cardiothoracic surgery that is often used to describe various pathophysiological changes in the dimension, structure, and function of various cardiac chambers, including the aorta. Stanford type A or DeBakey type 1 aortic dissection (TAAD) is a perplexing pathologic condition that can present surgical teams with the need to navigate a maze of complex decision-making. Ascending or hemi-arch replacement leaves behind a significant amount of distal diseased aortic tissue, which might have a persistent false lumen or primary or secondary intimal tears (or communications between lumina), which can lead to dilatation of the aortic arch. Unfavorable aortic remodeling is a major cause of distal aortic deterioration after the index surgery. Cardiac surgeons are aware of post-surgical cardiac chamber remodeling, but the concept of distal aortic remodeling is still idealized. The contemporary literature from established aortic centers supports aggressive management of the residual aortic pathology during the index surgery, and with continuing technical advancements, endovascular stenting options are readily available for patients with TAAD or for complicated type B aortic dissection cases. This review discusses the pathophysiology and treatment options for favorable distal aortic remodeling, as well as its impact on mid- to long-term outcomes following TAAD repair.

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.

Dissection length-to-descending thoraco-abdominal aorta length ratio predicts abdominal aortic enlargement after thoracic endovascular aortic repair for type B aortic dissection involving the abdominal aorta

OBJECTIVES

This study was performed to assess the association between the dissection length-to-descending thoraco-abdominal aorta length ratio (LLR) and abdominal aortic enlargement (AAE) (≥20% increase in total abdominal aortic volume) after thoracic endovascular aortic repair (TEVAR) in patients with type B aortic dissection.

METHODS

We retrospectively analysed data from 184 consecutive patients with type B aortic dissection who underwent TEVAR from January 2011 to December 2016 at 4 hospitals as part of the Registry Of type B aortic dissection with Utility of STent graft study. Preoperative and postoperative computed tomography angiography images were reviewed to assess the LLR and AAE. Patients were stratified into tertiles according to the pre-TEVAR LLR: 0.7 to <1.0 (n = 61), 1.0 to <1.2 (n = 61) and 1.2 to <1.6 (n = 62). The thoracic and abdominal aorta were divided by the celiac trunk. The cumulative incidence of AAE was estimated using the Kaplan-Meier method. A multivariable Cox proportional hazards model was used to assess the independent association between the preoperative LLR and the post-TEVAR risk of AAE. The nonlinear relationship between the LLR and the risk of post-TEVAR AAE was fitted by the restricted cubic smoothing spline, and the inflection point on the fitting curve was determined using a piecewise linear regression model.

RESULTS

Baseline demographics, clinical features, preoperative anatomic characteristics and implanted devices were similarly distributed among the pre-TEVAR LLR tertile groups. At 24 months post-TEVAR, the estimated cumulative incidence of AAE significantly differed (P < 0.01) by LLR tertile group: 0.10 [95% confidence interval (CI) 0.00-0.21], 0.65 (95% CI 0.45-0.78) and 0.67 (95% CI 0.40-0.82), respectively. The pre-TEVAR LLR was an independent predictor of post-TEVAR AAE [hazard ratio (per unit increase) 1.03, 95% CI 1.01-1.04] following a nonlinear relationship with an inflection point at LLR = 1.0.

CONCLUSIONS

The risk of post-TEVAR AAE is highest when the length of the dissection is greater than or equal to the length of the descending aorta (LLR ≥ 1.0).

Comparison of diametric and volumetric changes in Stanford type B aortic dissection patients in assessing aortic remodeling post-stent graft treatment

Background

The study aims to analyze the correlation between the maximal diameter (both axial and orthogonal) and volume changes in the true (TL) and false lumens (FL) after stent-grafting for Stanford type B aortic dissection.

Method

Computed tomography angiography was performed on 13 type B aortic dissection patients before and after procedure, and at 6 and 12 months follow-up. The lumens were divided into three regions: the stented area (Region 1), distal to the stent graft to the celiac artery (Region 2), and between the celiac artery and the iliac bifurcation (Region 3). Changes in aortic morphology were quantified by the increase or decrease of diametric and volumetric percentages from baseline measurements.

Results

At Region 1, the TL diameter and volume increased (pre-treatment: volume =51.4±41.9 mL, maximal axial diameter =22.4±6.8 mm, maximal orthogonal diameter =21.6±7.2 mm; follow-up: volume =130.7±69.2 mL, maximal axial diameter =40.1±8.1 mm, maximal orthogonal diameter =31.9+2.6 mm, P<0.05 for all comparisons), while FL decreased (pre-treatment: volume =129.6±150.5 mL; maximal axial diameter =43.0±15.8 mm; maximal orthogonal diameter =28.3±12.6 mm; follow-up: volume =66.6±95.0 mL, maximal axial diameter =24.5±19.9 mm, maximal orthogonal diameter =16.9±13.7, P<0.05 for all comparisons). Due to the uniformity in size throughout the vessel, high concordance was observed between diametric and volumetric measurements in the stented region with 93% and 92% between maximal axial diameter and volume for the true/false lumens, and 90% and 92% between maximal orthogonal diameter and volume for the true/false lumens. Large discrepancies were observed between the different measurement methods at regions distal to the stent graft, with up to 46% differences between maximal orthogonal diameter and volume.

Conclusions

Volume measurement was shown to be a much more sensitive indicator in identifying lumen expansion/shrinkage at the distal stented region.

Unique characteristics of the type B aortic dissection patients with malperfusion in the Vascular Quality Initiative

OBJECTIVE

Type B aortic dissection (TBAD) complicated by malperfusion carries high morbidity and mortality. The present study was undertaken to compare the characteristics of malperfusion and uncomplicated cohorts and to evaluate the long-term differences in survival using a granular, national registry.

METHODS

Patients with TBAD entered into the thoracic endovascular aortic repair/complex endovascular aortic repair module of the Vascular Quality Initiative from 2010 to 2019 were included. The demographic, radiographic, operative, postoperative, in-hospital, and long-term reintervention data were compared between the malperfusion and uncomplicated TBAD groups using t tests and χ² analysis, as appropriate. Overall survival was compared using Cox regression to generate survival curves.

RESULTS

Of the 2820 included patients, 2267 had uncomplicated TBAD and 553 had malperfusion. The patients with malperfusion were younger (age, 55.8 vs 61.2 years; P < .001), were more often male (79.7% vs 68.1%; P < .001), had a higher preoperative creatinine (1.8 vs 1.1 mg/dL; P < .001), had more often presented with an American Society of Anesthesiologists class of 4 or 5 (81.9% vs 58.4%; P < .001), and had more often presented with urgent status (77.4% vs 32.8%; P < .001). In contrast, the uncomplicated TBAD group had had more medical comorbidities, including coronary artery disease and chronic obstructive pulmonary disease, and a larger aortic diameter (4.0 cm vs 4.9 cm; P < .001). The malperfusion group more frequently had proximal zones of disease in zones 0 to 2 (38.6% vs 31.5%; P = .002) and distal zones of disease in zones 9 and above (78.7% vs 46.2%; P < .001), with a greater number of aortic zones traversed (7.7 vs 5.1; P < .001) and a greater frequency of dissection extension into branch vessels (61.8% vs 23.1%; P < .001). Patients with malperfusion also exhibited greater case complexity, with a greater need for branch vessel stenting and longer procedure times. The overall incidence of postoperative complications was greater in the malperfusion group (39.4% vs 17.1%; P < .001) and included a greater rate of spinal cord ischemia (6.3% vs 2.2%; P < .001), acute kidney injury (10.4% vs 0.9%; P < .001), and in-hospital mortality (11.6% vs 5.6%; P < .001). In-hospital reintervention was also greater for the malperfusion patients (14.5% vs 7.4%; P < .001), although the incidence of long-term reinterventions was similar between the two groups (8.7% vs 9.7%; P = .548). A proximal zone of disease in zone 0 to 2 was associated with decreased survival. In contrast, a distal zone of disease in 9 and above, in-hospital reintervention, and long-term follow-up were associated with increased survival. Despite these differences, long-term survival did not differ between the malperfusion and uncomplicated groups (P = .320.) CONCLUSIONS: Patients presenting with TBAD and malperfusion represent a unique cohort. Despite the greater need for branch vessel stenting and in-hospital reintervention, they had similar long-term reintervention rates and survival compared with those with uncomplicated TBAD. These data lend insight with regard to the observed differences between uncomplicated and malperfusion TBAD.

Thoracic Endovascular Aortic Repair With Additional Distal Bare Stents in Type B Aortic Dissection Does Not Prevent Long-Term Aneurysmal Degeneration

PURPOSE

TEVAR (thoracic endovascular aortic repair) + PETTICOAT (Provisional ExTension to Induce COmplete ATtachment) technique has been selectively employed since 2005 at our institution during endovascular treatment of type B aortic dissection (TBD). The aim of this study is to evaluate the long-term (>5 years) clinical results and the evolution of aortic volume.

MATERIALS AND METHODS

All the patients receiving an endovascular treatment for TBD with the PETTICOAT technique were collected in a prospectively maintained database and follow-up computed tomography scan were retrospectively analyzed. Study endpoints included short- and long-term clinical success (absence of need for reintervention) and any major adverse event. The volumes of thoracic and abdominal aorta at long-term follow-up were also analyzed.

RESULTS

Twenty-eight patients received a TEVAR + PETTICOAT and were followed up (median follow-up 85 months). Primary 30-day clinical success rate was 82% with an adverse event rate of 31%; 4 type I endoleak and 1 retrograde dissection were recorded. Secondary mid-term clinical success was 96% while the long-term clinical success rate was 79%. Six cases (21%) received either an open repair or an endovascular repair for a significant distal aortic enlargement at follow-up. With regards to volumetric analysis, an increase of overall (thoracic and abdominal) aortic volume was observed in 8 cases mainly related to an increase (mean: +31%) of the abdominal volume that was observed in 11 cases.

CONCLUSIONS

PETTICOAT technique does not protect from long-term significant aneurysmal degeneration that may require aortic open or endovascular reinterventions. Aortic growth occurs mainly in the bare-stented aorta and thus, life-long surveillance is advisable in these patients.

Adjunctive false lumen intervention for chronic aortic dissections is safe but offers unclear benefit

OBJECTIVE

Adjunctive false lumen embolization (FLE) with thoracic endovascular aortic repair (TEVAR) in patients with chronic aortic dissection is thought to induce FL thrombosis and favorable aortic remodeling. However, these data are derived from small single-institution experiences and the potential benefit of FLE remains unproven. In this study, we examined perioperative and midterm outcomes of patients with aortic dissection undergoing concomitant TEVAR and FLE.* METHODS: Patients 18 or older who underwent TEVAR for chronic aortic dissection with known FLE status in the Society for Vascular Surgery Vascular Quality Initiative database between January 2010 and February 2020 were included. Ruptured patients and emergent procedures were excluded. Patient characteristics, operative details and outcomes were analyzed by group: TEVAR with or without FLE. Primary outcomes were in-hospital post-operative complications and all-cause mortality. Secondary outcomes included follow-up mean maximum aortic diameter change, rates of false lumen thrombosis, re-intervention rates, and mortality.

RESULTS

884 patients were included: 46 had TEVAR/FLE and 838 had TEVAR alone. There was no significant difference between groups in terms of age, gender, comorbidities, prior aortic interventions, mean maximum pre-operative aortic diameter (5.1cm vs. 5.0cm, P=0.43), presentation symptomatology, or intervention indication. FLE was associated with significantly longer procedural times (178min vs. 146min, P=0.0002), increased contrast use (134mL vs. 113mL, P=0.02), and prolonged fluoroscopy time (34min vs. 21min, P<0.0001). However, FLE was not associated with a significant difference in post-operative complications (17.4% vs. 13.8%, P=0.51), length of stay (6.5 vs. 5.7 days, P=0.18), or in-hospital all-cause mortality (0% vs. 1.3%, P=1). In mid-term follow-up (median 15.5months, IQR 2.2-36.2 months), all-cause mortality trended lower, but was not significant (2.2% vs. 7.8%); and Kaplan-Meier analysis demonstrated no difference in overall survival between groups (P=0.23). By Cox regression analysis, post-operative complications had the strongest independent association with all-cause mortality (HR 2.65, 95% CI 1.56-4.5, P<0.001). In patients with available follow-up imaging and re-intervention status, mean aortic diameter change (n=337, -0.71cm vs. -0.69cm, P=0.64) and re-intervention rates (n=487, 10% vs. 11.4%, P=1) were similar.

CONCLUSIONS

Adjunctive FLE, despite increased procedural times, can be performed safely for patients with chronic dissection without significantly higher overall perioperative morbidity or mortality. TEVAR/FLE demonstrates trends for improved survival and increased rates of FL thrombosis in the treated thoracic segment; however, given the lack of evidence to suggest a significant reduction in re-intervention rates or induction of more favorable aortic remodeling compared to TEVAR alone, the overall utility of this technique in practice remains unclear. Further investigation is needed to determine the most appropriate role for FLE in managing chronic aortic dissections.

Adjunctive branch interventions during thoracic endovascular aortic repair for acute complicated type B dissection are not associated with inferior outcomes

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has been shown to effectively treat malperfusion associated with acute type B thoracic aortic dissection (TBAD). A subset of patients might still require adjunctive peripheral or visceral artery branch interventions during TEVAR to remedy persistent end organ malperfusion. Our objectives were to determine the incidence of these adjunctive interventions and to compare the outcomes between patients who had and had not undergone such interventions.

METHODS

We performed a retrospective review of the TEVAR and complex EVAR module of the Vascular Quality Initiative from 2010 to 2019 to identify all patients treated for malperfusion due to acute TBAD. The anatomic branch and procedure performed at TEVAR were recorded. The 30-day mortality, need for reintervention, complication rates, and overall survival were compared between these patients stratified by adjunctive intervention status.

RESULTS

A total of 426 patients had undergone TEVAR for acute TBAD with end organ malperfusion. Of the 426 patients, 126 (29.6%) had undergone 182 adjunctive branch interventions during TEVAR. The most common interventions were stenting (n = 86; 47.3%) and stent grafting (n = 49; 26.9%), with the most common site being the left renal artery (n = 49; 26.9%). The patients in both groups had similar 30-day mortality (12.4% with branch intervention vs 15.6% without; P = .511) and rates of in-hospital reintervention (19.2% with branch intervention vs 20.7% without; P = .732). No differences were found in the rates of postoperative complications or overall survival at 3 years between the two groups.

CONCLUSIONS

Adjunctive peripheral and visceral artery branch interventions in conjunction with TEVAR for acute TBAD with malperfusion occurred in one third of index cases, but did not predispose patients to worse overall outcomes. Adjunctive arterial branch interventions should be included in the treatment paradigm for acute TBAD with end organ malperfusion that does not improve with primary entry tear coverage alone.

Early outcomes associated with use of the Zenith TX2 Dissection Endovascular Graft for the treatment of Stanford type B aortic dissection

OBJECTIVE

To evaluate short term outcomes related to the use of the Zenith TX2 Dissection Endovascular Graft (ZDEG) and the Zenith Dissection Bare stent (ZDES) for the treatment of Stanford type B aortic dissections.

METHODS

This retrospective multicenter case cohort study collated data from 10 European institutions for patients with both complicated and uncomplicated type B aortic dissection treated with ZDEG and ZDES between 2011 and 2018. The primary end point was mortality at 30 and 90 days. Secondary end points included complications related to TEVAR, such as, type Ia endoleak, stroke, paraparesis, paraplegia, and retrograde type A dissection (RTAD). Statistical analysis was carried out using the t test, or one-way analysis of variance and the χ² or Fisher exact tests.

RESULTS

We treated 120 patients (87 male; mean age, 62.7 ± 12.2years) either in the acute 76 (63.3%), subacute 16 (13.3%), or chronic 28 (23.3%) phase. Seven patients (5.8%) died within 30 days after the index procedure and two (1.7%) between 30 and 90 days. There was one instance of postoperative RTAD in a patient treated for rupture. Stroke and paraplegia occurred in three (2.5%) and five (4.2%), patients, respectively. Eight patients (6.7%) had a type Ia endoleak in the perioperative period. There were no instances of paraplegia, no permanent dialysis, and no requirement for adjunctive superior mesenteric or celiac artery stenting in the 33 patients (27.5%) who were treated by concurrent placement of ZDES distal to the ZDEG. The length and distal oversizing of ZDEG components used was less in this group.

CONCLUSIONS

The present series demonstrates a low (<1%) RTAD rate and favorable morbidity and mortality. The lower rate of paraplegia, dialysis, and visceral artery stenting in the cohort that had adjunctive use of ZDES is compelling and merits further assessment.

Stroke rate after thoracic endovascular aortic repair using de-airing of stentgrafts with high-volume of saline solution

Background: Our aim was to determine the rate of ischemic stroke following thoracic endovascular aortic repair (TEVAR) after reducing gas volume released during stentgraft deployment by de-airing of thoracic stentgrafts with high-volume of 0.9% heparinized saline solution. Patients and methods: A single center retrospective analysis of all consecutive patients undergoing TEVAR from 2014 to 2019 was performed. All thoracic stentgrafts were flushed with 120 ml 0.9% heparinized saline solution before implantation, according to our institutional protocol. Endpoints were in-hospital rates of ischemic stroke and spinal cord ischemia (SCI), and all-cause mortality. Results: One hundred and fifty-four patients (mean age: 66.8 ± 13.6 years, 64.9% males) were treated with TEVAR during the study period. Indications for treatment were thoracic aortic aneurysms (n = 75, 48.7%), acute type B aortic dissections (n = 46, 29.9%), aortic arch aneurysms and penetrating aortic ulcers (n = 28, 18.2%), and blunt traumatic aortic injuries (n = 5, 3.2%). Timing of procedure was urgent in 75 patients (48.7%). Proximal landing zone were zone 0-1-2 (n = 75, 48.7%), zone 3 (n = 66, 42.9%) and zone 4 (n = 13, 8.4%). Supra-aortic vessels were revascularized with custom-made fenestrated stentgrafts in 9 patients (5.8%), using chimney technique in 4 patients (2.6%), and with debranching procedures in 19 patients (12.3%). Left subclavian artery was covered without revascularization in 46 patients (29.9%). In-hospital stroke occurred in two patients (1.3%) and SCI in another two patients (1.3%). In-hospital mortality rate was 0.6%. No further in-hospital events were noted. Conclusions: De-airing of stentgrafts with high-volume of 0.9% heparinized saline solution seems to be safe and can be used as an adjunct to keep occurrence of neurological events after TEVAR as low as possible.

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.

Quantification of volume changes in the descending aorta after frozen elephant trunk procedure using the Thoraflex hybrid prosthesis for type A aortic dissection

Background

Frozen elephant trunk (FET) is an established approach to reduce late complications of type A aortic dissection (AADA) by diminishing false lumen perfusion. Currently, surface size of aortic lumina are evaluated using Computed tomography (CT). However, this 2D method is prone to error as it evaluates dissection progression slice by slice. Volume measurement on the other hand can overcome this limitation and deliver better insights in aortic remodeling. Therefore, the aim was to quantify volume changes of the descending and abdominal aorta at short- and mid-term follow-up after FET.

Methods

Between April 2015 and March 2018, 20 patients who underwent surgical repair of AADA using the Thoraflex™ Hybrid Plexus (Vascutek, Terumo Aortic, Scotland) were included in this study. We measured volumetric change before surgical treatment, at discharge, at 12 and at 24 months based on CTAs (Computed tomography angiography). Surfaces and volumes have been analyzed using Aquarius iNtuition (TeraRecon Inc., Foster City, CA, USA).

Results

One hundred fifty-eight volumetric measures were obtained. The findings show a significant increase of volume of the true lumen (TL) while surface measurement of the TL did not show any significant change at other levels besides level C (diaphragm, P=0.00193). Variance analysis showed significant increase of volume, whereas no significant change was seen in false lumen. Post-hoc analysis revealed a significance at 24 months (P=0.047).

Conclusions

Although previous studies outline the clinical benefit of Thoraflex hybrid prosthesis on short-term follow up, this study provides a more precise understanding of aortic remodeling based on volumetric measurement. Thus, quantification of volume changes should be included for the assessment of optimal follow-up timing and consecutive procedure planning.

Covered or Not, Here I Come: Stanford Type B Aortic Dissection Repair With a Covered and Uncovered Stent Hybrid Technique

The complications resulting from aortic dissections are often devastating. Historically, when a Stanford B aortic dissection extended into the visceral abdominal aorta, only surgical management was considered to limit visceral organ malperfusion. Complications of surgical management for Stanford B aortic dissections are as high as 50%. The inherently high complication and mortality rate for any acute aortic dissection, in addition to the complication rates resulting from surgical management, have demonstrated poor outcomes. This is especially true when aortic dissections involve the visceral segment, where thoracic endovascular aortic repair (TEVAR) becomes limited or contraindicated. In the last two decades, various approaches for TEVAR have improved in both endograft design and interventional technique. The current literature demonstrates improved outcomes for patients that receive TEVAR for Stanford B aortic dissections, including those that involve the visceral segment. Despite favorable prognostic advancement in TEVAR, the proven management complexity of Stanford B aortic dissections continue to reflect the pitfalls of the endovascular devices that are currently available. We describe a covered and uncovered stent hybrid technique in patients with complicated Stanford B aortic dissections involving the visceral segment, considering these deficiencies. Hundred percent technical success was demonstrated in the short and mid-term surveillance periods.

Full PETTICOAT in acute type B aortic dissection with patent false lumen may offer positive remodeling for the distal aorta

OBJECTIVE

The provisional extension to induce complete attachment (PETTICOAT) technique is a unique thoracic endovascular aortic repair (TEVAR) for aortic dissection, which consists of proximal descending aortic endografting plus distal bare-metal stenting. This study aimed to investigate the efficacy of the PETTICOAT technique in patients with acute-sub-acute complicated type B aortic dissections. In particular, we compared the remodeling effect of full PETTICOAT covering down to the abdominal aorta with that of simple entry closure.

METHODS

In this retrospective pre-post study, we compared the clinical course of consecutive patients undergoing TEVAR with the PETTICOAT technique in which proximal entry tear was excluded with a covered stent, and extension bare stents were placed down to the abdominal segment for acute-sub-acute complicated type B aortic dissections, between 2015 and 2017, with a control group treated with TEVAR with entry closure between 2011 and 2015. Outcomes included the aortic remodeling rate and the aortic diameter up to 1 year after surgery.

RESULTS

Subjects consisted of 47 patients (21 in full PETTICOAT group, 26 in the simple entry closure group). The remodeling rate of the abdominal aorta in the full PETTICOAT group was significantly higher than in the simple entry closure group (p < 0.05), while that of the thoracic aorta was comparable between the two groups.

CONCLUSIONS

This study suggests that the full PETTICOAT technique achieves better aortic remodeling compared to entry closure alone, and might lead to less reintervention.

Endograft exclusion of the false lumen restores local hemodynamics in a model of type B aortic dissection

OBJECTIVE

Endovascular intervention in uncomplicated type B dissection has not been shown conclusively to confer benefit on patients. The hemodynamic effect of primary entry tear coverage is not known. Endovascular stent grafts were deployed in a model of aortic dissection with multiple fenestrations to study these effects. It is hypothesized that endograft deployment will lead to restoration of parabolic true lumen flow as well as elimination of false lumen flow and transluminal jets and vortices locally while maintaining distal false lumen canalization.

METHODS

Thoracic stent grafts were placed in silicone models of aortic dissection with a compliant and mobile intimal flap and installed in a flow loop. Pulsatile fluid flow was established with a custom positive displacement pump, and the models were imaged by four-dimensional flow magnetic resonance imaging. Full flow fields were acquired in the models, and velocities were extracted to calculate flow rates, reverse flow indices, and oscillatory shear index, the last two of which are measures of stagnant and disturbed flows.

RESULTS

Complete obliteration of the false lumen was achieved in grafted aorta, with normal parabolic flow profiles in the true lumen (maximal velocity, 30.4 ± 8.4 cm/s). A blind false lumen pouch was created distal to this with low-velocity (5.8 ± 2.7 cm/s) and highly reversed (27.9% ± 13.9% reverse flow index) flows. In distal free false lumen segments, flows were comparable to ungrafted conditions with maximal velocities on the order of 7.0 ± 2.1 cm/s. Visualization studies revealed forward flow in these regions with left-handed vortices from true to false lumen. Shear calculations in free false lumen regions demonstrated reduced oscillatory shear index.

CONCLUSIONS

Per the initial hypothesis, endovascular grafting improved true lumen hemodynamics in the grafted region. Just distally, a prothrombotic flow regimen was noted in the false lumen, yet free false lumen distal to this remained canalized. Clinically, this suggests a need for advancing endovascular intervention beyond sole entry tear coverage to prevent further false lumen canalization through uncovered fenestrations.