Current perspectives in acute type B aortic dissections: a literature review

In this new millennial, endovascular strategies have revolutionized the treatment of acute type B aortic dissection (aTBAD). With reduced in-hospital mortality and good long-term outcomes TEVAR has become the gold standard for the treatment of complicated dissection and is gaining increasing support for its preventive applicability in some uncomplicated dissections. With this new paradigm came a shift of the treatment goal where just covering the entry tear is not enough and instead achieving long-term positive thoracoabdominal remodeling is needed. More extensive approaches with composite device designs (covered stent graft and bare metal stent) emerged to answer this aortic conundrum. At 5-year of follow-up, "Provisional ExTension To Induce COmplete Attachment technique" (PETTICOAT) and its evolution "Stent assisted balloon induced intimal disruption and relamination in aortic dissection repair" (STABILISE) seem to be safe techniques that can allow, when anatomically feasible, excellent aortic remodeling and, in some cases, even the healing of the dissection. Nevertheless, STABILISE results, although promising, are mostly based on small series and therefore need to be validated by analyzing medium-long-term results from the international registry. Given the plethora of new data and the disparity of expert opinions on the best treatment to adopt, in this review we aim to summarize the current knowledge on the results of these different strategies for acute TBAD.

Risk Factors for Incomplete Aortic Remodeling With Stent-Assisted Balloon-Induced Intimal Disruption and Relamination in Aortic Dissection Repair for Complicated Aortic Dissection: Results of a Multicenter Study

PURPOSE

The STABILISE technique has extended the treatment of aortic dissection to the thoracoabdominal aorta to achieve complete aortic remodeling. The aim of this multicenter study was to analyze the short- and midterm anatomical results of the STABILISE technique.

MATERIALS AND METHODS

We retrospectively analyzed patients treated with the STABILISE technique for complicated aortic dissection at 3 French academic centers. The aortic diameter at different levels was measured preoperatively, postoperatively, and at 1 year.

RESULTS

Between 2018 and 2020, 58 patients, including 47 men (average patient age: 60±11 years), were treated for type B aortic dissection in 34 cases and residual aortic dissection after type A repair in 24 cases. Three (5.2%) patients died postoperatively. Complete aortic remodeling (false lumen thrombosis and complete reapposition of the intimal flap) was achieved in 45/55 patients (81.8%), and false lumen thrombosis in the thoracic aorta was achieved in 52/55 patients (94.5%). At 1 year, with a computed tomographic (CT) scan available for 98.2% (54/55) of patients, we observed a significant decrease in the maximal thoracic aortic diameter and a significant increase in the aortic diameter at the bare-stent level compared with the preoperative CT scan. Severe aortic angulation (p=0.024) was a risk factor for incomplete aortic remodeling and significantly increased the aortic diameter (p=0.032). Chronic aortic dissection was associated with an increased risk of incomplete aortic remodeling (p=0.002).

CONCLUSIONS

STABILISE for complicated aortic dissection results in false lumen thrombosis, complete reapposition of the intimal flap, and a decrease in the maximum aortic diameter in most cases. Incomplete reapposition of the intimal flap, which is more frequent in cases of chronic aortic dissection and severe aortic angulation, is a risk factor for a significant increase in the aortic diameter at the bare-stent level, and this risk justifies close follow-up and better patient selection.

CLINICAL IMPACT

STABILISE technique for complicated aortic dissection results in false lumen thrombosis, complete aortic remodeling and a decrease in the maximum aortic diameter in most cases. At the bare-stent level, incomplete reapposition of the intimal flap, more frequent in chronic aortic dissection and severe aortic angulation, is a risk factor for an increased aortic diameter. This finding justifies close follow-up and better patient selection; thus, the STABILISE technique should be used with care in chronic aortic dissection and severe aortic angulation.

STOP-Bang Questionnaire Is Associated With Aortic Remodeling in Patients With Acute Type B Aortic Dissection Undergoing Standard Thoracic Endovascular Aortic Repair

PURPOSE

To determine whether the STOP-Bang questionnaire, which is a tool for evaluating obstructive sleep apnea, is associated with aortic remodeling after thoracic endovascular aortic repair (TEVAR) in patients with type B aortic dissection (TBAD).

METHODS

Patients with TBAD who underwent standard TEVAR at our center from January 2015 to December 2020 were enrolled. For the included patients, we recorded baseline characteristics, comorbidities, preoperative computed tomographic angiography findings, procedure details, and complications. The STOP-Bang questionnaire was administered to each patient. Total scores comprised points for 4 yes/no questions and 4 clinical measurements. STOP-Bang ≥5 and STOP-Bang <5 groups were then created using the STOP-Bang total scores. We evaluated aortic remodeling 1 year after discharge and the reintervention rate, as well as false lumen complete thrombosis (FLCT) and non-FLCT length.

RESULTS

Fifty-five patients were enrolled in the study; STOP-Bang <5, n=36, and STOP-Bang ≥5, n=19. Compared with the STOP-Bang ≥5 group, the STOP-Bang <5 group achieved statistically significantly higher descending aorta positive aortic remodeling (PAR) rates in zones 3 to 5 (zone 3: p=0.002; zone 4: p=0.039; zone 5: p=0.023), higher total descending aorta-PAR rate (66.7% vs 36.8%, respectively; p=0.004), and lower reintervention rate (8.1% vs 38.9%, respectively; p=0.005). In the logistic regression analysis, STOP-Bang ≥5 had an odds ratio of 0.12 (95% confidence interval: 0.03-0.58; p=0.008). There was no significant difference in overall survival between the groups.

CONCLUSION

STOP-Bang questionnaire scores were associated with aortic remodeling after TEVAR in patients with TBAD. Increasing the frequency of surveillance after TEVAR might be beneficial in these patients.

CLINICAL IMPACT

We analysed aortic remodelling 1 year after thoracic endovascular aortic repair (TEVAR) in acute type B aortic dissection (TBAD) patients with STOP-Bang < 5 and STOP-Bang ≥ 5. Aortic remodelling was better, and the reintervention rate was higher in patients with STOP-Bang < 5 compared with patients with STOP-Bang ≥ 5. In patients with STOP-Bang ≥ 5, aortic remodelling was worse in zones 3-5 compared with zones 6-9. This study suggests that the STOP-Bang questionnaire results is associated with aortic remodelling after TEVAR in patients with TBAD.

Evaluation of Remodeling of Visceral Arteries and Impact on Renal Function Post-endovascular Repair of Type B Aortic Dissection Vis-A-Vis Baseline Visceral Artery Morphology

PURPOSE

To evaluate the remodeling of visceral arteries post-endovascular repair (TEVAR) of type B aortic dissection and to investigate interval change in renal volume and estimated glomerular filtration rate (eGFR) vis-a-vis baseline visceral artery morphology.

MATERIALS AND METHODS

All patients of type B aortic dissection who underwent TEVAR with a baseline and follow-up CT during the study period were included. Baseline morphology of visceral arteries (celiac, superior, and inferior mesenteric artery and bilateral renal artery) were classified into 7 patterns depending upon the origin of the artery (from true/false lumen) and the extension of dissection flap, while occluded vessels were categorized as pattern 8.

RESULTS

One hundred and thirty-two branches were analyzed in 25 patients (23 males; mean age: 50.1 years) with a mean follow-up of 386 days. 51 visceral branches were arising from the true lumen without any stenosis. Of the remaining 81 branches, 48 showed favorable remodeling (P = .0001). The highest incidence of favorable remodeling was observed in arteries arising from the true lumen (pattern 2,3: 44/48; 91.6%) whereas only one thrombosed and artery arising from the false lumen each (pattern 5 and 8) showed favorable remodeling. Kidneys perfused by false lumen or occluded renal artery suffered statistically significant volume loss compared to kidneys perfused by true or both lumens (-16.5% vs .2%; P = .01); however, the change in eGFR failed to reach statistical significance.

CONCLUSION

Visceral arteries arising from the true lumen are more likely to undergo favorable remodeling. The kidneys supplied by false lumen or by occluded renal artery suffer significantly more volume loss after TEVAR.

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.

Staged hybrid single lumen reconstruction (TIGER) with bilateral subclavian transposition coupled with thoracic endovascular aneurysm repair in the management of acute symptomatic complex type B aortic dissection in a patient with arteria lusoria

We present a 54-year-old Caucasian woman, who presented with acute symptomatic type B aortic dissection with deteriorating renal function. She was a known smoker with a 2-year history of dysphagia. CT angiography documented the artery of lusoria arising from the mid-thoracic aorta, aneurysmal dilation of her descending aorta, and kinetic and static flaps around her visceral ostia. The patient was managed by staged hybrid single lumen reconstruction and bilateral subclavian to carotid transpositions. During follow-up, there was no aortic rupture or retrograde type A dissection. There were no renal, visceral, cardiac, pulmonary or spinal complications. The patient went off her antihypertensive medication with a normal estimated glomerular filtration rate and accelerated aortic modulation.

Balloon Endoclamping for Postdissection Infrarenal Aorto-Iliac Aneurysm Repair

BACKGROUND

Isolated post dissection infrarenal and iliac aneurysm is a rare condition that often requires surgical treatment. Surgical repair should involve the replacement of the aneurysmal segments and a wide fenestration in the residual proximal untreated abdominal aorta. However, in these patients proximal aortic clamping may be challenging. Indeed, infrarenal clamping may hamper an appropriate fenestration in the proximal dissecting lamella, and suprarenal or supraceliac clamping can be dangerous and highly demanding, especially in acute and subacute patients. Here we report our initial experience with a balloon endoclamping technique.

MATERIAL AND METHODS

Our technique includes 1) direct aortic true lumen catheterization, 2) balloon endoclamping of the proximal thoracic aorta, 3) wide fenestration of the infrarenal aorta followed by external clamp positioning, 4) infrarenal aorta and iliac artery reconstruction.

RESULTS

Between October 2018 and November 2019, 4 patients (male n = 4, median age 57 years) underwent postdissection iliac aneurysm repair in our institution. All patients had previously undergone emergent thoracic aorta repair. Postoperative courses were uneventful in all cases. At a median FU of 13 months, all patients remain well, with stable diameters in visceral aorta.

CONCLUSIONS

In our initial experience, proximal aortic endoclamping appeared to be a safe technique associated with promising results. This approach may facilitate proximal aortic clamping and allow for a wide aortic fenestration. Further larger clinical trials are needed to validate our preliminary observations.

One-Year Single-Center Results of the Multilayer Flow Modulator Stents for the Treatment of Type B Aortic Dissection

Purpose

To report a single-center series of patients with type B aortic dissection treated with the Multilayer Flow Modulator (MFM).

Materials and Methods

Over a 36-month period, 23 patients (median age 53 years; 20 men) with complicated type B aortic dissections (2 acute, 5 subacute, and 16 chronic) were treated with the MFM. Primary endpoints of rupture or dissection-related death, overall mortality, and reintervention were evaluated using the Kaplan-Meier method; estimates for freedom from the endpoints are reported with the 95% confidence interval (CI). Secondary outcomes included technical success, adverse events, and aortic remodeling. Clinical and imaging data were collected preoperatively, directly postoperatively, and annually to 36 months for analysis using computational fluid dynamics (CFD).

Results

Initial technical success was 91.3%. The estimates of the endpoints at 12 months were 100% for freedom from rupture or aortic-related death, 95.7% for freedom from overall mortality, and 91.3% for freedom from reintervention. No device-related neurological or systemic complications occurred, and no additional reinterventions were needed during follow-up. A total of 144 branches overstented by the MFM remained patent. Morphologic analysis of the aortic dissection showed progressive true lumen volume increase (75.9%, p<0.001) with concomitant false lumen volume decrease (42.8%, p<0.001); the CFD analyses showed increased laminar flow.

Conclusion

In the current series, the MFM provided a safe and feasible treatment option for complicated acute, subacute, and chronic type B aortic dissections, with high technical success, low mortality, and active aortic remodeling. Further studies should elucidate the long-term safety of the MFM and its effectiveness in a larger patient cohort.