Stent graft therapy for false lumen aneurysmal degeneration in established type B aortic dissection (FADED) results in differential volumetric remodeling of the thoracic versus abdominal aortic segments

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.

False lumen embolization as a rescue technique in the setting of acute and chronic dissecting aneurysms as adjunct to thoracic endovascular aortic repair

Complicated type B aortic dissection (TBAD) is a life-threatening condition requiring surgical intervention. One such complication in the acute or chronic setting is aneurysmal degeneration. The dissected aortic wall is weakened, and the pressures in the false lumen are often high. In the past decade, thoracic endovascular aortic repair (TEVAR) has become the treatment of choice for TBAD. TEVAR can be complicated by lack of false lumen thrombosis, increasing the risk of death. We present three cases of TBAD with patent false lumens after TEVAR that were treated by false lumen coil embolization.

Total Endovascular Repair With Parallel Stent-Grafts for Postdissection Thoracoabdominal Aneurysm After Prior Proximal Repair

Purpose: To evaluate the safety and efficacy of total endovascular repair with parallel stent-grafts for postoperative residual dissection thoracoabdominal aortic aneurysm (TAAA). Materials and Methods: A retrospective study was undertaken of 21 patients (mean age 64.0±12.5 years; 17 men) undergoing total endovascular therapy with parallel stent-grafts for postdissection TAAA after prior proximal repair between 2014 and 2016. The preoperative minimum true lumen diameter was 12.3±4.8 mm and the mean extent of dissection was 248.1±48.2 mm. Pre-, intra-, and postoperative medical records were reviewed to assess technical success, spinal cord ischemia, patency of target branch arteries, endoleak, and short-term outcomes of this approach. Results: Technical success was achieved in 17 of 21 patients owing to 4 type I endoleaks at the end of the procedures. A total of 70 branch arteries were revascularized and 14 celiac trunks were covered intentionally without reconstruction. Of 7 intraoperative endoleaks, 2 were managed intraoperatively and 5 (4 type I and 1 type II) disappeared spontaneously within 1 month. No spinal cord or abdominal organ or limb ischemia was observed. Mean follow-up was 16.2±6.1 months. No death or type I or III endoleak occurred during the follow-up; 2 type II endoleaks were observed. Nineteen of the 21 false lumens thrombosed, and the total aortic diameter decreased (57.3±8.4 to 55.3±7.4 mm, p<0.01). Three (4.3%) of 70 target branch arteries occluded during follow-up. The cumulative patency of retrogradely and antegradely revascularized branch arteries was 97.3% vs 100% at 12 months and 91.2% vs 100% at 18 months. Conclusion: Total endovascular therapy with parallel stent-grafts could be an effective alternative in treating postdissection TAAA. Further studies with long-term follow-up and larger sample size are recommended to evaluate the technique.

Volumetric analysis of the initial index computed tomography scan can predict the natural history of acute uncomplicated type B dissections

OBJECTIVE

Our objective was to characterize the predictive impact of computed tomography (CT) scan volumetric analysis on the natural history of acute uncomplicated type B aortic dissections (ADs).

METHODS

We conducted a retrospective review of patients with acute type B ADs from 2009 to 2014. On an iNtuition workstation (TeraRecon, Foster City, Calif), volume measurements were obtained using the true lumen volume (TLV), false lumen volume (FLV), and total aortic volume from the left subclavian artery to the celiac artery. Growth rate was calculated as the change in maximal diameter between first and last available CT scans during the time interval. The primary outcome of the study was delayed aortic intervention. P < .05 was considered statistically significant.

RESULTS

During a 5-year period, 164 patients had CT scan evidence of acute type B ADs; 11 patients were excluded for lack of subsequent follow-up imaging; 36 patients who underwent urgent repair (<14 days from presentation) were also excluded. We evaluated a total of 117 patients: 85 patients who did not require intervention and 32 who underwent delayed (>14 days) thoracic endovascular aneurysm repair (29) or open repair (3). Mean age was 66 ± 12 years. Mean TLV/FLV ratio on initial CT scan was significantly higher in patients who did not eventually require an operation (1.55 vs 0.82; P = .02). The mean growth rate was higher in those eventually requiring operation (2.47 vs 0.42 mm/mo; P = .003). Patients were divided into three subgroups on the basis of their initial imaging TLV/FLV ratios (<0.8, 0.8-1.6, and >1.6). There was a significant difference in the growth rates between these three groups (4.6 vs 2.4 vs 0.8 mm/mo; P < .025). Area under the receiver operating characteristic curve analysis revealed that a TLV/FLV ratio <0.8 was highly predictive for requiring an intervention (area = 0.8; sensitivity, 69%; specificity, 84%: positive predictive value, 71%; negative predictive value, 81%), with an odds ratio of 12.2 (confidence interval, 5-26; P < .001). Conversely, a TLV/FLV ratio of >1.6 was highly predictive for freedom from delayed operation (sensitivity, 91%; specificity, 42%; positive predictive value, 61%; negative predictive value, 86%). After Kaplan-Meier analysis, 1-year and 2-year survival free of aortic interventions was 60% and 42% with a TLV/FLV ratio <0.8 and 92% and 82% with a ratio >1.6 (P = .001).

CONCLUSIONS

Initial CT scan volumetric analysis in patients presenting with uncomplicated acute type B ADs is a useful tool to predict growth and need for future intervention.

Morphologic predictors of aortic expansion in chronic type B aortic dissection

Aim

To identify morphologic factors affecting aortic expansion in patients with uncomplicated type B aortic dissections.

Methods

Computed tomography data of 24 patients (18 male; median age: 61 years), diagnosed with acute uncomplicated type B aortic dissections between 2002 and 2013, were retrospectively reviewed. All patients had at least two computed tomography angiography scans and six months of uneventful follow-up. Computed tomography scans were assessed by two independent readers with regard to presence and number of entry tears. Thoracic and abdominal aortic diameters were derived using image processing software.

Results

Twenty-two of 24 patients showed aortic expansion over a median computed tomography angiographic follow-up of 33.2 months. Annual rates showed an increase of 1.7 mm for total aortic diameter, 2.1 mm for the false and a decrease of −0.4 mm for the true lumen. In three patients (12.5%), aortic diameter exceeded 60 mm during follow-up, and all three patients underwent thoracic endovascular aortic repair. Patients with a maximum aortic diameter <4 cm at baseline showed a significantly higher expansion rate compared to cases with an initial maximum aortic diameter of ≥4 cm ( p=0.0471). A median of two entries (range: 1–5) was recognized per patient. Presence of more than two entry tears ( n = 13) was associated with faster overall diameter expansion (mean annual rates: 2.18 mm vs. 1.16 mm; p = 0.4556), and decrease of the cross-sectional surface of the true lumen over time (annual rate for > 2 entries vs. ≤2 entries: −7.8 mm2 vs. +37.5 mm2; p = 0.0369). Median size of entry tears was 12 mm (range: 2–53 mm).

Conclusions

The results presented herein suggest that uncomplicated type B aortic dissection patients with more than two entry tears and/or an initial maximum aortic diameter of<4 cm are at risk for aortic dilatation and, therefore, may require stricter follow-up including the possible need for early intervention.