Aortic Remodeling in Type B Aortic Dissection: Effects of Endovascular Stent-Graft Repair and Medical Treatment on True and False Lumen Volumes

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.

Aortic remodeling in aortic dissection after frozen elephant trunk: overcoming the challenges

The introduction of the single-step hybrid frozen elephant trunk (FET) procedure expanded the surgeon's armamentarium in managing aortic dissection (AD). This is evident by the reduction in mortality and complication rates associated with conventional techniques used to repair ADs. Although FET still carries a risk of certain complications, it has been associated with excellent aortic remodeling following the procedure. The main scope of this review is to evaluate aortic remodeling in aortic dissection after FET as well as to highlight the challenges that may arise and ways to overcome them. A comprehensive literature search was conducted on multiple electronic databases including PubMed, Ovid, Scopus and Embase to highlight the evidence in the literature on aortic remodeling in aortic dissection after FET. The FET procedure promotes excellent long-term remodeling, this is seen in the substantial increase in the size of the true lumen along with the decrease in that of the false lumen (FL), in addition to significant FL thrombosis. However, this occurs to a lesser extent more distally at the level of the abdominal aorta. Negative remodeling may present a major challenge to the process of aortic remodeling, nevertheless, this can be overcome with endovascular reintervention which has demonstrated highly favorable results. Additionally, the choice of FET graft, in terms of type and length, seems to influence outcomes. Namely, the Thoraflex™ Hybrid graft can be considered the superior graft on the global market. On the other hand, there seems to be a debate in the literature on the optimal FET graft length. The FET procedure has revolutionized the field of aortovascular surgery and promotes excellent long-term aortic remodeling. Negative remodeling can occur but can also be favorably overcome with endovascular reintervention. Finally, the choice of FET graft may also influence results, thus, should be taken with great care.

Aortic remodeling, reintervention, and survival after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection: Midterm results

Objectives

To investigate the midterm results after zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection.

Methods

Between October 2014 and April 2021, 196 patients underwent zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection. The true lumen area, aortic lumen area, and false lumen status were assessed at four aortic levels, the proximal and distal descending thoracic aorta (level A and level B, respectively), celiac artery branching (level C), and terminal aorta (level D). Aortic remodeling (postoperative area as a percentage of the preoperative area) was classified into 3 groups, positive (true lumen area ≥120% with aortic lumen <120% or true lumen area ≥80% with aortic lumen <80%), minimal (80% ≤ true lumen area and aortic lumen area <120%), and negative remodeling (all other changes).

Results

In-hospital mortality was 13 (6.6%) patients. The overall survival rate was 85.1% at 5 years. The freedom from distal aortic reintervention was 89.9% at 5 years. The prevalence of completely thrombosed or obliterated false lumen at 2 years was 96.8% at level A, 88.4% at level B, 47.2% at level C, and 27.6% at level D. The prevalence of positive aortic remodeling at 2 years was 84.7% at level A, 75.0% at level B, 29.2% at level C, and 16.7% at level D.

Conclusions

Zone 0 arch repair with frozen elephant trunks for acute type A aortic dissection can avoid invasive aortic arch resection and facilitate aortic remodeling of the descending thoracic aorta. The FET effect on aortic remodeling is limited at the aortic level below the FET stent end.

Systematic review and meta-analysis of current evidences in endograft therapy versus medical treatment for uncomplicated type B aortic dissection

OBJECTIVE

Best medical therapy (BMT) should be recommended for treating uncomplicated Stanford type B aortic dissection (uSTBAD), whereas thoracic aortic endovascular repair (TEVAR) has been controversial for uSTBAD.

METHODS

In this paper, a meta-analysis was conducted on all available randomized controlled trials and observational studies that evaluated the relative benefits and harms of TEVAR and BMT for the management of patients suffering from uSTBAD. Primary endpoints consisted of early adverse events, long-term adverse events and aortic remodeling. In addition, Risk difference (RD) or Odds ratios (OR) with 95% confidence intervals (CI) were estimated. The random effects model or the fixed-effects model was used in accordance with the 50% heterogeneity threshold.

RESULTS

Seven observational studies and two RCT studies from 11 articles that contained 15066 patients suffering from uSTBAD (1518 TEVARs) met the inclusion criteria. For early outcomes, no significant differences were found between the TEVAR group and the BMT group in aortic rupture, retrograde dissection, paraplegia/paraparesis, reintervention, aorta-related death and all caused death. In the long run, the TEVAR group was found to have a significantly lower incidence of adverse events, which included aortic rupture (OR:0.26, CI:0.16∼0.42, P<0.05; heterogeneity: P=0.90, I²=0%), reintervention (OR:0.45, CI:0.26∼0.75, P<0.05; heterogeneity: P=0.17, I²=41%), aorta-related death (OR:0.27, CI:0.18∼0.42, P<0.05; heterogeneity: P=0.61, I²=0%) and all caused death (OR:0.52, CI:0.42∼0.66, P<0.05; heterogeneity: P=0.05, I²=53%) as compared with the BMT group. Moreover, in compared with BMT, TEVAR was found to significantly contribute to the complete thrombosis of thoracic false lumen (OR:55.34, CI:34.32∼89.21, P<0.05; heterogeneity: P=0.97, I²=0%) and aortic regression (true lumen expansion and false lumen shrinkage).

CONCLUSIONS

Although early endovascular repair of uSTBAD does not outperform BMT, its implementation is found to be necessary to facilitate the long-term prognosis. Accordingly, if early TEVAR is to be deferred, close follow-up is critical to allow for timely reintervention.

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.

A New Era of Diagnosis and Therapy in Acute Aortic Syndromes: The Mainz-Essen Experience (Part II)-Management and Outcomes

Over the years, the cardiovascular department of Johannes Gutenberg University in Mainz-West-German Heart Centre in Essen (Germany) designed and implemented the hybrid operating room (2003) along with advanced endovascular and surgical procedures, including the frozen elephant trunk technique. For the study purpose, the Mainz-Essen experience on acute aortic syndromes was summarized by considering original articles from single-center or multicenter studies performed at West German Heart Centre, Essen, Germany, or at the cardiovascular department of Johannes Gutenberg University, Mainz, Germany. We present the 35-year-long Mainz-Essen research, education, and patient management journey in creating an integrated multidisciplinary "Aortic Center" in the heart of Europe.

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.

Impact of high blood pressure variability on the occurrence of acute type B aortic dissection

Background

Acute type B aortic dissection is a life-threatening medical emergency, and hypertension is believed to be an important predictor of aortic dissection; the impact of blood pressure variability on the onset and development of aortic dissection has attracted increasing attention.

Methods

A total of 120 acute type B aortic dissection patients and 57 hypertensive patients without aortic dissection were consecutively enrolled and retrospectively reviewed between January 2013 and November 2015. There were 60 acute type B aortic dissection patients in both high and low blood pressure variability groups.

Results

Blood pressure variability showed higher diagnostic value than hypertension in aortic dissection, and the best threshold of blood pressure variability is 5.71 mmHg. By performing multivariable logistic regression, we found that the history of hypertension was likely to be a risk factor of blood pressure variability (95% CI: 1.155–6.422, P = 0.022). Nine patients from high blood pressure variability group and two from low blood pressure variability group ( χ2 = 4.90, P = 0.027) received emergency surgery within 24 hours after admission. The presence of multiple tears (>2, 55.0% vs. 45.0%, P = 0.001), configuration of the false lumen (spiral false lumen) (50.0% vs. 21.7%, P = 0.001), the diameter of the false lumen (49.6 ± 15.0 mm vs. 37.6 ± 10.8 mm, P < 0.001), the false/true lumen ratio (1.53 ± 1.02 vs. 0.929 ± 0.733, P < 0.001), and the number of visceral arteries involved (1.75 ± 0.942 vs. 0.800 ± 0.927, P < 0.001) showed significant differences between high and low blood pressure variability groups. Nine (30%) patients from the high blood pressure variability group showed a maximum diameter of false lumen over 60 mm, while none was found in the low blood pressure variability group.

Conclusions

High blood pressure variability, the presence of multiple tears (>2), the configuration of false lumen, the diameter of the false lumen, false/true lumen ratio, and the number of visceral arteries involved were independent risk factors for acute type B aortic dissection.

Expanded Petticoat technique to promote the reduction of contrasted false lumen volume in patients with chronic type B aortic dissection

OBJECTIVE

This study examined the outcomes of our novel concept of expanded provisional extension to induce complete attachment strategy (Petticoat) for safety, durability, and remodeling of chronic type B dissections.

METHODS

Twenty patients with chronic type B aortic dissection with aneurysmal degeneration qualified for an expanded Petticoat strategy (stent graft in the thoracic, plus additional distal bare stent into the abdominal and infrarenal aorta, followed by parallel stent grafts into common iliac arteries). Computed tomography was performed preoperatively and at 1, 6, and 12 months after surgery.

RESULTS

The primary technical success was 100%. The 30-day mortality rate was 0%. At 12 months, favorable aortic remodeling and complete false lumen (FL) thrombosis were noted as 100% in the thoracic and infrarenal aorta. The volume of contrast-enhanced FL decreased from 186 ± 75.4 mL all along the dissection preoperatively (range, 70-360 mL), to 6.32 ± 5.4 mL postoperatively (range, 0.0-19.6 mL) and was only observed in the visceral aorta (P = .000089). Despite persistent flow in a small area of the FL, the maximal aortic size was stable in follow-up. Neither paraplegia nor visceral branch occlusion were noted in the follow-up.

CONCLUSIONS

The treatment of aortic dissections with an expanded Petticoat strategy seems to be safe and offers good early results. It significantly reduced the volume of contrast enhanced FL. Further investigation of any subsequent results will be necessary.

How does descending aorta geometry change when it dissects?

OBJECTIVES

Thoracic endovascular aortic repair is the treatment of choice in complicated acute type B aortic dissection. How to infer predissection aortic diameter is not well understood. Our aim was to delineate changes in descending aortic geometry due to dissection.

METHODS

Five tertiary centres reviewed their acute aortic dissection type B databases containing 802 patients. All patients who had undergone computed tomography angiography less than 2 years before and immediately after aortic dissection onset were included. We compared the aortic geometry before and after the dissection onset.

RESULTS

Altogether 25 patients were included [median age 60 (first quartile 52, third quartile 72) years; 60% men]. In all except 1 patient, the maximum descending aortic diameter was less than 45 mm before aortic dissection onset. The largest increase in diameter induced by the dissection was observed in the proximal descending aorta 28.2 (25.1, 32.1) vs 34.6 (31.3, 39.1) mm (+6.4 mm; +23%; P < 0.001). The thoracic descending aortic length increased after the dissection onset [253.3 (229.3, 271.9) vs 261.3 (247.9, 285.4) mm; P = 0.003]. The predissection aortic diameter of the proximal thoracic descending aorta was 7.9 (5.2, 10.7) mm larger (P < 0.001) than the post-dissection area-derived true-lumen diameter and 2.5 (1.3, 6.1) mm larger than the maximum true-lumen diameter (P < 0.001).

CONCLUSIONS

Type B aortic dissection increases the diameter, length and volume of the descending thoracic aorta. The predissection aortic diameter most closely resembles the post-dissection maximum diameter of the true lumen.

Favorable remodeling after hybrid arch debranching and modified provisional extension to induce complete attachment technique in type a aortic dissection: A case report

RATIONALE

Type A aortic dissection (TAAD) usually requires emergency open repair of the ascending aorta. In cases of diffuse dissection that spreads along the descending and abdominal aorta (type I, DeBakey classification), the risk of aneurysmal degeneration varies between 30% and 50% during 5 years and increases even higher during a longer follow-up. Those patients might require complex intervention to prevent aortic rupture. A combination of hybrid arch debranching and the extended provisional extension to induce complete attachment (e-PETTICOAT) technique might be an available alternative in such cases. This is the first report of the successful use of the e-PETTICOAT technique for treating degenerative, diffuse TAAD.

PATIENT CONCERNS

Acute chest pain and syncope were the initial symptoms of diffuse TAAD in our 66-year-old female patient. Open replacement of the ascending aorta followed by surgical arch debranching was performed as a staged procedure. Unfortunately, progressive aneurysmal degeneration was revealed 6 months later in the thoracic, abdominal, and infrarenal aorta with the recurrence of chest and lumbar pain.

DIAGNOSES

Computed angiotomography revealed severe aneurysmal degeneration of aortic dissection in the thoracic and abdominal aorta.

INTERVENTION

The e-PETTICOAT enabled good remodeling and stopped degeneration.

OUTCOME

At the 2-year follow-up, good remodeling with complete false lumen thrombosis and a stable aortic size were confirmed.

LESSON

Lifelong follow-up in extensive TAAD should be considered. The e-PETTICOAT technique is an available alternative to fenestrated endovascular aortic repair for degenerative TAAD, as it promotes favorable remodeling after successful surgery of the ascending aorta.

Endovascular Treatment of Various Aortic Pathologies: Review of the Latest Data and Technologies

The technologies and innovations applicable to endovascular treatment for complex aortic pathologies have progressed rapidly over the last two decades. Although the initial outcomes of an endovascular aortic repair have been excellent, as long-term data became available, complications including endoleaks, endograft migration, and endograft infection have become apparent and are of concern. Previously, the indication for endovascular therapy was restricted to descending thoracic aortic aneurysms and abdominal aortic aneurysms. However, its indication has expanded along with the improvement of techniques and devices, and currently, it has become possible to treat pararenal aortic aneurysms and Crawford type 4 thoracoabdominal aortic aneurysm (TAAA) using the off-the-shelf devices. Additionally, custom-made devices allow for the treatment of arch or more extensive TAAAs. Endovascular treatment is applied not only to aneurysms but also to acute/chronic dissections. However, long-term outcomes are still unclear. This article provides an overview of available devices and the results of endovascular treatment for various aortic pathologies.

Complete Shrinkage of the Obliterated False Lumen After Open and Endovascular Chronic Aortic Dissection Stanford Type A Repair

A 48-year-old man was admitted to our hospital with chronic aortic dissection Stanford Type A. His diagnosis was confirmed by chest multi-detector computed tomography (CT). The patient underwent combined (i.e., hybrid) open and endovascular repair (frozen elephant trunk) in a one-stage operation with moderate hypothermic circulatory arrest and antegrade cerebral perfusion. His postoperative course was uneventful, and he was discharged home on postoperative day 9. At 2-year follow-up, chest CT angiography revealed complete shrinkage of the obliterated false lumen in the distal aortic arch and descending thoracic aorta.

Impact of Preoperative Anemia and Postoperative Hemoglobin Drop on the Incidence of Acute Kidney Injury and In-Hospital Mortality in Patients With Type B Acute Aortic Syndromes Undergoing Thoracic Endovascular Aortic Repair

BACKGROUND

The impact of preoperative anemia and postoperative hemoglobin (Hb) drop on the incidence of acute kidney injury (AKI) after thoracic endovascular aortic repair (TEVAR) for type B acute aortic syndromes (AAS) as well as their prognostic value is unknown.

METHODS

This retrospective study included 144 patients with type B AAS undergoing TEVAR at our center. Preoperative anemia was classified as no/mild (Hb ≥ 12.0 g/dL in men; ≥11.3 g/dL in women), moderate (Hb 10.80-11.99 g/dL in men; 10.23-11.29 g/dL in women), and severe (<10.80 g/dL in men; <10.23 g/dL in women). Postoperative Hb drop was classified as mild (<2 g/dL), moderate (2-4 g/dL), and severe (>4 g/dL). End points of the study were postoperative AKI and in-hospital mortality.

RESULTS

Postoperative AKI was higher in the severe and moderate anemia groups than the no/mild anemia group (63.2%, 52.0%, and 31.0%, respectively, P = .01). In-hospital mortality and AKI were higher in patients with severe postoperative Hb drop (40.9% and 86.4%) than patients with moderate (6.9% and 36.2%) and mild (4.7% and 25.0%) postoperative Hb drop (both P < .001). Postoperative Hb drop (odds ratio [OR]:1.67, P = .036), postoperative Hb levels (OR: 0.57, P = .025), and mesenteric ischemia (OR: 4.65, P = .044) were identified as independent predictors of in-hospital mortality. Preoperative Hb (OR: 0.26, P = .001), postoperative Hb drop (OR: 4.34, P < .001), contrast medium (OR: 1.82, P = .004), and diabetes mellitus (OR: 3.79, P = .001) were independent predictors of AKI. At follow-up, anemia and postoperative Hb drop were not associated with increased mortality.

CONCLUSION

Preoperative Hb and postoperative Hb drop were significant risk factors for AKI. Postoperative Hb drop and Hb levels predicted in-hospital mortality.

Type B Aortic Dissections: Current Guidelines for Treatment

Stanford type B aortic dissections (TBADs) involve the descending aorta and can present with complications, including malperfusion syndrome or aortic rupture, which are associated with significant morbidity and mortality if left untreated. Clinical diagnosis is straightforward, typically confirmed using CT angiography. Treatment begins with immediate anti-impulse medical therapy. Acute TBAD with complications should be repaired with emergent thoracic endovascular aortic repair (TEVAR). Uncomplicated TBAD with high-risk features should undergo TEVAR in the subacute phase. Open surgical repair is seldom required and reserved only for select cases. It is critical to follow these patients clinically and radiographically in the outpatient setting.

Promoting False-Lumen Thrombosis after Thoracic Endovascular Aneurysm Repair in Type B Aortic Dissection by Selectively Excluding False-Lumen Distal Entry Tears

PURPOSE

To evaluate the efficacy and clinical outcomes of ancillary endovascular procedures in promoting false-lumen (FL) thrombosis (FLT) and preventing aortic expansion in patients after thoracic endografting for type B dissections.

MATERIALS AND METHODS

This retrospective review included 15 patients (12 men and 3 women; mean age, 59.6 y). Mean aortic diameter at the time of ancillary treatment was 47.4 mm. Different techniques were used as single procedures or sequentially: covered stent occlusion of detached visceral artery entry tears, occlusion of single entry tears with vascular plugs, or aortic endograft occlusion of multiple FL entry tears. FL embolization with ethylene vinyl alcohol copolymer was performed when selective occlusion was considered insufficient to close distal entry tears. Apart from endovascular aneurysm repair, all procedures were performed percutaneously under local anesthesia. If FL diameter increase persisted after 6-month follow-up computed tomographic (CT) angiography, another intervention was planned; otherwise, yearly follow-up was performed.

RESULTS

Mean clinical follow-up duration was 43.8 months (range, 8 d to 86.8 mo), with no in-hospital mortality. Estimated overall survival rates were 93.3%, 86.6%, and 77% at 12, 24, and 48 months, respectively. Three late deaths occurred, one of which was dissection-related at 40 months. Eight surviving patients (53%) had total FLT and 3 had partial FLT with stable aortic diameter on follow-up CT angiography. FL diameter increased in one patient, requiring further intervention.

CONCLUSIONS

Selective exclusion of new distal entry tears remaining after thoracic endovascular aneurysm repair can stabilize abdominal aortic expansion and promote FLT.

Frequency of abdominal aortic expansion after thoracic endovascular repair of type B aortic dissection

Purpose

To determine abdominal aortic expansion after thoracic endovascular aortic repair (TEVAR) in patients with aortic dissection type B and 36 months minimum follow-up.

Methods

Retrospective study of 18 TEVAR patients with follow-up >36 months. Abdominal aortic diameters at celiac trunk (location B) and infrarenal aorta (location C) were recorded on the first and last imaging after TEVAR. False lumen thrombosis was determined at level of endograft (A) and at B and C. Aortic expansion was defined as diameter increase of 5 mm or 15%. Correlation analyses were performed to investigate potential determinants of expansion.

Results

Median follow-up was 75.2 months. Sixteen of 18 patients (88.9%) demonstrated abdominal expansion. Mean expansion was 9.9 ± 6.1 mm at B and 11.7 ± 6.5 mm at C, without a difference between acute and chronic dissections. Critical diameters of 55 mm were reached in two patients treated for chronic dissection (11.1%). Annual diameter increase was significantly greater at locations with baseline diameters >30 mm (2.1 ± 1.1 mm vs. 1.0 ± 0.6 mm, p = 0.009). Baseline diameters were greater in patients with chronic dissections.

Conclusion

Abdominal aortic expansion can be frequently recognized after TEVAR for aortic dissection type B and occurs independently from thoracic false lumen thrombosis. Clinical significant abdominal aortic expansion may occur more frequently in patients treated with TEVAR for chronic dissection.

Standardized Protocol to Analyze Computed Tomography Imaging of Type B Aortic Dissections

Purpose: To propose a standard measuring protocol for type B aortic dissections so as to improve comparability between studies reporting aortic dimensions. Methods: Fifteen computed tomography (CT) scans of type B aortic dissections were measured with a standard protocol by 2 independent observers using postprocessing software. The following parameters were assessed: true, false, and total lumen diameter; true and false lumen volume; and entry tear size, location, and number. Diameters were measured in a perpendicular plane at 2, 10, and 20 cm from the left subclavian artery and 5 cm from the most distal renal artery. True lumen volume was assessed from the left subclavian artery to the aortic bifurcation, while the false lumen volume was from the start to end up to the aortic bifurcation. Entry tear location was assessed in relation to the left subclavian artery. Intra- and interobserver repeatability and agreement were evaluated using the Bland-Altman method, an a priori set of acceptable differences, and Lin’s concordance correlation coefficient (LCCC). Results: Intra- and interobserver mean differences for aortic diameter and true and false lumen volumes were generally within the limits of agreement and the a priori differences; the LCCC showed excellent agreement. Entry tear location, size, and number were difficult to measure in a repeatable manner, with inconsistent correlation coefficients, especially between the 2 observers. Conclusion: This protocol showed acceptable repeatability for aortic diameter and aortic volume measurements. Assessment of entry tears proved challenging and associated with less favorable results. Additionally, investigators are urged to be more transparent regarding the measurement methodology used in studies describing aortic dimensions.

Thoracic Endovascular Repair of Complicated Penetrating Aortic Ulcer

Purpose: To analyze an 11-year single-center experience of treating complicated penetrating aortic ulcer (PAU) using thoracic endovascular aortic repair (TEVAR). Methods: This study included 63 consecutive patients (mean age 69.1±11.5 years; 40 men) with complicated PAU (42 symptomatic, 22 with rupture) who underwent TEVAR between 2002 and 2013. The PAUs were located in the aortic arch (n=11), the descending thoracic aorta (n=43), and the thoracoabdominal aorta (n=9). Results: TEVAR was performed within 14 days of diagnosis in 33 (52.3%) cases (19 ruptures treated immediately); the other 30 (47.6%) patients had an average interval between diagnosis and intervention of 40±39 days. Technical success was 98.4% (62/63). One patient had a type I endoleak after stent-graft repair of a PAU in the aortic arch without great vessel transposition; another procedure was required for carotid-subclavian bypass and proximal stent-graft extension. No patient experienced spinal cord ischemia after TEVAR. Five (7.9%) patients died in-hospital; 3 had severe cardiac complications, 1 died from complications of aortic rupture, and the other succumbed to septic shock. Mean follow-up was 45.6±47.2 months, during which 12 (19.0%) patients needed a secondary intervention because of late endoleaks (n=4, 6.3%) or new complications due to disease progression. Multivariate analysis indicated that a PAU depth >15 mm was an independent predictor of mortality (hazard ratio 6.92, p=0.03). In the biomarker analysis, symptomatic patients had significantly higher D-dimer and troponin levels compared to asymptomatic patients [559.5±460.7 vs 283.2±85.2 µg/L (p=0.016) and 0.22±0.61 vs 0.02±0.03 ng/mL (p=0.04), respectively]. Conclusion: Patients with PAU suffer from underlying severe atherosclerotic disease and have a significant number of cardiovascular comorbidities that lead to relevant mortality and morbidity after TEVAR. As a PAU diameter >15 mm represented high risk for disease progression, these patients may be candidates for early intervention. D-dimer levels may help identify patients at risk and with progression of PAU.

Biomechanical Changes After Thoracic Endovascular Aortic Repair in Type B Dissection

Thoracic endovascular aortic repair (TEVAR) has evolved into an established treatment option for type B aortic dissection (TBAD) since it was first introduced 2 decades ago. Morbidity and mortality have decreased due to the minimally invasive character of TEVAR, with adequate stabilization of the dissection, restoration of true lumen perfusion, and subsequent positive aortic remodeling. However, several studies have reported severe setbacks of this technique. Indeed, little is known about the biomechanical behavior of implanted thoracic stent-grafts and the impact on the vascular system. This study sought to systematically review the performance and behavior of implanted thoracic stent-grafts and related biomechanical aortic changes in TBAD patients in order to update current knowledge and future perspectives.

Prognostic Impact of Blood Pressure Variability on Aortic Dissection Patients After Endovascular Therapy

Hypertension has been deemed as a pivotal risk factor for the development of aortic dissection; however, the importance and prognostic significance of blood pressure variability (BPV) in aortic dissection are always ignored. A total of 173 acute type B aortic dissection patients were enrolled in and retrospectively reviewed between January 2009 and November 2013. There were 74 patients with high BPV and 99 with low BPV stratified by preoperative mean BPV. Technical success was achieved in all patients. The proportions of hypertension and general anesthesia were significantly higher in the high BPV group (70.3% vs 55.6% and 77% vs 62.6%, P = 0.049 and 0.043, respectively). The risk of aorta-related death in the high BPV group was apparently higher than the low BPV group (28.4% vs 9.1%, P = 0.001). By performing multivariable logistic regression, we found history of hypertension was likely to be a risk factor of BPV (95% confidence interval [CI]: 1.010-3.911), and high BPV was an independent predictor of aorta-related death (95% CI: 1.671-9.587). The difference of aorta-related mortality was pronounced between high and low BPV subgroups regardless of the refractory hypertension (41.4% vs 14.3% and 20.0% vs 7.0%, P = 0.023 and 0.037, respectively). The thrombosis ratio of false lumen was significantly higher in the low BPV group at 3-month (72.4 ± 17.5% vs 51.8 ± 11.6%, P < 0.001) and 6-month (86.4 ± 9.1% vs 69.7 ± 7.9%, P < 0.001). High BPV is an independent risk factor for the prognosis of aortic dissection. Further studies on BPV might provide new preventive and therapeutic strategies for aortic dissection.

A systematic review of aortic remodeling after endovascular repair of type B aortic dissection: methods and outcomes

BACKGROUND

Endovascular treatments of Stanford type B aortic dissection may help to promote aortic remodeling and reduce the incidence of aortic-related complications. The aim of this study was to review published literature describing aortic remodeling after endovascular treatment of aortic dissection.

METHODS

A systematic review of the literature was performed which was compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The type of aortic morphology measurements made and the methods used to make them were characterized. The endpoints of interest were the change in these measurements over time.

RESULTS

After initial screening, 77 articles were identified; 16 of which met the inclusion criteria. Few studies used three-dimensional reconstruction software and none had validated their measurement protocol. True lumen (TL) and false lumen (FL) diameters, areas, and in some cases volumes were measured. Studies assessed the aorta at a variety of different levels and over different periods of follow-up. Acute dissection patients displayed more consistent degree of remodeling (thoracic FL thrombosis in 80% to 90%) than chronic dissection patients (38% to 91%). Less remodeling was seen below the diaphragm in both groups.

CONCLUSIONS

Aortic remodeling after treatment for dissection is described in a highly heterogeneous manner. Despite this there appears to be a greater degree of complete FL resolution in patients with acute dissection than chronic. Factors such as length of aortic coverage and timing of treatment may explain the variation seen in the chronic dissection group. Consensus-based reporting standards are required to synthesize evidence and inform clinical decisions regarding patient selection and operative timing.

Volume changes in aortic true and false lumen after the "PETTICOAT" procedure for type B aortic dissection

BACKGROUND

The PETTICOAT (Provisional ExTension to Induce COmplete ATtachment) technique may be employed during endovascular treatment of type B aortic dissection (TBD) using self-expandable bare stents distal to the covered stent graft placed over the proximal entry tear. The aim of this study is to evaluate the volume changes of the true (TL) and false lumen (FL) on computed tomography (CT) scans.

METHODS

Since 2005, 25 selected patients received endovascular treatment for complicated TBD with the PETTICOAT technique employing the Zenith Dissection Endovascular System (William Cook Europe, Bjaerverskov, Denmark). Indications to the use of the PETTICOAT technique were the evidence of clinical manifest dynamic malperfusion in five cases (20%) and/or radiologic evidence of TL collapse in 20 cases (80%). Five patients were treated within 2 weeks from onset, 13 patients between 2 weeks and 3 months, and seven patients over 3 months after the initial acute event. The volumetric analysis of the changes of TL and FL obtained from CT scan performed before endovascular treatment of TBD, postoperatively and yearly thereafter were analyzed using the OsiriX software v 3.9 (Pixmeo sarl, Bernex, Switzerland).

RESULTS

Initial clinical (30 days) and midterm clinical success was observed in 21 cases (84%) and in 23 cases (92%), respectively. The volumes of the aortic TL and FL were evaluated at 30 days and midterm follow-up (mean, 38 ± 17 months). The following TL volumes were recorded: baseline 84 ± 29 cm(3), postoperative 167 ± 31 cm(3) (+98%), 1 year 193 ± 46 cm(3) (+131%), and 2 years 216 ± 54 cm(3) (+140%). The following FL volumes were recorded: baseline 332 ± 86 cm(3), postoperative 286 ± 85 cm(3) (-14%), 1 year 233 ± 81 cm(3) (-30%), and 2 years 248 ± 112 cm(3) (-32%). Progressive remodeling of the TL was recorded over time in both thoracic and abdominal segments with shrinkage of the FL mainly in the thoracic segment.

CONCLUSIONS

These data provide insight into potential therapeutic benefit of the PETTICOAT technique. A significant immediate increase in TL could be achieved with resolution of all cases of dynamic malperfusion and TL collapse. A different behavior of volumes in the thoracic and abdominal segments was observed.