What makes the difference between the natural course of a remaining type B dissection after type A repair and a primary type B aortic dissection?

Long-term results of the frozen elephant trunk technique in primary chronic type B aortic dissection

OBJECTIVES

The aim of this study is to analyze long-term results of the total aortic arch replacement with the frozen elephant trunk technique for primary chronic type B aortic dissection.

METHODS

Among 322 patients who had the frozen elephant trunk technique, 43 (13.4%) patients (median age, 64.0 years) with primary chronic type B aortic dissection were analyzed. The patients underwent surgery at a median of 27.0 months after the onset of aortic dissection. The false lumen was patent in 30 (69.8%) patients preoperatively.

RESULTS

Two patients suffered paraplegia and another died of cerebral infarction. Complete thrombosis of the peri-stent false lumen was achieved in 36 (83.7%) patients. Overall survival, freedom from aortic events, and freedom from aortic reintervention were 83.5%, 37.2%, and 42.2% at 5 years, respectively. Survival rates of the patients with or without aortic events were 75.0% and 95.8% at 5 years (Log-rank, p = 0.22). Late aortic events occurred in 19 (44.2%) patients including distal stent graft-induced new entry, type Ib endoleak, and false lumen dilation. The ratio of the stent graft diameter to the preoperative short axis diameter of the true lumen (hazard ratio, 1.90; 95% confidence interval, 1.01-3.59), and the maximal diameter of a postdissection aneurysm (1.07; 1.01-1.12) were the significant multivariate risk predictors of late aortic events.

CONCLUSIONS

Late aortic events occurr fairly frequently, and new strategies need to be explored to enhance the effectiveness of this procedure in the future.

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.

[Choice of optimal treatment policy in patients with descending aortic dissection]

Contemporary approaches to treatment of patients with dissection of the descending aorta (DA), as well as the data of international registries and guidelines are contradictory. The endovascular method of treatment of patients with descending aortic dissection has been recognized to be revolutionary. However, there seems to be no commonly accepted concept concerning appropriate use of currently available techniques of treating patients with DA dissection. This study was aimed at analysing the experience gained in using various methods of treatment of patients with descending aortic dissection (DAD). We retrospectively examined the results of surgical treatment of 78 patients with DAD. Of these, 45 patients were found to have Stanford type B dissection and 33 patients had type A dissection, who underwent treatment during ten years from January 2008. The decision concerning the type of care for patients with DAD (conservative, surgical, endovascular or combined methods of treatment) directly depends on the patient's state stability, technical feasibility of the intended procedure, and the presence of concomitant pathology. The findings obtained in our study demonstrated better immediate outcomes of the endovascular approach compared with the hybrid and surgical ones. In order to achieve complete haemodynamic correction of the pathology, to minimize the risk of aortic remodelling and the development of aorta-related complications, the treatment should not be limited to endoprosthetic repair of the thoracic portion of the DA with a stent graft, but should rather be supplemented with stenting of more distal segments, including with uncoated stents at the level of the visceral branches. Only such staged approach may provide better conditions for obliteration of the aortic false lumen and formation of a 'neo-frame' of the aortic wall.

Current evidence in predictors of aortic growth and events in acute type B aortic dissection

OBJECTIVES

Acute type B aortic dissection can have a stable course or evolve into aneurysm and subsequent adverse events. The aim of this systematic review was to analyze the morphologic predictors of an adverse course to establish their validity based on consistency of results.

METHODS

Fifty-one studies were included in this review, reporting on aortic size, false lumen (FL) size, primary entry tear (ET) size and location, status of FL thrombosis, number of ETs, branch vessels involvement, and FL longitudinal extent.

RESULTS

Some predictors showed good consistency, whereas others did not. Aortic size was the most investigated predictor. A larger diameter at presentation predicted worse outcomes, with few exceptions. Both FL size and size relative to true lumen size also predicted an adverse course, although a standardized measurement method was not used. Regarding primary ET size and location, evidence was sparse and somewhat conflicting. Although FL complete thrombosis was consistently associated with a more benign course, the role of partial thrombosis remained unclear and the concept of FL saccular formation might account for the inconsistency, but further evidence is needed. A higher number of re-entry tears was considered to be protective against false channel expansion, but results need to be confirmed. The predictive role of branch vessels involvement and FL longitudinal extent remain controversial.

CONCLUSIONS

Among several predictors of aortic growth and events in acute type B aortic dissection, controversial and even conflicting results have been described. Consistent evidence has been demonstrated only for two predictors: aortic size at presentation is associated with adverse events and total FL thrombosis has a protective role.

Frozen elephant trunk and arch endografts for chronic thoracoabdominal aortic dissections

Chronic aortic dissecting aneurysms (TAAD) presenting after acute Stanford type A or B dissection includes both arch and/or thoracoabdominal aortic aneurysms (TAAA). Approximately 60% of patients who survive surgical treatment of acute type A aortic dissections will require another aortic procedure. Similarly, more than 70% of patients with chronic type B aortic dissections will experience false lumen dilation at 5-year follow-up, often requiring intervention. Open or hybrid aortic repairs of complex TAAD involving the arch and the TAAA are very demanding procedures for both patients and clinicians. Open surgery remains the first line therapy in fit patients. Recent development of branched arch devices has offered an alternative option for high-risk patients. Technical challenges associated with the endovascular management of these complex aneurysms include proximal sealing zone often located in the aortic arch or the ascending aorta, narrow true lumen working space, and aortic branch perfusion by either the true or false lumen, or both. Recent studies have reported encouraging results with endovascular treatment of these complex dissecting aneurysms, especially following open ascending aortic repair. The aim of this review was to describe the available strategies for arch repair in the setting of a chronic TAAD and to determine the subset of patients that can benefit from of a totally endovascular approach.

Chronic type B "residual" after type A: what I would do?

"The major goal of surgery for acute type A aortic dissection is to have an alive patient." This motto still remains the most important directive. However, also depending onto the extent of the underlying pathology and consecutively depending onto the extent of primary surgery, there is and will be need for additional classical surgical or interventional treatment sooner or later during follow-up in a substantial number of patients having had surgery for acute type A aortic dissection. This article shall guide the interested reader through the underlying mechanisms as well as treatment options in patients with chronic type B "residual" after type A repair and shall finally suggest preventive strategies to reduce the occurrence of this pathology to a minimum.

Multi-Velocity Encoding Four-Dimensional Flow Magnetic Resonance Imaging in the Assessment of Chronic Aortic Dissection

Background: Chronic descending thoracic aortic dissection (CDTAD) following surgical repair of ascending aortic dissection requires long-term imaging surveillance. We investigated four-dimensional (4D)-flow magnetic resonance imaging (MRI) with a novel multi-velocity encoding (multi-VENC) technique as an emerging clinical method enabling the dynamic quantification of blood volume and velocity throughout the cardiac cycle.

Methods: Patients with CDTAD (n = 10; mean age, 55.1 years; standard deviation (SD) 10.8) and healthy volunteers (n = 9; mean age, 37.1 years; SD 11.4; p < 0.01) underwent 3T MRI, and standard views and 4D-flow data were obtained. Flow measurements were made in selected regions of interest within the ascending and descending thoracic aorta.

Results: The overall flow profile at peak systole was reduced in the false lumen (FL) compared with the true lumen (TL) and normal aortas (p < 0.05 for velocity < 0.4 m/s). Peak systolic flow rate per aortic lumen area (mL/s/cm ² ) was lower in the FL than in the TL (p < 0.05), and both rates were lower than that of control aortas (p < 0.05). Blood flow reversal was higher in the FL than in the TL throughout the descending aorta in CDTAD patients (p < 0.05). A derived pulsatility index was elevated in the TL compared with that in the FL in CDTAD patients. Generated pathline images demonstrated flow patterns in detail, including sites of communication between the true and FL.

Conclusions: 4D-flow MRI revealed FL blood flow and reduced blood flow velocity and flow rate in the TL of CDTAD patients compared with normal aortas of healthy participants. Thus, multi-VENC 4D-flow MRI could serve as an adjunct in the long-term assessment of CDTAD following surgical repair of ascending aortic dissection.

Prediction of Intimal Tear Site by Computed Tomography in Acute Aortic Dissection Type A

Background and Objectives

Preoperative identification of intimal tear site in acute type A dissection will help procedural planning. The objective of this study was to determine the key findings of computed tomography (CT)-based prediction for tear site and compare the accuracy between radiologists and surgeons.

Subjects and Methods

Multi-detector CT (MDCT) images from 50 patients who underwent surgical repair of type A aortic dissection were retrospectively reviewed by 4 cardiac surgeons with limited experience or by 3 radiologists specialized in cardiovascular imaging. Surgical findings of intimal tear site were used as references.

Results

In surgical findings, the locations of intimal tear that were identified in 43 patients included aorta (n=25), ascending with arch (n=7), and arch only (n=11). The rest were retrograde dissections from the tear of descending aorta. Key CT findings that were most frequently found were defect in the intimal flap shadow (30.0±4.0 patients/reviewer, accuracy 87.0±11.7%) and differential filling of false lumen by phase and location (9.4±2.9 patients/reviewer, 84.8±10.4%). Surgeons predicted tear site (75.0±7.7% vs. 86.7±1.2%, p=0.055) and specified flap defect (80.5±10.3% vs. 95.7±7.4%, p=0.073) with lower accuracy than radiologists.

Conclusions

With MDCT imaging, well-educated surgeons could be accurate in three fourths of cases. There was room for improvement through experience. Considering the substantial possibility of inaccuracy, critical decisions on CT images should be made through thorough reviewing by as many experienced radiologists and surgeons as possible.

Hybrid repair of type A acute aortic dissections with the Lupiae technique: ten-year results

OBJECTIVES

Replacing the ascending aorta and the arch in patients with type A acute aortic dissection achieves good short-term results, but several patients are left with distal intimal tears or a patent false lumen in the descending aorta. In this series, we report the 10-year experience with the Lupiae technique, a hybrid aortic repair technique for patients with type A acute aortic dissection.

METHODS

From 2003 to 2013, 89 patients with type A acute aortic dissections underwent replacement of the ascending aorta, the arch, and the rerouting of the neck vessels on the ascending aorta, creating a proximal Dacron landing zone for a completion with thoracic endovascular aortic repair if necessary.

RESULTS

In-hospital mortality was 8.9%. In 16 patients, the false lumen healed spontaneously, whereas the remaining 65 patients underwent thoracic endovascular aortic repair. One patient died after thoracic endovascular aortic repair. Eighty patients were followed up. Complete thrombosis of the false lumen was obtained in 93.8% of patients. The median follow-up was 46 ± 35 months. Overall 8-year survival was 93.7% ± 5%, 100% for patients with spontaneously healed residual false lumen after just type A acute aortic dissection repair and 92.3% ± 7.7% for patients who underwent thoracic endovascular aortic repair after type A acute aortic dissection repair. In 10 years, 1 patient underwent a reoperation on the distal aorta (1.25%).

CONCLUSIONS

The availability of a Dacron landing zone on the distal ascending aorta after type A acute aortic dissection repair allows the exclusion, with a thoracic endovascular aortic repair, of any residual intimal tear refilling a patent false lumen. This approach seems to be associated with a high probability of false lumen thrombosis and low rates of reoperations on the distal aorta.

Endovascular repair of acute uncomplicated aortic type B dissection promotes aortic remodelling: 1 year results of the ADSORB trial

OBJECTIVES

Uncomplicated acute type B aortic dissection (AD) treated conservatively has a 10% 30-day mortality and up to 25% need intervention within 4 years. In complicated AD, stent grafts have been encouraging. The aim of the present prospective randomised trial was to compare best medical treatment (BMT) with BMT and Gore TAG stent graft in patients with uncomplicated AD. The primary endpoint was a combination of incomplete/no false lumen thrombosis, aortic dilatation, or aortic rupture at 1 year.

METHODS

The AD history had to be less than 14 days, and exclusion criteria were rupture, impending rupture, malperfusion. Of the 61 patients randomised, 80% were DeBakey type IIIB.

RESULTS

Thirty-one patients were randomised to the BMT group and 30 to the BMT+TAG group. Mean age was 63 years for both groups. The left subclavian artery was completely covered in 47% and in part in 17% of the cases. During the first 30 days, no deaths occurred in either group, but there were three crossovers from the BMT to the BMT+TAG group, all due to progression of disease within 1 week. There were two withdrawals from the BMT+TAG group. At the 1-year follow up there had been another two failures in the BMT group: one malperfusion and one aneurysm formation (p = .056 for all). One death occurred in the BMT+TAG group. For the overall endpoint BMT+TAG was significantly different from BMT only (p < .001). Incomplete false lumen thrombosis, was found in 13 (43%) of the TAG+BMT group and 30 (97%) of the BMT group (p < .001). The false lumen reduced in size in the BMT+TAG group (p < .001) whereas in the BMT group it increased. The true lumen increased in the BMT+TAG (p < .001) whereas in the BMT group it remained unchanged. The overall transverse diameter was the same at the beginning and after 1 year in the BMT group (42.1 mm), but in the BMT+TAG it decreased (38.8 mm; p = .062).

CONCLUSIONS

Uncomplicated AD can be safely treated with the Gore TAG device. Remodelling with thrombosis of the false lumen and reduction of its diameter is induced by the stent graft, but long term results are needed.

Double arterial perfusion strategy for extensive thoracic aortic surgery to avoid lower body hypothermic circulatory arrest

OBJECTIVE

To analyse our results of using a double arterial perfusion strategy to avoid lower body hypothermic circulatory arrest after extensive thoracic aortic surgery.

METHODS

We analysed the intra- and perioperative courses of 10 patients (median age 58 years, median logistic EuroSCORE 14.6) who underwent extensive thoracic aortic surgery with a double arterial perfusion strategy. The main goal of double arterial perfusion is to separate myocardial and supra-aortic from systemic perfusion. Aortic repair starts at the most distal level of the descending aorta, followed by reinsertion of the supra-aortic vessels, and ends with completion of the proximal anastomosis or by any kind of root repair as needed.

RESULTS

Seven of 10 patients had prior surgery of the thoracic aorta. Indications for surgery were post-dissection aneurysm in 4 patients, true aneurysm in 3, anastomotic aneurysms in 2 and Type B aortic dissection with pseudo-coarctation in 1. Surgical access was performed through median sternotomy with left hemi-clamshell extension in all cases. There was no in-hospital mortality, but perioperative neurological symptoms occurred in 2 patients. These 2 patients developed delayed stroke (after awaking) after an initial uneventful clinical course, and in 1 of them, neurological symptoms resolved completely during follow-up. The median follow-up was 7 (± 13) months. There was no death and no need for additional redo surgery during this observational period.

CONCLUSIONS

Extensive surgery of the thoracic aorta using a double arterial perfusion technique in order to avoid lower body hypothermic circulatory arrest is an attractive option. Further refinements of this technique may enable the safe and effective simultaneous multisegmental treatment of thoracic aortic pathology in patients who would otherwise have to undergo a two-step surgical approach.

Extent of preoperative false lumen thrombosis does not influence long-term survival in patients with acute type A aortic dissection

Background

Partial thrombosis of the false lumen has been related to aortic growth, reoperations, and death in the chronic phase of type B and repaired type A aortic dissections. The impact of preoperative false lumen thrombosis has not been studied previously. We used data from a contemporary, multinational database on aortic dissections to evaluate whether different degrees of preoperative false lumen thrombosis influenced long‐term prognosis.

Methods and Results

We examined the records of 522 patients with surgically treated acute type A aortic dissections who survived to discharge between 1996 and 2011. At the preoperative imaging, 414 (79.3%) patients had patent false lumens, 84 (16.1%) had partial thrombosis of the false lumen, and 24 (4.6%) had complete thrombosis of the false lumen. The annual median (interquartile range) aortic growth rates were 0.5 (−0.3 to 2.0) mm in the aortic arch, 2.0 (0.2 to 4.0) mm in the descending thoracic aorta, and similar regardless of the degree of false lumen thrombosis. The overall 5‐year survival rate was 84.7%, and it was not influenced by false lumen thrombosis (P=0.86 by the log‐rank test). Independent predictors of long‐term mortality were age >70 years (hazard ratio [HR], 2.34; 95% confidence interval [CI], 1.20 to 4.56, P=0.012) and postoperative cerebrovascular accident, coma, and/or renal failure (HR, 2.62; 95% CI, 1.40 to 4.92, P=0.003).

Conclusions

Patients with acute type A aortic dissection who survive to discharge have a favorable prognosis. Preoperative false lumen thrombosis does not influence long‐term mortality, reintervention rates, or aortic growth.

Total surgical aortic arch replacement as a safe strategy to treat complex multisegmental proximal thoracic aortic pathology

OBJECTIVE

To analyse the results after elective open total aortic arch replacement.

METHODS

We analysed 39 patients (median age 63 years, median logistic EuroSCORE 18.4) who underwent elective open total arch replacement between 2005 and 2012.

RESULTS

In-hospital mortality was 5.1% (n = 2) and perioperative neurological injury was 12.8% (n = 5). The indication for surgery was degenerative aneurysmal disease in 59% (n = 23) and late aneurysmal formation following previous surgery of type A aortic dissection in 35.9% (n = 14); 5.1% (n = 2) were due to anastomotical aneurysms after prior ascending repair. Fifty-nine percent (n = 23) of the patients had already undergone previous proximal thoracic aortic surgery. In 30.8% (n = 12) of them, a conventional elephant trunk was added to total arch replacement, in 28.2% (n = 11), root replacement was additionally performed. Median hypothermic circulatory arrest time was 42 min (21-54 min). Selective antegrade cerebral perfusion was used in 95% (n = 37) of patients. Median follow-up was 11 months [interquartile range (IQR) 1-20 months]. There was no late death and no need for reoperation during this period.

CONCLUSIONS

Open total aortic arch replacement shows very satisfying results. The number of patients undergoing total arch replacement as a redo procedure and as a part of a complex multisegmental aortic pathology is high. Future strategies will have to emphasize neurological protection in extensive simultaneous replacement of the aortic arch and adjacent segments.

Long-term results after proximal thoracic aortic redo surgery

OBJECTIVE

To evaluate early and mid-term results in patients undergoing proximal thoracic aortic redo surgery.

METHODS

We analyzed 60 patients (median age 60 years, median logistic EuroSCORE 40) who underwent proximal thoracic aortic redo surgery between January 2005 and April 2012. Outcome and risk factors were analyzed.

RESULTS

In hospital mortality was 13%, perioperative neurologic injury was 7%. Fifty percent of patients underwent redo surgery in an urgent or emergency setting. In 65%, partial or total arch replacement with or without conventional or frozen elephant trunk extension was performed. The preoperative logistic EuroSCORE I confirmed to be a reliable predictor of adverse outcome- (ROC 0.786, 95%CI 0.64-0.93) as did the new EuroSCORE II model: ROC 0.882 95%CI 0.78-0.98. Extensive individual logistic EuroSCORE I levels more than 67 showed an OR of 7.01, 95%CI 1.43-34.27. A EuroSCORE II larger than 28 showed an OR of 4.44 (95%CI 1.4-14.06). Multivariate logistic regression analysis identified a critical preoperative state (OR 7.96, 95%CI 1.51-38.79) but not advanced age (OR 2.46, 95%CI 0.48-12.66) as the strongest independent predictor of in-hospital mortality. Median follow-up was 23 months (1-52 months). One year and five year actuarial survival rates were 83% and 69% respectively. Freedom from reoperation during follow-up was 100%.

CONCLUSIONS

Despite a substantial early attrition rate in patients presenting with a critical preoperative state, proximal thoracic aortic redo surgery provides excellent early and mid-term results. Higher EuroSCORE I and II levels and a critical preoperative state but not advanced age are independent predictors of in-hospital mortality. As a consequence, age alone should no longer be regarded as a contraindication for surgical treatment in this particular group of patients.