Evolution of aortic dissection after surgical repair

Mechanisms of aortic dissection: From pathological changes to experimental and in silico models

Aortic dissection continues to be responsible for significant morbidity and mortality, although recent advances in medical data assimilation and in experimental and in silico models have improved our understanding of the initiation and progression of the accumulation of blood within the aortic wall. Hence, there remains a pressing necessity for innovative and enhanced models to more accurately characterize the associated pathological changes. Early on, experimental models were employed to uncover mechanisms in aortic dissection, such as hemodynamic changes and alterations in wall microstructure, and to assess the efficacy of medical implants. While experimental models were once the only option available, more recently they are also being used to validate in silico models. Based on an improved understanding of the deteriorated microstructure of the aortic wall, numerous multiscale material models have been proposed in recent decades to study the state of stress in dissected aortas, including the changes associated with damage and failure. Furthermore, when integrated with accessible patient-derived medical data, in silico models prove to be an invaluable tool for identifying correlations between hemodynamics, wall stresses, or thrombus formation in the deteriorated aortic wall. They are also advantageous for model-guided design of medical implants with the aim of evaluating the deployment and migration of implants in patients. Nonetheless, the utility of in silico models depends largely on patient-derived medical data, such as chosen boundary conditions or tissue properties. In this review article, our objective is to provide a thorough summary of medical data elucidating the pathological alterations associated with this disease. Concurrently, we aim to assess experimental models, as well as multiscale material and patient data-informed in silico models, that investigate various aspects of aortic dissection. In conclusion, we present a discourse on future perspectives, encompassing aspects of disease modeling, numerical challenges, and clinical applications, with a particular focus on aortic dissection. The aspiration is to inspire future studies, deepen our comprehension of the disease, and ultimately shape clinical care and treatment decisions.

Comparison of branched, fenestrated, and parallel strategies for endovascular treatment of thoracoabdominal aortic pathologies involving visceral regions

Purpose

To compare the long-term efficacy of the parallel stent graft (PSG), fenestrated stent graft (FSG), and branched stent graft (BSG) techniques to treat thoracoabdominal aortic pathologies.

Materials and methods

In total, 291 patients with thoracic aortic aneurysm (TAA) and dissection (TAD) involving visceral arteries who underwent PSG (n = 85; 15 TAA and 70 TAD), FSG (n = 107; 47 TAD and 60 TAA), or BSG (n = 99; 37 TAD and 62 TAA) were included from multiple centers from January 2015 to December 2022, and a total of 1,108 visceral aortic branches were reconstructed.

Results

The average reconstruction time of each visceral aortic branch for FSG, BSG, and PSG is 27.5 ± 12.1, 23.2 ± 11.9, and 18.8 ± 11.8 min, respectively (P < 0.01). The free-from-endoleak rate at the last follow-up for FSG, BSG, and PSG was 86.9%, 91.9%, and 60.0%, respectively. The last follow-up patency rate for FSG, BSG, and PSG was 85.0%, 91.9%, and 94.1%, respectively. The average reconstruction price of each visceral aortic branch for FSG, BSG, and PSG was 41.40 ± 3.22 thousand RMB, 41.84 ± 3.86 thousand RMB, and 42.35 ± 4.52 thousand RMB, respectively (P = 0.24).

Conclusion

To treat the aortic pathologies involving the visceral segment, BSG had a lower endoleak rate and higher branch patency rate when compared with the FSG and PSG techniques. The expense of BSG was comparable to the other two techniques.

Transient Neurological Deficits in a Patient With Prior DeBakey Type 1 Aortic Dissection

Aortic dissection is a life-threatening emergency that occurs when the aortic wall layers are separated. It is important to recognize that aortic dissections can have an atypical presentation with neurological deficits and not typical findings of chest pain or thoracic symptoms. Our patient presented with headache, vertigo, and transient neurologic deficits. However, imaging revealed no acute stroke. Our patient had a prior history of DeBakey type 1 aortic dissection repaired four years before. Imaging did not demonstrate an acute aortic dissection however there was an increase in size of the aneurysmal components. However, it is unclear if this contributed to the transient neurological deficits. Further research is needed to determine if there is a correlation between aortic aneurysmal enlargement and transient neurological deficits.

Factors Associated with Early Mortality in Acute Type A Aortic Dissection-A Single-Centre Experience

BACKGROUND

Acute aortic dissection type A (AADA) is a surgical emergency with relevant mortality and morbidity despite improvements in current management protocols. Identifying patients at risk of a fatal outcome and controlling the factors associated with mortality remain of paramount importance.

METHODS

In this retrospective observational study, we reviewed the medical records of 117 patients with AADA, who were referred to our centre and operated on between 2005 and 2021. Preoperative, intraoperative, and postoperative variables were analysed and tested for their correlation with in-hospital mortality.

RESULTS

The overall survival rate was 83%. Preoperatively, factors associated with mortality were age (p = 0.02), chronic hypertension (p = 0.02), any grade of aortic valve stenosis in the patient's medical history (p = 0.03), atrial fibrillation (p = 0.04), and oral anticoagulation (p = 0.04). Non-survivors had significantly longer operative times (p = 0.002). During the postoperative phase, mortality was strongly associated with acute kidney injury (AKI) (p < 0.001), acute heart failure (p < 0.001), stroke (p = 0.02), focal neurological deficits (p = 0.02), and sepsis (p = 0.001). In the multivariate regression analysis, the onset of postoperative focal neurological deficits was the best predictor of a fatal outcome after adjusting for ARDS (odds ratio: 5.8, 95%-CI: 1.2-41.7, p = 0.04).

CONCLUSIONS

In this retrospective analysis, atrial fibrillation, oral anticoagulation, hypertension, and age were significantly correlated with mortality. Postoperatively, acute kidney injury, acute heart failure, sepsis, and focal neurological deficits were correlated with in-hospital mortality, and focal neurological deficit has been identified as a significant predictor of fatal outcomes. Early detection and interdisciplinary management of at-risk patients remain crucial throughout the postoperative phase.

Late Post-Dissection Dynamic Intermittent Malperfusion of the Aortic Arch in Association with a Rare Heterogenous LOX Gene Variation

Late ischaemic consequences of type A aortic dissection are rare. We present a 6-year late complication of type A aortic dissection treated by Bentall surgery in a 41-year-old patient. The patient presented with several episodes of lipothymia associated with hypertensive attacks with anisotension, cervicalgia, hemicranial headache, abdominal pain and lower limb slipping initially on exertion and later at rest. On dynamic examination, we diagnosed an intermittent dynamic occlusion of the aortic arch and rare LOX gene variation, which is considered to be associated with aneurysm or dissection of the ascending aorta in young patients. Surgical treatment by replacement of the ascending aorta and the aortic arch with reimplantation of the brachiocephalic trunk (BcTr) allowed the symptoms to resolve.

Can Open Distal Repair Be Safely Used in All Patients with Type A Acute Aortic Dissection?

PURPOSE

The distal suture line during aortic dissection repair can be performed by a closed technique or by an open technique. This study presents a retrospective comparison of both methods regarding their postoperative outcomes.

PATIENTS AND METHODS

120 patients who underwent surgery for acute aortic dissection type A were divided into two groups. In group A (n = 81), open distal anastomosis was performed under hypothermic circulatory arrest and selective cerebral perfusion. In group B (n = 39), distal anastomosis was performed with the aorta cross-clamped under mildly hypothermic cardiopulmonary bypass. Primary outcomes were operative mortality, neurologic morbidity, and long-term survival.

RESULTS

Hospital mortality (17.3% for the open group vs. 12.8% for the closed group, p = 0.53), permanent neurologic dysfunction (8.7% vs. 8.3%, p = 1.0), and temporary neurologic dysfunction (31.9% vs. 22.2%, p = 0.298) were not significantly different between groups. No significant difference in actuarial 5- and 10-year survival was observed (88% vs. 86% and 53 vs. 73%, respectively, p = 0.396). After propensity-score adjustment, the technique of distal aortic repair was not found to be a predictor of the primary outcomes.

CONCLUSION

We conclude that the open repair can be used in most if not all cases of surgical repair of type A acute aortic dissection.

The Fate of Conventional Elephant Trunk in the Frozen Elephant Trunk Era

Conventional elephant trunk (cET) and frozen elephant trunk (FET) are two distinct approaches to the surgical treatment of thoracic aortic aneurysms and dissections. With the advent and growing uptake of endovascular technologies, FET is becoming increasingly popular for its potential to be performed as a single-stage operation with better aortic remodeling and less risk of graft kinking than the traditional two-stage cET procedure. However, FET has been associated with a higher risk of spinal cord ischemia and its use in patients with connective tissue disorder remains controversial. The current review aimed to reflect on recent evidence surrounding the application of cET and FET to different types of aortic pathology in both acute and elective settings. Another scope of this review was to compare the characteristics of the currently available FET commercial devices on the global market. Our findings highlight that when the pathology is confined to the proximal descending aorta, such as in Dsine, intervention is often single-staged and false lumen (FL) thrombosis is achieved with good effect. FET remains limited by spinal cord injury and applicability in patients with connective tissue disorder, although some groups have started to circumvent associated complications, likely due to growing surgical expertise. Many other aortic diseases do require second-stage intervention, and even in these cases, there appears to be lower in-hospital mortality when using FET over cET. This is possibly due to the higher rate of endovascular completion facilitated by the completed landing zones created during FET. FET is trending toward becoming the universal treatment modality for extending repair to the descending aorta.

Implantation of ascyrus medical dissection stent, our first-hand experience

BACKGROUND

Acute type A aortic dissection is associated with high perioperative morbidity and mortality. Ascyrus Medical Dissection Stent (Cryolife, Kennesaw, USA) is a novel uncovered hybrid stent graft developed to be used as an adjunct to standard surgical approach to promote true lumen expansion and enhance aortic remodeling.

METHODS

From March 2021 to March 2022, four consecutive patients presented with acute Debakey type I aortic dissection and underwent emergent surgical repair with Tirone David procedure and implantation of Ascyrus Medical Dissection Stent. We reviewed patient's files retrospectively and described the perioperative outcomes.

RESULTS

All four device implantations were successful. Overall 30-day mortality was 0%. Malperfusion that was present in two patients pre-operatively improved after Ascyrus Medical Dissection Stent implantation. No aortic reinterventions were needed. No aortic injury related to the device was noted. Favourable changes in aortic true lumen and false lumen dimensions were found in most of our patients but the stent was compressed at the isthmus in one patient.

CONCLUSION

Ascyrus Medical Dissection Stent is a reliable and secure device. However, its benefits remain unclear when it comes to a positive remodeling and seems less likelihood comparable to a frozen elephant trunk. The main reason seems to be an insufficient radial force of the stent.

Fate of the Patent False Lumen of the Descending Aorta After Surgical Treatment for Acute Type 1 Aortic Dissection

INTRODUCTION

This study aimed to investigate the factors affecting false lumen patency in the descending thoracic aorta among patients who underwent surgery for acute type 1 aortic dissection.

METHODS

A total of 112 patients with acute type 1 aortic dissection, with the flap below the diaphragm level, underwent surgery between January 2010 and September 2019. Of these, 60 patients who were followed up for ≥ 12 months and whose computed tomography scans were available were included in this study. The patients were divided into two groups: group I, consists of patent false lumen (n=36), and group II, consists of thrombosed false lumen (n=24). Demographic data, operative techniques, postoperative descending aortic diameters, reintervention, and late mortality were compared between the two groups.

RESULTS

The mean follow-up period of all patients was 37.6±26.1 months (range: 12-104). The diameter increase in the proximal and distal descending aorta was significantly higher in the patent false lumen group (5.3±3.7 mm vs. 3.25±2.34 mm; P=0.015; 3.1±2.52 mm vs. 1.9±1.55 mm; P=0.038, respectively). No significant difference in terms of hypertension was found between the two groups during the follow-up period (21 patients, 58.3% vs. 8 patients, 33.3%; P=0.058). A total of 29 patients (48.3%) were found to be hypertensive in the postoperative period.

CONCLUSION

After surgical treatment for acute type 1 aortic dissection, patients should be monitored closely, regardless of whether the false lumen is patent or thrombosed. Mortality and reintervention can be seen in patients with patent false lumen during follow-up.

Advanced risk prediction for aortic dissection patients using imaging-based computational flow analysis

Patients with either a repaired or medically managed aortic dissection have varying degrees of risk of developing late complications. High-risk patients would benefit from earlier intervention to improve their long-term survival. Currently serial imaging is used for risk stratification, which is not always reliable. On the other hand, understanding aortic haemodynamics within a dissection is essential to fully evaluate the disease and predict how it may progress. In recent decades, computational fluid dynamics (CFD) has been extensively applied to simulate complex haemodynamics within aortic diseases, and more recently, four-dimensional (4D)-flow magnetic resonance imaging (MRI) techniques have been developed for in vivo haemodynamic measurement. This paper presents a comprehensive review on the application of image-based CFD simulations and 4D-flow MRI analysis for risk prediction in aortic dissection. The key steps involved in patient-specific CFD analyses are demonstrated. Finally, we propose a workflow incorporating computational modelling for personalised assessment to aid in risk stratification and treatment decision-making.

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.

Initial Surgical Strategy for the Treatment of Type A Acute Aortic Dissection: Does Proximal or Distal Extension of the Aortic Resection Influence the Outcomes?

(1) Background: We sought to analyze and compare the outcomes in terms of early and late mortality and freedom from a redo operation in patients undergoing surgical treatment for a type A acute aortic dissection in relation to the initial surgical treatment strategy, i.e., proximal or distal extension of the aortic segment resection, compared with isolated resection of the supracoronary ascending aorta. (2) Methods: This is a retrospective study in which we included 269 patients who underwent operations for a type A acute aortic dissection in the Department of Cardiac Surgery of Tor Vergata University from May 2006 to May 2016. The patients were grouped according to the extent of the performed surgical treatment: isolated replacement of the supracoronary ascending aorta (NE, no extension), replacement of the aortic root (PE, proximal extension), replacement of the aortic arch (DE, distal extension), and both (BE, bilateral extension). The analyzed variables were in-hospital mortality, postoperative complications (incidence of neurological damage, renal failure and need for prolonged intubation), late mortality and need for a redo operation. (3) Results: Unilateral cerebral perfusion was performed in 49.3% of the patients, and bilateral perfusion—in 50.6%. The overall in-hospital mortality was 31.97%. In the multivariate analysis, advanced age, cardiopulmonary bypass time and preoperative orotracheal intubation were independent predictors of in-hospital mortality. In the population of patients who survived the surgery, the probability of survival at 92 months was 70 ± 5%, the probability of freedom from a redo operation was 71.5 ± 5%, the probability of freedom from the combined end-point death and a redo operation was 50 ± 5%. The re-intervention rate in the general population was 16.9%. The overall probability of freedom from re-intervention was higher in patients undergoing aortic root replacement, although not reaching a level of statistical significance. Patients who underwent aortic arch treatment showed reduced survival. (4) Conclusions: In the treatment of type A acute aortic dissection, all the surgical strategies adopted were associated with satisfactory long-term survival. In the group of patients in which the aortic root had not been replaced, we observed reduced event-free survival.

Fluid-Structure Interaction Simulations of Repaired Type A Aortic Dissection: a Comprehensive Comparison With Rigid Wall Models

This study aimed to evaluate the effect of aortic wall compliance on intraluminal hemodynamics within surgically repaired type A aortic dissection (TAAD). Fully coupled two-way fluid-structure interaction (FSI) simulations were performed on two patient-specific post-surgery TAAD models reconstructed from computed tomography angiography images. Our FSI model incorporated prestress and different material properties for the aorta and graft. Computational results, including velocity, wall shear stress (WSS) and pressure difference between the true and false lumen, were compared between the FSI and rigid wall simulations. It was found that the FSI model predicted lower blood velocities and WSS along the dissected aorta. In particular, the area exposed to low time-averaged WSS ( ≤ 0.2   P a ) was increased from 21 cm2 (rigid) to 38 cm2 (FSI) in patient 1 and from 35 cm2 (rigid) to 144 cm2 (FSI) in patient 2. FSI models also produced more disturbed flow where much larger regions presented with higher turbulence intensity as compared to the rigid wall models. The effect of wall compliance on pressure difference between the true and false lumen was insignificant, with the maximum difference between FSI and rigid models being less than 0.25 mmHg for the two patient-specific models. Comparisons of simulation results for models with different Young's moduli revealed that a more compliant wall resulted in further reduction in velocity and WSS magnitudes because of increased displacements. This study demonstrated the importance of FSI simulation for accurate prediction of low WSS regions in surgically repaired TAAD, but a rigid wall computational fluid dynamics simulation would be sufficient for prediction of luminal pressure difference.

Prediction of aortic dilatation in surgically repaired type A dissection: A longitudinal study using computational fluid dynamics

OBJECTIVE

To examine the role of a key hemodynamic parameter, namely the true and false lumen pressure difference, to predict progressive aortic dilatation following type A aortic dissection (TAAD) repair.

METHODS

Four patients with surgically repaired TAAD with multiple follow-up computed tomography angiography scans (4-5 scans per patient; N = 18) were included. Through-plane diameter of the residual native thoracic aorta was measured in various aortic segments during the follow up period (mean follow-up: 49.6 ± 31.2 months). Computational flow analysis was performed to estimate true and false lumen pressure difference at the same locations and the correlation with aortic size change was studied using a linear mixed effects model.

RESULTS

Greater pressure difference between the true and false lumen was consistent with greater aortic diameter expansion during the follow up period (linear mixed effects analysis; coefficient, 0.26; 95% confidence interval, 0.15-0.37; P < .001). Based on our limited data points, a pressure difference higher than 5 mm Hg might cause unstable aortic growth.

CONCLUSIONS

Computational fluid dynamic assessment of standard aortic computed tomography angiography offers a noninvasive technique that predicts the risk of aortic dilatation following TAAD. The technique may be used to plan closer observation or intervention in high-risk patients.

Imaging and Surveillance of Chronic Aortic Dissection: A Scientific Statement From the American Heart Association

All patients surviving an acute aortic dissection require continued lifelong surveillance of their diseased aorta. Late complications, driven predominantly by chronic false lumen degeneration and aneurysm formation, often require surgical, endovascular, or hybrid interventions to treat or prevent aortic rupture. Imaging plays a central role in the medical decision-making of patients with chronic aortic dissection. Accurate aortic diameter measurements and rigorous, systematic documentation of diameter changes over time with different imaging equipment and modalities pose a range of practical challenges in these complex patients. Currently, no guidelines or recommendations for imaging surveillance in patients with chronic aortic dissection exist. In this document, we present state-of-the-art imaging and measurement techniques for patients with chronic aortic dissection and clarify the need for standardized measurements and reporting for lifelong surveillance. We also examine the emerging role of imaging and computer simulations to predict aortic false lumen degeneration, remodeling, and biomechanical failure from morphological and hemodynamic features. These insights may improve risk stratification, individualize contemporary treatment options, and potentially aid in the conception of novel treatment strategies in the future.

Frozen elephant trunk in acute type A aortic dissections: frontiers and challenges

Acute type A aortic dissection (ATAAD), a surgical emergency, has high mortality and morbidity. More than half of the patients die within 2 weeks and the 30-day mortality is 90%. Frozen elephant trunk in ATAAD addresses the primary and secondary goals - resection of the primary tear in the ascending aorta and promoting remodelling in the downstream aorta. Though the literature supports this fact, in reality these literatures emerge from high-volume centres. But in the "real world" most of the ATAAD are operated on in the low-volume centres. Furthermore, in India, there are unique challenges including the financial burden, transport, emergent availability of the hybrid prosthesis and aortic supercentres.

Numerical modeling of residual type B aortic dissection: longitudinal analysis of favorable and unfavorable evolution

Residual type B aortic dissection was numerically investigated to highlight the contribution of biomechanical parameters to the pathology's evolution. Patient-specific geometries from cases involving both favorable and unfavorable evolution were modeled to assess their hemodynamic features. This original approach was supported by a longitudinal study confirming the association between morphological changes, hemodynamic features, adverse clinical outcomes, and CT-angioscan observations on the same patient. Comparing one patient with unfavorable evolution with one with favorable one, we identify potential biomechanical indicators predictive of unfavorable evolution: (i) a patent false lumen with a flow rate above 50% of inlet flow rate; (ii) high wall shear stress above 18 Pa at entry tears, and above 10 Pa at some regions of the false lumen wall; (iii) low time-averaged wall shear stress in distal false lumen below 0.5 Pa; (iv) vortical structure dynamics. Although these comparisons could only be conducted on 2 patients and need to be confirmed by a larger number of cases, our findings point to these hemodynamic markers as possible candidates for early evaluation of the pathology's evolution towards an unfavorable scenario. Graphical Abstract Correlation between hemodynamics index and thrombus initiation for unfavorable case. ET₂ and ET₃ are entry tear numbers 2 and 3 respectively. WSS is wall shear stress. TAWSS is time average shear stress.

Surveillance Imaging Following Acute Type A Aortic Dissection

BACKGROUND

Survivors of acute type A aortic dissection (ATAAD) repair remain at risk for long-term complications. Guidelines recommend postoperative imaging surveillance, but adherence is uncertain.

OBJECTIVES

The aim of this study was to define the real-world frequency of postoperative imaging and characterize long-term outcomes of ATAAD.

METHODS

Population-based administrative health databases for Ontario, Canada, were linked to identify patients who underwent ATAAD repair and survived at least 90 days. Guideline-directed imaging surveillance (GDIS) was defined as undergoing a computed tomographic or magnetic resonance imaging scan at 6 and 12 months postoperatively and then annually thereafter. Multivariable time-to-event analysis explored the associations between GDIS and all-cause mortality and reintervention.

RESULTS

A total of 888 patients who survived urgent ATAAD repair between April 1, 2005, and March 31, 2018, were included. Median follow-up after ATAAD repair was 5.2 years (interquartile range: 2.4-7.9 years). A total of 14% patients received GDIS throughout follow-up. At 6 years, 3.9% of patients had received GDIS. The mortality rate was 4% at 1 year, 14% at 5 years, and 29% at 10 years. Incidence of aortic reintervention was 3% at 1 year, 9% at 5 years, and 17% at 10 years; the majority of these were urgent (68%), and they carried a 9% 30-day mortality rate. Greater adherence to GDIS was associated with mortality (hazard ratio: 1.08; 95% confidence interval: 1.05-1.11) and reintervention (hazard ratio: 1.04; 95% confidence interval: 1.01-1.07).

CONCLUSIONS

Adherence to GDIS following ATAAD repair is poor, while long-term mortality and reinterventions remain substantial. Further research is needed to determine if guidelines should be modified.

Hybrid Surgical and Endovascular Management of Ascending and Arch Dissection

Historically, a variety of non-dissection proximal aortic pathologies with suitable anatomy have been treated with thoracic endovascular aortic repair (TEVAR) with high technical success rates. However, TEVAR use for acute type A aortic dissection has been extremely limited due to the unique challenging anatomic and clinical features and the lack of specifically-designed endoprostheses. These features include: proximity of the aortic valve, coronary arteries, and supra-aortic vessels, related aortic insufficiency, diffusely dilated aorta diameter, entry tear extension into the aortic root and/or aortic arch, the dissection involvement of supra-aortic vessels, high degrees of ascending aortic curvature and notable length discrepancies between the greater and lesser curvatures, and tissue fragility at prosthesis-tissue transition zones. Additionally, the presence of patent coronary artery bypass grafting conduits on the ascending aorta is another factor precluding endovascular options and hybrid surgical and endovascular approaches may be considered. In contrast, early feasibility clinical trials of investigational devices specifically designed to treat type A aortic dissections have been currently underway. In our opinion, the location and extent of intimal tears are quite variable and only a minority of patients with type A aortic dissection are deemed suitable candidates for ascending TEVAR. On the contrary, combined application of aortic arch endograft, as demonstrated in the present report, likely increases TEVAR candidacy as well as procedural success rates.

Multidimensional Analysis of Descending Aortic Growth After Acute Type A Aortic Dissection

BACKGROUND

After repair of acute type A aortic dissection, typical geometric variables of conventional aortic surveillance focus on maximum diameter and its rate of growth, potentially missing important geometric changes elsewhere. We determined additional information provided by a semiautomated, 3-dimensional (3D), nonlinear growth model of the descending thoracic aorta after repair of type A aortic dissection.

METHODS

Computed tomographic angiography data were retrospectively collected after hemiarch repair of type A aortic dissection. The descending aorta was systematically reconstructed to generate a 3D model made up of individual segments. The baseline and follow-up diameters were measured semiautomatically for each segment, and the nonlinear interval growth was determined.

RESULTS

The fastest growing segment expanded at a rate of 3.8 mm/y (interquartile range, 2.2 to 5.4 mm/y) vs 0.6 mm/y (interquartile range, -0.3 to 1.7 mm/y) when measured at the original site of maximum diameter (P < .01). The maximum baseline diameter was a poor predictor of location with fastest growth (r = 0.10, P > .1). Using the society recommended growth limits, a greater proportion of patients would be considered "at risk" when assessed by our method vs conventional surveillance measures.

CONCLUSIONS

Our model identifies areas of rapid aortic growth after repair of type A dissection that would likely be missed using current surveillance techniques. The increased precision, resolution, and reproducibility provided by our technique may improve on limitations of current surveillance techniques, provide novel geometric data on aortic remodeling, and contribute to the pursuit of a comprehensive patient-specific approach to aortic risk stratification.

Alternatives to the frozen elephant trunk in acute type A aortic dissection

Acute type A aortic dissection remains one of the most challenging condition in cardiothoracic surgery, with a high mortality rate. Various improvements and innovations have happened over the years to better the outcome of this lethal condition. The frozen elephant trunk prosthesis has been developed to negate the long-term complications of acute type A aortic dissection, but at the cost of increased morbidity compared to hemiarch replacement. Although hemiarch and total arch replacement seem have less morbidity than the frozen elephant trunk technique, they do not address the long-term complications of the distal dissected aorta. Few surgeons now suggest hybrid aortic arch repair as a solution for acute type A aortic dissection. The long-term results need to be studied in all procedures before standardizing them. Although multiple strategies are evolving, the short-term goal of acute type A aortic dissection has not changed: to save the patient's life. The surgical strategy has to be tailored according to the patient's condition and the surgeon's experience.

Current status in decision making to treat acute type A dissection: limited versus extended repair

Acute type A aortic dissection remains one of the most challenging conditions in aortic surgery. Despite the advancements in the field, the mortality rate still remains high. Though there is a general consensus that the ascending aorta should be replaced, the distal extension of the surgery still remains a controversy. Few surgeons argue for a conservative approach to reduce operative and postoperative morbidity while others considering the problems associated with "downstream problems" support an aggressive approach including a frozen elephant trunk. The cohort in the Indian subcontinent and APAC is far different from the western world. Many factors determine the decision for surgery apart from the pathology of the disease. Economy, availability of the suitable prosthesis, the experience of the surgeon, ease of access to the medical facility all contribute to the decision making to treat acute type A dissection.

Acute aortic dissection: playing Dhoni 'the finisher' vs Dhoni 'the anchor'

Even in the present era, acute type A aortic dissection (ATAAD) remains one of the most challenging condition in cardiothoracic surgery with a high mortality rate. There have been various surgical techniques and innovations over the years to reduce the mortality and morbidity of these patients. Though there is consensus that the ascending aorta has to be replaced, the controversy still exists on the distal extend of replacing the aorta. Few surgeons opt for a less extensive approach, while others back the extensive frozen elephant trunk. The former defend that extensive surgery has increased morbidity and mortality, while the later argue that multiple entry points are taken care of helping in false lumen thrombosis. But eventually, the short-term goal remains the same - save the patient's life by addressing the tear in the ascending aorta.

Concomitant true and false lumen "parallel thoracic endovascular aortic repair" as an endovascular alternative to open arch/descending aortic reconstruction for chronic DeBakey type I dissection with aneurysmal degeneration

A 77-year-old woman presented with symptomatic thoracic aortic aneurysm within a dissected thoracoabdominal aorta distal to a previous Dacron ascending aortic replacement. She was not a candidate for open repair and had no proximal landing zone for conventional thoracic endovascular aortic repair (TEVAR) resulting from dissection extension into the brachiocephalic vessels. A concomitant parallel graft true and false lumen TEVAR was performed from the distal aortic arch to diaphragm. Follow-up imaging demonstrated successful exclusion of the false lumen aneurysm and successful protection of the true lumen with the adjacent parallel TEVAR device.

Aortic arch replacement with frozen elephant trunk technique - a single-center study

BACKGROUND

The frozen elephant trunk (FET) technique was developed to facilitate the two-stage surgery of extensive pathologies of the thoracic aorta and is now routinely applied in acute and chronic aortic syndromes.

METHODS

From 11/2006 to 07/2017, 68 patients underwent aortic arch repair using the FET technique. Patients received either the Jotec E-vita Open graft (n = 57) or the Vascutek Thoraflex hybrid prosthesis (n = 11). Both, group 1 (acute aortic dissection type A and B; symptomatic penetrating aortic ulcer) and group 2 (aortic aneurysm; chronic aortic dissection) included 34 patients each.

RESULTS

Early mortality was 13.2% (14.7% in group 1 vs. 11.7% in group 2, p = 0.720). Neurological complications occurred in 12 patients (17.6%) (stroke: 8.8 vs. 11.7%; p = 0.797 and spinal cord injury: 8.8 vs. 5.9%; p = 0.642 in groups 1 vs. 2 respectively). Cardiopulmonary bypass time and cross clamp time were significantly longer in group 1 (252.2 ± 73.5 and 148.3 ± 34 min vs. 189.2 ± 47.8 and 116.3 ± 34.5 min; p <  0.001). The overall 1-, 3- and 7-year-survival was 80.9, 80.9 and 74.2% with no significant differences between groups 1 and 2. Expansion of true lumen after FET implantation was significant at all levels in both groups for patients with aortic dissection. One-, 3-, and 7-year-freedom from secondary (re-)intervention for patients for aortic dissection was 96.9, 90.2 and 82.7% with no significant differences between groups 1 and 2; p = 0.575.

CONCLUSION

The FET technique can be applied in acute aortic syndromes with similar risks regarding adverse events or mortality when compared to chronic degenerative aortic disease. Postoperative increase in true lumen diameter mirrors decrease of false lumen diameter, goes along with favorable midterm outcome and prolongs freedom from secondary interventions in acute aortic dissection.

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.

Postoperative care in patients with DeBakey type I aortic dissection: criteria of aortic remodeling and risk factors of disease progression

AIM

To present current treatment modes for DeBakey type I aortic dissection, to compare their early and mid-term postoperative results, to evaluate predictors of negative aortic remodeling after surgery.

MATERIAL AND METHODS

Retrospective cohort analysis included 78 patients with DeBakey type I aortic dissection who underwent surgical treatment in 2009-2017. Patients were divided into 3 groups depending on type of intervention: group I (n=22) - Elephant Trunk procedure, group II (n=29) - hybrid interventions, group III (n=27) - proximal aortic replacement alone. Early postoperative results and aortic remodeling in mid-term postoperative period were compared.

RESULTS

There were no significant differences in postoperative morbidity, in-hospital mortality and freedom from aortic death. However, 7 patients were lost for follow-up in group III. Analysis of false lumen patency showed results in favor of more aggressive approach (groups I and II) with significantly higher rate of false lumen thrombosis in segments 1 and 2 (p<0,001 and p=0,004 respectively). Freedom from negative aortic remodeling was also significantly higher in groups I and II. Risk factors of patent false lumen were residual fenestration, large volume of false lumen in segment 2, dissection of supra-aortic vessels and connective tissue disorders. Risk factors of negative aortic remodeling were connective tissue disorders, patent false lumen and dissection of supra-aortic vessels.

CONCLUSION

Advanced surgical approach (Elephant Trunk procedure or hybrid interventions) should be preferred for DeBakey type I aortic dissection.

Should the distal tears of aortic dissection be treated? The risk of distal tears after proximal repair of aortic dissection

BACKGROUND

Patients with distal residual after proximal repair of aortic dissection (AD) have shown unsatisfactory long-term prognosis. However, possible mechanisms and risk factors for distal aortic segmental enlargement (DSAE) have been poorly understood.

METHODS

We analyzed 962 AD patients repaired to the descending aorta between 1999 and 2014. Aortic morphological characteristics of 419 patients (including 75 DSAE and 344 non-DSAE patients) were investigated and compared. Potential risk factors associated with DSAE were explored using logistic regression analysis or natural logarithmic transformation. Logistic multi regress equations were performed to identify independent risk factors.

RESULTS

Independent risk factors of DSAE are listed as follow: more tears in the thoracic descending aorta (odds ratio [OR], 1.65; 95% confidence interval [CI],1.24 to 2.19; P = .0005); fewer tears in the infra-renal abdominal aorta (OR, 3.00; 95% CI,2.04 to 4.55; P < .0001); closer distance of the first intimal tear to the left subclavian artery (OR, 1.51; 95% CI,1.28 to 1.69; P < .0001); larger average distance between tears (OR, 11.81; 95% CI,3.39 to 41.08; P = .0001); larger maximum distance between two tears (OR, 1.79; 95% CI,1.48 to 2.16; P < .0001), and larger area of remained tears (OR, 1.56; 95% CI, 1.38 to 1.76; P < .0001).

CONCLUSIONS

The location and size of remained tears are the key risk factors of DSAE patients. Long-segment aortic repair and aggressive exclusion of all distal tears located on the thoracic descending aorta in their initial therapy will be an optimal strategy.

Fate of distal aorta after frozen elephant trunk and total arch replacement for type A aortic dissection in Marfan syndrome

OBJECTIVE

The use of the frozen elephant trunk technique for type A aortic dissection in Marfan syndrome is limited by the lack of imaging evidence for long-term aortic remodeling. We seek to evaluate the changes of the distal aorta and late outcomes after frozen elephant trunk and total arch replacement for type A aortic dissection in patients with Marfan syndrome.

METHODS

Between 2003 and 2015, we performed frozen elephant trunk + total arch replacement for 172 patients with Marfan syndrome suffering from type A aortic dissection (94 acute; 78 chronic). Mean age was 34.6 ± 9.3 years, and 121 were male (70.3%). Early mortality was 8.1% (14/172), and follow-up was complete in 98.7% (156/158) at a mean of 6.2 ± 3.3 years. Aortic dilatation was defined as a maximal diameter of greater than 50 mm or an average growth rate of greater than 5 mm/year at any segment detected by computed tomographic angiography. Temporal changes in the false and true lumens and maximal aortic size were analyzed with linear mixed modeling.

RESULTS

After surgery, false lumen obliteration occurred in 86%, 39%, 26%, and 21% at the frozen elephant trunk, unstented descending aorta, diaphragm, and renal artery, respectively. The true lumen expanded significantly over time at all segments (P < .001), whereas the false lumen shrank at the frozen elephant trunk (P < .001) and was stable at distal levels (P > .05). Maximal aortic size was stable at the frozen elephant trunk and renal artery (P > .05), but grew at the descending aorta (P = .001) and diaphragm (P < .001). Respective maximal aortic sizes before discharge were 40.2 mm, 32.1 mm, 31.6 mm, and 26.9 mm, and growth rate was 0.4 mm/year, 2.8 mm/year, 3.6 mm/year, and 2.6 mm/year. By the latest follow-up, distal maximal aortic size was stable in 63.5% (99/156), and complete remodeling down to the mid-descending aorta occurred in 28.8% (45/156). There were 22 late deaths and 23 distal reoperations. Eight-year incidence of death was 15%, reoperation rate was 20%, and event-free survival was 65%. Preoperative distal maximal aortic size (mm) predicted dilatation (hazard ratio, 1.11; P < .001) and reoperation (hazard ratio, 1.07; P < .001). A patent false lumen in the descending aorta predicted dilatation (hazard ratio, 3.88; P < .001), reoperation (hazard ratio, 3.36; P = .014), and late death (hazard ratio, 3.31; P = .045).

CONCLUSIONS

The frozen elephant trunk technique can expand the true lumen across the aorta, decrease or stabilize the false lumen, and stabilize the distal aorta in patients with Marfan syndrome with type A aortic dissection, thereby inducing favorable remodeling in the distal aorta. This study adds long-term clinical and radiologic evidence supporting the use of the frozen elephant trunk technique for type A dissection in Marfan syndrome.

The impact of oral anticoagulation on false lumen patency in acute type A aortic dissections

Background

In this study, the effect of postoperative oral anticoagulation on the false lumen patency of the distal aorta in patients with acute type A aortic dissection was investigated.

Methods

Forty-one patients (32 male, 9 female; mean age 56.8±13.6 years; range, 30 to 84 years) who were diagnosed with acute type A aortic dissection and underwent surgical treatment in our clinic, and whose entire data of both control computed tomographic assessments and all postoperative follow-up visits could be accessed were enrolled. The patients were divided into two groups according to the type of surgical intervention that was performed. Computed tomography imaging of the patients were scanned and false lumen patency rates were evaluated. Besides oral anticoagulation, preoperative, intraoperative, and postoperative risk factors that may have affected false lumen patency secondary to acute type A aortic dissection were evaluated and statistically analyzed.

Results

Twenty-one patients (51.2%) had concomitant hypertension. Thirty five (85.4%) of the patients had the main symptom of angina. Sixteen patients (39%) in Group 1 underwent ascending aortic replacement combined with aortic valve replacement (Bentall procedure); while 25 patients (61%) in Group 2 underwent isolated ascending aortic replacement. Mean follow-up was 43.9±26.3 (range: 5-120) months. No statistically significant difference was found between the study subgroups in any of the operation parameters except for cardiopulmonary bypass time (p=0.035) and cross-clamp time (p=0.002). Evaluation of the control contrast-enhanced tomographic imaging of the patients showed false lumen patency in the thorax in 34 patients (82.9%) and in the abdominal region in 33 patients (80.5%). When analyzing subgroups according to the type of surgical procedure, or indirectly anticoagulant use, no statistically significant difference was found in false lumen patency prevalence between the thoracic and abdominal groups (p=0.534 and p=0.922).

Conclusion

No potential effect of postoperative anticoagulation on false lumen patency was found in cases with acute type A aortic dissection.

Techniques and outcomes of secondary open repair for chronic dissection after acute repair of type A aortic dissection

Despite successful repair of acute type A aortic dissection (TAAD), the distal false lumen may remain patent resulting in progressive degeneration of the remaining distal aorta. This can lead to aneurysmal dilatation and risk of rupture. Open distal reoperation to replace the residually dissected thoraco-abdominal aorta may be accomplished with acceptable morbidity and mortality in experienced hands. This can be facilitated when the index operation for acute TAAD is tailored to exclude all primary tears and set the arch and descending aorta for a subsequent open, endovascular or hybrid procedure.

Acute type A aortic dissection: Rationale and outcomes of extensive repair of the arch and distal aorta

Type A acute aortic dissection represents one of the most complex and life-threatening disorders of the cardiovascular system. Cardiac tamponade caused by ascending aorta rupture is the most common cause of death. In light of this, emergent surgery with ascending and partial arch replacement represents, in most of cases, the best and the faster therapeutic option. The natural history of aortic dissection, however, teaches us that in most cases there is a distal progression of the aortic disease that often requires further surgical and/or endovascular treatments. In light of this, it can be hypothesized that, by increasing the extent of aortic replacement during the first operation, it may improve the outcome of these patients by reducing the probability of a second surgery or, in selected cases and for appropriate indications, by treating with a single surgical step, the disease. In this short review of the literature, we focalized on the rationale and outcome of an extensive repair of the thoracic aorta.

Remnant aortic remodelling in younger patients after acute type I aortic dissection surgery

OBJECTIVES

To study the influence of age on remnant aortic remodelling after acute DeBakey type I aortic dissection (AD) surgery.

METHODS

Between January 1999 and December 2013, 118 acute type I AD patients (26 aged <50 years, Group A; 92 aged  ≥ 50 years, Group B) with either ascending or ascending hemiarch replacement in whom preoperative and >1-month postoperative chest computed tomography (CT) were available were included.

RESULTS

At median CT follow-up of 35.1 (interquartile range, 14.1-65.2) months, the aortic dimensions in Group A increased significantly from the baseline values at the root, arch and descending thoracic aorta levels at 40.8 ± 5.3 mm to 43.1 ± 6.5 mm ( P  = 0.010), 36.8 ± 7.1 mm to 40.7 ± 8.8 mm ( P  = 0.043) and 36.7 ± 6.8 mm to 42.8 ± 11.4 mm ( P  = 0.009), respectively. In Group B, only the descending thoracic aorta had increased significantly from the baseline at 37.8 ± 4.8 mm to 40.7 ± 9.4 mm ( P  = 0.002). Linear regression analysis showed a significant correlation between younger age and aortic size increase, especially at the aortic sinus level. No significant between-group differences in mortality and reoperation rates were seen during the follow-up of 45.0 ± 33.6 months vs 44.1 ± 31.7 months, respectively.

CONCLUSIONS

A significantly greater tendency for the remnant aorta to undergo more rapid and generalized adverse remodelling was seen in younger patients after acute type I AD surgery.

Total arch replacement and frozen elephant trunk for type A aortic dissection after Bentall procedure in Marfan syndrome

Background

We seek to report the long-term outcomes of the total arch replacement and frozen elephant trunk (TAR + FET) technique for type A aortic dissection (TAAD) following prior Bentall procedure in patients with Marfan syndrome (MFS).

Methods

Between 2003 and 2015, we performed TAR + FET for 26 patients with MFS who developed TAAD following a prior Bentall procedure. Mean age at FET 36.9±9.7 years and 24 were males. TAAD was acute in 8 (30.8%, all new dissections from precious root aneurysm) and chronic in 18 (69.2%, 15 residual and 3 new). The interval from Bentall procedure to FET averaged 6.4±5.8 years, which was significantly longer in the acute group (10.3±6.3 vs. 4.6±4.9, P=0.021). The early and long-term outcomes were compared between two groups and risk factors identified for late adverse events.

Results

Operative mortality was 11.5% (3/26). Stroke, lower limb ischemia and reexploration for bleeding occurred in 1 patient each (3.8%). Follow-up was complete in 100% (23/23) at mean 5.1±2.3 years (range, 0.9-11.2 years). The maximal diameter (DMax) of distal aorta in the chronic group was significantly greater at the unstented descending aorta [DA, (56.4±15.5 vs. 35.6±12.2 mm, P=0.006)] compared to acute patients. The false lumen was obliterated in 95.7% across the FET and 56.5% in the unstented DA. Distal aortic dilation occurred in 13 patients (11 chronic, 68.8%). Of those 11 patients, 4 underwent an open thoracoabdominal aortic repair and 3 died of distal aortic rupture. Late death occurred in 7 patients at mean 3.9±2.5 years. At 6 years, the incidence was 18% for death, 11% for distal aortic reoperation, and 71% for reoperation-free survival. Survival did not differ between two groups (75.0% vs. 71.3%, P=0.851), while acute patients had significantly higher freedom from late rupture and reoperation at 6 years (100% vs. 61.9%, P=0.046). Hypertension was the sole risk factor for distal aortic dilatation [hazard ratio (HR) =7.271; 95% confidence interval (CI), 1.814-29.143; P=0.005]. Risk factors for late adverse events were hypertension (HR =6.712; 95% CI, 1.201-37.503; P=0.030) and age <35 years (HR =6.760; 95% CI, 1.154-39.587; P=0.034).

Conclusions

The TAR and FET technique was feasible and efficacious for TAAD following previous Bentall procedure in patients with MFS. Early and late survival did not differ with acute and chronic dissections, while freedom from late rupture and reoperation is significantly higher in patients with acute TAAD. Patients with hypertension and aged <35 years are at higher risk for late distal aortic dilation, reoperation and death.

Thoracic Endovascular Aortic Repair for Aortoesophageal Fistula after Covered Rupture of Aortic Homograft: A Durable Option?

A 63-year-old woman underwent replacement of the aortic root, ascending aorta, and partial arch due to Type A aortic dissection. Shortly thereafter, a replacement of the distal aortic arch and descending aorta was performed. Three years later, the patient developed an aortoesophageal fistula (AEF) resulting in re-replacement of the distal aortic arch and proximal descending aorta with a cryopreserved aortic homograft. Six weeks post-discharge, the patient was readmitted due to recurrent AEF. A thoracic endovascular stent graft was implanted to cover the aortic rupture, followed by correction of an esophageal lesion. The patient was monitored closely over time.

Aortic Remodeling Following Sun's Procedure for Acute Type A Aortic Dissection

Background

Sun’s procedure is a surgical technique widely used in type A aortic dissection. The purpose of this study was to analyze clinical outcomes and morphologic changes in true and false lumen by computed tomography (CT) angiography after Sun’s procedure.

Material/Methods

We retrospectively reviewed 51 patients who underwent Sun’s procedure for acute Stanford type A aortic dissection extending down to iliac bifurcation between January 2013 and December 2014. The images of preoperative, one-month, three-month, and six-month follow-up were analyzed by CT angiography to measure the area and diameter of true and false lumen.

Results

Four patients died before surgical intervention and postoperative deaths occurred in five patients (in-hospital mortality rate 10.6%). Only 42 patients (36 male, 6 female; mean age, 45.9±9.8 years; range, 24–65 years) with acute type A aortic dissection were involved in our study. Thirty-five patients (83.3%) suffered from chest or abdominal pain and only one patient (2.4%) was asymptomatic. Thirty-seven patients (88.1%) had hypertension as the most common comorbidity. In the ascending aorta, false lumen was eliminated and the change of true lumen was not significant (p>0.05). In the descending aorta, complete and partial thrombosis of false lumen were observed in eight patients (19.0%) and 33 patients (78.6%) by one-month follow-up CT scan, respectively. After the six-month follow-up, the rate of complete thrombosis increased to 36.1% and partial thrombosis decreased to 61.9%. The area and maximal diameter of true lumen were increased significantly (p<0.05), whereas significant decreases were found in the area and maximal diameter of false lumen (p<0.05). In the abdominal aorta, thrombosis was found in 52.4% patients at one-month follow-up CT. Furthermore, there were no significant changes in both true and false lumen within three months (p>0.05). Nevertheless, the false luminal area and maximal diameter decreased significantly (p<0.05) after six months, while these changes of true lumen were not significant (p>0.05).

Conclusions

After Sun’s procedure, aortic remodeling was a continuous process and occurred in a predictable model, and the extent of aortic remodeling varied at different levels. Remodeling in descending thoracic aorta was earlier than it was in abdominal aorta.

Total Arch versus Hemiarch Replacement for Type A Acute Aortic Dissection: A Single-Center Experience

We retrospectively evaluated early and intermediate outcomes of aortic arch surgery in patients with type A acute aortic dissection (AAD), investigating the effect of arch surgery extension on postoperative results. From January 2006 through July 2013, 201 patients with type A AAD underwent urgent corrective surgery at our institution. Of the 92 patients chosen for this study, 59 underwent hemiarch replacement (hemiarch group), and 33 underwent total arch replacement (total arch group) in conjunction with ascending aorta replacement. The operative mortality rate was 22%. Total arch replacement was associated with a 33% risk of operative death, versus 15% for hemiarch (P=0.044). Multivariable analysis found these independent predictors of operative death: age (odds ratio [OR]=1.13/yr; 95% confidence interval [CI], 1.04-1.23; P=0.002), body mass index >30 kg/m² (OR=9.9; 95% CI, 1.28-19; P=0.028), postoperative low cardiac output (OR=10.6; 95% CI, 1.18-25; P=0.035), and total arch replacement (OR=8.8; 95% CI, 1.39-15; P=0.021) The mean overall 5-year survival rate was 59.3% ± 5.5%, and mean 5-year freedom from distal reintervention was 95.4% ± 3.2% (P=NS). In type A AAD, aortic arch surgery is still associated with high operative mortality rates; hemiarch replacement can be performed more safely than total arch replacement. Rates of distal aortic reoperation were not different between the 2 surgical strategies.

When and how to replace the aortic arch for type A dissection

Acute type A aortic dissection (AAAD) remains one of the most challenging diseases in cardiothoracic surgery and despite numerous innovations in medical and surgical management, early mortality remains high. The standard treatment of AAAD requires emergency surgery of the proximal aorta, preventing rupture and consequent cardiac tamponade. Resection of the primary intimal tear and repair of the aortic root and aortic valve are well-established surgical principles. However, the dissection in the aortic arch and descending untreated aorta remains. This injury is associated with the risk of subsequent false lumen dilatation potentially progressing to rupture, true lumen compression and distal malperfusion. Additionally, the dilatation of the aortic arch, the presence of a tear and retrograde dissection can all be considered indication for a total arch replacement in AAAD. In such cases a more aggressive strategy may be used, from the classic aortic arch operation to a single stage frozen elephant trunk (FET) technique or a two-stage approach such as the classical elephant trunk (ET) or the recent Lupiae technique. Although these are all feasible solutions, they are also complex and time demanding techniques requiring experience and expertise, with an in the length of cardiopulmonary bypass and both myocardial and visceral ischemia. Effective methods of cerebral, myocardial as well visceral protection are necessary to obtain acceptable results in terms of hospital mortality and morbidity. Moreover, a correct assessment of the anatomy of the dissection, through the preoperative angio CT scan, in addition to the clinical condition of the patients, remain the decision points for the best arch repair strategy to use in AAAD.

Total aortic repair: the new paradigm in the treatment of acute type A aortic dissection

The surgical management of acute type A aortic dissection (ATAAD) is in a period of rapid evolution. Understanding the complex physiology and anatomy of both acute and chronic dissection has been enhanced by the ready availability of state of the art imaging techniques. Technical advances in the intraoperative monitoring of organ perfusion, together with adjuncts to limit organ injury and increasing sophistication in open and endovascular surgery have led to a major reduction in both perioperative morbidity and mortality. In many centers, there has been a transition in mindset and surgical approach away from a purely central aortic operation focusing on the ascending aorta and a 'live to fight another day' philosophy. The current more global perspective recognizes the importance of aortic valve function, malperfusion, false lumen (FL) patency and the potential for future complex aneurysm development. The time is now right to transition into the next phase of sophistication in the management of ATAAD with the aim of achieving not only a safe acute operation, but to either entirely prevent chronic complications or to greatly simplify their management by the creation of an anatomical situation that facilitates future endovascular intervention in place of complex re-do surgery. We present our view on the evolution of surgery for ATAAD leading to our current technique of Branch First Arch replacement and Total Aortic Repair, which not only provides a safe immediate operation, but also offers the hope of a simplified future management if not a total cure for the pathology.