What is the appropriate size criterion for resection of thoracic aortic aneurysms?

Ascending Aortic Diameter after Dissection Does Not Reflect Size before Dissection

Introduction

Current guidelines for prophylactic resection of ascending aortic aneurysms are based on post-dissection aortic diameter. However, this may not reflect the diameter prior to dissection.

Report

Pre- and post-dissection aortic diameters were compared in 34 patients with available computerised tomography scans. The median time interval between these scans was 536 days (interquartile range 354 – 1237).

Discussion

There was a statistically significant difference in diameters from the sinotubular junction to the proximal abdominal aorta, the largest was in the ascending aorta with a mean of 7.6 mm (standard deviation 4.5). This suggests that the ascending aortic diameter is a poor predictor of dissection in most patients.

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Ascending aortic diameter expands due to acute dissection.

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Post-dissection aortic diameters probably overestimate pre-dissection diameters.

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Following ascending dissection, diameter expansion is not limited to aorta ascendens.

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In this sample, estimated pre-dissection ascending aortic diameters were below 60 mm in 91% of patients and below 50 mm in 85%.

Increased Virulence of Descending Thoracic and Thoracoabdominal Aortic Aneurysms in Women

BACKGROUND

This study evaluates sex differences in the natural history of descending thoracic and thoracoabdominal aortic aneurysms (DTTAAs).

METHODS

In all, 907 patients with descending thoracic and thoracoabdominal aortic sizes greater than 3 cm were retrospectively reviewed. Growth rate estimates were performed utilizing an instrumental variables approach. Yearly complication rates as a function of aortic size were computed.

RESULTS

There were 615 men (67.8%) and 292 women (32.2%) treated between 1990 and 2018, with mean aortic diameters of 4.1 ± 1.4 cm and 4.8 ± 1.6 cm, respectively (P < .001). The mean growth rate of DTTAAs was 0.17 cm per year in men and 0.25 cm per year in women (P < .001), increasing with increasing aneurysm size. Dissection, rupture, or aortic death or the combination of the three occurred at double the rate for women compared with men (5.8% vs 2.3% per year for the combined endpoint). Diameter of DTTAA greater than 5 cm was associated with 26.3% (male) and 33.1% (female) average yearly rates of the composite endpoint of rupture, dissection, and death (P < .05). The probability of fatal complications (rupture and death) increased sharply at 5.75 cm in both sexes. Between 4.5 and 5.75 cm, there was another hinge-point of higher probability of fatal complications among women.

CONCLUSIONS

Women diagnosed with DTTAA fare worse. Faster aneurysm growth and higher rates of dissection, rupture, and aortic death are apparent among women. Current guidelines recommend surgical intervention at 5.5 to 6 cm for DTTAAs without sex considerations. Our findings suggest that increased virulence of DTTAA in women may indicate surgery at a somewhat smaller diameter.

Are dilated ascending aortas of Chinese patients more likely to dissect?

Background

Ascending aortic aneurysm is a disease requiring surgical intervention. However, the timing of operation is still controversial. The purpose of this study is to compare the ascending aortic diameter and postoperative outcomes in hospital between patients with simple ascending aortic dissection and patients with simple ascending aortic dilation in China, and to investigate the accuracy of the timing of operation determined by ascending aortic diameter alone.

Methods

We reviewed the data from 2,520 hospitalized patients of aortic aneurysm and aortic dissection who underwent surgical treatment from January 2010 to June 2017 in our hospital. A total of 139 simple ascending aortic dissection and simple ascending aortic aneurysm hospitalized patients excluding Marfan syndrome and heart valve diseases etc. (56 in the aortic dilatation group and 83 in the aortic dissection group) were enrolled. The t-test and univariable analysis were used to compare the differences between two groups.

Results

For the aortic diameter, the group of aneurysm has greater ascending aortic diameter and the index of ascending aortic diameter compared with the group of dissection (P<0.001, P<0.001). For male patients, the result is the same (P<0.001, P<0.001). But for female patients, there was no significant statistical significance between the two groups (P=0.631, P=0.288). For the postoperative outcomes, the dissection group had higher mortality, incidence of tracheotomy and postoperative re-exploration for hemorrhage (P=0.040, P=0.011, P=0.028).

Conclusions

The majority of patients with simple ascending aortic dissection present with aortic diameters <5.5 cm and this is not consistent with the current operation indications of aortic aneurysm. It is far from enough to predict aortic dissection with aortic diameter alone. More indicators are needed to do this.

Patient-Specific CT-Based Fluid-Structure-Interaction Aorta Model to Quantify Mechanical Conditions for the Investigation of Ascending Aortic Dilation in TOF Patients

Background

Some adult patients with Tetralogy of Fallot (TOF) were found to simultaneously develop ascending aortic dilation. Severe aortic dilation would lead to several aortic diseases, including aortic aneurysm and dissection, which seriously affect patients' living quality and even cause patients' death. Current practice guidelines of aortic-dilation-related diseases mainly focus on aortic diameter, which has been found not always a good indicator. Therefore, it may be clinically useful to identify some other factors that can potentially better predict aortic response to dilation.

Methods

20 TOF patients scheduled for TOF repair surgery were recruited in this study and were divided into dilated and nondilated groups according to the Z scores of ascending aorta diameters. Patient-specific aortic CT images, pressure, and flow rates were used in the construction of computational biomechanical models.

Results

Simulation results demonstrated a good coincidence between numerical mean flow rate at inlet and the one obtained from color Doppler ultrasonography, which implied that computational models were able to simulate the movement of the aorta and blood inside accurately. Our results indicated that aortic stress can effectively differentiate patients of the dilated group from the ones of the nondilated group. Mean ascending aortic stress-P1 (maximal principal stress) from the dilated group was 54% higher than that from the nondilated group (97.97 kPa vs. 63.47 kPa, p value = 0.044) under systolic pressure. Velocity magnitude in the aorta and aortic wall displacement of the dilated group were also greater than those of the nondilated group with p value < 0.1.

Conclusion

Computational modeling and ascending aortic biomechanical factors may be used as a potential tool to identify and analyze aortic response to dilation. Large-scale clinical studies are needed to validate these preliminary findings.

Primary Lymphoma Presenting in an Ascending Aortic Aneurysm: A Case Report

Small lymphocytic lymphoma (SLL) is rarely associated with thoracic aortic aneurysms. Aneurysm of the ascending aorta associated with SLL has never been reported before. We describe the case of an asymptomatic 68-year-old woman who presented with a 5.5-cm aneurysm of the ascending aorta and no prior history of hematological disorders. Following excision and repair, the surgical specimen showed infiltration of the aortic wall by lymphocytes, expressing markers consistent with SLL. While symptomatic SLL carries a poor prognosis, risk stratification tools are applied to guide management strategies in asymptomatic patients.

The science of BAV aortopathy

The aortopathy associated with bicuspid aortic valve (BAV) is an epidemiologically relevant source of chronic and acute aortic disease (aneurysm and dissection). However, its pathogenesis is still the object of scientific uncertainties and debates. Indeed, the mechanisms determining the diseases of the ascending aorta in BAV patients are most likely complex and multifactorial, i.e. resulting from variable modes of interplay between genetic and hemodynamic factors. Although few scientific studies have so far taken into adequate account this complexity, leaving the precise sequence of pathogenetic events still undiscovered, the accumulated evidence from previous research approaches have at least brought about important insights. While genetic studies have so far identified variants relevant to either valve malformation or aortic complications (including those in the genes NOTCH1, TGFBR2, ACTA2, GATA5, NKX2.5, SMAD6, ROBO4), however each explaining not more than 5% of the study population, other investigations have thoroughly described both the flow features, with consequent forces acting on the arterial wall (including skewed flow jet direction, rotational flow, wall shear stress), and the main changes in the molecular and cellular wall structure (including extracellular matrix degradation, smooth muscle cell changes, oxidative stress, unbalance of TGF-β signaling, aberrant endothelial-to-mesenchymal transition). All of this evidence, together with the recognition of the diverse phenotypes that the aortopathy can assume in BAV patients, holding possible prognostic significance, is reviewed in this chapter. The complex and multifaceted body of knowledge resulting from clinical and basic science studies on BAV aortopathy has the potential to importantly influence modes of clinical management of this disease in the near future.

Ruptured Aortic Aneurysm and Dissection Related Death: an Autopsy Database Analysis

Acute aortic catastrophes (AAC), mainly ruptured aneurysms and dissections, lead all other vascular conditions in morbidity and mortality, even if intervention occurs. The aim of our study was to give a descriptive overview of the demographic and pathological characteristics of AAC. Between 1994 and 2013, 80,469 autopsies were performed at Semmelweis University hospitals in Budapest. After collecting the autopsy reports we were able to create the AAC database upon which we conducted our analysis. We found 567 cases of AAC. The cause of death in 120 of them was classified as a non-ruptured aorta with malperfusion or distal embolization. Of the remaining 447 cases, in 305 the cause of death was a ruptured aortic aneurysm (rAA), and in 142 it was a ruptured aortic dissection (rAD). The distribution of rAA cases was 34.4% thoracal, 4.3% thoracoabdominal, and 61.3% abdominal. We found female dominance where the rAA was thoracal. In rAD cases, 84% were Stanford A and 16% Stanford B type. In both groups we found different pathological distributions. In the prehospital group, the number of thoracal ruptures was considerable. 88% of the patients with Stanford A dissection died in the prehospital or perioperative period. The most progressive AACs were ruptures of intrapericardial aneurysms and Stanford A dissections., however survival rate can be elevated by using rapid imaging examination and immediate surgical intervention. We want to highlight that our study contains such gender differences, which are worth to be taken into consideration.

Correlation of intracranial and aortic aneurysms: current trends and evidence

The correlation between intracranial and aortic aneurysms remains elusive. Data in the literature are scattered, and outcome reporting is swamped with heterogeneity and single-center bias. This calamity is adding to confusion on decision-making and delays the instigation of appropriate clinical applications. This literature review delves into the abyss of the lack of clinically driven scientific input, and highlights the trends explored thus far.

Current Status of Endoluminal Treatment of Descending Thoracic Aortic Aneurysms

Thoracic endovascular aortic repair (TEVAR) was proved to be effective in thoracic descending aortic aneurysm (TDAA) repair in 1994 and approved by the FDA in 2005. Since then, TEVAR has become the first-line, recommended treatment for intact or ruptured DTAA or as a bridge to definitive open surgical repair in connective tissue disease. TEVAR has decreased perioperative morbidity and mortality compared to open surgery due to the lack of thoracotomy, aortic cross-clamping and left heart bypass. Improvement in materials, manufacturing and device delivery systems have allowed for the expansion of indications. Thoughtful and accurate pre-procedure planning is the hallmark of successful TEVAR. Familiarization and adherence to the instructions for use for an aortic device will give the best possible chance of success.

Statistical Shape Analysis of Ascending Thoracic Aortic Aneurysm: Correlation between Shape and Biomechanical Descriptors

An ascending thoracic aortic aneurysm (ATAA) is a heterogeneous disease showing different patterns of aortic dilatation and valve morphologies, each with distinct clinical course. This study aimed to explore the aortic morphology and the associations between shape and function in a population of ATAA, while further assessing novel risk models of aortic surgery not based on aortic size. Shape variability of n = 106 patients with ATAA and different valve morphologies (i.e., bicuspid versus tricuspid aortic valve) was estimated by statistical shape analysis (SSA) to compute a mean aortic shape and its deformation. Once the computational atlas was built, principal component analysis (PCA) allowed to reduce the complex ATAA anatomy to a few shape modes, which were correlated to shear stress and aortic strain, as determined by computational analysis. Findings demonstrated that shape modes are associated to specific morphological features of aneurysmal aorta as the vessel tortuosity and local bulging of the ATAA. A predictive model, built with principal shape modes of the ATAA wall, achieved better performance in stratifying surgically operated ATAAs versus monitored ATAAs, with respect to a baseline model using the maximum aortic diameter. Using current imaging resources, this study demonstrated the potential of SSA to investigate the association between shape and function in ATAAs, with the goal of developing a personalized approach for the treatment of the severity of aneurysmal aorta.

Impact of histopathological changes in ascending aortic diseases

AIMS

To better understand relationship between histological medial degenerative changes (MDC), pathological status [thoracic aorta aneurysm (TAA), thoracic aorta dissection (TAD), bicuspid aortic valve (BAV), and non-BAV] and aortic size at imaging.

METHODS AND RESULTS

We collected 496 ascending aorta surgical specimens from patients with degenerative aortic diseases (mean age, 61 years) whose imaging data were available, including BAV in 191 (TAD 4%, TAA 96%) and with non-BAV in 305 (TAD 45%, TAA 55%). We analyzed them according to the pathology consensus statement and scored MDC [elastic fiber fragmentation and/or loss (EFFL); smooth muscle nuclei loss (SMNL); mucoid extracellular matrix accumulation (MEMA), intralamellar (I) or translamellar (T)] and measured medial wall thickness on correlation with imaging data and the status (TAA, TAD, BAV, or non-BAV). In TAA subset, EFFL, SMNL and MEMA-T scores were lower in BAV than in non-BAV. In relation to the aortic diameter, EFFL, SMNL and MEMA-T scores were more important in TAD subset than in TAA at the small aortic diameters. Independent predictors of aortic dissection included thicker medial wall (odds ratio [OR], 6.3; 95% confidence interval [CI], 2.4 to 17.6; p < 0.0001) and greater SMNL score (OR, 1.2; 95% CI, 1.1 to 1.3; p = 0.003).

CONCLUSIONS

This large cohort study confirms that non-BAV aortas present higher MDC scores than BAV aortas. Higher MDC scores are correlated with increased aortic diameter. TAD can occur not infrequently in smaller aortas associated with high MDC scores. This suggests that risk stratification of aortic dissection based on aorta dimensions is imperfect.

Evaluating the diagnostic accuracy of maximal aortic diameter, length and volume for prediction of aortic dissection

OBJECTIVE

Management of thoracic aortic aneurysms (TAAs) comprises regular diameter follow-up until the indication criterion for prophylactic surgery is reached. However, this approach is unable to predict the majority of acute type A aortic dissections (ATAADs). The current study aims to evaluate the diagnostic accuracy of ascending aortic diameter, length and volume for occurrence of ATAAD.

METHODS

This two-centre observational cohort study retrospectively screened 477 consecutive patients who presented with ATAAD between 2009 and 2018. Of those, 25 (5.2%) underwent CT angiography (CTA) within 2 years before dissection onset. Aortic diameter, length and volume of these patients ('pre-ATAAD') were compared with those of TAA controls (n=75). Receiver operating curve analysis was performed to evaluate the predictive accuracy of the three different measurements.

RESULTS

96% of patients with pre-ATAAD did not meet the surgical diameter threshold of 55 mm before dissection onset. Maximal aortic diameters (45 (40-49) mm vs 46 (44-49) mm, p=0.075) and volume (126 (95-157) cm³ vs 124 (102-136) cm³, p=0.909) were comparable between patients with pre-ATAAD and TAA controls. Conversely, ascending aortic length (84±9 mm vs 90±16 mm, p=0.031) was significantly larger in patients with pre-ATAAD. All three parameters had an area under the curve of >0.800. At the 55 mm cut-off point, the maximal diameter yielded a positive predictive value (PPV) of 20%. While maintaining same specificity levels, measurements of aortic volume and length showed superior diagnostic accuracy (PPV 55% and 70%, respectively).

CONCLUSION

Measurements of aortic volume and length have superior diagnostic accuracy compared with the maximal diameter and could improve the timely identification of patients at risk for ATAAD.

The impact of age on patients undergoing aortic arch surgery: Evidence from a multicenter national registry

OBJECTIVE

Elderly patients are typically offered aortic surgery at similar diameter thresholds as younger patients, despite limited data quantifying their operative risk. We aim to report the incremental risk experienced by elderly patients undergoing aortic arch surgery.

METHODS

In total, 2520 patients underwent aortic arch surgery between 2002 and 2018 in 10 centers. Patients were divided into 3 groups: <65 years (n = 1325), 65 to 74 years (n = 737), and ≥75 years (n = 458). Outcomes of interest were in-hospital mortality, stroke, and the modified Society of Thoracic Surgeons composite for mortality or major morbidity (STS-COMP). Multivariable modeling was performed to determine the association of age with these outcomes.

RESULTS

As age increased, there was an increasing rate of comorbidities, including diabetes (P < .001), renal failure (P < .001), and previous stroke (P = .01). Rates of acute aortic syndrome (P = .50) and total arch repair were similar (P = .59) between groups. Older patients had greater mortality (<65: 6.1% vs 65-74: 9.0% vs ≥75: 14%, P < .001), stroke (6.3% vs 7.7% vs 11%, P = .01) and STS-COMP (25% vs 32% vs 38%, P < .001). After multivariable risk-adjustment, a step-wise increase in complications was observed in the older age groups relative to the youngest in terms of in-hospital mortality (65-74: odds ratio [OR] 1.57, P = .04; ≥75: OR, 2.94, P = .001) and STS-COMP (65-74: OR, 1.57, P < .001; ≥75: OR, 1.96, P < .001).

CONCLUSIONS

Older patients experienced elevated rates of mortality and morbidity following aortic arch surgery. These results support a more measured approach when evaluating elderly patients. Further research is needed on age-dependent natural history of thoracic aneurysms and size thresholds for intervention.

Giant unruptured sinus of Valsalva aneurysm successfully managed with valve-sparing procedure - a case report

Background

Sinus of Valsalva aneurysm (SVA) is an uncommon cardiac anomaly, with an incidence of less than 1% of open heart surgery cases. Its evolution is most frequently silent, being found incidentally or discovered in the event of its acute rupture. Non-ruptured giant SVAs may cause unusual clinical manifestations, as a consequence of their protrusion into the heart chambers or compression of the coronary vessels and are frequently associated with aortic insufficiency of various degrees of severity. The gold standard treatment for SVAs consists of complete replacement of the aortic root and valve. However, in certain cases, valve-sparing procedures may prove to be a more suitable alternative.

Case presentation

A 68-year-old male patient presented with dyspnea as symptom caused by a large (> 5 cm) right sinus of Valsalva aneurysm. The aneurysm was occupying most of the right ventricle and was associated with severe aortic regurgitation. The surgical treatment of the condition involved valve-sparing root reconstruction procedure (remodeling technique), completed with external stabilization of the aortic valve annulus via running suture annuloplasty. Following the uneventful intervention, the patient did well and his status improved. The follow-up transthoracic echocardiography obtained 1 month after surgery showed a fully competent aortic valve with no regurgitation.

Conclusions

Despite complete aortic root and valve replacement being considered the safest approach to large SVAs complicated with aortic insufficiency, valve-sparing procedures should not be overlooked in case of a dilated aortic root with uncalcified aortic valve. Performing valve-sparing by applying a remodeling technique operation completed with annuloplasty reduces aortic valve insufficiency, avoiding side-effects related to implanted valves.

Natural history of descending thoracic and thoracoabdominal aortic aneurysms

OBJECTIVES

Elucidating critical aortic diameters at which natural complications (rupture, dissection, and death) occur is of paramount importance to guide timely surgical intervention. Natural history knowledge for descending thoracic and thoracoabdominal aortic aneurysms is sparse. Our small early studies recommended repairing descending thoracic and thoracoabdominal aortic aneurysms before a critical diameter of 7.0 cm. We focus exclusively on a large number of descending thoracic and thoracoabdominal aortic aneurysms followed over time, enabling a more detailed analysis with greater granularity across aortic sizes.

METHODS

Aortic diameters and long-term complications of 907 patients with descending thoracic and thoracoabdominal aortic aneurysms were reviewed. Growth rates (instrumental variables approach), yearly complication rates, 5-year event-free survival (Kaplan-Meier), and risk of complications as a function of aortic height index (aortic diameter [centimeters]/height [meters]) (competing-risks regression) were calculated.

RESULTS

Estimated mean growth rate of descending thoracic and thoracoabdominal aortic aneurysms was 0.19 cm/year, increasing with increasing aortic size. Median size at acute type B dissection was 4.1 cm. Some 80% of dissections occurred below 5 cm, whereas 93% of ruptures occurred above 5 cm. Descending thoracic and thoracoabdominal aortic aneurysm diameter 6 cm or greater was associated with a 19% yearly rate of rupture, dissection, or death. Five-year complication-free survival progressively decreased with increasing aortic height index. Hazard of complications showed a 6-fold increase at an aortic height index of 4.2 or greater compared with an aortic height index of 3.0 to 3.5 (P < .05). The probability of fatal complications (aortic rupture or death) increased sharply at 2 hinge points: 6.0 and 6.5 cm.

CONCLUSIONS

Acute type B dissections occur frequently at small aortic sizes; thus, prophylactic size-based surgery may not afford a means for dissection protection. However, fatal complications increase dramatically at 6.0 cm, suggesting that preemptive intervention before that criterion can save lives.

Selective and marked decrease of complement receptor C5aR2 in human thoracic aortic aneurysms: a dysregulation with potential inflammatory effects

Objective

The aetiology of thoracic aortic aneurysm (TAA) is largely unknown, but inflammation is likely to play a central role in the pathogenesis. In this present study, we aim to investigate the complement receptors in TAA.

Methods

Aortic tissue and blood from 31 patients with non-syndromic TAA undergoing thoracic aortic repair surgery were collected. Aortic tissue and blood from 36 patients with atherosclerosis undergoing coronary artery bypass surgery or aortic valve replacement were collected and served as control material. The expression of the complement anaphylatoxin receptors C3aR1, C5aR1 and C5aR2 in aortic tissue were examined by quantitative RT-PCR and C5aR2 protein by immunohistochemistry. Colocalisation of C5aR2 to different cell types was analysed by immunofluorescence. Complement activation products C3bc and sC5b-9 were measured in plasma.

Results

Compared with controls, TAA patients had substantial (73%) downregulated gene expression of C5aR2 as seen both at the mRNA (p=0.005) level and protein (p=0.03) level. In contrast, there were no differences in the expression of C3aR1 and C5aR1 between the two groups. Immunofluorescence examination showed that C5aR2 was colocalised to macrophages and T cells in the aortic media. There were no differences in the degree of systemic complement activation between the two groups.

Conclusion

Our findings suggest downregulation of the C5aR2, regarded to act mainly anti-inflammatory, in electively operated TAA as compared with non-aneurysmatic aortas of patients with aortic stenosis and/or coronary artery disease. This may tip the balance towards a relative increase in the inflammatory responses induced by C5aR1 and thus enhance the inflammatory processes in TAA.

Sex-Specific Outcome after Ascending Aortic Surgery in Moderate Hypothermic Circulatory Arrest

BACKGROUND

Historically, female patients had worse outcome undergoing heart surgery. No recent data exist on gender-specific outcome after moderate hypothermic circulatory arrest (MHCA). The aim of this large retrospective analysis was to investigate gender disparity in patients undergoing elective surgery of ascending aorta in MHCA at 24°C.

METHODS

We conducted a retrospective review of 905 (33.3% female) cases of elective heart surgery in MHCA for ascending aortic aneurysm (90.9%) or severely calcified aorta (12.5%) between 2001 and 2015. Furthermore, 299 female and 299 male patients matched by propensity score were compared. Patients with dissection of the aorta were excluded.

RESULTS

Women were older (68.4 ± 9.9 vs. 65.8 ± 11.6 years; p = 0.002), had higher logistic EuroSCORE I (18.4 [11.7; 29.2] vs. 12.3% [7.4; 22.6]; p < 0.001), and significantly shorter cardiopulmonary bypass (CPB) time (132 [105; 175] vs. 150 [118; 192] minutes; p < 0.001), while mean MHCA time was longer (15 [13; 19] vs. 14 [12; 17] minutes; p = 0.003). Surgical procedures were less complex in women and they were treated more frequently by isolated supracoronary ascending aorta replacement (61 vs. 54%; p = 0.046). Postoperatively, men showed a higher incidence of neurologic complications (7.0 vs. 3.3%; p = 0.03). The 30-day mortality (women 4.9% vs. men 3.9%; p = 0.48) did not differ significantly, likewise after statistical matching (4.7 vs. 2.3%; p = 0.120). Age, CPB time, and blood transfusion, but not female gender, were risk factors for mortality in multivariable regression analysis.

CONCLUSION

This study supports the hypothesis that female gender is not associated with increased short-term mortality or perioperative adverse events in elective aortic surgery in MHCA.

Functional Magnetic Resonance Imaging in the Evaluation of the Elastic Properties of Ascending Aortic Aneurysm

Objective

To evaluate the aortic wall elasticity using the maximal rate of systolic distension (MRSD) and maximal rate of diastolic recoil (MRDR) and their correlation with the aortic size index (ASI).

Methods

Forty-eight patients with thoracic aortic aneurysm were enrolled in this study. A standard magnetic resonance imaging (MRI) protocol was used to calculate MRSD and MRDR. Both MRSD and MRDR were expressed as percentile of maximal area/10^-3 sec. ASI (maximal aortic diameter/body surface area) was calculated. A correlation between MRSD, MRDR, ASI, and the patient’s age was performed using regression plot.

Results

A significant correlation between MRSD (t=-4,36; r²=0.29; P≤0.0001), MRDR (t=3.92; r²=0.25; P=0.0003), and ASI (25±4.33 mm/m²; range 15,48-35,14 mm/m²) is observed. As ASI increases, aortic MRSD and MRDR decrease. Such inverse correlation between MRSD, MRDR, and ASI indicates increased stiffness of the ascending aorta. A significant correlation between the patient’s age and the decrease in MRSD and MRDR is observed.

Conclusion

MRSD and MRDR are significantly correlated with ASI and the patient’s age. They seem to describe properly the increasing stiffness of aortas. These two new indexes provide a promising, accessible, and reproducible approach to evaluate the biomechanical property of the aorta.

Midterm prognosis of type B aortic dissection with and without dissecting aneurysm of descending thoracic aorta after endovascular repair

Few studies support guidelines for the use of thoracic endovascular aortic repair (TEVAR) to address type B aortic dissection (TBAD) coexisting with descending thoracic aortic dissection and aneurysm (dTADA). This cohort study investigated midterm outcomes of TBAD with dTADA (dTADA group, n = 31) and without dTADA (non-dTADA group, n = 98) after TEVAR. Compared with the non-dTADA group, the dTADA group exhibited higher incidences of type Ia endoleak (29.0% vs. 3.1%, P < 0.001) and reintervention (16.1% vs. 5.1%, P = 0.045). The completely thrombosed rate of the thoracic false lumen was significantly lower in the dTADA group than in the non-dTADA group (45.2% vs. 80.6%, P < 0.001). Although the two groups exhibited similar mortality rates, TBAD coexisting with no regressive dTADA after TEVAR was an independent predictor of mortality (HR: 15.52, 95% CI: 1.614-149.233, P = 0.018). Moreover, the change percentages of false lumen retraction and true lumen re-expansion in the dTADA group were significantly inferior to those of the non-dTADA group at levels of 4th, 6th, 8th and 10th thoracic vertebra throughout follow-up. In conclusion, in the presence of preexisting dTADA, the failure of the dTADA to regress after TEVAR is associated with lower survival and a higher risk of reintervention.

Size and dissection: what is the relation?

Thoracic aortic aneurysm is a complex disease. The consequences of such silent and indolent disease include acute aortic syndrome if not recognized early and treated appropriately. Aortic aneurysm size was a reliable clinical marker to aid clinical intervention; however, aneurysm growth is variable and is influenced by many factors such as age, presence of connective tissue disorders, genetic disorders, hypertension, inflammatory conditions of the aorta, autoimmune diseases, smoking, and history of previous cardiac surgery. Therefore, aortic size became a non-specific disease surrogate and prediction tool on outcome and intervention. In this review article, we examined the current literature for evidence about aneurysm size and its relation to type A aortic dissection.

Threshold for intervention upon ascending aortic aneurysms: an evolving target and implication of bicuspid aortic valve

With the proliferation of non-invasive thoracic imaging modalities, the question of when to operate on asymptomatic ascending aortic aneurysms for non-syndromic patients is becoming increasingly relevant. Operation is extensive, often involves circulatory arrest, and subjects the patient to significant risk of mortality and morbidity. Surgery is performed to avert fatal aortic adverse events, which carry a markedly poor prognosis. The question of when the balance is tipped toward preemptive surgical repair is challenging and is centered around predicting the risk of an acute aortic syndrome. Size of the aneurysm has been the traditional guide for decision-making but how this is measured, what risks it truly predicts, the influence of the patient's size, valve morphology, genetic profile, and other risk factors for non-syndromic patients are poorly understood. We here review this issue in detail.

An economic analysis of medical and surgical management of aortopathy associated with bicuspid aortic valve

Aims

To develop a cost-effectiveness model to address the outcome and economic implications of different thresholds for surgery in the management of aortopathy associated with bicuspid aortic valve disease.

Methods and results

A model was created from the perspective of an Australian healthcare funding agency. The index case was a 65-year-old with bicuspid aortic valve (BAV) and ascending aorta diameter of 5.0 cm. Health states were defined as: pre-operative with dilated aorta, post-operative without complications, post-complication, and death. The mean and variance of risks and transition probabilities were taken from a local surgical database and local costs and utilities of elective and urgent thoracic aortic surgery (AoS) with or without aortic valve replacement, with a sensitivity analysis based on a systematic review. Scenario analyses were provided for other aortic dimensions. Implications for survival, quality-adjusted life years (QALYs), and costs were calculated from healthcare delivery and economic perspectives. After 10 000 simulations for the reference case, the utility of watchful waiting (WW) exceeded that of elective AoS (13 ± 4 vs. 10 ± 5 QALY). The net monetary benefit was A$351 063 ± 304 965 with immediate AoS vs. 534 797 ± 198 570 with WW surveillance. The most important variables affecting effectiveness were utility value of survivors, rate of aortic growth, and probability of acute aortic event during WW.

Conclusions

This decision-analytic model informed by our practice, as well as a systematic analysis, shows that AoS in a BAV patient with aorta <5 cm diameter is costlier and less effective than WW.

The bicuspid aortic valve: Is it an immunological disease process?

Bicuspid aortic valves (BAVs) are the most common congenital cardiac condition and are characterized by a structural abnormality whereby the aortic valve is composed of two leaflets instead of being trileaflet. It is linked to an increased risk for a variety of complications of the aorta, many with an immunological pathogenesis. The aim of this study is to review and analyze the literature regarding immunological processes involving BAVs, associated common pathologies, and their incidence in the population. This study will also examine current trends in surgical and therapeutic approaches to treatment and discuss the future direction of BAV treatment.

Symptoms Matter: A Symptomatic but Radiographically Elusive Ascending Aortic Dissection

Symptoms attributable to a thoracic aortic aneurysm (TAA) are a separate indication for prophylactic repair, irrespective of aortic size. We present the case of a 56-year-old female with a history of a thoracic ascending aortic aneurysm (TAAA) and four other heart and arch vessel abnormalities who presented to us with chest pain radiating to her back. Computed Tomography and echocardiography showed no evidence of a dissection and revealed a maximal ascending aortic diameter of 4.2 cm. The patient subsequently underwent root-sparing ascending aortic and hemiarch replacement due to her threatening symptomatology. A focal dissection was discovered intraoperatively, resembling a similar case previously reported by our team.

Left ventricular geometric patterns in patients with type A aortic dissection

BACKGROUND

Aortic dilatation is a major risk factor for aortic dissection. The aim of the present study was to assess the relationship between left ventricular (LV) geometry and maximal ascending aorta (MAA).

METHODS

We reviewed data from patients who were diagnosed with acute type A aortic dissection and who underwent surgical management from December 2002 to March 2016 at Dong-A University Hospital. Among 151 patients with non-Marfan aortic dissection in the study, 50 who had echocardiography preoperatively were investigated and MAA diameter was analyzed by LV geometric patterns.

RESULTS

Patients' mean age was 59.6 ± 13.5 years and 38.0% were male. The mean MAA diameter was 52.9 ± 8.5 mm. MAA diameter was significantly correlated with LV mass index (r = 0.62, P < 0.001). On analysis by LV geometry, MAA diameter showed a significant difference between the 4 groups (P = 0.02), and the eccentric and concentric hypertrophy groups showed significantly larger MAA diameter than the other two groups.

CONCLUSION

MAA diameter was associated with LV mass index and was significantly different between LV geometry types. In this study, not only concentric hypertrophy but also eccentric LV hypertrophy was related to larger MAA in type A aortic dissection patients.

The fate of unrepaired chronic type A aortic dissection

OBJECTIVES

The current guidelines do not consider chronic type A aortic dissection as one of the triggers for prophylactic aortic repair, and an aortic diameter of 55 mm is considered the threshold for surgery.

METHODS

From the institutional database, we retrieved 82 patients who were diagnosed as having chronic type A aortic dissection but did not undergo immediate surgical repair from 1997 to 2016. The primary outcome was a composite of adverse aortic events defined as aortic rupture and sudden death. Conversion to elective surgery during follow-up was regarded as competing risk for adverse events.

RESULTS

The median value of the maximal aortic diameter at baseline was 55.2 mm. During a median follow-up of 77.1 months, 19 adverse events occurred while 9 patients received elective aortic repair. On multivariable competing risk analyses, baseline aortic diameter and age emerged as significant and independent factors associated with aortic events. The estimated rates of aortic event within 5 years were 12.0%, 19.4%, and 29.7% for aortic diameters of 50, 60, and 70 mm, respectively, with escalating risk rates as age increased for the given aortic diameters.

CONCLUSIONS

In unrepaired chronic type A aortic dissection, aortic events were not infrequent even for patients with an aortic diameter of less than 55 mm. This finding indicates that there may be a need to lower the surgical threshold for chronic type A aortic dissection.

Development and validation of a nomogram predicting the probability of type a aortic dissection at a diameter below 55 mm: A retrospective cohort study

INTRODUCTION

The study aims to build and validate a nomogram for estimating the probability of patients developing type A aortic dissection at a diameter less than 55 mm.

METHODS

A primary cohort of 896 patients diagnosed with acute type A aortic dissection by computed tomography angiography (CTA) were used for model development, with data collected between January 2005 and March 2012. The subjects were assigned to two groups based on ascending aorta diameter (group A<55 mm, Group B ≥ 60 mm). Univariate and multivariate logistic regression analyses were employed for the development of the prediction model. Demographic factors, as well as clinical and imaging characteristics were taken into account. The resulting nomogram was evaluated for performance traits, e.g. calibration, discrimination and clinical usefulness. After internal validation, the nomogram was further assessed in a different cohort containing 385 consecutive subjects examined between January 2013 and December 2015.

RESULTS

The individualized prediction nomogram included 9 predictors derived from univariate and multivariable analyses, including gender, age, weight, hypertension, liver cyst, renal cyst, bicuspid aortic valve, and bovine arch. Those predictors were double confirmed with Lasso regression. Internal validation showed good discrimination of the model with area under the curve (AUC) of 0.854 and good calibration (Hosmer-Lemeshow test, P = 0.876). Application of the nomogram in the validation cohort still revealed good discrimination (AUC = 0.802) and good calibration (Hosmer-Lemeshow test, P = 0.398). Decision curve analysis demonstrated that the prediction nomogram was clinically useful.

CONCLUSIONS

The current work presents a prediction nomogram incorporating demographical data as well as clinical and imaging characteristics that could help identify patients who might develop type A aortic dissection at a diameter less than 55 mm with convenience.

Morphological features of the thoracic aorta and supra-aortic branches in patients with acute Type A aortic dissection in China

OBJECTIVES

This study aimed to investigate the morphological characteristics of the dissected thoracic aorta and brachiocephalic arteries within the Chinese population.

METHODS

A retrospective analysis of computed tomography scans of 387 patients with acute Type A aortic dissection was carried out. The dimensions of the thoracic aorta at multiple levels and other imaging characteristics were studied.

RESULTS

The patients with a maximum diameter ≥55 mm accounted for less than one-third of the population. Among those without Marfan syndrome (MFS) (n = 349), only 114 (32.8%) patients had a maximal aortic diameter ≥ 55 mm, whereas among those with MFS (n = 38), 20 (78.9%) had a maximal aortic diameter ≥ 45 mm. The predicted maximum aortic diameter is 88.46 - 0.81 × height (cm) + 63.02 × body surface area (m2) + 5.50 × (if diabetes, 1, if not, 0) - 6.63 × (if hypertension, 1, if not, 0). A positive correlation was established between a circular false lumen and the probability that brachiocephalic arteries were involved by dissection. The size ratio of false lumen to true lumen was greater in the circumferential group when compared with the crescent group. The independent predictors for the circumferential false lumen were age, atherosclerosis and smoking.

CONCLUSIONS

Herein, the morphological characteristics of the thoracic aorta among Chinese patients with acute Type A aortic dissection were described. The currently recommended criteria for prophylactic aorta surgery were applied to most patients with MFS but not to those without MFS within the Chinese population. Furthermore, the shape of the false lumen was identified as a putative risk factor that might affect the prognosis of the patients.

Age-related changes of shape and flow dynamics in healthy adult aortas: A 4D flow MRI study

BACKGROUND

Abnormal flow dynamics play an early and causative role in pathologic changes of the ascending aorta.

PURPOSE

To identify: 1) the changes in flow, shape, and size that occur in the ascending aorta with normal human ageing and 2) the influence of these factors on aortic flow dynamics.

STUDY TYPE

Retrospective.

SUBJECTS

In all, 247 subjects (age range 19-86 years, mean 49 ± 17.7, 169 males) free of aortic or aortic valve pathology were included in this study. Subjects were stratified by youngest (18-33 years; n = 64), highest (>60 years, n = 67), and the middle two quartiles (34-60 years, n = 116).

FIELD STRENGTH/SEQUENCE

Subjects underwent a cardiac MRI (3T) exam including 4D-flow MRI of the aorta.

ASSESSMENT

Aortic curvature, arch shape, ascending aortic angle, ascending aortic diameter, and the stroke volume normalized by the aortic volume (nSV) were measured. Velocity, vorticity, and helicity were quantified across the thoracic aorta.

STATISTICAL TESTS

Univariate and multivariate regressions were used to quantify continuous relationships between variables.

RESULTS

Aortic diameter, ascending aortic angle, shape, and curvature all increased across age while nSV decreased (all P < 0.0001). Systolic vorticity in the mid arch decreased by 50% across the age range (P < 0.0001), while peak helicity decreased by 80% (P < 0.0001). Curvature tightly governs optimal flow in the youngest quartile, with an effect size 1.5 to 4 times larger than other parameters in the descending aorta, but had a minimal influence with advancing age. In the upper quartile of age, flow dynamics were almost completely determined by nSV, exerting an effect size on velocity and vorticity >10 times that of diameter and other shape factors.

DATA CONCLUSION

Aortic shape influences flow dynamics in younger subjects. Flow conditions become increasingly disturbed with advancing age, and in these conditions nSV has a more dominant effect on flow patterns than shape factors.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2019;49:90-100.

Association of Mortality and Acute Aortic Events With Ascending Aortic Aneurysm: A Systematic Review and Meta-analysis

IMPORTANCE

The natural history of ascending aortic aneurysm (AsAA) is currently not well characterized.

OBJECTIVE

To summarize and analyze existing literature on the natural history of AsAA.

DATA SOURCES

A search of Ovid MEDLINE (January 1, 1946, to May 31, 2017) and Embase (January 1, 1974, to May 31, 2017) was conducted.

STUDY SELECTION

Studies including patients with AsAA were considered for inclusion; studies were excluded if they considered AsAA, arch, and descending thoracic aneurysm as 1 entity or only included descending aneurysms, patients with heritable or genetic-related aneurysms, patients with replaced bicuspid aortic valves, patients with acute aortic syndrome, or those with mean age less than 16 years. Two independent reviewers identified 20 studies from 7198 unique studies screened.

DATA EXTRACTION AND SYNTHESIS

Data extraction was performed according to the Meta-analysis of Observational Studies in Epidemiology (MOOSE) reporting guideline; 2 reviewers independently extracted the relevant data. Summary effect measures of the primary outcomes were obtained by logarithmically pooling the data with an inverse variance-weighted random-effects model. Metaregression was performed to assess the relationship between initial aneurysm size, etiology, and the primary outcomes.

MAIN OUTCOMES AND MEASURES

The primary composite outcome was incidence of all-cause mortality, aortic dissection, and aortic rupture. Secondary outcomes were growth rate, incidence of proximal aortic dissection or rupture, elective ascending aortic repair, and all-cause mortality.

RESULTS

Twenty studies consisting of 8800 patients (mean [SD] age, 57.75 [9.47] years; 6653 [75.6%] male) with a total follow-up time of 31 823 patient-years were included. The mean AsAA size at enrollment was 42.6 mm (range, 35.5-56.0 mm). The combined effect estimate of annual aneurysm growth rate was 0.61 mm/y (95% CI, 0.23-0.99 mm/y). The pooled incidence of elective aortic surgery was 13.82% (95% CI, 6.45%-21.41%) over a median (interquartile range) follow-up of 4.2 (2.9-15.0) years. The linearized mortality rate was 1.99% per patient-year (95% CI, 0.83%-3.15% per patient-year), and the linearized rate of the composite outcome of all-cause mortality, aortic dissection, and aortic rupture was 2.16% per patient-year (95% CI, 0.79%-3.55% per patient year). There was no significant relationship between year of study completion and the initial aneurysm size and primary outcomes.

CONCLUSIONS AND RELEVANCE

The growth rate of AsAA is slow and has implications for the interval of imaging follow-up. The data on the risk of dissection, rupture, and death of ascending aortic aneurysm are limited. A randomized clinical trial may be required to understand the benefit of surgical intervention compared with surveillance for patients with moderately dilated ascending aorta.

Aortic valve-mediated wall shear stress is heterogeneous and predicts regional aortic elastic fiber thinning in bicuspid aortic valve-associated aortopathy

OBJECTIVES

The objectives of this study were to investigate an association between the magnitude of flow-mediated aortic wall shear stress (WSS) and medial wall histopathology in patients with bicuspid aortic valve (BAV) with aortopathy.

METHODS

Patients with BAV (n = 27; 52 ± 15 years; 3 women; proximal thoracic aorta diameter = 4.4 ± 0.7 and 4.6 ± 0.5 cm) who underwent prophylactic aortic resection received preoperative 3-dimensional time-resolved phase-contrast magnetic resonance imaging with 3-dimensional velocity encoding to quantify WSS relative to a population of healthy age- and sex-matched tricuspid aortic valve control participants (n = 20). Quantitative histopathology was conducted on BAV aorta tissue samples resected at surgery (n = 93), and correlation was performed between elastic fiber thickness and in vivo aortic WSS as continuous variables. Validation of elastic fiber thickness was achieved by correlation relative to tissue stiffness determined using biaxial biomechanical testing (n = 22 samples).

RESULTS

Elastic fibers were thinner and WSS was higher along the greater curvature compared with other circumferential regions (vs anterior wall: P = .003 and P = .0001, respectively; lesser curvature: both P = .001). Increased regional WSS was associated with decreased elastic fiber thickness (r = -0.25; P = .02). Patient stratification with subanalysis showed an increase in the correlation between WSS and histopathology with aortic valve stenosis (r = -0.36; P = .002) and smaller aortic diameters (<4.5 cm: r = -0.39; P = .03). Elastic fiber thinning was associated with circumferential stiffness (r = -0.41; P = .06).

CONCLUSIONS

For patients with BAV, increased aortic valve-mediated WSS is significantly associated with elastic fiber thinning, particularly with aortic valve stenosis and in earlier stages of aortopathy. Elastic fiber thinning correlates with impaired tissue biomechanics. These novel findings further implicate valve-mediated hemodynamics in the progression of BAV aortopathy.