Ascending Aortic Length and Its Association With Type A Aortic Dissection

Impact of nondiameter aortic indices on surgical eligibility: Results from the Treatment in Thoracic Aortic Aneurysm: Surgery Versus Surveillance (TITAN: SvS) randomized controlled trial

OBJECTIVES

Traditional criterion for intervention on an asymptomatic ascending aortic aneurysm has been a maximal aortic diameter of 5.5 cm or more. The 2022 American College of Cardiology/American Heart Association aortic guidelines adopted cross-sectional aortic area/height ratio, aortic size index, and aortic height index as alternate parameters for surgical intervention. The objective of this study was to evaluate the impact of using these newer indices on patient eligibility for surgical intervention in a prospective, multicenter cohort with moderate-sized ascending aortic aneurysms between 5.0 and 5.4 cm.

METHODS

Patients enrolled from 2018 to 2023 in the randomization or registry arms of the multicenter trial, Treatment In Thoracic Aortic aNeurysm: Surgery versus Surveillance, were included in the study. Clinical data were captured prospectively in an online database. Imaging data were derived from a core computed laboratory.

RESULTS

Among the 329 included patients, 20% were female. Mean age was 65.0 ± 11.6 years, and mean maximal aortic diameter was 50.8 ± 3.9 mm. In the one-third of all patients (n = 109) who met any 1 of the 3 criteria (ie, aortic size index ≥3.08 cm/m2, aortic height index ≥3.21 cm/m, or cross-sectional aortic area/height ≥ 10 cm2/m), their mean maximal aortic diameter was 52.5 ± 0.52 mm. Alternate criteria were most commonly met in women compared with men: 20% versus 2% for aortic size index (P < .001), 39% versus 5% for aortic height index (P < .001), and 39% versus 21% for cross-sectional aortic area/height (P = .002), respectively.

CONCLUSIONS

One-third of patients in Treatment In Thoracic Aortic aNeurysm: Surgery versus Surveillance would meet criteria for surgical intervention based on novel parameters versus the classic definition of diameter 5.5 cm or more. Surgical thresholds for aortic size index, aortic height index, or cross-sectional aortic area/height ratio are more likely to be met in female patients compared with male patients.

The correlation study between the length and angle of ascending aortic and the incidence risk of acute type A aortic dissection

Objective

This study utilized computed tomography angiography (CTA) to assess the risk of acute type A aortic dissection (ATAAD) by analyzing the imaging morphology indicators of the ascending aorta, along with the relevant risk factors associated with aortic dissection.

Methods

The study utilized a retrospective observational research design. The population consisted of 172 patients who received treatment in the Department of Cardiothoracic Surgery at Qilu Hospital, Shandong University, from January 2018 to December 2022. The patients were divided into two groups: the ATAAD group (n = 97) and the thoracic aortic aneurysm group (TAA, n = 75). Demographic data and ascending aorta CTA measurements were collected from all patients. Single factor and multivariate logistic regression were employed to analyze the statistical differences in clinical data and ascending aorta CTA imaging morphology indicators between the two groups.

Results

The variables were included in logistic multivariate analysis for further screening, indicating that the length of the ascending aorta (LAA) before ATAAD (OR = 3.365; 95% CI :1.742-6.500, P<0.001), ascending arch angle (asc-arch angle, OR = 0.902; 95% CI: 0.816-0.996, P = 0.042) and the maximum aortic diameter (MAD) before ATAAD, (OR = 0.614; 95% CI: 0.507-0.743, P<0.001) showed statistically significant differences.

Conclusions

This study suggests that increased LAA and MAD, as well as a smaller asc-arch angle may be high-risk factors for the onset of ATAAD.

Morphological risk of acute type A aortic dissection in the mildly to moderately dilated aorta

OBJECTIVES

This study aimed to analyse and determine the role of aortic length and curvature in the pathogenesis of acute type A aortic dissection (ATAAD) with ascending aortic diameters (AADs) <5 cm.

METHODS

We reviewed the clinical and imaging data of patients with ATAAD (n = 201) and ascending aortic dilation (n = 83). Thoracic aortic bending index (TABI) was used to quantify aortic curvature and analyse its role in ATAAD below the diameter risk threshold.

RESULTS

The AAD was <5.0 and <4.0 cm in 78% and 37% of patients with ATAAD, respectively. The median ascending aortic length (AAL) was 104.6 mm (Q1-Q3, 96.5-113.6 mm), and in 62.7% of patients, it was <11 cm. The median TABI was 14.99 mm/cm (Q1-Q3, 14.18-15.86 mm/cm). Patients with ATAAD and those with aortic dilation were matched for AAD, age, sex, height and other clinical factors. After matched, the dissection group had higher AALs (median, 102.9 mm; Q1-Q3, 96.0-112.5 mm vs median, 88.2 mm; Q1-Q3, 83.7-95.9 mm; P < 0.001) and TABI (median, 14.84 mm/cm; Q1-Q3, 14.06-15.83 mm/cm vs median, 13.55 mm/cm; Q1-Q3, 13.03-14.28 mm/cm; P < 0.001). According to the regression analysis, the area under the curve required to distinguish patients with ATAAD from those with aortic dilation was 0.831 in AAL, 0.837 in TABI and 0.907 when AAL was combined with TABI.

CONCLUSIONS

The patients with ATAAD had higher AAL and TABI than those with aortic dilation. The combination of TABI and AAL might be a potential morphological marker for determining ATAAD risk below the current aortic diameter risk threshold.

Age is superior to aortopathy phenotype as a predictor of aortic mechanics in patients with bicuspid valve

OBJECTIVES

Bicuspid aortic valve (BAV) aortopathy is defined by 3 phenotypes-root, ascending, and diffuse-based on region of maximal aortic dilation. We sought to determine the association between aortic mechanical behavior and aortopathy phenotype versus other clinical variables.

METHODS

From August 1, 2016, to March 1, 2023, 375 aortic specimens were collected from 105 patients undergoing elective ascending aortic aneurysm repair for BAV aortopathy. Planar biaxial data (191 specimens) informed constitutive descriptors of the arterial wall that were combined with in vivo geometry and hemodynamics to predict stiffness, stress, and energy density under physiologic loads. Uniaxial testing (184 specimens) evaluated failure stretch and failure Cauchy stress. Boosting regression was implemented to model the association between clinical variables and mechanical metrics.

RESULTS

There were no significant differences in mechanical metrics between the root phenotype (N = 33, 31%) and ascending/diffuse phenotypes (N = 72, 69%). Biaxial testing demonstrated older age was associated with increased circumferential stiffness, decreased stress, and decreased energy density. On uniaxial testing, longitudinally versus circumferentially oriented specimens failed at significantly lower Cauchy stress (50th [15th, 85th percentiles]: 1.0 [0.7, 1.6] MPa vs 1.9 [1.3, 3.1] MPa; P < .001). Age was associated with decreased failure stretch and stress. Elongated ascending aortas were also associated with decreased failure stress.

CONCLUSIONS

Aortic mechanical function under physiologic and failure conditions in BAV aortopathy is robustly associated with age and poorly associated with aortopathy phenotype. Data suggesting that the root phenotype of BAV aortopathy portends worse outcomes are unlikely to be related to aberrant, phenotype-specific tissue mechanics.

Successful Endovascular Treatment of an Anastomotic Pseudoaneurysm in the Ascending Aorta

We present a case of a 72-year-old-male with an ascending aortic anastomotic pseudoaneurysm following Dacron graft repair of an iatrogenic ascending aortic dissection that occurred during an open mitral valve repair, which was successfully treated with endovascular graft placement. In conclusion, this uncommon finding demonstrates a complex pathology and additional clinical examples of the versatility of endovascular stent grafts within the ascending aorta.

Acute aortic dissection

Although substantial progress has been made in the prevention, diagnosis, and treatment of acute aortic dissection, it remains a complex cardiovascular event, with a high immediate mortality and substantial morbidity in individuals surviving the acute period. The past decade has allowed a leap forward in understanding the pathophysiology of this disease; the existing classifications have been challenged, and the scientific community moves towards a nomenclature that is likely to unify the current definitions according to morphology and function. The most important pathophysiological pathway, namely the location and extension of the initial intimal tear, which causes a disruption of the media layer of the aortic wall, together with the size of the affected aortic segments, determines whether the patient should undergo emergency surgery, an endovascular intervention, or receive optimal medical treatment. The scientific evidence for the management and follow-up of acute aortic dissection continues to evolve. This Seminar provides a clinically relevant overview of potential prevention, diagnosis, and management of acute aortic dissection, which is the most severe acute aortic syndrome.

Gender differences in acute aortic syndromes

PURPOSE OF REVIEW

Acute aortic syndromes include acute aortic dissection, intramural hematoma, and penetrating aortic ulcer, and are associated with high mortality and morbidity. This review focuses on recent findings and current understanding of gender-related and sex-related differences in acute aortic syndromes.

RECENT FINDINGS

Large international and national registries, population studies, and multicentre national prospective cohort studies show evidence of sex differences in acute aortic syndromes. Recent studies of risk factors, aorta remodelling, and genetics provide possible biological basis for sex differences. The 2022 American College of Cardiology/American Heart Association Guidelines for the Diagnosis and Management of Aortic Disease revise recommendations for surgical management for aortic root and ascending aorta dilatation, which could impact outcome differences between the sexes.

SUMMARY

Acute aortic syndromes affect men more frequently than women. The prevalence of acute aortic syndromes and prevalence of many risk factors rise sharply with age in women leading to higher age at presentation for women. Times from symptom onset to presentation and presentation to diagnosis are delayed in female patients. Females with type A dissection are also more commonly treated conservatively than male counterparts. These factors likely contribute to higher early mortality and complications in women.

Ascending aortic geometry and its relationship to the biomechanical properties of aortic tissue

Objective

The objective of this study was to evaluate the relationship between ascending aortic geometry and biomechanical properties.

Methods

Preoperative computed tomography scans from ascending aortic aneurysm patients were analyzed using a center line technique (n = 68). Aortic length was measured from annulus to innominate artery, and maximal diameter from this segment was recorded. Biaxial tensile testing of excised tissue was performed to derive biomechanical parameters energy loss (efficiency in performing the Windkessel function) and modulus of elasticity (stiffness). Delamination testing (simulation of dissection) was performed to derive delamination strength (strength between tissue layers).

Results

Aortic diameter weakly correlated with energy loss (r ² = 0.10; P < .01), but not with modulus of elasticity (P = .13) or delamination strength (P = .36). Aortic length was not associated with energy loss (P = .87), modulus of elasticity (P = .13) or delamination strength (P = .90). Using current diameter guidelines, aortas >55 mm (n = 33) demonstrated higher energy loss than those <55 mm (n = 35; P = .05), but no difference in modulus of elasticity (P = .25) or delamination strength (P = .89). A length cutoff of 110 mm was proposed as an indication for repair. Aortas >110 mm (n = 37) did not exhibit a difference in energy loss (P = .40), modulus of elasticity (P = .69), or delamination strength (P = .68) compared with aortas <110 mm (n = 31). Aortas above diameter and length thresholds (n = 21) showed no difference in energy loss (P = .35), modulus of elasticity (P = .55), or delamination strength (P = .61) compared with smaller aortas (n = 47).

Conclusions

Aortic geometry poorly reflects the mechanical properties of aortic tissue. Weak association between energy loss and diameter supports intervention at larger diameters. Further research into markers that better capture aortic biomechanics is needed.

Relationship Between Length and Curvature of Ascending Aorta and Type a Dissection

Background

Type A aortic dissection (TAAD) has a rapid onset and high mortality. Currently, aortic diameter is the major criterion for evaluating the risk of TAAD. We attempted to find other aortic morphological indicators to further analyze their relationships with the risk of type A dissection.

Methods

We included the imaging and clinical data of 112 patients. The patients were divided into three groups, of which Group 1 had 49 patients with normal aortic diameter, Group 2 had 22 patients with ascending aortic aneurysm, and Group 3 had 41 patients with TAAD. We used AW Server software, version 3.2, to measure aorta-related morphological indicators.

Results

First, in Group 1, the univariate analysis results showed that ascending aortic diameter was correlated with patient age (r² = 0.35) and ascending aortic length (AAL) (r² = 0.43). AAL was correlated with age (r² = 0.12) and height (r² = 0.11). Further analysis of the aortic morphological indicators among the three groups found that the median aortic diameter was 36.20 mm in Group 1 (Q1–Q3: 33.40–37.70 mm), 42.5 mm in Group 2 (Q1–Q3: 41.52–44.17 mm) and 48.6 mm in Group 3 (Q1–Q3: 42.4–55.3 mm). There was no significant difference between Groups 2 and 3 (P > 0.05). Group 3 had the longest AAL (median: 109.4 mm, Q1–Q3: 118.3–105.3 mm), followed by Group 2 (median: 91.0 mm, Q1–Q3: 95.97–84.12 mm) and Group 1 (81.20 mm, Q1–Q3: 76.90–86.20 mm), and there were statistically significant differences among the three groups (P < 0.05). The Aortic Bending Index (ABI) was 14.95 mm/cm in Group 3 (Q1–Q3: 14.42–15.78 mm/cm), 13.80 mm/cm in Group 2 (Q1–Q3: 13.42–14.42 mm/cm), and 13.29 mm/cm in Group 1 (Q1–Q3: 12.71–13.78 mm/cm), and the difference was statistically significant in comparisons between any two groups (P < 0.05). Regression analysis showed that aortic diameter + AAL + ABI differentiated Group 2 and Group 3 with statistical significance (area under the curve (AUC) = 0.834), which was better than aortic diameter alone (AUC = 0.657; P < 0.05).

Conclusions

We introduced the new concept of ABI, which has certain clinical significance in distinguishing patients with aortic dissection and aneurysm. Perhaps the ascending aortic diameter combined with AAL and ABI could be helpful in predicting the occurrence of TAAD.

Association of dissected ascending aorta diameter with preoperative adverse events in patients with acute type A aortic dissection

BACKGROUND

Acute type A aortic dissection (ATAAD) is a life-threatening disease associated with high morbidity and mortality.

AIM

To evaluate the diameter of dissected ascending aorta in patients diagnosed with ATAAD and whether the aortic diameter is associated with preoperative adverse events.

METHODS

A total of 108 patients diagnosed with ATAAD who underwent emergency operation under hypothermic circulatory arrest were enrolled in this study. Demographic characteristics and perioperative data were recorded. In all patients, preoperative chest and abdomen computed tomography (CT) scans were performed.

RESULTS

Median age of the patients was 61.5 (52.5-70.5) years and median body mass index (BMI) was 28.2 (25.1-32.6) cm². The number of female patients was 37 (25%). Median diameter of the ascending aorta was 5.0 (4.5-6) cm and 53.8% of the patients had an aortic diameter < 5.0 cm, while 32.3% of the patients had an aortic diameter of 4.5cm and 72.0% had an ascending aorta diameter < 5.5 cm. The diameter of the ascending aorta did not differ in patients with vs without preoperative adverse events: Preoperative neurological dysfunction (P = 0.53) and hemodynamic instability (P = 0.43). Median age of patients with preoperative hemodynamic instability was 65 (57.5-74) years, while it was 60 (51-68) years in patients without (P = 0.04)

CONCLUSION

Although current guidelines suggest replacing the ascending aorta with a diameter > 5.5 cm, most of the patients with ATAAD had an aortic diameter of less than 5.5 cm. The diameter of the ascending aorta in patients diagnose with ATAAD is not associated with preoperative adverse events.

Ascending Aortic Length and Its Association With Type A Aortic Dissection

Background

The aim of this study was to determine the role of ascending aortic length and diameter in type A aortic dissection.

Methods and Results

Computed tomography scans from patients with acute type A dissections (n=51), patients with proximal thoracic aortic aneurysms (n=121), and controls with normal aortas (n=200) were analyzed from aortic annulus to the innominate artery using multiplanar reconstruction. In the control group, ascending aortic length correlated with diameter (r²=0.35, P<0.001), age (r²=0.17, P<0.001), and sex (P<0.001). As a result of immediate changes in aortic morphology at the time of acute dissection, predissection lengths and diameters were estimated based on models from published literature. Ascending aortic length was longer in patients immediately following acute dissection (median, 109.7 mm; interquartile range [IQR], 101.0–115.1 mm), patients in the estimated predissection group (median, 104.2 mm; IQR, 96.0–109.3 mm), and patients in the aneurysm group (median, 107.0 mm; IQR, 99.6–118.7 mm) in comparison to controls (median, 83.2 mm; IQR, 74.5–90.7 mm) (P<0.001 all comparisons). The diameter of the ascending aorta was largest in the aneurysm group (median, 52.0 mm; IQR, 45.9–58.0 mm), followed by the dissection group (median, 50.3 mm; IQR, 46.6–57.5 mm), and not significantly different between controls and the estimated predissection group (median, 33.4 mm [IQR, 30.7–36.7 mm] versus 35.2 mm [IQR, 32.6–40.3 mm], P=0.09). After adjustment for diameter, age, and sex, the estimated predissection aortic lengths were 16 mm longer than those in the controls and 12 mm longer than in patients with nondissected thoracic aneurysms.

Conclusions

The length of the ascending aorta, after adjustment for age, sex, and aortic diameter, may be useful in discriminating patients with type A dissection from normal controls and patients with nondissected thoracic aneurysms.