Risk reduction and pharmacological strategies to prevent progression of aortic aneurysms

Analysis of Vascular Smooth Muscle Cells from Thoracic Aortic Aneurysms Reveals DNA Damage and Cell Cycle Arrest as Hallmarks in Bicuspid Aortic Valve Patients

Thoracic aortic aneurysm (TAA) is mainly sporadic and with higher incidence in the presence of a bicuspid aortic valve (BAV) for unknown reasons. The lack of drug therapy to delay TAA progression lies in the limited knowledge of pathophysiology. We aimed to identify the molecular hallmarks that differentiate the aortic dilatation associated with BAV and tricuspid aortic valve (TAV). Aortic vascular smooth muscle cells (VSMCs) isolated from sporadic TAA patients with BAV or TAV were analyzed by mass spectrometry. DNA oxidative damage assay and cell cycle profiling were performed in three independent cohorts supporting proteomics data. The alteration of secreted proteins was confirmed in plasma. Stress phenotype, oxidative stress, and enhanced DNA damage response (increased S-phase arrest and apoptosis) were found in BAV-TAA patients. The increased levels of plasma C1QTNF5, LAMA2, THSB3, and FAP confirm the enhanced stress in BAV-TAA. Plasma FAP and BGN point to an increased inflammatory condition in TAV. The arterial wall of BAV patients shows a limited capacity to counteract drivers of sporadic TAA. The molecular pathways identified support the need of differential molecular diagnosis and therapeutic approaches for BAV and TAV patients, showing specific markers in plasma which may serve to monitor therapy efficacy.

Development of a Prediction Model for Ascending Aortic Diameter Among Asymptomatic Individuals

IMPORTANCE

Ascending thoracic aortic disease is an important cause of sudden death in the US, yet most aortic aneurysms are identified incidentally.

OBJECTIVE

To develop and validate a clinical score to estimate ascending aortic diameter.

DESIGN, SETTING, AND PARTICIPANTS

Using an ongoing magnetic resonance imaging substudy of the UK Biobank cohort study, which had enrolled participants from 2006 through 2010, score derivation was performed in 30 018 participants and internal validation in an additional 6681. External validation was performed in 1367 participants from the Framingham Heart Study (FHS) offspring cohort who had undergone computed tomography from 2002 through 2005, and in 50 768 individuals who had undergone transthoracic echocardiography in the Community Care Cohort Project, a retrospective hospital-based cohort of longitudinal primary care patients in the Mass General Brigham (MGB) network between 2001-2018.

EXPOSURES

Demographic and clinical variables (11 covariates that would not independently prompt thoracic imaging).

MAIN OUTCOMES AND MEASURES

Ascending aortic diameter was modeled with hierarchical group least absolute shrinkage and selection operator (LASSO) regression. Correlation between estimated and measured diameter and performance for identifying diameter 4.0 cm or greater were assessed.

RESULTS

The 30 018-participant training cohort (52% women), were a median age of 65.1 years (IQR, 58.6-70.6 years). The mean (SD) ascending aortic diameter was 3.04 (0.31) cm for women and 3.32 (0.34) cm for men. A score to estimate ascending aortic diameter explained 28.2% of the variance in aortic diameter in the UK Biobank validation cohort (95% CI, 26.4%-30.0%), 30.8% in the FHS cohort (95% CI, 26.8%-34.9%), and 32.6% in the MGB cohort (95% CI, 31.9%-33.2%). For detecting individuals with an ascending aortic diameter of 4 cm or greater, the score had an area under the receiver operator characteristic curve of 0.770 (95% CI, 0.737-0.803) in the UK Biobank, 0.813 (95% CI, 0.772-0.854) in the FHS, and 0.766 (95% CI, 0.757-0.774) in the MGB cohorts, although the model significantly overestimated or underestimated aortic diameter in external validation. Using a fixed-score threshold of 3.537, 9.7 people in UK Biobank, 1.8 in the FHS, and 4.6 in the MGB cohorts would need imaging to confirm 1 individual with an ascending aortic diameter of 4 cm or greater. The sensitivity at that threshold was 8.9% in the UK Biobank, 11.3% in the FHS, and 18.8% in the MGB cohorts, with specificities of 98.1%, 99.2%, and 96.2%, respectively.

CONCLUSIONS AND RELEVANCE

A prediction model based on common clinically available data was derived and validated to predict ascending aortic diameter. Further research is needed to optimize the prediction model and to determine whether its use is associated with improved outcomes.

Smaller size is more suitable for pharmacotherapy among undersized abdominal aortic aneurysm: a systematic review and meta-analysis

Background: Pharmacotherapy for undersized abdominal aortic aneurysm (AAA) is a clinical unmet need. Randomized controlled trials (RCTs) have failed to show effectiveness despite countless promising data in preclinical studies. We aimed to identify the population with undersized AAAs (30-54 mm) who potentially benefit from pharmacotherapy. Methods: In accordance with the PRISMA statement, we conducted a systematic review and meta-analysis of placebo-controlled RCTs. The primary outcome was mean difference (MD) in annual growth rate (< 0 favors pharmacotherapy), and the secondary outcome was aneurysm-related events (diameters ⩾ 55 mm, ruptures, or referral to surgery). Results: Our search strategy identified eight RCTs (six trials on antibiotics [ABx], two on renin-angiotensin system inhibitors [RAS-I]) with a total of 1325 patients. The mean of baseline diameters ranged from 33.1 mm to 43.1 mm. Neither ABx nor RAS-I showed significant differences in MD. Multivariable random-effects restricted maximum likelihood meta-regression revealed a statistically significant linear relationship between baseline diameter and MD (coefficient 0.15 [95% CI 0.0011, 0.30], p = 0.049) but not for the follow-up period (p = 0.28) and duration of treatment (p = 0.11). In line with this result, ABx with baseline diameter < 40 mm significantly reduced MD (-1.03 mm/year [95% CI -1.64, -0.42], p = 0.001) and a borderline significant difference in aneurysm-related events (HR 0.53 [95% CI 0.28, 1.00], p = 0.05), whereas the other groups ⩾ 40 mm never demonstrated effectiveness. Fixed-effect models did not change the results. No evidence of publication bias was detected. Conclusion: Undersized AAAs < 40 mm can potentially benefit from pharmacotherapy. Future RCTs should consider preferentially including undersized AAA with smaller diameters.