Obtaining the biomechanical behavior of ascending aortic aneurysm by using novel speckle tracking echocardiography

Introduction: Ex vivo measurement of ascending aortic biomechanical properties may help in the process of estimating the risk for rupture or dissection of dilated ascending aortas. A validated in vivo method that can predict aortic biomechanics does not exist. Speckle tracking transesophageal echocardiography (TEE) has been used to measure ventricular stiffness; we sought to determine if speckle-tracking echocardiography could be adopted to estimate aortic stiffness in vivo and compare these findings to those obtained by ex vivo tissue measurements.Methods: 17 patients undergoing ascending aortic resection were recruited to be part of the study with the mean aortic diameter of 56.16 ± 15 mm. Intra-operative speckle tracking echocardiographic analysis was used to calculate aortic stiffness index using the following equation:β2= ln⁡〖(SBP⁄(DBP))〗⁄AoS (β2 stiffness index; SBP: Systolic BP; DBP: Diastolic BP, AoS: circumferential strain). Ex vivo stiffness was obtained by mechanical tissue testing according to previously described methods. The aortic ring at the pulmonary trunk was divided into four equal quadrantsResults: the mean aortic diameter was. The in vivo stiffness index for the inner curvature, anterior wall, outer curvature and posterior wall were 0.0544 ± 0.0490, 0.0295± 0.0199, 0.0411± 0.0328 and 0.0502± 0.0320 respectively. The mean ex vivo 25% apparent stiffness for inner curvature, anterior wall, outer curvature and posterior wall were 0.0616 ±0.0758 MPa, 0.0352± 0.00992 MPa, 0.0405± 0.0199 MPa and 0.0327± 0.0106 MPa respectively. The patient matched ex vivo 25% apparent stiffness and in vivo stiffness index were not significantly different (p=0.8617, two way ANOVA with repeated measures). Conclusion: The use of speckle tracking TEE appears to be a promising technique to estimate ex vivo mechanical properties of the ascending aortic tissue.Introduction: Déterminer les propriétés biomécaniques ex vivo de l'aorte ascendante pourrait aider à obtenir de meilleures estimations de risques de ruptures et dissections du tissu dans le cas de dilatations. Aucune méthode permettant la prédiction du comportement mécanique du tissu aortique in vivo n'a encore été validée.L'échographie transoesophagienne de suivi des marqueurs acoustique est utilisée pour mesurer la rigidité du ventricule ; dans le cadre de cette étude, nous avons cherché à déterminer si une telle technique pouvait également être utilisée dans l'estimation de la rigidité de l'aorte in vivo en comparant les résultats mesurés à des données obtenues au préalable en ex vivo.Méthodes: 17 patients ayant subi une ablation de l'aorte ascendante avec un diamètre moyen de 56.16 ± 15 mm ont fait parti de l'étude. L'analyse de l'échographie transoesophagienne preopératoire de suivi des marqueurs acoustique a permis le calcul de la rigidité aortique en utilisant l'équation suivante β2= ln⁡〖(SBP⁄(DBP))〗⁄AoS, (β2 rigidité; SBP: Pression systolique; DBP: Pression diastolique, AoS: Déformations circonférentielles). La rigidité du tissu a été obtenue ex vivo par des tests mécaniques en suivant des méthodes décrites dans de précédentes études. Enfin, l'anneau aortique au tronc pulmonaire fut divisé en quatre quadrants de tailles égales.Résultats: Les rigidités in vivo de la courbure intérieure, paroi antérieure, courbure extérieure et paroi postérieure étaient de 0.0544 ± 0.0490, 0.0295± 0.0199, 0.0411± 0.0328 et 0.0502± 0.0320. Tandis que les moyennes ex vivo de la rigidité mesurée à 25% pour la courbure intérieure, paroi antérieure, courbure extérieure et paroi postérieure étaient de 0.0616 ±0.0758 MPa, 0.0352± 0.00992 MPa, 0.0405± 0.0199 MPa et 0.0327± 0.0106 MPa. Des résultats similaires ont été trouvés chez les patients entre les rigidités ex vivo (mesurées à 25%) et in vivo avec une différence non significative (p=0.8617, analyse ANOVA double avec des mesures répétées).Conclusion: L'utilisation de l'échographie transoesophagienne de suivi des marqueurs acoustique semble donc être une technique prometteuse permettant l'estimation de propriétés mécaniques du tissu de l'aorte ascendante in vivo

Investigation on the Regional Loss Factor and Its Anisotropy for Aortic Aneurysms

An aortic aneurysm is a lethal arterial disease that mainly occurs in the thoracic and abdominal regions of the aorta. Thoracic aortic aneurysms are prevalent in the root/ascending parts of the aorta and can lead to aortic rupture resulting in the sudden death of patients. Understanding the biomechanical and histopathological changes associated with ascending thoracic aortic aneurysms (ATAAs), this study investigates the mechanical properties of the aorta during strip-biaxial tensile cycles. The loss factor—defined as the ratio of dissipated energy to the energy absorbed during a tensile cycle—the incremental modulus, and their anisotropy indexes were compared with the media fiber compositions for aneurysmal (n = 26) and control (n = 4) human ascending aortas. The aneurysmal aortas were categorized into the aortas with bicuspid aortic valves (BAV) and tricuspid aortic valves (TAV). The strip-biaxial loss factor correlates well with the diameter of the aortas with BAV and TAV (for the axial direction, respectively, R2 = 0.71, p = 0.0022 and R2 = 0.54, p = 0.0096). The loss factor increases significantly with patients’ age in the BAV group (for the axial direction: R2 = 0.45, p = 0.0164). The loss factor is isotropic for all TAV quadrants, whereas it is on average only isotropic in the anterior and outer curvature regions of the BAV group. The results suggest that loss factor may be a useful surrogate measure to describe the histopathology of aneurysmal tissue and to demonstrate the differences between ATAAs with the BAV and TAV

Trends in Characteristics and Outcomes of Patients Undergoing Coronary Revascularization in the United States, 2003-2016.

Importance: Data on the contemporary changes in risk profile and outcomes of patients undergoing percutaneous coronary intervention (PCI) or coronary bypass grafting (CABG) are limited. Objective: To assess the contemporary trends in the characteristics and outcomes of patients undergoing PCI or CABG in the United States. Design, Setting, and Participants: This retrospective cohort study used a national inpatient claims-based database to identify patients undergoing PCI or CABG from January 1, 2003, to December 31, 2016. Data analysis was performed from July 15 to October 4, 2019. Main Outcomes and Measures: Demographic characteristics, prevalence of risk factors, and clinical presentation divided into 3 eras (2003-2007, 2008-2012, and 2013-2016) and in-hospital mortality of PCI and CABG stratified by clinical indication. Results: A total of 12 062 081 revascularization hospitalizations were identified: 8 687 338 PCIs (72.0%; mean [SD] patient age, 66.0 [10.8] years; 66.2% male) and 3 374 743 CABGs (28.0%; mean [SD] patient age, 64.5 [12.4] years; 72.1% male). The annual PCI volume decreased from 366 to 180 per 100 000 US adults and the annual CABG volume from 159 to 82 per 100 000 US adults. A temporal increase in the proportions of older, male, nonwhite, and lower-income patients and in the prevalence of atherosclerotic and nonatherosclerotic risk factors was found in both groups. The percentage of revascularization for myocardial infarction (MI) increased in the PCI group (22.8% to 53.1%) and in the CABG group (19.5% to 28.2%). Risk-adjusted mortality increased slightly after PCI for ST-segment elevation MI (4.9% to 5.3%; P \u3c .001 for trend) and unstable angina or stable ischemic heart disease (0.8% to 1.0%; P \u3c .001 for trend) but remained stable after PCI for non-ST-segment elevation MI (1.6% to 1.6%; P = .18 for trend). Risk-adjusted CABG morality markedly decreased in patients with MI (5.6% to 3.4% for all CABG and 4.8% to 3.0% for isolated CABG) and in those without MI (2.8% to 1.7% for all CABG and 2.1% to 1.2% for isolated CABG) (P \u3c .001 for all). Conclusions and Relevance: Significant changes were found in the characteristics of patients undergoing PCI and CABG in the United States between 2003 and 2016. Risk-adjusted mortality decreased significantly after CABG but not after PCI across all clinical indications

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population