Geometrical Factors Affect Wall Shear Stress in Saccular Aneurysms of the Infrarenal Abdominal Aorta.

BACKGROUND: Low wall shear stress (WSS) is predictive of aortic aneurysm growth and rupture. Yet, estimating WSS in a clinical setting is impractical, whereas measuring aneurysm geometry is feasible. This study investigates the association between saccular aneurysm geometry of the infrarenal aorta and WSS. METHODS: Starting with a nonaneurysmal, patient-specific, computational fluid dynamics model of the aorta, saccular aneurysms of varying geometry were created by incrementally increasing the neck width and sac depth from 1 cm to 4 cm. The aspect ratio (the ratio between sac depth and neck width) varied between 0.25 and 4. The peak WSS, time-averaged WSS (TAWSS), and oscillatory shear index (OSI) were measured within the aneurysm sac. RESULTS: Decreasing the neck width from 4 cm to 1 cm decreased the peak WSS by 69% and the TAWSS by 83%. Increasing the sac depth from 1 cm to 4 cm decreased the peak WSS by 55% and the OSI by 37%. The aspect ratio was negatively correlated to peak WSS (Rs -0.85; P < 0.001). CONCLUSIONS: In saccular aneurysms of the infrarenal aorta, a smaller neck width, deeper aneurysm sac, and larger aspect ratio are associated with lower peak WSS.

Outcomes of coronary artery bypass surgery using modified del Nido cardioplegia in patients with poor ventricular function.

BACKGROUND: del Nido cardioplegia (DN) has been shown to be safe in adult patients undergoing isolated coronary artery bypass grafting with normal left ventricular ejection fraction. We sought to determine whether it was also safe in adult patients with diminished left ventricular function. METHODS: All patients with preoperative left ventricular ejection fraction ≤ 40% undergoing isolated coronary artery bypass grafting between 1/1/2019 and 7/10/2022 were retrospectively analyzed. Off-pump and beating heart cases were excluded. Patients were divided by surgeon preference between conventional cardioplegia (CCP) and DN. Baseline and intraoperative characteristics and short-term postoperative outcomes were compared. RESULTS: Six surgeons performed 829 isolated coronary artery bypass operations during the study. Two-hundred seventy-two met study criteria. Three surgeons used exclusively CCP for the duration of the study, two used exclusively DN and one switched from CCP to DN mid-way through. Group totals were: CCP n = 181 and DN n = 91. There were no significant differences in baseline characteristics including mean left ventricular ejection fraction (CCP 32.5 ± 7.4% vs. DN 33.4 ± 7.29%, p = 0.939). Other than a significant decrease in bypass time for DN (113.20 ± 37.2 vs. 122.43 ± 34.3 min, p = 0.043) there were no intergroup differences in urgency, number of grafts, ischemic time or incidence of blood transfusion. Postoperative outcomes between CCP and DN were similar including incidence of atrial fibrillation (12.2% vs. 8.8%, p = 0.403), intensive care length of stay (3.7 ± 2.3 vs. 4.3 ± 3.7 days, p = 0.886), total length of stay (5.7 ± 3.7 vs. 6.3 ± 4.4 days, p = 0.922) and 30-day mortality (3.85% vs. 1.10%, p = 0.205). CONCLUSION: Compared to conventional cardioplegia, del Nido cardioplegia provides equivalent short-term outcomes in patients with low left ventricular ejection fraction undergoing isolated coronary artery bypass grafting.

Pulmonary Vein Thrombosis in the Setting of COVID-19 Infection: A Case Report.

The novel coronavirus SARS-CoV-2 (COVID-19) affects all three branches of Virchow's triad. It increases the risk of thrombosis and thromboembolic events. Pulmonary embolism and stroke are most commonly reported. However, there is an increasing number of cases demonstrating thrombosis in otherwise uncommon anatomical areas. In this presentation, we will explore the potential causes of pulmonary vein thrombosis secondary to COVID-19.