Michele Dell’aquila

Background: Arterial cannulation during cardiopulmonary bypass (CPB) significantly alters native aortic hemodynamics by generating a high-velocity jet that interacts with the ascending aorta and aortic arch geometry. These flow disturbances may influence wall shear stress (WSS), turbulence intensity, embolic trajectories, and cerebral perfusion. Cannula depth, orientation, and tip design have emerged as potentially important determinants of intra-aortic flow behavior. Materials and methods: A structured narrative review of the literature was conducted. PubMed/MEDLINE, Scopus, and Web of Science were searched from January 1990 to April 2025. Keywords included combinations of “aortic cannulation,” “cardiopulmonary bypass,” “computational fluid dynamics,” “wall shear stress,” “turbulence,” “atherosclerotic plaque,” “cerebral perfusion,” “microembolization,” “gaseous emboli,” “NIRS,” and “transcranial Doppler.” Studies were included if they evaluated hemodynamic effects of cannulation strategies using computational, in vitro, or clinical models. Articles not directly related to CPB intra-aortic flow dynamics were excluded. Results: The available evidence suggests that cannula positioning significantly influences intra-aortic flow behavior. Centrally aligned cannulation directed toward the descending thoracic aorta promotes axial flow and is associated with reduced jet-wall impingement and lower peak WSS. This configuration decreases arch turbulence and limits embolic transport toward supra-aortic vessels. Conclusion: Arterial cannulation strategy during CPB is a modifiable determinant of flow behavior and potential cerebral embolic exposure. Hemodynamically informed cannulation principles may contribute to intraoperative neuroprotection, although prospective clinical validation is still required.

The external stenting of saphenous vein grafts (SVGs) during coronary artery bypass grafting (CABG) has been proven to reduce intimal hyperplasia (IH) in animal models, paving the way for human randomized controlled trials (RCTs) to be conducted. Herein, we performed a study-level meta-analysis to assess the impact of the Venous External SupporT (VEST) device, an external stent, on the outcomes of SVGs. A systematic search was conducted to identify all RCTs comparing VEST-stented to non-stented SVGs in patients undergoing CABG. The primary outcome was graft occlusion. The main secondary outcomes were repeat revascularization, SVG IH area, and intimal-medial thickness. Two RCTs totaling 407 patients were included. At a mean follow-up of 1.5 years, there was no difference in graft occlusion between groups (incidence rate ratio: 1.11; 95% confidence interval (CI): 0.80–1.53). The rate of repeat revascularization was also similar (odds ratio: 0.66; 95% CI: 0.27–1.64). The IH area (standardized mean difference (SMD): −0.45; 95% CI: −0.79 to −0.10) and intimal-medial thickness (SMD: −0.50; 95% CI: −0.90 to −0.10) were significantly reduced in the VEST group. Our findings show that significant reductions in the IH area and the intimal-medial thickness in VEST-stented SVGs do not currently translate into a lesser need for repeat revascularization or less graft occlusion events compared to non-stented SVGs at 1.5 years after CABG.

Saphenous vein grafts (SVGs) are the most frequently used conduits in coronary artery bypass grafting (CABG), but their higher rate of occlusion compared to arterial conduits remains a concern. Previous studies have shown that SVG failure is mainly driven by intimal hyperplasia, an adaptative response to higher pressures of the arterial circulation. The VEST^TM device (Vascular Graft Solutions, Tel Aviv, Israel), an external support designed to mitigate intimal hyperplasia in SVGs, has been tested in few clinical trials (RCTs). Herein, we descriptively evaluated the randomized evidence on the VEST device.