Validation of a new model of selective antegrade cerebral perfusion with circulatory arrest in rats.

BACKGROUND: Selective antegrade cerebral perfusion (SACP) is adopted as an alternative to deep hypothermic circulatory arrest (DHCA) during aortic arch surgery. However, there is still no preclinical evidence to support the use of SACP associated with moderate hypothermia (28-30°C) instead of DHCA (18-20°C). The present study aims to develop a reliable and reproducible preclinical model of cardiopulmonary bypass (CPB) with SACP applicable for assessing the best temperature management. MATERIALS AND METHODS: A central cannulation through the right jugular vein and the left carotid artery was performed, and CPB was instituted.Animals were randomized into two groups: normothermic circulatory arrest without or with cerebral perfusion (NCA vs SACP). EEG monitoring was maintained during CPB. After 10 min of circulatory arrest, rats underwent 60 min of reperfusion. After that, animals were sacrificed, and brains were collected for histology and molecular biology analysis. RESULTS: Power spectral analysis of the EEG signal showed decreased activity in both cortical regions and lateral thalamus in all rats during the circulatory arrest. Only SACP determined complete recovery of brain activity and higher power spectral signal compared to NCA (p < 0.05). Histological damage scores and western blot analysis of inflammatory and apoptotic proteins like caspase-3 and Poly-ADP ribose polymerase (PARP) were significantly lower in SACP compared to NCA. Vascular endothelial growth factor (VEGF) and RNA binding protein 3 (RBM3) involved in cell-protection mechanisms were higher in SACP, showing better neuroprotection (p < 0.05). CONCLUSIONS: SACP by cannulation of the left carotid artery guarantees good perfusion of the whole brain in this rat model of CPB with circulatory arrest. The present model of SACP is reliable, repeatable, and not expensive, and it could be used in the future to achieve preclinical evidence for the best temperature management and to define the best cerebral protection strategy during circulatory arrest.

Twenty-Year Experience with Surgery for Native and Prosthetic Mitral Valve Endocarditis.

Background and Objectives: To evaluate the early and long-term results of surgical treatment of isolated mitral native and prosthetic valve infective endocarditis. Materials and Methods: All patients undergoing mitral valve repair or replacement for infective endocarditis at our institution between January 2001 and December 2021 were included in the study. The preoperative and postoperative characteristics and mortality of patients were retrospectively reviewed. Results: A total of 130 patients, 85 males and 45 females, with a median age of 61 ± 14 years, underwent surgery for isolated mitral valve endocarditis during the study period. There were 111 (85%) native and 19 (15%) prosthetic valve endocarditis cases. Fifty-one (39%) patients died during the follow-up, and the overall mean patient survival time was 11.8 ± 0.9 years. The mean survival time was better in patients with mitral native valve endocarditis compared to patients with prosthetic valve endocarditis (12.3 ± 0.9 years vs. 8 ± 1.4 years; p = 0.1), but the difference was not statistically significant. Patients who underwent mitral valve repair had a better survival rate compared to patients who had mitral valve replacement (14.8 ± 1.6 vs. 11.3 ± 1 years; p = 0.06); however, the difference was not statistically significant. Patients who underwent mitral valve replacement with a mechanical prosthesis had a significantly better survival rate compared to patients who received a biological prosthesis (15.6 ± 1.6 vs. 8.2 ± 0.8 years; p < 0.001). Patients aged ≤60 years had significantly better survival compared to patients aged >60 years (17.1 ± 1.1 vs. 8.2 ± 0.9; p < 0.001). Multivariate analysis showed that the patient's age >60 years at the time of surgery was an independent risk factor for mortality, while mitral valve repair was a protective factor. Eight (7%) patients required reintervention. Freedom from reintervention was significantly higher in patients with mitral native valve endocarditis compared to patients with prosthetic valve endocarditis (19.3 ± 0.5 vs. 11.5 ± 1.7 years; p = 0.04). Conclusions: Surgery for mitral valve endocarditis is associated with considerable morbidity and mortality. The patient's age at the time of surgery represents an independent risk factor for mortality. Mitral valve repair should be the preferred choice whenever possible in suitable patients affected by infective endocarditis.

Three Decades of Experience with Aortic Prosthetic Valve Endocarditis.

The objective of this study was to evaluate early and long-term outcomes of patients with aortic prosthetic valve endocarditis (a-PVE) treated with a prosthetic aortic valve (PAV), prosthetic valved conduit (PVC), or cryopreserved aortic homograft (CAH). A total of 144 patients, 115 male and 29 female, aged 67 ± 12 years, underwent surgery for a-PVE at our institution between 1994 and 2021. Median time from the original cardiac surgery was 1.9 [0.6-5.6] years, and 47 (33%) patients developed an early a-PVE. Of these patients, 73 (51%) underwent aortic valve replacement (AVR) with a biological or mechanical PAV, 12 (8%) underwent aortic root replacement (ARR) with a biological or mechanical PVC, and 59 (42%) underwent AVR or ARR with a CAH. Patients treated with a CAH had significantly more circumferential annular abscess multiple valve involvement, longer CPB and aortic cross-clamping times, and needed more postoperative pacemaker implantation than patients treated with a PAV. No difference was observed in survival, reoperation rates, or recurrence of IE between patients treated with a PAV, a PVC, or a CAH. CAHs are technically more demanding and more often used in patients who have extensive annular abscess and multiple valve involvement. However, the use of CAH is safe in patients with complex a-PVE, and it shows excellent early and long-term outcomes.

Turbulent blood dynamics in the left heart in the presence of mitral regurgitation: a computational study based on multi-series cine-MRI.

In this work, we performed a computational image-based study of blood dynamics in the whole left heart, both in a healthy subject and in a patient with mitral valve regurgitation. We elaborated multi-series cine-MRI with the aim of reconstructing the geometry and the corresponding motion of left ventricle, left atrium, mitral and aortic valves, and aortic root of the subjects. This allowed us to prescribe such motion to computational blood dynamics simulations where, for the first time, the whole left heart motion of the subject is considered, allowing us to obtain reliable subject-specific information. The final aim is to investigate and compare between the subjects the occurrence of turbulence and the risk of hemolysis and of thrombi formation. In particular, we modeled blood with the Navier-Stokes equations in the arbitrary Lagrangian-Eulerian framework, with a large eddy simulation model to describe the transition to turbulence and a resistive method to manage the valve dynamics, and we used a finite element discretization implemented in an in-house code for the numerical solution.