Background: Despite the successful development in cardiac surgery, cerebrovascular accidents (CVA) remain a devastating complication. Aortic atherosclerosis has been identified as a major risk factor for CVA. The present thesis addresses this question in relation to aortic manipulation during cardiac surgery, being divided into a clinical (I-II) and an experimental part (III-V). Material and methods: Consecutive cardiac surgery cases (n=2641) were analyzed. Patients with CVA were extracted from a database designed to monitor clinical symptoms. Patient records were used to confirm clinical data and diagnosis. Subdivision was made into three groups: control subjects, immediate, and delayed CVA, being analyzed for neurological symptoms (I). Patients with CVA who also had been investigated with computer tomography (CT) (n=77) were further evaluated in terms of hemispheric and vascular distribution of lesions. The CT-findings were compared with CVA symptoms (II). An aortic perfusion model was developed using cadaver aorta onto which multiple cross-clamp manipulations were applied (III). Washout samples of perfusate were analyzed by computerized image processing and with subdivision into different particle spectra. The model was further developed with the introduction of intraluminal manipulation from cannula and intra-aortic filter (IV). A technique for macro-anatomic mapping of plaque distribution of cadaver thoracic aorta was developed (V). Variation in plaque density was analyzed in different anatomical segments, monitored by digital image analysis. Hazards associated with surgical manipulation were studied by superimposing cannulation and cross-clamp sites onto the aortic maps in a blinded fashion. Results: The incidence of immediate and delayed CVA was 3.0% and 0.9%, respectively. Aortic quality was a strongly associated with immediate but not delayed CVA. Left-sided symptoms of immediate CVA were significantly more frequent than of the contra-lateral side. Positive signs on CT were seen in 66% of the CVA patients. Right-hemispheric lesions were more frequent compared with the contra-lateral side and the middle-cerebral artery territory dominated. Aortic cross-clamping produced a substantial output of particulate matter. Manipulation by intra-aortic filter produced a significant washout of embolic particles that escaped the filter, although some particles were captured. Cannulation was an additional source of embolic material. In terms of plaque distribution was the anterior wall of the ascending part and arch of the aorta more affected than its posterior side. However, observing a plaque in the anterior wall of this aortic segment predicted to 83% a concomitant plaque in the posterior wall. Increased age correlated positively with plaque density. The theoretical chance of interfering with a plaque during cannulation and/or clamp positioning was 45.8%. Conclusions: Both CT scans and clinical symptoms confirmed that CVA after cardiac surgery had a right-hemispheric predominance. The perfusion model resulted in a profound output of material during cross-clamp maneuvers. The intra-aortic filter successfully collected particles but also generated embolic debris on its own. Aortic cannulation was an additional source of embolic debris. Plaques were frequently found in the cadaveric aorta, and there was a high risk of plaque interference during surgical manipulation. As expected, plaque density was age-dependent.

Le niveau de risque dans l'HTA est lié en partie au niveau de pression artérielle systolique (PAS) et diastolique (PAD) mais également aux atteintes d'organes cibles infracliniques. Les objectifs de ce travail sont de rechercher des facteurs pronostiques concernant le remodelage du ventricule gauche et de l'aorte dans le cadre des pathologies cardiovasculaires. Les résultats ont été obtenus à partir de la cohorte historique OLD-HTA constituée au début des années 1970 et des patients pris en charge actuellement dans le service de cardiologie. Concernant le remodelage ventriculaire gauche, nous démontrons que l'onde R aVL sur l'ECG est corrélé à l'hypertrophie ventriculaire gauche en s'appuyant sur l'IRM cardiaque comme gold standard et qu'elle permet de prédire la mortalité toute cause et cardiovasculaire dans l'HTA. D'autre part, nos résultats permettent de mieux appréhender la valeur pronostique de la PAD qui devient un élément protecteur pour une PAS donnée en cas d'athérome aortique. Enfin, nous démontrons que la présence d'athérome aortique ou de calcifications aortiques est un élément prédicteur d'événements cardiovasculaires dans les suites d'un remplacement valvulaire aortique percutané et lorsque la fréquence cardiaque est élevée chez le patient hypertendu. L'ensemble de ces éléments pronostiques permettra à l'avenir de mieux stratifier le risque cardiovasculaire de nos patients en évaluant afin de leur proposer les thérapeutiques les plus adaptées / Risk stratification in hypertension is related to the level of systolic blood pressure (SBP) and diastolic blood pressure (DBP) but also to the presence of subclinical target organ damages. The aims of the studies conducted were to determine the prognostic values of left ventricular and aortic remodeling in the clinical setting of cardiovascular disease. Results were obtained in our historic OLD-HTA cohort started in the 70’s and with patients currently treated in our cardiology department. Regarding left ventricular remodeling, we demonstrated that R wave in aVL lead from the electrocardiogram is a robust index of left ventricular hypertrophy using cardiac MRI and this index is also a powerful predictor of all-cause and cardiovascular mortality in hypertension. Moreover, our results indicated that at a specific level of SBP, a low DBP is harmful in the presence of aortic atheroma. Therefore, aortic atherosclerosis or aortic calcifications are a major predictor of cardiovascular events after transcutaneous aortic valve implantation and in hypertensive patients with high resting heart rate. Taken together these data emphasize the interplay between aorta and the heart and provide some new hints to improve risk stratification particularly in hypertension