Aortic or Mitral Valve Replacement With the Braile Biomédica® Bovine Pericardium Valvular Bioprosthesis

Inclusion Criteria: (Group I - Aortic): * Symptomatic patients with severe aortic insufficiency. * Asymptomatic patients with severe aortic insufficiency and left ventricular ejection fraction (LVEF) at rest ≤ 50%. * Patients with severe aortic insufficiency and undergoing coronary artery bypass graft surgery (CABG) or surgery of the ascending aorta or other valve. * Asymptomatic patients with severe aortic insufficiency and resting ejection fraction \> 50% with severe left ventricular (LV) dilation: left ventricular end-diastolic diameter (LVDD) \> 70 mm or left ventricular ejection fraction (LVEF) \> 50 mm (or LVEF \> 25 mm/m2 of body surface, in patients with small body size). * Symptomatic patients with severe high gradient aortic stenosis (mean gradient ≥ 40 mmHg or peak velocity ≥ 4.0 m/s). * Symptomatic patients with severe low-flow, low-gradient aortic stenosis (\< 40 mmHg) with reduced ejection fraction and evidence of flow reserve (contractile) excluding pseudo-severe aortic stenosis. * Symptomatic patients with low-flow, low-gradient (\< 40 mmHg) aortic stenosis with normal ejection fraction after careful confirmation of severe aortic stenosis. * Symptomatic patients with low-flow, low-gradient aortic stenosis and reduced ejection fraction without flow reserve (contractile), particularly when the amount of calcium on computed tomography (CT) confirms severe aortic stenosis. * Patients with symptomatic aortic stenosis at low surgical risk (STS or EuroSCORE II \< 4% or logistic EuroSCORE I \< 10% and no other risk factors not included in these scores, such as fragility, porcelain aorta, sequelae of thoracic radiation). * Asymptomatic patients with severe aortic stenosis and LV systolic dysfunction (LVEF \< 50%) not due to another cause. * Asymptomatic patients with severe aortic stenosis and an abnormal exercise test showing exercise symptoms clearly related to aortic stenosis. * Asymptomatic patients with severe aortic stenosis and an abnormal exercise test showing a decrease in blood pressure below baseline. * Asymptomatic patients with normal ejection fraction and no exercise stress test abnormality, if the surgical risk is low and have very severe aortic stenosis defined by a peak transvalvular velocity (Vmax) \> 5.5 m/s. * Asymptomatic patients with normal ejection fraction and no exercise test abnormality, if the surgical risk is low and severe valve calcification and Vmax progression rate ≥ 0.3 m/s/year. * Asymptomatic patients with normal ejection fraction and no exercise stress test abnormality, if surgical risk is low and B-type natriuretic peptide (BNP) marker levels are high. * Asymptomatic patients with normal ejection fraction and no change in the exercise test, if the surgical risk is low and severe pulmonary hypertension (pulmonary artery systolic arterial pressure at rest \> 60 mmHg confirmed by invasive measurement) with no other explanation. * Patients with severe aortic stenosis undergoing CABG or surgery of the ascending aorta or other valve. * Patients with moderate aortic stenosis undergoing CABG or surgery of the ascending aorta or other valve after decision by the Heart Team. 7.2. Inclusion Criteria (Group II - Mitral): * Symptomatic patients with severe primary mitral insufficiency and LVEF \> 30%. * Asymptomatic patients with severe primary mitral insufficiency and LV dysfunction (LVEF \> 45 mm and/or LVEF \< 60%). * Asymptomatic patients with severe primary mitral regurgitation and preserved LV function (LVEF \< 45 mm and LVEF \> 60%) and atrial fibrillation secondary to mitral regurgitation or pulmonary hypertension (rest systolic pulmonary pressure \> 50 mmHg). * Asymptomatic patients with severe primary mitral regurgitation and preserved LVEF (\> 60%) and LVEF 40-44 mm, with leaflet failure. * Asymptomatic patients with severe primary mitral regurgitation and preserved LVEF (\> 60%) and LVEF 40-44 mm, and presence of significant LA dilation (volume index ≥ 60 mL/m2 of body surface) in sinus rhythm. * Patients with severe primary mitral regurgitation and severe LV dysfunction (LVEF \< 30% and/or LVEF \> 55 mm) refractory to medical therapy. * Patients with severe chronic secondary mitral regurgitation undergoing CABG and LVEF \> 30%. * Symptomatic patients with severe secondary mitral regurgitation, LVEF \< 30%, but with the option of revascularization and evidence of myocardial viability. * Patients with severe secondary mitral regurgitation and LVEF \> 30% who remain symptomatic despite optimal clinical treatment and with low surgical risk. * Symptomatic patients with mitral stenosis (valve area ≤ 1.5 cm2) who are not suitable for percutaneous mitral commissurotomy. Exclusion Criteria: * Emergency surgical valve replacement. * Surgical replacement of the aortic root. * Patients who did not return for follow-up examinations. * Patients with renal impairment as determined by creatinine level ≥ 2.5 mg/dL or end-stage renal disease requiring chronic dialysis. * Patients with stroke or transient ischemic attack within 6 months (180 days) before planned valve surgery. * Patients with acute myocardial infarction within 30 days before planned valve surgery. * Patients with any known life-threatening non-cardiac disease that will limit the patient's life expectancy below 1 year. * Patients diagnosed with abnormal calcium metabolism and hyperparathyroidism. * LVEF ≤ 20%, as validated by the diagnostic procedure before planned valve surgery. * Echocardiographic evidence of intra-cardiac mass, thrombus or vegetation. * Hemodynamic or respiratory instability requiring inotropic support, mechanical circulatory support, or mechanical ventilation within 30 days prior to planned valve surgery. * Documented leukopenia (leukocytes \< 3.5x10³/μL), acute anemia (Hgb \< 10.0 gm/dL or 6 mmol/L) or thrombocytopenia (platelet count \< 50x10³/μL) accompanied by a history of bleeding diathesis and coagulopathy. * Patients who underwent organ transplantation. * Pregnant or breastfeeding. * Patients with a documented history of substance abuse (drugs or alcohol) in the last year before implantation. * Concomitant positioning of the left ventricular assist device.