PREVASC is a cross-sectional, population-based study. Participating subjects are invited from the general population and underwent a physical examination and an electrocardiography and echocardiographic examination by a local cardiologist. A random sample of about 2000 subjects over 65 years will be considered for sampling. The sample size is determined on the basis of a priori criteria in order to estimate a prevalence of 3% [standard error (SE) ± 1.1] for VHD.
Both clinical and demographic information will be collected to better characterize the invited population. Written informed consent for the clinical examination will be asked.
Demographic variables, cardiovascular (CV) risk, clinical history, physical findings, and medications will be recorded in a Case Report Form (CRF) by physicians or trained nurses. Assessment of anthropometric measures, blood pressure, and heart rate will be performed according to MONICA recommendations. Overweight is defined as a body mass index (BMI) between 25 and 29.9 kg/m2. Obesity is defined as BMI ≥30 kg/m2. Symptoms and signs attributable to VHD will be evaluated and reported on the CRF by a dedicated expert physician in each site at the time of the physical examination.
Echocardiography Complete Colour Doppler echocardiography will be performed in peripheral centers using commercially available machines according to a pre-defined protocol. Echocardiograms will be recorded in standard DICOM format on digital.
The following parameters will be acquired:
- Linear measurements of cardiac chambers will be obtained from the two-dimensional (2D) parasternal long axis view or, when available, from the M-mode parasternal short axis recording according to the recommendations of the European American Society of Echocardiography and the European Association of Cardiovascular Imaging [].
- LV volumes will be obtained from the apical four-chamber view and the EF calculated by using the modified Simpson's rule method.
- Left ventricular mass will be calculated according to the Devereux formula.
- Left ventricular systolic function will be calculated using the formula for ejection fraction EF: EDV-ESV/EDV X100.
- Also left atrium area or volume will be measured by the 4-chamber view.
- Calcifications of the aortic valve and mitral apparatus will be quantified as light, moderate, or severe, according to a published approach. The bicuspid aortic valve will be searched for and recorded. Trans-aortic and trans-mitral gradients, as well as mitral, aortic, and tricuspid regurgitation, will be reported and quantified according to continuous wave Doppler and Color Doppler area of regurgitation or vena contracta (VC) width (light, moderate, severe), respectively. For quantitative measurement of mitral regurgitation and tricuspidal regurgitation PISA method will be used. For aortic regurgitation PHT will be adopted other than VC. The aortic valve area will be calculated using the continuity equation other than the planimetric area. Mitral valve area will be calculated using pressure half time (PHT) other than planimetric area. Pulmonary artery systolic pressure will be estimated according to standard method.
- Doppler-derived indexes of transmitral flow and pulmonary vein flow, and tissue Doppler imaging of the lateral mitral annulus (E/e') will be used to define diastolic LVD. Peak early diastolic filling wave (E) velocity, peak atrial diastolic filling wave (A) velocity, and deceleration time of the E wave (DTE) will be measured at the tips of the mitral leaflets. The DTE will be calculated as the time from E to the time when the descent of E intercepts the zero line. The duration of the transmitral A wave velocity will also be measured. The peak velocity of pulmonary venous (PV) systolic (S), and diastolic (D) flow, the peak velocity of PV backward flow at atrial contraction (PVa), and the PVa wave duration (PVa dur) will be measured with the sample volume placed in the right upper pulmonary vein in the four-chamber axis view. The difference between the transmitral A wave duration (Adur) and PVa dur will be derived as an indirect index of increased LV filling pressures, according to the standard method. Tissue Doppler will be used to calculate the E/e' ratio.
- All digital echocardiograms will be analyzed offline on a dedicated workstation by three independent observers, blind to clinical data, and reviewed by the same experienced reader. Measurements will be expressed as an average of three cycles in sinus rhythm and from three to five cycles in atrial fibrillation.
Cardiologists and nurses will be trained locally according to standardized methodologies. Before enrolment begins, all participating centers will be required to perform and send an echo test to the Core Lab to verify the appropriateness of the acquisition procedure.