Assessment of hemodynamic parameters

Hemodynamics was quantified as cardiac index (CI, L/min/m²), systemic vascular resistance index (SVRI, dynes/sec/cm⁵/m²) and stroke index (SI, mL/m²). Cardiovascular examinations were performed in temperature-controlled rooms after the acclimatization of the participants in the study centers. Pulsatile, resistive and flow-related hemodynamics were obtained beat-to-beat in the supine position after 5 min of rest with an impedance cardiography device, which registers simultaneously electrocardiography (ECG) signals and measures blood pressure at 2-min intervals. Briefly, cardiac output (CO, L/min) was computed as stroke volume (SV, mL) multiplied by heart rate (beat per minute). CI was computed as CO divided by body surface area (BSA, m²). SVRI was calculated as mean arterial pressure (MAP, mmHg) divided by CO, multiplied by 80. SI was computed as SV divided by BSA.