Measuring Variation of IVC Diameter in Bangladeshi Population in BIRDEM – A Prospective Observational Study

Background: Echocardiographic assessment of inferior vena cava (IVC) diameter and its respiratory variation helps to measure right atrial pressure (RAP). While IVC distends RAP rises. Phases of respiratory cycle has significant variation of inferior vena cava diameter in normal individual. There may be other factors that also influence IVC diameter. Aim: The present study aimed to see the size and dynamics of IVC, its respiratory variation and other factors influencing IVC diameter.. Methods & Materials: This prospective observational study was conducted at BIRDEM over six months in 2024, involving 1200 adult patients. Demographic data were recorded. BMI was calculated and categorized for analysis. Echocardiographic assessments of IVC maximum (IVC Max) and minimum (IVC Min) diameters, collapsibility index (CI), left ventricular ejection fraction (EF), and diastolic dysfunction (DD) were measured. Variation of IVC diameter with age, sex, BMI, EF, DD, and DM were assessed, with p < 0.05 considered significant. Results: The mean age of participants was 53.04 ± 10.95 years, and mean BMI was 26.00 ± 4.46 kg/m². Mean IVC Max and Min diameters were 18.44 ± 1.84 mm and 13.28 ± 2.00 mm, with a mean CI of 0.292 ± 0.115. IVC size correlated positively with age, male sex, and BMI (p < 0.01) but not with diabetes (p > 0.05). Larger IVC diameters and lower CI were observed in participants with reduced EF and advanced diastolic dysfunction (p < 0.001). Conclusion: IVC diameter and collapsibility index are significantly related to cardiac function and demographic factors, serving as useful non-invasive indicators of right atrial pressure and cardiac filling status.