Correlation between Three Methods of Blood Pressure Measurement (Impedance Cardiography, Sphygmomanometry, and Invasive Methods)

Abstract

Aims and Objectives: The aims of the study were to find out the correlation between three methods of blood pressure (BP) measurement with impedance cardiography (ICG) device, conventional non-invasive sphygmomanometer, and cath lab-based invasive arterial pressure (AP) study.
Patients Materials and Methods: Patients who had definite indications for coronary angiography (CAG) or coronary intervention due to cardiac reasons were selected for the measurement of BP by three methods, namely, by transducer-based invasive central aortic pressure study, by ICG, and by conventional sphygmomanometry. One hundred patients of acute myocardial infarction having chest pain, ST elevation in two or more contiguous leads of electrocardiogram (ECG), biomarker positivity, and echocardiographic evidence of regional wall motion abnormality were selected. Transfemoral or radial access of the ascending aorta allowed the measurement of central aortic pressure during invasive procedure. CAG was done in the cath lab having “Siemens™ Axiom Artis Zee (floor)” equipment. The subjects who were unwilling to participate, who were moribund, critically ill subjects, and patients with concomitant heart failure, arrhythmia, and valvular lesions were excluded from the study. GE™ Vivid 7 Dimension machine was used for ECG-gated echo-Doppler studies. ICG-derived BP values (systolic BP [SBP], diastolic BP [DBP], mean AP [MAP], and pulse pressure) were recorded for comparison with similar pressure data obtained from two other methods.
Results and Analysis: Analysis of results show a comparison of data on SBP, DBP, and MAP measured by three methods by sphygmomanometry, invasive, and ICG methods. The analysis also shows the values of correlation coefficients – all of which are significantly positive correlations. ICG has been found to have positive correlation with both sphygmomanometric and invasive methods of BP measurement. It also shows a graphical presentation of the correlation between SBP, DBP, and MAP measured by three methods by sphygmomanometry, invasive, and ICG methods.
Conclusion: There is a significant correlation between three methods of BP measurement with ICG device, conventional non-invasive sphygmomanometer-based method, and cath lab-based invasive AP study.