A Collective Study performed on Asian Chinese Normotensive Population to Obtain Healthy Normal Range of some Waveform Indices
Background- Arterial blood pressure waveforms contain rich pathophysiological information of the cardiovascular system where they are more than just numerical digits of indices. This information includes indices describing left ventricular systolic function and arterial properties such as the conventional systolic blood pressure (SBP), diastolic blood pressure (DBP) and pulse rate (PR) which have been validated with a set of range as a guide to aid monitoring of the blood pressure. Fiducial points of arterial blood pressure waveforms such as the onsets, systolic peaks and dicrotic notches are important points of the arterial blood pressure waveform and such information would serve as a better reflect one's health condition. Thus with these information, a new set of additional indices such as central aortic systolic pressure (CASP), systolic upstroke gradient (SUG), systolic cycle and ratio of net area (RNA) may serve a basis of assessment of one's health.
Methods and Results- We conducted a study using BPro®, a validated US FDA (510k no.: k060315) approved device, which is connected to a laptop with an A-PULSE CASP software that has been clinical validated and approved by the regulatory authorities, US FDA (510k no. : k072593). A total of 2157 Asian subjects comprising of 1036 females and 1121 males participated in this study. The subjects were drawn from Singapore and China provinces such as Beijing, Shanghai and Xi An. With the collected data, simple scatter plots of the distribution of the various indices for normotensive people were drawn across the age group. After which, linear equations were determined using linear regression analysis and 95% confidence interval denoting the reference range for normotensive population for the various indices. These graphs were plotted using SPSS 13.0 and Microsoft Office Excel 2003.
Conclusions- The ability to express waveform indices in terms of numbers not only aid in the determination of the effects of drugs and other interventions, reference ranges and trends have been generated to monitor and aid in improving the quality of our health. Through this study, we highlight CASP, SUG, systolic cycle and RNA with brief analysis and their reference ranges. Currently, there has already been a shift to include CASP measurements and reference ranges in a few guidelines for hypertension. Hence, it is hoped that more outcome studies and trials may be conducted to seek greater relevance and correlations of these waveform indices to our health. Therefore in future, we seek to attach weightage to these waveform indices to generate a composite index. And with this impactful composite index comprising of all the important indices, we are able to obtain a more accurate indicator of our cardiac health.