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Noninvasive measurements of blood pressure (BP) and cardiac output (CO) are crucial in the follow-up of continuous-flow left ventricular assist device (CF-LVAD) patients. For our pilot study, we sought to compare BP measurements between a tonometry blood pressure pulse analyzer (BPPA) (DMP-Life, DAEYOMEDI Co., Ltd., Gyeonggi-do, South Korea) and Doppler ultrasound in CF-LVAD patients, as well as to compare the BPPA estimated CO to LVAD calculated blood flow and to the patient's intrinsic CO estimated with transthoracic echocardiography (TTE). Ambulatory CF-LVAD patients (6 HeartMate, 26 HeartMate II), were included. According to TTE findings, patients were then subdivided in two groups: patients with an opening aortic valve (OAV) [n = 21] and those with an intermittent opening aortic valve (IOAV) [n = 11]. We found a very good correlation of systolic BP (SBP) measurements between the two methods, BPPA and Doppler ultrasound (r = 0.87, P < 0.0001). Bland-Altman plots for SBP revealed a low bias of -4.6 mm Hg and SD of ±4.7 mm Hg. In CF-LVAD patients with IOAV, the BPPA-CO had a good correlation with the LVAD-flow (r = 0.78, P < 0.0001), but in OAV patients, there was no correlation. After adding the patient's intrinsic CO, estimated from TTE in patients with OAV to the LVAD-flow, we found a very good correlation between the BPPA-CO and LVAD-flow + TTE-CO (r = 0.81, P = 0.002). Our study demonstrated that compared with the standard clinical method, Doppler ultrasound, the BPPA measured BP noninvasively with good accuracy and precision of agreement. In addition, tonometry BPPA provided further valuable information regarding the CF-LVAD patient's intrinsic CO., (© 2018 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.)

Parameters for noninvasive diagnosis and monitoring of cardiovascular disease. We developed a new method to measure blood pressure (BP) noninvasively without cuff. In Korean traditional medicine, the degree of the pulse depth is one of the important criteria to diagnosis. We combined this concept with pulse wave analysis. With clinical data obtained from 163 subjects, we selected APm (applied pressure which has a maximum value of pulse wave), elasticity of wrist tissue, depth of blood vessel, cardiac output and h1 as parameters to estimate blood pressure. And with the parameters, we induced multi regression equation of systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP) and pulse pressure (PP). And the probabilities of these parameters to explain SBP, DBP, and MAP were 89.5%, 91.1% and 94.6%, respectively. To estimate PP, we added h1 to the parameters to explain PP was 97.5%. We compared the estimated SBP, DBP, MAP and PP through the multiple regression equations to the actual measured SBP, DBP, MAP and PP through the wrist type BP meter. Differences were (+/- SD) 0.38 +/- 9.95, -1.0 +/- 8.2, 0.02 +/- 6.9 and 0.05 +/- 5.9mmHg for SBP, DBP, MAP and PP, respectively. According to the American National Standard for Electronic or Automated Sphygmomanometers, the mean difference (MD) should be +/- 5mmHg or less with a standard deviation (SD) of +/- 8mmHg or less. Hence, the results of MAP and PP were within the limits for the AAMI SP 10 criteria and the results of SBP and DBP were not within the limits for the AAMI SP 10 criteria. The preliminary results indicate the results are quite reliable and promising.

We developed a cuffless and noninvasive measurement technique of blood pressure using tonometric pressure sensor. With observation that the maximum value of a pulse pressure is not obtained at mean arterial pressure (MAP), we have figured out MAP based on the physiological characteristic including the elasticity of wrist tissue, the depth of blood vessel. Through an analysis of 198 clinic data, we have induced the regression equation of the MAP. The probability of the elasticity, depth and AP(M) to explain MAP was 92.1%. The mean difference and the standard deviation between the MAP predicted from the regression equation and the MAP measured by commercial cuff type BP meter were Z-3.183 mmHg and 5.133 mmHg respectively. Comparing the results with the American national standard for electronic or automated sphygmomanometers, we can conclude that the results are quite reliable and promising. Detecting only one part of the body and using only one device are quite advantageous over other BP measurement technique. Our technique makes new way for the cuffless BP measurement.