Improvement Of Blood Pressure Measurement In Atrial Fibrillation

Blood pressure(BP)is one of the most important physiological parameters of the body, which is the most important indicator as the state of the hemodynamic response, and appropriate blood pressure is the basic of maintaining normal blood circulation. Too much high blood pressure will cause serious damage to the body. Immediately and effectively intervention of BP can avoid serious consequences. Therefore, it is a great significance to accurately measure blood pressure for the diagnosis and treatment of the body condition and clinical disease.Blood pressure measurements include direct and indirect measurement and indirect pressure called as non-invasive measurement of blood pressure. Auscultatory Korotkoff sound method and oscillometric method are the most extensive blood pressure measurement method in clinical application. The most commonly used oscillometric method is adopted by using “calculation of blood pressure” approach. Any mechanical and electromagnetic interference will affect the image of oscillatory wave, and calculated by the formula and can not be completely ruled out the mixed signal, so the environmental factors have influenced on blood pressure measurements.It is very common that patients with essential hypertension complicated with atrial fibrillation(AF) and hypertension increased thrombotic events incidence in AF patients, especially the incidence of stroke. blood pressure management of AF patients with hypertension is a very important issue, so far the accuracy of noninvasive blood pressure measurement in atrial fibrillation(AF) has been strongly questioned. Therefore, to improve the blood pressure measurement accuracy in AF patients is an important target. Based on these issues, this study is divided into three parts.The First Part The value of a BP determination method using a novel non-invasive BP device against the invasive catheter measurementObjective: The aim of this study was to evaluate the accuracy of a new blood pressure(BP) measurement method(Pulse method).Methods: This study enrolled 45 patients for selective percutaneous coronary intervention(PCI) via right radial artery. A BP device using either oscillometric(Microlife 3AC1-1) or Pulse method(RG-BP11)was used. At the beginning of each PCI, intra-radial BP was measured before Microlife BP or Pulse BP measurement as its own reference, respectively. At the end of PCI, BP was measured again with the measurement order of Microlife BP and Pulse BP reversed. The differences between intra-radial and Microlife(BPi-M) or Pulse BP(BPi-P) on SBP, DBP and mean artery pressure(MAP) were calculated. Meanwhile, in 48 patients the intra-brachial BP and intra-radial artery BP were measured to calculate the brachial-radial BP difference(BPr-b).Results: The intra-radial SBP referred by Microlife SBP was similar to that by Pulse SBP(145.1±27.7 vs 145.8±24.2 mm Hg), but the Microlife SBP was significantly lower than the Pulse SBP(127.7±20.5 vs 130.3±22.7 mm Hg, P<0.05), thus the SBPi-M was higher than SBPi-P(18.1±11.8 vs 14.8±12.8 mm Hg, P<0.05). As the mean SBPr-b was 12.4 mm Hg, the Pulse SBP was closer to expected intrabrachial SBP by about 3.3mm Hg than was Microlife SBP to expected intra-brachial SBP. Meanwhile, Bland-Altman plots showed that the 95% limits of agreement for intra-radial SBP by Pulse SBP were narrower than those by Microlife SBP(12.0~17.5 vs 15.5~20.6 mm Hg). However, the 95% limits of agreement for Pulse DBP and MAP were similar to those for Microlife DBP and MAP.Conclusion: Against the invasive BP measurement, the pulse method may provide more accurate SBP and comparable DBP and MAP as compared with the oscillometric method.The Second Part Better accuracy and reliability of a new automatic BP device on pulse wave as comparison with a current oscillometric deviceObjective: This study was to identify the accuracy and reliability of a new automatic blood pressure(BP) devise in patients with sinus rhythm(SN) or atrial fibrillation(AF)Method: This study included 40 subjects with SN and 40 patients with AF aged from 22 to 83 years old. Three devices, manual mercury auscultatory(MA), automatic oscillometric(AO)and automatic pulse wave(APW, RG-BP11, Shenzhen Ruiguang Kangtai co.) were used to measure BP of each subject for 2 times with 2min interval. One doctor was responsive to automatic BP and the other for auscultatory BP measurement. The route 1 for the use of sphygmomanometer was: AO-MA-APW- APW – MA- AO; and the route 2 was: APW-MA-AOAO-MA-APW. The use of route 1 and route 2 was crossover, and each subject had 6 BP measurements. The average of 2 BP values from one device was recorded as the final values, respectively. The difference between the BP from APW or AO with BP from MA was calculated as BP-P-M and BP-O-M. Meanwhile, the difference within the 2 BP values from AO or APW methods was calculated as BP-OO and BP-PP.Results: In the subjects with SN, the SBPs from MA, AO and APW were similar(133.8±15.6 and 132.3±15.6 vs 134.4±17.6 mm Hg, NS). The DBP from APW was similar to that from MA(76.8 ± 13.5 vs 76.8 ± 13.0mm Hg, P<0.05), but the DBP from AO was significantly lower than that form MA(70.6 ± 10.5mm Hg). In the patients with AF, SBP from APW and AO were significantly lower than that from MA(123.4 ± 24.2 and 122.2 ± 21.8 vs 127 ± 22, both P <0.05), although SBP from APW was closer to SBP from MA. The DBPs from APW or AO were significantly lower than that from MA(70.3 ± 14.8 and 68 ± 10.3 vs 72.2 ± 11.9mm Hg, P<0.05), but DBP from APW was closer to DBP from MA.BP-AO-AO and BP-APW-APW. The correlation coefficient for systolic blood pressure was 0.88 and for diastolic 0.79. Differences between auscultatory and oscillometric values were less than 10 mm Hg in 70.6% of systolic blood pressures and in 83.2% for diastolic. Arrhythmia and hypertension did not influence the results, and there was no correlation between the magnitude of the differences and the level of blood pressure.Conclusion:The blood pressure value of automatic pulse wave is not accurate than automatic oscillometric.The Third Part How to evaluate BP measurements using the oscillometric method in atrial fibrillation: the value of pulse rate variationObjective: An oscillometric device is recommended for blood pressure(BP) measurement in atrial fibrillation(AF), but there is still controversy concerning its accuracy. Therefore, evaluation of BP values in AF patients remains a challenge.Methods: This study included 251 patients with AF and 154 participants with sinus rhythm(SR). Pulse rate(PR) and BP were measured using an oscillometric device three times. The differences between the highest and lowest values of PR, systolic and diastolic BP(SBP and DBP) were calculated as △PR, △SBP and △DBP, respectively. AF patients were stratified with respect to △PR in 0-5, 6-10, 11-15 and >15 subgroups.Results: The AF group had a greater ΔPR(12.1±8.6 vs. 4.10±3.21 bpm, P<0.001), ΔSBP and ΔDBP than the SR group at similar SBP and DBP. A positive correlation existed between ΔPR and ΔSBP(r=0.255, P<0.001) in AF patients, but no correlation was found in SR subjects. Meanwhile, the ΔSBP in the 0-5 and 6-10 subgroups(9.58±5.61 and 10.67±6.77 vs. 8.45±5.25 mm Hg, NS) was similar to the SR group, whereas ΔSBP in the 11-15 and >15 subgroups was significantly greater than the SR group. Regardless of △PR, the ΔDBP in the AF group was significantly greater than that of the SR group.Conclusion: The AF patients who exhibited greater variability in their pulse rate also had a greater variability in their SBP readings. The SBP measurement for AF patients is accurate as the measurement for patients with sinus rhythm if the ΔPR is of 0-10 bpm in AF.