The availability of simple, accurate, and affordable cuffless blood pressure (BP) devices has the potential to greatly increase the compliance with measurement recommendations and the utilization of BP measurements for BP telemonitoring. The aim of this study is to evaluate the correlation between findings from routine BP measurements using a conventional sphygmomanometer with the results from a portable ECG monitor combined with photoplethysmography (PPG) for pulse wave registration in patients with arterial hypertension. Methods: The study included 500 patients aged 32–88 years (mean 64 ± 7.9 years). Mean values from three routine BP measurements by a sphygmomanometer with cuff were selected for comparison; within one minute after the last measurement, an electrocardiogram (ECG) was recorded for 3 min in the standard lead I using a smartphone-case based single-channel ECG monitor (CardioQVARK®-limited responsibility company “L-CARD”, Moscow, Russia) simultaneously with a PPG pulse wave recording. Using a combination of the heart signal with the PPG, levels of systolic and diastolic BP were determined based on machine learning using a previously developed and validated algorithm and were compared with sphygmomanometer results. Results: According to the Bland–Altman analysis, SD for systolic BP was 3.63, and bias was 0.32 for systolic BP. SD was 2.95 and bias was 0.61 for diastolic BP. The correlation between the results from the sphygmomanometer and the cuffless method was 0.89 (p = 0.001) for systolic and 0.87 (p = 0.002) for diastolic BP. Conclusion: Blood pressure measurements on a smartphone-case without a cuff are encouraging. However, further research is needed to improve the accuracy and reliability of clinical use in the majority of patients.

ель исследования. Сравнить диагностическую эффективность мультиспиральной компьютерной томографии коронарных артерий (МСКТ КА) и стандартного теста с физической нагрузкой в качестве методов первой линии для диагностики стабильной ишемической болезни сердца в амбулаторных условиях. Материалы и методы. В исследование проспективно включены 74 пациента с типичной и атипичной ангинозной симптоматикой продолжительностью более 3 недель, средний возраст-63,9±10,4 года, 28 (37,8%) женщин. Критерии исключения: противопоказания к применению йодсодержащих контрастных веществ, статинов; СКФ <45мл/мин/1,73 кв.м; невозможность выполнить нагрузочный тест. Всем пациентам последовательно выполнены нагрузочный тест (стандартный и модифицированный протокол Брюса), МСКТ КА на компьютерном томографе Aquilion ONE 640 с внутривенным контрастированием (контрастный препарат «Ультравист-370»), по стандартному протоколу. Определена предтестовая вероятность ИБС, произведена стратификация риска по шкале SCORE и ACC/AHA. Статистическая обработка выполнена на программном обеспечении SPSS 11.5. Результаты. Результаты тредмил-теста были положительными в 51,4%, из них по данным МСКТ КА в 19,15% были выявлены стенозы ≥ 70%, в 35,3%-стенозы 50-69%. У 28,6% мужчин и 46,2% женщин с типичной и 66,7% мужчин и 50,0% женщин с атипичной ангинозной симптоматикой, имеющих положительный результат тредмилтеста, по данным МСКТ КА не было выявлено признаков атеросклеротического поражения. У 4,05% пациентов с отрицательным результатом нагрузочного теста были выявлены признаки значимого поражения артерий (стеноз >70%). По шкале SCORE у пациентов, имеющих атеросклеротические изменения коронарных артерий, высокий риск наблюдался у 67,6%, по шкале ACC/AHA-у 70,6%. Чувствительность и специфичность шкал SCORE и ACC/AHA в выявлении атеросклероза коронарных артерий составили 83% и 71% и 81% и 88% соответственно (p> 0.05). Заключение. МСКТ КА может рассматриваться в качестве метода первичной диагностики стабильной ИБС в амбулаторной практике. Ключевые слова: компьютерная томография, стресс-тест, предтестовая вероятность, оценка риска, атеросклероз, ишемическая болезнь сердца.

Aim. Comparative analysis of the diagnostic effectiveness of onedimensional (1-D) and three-dimensional (3-D) non-invasive methods for coronary fractional flow reserve (FFR) assessment based on the coronary computed tomography angiography (CCTA). Material and methods. We carried out a retrospective analysis of CCTA data for 13 patients (men -9, mean age -61,07±9,73). In the original research, coronary FFR of those patients was evaluated using the original 3-D HeartFlow ® Analysis followed by a standard invasive FFR assessment. We estimated coronary FFR using the 1-D algorithm of the Laboratory of Mathematical Modeling (Sechenov University) and compared the diagnostic effectiveness of these methods. Results. In per-vessel analysis, the sensitivity and specificity of the 3-D approach were 90,91% (95% confidence interval (CI) 62,26-99,53) and 20% (95% CI 0,01026-62,46, p>0,9999), respectively; in perpatient analysis -90% (95% CI 59,58-99,49) and 0% (95% CI 0-56,15, p>0,9999), respectively; area under the ROC curve was 93,75% (95% CI 80,26-100), p=2,0431 e-10 . For the 1-D approach, the same parameters in per-patient analysis were 88,89 % (95% CI 56,50-99,43) and 25% (95% CI 0,01282-69,94, p>0,9999), respectively; in per-vessel analysis -100% (95% CI 72,25-100) and 33,33% (95% CI 0,05923-70, p=0,1250), respectively; area under the ROC curve was 84,54% (95% CI 63,93-100), p=0,001. Spearman's rank correlation coefficient between the 3-D and 1-D techniques was 0,7326 (95% CI 0,3581-0,9041), p=0,0017. Conclusion. Although we have obtained lower values of area under the ROC curve, the sensitivity and specificity of experimental approach, as well as the correlation coefficient between models were rather high. However, further studies with higher statistical power are required. Key words: one-dimensional model of coronary blood flow, threedimensional model of coronary blood flow, non-invasive fractional flow reserve, coronary artery disease, computed tomography.

The aim. To evaluate the reliability of blood pressure (BP) measurement results using a cuffless blood pressure device (CardioQVARK®) in comparison with the values obtained using the Korotkov method.Materials and methods. An observational cross-sectional study of 50 patients (25 men, mean age 60 ± 14 years) with arterial hypertension was performed. Blood pressure was measured by the Korotkov method as a standard method, and a CardioQVARK® device, made in the form of a smartphone case, was used as a new method. The device records the electrocardiogram and the photoplethysmogram. Based on the parameters of the electrocardiogram and the photoplethysmogram the systolic and diastolic blood pressure (SBP and DBP) is calculated. Correlation analysis, Student’s t-test, Bland-Altman method were used for comparing the two methods, the standard deviation of the difference and a 95% confidence interval (95% CI) were calculated.Results. There were no statistically significant differences in the mean values of SBP and DBP for the two methods. There was a strong direct relationship between SBP (r = 0.976, p < 0.0001) and DBP (r = 0.817, p < 0.0001), measured by two methods. Bias for SBP and DBP measured by the new method was: –0.5 mm Hg (95% CI: –1.7; 0.7) and –0.3 mmHg (95% CI: –1.4; 0.7), respectively. The difference in DBP measurements depended on the blood pressure level (r = 0.302, p = 0.03). The underestimation of DBP values was more pronounced for low blood pressure from 55 to 75 mm Hg. At the time of the study, 13 (26%) patients had an increase in blood pressure. The sensitivity of the new method in detecting arterial hypertension was 77% (95% CI: 46; 95), specificity 100% (95% CI: 91; 100), accuracy 94% (95% CI: 83; 99).Conclusion. The blood pressure measurement method based on the analysis of the electrocardiogram and photoplethysmogram showed reliable blood pressure measurement results in comparison with the Korotkov method.

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