Non-invasive Assessment Of Elevated Left Ventricular End Diastolic Pressure Using A Small Portable Device: Design For Tele-Monitoring

Abstract

Background Left ventricular end-diastolic pressure (LVEDP) provides crucial information on the LV operating compliance and is a key marker for congestive heart failure and pulmonary hypertension. The diagnosis and monitoring of the left-sided filling pressure often requiring invasive procedures. HEMOTAG, is a small portable device that uses micro-sensors to capture cardiac vibrations and electrocardiogram (ECG), transduced via thoracic electrodes. It is a viable option to measure cardiac time intervals (CTIs), surrogate markers of hemodynamics and intracardiac pressure. In this study, diastolic-to-systolic time ratio (DSR) and systolic time ratio (STR) along with the patient's age, height, and weight were assessed as valid markers for elevated LVEDP, compared against left heart catheterization LVEDP measurement. Methods In 44 female and 49 male patients, mean LVEDP was measured during cardiac catheterization. Simultaneously, Hemotag generated CTIs: systolic time (ST): mitral valve closure (MVC) to aortic valve closure (AVC), diastolic time (DT): AVC to MVC, STR: Aortic valve opening/(Aortic valve opening to Aortic valve closing), and DSR: DT/ST. The predictability value of non-invasively HEMOTAG-derived CTI ratios - diastolic time normalize by heart rate (DT/HR), DSR, and STR - plus biological information of age, height, and weight were assessed to determine elevated LVEDP (> 15 mmHg). Logistic regression analysis between the markers and LVEDP was performed. Sensitivity, specificity, correlation, and p-values were calculated. Results Mean age for the female (male) patients was 69.41 ± 11.84 (63.12 ± 10.80) and mean LVEDP was 17.20 ± 6.17 (16.57 ± 5.42). Using logistic regression with DSR, STR, age, height, and weight as features, sensitivity of 88.00%, specificity of 94.74%, AUC of 0.94, r = 0.74, p-value = 4.31e-06, were obtained for female patients; using DT/HR, STR, age, height, and weight, a sensitivity of 89.29%, specificity of 71.43%, AUC of 0.79, r = 0.40, and p-value = 0.0419 were obtained in the male patients. Conclusions HEMOTAG detected elevated LVEDP with high sensitivity and high specificity for both female and male patients. This preliminary study has demonstrated the feasibility of estimating LVEDP using a portable, non-invasive device that empowers patients to transmit such data from home instantaneously to providers. Further studies are required to validate HEMOTAG as a point-of-care non-invasive assessment for heart failure and pulmonary hypertension patients. HEMOTAG® development and the clinical study is supported by NIMHD SBIR grant # R44MD009556. Left ventricular end-diastolic pressure (LVEDP) provides crucial information on the LV operating compliance and is a key marker for congestive heart failure and pulmonary hypertension. The diagnosis and monitoring of the left-sided filling pressure often requiring invasive procedures. HEMOTAG, is a small portable device that uses micro-sensors to capture cardiac vibrations and electrocardiogram (ECG), transduced via thoracic electrodes. It is a viable option to measure cardiac time intervals (CTIs), surrogate markers of hemodynamics and intracardiac pressure. In this study, diastolic-to-systolic time ratio (DSR) and systolic time ratio (STR) along with the patient's age, height, and weight were assessed as valid markers for elevated LVEDP, compared against left heart catheterization LVEDP measurement. In 44 female and 49 male patients, mean LVEDP was measured during cardiac catheterization. Simultaneously, Hemotag generated CTIs: systolic time (ST): mitral valve closure (MVC) to aortic valve closure (AVC), diastolic time (DT): AVC to MVC, STR: Aortic valve opening/(Aortic valve opening to Aortic valve closing), and DSR: DT/ST. The predictability value of non-invasively HEMOTAG-derived CTI ratios - diastolic time normalize by heart rate (DT/HR), DSR, and STR - plus biological information of age, height, and weight were assessed to determine elevated LVEDP (> 15 mmHg). Logistic regression analysis between the markers and LVEDP was performed. Sensitivity, specificity, correlation, and p-values were calculated. Mean age for the female (male) patients was 69.41 ± 11.84 (63.12 ± 10.80) and mean LVEDP was 17.20 ± 6.17 (16.57 ± 5.42). Using logistic regression with DSR, STR, age, height, and weight as features, sensitivity of 88.00%, specificity of 94.74%, AUC of 0.94, r = 0.74, p-value = 4.31e-06, were obtained for female patients; using DT/HR, STR, age, height, and weight, a sensitivity of 89.29%, specificity of 71.43%, AUC of 0.79, r = 0.40, and p-value = 0.0419 were obtained in the male patients. HEMOTAG detected elevated LVEDP with high sensitivity and high specificity for both female and male patients. This preliminary study has demonstrated the feasibility of estimating LVEDP using a portable, non-invasive device that empowers patients to transmit such data from home instantaneously to providers. Further studies are required to validate HEMOTAG as a point-of-care non-invasive assessment for heart failure and pulmonary hypertension patients. HEMOTAG® development and the clinical study is supported by NIMHD SBIR grant # R44MD009556.