A Multicenter Validation of a Noninvasive Brachial Cuff-ECG System for Estimation of Elevated Left Ventricular End Diastolic Pressure

Introduction: Measurement of left ventricular end diastolic pressure (LVEDP) is an established diagnostic method to evaluate all types of heart failure (HF). Invasive measurement of LVEDP requires an in-hospital procedure which limits accessibility. A noninvasive technique for detecting elevated LVEDP would significantly improve the diagnosis of HF, particularly in the outpatient setting. Herein we present the results of a multicenter study to validate a noninvasive system to detect elevated LVEDP. Methods: The Vivio System includes a modified blood pressure cuff and single lead ECG to capture brachial artery waveforms to assess preload, afterload and contractility. A model was created to identify patients with elevated LVEDP (> 18mmHg). 728 patients were enrolled from 7 medical centers in the USA. All patients were referred for coronary angiography and left heart catheterization for clinical indications. A group of 321 patients with no known significant health problems were enrolled as a control group. Invasive LVEDP measurements were conducted using Millar catheters. The control group was assumed to have a LVEDP = 10 mmHg. The training dataset (n = 262, mean age 45 ± 19 yrs; 54% male) contained 101 patients with LVEDP measurements (n = 44 with LVEDP > 18 mmHg) and 161 controls. The validation dataset (n = 155, mean age 46 ± 21 yrs; 62% male) contained 75 patients with LVEDP measurements (n = 40 with LVEDP > 18 mmHg) and 80 controls. Results: Leave-one-out cross-validation on the training dataset yielded a sensitivity of 0.84 (95% confidence interval (CI): 0.70 - 0.93) and a specificity of 0.84 (95% CI: 0.79 - 0.89). The validation dataset showed a sensitivity of 0.80 (95% CI: 0.64 - 0.91) and a specificity of 0.83 (95% CI: 0.75 - 0.90). Figure 1 shows the overall classification performance. Conclusion: The Vivio System can accurately detect elevated LVEDP and has the potential to significantly improve early detection of HF in the outpatient setting.