Non-Invasive Venous Waveform Analysis (NIVA) for Estimation of Pulmonary Capillary Wedge Pressure
Heart failure is the leading cause of hospitalization in the elderly and there remains an unmet need for accurate non-invasive assessment of congestion in patients with heart failure. Non-Invasive Venous waveform Analysis (NIVA) is a novel, non-invasive technology that acquires and analyzes the peripheral venous waveform from the wrist. The main objective of this thesis was to develop an algorithm for calculation of a NIVA value and assess the correlation between NIVA value and pulmonary capillary wedge pressure (PCWP). The secondary objectives were to assess the ability of NIVA to detect PCWP>18mmHg, and to investigate the correlation between non-invasive thoracic impedance technology (ZOE®) and PCWP. NIVA signals were acquired from 78 subjects undergoing right heart catheterization (RHC). The NIVA algorithm to estimate PCWP was developed using Lasso linear regression. ZOE® measurements were also obtained in 20 subjects. Pearson correlation was used to determine correlations between NIVA value or ZOE® value and PCWP. A Receiver Operating Characteristic (ROC) curve was used to determine whether a NIVA value could predict PCWP>18 mmHg (a value consistent with congestion or volume overload). 50 subjects had adequate signal for analysis. The NIVA value demonstrated a positive correlation with PCWP (r=0.76, p<0.05). ZOE® did not correlate with PCWP (r=-0.03, p=0.89). NIVA was able to predict PCWP>18mmHg with a sensitivity of 73% and specificity of 80% (AUC=0.83, p<0.05). NIVA is a non-invasive monitoring technology that provides an estimate of PCWP and has potential for guidance of decongestive therapy in heart failure patients.