Abstract 15802: A Noninvasive, Hand-Held Device for Assessing Left Ventricular End-Diastolic Pressure Based on Finger Photoplethysmography and the Valsalva Maneuver
Introduction In many clinical settings, it is important to be able to estimate a patient’s left ventricular end-diastolic pressure (LVEDP). Unfortunately, current noninvasive methods have limited sensitivity, specificity, or convenience for assessing this important index of left heart filling pressure. The change in peripheral pulse pressure with the Valsalva maneuver has been shown to reflect invasively measured LVEDP. We have previously shown that the change in finger photoplethysmography (PPG) waveform amplitude with Valsalva maneuver (pulse amplitude ratio, PAR) also reflects LVEDP. In this study, we compared PAR with LVEDP using a dedicated, hand-held, battery-powered device with an automated algorithm for guiding patient use and calculating PAR.
Methods We tested 14 subjects (7 males), ages 42-70 years old, prior to their undergoing a clinically indicated left-heart catheterization. Each performed a Valsalva maneuver of 20 mmHg for 10 seconds into a transducer that measured expiratory pressure. Finger PPG was recorded continuously before and during the maneuver. PAR, the ratio of PPG amplitude prior to end of the Valsalva maneuver to PPG amplitude at rest, was automatically calculated.
Results The number of acceptable efforts averaged to calculate PAR for each subject was 5.6 ± 0.3. All subjects were able to complete at least one acceptable effort. The range of measured LVEDP over all subjects was 5 to 30 mmHg. The range of PAR was 0.35 to 1.03. There was a strong correlation between PAR and LVEDP (R=0.68, p=0.007). Further, a PAR > 0.72 had 78% sensitivity and 100% specificity for identifying LVEDP ≥ 15 mmHg.
Conclusion An index of left heart filling pressure was obtained using a dedicated, noninvasive, hand-held device based on finger photoplethysmography during the Valsalva maneuver. This index, pulse amplitude ratio, correlates well with invasively measured LVEDP, and has good sensitivity and specificity for identifying LVEDP ≥ 15 mmHg, a threshold value for LVEDP associated with increased mortality in heart failure. Larger studies are warranted to determine the reliability and clinical utility of this relation in various disease states.
- © 2012 by American Heart Association, Inc.