Abstract
The pulse amplitude ratio, the ratio of pulse pressure at the end of a Valsalva maneuver to before the onset of Valsalva, correlates with filling pressure. This study aimed to noninvasively estimate cardiac filling pressure in patients with heart failure. We developed a noninvasive handheld device to measure pulse amplitude ratio using finger photoplethysmography. In 69 patients who underwent right heart catheterization, photoplethysmography waveforms were recorded during a standardized Valsalva maneuver, and in 60 of these patients, pulse amplitude ratio was able to be calculated. Pulse amplitude ratio correlated with pulmonary capillary wedge pressure (PCWP) (r = 0.58, p <0.0001), particularly among those subjects with reduced ejection fraction (r = 0.60, p = 0.002, n = 25). A multivariable linear regression model for PCWP including pulse amplitude ratio, age, body mass index, systolic blood pressure, diastolic blood pressure, and heart rate yielded an R2 of 0.54. Difference in mean pulse amplitude ratio for subjects with a PCWP ≤15 mm Hg versus >15 mm Hg was statistically significant (p <0.0001, area under receiver operating characteristics curve 0.79 [0.66, 0.92]). Pulse amplitude ratio ≥0.55 predicted PCWP >15 mm Hg with 73% sensitivity and 77% specificity. Pulse amplitude ratio also increased by an average of 0.03 with a leg raise maneuver (p = 0.05, n = 36). In conclusion, we demonstrate that noninvasively measured response to the Valsalva maneuver in patients with HF can estimate PCWP and also detect changes within a single patient.
Published Version
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