A COMPARISON BETWEEN SYSTOLIC AORTIC ROOT PRESSURE AND FINGER BLOOD-PRESSURE

Background: Digital photoplethysmography is used to assess hemodynamic variability and baroreflex sensitivity. Numerous studies have critica lly evaluated the accuracy of the photoplethysmographic device against peripheral pressure. The aim of our study was to compare finger blood and aortic root pressure. Methods: We prospectively compared simultan eous recordings of systolic pressure at the aortic root and finger lev el over three consecutive respiratory cycles in 15 patients (56+/-11 y ears) undergoing routine cardiac catheterization, Data were obtained a t baseline, during deep breathing maneuver (0.1 Hz), and after left ve ntricular cineangiography. Results: At baseline, systolic finger press ure overestimated systolic aortic pressure (145.2+/-22.5 vs 115.0+/-20 .1 mm Hg; p<0.001). The pressure difference (30.2+/-17.0 mm Hg) was no t influenced. by systolic aortic pressure. There was no relationship b etween pressure difference and the main determinants of the pulse wave amplification phenomenon. There was a bent-to-beat relationship betwe en finger and aortic pressure in 14 of 15 subjects (slope ranging from 0.37 to 1.70; ordinate: from -58 to +98 mm Hg), During the deep breat hing maneuver and after left ventricular cineangiography, finger press ure still overestimated aortic pressure by 32.3+/-15.0 mm Hg and 38.3/-13.9 mm Hg, respectively teach p<0.001), There was a beat-to-deat re lationship between systolic aortic root pressure (IAoBP) and systolic finger (FBP) in 13 of 15 patients, with major scattering of both slope s and ordinates. Throughout the study, there was no predictable relati onship between the level of IAoBP and pressure bias. Conclusions: As e xpected, FBP was almost always higher than IAoBP. Importantly, the dif ferences in systolic pressure did not correlate with known determinant s of the pulse wave amplification phenomenon. The device must be used cautiously if one wants to noninvasively track spontaneous or induced changes in IAoBP.