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Noninvasive Evaluation of Pulmonary Capillary Wedge Pressure by BP Response to the Valsalva Maneuver: Statistical Analysis

Noninvasive Evaluation of Pulmonary Capillary Wedge Pressure by BP Response to the Valsalva Maneuver: Statistical AnalysisTwo measurements were performed within 3 to 5 min, and mean values for both PCWP and PAR were used for analysis. Immediately before each of the two VMs, the mean PCWP was invasively measured by a 7F balloon-tipped pulmonary catheter and was recorded on paper with a speed of 100 mm/s and a pressure range of 40 mm Hg.
In 11 patients, measurements were repeated after changes in medical therapy by the same procedure as described > 3.2 ± 4.5 months later. In these patients, changes in PCWP were compared with changes in the BP response to the VM.
Values were expressed as frequency and mean ± SD, as indicated. A standard least-squares linear regression analysis was used to analyze the capacity of the PAR to predict the PCWP. The same method was used for the differences in 11 patients with serial measurements. A Bland-Altman plot was used to depict individual variance from an estimated value of PCWP. A receiver operating curve (ROC) was used to assess diagnostic accuracy to detect an elevated PCWP (ie, > 15 mm Hg). All statistical analysis was performed using a commercially available statistical program (SPSS, version 9.0; SPSS; Chicago, IL).
Results
The characteristics of our study population are shown in Table 1. Twenty-seven patients (64%) were receiving angiotensin-converting enzyme (ACE)-inhibitors, 8 patients (19%) were receiving (3-blockers, 11 patients (26%) were receiving amiodarone, and 24 patients (57%) were receiving digoxin.
Table 1—Patient Characteristics

Characteristics Values
Age, yr 58 ± 13
Gender
Male 8
Female 34
EF, % 38 ± 22
Heart rate, beats/min 73.4 ± 16.4
Cardiac index, L/min/kg 2.4 ± 0.4
CVP, mm Hg 5.2 ± 4.4
MPAP, mm Hg 25.4 ± 10.9
PCWP, mm Hg 15.6 ± 8.2
ACE inhibitor 27 (64)
Betablocker 8 (19)
Amiodarone 12 (29)
Diuretics 27 (64)
Digoxine 24 (57)
Nitrate 21 (51)