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

Noninvasive Evaluation of Pulmonary Capillary Wedge Pressure by BP Response to the Valsalva Maneuver: DiscussionIn 11 patients (mean age, 51 ± 13 years), repeat measurements of the PCWP were performed 3.2 ± 4.5 months after the first examination. In these 11 patients, changes in the PAR predicted changes in the invasively measured PCWP with very good accuracy (R2 = 0.93; root mean square error = 2.6 mm Hg; p < 0.001) [Fig 5]. It is important to note that the slope of the regression line (32.7 ± 2.9) was nearly identical to that of the first measurement in the whole study population (32.0 ± 2.9) and that the constant of this regression line was close to 0 (0.6 ± 0.8).
11 patients showed a square-wave response to the VM. Eight of these patients had a left ventricular ejection fraction of < 40%. Taking into account these 11 patients did not influence the overall results. In the present study, the ratio of the pulse pressure amplitude changes during the VM correlated with the invasively measured PCWP. In particular, our data show that an elevated PCWP (ie, > 15 mm Hg) can be detected with clinically meaningful accuracy. Canadian family pharmacy online Here This is in concordance with previous observations by McIntyre et al. In addition, changes in PCWP may be assessed noninvasively not only in the short term but also, as shown in this study, in the long term. Thus, changes in pulse amplitude during the VM may be helpful in the routine screening of patients with suspected elevations of PCWP and in the assessment of success of therapy in patients with CHF. Furthermore, this noninvasive method is independent of heart failure therapy (eg, P-blockers, amiodarone, ACE inhibitors, digoxin, and diuretics).
During the straining phase of the VM, the arterial pressure rises with maintained pulse amplitude as a result of the transmission of the increased intratho-racic pressure to the periphery (phase 1). Due to a decrease in venous return, decreased stroke volume then leads to an acute drop in BP and a narrowing of the pulse amplitude with a compensatory rise in heart rate and peripheral vascular resistance (phase 2).
Figure 5. Scatterplot of changes in the pulse PAR and the invasively measured PCWP of repeat measurements in 11 patients.