A novel non-invasive method of estimating pulmonary vascular resistance in patients with pulmonary arterial hypertension.
ABSTRACT The assessment of pulmonary vascular resistance (PVR) plays an important role in the diagnosis and management of pulmonary arterial hypertension (PAH). The main objective of this study was to determine whether the noninvasive index of systolic pulmonary arterial pressure (SPAP) to heart rate (HR) times the right ventricular outflow tract time-velocity integral (TVI(RVOT)) (SPAP/[HR x TVI(RVOT)]) provides clinically useful estimations of PVR in PAH.
Doppler echocardiography and right-heart catheterization were performed in 51 consecutive patients with established PAH. The ratio of SPAP/(HR x TVI(RVOT)) was then correlated with invasive indexed PVR (PVRI) using regression and Bland-Altman analysis. Using receiver operating characteristic curve analysis, a cutoff value for the Doppler equation was generated to identify patients with PVRI > or = 15 Wood units (WU)/m2.
The mean pulmonary arterial pressure was 52 +/- 15 mm Hg, the mean cardiac index was 2.2 +/- 0.6 L/min/m2, and the mean PVRI was 20.5 +/- 9.6 WU/m2. The ratio of SPAP/(HR x TVI(RVOT)) correlated very well with invasive PVRI measurements (r = 0.860; 95% confidence interval, 0.759-0.920). A cutoff value of 0.076 provided well-balanced sensitivity (86%) and specificity (82%) to determine PVRI > 15 WU/m2. A cutoff value of 0.057 increased sensitivity to 97% and decreased specificity to 65%.
The novel index of SPAP/(HR x TVI(RVOT)) provides useful estimations of PVRI in patients with PAH.
- SourceAvailable from: Nelson B Schiller[show abstract] [hide abstract]
ABSTRACT: To evaluate a simple noninvasive means of estimating right atrial (RA) pressure, the respiratory motion of the inferior vena cava (IVC) was analyzed by 2-dimensional echocardiography in 83 patients. Expiratory and inspiratory IVC diameters and percent collapse (caval index) were measured in subcostal views within 2 cm of the right atrium. Parameters were correlated with RA pressure by flotation catheter within 24 hours of the echocardiogram (38 were simultaneous). Correlations between RA pressure (range 0 to 28 mm Hg), expiratory and inspiratory diameters and caval index were 0.48, 0.71 and 0.75, respectively. Of 48 patients with caval indexes less than 50%, 41 (89%) had RA pressure greater than or equal to 10 mm Hg (mean +/- standard deviation, 15 +/- 6), while 30 of 35 patients (86%) with caval indexes greater than or equal to 50% had RA pressure less than 10 mm Hg (mean 6 +/- 5). Sensitivity and specificity for discrimination of RA pressure greater than or equal to or less than 10 mm Hg were maximized at the 50% level of collapse. Thus, IVC respiratory collapse on echocardiography is easily imaged and can be used to estimate RA pressure. A caval index greater than or equal to 50% indicates RA pressure less than 10 mm Hg, and caval indexes less than 50% indicate RA pressure greater than or equal to 10 Hg.The American Journal of Cardiology 09/1990; 66(4):493-6. · 3.21 Impact Factor
- Journal of the American Society of Echocardiography 08/2003; 16(7):777-802. · 4.28 Impact Factor
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ABSTRACT: To determine the relationship between the degree of tricuspid regurgitation (TR) and accuracy of cardiac output measurement by thermodilution in mechanically ventilated patients. DESIGN AND SETTING. Prospective observational study in a 20-bed general intensive care unit in the university hospital. We examined 27 patients (not undergoing cardiac surgery): 8 with no or 1st degree TR, 9 with 2nd degree, and 10 with 3rd degree TR. All patients were measured twice using simultaneously transesophageal echocardiography and pulmonary artery catheter for cardiac output. Continuous Doppler measurements were taken in the left ventricular outflow tract at the level of the aortic valve. Cardiac output was calculated by multiplying the velocity-time integral by aortic valve area and heart rate. Simultaneous pulmonary artery catheter measurements were taken averaging the results of the three 10-cc boluses of iced saline. The difference between the methods was 0.5+/-1.1 l/min (mean +/-2 SD) in patients with no or 1st degree TR (r=0.96), 0.8+/-2.0 l/min in those with 2nd degree TR (r=0.92), and 1.9+/-2.3 l/min in those with 3rd degree TR (r=0.69). A high degree of TR is associated with underestimation of cardiac output measured by thermodilution.Intensive Care Medicine 09/2002; 28(8):1117-21. · 5.26 Impact Factor