Relationship of pulmonary artery diastolic and pulmonary artery wedge pressures in mitral stenosis

Resting and exercise hemodynamic studies were performed in 33 patients with mitral stenosis (14 men and 19 women; average age, 25 years) in normal sinus rhythm with normal pulmonary vascular resistances. A normal pulmonary vascular resistance was assumed when the resting pressure gradient between the pulmonary artery diastolic and mean pulmonary artery wedge pressures was 5 mm. Hg or less. A satisfactory correlation existed between the pulmonary artery wedge and pulmonary artery diastolic pressures at rest (r = 0.9017) and during exercise (r = 0.8670). A method of predicting pulmonary artery wedge pressure from pulmonary artery diastolic pressure during exercise was formulated. The correlation between the predicted and measured exercise pulmonary artery wedge pressures was very close (r = 0.9561). It is suggested that during exercise the pulmonary artery diastolic pressure can be modified as above and substituted for mean pulmonary artery wedge pressure if the resting gradient between pulmonary artery wedge and pulmonary artery diastolic pressure is known.     

Estimation of pulmonary artery pressure from pulmonary vein wedge pressure

Correlations between pulmonary artery and pulmonary vein wedge pressures were investigated in 13 patients with atrial septal defect and 1 patient with Tetralogy of Fallot. Pulmonary vein wedge pressure wave form resembled that of pulmonary artery pressure, and the former lagged behind the latter by 70 to 110 msec (mean 88 ± 14) as observed by the fluid-filled catheter system. Diastolic pulmonary artery and diastolic pulmonary vein wedge pressures were nearly identical. Although systolic and mean pulmonary artery pressures correlated well with respective pulmonary vein wedge pressures, there were discrepancies when systolic and mean pulmonary artery pressure exceeded 35 and 20 mm Hg, respectively. However, systolic and mean pulmonary artery pressures could be estimated by adding the difference between the diastolic pulmonary vein wedge pressure and the mean left atrial pressure to corresponding systolic or mean pulmonary artery pressure. In conclusion, pulmonary artery pressures can be estimated by measuring pulmonary vein wedge pressures and the mean left atrial pressure.     

Correlation of pulmonary capillary wedge pressure with left atrial pressure in patients with mitral stenosis undergoing balloon valvotomy

AimsWe sought to evaluate the correlation between PCWP and LAP and to compare transmitral gradients obtained with LAP and PCWP in MS, before and after balloon mitral valvotomy (BMV).MethodsConsecutive patients with MS for BMV were included in this prospective cohort study. Simultaneous PCWP and LAP were recorded followed by simultaneous left atrium–left ventricular (LA–LV) and pulmonary capillary wedge pressure–left ventricular (PCWP–LV) gradients before and after BMV.ResultsThere were 30 patients with a mean age of 41 yrs (males 10 (33.3%), females 20 (66.7%)). There was no significant difference between mean LAP and mean PCWP before BMV (21.3 mmHg and 22.3 mmHg, respectively) or after BMV (15.3 mmHg and 17.3 mmHg, respectively). There was excellent correlation between mean PCWP and mean LAP before BMV (r = 0.95) (p < 0.001) and after BMV (r = 0.85) (p < 0.001). The phasic components of the pressures (a and v waves) of LAP and PCWP also showed good correlation before and after BMV. Further, transmitral gradients assessed by LA–LV and PCWP–LV pressures showed excellent correlation before BMV (r = 0.95) (p < 0.001) and after BMV (r = 0.95) (p < 0.001).ConclusionIn patients with MS undergoing balloon valvotomy, PCWP shows good correlation with LAP. Transmitral gradients obtained with PCWP and LAP also correlate well after correction of phase lag in PCWP tracing. Hence, PCWP can be used for reliable measurement of transmitral gradient.     

Congenital pulmonary vein stenosis: structural changes in a patient with normal pulmonary artery wedge pressure

A male infant is described who died at 13 months of age with stenosis of all extrapulmonary veins except the left upper vein. The pulmonary artery wedge pressure was normal, the first time this is reported in this condition. At autopsy, there were structural changes of the pulmonary arteries and veins in all lobes with or without pulmonary vein stenosis. Arterial changes-muscle extension, medial hypertrophy and decreased arterial size--analyzed quantitatively were found to be similar in all lobes. Venous medial hypertrophy was more marked in obstructed lobes. These anatomic changes are presumably due to fixed venous obstruction in the pulmonary lobes drained by stenotic veins and to high flow in the left upper lobe.     

Accuracy of left atrial and pulmonary artery wedge pressure in pure mitral regurgitation in predicting left ventricular end-diastolic pressure

In most clinical conditions pulmonary artery (PA) wedge pressure accurately reflects left ventricular (LV) end-diastolic pressure. In the presence of mitral regurgitation (MR), large V waves can distort PA wedge pressure and result in incorrect estimation of LV end-diastolic pressure. In 52 patients with MR simultaneous measurement of PA wedge pressure or left atrial pressure and LV end-diastolic pressure was recorded. Twenty-one (40%) patients had large V waves (V wave greater than A wave by greater than 10 mm Hg, group 1), and 31 (60%) patients had small V waves (group 2). Group 1 had significantly higher V waves than group 2 (46 +/- 3 vs 21 +/- 2 mm Hg, p less than 0.001). The LV end-diastolic pressure was similar in both groups (21 +/- 2 vs 19 +/- 2 mm Hg, difference not significant). The mean PA wedge or left atrial pressure in group 1 (26 +/- 2 mm Hg) overestimated LV end-diastolic pressure (21 +/- 2 mm Hg) by 30% (p less than 0.01), but the trough of the X descent (20 +/- 2 mm Hg) was similar to the LV end-diastolic pressure. In group 2 patients with small V waves the mean PA wedge pressure was not significantly different from the LV end-diastolic pressure (16 +/- 2 vs 19 +/- 2 mm Hg, p = 0.06), but the trough of the X descent (13 +/- 2 mm Hg) underestimated LV end-diastolic pressure.(ABSTRACT TRUNCATED AT 250 WORDS)     

Use of pulmonary capillary wedge pressure to assess severity of mitral stenosis: is true left atrial pressure needed in this condition?

There is disagreement concerning the use of the pulmonary capillary wedge pressure (in place of left atrial pressure) in assessing the presence and severity of mitral valve disease. This study was done to assess the accuracy and reliability of an oximetrically confirmed pulmonary capillary wedge pressure in measuring the transvalvular pressure gradient and valve area in patients with mitral stenosis. In 10 patients with mitral stenosis (1 man and 9 women; mean age +/- SD 47 +/- 7 years), pulmonary capillary wedge pressure was measured through an 8F Goodale-Lubin catheter with its wedge position confirmed by oximetry (oxygen saturation greater than or equal to 95%). In addition, a transseptal left atrial pressure was measured through a Brockenbrough catheter and left ventricular pressure was measured through a pigtail catheter. The mean and phasic left atrial and pulmonary capillary wedge pressures were similar (mean left atrial pressure 18 +/- 6 mm Hg; mean pulmonary capillary wedge pressure 18 +/- 8 mm Hg; p = NS). When the pulmonary capillary wedge pressure was used without adjustment for time delay, the transvalvular pressure gradient (9.8 +/- 3.3 mm Hg) and valve area (1.5 +/- 0.5 cm2) were significantly different (p less than 0.05) from the values obtained with use of left atrial pressure (7.2 +/- 2.9 mm Hg and 1.7 +/- 0.6 cm2, respectively). In contrast, when the pulmonary capillary wedge pressure was adjusted for the time delay through the pulmonary vasculature, the difference in gradients averaged only 1.7 mm Hg and the mitral valve areas were similar.(ABSTRACT TRUNCATED AT 250 WORDS)     

Tight mitral stenosis with normal unilateral pulmonary capillary pressure

There are few reports of severe mitral stenosis with normal pulmonary artery wedge pressure. In order to illustrate this problem we present two adult patients with these abnormalities. Both patients had intact interatrial septum with partial anomalous pulmonary venous drainage, one to the inferior vena cava (The Scimitar Syndrome) and the other to the superior vena cava. In the first case the right pulmonary artery wedge pressure was 11 mm Hg. In the second case this pressure was only 8 mm Hg. Pulmonary arteriograms are of paramount importance in the diagnosis and surgical management. In both cases the surgical procedure with mitral commissurotomy and transplant of the anomalous pulmonary veins to the left atrium was successful.     

Overestimation of mitral valve gradients obtained by phasic pulmonary capillary wedge pressure

We investigated the relationship between left atrial (LA) and pulmonary capillary wedge pressure (PCW) in order to define the clinical settings in which PCW may be used to approximate LA pressure and to determine the cause and significance of difference between LA and PCW pressures. Nineteen patients who at cardiac catheterization had LA, PCW, and left ventricular (LV) pressures recorded, had mitral valve gradients and areas determined. Mean PCW and LA pressures correlated well (r = 0.94). Phasic PCW consistently overestimated the MV gradient and underestimated the MV area compared to LA pressure, (8 ± 4 versus 4 ± 3 mm Hg, p < 0.001, 1.3 ± 0.3 versus 1.6 ± 0.3 cm², p < 0.005, respectively). Three patients had abnormal MV prosthesis function assessed by PCW pressure but not by LA pressure. Diastolic MV gradients between PCW and LV were caused or increased by a slowed y descent in the PCW tracing. Using the PCW pressure may falsely elevate MV gradients and falsely reduce MV areas and lead to incorrect clinical action.     

Pulmonary capillary wedge pressure in mitral stenosis accurately reflects mean left atrial pressure but overestimates transmitral gradient

Current opinion varies as to whether pulmonary capillary wedge pressure assessment of transmitral gradient in mitral stenosis is accurate; we therefore compared transmitral gradient in 36 patients awaiting balloon valvuloplasty using both pulmonary capillary wedge pressure and direct left atrial pressure. Mean pulmonary capillary wedge pressure correlated well with mean left atrial pressure (limits of agreement -1.5 to +3.7 mm Hg), but mean diastolic mitral gradient calculated using pulmonary capillary wedge pressure differed significantly from that calculated using left atrial pressure (limits of agreement -1.2 to +9.8 mm Hg): wedge pressure-assessed transmitral gradient is therefore misleading, routinely overestimating stenosis severity.     

Prospective study comparing different echocardiographic measurements of pulmonary capillary wedge pressure in patients with organic heart disease other than mitral stenosis

In 25 patients with cardiac disease, but free of left ventricular inflow obstruction, the electrocardiogram and M-mode echocardiogram of the aortic root, left atrium and both the mitral and the aortic valves were obtained simultaneously with the pulmonary artery wedge pressure (PAWP) during right heart catheterization. The echocardiographic measurements of the left atrial size, PR-AC interval, left atrial emptying index and the ratio between the electrocardiographic Q wave to mitral valve closure (Q-MVC) and between aortic valve closure to the mitral E point (AVC-E) were correlated to the pulmonary artery wedge pressure by means of linear regression analysis. A formula in which PAWP = 36.6 (Q-MVC/AVC-E)-- 2 was prospectively used to study the measured pressure in the current group of patients. The pulmonary artery wedge pressure derived from these latter measurements correlated well with the invasive measurement of this pressure (r = 0.91). The pulmonary artery wedge pressure calculated by echocardiography differed from the pulmonary artery wedge pressure measured by catheterization by 3 mm Hg or less in 19 of the 25 patients, by 4 mm Hg or less in 22 patients and by 6 mm Hg or less in 24 patients. Although the correlation between the (Q-MVC/AVC-E) ratio and measured pulmonary artery wedge pressure was highly significant (r = 0.91, probability [p] less than 0.001, n = 25), the left atrial emptying index, PR-AC and left atrial size revealed poor correlation coefficients (r = 0.45, r = 0.45 and r = 0.56 [p less than 0.05]), respectively.(ABSTRACT TRUNCATED AT 250 WORDS)     

Relation of left atrial size to pulmonary capillary wedge pressure in severe mitral regurgitation

4,071 consecutive cardiac catheterizations were reviewed retrospectively to obtain 56 cases of pure mitral regurgitation among whom chest X-ray, electrocardiography and echocardiography had been performed within 10 days of catheterization. Mitral regurgitation was mild to moderate (1-2+) in 7 of the 56 cases while 49 had more severe regurgitation (3-4+). Left atrial size as measured by echocardiography was found to be enlarged in all but 2 cases. A positive correlation between left atrial size and severity of mitral regurgitation, irrespective of the height of the pulmonary capillary wedge pressure V wave was demonstrated. There was no demonstrable, predictive relationship between left atrial size and pulmonary capillary wedge pressure or electrocardiographic or chest X-ray findings. We conclude that knowledge of left atrial size is predictive of the severity of mitral regurgitation; however, it is not possible to predict the pulmonary capillary wedge pressure or height of the V waves based on a knowledge of left atrial dilatation in patients with pure mitral regurgitation.