Usefulness of onset of the pulmonary wedge V wave in predicting mitral regurgitation

Invasive assessment of mitral regurgitation: Comparison of hemodynamic parameters

OBJECTIVES

We sought to analyze several new hemodynamic characteristics which address the interplay of left atrial (LA) and left ventricular (LV) pressures, as well as to re-analyze several other V wave characteristics employed in the determination of mitral regurgitation (MR) severity in order to determine which, if any, had adequate correlation with grade of MR for clinical utility.

BACKGROUND

Invasive assessment of mitral regurgitation includes analysis of intracardiac pressures and LV angiography. The V wave, when obtained from the pulmonary capillary wedge position (PCWP), and its various characteristics are believed to be of limited value for prediction of MR severity.

METHOD

We analyzed the transeptal pressure tracings of patients with various degrees of MR. Several relationships from the simultaneous pressure-time curves of the LA and LV were defined. Biplane left ventricular angiography was used to grade MR. Correlation between each parameter and MR grade was determined by calculating a Pearson correlation coefficient.

RESULTS

The ratio of the area under the V wave to the LV systolic area (V(a)/LV(a)) best correlates with the degree of MR with a Pearson correlation coefficient of 0.60. The V(a)/LV(a) was significantly lower in patients with 0-1+ MR compared to > or =2+ MR (0.14 vs. 0.23 p = 0.002).

CONCLUSIONS

Invasive hemodynamic assessment of MR severity could be enhanced by calculating our new ratio, V(a)/LV(a), due to its ability to account for LV work that is lost to the LA with a proportional decrease in forward or useful LV work with progressively increasing severity of MR.

Relationship between pulmonary capillary wedge V wave and transmitral and pulmonary venous flow velocity patterns in various heart diseases

BACKGROUND

A large V wave in a pulmonary capillary wedge pressure (PCWP) tracing is characteristic of mitral regurgitation. However, the V wave is often increased in patients without or with no significant mitral regurgitation.

METHODS AND RESULTS

The V wave was in the PCWP tracing investigated in 65 patients using transmitral flow (TMF) and pulmonary venous flow (PVF) velocity patterns obtained by transesophageal pulsed Doppler echocardiography. A large V wave was defined if the peak V wave minus the mean PCWP (V-mPCWP) was greater than 7 mmHg. Three study groups were formed: 15 patients with large V waves and significant mitral regurgitation, 15 patients with large V waves with no significant mitral regurgitation, and 35 patients with small V waves. The mPCWP and left ventricular end-diastolic pressure were greatest in the group with large V waves and no significant mitral regurgitation. Peak early diastolic TMF and PVF velocities were significantly greater in the two groups with large V waves. The peak second systolic PVF velocity was lowest in the group with large V waves and significant mitral regurgitation, followed by the group with large V waves and no significant mitral regurgitation. The V-mPCWP was positively correlated with the peak early diastolic TMF and PVF velocities and negatively correlated with the peak second systolic PVF velocities. Additionally, mitral regurgitation severity in patients with large V waves and significant mitral regurgitation was positively correlated with the peak early diastolic TMF and PVF velocities and negatively correlated with the peak second systolic PVF velocity.

CONCLUSIONS

These results suggest that large V waves in PCWP tracings appear not only in severe mitral regurgitation, but also in any condition with markedly elevated left ventricular end-diastolic pressure. Combined analysis of the TMF and PVF velocity patterns is helpful in determining the etiology of these hemodynamic abnormalities.

Predictive value of prominent pulmonary arterial wedge V waves in assessing the presence and severity of mitral regurgitation

Indwelling pulmonary arterial catheters are often used to monitor and to guide therapy in critically ill patients. The magnitude of the V wave recorded from the pulmonary arterial wedge (PAW) position is sometimes used to assess the presence and severity of mitral regurgitation (MR). The present study was performed to assess the relation (or lack thereof) between a "prominent" PAW V wave and qualitative and quantitative estimates of MR. In 903 subjects (445 men and 458 women, aged 49 +/- 13 [mean +/- SD] years) referred for cardiac catheterization, an oximetrically confirmed PAW pressure was recorded with a large-lumen stiff catheter, and a left ventriculogram was recorded. In 646 of these subjects (328 men and 318 women, aged 50 +/- 13 years), forward cardiac output was measured by the Fick principle, and a regurgitant fraction was calculated. Prominent PAW V waves--as defined in several ways--were insensitive and had poor positive predictive value in identifying moderate or severe MR. At the same time, the absence of prominent PAW V waves was relatively specific for the absence of moderate or severe MR, and the negative predictive value of small V waves was very good. Thus, the prominence of a PAW V wave cannot be used to assess the presence or severity of MR.

Interpretation of cardiac pathophysiology from pressure waveform analysis: the left-sided V wave

The left-sided V wave is dependent on both left atrial and ventricular pressure/volume filling relationship. The cardiac rhythm and timing of atrial systole also influences the V wave. The morphology of the V wave can reflect the severity of mitral regurgitation with stenosis, but valve areas in this setting may be better assessed by a pressure half-time method. Finally, as queried in our first patient example, V wave alternans is a reflection of left ventricular pressure alternans in a failing heart. Other signs of poor left ventricular function in Figure 1 also included an elevated minimal diastolic pressure and markedly elevated left ventricular end diastolic pressure. Hemodynamic findings of poor left ventricular function will be addressed in detail in a later "Rounds."