Studies have shown that the ratio of mitral inflow and mitral annular tissue Doppler velocity (TDV) may non-invasively predict mean pulmonary capillary wedge pressure (PCWP). It known that there is a significant difference between septal vs. lateral wall TDV. In the absence of standard guidelines it is not clear which of these two (septal vs. lateral wall) velocities should be used for this purpose.
Fifteen consecutive cardiac surgery post-op patients were studied. Patients undergoing mitral valve surgery were excluded. The ratios of mitral inflow velocity to both septal as well as lateral mitral annular velocities were compared to instantaneous measurements of PCWP. The peak early diastolic velocity of transmitral flow (E) was measured by pulsed-wave Doppler and the peak early diastolic velocities of the lateral (LEa) and septal (SEa) mitral annulus using pulsed-wave tissue Doppler imaging. The ratios of E to LEa (E/LEa) and SEa (E/SEa) were calculated separately. Immediately after echocardiography, PCWP was measured using a balloon-tipped pulmonary artery catheter.
PCWP ranged from 7–22 mm Hg. Both E/LEa and E/SEa showed an excellent correlation with PCWP (r) = 0.97 (95% CI 0.85 to 0.99 and p < 0.0001) and (r) = 0.98 (95% CI 0.88 to 0.99, p < 0.0001) respectively. However, E/LEa measurements were closest to direct PCWP measure with average difference of 0.83 mmHg or 10.9% (Range −1.36 to +3.1 mm Hg) as compared to E/SEa which showed a marked variation in comparison; average 6.3 mm or 62.5% (range +2.6 to +8.1 mm Hg). When a cut-off ratio of 15 for elevated ( > 15 mmHg) versus not elevated PCWP is used, E/SEa would have mis-stratified 6 patients compared to none in the E/LEa group.
E/LEa gives a better non-invasive assessment of PCWP.
The absence of standard guidelines for Ea measurements and the major differences in septal vs. lateral wall Ea velocities, might be the reason behind lack of consensus in previous studies.
Janardhan Srinivasan, No Financial Disclosure Information; No Product/Research Disclosure Information