Assessment of diastolic function with Doppler tissue imaging after cardiac surgery: effect of the "postoperative septum" in on-pump and off-pump procedures.

Doppler tissue imaging (DTI) of mitral annular velocity is useful in assessing diastolic function. Most centers record at the septal or lateral segments of the annulus. Cardiopulmonary bypass produces changes in the motion of the interventricular septum. We evaluated the use of DTI after operation with and without cardiopulmonary bypass. 18 patients scheduled for cardiac surgery were prospectively examined. Nine underwent cardiopulmonary bypass. Nine had operation without bypass. DTI was performed 4 +/- 3 days before operation and again 31+/- 7 days afterwards. Early diastolic velocities of the lateral and septal segments of the mitral annulus were measured. Ejection fraction and transmitral diastolic early-to-late filling (E/A) ratios were also assessed. Early diastolic septal mitral annular velocity decreased (7.9 +/- 1.2 to 5.9 +/- 1.1 cm/s [P= .001]) after on-pump operation whereas lateral segment velocity remained unchanged (8.5 +/- 2.9 to 8.2 +/- 3.7 cm/s [P = .30]). E/A ratio did not change after operation (1.28 +/- 0.25 to 1.21 +/- 0.47 [P = .45]). In contrast, septal segment velocity in the off-pump group trended higher after operation (5.3 +/- 1.9 to 6.0 +/- 1.5 cm/s [P = .20]). Lateral segment velocity and E/A ratio also increased somewhat, but changes were not significant (6.2 +/- 1.7 to 6.7 +/- 2.9 cm/s [P = .15] and 1.1 +/- 0.5 to 1.2 +/- 0.4 [P = .13], respectively). Ejection fraction increased in both groups. Early diastolic velocity of the septal mitral annulus decreases after operation with cardiopulmonary bypass, but does not change after off-pump operation. In contrast, early diastolic velocity of the lateral segment is not affected by either on-pump or off-pump operation. Measuring lateral segment velocity is recommended for diastolic DTI after cardiopulmonary bypass, as septal DTI may incorrectly suggest diastolic dysfunction.