Echocardiography
All patients underwent transthoracic echocardiography using an iE33 or
EPIQ system (Philips Medical Systems, Andover, MA, USA) at our
echocardiography laboratory preoperatively, 1 week and 1year
postoperatively.
The TR grade was defined using a multiparametric approach, including an
assessment of the color Doppler-derived jet area, the continuous wave
Doppler-derived jet density and contour, and the hepatic vein flow
velocity pattern (12). TR was graded as none, trivial, mild, moderate,
or severe. For the statistical analysis, these TR grades were scored as
follows: none = 0, none to mild = 0.5, mild = 1, mild to moderate = 1.5,
moderate = 2, moderate to severe = 2.5, and severe = 3 (13).
Continuous wave Doppler was used to obtain the TR peak velocity (m/s)
and the transtricuspid systolic pressure gradient (TRPG, mmHg), which
was calculated as 4V2 (where V is velocity). The right
ventricular systolic pressure was then estimated as the sum of the
estimated TRPG and right atrial (RA) pressure. The RA pressure was
estimated as follows: an inferior vena cava diameter of ≤2.1 cm that
collapsed by ≥50% when the patient sniffed was considered to indicate a
normal RA pressure of 3 mmHg, whereas an inferior vena cava (IVC)
diameter of >2.1 cm that collapsed by <50% when
the patient sniffed was considered to indicate a high RA pressure of 15
mmHg. When the IVC diameter and collapse did not fit this paradigm, an
intermediate value of 8 mmHg was assigned (14). An estimated right
ventricular systolic pressure of >40 mmHg was considered
indicative of pulmonary hypertension (15). Tricuspid annular diameter
was measured at end-diastole and annular diameter of >40mm
or 21mm/m2 was considered significant annulus
dilatation (11). The RA dimension, left ventricular (LV) end-diastolic
dimension, LV end-systolic dimension, LV ejection fraction, and left
atrial (LA) dimension were measured according to the established
guidelines (14,16).