Objective: Right ventricular (RV) failure is the main cause of mortality in patients with pulmonary hypertension (PH). Therefore, there is an increasing interest for the assessment of RV function. This study aimed to evaluate the regional RV function in patients with PH by using ultrasonic strain rate imaging.
Methods: In all, 27 patients with PH and 27 control subjects were studied by ultrasonic strain rate imaging. The regional longitudinal deformation was measured in the RV free wall divided into two segments. A subgroup of 16 patients had concomitant invasive hemodynamic measurements.
Results: In patients with PH, deformation parameters were significantly lower compared with that of control subjects (basal strain rate -2.28 +/- 0.9 vs -2.94 +/- 0.9 s(-1); strain -28 +/- 13% vs -42 +/- 11%; apical strain rate -1.05 +/- 1.38 vs -2.60 +/- 0.9 s(-1); strain -13 +/- 16% vs -41 +/- 11%, respectively). The deformation parameters in the apical segment were reduced more than in the basal segment (the segment-wise comparison with P < .002 for strain rate and P < .0001 for strain) in the patient group. The reduction of the apical deformation was related to the severity of RV afterload. Strong correlations were found between the apical strain and invasively measured mean pulmonary arterial pressure (R = 0.82, P < .0001) and pulmonary vascular resistance (R = 0.73, P < .001) and echocardiographically estimated hemodynamic parameters, RV size and global function, and exercise capacity (evaluated by a 6-minute walk test expressed as a percentage of the expected value).
Conclusion: Strain rate imaging provides a new tool to quantify regional RV dysfunction in patients with PH and reveals a characteristic regional pattern of abnormal RV free wall function.