| Objective: Pulmonary embolism (PE) is a clinical syndrome of pulmonary circulation dysfunction caused by pulmonary vascular obstruction. The obstruction is due to the embolus and vasoconstriction. PE has a high misdiagnose rate and high mortality in clinical practice. Many reports have shown the usefulness of helical CT angiography in the diagnosis of acute PE . However, most previous studies were focused on helical CT performance to detect PE and widely described features of arterial emboli. One of the latest studies showed the CT obstruction index could quantify arterial obstruction in PE, which had a good correlation with pulmonary angiography. Many studies have proved that there is important association between the right ventricular function and the degree of pulmonary obstruction. Echocardiography is a important noninvasive method in diagnosis of PE. Especially, it can detect the right ventricular function, which is proved associated with prospect of PE. Although echocardiography plays an important role in noninvasive assessment of cardiac function, evaluation of the right ventricle(RV) is difficult and dissatisfactory toconventional echocardio- graphy because of the anatomic and functional complexity of this chamber. Tissue Doppler imaging (TDI) , a novel technique recently incorporated into echocardiographic studies, enables direct quantitative measurements of myocardial velocities of contraction and relaxation. Nevertheless, it has not yet been used in evaluation of right ventricular function of patients with acute PE. The purpose of this study was to investigate the changes of TDI parameters of RV function before treatment and one week after treatment, and the usefulness of TDI in the diagnosis and the evaluation of therapeutic effect on the acute pulmonary embolism.Methods: Thirteen adult pulmonary embolism patients were included in this study. Exclusionary criteria included the followings: ⑴pre-existing cardiac or pulmonary disease; ⑵need for mechanical ventilation support; ⑶ systolic blood pressure <90mmHg or administration of vaso-pressors required to maintain a systolic blood pressure >90mmHg; ⑷ symptoms lasted for more than one month; ⑸ a history of previous diagnosed pulmonary embolism within the previous year. TDI and helical CT were performed in patients before treatment and one week after treatment. Patients underwent TDI within 12 hours after helical CT examination. The machine for Doppler echocardiographic study was a commercially available ultrasound system equipped with TDI analysis software. The following echocardiographicparameters were assessed: RV end diastolic area / LV end diastolic area, RV ejection fraction by area-length method. Longitudinal contraction and expansion velocities of the interventricular septum(IVS) and the lateral wall of the RV through an apical 4-chamber approach were determined by TDI in the basal, middle and apical segments of the referred walls. Peak systolic velocity, early and late diastolic velocities and the ratio between them were obtained and averaged from three consecutive beats. The helical CT criterion used to diagnose pulmonary emboli consisted of central filling defect completely or partially outlined by contrast agent. To define the CT obstruction index, the arterial tree of each lung was regarded as having 10 segmental arteries (three to the upper lobe, two to the middle lobe and to the lingual, and five to the lower lobe). The presence of embolus in a segmental artery was scored 1 point, and emboli in the most proximal arterial level were scored a value equal to the number of segmental arteries arising distally. To provide additional information about the residual perfusion distal to the embolus, a weighting factor was assigned to each value, depending on the degree of vascular obstruction. This factor was equal to zero, when no thrombus was observed; 1, when partially occlusive thrombus was observed; or 2, with total occlusion. Thus, the maximal CT obstruction index was 40 per patient. The percentage of vascular obstru... |
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