RESUMO
Objective To study the mechanism of right ventricular pulmonary artery coupling by fitting the pressure volume loop of pulmonary arterial hypertension patients and calculating the related parameters.Methods During January of 2015 to December of 2015,34 patients with pulmonary hypertension and 5 patients with patent oval foramen(PFO)were admitted in Wuhan Asian Heart Hospital,. Inclusion criteria for the pulmonary hypertension group were in accordance with the newest European guidelines for pulmonary hypertension . All of the patients were conducted invasive pressure catheter intervention and MRI. All the pressure data were digitized by GetData software and the CMR tools3D was used to derive right ventricular volume data, fitting the pressure volume loop and calculate the Pmax, Ees, Ea and other related parameters. 5 patients with PFO and 34 patients with pulmonary hypertension were divided into three groupswhich included:the control group (i.e. the patients with PFO), patients with pulmonary artery mean pressure less than 50 mmHg as group A and pulmonary artery mean pressure greater than or equal to 50 mmHg as group B. The pressure volume loop of the three groups were compared and the related parameters were calculated.Results The right ventricular Pmax were(53.05±12.87) mmHg, (134.73±26.38) mmHg, (207.88±65.67) mmHg, in the control group, group A and B respectively. There were significant differences when compared among the 3 groups. There was no statistical difference in Ees between the control group and group A(P>0.05). The Ees of group B was significantly higher than the control group[(1.53±0.97)vs.(0.60±0.28),P<0.05]. The Ea of group B was higher than the control[(1.34±0.74) vs.(0.39±0.15),P<0.05]. The overall ratio of Ees/Ea was lower in group B as compared to the control group [(1.12±0.47)vs.(1.62±0.51),P<0.05].Conclusions In the early stage of pulmonary hypertension, right ventricular contractility preserves and can overcome the slightly elevated afterload .The right ventricle and pulmonary artery coupled with good work. With the increasing mean pulmonary artery,the afterload of right ventricular increases and right ventricular contractility needs further increase to fight against the elevated afterload. The elevation of contractility cannot overcome the change of afterload, resulting in the off paired of mechanical efflciency, causing the right ventricle- pulmonary artery coupling decreases.
RESUMO
Fontan surgery is a widely used palliative procedure that significantly improves the survival period of patients with complex congenital heart disease (CHD). However, it does not decrease postoperative complication rate. Previous studies suggested that elevated mean pulmonary artery pressure (mPAP) and vascular resistance lead to decreased exercise tolerance and myocardial dysfunction. Therapy with endothelial receptor antagonists (Bosentan) has been demonstrated to improve the patients' prognosis. A double-blind, randomized controlled trial was performed to explore the efficacy of Bosentan in treating patients who underwent the Fontan procedure. Eligible participants were randomly divided into Bosentan group and control group. Liver function was tested at a local hospital and the results were reported to the phone inspector every month. If the results suggested abnormal liver function, treatment would be adjusted or terminated. All the participants finished the follow-up study, with no patients lost to follow-up. Unblinding after 2-year follow-up, no mortality was observed in either group. However, secondary end-points were found to be significantly different in the comparable groups. The cardiac function and 6-min walking distance in the Bosentan group were significantly superior to those in the control group (P=0.018 and P=0.027). Bosentan could improve New York Heart Association (NYHA) functional status and improve the results of the 6-min walking test (6MWT) in Fontan patients post-surgery, and no other benefits were observed. Furthermore, a primary meta-analysis study systematically reviewed all the similar clinical trails worldwide and concluded an overall NYHA class improvement in Fontan patients who received Bosentan treatments.