四维血流心血管MR分析肺动脉高压患者右心室血流特征

4D-FLOW cardiovascular MR in assessment of right ventricular flow in patients with pulmonary hypertension

目的采用四维血流(4D-FLOW)心血管MR(CMR)技术观察肺动脉高压(PH)患者右心室血流特征,探讨右心室血流成分与右心室功能及血流动力学的关系。方法前瞻性纳入2019年6月至2020年10月于中日友好医院确诊PH患者30例。所有患者均于1周内行右心漂浮导管测定血流动力学并行CMR测定右心室血流及右心功能。采用平衡稳态自由进动序列采集心脏电影序列,测定右心室舒张末期容积、收缩末期容积、射血分数、每搏输出量等功能参数。采用三维回顾性心电图触发导航仪门控4D-FLOW序列进行全心血流扫描,测定右心室直接血流百分比(RVPDF)、延迟射血血流百分数(RVPDEF)、滞留流入血流百分数(RVPRI)和残余血流百分数(RVPRVo)。用Spearman方法分析右心室血流与心室功能参数及血流动力学相关性。结果PH患者RVPDF、RVPDEF、RVPRI和RVPRVo分别为16.4%±9.2%、16.1%±5.6%、16.8%±6.1%和50.5%±12.3%。RVPDF与RVPRVo呈负相关(r=-0.703,P<0.001),而RVPDEF与RVPRI呈正相关(r=0.955,P<0.001)。RVPDF与右心室每搏输出量指数(RVSVI)(r=0.38,P=0.041)和右心室射血分数(RVEF)(r=0.69,P<0.001)呈正相关,与右心室收缩末期容积指数(RVESVI)(r=-0.65,P<0.001)及右心室心肌质量指数(RVMI)(r=-0.45,P=0.004)呈负相关。RVPRVo与RVEF(r=-0.58,P=0.007)呈负相关。RVPDF与RVPDEF之和(RVPDF+RVPDEF)为35.2%±11.4%,RVEF与(RVPDF+RVPDEF)呈正相关(r=0.825,P<0.001),且RVEF与RVPDF+RVPDEF之和间差异无计学意义(t=1.427,P=0.164)。RVPDF与肺血管阻力(PVR)呈负相关(r=-0.52,P=0.007),而RVPRVo与PVR呈正相关(r=0.54,P=0.004)。结论4D-FLOW CMR能够在自由呼吸状态下测定PH患者RVEF。PH患者右心室直接血流减低,而残余血流增多,且右心室直接血流及残余血流与右心室功能、PVR相关,是评价右心室功能及后负荷的重要指标。

Objective To investigatethe relationship between right ventricular blood flow components and right ventricular function in patients with pulmonary hypertension(PH)by 4D-FLOW cardiovascular MR(4D-FLOW CMR).Methods Thirty patients with PH were prospectively enrolled in this study.All patients underwent right heart catheterization to measure hemodynamics and CMR to measure right ventricular blood flow and right ventricular function within 1 week.The long-axis 4-chamber and contiguous short axis cineslices were acquired with balanced steady-state free precession sequence to calculate RV functional metrics including right ventricular end diastolic volume,end systolic volume,ejection fraction,stroke output and other functional parameters.Ventricular flow was acquired in sagittal direction,using a 3D retrospectively ECG-triggered,navigator-gated prototype sequence to analyze.RV function and flow parameters were correlated with Spearman correlation analysis.Results Right ventricular percent of direction flow(RVPDF),percent of delayed eject flow(RVPDEF),percent of retained flow(RVPRI)and percent of residual volume(RVPRV)of PH patients measured with 4D-FLOW were 16.4%±9.2%,16.1%±5.6%,16.8%±6.1%,and 50.5%±12.3%,respectively.RVPDF negatively correlated with RVPRVo(r=-0.703,P<0.001)while RVPDEF positively correlated with RVPRI(r=0.955,P<0.001).RVPDF was positively correlated with right ventricular stroke volume index(RVSVI)(r=0.38,P=0.041)and right ventricular eject fraction(RVEF)(r=0.69,P<0.001),and negatively correlated with right ventricular end systolic volume index(RVESVI)(r=-0.65,P<0.001)and right ventricular mass index(RVMI)(r=-0.45,P=0.004).RVPRVo was negatively correlated with RVEF(r=-0.58,P=0.007).The sum of RVPDF and RVPDEF(RVPDF+RVPDEF)was 35.2%±11.4%.RVEF correlated with RVPDF+RVPDEF(r=0.825,P<0.001)and comparable to RVPDF+RVPDEF(t=1.427,P=0.164).RVPDF was negatively correlated with pulmonary vascular resistance(PVR)(r=-0.52,P=0.007)while RVPRVo was positively correlated with PVR(r=0.54,P=0.004).Conclusions 4D-FLOW CMR can be used to measure right ventricular ejection fraction in PH patients without respiratory control.In PH patients,the right ventricular direct blood flow was significantly decreased,while the residual blood flow was significantly increased.The right ventricular direct blood flow and residual blood flow were related to the right ventricular function and pulmonary vascular resistance,which were important parameters to evaluate the right ventricular function and afterload in PH.