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Abstract：
BACKGROUND: Pulmonary transit time (PTT) can be measured automatically from arterial input function (AIF) images of dual sequence first-pass perfusion imaging. PTT has been validated against invasive cardiac catheterisation correlating with both cardiac output and left ventricular filling pressure (both important prognostic markers in heart failure). We hypothesized that prolonged PTT is associated with clinical outcomes in patients with heart failure.
METHODS: We recruited outpatients with a recent diagnosis of non-ischaemic heart failure with left ventricular ejection fraction (LVEF) < 50% on referral echocardiogram. Patients were followed up by a review of medical records for major adverse cardiovascular events (MACE) defined as all-cause mortality, heart failure hospitalization, ventricular arrhythmia, stroke or myocardial infarction. PTT was measured automatically from low-resolution AIF dynamic series of both the LV and RV during rest perfusion imaging, and the PTT was measured as the time (in seconds) between the centroid of the left (LV) and right ventricle (RV) indicator dilution curves.
RESULTS: Patients (N = 294) were followed-up for median 2.0 years during which 37 patients (12.6%) had at least one MACE event. On univariate Cox regression analysis there was a significant association between PTT and MACE (Hazard ratio (HR) 1.16, 95% confidence interval (CI) 1.08-1.25, P = 0.0001). There was also significant association between PTT and heart failure hospitalisation (HR 1.15, 95% CI 1.02-1.29, P = 0.02) and moderate correlation between PTT and N-terminal pro B-type natriuretic peptide (NT-proBNP, r = 0.51, P < 0.001). PTT remained predictive of MACE after adjustment for clinical and imaging factors but was no longer significant once adjusted for NT-proBNP.
CONCLUSIONS: PTT measured automatically during CMR perfusion imaging in patients with recent onset non-ischaemic heart failure is predictive of MACE and in particular heart failure hospitalisation. PTT derived in this way may be a non-invasive marker of haemodynamic congestion in heart failure and future studies are required to establish if prolonged PTT identifies those who may warrant closer follow-up or medicine optimisation to reduce the risk of future adverse events.
METHODS: We recruited outpatients with a recent diagnosis of non-ischaemic heart failure with left ventricular ejection fraction (LVEF) < 50% on referral echocardiogram. Patients were followed up by a review of medical records for major adverse cardiovascular events (MACE) defined as all-cause mortality, heart failure hospitalization, ventricular arrhythmia, stroke or myocardial infarction. PTT was measured automatically from low-resolution AIF dynamic series of both the LV and RV during rest perfusion imaging, and the PTT was measured as the time (in seconds) between the centroid of the left (LV) and right ventricle (RV) indicator dilution curves.
RESULTS: Patients (N = 294) were followed-up for median 2.0 years during which 37 patients (12.6%) had at least one MACE event. On univariate Cox regression analysis there was a significant association between PTT and MACE (Hazard ratio (HR) 1.16, 95% confidence interval (CI) 1.08-1.25, P = 0.0001). There was also significant association between PTT and heart failure hospitalisation (HR 1.15, 95% CI 1.02-1.29, P = 0.02) and moderate correlation between PTT and N-terminal pro B-type natriuretic peptide (NT-proBNP, r = 0.51, P < 0.001). PTT remained predictive of MACE after adjustment for clinical and imaging factors but was no longer significant once adjusted for NT-proBNP.
CONCLUSIONS: PTT measured automatically during CMR perfusion imaging in patients with recent onset non-ischaemic heart failure is predictive of MACE and in particular heart failure hospitalisation. PTT derived in this way may be a non-invasive marker of haemodynamic congestion in heart failure and future studies are required to establish if prolonged PTT identifies those who may warrant closer follow-up or medicine optimisation to reduce the risk of future adverse events.
摘要：
背景：可以从双序列首过灌注成像的动脉输入功能（AIF）图像中自动测量肺传输时间（PTT）。PTT已针对与心输出量和左心室充盈压（心力衰竭的重要预后标志物）相关的侵入性心导管插入进行了验证。我们假设延长的PTT与心力衰竭患者的临床结果相关。
方法：我们招募了最近诊断为非缺血性心力衰竭的患者，其左心室射血分数（LVEF）<50％。随访患者的主要不良心血管事件（MACE）定义为全因死亡率的医疗记录，心力衰竭住院，室性心律失常,中风或心肌梗塞。在静息灌注成像期间,根据LV和RV的低分辨率AIF动态系列自动测量PTT。并且将PTT测量为左(LV)和右心室(RV)指示物稀释曲线的质心之间的时间(以秒为单位)。
结果：对患者（N=294）进行了中位2.0年的随访，其中37例患者（12.6%）发生了至少一次MACE事件。在单变量Cox回归分析中，PTT与MACE之间存在显着关联（危险比（HR）1.16，95％置信区间（CI）1.08-1.25，P=0.0001）。PTT与心力衰竭住院之间也存在显着相关性（HR1.15，95％CI1.02-1.29，P=0.02），PTT与N末端B型利钠肽前体之间存在中度相关性（NT-proBNP，r=0.51,P<0.001)。调整临床和影像学因素后，PTT仍可预测MACE，但一旦调整NT-proBNP，则不再显着。
结论：在近期发作的非缺血性心力衰竭患者的CMR灌注成像期间自动测量PTT可预测MACE，尤其是心力衰竭住院。以这种方式获得的PTT可能是心力衰竭中血液动力学充血的非侵入性标志物，并且需要进一步的研究来确定是否延长的PTT识别出可能需要更密切的随访或药物优化以降低未来不良事件的风险的那些人。
方法：我们招募了最近诊断为非缺血性心力衰竭的患者，其左心室射血分数（LVEF）<50％。随访患者的主要不良心血管事件（MACE）定义为全因死亡率的医疗记录，心力衰竭住院，室性心律失常,中风或心肌梗塞。在静息灌注成像期间,根据LV和RV的低分辨率AIF动态系列自动测量PTT。并且将PTT测量为左(LV)和右心室(RV)指示物稀释曲线的质心之间的时间(以秒为单位)。
结果：对患者（N=294）进行了中位2.0年的随访，其中37例患者（12.6%）发生了至少一次MACE事件。在单变量Cox回归分析中，PTT与MACE之间存在显着关联（危险比（HR）1.16，95％置信区间（CI）1.08-1.25，P=0.0001）。PTT与心力衰竭住院之间也存在显着相关性（HR1.15，95％CI1.02-1.29，P=0.02），PTT与N末端B型利钠肽前体之间存在中度相关性（NT-proBNP，r=0.51,P<0.001)。调整临床和影像学因素后，PTT仍可预测MACE，但一旦调整NT-proBNP，则不再显着。
结论：在近期发作的非缺血性心力衰竭患者的CMR灌注成像期间自动测量PTT可预测MACE，尤其是心力衰竭住院。以这种方式获得的PTT可能是心力衰竭中血液动力学充血的非侵入性标志物，并且需要进一步的研究来确定是否延长的PTT识别出可能需要更密切的随访或药物优化以降低未来不良事件的风险的那些人。
