同时实时心血管磁共振和左心导管术的动态压力-容积环分析。
Dynamic pressure-volume loop analysis by simultaneous real-time cardiovascular magnetic resonance and left heart catheterization.
机构信息
Cardiovascular Branch, Division of Intramural Research, National Heart, Lung, and Blood, Institute, National Institutes of Health, 10 Center Drive, Building 10 Rm B1D47, Bethesda, MD, 20892, USA.
Instrumentation Development and Engineering Application Solutions, Division of Intramural Research, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD, 20892, USA.
出版信息
J Cardiovasc Magn Reson. 2023 Jan 16;25(1):1. doi: 10.1186/s12968-023-00913-4.
BACKGROUND
Left ventricular (LV) contractility and compliance are derived from pressure-volume (PV) loops during dynamic preload reduction, but reliable simultaneous measurements of pressure and volume are challenging with current technologies. We have developed a method to quantify contractility and compliance from PV loops during a dynamic preload reduction using simultaneous measurements of volume from real-time cardiovascular magnetic resonance (CMR) and invasive LV pressures with CMR-specific signal conditioning.
METHODS
Dynamic PV loops were derived in 16 swine (n = 7 naïve, n = 6 with aortic banding to increase afterload, n = 3 with ischemic cardiomyopathy) while occluding the inferior vena cava (IVC). Occlusion was performed simultaneously with the acquisition of dynamic LV volume from long-axis real-time CMR at 0.55 T, and recordings of invasive LV and aortic pressures, electrocardiogram, and CMR gradient waveforms. PV loops were derived by synchronizing pressure and volume measurements. Linear regression of end-systolic- and end-diastolic- pressure-volume relationships enabled calculation of contractility. PV loops measurements in the CMR environment were compared to conductance PV loop catheter measurements in 5 animals. Long-axis 2D LV volumes were validated with short-axis-stack images.
RESULTS
Simultaneous PV acquisition during IVC-occlusion was feasible. The cardiomyopathy model measured lower contractility (0.2 ± 0.1 mmHg/ml vs 0.6 ± 0.2 mmHg/ml) and increased compliance (12.0 ± 2.1 ml/mmHg vs 4.9 ± 1.1 ml/mmHg) compared to naïve animals. The pressure gradient across the aortic band was not clinically significant (10 ± 6 mmHg). Correspondingly, no differences were found between the naïve and banded pigs. Long-axis and short-axis LV volumes agreed well (difference 8.2 ± 14.5 ml at end-diastole, -2.8 ± 6.5 ml at end-systole). Agreement in contractility and compliance derived from conductance PV loop catheters and in the CMR environment was modest (intraclass correlation coefficient 0.56 and 0.44, respectively).
CONCLUSIONS
Dynamic PV loops during a real-time CMR-guided preload reduction can be used to derive quantitative metrics of contractility and compliance, and provided more reliable volumetric measurements than conductance PV loop catheters.
背景
左心室（LV）收缩性和顺应性是通过动态前负荷降低过程中的压力-容积（PV）环得出的，但目前的技术在可靠地同时测量压力和容积方面存在挑战。我们已经开发出一种方法，通过使用实时心血管磁共振（CMR）和 CMR 特定信号调节的侵入性 LV 压力同时测量容积，从动态前负荷降低过程中的 PV 环中量化收缩性和顺应性。
方法
在 16 头猪（n=7 头为对照，n=6 头主动脉缩窄以增加后负荷，n=3 头缺血性心肌病）中，在下腔静脉（IVC）闭塞的同时进行动态 PV 环的推导。闭塞与实时 CMR 长轴的动态 LV 容积采集同时进行，以 0.55T 进行，记录侵入性 LV 和主动脉压力、心电图和 CMR 梯度波形。PV 环通过同步压力和容积测量得出。通过对收缩末期和舒张末期压力-容积关系进行线性回归，计算收缩性。在 5 只动物中，将 CMR 环境中的 PV 环测量值与导引导管 PV 环测量值进行比较。使用短轴堆叠图像验证 LV 长轴 2D 容积。
结果
在 IVC 闭塞期间进行同时的 PV 采集是可行的。与对照动物相比，心肌病模型的收缩性较低（0.2±0.1mmHg/ml 与 0.6±0.2mmHg/ml），顺应性较高（12.0±2.1ml/mmHg 与 4.9±1.1ml/mmHg）。主动脉缩窄处的压力梯度无临床意义（10±6mmHg）。相应地，在对照和缩窄的猪之间没有发现差异。LV 长轴和短轴容积之间的一致性较好（舒张末期差异 8.2±14.5ml，收缩末期差异-2.8±6.5ml）。导引导管和 CMR 环境中得出的收缩性和顺应性的一致性适中（组内相关系数分别为 0.56 和 0.44）。
结论
实时 CMR 引导下前负荷降低过程中的动态 PV 环可用于得出收缩性和顺应性的定量指标，并提供比导引导管 PV 环更可靠的容积测量。
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