Relationship between myocardial oxygenation and blood pressure: Experimental validation using oxygenation-sensitive cardiovascular magnetic resonance
Relationship between myocardial oxygenation and blood pressure: Experimental validation using oxygenation-sensitive cardiovascular magnetic resonance
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DOI：
10.1371/journal.pone.0210098
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发表时间：
2019-01-16
期刊：
影响因子：
3.7
通讯作者：
Eberle, Balthasar
中科院分区：
文献类型：
--
作者：
Guensch, Dominik P.;Fischer, Kady;Eberle, Balthasar
背景平均动脉压（MAP）与冠状动脉血流量的关系已被广泛研究。在60至140 mmHg的MAP范围内存在自动调节，提供接近恒定的冠状动脉血流。在这些极限之外，流量变得依赖于压力。到目前为止，心肌氧合对压力和流量变化的反应更难评估。虽然已建立的技术大多需要侵入性方法，但氧合敏感（OS）心血管磁共振（CMR）是一种可以无创评估心肌组织氧合变化的技术。本研究的目的是使用OS-CMR在已知的冠状动脉自动调节限值内和限值外的大范围血压变化范围内跟踪心肌氧合，并将这些数据与冠状动脉血流动力学联系起来。（德国大白色）接受左侧开胸术，并将血管周围血流探针连接到近端左前降支（LAD）冠状动脉，以连续测量血流（QLAD）。此后，将动物转移到3 T MRI扫描仪中。平均动脉压（MAP）变化在10-15毫米汞柱的步骤，通过管理α 1-受体药物苯肾上腺素或乌拉地尔。对于每个MAP水平，在短暂的呼吸暂停期间同时获得OS-CMR图像以及动脉和冠状窦血气样本。冠状窦氧饱和度（ScsO（2））、氧输送（DO 2）和氧需求（MVO 2）的相对变化（Delta），在MAP为70 mmHg时，测定各参考水平的提取率（O2 ER）和过量（Omega），并与同时采集的OS-CMR图像中的OS信号强度（OS-SI）变化%进行比较。反应表明MAP水平在52 mmHg（下限）和127 mmHg（上限）之间自动调节。OS-CMR显示在低于自动调节下限时出现整体心肌氧合不足，OS-SI的最低值为-9.0%。MAP值超过70 mmHg时，相对OS-SI增加至最大值+10.6%。与此一致，Delta ScsO（2）、Delta DO 2、Delta MVO 2、Delta O2 ER和Delta Omega响应表明自动调节区外氧合平衡的不匹配增加。总体OS-CMR的变化与所有这些参数显著相关（p
BackgroundThe relationship between mean arterial pressure (MAP) and coronary blood flow is well described. There is autoregulation within a MAP range of 60 to 140 mmHg providing near constant coronary blood flow. Outside these limits flow becomes pressure-dependent. So far, response of myocardial oxygenation to changes in pressure and flow has been more difficult to assess. While established techniques mostly require invasive approaches, Oxygenation-Sensitive (OS) Cardiovascular Magnetic Resonance (CMR) is a technique that can non-invasively assess changes in myocardial tissue oxygenation. The purpose of this study was to follow myocardial oxygenation over a wide range of blood pressure variation within and outside known coronary autoregulatory limits using OS-CMR, and to relate these data to coronary hemodynamics.MethodsTen anaesthetized swine (German Large White) underwent left-sided thoracotomy and attachment of a perivascular flow probe to the proximal left anterior descending (LAD) coronary artery for continuous measurement of blood flow (QLAD). Thereafter, animals were transferred into a 3T MRI scanner. Mean arterial pressure (MAP) was varied in 10-15 mmHg steps by administering alpha1-receptor agents phenylephrine or urapidil. For each MAP level, OS-CMR images as well as arterial and coronary sinus blood gas samples were obtained simultaneously during brief periods of apnea. Relative changes (Delta) of coronary sinus oxygen saturation (ScsO(2)), oxygen delivery (DO2) and demand (MVO2), extraction ratio (O2ER) and excess (Omega) from respective reference levels at a MAP of 70 mmHg were determined and were compared to % change in OS-signal intensity (OS-SI) in simultaneously acquired OS-CMR images.ResultsQ(LAD) response indicated autoregulation between MAP levels of 52 mmHg ( lower limit) and127 mmHg ( upper limit). OS-CMR revealed a global myocardial oxygenation deficit occurring below the lower autoregulation limit, with the nadir of OS-SI at -9.0%. With MAP values surpassing 70 mmHg, relative OS-SI increased to a maximum of +10.6%. Consistent with this, Delta ScsO(2), Delta DO2, Delta MVO2, Delta O2ER and Delta Omega responses indicated increasing mismatch of oxygenation balance outside the autoregulated zone. Changes in global OS-CMR were significantly correlated with all of these parameters ( p