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专家一致认为,需要对肺循环的刺激试验进行标准化http://ow.ly/4nsNbU
在的这个问题欧洲呼吸杂志,O-liveira等。[1来自哈佛医学院(波士顿,MA,USA)后的最大增量骑自行车运动肺血管压力的迅速恢复报告。作者结合右心脏导管插入术与中提到的不明原因的呼吸困难95例并发心肺运动试验。36patients had precapillary pulmonary hypertension (PH) during exercise, defined by the authors as displaying a peak exercise mean pulmonary artery pressure (mPAP) ≥30 mmHg, a peak wedged pulmonary artery pressure (PAWP) <20 mmHg and a peak pulmonary vascular resistance (PVR) ≥1.5 Wood units (WU). 28 patients had postcapillary PH during exercise defined by a peak PAWP ≥20 mmHg. 31 matched controls with normal resting mPAP were selected based on a maximum oxygen uptake ≥80% predicted in the absence of exercise PH based on the aforementioned criteria. Workload and oxygen uptake at the ventilatory threshold and at peak exercise were lower in the exercise PH patients, which confirm the relevance of exercise pulmonary haemodynamic measurements in unexplained dyspnoea. However, most of the exercise-induced increase in PAWP and mPAP was reversed within 2 min of recovery. The important message is that pulmonary haemodynamics have to be measured during, but not after, an exercise stress test for the diagnosis of exercise PH.
挑衅性测试被用于医学的许多领域,以揭示早期病理。然而,对于早期或潜在PH值,专家们仍然十分谨慎。2013年在法国尼斯举行的上一届世界研讨会的报告和指南指出,不鼓励进行压力测试或肺循环容积负荷,因为没有足够的证据表明正常和预后或治疗影响的限度[2,3]。然而这种做法在心导管插入术的早期就已经存在了[4]和显著的进步,近年来已取得[五]。
It is now well established that the upper limit of normal of mPAP during exercise is 30 mmHg at a cardiac output (CO) <10 L·min-1,相当于总肺血管阻力(TPR)(或mPAP/CO)为3 WU [五-9]。有意义的非侵入式测量正在由专门的小组报道[五-7]。此外,有证据正在收集,除运动时正常肺动脉压力较高可能是其他原因不明的呼吸困难的原因,可以促进PH的早期诊断继发于呼吸道或左心脏条件[6,7]。
锻炼PH的原因或者是增加PAWP的上游传输,诸如在具有保持的或降低的喷射和左心脏瓣膜症,或增加PVR,例如在肺血管疾病,缺氧或扰乱肺力学[心脏衰竭4-8]。这个鉴别诊断常常在临床上是简单的,但是精确的测量和PAWP的解释或左心室舒张末期压力测量是至关重要的。The upper limit of normal of PAWP during exercise is generally thought to be between 15 and 20 mmHg but higher values can be recorded in athletes and in elderly subjects [10]。Øliveira等。[1认为20毫米汞柱是正常的合理上限。然而,25 mmHg被认为是诊断心力衰竭的较高临界值[11,12]。同样地,对于大鼠mPAP,流校正的度量可以是更合适的。由于TPR行使最高时下降到25%[10], it is easy to predict normal PAWP/CO slopes of <2 mmHg·L-1·敏-1。这确实被测量,但在有限的尺寸健康对照组[11-13]。
有趣的是,其中Oliveira等。[1] consider PVR instead of TPR combined to increased pulmonary artery pressure in the diagnosis of exercise PH and actually retain a cut-off value of 1.5 WU [1]。This PVR cut-off seems low, since a significant proportion of patients based on these criteria may not exceed a mPAP >30 mmHg together with TPR >3 WU during exercise. Definitions of PH have traditionally incorporated a “safety margin” to decrease the prevalence of false positives due to healthy outliers and lack of precision of measurements. This is why PH is defined by a mPAP >25 mmHg at rest, while the upper limit of normal is 20 mmHg. One still does not know if a mPAP >30 mmHg at a CO <10 L·min-1,corresponding to a TPR of 3 WU is enough to minimise false positives across different ethnic populations and age groups. Conversely, the incorporation of a safety margin may also increase the likelihood of false-negative cases. In other words, any diagnostic thresholds assume a trade-off between sensitivity and specificity. For example, there was a recent noninvasive study showing higher exercise TPR values between 3 and 3.5 WU encountered in healthy sub-Saharan black African males [14]。一种n exercise TPR slightly above 3 WU is also sometimes measured in invasively explored European healthy controls [8]。
运动过程中肺动脉压和PAWP的测量在技术上具有挑战性并通过胸内压波动是复杂的[15]。因此,建议在几个呼吸周期中对肺血管压力曲线的读数取平均值,而不是仅在呼气末[2]。这实际上是被O完成liveira等。[1]和心脏病准则最近更新的欧洲呼吸协会/欧洲社会认同[188bet官网地址3]。然而,关于何时从一种方法转换到另一种方法,以及这与症状和结果的相关性如何,仍然存在疑问。
肺循环的另一日益流行的压力测试是流体加载,这是主要用于检测左心脏疾病潜肺静脉高压。因此,具有改变的左心室舒张期顺应性或二尖瓣狭窄相关的任何病症将与当用激发在PAWP的快速增加相关联增加全身静脉回流[16]。这里也有许多关于如何规范流体的挑战和什么切断了PAWP考虑价值观问题。流体装载在健康志愿者中增加PAWP如年龄,性别,注入量和输液速度的函数[17]。While there is an emerging consensus to infuse 500 mL of saline in 5–10 min, some groups consider a PAWP of 15 mmHg as a reasonable cut-off for a pathological response [18,19]。然而,现有的数据进行重新分析聚集在健康受试者和积累的临床经验[20.] is drifting this cut-off value to 20 mmHg. It should not be overlooked that exercise increases systemic venous return as well. However, exercise may be more sensitive than volume loading to detect early pulmonary venous hypertension in patients with heart failure with preserved ejection fraction [21]。
我们将何去何从?O的报告liveira等。[1这是标准的右室-肺循环刺激试验的重要一步,但仍有许多工作要做。虽然人们希望一致认为,任何测试都需要在强调相关系统的情况下进行测量,但还有一系列其他方法问题需要专家达成一致意见进行标准化。其中之一可能是身体姿势,因为一些运动测试是让受试者坐在自行车上进行的,另一些测试是让受试者坐在倾斜的扶手椅上进行超声心动图检查,还有一些测试是让受试者躺在导尿试验台的横卧位置上进行的。体位肯定会影响肺静息血流动力学,因为直立姿势与肺血管脱位和全身静脉回流减少有关。然而,在运动测量中,身体位置可能不那么重要,但是需要更多的数据。运动方式也很重要,因为阻力成分可能与全身血管阻力的增加或Valsalva演习时胸内压的增加有关,所有这些都直接或间接地影响肺血管压力。有些中心将mPAP视为工作量的函数,而工作量与CO呈线性相关,但不能作为替代,因为CO对给定工作量的响应范围有相当大的差异[22]。最紧迫的问题之一是呼气末与平均读数肺血管压力曲线。最后但并非最不重要的,有需要的非侵入性方法的详细验证,心导管通常不能用于筛选或症状轻微的患者发现早期疾病。
在此期间,O-liveira等。[1]被到会祝贺与极其困难的实验,结合心导管和运动试验向前迈进。有趣的是,仍然有这么多的生理问题,以解决不同形式的PH更好地理解和早期诊断和同事准备卷起袖子解决仍然悬而未决的方法问题。没有医学的进步可能没有无可争议的方法。
脚注
利益冲突:无申报。
- 收到了2016年4月30日。
- 公认2016年5月3日。
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