Dept of Physiology, Faculty of Medicine, Free University Brussels, Brussels, Belgium.
Eur Respir J. 2013 Jan;41(1):217-23. doi: 10.1183/09031936.00074312. Epub 2012 Aug 30.
The transpulmonary pressure gradient (TPG), defined by the difference between mean pulmonary arterial pressure (P(pa)) and left atrial pressure (P(la); commonly estimated by pulmonary capillary wedge pressure: P(pcw)) has been recommended for the detection of intrinsic pulmonary vascular disease in left-heart conditions associated with increased pulmonary venous pressure. In these patients, a TPG of >12 mmHg would result in a diagnosis of "out of proportion" pulmonary hypertension. This value is arbitrary, because the gradient is sensitive to changes in cardiac output and both recruitment and distension of the pulmonary vessels, which decrease the upstream transmission of P(la). Furthermore, pulmonary blood flow is pulsatile, with systolic P(pa) and mean P(pa) determined by stroke volume and arterial compliance. It may, therefore, be preferable to rely on a gradient between diastolic P(pa) and P(pcw). The measurement of a diastolic P(pa)/P(pcw) gradient (DPG) combined with systemic blood pressure and cardiac output allows for a step-by-step differential diagnosis between pulmonary vascular disease, high output or high left-heart filling pressure state, and sepsis. The DPG is superior to the TPG for the diagnosis of "out of proportion" pulmonary hypertension.
肺跨压梯度（TPG）定义为平均肺动脉压（P（pa））与左心房压（P（la））之间的差异（通常通过肺毛细血管楔压估计：P（pcw）），用于检测与肺静脉压升高相关的左心疾病中的固有肺血管疾病。在这些患者中，TPG>12mmHg 将导致“不成比例”的肺动脉高压的诊断。该值是任意的，因为梯度对心输出量的变化以及肺血管的募集和扩张敏感，这会降低肺静脉压的上游传递。此外，肺血流是脉动的，收缩压 P（pa）和平均 P（pa）由每搏量和动脉顺应性决定。因此，可能更倾向于依赖舒张期 P（pa）和 P（pcw）之间的梯度。舒张期 P（pa）/P（pcw）梯度（DPG）与全身血压和心输出量的测量相结合，允许对肺血管疾病、高输出或高左心充盈压状态和败血症进行逐步鉴别诊断。DPG 比 TPG 更适合诊断“不成比例”的肺动脉高压。
