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. 2022 Oct 13;60(4):2103181. doi: 10.1183/13993003.03181-2021

FIGURE 3.

FIGURE 3

Mean pulmonary arterial pressure (mPAP)/cardiac output (CO), pulmonary arterial wedge pressure (PAWP)/CO and trans-pulmonary gradient (TPG)/CO slopes for the characterisation of pulmonary haemodynamic parameters during exercise. Abnormal pulmonary haemodynamic parameters during exercise may be defined by an increased mPAP/CO slope. This slope is strongly age-dependent and its upper limit of normal (ULN) (mean+2sd) ranges from 1.6 Wood units (WU) (in ∼30-year-old healthy subjects) to 3.3 WU (in ∼70-year-old healthy subjects) in the supine position (table 2). The ULN based on the weighted mean and sd of all healthy subjects included in this analysis was 2.7 WU in the supine position. An increased mPAP/CO slope with a cut-off above >3 WU is independently associated with poor survival and heart failure-related hospitalisations. The mPAP/CO slope corresponds to the sum of the TPG/CO slope and the PAWP/CO slope. Like the mPAP/CO slope, the PAWP/CO slope is also strongly age-dependent and its ULN ranges from 0.6 to 1.8 WU. An increased PAWP/CO slope with a cut-off >2 WU is associated with impaired survival and increased cardiovascular (CV) events and may be diagnostic for a post-capillary cause of PAP elevation during exercise. The ULN for the TPG/CO slope is 1.2 WU and age-independent. An increased TPG/CO slope is also associated with impaired survival and may be suggestive of pulmonary vascular disease (PVD). Studies reporting on the prognostic relevance of the mPAP/CO, TPG/CO and PAWP/CO slopes are indicated in the footnotes. LHD: left heart disease. #: for validating mPAP/CO >3 WU cut-off [31], and [12, 42, 44, 45, 48]; : for validating mPAP/CO >3 WU cut-off [31]; +: [31, 48]; §: [31]; ƒ: [56, 57, 61–63]; ##: for validating PAWP/CO >2 WU cut-off [32], and [31, 33]; ¶¶: for validating PAWP/CO >2 WU cut-off [32], and [31]; ++: for validating PAWP/CO >2 WU cut-off [32], and [54].