Pulmonary Arterial Hypertension: Likelihood Ratios

Introduction: Pulmonary hypertension that is a primary problem of the pulmonary arteries, also known as primary or idiopathic pulmonary hypertension. It is defined as:

Mean pulmonary artery pressure (mPAP) >25 mmHg at rest

Pulmonary capillary wedge pressure (PCWP) <15 mmHg

(Often instead of mPAP, RVSP is used with a cutoff of 40mmHg being suggestive but not diagnostic of PAH.)

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The likelihood ratios of findings for Pulmonary Arterial Hypertension are listed below. See the left navigation bar to change the display.

Pre-Test Probability (Prevalence): %.	Post-Test Probability (Predictive Value): %.	Switch to display mode.
Note that calculating probabilities from more than one** finding is inherently inaccurate because findings are not independent. (For example, using two positive findings that share a common pathogenesis is likely to overestimate the true probability.)

Good Positive and Negative Likelihood Ratios
Finding	Result	+LR	-LR
[ + ] Pulmonary Capillary Wedge Pressure	+ 0 -	7.1	0.4
PCWP <= 15 mmHg (which is in the definition), compared to LVEDP <= 15 mmHg as a 'gold standard' measurement of left-sided filling pressures. Another way of looking at this: in patients with PAH defined by PCWP<=15, 53% of them had an LVEDP > 15 mmHg. Study: Chest. 2009 Jul;136(1):37-43. PMID 19255293