mean pulmonary artery pressure

Blood pressure rises and falls with each heartbeat, like the tide swelling and ebbing. The mean pulmonary artery pressure is the single averaged value of the pressure in the pulmonary artery across the whole cardiac cycle, a steady number that captures the overall load in the lung circulation rather than its peaks and troughs.

This averaged pressure is the defining measurement for pulmonary hypertension. By current standards, a mean pulmonary artery pressure above the normal range, measured directly at right heart catheterization, is what establishes the diagnosis. The threshold has been revised over the years as understanding has improved, which is why older and newer references may quote slightly different cut-off values.

Knowing the mean pressure alone is not enough to classify the disease. Doctors combine it with other catheter measurements, such as the wedge pressure that reflects the left heart and the pulmonary vascular resistance, to work out whether the problem lies in the lung vessels themselves or is being driven backwards from the left side of the heart. That distinction shapes the entire treatment plan.