Researchers Identify Golden Ratio Between Pulmonary Pressure Components in PAH

heart and lungs diagram
heart and lungs diagram
In untreated patients with pulmonary arterial hypertension and in controls, the fluctuations in systolic pulmonary artery pressure (PAP) and diastolic PAP around mean PAP exhibited constant scaling factor shown to be the golden ratio.

Fluctuations in systolic pulmonary artery pressure (sPAP) and diastolic PAP (dPAP) around mean PAP (mPAP) have a scaling factor consistent with the golden ratio (Phi, Φ = 1.618) in patients with untreated pulmonary arterial hypertension (PAH) and in controls. This finding was reported in a study published in Chest.

Researchers retrospectively analyzed fluid-filled pressure data of 981 untreated participants with idiopathic, heritable or drug-induced PAH who were enrolled in the French Pulmonary Arterial Hypertension Network registry.

A total of 44 controls with an mPAP ≤20 mmHg were tested for the “hypothesis that the systolic over mean pulmonary artery pressure ratio (sPAP/mPAP) and the mean over diastolic pressure ratio (mPAP/dPAP) may match Φ in patients with pulmonary arterial hypertension (PAH) and in controls.” The test was performed using high-fidelity pressure catheters and included controls from a systematic review of 5 studies.

The respective median values of sPAP/mPAP and mPAP/dPAP in patients with PAH were 1.591 (98%Φ) and 1.559 (96%Φ). Comparatively, the mean values of sPAP/dPAP and mPAP/dPAP were 1.572 (97%Φ) and 1.470 (91%Φ) in controls. A weak but negative association was observed between sPAP/mPAP and mPAP/dPAP ratios with mPAP (rho = –0.23 and –0.21, respectively; P <.01). According to the researchers, these findings were consistent with their Φ hypothesis with the assumption <1 mmHg estimation error of sPAP, mPAP and dPAP.

A limitation of the study was that many different forms of PH, including chronic thromboembolic PH and postcapillary PH, were not studied.

Findings from this analysis, according to the study’s researchers, “may offer a new framework to describe the components of PA pressure based on the golden ratio, one of the ‘most astonishing numbers.’”

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Chemla D, Boulate D, Weatherald J, et al. Golden ratio and the proportionality between pulmonary pressure components in pulmonary arterial hypertension [published online December 27, 2018]. Chest. doi: 10.1016/j.chest.2018.12.006