An arterial-ventricular interaction model accurately reproduced experimentally derived proportional relations between systolic and mean pulmonary artery pressure (simulated ratio 1.55 vs experimental 1.59), demonstrating these relations result from a constant RC-time.
Observational (n=109)
No
The proportional relationships between systolic, diastolic, and mean pulmonary artery pressures are universally maintained due to the constant RC-time of the pulmonary arterial system, with minimal influence from heart rate.
Absolute Event Rate: 1.55% vs 1.59%
Recently, it was shown that proportional relationships exist between systolic, diastolic and mean pulmonary artery pressure (P sys, P dia and P mean) and that they are maintained under various conditions in both health and disease. An arterial-ventricular interaction model was used to study the contribution of model parameters to the ratios P sys/P mean, and P dia/P mean. The heart was modeled by a time-varying elastance function, and the arterial system by a three-element windkessel model consisting of peripheral resistance, R p, arterial compliance C a, and pulmonary artery characteristic impedance Z 0. Baseline model parameters were estimated in control subjects and compared to values estimated in patients with pulmonary hypertension. Results indicate that experimentally derived ratios P sys/P mean and P dia/P mean could be accurately reproduced using our model (1.59 and 0.61 vs. 1.55 and 0.64, respectively). Sensitivity analysis showed that the (empirical) constancy of P sys/P mean and P dia/P mean was primarily based on the inverse hyperbolic relation between total vascular resistance (R T; calculated as R p + Z 0) and C a, (i.e. constant R T C a product). Of the cardiac parameters, only heart rate affected the pressure ratios, but the contribution was small. Therefore, we conclude that proportional relations between systolic, diastolic and mean pulmonary artery pressure result from the constancy of R T C a thus from pulmonary arterial properties, with only little influence of heart rate.
Kind et al. (2010) conducted an observational in Pulmonary arterial hypertension (n=109). Arterial-ventricular interaction model vs. Experimental clinical data was evaluated on Ratio Ksys (Psys/Pmean). An arterial-ventricular interaction model accurately reproduced experimentally derived proportional relations between systolic and mean pulmonary artery pressure (simulated ratio 1.55 vs experimental 1.59), demonstrating these relations result from a constant RC-time.
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