Measurement of total pulmonary arterial compliance using invasive pressure monitoring and MR flow quantification during MR-guided cardiac catheterization

Abstract

Pulmonary hypertensive disease is assessed by quantification of pulmonary vascular resistance. Pulmonary total arterial compliance is also an indicator of pulmonary hypertensive disease. However, because of difficulties in measuring compliance, it is rarely used. We describe a method of measuring pulmonary arterial compliance utilizing magnetic resonance (MR) flow data and invasive pressure measurements. Seventeen patients with suspected pulmonary hypertension or congenital heart disease requiring preoperative assessment underwent MR-guided cardiac catheterization. Invasive manometry was used to measure pulmonary arterial pressure, and phase-contrast MR was used to measure flow at baseline and at 20 ppm nitric oxide (NO). Total arterial compliance was calculated using the pulse pressure method (parameter optimization of the 2-element windkessel model) and the ratio of stroke volume to pulse pressure. There was good agreement between the two estimates of compliance (r = 0.98, P < 0.001). However, there was a systematic bias between the ratio of stroke volume to pulse pressure and the pulse pressure method (bias = 61%, upper level of agreement = 84%, lower level of agreement = 38%). In response to 20 ppm NO, there was a statistically significant fall in resistance, systolic pressure, and pulse pressure. In seven patients, total arterial compliance increased >10% in response to 20 ppm NO. As a population, the increase did not reach statistical significance. There was an inverse relation between compliance and resistance (r = 0.89, P < 0.001) and between compliance and mean pulmonary arterial pressure (r = 0.72, P < 0.001). We have demonstrated the feasibility of quantifying total arterial compliance using an MR method.

Pulmonary vascular resistance and compliance relationship in pulmonary hypertension

“…Indeed, SEGERS et al [46] first showed that SV/PApp overestimates total arterial compliance by 81% in pigs and 60% in dogs when total arterial compliance was calculated using the reference method, namely the pulse pressure method. Similarly, MUTHURANGU et al [47] also reported that SV/PApp overestimates total arterial compliance by 61% in patients with suspected PH or congenital heart disease. As a result, authors initially warned against the use of the SV/PApp ratio as an estimate of total arterial compliance [7,33].…”

“…Given that SV exceeds the reservoir volume of the compliant pulmonary arteries, previous studies have documented that the SV/PApp ratio may significantly overestimate total arterial compliance [46,47]. Indeed, SEGERS et al [46] first showed that SV/PApp overestimates total arterial compliance by 81% in pigs and 60% in dogs when total arterial compliance was calculated using the reference method, namely the pulse pressure method.…”

“…Similarly, SV/PApp may also overestimate total arterial compliance when SV exceeds the Windkessel reservoir volume [44,46,47]. Finally, some studies have used total pulmonary resistance as an estimation of PVR, implying that Pzf is 0 mmHg.…”

Boundary conditions of patient-specific fluid dynamics modelling of cavopulmonary connections: possible adaptation of pulmonary resistances results in a critical issue for a virtual surgical planning

“…, [17]). Of note is the fact that, in the present study, the LPA and RPA boundaries were located before pulmonary artery branching, resulting in what may be seen as a simpler geometry than that used by other authors who considered multi-branched Fontan models [5,24].…”

Toward Patient-Specific Myocardial Models of the Heart

“…The authors use a three-element Windkessel model to compute the arterial pressures from the arterial flow. Windkessel models are derived from electrical circuit analogies, where current and voltage represent arterial flow and pressure, respectively, and have been found to represent well (after proper adjustment of the parameters) the clinical measurements [56][57][58]. To hold the mesh in space, the authors simulate the fibrous structure around the valves with springs, having one extremity attached to a basal node and the other extremity attached to a fixed point.…”