Left Ventricular and Aortic Pressures Measured With Fluid-Filled and Solid-State Pressure Catheters: Similarities and Differences

Objective: To compare left ventricular (LV) and aortic (AO) pressures obtained using fluid-filled and high-fidelity solid-state pressure catheters in subjects undergoing left heart catheterization.

Materials and Methods: Twenty subjects scheduled for a left heart catheterization were enrolled and 18 subjects completed this IRB-approved study. LV and AO pressures were obtained using fluid-filled pressure catheter (standard-of-care) and high-fidelity solid-state pressure catheter synchronously. Pressure tracings were analyzed to measure LV systolic (LVSP), LV minimum-diastolic (LVMDP), LV end-diastolic (LVEDP), AO systolic (AOSP), and AO diastolic (AODP) pressures. Isovolumic contraction and relaxation rates (peak ± dp/dt) were derived from the pressure waveforms. Repeated measures of variance, post hoc tests with Bonferroni corrections, and Bland–Altman plots were used for comparisons.

Results: A significant main effect of the pressure catheter was noted for LVSP, LVMDP, and AOSP (p ≤ 0.025). The LVSP and AOSP measured with fluid-filled pressure catheters were higher by 6.6 ± 6.9 mmHg and 4.6 ± 5.2 mmHg in comparison to solid-state pressure catheter. In contrast, the LVMDP measurements were 3.5 ± 5.7 mmHg lower than the solid-state pressure catheter measurements. The isovolumic contraction (66.4 ± 116.0 mmHg/s) and relaxation rates (60.5 ± 113.5 mmHg/s) were not significantly different between catheter systems after Bonferroni corrections for multiple comparisons (p ≥ 0.06). The Bland–Altman analysis revealed a bias ranging from 0.8 to 6.6 mmHg.

Conclusions: Differences in LVSP, LVMDP, and AOSP were noted between the catheter systems but not for other pressure values and contraction/relaxation rates. Fluid-filled catheters overestimated true systolic pressures in the left ventricle and aorta.

Trial Registration: ClinicalTrials.gov identifier: NCT03245255