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