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Quantification of left ventricular diastolic pressure-volume relations during routine cardiac catheterization by
Stig Urheim1, Reidar Bjørnerheim, Knut Endresen
1Institute of Surgical Research, Rikshospitalet, Oslo, Norway.
Insights
This study shows that real-time left ventricular (LV) pressure-volume loops can be displayed using digital echo quantification (DEQ) and micromanometry during cardiac catheterization, aiding in identifying reduced LV chamber compliance.
Area of Science:
- Cardiology
- Medical Imaging
- Physiology
Background:
- Quantifying left ventricular (LV) diastolic pressure-volume relations lacks a simple clinical method.
- Echocardiography with automated endocardial border detection and LV micromanometry can construct LV pressure-volume loops.
- Digital echo quantification (DEQ) offers a novel approach for real-time LV pressure-volume loop analysis.
Purpose of the Study:
- To investigate the feasibility of on-line display and sampling of LV pressure-volume loops using DEQ combined with LV micromanometry.
- To assess the clinical utility of real-time LV pressure-volume loop display for evaluating diastolic function.
- To determine if this method can identify patients with reduced LV chamber compliance.
Main Methods:
- Eighteen patients were screened; ten with high-quality images were included.
- Left ventricular pressures and volumes were recorded simultaneously and displayed as real-time pressure-volume loops.
- LV chamber compliance was estimated using the change in volume divided by the change in pressure during diastole.
Main Results:
- Real-time LV pressure-volume loops were successfully displayed during cardiac catheterization.
- DEQ underestimated end-diastolic volume (EDV) by 35% and overestimated end-systolic volume (ESV) by 14% compared to Simpson's method.
- Volume loading decreased LV chamber compliance from 4.0 to 2.0 mL/mmHg (P < .05).
Conclusions:
- Real-time display of LV pressure-volume loops is feasible during routine cardiac catheterization.
- This technique may be clinically useful for identifying patients with reduced LV chamber compliance.
- Further refinement of the DEQ endocardial border detection algorithm is needed to improve volume accuracy.
Background:
Currently there is no simple clinical method for quantifying the left ventricular (LV) diastolic pressure-volume relation. Echocardiographic-automated endocardial border detection, however, may be combined with LV micromanometer to construct LV pressure-volume loops. We investigated the feasibility of on-line display and sampling of LV pressure-volume loops by such an approach. For this purpose we used a new echocardiographic digital echo quantification (DEQ) method in combination with LV pressures on-line and in real-time.
Methods:
Eighteen patients were screened by conventional echocardiography and DEQ. Ten of the patients with high quality images were included in the study. Left ventricular pressures and volumes were recorded simultaneously and were displayed on-line as pressure-volume loops. Changes in LV volume were induced by intravenous saline. Left ventricular chamber compliance was estimated as change in volume divided by change in pressure from minimum diastolic pressure to end-diastolic pressure (average LV chamber compliance).
Results:
Left ventricular pressure-volume loops were displayed on-line during the examination. When compared with the Simpson's method, DEQ underestimated end-diastolic volume (EDV) by 35% and overestimated end-systolic volume (ESV) by 14%. Beat-to-beat variability for ESV and EDV were 7.4% +/- 0.8% and 7.2% +/- 0.7 %, respectively. Volume loading increased LV end-diastolic pressure (LVEDP) from 14.0 +/- 1.6 to 24.7 +/- 2.0 mm Hg (P <.05) and EDV from 79 +/- 10 to 85 +/- 11 mL (NS), and decreased LV chamber compliance from 4.0 +/- 0.7 to 2.0 +/- 0.3 mL/mm Hg (P <.05).
Conclusion:
The current study demonstrates that LV pressure-volume loops can be displayed and evaluated in real-time during routine cardiac catheterization. This may represent a clinically useful method for identifying patients with reduced chamber compliance. The underestimation of the volumes by DEQ compared with the Simpson's method suggests that further refinements should be performed to improve the endocardial border detection algorithm.