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Significance of increased right ventricular uptake on 99mTc-sestamibi SPECT in patients with coronary artery disease
F Mannting1, Y V Zabrodina, C Dass
1Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02155, USA.
Insights
Increased right ventricular (RV) tracer uptake in coronary artery disease (CAD) patients indicates RV pressure overload. This finding, identified through myocardial perfusion imaging, suggests backward failure with negative prognostic implications.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- The clinical significance of elevated right ventricular (RV) tracer uptake in coronary artery disease (CAD) patients without pulmonary or valvular issues is not well understood.
- Right heart catheterization is the standard for assessing RV pressures.
Purpose of the Study:
- To determine if increased RV tracer uptake on SPECT myocardial perfusion imaging correlates with elevated RV pressures in CAD patients.
- To establish RV tracer uptake as a potential non-invasive marker for RV pressure overload.
Main Methods:
- Prospective study of 40 CAD patients with increased RV uptake and 35 controls, all undergoing SPECT myocardial perfusion imaging and right heart catheterization.
- Calculated RV to left ventricular (LV) myocardial uptake ratio from SPECT data.
- Measured RV end-systolic pressure (RV-ESP) and mean pulmonary artery pressure (PAP) via catheterization.
Main Results:
- CAD patients with increased RV uptake showed significantly higher RV-ESP (90%) and PAP (97.5%) compared to controls.
- A strong positive correlation was observed between the RV/LV uptake ratio and both RV-ESP (r=0.45, P=0.003) and PAP (r=0.52, P<0.001).
Conclusions:
- Increased RV tracer uptake on standard myocardial perfusion studies can effectively identify RV pressure overload in CAD patients.
- In the absence of other cardiac or pulmonary disease, this finding signifies backward failure, a critical negative prognostic indicator.
Unlabelled:
The significance of increased right ventricular (RV) tracer uptake in patients with coronary artery disease (CAD) without pulmonary or valvular heart disease is unclear.
Methods:
Forty consecutive patients with increased RV uptake on SPECT myocardial perfusion imaging and right heart catheterization within 4 wk were studied prospectively. Thirty-five individuals with very low likelihood of CAD served as controls. Rest and stress SPECT myocardial perfusion data were obtained using a standard 99mTc-sestamibi 1-d imaging protocol. A quick and simple RV-to-left ventricular (LV) myocardial uptake ratio was calculated from the maximum counts per pixel detected in the right and left ventricles using the reconstructed coronal slices. RV end-systolic pressure (RV-ESP), mean pulmonary artery pressure (PAP) and pulmonary capillary wedge pressure were obtained by standard techniques.
Results:
The RV/LV uptake ratio in the controls was 0.31+/-0.05. Thirty-six of the 40 (90%) CAD patients with increased RV tracer uptake had increased RV-ESP, and 39 (97.5%) had increased PAP. Highly significant positive correlations between the RV/LV uptake ratio and RV-ESP and PAP were found (r = 0.45, P = 0.003; and r = 0.52, P < 0.001, respectively).
Conclusion:
Increased RV uptake, assessed from standard myocardial perfusion studies, can identify RV pressure overload among patients with CAD. In the absence of pulmonary or valvular heart disease, increased RV uptake (i.e., RV pressure overload) indicates significant backward failure, a variable with known significant negative prognostic implications.