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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 ^sup 99m^Tc-sestamibi 1-d imaging protocol. A quick and simple RV-toleft 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.
Key Words: right ventricle; myocardial perfusion; SPECT; sestamibi
J Nucl Med 1999; 40:889-894
Increased right ventricular (RV) tracer uptake (Fig. 1) is not an uncommon finding in individuals with suspected or known coronary artery disease (CAD) studied with myocardial perfusion imaging. There are, however, few data in the literature regarding the meaning and significance of this finding in CAD patients. Increased RV tracer uptake is often seen in patients with chronic lung disease (1-5), congenital heart disease (5-il), valvular heart disease (6-8,12,13) and primary pulmonary hypertension (1,5,7,8), and positive correlations to RV end-systolic pressure (RV-ESP) and pulmonary artery pressure (PAP) have been demonstrated (2,4,6-10,12).
Increased RV tracer uptake in myocardial perfusion studies generally has been seen as a sign of RV hypertrophy. If this is valid in patients with CAD without pulmonary or valvular heart disease, then information about backward failure...