Adenosine induces coronary vasodilation and simultaneously reduces splanchnic perfusion. In adenosine stress perfusion during cardiovascular magnetic resonance delay of splenic enhancement is an indicator of adequate adenosine effect. It is unclear whether this effect can be assessed by color Doppler of the splenic artery.

In 26 patients splenic artery color Doppler was performed during an infusion of adenosine, peak velocity in the splenic artery was measured prior to the infusion and at 2 minutes. Results were compared qualitatively to perfusion imaging in magnetic resonance.

24 patients showed a drop of splenic artery peak velocity from 62.3±18.1 to 40.4±15.7cm/s (p<0.001), which correlated with perfusion restriction in magnetic resonance. 2 Patients with constant splenic artery flow did not show perfusion restriction.

This new application is feasible and might be applied to rule out inadequate adenosine effect during measurement of fractional flow reserve in coronary catheterization. 

Figure 1        Example of positive systemic adenosine response

A: Normal color Doppler signal of the spleen (S) at rest (left), suppressed flow signal under adenosine (right). B: Drop of baseline peak velocity in the splenic artery (44.6 cm/s, left) under adenosine (30.0 cm/s, right) visualized by pulsed wave Doppler. C: Magnetic resonance stress perfusion under adenosine. Maximum enhancement of the myocardium (M) is visible in the second image while enhancement of the spleen (s) is delayed.

Figure 2        Example of negative systemic adenosine response

A: Normal color Doppler signal of the spleen (S) at rest (left) and under adenosine (right). B: Pulsed wave Doppler of the splenic artery. No relevant change of peak velocity in the splenic artery under adenosine (right) compared to resting conditions (left). C: Magnetic resonance stress perfusion under adenosine. Equal enhancement pattern of the myocardium (M) and the spleen (S) under adenosine, no restriction of splenic perfusion visible.