Adenosine Stress Echocardiography

Exogenous adenosine has an even more pronounced negative chronotropic and dromotropic effect than endogenous adenosine, making the appearance of advanced atrioventricular blocks more frequent with adenosine than with dipyridamole for equivalent doses. Adenosine is a direct alternative to dipyridamole – the prototype of vasodilator adenosinergic stress. Like dipyridamole, antianginal drugs lower the sensitivity of adenosine stress echocardiography, whereas concomitant therapy with oral dipyridamole potentiates the cardiovascular effects of adenosine. The safety record and short half-life make adenosine especially indicated in patients with severe aortic stenosis or elderly patients, who may be especially vulnerable to complications during dipyridamole or dobutamine stress. In some countries an additional limitation of adenosine is its exorbitant cost: in the United States, adenosine costs $179, dipyridamole $95, and dobutamine $1 per examination. However in Europe, it is also possible to obtain a galenic formulation of adenosine from hospital pharmacies at a very low cost of around €1. Possibly, more expensive third-generation selective A2A agonists may find a selective indication in patients with moderate and severe chronic obstructive pulmonary disease, who have an indication for stress imaging and may want to avoid adenosine-induced bronchoconstriction and respiratory compromise – although in these patients the use of the bronchodilator dobutamine might be more reasonable.