Adenosine stress protocols for myocardial perfusion imaging

Abstract

Background/Aim. Treadmill test combined with myocardial perfusion scintigraphy (MPS) is a commonly used technique in the assessment of coronary artery disease. There are many patients, however, who may not be able to undergo treadmill test. Such patients would benefit from pharmacological stress procedures combined with MPS. The most commonly used pharmacological agents for cardiac stress are coronary vasodilatators (adenosine, dipyridamol) and catecholamines. Concomitant low-level treadmill exercise with adenosine pharmacologic stress (AdenoEX) during MPS has become commonly used in recent years. A number of studies have demonstrated a beneficial impact of AdenoEX protocol. The aim of the study was, besides introducing into practice the two types of protocols of pharmatological stress test with adenosine, as a preparation for MPS, to compare and monitor the frequency of their side effects to quality, acquisition, as well as to standardize the onset time of acquisition (diagnostic imaging) for both protocols. Methods. A total of 130 patients underwent pharmacological stress test with adenosine (vasodilatator). In 108 of the patients we performed concomitant exercise (AdenoEX) of low level (50W) by a bicycle ergometar. In 28 of the patients we performed Adenosine abbreviated protocol (AdenoSCAN). Side effects of adenosine were followed and compared between the two kinds of protocols AdenoEX and AdenoSCAN. Also compared were image quality and suggested time of acquisition after the stress test. Results. Numerous side effects were found, but being short-lived they did not require any active interventions. The benefit of AdenoEX versus AdenoSCAN included decreased side effects (62% vs 87%), improved safety and patients tolerance, improved target-to-background ratios because of less subdiaphragmatic activity, earlier acquisition, and improved sensitivity. Conclusion. The safety and efficacy of adenosine pharmacological stress is even better with concomitant exercise. In the light of these benefits we recommend AdenoEX whenever possible.