Interv Akut Kardiol. 2024;23(1):33-36 | DOI: 10.36290/kar.2024.001

Pharmacological stress test using regadenoson in conventional and dynamic cardiac SPECT

Milan Kamínek^{1, 2}, Vladimír Kincl², Martin Havel^{1, 3}

¹ Klinika nukleární medicíny, LF UP a Fakultní nemocnice Olomouc

² Mezinárodní centrum klinického výzkumu, Fakultní nemocnice u sv. Anny, Masarykova univerzita, Lékařská fakulta, Brno

³ Klinika nukleární medicíny, LF Ostravské univerzity a Fakultní nemocnice Ostrava

Regadenoson as a selective A_2A adenosine enables pharmacological stress when exercise stress techniques would be impossible or very difficult. We present two case reports demonstrating its advantages. In case 1, we initially attempted to induce stress using physical exercise in a 77-year-old male patient after coronary artery bypass graft. Due to inadequate heart rate increase, the stress was promptly converted to pharmacological stress using regadenoson in combination with a low level of exercise. Single-photon emission computed tomography (SPECT) showed extensive ischaemia of the lateral wall. Coronary angiography subsequently revealed vein graft occlusion at the left circumflex artery. Case 2 demonstrates recent advances in SPECT technology. Modern multidetector Cadmium Zinc Telluride (CZT) cameras enable dynamic acquisition and quantification of coronary flow reserve (CFR). It can be helpful in identifying multivessel disease or microvascular ischaemia. CFR is calculated as the ratio between myocardial blood flow during stress vasodilator hyperaemia and flow at rest. In a 50-year-old diabetic patient, a conventional cardiac SPECT showed normal post-stress left ventricular perfusion and function. Dynamic SPECT showed normal myocardial blood flow (MBF) and normal CFR ≥ 2. During 18 months of follow-up, no cardiac event was observed in this patient.

Keywords: regadenoson, cardiac SPECT, dynamic SPECT, MBF, CFR.

Received: October 13, 2023; Revised: February 9, 2024; Accepted: February 14, 2024; Published: April 29, 2024  Show citation