Adenosine stress protocols for nuclear cardiology imaging.

Area of Science:

• Cardiology
• Nuclear Medicine
• Diagnostic Imaging

Background:

• Myocardial perfusion imaging (MPI) with treadmill stress testing is standard for coronary artery disease (CAD) assessment.
• Pharmacologic stress testing is a viable alternative for patients unable to perform treadmill tests, comprising 40% of nuclear stress tests.
• Adenosine stress protocols are increasingly used for pharmacologic stress MPI.

Purpose of the Study:

• To introduce and evaluate adenosine stress protocols in a nuclear laboratory setting.
• To compare the frequency and severity of side-effects between two adenosine stress protocols: AdenoSCAN and AdenoEX.
• To determine optimal imaging times for each protocol.

Main Methods:

• Two adenosine stress protocols were performed on 186 patients undergoing MPI with 99mTc-sestamibi.
• The AdenoSCAN protocol involved intravenous adenosine (140 µg/kg/min for 3 min) in 47 patients.
• The AdenoEX protocol combined adenosine with low-level bicycle exercise (50W) in 139 patients.

Main Results:

• The AdenoEX protocol was well-tolerated by all patients, with reduced side-effects and improved image quality compared to AdenoSCAN.
• AdenoEX demonstrated a significantly better heart-to-liver ratio.
• Optimal imaging time for AdenoEX was established at 15 minutes post-stress, versus a minimum of 45 minutes for AdenoSCAN.

Conclusions:

• The AdenoEX protocol offers advantages over AdenoSCAN, including fewer side-effects and enhanced patient tolerance.
• AdenoEX improves image quality and increases laboratory efficiency through earlier imaging.
• AdenoEX is a preferred adenosine stress protocol for MPI in CAD assessment.