Patient-tailored risk assessment of obstructive coronary artery disease using Rubidium-82 PET-based myocardial flow...

Area of Science:

• Cardiology
• Nuclear Medicine
• Radiology

Background:

• Obstructive coronary artery disease (oCAD) diagnosis often relies on invasive procedures.
• Non-invasive assessment using Rubidium-82 (Rb-82) Positron Emission Tomography (PET) offers an alternative.
• Myocardial flow reserve (MFR) is a key metric derived from Rb-82 PET, reflecting coronary microvascular function.

Purpose of the Study:

• To estimate the probability of obstructive coronary artery disease (oCAD) in individual patients.
• To assess the role of myocardial flow reserve (MFR) measured by Rb-82 PET in conjunction with visual scan interpretation.
• To determine how MFR influences oCAD probability across different visual scan classifications (normal, small defect, large defect).

Main Methods:

• A cohort of 1519 consecutive patients without prior CAD history undergoing Rb-82 PET/CT was analyzed.
• PET images were visually assessed and categorized as normal, small defect (5-10%), or large defect (>10%).
• The probability of oCAD was calculated as a function of MFR for each category, with invasive coronary angiography serving as the primary endpoint.

Main Results:

• In patients with visually normal scans, oCAD probability increased from 1% to 10% as MFR decreased from 2.1 to 1.3.
• For scans with small defects, oCAD probability rose from 13% to 40% with decreasing MFR (2.1 to 0.7).
• Scans with large defects showed a steeper increase in oCAD probability, from 45% to over 70% as MFR decreased from 2.1 to 0.7.

Conclusions:

• Visual PET interpretation alone can distinguish patients with >10% oCAD risk.
• However, MFR significantly impacts individual oCAD risk assessment.
• Combining visual interpretation with MFR provides a more accurate individual risk stratification, potentially guiding treatment decisions.