ISSN 2996-8215
International Journal of Cardiology | Vol. 12, No. 12, December 2021 | pp. 89–96
DOI: 10.46882/2021/IJC/000153
Original Research Article
Association Between Coronary Artery Calcium Volume Scores and Quantitative Myocardial Perfusion Reserve via Rubidium-82 PET Imaging
Arjun Patel¹, Rohan Mehta¹, Vikram Singh²
¹Department of Cardiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India
²Division of Cardiovascular Radiology, All India Institute of Medical Sciences, New Delhi, India
Abstract:
The Agatston coronary artery calcium (CAC) score is a validated tool for predicting cardiovascular events, but its linear correlation with functional myocardial ischemia remains variable. This study investigated the quantitative relationship between CAC volume scores derived from computed tomography and stress myocardial blood flow (MBF) along with myocardial perfusion reserve (MPR) quantified non-invasively via Rubidium-82 (82Rb) positron emission tomography (PET). We prospectively evaluated 140 symptomatic patients with suspected coronary artery disease who underwent both non-contrast CT for calcium calculation and stress/rest 82Rb PET imaging within 14 days. Diffuse microvascular ischemia was defined as a global MPR less than 2.0 in the absence of regional focal defects. Severe macrovascular calcification (CAC volume score greater than 400) was present in 52 patients (37.1%). Global stress MBF was significantly lower in the high-CAC cohort compared to the low-CAC group (1.64 ± 0.32 mL/min/g vs. 2.24 ± 0.44 mL/min/g, p < 0.001). Consequently, baseline high CAC volume scores strongly correlated with impaired global MPR (r = -0.68, p < 0.001). Multivariable linear regression confirmed that log-transformed CAC volume scores were independently associated with reduced global MPR (beta-coefficient = -0.34, p = 0.002), after adjusting for traditional metabolic risk indices and stenotic severity. Extensive coronary artery calcification volumes demonstrate a strong independent association with impaired quantitative myocardial perfusion reserves, indicating a severe burden of concurrent coronary microvascular dysfunction.
Keywords: Coronary artery calcium, Positron emission tomography, Myocardial perfusion reserve, Computational imaging, Microvascular dysfunction, Ischemia
Received: September 05, 2021; Revised: October 20, 2021; Accepted: November 12, 2021; Published: December 18, 2021