Abstract 14962: Myocardial Blood Flow changes during Cold Pressor Testing for the assessment of endothelial function. A Cardiovascular Magnetic Resonance study.
Introduction: Cold Pressor Testing (CPT) is an endothelial dependent stressor that can assess the functional integrity of the endothelium and diagnose early coronary endothelial dysfunction, for example in smokers. To date the use of CPT is limited by invasive or ionizing methods of detection. We aimed to determine the feasibility of CPT perfusion Cardiovascular Magnetic Resonance (CMR), to detect changes in myocardial blood flow (MBF) during CPT and compare the effects to that of adenosine stress in healthy volunteers and smokers.
Method: Twenty one volunteers (11 healthy and 10 age-matched smokers) underwent rest, CPT and adenosine stress perfusion-CMR (1.5T) at 15 minute intervals during a single session. Smokers averaged 2.5 pack years. MBF was calculated for the endocardium, epicardium and transmurally using Fermi-constrained deconvolution.
Results: MBF increased significantly during CPT in both healthy (p=0.003) and smoking groups (p=0.009). Smokers had a lower resting MBF and smaller rise (21% vs 30%) at CPT but this difference was not significant (p=0.07). MBF in separate layers showed a significant (p<0.05) endo-epi gradient at rest and CPT which reversed during adenosine hyperemia, (Table 1). Linear regression analysis demonstrated mean arterial pressure (MAP) as a predictor of MBF at rest, CPT and adenosine stress. Male sex and Coronary vascular resistance were independent predictors of higher MBF during CPT in healthy individuals but not smokers (B 1.05, p=0.03 and B -0.02, p=0.04 respectively).
Conclusion: Perfusion-CMR CPT assessment detects a 20-30% increase in MBF from rest. There is a trend to a smaller increase of MBF in smokers compared to an age matched cohort, despite a short smoking history. The separate myocardial layers demonstrate an endo-epi gradient that is maintained during physiological (CPT) but not pharmacological (adenosine) stress. Perfusion-CMR CPT may thus be a useful non-invasive technique to identify endothelial dysfunction.
- © 2011 by American Heart Association, Inc.