Abstract 694: Ultrasound Biomicroscopy Assessed Radial Artery Intima-Media Thickness is Predictive of One-Year Cardiovascular Outcome in Patients With Suspected Coronary Artery Disease
Introduction: Radial artery intima-media thickness (rIMT) has been shown to correlate to the extent of coronary artery disease based on previous autopsy data. Flow-mediated vasodilatation assessed in this vascular bed is a widely used surrogate marker for cardiovascular status. By using ultrasound biomicroscopy (UBM) with transducer frequency up to 55 MHz with a spatial resolution of 20 μm, rIMT can be accurately measured.
Hypothesis: In the present study, we hypothesized that rIMT is predictive of one-year major adverse cardiovascular events (MACE) in patients with suspected coronary artery disease and that progression of rIMT can be followed.
Methods: 416 patients (mean age 62±9 years) with suspected coronary artery disease were recruited. 2D images of rIMT and carotid artery intima-media thickness (cIMT) were acquired bilaterally using 55 Mhz UBM, and an 8 MHz linear transducer, respectively. Both rIMT and cIMT were measured offline using a semi-automatic software and average intima-media thickness values of left and right side were used. All patients were followed up after one year with regard to MACE. rIMT was rescanned in a subset of 11 patients after one year.
Results: rIMT correlates to cIMT (r=0.33, p<0.0001) and is associated with serum levels of ApoA1 (r=−0.15, p<0.01) and HDL (r=−0.23, p<0.00001). During a median follow-up of 12.4 months, 58 MACE occurred including death, myocardial infarction, stroke and arterial revascularization. MACE versus no MACE patients showed significantly greater rIMT (348±73 μm vs 318±68 μm, p<0.01). In Kaplan-Meier survival analysis, patients with rIMT below the median value, had greater one-year event-free survival rate (p<0.01, OR=2.2). In a multivariate model of analysis including ApoA1, HDL and cIMT; rIMT was the only independent predictor of one-year MACE (p<0.05). rIMT progressed significantly (p<0.05) during one year with an average progression rate of 20 μm/year.
Conclusions: UBM-assessed rIMT is superior to cIMT in prediction of short-term MACE in patients with suspected coronary artery disease, and may serve as a novel surrogate vascular marker for cardiovascular diseases. UBM appears also to be useful to follow rIMT structure changes on individual basis.