Usefulness of pulse-wave Doppler tissue sampling and dobutamine stress echocardiography for the diagnosis of right coronary artery narrowing

To study the feasibility and diagnostic accuracy of right coronary artery (RCA) narrowing by right ventricular (RV) pulse-wave Doppler tissue sampling during dobutamine stress echocardiography (DSE), 30 patients (mean age 55 ± 9.5 years, 26 men) with suspected coronary artery disease underwent DSE (up to 40 μg/kg/min with additional atropine during submaximum heart rate responses). Pulse-wave Doppler tissue sampling of RV free walls close to the tricuspid annulus was performed in the apical 4-chamber view. The maximum velocity during the ejection phase, early, and late diastole was measured. Data from 5 consecutive beats were averaged. The measurements were repeated at rest, at low dose (10 μg/kg/min), and at peak dobutamine stress. The results were evaluated for the prediction of significant proximal or medium RCA narrowing (≤50% diameter stenosis, assessed by quantitative coronary angiography within the previous 3 months). A progressive increase of the ejection phase velocity (>25% between 10 μg/kg/min and peak stress) was predictive of a normal RCA, whereas a blunted increase and/or decrease (<25% of increase) was predictive of significant RCA narrowing: sensitivity (95% confidence intervals): 82% (68 to 96), specificity: 78% (67 to 93), positive predictive value: 69% (52 to 86), negative predictive value: 88% (75 to 100), accuracy: 79% (65 to 94). Pulse-wave Doppler tissue sampling provided analyzable data in 100%, whereas the visual assessment of gray-scale images was possible only in 90%. Thus, in Patients with suspected RCA narrowing, pulse-wave Doppler tissue sampling during DSE was able to diagnose significant RCA narrowing.

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