Noninvasive determination of coronary blood flow velocity with cardiovascular magnetic resonance in patients after stent deployment.
BACKGROUND
In patients with coronary artery stents, no direct noninvasive coronary artery imaging is possible with magnetic resonance (MR). A well-established method for the assessment of the functional significance of a coronary lesion is the measurement of coronary flow reserve by invasive intracoronary Doppler. The purpose of the study was to determine coronary flow velocity reserve (CFVR) with MR after stent deployment.


RESULTS
Thirty-eight patients after successful PTCA and stent deployment were included. CFVR was measured perpendicular to the artery distal to the stent using phase-contrast velocity quantification at rest and during adenosine-stimulated hyperemia with a 1.5T MR tomograph (ACS NT, Philips). Measurements were repeated after 3 months and compared with invasive coronary angiography. In 18 patients, additional invasive Doppler flow measurements were obtained. CFVR could be determined in 29 of 38 (76%) of the patients. After 3 months, significant differences were obtained between coronary arteries with and without restenosis. Using a threshold of 1.2, a sensitivity of 83% with a specificity of 94% was achieved for > or =75% stenoses. CFVR with CMR was similar to Doppler results (r=0.87), with a mean relative difference of 7.5%.


CONCLUSIONS
In patients with preserved coronary microcirculating vasoreactivity that are suitable for MR coronary angiography and flow assessments, CMR measures of coronary blood flow velocities reserve may be used to detect in-stent restenosis.
Nagel
Eike
E
Internal Medicine/Cardiology, German Heart Institute, Augustenburger Platz 1, D-13353 Berlin, Germany. eike.nagel@dhzb.de
Thouet
Thomas
T
Klein
Christoph
C
Schalla
Simon
S
Bornstedt
Axel
A
Schnackenburg
Bernhard
B
Hug
Jürgen
J
Wellnhofer
Ernst
E
Fleck
Eckart
E
D001783:Blood Flow Velocity; D003326:Coronary Circulation; D023903:Coronary Restenosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000209:etiology; D015150:Echocardiography, Doppler; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D015607:Stents / Q000009:adverse effects*