PET perfusion and vasodilator function after angioplasty for acute myocardial infarction.
The aims of this study were to validate invasive coronary Doppler flows against noninvasive PET assessments of myocardial perfusion and to examine the timing and degree of regional coronary vasodilator reserve recovery in patients who are successfully reperfused with primary angioplasty (PTCA) for acute myocardial infarction.


METHODS
PTCA was performed in 21 consecutive patients with acute myocardial infarction; the final diameter stenosis was 25% +/- 7%. After restoration of TIMI Grade 3 flow, all patients underwent quantitative coronary angiography and distal Doppler coronary blood flow studies (basal and after adenosine-induced hyperemia) in the infarct and noninfarct vessels. Regional myocardial perfusion and vasodilator function were quantitated after intravenous adenosine infusion PET in all patients at 26 +/- 9 hr after acute PTCA. These were repeated in 17 patients 9 +/- 3 days later.


RESULTS
Post-PTCA resting coronary flow was 35 +/- 15 ml/min in the infarct-related vessels and 50 +/- 24 ml/min during peak hyperemia (p < 0.05). Coronary flow reserve (CFR) was 1.48 +/- 0.34 and 2.08 +/- 0.62 in the infarct and noninfarct vessels, respectively (p < 0.001). Early (< 36 hr) PET myocardial perfusion reserves (MPR) in the infarct and noninfarct regions were 1.59 +/- 0.33 and 2.03 +/- 0.62 (p < 0.01). Doppler CFR and PET MPR were correlated in the infarct (r = 0.61, p < 0.01) and noninfarct (r = 0.77, p < 0.0001) regions. Follow-up PET studies demonstrated improved MPR in both infarct and noninfarct regions (1.93 +/- 0.52 versus 2.54 +/- 0.97, p < 0.01). The improvement in coronary vasodilator function from the time of acute PTCA to follow-up PET in the infarct region was significant (p = 0.005).


CONCLUSIONS
After successful mechanical revascularization by PTCA after acute myocardial infarction, intracoronary Doppler blood flows and noninvasive PET regional myocardial perfusion are correlated within the wide range of reperfusion blood flows observed in patients with contrast angiographic TIMI Grade 3 flow. Serial PET studies demonstrated a trend towards continued improvement in the vasodilator response in infarct-related myocardial regions after the restoration of blood flow by PTCA. PET offers the potential for accurate noninvasive serial assessment of reperfusion blood flow after primary angioplasty for acute myocardial infarction.
Stewart
R E
RE
Division of Cardiology and Nuclear Medicine, William Beaumont Hospital, Royal Oak, Michigan, USA.
Miller
D D
DD
Bowers
T R
TR
McCullough
P A
PA
Ponto
R A
RA
Grines
C L
CL
O'Neill
W W
WW
Juni
J E
JE
Safian
R D
RD
D015906:Angioplasty, Balloon, Coronary; D001783:Blood Flow Velocity / Q000502:physiology; D017023:Coronary Angiography; D003326:Coronary Circulation / Q000502:physiology; D003331:Coronary Vessels / Q000000981:diagnostic imaging / Q000503:physiopathology; D015150:Echocardiography, Doppler; D005260:Female; D005500:Follow-Up Studies; D006321:Heart / Q000000981:diagnostic imaging*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D014055:Tomography, Emission-Computed; D018084:Ultrasonography, Interventional; D014664:Vasodilation / Q000502:physiology