CMR assessment of AMI patients treated by PCI shows delays in myocardial reperfusion despite initial achievement of TIMI 3 flow.
OBJECTIVE
Cardiovascular magnetic resonance imaging (CMR) perfusion studies performed early after successful angioplasty in AMI nearly always shows incomplete tissue reperfusion despite normal coronary blood flow by TIMI score. In contrast, when performed a few weeks or months after AMI, CMR first-pass perfusion (FP) is usually normal. This study was conducted to determine the kinetics of tissue reperfusion after reperfused AMI in humans.


RESULTS
We prospectively analyzed patients who presented with ST-segment elevation myocardial infarction between July 2002 and January 2005. Included patients had TIMI 3 flow after acute PCI and CMR FP imaging within four months post-MI. CMR FP was performed after injection of 20 cc of gadolinium chelate and imaging was performed with a Siemens Symphony 1.5 T. For FP analysis, each slice was divided into 8 segments which were subdivided into subepicardial and subendocardial layers. Normal perfusion was defined as less than 5% of segments involved by hypoperfusion. Patients were divided into groups according to the delay between MI/reperfusion and CMR. The reperfusion curve was established by plotting the percentage of patients with normal perfusion in each subgroup. A total of 184 CMR were analysed out of 146 patients included in the study. Probability of normal perfusion was 24%, 31%, 35%, 33% and 43% at respectively day 1, day 2, day 4, day 6 and day 8. This probability increased to 67% at week 2, and at week 3 reached a 100% probability (Spearman's rho -0.471, p = 0.001).


CONCLUSIONS
Despite complete restoration of epicardial flow, early myocardial reperfusion as assessed by CMR is very uncommon. Myocardial perfusion is progressively restored and capillary blood volume recovered normal values between weeks 2 and 4 after MI.
Noël
Bernard
B
Institut Cardiovasculaire Paris-Sud, Massy (France).
Morice
Marie-Claude
MC
Garot
Jérôme
J
Louvard
Yves
Y
Tavolaro
Oscar
O
Dumas
Pierre
P
Lévy
Maurice
M
Garot
Philippe
P
Lefèvre
Thierry
T