Introduction:
In patients with acute myocardial infarction (AMI), coronary vasomotor function is not only impaired in the myocardial territory supplied by the culprit-artery but also in remote myocardium supplied by angiographically normal vessels.
Aims:
The aim was to investigate the temporal evolution of coronary vasodilatory reserve in patients with AMI by use of [15O]H2O PET, after successful percutaneous coronary intervention (PCI).
Methods:
Fourty-four patients with AMI and successful revascularization by PCI were included (i.e. TIMI II or III flow after coronary stenting). Subjects were examined one week and three months after AMI with [15O]H2O PET to assess the coronary flow reserve (CFR). CFR was defined as the ratio of myocardial blood flow during hyperemia (hMBF) and rest (MBF). Additionally, 45 age and sex matched subjects without a prior cardiac history underwent similar scanning procedures and served as a control group.
Results:
At baseline, CFR averaged 1.77 ± 0.63 in infarcted myocardium versus 2.41 ± 0.79 in remote myocardium (p < 0.001). In comparison, CFR in the control group averaged 4.16 ± 1.45 (p = 0.001 versus both). During follow-up, the CFR increased from 1.77 ± 0.63 to 2.75 ± 0.89 in infarcted myocardium (p < 0.001), and from 2.41 ± 0.79 to 2.85 ± 0.75 in remote myocardium (p = 0.001). This was predominantly due to an increase in hMBF, from 1.64 ± 0.54 to 2.19 ± 0.74 mL/min/g in infarcted myocardium (p < 0.001), and 2.20 ± 0.56 to 2.61 ± 0.65 mL/min/g in remote myocardium (p = 0.001).
Conclusions:
Coronary vasodilatory reserve is impaired in both ischemic and remote myocardium directly after AMI. Following successful revascularization, the coronary vasodilatory reserve significantly improved in both regions. As a consequence, these early and late post-infarct alterations in remote myocardium may also affect temporal infarct evolution and recovery of left ventricular function.
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