Cor Vasa 2007, 49(11):392-396 | DOI: 10.33678/cor.2007.140

Myocardial viability determined by positron emission tomography (PET) at 1-3 months after primary coronary intervention (PCI). A pilot study.

Petr Niederle¹, Otakar Bělohlávek², Pavel Formánek¹, Eva Mandysová¹

¹ Kardiologické oddělení

² Oddělení nukleární medicíny a PET-centrum, Nemocnice Na Homolce, Praha, Česká republika

Aim:
The objective of the pilot prospective study was to assess myocardial viability and perfusion in patients undergoing primary coronary intervention (PCI) for acute ST-segment elevation myocardial infarction (STEMI = 22 patients) and non-ST-segment elevation myocardial infarction (NSTEMI = 5 patients), with a positive enzymatic response (troponin I) in all.

Patients and methods:
Twenty seven patients (22 men and 5 women; mean age 55.8 ± 5.5 yrs) were enrolled into the study. The PCI involved angioplasty (PTCA) with stenting (n = 17), primary stenting (n = 7), and single PTCA (n = 3). The presence of a viable myocardium was verified by positron emission tomography (PET), if radioactivity of 18F-fluorodeoxyglucose (FDG) administered i.v. into the infarct zone was ≥ 50 % of that in the intact myocardium. The first examination was performed during hospitalization immediately after PTCA and was repeated at 2.0 ± 0.5 months. Echocardiography evaluating left ventricular diameters and ejection fraction was also performed in the course of hospital stay and repeated at the time of follow-up PET.

Results:
Sixteen of the 27 subjects (59%) had a viable myocardium within the infarct area, while FDG-PET results in 11 patients did not meet the pre-defined criteria. Myocardial perfusion assessed by single photon emission computed tomography (SPECT) was consistent with PET findings (PET/SPECT match) in 21 subjects, while significant hypoperfusion/ defect was present in the remaining six patients (PET/SPECT mismatch). When analyzing the potential impact of the time delay from the onset of chest pain to coronary intervention, a viable myocardium was documented in most patients undergoing intervention within 24 hours. There were no significant differences between the groups of patients with viable vs. non-viable myocardium in sex, culprit-lesion artery, values of an inflammation marker (CRP) and total cholesterol. At follow-up echocardiography 1-3 months later, the viable myocardium showed a tendency toward positive left ventricular remodeling.

Conclusion:
Our relatively small pilot study designed to detect viable myocardium using PET has not confirmed an anticipated benefit of acute coronary intervention performed only within 12 hours of the onset of chest pain as compared with a later intervention (within 24 h). Therefore, the open infarct artery concept remains partially valid also for not exactly defined coronary interventions undertaken within 24 hours. An objectively confirmed viable myocardium tends to restore its function within a two-month period.

Keywords: Myocardial viability; Time factor; Positron emission tomography

Published: November 1, 2007  Show citation