Cor Vasa 2002, 43(4):176-180
Is positron emission tomography beneficial in myocardial viability evaluation?
- 1 Kardiologické oddělení
- 2 Oddělení nukleární medicíny - PET centrum, Nemocnice Na Homolce, Praha, Česká republika
Aim:
To investigate the clinical benefit of positron emission tomography (PET) used to estimate myocyte metabolic activity in combination with single-photon emission computed tomography (SPECT) for myocardial perfusion studies in left ventricular (LV) myocardial viability assessment.
Patients and methods:
From February 2000 through October 2001, a cohort of 58 patients (46 males, 12 females; mean age 62 ± 10.2 yrs) with ischemic heart disease (IHD), as documented by coronary angiography, underwent SPECT and PET studies for myocardial viability estimation. 18F-fluorodeoxyglucose PET was used for myocardial glucose uptake assessment and 99mTc-MIBI SPECT for myocardial perfusion studies. Match in myocardial metabolic and perfusion defects identified a non-viable myocardium, while a viable myocardium presented perfusion defects with preserved, or only decreased metabolic activity in the same region (uptake > 50% of the normal myocardium).
Results:
32 patients (group A) with a SPECT/PET match exhibited a non-viable scared myocardium (17 post-myocardial infarction [MI] scars, 5 severe LV dysfunction due to IHD; 4 after direct and 2 after rescue coronary angioplasty, another 2 suffered from an arrhythmic form of IHD, and the remaining 2 exhibited residual hibernated myocardium in the periphery of existing defects-1 unstable angina and 1 after thrombolytic treatment of MI). Even in the presence of a non-viable myocardium, 5 subjects underwent coronary angioplasty and another one revascularization surgery on his own wish. One post-MI patient with a SPECT/PET match was referred to surgery only after electrophysiological LV mapping with a CARTO system, but his global LV function did not improve until half way through his follow-up. The other 26 patients formed a group with SPECT/PET mismatch (group B), i.e., one shown to have a viable myocardium. Twenty-four of these patients were referred to a reperfusion procedure. The frequency of indications for coronary intervention differed significantly between the two groups (A: 6 out of 32 [19 %/] vs. B: 24 out of 26 [92 %]; p < 0.001). In fact, two group B patients (both after previous aorto-coronary bypass surgery) refused surgical re-intervention as recommended; and the surgeon refused another two for technically unfeasible coronary reconstruction. To date, coronary surgery/intervention has been performed in 19 patients, with one still on the surgical waiting list.
Conclusion:
We believe that perfusion/metabolic mismatch (SPECT/PET) imaging obviously facilitates the clinician's decision-making process in correct detection of a viable myocardium. There is no doubt such patients are to be referred to a coronary reconstructive intervention. However, the fact is that other factors (clinical, technical, personal) play a substantial role in the outcome of those patients.
Keywords: Ischemic heart disease; Myocardial viability; Positron emission tomography
Published: April 1, 2002 Show citation