| Objective To investigate the clinical value of 99mTc-MIBI gated myocardial perfusion imaging (G-MPI) before and after coronary artery bypass grafting in patients with coronary heart disease.Methods 22 patients (15 men and 7 women; mean age, 62.04 years±9.40), who prepared undergoing CABG, underwent both REST/Adenosine stress or REST/Nitroglycerin intervention G-MPI and coronary angiograph (CAG) 2 weeks before CABG. More than 2 radioactive defects in REST G-MPI shown in 12 patients, who underwent REST/NTG intervention G-MPI, were referred as group A. 10 patients with less than two radioactive defects in REST G-MPI, underwent REST/ADE stress G-MPI, were defined as group B. All patients underwent REST/ADE stress G-MPI within 6-12 months after successful CABG. Imaging analysis was finished by 2 experienced nuclear medicine physicians blinded. A semi-quantitative visual analysis employing a 20-segment and five-point scoring system was used to define the ADE score (SS), rest score (RS) and difference score (DS) before and after CABG; at the same time obtained left ventricular end-diastolic volume (EDV), end-systolic volume (ESV), and ejection fraction (LVEF); and estimate the value of G-MPI in judging therapeutic effectiveness of CABG and its prognosis, etc.Results 1. 66 coronary arteries were analyzed,57 shown positive results and 9 shown negative results in CAG. Of the 57 positive coronary arteries, it showed abnormal blood perfusion area corresponded with 50 arteries in resting MPI. Of the 9 negative coronary arteries, only 1 artery corresponding area showed abnormal in resting MPI. G-MPI has good consistency with CAG in diagnosis of CHD (Kappa=0.60,P<0.01). 2. 167 segments were shown abnormal blood perfusion in resting G-MPI before CABG, 87 segments were improved after CABG, and the total improvement rate was 52.09% (87/167). The improvement rate of radioactive decrease areas and defects were 55.71% (78/140) and 33.33% (78/140) respectively, there was significant difference between them two (χ2=4.543,P<0.05). In resting G-MPI, the number of average radioactive decreased areas and defects were 7.27±2.62 and 1.36±2.56 before CABG, and 5.63±3.47 and 1.13±2.82 after CABG respectively. The difference of average radioactive reductions was significant before and after CABG (t=2.705 , P < 0.05).The difference of average radioactive defects was insignificant(t=0.470,P>0.05). 3. In group B, there was significant difference in the improvement rate between RD and FD (χ2=5.108,P<0.05). 4. Among the 24 infarction segments of resting G-MPI, 7 segments improved in NTG intervention G-MPI; and after CABG, 8 segments finally improved, and the consistent rate is 87.5%. Of 81 ischemic segments, 29 segments improved in NTG intervention G-MPI; and after CABG, 43 segments finally improved, and the consistent rate is 67.44%. The difference of the improvement rate between NTG intervention G-MPI and REST G-MPI after CABG was significant(χ2=4.9,P=0.027<0.05). 5. The cardiac function parameters were improved after CABG. LVEF, ESV, and EDV before and after CABG were (45.82±15.69)%, (119.27±76.23)ml, (73.86±68.88)ml and (52.23±18.48)%, (93.14±63.06)ml, (53.41±50.97)ml separately. There was significant differences in those 3 parameters (P<0.05).Conclusions 1. CABG is an effective way in the therapy of CHD. 2. G-MPI has good consistency with CAG in diagnosing CHD. G-MPI can reveal the myocardial ischemic or infarction area, size, cardiac function parameters before CABG, and estimate the therapeutic effectiveness of CABG, also the determination of candidates for CABG. 3. The REST/NTG intervention G-MPI provides clinical value in identifying and predicting myocardial viability before Coronary revascularization. 4. By comparing the results of G-MPI pre and post CABG, we can better evaluate the effectiveness of CABG. |
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