123I-MIBG imaging can be used to evaluate microvascular disturbance caused by embolization by microdebris after rotational atherectomy.
BACKGROUND
During rotational atherectomy (RA), the coronary atherosclerotic plaque is largely pulverized into microdebris, which may cause serious hemodynamic instability owing to significant segmental left ventricular asynergy embolization of the distal microvasculature by atheromatous debris and associated vasospasm.


OBJECTIVE
To evaluate the usefulness of 123I-metaiodobenzylguanidine (123I-MIBG) in the examination of microvascular embolization after RA.


RESULTS
Nineteen patients with stable effort angina pectoris who had undergone RA were evaluated in this study. Left ventricular ejection fraction (LVEF) was determined by left ventriculography immediately before and after RA. The serum concentration of creatine phosphokinase (CPK), creatine phosphokinase-myocardial band (CPK-MB) isozyme, and cardiac troponin-T was determined after RA. 99mTc-methoxyiso-butylisonitrile (99mTc-MIBI) and 123I-MIBG scintigraphic examinations were also performed 1 day after RA. The regional defect score (RDS) was determined from 99mTc-MIBI scintigraphic findings, while early and delayed RDS, heart-to-mediastinum count ratios (H/M ratios), and washout rate (WR) were determined from 123I-MIBG scintigraphy. After RA, the left ventriculographic LVEF mildly decreased by <10% in ten patients (group A), but it decreased by >10% in the remaining nine patients (group B). There were no differences in baseline clinical characteristics between the two groups. The CPK, CPK-MB isozyme, troponin-T, RDS by 99mTc-MIBI, H/M ratios, and WR after RA were similar in the two groups. However, the RDSs determined from early and delayed 123I-MIBG in group A were significantly lower than those in group B (4.5 +/- 3.8 vs. 13.4 +/- 10.8, P < 0.05; 9.0 +/- 6.3 vs. 17.7 +/- 10.0, P < 0.05, respectively). Moreover, there were significant correlations between delta LVEF and troponin-T (r = 0.54, P < 0.05) and RDSs of early and delayed 123I-MIBG (r = 0.46, P < 0.05; r = 0.64, P < 0.05, respectively).


CONCLUSIONS
These findings suggest that 123I-MIBG imaging can be used to evaluate microvascular disturbance caused by embolization by microdebris after RA.
Hatori
Takashi
T
Department of Medicine and Biological Science, Graduate School of Medical Sciences, Gunma University, 3-39-15, Showa-machi, Maebashi, Gunma 371-0034, Japan. hatorit@med.gunma-u.ac.jp
Toyama
Takuji
T
Kasama
Shu
S
Suguta
Masahiko
M
Nakano
Akihiko
A
Hasegawa
Akira
A
Endo
Keigo
K
Kurabayashi
Masahiko
M
D019797:3-Iodobenzylguanidine; D000368:Aged; D017225:Atherectomy, Coronary / Q000009:adverse effects*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging* / Q000209:etiology*; D004617:Embolism / Q000000981:diagnostic imaging* / Q000209:etiology*; D005260:Female; D006801:Humans; D008297:Male; D008833:Microcirculation / Q000473:pathology*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine