Myocardial beta-adrenergic receptor density assessed by 11C-CGP12177 PET predicts improvement of cardiac function after carvedilol treatment in patients with idiopathic dilated cardiomyopathy.
We evaluated whether myocardial beta-adrenergic receptor (beta-AR) density, as determined by 11C-CGP12177 PET, could predict improvement of cardiac function by beta-blocker carvedilol treatment in patients with idiopathic dilated cardiomyopathy (IDC).


METHODS
Ten patients with IDC (left ventricular ejection fraction [LVEF]<45%) were studied. Myocardial beta-AR density was estimated using 11C-CGP12177 PET before treatment with carvedilol. Changes of LVEF in response to dobutamine infusion (DeltaLVEF-dobutamine) were also measured by echocardiography. Changes of LVEF (DeltaLVEF-carvedilol) were evaluated after 20 mo of carvedilol treatment.


RESULTS
Baseline myocardial beta-AR density significantly correlated with DeltaLVEF-carvedilol (r=-0.88, P<0.001). In contrast, DeltaLVEF-dobutamine did not correlate with DeltaLVEF-carvedilol (P=0.65). Myocardial beta-AR density was the significant multivariate independent predictor of DeltaLVEF-carvedilol (beta=-0.88, P<0.001) among univariate predictors, including functional class (r=0.76, P<0.05), plasma norepinephrine (r=0.85, P<0.01), LVEF (r=-0.64, P<0.05), and age as confounding factors. Furthermore, myocardial beta-AR density was significantly correlated with plasma norepinephrine (r=-0.79, P<0.01) and LVEF (r=0.70, P<0.05).


CONCLUSIONS
Myocardial beta-AR density is more tightly related to improvement of LVEF-carvedilol than is cardiac contractile reserve in patients with IDC. Patients with decreased myocardial beta-AR have higher resting adrenergic drive, as reflected by plasma norepinephrine, and may receive greater benefit from being treated by antiadrenergic drugs.
Naya
Masanao
M
Department of Cardiovascular Medicine, Hokkaido University Graduate School of Medicine, Sapporo, Japan. naya@med.hokudai.ac.jp
Tsukamoto
Takahiro
T
Morita
Koichi
K
Katoh
Chietsugu
C
Nishijima
Kenichi
K
Komatsu
Hiroshi
H
Yamada
Satoshi
S
Kuge
Yuji
Y
Tamaki
Nagara
N
Tsutsui
Hiroyuki
H
D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use*; D000368:Aged; D002227:Carbazoles / Q000627:therapeutic use*; D002250:Carbon Radioisotopes; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging* / Q000188:drug therapy* / Q000503:physiopathology; D000077261:Carvedilol; D004280:Dobutamine; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism; D049268:Positron-Emission Tomography; D011379:Prognosis; D011412:Propanolamines / Q000627:therapeutic use*; D019275:Radiopharmaceuticals; D011943:Receptors, Adrenergic, beta / Q000378:metabolism*; D013318:Stroke Volume / Q000187:drug effects
D000319:Adrenergic beta-Antagonists; D002227:Carbazoles; D002250:Carbon Radioisotopes; D011412:Propanolamines; D019275:Radiopharmaceuticals; D011943:Receptors, Adrenergic, beta; D000077261:Carvedilol; D004280:Dobutamine; C033394:CGP 12177