CARDIAC SYMPATHETIC DENERVATION IN PATIENTS WITH CORONARY-ARTERY DISEASE WITHOUT PREVIOUS MYOCARDIAL-INFARCTION

Myocardial infarction damages sympathetic nerve fibers coursing throug h the infarct zone. In this study we investigated whether coronary art ery disease without myocardial infarction results in sympathetic dener vation. We examined 12 patients without a history of previous myocardi al infarction and 19 postinfarction patients. I-123 metaiodobenzylguan idine (MIBG) and technetium-99m sestamibi (MIBI) single-photon emissio n tomography were conducted at rest to determine the extent of denerva ted myocardium and the extent of myocardium with reduced perfusion, re spectively. In addition, myocardial perfusion during exercise was asse ssed with MIBI. A MIBG or MIBI defect was determined as being regional uptake of less than or equal to 30% of the maximal myocardial activit y. All but 1 patient without previous infarction had MIBG defects. MIB G defects (10.3 +/- 8.5% of left ventricular moss) were significantly larger than MIBI defects at rest (2.4 +/- 3.2%, p <0.001) and during e xercise (4.8 +/- 6.1%, p <0.05). In multiregression analysis, the size of an MIBG defect was associated with severity of coronary stenoses ( greater than or equal to 90% of lumen diameter; p <0.05), but not with age, number of significant stenoses (greater than or equal to 50% of lumen diameter), left main disease, functional doss, left venticular e jection fraction, angina pectoris, maximal ST depression, or mean work load during exercise test. MIBG and MIBI defects were significantly la rger in patients with severe coronary stenoses than in patients with m oderate stenoses (50% to 89% of lumen diameter) (16.4 +/- 8.9% vs 6.0 +/- 5.2% [p <0.0-5] and 5.0 +/- 3.1% vs 0.6 +/- 7.3% [p <0.001], respe ctively). The size of MIBG (16.1 +/- 8.9%) and MIBI defects (7.3 +/- 6 .5%) at rest in postinfarction patients did not differ from patients w ith severe stenoses. Our study demonstrates that cardiac adrenergic ti ssue is very sensitive to ischemia and that regional cardiac sympathet ic denervation can occur in patients with stable coronary artery disea se without previous myocardial infarction. (C) 1997 by Excerpta Medica , Inc.