The effect of severity of coronary artery obstructive disease and the coronary collateral circulation on local histopathologic and electrographic observations in man

Abstract

The relationship between both angiographically defined proximal coronary obstructions of varying severity and coronary collaterals and the subserved left ventricular myocardium in living man is incompletely understood. Therefore, their electrophysiologic and histopathologic characteristics were evaluated in 48 patients at the time of open heart surgery. Of 28 areas supplied by ≥90 per cent obstructed arteries, the histopathology in 12, based on local biopsy specimens, was normal; in the remaining 16 there was significant muscle loss. In contrast, of five areas with < 90 per cent obstructions, four were normal (p < 0.05). Epicardial electrograms recorded from 55 areas with ≥90 per cent obstruction showed R waves in 42 and Q waves in 13. Of 24 areas with < 90 per cent obstruction, there were R waves in 21 and Q waves in only three. When areas supplied by collaterals were compared to those without angiographically demonstrable collaterals, the frequency of both histopathologic abnormalities and epicardial Q waves was similar. In addition, the effect of collateral blood flow to vessels with similar degrees of obstruction was compared. Of seven areas with ≥ 90 per cent obstructions and collateral supply, the histopathology was normal in two, and there was muscle loss in five. Of 21 areas with >90 per cent obstructions without collaterals, 10 were normal whereas 11 showed muscle loss. Similarly, in 16 areas with collaterals, epicardial electrograms showed R waves in 11 and Q waves in five; whereas of 39 without collaterals, there were R waves in 31 and Q waves in eight. Thus, ≥ 90 per cent coronary obstructive lesions are associated with both more muscle loss and epicardial Q waves than lesser obstructions. No beneficial effect of collaterals was demonstrable.