PATHOPHYSIOLOGY OF CORONARY COLLATERAL CIRCULATION IN HUMANS

The functional relevance of coronary collaterals in humans has yet to be fully explored. Several studies demonstrated a protective role of c ollaterals in patients with coronary artery disease. On the other hand , negative aspects of well-developed coronary collaterals have been re ported, e.g. a higher rate of restenosis following coronary angioplast y, or a redistribution of blood via collaterals away from the myocardi al area in need towards normally perfused areas (coronary steal). In t he past, the coronary collateral circulation has been assessed only qu alitatively, using visual angiographic or nuclear imaging methods. Wit h the recent advent of intracoronary Doppler and pressure-transducers, quantitative assessment of functional parameters of the coronary circ ulation has become feasible. This article reviews ongoing research in the field of coronary collaterals in humans, concerning their exact de termination, the positive and negative aspects of their structure as w ell as their functional aspects.