Detection of coronary collateral flow by a Doppler-tipped guide wire during coronary angioplasty.

Coronary collaterals may not be apparent during routine coronary angiography or during coronary angioplasty as a result of a variety of physiologic and anatomic factors.‘-” The dynamic nature of the collateral circulation has been demonstrated by newly appearing angiographic collaterals during contralateral vessel occlusion.3 An elevated coronary occlusion wedge pressure during angioplasty balloon inflation has also been an accepted indication of acutely recruitable collateral circulation6 In some patients coronary collateral flow may reduce ischemia by providing distal perfusion pressure equal to that of the systemic circulation through angiographically insignificant collateral