Tortuosity as an index of the age and diameter increase of coronary collateral vessels in patients after acute myocardial infarction.

A possible correlation among increase in diameter, lengthening or tortuosity and age of bypassed obstruction was investigated in coronary arterial collateral vessels. In 35 autopsy patients with a myocardial infarct of known age, as determined from clinical history and pathologic demonstration of an infarct of consistent age in the distribution of an obstructed vessel, 140 collateral vessels were identified in postmortem arteriograms and measurements made of their diameter and tortuosity. Multivariable regression analyses showed that collateral diameter and tortuosity increase with greater time after the infarction. It is suggested that identification of tortuosity in a coronary vessel may provide an indication that it functions as a collateral channel and of the degree of its dilatation and the time it has been a collateral channel. The lengthening that produces tortuosity probably arises from the same relaxation of medial tension that induces dilatation as a result of increased blood flow.