To the Editor.—We believed that our methods of angiography were quite standard and did not warrant a detailed disclosure. In the interest of brevity, these are the details: (1) site of entry: retrograde femoral catheterization or infrarenal translumbar aortogram needle; (2) rate of injection: 6 ml/sec, usually for three seconds; (3) type of injection material: diatrizoate (Hypaque 60) meglumine; (4) time sequence at the level of the runoff: four-second delay, one per second times seven exposures, one every two seconds times four exposures, one every three seconds times seven exposures, for a total of 40 seconds.
We have utilized vasodilators or reactive hyperemia only when we did not demonstrate runoff suitable for bypass. Based on my recollection, none of the patients in this series were deemed to be operable only after the performance of ischemic studies.
All of the patients in whom we have performed postoperative sequential angiography (as