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We report on treatment of a patient in whom failure to deploy the distal portion of a Palmaz-Schatz stent occurred but was not recognized. After an unstable course, the patient underwent repeat coronary angiography, at which time the stent was rewired and redilated. Full deployment of the stent with restoration of TIMI grade 3 flow was achieved. The putative cause of the problem, incomplete deployment of the stent because of inadvertent advancement of the stent delivery sheath, should be avoided, and needs to be recognized if it occurs. Crossing and redilating the stent is possible, although technically difficult.

A 35-yr-old woman with known valvular heart disease presented with acute myocardial infarction. Angiography demonstrated a totally occluded distal left anterior descending coronary artery. Though initially successful, angioplasty ultimately failed to maintain arterial patency, leaving a more distal total occlusion after several balloon inflations. In spite of this, PTCA possibly provided a more localized infarction via a peripheral mobilization of the embolus.

A formal analysis of the error associated with the use of radiographic diameter measurements in estimating the luminal area of an elliptically-shaped coronary cross-section was performed. When two views are available, the maximum potential error was found to decrease rapidly as the angle between the views increased to 90 degrees, but this error was small (less than 25%) for orthogonal views only for mild degrees of ellipticity (major/minor axis ratio less than 2). Since, for each successive doubling of the number of radiographic views, a stepwise reduction in the potential error by an approximate factor of only one-half was found, a large number of views is required to eliminate the potential error associated with diameter assessment of highly elliptical lumena.

Reproduction of a human atherosclerotic lumen within the arterial lumen of an intact animal would facilitate angiographic and hemodynamic studies of stenoses. Accordingly, a male silicone rubber cast of a human atherosclerotic lumen was obtained from a cadaver artery, and a thin-walled replicate arterial phantom was constructed from the cast by use of a rapidly polymerizing liquid plastic. The casting properties of both materials were such that the topography of the arterial lumen was duplicated precisely in the phantom with 20 x microscopic detail preserved. The phantom was coated with a banzalkonium-heparin solution and introduced over a guidewire into an epicardial segment of a coronary lumen of the dog. Similarly, a larger phantom was placed within the dog femoral artery either directly via an arteriotomy or indirectly via a catheterization technique. Since the plastic material used to make a phantom had the same radiographic density of tissue, the angiographic appearance of an intra-arterial phantom was that of a human stenosis.