Dextran subs for contrast in OCT with similar results

Dextran offers an inexpensive and possibly safe alternative to standard contrast dyes used in coronary optical coherence tomography (OCT) imaging, according to a feasibility study published in the Nov. 1 issue of Catheterization and Coronary Interventions.

OCT allows interventional cardiologists to assess coronary plaque morphology with high resolution but it requires radiologic contrast media that can lead to complications such as contrast-induced nephropathy or allergic reactions. Low molecular weight dextran, which is used clinically, might perform the same blood displacement function as these agents.

Kyle Frick, MD, and colleagues at North Texas Health System tested the idea with a single-center study that enrolled 26 consecutive patients in 2012 and 2013 who were candidates for coronary angiography with OCT. They performed OCT imaging with either the contrast media iodixanol (GE Healthcare) or dextran-40. They used manual injection and corrected area and length measurements to adjust for dextran’s refractive index.

They obtained 1,709 cross-sections each with contrast and dextran. They found that imaging results were similar for both approaches, with a high level of correlation between measurements by contrast or dextran. Frick et al reported no complications as well.

They noted that contrast media is expensive. “Use of dextran instead of contrast can render OCT imaging safer and less costly,” they proposed. “This may be of particular benefit among patients with baseline renal insufficiency and patients in whom multiple OCT image acquisitions are required.”

In an accompanying editorial, Anand Prasad, MD, and Jennifer Phipps, PhD, both of the University of Texas Health Science Center in San Antonio, argued that the sample size was too small to provide safety signals. Still, they wrote, the North Texas team has built a “strong case for dextran use during OCT imaging to reduce the unnecessary administration of contrast dye.”