Clot lysis of variant recombinant fibrinogens confirms that fiber diameter is a major determinant of lysis rate.

Previous studies have suggested that clots with thinner fiber diameter lyse at slower rates than clots with thicker fiber diameter. We examined lysis of fibrin clots formed from three variant fibrinogens, each with substitutions in the N-terminal region of the B beta chain. When we measured lysis as the rate of decrease in turbidity at 350 nm, we found that the rate of lysis was slower than normal for clots with thinner fibers. We noted, however, that the time to complete lysis was the same for all clots. Thus, when the data were considered as the percent of lysis with time, we found that the curves were the same as normal. We suggest that a complete and accurate characterization of clot dissolution requires comparison of normalized lysis rates.