Blood flow velocity effects and role of activation delay time on growth and form of platelet thrombi.

Mural thrombi are composed dominantly of platelets and develop under a blood flow. Portions can break off and are carried in the blood flow as emboli. Thrombus growth rates are affected by the velocity of the blood flow, but they do not simply increase with it, they exhibit a maximum, with subsequent decrease.

The artificial lung facility at Brown: more than a dozen years with Pierre Galletti.

Beginning in 1969, Pierre Galletti and his colleagues established a laboratory at Brown University, which, initially and for many years, was involved with artificial lungs. Various projects budded out of this, including the following: the establishment of standards for oxygenator performance, which anticipated Food and Drug Administration requirements; studies of thrombosis and other pathologies, which could be reduced by design changes; long-term, pumpless arterio-venous (A-V) bypass; early hybrid pancreas and other artificial organs; implantable lungs; and spin off companies. The current report outlines the history, philosophy, collaborations, and major results of the laboratory, as well as how the principal investigators simultaneously moved into research areas outside of artificial lungs in the late 1980s.

Elliptic delamination as an early stage in atherosclerotic plaque evolution: fluid mechanical aspects.

Relatively little attention has been given to vessel wall mechanics in interaction with the pulsatile fluid motion of blood in the epicardial coronary arteries which are prone to atherosclerotic plaque development. Theories for lipid transport by convective effects, while appealing in many ways, do not serve to explain the predominantly bounded, elliptic profiles of atherosclerotic plaques when examined en face at gross autopsy. This paper outlines how structural-mechanical concepts relating to plaque shapes (starting from the shapes available even with isometric shell peeling to create the cavities typical of early plaques) can be combined with understanding of the blood pressure distribution which develops in the vicinity of a predominantly T-junction in a blood vessel to modulate and interact in shape formation by cyclic, local flexure.

Biomechanics of plaque rupture: progress, problems, and new frontiers.

Plaque rupture has become identified as a critical step in the evolution of arterial plaques, especially as clinically significant events occur in critical arteries. It has become common in the past dozen years or so to consider which plaques are vulnerable, even though not yet ruptured. Thrombotic events have remained significant, but in a context where they are seen as being triggered often by plaque rupture.