Fast rotating atherectomy catheter tip inhibits platelet aggregation and ATP release: a study using platelet-rich...

The interaction of atherectomy devices with the arterial wall is the focus of many studies, but their effect on the surrounding blood is largely unknown. This is a detailed investigation on the effects of a rotational atherectomy device with a fast rotating tip on platelet structure and function. Platelet-rich plasma (PRP) was obtained from six volunteers, divided into 5 mL samples, and subjected to the atherectomy tip rotating at 20, 40, or 80 thousand rpm for 30 or 60 seconds. Platelet aggregation to collagen or adenosine diphosphate (ADP) was obtained in all samples by means of a dual-chamber optical aggregometer. The fast rotating catheter tip caused marked inhibition of platelet aggregation to both collagen and ADP. The maximum extent of aggregation was reduced from 85% +/-2.8 in control to 46% +/-4.8 with collagen (p<0.01) and from 86.1% +/-6.9 to 25.1% +/-4.3 with ADP (p<0.01). The rate of aggregation (measured at 4 minutes) dropped from 81.3% +/-2.7 to 40% +/-4.5 and from 73.9% +/-8.5 to 12.5% +/-2.6 (p<0.005) with collagen and ADP, respectively. These effects were related to rotating speed and duration of exposure. ATP release in response to collagen fell from 2.63 +/-0.13 nMol in control to 0.7 +/-0.1 nMol, p<0.001 after exposure to the rotating tip. There was no significant change in platelet count, nor was there formation of platelet aggregates (platelet aggregate ratio remained unchanged) to account for these phenomena. Furthermore, transmission electron microscopy showed no significant platelet disruption or release of granules, and little signs of activation were seen even after addition of collagen. This is the first study to demonstrate that exposure to a fast rotating catheter tip inhibits in vitro platelet aggregation and ATP release. There were no apparent loss of integrity of platelet structure, release of granules, or formation of platelet aggregates. This phenomenon and its clinical implication justify further investigation.