FAST ROTATING ATHERECTOMY CATHETER TIP INHIBITS PLATELET-AGGREGATION AND ATP RELEASE - A STUDY USING PLATELET-RICH PLASMA

The interaction of atherectomy devices with the arterial wall is the f ocus of many studies, but their effect on the surrounding blood is lar gely unknown. This is a detailed investigation on the effects of a rot ational atherectomy device with a fast rotating tip on platelet struct ure and function. Platelet-rich plasma (PRP) was obtained from six vol unteers, divided into 5 mL samples, and subjected to the atherectomy t ip rotating at 20, 40, or 80 thousand rpm for 30 or 60 seconds. Platel et aggregation to collagen or adenosine diphosphate (ADP) was obtained in all samples by means of a dual-chamber optical aggregometer. The f ast rotating catheter tip caused marked inhibition of platelet aggrega tion to both collagen and ADP. The maximum extent of aggregation was r educed 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 an d 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 r atio remained unchanged) to account for these phenomena. Furthermore, transmission electron microscopy showed no significant platelet disrup tion or release of granules, and little signs of activation were seen even after addition of collagen. This is the first study to demonstrat e that exposure to a fast rotating catheter tip inhibits in vitro plat elet aggregation and ATP release. There were no apparent loss of integ rity of platelet structure, release of granules, or formation of plate let aggregates. This phenomenon and its clinical implication justify f urther investigation.