Can ulnar artery velocity changes be used as a preoperative screening tool for radial artery grafting in coronary artery bypass?

Radial artery harvesting for coronary revascularization may result in digit ischemia if collateral circulation is inadequate. The purpose of this study was to compare changes in ulnar artery flow velocity during radial artery compression (RAC) with changes in first- and second-digit pressures during RAC, a previously validated predictor of digital ischemia. Photoplethysmography was used to measure first- and second-digit arterial pressures before and during RAC on 80 extremities. Color flow duplex imaging was used to measure distal ulnar artery peak systolic velocity before and during RAC. Seventy-eight of eighty extremities had a slight increase in ulnar artery velocity with RAC. There was no correlation between ulnar artery velocity changes and digit pressure changes. Measurement of ulnar artery velocity during RAC is not a useful predictor of digit pressure changes. Measurement of segmental upper extremity pressures with first- and second-digit pressure measurement during radial artery compression should remain the preferred preoperative screening tool for radial artery harvest prior to CABG.

In vitro and in vivo characterization of a 99mTc complex with tris(hydroxymethyl)phosphine (THP).

The water-soluble, monophosphine ligand tris(hydroxymethyl)phosphine (THMP) was complexed with 99mTc. The 99mTc-THMP was formed in high radiochemical purity by simply mixing 99mTcO4- with THMP over a wide pH range. In vitro and in vivo studies indicated the complex to be highly stable under the respective conditions. HPLC analysis indicated a singular species with a retention time identical to the known [ReO2(THMP)4]1 complex. Results show that the hydroxymethylphosphine functionality is attractive for use in designing new 99mTc radiopharmaceuticals.