Assessment of coronary blood flow and velocity in the catheterization laboratory

Abstract

Over the past two decades, radiographic, inert gas washout and catheter techniques have been developed which allow measurement of relative and absolute coronary blood flow. Although contrast medium is not an ideal indicator substance for application of the Stuart-Hamilton, Kety-Schmidt, or Sapirstein principles, transit-time methodology has been successfully employed through combination with digital radiographic techniques. Parameter images have been utilized to display coronary flow reserve data. Scintigraphic assessment of Xenon-133 and catheter measurement of hydrogen washout allow determination of regional myocardial perfusion using the Kety-Schmidt principle, although inaccuracies at low and high flow states have been reported. The most widely used approaches use coronary sinus thermodilution and intracoronary Doppler catheters. Impedance catheter and guidewire techniques have recently been introduced. The latter two are regionally specific, and promise to provide assessment of coronary blood flow simply and inexpensively in the catheterization laboratory.