ROLE OF SIDE HOLES IN GUIDE CATHETERS - OBSERVATIONS ON CORONARY PRESSURE AND FLOW

When performing coronary angioplasty, guide catheter intubation of the ostium often leads to a damping of the pressure tracing, In contrast, when a guide catheter with side holes is used, the pressure tracing i s most often superimposable to the pressure wave recorded through the side arm of a femoral artery sheath introducer. This pressure wave giv es the reassuring impression of normal hemodynamics in the coronary ar tery. To illustrate the role of guide catheter side holes and that gui de catheter pressure does not necessarily equal the actual coronary ar tery perfusion pressure, we report observations on trans ostial pressu re gradients at rest and during increased coronary flow rates. An abbr eviated in vivo study of side holes on the maximal achievable blood fl ow, employing timed blood flow collections in 7F and 8F side hole guid e catheters, was made in 10 patients, At high mean aortic pressure lev els, the blood flow through the side holes did not exceed 80 and 60 mL /min for 8 and 7F guide catheters, respectively. These observations su ggest that, under some conditions, the guide catheter may produce a re sting or hyperemic trans-ostial gradient and that the flow provided on ly by the side holes of guide catheter is limited, Guide catheter inte rference with normal flow should be considered in interventional proce dures even when arterial pressure appears normal. (C) 1994 Wiley-Liss, Inc.