Effect of contrast injection on coronary artery pressure and dimension during angiography

Digital coronary angiography and intracoronary pressure recordings were performed in 17 patients to quantitate the mechanical effects of contrast injection on coronary artery pressure and diameter in arterial segments free of stenotic lesions at the moment of image acquisition. A progressive increase in intracoronary pressures by 9.2±6.6 mmHg for a power injection rate of 2.5 ml/s, 14.4±10.9 mmHg for 5 ml/s and 23.9±24.2 mmHg for 10 ml/s was documented Corresponding diameters were distended by net -0.13 to +0.65 mm (p<0.005) during the injection, as evaluated by digital quantitative coronary angiography (DQCA). These mechanical phenomena result in changes of coronary artery, diameter from -4.9% to +19.5% at 10 ml/s (p<0.005) and unmask the individual compliance of the arterial wall. It is concluded that coronary dimensions obtained from DQCA critically depend on the intracoronary pressure with contrast medium injection. It may represent an additional source of error in the analysis and interpretation of clinical angiographic studies