 After using the JR4 6-French catheter, nitroglycerin was administered because of the possibility of ostial spasm, and following that, we used a 5-French JR4 catheter for additional cineangiograms of the right coronary artery. 
After using the JR4 6 - French catheter , nitroglycerin was administered because of the possibility of ostial spasm , and following that , we used a 5 - French JR4 catheter for additional cineangiograms of the right coronary artery .