Alternative method for accessing the target coronary artery in patients with difficult coronary anatomy: exchanging the diagnostic catheter with a guiding catheter.

We report a method of the placement of the guiding catheter in two cases in which the diagnostic catheter could be easily engaged to the target coronary arteries but not a guiding catheter, due to a distorted aortic sinus and an osteal subtotal occlusion, respectively. After engaging to the target coronary artery with a diagnostic catheter, a coronary guidewire was advanced through the diagnostic catheter, and exchanged with a guiding catheter over the guidewires. The procedures were completed with success.