Telescoping catheter technique for enlarged aortas.

Selective coronary angiography in severely dilated ascending aorta is technically challenging and sometimes impossible. The Terumo "five-in-six" system uses an extra long 5Fr guide catheter in a standard 6Fr guide catheter, so that the tip of the 5Fr guide catheter protrudes beyond the tip of the 6Fr catheter allowing an extra reach. This system has been used successfully to advance balloon catheters across chronic total occlusions (Takahashi et al, Catheter Cardiovasc Interv 2004;63:452-456) and stent delivery beyond proximal obstruction point (Mamas et al, Catheter Cardiovasc Interv 2008;71:358-363). We describe the successful use of this system in an atraumatic manner for selective coronary angiography in a patient with a severely dilated ascending aorta.