Unable to walk 100m, general weakness.

Hello Dr. .... My father is 74yrs old . He is suffering from diabetes (20yrs), BP(5yrs), constipation and general fatigue and weekness. He has this problem of chest pain whenever he walks for around 100-150 m since last 2 yrs. When he takes rest for sometime then there is relief and he can walk a similar or lesser distance again. Recently, we visited Dr Purushottam LAL at Metro heart institute, Noida. He suggested Angiography, as he does the shorter version of catheter angiography through the arm. I checked on the internet there is non-invasive angiography called 64/128slice CT angiography. My question is, should we go for the 64/128slice CT  or  (through arm) catheter Angiography, and why ? Your kind response is awaited. -Devesh