Hi. Percentage block is important, but more important is how well your fathers heart is functioning measured by the Left Ventricular Ejection Fraction
(LVEF). If the LVEF is good and your father's symptoms are not too worse, then angioplasty
(with drug eluting stents) is a good solution. However if the LVEF is bad, go for CABG (Bypass Grafting). Your Doc is the best person to decide. Take Care.