Respected user, hi I evaluated your query thoroughly. *Arterial blockage has many compounding factors to be taken into considerations : - age of patient - associated comorbid conditions of HBP, Diabetes, PVD, Hypercholesterolemia - mobility of patient - diet - exercises - medications efficacy - immune response of host - alochol / smoking - calcification tendencies of vessels - many more. *So any of the above factor not in favor of vessel leads to repeated blockages despite of our all efforts with best stents, medicines etc. Hope this clears your doubt. Thanks for using Health care magic & keeping trust in our medical services. Regards dear take care.