What options have you been offered and with what reasons?
Did they say exactly what had happened to the stent, something more meaninful rather than just "failed"?
About 58% of patients have restenosis after about 8.9 months (the statistic can be further refined to what type, etc.). A failure would be restenosis (blockage within the lumen of vessel) and primarily due to overgrowth of tissue. Drug eluding stents have a better record regarding restenosis and normally would last longer than 7 years, and if less it may be considered a failure as would a bare metal stent.
High blood pressure can be an underlying cause for restenosis, and if possible it should be brought into a range below 120/80.
There can be another stent placed inside the current stent for some occlusions, and for just one occlusion it may be a big jump to have a bypass. Are there any symptoms such as chest pain, shortness of breath, fatigue, etc. Sometimes medication can relieve symptoms and intervention is not needed. You have not provided much info such as age, symptoms, general health etc. and these factors would be a consideration for any by-pass.