Q: What is the average time grafts take to get re-blocked after a bypass surgery? I had a triple by-pass three years ago. Since that date I have stopped smoking and eating any animal products and jog for 45 minutes 6 days a week. Is there a chance for my arteries to get clogged again? If so, after how many years?

A:There are no mathematical rules dictating this phenomenon. Re-blockage is multi-factorial. Venous grafts tend to block much faster than arterial grafts. 10% of venous grafts block within the 1st one year and thereafter 3-5% block every year. So that by 10 years nearly half of them are blocked. The results of arterial grafting are much better. Internal mammary artery tends to remain open in 90-95% of patients at 20 years. We don't have such long-term results with other arterial bypasses but even these are likely to be in the range of 80-90% at 10-15 years. Another factor, which is important, is the control of risk factors. I am happy to note that you have stopped smoking and eating animal products and that you are jogging 45 minutes every day. Those who don't look after their risk factors tend to have blockage much earlier. In a nut-shell, patients with venous bypasses are likely to get 10-12 years on an average from their bypass surgery and those with arterial bypasses must get at-least 15-20 years from their bypass surgery.