Yes, unfortunately heart disease is a chronic, lifelong, progressive, and often recurrent disease. Having had bypass surgery corrects the blood flow at the time of surgery, but, over time, the same processes that caused fatty plaques to deposit in the walls of the original or natural arteries will continue to occur in the bypass arteries. Some bypass arteries, transplanted veins, are more susceptible than others to this process. Bypass arteries that used to be actual arteries (like the Left Internal Mammary Artery or LIMA, an artery that supplies blood to the muscles and structures of the chest wall, and can be re-directed in open heart surgery to feed the LAD--Left Anterior Descending Artery--at the front of the heart) will usually hold up better over time, but even these can eventually succumb to plaque formation. You mentioned that your husband is significantly obese and is very sedentary, which are factors that work against him avoiding further coronary artery disease. It is often difficult for people with Parkinson s Disease and also with chronic severe back pain to get enough aerobic exercise safely, so I understand the difficulties he would have with this. A few questions I have for you are: is he seeing a Cardiologist or a Primary Doctor on a regular basis? Is he diabetic? Is his cholesterol optimally controlled or not? Is he on a statin drug (to lower cholesterol levels, and which have been proven to prevent MI s, cardiovascular deaths, and recurrent plaque formation in people who have had prior cardiac events or interventions)? Does he smoke cigarettes? The answers to those questions above will be important in knowing whether your husband s medical situation is optimized to prevent the development of new arterial blockages in either his 12-year-old bypass arteries or even worsening disease of his natural arteries. One way to find out if he has developed significant blockages in any of his heart s arteries, despite maybe being unable to exercise or walk long or fast or far enough to develop angina would be to have a Nuclear Stress Test, in which his doctor would give him a medication in his IV that makes the heart think it is exercising, followed by a radioactive imaging agent that creates a picture of the blood flow in his heart. That would tell us how his blood flows under exercise or stress conditions compared with his natural or resting state. If his blood flow seems abnormal, his doctor might adjust his medications or might refer him for an angiogram to see whether and where and how severe the blocked arteries might be. He wouldn t necessarily require a repeat open heart surgery if new blockages are confirmed, since the more common situation nowadays is that he could be treated with ballooning and/or stenting of his blocked artery if that is what would be discovered. Good luck, and write back if we may be of further help to you, or if you have any further questions about anything I ve said above.