My angiography done last year due to false +ve stress test was ok.i.e no cardio issues were seen. i am 56, is it ok for me to sprint at this age or there can be potential risks involved?

Like all exercises, one should start slowly and gradually increase as tolerated. One should do well but if symptoms which triggered the initial Stress test evaluation reoccurs, then one should see a Cardiologist.

Generally speaking, if there is no coronary artery disease on angiography, or any other indicators of cardiac disease, typically there would be no limitation to any sort of physical activity as tolerated. Certainly, people in their 50's are not typically as flexible as when they were younger, so ensure proper stretching to reduce injury.