My my husband had a heart attack 3 months ago and had 4 stents inserted. He is on various medications 100 mg of aspirin daily is one. He is 50 years old. 8 days ago he starting passing blood in his urine to the point that his urine resembled cola. The next day he had severe abdominal pain and that afternoon passed a kidney stone.His urine returned to almost normal colour within a couple of hours of passing the stone and has been fine until yesterday, when the blood in the urine returned, not quite the cola colour but very red. Hospital tests showed not stones . His blood and urine tests showed no infection and also that the kidneys were working normally. At lunchtime today, urine has almost returned to normal colour but the pain in the lower abdominal has appeared again and has continued to get worse in the past few hours. Not sure what to do, hospital seemed to indicate yesterday that we were making a fuss about nothing.just wondering what maybe it could be.