My Son Had A Triple Bypass At 35 Can Certainly

My son had a triple bypass at 35 can certainly at 18....he is 43 now a days is experiencing shortness of breath off and on for 3 weeks and recently went to ER with it progressingredients. Blood markers for heart aND blood clots were negative. He has followed up with new PCP who thinks it's nothing. Any suggestions. He has been having increased BP a day indibestion6