hello. thanks for posting here. i have noted his history. what is important is whether he had sympyoms during the low bloid pressure episode. Angioplasty directly cant cause low blood pressure. but since he has got an angioplasty that means he has some heart issues which can cause low blood pressure. so again if he had symptoms like dizziness, feeling weak, loss of consciousness, sweating, then it is a matter of concern. Another factor here is that since he has underwent an angioplasty, he must be on blood pressure medications. some medications which keep the heart rate in control can also cause low blood pressure. So in short there are many factors that should be evaluated here. If he has another low blood pressure episode consider stopping or decreasing dose of one blood pressure medication. Also if the reading was from a home electronic BP monitor please get it checked. Alternatively you can also get your pressure checked with the same machine to check its accuracy. (only if it is an electronic machine). thank you