I am not a doctor, but I have done a lot of reading about the effects of cabin pressurization, since I am a flight attendant and am concerned about the potential effects to my own body. The pressurization causes all internal organs and vessels to expand and then constrict upon descent. I believe this could cause a problem for you as the plaque in your arteries may swell and further occlude your vessels. Best to check with your doctor and see what s/he says before taking any long flights.