Switched to vegetarianism after stenting. Only result was fall in BP to 85/55 and feeling sick. Back to eating fish and chicken, of course in limited quantity.
Veganism: Switched to vegetarianism after... - Healthy Eating
Veganism
This article has a few useful suggestions on low blood pressure and what you eat.
Moving towards veganism can take time to adjust for some people. The gut microbiome is tuned to what you are used to eating so when a change happens it can take time to adjust.
As an example let me talk about legumes. Some people try swapping a meat-based diet for legumes almost overnight and feel symptoms such as bloating, lots of wind and whatever else. The wind in most people disappears after a few days. Bloating and other uncomfortable feelings really means you should take a step back and slow the change down. So eat smaller portions of pulses, ensure they are properly soaked, perhaps even sprout them. (Sprouting not only makes more food for the cost, but also makes legumes incredibly healthy.)
When I gave up cheese I took three months over the process by limiting my cheese choices bit by bit.
There are other challenges, for instance the mentality of a non-vegan lifestyle is to calorie count. For 99.9% of people when going vegan calorie counting is what you do not want to do, just eat until you are satiated at each and every meal. This is not some trivial point. Almost every resource you look at will tell you to control your portions. Especially as you move from a vegan diet towards a whole food diet portion control is just what you do not want to do - and the weight (for that 99.9%) will slowly normalise towards your BMI - even without exercise.
Any risk of low blood pressure needs monitoring by a doctor.