My personal anecdote - I've been on blood pressure medications since my senior year of high school.
Since then, I've had one hospitalization, seen four cardiologists, two nephrologists, many trips to the ER, regular check ups to keep my blood pressure in check. This spans over 25 years.
March, I had another really high blood episode that landed me in the ER. The cardiologist wants to bump my meds yet again because basically he has nothing else for me.
I was really frustrated.
I start to to research, and stumble upon Hyperaldosteronism. I get a referral to an endocrinologist. The blood test shows that I have a really high Aldosterone/Renin ratio. Along with low potassium (another sign). I have a CT scan, there's a nodule on my right adrenal.
Tomorrow I am having an AVS, an adrenal ventricular sampling, to tell which adrenal(s) are overproducing.