Simply put a preexisting condition is ANY medical condition which existed prior to purchasing your insurance.
High Blood Pressure is common but it is a medical condition that can lead to many complications such as stroke, etc. So that is a pre-existing medical condition.
When you buy insurance you have to fill out a medical history and provide information about any and all medical conditions you have been treated for in the past and currently.
You can ask for clarifications in writing if any of those conditions or complications as a result of that medical condition is excluded in the coverage.
If the insurance company will not put it in writing what is excluded then they is not reputable.
You can check the companies and their ratings and consumer complaints online with the Better Business Bureau
This Consumer Report link gives you some helpful tips
This link gives you reviews of many different insurers
You have to do your homework and use the internet to research reputable companies and then contact them and get a sample policy and email them what your medical conditions are past and present and ask if you would be excluded from benefits if you have a medical emergency while travelling in the US and it is related to those conditions.
That is the best you can do.
Even I ran into an issue with having my airfare refunded when I had to have emergency back surgery and I had a history of spinal disease in the past. I didn't ask prior to buying the policy for a sample policy and didn't read the fine print before buying. Fortunately, I was not excluded becase of the pre-existing condition, but when I read the fine print even as a lawyer I thought I made a mistake and would not be refunded my ticket cost of several thousand dollars.
So be prepared for the worst and hope for the best. What I can tell you from my experience with insurance companies, all of them, they are in the business of making money and paying claims cuts into their profits so if there is a way to get out of paying they will!
All the best and pray for good health.
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