For a perspective, normal EF is 55 to 75%. Chronic hypertension and aorta stenosis can/will increa\se heart wall thickness that is a physical change to tissue structure with or without a change in the radius of the heart chamber.
The physical change of the heart tissue generates a greater contractile force and accounts for the over 75% for the EF. Your condition is not severe according to your post, but control of afterload (high blood pressure, etc.) to decrease the workload for the heart can/will slow any progession and possibly reverse.
I had severe pre-eclampsia with the first pregnancy, had to deliver prematurely, My bp was 110/62 with both pregs until the eclampsia kicked in. My father had a diseased kidney removed 30 yrs ago, all he remembers is that it had cysts.
check your BP in various positions. Did you have HTN in pregnancy that did not go away once you delivered? considere to have your kidneys scanned (doppler) and see some one who specializes in HTN in young people especially women in child bearing age.