There have been four large prospective trials that have been recently reviewed, all demonstrated decreases when hormone replacement therapy was started at the mean age of 53 years. Early hormone replacement therapy is protective; it prevents arterial plaques and coronary arterial disease, but will not prevent or reduce already existing disease.
The cardiovascular risks are improved with use of natural progesterone in comparison to synthetic Progestins. Synthetic progesterone or progestins are not good. The estrogen only arm identified a decreased risk of coronary artery disease, and that progestins decrease the cardio protective effect of estrogen. Bioidentical Progesterone decreased LDL’s (JAMA 1995), inhibits vascular smooth muscle (Journal Vascular Surgery 2002). Whereas synthetic Progestins actually stimulated smooth muscle proliferation in coronary arteries, Bioidentical Progesterone vasodilates, increases nitric oxide, and does not increase C-Reactive protein.
Synthetic progestins oppose vasodilatation (Circulation 2001), and increases C – reactive protein (Circulation 1999). There is very strong data to support the use of bioidentical progesterone in protecting your heart instead of the synthetic progestins ( Prempro™, Provera™), which increase the risk of heart disease.
A recent review of the WHI study looking at the long-term effects in patients who only received Premarin, demonstrated no significant long-term benefit in regards to coronary artery disease, an increased stroke risk, and increased dementia in women only receiving Premarin.
From the standpoint of the heart, the Journal of American Epidemiology 2002 published a study that identified if you hold onto your natural hormones longer that you will lower the risks of cardiovascular disease. The reason for that is that bioidentical estrogen vasodilates (Journal of Clinical Endocrinology and Metabolism), decreases sympathetic outflow, and decreases vascular proliferation (Circulation 2001).
Bioidentical Estrogen will lower blood pressure (Journal of Clinical Endocrinology 2006). Transdermal estrogen causes a significant reduction in blood pressure. This data is not only very relevant, but also very important in the daily management of blood pressure in women. Often women are told to stop there Estrogen because there blood pressure is elevated.
This is certainly the case with the synthetic progestin and the conjugated equine estrogen, but if you look at the bioidentical hormones administered, especially the transdermals there is a protective effect on blood pressure. In addition, the transdermals have a protective effect on thrombosis, as opposed to the synthetic preparations.
Transdermal Estradiol has a beneficial effect on fibrinogen, lowers the clotting and fibrinolytic pathways. The Mayo clinic study demonstrated a reduction in Calcium content and arterial plaques size with Estrogen therapy.