PAH is associated with an imbalance of 3 natural substances in your body. When balanced, each of these substances works in its own way to help blood flow freely through your blood vessels. Currently, there is no test to determine which substance is out of balance.
Too little Prostacyclin
Prostacyclin works in different ways within healthy blood vessels. It helps to open arteries (dilation), helps prevent blood clots from forming in blood vessels and works to slow down rapid cell growth (smooth muscle proliferation).
Too little Nitric oxide
Nitric oxide does many different things in the body, including helping control blood pressure by opening arteries (dilation) when needed.
Too much Endothelin
Endothelin does almost the opposite of nitric oxide. It increases blood pressure and makes the blood vessels firm. Excess endothelin can also increase smooth muscle proliferation.
Medicines are available to treat each of the three imbalances, or pathways. Each medicine works on only one pathway. Many patients today are taking one PAH medication, which means they are correcting only one of the imbalances, however, studies have shown that treating more than one pathway may be a more effective treatment approach. That's why your doctor may prescribe more than one medication to improve your symptoms and delay your disease progression.
It's important that you and your doctor regularly monitor your condition and check that you're making progress against your treatment goals. The medication(s) that you start on at first may not be enough over the course of your disease. If you feel that you aren't meeting your treatment goals and that your medicine is no longer helping in the way they once did, it may be necessary to adjust or add to your treatment plan.