Effect of Combination from Purple Sweet Potato (Ipomoea batatas L.) Ethanolic Extract and Ramipril Administration on Myocardial Platelet Derived Growth Factor an Expression and Myocardial Collagen Deposition in Hypertensive Rat Models Komang Surya Bhuana*, I Nyoman Wiryawan, and I Made Putra Swi Antara Abstract Objective: To determine the effect of