High Blood Pressure or Hypertension is one of the main causes of stroke, heart disease, heart attack and kidney disease. Traditionally physicians use diet and lifestyles change and medications to control patient's blood pressure. There are however, some patients whose blood pressures are difficult to control and their blood pressure remains elevated despite multiple medications. When blood pressure remains above goal (greater then 140/90 or greater then 130/80 mmHg in patients with diabetes or kidney disease) despite 3 or more blood pressure medications, the investigators call it "Resistant Hypertension".