The Phase Gate Review methodology improves project effectiveness by reviewing all stages of the project from the initial selection process through the entire process of development to the final stages of closure.
Idiopathic hypertension redirects here. For the condition of raised blood pressure within the skull, see Idiopathic intracranial hypertension. Essential hypertension (also called primary hypertension or idiopathic hypertension) is the form of hypertension that by definition has no identifiable cause.
Print Email. Learn all about ICD 9 Hypertension Essential (401) codes for hypertension 401.0, 401.1, 401.9 for malignant, benign and unspecified essential hypertension. Essential hypertension means that the cause of high blood pressure is not known. Essential hypertension is the term used to describe high blood pressure.