Blood pressure (BP), the lateral pressure exerted by blood in a unit area of blood vessel wall, is a function of cardiac output and peripheral vascular resistance. When blood volume becomes greater than the limited volume capacity of the vascular compartment, the patient develops hypertension (HTN). BP is classified as normal (< 120/80 mmHg), pre-HTN (120–139/80–89 mmHg), stage 1 HTN (140–159/90–99 mmHg), or stage 2 HTN (160/100 mmHg).24
HTN is a useful marker for CAD. The blood pressure also correlates well with obesity and sedentary lifestyle; significant use of tobacco, coffee, and alcohol; and a number of systemic diseases, e.g., dyslipidemia, diabetes mellitus (DM), thyroid dysfunction, adrenal disease, and renal insufficiency.25 Hypertension is known as the “silent killer.” High blood pressure is often asymptomatic (Box 6) until target organ damage develops (Box 7).
Drug therapy for HTN may include diuretics to reduce volume overload; electrolyte modifiers to prevent hypokalemia; and ACE inhibitors, AT II-receptor antagonists, and calcium-channel blocking agents to dilate blood vessels.26 β1-adrenergic receptor antagonists to reduce cardiac output are no longer recommended for initial therapy Many patients will require two or more agents from different drug classes to reach target BP. Key recommendations for practice are presented in Table 11.