Other antihypertensive drug classes (angiotensin-converting enzyme inhibitors, angiotensin-receptor blockers, beta-blockers, calcium channel blockers) should be used in the presence of specific high-risk conditions (Table 9.7).
Two or more antihypertensive medications are required to achieve optimal blood pressure levels (<140/90 mm Hg or <130/80 mm Hg, respectively) for patients with diabetes or chronic kidney disease.
For patients whose blood pressure is more than 20 mm Hg above the systolic blood pressure goal or more than 10 mm Hg above the diastolic blood pressure goal, initiation of therapy using two agents, one of which will be a thiazide diuretic, should be considered.
Regardless of therapy or care, hypertension will be controlled only if patients are motivated to maintain their treatment plan. If blood pressure control is not easily achieved, if the systolic blood pressure is higher than 180 mm Hg, or if the diastolic reading is higher than 110 mm Hg, referral to an internist is recommended. Referral is indicated if secondary hypertension is suspected or evidence of end-organ damage (renal insufficiency or congestive heart failure) is present.
Measurement of Blood Pressure
An essential variable in evaluation of hypertension is how measurements are obtained and the need to standardize measurements (19). “White coat” or office hypertension (i.e., elevated just by seeing a physician) may occur in up to 30% of patients. For patients who have repeated normal measures outside of the office, it is reasonable to use ambulatory or home monitoring devices. Given the variation of accuracy and patient interpretation, it is advisable for the patient to bring their blood pressure unit into the office to calibrate it against the office-based measurements. In most patients, office readings are sufficient to adequately diagnose and monitor hypertension and eliminate problems of reliability with commercial devices and patient interpretation skills.
Blood pressure protocols for measurement should be standardized. The patient should be allowed to rest for 5 minutes in a seated position and the right arm used for measurements (for unknown reasons, the right arm has higher readings). The cuff should be applied 2 cm above the bend of the elbow and the arm positioned parallel to the ﬂoor. The cuff should be inﬂated to 30 mm Hg above the disappearance of the brachial pulse, or 220 mm Hg. The cuff should be deﬂated slowly at a rate no more than 2 mm Hg per second.
The cuff size is important, and most cuffs are marked with “normal limits” for the relative size they can accommodate. The most common clinical problem encountered is small cuffs used with obese patients, resulting in “cuff hypertension.” Phase IV Korotkoff sounds are described as the point when pulsations are mufﬂed, whereas phase V is complete disappearance. Most experts in hypertension advocate the use of phase V Korotkoff sounds, but phase IV sounds may be used in special circumstances, with the reason documented.
The use of automated devices may help eliminate discrepancies in measurements. Regardless of the method or device used, two measurements should be obtained with less than a 10 mm Hg disparity to be judged adequate. When repeated measures are performed, there should be a 2-minute rest period between readings. Blood pressure has a diurnal pattern, so determinations preferably should be done at the same time. Ambulatory monitoring is not cost-effective in all patients, but may be used to evaluate resistance to therapy, to assess “white coat” hypertension, and to determine whether syncopal episodes are related to hypotension or episodic hypertension (20).