Pre - hypertension : Concepts and management

Subjects with “pre-hypertension”—adults with blood pressure (BP) ranging from 120–139 mmHg systolic and/or 80–89 mmHg diastolic—are at increased risk of future hypertension and cardiovascular disease (CVD) including myocardial infarction, stroke, heart failure, and cardiovascular death. Adoption of healthier lifestyles in individuals with BP in this range might lower their BP, delay or prevent hypertension, and reduce the risk of CVD. On the other hand, it might increase public anxiety and lead to unnecessary physician visits. Prehypertension should be differentiated from labile (or borderline) hypertension, a term used for subjects who are demonstrated to have paroxysmal hypertension. While majority of subjects found to have pre-hypertension will eventually develop hypertension by the age of 60, about one fifths continue to stay pre-hypertensive or exhibit a fall in BP in optimal range. There is no simple way to predict which prehypertensive subjects will develop sustained hypertension though lower body-mass index (BMI) and higher physicalactivity may be associated with a lower risk. Coronary calcium may be a key predictor of future cardiovascular events in patients with pre-hypertension, particularly women. Though no large randomized studies have shown that therapeutic lifestyle changes will reduce the risk of incident hypertension or avert stroke in patients with prehypertension, there seems no controversy about the desirability of healthy lifestyles in pre-hypertension. What is not known is whether drug treatment is warranted in this range of BP and the ongoing trials will attempt to answer this question. But even if these trials are able to demonstrate that anti-hypertensive drug therapy in pre-hypertension will reduce progression to hypertension and its complications, the question of cost-effective of pharmacotherapy will remain unanswered. The main stimulus for introducing pre-hypertension as a category of BP was Prospective Studies Collaboration (2002), a meta-analysis of 61 prospective epidemiological studies incorporating ~1 million subjects which found that in the middle aged and the elderly, each increment of 20 mmHg in SBP or 10 mmHg in diastolic BP (DBP) doubles the risk of coronary artery disease and stroke mortality, 3 starting at 115/75 mmHg. This was consistent with Framingham Heart Study in which subjects with BP in prehypertensive range were at increased risk of hypertension during 4 years follow-up, particularly in the elderly (Table 4 1). In the same study, pre-hypertension was associated with an increase in the risk of cardiovascular disease 5 including myocardial infarction (MI), but not stroke. In Women Health Initiative (WHI), pre-hypertension was associated with MI (hazard ratio, HR 1.76, 95% CI 1.402.22) as well as stroke (HR 1.93, 95% CI 1.49-2.50), heart failure (HR 1.36, 95% CI 1.05-1.77), and CV death (HR 6 1.58, 95% CI 1.12-2.21). The purpose of introducing pre-hypertension as a category was to increase awareness amongst public and health professionals that adoption of healthier lifestyles in individuals with BP in this range might lower their BP, 1 delay or prevent hypertension, and reduce the risk of CVD. Criticism was soon raised against this term as it might increase public anxiety and lead to unnecessary physician visits for millions. Yet, it was recognized that BP in this range did increase the risk of progression to hypertension and future CVD, particularly when the baseline BP was 130–139/85–89 mmHg and in many such subjects, high global cardiovascular risk necessitated pharmacological intervention. Pre-hypertension should be differentiated from the so called labile (or borderline) hypertension, a term often used for subjects who are demonstrated to have paroxysmal hypertension. Unlike pre-hypertension, where BP is consistently below hypertensive range, BP in labile hypertension is intermittently >140 mmHg systolic and/or >90 mmHg diastolic. A common cause of labile hypertension is panic disorder. At other times, it is a precursor of more sustained hypertension when it may be accompanied by a hyper-adrenergic state manifesting as anxiety, sweating, palpitations, sinus tachycardia, and elevation of systolic BP. Rarely, labile hypertension is due to pheochromocytoma though hypertension in this condition is very often sustained. Patients with labile hypertension may benefit from pharmacological intervention, particularly when markers of early target organ damage, such as left ventricular (LV) hypertrophy, increase in LV end diastolic diameter or LV mass index, carotid intimal medial thickness or microalbuminuria are