Hypertension

Hypertension, or high blood pressure, affects over a billion people around the world. Now, ‘normal’ systolic blood pressure is defined as less than 120 mmHg, and normal diastolic pressure is less than 80 mmHg. Pre-hypertension is when systolic blood pressure is between 120 and 129 mmHg and less than 80 mmHg on the diastolic side. Stage 1 hypertension is between 130 and 139 mmHg on the systolic side, and between 80 and 89 mmHg on the diastolic side. Stage 2 hypertension is defined as anything that is 140 mmHg or higher on the Systolic side and 90 mmHg or higher on the diastolic side. Typically, both systolic and diastolic pressures tend to rise or fall together, but that’s not always the case. Sometimes, you can have systolic or diastolic hypertension, when one number is normal and the other is really high. This is referred to as isolated systolic hypertension or isolated diastolic hypertension.

There are two main types of blood pressure measurements - office blood pressure, which is taken in a clinic, emergency department, or hospital, and an out-of-office blood pressure. The out-of-office blood pressure is either a home blood pressure, which is taken by the patient at home, or an ambulatory blood pressure monitoring or ABPM, which involves 24-hour monitoring of blood pressure as the patients live their normal daily life, and while they sleep, to see if the blood pressure falls at night compared to during the day. It uses a small digital blood pressure machine that is attached to a belt around the body and it’s connected to a cuff around the upper arm. Ambulatory blood pressure monitoring is the best way to diagnose hypertension, but it’s not always feasible, so it’s usually done when office and home blood pressure measurements are really discordant from one another.

Now, the first step for an office blood pressure, is to make sure that the patient has rested for at least five minutes and is positioned properly - sitting with their arms and back supported, and their feet flat on the floor. And the measurement should be repeated at least twice. Most of the time, blood pressure is taken in the brachial artery in the upper arm, because if the pressure is high there, it’s probably high throughout the arteries. And keep in mind that just being in the office can cause blood pressure to change. In white coat hypertension - a person’s blood pressure rises, and in masked hypertension - a person’s blood pressure falls. So, the diagnosis of hypertension should be done by looking at both office and out-of-office blood pressure measurements.

The second step is taking the patient’s history and physical examination. Now, there are two main types of hypertension - primary or essential hypertension has no clearly identifiable underlying reason, and secondary hypertension, which does have a specific, identifiable underlying condition. Primary hypertension is way more common, and it generally isn’t accompanied by symptoms. It’s sometimes called a “silent killer”, because over time, pressure in the arteries silently creeps up, and causes blood vessel damage which is a risk factor for serious problems, like myocardial infarctions, aneurysms, and strokes. Risk factors for primary hypertension include: old age, obesity, family history, a salt-heavy diet, a sedentary lifestyle, heavy alcohol consumption, smoking, and race - for example, people of african descent are more likely to develop hypertension. And some of these risk factors can be improved with lifestyle changes that can help reduce hypertension. Now, secondary hypertension often is accompanied by a variety of symptoms associated with the underlying cause. In general, the younger the patient, the more likely it’s secondary hypertension. For example, anything that limits the renal blood flow can cause hypertension, like fibromuscular dysplasia, which generally affects young women, but also atherosclerosis in older patients. Other examples include obstructive sleep apnea, atherosclerosis, vasculitis, or aortic dissection, as well as pheochromocytoma, Cushing’s syndrome, and other endocrine disorders.

It’s also important to identify signs of end-organ damage, and whether the patient takes any medications or exogenous substances that can worsen hypertension, sympathomimetic agents like decongestants or even cocaine, cyclosporine or tacrolimus, sodium-containing antacids, stimulants like amphetamines, atypical antipsychotics like clozapine, antidepressants, oral contraceptives, erythropoietin, and even NSAIDS and liquorice - that delicious chewy black candy! A basal metabolic panel and electrocardiography should be performed to screen for secondary forms of hypertension.

Management for hypertension is mainly based on the hypertension stage, risk of developing cardiovascular events and organ damage, as well as taking into account any concomitant diseases, such as diabetes or chronic kidney disease. Lifestyle changes are crucial for all patients, especially in the long term, and include things like quitting smoking, drinking alcohol in moderation, maintaining a healthy weight, reducing dietary sodium, and staying physically active. Not all patients with hypertension need antihypertensive drug therapy. In fact, medication is generally suggested for only patients with out-of-office daytime blood pressures higher than 135mm Hg systolic or higher than 85 mmHg diastolic, or an average office blood pressure higher than 140/90 mmHg if out-of-office readings aren’t available. It’s also recommended for patients with an out-of-office blood pressure higher than 130 mmHg systolic or 80 mmHg diastolic or, if out-of-office readings are unavailable, or an average office blood pressure higher than 130 mmHg systolic or 80 mmHg diastolic who also have other features. Specifically they need to have at least one of the following: cardiovascular disease, type 2 diabetes mellitus, chronic kidney disease, be over 65 years old, or have an elevated risk of coronary artery disease. On the flip side, it’s generally recommended not to give antihypertensive medication to patients with stage 1 hypertension and are either over age 75 years old or have no organ damage.

There are four main classes of medications that are used to treat hypertension, ACE inhibitors, Angiotensin Receptor Blockers or ARBs, thiazide diuretics, and long-acting calcium channel blockers like dihydropyridine. There is a lot of variability in terms of how individuals respond to different medications, so it’s important to follow up to see how the medications are working. Usually, therapy begins by choosing one medication. Broadly speaking, ACE inhibitors are started in patients at high risk for coronary artery disease, including those with a prior STEMI, heart failure, asymptomatic left ventricular dysfunction, diabetes, and chronic kidney disease. A common side effect of ACE inhibitors is chronic cough, so ARBs are often started in patients who don’t tolerate ACE inhibitors, mostly because of cough. Thiazide diuretics and calcium channel blockers show very similar efficacy to ACE inhibitors, and they’re first line therapy in patients of african descent. But diuretics have a lot of metabolic effects, so they can’t be given to patients with high blood glucose and cholesterol levels.