Hypertension increases the risk of heart attack and stroke and represents a public-health scourge of gargantuan proportions. It is inextricably linked to a gamut of other diseases, representing various organ systems. Here’s a look at four such relationships.

Ischaemic stroke

One major repercussion of chronic hypertension involves cerebral arteries/arterioles, with increases in cerebrovascular resistance and brain hypoperfusion evident.

Of note, pial vessels develop smaller lumens and increased tone in the long-term secondary to hypertension. Furthermore, hypertension increases the severity/extent of hypoperfusion and reduces the amount of penumbral tissue during the ischaemic stroke. (The penumbra is the hypoperfused tissue girding the ischaemic core, to which blood flow is too low to sustain electric activity but high enough to maintain ion channels.)

Chronic hypertension interferes with cerebral circulation via structural remodelling, which entails hypertrophy and inward remodelling of cerebral arterioles. Higher levels of angiotensin II in hypertension mediates inward remodelling in cerebral arteries and arterioles, which helps explain the clinical utility of angiotensin-converting (ACE) inhibitors. Intriguingly, hypertension itself doesn’t trigger this remodelling.

Depression

Hypertension and depression combine in sinister ways and can increase the risk for all-cause mortality. In a study published in the Scandinavian Journal of Primary Care, investigators found that symptoms of depression are common in hypertensive patients without comorbidities who know they have hypertension. In other words, it appears that a person merely knowing that they have hypertension can play a role in depression. 

The authors wrote:

“Many modifiable, lifestyle-associated factors may contribute to the association of hypertension and depressive symptoms. Clinicians should consider depressive symptoms when treating hypertensive subjects and find ways to enhance their psychological well-being in order to promote a favourable lifestyle and control of hypertension.”

HIV

Hypertension is a burgeoning problem in those with HIV, with patients on antiretroviral therapy (ART) exhibiting a higher prevalence of the disease. According to global meta-analysis data cited by the authors of an article published in Hypertension, 35% of HIV-infected adults taking ART have hypertension compared with 30% of adults without HIV.

Moreover, in adults aged 50 years or more, more than 50% have hypertension. HIV also increases the risk of other types of heart disease and all-cause mortality. The authors wrote those novel pathophysiological mechanisms in individuals with HIV and hypertension include:

1. Microbial translocation
2. Chronic inflammation
3. Immune suppression/reconstitution
4. Viral tropism
5. Lipodystrophy
6. Adipokines
7. HIV-related renal disease

Obstructive sleep apnoea

In the general population, the presence of obstructive sleep apnoea (OSA) ranges between 4% and 7%, whereas hypertension affects between 30% and 40% of people. In those with OSA, about half also have hypertension, according to the Sleep Foundation.

In healthy people, blood pressure drops by between 10% and 20% at night, which is referred to as 'blood pressure dipping.' People with severe OSA drop by less than 10% during sleep. This non-dipping pattern increases the risk of heart disease.

Moreover, those with OSA have higher blood pressure when they wake up in the morning. This morning surge may also increase the chance of heart disease. OSA can also increase daytime blood pressure levels, depending on severity.

The sleep disruption of OSA prompts the adrenal glands to release catecholamines, including epinephrine and dopamine, which activate the sympathetic system and elevate blood pressure.

This story is contributed by Naveed Saleh and is a part of our Global Content Initiative, where we feature selected stories from our Global network which we believe would be most useful and informative to our doctor members.