What is Resistant Hypertension (RH)
As it name implies Resistant Hypertension is an intractable form of High Blood Pressure because it is so hard to treat. It is the kind of hypertension which will not respond to the types of intervention approaches which can usually be applied successfully to help manage a high blood pressure condition. This includes both medical and non-medical (lifestyle changes and natural) treatment approaches.
The Journal of the American Board of Family Medicine describes it thus:
“Resistant hypertension (RH) is defined as blood pressure above a goal despite adherence to at least 3 optimally dosed antihypertensive medications of different classes, one of which is a diuretic”
Naturally, being diagnosed with such a form of Hypertension is both upsetting and anxiety-provoking for the patient and a source of frustration for the consulting physician.
What causes Resistant Hypertension (RH)?
WHEN it is possible to treat most cases of pre-hypertension, or full blown hypertension, with either natural approaches using lifestyle changes such as:
- Healthy Diet
- Regular Exercise and Activity
- Stress Management and Relaxation Techniques
- Holistic Treatments - Yoga, Meditation, Deep Breathing
- Blood Pressure Supplements
if necessary, by using one or two prescription antihypertensive medications…
THEN the 64,000 dollar question becomes:
Why in fact does the blood pressure condition remain so resistant to any form of treatment in about 10% of cases?
This is indeed a CONUNDRUM!!
Interestingly enough some causes of Resistant Hypertension might be as simple as “White Coat” RH when the patient’s BP reading at the Doctor’s Office is consistently high, even although at home their BP is being well-managed. This of course must be eliminated as a possible cause and is easily remedied by using self-monitoring with an In-home BP cuff, or an Ambulatory BP device over a 24 hour period.
Then there is the human factor; in the case of the patient who is not following the prescribed drug regimen to the tee and, due to possible unpleasant side effects of the medications, is missing occasional doses. And with older patients, who must take multiple medications more than once a day, forgetfulness can play a role, too!
This can be remedied by change of prescription, or medication, to alleviate side effects and by finding ways to prevent missed doses from occuring, e.g. arranging for a relative or friend to help out with daily drug-taking.
By far the most likely reason for RH which Doctors will consider is related to possible secondary causes (contributing factors) of Resistant Hypertension. The most common secondary causes are (as listed by the AHA - American Heart Association):
- Abnormalities in the hormones that control blood pressure. (Aldosteronism - excessive hormone production in Adrenal Glands)
- The accumulation of artery-clogging plaque in blood vessels that nourish the kidneys, a condition called renal artery stenosis. This is most typical in older people.
- Sleep problems, such as the breath-holding type of snoring known as obstructive sleep apnea.
- Obesity or heavy intake of alcohol or other substances that can interfere with blood pressure.
Once the secondary cause has been identified there is a much better chance that the doctor, or specialist, will then be able to come up with an effective treatment plan to deal with the RH.
For example, one very promising development is the discovery that patients, whose RH is caused by their adrenal glands over-producing the hormone Aldosterone, are much more susceptible to sodium retention.
In a recent PATHWAY study on RH from Queen Mary University, London, England it was revealed that the use of the medication Spironolactone - a diuretic medication which has been around for over 50 years, but rarely used in the treatment of hypertension - was found to be far more effective than most other anti-hypertensive medications in reducing blood pressure in patients with intractable hypertension.
An even older second diuretic medication - Amiloride - also had beneficial effects in cases where the spironolactone wasn’t well tolerated.
According to Dr Morris Brown, chief investigator for the original study:
“The discovery of salt overload as the underlying cause has enabled us to target the hormone which drives this, and to treat or cure most of the patients.”
This study was further investigated by Dr Bryan Williams, Chair of Medicine at University College London, UK. His findings showed that:
“Both spironolactone and amiloride block the effects of aldosterone — which is probably why they are especially effective in RH”
For those people dealing with drug resistant hypertension this discovery may make it possible for them to be treated in the future with a smaller number of more effective medications. This is indeed very encouraging news!!
There is some innovative and non-pharmacological research going on which is starting to show some promise in dealing with this issue of Resistant Hypertension.
One group in looking at using electrical stimulation of the carotid sinus baroreceptor to bring about a reduction in drug resistant high blood pressure.
Results from an initial study showed that the effect of using a small implantable baroreceptor stimulator over a 3 month period led to an average decrease in systolic BP of 21 mmHg and a diastolic BP decrease of 12mmHg. More exciting is the fact that this decrease improved to systolic 33mmHg and diastolic 22mmHg when a follow-up was conducted 2 years later.
The intensity of blood pressure drug treatment wasn’t changed, suggesting that the BP changes were related to the implanted device rather than to the medications.
Another non-pharmacological approach was conducted using Catheter-based radio frequency renal denervation.
The method used here was to interrupt the renal sympathetic nervous system by introducing a radio-frequency catheter to the renal arteries in order to perform circumferential radio-frequency removal. This subsequently allowed for better blood pressure control since an overactive sympathetic nervous system has been shown to be one cause of hypertension.
To date this technique has been used primarily in Europe, and is now being tested in studies in the United States. So far results have been encouraging but further trials are deemed necessary before such a procedure will be ready for implementation as a clinical practice.
About one in ten people presenting with Hypertension are actually dealing with the more intractable form of the condition and, as such, are already taking a cocktail of 3 different medications to help treat the problem.
I am encouraged to see that there is light at the end of the tunnel when it comes to less pharmacologically-dependent treatment options which will be available in the future.
I hope that advances in the area of less intrusive technology, such as the two techniques I describe above, may make it possible for these hard-to-treat patients to be able to at least reduce the need to take so many prescription medications.
And ultimately perhaps the most intractable of hypertension sufferers may then find that they can have more success using some of the more natural and safer approaches to managing their blood pressure levels.
That would be really wonderful!!
If you would like join the discussion on this topic please let me know what you think in the comments section below. 🙂