New Orleans, LA—Resistant hypertension can be challenging to treat, but there are strategies and steps primary care physicians (PCPs) can take to help patients achieve blood pressure (BP) control. These strategies were discussed in a recent session at Cardiometabolic Risk Summit Spring 2015 led by Michael J. Bloch, MD, FACP, FNLA, FASH, FVM, associate professor, department of internal medicine, University of Nevada School of Medicine.
According to the Eighth Joint National Committee, “resistant hypertension” is defined as BP that remains over 140/90 mm Hg in patients who are adhering to an adequate and appropriate regimen of 3 drugs. Using National Health Awareness Nutrition Education Survey data from 2005 to 2008, its estimated that 14% of those with hypertension have apparent treatment resistance.
Dr Bloch said the first step in treating patients with resistant hypertension is identifying those patients who have a resistant form of hypertension.
Once treatment resistance has been confirmed, Dr Bloch said the next step is to rule out pseudo-resistance. There are a number of common causes of pseudo-resistance, including poor medication adherence to prescribed medications, using an improper technique to measure BP, or white coat effect.
“Identifying these patients is crucial to making sure that we are not needlessly increasing pharmacological therapy,” Dr Bloch said.
When to Suspect Pseudo-Resistance
He mentioned PCPs should suspect pseudo-resistance when the patient has marked hypertension without target organ damage, or displays symptoms consistent with hypotension after BP therapy, but does not see a significant decrease in BP.
The Spanish Ambulatory Blood Pressure Monitoring Registry of 8295 patients thought to have resistant hypertension found that while 62.5% of patients did have true resistance, an additional 37.5% were only resistant due to white coat effect.
Using different BP measurement settings can be one way to get a clearer picture of a patient’s true BP, but Dr Bloch stressed this strategy comes with both pros and cons. The advantages of taking BP measurements in a clinic setting are that it is convenient and is associated with clinical trial outcomes data. However, there is risk of white coat effect and masked hypertension.
Home measurement can be inexpensive and empowers patients to take a greater role in their care, but it can cause anxiety for patients, measurement devices can vary, and it may produce little outcomes data.
Ambulatory BP monitoring devices give clinicians a large number of measurements, including those taken while the patient sleeps. But it is also the most expensive measurement option and inconvenient for a patient to do repeatedly.
Lifestyle Factors and Secondary Causes
The next treatment strategy for resistant hypertension patients is to identify and reverse contributing lifestyle factors. “Patients with resistant hypertension are often quite salt sensitive,” stated Dr Bloch. “Obesity, sedentary lifestyle, excessive alcohol, and illicit drug use are also important.”
Once lifestyle factors have been addressed, Dr Bloch mentioned patients should also discontinue or minimize interfering substances such as nonsterodial anti-inflammatory drugs, alcohol, oral contraceptives, decongestants, stimulants, and certain herbal compounds.
Other drugs that can interfere with BP therapy are corticosteriods, anti-depressants, cyclosporine, erythropoietin, and illicit drugs.
Next, PCPs should screen for a secondary cause of hypertension. Common contributing causes are obstructive sleep apnea, renal parenchymal disease, primary aldosteronism, and renal artery stenosis. Less common contributing causes include Cushing’s disease, pheochromocytoma, aortic coarctation, hyperparathyroidism, and intracranial tumor. “The prevalence of secondary hypertension is higher in patients with resistant hypertension,” said Dr Bloch. “Identification of secondary causes of hypertension can help guide therapy, either pharmacological or otherwise, to help improve BP control.”
Dr Bloch said once secondary causes of hypertension have been considered, PCPs should rationalize or intensify pharmacological treatment.
Initial Treatment Strategies
For initial treatment of patients having difficulty controlling their hypertension, Dr Bloch recommended a combination of a renin-angiotensin system blocker, such as angiotensin-converting-enzyme-inhibitor or angiotensin II receptor blocker, along with a thiazide type diuretic and calcium channel blocker.
If additional steps are necessary, PCPs may want to consider loop diuretics for patients with an underlying creatinine clearance of <30 mL/min. Another way to maximize diuretic therapy is to add a mineralocorticoid receptor antagonist, such as spironolactone, eplerenone, or amiloride.
Determining the best add-on therapy for patients is unfortunately more of an art than a science, said Dr Bloch, because few clinical trials exist to guide decisions when treating resistant hypertension.
“Certainly, spironolactone is a good choice for many patients and is supported by some degree of clinical trial evidence, but does require monitoring of renal function and electrolytes,” he said.
“In my experience, peripheral alpha blockers, although associated with adverse effects in some patients, are also a good option for many patients. Other drug classes may have a role in individual patients as well,” he added.
If PCPs go through all these steps and patients are still struggling to control BP, Dr Bloch said the final step is to refer the patient on to a clinical hypertension specialist.
He concluded by saying that more research needs to be done to answer some unanswered questions about which add-on therapies may be most beneficial, and what new emerging or potential treatment options for truly resistant hypertension could play a valuable role in the years ahead.—Jill Sederstrom