Hypertension is the most prevalent treatable risk factor for stroke and other vascular events in this country and even moderate elevations of blood pressure (BP) lead to shortened life expectancy. The condition is most commonly encountered in the older adult, a section of society whose numbers are predicted to increase, where its management can be also more challenging. 

The number of medications at our disposal that lower BP has increased in recent times, as have the complexity and expectations of our patients. 

While dietary and lifestyle changes can improve BP control and decrease the risk of associated health complications, for the majority, drug treatment is necessary. 

BP therapy

The decision to commence BP therapy in primary care for what is in the most part an asymptomatic condition can be difficult. We need to adequately resource primary care to allow for the diagnosis and management of hypertension. Until this occurs we will not realise the reductions in stroke events and reduced financial and social burden on the health service. 

In the UK, the Quality and Outcomes Framework is an attempt to resource and reward good practice across certain clinical areas including hypertension in primary care. 

While it does concentrate solely on clinic-measured blood pressures and uses higher BP targets, it is at least recognition that extra funding is required. Locally, we have attempted to set stroke and hypertension networks using shared care models that allow easy referrals and virtual consultations on high risk patients. Hopefully this will support increased ABP usage in the community.

Case one

A 47-year-old male has been referred by his GP for difficult-to-treat hypertension ongoing for the past five years. He was maintained on a calcium antagonist, having previously developed abnormal electrolytes on a diuretic. 

These abnormalities, an elevated serum sodium and low potassium had persisted despite trials of other medications and prompted the referral. He had a stressful job, was overweight, did not take supplemental salt, was a non-smoker and drank about 30 units of alcohol a week. 

General examination was normal, including fundoscopy. He had evidence of proteinuria and LVH on his ECG. Ambulatory blood pressure (ABP) recording confirmed moderate hypertension.

Discussion 

While the prevalence of secondary hypertension is small, it is reasonable to screen those where there is an index of suspicion. It would be my practice to screen all younger patients with hypertension confirmed on ABP. Some routine investigations are reasonable to perform on all patients presenting with an elevated BP. Much of these, for example fasting lipid profile and glucose, are important for risk stratification of the patient using the Framingham score charts. In this case, the abnormal electrolytes suggest a possible excess aldosterone production by the adrenal glands. 

Subsequent serum renin and aldosterone levels showed an abnormally low ratio and follow-up MRI of his adrenals confirmed a solitary adrenal adenoma. The majority of primary aldosteronism is due to bilateral adrenal hyperplasia with adenomas as in this case, accounting for only about 5% of cases. He proceeded to laparoscopic surgery and had the lesion removed. While his electrolytes improved he continues to attend for treatment of his hypertension.

Case two

A 67-year-old gentleman with long-standing hypertension was referred by his GP to the unit for urgent review. While his blood pressure, based on home recordings, was never ideally controlled, over the past three days it had become more erratic. 

This had been preceded by what he described as a pre-syncopal episode while shaving. He had a persistent mild
headache and found that he had to concentrate more on walking in a straight line. He was right-handed, very hypertensive and on examination had some fine motor deficits on the left side. He had a mild dysarthria. 

Discussion

This brief history suggests the acute onset of focal neurological deficit. Subsequent urgent CT brain confirmed a small, deep, right-sided intracerebral haemorrhage (ICH) with some surrounding oedema. Few conditions are as closely intertwined with hypertension as ICH. 

While the initial management may involve discontinuing medications such as antiplatelet agents and treating any complications of the stroke that may have arisen, the vast majority of the acute and chronic care relates to close BP control. In the acute phase there is good evidence to suggest that aggressively lowering the blood pressure reduces the risk of haemorrhage enlargement while post-discharge, all we can offer the patient is renewed efforts towards tight blood pressure control. ICH accounts for about 15% of all strokes. 

While conditions such as amyloid angiopathy and vascular abnormalities such as artero-venous malformations may account for more peripherally based bleeds there is still a potent interaction with background hypertension. When one considers that hypertension is also the most important risk for ischaemic stroke it is important that we put well-resourced structures in place to tackle the burden in primary care. The financial burden of stroke to the State is considerable and likely to increase.

Case three

A 33-year-old male is referred to the hypertension clinic having been sent in by his GP to casualty the previous day with a mild frontal headache and elevated blood pressure readings, especially diastolic. He has no previous history of hypertension, is a smoker with elevated alcohol intake and has recently been made unemployed. 

He does not exercise regularly, is mildly overweight and admits to having a poor diet. He initially attended his GP to get a repeat prescription for inhaler and mentioned the headache. Routine investigations in casualty were normal. He was observed for about 12 hours after the administration of a calcium antagonist and let home with follow-up at our clinic.

Discussion

The above represents a typical referral to our clinic. When we encounter somebody with elevated BP, especially the younger adult, our thoughts turn to cases one and two as outlined above. 

By that I mean, is there a reason to suspect secondary hypertension or has there been an acute event bringing about the elevated blood pressure. In the vast majority of presentations, neither is the case. The above patient had no evidence of target organ damage. 

He had a normal ambulatory recording on treatment and after some lifestyle modifications had a further normal recording off all treatments. He was discharged and advised to have periodic monitoring of his BP.

Blood pressure measurement

Underlying blood pressure is widely considered to be of primary importance in the cause of vascular disease, and hence in the diagnosis and treatment of hypertension, and this concept is reflected in all major clinical guidelines. 

In some papers our group published in the Lancet last year, we showed that while mean blood pressure is clearly important, other factors related to the medium-term changes in blood pressure were also significant and thus a potential target of therapy. 

Clinic measurements

Much of the difficulty in managing hypertension relates to the persistent use of clinic measurements to decide upon treatment. At presentation, all patients should have an ambulatory monitoring performed. It allows for the detection of white coat hypertension, the prevalence of which may be as high a 30% in some populations. It also gives an accurate analysis of mean pressure and allows for the detection of increased variability and other abnormalities. 

One further point is that in those hypertensive patients with controlled daytime blood pressure with elevated nocturnal readings some consideration should be given to changing the timing of some of the medications to give better 24-hour control.

Therapeutics 

The challenge here is the fact that the majority of our patients need more than one blood pressure drug to achieve control. It is likely that the use of combination therapy, the availability of which has thankfully increased in recent years, will be essential in the management of our patients.

These combinations, available in a range of dosing to allow for controlled up-titration, will offset any negative effect on issues such as blood pressure variability and bring a potent reduction in blood pressure.

The future 

There has been a number of interesting publications in the area of hypertension over the last year. A UK-based group showed by using telemonitoring of blood pressure and agreed care pathways how BP control could be improved upon with patient participation. 

The management of resistant hypertension may be improved by the introduction of renal sympathetic denervation. 

In a series of recent publications, this safe, catheter-based procedure, where the sympathetic nerves that lie in the wall of the renal artery are cauterised, showed an impressive persistent reduction in blood pressure in these difficult-to-treat patients. This may provide a further treatment choice in patients where we have exhausted our choice of medications.