Irish Medical Times
Friday 8 June 2012
Priscilla Lynch
Hypertension must be treated rigorously
Every year, world Hypertension Day (WHD) aims to promote public awareness of hypertension and to prevent and control this silent killer. A clinical meeting dedicated to raising awareness of hypertension and highlighting the latest research and treatment approaches was held in Dublin to coincide with WHD on May 17.
The meeting heard that hypertension is a disease that is a leading cause of mortality and morbidity worldwide, but still suffers from low awareness among the general public. However, the latest treatments and positive lifestyle changes offer hope in tackling this insidious disease.
The meeting, which was supported by A. Menarini Pharmaceuticals and Daiichi Sankyo Ireland Limited, was chaired by Prof Patrick Murray, consultant Physician at the Mater Misericordiae Hospital who welcomed the opportunity to educate fellow clinicians on the importance of controlling hypertension the keynote speakers were Dr Henry Purcell, Senior Fellow in Cardiology at the Royal Hospital’s Department of Cardiology, London and Dr. Ronan Collins, Consultant in Geriatric and Stroke Medicine, Tallaght Hospital, Dublin.
Prevalence
“Hypertension is the second biggest killer and the first cause of disability in the world, so it is key on our agenda, though we are not all that great at treating it,” Dr Purcell told the meeting.
He noted hypertension was extremely common – it affects approximately a quarter of the Irish population, and over 70 per cent of patients aged over 70 years, and is more common in males than females.
“It is a fascinating disease because it encroaches on so many processes and organs; the heart to the brain, the retina, you name it, high blood pressure is an all-embracing phenomenon.
“It is a major indicator for stroke, myocardial infaction, heart failure, chronic kidney disease, etc. For every 2 millimetre rise in systolic blood pressure, you are going to get a 7 per cent increase in heart disease and a 10 per cent increase in stroke risk.”
Discussing the causes of hypertension, Dr. Purcell said there could be a genetic link and the extent and duration were very important. Endothelial dysfunction, which is a factor in cardiovascular events, occurs in association with hypertension but can be improved by certain drugs such as angiotensin II type I receptor (ATi) blockers.
“Lowering blood pressure by 10 millimetres, systolic by 5 millimetres, reduces the risk of stroke by 35 per cent and ischaemic event by about a quarter, so it is a really important thing to do. You can almost halve the risk of having a stroke and quarter the risk of a heart attack by lowering blood pressure.”
While blood pressure increases with age, an unhealthy lifestyle is key to the development of high blood pressure.
Dr. Purcell noted NICE updated its guidelines on hypertension last year, but there still remained differences of opinion on what defined hypertension and when and how it should be treated.
“I would define stage on hypertension as being over 140/90 and for ambulatory pressure over 135/80,” Dr Purcell told the meeting.
Measuring BP
The measurement of blood pressure (BP) is an area where having the most precise equipment possible is vital as is conducting a correct exam. “Measuring blood pressure is a great art form and one of the most poorly-done measurements in all of medicine”.
Dr Purcell said it was hard to beat the original mercury sphygmometer for accuracy, which was now banned in Europe due to the mercury content. However, some of the newer widely available digital measurement devices could have variable accuracy, so he recommended using those that were validated by the British Hypertension Society.
“It is terribly important that you get your measurements right because mothers and babies could die if you don’t,” he said, citing a “scandal” in Scotland where doctors missed pre-eclampsia because the blood pressure devices they used were not validated and accurate.
The NICE guidelines also indicate that a doctor should take their time measuring a patient’s blood pressure, which is important, Dr. Purcell acknowledged.
“It’s very important if a clinic blood pressure is above 140/90 that you offer ambulatory blood pressure monitoring to confirm the diagnosis, which NICE advices, which is sensible because you could be putting the patient on drugs for life, so you want to make sure there is a disease properly there”.
Letting the patient use a home monitoring device for a short period of time was useful in this regard and also obviously addressed the issue of white coat hypertension, Dr Purcell added.
Moving on, he addressed the issue of BP dips during sleep and noted that patients whose blood pressure did not dip during the night had a higher risk of stroke.
Dr Purcell pointed out that sudden death, strokes and ischaemic events were more common in the early morning than other times of the day. “This is because blood pressures starts to rise even before you wake and ‘surges’, which may cause rupture. Your blood is also more ‘sticky’ in the morning, which means your blood pressure patients need to have drugs that work all the time, around the clock”.
Treatments
Looking at the preventable risk factors for high blood pressure, Dr Purcell said an unhealthy lifestyle was key. Obesity, lack of exercise, and high salt intake are all modifiable and have a significant impact on blood pressure, particularly weight loss.
As regards beginning pharmacological treatment, he suggested it should be commenced following diagnosis of stage one hypertension, and pointed out that there was “immense choice nowadays” for hypertensions treatment options, which a least 11 different drug types.
Dr Purcell said that a combination of two to three drugs to address the root causes of hypertension was now the optimum approach in general.
Citing a number of international studies, he said it was now clear that excellent results could be achieved using at least two antihypertensives of different classes – in one study five times better BP lowering results were achieved versus using just one class of antihypertensive.
He acknowledged that medication compliance increased with the easiest regime and said a hypertension polypill would be an ideal solution, particularly for elderly patients.
Specifically, Dr Purcell advised starting patients under the age of 55 with ACE inhibitors, while, if they were aged over 55 or of Afro-Caribbean ethnicity, he advised starting on a calcium antagonist. He said a combination of the two could then be pursued and potentially a combination of three, which was where a diuretic came in. he added that beta-blockers were now known to not be very effective in lower blood pressure.
Some patients, however, would not respond well even to a combination of three to four drugs, which was where the new procedure renal denervation by radiofrequency ablation came in, Dr Purcell concluded.
Treating the elderly
In his presentation, Dr Collins discussed the prevalence and treatment of hypertension in older patients. He reiterated the burden of hypertension internationally; there are more than 900 million in the world living with hypertension and it is the single most prevalent disease in the world, increasing the risk of a cardiovascular disease and mortality fivefold. “Furthermore, it is the most prevalent risk factor for stroke, which is our leading cause of death and disability.”
While lifestyle played a key role in the development and progression of hypertension, in older patients it was also largely attributable to stiffening of the arteries, Dr Collins explained.
Looking at US data on the prevalence of hypertension in older patients, he said it had recently been shown that 67 per cent of the US population over the age of 60 had hypertension, which would likely be replicated in Ireland in the coming years, given our current lifestyle patterns and ageing population.
Poor prognostic factors for successful hypertension control in older patients include being aged over 70, being non Caucasian, being diabetic and having chronic kidney disease, Dr Collins elaborated.
Lack of awareness
The Tallaght consultant cited local data carried out at his hospital on 200 patients of a wide age range who had already had a stroke and been educated about hypertension. Of these, 44 per cent had hypertension but only 50 per cent knew what the term hypertension meant, 56 per cent had no idea what the blood pressure target should be, while just 40 per cent agreed that lifestyle modification as important in reducing blood pressure, but “very worryingly” just 17 per cent (half of whom were on medication for hypertension) realized the importance of their medication in controlling blood pressure.
“This is a clear message that we have got to abandon using this terminology when speaking to the public. They don’t understand what ‘hypertension’ means. There is a huge education and awareness gap, particularly in working class areas.
For a disease that affects over 50 per cent of people over the age of 60, this should be common parlance. We must get this language in the public domain,’ Dr Collins maintained.
Moving on, he said many clinicians might not realize that reducing blood pressure reduced the risk of ischaemic stroke more than haemorrhagic stroke, which in his opinion was linked to atrial fibrillation as a core risk factor in stroke. One in three strokes in Ireland and the UK were caused by atrial fibrillation and it was strongly linked to hypertension, he stated.
While many clinicians were reluctant to actively treat hypertension in patients over the age of 80, Dr Collins said it was really important in order to reduce cardiac events and stroke.
“Treating patients over the age of 80 has clear benefits, even with modest reductions in hypertension.”
He also reassured clinicians that treating older patients did not increase fall risk as commonly assumed, and in fact could decrease fractures, quoting international research to back this statement up.
However, he did advise against an overly aggressively treatment approach in this cohort, saying that combining no more than two agents in an individualized approach was best, in his opinion.
Dr. Collins also stressed the benefits of a healthy lifestyle; in particular, reduced salt intake and increased consumption of fruit and vegetables as a direct treatment for hypertension, adding there was significant validated evidence of its effectiveness. He said clinicians had a duty to stress to patients that real progress in lowering their blood pressure could be achieved through lifestyle modification, rather than simply handing out a pill in the first instance.
Hypertension and other diseases
Returning to the topic of atrial fibrillation, he said treatment of hypertension in midlife with certain agents – currently ARBS – reduced the risk of atrial fibrillation.
“This is where the money is. This is where we need the large trials. We need to be preventing and delaying the onset of atrial fibrillation as we age”.
Similarly, in relation to dementia and hypertension, Dr. Collins said it had now been well established that preserving cognitive function could be helped by controlling blood pressure, and that treating hypertension early on may delay or prevent the onset of dementia as the groundwork for this disease starts to develop in the late 40s/early 50s.
“Additionally, there is a definite relationship between kidney function in older people and cognitive function and much of this may be related to hypertension as a common cornerstone of age-related disease.”
Concluding, Dr Collins concurred with Dr Purcell in advising that elderly patients are given the hypertension medications that best suit them individually and are prescribed as few medications as possible, with combination medications an obvious advantage, in order to promote better compliance.