ICS 2012 Report – ‘‘ABPM is now mandatory for Good Clinical Practice’’

by Edel O’Connell reporting on the presentation by Professor Eoin O’Brien.

Prof Eoin O’Brien, Professor of Molecular Pharmacology, Conway Institute, University College Dublin.

Eminent Prof Eoin O’Brien told the annual ICS meeting that unless doctors fully understand the importance of ABPM in controlling hypertension the prospects for Ireland’s cardiovascular health look bleak.

Regarded as one of the world’s foremost thought leaders in hypertension research, especially in the areas of blood pressure measurement and ambulatory monitoring. Prof O’Brien said he believes it is now incumbent on all doctors who manage patients with hypertension to be able to offer ABPM to anyone suspected with the condition.

“This effectively means anyone whose office blood pressure has been found to be high. The technique should be an integral component of ongoing management,” he commented.

Currently in the Irish primary care setting, clinic blood pressure measurement control of hypertension is estimated to be achieved in only 24pc of patients, while with ABPM control this increases to 52pc.

Similarly, the RAMBLERS study found that ABPM was much more efficient at controlling hypertension.

So, Prof O’Brien asked, is clinic blood pressure measurement distorting the picture of the demographics of hypertension? And why are we doing so badly with Irish blood pressure control?

“First it is measured very badly and inaccurately but doctors also fail to recognise that blood pressure control is not just about the prescribing of medicine,” Prof O’Brien commented.

In 1988 George Pickering coined the term ‘white-coat hypertension’ to describe patients whose blood pressure is elevated in the medical environment, but not during daytime ABPM.

In another paper published in 2002, Pickering introduced the term ‘masked hypertension’ to describe what other researchers had called ‘reverse white-coat hypertension’ and ‘white-coat normotension’.

This condition denotes patients who appear to be normotensive in a doctor’s office but who have an elevated ABPM.

“Because of the proven superiority of ABPM over office blood pressure measurement in predicting outcome, such patients can be regarded as genuinely hypertensive, Prof O’Brien said.

“The clinical importance of the condition is that if blood pressure is assessed with office blood pressure measurement in a patient with a history of cardiovascular disease, e.g. a stroke or heart attack, the doctor will prescribe aspirin and a statin but deny the patient the most important treatment to prevent a cardiovascular recurrence, namely blood pressure-lowering medication, in the belief that the patient is normotensive,” he added.

The occurrence of masked hypertension in at least 10 per cent of children and adults and the presence of the reverse phenomenon of white-coat hypertension in some 20 per cent of hypertensive patients means that conventional office measurement has the potential for misdiagnosing more than 30 per cent of patients who present to doctors to have blood measure measured.

Leaving aside the many advantages of ABPM, this estimate alone, Prof O’Brien argued must make the case for ABPM being “an indispensable investigation for the diagnosis and management of hypertension in children, adolescents and adults”.

The UK National Institute for Clinical Excellence (NICE) has substituted ‘suspected hypertension’ for what other international guidelines have been labelling as ‘suspected white-coat hypertension.

“The guidelines then for the first time state unequivocally that ABPM should be offered to anyone suspected of having hypertension by virtue of having had an elevated conventional blood pressure measurement,” commented Prof O’Brien.

The guidelines state if the clinic BP is 140 ⁄90mmHg or higher, offer ABPM to confirm the diagnosis of hypertension.

“NICE has lain to rest the ghost that white-coat hypertension can be suspected, when in fact there are absolutely no clinical or other criteria that give any hint of the condition,” Prof O’Brien said.

“On the foot of these guidelines it behoves us to try and make ABPM user friendly and accessible to patients. No matter how good a technique may be, if it is not made readily accessible and financially affordable, it will simply not achieve its potential,” he added.

Toward this end, Prof O’Brien has developed the dabl software system which is capable of: providing a succinct one-page report with standardised presentation and plotting of data, with summary statistical data for day-to-day clinical use with storage of more detailed data for research; an interpretative report validated for accuracy against expert observers, so as to remove the need for a physician to report, with substantial cost benefit; a trend report of successive ABPMs showing the efficacy or otherwise of treatment during the day-time and night-time periods; and electronic transmission of data to pharmacies and other healthcare outlets to allow ready access to ABPM by patients.

Failure to acknowledge the importance of effective blood pressure management would redound on it with very negative consequences.

“With the overwhelming weight of international expertise in hypertension having voiced the opinion in many guidelines that ABPM should be offered to patients suffering from hypertension, surely the failure to provide such a facility for patients who experience the cardiovascular complications of mismanaged hypertension must soon be a cause for redress in the medico-legal forum,” he said.

“If we don’t use ABPM we are going to lose face with a patient who will have a stroke or a heart attack and will take the medical legal route because we didn’t do ABPM and we didn’t know they he had elevated nocturnal blood pressure.”

Prof O’Brien concluded by urging doctors and scientists to acknowledge the weight of opinion and no longer to resist the need to make ABPM available- not only for the diagnosis, but also for the management of all patients with hypertension.