MADRID — European and American hypertension specialists appear to be mending their rift over the issue of “prehypertension,” and moving toward consensus on the importance of treating the earliest stages of the hypertensive disease process.
Leaders of the European Society of Hypertension (ESH) and the American Society of Hypertension (ASH) held a first-ever joint meeting during the European society's 16th Annual European Meeting on Hypertension. Despite past differences regarding prehypertension, views on both sides of the Atlantic now show far more convergence than divergence.
The concept of prehypertension, and the position that some high-risk people with blood pressures as low as 120/80 mm Hg should be treated with antihypertensive drugs, drew considerable criticism, especially from European cardiologists, when it was first articulated in the 2003 Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC 7) guidelines. Critics on both sides of the ocean argued that JNC was doing the bidding of pharmaceutical companies by lowering the treatment threshold in a way that would suddenly render as many as 50 million more people eligible for drug therapy.
Dr. Thomas D. Giles, immediate past president of ASH, who represented the Americans in the joint meeting, defended the underlying intention of the recommendations. “JNC was calling attention to the fact that just because the blood pressure isn't over 140/90 doesn't mean there's no disease process going on.” Essentially, JNC took the 120/80 cut-point, considered “optimal” in the previous guidelines, and made it the new “normal,” with the new “optimal” being under the 120/80 mark.
Over the last 3 years, a number of studies and metaanalyses have shed light on the subject, dispelling much of the criticism but also tempering the enthusiasm of those who would treat anyone with systolic pressure over 120 mm Hg.
The Trial of Preventing Hypertension (TROPHY) showed that treatment of high-risk but normotensive patients could keep them from going into the hypertension range (Am. J. Hypertens. 2005;18:980–5). Dr. Giles pointed out that although these patients were considered normotensive under current guidelines, many of them had multiple risk factors for cardiovascular disease.
“These were not normal people. They were actually sick, and the study showed that if you give them an ARB [angiotensin receptor blocker] and get a 10-mm reduction in systolic [blood pressure], you can prevent emergence of frank hypertension. I would not want to be in the placebo group of the TROPHY study,” he said.
In aggregate, available data support the notion that the hypertensive and cardiovascular disease process begins well before blood pressure increases, and that early intervention can reduce cardiovascular risk. However, the emerging view obliterates the idea of simple blood pressure cut-points and supports the European view that blood pressure itself is only one of many variables that must be considered in a global clinical assessment of a person's cardiovascular risk.
The very same data set that gave rise to the original prehypertension concept also challenges the idea of simple clinical cut-points. JNC developed the prehypertension idea after looking at the data of Lewington and colleagues (Lancet 2002;360:1903–13), which showed that cardiovascular risk begins to rise at pressures as low as 115/75. For each 20/10 mm Hg rise in pressure, there is a doubling of cardiovascular risk. But these same data obliterate simple thresholds. “There really is no cut-point, no threshold. There's only a continuum of risk that begins after 115/75.”
The point, said Dr. Giles, is that “you cannot treat blood pressure isolated from the rest of the patient. … New definitions of hypertension should not be based on rigid numeric cut-offs, but rather on assessment of the overall state of the cardiovascular system.”
If Dr. Giles' comments seem to have a decidedly European accent, Dr. Giuseppe Mancia, executive officer of the Scientific Council for ESH, said European views are starting to move to an American beat. “There are a lot of high-risk people who have early signs of organ damage, and they need treatment regardless of the blood pressure numbers,” he said.
Dr. Peter Sleight, of the department of cardiovascular medicine at John Radcliffe Hospital, Oxford, England, said that one of the main virtues of JNC's prehypertension idea is that it called attention to the fact that the majority of strokes occur in people who would have been considered normotensive under previous guidelines. “The whole game in stroke prevention is in lowering blood pressure. A systolic of 135 carries lower risk than a systolic of 145,” said Dr. Sleight.
ESH is in the process of revising its therapeutic guidelines, which were last revised in 2003, and the new edition is expected sometime next year. Although it is too soon to know exactly what they will say, Dr. Mancia predicted they will likely move European practice standards closer to the early-intervention predilection of the Americans.