Blood pressure control after a stroke

The burden of stroke and cardiovascular disease (CVD) continues to rise across the world [1–3]. The Global Burden of Disease study reports that by 2010, high blood pressure had become the leading risk factor globally for both deaths and disability (disability-adjusted life years), and that ischaemic heart disease and stroke were first and second, respectively, among causes of death across the world [1–3]. Between them, ischaemic heart disease and stroke accounted for 12.9 million deaths, or one in four deaths worldwide, and the majority of these deaths were attributable to high blood pressure. The latest publication from the Global Burden of Disease study drills down on the drivers of these increases, both globally and in 21 regions covering 188 countries, and reports that two dominant factors are responsible, the growth of populations and the ageing of populations that are seen across the globe [4]. These two factors overcome an opposing trend from decreases in age-specific death rates, in almost all regions of the world. However, there are two regions out of the 21, where the gains in age-specific cardiovascular health were sufficient to offset these two demographic factors, and result in an overall decrease in deaths due to CVD – Western Europe and Central Europe, where the total number of CVD deaths fell by 13 and 5%, respectively [4]. This issue of the Journal of Hypertension presents a very relevant article from Central Europe, reflecting on our performance in controlling blood pressure in both stroke survivors and in a population sample [5]. Specifically, Cifkova et al.[5] report on 424 survivors of ischaemic stroke, treated in two university hospitals in the Czech Republic, and 414 population controls selected from a 1% random sample of the Czech post-MONICA study, both aged 66 years on average at the time of examination. Confirming the dominant importance of high blood pressure, the authors report that they found hypertension in 92% of stroke survivors and 72% of population controls. Although use of blood pressure-lowering drugs was common in both the groups, 80% in poststroke survivors and 57% in the controls, effective blood pressure control, defined as blood pressure 140/90 mmHg or less, was found only in 43% of stroke survivors and 44% of population controls [5]. The significant predictors of good control were use of angiotensin-converting enzyme inhibitors, number of blood pressure-lowering drugs used, female sex and university education. Similarly, statins were taken by 60% of stroke survivors but a low-density lipoprotein cholesterol of less than 2.5 mmol/l was achieved in less than half. On the other hand, about three-quarters of survivors did take antiplatelet agents, including aspirin. Another disappointment was the fact that about one-third of the survivor group continued to smoke and 40% were obese [5]. The authors conclude that these findings reflect poor implementation of guideline recommendations by clinicians, particularly general practitioners who treat the majority of stroke survivors. They also point to the paucity of evidence regarding target blood pressures in elderly patients. Overall, the study is timely, well conceived and well conducted, with careful documentation of stroke survivors treated in stroke units in two major university hospitals in the Czech Republic – the first such report from a country in Central Europe. Although the sample size is small, the study was rigorously analyzed and the population control group appropriate for the purpose. The study also resonates well with many other major studies reporting on poor control of blood pressure and other cardiovascular risks factors in a variety of populations [6–12]. For example, EuroAspire has reported that only 40% of patients with coronary heart disease in eight European countries, including the Czech Republic, had blood pressure 140/90 mmHg or less [9,12]. Even more disappointing, the Prospective Urban Rural Epidemiology study of hypertension treatment and control in 143 830 people from 17 high, middle and low-income countries reported that over 40% of the population had hypertension, defined as blood pressure at least 140/90 mmHg, but that less than half were aware of this, and less than 15% of those treated were controlled, with blood pressure less than 140/90 mmHg [13]. Furthermore, less than 15% of those treated were receiving combination treatment with two or more blood pressure-lowering drugs [13]. Although it might be thought that blood pressure control would be better in stroke survivors, given the frequency of severe disability, this does not appear to be the case. The authors quote similar findings in studies conducted in Melbourne (Australia), France and the United States [14–16]. Our own survey of cardiovascular risk perception and evidence treatment gaps in Australian general practice (the AusHEART Study) paints a similar picture [17,18]. Only 50% of patients with established CVD were prescribed a combination of a blood pressure-lowering medication, a statin and an antiplatelet agent, while only 34% of high-risk patients without established CVD were treated in this manner [17]. Even more discouraging for those interested in stroke, only 42% of patients with previous stroke or transient ischaemic attack received such combinations, compared with 73% of those with coronary disease [18]. Furthermore, general practitioners only recognized 27% of patients with a previous stroke or transient ischaemic attack as being at ‘high risk’ of recurrent events, while only 8% of such patients rated themselves as ‘high risk’ [18]. The obvious question is ‘why are we doing so badly?’ The problems of poor compliance with guideline recommendations and of a large evidence-treatment gap have long been recognized in relation to the management of hypertension and clearly arise in part because hypertension per se is usually an asymptomatic risk factor. It is far too simple to blame primary care physicians for these failures. We have to question whether we too, the so-called experts or opinion leaders in this field, have failed to send clear, coherent and consistent messages. The record of the past 15 years is that for the first part of the twenty-first century so far, the advice promulgated by all guidelines was for intensification of treatment, with lower blood pressure thresholds and targets for initiation of drug therapy, especially for high-risk groups. On the other hand, for the past few years, we have progressively revised these recommendations, and recommended higher thresholds and targets. This is plain from examination of American, European and International Guidelines issued this century [19–26]. Even worse, we now have significant differences between the recommendations for threshold and targets issued by the various recent guidelines [22–26], particularly for elderly patients, which of course is the most affected age group for patients with stroke. Furthermore, we now have a situation with open disagreement within the committee appointed to the Eighth Joint National Committee in the United States, with a dissenting report, focusing on these thresholds and targets, published within months of the first report [22,26]. In part, this situation arises from progressive insistence by responsible authorities that treatment recommendations should be firmly based on evidence from high-quality randomized clinical trials, at a time when the evidence from such trials is incomplete. In part, it arises from conflicting views about available evidence, such as that concerning J curves. In relation to stroke, there is a further source of disagreement or concern, and that arises from enduring concerns regarding the risk and benefits of lowering blood pressure in patients with acute ischaemic stroke, which may well spill over to influence the treatment of patients with previous ischaemic stroke. These factors all point in one direction, to the need for more clinical trials, particularly large-scale, rigorous trials aimed at defining thresholds, and targets for a large variety of patient groups and situations. Although some trials are already underway, it may take quite some time before the gap is plugged. Meanwhile, we should focus on better strategies for implementation of those treatment recommendations for which all experts, authorities and guidelines agree, as our record is not great even in those situations. The task ahead is considerable! ACKNOWLEDGEMENTS Conflicts of interest The author is the Co-Principal Investigator and Chair of the Steering Committee for the INTERACT2 and ENCHANTED trials in acute stroke and the PROGRESS trial in patients with previous stroke or TIA. He has received research grants from Servier for the PROGRESS and ADVANCE trials. The author also received honoraria and travel support from Servier for speaking about these studies at scientific meetings.