Incidence of stroke

Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins) have been shown to improve vascular outcomes due to their cholesterol-lowering effects as well as multiple pleiotropic effects. In high-risk populations, statin therapy is known to reduce the risk of vascular events such as myocardial infarction and stroke. A meta-analysis of 10 trials involving 79,494 subjects showed that statin therapy reduced the incidence of stroke by 18%, major coronary events by 27%, and all-cause mortality by 15%. The SPARCL trial recently showed that high-dose HMG-CoA reductase inhibitors prevent recurrent stroke and transient ischemic attacks. ... 

Early detection of ischemic stroke can be done with the use of transcranial Doppler ultrasonography. In the Stroke Prevention Trial in Sickle Cell Anemia (STOP) study, screening with this method followed by transfusion significantly reduced the incidence of stroke.29 Screening is recommended in all patients over 2 years of age. 

Aspirin is maximally effective as an antithrombotic agent at the comparatively low dose of 81 to 325 mg per day. (The antipyretic dose of aspirin in adults is 325 to 650 mg every 4 h.) Higher doses of aspirin are actually contraindicated in patients prone to thromboembolism. At higher doses, aspirin also reduces synthesis of prostacyclin, another arachidonic acid metabolite. Prostacyclin normally inhibits platelet aggregation. The prophylactic administration of low-dose aspirin has been shown to increase survival following myocardial infarction, decrease incidence of stroke, and assist in maintenance of patency of coronary bypass grafts. 

Keli SO, Hertog MG, Feskens EJ, Kromhout D. 1996. Dietary flavonoids, antioxidant vitamins, and incidence of stroke the Zutphen Study. Arch Intern Med 156 637-642. 

Coronary heart disease is one of the leading causes of death in the industrialized world (Packer, 1992 Remme and Swedberg, 2001). Hypertension is a risk factor for cardiovascular disease and is associated with an increased incidence of stroke and coronary heart disease. Other risk factors for cardiovascular disease include also high cholesterol, diabetes, and obesity. Although there have been many advances in treatment over the past several decades, less than a quarter of all hypertensive patients have their blood pressure adequately controlled with available therapies. 

Little Is known about possible long-term effects of CS Inhalation. This is due In part to the fact that short-term experiments with experimental animals, carried out for from several days to a month and using much higher (In some cases, nearly lethal) concentrations of CS, showed that ocular, respiratory, and cutaneous alte-. rations were mild and readily reversible, whereas necropsy findings failed to reveal any evidence of systemic alterations. Retrospective studies performed by the Hlmsworth committee at the request of the British Parliament after the extensive use of CS in Northern Ireland showed that no adverse effects of CS use were observed, with respect to eye burns, residual respiratory tract injury, Increased death rate in the elderly, exacerbations of mental Illness, increased Incidence of strokes or heart attacks, or incidence of tuberculosis. At exposure concentrations reported by the Hlmsworth committee (about 90 mg-min/m ), no persistent or notably adverse health effects were observed. 

ABSTRACT Several epidemiological studies have found an inverse correlation between the dietary flavonoid intake and a reduced mortality from coronary heart disease and the incidence of stroke. We will focus our review on several mechanisms which have been suggested to explain these protective effects. 

Additionally, men in the highest quartile of flavonol and flavone intake showed a reduced incidence of stroke in a Dutch cohort [18], while a prospective study in postmenopausal women found no association between total flavonoid intake and stroke mortality [15],... 

Establishment of definable end-points for the investigation of specific differences between normal and abnormal responders poses another problem. Consider the evaluation of drug treatment of hypertension as a case in point. In this instance, the definitive end-point would be measured by the difference in the incidence of strokes and cardiovascular disease between normal and abnormal drug responders, but this would probably occur years after the trait is recognized and modifying treatment undertaken. Another example of pharmacogenetic interest... 

Brain injury from stroke is a major public health problem in most industrialized countries in the world. For example, in the United States over 0.5 million cases of stroke occur annually, the incidence of stroke doubles approximately each decade over the age of 45 and occurs in up to 2% in those over 75. Frequently, stroke causes major disability with the patient having difficulty in communication, ambulation and movement, or in reasoning. Fortunately, the incidence and severity of stroke has been reduced in many countries by the introduction of preventative measures aimed at controlling hypertension, hypercholesterolaemia, smoking and by the use of anticoagulants in high risk groups. 

I I Tunick PA, et al. Effect of treatment on the incidence of stroke and other emboli in 519 patients with severe thoracic aortic plaque. Am J Cardiol 2002 90(12) 1320-1325. 

Sudlow C, Warlow CP (1997) Comparable studies of the incidence of stroke and its pathological types results from an international collaboration. Stroke 28 491-499 Tsushima Y, Tanizaki Y, Aoki J et al (2002) Detection of microhemorrhage in neurologically healthy adults. Neuroradiology 44 31-36... 

Stroke mortality rises rapidly with age (Rothwell et al. 2005). The increase in mortality in the elderly is mainly a result of the steep rise in the incidence of stroke with age, but also, to a lesser extent, reflects the increase in case fataUty in older patients. In other words, older people are more likely to have a stroke (incidence) and, if they do have one, it is more likely to be fatal (case fatality). 

The OXVASC study showed that the annual incidence of stroke in the UK in the first few years of this century, including subarachnoid hemorrhage, was 2.3/1000 and the incidence of TIA was 0.5/1000 (Rothwell et al. 2005), with about a quarter of events occurring in those under the age of 65 and about a half in those above the age of 75 (Fig. 1.1). The incidence of cerebrovascular events in OXVASC was similar to that of acute coronary vascular events in the same population during the same period (Fig. 1.2), with a similar age distribution (Rothwell et al 2005). Incidence rates, however, measure first-ever-in-a-lifetime definite events only and exclude possible, recurrent and suspected events, so do not represent the true burden of a condition. This is especially true for TIA, where a significant proportion of cases referred to a TIA service have alternative, non-vascular... 

Wroe SJ, Sandercock P, Bamford J et al. (1992). Diurnal variation in the incidence of stroke the Oxfordshire Community Stroke Project. British Medical Journal 304 155-157 Wyller TB, Bautz-Holter E, Holmen J (1994). Prevalence of stroke and stroke-related disabihty in North Trondelag County Norway. Cerebrovascular Diseases 4 421-427... 

Vitamin C deficiency is associated with an increased risk of atherosclerosis, but there is little evidence of protective effects at intakes greater than needed to meet requirements (Jacob, 1998). A systematic review (Ness et al., 1996) found limited evidence of benefits of high intakes of vitamin C in reducing the incidence of stroke, but inconsistent evidence with respect to coronary heart disease. 

Shimokawa T, Moriuchi A, Hori T, Saito M, Naito Y, Kaba-sawa H, Nagae Y, Matsubara M, Okuyama H. Effect of dietary alpha-hnolenate/hnoleate balance on mean survival time, incidence of stroke and blood pressure of spontaneously hypertensive... 

Further support for using blood pressure as a surrogate endpoint is provided by the concordance of evidence from a number of clinical trials in which blood pressure lowering with low-dose diuretics and P-blockers was shown to reduce the incidence of stroke/ coronary artery disease/ and congestive heart failure in hypertensive patients (19). Of particular interest is a meta-analysis that was conducted to compare the extent of blood pressure reduction achieved in different clinical trials with the maximum benefit that was anticipated on epidemiolgic grounds (Table 17.3) (20). The decrease in stroke incidence anticipated for a 5- to 6-mm Hg average reduction in diastolic blood pressure was fully realized with only 2 to 3 years of antihypertensive therapy. 

In the UK Medical Research Council (MRC) trial, the outcome of antihypertensive treatment based on diuretics was compared with placebo in a very large number of hypertensive subjects (11). Treatment based on a thiazide did not increase the incidence of coronary events or sudden death indeed, thiazide-based treatment reduced the incidence of strokes by 67% and of all cardiovascular complications by 20%. It should be noted that the dose of bendroflumethiazide used in the MRC trial (lOmg/day) is now known to be unnecessarily high and that it was used without prophylaxis against hypokalemia. Even so, a subgroup analysis of data from the MRC Trial provided no evidence that the association between major electrocardiographic abnormalities and an increased likelihood of a clinical event was strengthened by bendroflumethiazide treatment (12). 

Even if the increase in mean blood pressure is probably modest (less than 5.0 mmHg) the clinical relevance of such an increase can be large, especially in elderly people. In fact, an overview of randomized clinical trials of antihypertensive treatment has shown that a 5-6 mmHg increase in diastolic blood pressure over a few years can be associated with a 67% increase in the incidence of strokes and a 15% increase in coronary heart disease (30). These effects are apparent in both normotensive and hypertensive patients. 

These findings are of potential clinical significance, because if the blood pressurelowering effects found in these short periods of treatment can be sustained over a longer period of time, the incidence of stroke may be reduced by 30-40% and coronary heart disease by 20-25% (Collins et al., 1990). 

Patients with atrial fibrillation or flutter may experience the entire range of symptoms associated with other supraventricular tachycardias, although syncope as a presenting symptom is uncommon. Since atrial kick is lost with the onset of atrial flbrillation, severe low-output states may result in forms of heart disease that rely heavily on atrial contraction to maintain cardiac output (such as mitral stenosis or hypertrophic obstructive cardiomyopathy see Chap. 18). An additional complication of atrial flbrillation is arterial embolization resulting from atrial stasis and poorly adherent mural thrombi. Of course, the most devastating complication in this regard is the occurrence of an embolic stroke. The overall incidence of stroke in patients with atrial... 

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