Seminars in Cerebrovascular Diseases and Stroke最新文献

Stroke is a common problem in the United States and causes significant morbidity and mortality. In addition both the personal and economic costs of stroke are high. Chronic arterial hypertension is the most significant modifiable risk factor for stroke (ischemic and hemorrhagic), both because of it's high relative risk for stroke and also because of it's prevalence in the general population. In addition hypertension remains under-recognized and under-treated. Newer studies have demonstrated that more aggressive treatment of hypertension results in lower cardiovascular morbidity and mortality, including that due to stroke. Consequently, new definitions for hypertension and new recommendations for treatment have recently been published. Furthermore, certain conditions, such as stroke, have been determined to be a “compelling indication” for certain classes of antihypertension therapy. Chronic hypertension is an important cause of the vascular pathology which leads to stroke and intracerebral hemorrhage. Acute stroke and cerebral hemorrhage may also cause an acute rise in blood pressure. Treatment of elevated blood pressure during acute stroke must balance the theoretical risk of worsening the stroke due to reduced cerebral perfusion against the benefits of lowering blood pressure (reduced risk of hemorrhage, cerebral edema, and other end-organ damage). This has been made more challenging since the approval of thrombolytic therapy for acute ischemic stroke. Also, severely elevated blood pressure can also cause hypertensive encephalopathy which must be distinguished from stroke so that appropriate treatment can be instituted as quickly as possible.

Hypertension is the most consistent and powerful predictor of stroke and is involved in nearly 70% of strokes. Placebo-controlled trials have proven that blood-pressure-lowering treatment reduces the incidence of stroke by 40% in middle-aged or older hypertensive patients with predominantly diastolic hypertension and by 30% in older patients with isolated systolic hypertension. Recent trials have compared new agents (calcium-channel blockers, α-blockers, angiotensin converting enzyme inhibitors or angiotensin type-1 receptor blockers) with old durg classes (diuretics or β-blockers). Calcium-channel blockers, including (−8%, P=0.07) or excluding verapamil (−10%, P=0.02), as well as angiotensin type-1 receptor blockers (−24%, P=0.0002) resulted in better stroke prevention than did the old drugs, whereas the opposite trend was observed for angiotension converting enzyme inhibitors (+10%, P=0.03). An overview of 6 trials conducted in patients with a history of cerebrovascular disease demonstrated that antihypertensive drug treatment reduced stroke recurrence by 25% (P=0.004). A meta-regression analysis showed that within-trial differences in systolic blood pressure accounted for the prevention of stroke in most trials. In 5 trials, dementia was a secondary outcome. Overall, antihypertensive treatment did not reduce the incidence of vascular or degenerative dementia (−11%, P=0.15). However, when the analysis was limited to 3 trials involving a dihydropyridine or a diuretic as the mainstay of therapy, this benefit increased to 25% (P=0.01). Randomized clinical trials should urgently address the question to what extent blood-pressure-lowering therapy may prevent degenerative dementia.

Individuals with a history of cerebrovascular disease have elevated risks of recurrent stroke, other cardiovascular events, and cognitive decline. In the Perindopril Protection Against Recurrent Stroke Study, 6,105 hypertensive and nonhypertensive individuals with a history of stroke or transient ischemic attack were randomly assigned active blood-pressure-lowering treatment (a flexible regimen that included perindopril and indapamide) or placebo. Over a mean follow-up period of 3.9 years, active treatment lowered the relative risks of stroke by 28%, major vascular events, major coronary events, and congestive heart failure each by 26%, and cognitive decline by 19%. The benefits observed were similar in those both with and without hypertension at baseline.

Stroke is associated with numerous health outcomes, the study of which is important for identifying best practices. However, it is equally important to understand the process to generating that knowledge. The methodological approach to stroke outcomes research is founded on first principles of epidemiological inquiry. These principles include defining the inquiry through a conceptual model; identifying and prioritizing the fundamental research questions; systematically addressing the research questions in order of importance; and exploring possible nuances to identified associations. To illustrate these principles in practice, the line of investigation into the reasons for racial/ethnic disparities in stroke mortality is used as a case study.

We have the ability to deliver outstanding health care in the United States, but fall far short of this goal. Between the health care system we have and the system we could have, lies not just a gap, but a chasm. Change is needed in physician behavior and in the health care system. We need to consider the value (ie, = quality/cost) of the medical care delivered in this country. There are limited resources, but there is much room for improvement.

Before long-term solutions can be found to maximize the quality of medical care, we must understand the need for change and what changes need to be made, how decisions are made, how changes in physician behavior occur, and the role of health care systems in making changes occur. This article reviews these topics and introduces a broader paradigm for clinical decision-making. It is an overview for those new to the field and provides a platform for those interested in further study.