Progress in cardiovascular diseases
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Prog Cardiovasc Dis · Jan 2007
ReviewMaking sense of noninferiority: a clinical and statistical perspective on its application to cardiovascular clinical trials.
Active control noninferiority trials are being used with increasing frequency in new drug or device development when standard placebo-controlled trials are considered unethical. Nevertheless, the design and analysis of these trials are founded on a number of assumptions and arbitrary criteria that are generally not well understood or justifiable. ⋯ When conservative criteria were applied to each of the key assumptions underlying 2 representative noninferiority trials, they materially undermined the conclusions regarding noninferiority failing to confirm reported conclusions regarding noninferiority despite enthusiastic dissemination and acceptance of the results. Because the clinical, regulatory, and economic impact of active control noninferiority trials is substantial, robust criteria should be used routinely in their design, analysis, and interpretation to reach their intended objectives and to keep them from becoming wasted efforts.
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Prog Cardiovasc Dis · Nov 2006
ReviewSystolic dysfunction in heart failure with a normal ejection fraction: echo-Doppler measurements.
Heart failure with a normal ejection fraction, also called heart failure with preserved ejection fraction or diastolic heart failure, is thought to be characterized by normal systolic function and disturbed diastolic function only. However, studies using newer Doppler-echocardiographic techniques have shown that ventricular function is not normal particularly in the long axis. Ejection is relatively preserved because of increased radial function. ⋯ The use of ejection fraction, which has a normal distribution, to dichotomize patients with heart failure is not supported on theoretical or experimental grounds, and any cutoff is arbitrary. Patients with heart failure have a mixture of systolic and diastolic abnormalities and variable degrees of remodeling. It is more important to correctly identify these in the individual patient.
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Cardiovascular complications are the major cause of perioperative morbidity and mortality of patients undergoing major vascular surgery. This is related to the frequent presence of an underlying coronary artery disease. This paper reviews the pathology of perioperative cardiac complications and cardiac risk assessment and risk reduction strategies. ⋯ Patients with 1 or 2 cardiac risk factors represent an intermediate-risk group for perioperative cardiac complications. If beta-blockers are prescribed, the probability of cardiac complications is low and there is no need for further noninvasive testing. Patients with 3 or more risk factors are at high risk for cardiac complications and the use of noninvasive testing may help further refine cardiac risk based on the presence and absence of test-induced myocardial ischemia. beta-Blockers should be prescribed to all patients, and coronary revascularization should be reserved for high-risk patients who have a clearly defined need for revascularization independent of the need for major vascular surgery.
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The arterial endothelium is a vital homeostatic cell layer responsible for a variety of functions such as thromboresistance, control of vessel tone, and vessel growth. Recent evidence has indicated that both active and passive cigarette smoking are associated with dysfunction of normal endothelial physiology, in a dose dependent and potentially reversible way. Endothelial abnormalities may predispose to the atherogenic and thrombotic problems associated with cigarette smoking.