New concepts and paradigms in cardiovascular medicine: the noninvasive management of coronary artery disease

The effects of prophylactic coronary revascularization or medical management on patient outcomes after noncardiac surgery - a meta-analysis

PURPOSE

The benefits of prophylactic coronary revascularization for patients undergoing noncardiac surgery are uncertain. The purpose of this study was to systematically evaluate the effect of coronary revascularization and medical management on short- and long-term outcomes after noncardiac surgery.

METHOD

Ten electronic databases including MEDLINE and EMBASE (1980 to February 2006), and bibliographies of included articles were searched without language restrictions. Studies comparing effects of coronary revascularization and medical management before noncardiac surgery were included. Patient outcome data including perioperative mortality, myocardial infarction, long-term mortality, or late adverse cardiac events were extracted and entered into a meta-analysis.

RESULTS

The quality of published evidence was modest, comprising one randomized controlled trial and six retrospective studies. A total of 3,949 patients undergoing high-risk noncardiac surgery were included in the quantitative analysis. There was no significant difference between coronary revascularization and medical management groups with regards to postoperative mortality and myocardial infarction; the odds ratios (95% confidence intervals) were 0.85 (0.48-1.50) and 0.95 (0.44-2.08), respectively. There were no long-term outcome benefits associated with prophylactic coronary revascularization; the odds ratios (95% confidence intervals) were 0.81 (0.40-1.63) and 1.65 (0.70-3.86) for long-term mortality and late adverse cardiac events, respectively.

CONCLUSION

In patients with stable coronary artery disease, prophylactic coronary revascularization before high-risk noncardiac surgery does not confer any beneficial effects, when compared with optimized medical management, in terms of perioperative mortality, myocardial infarction, long-term mortality, or adverse cardiac events.

Intensive lifestyle modification: impact on cardiovascular disease risk factors in subjects with and without clinical cardiovascular disease

Intensive lifestyle modification programs are intended to stabilize or promote regression of coronary artery disease; however, clinical response is often nonuniform, complicating appropriate utilization of resources and prediction of outcome. This study assessed physiological and psychological benefits to 72 persons participating in a prospective, nonrandomized, four-component lifestyle change program and compared response between patients with clinical cardiovascular disease (CVD) and patients with elevated risk factors for CVD but without clinical manifestations of disease. Subjects entering the program due to elevated risk factor levels alone demonstrated equal or greater benefit, in terms of improvement in primary CVD risk factors and reduction in measures of coronary disease risk developed in the Framingham Heart Study, than those with clinical CVD. These findings suggest that intensive lifestyle change programs may be important for primary prevention in individuals at increased risk of CVD.

Statin and aspirin therapy are associated with decreased rates of choroidal neovascularization among patients with age-related macular degeneration

PURPOSE

To investigate the relationship between statin and aspirin use and the risk of choroidal neovascularization (CNV) in patients with age-related macular degeneration (AMD).

DESIGN

Retrospective consecutive case series.

METHODS

All patients 60 years and older with AMD who were seen between January 1, 1990, and March 1, 2003, at the San Francisco Veterans Affairs Hospital Eye Clinic with fundus photographs were included. Patients with other diagnoses predisposing to CNV or incomplete medical records were excluded. The main outcome measure was angiographically evident CNV. Diagnosis was based on review of fundus photographs and fluorescein angiograms in masked fashion; medical records were reviewed for variables possibly predisposing to CNV or statin use. For patients with CNV, age of onset was recorded; those without CNV were treated as censored. Age-related macular degeneration disease status and time of onset of CNV was compared between patients treated or not treated with statins for at least 6 months.

RESULTS

Of 326 patients with AMD, 104 had CNV, 204 had dry AMD, and 18 had geographic atrophy (GA). Of CNV subjects, 21 (20%) used statins, compared with 77 (38%) of dry AMD subjects without GA and 6 (33%) of controls with GA (hazard ratio = 0.51, 95% confidence interval (CI) = 0.31-0.86, P =.01). Aspirin use was also significantly associated with decreased rates of CNV; 62 CNV subjects (60%) used aspirin, compared with 154 (75%) dry AMD subjects without GA or 12 (67%) with GA (hazard ratio = 0.63, 95% CI = 0.40-0.98, P =.04).

CONCLUSIONS

Therapy with statins or aspirin is associated with decreased rates of CNV among AMD patients. Additional study with a prospective and/or randomized trial of statin and aspirin use in AMD patients is warranted.

Physicians' judgments of survival after medical management and mortality risk reduction due to revascularization procedures for patients with coronary artery disease

STUDY OBJECTIVE

s: To assess the accuracy of physicians' judgments of survival probability for medically managed patients with coronary artery disease (CAD), and of the absolute risk reduction of mortality due to coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) for such patients; and relationships among these judgments and the physicians' propensity to perform revascularization.

DESIGN

Two surveys (for three-vessel or two-vessel CAD) for patients presenting with stable CAD, currently managed medically, and without other life-limiting problems.

SETTING

Multiple educational conferences, 1996-1997.

PARTICIPANTS

Conference attendees.

MEASUREMENTS AND RESULTS

Main outcomes were proportions of patients for whom the physicians would recommend revascularization (CABG for three-vessel CAD, CABG or PTCA for two-vessel CAD), and judgments of the proportions of medically managed patients who would be alive after 5 years, 7 years, and 11 years, and of absolute risk reduction of mortality due to CABG (or PTCA for two-vessel CAD). At least one half of the participants judged the survival rate of medically managed patients with three-vessel or two-vessel CAD to be less than the lowest rates supported by the best available evidence. More than one fourth judged the absolute risk reduction due to CABG to be higher than the highest values based on such evidence. Physicians' propensity to perform revascularization correlated inversely with their judgments of survival given medical management, and with their judgments of absolute risk reduction due to revascularization.

CONCLUSIONS

Physicians may overuse revascularization because of excessive pessimism about survival of medically managed patients, and excessive optimism about the survival benefits of revascularization.

Myocardial blood flow quantification with MRI by model-independent deconvolution

Magnetic resonance (MR) imaging during the first pass of an injected contrast agent has been used to assess myocardial perfusion, but the quantification of blood flow has been generally judged as too complex for its clinical application. This study demonstrates the feasibility of applying model-independent deconvolution to the measured tissue residue curves to quantify myocardial perfusion. Model-independent approaches only require minimal user interaction or expertise in modeling. Monte Carlo simulations were performed with contrast-to-noise ratios typical of MR myocardial perfusion studies to determine the accuracy of the resulting blood flow estimates. With a B-spline representation of the tissue impulse response and Tikhonov regularization, the bias of blood flow estimates obtained by model-independent deconvolution was less than 1% in all cases for peak contrast to noise ratios in the range from 15:1 to 20:1. The relative dispersion of blood flow estimates in Monte Carlo simulations was less than 7%. Comparison of MR blood flow estimates against measurements with radio-isotope labeled microspheres indicated excellent linear correlation (R2 = 0.995, slope: 0.96, intercept: 0.06). It can be concluded from these studies that the application of myocardial blood flow quantification with MRI can be performed with model-independent methods, and this should support a more widespread use of blood flow quantification in the clinical environment.

Rationale and design of the St. Francis Heart Study: a randomized clinical trial of atorvastatin plus antioxidants in asymptomatic persons with elevated coronary calcification

Early detection of asymptomatic subjects who are at risk for future cardiovascular events may allow for earlier medical treatment in order to prevent disease progression and future events. Electron-beam computed tomography accurately identifies people with increased coronary calcification, which is correlated with increased coronary plaque mass, increased likelihood of obstructive coronary disease, and increased likelihood of future cardiovascular events. The St. Francis Heart Study is a single-center combination study of men and women 50-70 years old that includes a natural history study of the relation between calcium scores and cardiovascular events (n = 5582), the association of calcium scores with traditional and nontraditional coronary disease risk factors (n = 1160), and a randomized clinical trial designed to assess the benefit of combination treatment with atorvastatin, vitamin C, and vitamin E, as compared to placebos, in subjects with elevated age- and gender-adjusted coronary calcification (n = 1007). Mean follow-up duration will be 4 years. The study is proceeding on schedule with anticipated completion by August 2002. It should provide important information regarding the benefits of treating asymptomatic men and women who have elevated coronary artery calcium, using cholesterol reduction and antioxidant therapy. The article describes the design of the St. Francis Heart Study.

The endothelium: dysfunction and beyond

Since its anatomic discovery in the 19th century, the endothelium was considered to fulfill no other purpose than that of a physical barrier between blood and tissue, until Furchgott and colleagues defined endothelium-dependent vasoreactivity in the late 1970s. Henceforth, a functional paradigm defined the balance between endothelium-derived relaxing factors and endothelium-derived contracting factors as the hallmark of endothelial cell integrity. As a consequence, any reflection of a deviation from this state was defined as endothelial dysfunction, most notably the impairment of vasorelaxation in response to pharmacologic stimuli such as acetylcholine or nonpharmacologic stimuli such as shear stress and cold pressor. Within the coronary artery tree these alterations have been recognized before the development of obstructive coronary artery disease, affecting the microcirculation before the epicardial conduit vessel. Furthermore, recent clinical trials outlined the prognostic significance of these changes, whereby impairment of increase in coronary blood flow in response to endothelium-dependent stimuli seemed to be of utmost importance. Thus it is intriguing to speculate on the evolving role of myocardial perfusion imaging in combination with pharmacologic and nonpharmacologic stimuli for the noninvasive assessment of coronary endothelial dysfunction in patients at risk for future adverse events. At a minimum, this review aims to put endothelial dysfunction into an imaging perspective beyond the scope of the conventional approach.

Drug therapy or coronary angioplasty for the treatment of coronary artery disease: new insights

BACKGROUND

In the last decade percutaneous transluminal coronary angioplasty has become a very popular strategy for the treatment of coronary artery disease, although its efficacy in reducing ischemic events and the subsequent need for revascularization has yet to be proved.

METHODS

We reviewed the latest trials that compared percutaneous transluminal coronary angioplasty and medical therapy.

RESULTS

We discuss the potentially favorable effect of lipid-lowering therapy on coronary atherosclerosis and cardiac events and comment on the results of the recent Atorvastatin Versus Revascularization Treatments (AVERT) study that compared lipid-lowering treatment and percutaneous transluminal coronary angioplasty in patients with stable coronary artery disease.

CONCLUSIONS

Medical treatment aimed at reversing plaque growth and promoting plaque stabilization should probably be considered as the initial therapeutic option. Statin class drugs, together with aggressive management of known risk factors, show promise as the first step after appropriate early diagnosis. Revascularization procedures should subsequently be considered for all patients who do not respond to medical treatment or in whom the disease shows clear signs of progression.

Adenosine-induced coronary flow reserve in Watanabe heritable hyperlipidemic rabbits

The Watanabe heritable hyperlipidemic (WHHL) rabbit develops coronary atherosclerosis and hypercholesterolemia because of a genetic deficiency of low-density lipoprotein receptors and is therefore a good animal model for studying the relationships of coronary atherosclerosis, hypercholesterolemia and coronary flow reserve. The aim of the present study was to assess myocardial perfusion at baseline and during adenosine infusion (0.2 mg x kg(-1) x min(-1)) in 8 WHHL rabbits (13.8+/-0.5 months) with 13N-ammonia, small-animal positron emission tomography (PET) and colored microspheres. Results were compared with those from 6 age-matched Japanese white rabbits. Plaque distribution was also examined in the extramural coronary arteries. All 8 WHHL rabbits had coronary plaques, with 6 showing multiple plaques. Mean global myocardial blood flow (ml x min(-1) x g(-1)) did not differ significantly between control and WHHL groups both at baseline (3.67+/-0.72 vs 4.26+/-1.12 ml x min(-1) x g(-1), p=NS) and with adenosine (7.92+/-2.00 vs 9.27+/-2.91 ml x min(-1) x g(-1), p=NS), nor did coronary flow reserve (2.16+/-0.37 vs 2.18+/-0.41, p=NS). None showed evidence of regional perfusion abnormalities by visual and semiquantitative analyses of PET images. It was concluded that WHHL rabbits preserve adenosine-induced coronary flow reserve despite coronary atherosclerosis and hypercholesterolemia, suggesting that a compensatory mechanism develops in this animal model.

Functional foods: the US perspective

Widespread interest in the possibility that selected foods might promote health has resulted in the coining of the term functional food, although agreement about what is and what is not a functional food is lacking. Public interest in functional foods is increasing because of higher health care costs; the passage of federal legislation affecting many food categories, including the expanded category of dietary supplements; and recent scientific discoveries linking dietary habits with the development of many diseases, including coronary heart disease and some cancers. A variety of foods have been proposed as providing health benefits by altering one or more physiologic processes. Biomarkers are needed to assess the ability of functional foods or their bioactive components to modify disease and to evaluate the ability of these foods to promote health, growth, and well-being. Evidence suggests that several biomarkers may be useful for distinguishing between diseased and nondiseased states and even for predicting future susceptibility to disease. A variety of biomarkers will probably be needed to develop a profile for an individual that reflects the impact of diet on performance and health. Another area of interest is the interaction of nutrients and their association with genetics. These interactions may account for the inconsistent interrelations observed between specific dietary constituents and the incidence of disease. Greater understanding of how diet influences a person's genetic potential, overall performance, and susceptibility to disease can have enormous implications for society. As new discoveries are made in this area, consumers will need access to this information so that they can make informed decisions.