Vivienne E. Smith

Clinical factors associated with calcific aortic valve disease

Abstract Objectives. The aim of this study was to determine the prevalence of aortic sclerosis and stenosis in the elderly and to identify clinical factors associated with degenerative aortic valve disease. Background. Several lines of evidence suggest that degenerative aortic valve disease is not an inevitable consequence of aging and may be associated with specific clinical factors. Methods. In 5,201 subjects ≥65 years of age enrolled in the Cardiovascular Health Study, the relation between aortic sclerosis or stenosis identified on echocardiography and clinical risk factors for atherosclerosis was evaluated by using stepwise logistic regression analysis. Results. Aortic valve sclerosis was present in 26% and aortic valve stenosis in 2% of the entire study cohort; in subjects ≥75 years of age, sclerosis was present in 37% and stenosis in 2.6%. Independent clinical factors associated with degenerative aortic valve disease included age (twofold increased risk for each 10-year increase in age), male gender (twofold excess risk), present smoking (35% increase in risk) and a history of hypertension (20% increase in risk). Other significant factors included height and high lipoprotein(a) and low density lipoprotein cholesterol levels. Conclusions. Clinical factors associated with aortic sclerosis and stenosis can be identified and are similar to risk factors for atherosclerosis. (J Am Coll Cardiol 1997;29:630–4)

Prevalence of atrial fibrillation in elderly subjects (the Cardiovascular Health Study)

Atrial fibrillation (AF) is a common arrhythmia in elderly persons and a common cause of embolic stroke. Most studies of the prevalence and correlates of AF have used selected, hospital-based populations. The Cardiovascular Health Study is a population-based, longitudinal study of risk factors for coronary artery disease and stroke in 5,201 men and women aged > or = 65 years. AF was diagnosed in 4.8% of women and in 6.2% of men at the baseline examination, and prevalence was strongly associated with advanced age in women. Prevalence of AF was 9.1% in men and women with clinical cardiovascular disease, 4.6% in patients with evidence of subclinical but no clinical cardiovascular disease, and only 1.6% in subjects with neither clinical nor subclinical cardiovascular disease. A history of congestive heart failure, valvular heart disease and stroke, echocardiographic evidence of enlarged left atrial dimension, abnormal mitral or aortic valve function, treated systemic hypertension, and advanced age were independently associated with the prevalence of AF. The low prevalence of AF in the absence of clinical and subclinical cardiovascular disease calls into question the existence and clinical usefulness of the concept of so-called lone atrial fibrillation in the elderly.

M-Mode echocardiographic predictors of six- to seven-year incidence of coronary heart disease, stroke, congestive heart failure, and mortality in an elderly cohort (the cardiovascular health study)

Previous studies have identified a number of echocardiographic variables that predict cardiovascular disease (CVD) events and mortality, but have not focused on a large elderly cohort. The purpose of this study was to determine whether M-mode echocardiographic variables predicted all-cause mortality, incident coronary heart disease (CHD), congestive heart failure (CHF), and stroke in a large prospective, multicenter, population-based study. In the Cardiovascular Health Study, a biracial cohort of 5,888 men and women (mean age 73 years) underwent 2-dimensional M-mode echocardiographic measurements of left ventricular (LV) internal dimensions, wall thickness, mass and geometry, as well as measurement of left atrial dimension and assessment for mitral annular calcium. Participants were followed for 6 to 7 years for incident events; analyses excluded subjects with prevalent disease. One or more echocardiographic measurements were independent predictors of all-cause mortality and incident CHD, CHF, and stroke. After adjustment for anthropometric and traditional CVD risk factors, LV mass was significantly related to incident CHD, CHF, and stroke. The highest quartile of LV mass conferred a hazards ratio of 3.36, compared with the lowest quartile, for incident CHF. Furthermore, incident CHF-free survival was significantly lower for participants with LV mass in the highest versus the 2 lowest quartiles (86% vs 97%, respectively, at 2,500 days). Eccentric and concentric LV hypertrophy, respectively, conferred adjusted hazards ratios, compared with normal LV geometry, of 2.05 and 1.61 for incident CHD, and 2.95 and 3.32 for incident CHF. Thus, in an elderly biracial population, selected 2-dimensional M-mode echocardiographic measurements were important markers of subclinical disease and conferred independent prognostic information for incident CVD events, especially CHF and CHD.

Effect of African-American Race and Hypertensive Left Ventricular Hypertrophy on Coronary Vascular Reactivity and Endothelial Function

Excess cardiovascular morbidity and mortality among African (black) Americans remains an important yet unexplained public health problem. One possible explanation proposes that intrinsic or acquired abnormalities in coronary vascular reactivity and endothelial function result in excess ischemia among black Americans. To examine this hypothesis, we subjected 80 individuals with normal coronary arteries to invasive testing of coronary artery and microvascular relaxation using intracoronary infusions of acetylcholine and adenosine, a Doppler tipped intracoronary guide wire, and quantitative coronary angiography. We measured the percent increase in coronary blood flow and epicardial diameter after graded infusion of intracoronary acetylcholine and in coronary blood flow after intracoronary adenosine in 31 normotensive subjects (10 black, 21 white) and 49 hypertensive subjects with left ventricular hypertrophy (25 black, 24 white). Categorical and multivariate analyses revealed that in response to intracoronary adenosine and acetylcholine, the depression in endothelium-independent and -dependent microvascular relaxation during peak agonist effect was largely related to the presence of chronic hypertension and left ventricular hypertrophy. Normotensive subjects demonstrated no intrinsic racial differences in conduit and resistance vessel vasoreactivity. In response to maximal infusion of acetylcholine, epicardial coronary arteries constricted similarly in black and white subjects with hypertensive left ventricular hypertrophy and dilated similarly in normotensive black and white subjects. Thus, our study shows that in a cohort of black and white subjects referred for coronary arteriography because of chest pain, African American race is not associated with excess intrinsic or acquired depression in coronary vascular relaxation during the peak effect of the endothelium-dependent and -independent agonists acetylcholine and adenosine, after adjustment for the presence of left ventricular hypertrophy.

The presence of African American race predicts improvement in coronary endothelial function after supplementary L-arginine☆

OBJECTIVESnThe purpose of our study was to determine if the presence of African American ethnicity modulates improvement in coronary vascular endothelial function after supplementary L-arginine.nnnBACKGROUNDnEndothelial dysfunction is an early stage in the development of coronary atherosclerosis and has been implicated in the pathogenesis of hypertension and cardiomyopathy. Amelioration of endothelial dysfunction has been demonstrated in patients with established coronary atherosclerosis or with risk factors in response to infusion of L-arginine, the precursor of nitric oxide. Racial and gender patterns in L-arginine responsiveness have not, heretofore, been studied.nnnMETHODSnInvasive testing of coronary artery and microvascular reactivity in response to graded intracoronary infusions of acetylcholine (ACh) +/- L-arginine was carried out in 33 matched pairs of African American and white subjects with no angiographic coronary artery disease. Pairs were matched for age, gender, indexed left ventricular mass, body mass index and low-density lipoprotein cholesterol.nnnRESULTSnIn addition to the matching parameters, there were no significant differences in peak coronary blood flow (CBF) response to intracoronary adenosine or in the peak CBF response to ACh before L-arginine infusion. However, absolute percentile improvement in CBF response to ACh infusion after L-arginine, as compared with before, was significantly greater among African Americans as a group (45 +/- 10% vs. 4 +/- 6%, p = 0.0016) and after partitioning by gender. The mechanism of this increase was mediated through further reduction in coronary microvascular resistance. L-arginine infusion also resulted in greater epicardial dilator response after ACh among African Americans.nnnCONCLUSIONSnWe conclude that intracoronary infusion of L-arginine provides significantly greater augmentation of endothelium-dependent vascular relaxation in those of African American ethnicity when compared with matched white subjects drawn from a cohort electively referred for coronary angiography. Our findings suggest that there are target populations in which supplementary L-arginine may be of therapeutic benefit in the amelioration of microvascular endothelial dysfunction. In view of the excess prevalence of cardiomyopathy among African Americans, pharmacologic correction of microcirculatory endothelial dysfunction in this group is an important area of further investigation and may ultimately prove to be clinically indicated.

African Americans With LVH Demonstrate Depressed Sensitivity of the Coronary Microcirculation to Stimulated Relaxation

Abstract—Excess coronary heart disease morbidity and mortality among African Americans remains an important yet unexplained public health problem. We hypothesized that adverse outcome is in part due to intrinsic or acquired abnormalities in coronary endothelial function and vasoreactivity. We compared dose-response curves relating changes in coronary blood flow and epicardial diameter to graded infusions of acetylcholine in 50 African American and 65 white subjects with hypertensive left ventricular hypertrophy (LVH) and normal coronary arteries. These groups were similar for age, body mass index, mean arterial pressure, and indexed left ventricular mass. The same protocol was conducted in 24 normotensive African American and 56 similar white subjects. We found significant depression in the coronary blood flow dose-response curve relation among African Americans when compared with white subjects with similar LVH (P <0.03). Racial differences were observed at all doses of acetylcholine but were less precisely estimated at the highest dose. The same testing among normotensive subjects revealed similar dose-response curves with no significant effect of race. Qualitatively similar results were found with respect to coronary diameter. Adenosine responses, a measure of endothelium-independent function, were similar after partitioning by LVH. Our study demonstrates that there are racial differences in sensitivity of coronary arteries to acetylcholine-stimulated relaxation among those with LVH. These results provide a mechanism whereby racial differences in coronary vasoreactivity might contribute to adverse coronary heart disease outcome among African Americans, a group in whom LVH is prevalent.

Coronary vasomotor reactivity among normotensive African and white American subjects with chest pain

BACKGROUND AND OBJECTIVESnExcess cardiovascular morbidity and mortality among African (black) Americans is the subject of intensive investigation but the etiology remains speculative. One hypothesis proposes that inherent, or intrinsic, differences in coronary vascular reactivity and endothelial function predispose African Americans to enhanced vasoconstriction and/or depressed vasodilation, resulting in excess ischemia. The objective of this study was to establish whether coronary vasoreactivity differs among normotensive, nondiabetic African and white Americans with normal arteries referred for coronary arteriography because of chest pain.nnnPATIENTS AND METHODSnEleven African American (8 female, 3 male) and 28 white American (9 female, 19 male) normotensive, euglycemic patients with normal coronary arteries were prospectively recruited for invasive testing of coronary artery and microvascular relaxation using the endothelium-dependent and -independent agents, acetylcholine and adenosine; a Doppler tipped intracoronary guidewire; and quantitative coronary angiography.nnnRESULTSnThe study cohort consisted of 17 women (44%) and 22 men (56%) with a mean age of 46 +/- 10 yrs. Of 8 African American women, 6 were premenopausal and 2 were postmenopausal on estrogen replacement therapy. Of 9 white American women, 2 were premenopausal, 1 was 46-year old with a previous history of hysterectomy without ovariectomy, 2 were postmenopausal on estrogen replacement therapy, 2 were perimenopausal and 44- and 54-year old, and 2 were postmenopausal without estrogen replacement therapy. In response to maximal infusion of acetylcholine, epicardial coronary arteries and resistance vessels dilated similarly in black and white subjects. Dose-response curves revealed no significant racial differences during submaximal graded infusion of acetylcholine. In response to peak effect of adenosine, there were no racial differences in dilation of the microcirculation.nnnCONCLUSIONSnIn the absence of hypertension, diabetes mellitus, and angiographic evidence of coronary artery disease, African American women demonstrate no evidence of intrinsic predisposition to enhanced coronary conduit vasoconstriction or depressed microcirculatory dilation in response to the endothelium-dependent and -independent vasodilator agonists-acetylcholine and adenosine-when compared with responses of similar white men and women. Because of low enrollment of black males, definitive conclusions cannot be drawn regarding this group.

Coronary vasomotor function in a normotensive, nondiabetic referral population with normal coronary arteriograms

In a referral normal cardiac population, endothelium-independent coronary relaxation is nearly always normal, but endothelium-dependent relaxation may be depressed in a significant proportion of patients. Further study of the natural history of referral subjects with endothelial dysfunction is necessary to assess the potential cardiovascular risk of this finding in a presumed low-risk population.

753-4 Transesophageal Echocardiography in Patients with Blunt Chest Trauma

Rupture of the aorta resulting from blunt chest trauma (BCT) is often fatal. Early diagnosis and surgical treatment improves the chances of survival. Transesophageal echocardiography (TEE) permits accurate and rapid visualization of the thoracic aorta and is ideal in evaluating such patients. We performed TEE as the initial diagnostic procedure in 141 patients (pts) with BCT. 90% had a widened mediastinum on chest x-ray (CXR) as an indication of possible aortic damage. 92% of studies were performed in the emergency room. Sixty pts were on mechanical ventilatory support. Passage of the scope was difficult in 2 pts. Nine developed transient hypoxemia, one requiring mechanical ventilation. Findings 116 pts (82%) had no evidence of aortic trauma on TEE. Aortic disruption was noted in 6 pts (4%). 5 of whom underwent surgery and survived. In 15 pts the findings were indeterminate. Aortogram in these pts were negative for trauma. Disruption involving the distal arch was missed in 2 pts. Both died. Conclusions (1) TEE may be safely and rapidly performed in pts with BCT despite a high proportion being critically ill. (2) Alow yield of aortic disruption is obtained when the pre-test probability is low. (3) Early identification of aortic disruption by TEE and prompt surgical management improves survival. (4) Correct identification of disruption may be difficult in some cases where there is inadequate visualization of the aorta. (5) The diagnostic accuracy in identifying aortic disruption may be improved by the newer multiplanar TEE imaging modalities and by increasing operator experience with TEE in BCT pts, making this the procedure of choice in cases of suspected aortic disruption.