Jeffrey A. Breall

Time to presentation with acute myocardial infarction in the elderly : Associations with race, sex, and socioeconomic characteristics

BackgroundAlthough prompt treatment is a cornerstone of the management of acute myocardial infarction (AMI), prior studies have shown that one fourth of AMI patients arrive at the hospital >6 hours after symptom onset. It would be valuable to identify individuals at highest risk for late arrival, but predisposing factors have yet to be fully characterized. Methods and ResultsData from the Cooperative Cardiovascular Project, involving Medicare beneficiaries aged >65 years hospitalized between January 1994 and February 1996 with confirmed AMI, were used to identify patients who presented “late” (≥6 hours after symptom onset). Patient characteristics were tested for associations with late presentation by use of backward stepwise logistic regression. Among 102 339 subjects, 29.4% arrived late. Significant predictors of late arrival (odds ratio, 95% CI) included diabetes (1.11, 1.07 to 1.14) and a history of angina (1.32, 1.28 to 1.35), whereas prior MI (0.82, 0.79 to 0.85), prior angioplasty (0.80, 0.75 to 0.85), prior bypass surgery (0.93, 0.89 to 0.98), and cardiac arrest (0.52, 0.46 to 0.58) predicted early presentation. Additionally, initial evaluation at an outpatient clinic (2.63, 2.51 to 2.75) and daytime presentation (1.67, 1.59 to 1.72) predicted late arrival. Finally, female sex, black race, and poverty, which were evaluated with an 8-level race–sex–socioeconomic status interaction term, were also risk factors for delay. ConclusionsDelayed hospital presentation is a common problem among Medicare beneficiaries with AMI. Factors associated with delay include not only clinical and logistical issues but also race, sex, and socioeconomic characteristics. Education efforts designed to hasten AMI treatment should be directed at individuals with risk factors for late arrival.

Intravascular Ultrasonic Analysis of Plaque Characteristics Associated With Coronary Artery Remodeling

We sought to determine the patient and plaque characteristics associated with the different forms of arterial remodeling as seen by intravascular ultrasound (IVUS) before coronary intervention. Remodeling in response to plaque accumulation may occur in the form of compensatory enlargement and/or focal vessel contraction. Previous studies report variation in the frequency and form of arterial remodeling. We performed preintervention IVUS imaging on 169 patients. Vessels were categorized as exhibiting compensatory enlargement or focal contraction if the arterial area at the lesion was larger or smaller, respectively, than both proximal and distal reference arterial areas; otherwise the artery was considered not to have undergone significant remodeling. Calcification was assessed and noncalcified plaque density was measured by videodensitometry. Sixty-one of 169 patients (66 narrowings) (46 men and 15 women, age 56+/-11 years) had adequate reference segments. Remodeling occurred in 43 of 66 patients (65%): compensatory enlargement in 27 of 66 (41%) and focal contraction in 16 of 66 (24%). Lesions with focal contraction had significantly smaller arterial area (13.3+/-3.3 vs. 18.1+/-7.0 mm2, p = 0.02) and plaque area (9.5+/-2.8 vs 13.7+/-5.5 mm2, p<0.01). Cross-sectional stenosis was similar (71+/-9% vs. 75+/-10%, p = NS), as was plaque density (p = 0.20), eccentricity, and calcium. Patient age, gender, and lesion location were not related to the form of remodeling. Similarly, history of diabetes, hypercholesterolemia, or hypertension was not predictive. Smoking was the only risk factor associated with focal contraction (p<0.01). Thus, whereas compensatory enlargement appears to be the most common form of coronary artery remodeling, focal contraction occurs more often in smokers.

Effect of diabetes mellitus and insulin use on survival after acute myocardial infarction in the elderly (The Cooperative Cardiovascular Project)

Using data from a retrospective cohort study of Medicare beneficiaries hospitalized with an acute myocardial infarction (AMI), we evaluated the role of diabetes mellitus on 30-day and 1-year mortality. We classified subjects as nondiabetics, diabetics controlled with diet alone, diabetics receiving an oral hypoglycemic agent, and diabetics on insulin at time of admission. We compared baseline admission characteristics of subgroups using chi-square and Wilcoxon rank-sum tests and evaluated the effect of each diabetic state using sequential logistic models. We identified 80,832 nondiabetic patients, 9,862 diet-controlled diabetic patients, 14,664 diabetics receiving an oral hypoglycemic agent, and 12,241 diabetic patients on insulin therapy. Although mean age was similar among the groups, prevalence of hypertension, prior AMI, prior congestive heart failure, and prior revascularization were higher among diabetic patients, particularly those taking insulin. Diabetic patients, particularly those taking insulin, were less likely to receive aspirin and beta blockers and to undergo coronary revascularization. Diabetic patients had higher 30-day and 1-year mortality than nondiabetic patients. After adjustment for demographics, clinical and hospital characteristics, and treatment strategies, insulin-treated diabetics had the highest risk of mortality, followed by diabetics receiving oral hypoglycemic agents, followed by diet-controlled diabetics. Thus, diabetes is highly prevalent among elderly patients with an AMI. Mortality rates for these patients, particularly insulin-using diabetics, are higher than among their nondiabetic counterparts. Preventive and therapeutic strategies must be developed to ensure improved short- and long-term outcomes for elderly patients with diabetes and AMI.

Bradycardia is associated with development of coronary collateral vessels in humans

BackgroundThe development of mature coronary collateral vessels in patients with obstructive coronary artery disease (CAD) decreases the ischemic myocardial burden. Chronic bradycardia has been shown to stimulate formation of collateral vessels in experimental models. ObjectiveTo test our hypothesis that CAD patients with bradycardia would have better developed collateral circulation than would members of a control group. DesignA retrospective study examining the relationship between bradycardia and the development of coronary collateral vessels in patients with obstructive CAD. MethodsAdmission electrocardiograms and rhythm tracings obtained during angiography of all patients presenting to the cardiac catheterization laboratory were screened from January to October 1997. Angiograms for patients with heart rates ≤ 50 beats/min were reviewed. An equivalent number of consecutive patients with heart rates ≥ 60 beats/min served as controls. Patients with acute myocardial infarction, with rhythms other than sinus, and without high grade obstructive CAD (< 70% stenosis) were excluded from the study. ResultsThe study population consisted of 61 patients, 30 having heart rates ≤ 50 beats/min (group A), and 31 controls with heart rates ≥ 60 beats/min (group B). A significantly greater proportion of patients in group A than of matched controls was demonstrated to have developed collaterals (97 versus 55% in group B, P  < 0.005). The mean collateral grades were 1.66 and 0.95 for subjects in groups A and B, respectively (P  < 0.001). CAD patients with bradycardia are more likely (odds ratio 24, 95% confidence interval 5–146) to have angiographic coronary collaterals than are those with higher heart rates. ConclusionResults of this study demonstrate that there is an association between bradycardia and growth of collateral vessels in patients with obstructive CAD. Bradycardic agents may be useful for promoting development of coronary collaterals in patients with atherosclerotic disease.

Resource use and quality of care for Medicare patients with acute myocardial infarction in Maryland and the District of Columbia: analysis of data from the Cooperative Cardiovascular Project.

This study sought to evaluate the quality of care rendered to Medicare beneficiaries with acute myocardial infarction by establishing the use patterns of well-proven therapies in this population. We analyzed the quality of care rendered to 4300 Medicare beneficiaries seen at Maryland and District of Columbia hospitals with retrospectively confirmed acute myocardial infarction by evaluating the use of proven therapies. The proportion of patients ideal for therapies ranged from 10% for reperfusion to 100% for smoking cessation counseling. For ideal patients the following therapies were implemented: aspirin (87%), reperfusion therapy (64%), beta-blockers on discharge (60%), and smoking cessation counseling (41%). A substantial proportion of Medicare patients with acute myocardial infarction has one or more relative or absolute contraindications to standard regimens and therefore are not ideal therapeutic candidates. In the group of ideal patients, those with no therapeutic contraindications, a significant proportion do not receive these treatments.

Spontaneous and diffuse coronary artery spasm unresponsive to conventional intracoronary pharmacological therapy: A case report

We report a case of coronary artery spasm in a woman without atherosclerotic risk factors. Coronary arteries were initially normal angiographically; however, repeat angio-gram for severe chest pain revealed diffuse spasm of left circumflex system. Vasospasm did not respond to intracoronary pharmacotherapy and resulted in Q-wave myocardial infarction.

Acute Cardiac Tamponade Secondary to Congenital Factor V Deficiency

Spontaneous cardiac tamponade secondary to a congenital coagulation defect has never been reported. We report a case of acute cardiac tamponade in a patient with a known factor V deficiency. This patient presented with classic signs of acute cardiac tamponade and an enlarged cardiac silhouette. After diagnostic two-dimensional echocardiography and treatment with fresh-frozen plasma, the patient underwent emergent pericardiocentesis followed by complete pericardiectomy.

Subvalvular left ventricular outflow tract obstruction caused by "rhinonodular" calcification.

Cardiac calcification is a common problem in patients with renal failure. Calcific deposits often affect the mitral annulus, the aortic valve, and the coronary arteries. We report an atypical case of cardiac calcification obstructing the left ventricular outflow tract with minimal aortic valve calcification.