P1694Sex is not an independent predictor of ischemic outcomes or bleeding in NSTEMI patients undergoing percutaneous coronary intervention. Insights from the TAO trial

Background

There is uncertainty regarding whether female sex is an independent predictor of adverse outcomes in acute coronary syndromes (ACS).

Purpose

We sought to describe and compare ischemic and bleeding outcomes between men and women with Non–ST-segment–Elevation (NSTE) ACS enrolled in the large Treatment of Acute coronary syndromes with Otamixaban (TAO) trial in which antithrombotic treatment was standardized and a systematic invasive approach was performed.

Methods

The TAO trial randomized moderate to high-risk NSTE-ACS patients with diagnostic coronary angiography planned in the first 72 hours to heparin plus eptifibatide versus otamixaban. This post-hoc analysis describes ischemic (all-cause death, new myocardial infarction, stent thrombosis within 180 days of randomization) and bleeding outcomes (TIMI major and minor bleeding within 30 days of randomization) according to sex.

Results

Of 13,229 patients with NSTE-ACS randomized in 55 countries, 3,980 (30.1%) were female and 9,249 (69.9%) were male. Mean age was 64.8±11.0 and 60.7±11.1 years, respectively. The prevalence of diabetes (34.0% vs. 25.8%), hypertension (80.8% vs. 67.0%), and hypercholesterolemia (55.9% vs. 52.2%) was higher among women compared with men but current smoking (21.5% vs. 38.7%) and history of previous MI were more frequent in males (15.5% vs. 20.7%).

Females experienced a higher incidence of both ischemic outcomes (10.2% vs. 9.1%; OR=1.15; 95% CI, 1.01–1.30; p=0.034) and bleeding events (4.1% vs. 3.4%; OR=1.23; 95% CI, 1.02–1.49; p=0.029). Bleeding risk and CV death were particularly increased in women younger than 50 years, compared to males of the same age, at 5.5% vs. 1.4% (OR=4.00; 95% CI, 2.13–7.69; p=0.034) and 1.7% vs. 0.5% (OR=4.35; 95% CI, 1.02–20.00; p=0.02), respectively. No difference in either outcome was found between women and men between 50 and 80 years old. Above 80 years, women experienced a lower rate of bleeding (3.9% vs. 7.8%; OR=0.47; 95% CI, 0.23–0.88; p=0.024) but a similar rate of in ischemic events (16.0% vs. 17.2%; OR=0.92; 95% CI, 0.63–1.33; p=0.67).

After adjustment for age, body weight, diabetes mellitus, prior PCI, serum creatinine, presenting systolic blood pressure, elevated biomarker at presentation, heart failure, the risk of ischemic (OR=1.03; 95% CI, 0.89–1.18; p=0.71) and bleeding events (OR=1.05; 95% CI, 0.85–1.33; p=0.65) were similar between men and women.

Conclusions

In this large international randomized trial of NSTE-ACS with standardized invasive management, women (particularly those younger than 50 years) experienced higher risks of ischemic and bleeding events than men, but the difference was not sustained after adjustment. In this population, sex was not an independent predictor of adverse outcomes in NSTE-ACS. The type of ACS (NSTE-ACS) and routine invasive management in women and men may explain this absence of difference.

Acknowledgement/Funding

The TAO trial was sponsored and funded by SANOFI. The present analysis was supported by the RHU iVASC grant “#ANR-16-RHUS-00010”

Emotional stressors trigger cardiovascular events

AIMS

To describe the relation between emotional stress and cardiovascular events, and review the literature on the cardiovascular effects of emotional stress, in order to describe the relation, the underlying pathophysiology, and potential therapeutic implications.

MATERIALS AND METHODS

Targeted PUBMED searches were conducted to supplement the authors' existing database on this topic.

RESULTS

Cardiovascular events are a major cause of morbidity and mortality in the developed world. Cardiovascular events can be triggered by acute mental stress caused by events such as an earthquake, a televised high-drama soccer game, job strain or the death of a loved one. Acute mental stress increases sympathetic output, impairs endothelial function and creates a hypercoagulable state. These changes have the potential to rupture vulnerable plaque and precipitate intraluminal thrombosis, resulting in myocardial infarction or sudden death.

CONCLUSION

Therapies targeting this pathway can potentially prevent acute mental stressors from initiating plaque rupture. Limited evidence suggests that appropriately timed administration of beta-blockers, statins and aspirin might reduce the incidence of triggered myocardial infarctions. Stress management and transcendental meditation warrant further study.

"Hot" unstable angina--is it worse than subacute unstable angina? Results from the GUARANTEE Registry

BACKGROUND AND METHODS

Because time to presentation to the hospital affects time to treatment and is known to be important in acute myocardial infarction, we evaluated this variable in patients with unstable angina/non-ST segment elevation myocardial infarction (UA/NSTEMI). Among 2909 consecutive patients with UA/NSTEMI admitted to 35 hospitals in 6 geographic regions of the United States, we compared patients with acute (onset of pain <12 hours before admission) and subacute (onset >12 hours) unstable angina.

RESULTS

Patients with "hot" (acute) unstable angina presented more often to the emergency department and were subsequently admitted more often to an intensive care unit. Hospital administration of medications did not differ between the two groups, with the exception of heparin, which was paradoxically used more often in subacute patients (p<0.001). All cardiac invasive procedures were undertaken less often in the acute patients (catheterization, 41.4% vs. 58.7%, p=0.001; percutaneous coronary intervention, 11.3% vs. 21.1%, p=0.001; coronary artery bypass grafting, 5.6% vs. 12.0%, p=0.001). A greater percentage of acute patients were found to have no significant coronary artery disease at cardiac catheterization (20.1% vs. 15.0%, p=0.006). Mortality did not differ between the two groups; however, the composite endpoint of death and MI favored the acute patients (1.3% vs. 2.2%, p=0.032).

CONCLUSIONS

Contrary to our initial hypothesis, "hot" UA patients tended to be at lower risk than patients with subacute presentation, highlighting the fact that patients with UA/NSTEMI remain at high risk even after the initial 12-hour period.

Use of lipid-lowering medications at discharge in patients with acute myocardial infarction: data from the National Registry of Myocardial Infarction 3

BACKGROUND

The present study aimed to assess use of lipid-lowering medication at discharge in a current national sample of patients hospitalized with acute myocardial infarction and to evaluate factors associated with prescribing patterns.

METHODS AND RESULTS

Demographic, procedural, and discharge medication data were collected from 138 001 patients with acute myocardial infarction discharged from 1470 US hospitals participating in the National Registry of Myocardial Infarction 3 from July 1998 to June 1999. Lipid-lowering medications were part of the discharge regimen in 31. 7%. Among patients with prior history of CAD, revascularization, or diabetes, less than one half of the patients were discharged on treatment. In multivariate analysis, factors independently related to lipid-lowering use included history of hypercholesterolemia (odds ratio [OR] 4.93; 95% CI 4.79 to 5.07), cardiac catheterization during hospitalization (OR 1.29; 95% CI 1.24 to 1.34), care provided at a teaching hospital, (OR 1.26; 95% CI 1.22 to 1.32), use of ss-blocker (OR 1.43; 95% CI 1.39 to 1.48), and smoking cessation counseling (OR 1.51; 95% CI 1.44 to 1.59). Lipid-lowering medications were given less often to patients who were older (65 to 74 versus <55 years of age; OR 0.82; 95% CI 0.78 to 0.86), those with a history of hypertension (OR 0.92; 95% CI 0.89 to 0.95), and those undergoing coronary artery bypass graft surgery (OR 0.58; 95% CI 0.55 to 0.60).

CONCLUSIONS

Analysis of current practice patterns for the use of lipid-lowering medications in patients hospitalized with acute myocardial infarction reveals that a significant proportion of high-risk patients did not receive treatment at time of discharge.

Magnesium use in the treatment of acute myocardial infarction in the United States (observations from the Second National Registry of Myocardial Infarction)

The use of magnesium in patients with acute myocardial infarction (AMI) is debated, largely as a result of conflicting data from randomized controlled trials. This study evaluated the use and impact on mortality of intravenous magnesium in the treatment of patients with AMI in the United States based on data from the Second National Registry of Myocardial Infarction. Only 5.1% of 173,728 patients from 1,326 hospitals received intravenous magnesium within the first 24 hours after an AMI, and this was more common in the 59,798 patients who received thrombolytic therapy or who underwent primary percutaneous transluminal coronary angioplasty (PTCA) or coronary bypass grafting (CABG) than in the 113,930 patients who did not receive any reperfusion therapy (8.5% vs 3.4%, p <0.01). Magnesium use was associated with younger age, Q-wave AMI, congestive heart failure on admission, thrombolytic therapy, primary PTCA or CABG, ventricular tachycardia or ventricular fibrillation, and beta blocker or lidocaine use in the first 24 hours (all odds ratio > 1.2, p <0.001). Magnesium use was associated with increased mortality (odds ratio 1.25, 95% confidence interval 1.12 to 1.34) and with a higher mortality in patients without initial reperfusion therapy (20.2% vs 13.2%, p <0.0001) or who underwent primary PTCA or CABG (10.2% vs 7.3%, p = 0.002), but not in patients who received thrombolytic therapy (6.2% vs 5.9%, p = NS). Thus, magnesium is used infrequently in the treatment of AMI and may be associated with worse outcome.

Relationship of symptom-onset-to-balloon time and door-to-balloon time with mortality in patients undergoing angioplasty for acute myocardial infarction

CONTEXT

Rapid time to treatment with thrombolytic therapy is associated with lower mortality in patients with acute myocardial infarction (MI). However, data on time to primary angioplasty and its relationship to mortality are inconclusive.

OBJECTIVE

To test the hypothesis that more rapid time to reperfusion results in lower mortality in the strategy of primary angioplasty.

DESIGN

Prospective observational study of data collected from the Second National Registry of Myocardial Infarction between June 1994 and March 1998.

SETTING

A total of 661 community and tertiary care hospitals in the United States.

SUBJECTS

A cohort of 27,080 consecutive patients with acute MI associated with ST-segment elevation or left bundle-branch block who were treated with primary angioplasty.

MAIN OUTCOME MEASURE

In-hospital mortality, compared by time from acute MI symptom onset to first balloon inflation and by time from hospital arrival to first balloon inflation (door-to-balloon time).

RESULTS

Using a multivariate logistic regression model, the adjusted odds of in-hospital mortality did not increase significantly with increasing delay from MI symptom onset to first balloon inflation. However, for door-to-balloon time (median time 1 hour 56 minutes), the adjusted odds of mortality were significantly increased by 41% to 62% for patients with door-to-balloon times longer than 2 hours (for 121-150 minutes: odds ratio [OR], 1.41; 95% confidence interval [CI], 1.08-1.84; P=.01; for 151-180 minutes: OR, 1.62; 95% CI, 1.23-2.14; P<.001; and for >180 minutes: OR, 1.61; 95% CI, 1.25-2.08; P<.001).

CONCLUSIONS

The relationship in our study between increased mortality and delay in door-to-balloon time longer than 2 hours (present in nearly 50% of this cohort) suggests that physicians and health care systems should work to minimize door-to-balloon times and that door-to-balloon time should be considered when choosing a reperfusion strategy. Door-to-balloon time also appears to be a valid quality-of-care indicator. JAMA. 2000.

Evaluation of fluid collection in the pericardial sinuses and recesses: noncontrast-enhanced electron beam tomography

RATIONALE AND OBJECTIVES

To evaluate the attenuation, size, and volume of the pericardial sinuses and recesses by using electrocardiographically triggered, noncontrast-enhanced electron beam tomography (EBT) and to consider its relation with sex, age, and heart volume.

METHODS

Findings in 213 consecutive patients without known pericardial disease were studied. The patients underwent EBT scanning of the heart to evaluate coronary artery calcification. Incremental electrocardiographically triggered noncontrast images were obtained with a 100-ms exposure time and a 3-mm slice thickness. The appearance, density, and volume of the pericardial sinuses and recesses were calculated.

RESULTS

Among the 213 patients, 97.2% had at least one of the sinuses or recesses visible on EBT. The sinuses or recesses were seen with the following frequency: transverse sinus (93.9%), oblique sinus (71.8%), and superior aortic recess (51.2%). The mean attenuation and volume were 9.9 +/- 7.3 Hounsfield units (HU), 12.6 +/- 8.1 HU, and 12.6 +/- 8.7 HU, and 1.9 +/- 1.3 mL, 1.3 +/- 1.0 mL, and 0.8 +/- 0.8 mL, respectively. The total volume of the pericardial sinuses (3.3 +/- 2.2 mL) had no significant relation with the total heart volume.

CONCLUSIONS

Pericardial sinuses and recesses were frequently and well depicted on noncontrast EBT images. In patients without obvious pericardial effusion, physiological fluid collections were observed in the transverse and oblique sinuses or other recesses. Location, attenuation, and volume were helpful in the differentiation of normal pericardial sinuses from pericardial effusions and mediastinal lymph nodes.

The volume of primary angioplasty procedures and survival after acute myocardial infarction. National Registry of Myocardial Infarction 2 Investigators

BACKGROUND

There is an inverse relation between mortality from cardiovascular causes and the number of elective cardiac procedures (coronary angioplasty, stenting, or coronary bypass surgery) performed by individual practitioners or hospitals. However, it is not known whether patients with acute myocardial infarction fare better at centers where more patients undergo primary angioplasty or thrombolytic therapy than at centers with lower volumes.

METHODS

We analyzed data from the National Registry of Myocardial Infarction to determine the relation between the number of patients receiving reperfusion therapy (primary angioplasty or thrombolytic therapy) and subsequent in-hospital mortality. A total of 450 hospitals were divided into quartiles according to the volume of primary angioplasty. Multiple logistic-regression models were used to determine whether the volume of primary angioplasty procedures was an independent predictor of in-hospital mortality among patients undergoing this procedure. Similar analyses were performed for patients receiving thrombolytic therapy at 516 hospitals.

RESULTS

In-hospital mortality was 28 percent lower among patients who underwent primary angioplasty at hospitals with the highest volume than among those who underwent angioplasty at hospitals with the lowest volume (adjusted relative risk, 0.72; 95 percent confidence interval, 0.60 to 0.87; P<0.001). This lower rate, which represented 2.0 fewer deaths per 100 patients treated, was independent of the total volume of patients with myocardial infarction at each hospital, year of admission, and use or nonuse of adjunctive pharmacologic therapies. There was no significant relation between the volume of thrombolytic interventions and in-hospital mortality among patients who received thrombolytic therapy (7.0 percent for patients in the highest-volume hospitals vs. 6.9 percent for those in the lowest-volume hospitals, P=0.36).

CONCLUSIONS

Among hospitals in the United States that have full interventional capabilities, a higher volume of angioplasty procedures is associated with a lower mortality rate among patients undergoing primary angioplasty, but there is no association between volume and mortality for thrombolytic therapy.

Payer status and the utilization of hospital resources in acute myocardial infarction: a report from the National Registry of Myocardial Infarction 2

BACKGROUND

Prior studies have suggested that payer status may be an important determinant of medical resource utilization and outcome in acute myocardial infarction (AMI).

METHODS

A national cohort of 332,221 patients with AMI enrolled from June 1994 to July 1996 were compared within 5 payer groups to ascertain the influence of payer status on hospital resource allocation for AMI in the United States.

RESULTS

Medicare comprised the largest proportion (56%), followed by commercial insurance (25%), health maintenance organization (HMO) (10%), uninsured (6%), and Medicaid (3%). Compared with commercially insured patients, Medicare and Medicaid patients received fewer reperfusion therapies, underwent fewer invasive cardiac procedures, and had longer hospitalizations. After adjusting for differences in clinical characteristics, Medicare recipients were as likely as commercially insured patients to receive acute reperfusion therapies or any invasive cardiac procedure. Uninsured and HMO patients tended to utilize hospital resources with intermediate frequency. Medicare recipients aged 65 years or older and the HMO group had similar hospital mortality rates compared with the commercial group (odds ratio [OR], 1.07; 95% confidence interval [CI], 0.96-1.20 and OR, 0.93; 95% CI, 0.83-1.04, respectively), but Medicaid and uninsured groups had higher hospital mortality rates compared with the commercial group (OR, 1.30; 95% CI, 1.14-1.48 and OR, 1.29; 95% CI, 1.12-1.48, respectively).

CONCLUSION

This report suggests significant variation by payer status in the management of AMI throughout the United States, but no important differences in mortality among the 3 largest payer groups.

Trends in acute myocardial infarction management: use of the National Registry ofMyocardial Infarction in quality improvement

Cardiovascular disease, including acute myocardial infarction (AMI), is the leading cause of death in the United States and was the primary disease category among hospital discharges in 1996. Efforts to improve hospital care of patients with AMI should be measured and assessed routinely for appropriateness of care and improvement of medical staff performance. The National Registry of Myocardial Infarction (NRMI), an observational Phase IV study, has enrolled > 1 million AMI patients since 1990, and is now in its third phase. NRMI 3 collects patient data and facilitates the measurement of improvement in care and outcomes, while allowing participating institutions to benchmark their performance against national, state, and like-hospital data. Three measures from NRMI 3 are accepted for the Joint Commission on Accreditation of Healthcare Organizations' ORYX initiative: (1) aspirin use within 24 hours of AMI diagnosis; (2) door-to-drug time for fibrinolysis; and (3) no initial reperfusion strategy given to eligible patients.

Association Between Body Weight and In-Hospital Clinical Outcome Following Thrombolytic Therapy: A Report from the National Registry of Myocardial Infarction

Background: In epidemiologic studies, excessive body weight, independent of other risk factors, portends a poor prognosis among patients with coronary artery disease experiencing acute myocardial infarction (MI). At least one recent study has suggested that patients of excessive body weight when receiving thrombolytic therapy are often under-dosed, potentially reducing early coronary arterial patency and adversely affecting in-hospital clinical outcome. Concern has also been raised that body weight may influence treatment utilization, delays, and complication rates. Despite these concerns, the association between body weight and patient outcome following coronary thrombolysis has received limited attention. Methods/Results: Demographic, procedural, and outcome data from patients with MI were collected at 1073 United States hospitals participating in The National Registry of Myocardial Infarction from 1990 through 1994. Among 350,755 patients with MI enrolled, 87,688 (25.1%) were treated with tissue plasminogen activator (t-PA). Divided into body weight tertiles, 23.5% of patients were less than 70 kg (low weight), 36.8% were 70-85 kg (moderate weight), and 37.5% were greater than 85 kg (high weight). Patients of low weight were older (p < 0.001), received treatment later (p < 0.001), and were less likely to undergo cardiac catheterization, coronary angioplasty, or bypass surgery (p < 0.001) than moderate- or high-weight patients. Low-weight patients also experienced minor bleeding, major bleeding, recurrent MI, and death more often (p < 0.001). Adjusted for age, low body weight was independently associated with in-hospital mortality. Despite receiving a lower dose of t-PA per kg body weight, high-weight patients had a low incidence of cardiogenic shock, recurrent MI, death, and hemorrhagic complications.When high-weight women and men were compared, several interesting observations emerged. Mortality was increased twofold in women (6.8% vs. 3.0; p < 0.001), even adjusting for their older age. Despite being at increased risk, women were less likely than their male counterparts to undergo cardiac catheterization (p = 0.001) or bypass surgery (p = 0.008). Conclusions: The National Registry of Myocardial Infarction provides a unique resource for assessing health care trends in the United States. Our findings suggest that low body weight is associated with increased in-hospital morbidity and mortality. They also suggest that current dosing strategies for t-PA administration are probably adequate for high-weight patients. The excessive mortality and limited use of in-hospital interventions among high-weight women deserve further study to address gender-related differences in disease processes, as well as potential bias or discrimination.

Hospital Protocols and Policies that may Delay Early Identification and Thrombolytic Therapy of Acute Myocardial Infarction Patients

Despite the compelling relationship between early treatment and outcome from reperfusion therapy in patients with acute myocardial infarction, significant delays in early treatment are imposed by the patient, prehospital systems, and hospital processes and protocols used in the identification and treatment of patients with myocardial infarction. A survey instrument designed to determine the prevalence of hospital policies and protocols that might delay or expedite treatment with thrombolytic therapy in patients with acute myocardial infarction was completed by 524 hospital participating in the National Registry for Myocardial Infarction (NRMI). Participating hospitals had treated 17,646 patients with tissue plasminogen activator. The door to drug time for the entire population of patients treated at each hospital was available. Door to drug times were compared between those hospitals that had a positive response to a policy and those that had a negative response to that policy. Among respondent hospitals, thrombolysis was excluded by protocol in 34.4% for age above 75 and in 55% for presentation after 6 hours of chest pain onset. Furthermore, 29.4% of hospitals required routine laboratory testing other than electrocardiography (ECG), including chest x-ray, prior to determination of eligibility for thrombolysis. Door to drug times were shorter in those hospitals with prehospital 12-lead ECG availability, assessment of the 12-lead ECG by the emergency department nurse and physician as soon as it was available, and initiation of thrombolysis by the emergency physician (in patients with clear-cut ST elevation myocardial infarction) without bedside cardiology consultation. Door to drug times were longer in those hospitals in which predecision laboratory results were required, written informed consent was mandated, and drug was initiated in the cardiac intensive care unit rather than in the emergency department itself. Door to drug times were not significantly different in those hospitals with a designated chest pain center compared with those operating under a focused patient care protocol. We conclude that the earliest possible hospital treatment of acute myocardial infarction patients may be precluded by multiple components of emergency department policies and process, many of them inappropriate for safe, efficient, and effective identification and management of these patients.

Reperfusion therapy in patients with acute myocardial infarction and prior coronary artery bypass graft surgery (National Registry of Myocardial Infarction-2)

We reviewed data from the National Registry of Myocardial Infarction-2 to determine the differences in characteristics and outcomes in patients with acute myocardial infarction (AMI) who have undergone previous coronary artery bypass grafting (CABG), and those who have not, and between post-CABG patients who were treated with alteplase (recombinant tissue-type plasminogen activator [rt-PA]) and those who were treated with primary percutaneous transluminal coronary angioplasty (PTCA). Demographic, therapeutic, and outcome data from patients with AMI were collected at > 1,000 hospitals in the United States in collaboration with National Registry of Myocardial Infarction-2. Of the 45,925 patients receiving reperfusion therapy, 2,544 of the 39,574 treated with rt-PA (6.4%) had a history of CABG, and 375 of the 6,351 treated with primary PTCA (5.9%) had a history of CABG. Patients with a history of CABG were older, more likely to be men, and had more comorbidities, but prior CABG was still an independent predictor of mortality after multivariate regression analysis (odds ratio 1.23; 95% confidence interval 1.05 to 1.44). Among the post-CABG patients who received rT-PA or underwent PTCA, there was no significant difference in in-hospital mortality rate or the combined end point of death and nonfatal stroke. Thus, (1) prior CABG is an independent predictor of mortality, and (2) for post-CABG patients with AMI who are not in shock and who are lytic-eligible, reperfusion therapy with rt-PA and PTCA result in similar outcomes with regard to in-hospital mortality and the combined end point of death and nonfatal stroke.

The association between the on-site availability of cardiac procedures and the utilization of those services for acute myocardial infarction by payer group. The National Registry of Myocardial Infarction 2 Investigators

BACKGROUND

Prior studies have suggested that in-hospital availability may be an important determinant for the use of invasive cardiac services; however, whether this association is influenced by payer status remains unclear.

HYPOTHESIS

The interaction of payer status and the on-site availability of coronary arteriography is associated with increased utilization of this procedure.

METHODS

In-hospital availability and utilization of coronary arteriography was ascertained in 275,046 patients with acute myocardial infarction (AMI) enrolled in the National Registry of Myocardial Infarction 2 from June 1994 to April 1996. Logistic regression analyses were performed to determine the association between the on-site availability of cardiac catheterization at the initial hospital and subsequent utilization of coronary arteriography. Similar analyses were performed within Medicare, Medicaid, Commercial, Health Maintenance Organization (HMO), and Uninsured payer groups.

RESULTS

Patients initially admitted to hospitals having on-site cardiac catheterization facilities were almost twice as likely to receive coronary arteriography as patients admitted to hospitals without such facilities and later transferred out [un-adjusted odds ratio (OR) = 1.69, 95% confidence interval (CI) 1.66-1.73, p < 0.0001; adjusted OR = 2.08, 95% CI 2.01-2.15, p < 0.0001]. Furthermore, this relationship of increased utilization with greater availability was evident within each payer group, but was highest among those with Commercial insurance and lowest among Medicaid recipients: [Commercial insurance (OR = 2.19, 95% CI 2.07-2.31, p < 0.0001); Uninsured (OR = 1.74, 95% CI 1.57-1.92, p < 0.0001); HMO (OR = 1.67, 95% CI 1.54-1.82, p < 0.0001); Medicare 1.60, 95% CI 1.55-1.64, p < 0.0001); Medicaid (1.46, 95% CI 1.29-1.65, p < 0.0001)].

CONCLUSIONS

Our results show a strong association between in-hospital availability and subsequent utilization of invasive cardiac procedures following AMI among all patients, but the strength of these associations varied among payer status.

Underuse and overuse of diagnostic testing for coronary artery disease in patients presenting with new-onset chest pain

PURPOSE

To determine the extent of overuse and underuse of diagnostic testing for coronary artery disease and whether the socioeconomic status, health insurance, gender, and race/ethnicity of a patient influences the use of diagnostic tests.

SUBJECTS AND METHODS

We identified patients who presented with new-onset chest pain not due to myocardial infarction at one of five Los Angeles-area hospital emergency departments between October 1994 and April 1996. Explicit criteria for diagnostic testing were developed using the RAND/University of California, Los Angeles, expert panel method. They were applied to data collected by medical record review and patient questionnaire.

RESULTS

Of the 356 patients, 181 met necessity criteria for diagnostic cardiac testing. Of these, 40 (22%) failed to receive necessary tests. Only 7 (3%) of the 215 patients who received some form of cardiac testing had tests that were judged to be inappropriate. Underuse was significantly more common in patients with only a high school education (30% vs 15% for those with some college, P = 0.02) and those without health insurance (34% vs 15% of insured patients, P = 0.01). In a multivariate logistic regression model, only the lack of a post-high school education was a significant predictor of underuse (odds ratio 2.2, 95% confidence interval 1.0 to 4.4).

CONCLUSION

Among patients with new-onset chest pain, underuse of diagnostic testing for coronary artery disease was much more common than overuse. Underuse was primarily associated with lower levels of patient education.

Intravenous three-dimensional coronary angiography using contrast enhanced electron beam computed tomography

Coronary angiography remains the diagnostic standard for establishing the presence, site, and severity of coronary artery disease (CAD). Electron beam computed tomography (EBCT), with its 3-dimensional capabilities, is an emerging technology with the potential for obtaining essentially noninvasive coronary arteriograms. The purpose of this study was to (1) test the accuracy of intravenous coronary arteriography using the EBCT to conventional coronary arteriographic images; (2) establish the inter-reader variability of this procedure; (3) determine the limitations due to location within the coronary tree; and (4) identify factors that contributed to improved image quality of the 3-dimensional EBCT angiograms. Fifty-two patients underwent both EBCT angiography and coronary angiography within 2 weeks. The coronary angiogram and the EBCT 3-dimensional images were analyzed by 2 observers blinded to the results of the other techniques. EBCT correctly identified 43 of 55 significantly stenosed arteries (sensitivity 78%), and correctly identified 118 of 130 of the nonobstructed arteries, yielding a specificity of 91% (p <0.001, chi-square analysis). The overall accuracy for EBCT angiography was 87%. Significantly more left main and anterior descending coronary arteries were adequately visualized than the circumflex and right coronary vessels (p = 0.003). Overall, 23 of 208 (11%) major epicardial vessels were noninterpretable by the blinded EBCT readers, primarily due to motion artifacts caused by cardiac and respiratory motion and poor electrocardiographic gating. The inter-reader variability was similar to that of angiography, and its high accuracy makes this a clinically useful test. This study demonstrates, by using intravenous contrast enhancement, that EBCT can clearly depict the coronary artery anatomy and can permit identification of coronary artery stenosis.

Consultation before thrombolytic therapy in acute myocardial infarction. Second National Registry of Myocardial Infarction (NRMI 2) Investigators

Among 57,398 thrombolytic recipients in the National Registry of Myocardial Infarction 2, consultation with another physician was sought in 64% before initiating lytic therapy, although presenting features were typical, rather than atypical, in most patients. Consultation significantly delayed the administration of lytic therapy and was associated with increased hospital mortality.

Impact of time to treatment with tissue plasminogen activator on morbidity and mortality following acute myocardial infarction (The second National Registry of Myocardial Infarction)

This study examines the association between time to treatment with thrombolytic therapy and hospital outcomes in patients with acute myocardial infarction (AMI) enrolled in a national registry. A total of 71,253 patients hospitalized with AMI from June 1994 to July 1996 who received tissue plasminogen activator (t-PA) therapy in 1,474 United States hospitals were studied. In this study sample, approximately 39% of patients presented to participating hospitals within 2 hours of acute symptom onset and received t-PA; 36% were treated within 2.1 to 4 hours, 12% between 4.1 to 6 hours, and the remaining 13% thereafter. After controlling for potentially confounding factors, in-hospital death rates increased progressively with increasing delays in time of administration of t-PA. The lowest risk for dying during acute hospitalization was seen for those treated with t-PA within 2 hours of acute symptoms. No significant association was seen between time of administration of t-PA and in-hospital risk of recurrent AMI, myocardial ischemia, cardiogenic shock, major bleeding episodes, or stroke and/or intracranial bleeding. The incidence of sustained ventricular arrhythmias declined with progressively longer time to administration of t-PA. The results of this multihospital observational study suggest that patients with AMI treated earlier with t-PA are significantly more likely to survive the acute hospitalization than patients treated later. These data reinforce the benefits to be gained by treatment with t-PA as soon as possible following the onset of acute ischemic symptoms, and for community-wide efforts to reduce the duration of prehospital delay in patients with acute coronary disease.

Influence of payor on use of invasive cardiac procedures and patient outcome after myocardial infarction in the United States. Participants in the National Registry of Myocardial Infarction

OBJECTIVES

We sought to determine the influence of payor status on the use and appropriateness of cardiac procedures.

BACKGROUND

The use of invasive procedures affects the cost of cardiovascular care and may be influenced by payor status.

METHODS

We compared treatment and outcomes of myocardial infarction among four payor groups: fee for service (FFS), health maintenance organization (HMO), Medicaid and uninsured. Multivariate comparison was performed on the use of invasive cardiac procedures, length of hospital stay and in-hospital mortality in 17,600 patients <65 years old enrolled in the National Registry of Myocardial Infarction from June 1994 to October 1995. To determine the appropriateness of coronary angiography, we compared its use in patients at low and high risk for cardiac events.

RESULTS

Angiography was performed in 86% of FFS, 80% of HMO, 61% of Medicaid and 75% of uninsured patients. FFS patients were more likely to undergo angiography than HMO (odds ratio [OR] 1.27, 95% confidence interval [CI] 1.13 to 1.42), Medicaid (OR 2.43, 95% CI 2.11 to 2.81) and uninsured patients (OR 1.99, 95% CI 1.76 to 2.25). Similar patterns for the use of coronary revascularization were found. Among those at low risk, FFS patients were as likely to undergo angiography as HMO patients but more likely than Medicaid and uninsured patients. For those at high risk, FFS patients were more likely to undergo angiography than patients in other payor groups. Adjusted mean length of stay (7.3 days) was similar among all payor groups, but adjusted mortality was higher in the Medicaid group (Medicaid vs. FFS: OR 1.55, 95% CI 1.19 to 2.01).

CONCLUSIONS

Payor status is associated with the use and appropriateness of invasive cardiac procedures but not length of hospital stay after myocardial infarction. The higher in-hospital mortality in the Medicaid cohort merits further study.

Learning curve in the use of the radial artery as vascular access in the performance of percutaneous transluminal coronary angioplasty

Radial artery access for coronary artery angioplasty is a cost-effective alternative to other vascular entry sites. The initial series of patients using the radial artery site for an operator without experience in using arm access for coronary artery angioplasty was evaluated. Clinical success was achieved via the radial artery in 87% of 32 lesions and 84% of 27 patients. The major feature limiting success via the arm was radial/brachial artery spasm, which occurred in 30% of cases (clinical success: 50% with spasm vs. 95% without spasm, P < 0.05). Spasm was more common in patients with peripheral vascular disease and in hypertensive patients not treated with calcium channel blockers prior to angioplasty. Coronary angioplasty via the radial artery may be successfully performed even by the interventionalist inexperienced in arm access. Vascular spasm is an important feature that limits the ability successfully to complete coronary angioplasty via the radial artery.

Observations of the treatment of women in the United States with myocardial infarction: a report from the National Registry of Myocardial Infarction-I

BACKGROUND

To determine whether there are sex differences in the demographics, treatment, and outcome of patients with acute myocardial infarction in the United States, data from the National Registry of Myocardial Infarction-I from September 1990 to September 1994 were examined.

METHODS

The National Registry of Myocardial Infarction-I is a national observational database consisting of 1234 US hospitals in which each hospital submits data from each patient with acute myocardial infarction to a central data collection center. For these analyses, the following variables were examined in 354 435 patients with acute myocardial infarction: demographics; use of medical therapy including thrombolytic agents; use of procedures including cardiac catheterization, percutaneous transluminal coronary angioplasty, and coronary artery bypass surgery; length of hospital stay; adverse events (stroke, major bleeding, or recurrent myocardial infarction); and causes of death.

RESULTS

In comparison with men, women experiencing acute myocardial infarction in the United States are older, with 55.7% older than 70 years. Women have a higher mortality rate than men even when controlled for age and die less often from arrhythmia but more often from cardiac rupture whether or not thrombolytic therapy is used. Treatment with aspirin, heparin, or beta-blockers is less frequent in women. When thrombolytic therapy is used, women are treated an average of almost 14 minutes later than men and experience a greater incidence of major bleeding. Cardiac catheterization, percutaneous transluminal coronary angioplasty, and coronary artery bypass surgery are used less often in women.

CONCLUSIONS

Observations from the National Registry of Myocardial Infarction-I document important sex differences in demographics, treatment, and outcome of patients with acute myocardial infarction in the United States.

Clinical experience with primary percutaneous transluminal coronary angioplasty compared with alteplase (recombinant tissue-type plasminogen activator) in patients with acute myocardial infarction: a report from the Second National Registry of Myocardial Infarction (NRMI-2)

OBJECTIVES

We sought to compare outcomes after primary percutaneous transluminal coronary angioplasty (PTCA) or thrombolytic therapy for acute myocardial infarction (MI).

BACKGROUND

Primary PTCA and thrombolytic therapy are alternative means of achieving reperfusion in patients with acute MI. The Second National Registry of Myocardial Infarction (NRMI-2) offers an opportunity to study the clinical experience with these modalities in a large patient group.

METHODS

Data from NRMI-2 were reviewed.

RESULTS

From June 1, 1994 through October 31, 1995, 4,939 nontransfer patients underwent primary PTCA within 12 h of symptom onset, and 24,705 patients received alteplase (recombinant tissue-type plasminogen activator [rt-PA]). When lytic-ineligible patients and patients presenting in cardiogenic shock were excluded, baseline characteristics were similar. The median time from presentation to initiation of rt-PA in the thrombolytic group was 42 min; the median time to first balloon inflation in the primary PTCA group was 111 min (p < 0.0001). In-hospital mortality was higher in patients in shock after rt-PA than after PTCA (52% vs. 32%, p < 0.0001). In-hospital mortality was the same in lytic-eligible patients not in shock: 5.4% after rt-PA and 5.2% after PTCA. The stroke rate was higher after lytic therapy (1.6% vs. 0.7% after PTCA, p < 0.0001), but the combined end point of death and nonfatal stroke was not significantly different between the two groups (6.2% after rt-PA and 5.6% after PTCA). There was no difference in the rate of reinfarction (2.9% after rt-PA and 2.5% after PTCA).

CONCLUSIONS

These findings suggest that in lytic-eligible patients not in shock, PTCA and rt-PA are comparable alternative methods of reperfusion when analyzed in terms of in-hospital mortality, mortality plus nonfatal stroke and reinfarction.

Comparison of exercise electron beam computed tomography and sestamibi in the evaluation of coronary artery disease

This blinded, single center study prospectively compares exercise electron beam computed tomography (EBCT) with stress technetium-99m (Tc-99m) sestamibi single-photon emission computed tomography (SPECT) in 33 patients undergoing coronary angiography for evaluation of chest pain. Patients undergoing routine cardiac catheterization for the diagnosis of chest pain were imaged at rest using EBCT. Patients exercised on a semi-supine ergometer, and exercise EBCT was immediately followed by injection of Tc-99m sestamibi for assessment of myocardial ischemia. At peak exercise, Tc-99m SPECT, followed immediately by nonionic contrast material, was injected intravenously to directly compare these 2 imaging techniques. Patients were reimaged with Tc-99m SPECT at rest 24 to 48 hours after stress. Exercise EBCT, which was analyzed using a global ejection fraction measure, had a sensitivity of 81% and a specificity of 76%, compared with angiography. Using the development of a new regional wall motion abnormality as evidence of obstructive coronary artery disease (CAD), EBCT yielded a specificity of 100% and a sensitivity of 88%. Reversible perfusion defects identified by SPECT, as evidence of obstructive CAD, revealed a sensitivity of 75% and a specificity of 71%. The specificity of regional wall motion analysis by EBCT was significantly better than SPECT (p <0.01) in this population. This study demonstrates regional wall motion assessed by EBCT to be as sensitive and more specific than SPECT myocardial perfusion imaging in identifying obstructive CAD as defined by angiography.

TACHY: an expert system for the management of supraventricular tachycardia in the elderly

PURPOSE

Many physicians find the management of supraventricular tachyarrhythmia (SVT) in the elderly complex and challenging. With the use of artificial intelligence theory, we developed an interactive computer expert system, TACHY, to recommend therapies and warn physicians of potential therapeutic side effects.

METHODS

We developed a knowledge base that stores guidelines for the management of SVT in the elderly. After the diagnosis of current SVT was input into the computer, TACHY generated a list of therapeutic options as hypotheses. TACHY then prompted the user to provide current patient-specific clinical information, and the optimal therapeutic option was then selected. Potential therapeutic side effects were also displayed. TACHY was tested in a retrospective and a prospective study. The retrospective study, comprising 96 patients with 126 episodes of SVT, was performed to determine the concordance of therapy between TACHY and cardiologists. A prospective study in 18 patients with 26 episodes of SVT was also performed to validate TACHY's recommendations in restoring sinus rhythm.

RESULTS

In the retrospective study the concordance between TACHY and the cardiologist's first therapeutic option was 95.9% (121 of 126 episodes). In the prospective study sinus rhythm was restored in 18 (69%) of 26 episodes of SVT by the first therapeutic option recommended by TACHY. In the remaining eight episodes use of the second or third suggestion of TACHY was successful in controlling the ventricular response to SVT. No adverse reaction to the therapeutic options suggested by TACHY occurred.

CONCLUSION

TACHY, a knowledge-based computer expert system that simulates human decision making, produced promising results in the management of SVT in the elderly.

Underuse of coronary revascularization procedures: application of a clinical method

OBJECTIVES

Our main objective was to apply a new method to determine whether coronary revascularization procedures are underused, especially among African-Americans and uninsured patients.

BACKGROUND

Although overuse of revascularization procedures has been studied, underuse as defined clinically has not been examined before.

METHODS

The study was conducted at four public and two academically affiliated private hospitals in Los Angeles; 671 patients who underwent coronary angiography between June 1, 1990 and September 30, 1991 and met explicit clinical criteria for coronary revascularization were included. The main outcome measure was the proportion of patients undergoing an indicated procedure within 12 months (ascertained by medical record review and confirmed with a telephone survey). Adjusted relative odds of undergoing an indicated procedure for African-Americans and patients in public hospitals compared with whites and patients in private hospitals were calculated.

RESULTS

Overall, 75% of patients underwent a revascularization procedure. Of 424 patients requiring bypass surgery, 107 angioplasty and 140 either bypass surgery or angioplasty, 59%, 66% and 75% underwent the procedure, respectively. African-Americans were less likely than whites to undergo operation (adjusted odds ratio [OR] 0.49, p < 0.05) and angioplasty (adjusted OR 0.20, p < 0.05). Patients in public hospitals were less likely than those in private hospitals to undergo angioplasty (adjusted OR 0.10, p < 0.005).

CONCLUSIONS

Underuse of coronary revascularization procedures is measurable and occurs to a significant degree even among insured patients attending private hospitals. Underuse is especially pronounced among African-Americans and patients attending public hospitals. Future cost-containment efforts must incorporate safeguards against underuse of necessary care.

The prehospital electrocardiogram in acute myocardial infarction: is its full potential being realized? National Registry of Myocardial Infarction 2 Investigators

OBJECTIVES

This study sought to examine the management and subsequent outcomes of patients with a prehospital electrocardiogram (ECG) in a large, voluntary registry of myocardial infarction.

BACKGROUND

The prehospital ECG has been proposed as a means of rapidly identifying patients with acute myocardial infarction who might be eligible for reperfusion therapy.

METHODS

The characteristics and outcomes of patients with a prehospital ECG were compared with those without a prehospital ECG in the National Registry of Myocardial Infarction 2 data base. Included in the analysis were those patients who presented to the hospital within 12 h of an acute myocardial infarction. Excluded were patients with an in-hospital infarction, transferred-in referrals and self-transported patients.

RESULTS

Prehospital ECGs were obtained in 3,768 (5%) of 66,995 National Registry of Myocardial Infarction 2 patients meeting study criteria. Median time from myocardial infarction symptom onset until hospital arrival was longer among those having a prehospital ECG (152 vs. 91 min, p < 0.001). However, once in the hospital, the prehospital ECG group experienced a shorter median time to the initiation of either thrombolysis (30 vs. 40 min, p < 0.001) or primary angioplasty (92 vs. 115 min, p < 0.001). The prehospital ECG group was more likely to receive thrombolytic therapy (43% vs. 37%, p < 0.001) and to undergo primary angioplasty (11% vs. 7%, p < 0.001). Also, the prehospital ECG group was more likely to undergo coronary arteriography (55% vs. 40%, p < 0.001), angioplasty (24% vs. 16%, p < 0.001) or bypass surgery (10% vs. 6%, p < 0.001). The in-hospital mortality rate was 8% in patients with a prehospital ECG and 12% in those without a prehospital ECG (p < 0.001). After adjusting for baseline covariates utilizing multiple logistic regression analysis, this mortality difference remained statistically significant (odds ratio 0.83, 95% confidence interval 0.71 to 0.96, p = 0.01).

CONCLUSIONS

The prehospital ECG is infrequently utilized for diagnosing myocardial infarction, and among patients with a prehospital ECG, is associated with a longer time from symptom onset to hospital arrival. Despite these shortcomings, the prehospital ECG is a test that may potentially influence the management of patients with acute myocardial infarction through wider, faster in-hospital utilization of reperfusion strategies and greater usage of invasive procedures, factors that may possibly reduce shortterm mortality. Efforts to implement the prehospital ECG more widely and more rapidly may be indicated.

Under use of coronary angiography: application of a clinical method

OBJECTIVE

To estimate the extent of under use of coronary angiography and to determine whether women, ethnic minorities and poor and uninsured patients are less likely than their counterparts to receive necessary coronary angiography.

DESIGN

Retrospective cohort study employing chart review and patient interviews.

SETTING

Four teaching hospitals: three government owned (public) and one private university medical center in Los Angeles, California.

PATIENTS

Three hundred and fifty two patients who had a positive exercise stress test between 1 January 1990 and 30 June 1991 and met explicitly defined criteria for the necessity of coronary angiography established by a multidisciplinary expert panel.

MAIN OUTCOME MEASURES

Percentage of patients who received necessary coronary angiography within 3 and 12 months following exercise stress testing, adjusted for demographic and clinical characteristics using logistic regression.

RESULTS

Overall 43% received necessary coronary angiography within 3 months and 56% within 12 months of the stress test. Women were less likely than men to receive necessary coronary angiography. Adjusted odds ratio (AOR) 0.54, 95% confidence interval (CI) 0.34-0.90 for angiography within 3 months of the stress test; AOR 0.47, 95% CI 0.29-0.77 for angiography within 12 months of the stress test. Public hospital patients underwent necessary coronary angiography less often than private hospital patients. AOR 0.40, 95% CI 0.23-0.79 for within 3 months; AOR 0.52, 95% CI 0.30-0.91 for within 12 months.

CONCLUSIONS

Under use of coronary angiography can be measured and occurs to a significant degree. It is important to develop standards of quality to address and safeguard against under use of necessary medical care.

A composite view of cardiac rupture in the United States National Registry of Myocardial Infarction

OBJECTIVES

This study was done to determine the incidence, timing and prevalence as a cause of death from cardiac rupture in patients with acute myocardial infarction.

BACKGROUND

Several clinical trials and overview analyses have suggested that the survival benefit conferred by thrombolytic therapy may be offset by a paradoxic increase in early deaths from cardiac rupture.

METHODS

Demographic, procedural and outcome data from patients with acute myocardial infarction were collected at 1,073 United States hospitals collaborating in the United States National Registry of Myocardial Infarction.

RESULTS

Among the 350,755 patients enrolled, 122,243 received thrombolytic therapy. In-hospital mortality for the overall patient population, those not treated with thrombolytics (n = 228,512) and those given thrombolytics were 10.4%, 12.9% and 5.9%, respectively (p<0.001). Cardiogenic shock was the most common cause of death in each patient group. Although the incidence of cardiac rupture was low (<1.0%), it was responsible for 7.3%, 6.1% and 12.1%, respectively, of in-hospital deaths (p<0.001). Death from rupture occurred earlier in patients given thrombolytic therapy, with a clustering of events within 24 h of drug administration. Despite the early risk, death rates were comparatively low in thrombolytic-treated patients on each of the first 30 days. By multivariable analysis, thrombolytics, prior myocardial infarction, advancing age, female gender and intravenous beta-blocker use were independently associated with cardiac rupture.

CONCLUSIONS

This large registry experience, including over 350,000 patients with myocardial infarction, suggests that thrombolytic therapy accelerates cardiac rupture, typically to within 24 to 48 h of treatment. The possibility that rupture represents an early hemorrhagic complication of thrombolytic therapy should be investigated.

Subclavian vein anatomic subtypes defined by digital cinefluroscopic venography prior to permanent pacemaker lead insertion

Digital cinefluoroscopic venography of the subclavian vein was performed in 26 consecutive patients. The optimal stored image of the anticipated venipuncture site was magnified, road mapped, and used to compare with fluoroscopic-guided venipuncture. Two anatomic subtypes for both subclavian veins were observed. For the left subclavian vein, a gradual curve was seen most often (57%), while the remainder (43%) exhibited an "s"-shaped curve. For the right subclavian, a gradual curve was observed most frequently (60%) while an acute 90 degrees angle was noted in the remainder (40%). The "s"-shaped curve in the left subclavian vein necessitated redirection of the needle site both laterally and cranially. In three or 12% of patients venography showed either subclavian thrombosis or a persistent left superior vena cava and lead insertion was moved to the opposite side. Successful venipuncture and subsequent cannulation of the subclavian vein was achieved with the first or second passage of the needle in 22 or 85% of the 26 patients. Digital cinefluoroscopic venography appears to be both safe and rapid and may facilitate insertion of permanent pacemaker leads into the subclavian vein.

Racial differences in coronary calcium prevalence among high-risk adults

A total of 1,461 asymptomatic high-risk adult subjects were studied with digital subtraction fluoroscopy and conventional cinefluoroscopy to detect coronary calcium. Ethnicity and risk factor data were recorded. No subject had a history or electrocardiographic evidence of prior myocardial infarction. The prevalence of coronary calcium by digital subtraction fluoroscopy was high (58%). Substantial ethnic differences in prevalence were noted: 36% of African American subjects, 60% of Caucasian subjects, and 60% of Asian American subjects had definite radiographic evidence of coronary calcium. The difference in prevalence between African American and other subjects was significant (p < 0.0001) by chi-square test for all 3 races. These differences persisted in the unsubtracted cinefluoroscopic images (p < 0.0001) and after controlling for age, gender, and other risk factors (p = 0.003). After 20 +/- 11 months of follow-up, African Americans had more coronary artery disease events (13%) than Caucasians (6%) or Asian Americans (5%) (p = 0.04). Thus, African Americans have a significantly lower prevalence of coronary calcium than do Caucasians or Asian Americans. Based on the follow-up results, these differences in prevalence are not explained by differences in coronary artery disease risk.

Treatment of myocardial infarction in the United States (1990 to 1993). Observations from the National Registry of Myocardial Infarction

BACKGROUND

Multiple clinical trials have provided guidelines for the treatment of myocardial infarction, but there is little documentation as to how consistently their recommendations are being implemented in clinical practice.

METHODS AND RESULTS

Demographic, procedural, and outcome data from patients with acute myocardial infarction were collected at 1073 US hospitals collaborating in the National Registry of Myocardial Infarction during 1990 through 1993. Registry hospitals composed 14.4% of all US hospitals and were more likely to have a coronary care unit and invasive cardiac facilities than nonregistry US hospitals. Among 240,989 patients with myocardial infarction enrolled, 84,477 (35.1%) received thrombolytic therapy. Thrombolytic recipients were younger, more likely to be male, presented sooner after onset of symptoms, and were more likely to have localizing ECG changes. Among the 60,430 patients treated with recombinant tissue-type plasminogen activator (rTPA), 23.2% received it in the coronary care unit rather than in the emergency department. Elapsed time from hospital presentation to starting rTPA averaged 99 minutes (median, 57 minutes). Among patients receiving thrombolytic therapy, concomitant pharmacotherapy included intravenous heparin (96.9%), aspirin (84.0%), intravenous nitroglycerin (76.0%), oral beta-blockers (36.3%), calcium channel blockers (29.5%), and intravenous beta-blockers (17.4%). Invasive procedures in thrombolytic recipients included coronary arteriography (70.7%), angioplasty (30.3%), and bypass surgery (13.3%). Trend analyses from 1990 to 1993 suggest that the time from hospital evaluation to initiating thrombolytic therapy is shortening, usage of aspirin and beta-blockers is increasing, and usage of calcium channel blockers is decreasing.

CONCLUSIONS

This large registry experience suggests that management of myocardial infarction in the United States does not yet conform to many of the recent clinical trial recommendations. Thrombolytic therapy is underused, particularly in the elderly and late presenters. Although emerging trends toward more appropriate treatment are evident, hospital delay time in initiating thrombolytic therapy remains long, aspirin and beta-blockers appear to be underused, and calcium channel blockers and invasive procedures appear to be overused.

Prognostic significance of cardiac cinefluoroscopy for coronary calcific deposits in asymptomatic high risk subjects

OBJECTIVES

This research investigated the prognostic significance of radiographically detectable coronary calcific deposits.

BACKGROUND

Coronary calcific deposits are almost always associated with coronary atherosclerosis. We investigated the association between fluoroscopically determined coronary calcium and coronary heart disease end points at 1 year of follow-up.

METHODS

This prospective population-based cohort study was conducted in the suburbs of Los Angeles. Fourteen hundred sixty-one asymptomatic adults with an estimated > or = 10% risk of having a coronary heart disease event within 8 years underwent cardiac cinefluoroscopy for assessment of coronary calcium at initiation of the study. Clinical status including angina, documented myocardial infarction, myocardial revascularization and death from coronary heart disease were determined after 1 year.

RESULTS

The prevalence of calcific deposits was high (47%). A follow-up examination at 1 year was successfully completed in 99.9% of subjects. Six subjects (0.4%) had died from coronary heart disease and 9 (0.6%) had had a nonfatal myocardial infarction. Thirty-seven subjects (2.5%) reported angina pectoris, and 13 (0.9%) had undergone myocardial revascularization. Fifty-three subjects had at least one event during the 1-year period. Radiographically detectable calcium was associated with the presence of at least one of these end points, with a risk ratio of 2.7 (confidence limits 1.4, 4.6). The presence of coronary calcium was an independent predictor of at least one end point when controlling for age, gender and risk factors. However, three deaths due to coronary heart disease and two nonfatal myocardial infarctions occurred in subjects without detectable coronary calcium.

CONCLUSIONS

The presence of coronary calcific deposits incurs an increased risk of coronary heart disease events in asymptomatic high risk subjects at 1 year. This increased risk is independent of that incurred by standard risk factors.

Prevalence of fluoroscopic coronary calcific deposits in high-risk asymptomatic persons

Coronary calcific deposits are always associated with coronary atherosclerosis. Sensitive radiographic technology can detect coronary calcium before atherosclerosis becomes symptomatic. A total of 1461 asymptomatic high-risk adult subjects were studied with digital subtraction fluoroscopy to detect coronary calcium. Risk factor data were recorded including age, sex, family history, smoking history, diabetes history, body mass index, systolic blood pressure, left ventricular hypertrophy on ECG, total serum cholesterol level, high-density lipoprotein (HDL) cholesterol, and total cholesterol/HDL ratio. Digital subtraction fluoroscopy in the left anterior oblique projection was performed in all subjects. The prevalence of calcific deposits in at least one major coronary artery was high (58.3%). Eleven percent had coronary calcium in all three major arteries. Multivariate logistic regression analysis showed significant correlations (p < 0.05) between the prevalence of coronary calcium and age, smoking history (relative risk = 1.30), diabetes history (relative risk = 1.24), and family history (relative risk = 1.26). In older subjects (at least 65 years of age), smoking and serum lipoproteins assumed greater importance as contributors to coronary calcium, whereas in younger subjects a history of diabetes was more significant. Coronary calcific deposits are prevalent in high-risk asymptomatic subjects. Their occurrence is closely related to most known risk factors.

Dose-response of chronic beta-blocker treatment in heart failure from either idiopathic dilated or ischemic cardiomyopathy. Bucindolol Investigators

BACKGROUND

Small-scale clinical investigations have demonstrated that single doses of beta-blocking agents can improve left ventricular function in heart failure from idiopathic dilated cardiomyopathy (IDC). The purpose of this multicenter clinical trial was to determine the dose-effect characteristics of beta-blockade in a heart failure population that includes ischemic dilated cardiomyopathy (ISCD).

METHODS AND RESULTS

Bucindolol is a nonselective beta-blocking agent with mild vasodilatory properties. One hundred forty-one subjects with class II or III heart failure, left ventricular ejection fraction (LVEF) < or = 0.40, and background therapy of angiotensin-converting enzyme inhibitors, digoxin, and diuretics were given an initial challenge dose of bucindolol 12.5 mg. One hundred thirty-nine subjects (99 with IDC, 40 with ISCDC) tolerated challenge and were randomized to treatment with placebo or bucindolol 12.5 mg/d (low dose), 50 mg/d (medium dose), or 200 mg/d (high dose). At the end of 12 weeks, left ventricular function and other parameters were measured and compared with baseline values. There was a dose-related improvement in left ventricular function in bucindolol-treated subjects. In the high-dose bucindolol group, radionuclide-measured LVEF improved by 7.8 EF units (%) compared with 1.8 units in the placebo group (P < .05), and compared with the placebo group, a greater percentage of subjects had an increase in LVEF by > or = 5 units. In contrast, all three bucindolol doses prevented deterioration of myocardial function as defined by an LVEF decline of > or = 5 units.

CONCLUSIONS

In heart failure from systolic dysfunction, beta-blockade with bucindolol produces a dose-related improvement in and prevents deterioration of left ventricular function.

Effects of exercise test results on physician perceptions of coronary artery disease probability using a threshold analysis

The incremental diagnostic value of exercise electrocardiographic testing compared with clinical data alone in the diagnosis of coronary artery disease (CAD) was found to be of limited value in a previous study. That study used a computer algorithm for diagnosing disease. Thus, the strict use of the results apply only to computerized disease diagnosis rather than physicians' diagnoses. The aim of the present study was to determine whether exercise test data improve a physician's ability to detect the presence or absence of CAD and 3-vessel or left main CAD, and whether the data effect the decision to perform angiography. The study sample comprised a data base of 312 patients whose clinical data, exercise test results and coronary anatomy were known. Individual cases were presented to 8 cardiologists with and without exercise data. The cardiologists provided estimates of disease probability and were asked whether they would request coronary angiography. Receiver-operating characteristic curves and goodness-of-fit analysis showed better discrimination and calibration of the estimates for the presence of CAD and 3-vessel/left main CAD after exercise test results were known. Individualized probability thresholds for deciding whether to request angiography were determined for each physician. Forty-three percent of patients crossed greater than or equal to 1 threshold, with 64% of the crossings in the correct direction. For estimating the presence of any CAD, 84% of crossings from below to above a threshold were correct, whereas only 36% from above to below were correct. For 3-vessel/left main CAD, 36% of crossings from below to above a threshold were correct, whereas 88% from above to below were correct.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of patients with chest pain and nondiagnostic ECG using thallium-201 myocardial planar imaging and technetium-99m first-pass radionuclide angiography in the emergency department

STUDY OBJECTIVE

The purpose of this study was to determine if thallium-201 myocardial planar imaging and technetium-99m first-pass radionuclide angiography, performed in the emergency department, could predict which patients with acute chest pain and nondiagnostic ECGs were more likely to have an acute myocardial infarction (AMI).

DESIGN

Retrospective analysis.

SETTING

Urban, county ED.

TYPE OF PARTICIPANTS

Convenience sample of 47 patients with acute chest pain suggestive of myocardial ischemia and nondiagnostic ECG.

INTERVENTIONS

Thallium-201 myocardial imaging and technetium-99m first-pass radionuclide angiography in the ED.

MEASUREMENTS AND MAIN RESULTS

Four patients had an AMI (ie, CK-MB greater than or equal to 6% total CK). The combined scans had a sensitivity of 75%, (95% confidence interval [Cl], 19-99%), a specificity of 42% (95% CI, 27-58%), an accuracy of 45% (95% CI, 19-99%), a positive predictive value of 11% (95% CI, 2-29%), and a negative predictive value of 95% (95% CI, 75-100%) in predicting AMI.

CONCLUSION

Thallium-201 myocardial planar imaging and technetium-99m first-pass radionuclide angiography performed in the ED do not appear to be useful in determining which patients with acute chest pain and nondiagnostic ECG are likely to have an AMI.

Use of transesophageal echocardiography during thrombolysis with tissue plasminogen activator of a thrombosed prosthetic mitral valve

Inadequate anticoagulation in patients with mechanical prosthetic heart valves can result in a significant incidence of thromboembolic complications. An even more life-threatening complication is massive thrombosis of the valve itself. Thrombolytic therapy was given to a moribund 22-year-old woman with intractable heart failure caused by a thrombosed St. Jude prosthetic mitral valve (St. Jude Medical, Inc., St. Paul, Minn.). Although this form of therapy has been used before, this is the first report of a case in which transesophageal echocardiography was performed during thrombolytic therapy to continually record successful thrombolysis of the clotted prosthetic valve. Serial imaging during thrombolysis displayed progressive dissolution of the thrombus and progressive improvement in valve function. Transesophageal echocardiography is helpful in the diagnosis of prosthetic valve thrombosis and has the ability to monitor continually the effect of treatment with thrombolysis. Although thrombolytic therapy with recombinant tissue plasminogen activator is effective in treating prosthetic valve thrombosis, it carries a high risk for serious thromboembolic complications and thus should be reserved for critically ill patients who are too sick to undergo immediate surgery.

Intravascular ultrasound imaging of an acute dissecting aortic aneurysm: a case report

A case of acute dissecting aortic aneurysm is described in which intravascular ultrasonography was used at the time of aortography to produce real-time, 360 degree cross-sectional images of the aorta. The transmural vessel morphology visualized by this new catheter-based technology allowed confirmation of the diagnosis and identification of distal extension to the aortic bifurcation. The case demonstrates the unique potential of this modality in diagnosis and possible therapy in vascular diseases.

Relationship between right atrial and mixed venous oxygen saturation and heart rate during exercise in normal subjects and patients with cardiac disease

An ideal sensing variable for use in rate responsive pacemakers should measure a physiological parameter that closely correlates with heart rate during various activities in a diverse group of subjects. Nineteen patients, 12 normal and 7 patients with heart disease, were studied to assess the relationship between mixed venous oxygen saturation and heart rate. In patients with heart disease right atrial oxygen saturation and heart rate were also compared. Each subject underwent pulmonary artery catheterization and performed seated cycle ergometer exercise. Gas exchange and heart rate were measured continuously and blood sampled at frequent intervals. Normal patients were studied at rest and during steady-state exercise (mean work rate 149 watts). Patients were studied at rest, steady-state exercise (mean work rate 37 watts), and during incremental exercise (5-10 watts/min) to tolerance. There were 248 paired right atrial or mixed venous oxygen saturation/heart rate observations obtained. Changes in mixed venous oxygen saturation and heart rate were not substantially altered by fitness or cardiac disease. Rate responsive pacemakers sensing changes in oxygen saturation may be a superior sensing variable for both normal and patients with heart disease.

Verapamil induced ventricular hypertrophy in conscious dogs

Verapamil is used clinically in the treatment of various cardiac diseases including hypertrophic cardiomyopathy. Its long term effects on ventricular mass are not well known. In 11 conscious dogs heart rate, aortic and left ventricular pressures, cardiac output, a methoxamine induced stress ventricular function test and left ventriculography were performed. These variables were measured prior to and following a mean 7.2 month infusion of verapamil at 0.005 or 0.01 mg.kg-1.min-1 using a subcutaneously implanted pump. Resting haemodynamic variables and left ventricular ejection fraction [60(SD 6) v 55(6)%] were unchanged between baseline and chronic verapamil studies, but the slope of the methoxamine induced stress ventricular function test decreased from 3.9(0.8) to 2.1 (1.3). After verapamil was discontinued the mean slope of the stress ventricular function test returned to the baseline 4.0(1.7). Total ventricular weight increased 22% from 176.1(17.5) g.m-2 in controls to 215.6(29.5) g.m-2 (p less than 0.01) in the verapamil animals. The right ventricular weight increased 25% from 46(5.9) to 57.6(9.1) g.m-2 (p less than 0.01); the septum weight increased 26% from 42.5(4.1) to 53.7(7.2) g.m-2 (p less than 0.001); and the left ventricular free wall weight increased 19% from 87.4(9.8) to 103.9(15.7) g.m-2 (p less than 0.01). The increase in ventricular weights was not due to fibrosis or oedema since hydroxyproline contents and wet/dry ratios were not increased. In conclusion, a chronic infusion of verapamil in conscious dogs caused no change in resting haemodynamic variables but produced reversible depression of stress ventricular function and biventricular and septal hypertrophy.

Direct cocaine cardiotoxicity demonstrated by endomyocardial biopsy

The morbidity and mortality associated with cocaine abuse has markedly increased in recent years. Although several articles indicate a possible connection of cocaine with coronary spasm and acute myocardial infarction, this study in seven patients with a history of cocaine abuse, who underwent endomyocardial biopsy, suggests that cocaine may cause direct toxicity to the myocardium. Myocardial specimens from five of seven patients showed multifocal myocyte necrosis, of which two specimens revealed focal myocarditis, while three specimens had changes consistent with dilated cardiomyopathy. Ultrastructurally, extensive loss of myofibrils and sarcoplasmic vacuolization were observed. It is postulated that the pathogenesis of acute cocaine-induced toxicity is direct destruction of myofibrils resulting in myocyte necrosis and that these changes may or may not be associated with interstitial inflammatory cell infiltrates. Long-term abuse of cocaine may lead to interstitial fibrosis and eventually congestive heart failure.

Inadvertent Swan-Ganz catheter placement in the left pericardiophrenic vein

Placement of flow-directed Swan-Ganz catheters without fluoroscopic guidance occasionally results in placement in positions other than the pulmonary artery. In the case presented, the inadvertent placement of such a catheter into the left pericardiophrenic vein was probably facilitated by distortion of the right heart and systemic venous anatomy.

Chest trauma and subvalvular left ventricular aneurysms

Two patients were discovered to have pulsatile saccular lesions at the base of the left ventricle and mitral regurgitation following blunt trauma to the chest. These aneurysms resembled annular subvalvular aneurysms which have previously been reported as congenital defects in African blacks and as acquired lesions following endocarditis or mitral valve replacement. The first patient had two aneurysms, while the second had an aneurysm in continuity with a traumatic ventricular septal defect. These aneurysms were detected by echocardiography and magnetic resonance imaging and should be sought in patients who develop valvar regurgitation following chest trauma.

Physiological importance of different atrioventricular intervals to improved exercise performance in patients with dual chamber pacemakers

To determine the importance of different atrioventricular intervals during exercise in patients with dual chamber pacemakers, seven patients with complete heart block and sinus rhythm were exercised in different pacing modes and atrioventricular intervals: (a) ventricular inhibited (VVI) pacing with no synchronous atrial augmentation or rate responsiveness; (b) atrial synchronous ventricular or DDD pacing with a short mean (SD) atrioventricular interval of 66 (4) ms; and (c) DDD pacing with a long atrioventricular interval of 168 (12) ms. Pacing with a short or long atrioventricular interval gave similar maximum heart rates, oxygen uptake at the anaerobic threshold, end tidal pressure of carbon dioxide or oxygen pulse (a measure of stroke volume). Pacing with either a short or long atrioventricular interval produced a significantly higher oxygen consumption and anaerobic threshold and less lactate production than VVI pacing. During exercise a short atrioventricular interval does not provide a better cardiopulmonary performance than a long atrioventricular interval.

Simultaneous technetium-99m MIBI angiography and myocardial perfusion imaging

Resting first-pass radionuclide angiography (FPRNA) was performed with the myocardial perfusion agent technetium-99m MIBI. In 27 patients, it was compared with technetium-99m diethylenetriamine pentaacetic acid FPRNA. A significant correlation was present in left (r = 0.93, p less than 0.001) as well as right (r = 0.92, p less than 0.001) ventricular ejection fraction measured with both radiopharmaceuticals. In 13 patients, MIBI derived segmental wall motion was compared with contrast ventriculography. A high correlation was present (p less than 0.001), and qualitative agreement was found in 38/52 segments. In 19 patients with myocardial infarction a significant correlation was present between MIBI segmental wall motion and perfusion scores (p less than 0.001). In ten patients with a history of myocardial infarction, 18 myocardial segments demonstrated diseased coronary vessels and impaired wall motion at contrast angiography. These segments were all identified by the MIBI wall motion and perfusion study. We conclude that MIBI is a promising agent for simultaneous evaluation of cardiac function and myocardial perfusion at rest.

Physiological benefits of a pacemaker with dual chamber pacing at low heart rates and single chamber rate responsive pacing during exercise

Dual chamber rate responsive pacing may be an ideal mode but may result in high current drain and premature battery depletion. To minimize battery drain during exercise, this study compared a combination pacing mode of DDD and ventricular rate responsive pacing (VVIR). Nine patients were studied who had complete heart block, sinus rhythm, DDD pacemakers, and a reduced mean left ventricular ejection fraction of 44%. Patients were exercised in DDD, VVIR, and a combination of DDD at low heart rates and VVIR at mean heart rates over 89 bpm. Blood pressure, heart rate, exercise duration, work rate, oxygen uptake, anaerobic threshold, and oxygen pulse were measured. There was no difference in symptoms or in mean cardiopulmonary function indices including exercise duration 10.7, 10.3, 10.3 minutes; heart rate 127, 133, 136 bpm; oxygen uptake 1.4, 1.5, 1.5 L/minute; or anaerobic threshold 5.6, 5.5, 5.7 minutes (p greater than 0.05) in any mode. A pacemaker that provides atrioventricular synchrony at low heart rates with ventricular rate responsiveness at high heart rates may be an alternative mode for some patients.

Light chain cardiomyopathy associated with small-vessel disease

Intramyocardial small-vessel disease associated with systemic light chain deposition is a rare condition that may occur in patients with monoclonal plasma cell proliferation. This article describes a 39-year-old woman who had experienced several episodes of subendocardial myocardial infarction and was found to have plasma cell dyscrasia. Endomyocardial biopsy revealed kappa light chain deposits along the sarcolemmal and vascular basement membranes, the latter of which resulted in vascular occlusion and myocardial infarction. Postmortem examination showed polyvisceral deposition of kappa light chains. This rare complication of plasma cell proliferative process has a poor prognosis.