Six year follow up of a consecutive series of patients presenting to the coronary care unit with acute chest pain: prognostic importance of the electrocardiogram

Cost effectiveness of diagnostic strategies for patients with acute, undifferentiated chest pain

OBJECTIVES

Patients presenting to hospital with acute, undifferentiated chest pain have a low, but important, risk of significant myocardial ischaemia. Potential diagnostic strategies for patients with acute, undifferentiated chest pain vary from low cost, poor effectiveness (discharging all home) to high cost, high effectiveness (admission and intensive investigation). This paper aimed to estimate the relative cost effectiveness of these strategies.

METHODS

Decision analysis modelling was used to measure the incremental cost per quality adjusted year of life (QALY) gained for five potential strategies to diagnose acute undifferentiated chest pain, compared with the next most effective strategy, or a baseline strategy of discharging all patients home without further testing.

RESULTS

Cardiac enzyme testing alone costs pound 17 432/QALY compared with discharge without testing. Adding two to six hours of observation and repeat enzyme testing costs an additional pound 18 567/QALY. Adding exercise testing to this strategy costs pound 28 553/QALY. A strategy of overnight admission, enzyme, and exercise testing has an incremental cost of pound 120 369/QALY, while a strategy consisting of overnight admission without exercise testing is subject to extended dominance. Sensitivity analysis revealed that the results are sensitive to variations in the direct costs of running each strategy and to variation in assumptions regarding the effect of diagnostic testing upon quality of life of those with non-cardiac disease.

CONCLUSION

Observation based strategies incur similar costs per QALY to presently funded interventions for coronary heart disease, while strategies requiring hospital admission may be prohibitively poor value for money. Validation of the true costs and effects of observation based strategies is essential before widespread implementation.

Ten year mortality in patients with suspected acute myocardial infarction

OBJECTIVE

To describe the 10 year mortality in patients with suspected acute myocardial infarction.

DESIGN

Follow up of all patients below 76 years of age admitted with acute chest pain to 16 coronary care units participating in the Danish verapamil infarction trial in 1979-81.

SUBJECTS

Of the 5993 patients included, 2586 had definite infarction, 402 had probable infarction, and 3005 did not have infarction.

MAIN OUTCOME MEASURES

Death and cause of death. Standardised mortality ratio (observed mortality/expected mortality in background population).

RESULTS

The estimated 10 year mortalities were 58.8%, 55.5%, and 42.8% in patients with definite, probable, and no infarction, respectively (P < 0.0001). Stratified Cox's analysis identified a hazard ratio for mortality of 1.25 (95% confidence interval 1.08 to 1.44) for probable infarction compared with no infarction and of 1.15 (1.00 to 1.32) for definite compared with probable infarction. The standardised mortality ratio in the first year was 7.1 (6.5 to 7.8) for definite infarction, 5.0 (3.6 to 6.3) for probable infarction, and 4.7 (4.2 to 5.2) for no infarction. From the second year and onwards the annual standardised mortality ratio in the three groups did not differ significantly. Cardiac causes of deaths were recorded in 89%, 84%, and 71% of the deaths in patients with definite, probable, and no infarction, respectively.

CONCLUSIONS

The 10 year mortality of patients with and without infarction is significantly higher than in the background population. Most deaths are caused by coronary heart disease, and these patients should consequently be further evaluated at the time of discharge and followed up closely.

Ten-year mortality rate among patients in whom acute myocardial infarction was not confirmed in relation to clinical history and observations during hospital stay: experiences from the Göteborg Metoprolol Trial

BACKGROUND

The majority of patients hospitalized due to suspected acute myocardial infarction (AMI) will eventually not develop infarction. Information about the long-term prognosis in this patient population is limited.

AIM

To describe the mortality during 10 years of follow-up in patients hospitalized due to an initially strong suspicion of AMI, but in whom the diagnosis of AMI could not be confirmed.

PATIENTS

All patients participating in an early intervention trial with metoprolol in suspected AMI, but in whom the diagnosis was not confirmed. Patients were included during 1976-1981.

RESULTS

In all 1395 patients were included in the study, of whom 586 did not fulfil the criteria for confirmed AMI. The overall mortality during 10 years of follow-up in this population was 26%. In a multivariate analysis considering age, sex, history of cardiovascular diseases, initial heart rate and various complications during the hospital stay, including congestive heart failure, severe ventricular arrhythmias, tachycardia, hypotension, high degree AV-block and severe chest pain, the following appeared as independent predictors of death: previous infarction (P < 0.001), age (P < 0.001), history of diabetes mellitus (P < 0.001) history of smoking (P < 0.05), history of hypertension (P < 0.05), male sex (P < 0.05), and the initial heart rate (P < 0.05).

CONCLUSION

Among patients in whom AMI was not confirmed the major risk indicators for death during 10 years of follow-up were: a history of cardiovascular diseases and smoking, age, male sex and high heart rate on admission to hospital.

Regression of ECG signs of myocardial infarction related to infarct size and left ventricular function

Quantitative and qualitative analyses of Q waves and QRS scores were performed on 69 patients during the early phase of first myocardial infarction (MI) and 6 months subsequently. The regression of ECG signs of MI were compared with the enzymatically estimated size of MI, the location of MI, and with the changes of global ejection fraction (GEF) assessed by radionuclide ventriculography. Among 57 patients with Q wave MI a complete disappearance of ECG signs of MI was found in 9 (15.7%). Patients with MI of inferior location showed a significantly higher reduction of Q waves (p < 0.001) and QRS scores (p < 0.001) than the anterior MI group. In the group of 12 patients with non Q wave MI, 11 demonstrated complete regression of MI signs. Among all Q wave and non Q wave MIs, the authors found no significant difference in the size of MI between patients with and without complete regression of ECG signs of MI. The median of the percent of change of the QRS score was significantly higher (p = 0.04) in the group of patients with improved GEFs than in the group of patients with decreased or unchanged GEFs 6 months following acute MI. The sensitivity, specificity, and predictive values for improved left ventricular function according to the change of Q waves and ECG scores were 91%, 32%, and 62%; for changes of Q waves, 81%, 40%, and 63%; and for changes of ECG scores, 91%, 36%, and 64%, respectively. In the group of patients with non Q wave MI these values were 100%, 50%, and 91% as a result of ST-T disappearance.

Feasibility, safety, and efficacy of domiciliary thrombolysis by general practitioners: Grampian region early anistreplase trial. GREAT Group

OBJECTIVE

To assess the feasibility, safety, and efficacy of domiciliary thrombolysis by general practitioners.

DESIGN

Randomised double blind parallel group trial of anistreplase 30 units intravenously and placebo given either at home or in hospital.

SETTING

29 rural practices in Grampian admitting patients to teaching hospitals in Aberdeen (average distance 36 (range 16-62) miles).

PATIENTS

311 patients with suspected acute myocardial infarction and no contraindications to thrombolytic therapy seen at home within four hours of onset of symptoms.

MAIN OUTCOME MEASURES

Time saving, adverse events, Q wave infarction, left ventricular function.

RESULTS

Anistreplase was administered at home 101 minutes after onset of symptoms, while anistreplase was given in hospital 240 minutes after onset of symptoms (median times). Adverse events after thrombolysis were infrequent and, apart from cardiac arrest, not a serious problem when they occurred in the community: seven of 13 patients were resuscitated after cardiac arrest out of hospital. By three months after trial entry the relative reduction of deaths from all causes in patients given thrombolytic therapy at home was 49% (13/163 (8.0%) v 23/148 (15.5%); difference -7.6% (95% confidence interval -14.7% to -0.4%), p = 0.04). Full thickness Q wave infarction was less common in patients with confirmed infarction receiving treatment at home (65/122 (53.3%) v 76/112 (67.9%); difference -14.6% (95% confidence interval -27.0% to -2.2%), p = 0.02).

CONCLUSIONS

General practitioners provided rapid pre-hospital coronary care of a high standard. Compared with later administration in hospital, giving anistreplase at home resulted in reduction in mortality, fewer cardiac arrests, fewer Q wave infarcts, and better left ventricular function. Benefits were most marked where thrombolytic therapy was administered within two hours of the onset of symptoms.

Long-term survival of emergency department patients with acute chest pain

To evaluate the long-term prognosis of patients with acute chest pain, prospective clinical data and long-term follow-up data (mean 30.1 +/- 9.4 months) were collected for 1,956 patients who presented to the emergency department of an urban teaching hospital with this chief complaint. During follow-up of the 1,915 patients who were discharged alive from the emergency department or hospital, there were 113 (6%) cardiovascular deaths. No differences were detected in the post-discharge cardiovascular survival rates after 3 years of experience with patients who were discharged from the emergency department with a known prior diagnosis of angina or myocardial infarction (89%) and patients who had been admitted and found to have acute myocardial infarction (85%), angina (87%), or other cardiovascular diagnoses (87%). Patients who were discharged from either the hospital or the emergency department without cardiovascular diagnoses had an excellent prognosis. Multivariate Cox regression analysis identified 5 independent correlates of cardiovascular mortality after discharge: age, prior history of coronary disease, ischemic changes on the emergency department electrocardiogram, congestive heart failure and cardiogenic shock. These findings indicate that the postdischarge cardiovascular mortality of patients with chest pain who are discharged from the emergency department with a known history of coronary disease is similar to that of admitted patients with angina or myocardial infarction. These data suggest that the same types of prognostic evaluation strategies that have been developed for admitted patients with ischemic heart disease should also be considered when such patients present to the emergency department but are not admitted.