The prognosis for patients referred with suspected acute myocardial infarction

Ten-year mortality for patients discharged after hospitalization for chest pain or other symptoms raising suspicion of acute myocardial infarction in relation to hospital discharge diagnosis

AIM

To describe the 10-year prognosis for patients discharged after hospitalization for chest pain or other symptoms giving an initial suspicion of acute myocardial infarction (AMI) in relation to the final hospital diagnosis and furthermore to compare the outcome amongst these patients with the outcome amongst a sex-, age- and community-matched control population.

METHODS

All patients who were hospitalized because of chest pain or other symptoms raising a suspicion of AMI and who were discharged alive from hospital. Patients were divided into three groups according to the final diagnosis: (1) confirmed or possible AMI, (2) confirmed or possible myocardial ischaemia and (3) other aetiology. Information on 10-year mortality was available in 3103 patients. A sex-, age- and community-matched control population (n=3221) was compared with the study population in terms of 10-year mortality. TIME OF SURVEY: 15 February 1986 to 9 November 1987.

SETTING

Sahlgrenska University Hospital.

RESULTS

Patients with confirmed or possible AMI (n=849) had a significantly higher mortality (59.4%) than patients with confirmed or possible myocardial ischaemia (n=1191) who had a mortality of 49.5% (P < 0.0001). The latter group had a higher mortality than patients with 'other aetiology' (n=1063) of whom 40.6% died (P < 0.0001). When comparing the prognosis for patients with AMI and myocardial ischaemia, there was a significant interaction with sex, with a more marked difference in women than in men. Amongst all patients, the 10-year mortality was 49.1 vs. 37.3% in the control group (P < 0.0001).

CONCLUSION

The very long term prognosis was strongly associated with diagnosis amongst patients hospitalized and discharged alive because of chest pain or other symptoms raising suspicion of AMI. The absolute mortality difference between patients who were discharged from hospital with confirmed diagnosis of AMI and those whose symptoms were considered to have other aetiology than AMI or ischaemia was nearly 20%. However, the absolute mortality difference between the patients included in the survey and a control population was only 12%.

Predictors of death during 5 years after hospital discharge among patients with a suspected acute coronary syndrome with particular emphasis on whether an infarction was developed

AIM

To describe predictors of death after hospital discharge during 5 years of follow-up in a consecutive series of patients surviving hospitalization for symptoms and signs of a confirmed or suspected acute coronary syndrome.

PATIENTS AND METHODS

All patients who between February 15, 1986 and November 9, 1987, were hospitalized at Sahlgrenska University Hospital in Göteborg, Sweden, and fulfilled the above given criteria.

RESULTS

In all, 1948 patients were included of whom 731 (38%) had a confirmed acute myocardial infarction (AMI). Independent risk indicators for death were: age (P=0.0001); male sex (P=0.005); a history of previous AMI (P=0.0001), diabetes mellitus (P=0.003) and smoking (P=0.0001); development of AMI during first 3 days in hospital (P=0.0001); in-hospital signs of congestive heart failure (P=0.0001); prescription of digitalis (P=0.001) and diuretics (P=0.02) at hospital discharge. A history of smoking interacted significantly (P=0.02) with the relationship between development of AMI and prognosis. Thus, the difference between patients who did and who did not develop an AMI was more pronounced among non-smokers than smokers. Other factors which interacted significantly with this relationship were a history of angina pectoris, and development of ventricular fibrillation and hypotension while in hospital.

CONCLUSION

Among hospital survivors of a confirmed or suspected acute coronary syndrome predictors of death during 5 years were: age, male sex, history of AMI, diabetes mellitus and smoking, development of AMI and congestive heart failure while in hospital and prescription of digitalis and diuretics at hospital discharge. A history of smoking and angina pectoris as well as development of hypotension and ventricular fibrillation while in hospital interacted significantly with the relationship between development of AMI and prognosis.

Improvement of ED prediction of cardiac mortality among patients with symptoms suggestive of acute myocardial infarction

A study was undertaken to evaluate the 1-year risk of cardiac death for patients with chest pain/suspected acute myocardial infarction in the emergency department (ED) and express the prognosis in a statistical model. Clinical variables and electrocardiogram were correlated to cardiac death during 1 year. Cox regression model was used to estimate the risk of death as a continuous function of a risk score and the time interval. From these, the prognosis for each patient can be calculated. There were 6,794 visits by 5,303 patients followed for 1 year, during which 604 patients died. The absolute risk of cardiac death can be calculated from the independent predictors for cardiac death: age; sex; histories of diabetes mellitus, hypertension, and congestive heart failure; and symptoms, electrocardiographic pattern, and degree of suspicion of acute myocardial infarction on admission. This model allows estimation of the prognosis for every patient with chest pain/suspected acute myocardial infarction from data easily available in the ED.

Risk indicators for death and prognosis among patients in whom acute myocardial infarction was not confirmed in relation to prescription of beta blockers at discharge

A large number of studies have shown the prognosis after acute myocardial infarction (AMI) to be favorably affected by treatment with beta blockers. Whether such treatment also will have a favorable effect on the prognosis in patients in whom AMI was not confirmed has not been shown. A study was undertaken at Sahlgren's Hospital, Göteborg, to determine risk indicators for death and prognosis among 1,443 patients in whom AMI was not confirmed and who survived hospitalization in relation to whether or not beta blockers were prescribed at discharge. One-year mortality was determined and p values were corrected for differences at baseline. Of the 1,443 patients who participated in the analyses, 44% were prescribed beta blockers. They differed from the remaining patients by younger age, predominance of men, a more frequent history of AMI, angina pectoris, and hypertension, and a less frequent history of congestive heart failure. Patients in whom beta blockers were prescribed had a 1-year mortality of 6% compared with 16% in those not on beta blockers (p < 0.001). The difference was similar in various subgroups according to clinical history.

Prognosis, severity of symptoms, and aspects of well-being among patients in whom myocardial infarction was ruled out

In a high proportion of patients hospitalized due to suspected acute myocardial infarction (AMI) the diagnosis cannot be confirmed. The majority of these patients have ischemic heart disease and are at risk for subsequent cardiac events. The aim of this study was to describe the severity of symptoms and various aspects of well-being 1 year after hospitalization due to suspected AMI in surviving patients in whom the diagnosis was not confirmed, and to relate the observations to those found among survivors of a confirmed AMI. All patients admitted to Sahlgrenska Hospital, Göteborg, due to suspected AMI and who were alive after 1 year were asked to answer a questionnaire including questions regarding cardiovascular, psychiatric, and psychological symptoms. Patients in whom AMI was not confirmed reported more cardiovascular symptoms, for example, chest pain (p < 0.001), dyspnea (p < 0.01), palpitations (p < 0.001), and fatigue (p < 0.01) when compared with patients who suffered confirmed AMI. The majority of psychosomatic and psychological parameters evaluated were also more frequently reported by these patients and their quality of life seems to be worse compared with survivors of AMI.

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.

Prognosis in diabetics in whom the initial suspicion of acute myocardial infarction was not confirmed

For 2,058 consecutive patients hospitalized for suspected acute myocardial infarction (AMI) but in whom AMI was later ruled out, we describe the prognosis with particular emphasis on diabetics. In all, a previous history of diabetes mellitus occurred in 290 (14%) of the patients. Compared with nondiabetics, they had a longer delay time between onset of symptoms and arrival in hospital. During 1 year of follow-up, their mortality rate was 28% compared with 14% for nondiabetics (p < 0.001), and their reinfarction rate was 20% compared with 10% for nondiabetics. More diabetics died in association with a fatal myocardial infarction and more frequently had ventricular fibrillation preceding death. With the exception of reinfarction, no clear difference in terms of morbidity was observed between the two groups. We conclude that the prognosis in diabetics in whom AMI is ruled out is poor, with between one-quarter and one-third not surviving 1 year.

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.

Three-year mortality in patients suspected of acute myocardial infarction with and without confirmed diagnosis. The Danish Study Group on Verapamil in Myocardial Infarction

The 3-year mortality from day 15 after admission was evaluated prospectively in 11,345 consecutive patients with chest pain suspected of myocardial infarction--4,265 patients with confirmed diagnosis (AMI) and 7,080 patients without confirmed diagnosis (non-AMI), respectively. The mortality rates per year in the first 3 years in the patients with AMI were 14.2%, 6.9%, and 7.6%, and in the non-AMI patients were 8.8%, 5.8%, and 5.5%. The standardized mortality ratio (SMR) correcting for age and sex differences was calculated. SMR is the ratio between the observed mortality in the study population and the expected mortality in an age- and sex-matched subgroup of the general background population. SMR in the first year was 6.7 (95% confidence limits: 6.2 to 7.2) in AMI and 4.7 (4.4 to 5.1) in non-AMI patients. In the second and third years of follow-up, SMR was 3.0 (2.6 to 3.4) and 2.9 (2.5 to 3.4) in AMI and 2.8 (2.5 to 3.1) and 2.4 (2.1 to 2.8) in the non-AMI patients. It is concluded that in the first 3 years the mortality of non-AMI patients is approximately three times higher than in the general population and very close to the late mortality of AMI patients, suggesting that the majority of non-AMI patients are suffering from ischemic heart disease also. Non-AMI patients should consequently be evaluated carefully prior to discharge.

One-year mortality rate after discharge from hospital in relation to whether or not a confirmed myocardial infarction was developed

Consecutive patients admitted to our hospital with suspected acute myocardial infarction during 21 months were prospectively evaluated. One-year mortality after discharge from hospital was related to whether or not an infarction developed (infarct versus non-infarct patients). Of patients discharged alive after developing an infarct, there was a mortality of 17% (n = 777) versus 12% (n = 1830) (P less than 0.001) for all patients not developing infarction. In a high risk group (any of the following: age greater than or equal to 75 years, previous history of myocardial infarction, diabetes mellitus or congestive heart failure) patients developing infarction had a mortality of 24% (n = 457) versus 17% (n = 1221) for those who did not (P less than 0.001). In a low risk group (none of the high risk criteria), the corresponding mortality was 8% (n = 316) for patients suffering infarction and 3% (n = 603) for those not having infarction (P less than 0.001). The difference in mortality between patients with and without infarction was most marked in women (21% vs 11%; P less than 0.01) and in hypertensives (25% vs 12%; P less than 0.001), but less marked in men (16% vs 13%; NS) and in patients without hypertension (13% vs 12%; NS). Among patients not suffering infarction, mortality was particularly high in those with previous congestive heart failure (23%) and diabetes mellitus (21%).

Mortality and morbidity during one year of follow-up in suspected acute myocardial infarction in relation to early diagnosis: experiences from the MIAMI trial

From a large randomized multicentre trial of metoprolol in suspected acute myocardial infarction (n = 5778) we report on the outcome during 1 year of follow-up, in relation to early diagnosis. Patients who developed a confirmed infarction had a 1-year mortality rate of 12.8%. This was significantly higher than the mortality rate of 6.3% (P less than 0.001) in patients with possible infarction and it was also higher than that in patients with no infarction, which was 5.0% (P less than 0.001). A multivariate analysis showed that independent risk predictors in the clinical history of patients without confirmed infarction were a history of angina pectoris, chronic use of digitalis and advanced age. After 1 year, angina pectoris was most common in patients with an initial possible infarction. These patients were also in most urgent need of bypass surgery. We thus conclude that the mortality during 1 year of follow-up among patients with an initially strongly suspected acute myocardial infarction was clearly related to whether or not the patient developed a myocardial infarction.

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

In a retrospective 6 year follow up data were obtained for 536 of 566 (95%) consecutive patients admitted to a coronary care unit with acute chest pain. Their diagnoses were acute myocardial infarction in 290 (54%), myocardial ischaemia in 164 (31%), pericarditis in 16 (3%), and non-cardiac in 66 (12%). Six year mortality was 36%, 24%, 0%, and 16% respectively. In patients with acute myocardial infarction a higher mortality rate during follow up was associated with a higher than average age, a higher than average creatine kinase, previous myocardial infarction, Q wave infarction, and the presence of reciprocal changes. The presence of reciprocal changes was associated with higher than average concentration of serum creatine kinase, indicating more extensive infarction. Infarction complicated by ventricular fibrillation or left bundle branch block was associated with a higher death rate. The electrocardiogram recorded at the time of acute myocardial infarction contains much useful prognostic information.

The prognosis of patients suspected of having acute myocardial infarction subsequent to its exclusion as the diagnosis

This review of the literature concerns the prognosis of patients suspected of having myocardial infarction subsequent to its exclusion as the diagnosis. Several investigations show a surprisingly bad prognosis for patients in this category, almost comparable to that of patients with a confirmed infarction. When the results of the different studies are pooled, however, there is a significant difference between those patients with true infarction, and those in whom infarction was excluded, in terms of overall mortality (12% and 7%; P less than 0.0001) and the development of subsequent non-fatal infarction (11% and 6%; P less than 0.05) when the results are analysed for a period of follow-up of one year. The difference was significant even when both fatal and non-fatal infarctions were taken into account over the one-year period of follow-up (13% and 8%; P less than 0.0001). The analysis shows that electrocardiographic ST-T changes are a risk factor for coronary events, but the results are conflicting for other possible risk factors. The selection of patients varies between the different studies, which probably contributes to the different results reported. Prospective studies with well defined groups of patients large enough to permit analysis of subgroupings will be needed to resolve the outstanding questions.

Long-term morbidity in patients where the initial suspicion of myocardial infarction was not confirmed

The morbidity and mortality during a 5-year follow-up in patients admitted to the coronary care unit with chest pain presenting an initial suspicion of acute infarction, but in whom the diagnosis could not be confirmed, is reported. They were divided into four groups: Possible myocardial infarction (29%), angina pectoris (24%), chest pain of uncertain origin (32%), and nonischemic cause of chest pain (15%). The overall 5-year mortality rate was 13.3% and did not differ substantially between the four groups. During the 5-year follow-up a confirmed myocardial infarction developed in 28% and 22% among patients with the diagnosis possible infarction and angina pectoris, respectively, and in about 10% of the remaining patients. Stroke developed in 4% of patients with possible infarction and in 2-3% in the remaining subgroups. In all, 59% of the patients were rehospitalized for a mean duration of 30 days in hospital. Among survivors at 5 years, 54% reported chest pain equivalent to angina pectoris and 25% had chest pain daily. A high prevalence of angina pectoris, a high frequency of rehospitalization due to chest pain, and a high consumption of cardiovascular drugs could be found in all four groups.

Risk factors and prognosis after discharge for patients admitted because of suspected acute myocardial infarction with and without confirmed diagnosis

The prognosis regarding cardiac events--acute myocardial infarction (AMI) or cardiac death after discharge--was evaluated in 257 patients admitted because of suspected AMI due to chest pain, but in whom AMI was not confirmed (non-AMI patients). The findings and patient prognoses were compared with those of 275 patients with confirmed AMI. All patients were younger than 76 years and free of severe chronic diseases, and no cause of chest pain other than possible ischemic heart disease was found. The patients were followed for cardiac events for 11 to 24 months (median 14). The prognoses for the non-AMI patients were significantly better than those for the AMI patients (p = 0.05). The proportion without a cardiac event after 1 year was estimated at 91% and 86%, respectively. In the non-AMI patients, angina pectoris, previous AMI and electrocardiographic changes on admission (intraventricular block and permanent or transient ST-T changes) were significant predictors of cardiac events by univariate and multivariate analysis. In the AMI patients, female gender, heart failure, previous AMI and angina pectoris were significant predictors of cardiac events by univariate analysis. With use of multivariate analysis, female gender, heart failure and angina pectoris were independent predictors of cardiac events. Thus, non-AMI patients admitted with chest pain have a high risk of cardiac events after discharge. The risk is highest when there is evidence of coronary artery disease (electrocardiographic changes on admission and angina pectoris or previous AMI.

Ventricular premature beats on Holter monitoring in patients admitted with chest pain, in whom acute myocardial infarction is not confirmed. The prognostic value and relationship to scars or ischemia on thallium-201 scintigraphy

Ambulatory 24-h Holter monitoring was carried out in 198 patients who had been admitted because of suspected acute myocardial infarction (AMI) due to chest pain, but in whom AMI was not confirmed. During a follow-up period of 12-24 months (median 14 months) 16 cardiac events (i.e., nonfatal AMI or cardiac death) occurred. Ventricular premature beats (VPBs) were found in 65.2% of the patients, complex VPBs in 28.8%. Pairs of VPBs which were seen in 10.0% of the patients were the only important type of VPBs significantly related to an impaired prognosis. Thallium-201 scintigraphy was performed in 144 of the patients. VPBs were significantly related to scar formation (i.e., to permanent defects, but not to ischemia, specifically, to transient defects). It is concluded that ventricular arrhythmias in this patient category indicate presence of chronic ischemic heart disease, and that pairs of VPBs seem to identify patients at risk for cardiac events.