[Early treatment of acute myocardial infarct: implementation of therapy guidelines in routine clinical practice, MITRA pilot phase]

Benefit of onsite reperfusion therapy or transfer to primary PCI in STEMI patients admitted to hospitals without catheterization laboratory. Results of the MITRA PLUS Registry

The optimal reperfusion strategy in elderly patients with ST-segment elevation myocardial infarction (STEMI) remains a topic of debate. Therefore, we investigated in the MITRA PLUS registry clinical outcome variables in 5455 patients aged>70 years and STEMI on admission at hospitals without the facilities of coronary catheterization and PCI. Outcome was compared after thrombolysis, transfer to PCI and after no reperfusion therapy. Data of this registry in STEMI patients older than 70 years, who were transferred to another hospital for PCI, showed a strong trend for lower in-hospital mortality rates compared with a strategy with sole fibrinolysis and significantly lower in hospital death rates compared with a conservative treatment without (medical or mechanical) reperfusion. Additionally, the PCI group also had a reduced incidence of the combined events: death, myocardial reinfarction, stroke in comparison with both other infarct groups. Data of the presented MITRA PLUS registry in STEMI patients older than 70 years support data of several other studies, that patients with STEMI benefit from a transfer to primary PCI even after a time delay of symptom onset to hospital admission of more than 2 h compared with a strategy using sole fibrinolytic therapy.

Incidence and clinical impact of right bundle branch block in patients with acute myocardial infarction: ST elevation myocardial infarction versus non-ST elevation myocardial infarction

BACKGROUND

Both left bundle branch block and right bundle branch block (RBBB) have been associated with increased inhospital and long-term mortality in patients with acute ST elevation myocardial infarction (STEMI). However, the prognostic role of RBBB in acute non-ST elevation myocardial infarction (NSTEMI) is not well known. Therefore, the aim of the study was to evaluate the incidence and clinical impact of RBBB in patients with NSTEMI compared to patients with STEMI.

METHODS

From the German prospective multicenter registry "Maximal Individual Therapy of Acute Myocardial Infarction" (MITRA PLUS), 6,403 consecutive patients with NSTEMI and 20,233 patients with STEMI were analyzed. Patients with left bundle branch block were excluded. The median follow-up time for NSTEMI was 378 days and for STEMI 479 days.

RESULTS

A total of 455 (7.1%) patients with NSTEMI and 894 (4.4%) patients with STEMI presented with RBBB on admission. In general, RBBB patients were older, more often had comorbidities, and less often received short-term inhospital treatment according to guidelines. In STEMI, RBBB patients had higher peak enzyme levels and lower left ventricular ejection fraction (LV-EF) than patients without BBB. Right bundle branch block in STEMI was associated with an increased inhospital and long-term mortality. In NSTEMI, however, peak enzyme levels and LV-EF were similar in both groups with and without RBBB. Right bundle branch block in NSTEMI was not independently associated with a worse outcome.

CONCLUSIONS

Unlike RBBB in STEMI, RBBB in NSTEMI is not an independent predictor of inhospital and long-term mortality.

Influence of presentation at the weekend on treatment and outcome in ST-elevation myocardial infarction in hospitals with catheterization laboratories

BACKGROUND

Studies about the influence of various factors on clinical therapy and course in acute coronary syndromes have shown that the outcome is related to admission time to the hospital, with an impaired prognosis in patients admitted out of regular working hours. However little is known about the impact of admission on weekend in hospitals with catheterisation laboratories.

METHODS

We analyzed data of the prospective MITRA-PLUS registry of 11,516 patients with ST-elevation myocardial infarction (STEMI) admitted to hospitals with catheterization facilities for differences of in-hospital mortality between patients admitted during regular working hours, at night and on weekends.

RESULTS

The prehospital delay and "door-to-balloon"-time were significantly longer on weekends and at nights than at regular working hours (median 196 Vs. 240 Vs. 155 min; P < 0.0001; 60 Vs. 84 min at weekends, resp. 75 min at nights; P < 0.0001). Reperfusion therapy was performed in 72.8% (8,248/11,332) patients, and there were less patients treated on weekend versus "on"-hours (69.7 Vs. 77 %, P < 0.0001). On weekends we found a significant higher in-hospital mortality (11.1 Vs. 9.4%, P = 0.01) and at night there was a trend to higher in-hospital mortality when compared with regular working hours (10.6 Vs. 9.4%, P = 0.07).

CONCLUSION

In patients with STEMI admitted to hospitals with catheterization facilities, admission during the "off"-hours is associated with higher in-hospital mortality. This may be due to lower rates of revascularization therapy and longer prehospital and in-hospital delays as compared to "on"-hours.

Impact of the body mass index on occurrence and outcome of acute ST-elevation myocardial infarction

Obesity is a traditional risk factor for the development of cardiovascular disease. However, recent studies have described a better outcome of obese patients in the clinical course of acute coronary syndromes.We investigated the impact of the body mass index (BMI) on occurrence and outcome of acute ST-elevation myocardial infarction (STEMI). Data of 10 534 consecutive patients with STEMI of the German MITRA PLUS registry were analyzed, comparing international classes of the BMI (obesity: BMI >or= 30 kg/m(2), overweight: 25-29.9 kg/m(2), normal weight: 18.5-24.9 kg/m(2)).STEMI occurred at a younger age in obese patients. The obese patients with first STEMI were 3 years younger than the normal weight patients with first STEMI (62.5 vs 65.7 years, p <0.0001).After STEMI has occurred, the obese patients had the lowest hospital (6.0%) and long-term mortality (4.8%) of all compared BMI-groups. In a multivariate analysis, obesity compared to normal weight was associated with a trend of a reduced mortality without significance during the hospital course (OR 0.81, 95% CI 0.60-1.08) and with significance during follow-up (OR 0.56, 95% CI 0.40-0.79).In conclusion, our data show that obesity is a risk factor of a manifestation of STEMI at a younger age compared to normal weight patients. After STEMI has occurred, obesity is associated with a trend of a lower mortality during the following clinical course. Therefore, the focus of prevention should be the reduction of obesity and metabolic syndrome in young people, to avoid the early occurrence of STEMI by primary prevention.

Prognostic impact of acute beta-blocker therapy on top of aspirin and angiotensin-converting enzyme inhibitor therapy in consecutive patients with ST-elevation acute myocardial infarction

The prognostic effect of beta-blocker treatment on ST-elevation acute myocardial infarction (STEMI) is controversially discussed in the era of reperfusion therapy. From the German multicenter registry Maximal Individual Therapy of Acute Myocardial Infarction PLUS (MITRA PLUS), 17,809 consecutive patients with STEMI treated with a guideline-recommended therapy with aspirin and an angiotensin-converting enzyme inhibitor were investigated; the prognostic effect of additional acute beta-blocker treatment was analyzed. Patients with cardiogenic shock were excluded. Of included patients, 77.6% received additional acute beta-blocker treatment and 22.4% did not. Patients with beta-blocker treatment were younger and more often received reperfusion therapy. Acute beta-blocker treatment was associated with a lower hospital mortality (univariate analysis 4.9% vs 10.8%, p <0.001; multivariate analysis odds ratio [OR] 0.70, 95% confidence interval [CI] 0.61 to 0.81). Acute beta blockade was significantly associated with a lower hospital mortality in patients without (OR 0.66, 95% CI 0.56 to 0.79) and with (OR 0.76, 95% CI 0.60 to 0.98) reperfusion therapy. The greatest benefit of acute beta-blocker treatment, measured by the number needed to treat to save 1 life, was found in patients with anterior MI, a heart rate > or =80 beats/min, no reperfusion therapy, female gender, and age > or =65 years. In conclusion, acute beta-blocker therapy in the clinical practice of treating patients with STEMI, in addition to aspirin and angiotensin-converting enzyme inhibitor therapy, was independently associated with a significant decrease in hospital mortality in patients with and without reperfusion therapy. High-risk patients with STEMI, such as elderly patients and patients without reperfusion therapy, showed a greater benefit of acute beta-blocker therapy than low-risk patients with STEMI.

Too little aspirin for secondary prevention after acute myocardial infarction in patients at high risk for cardiovascular events: Results from the MITRA study

BACKGROUND

A meta-analysis of randomized trials has shown a significant reduction of mortality rate in patients receiving aspirin for secondary prevention after acute myocardial infarction (AMI). However, a significant number of patients do not receive aspirin after AMI. Little is known about why aspirin is withheld or the long-term outcome of these patients today.

METHODS

The Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) registry is a multicenter registry of patients with AMI in Germany.

RESULTS

Of 4902 patients, 509 (10%) did not receive aspirin at the time of discharge from the hospital. The mean follow-up period for these patients was 17 months. Relative contraindications to aspirin were significantly associated with the withholding of aspirin (in-hospital bleeding: odds ratio [OR], 3.56; 95% CI, 1.86-6.80; history of peptic ulcer: OR, 2.49; 95% CI, 1.62-3.83). Absolute contraindications to aspirin were rare (2.2%). Other medications of proven benefit were also given less often in these patients (beta-blockers: 49.0% vs 61.9%, P <.001; angiotensin-converting enzyme inhibitors: 65.6% vs 70.2%, P =.06; statins: 12.2% vs 15.1%, P =.10). Patients who were not given aspirin were at high risk for vascular events. They were more likely to have a history of prior AMI (OR, 1.34; 95% CI, 1.02-1.79), were in critical clinical condition at admission more often (cardiogenic shock: OR, 1.98; 95% CI, 1.09-3.56; overt heart failure: OR, 1.6; 95% CI, 1.05-2.3), and received acute revascularization less often (OR, 1.32; 95% CI, 1.05-1.67). The 1-year mortality was 2-times higher in patients who did not receive aspirin than in patients who did receive aspirin (16.5% vs 8.3%, P <.001). A significant association of withheld aspirin at discharge with a higher long-term mortality rate was confirmed with multivariate analysis (OR, 1.62; 95% CI, 1.15-2.29).

CONCLUSIONS

Ten percent of patients who sustained an AMI did not receive aspirin at the time of hospital discharge. Most of these patients were at high risk for cardiovascular events. Withheld aspirin was significantly associated with higher mortality rate during follow up.

Comparison of clinical benefits of clopidogrel therapy in patients with acute coronary syndromes taking atorvastatin versus other statin therapies

In clinical practice, we found no significant difference between atorvastatin therapy or other statin therapies in the clinical outcomes of patients with acute coronary syndromes receiving clopidogrel therapy. In patients receiving atorvastatin therapy, clopidogrel therapy was associated with a significant decrease in mortality and stroke during univariate analysis and a moderate trend of reduced mortality and stroke without statistical significance in the multivariate analysis.

Antibiotic therapy after acute myocardial infarction: a prospective randomized study

BACKGROUND

Infection with Chlamydia pneumoniae is suspected to contribute to the pathogenesis of human atherosclerosis. We investigated whether treatment with the macrolide antibiotic roxithromycin would reduce mortality or morbidity in patients with an acute myocardial infarction.

METHODS AND RESULTS

Eight hundred seventy-two patients with an acute myocardial infarction (AMI) were randomly assigned to receive double-blind treatment with either 300 mg roxithromycin or placebo daily for 6 weeks. Primary end point was total mortality during 12-month follow-up. Four hundred thirty-three patients were treated with roxithromycin and 439 with placebo. With the exception of a higher proportion of patients suffering an anterior wall AMI (48.1% in the roxithromycin group versus 40.2% in the placebo group; P=0.027) and a lower prevalence of chronic obstructive pulmonary disease in the roxithromycin group (3.5% versus 6.9%, P=0.028), baseline characteristics, reperfusion therapy, and medical treatment were well balanced between the two groups. More patients in the roxithromycin group interrupted their study medication before completion of at least 4 weeks of treatment (78 of 433 [18%] versus 48 of 439 [11%]; P=0.003; odds ratio, 1.8; 95% CI, 1.2 to 2.6). Follow-up at 12 months was achieved in 868 of 872 (99.5%) patients. Total mortality at 12 months was 6.5% (28 of 431) in the roxithromycin group compared with 6.0% (26 of 437) in the placebo group (odds ratio, 1.1; 95% CI, 0.6 to 1.9; P=0.739). There were also no differences in the secondary combined end points at 12 months.

CONCLUSIONS

Treatment of AMI patients with roxithromycin did not reduce event rates during 12 months of follow-up. Therefore, our findings do not support the routine use of antibiotic treatment with a macrolide in patients with AMI.

Impact of ramipril versus other angiotensin-converting enzyme inhibitors on outcome of unselected patients with ST-elevation acute myocardial infarction

We examined the impact of treatment with ramipril versus other angiotensin-converting enzyme (ACE) inhibitors on clinical outcome in unselected patients of the prospective multicenter registry Maximal Individual Therapy of Acute Myocardial Infarction PLUS registry (MITRA PLUS). Of 14,608 consecutive patients with ST-elevation acute myocardial infarction, 4.7% received acute therapy with ramipril, 39.0% received other ACE inhibitor therapy, and 56.3% received no ACE inhibitor therapy. In a multivariate analysis, the treatment with ramipril compared with the treatment without ACE inhibitors was associated with a significantly lower hospital mortality and a lower rate of nonfatal major adverse coronary and cerebrovascular events. Compared with other generic ACE inhibitors, ramipril therapy was independently associated with a significantly lower hospital mortality (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.32 to 0.90) and a lower rate of nonfatal major adverse coronary and cerebrovascular events (OR 0.65, 95% CI 0.46 to 0.93), but not with a lower rate of heart failure at discharge (OR 0.79, 95% CI 0.50 to 1.27).

Gender differences in acute myocardial infarction in the era of reperfusion (the MITRA registry)

There is conflicting information about gender differences in presentation, treatment, and outcome after acute ST elevation myocardial infarction (STEMI) in the era of thrombolytic therapy and primary percutaneous coronary intervention. From June 1994 to January 1997, we enrolled 6,067 consecutive patients with STEMI admitted to 54 hospitals in southwest Germany in the Maximal Individual TheRapy of Acute myocardial infarction (MITRA), a community-based registry. Women were 9 years older than men, more often had hypertension, diabetes mellitus, and congestive heart failure, and had a history of previous myocardial infarction less often. Women had a longer prehospital delay (45 minutes), had anterior wall infarction more often (odds ratio [OR] 1.21; 95% confidence interval [CI] 1.08 to 1.36), and received reperfusion therapy less often (OR 0.83; 95% CI 0.74 to 0.94). The percentage of patients who were eligible for thrombolysis and received no reperfusion was higher in women (OR 1.7; 95% CI 1.56 to 1.89). Women had recurrent angina (OR 1.45; 95% CI 1.23 to 1.71) and congestive heart failure (OR 1.26; 95% CI 1.01 to 1.56) more often. There was a trend toward a higher hospital mortality in women (age-adjusted OR 1.16, 95% CI 0.99 to 1.35; multivariate OR 1.21, 95% CI 0.96 to 1.51), but there was no gender difference in long-term mortality after multivariate analysis (age-adjusted OR 0.95, 95% CI 0.78 to 1.15; multivariate OR 0.93, 95% CI 0.72 to 1.19). Thus, women with STEMI receive reperfusion therapy less often than men. They experience recurrent angina and congestive heart failure more often during their hospital stay. The age-adjusted long-term mortality is not different between men and women, but there is a trend for a higher short-term mortality in women.

Pre-hospital aspirin for suspected myocardial infarction and acute coronary syndromes: a headache for paramedics?

OBJECTIVE

To ascertain the frequency with which paramedics follow protocols for the administration of aspirin to patients to whom an ambulance is called for chest pain associated with suspected ischaemic heart disease.

METHODS

Ambulance services in England and Wales who had conducted a recent aspirin administration audit were identified through the National Clinical Effectiveness Programme for the Ambulance Service Association. Data were requested from each of these services with a 100% return rate.

RESULTS

Nine services out of a total of 35 had collected appropriate data. The proportion of patients who were given aspirin by a paramedic varied from 11% to 74%. The range of proportions of patients receiving pre-hospital aspirin increased after adding those patients who had already received aspirin from an alternative health provider, to 19% to 78%. It is estimated that at least 15% to 74% of patients who should have been given aspirin by the various ambulance services did not receive it. The proportion of patients for whom aspirin was judged to be inappropriate ranged from 4% to 35%. The reason for these widely varying and generally poor levels of compliance is not known. However, the range of indications and contraindications to the administration of aspirin varied considerably by ambulance service. This also made the comparison of data from different sources difficult.

CONCLUSIONS

Aspirin has been shown to be beneficial after a myocardial infarction and for other acute coronary syndromes. However, variances in the proportion of patients with suspected ischaemic heart disease given aspirin in different ambulance services indicates the need for a re-emphasis on the importance of this treatment. A standard protocol for all UK ambulance services should be devised that minimises the number of contraindications to aspirin and otherwise requires its administration to all patients with acute coronary syndromes or suspected myocardial infarction. Regular, standardised audits of compliance should also be conducted and their results widely disseminated.

Impact of prehospital delay on mortality in patients with acute myocardial infarction treated with primary angioplasty and intravenous thrombolysis

BACKGROUND

In patients with acute myocardial infarction treated with thrombolysis, longer times to treatment are associated with increasingly worse clinical outcome. This relation may be different for treatment with primary angioplasty.

METHODS

We analyzed the pooled data of the German acute myocardial infarction registries Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) and Myocardial Infarction Registry (MIR) to determine the influence of prehospital delays on hospital mortality rates. Primary angioplasty was performed in 1063 patients and thrombolysis in 7552 patients.

RESULTS

In patients treated with thrombolysis, in-hospital time to treatment was constantly 30 minutes median. In patients treated with primary angioplasty, in-hospital time to treatment increased from 60 minutes median up to 87 minutes median with increasing prehospital delay. Hospital mortality rates slightly decreased with increasing prehospital delays in patients treated with primary angioplasty (P for trend =.02). However, in patients treated with thrombolysis, mortality rate was nonsignificantly increased (P for trend =.11). Logistic regression analysis showed no significant difference in mortality rates between primary angioplasty and thrombolysis for prehospital delays of <3 hours. However, when prehospital delay was >3 hours, thrombolysis was independently associated with a higher mortality rate compared with primary angioplasty.

CONCLUSIONS

Compared with thrombolysis, primary angioplasty is independently associated with a lower mortality rate in prehospital delays of >3 hours. The reason for this may be a time-dependent loss of efficacy to achieve reperfusion for thrombolysis but not for primary angioplasty.

Primary angioplasty versus intravenous thrombolysis in acute myocardial infarction: can we define subgroups of patients benefiting most from primary angioplasty? Results from the pooled data of the Maximal Individual Therapy in Acute Myocardial Infarction Registry and the Myocardial Infarction Registry

OBJECTIVES

We sought to determine the effectiveness of primary angioplasty compared with thrombolysis in clinical practice.

BACKGROUND

In clinical practice, primary angioplasty for the treatment of acute myocardial infarction (AMI) has not yet been proven more effective than intravenous thrombolysis, nor have subgroups of patients been identified who would perhaps benefit from primary angioplasty.

METHODS

The pooled data of two AMI registries--the Maximal Individual TheRapy in Acute myocardial infarction (MITRA) study and the Myocardial Infarction Registry (MIR)--were analyzed. A total of 9,906 lytic-eligible patients with AMI, with a pre-hospital delay of < or =12 h, were treated with either primary angioplasty (n = 1,327) or thrombolysis (n = 8,579).

RESULTS

Despite differences in the patients' characteristics and concomitant diseases between the two groups, the prevalence of adverse risk factors was balanced. Univariate analysis of hospital mortality showed a more favorable course for patients treated with primary angioplasty: 6.4% versus 11.3% (odds ratio [OR] 0.54, 95% confidence interval [CI] 0.43 to 0.67). This was confirmed by logistic regression analysis (multivariate OR 0.58, 95% CI 0.44 to 0.77). Primary angioplasty was associated with a lower mortality in all subgroups analyzed. We observed a significant correlation between mortality and absolute risk reduction (r = 0.82, p < 0.0001) in the different subgroups: as mortality increased, there was an increase in absolute benefit of primary angioplasty compared with thrombolysis.

CONCLUSIONS

These large registry data showed the effect of primary angioplasty to be more favorable than thrombolysis for the treatment of patients with AMI in clinical practice. This effect was not restricted to special subgroups of patients. As mortality increased, the absolute benefit of primary angioplasty also increased.

Incidence, determinants, and clinical course of reinfarction in-hospital after index acute myocardial infarction (results from the pooled data of the maximal individual therapy in acute myocardial infarction [mitra], and the myocardial infarction registry [MIR])

There are few data about the incidence, determinants, and clinical course of in-hospital repeat acute myocardial infarction (RE-AMI) after an index AMI. From June 1994 to June 1998, 22,613 patients with AMI as an index event were registered by the Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) and Myocardial Infarction Registries (MIR). Of these, 1,071 (4.7%) had a RE-AMI. For the index event, 9,143 patients (40.5%) were treated with thrombolysis, 1,707 (7.5%) with primary angioplasty, and 443 (2.0%) with a combination of both. Multivariate analysis showed that previous AMI (odds ratio [OR] 1.59; 95% confidence intervals [CI] 1.35 to 1.86), age >70 years (OR 1.57; 95% CI 1.36 to 1.81), diagnostic first electrocardiogram (OR 1.37; 95% CI 1.19 to 1.59), and female gender (OR 1.14; 95% CI 1.05 to 1.32) were independently associated with a higher incidence of RE-AMI. The incidence of RE-AMI was higher when patients received thrombolysis (OR 1.36; 95% CI 1.15 to 1.61), and it was lower when they underwent primary angioplasty (OR 0.74; 95% CI 0.53 to 1.03) or received beta blockers (OR 0.84; 95% CI 0.72 to 0.97). Patients with RE-AMI had higher hospital mortality compared with those without RE-AMI (OR 4.35; 95% CI 3.83 to 4.95). Multivariate logistic regression analysis showed an independent association of RE-AMI with in-hospital death (OR 6.60; 95% CI 5.61 to 7.70), repeat revascularization (OR 2.91; 95% CI 2.42 to 3.50), low workload capacity on the bicycle ergometry test (OR 2.17; 95% CI 1.71 to 2.76), and ejection fraction <40% (OR 1.72; 95% CI 1.38 to 2.14) at discharge. Thus, RE-AMI occurs in 4.7% of patients after an AMI. Previous AMI, age >70 years, diagnostic first electrocardiogram, and female gender are independent determinants for RE-AMI. Thrombolysis is associated with a higher and beta blockers with a lower incidence of RE-AMI. Once a RE-AMI occurs, it is a strong predictor of in-hospital mortality and morbidity.

Characterization and clinical course of patients not receiving aspirin for acute myocardial infarction: results from the MITRA and MIR studies

BACKGROUND

Clinical trials have shown the efficacy of aspirin for acute myocardial infarction (AMI). However, not all patients receive aspirin for AMI. The aim of this study was to provide information on characteristics and clinical course of patients not treated with aspirin for AMI.

METHODS

We analyzed the data of the Myocardial Infarction Registry (MIR) and the Maximal Individual Therapy of Acute Myocardial Infarction (MITRA) registry. MITRA and MIR were prospective multicenter registries of patients with ST segment elevation myocardial infarction in Germany.

RESULTS

Of 22,572 patients registered from 1994 to 1998, 1767 (7.8%) did not receive aspirin within the first 48 hours after admission. Multivariate analysis revealed two main factors associated with withholding aspirin for AMI: relative contraindications to aspirin (gastric ulcer [odds ratio (OR) 4.9, 95% confidence interval (CI) 3.7-5.7], renal insufficiency [OR 1.4, 95% CI 1.1-1.8]), and critical clinical state at admission (cardiogenic shock [OR 1.5, 95% CI 1.2-2.1] and prehospital resuscitation [OR 1.8, 95% CI 1.4-2.2]). In addition, these patients were significantly less likely to receive reperfusion therapy and adjunctive medical therapy such as beta-blockers and angiotensin-converting enzyme inhibitors. In-hospital mortality after adjustment for baseline characteristics was 27.2% in patients without aspirin compared with 11.1% in patients treated with aspirin.

CONCLUSIONS

Only a minority of AMI patients (7.8%) did not receive aspirin. Relative contraindications to aspirin and a critical clinical state at admission were the main factors associated with withholding aspirin for AMI. Even after adjustment for patient characteristics, the mortality of patients without aspirin was almost three times higher.

Decreasing hospital mortality between 1994 and 1998 in patients with acute myocardial infarction treated with primary angioplasty but not in patients treated with intravenous thrombolysis. Results from the pooled data of the Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Registry and the Myocardial Infarction Registry (MIR)

OBJECTIVES

We investigated changes in the clinical outcome of primary angioplasty and thrombolysis for the treatment of acute myocardial infarction (AMI) from 1994 to 1998.

BACKGROUND

Primary angioplasty for the treatment of AMI is a sophisticated technical procedure that requires experienced personnel and optimized hospital logistics. Growing experience with primary angioplasty in clinical routine and new adjunctive therapies may have improved the outcome over the years.

METHODS

The pooled data of two German AMI registries: the Maximal Individual Therapy in AMI (MITRA) study and the Myocardial Infarction Registry (MIR) were analyzed.

RESULTS

Of 10,118 lytic eligible patients with AMI, 1,385 (13.7%) were treated with primary angioplasty, and 8,733 (86.3%) received intravenous thrombolysis. Patients characteristics were quite balanced between the two treatment groups, but there was a higher proportion of patients with a prehospital delay of >6 h in those treated with primary angioplasty. The proportion of an in-hospital delay of more than 90 min significantly decreased in patients treated with primary angioplasty over the years (p for trend = 0.015, multivariate odds ratio [OR] for each year of the observation period = 0.84, 95% confidence interval [CI]: 0.73-0.96) but did not change significantly in patients treated with thrombolysis. Hospital mortality decreased significantly in the primary angioplasty group (p = 0.003 for trend; multivariate OR for each year = 0.73, 95% CI: 0.58-0.93). However, for patients treated with thrombolysis, hospital mortality did not change significantly (p for trend 0.175, multivariate OR for each year: 1.02, 95% CI: 0.94- 1.11).

CONCLUSIONS

Compared with thrombolysis the clinical results of primary angioplasty for the treatment of AMI improved from 1994 to 1998. This indicates a beneficial effect of the growing experience and optimized hospital logistics of this technique over the years.

Acute myocardial infarction occurring in versus out of the hospital: patient characteristics and clinical outcome. Maximal Individual TheRapy in Acute Myocardial Infarction (MITRA) Study Group

OBJECTIVES

We describe the baseline characteristics and clinical course of patients who had an acute myocardial infarction (AMI) during their hospital stay.

BACKGROUND

In comparison with patients who had an AMI outside of the hospital (prehospital AMI), the data on patients who had an AMI in the hospital are poorly described.

METHODS

Patients with an in-hospital AMI were prospectively registered in the Southwest German Maximal Individual TheRapy in Acute myocardial infarction (MITRA) study and compared with patients with prehospital AMI.

RESULTS

Of 5,888 patients with AMI, 403 patients (6.8%) had an in-hospital AMI. These patients were older, more often male and sicker as compared with the patients with a prehospital AMI. They also showed a higher prevalence of concomitant diseases, such as arterial hypertension, diabetes mellitus, renal insufficiency and contraindications for thrombolysis. There was no significant difference regarding the use of reperfusion therapy, either thrombolysis (in-hospital AMI 44.2% vs. prehospital AMI 49.1%; odds ratio [OR] 0.86, 95% confidence interval [CI] 0.70 to 1.05) or primary angioplasty (9.9% vs. 8.2%; OR 1.23, 95% CI 0.88 to 1.73), or a combination of both, between the two groups. The interval from symptom onset to the start of treatment in patients receiving reperfusion therapy was 55 min for patients with an in-hospital AMI versus 180 min for patients with a prehospital AMI (p = 0.001). In-hospital death occurred in 110 (27.3%) of 403 patients with an in-hospital versus 762 (13.9%) of 5,485 patients with a prehospital AMI (OR 2.33, 95% CI 1.85 to 2.94). This was confirmed by logistic regression analysis after adjusting for other confounding variables (OR 1.67, 95% CI 1.23 to 2.24).

CONCLUSIONS

In-hospital AMI occurred in 6.8% of patients. Time to intervention was shorter; however, the use of reperfusion therapy for in-hospital AMI was not different from that for prehospital AMI. In particular, primary angioplasty seems to be underused in these patients. This, as well as the selection of patients, may result in the high hospital mortality rate of 27.3%.

Daytime and nighttime differences in patterns of performance of primary angioplasty in the treatment of patients with acute myocardial infarction. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

BACKGROUND

Concern exists regarding the results of primary angioplasty for acute myocardial infarction when the procedure is performed during night hours.

METHODS AND RESULTS

Between June 1994 and January 1997, 491 patients with acute myocardial infarction who underwent primary angioplasty procedures were consecutive registered in the Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) study. Three hundred seventy-eight patients (77%) were treated during the day and 113 (23%) at night. Baseline characteristics showed no major differences between the 2 groups. Prehospital delay time was 60 minutes shorter during the night (median value 180 minutes for day, 120 minutes for night, P =.005), and in-hospital time to treatment was 9 minutes longer (median value 85 minutes day, 94 minutes night, P =.037). Patients treated during the night more often received angiotensin-converting enzyme blockers (61.4% day, 76.1% night, P =.004) and the so-called optimal adjunctive therapy (54% day, 64.6% night, P =.045). There were no differences concerning clinical events between the 2 groups. Hospital mortality was 8.7% during the day and 5.3% during the night (univariate analysis P =.238; logistic regression P =.653).

CONCLUSIONS

In a clinical setting, primary angioplasty for acute myocardial infarction can be performed safely during the night with a clinically insignificant prolongation of in-hospital time to reperfusion compared with practice during the day.

After 4S, CARE and LIPID--is evidence-based medicine being practised?

Between 1994 and 1997, three major trials - 4S, CARE and LIPID - showed that simvastatin and pravastatin reduced the risk of a recurrent coronary event in patients with established coronary heart disease (CHD) [Scandinavian Simvastatin Survival Study (4S) Group. Lancet 1994;344:1383-89; Sacks FM et al. New Engl. J. Med. 1996;335: 1001-9; Long-term Intervention with Pravastatin in Ischaemic Disease (LIPID) Study Group. New Engl. J. Med. 1998;339:1349-57]. The results of CARE and LIPID, with pravastatin, also showed that the benefits of improved survival extended to the majority of patients with CHD whose cholesterol levels were in the 'normal' range. Despite this compelling evidence, recent CHD prevention surveys between 1994 and 1998 have unveiled a wide therapeutic gap between scientific evidence and practice in the secondary prevention of CHD. These recent surveys revealed a high prevalence of hypercholesterolaemia in patients discharged from hospital and after 6 months following a coronary event, but low levels of statin prescribing in these patients. Of the minority of patients prescribed a statin by a consultant on discharge from hospital, nearly all were still receiving this treatment in primary care 6 months later. These findings therefore clearly highlight the need for an integrated approach involving hospital specialists, primary-care physicians and the patient, to overcome the wide treatment gap in lowering even 'normal' cholesterol levels in high-risk patients in line with evidence-based medicine.

Primary percutaneous transluminal coronary angioplasty for acute myocardial infarction in patients not included in randomized studies. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

Patients with acute myocardial infarction included in randomized trials comparing primary percutaneous transluminal coronary angioplasty (pPTCA) with thrombolysis represent a special subgroup of patients with a low event rate. Patients excluded from these trials represent a variety of different subgroups, with different patient characteristics and possibly different clinical event rates. Primary PTCA was performed in 491 consecutive patients with acute myocardial infarction in the prospective multicenter observational Maximal Individual Therapy in Acute Myocardial Infarction trial. They were divided into the following groups: group I, patients fulfilling the inclusion criteria of the randomized trials (284 of 491, 58%); group II, patients not included in these trials (207 of 491, 42%). Of group II the following subgroups were defined: group IIa, patients in cardiogenic shock (20 of 491, 4.1%); group IIb, patients with a left bundle branch block (12 of 491, 2,4%); group IIc, patients with contraindications for thrombolysis (42 of 491, 8.6%); group IId, patients with a nondiagnostic first electrocardiogram (95 of 491, 19.3%); group IIe, patients with a prehospital delay of > 12 hours (72 of 491, 14.7%); group IIf, patients with an unknown prehospital delay (30 of 491, 6.1%). A comparison of groups I and II showed similar baseline characteristics but a higher clinical event rate during hospitalization was seen in group II: combined end point of death, reinfarction, heart failure equal to or greater than NYHA class III, any stroke or postinfarction angina, 26.6% versus 18%; p = 0.022. Hospital deaths were nearly twice as high in these patients, without reaching statistical significance (10.6% vs 6%; p = 0.06). The subgroups of group II showed quite different rates of clinical events. In-hospital death rates were: IIa, 40% (8 of 20); IIb, 8% (1 of 12); IIc, 12% (5 of 42); IId, 5% (5 of 95); IIe, 6% (4 of 72); and IIf, 13% (4 of 30). The incidence of the combined end point was 60% (12 of 20) in IIa, 33% (4 of 12) in IIb, 29% (12 of 42) in IIc, 16% (15 of 95) in IId, 26% (19 of 72) in IIe, and 33% (10 of 30) in IIf. Thus, in clinical practice, about half of the patients treated with pPTCA would not have been included in randomized trials comparing pPTCA with thrombolysis. These patients represent a population at higher risk for in hospital clinical events. However, they do represent very different nonhomogenous subgroups with different clinical event rates.

Differences in patients with acute myocardial infarction treated with primary angioplasty or thrombolytic therapy. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

BACKGROUND

Little is known about the differences in patients with acute myocardial infarction (AMI) treated with primary angioplasty or intravenous thrombolysis in clinical practice.

METHODS

In all, 5,906 patients with AMI were registered by the Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) study. Of these, 491 (8.3%) patients were treated with primary angioplasty and 2,817 (47.7%) with intravenous thrombolysis.

RESULTS

There were only minor differences in baseline characteristics between the two groups. Prehospital delay time (median) was longer in the angioplasty group than in the thrombolysis group (161 vs. 120, p = 0.001), as was door-to-treatment time (88 vs. 30 min; p = 0.001). Patients treated with primary angioplasty more often had contraindications for thrombolytic therapy (12.9 vs. 6%, p = 0.001) and received beta blockers (65 vs. 58.1%, p = 0.004), heparin (98.2 vs. 91.6%, p = 0.001), angiotensin-converting enzyme (ACE) inhibitors (64.8 vs. 50%, p = 0.001) and "optimal" concomitant medication (56.4 vs. 42.9%, p = 0.001) more often. Univariate analysis showed a significant lower incidence of heart failure (5.3 vs. 16.5%, p = 0.001), postinfarct angina (7.3 vs. 16.4%, p = 0.001), in-hospital death (7.9 vs. 11.7%, p = 0.015) and the combined end point (21.6 vs. 40.3%, p = 0.001) in these patients. Stepwise logistic regression analysis revealed optimal concomitant medication [odds ratio (OR) = 0.94, 95% confidence interval (CI): 0.89-0.98) and the type of revascularization (OR = 0.65, 95% CI: 0.58-0.73) to be associated with a significant reduction in the incidence of the combined end point. Similar results were obtained in all predefined subgroups.

CONCLUSIONS

In clinical practice, patients treated with primary angioplasty are more often treated with beta blockers and ACE inhibitors than patients treated with intravenous thrombolysis. Thus, the selection of patients and the type of revascularization contributes to the reduction in mortality, overt heart failure, and postinfarct angina in these patients.

Comparison of primary angioplasty with conservative therapy in patients with acute myocardial infarction and contraindications for thrombolytic therapy. Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) Study Group

The benefit of primary angioplasty in patients with acute myocardial infarction (AMI) and contraindications for thrombolysis compared to a conservative regimen is still unclear. Out of 5,869 patients with AMI registered by the MITRA trial, 337 (5.7%) patients had at least one strong contraindication for thrombolytic therapy. Out of these 337 patients 46 (13.6%) were treated with primary angioplasty and 276 (86.4%) were treated conservatively. Patients treated conservatively were older (70 years vs. 60 years; P=0.001), had a higher rate of a history with chronic heart failure (14.8% vs. 4.4%; P=0.053), a higher heart rate at admission (86 beats/min vs. 74 beats/min; P=0.001), and a higher prevalence of diabetes mellitus (27.1% vs. 12.8%; P=0.056). Patients treated with primary angioplasty received more often aspirin (91.3% vs. 74.6%; P=0.012), beta-blockers (60.9% vs. 46.1%; P = 0.062), angiotensin converting enzyme (ACE) inhibitors (71.7% vs. 44%; P=0.001), and the so-called optimal adjunctive medication (54.4% vs. 32.3%; P=0.004). Hospital mortality was significantly lower in patients who received primary angioplasty (univariate: 2.2% vs. 24.7%; P=0.001; multivariate: OR=0.46; P=0.0230). In patients with AMI and contraindications for thrombolytic therapy, primary angioplasty was associated with a significantly lower mortality compared to conservative treatment. Therefore, hospitals without the facilities to perform primary angioplasty should try to refer such patients to centers with the facilities for such a service, if this is possible in an acceptable time.

Impact of early risk stratification on the length of hospitalization in patients with acute Q-wave myocardial infarction. 'The 60-minutes myocardial infarction project'

An assessment of individual risk factors may identify a subgroup of postinfarction patients at low risk, i.e. patients appropriate for early discharge. Using a large unselected population of the national registry, 'The 60-Minutes Myocardial Infarction Project', we (1) attempted to provide a retrospective analysis of clinical factors and in-hospital mortality in a population living on the 6th hospital day following admission to define a low-risk patient group with a residual in-hospital mortality of less than 1% eligible for early discharge, and (2) to analyze the current impact of risk stratification based on these clinical factors on the length of hospitalization. The study group consisted of 12,045 survivors on the 6th day after admission out of 14,980 patients of the registry with proven Q-wave myocardial infarction. Risk modeling was performed with multiple logistic regression.

RESULTS

A total of 873 patients (7.3%) died after day 6 in hospital. The most important prognostic factors were cardiopulmonary resuscitation prior to admission (odds ratio, OR: 7.2, confidence interval, CI: 5.11-10.22), thrombolysis complicated by severe bleedings (OR: 6.2, CI: 1.2-31. 2) and age >70 years (OR 4.7, CI 3.51-6.39). The other more significant independent predictors of increased mortality were end-stage renal disease, age between 56 and 70 years, systolic blood pressure <95 mm Hg on admission, history of trauma </=2 months, cancer and left-bundle-branch block. Summarizing these nine groups of patients with the strongest association to in-hospital mortality, we defined a high-risk group comprising 79% of the AMI patients with a residual in-hospital mortality of 8.8%. On the other hand, by excluding these nine high-risk patient groups, a low-risk group of 21% of all AMI patients seems to be appropriate for early discharge (residual in-hospital mortality = 1.07%). However, in the current practice, there was no difference regarding the median length of hospital stay between the two risk groups. The low-risk patients were hospitalized 20 days compared to 22 days in the high-risk patients.

CONCLUSION

Using a simple logistic regression model, which considers clinical factors of the early hospital phase, one fifth of the infarction patients can be stratified to be at low risk, and might be eligible for early hospital discharge. Currently, an individual risk stratification has no impact on the length of hospital stay in Germany.