Management and outcome of acute myocardial infarction in older patients in the thrombolytic era

Post-myocardial infarction beta-blocker therapy: the bradycardia conundrum. Rationale and design for the Pacemaker & beta-blocker therapy post-MI (PACE-MI) trial

Multiple clinical trials have demonstrated beta-blockers improving survival after myocardial infarction (MI). Patients with "bradycardia-related" contraindications to beta-blockers, such as those with asymptomatic bradycardia or AV conduction abnormalities, have been excluded from clinical trials of beta-blockers and continue to be excluded from post-MI beta-blocker therapy in routine clinical practice. These patients tend to be elderly and have a high 1-year mortality. If beta-blockers provide benefit to the post-MI patient independent of their heart rate-lowering effect, then these patients could benefit substantially from initiation of beta-blocker therapy. However, in this particular group of patients, beta-blockers can be safely initiated only if more severe or significant bradycardia can be prevented by pacemaker implantation. It is unclear whether adverse effects related to pacemaker implantation could also negate some or all of the hypothesized benefit of beta-blocker therapy. Although beta-blockers are particularly effective in the elderly, the benefit of beta-blocker therapy in patients with bradycardia-related contraindications to beta-blockers has not been established. The PACE-MI trial is a randomized controlled trial that will address whether beta-blocker therapy enabled by pacemaker implantation is superior to no beta-blocker and no pacemaker therapy after MI in patients with rhythm contraindications to beta-blockers or in those who have developed symptomatic bradycardia due to beta-blockers. The trial will randomize 1124 patients to standard therapy (not to include beta-blockers as patients must have a contraindication to be enrolled) or standard therapy plus pacemaker implantation and beta-blocker. The primary end point is the composite end point of total mortality plus nonfatal reinfarction.

Treatment and short-term outcome in women and men with acute coronary syndromes

OBJECTIVE

To study differences in treatment and early morbidity and mortality in relation to gender, type of acute coronary syndrome (ACS) and age in patients under 80 years of age.

METHODS

We studied 1744 consecutive patients with ACS with assumed decreasing order of severity [ST-elevation myocardial infarction (MI), non-ST-elevation MI and unstable angina of high- and low-risk types] admitted to the coronary care unit at Sahlgrenska University Hospital.

RESULTS

The use of thrombolysis and percutaneous coronary interventions (PCI) did not differ significantly between gender groups and women did not suffer from more severe complications than men. Treatment with beta-blockers, ACE inhibitors and aspirin was used on a similar scale among women and men. In-hospital complications and use of intravenous drugs were strongly associated with severity of disease in a similar way among women and men. The mortality rates at 30 days were 12.4% and 7.4% in MI with and without ST-segment elevation, but only 1.3% and 1.0% in unstable angina of high- and low-risk types. The use of primary PCI decreased with age, as did coronary angiography and PCI in the subacute phase, irrespective of gender.

CONCLUSION

Among patients <80 years with ACS admitted to a coronary care unit, the suspicion that women are treated less aggressively than men could not be verified. Nor did women suffer from more complications or have a significantly higher 30-day mortality than men. Elderly patients were significantly less likely to undergo invasive procedures than those of a younger age, irrespective of gender.

State of the science for care of older adults with heart disease

This article provided an overview of the current state of knowledge related to cardiovascular disease in elders. Some depth has been provided related to CHD and HF, two common diagnoses in older persons. The most striking finding is that although trials are increasingly including older cohorts of patients, research specifically testing known therapies in older patients is essential. In particular, research testing the safety, efficacy, and acceptability of therapies in the oldest old is greatly needed.

Influence of age on clinical course, management and mortality of acute myocardial infarction in the Spanish population

BACKGROUND

To assess age-related differences in cardiovascular risk factors, clinical course and management of patients with acute myocardial infarction (AMI) in intensive care (ICU) or coronary care units (CCU).

METHODS

A retrospective cohort study was conducted of all AMI patients listed in the ARIAM register (Analysis of Delay in AMI), a multi-centre register in which 119 Spanish hospitals participated. The study period was from January 1995 to January 2001. A univariate analysis was carried out to evaluate differences between different age groups. Multivariate analysis was used to assess whether age difference was an independent predisposing factor for mortality and for differences in patient management.

RESULTS

17,761 patients were admitted to the ICUs/CCUs with a diagnosis of AMI. The distribution by ages was: <55 years, 3,954 patients (22.3%); 55-64 years, 3,593 (22.2%); 65-74 years, 5,924 (33.4%); 75-84 years, 3,686 (20.8%); and >84 years, 604 (3.4%) (P<0.0001); 24.6% of the patients were female, and the relative proportion of females increased with age. There were clear differences in risk factors between the different age groups, with a predominance of tobacco, cholesterol and family history of heart disease in the younger patients. The incidence of complications, including haemorrhagic complications, increased significantly with age. The older age groups had a lower rate of thrombolysis and less use of revascularisation techniques. The mortality of the above groups was 2.6, 5.4, 10.7, 17.7 and 25.8%, respectively. Age difference was an independent predictive variable for mortality and the administration of thrombolysis.

CONCLUSIONS

The distinct age groups differed in cardiovascular risk factors, management and mortality. Age is a significant independent predictive variable for mortality and for the administration of thrombolysis.

Use of reperfusion therapies in elderly patients with acute myocardial infarction

Almost one-third of patients with acute myocardial infarction (AMI) are aged >75 years, and this proportion is expected to increase as the population ages. Mortality and complication rates are particularly high in the elderly, yet reperfusion therapies, including thrombolysis and primary percutaneous transluminal coronary angioplasty (PTCA), are under-utilised among eligible patients. There is a concern, whether real or perceived, that the risks of such therapies may outweigh the potential benefits. Presently, there are no randomised clinical trials of thrombolytic therapy in the elderly that definitively assess its efficacy in patients aged >75 years. In the meta-analysis of randomised trials by the Fibrinolytic Therapy Trialists, thrombolysis was associated with a mortality reduction among patients aged >75 years, though this reduction did not meet formal statistical significance. Because the point estimates for mortality reduction were in the direction that favoured use of thrombolytic therapy, the American Heart Association/American College of Cardiology AMI guidelines recommend thrombolysis as a Class 2a therapy in this age group. Observational studies using data from the Cooperative Cardiovascular Project database and the National Registry of Myocardial Infarction have recently cast some doubt on the benefit of thrombolysis among the elderly, but definitive answers from a randomised trial are still lacking. Meanwhile, primary PTCA, which has been compared to thrombolysis in both trial and observational settings, appears to offer the mortality benefit of reperfusion with lower stroke rates. Since primary PTCA is not widely available, efforts must be made to maximise available therapies in the elderly. Early diagnosis is essential, as is prompt reperfusion among eligible patients, since delay is so strongly associated with mortality with both thrombolysis and PTCA. Finally, newer, more fibrin-specific thrombolytics may decrease the bleeding risk associated with thrombolytic therapy.

Changes in the management of acute myocardial infarction in Southern Tasmania

BACKGROUND

In recent years, the management of acute myocardial infarction (AMI) has been the subject of many clinical trials. These studies have clearly established the value of using pharmacological agents, including aspirin, beta-blockers, thrombolytics and angiotensin converting enzyme (ACE) inhibitors. There have been suggestions, however, that practice has been slow to change in light of the findings of these trials.

AIM

To review cases of AMI at the major teaching hospital in Tasmania, Australia, to determine whether the recommendations from the results of the trials had been translated into local clinical practice, and to examine temporal changes in drug usage and clinical outcomes.

METHODS

A retrospective review of the medical records of patients admitted to the hospital with an AMI during 1996 and for the first four months of 1998 was performed. An extensive range of demographic and clinical variables was recorded, and differences between the 1996 and 1998 patients and between recipients and non-recipients of the different pharmacological agents were statistically evaluated.

RESULTS

The patients had a mean age of 65.9 +/- 12.3 years in 1996 (n = 205) and 66.8 +/- 12.3 years in 1998 (n = 71), with males accounting for 64.4% of cases in 1996 and 64.8% of cases in 1998. There were no significant demographic or medical history differences between the two groups. The median time of presentation after the onset of chest pain was 3.5 h in 1996 and 4 h in 1998. The rates of use of major therapeutic interventions post-AMI for 1996 and 1998, respectively, were: aspirin (89.1%, 90.3%), streptokinase (18.5%, 9. 9%), r-tPA (14.1%, 21.1%), intravenous beta-blockers (11.2%, 7.0%), oral beta-blockers (67.2%, 49.3%; P < 0.01), ACE inhibitors (44.4%, 59.2%; P < 0.05), intravenous nitrate (94.1%, 91.6%), oral nitrate (22.9%, 26.8%), calcium channel antagonists (19.5%, 35.2%; P < 0.05), cholesterol lowering agents (26.3%, 40.9%; P < 0.05), antiarrhythmics (21.5%, 25.4%) and warfarin (8.3%, 9.9%). Patients who received therapy with each of aspirin, r-tPA, intravenous beta-blockers, oral beta-blockers, intravenous nitrate and cholesterol lowering agents were significantly younger than the non-recipients (all P < 0.01), while patients treated with ACE inhibitors and antiarrhythmics were significantly older than the non-recipients (both P < 0.001). Non-recipients of thrombolytics presented to hospital significantly later, on average, than recipients. The hospital mortality rate was 15.1% in 1996 and 12.7% in 1998, and adverse drug reactions occurred in 21.5% of patients in 1996 and 15.5% in 1998.

CONCLUSION

Although there have been substantial increases in the use of ACE inhibitors and cholesterol lowering agents post-AMI in recent years, reductions in the use of thrombolytics and beta-blockers and their possible underuse in the elderly are of concern and warrant intervention.