Therapy for acute myocardial infarction in older persons

Care of the older patient with pain

The numbers of older people, particularly those older than 85 years of age, are increasing rapidly. Aging and chronic conditions contribute to the limitation in response to stress or insults in the elderly and impact assessment and management of pain. In older patients, careful evaluation of cognition is imperative to pain management, as is assessment of effectiveness and adverse reaction to treatments. Physiological alteration in body composition and renal and hepatic function alter distribution and elimination of medications and metabolites. Non-medical treatments also may be effective in managing pain and should be considered for older patients.

Efficacy of thrombolysis in younger and older adult patients suffering their first acute q-wave myocardial infarction

OBJECTIVES

Advancing age is an independent predictor of increased mortality after acute myocardial infarction (AMI). Several hypotheses have been developed to try to explain this phenomenon, but data available about the efficacy of thrombolytic therapy in older patients are still not conclusive. The goal of this study was to investigate the efficacy of thrombolysis in adult and older patients who suffered their first AMI.

DESIGN

Retrospective cohort study.

SETTING

A coronary care unit.

PARTICIPANTS

The sample included 244 younger (aged <65, n = 166) and older (age 65, n = 78) adult patients suffering their first Q-wave AMI, all receiving thrombolysis with human-recombinant tissue-type plasmin-ogen activator (100 mg total dose within 2.5 hours of the onset of AMI.

MEASUREMENTS

Infarct size was estimated by isoenzyme creatine kinase-myoglobin (CK-MB) release, measuring the area under the curve as a function of time. ST elevation, the sum of ST elevation above the baseline, and the sum of R wave height in precordial leads V1-V6 were evaluated using 12-lead electrocardiograms. Myocardial reperfusion was calculated when ST-segment elevation decreased more than 60 with respect to the most abnormal peak detected.

RESULTS

CK-MB peak level was significantly smaller in younger patients than in older ones (P< .01) and was significantly correlated with increasing age (P< .0001). Area under the 36-hour CK-MB curve was lower in younger patients than in older ones (P< .0001) and was well correlated with increasing age (P< .01). Reperfusion time was significantly shorter in younger patients (P< .05), and age was significantly correlated with reperfusion time (P< .001).

CONCLUSIONS

Infarct size was greater and reperfusion time was longer in older patients than in younger ones with first Q-wave AMI treated with thrombolysis. Infarct size and reperfusion time were linearly correlated with increasing age. These findings may help explain the increase in mortality due to AMI observed with advancing age.

Changes in mortality of acute myocardial infarction as a function of a changing treatment during the last two decades

Forty years ago, after the establishment of coronary care units, a significant decrease in mortality of acute myocardial infarction was noted. Twenty years ago, the break-through of thrombolysis realized once again a significant decrease in mortality. In this study we compare, in a rather small community hospital, the mortality and safety of thrombolytic therapy in acute myocardial infarction with a more conventional, conservative medical therapy. We examined all cases of acute myocardial infarction between 1978 up to 1998 inclusive, concerning treatment and mortality rate after a six month period. To be included in the study, acute myocardial infarction had to fulfill particular inclusion criteria. A total of 1863 cases of acute myocardial infarction were included. The mortality rate of patients with acute myocardial infarction treated with thrombolytic agents was strikingly lower and statistically very significantly different (p < 0.001) in comparison with the mortality rate of patients treated with heparin or coumarine derivatives. The mortality rate dropped from 10.57% in the coumarine group and from 14.95% in the heparin group to 5.41% in the alteplase group, to 4.95% in the anistreplase group and 4.00% in the streptokinase subgroup. The complications directly connected to the treatment did not seem to be different between the five groups, and they were also not more frequent by using thrombolytic agents. In the last 20 years, better preventive measures (life habits, diet, medication) and trials to better control the risk factors have not influenced greatly the average amount of cholesterol in patients with an acute myocardial infarction. Also the percentage of patients with high blood pressure has hardly decreased over the last 20 years. The mortality associated with acute myocardial infarction has decreased significantly with the use of thrombolytics. In most cases, thrombolytics are administered routinely and safely. In this way, they are the first choice therapy for myocardial infarction in smaller hospitals. To obtain excellent coronary patency, thrombolytic agents with a long half-life and with PAI-1 resistance are required in the future. The current measures and medical therapies seem to be insufficient to control the risk factors for coronary atherosclerosis.

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.

beta-blockers in heart failure: recently completed and ongoing clinical trials

beta-Blockers have emerged as an important therapy in patients with symptomatic left ventricular systolic dysfunction. Early studies demonstrated that beta-blocker therapy improved left ventricular function, reduced neurohumoral activity and reduced heart failure symptoms in these patients. While none of these small studies demonstrated a significant benefit in terms of overall survival, several meta-analyses suggested that beta-blocker therapy could, in fact, reduce mortality in patients with left ventricular systolic dysfunction and mild to moderate heart failure symptoms (New York Heart Association class II or III). Three large, recently completed, trials have confirmed the benefit of beta-blockade in these patients. This report reviews some of the initial clinical studies of beta-blockade in heart failure, examines the findings of the three large multicentre trials and other relevant research. Finally, ongoing trials designed to assess the relative efficacy of different beta-blockers and evaluate the utility of beta-blockade in specific subsets of patients with heart failure are discussed.

Modification of high blood pressure after myocardial infarction

The treatment of high blood pressure (BP) after myocardial infarction is extremely important to decrease reinfarction and mortality. BP should be controlled more strictly in this high-risk hypertensive population. Recently, many clinical trials have demonstrated the benefits of lifestyle modification and antihypertensive agents, particularly beta-blockers and angiotensin-converting-enzyme inhibitors for the treatment of acute myocardial infarction. Treatment with these agents that modify BP may benefit even normotensive patients after a myocardial infarction, although the benefit is greater in hypertensives.