Primary angioplasty for acute myocardial infarction in the elderly

[Therapy of cardiogenic shock after myocardial infarction]

The therapy of infarct related cardiogenic shock should primarily focus on fastest possible revascularization. In addition, rapid restoration of sufficient organ perfusion pressure is recommended for the prevention of a multi-organ dysfunction syndrome (MODS). This can be achieved by mechanical circulatory assist devices as well as individual catecholamine therapy. Since assist devices require specially trained physicians, their use is limited to specialized cardiac care centers. However, future technologies such as portable heart-lung-machines may help to further improve transfer to specialized centers and therapy of shock patients.

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.

Outcomes of elderly patients with cardiogenic shock treated with early percutaneous revascularization

BACKGROUND

Subgroup analysis from the Should We Emergently Revascularize Occluded Coronaries for Cardiogenic Shock (SHOCK) trial indicated that patients with acute myocardial infarction (MI) complicated by cardiogenic shock (CS) who were > or =75 years old did not benefit from early revascularization and may have been harmed; their mortality rate at 30 days was 75%. The applicability of this subset analysis from a select patient population enrolled in a randomized trial to the general population is unclear.

METHODS

At the Mayo Clinic between 1991 and 2000, we evaluated the outcome of all patients > or =75 years old with CS caused by MI who underwent urgent percutaneous coronary intervention (PCI).

RESULTS

The study included 61 patients with a mean age of 79.5 +/- 3 years; 21% of these patients had a history of prior coronary artery bypass grafting (CABG), 41% had had a prior MI, 28% had diabetes mellitus, and 18% had a history of a cerebrovascular accident (CVA). PCI was performed 8.0 +/- 7.2 hours after onset of MI. Angiographic success (<50% residual stenosis) was achieved in 91% of the lesions that were dilated. In hospital outcomes included death (44%), CABG (1.6%), and CVA (4.9%). The 30-day mortality rate was 47%. The estimated survival rate 1 year after discharge (Kaplan Meier method) was 75%.

CONCLUSIONS

These data confirm a high early mortality rate among patients > or =75 years old with MI complicated by CS, but suggest that among patients referred for angiography, outcomes may be better than previously believed when early revascularization is performed. In this population, 56% of patients survived to be discharged from the hospital, and of the hospital survivors, 75% were alive at 1 year.

Thrombolysis in elderly patients with acute myocardial infarction

The efficacy of thrombolytic therapy in the elderly remains a topic of ongoing debate. Although elderly patients account for a disproportionate amount of cardiovascular mortality, they have typically been underrepresented in randomized clinical trials. A meta-analysis of these trials suggests a survival benefit, albeit small, of thrombolytic therapy in the elderly. Thrombolytic therapy, in combination with either glycoprotein IIb/IIIa inhibitors or low-molecular weight heparin, poses an increased hazard in the elderly. Observational studies of thrombolytic therapy in the elderly portray a far worse outcome than the randomized clinical trials and raise the possibility of increased mortality. To date, no randomized trial has compared thrombolytic and primary coronary intervention in the elderly. However, multiple observational studies indicate a low risk of intracerebral hemorrhage and improved survival when a strategy of primary coronary intervention is employed. Future trials and observational studies should elucidate the ideal reperfusion strategy in the elderly.

Myocardial infarction in the elderly: benefits and risks of thrombolytics

Patients aged 75 years and older comprise 36% of all patients with myocardial infarction and 60% of all deaths from myocardial infarction in the US. Data from randomised, placebo-controlled clinical trials and observational data demonstrated a beneficial effect of thrombolytic therapy in eligible patients with acute myocardial infarction younger than 75 years of age. The overall data support the use of thrombolytic therapy in eligible patients with acute myocardial infarction aged 75 years and older. There is an urgent need to conduct a large-scale, prospective, double-blind, randomised, placebo-controlled trial investigating the effect of thrombolytic therapy on the combined endpoint of all-cause mortality plus cerebral bleeding at hospital discharge and at long-term follow-up in eligible patients aged 75 years and older with acute myocardial infarction. Current guidelines for the care of patients with acute myocardial infarction from the American College of Cardiology/American Heart Association support the use of thrombolytic therapy in eligible patients aged 75 years and older who present within 12 hours of symptom onset of acute myocardial infarction as a Class IIa indication, that is, one for which the weight of evidence/opinion is in favour of usefulness/ efficacy. Absolute contraindications to thrombolytic therapy include prior haemorrhagic stroke, other cerebrovascular events within 1 year, active internal bleeding, known intracranial neoplasm, suspected aortic dissection, and acute pericarditis. Stroke is a potential risk of the use of thrombolytics.

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.

Efficacy and age-related effects of nitric oxide-releasing aspirin on experimental restenosis

Restenosis after percutaneous transluminal coronary angioplasty is caused by neointimal hyperplasia, which involves impairment of nitric oxide (NO)-dependent pathways, and may be further exacerbated by a concomitant aging process. We compared the effects of NO-releasing-aspirin (NCX-4016) and aspirin (ASA) on experimental restenosis in both adult and elderly rats. Moreover, to ascertain the efficacy of NCX-4016 during vascular aging, we fully characterized the release of bioactive NO by the drug. Sprague-Dawley rats aged 6 and 24 months were treated with NO releasing-aspirin (55 mg/kg) or ASA (30 mg/kg) for 7 days before and 21 days after standard carotid balloon injury. Histological examination and immunohistochemical double-staining were used to evaluate restenosis. Plasma nitrite and nitrate and S-nitrosothiols were determined by a chemiluminescence-based assay. Electron spin resonance was used for determining nitrosylhemoglobin. Treatment of aged rats with NCX-4016 was associated with increased bioactive NO, compared with ASA. NO aspirin, but not ASA, reduced experimental restenosis in old rats, an effect associated with reduced vascular smooth muscle cell proliferation. NCX-4016, but not ASA, was well tolerated and virtually devoid of gastric damage in either adult or old rats. Thus, impairment of NO-dependent mechanisms may be involved in the development of restenosis in old rats. We suggest that an NCX-4016 derivative could be an effective drug in reducing restenosis, especially in the presence of aging and/or gastrointestinal damage.

Treatment of acute myocardial infarction

Persons 75 years of age or older constitute 6.1% of the US population but account for 36% of acute myocardial infarctions (MI) and 60% of deaths. Unfortunately, despite the fact that patients over age 75 represent a large subgroup with an exceptionally high case-fatality rate, most randomized clinical trials have enrolled few patients in this group. As a result, therapeutic recommendations for managing acute MI in the very elderly are often extrapolated from studies conducted in younger patients. This article reviews current evidence-based guidelines for early treatment of acute MI in the elderly. As in younger patients, aspirin, beta blockers, and angiotensin-converting enzyme inhibitors should be considered standard therapy in appropriately selected elderly patients. Although the benefits of reperfusion therapy (i.e., thrombolysis and primary angioplasty) are less well established, advanced age per se should not be considered a contraindication to the use of these interventions. Given the relative paucity of data in the very elderly, additional studies are needed to define optimal pharmacologic and nonpharmacologic treatment of acute MI in this rapidly growing, high-risk population.