NEWS BRIEFS
NEWS BRIEFS
Blood vessel inflammation slows thrombolysis
Recent research shows that inflammation not only precedes and helps trigger a heart attack, but may also limit the effectiveness of thrombolytic treatment, according to a study presented last fall at the American Heart Association’s 71st scientific sessions in Dallas.
It is known that patients with high blood levels of C-reactive protein, a marker of inflammation, have slow responses to thrombolytic treatment. Recent studies suggests that infections, such as chronic bronchitis, pneumonia, or dental infection may increase the risk of heart attack. Such infections may trigger a protective immune response that may cause blood vessels to become inflamed and resistant to thrombolytic treatment.
Researchers who presented at the conference studied 24 patients who received thrombolytic therapy after a heart attack.
Angiography revealed that arteries were still blocked in eight individuals and reopened in 14. Higher C-reactive protein levels indicated a higher level of inflammation, and, said researchers, "we found that inflammation impeded response time to clot-dissolving drugs. The higher the degree of inflammation, the longer it took for these patients’ arteries to open."
Anti-inflammatory drugs such as aspirin could be helpful in speeding the effects of the thrombolytics and reducing the amount of damage to the heart. "Most patients already receive aspirin after thrombolytic therapy. Maybe it would be a good idea to use the aspirin earlier during treatment," researchers said.
Pre-op nitrates therapy may affect in-hospital mortality
A recent study found that preoperative therapy with nitrates may increase the risk of in- hospital mortality following surgery for coronary artery disease (CAD).1
But use of beta-blockers may confer protective benefits, wrote the investigators who examined the results of various drug therapies before surgery in 1,600 patients. The drugs they studied for possible benefits were beta-blockers, aspirin, calcium antagonists, angiotensin converting enzyme (ACE) inhibitors, digoxin, and warfarin. The only ones to affect the risk of inhospital mortality after nitrate therapy were beta-blockers. Nitrate therapy was associated with a "statistically and clinically significant" fourfold increased risk of mortality, while that risk was .4 for patients on beta-blockers.
The authors speculated that the increased mortality rate linked to preoperative nitrate use could be due to the development of tolerance to nitrates. Alternatively, the cessation of nitrate therapy may cause rebound coronary vaso-constriction and worsening of myocardial ischemia. They wrote that the association could also be the result of a more severe underlying pathology in patients prescribed nitrates compared with those using other drugs for the management of CAD. The relevance of the protective effect of beta-blockers observed in the study is unclear, state the investigators, but it "supports the generally accepted practice of continuing treatment with beta-blockade until the morning of surgery in cardiac surgical patients."
Reference
1. Anesth Analg 1999; 88:286-291.
Quinapril reduces ischemic events after CABG
Long-term treatment with the ACE (angiotensin converting enzyme) inhibitor quinapril (Dallas-based Parke-Davis’s Accupril) can achieve an 80% reduction in ischemic events in patients who underwent a bypass, according to research presented at the American Heart Association’s 71st scientific sessions in Dallas last fall.
The results of the QUO VADIS study (effects of Quinapril On Vascular ACE and Determinants of Ischemia) shows that the use of the drug resulted in a clinically significant reduction in ischemic events — only 4% in the quinapril group vs. 18% in the placebo group one-year post-bypass. The study compared the efficacy of quinapril 40 mg/day vs. placebo on ischemia in 149 patients who underwent bypass. Clinical ischemic events were defined as re-onset of angina pectoris needing medical treatment, myocardial infarction, ischemic stroke, or transient ischemic attack.
Warning: Pacemaker batteries may fail
Guidant Corp. in Indianapolis has issued a warning to closely monitor patients who wear certain brands of the company’s pacemakers, because the batteries that power the devices can wear out sooner than expected.
Batteries in pacemakers typically last seven years, but those in affected devices could drain in six months. Examine patients with the affected devices on a monthly basis for up to six months for signs of premature battery failure. Patients with the faulty devices who require a new unit can get one from the company for free. Call (800) CARDIAC (227-3422), or go to www.guidant.com for more information.
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