NEWS BRIEFS
June 1, 1999 7 minutes read
NEWS BRIEFS
Computers beat out staff
Is drug dosing best left to computers? Maybe, according to British investigators who recently reported that computerized anticoagulant dosing may be more effective than traditional methods, where the medical staff decide whether or not doses should be increased, decreased, or remain unchanged, and the length of time that should elapse before the patient’s next visit.1
The researchers used a computer program that generates dosing schedules and conducted a prospective, multicenter trial involving 285 patients who were all on anticoagulant therapy, either in the first stages of therapy when a maintenance dose is established, or in a stable routine of anticoagulation. Participants were randomized to either computerized or traditional anticoagulant dosing for periods of at least three months.
Program has better-maintained INR control
During the first few weeks of the trial, staffers made many of the decisions themselves, owing to mistrust of the computer program. But after a few weeks, they stopped intervening and used only computerized doses to monitor patients. The authors wrote that the program maintained international normalized ratio (INR) control better than the experienced medical staff. Patients randomized to computer dosing spent an average of 63% of treatment days within target INR range, compared with 53% of days among subjects in the traditional-dosing group. The authors speculate that a wider use of computerized dosing could substantially save medical, nursing, and administrative time; and human attention could be concentrated on the few patients who present unusual difficulties for anticoagulant control.
Reference
1. Poller L, et al. Multicentre randomised study of computerised anticoagulant dosage. Lancet 1998; 352:1,505-1,509.
Spinal cord stimulation promising angina treatment
Electro-stimulation of the spinal cord may have anti-ischemic effects in patients with intractable angina, according to data published by a group of researchers from the Netherlands.1
The researchers implanted spinal cord stimulators in 25 patients who were refractory to medical therapies and not candidates for revascularization. All patients had a left ventricular ejection fraction greater than 30%. The team activated the stimulator in half of the patients and asked them to use it three times a day for an hour and, additionally, whenever anginal symptoms occurred. In the remaining control patients, the stimulator was not activated until the end of the study.
There were no complications in either treatment group and no dropouts. After six weeks, patients were able to exercise longer, and time to the onset of angina was significantly longer in the treatment group than in the control group.
Compared with the controls, at the end of the study, patients who received spinal cord stimulation took fewer sublingual nitrate tablets, had significantly fewer anginal attacks and ischemic episodes, and less ST-segment depression at comparable workloads.
Reference
1. Hautvast RWM, DeJongste MJL, StaalAm MJ, et al. Spinal cord stimulation in chronic intractable angina pectoris: A randomized, controlled efficacy study. Am Heart J 1998; 136:1,114-1,120.
ACC report: Statins are underprescribed
At least 20 million Americans at risk of heart attack aren’t being prescribed cholesterol-lowering drugs, and those who are may not be taking them, according to a report given at the annual meeting of the American College of Cardiology in New Orleans.
Even though the benefits of statins are now beyond dispute — they can reduce cholesterol levels by 60 points and taking them cuts the chances of heart attacks by a third — they are prescribed to only one in five of those who could benefit. And while only about half of heart attack patients are sent home from the hospital with prescriptions for the meds, patients themselves are to blame as well. They are often unenthusiastic about taking them, either because they underestimate their risk of heart trouble or they are reluctant to take drugs that don’t make them feel better right away. In addition, the medications are expensive — about $75 to $100 per month — and there are lingering concerns about their safety, although these have been largely put to rest.
Heated tip’ cath ablation moves to front line
An increasingly common operation in which surgeons burn away heart tissue to eliminate heart rhythm disturbances almost always succeeds and carries low risks, according to a recent study.1
The finding could encourage doctors to consider radio frequency catheter ablation over life-long drug treatment for patients with certain irregular heart rhythms, including those caused by congenital abnormal muscle connections, atrioventricular nodal re-entrant tachycardia, and problems at the atrioventricular junction that cause atrial fibrillation.
Catheter ablation was introduced a decade ago and has grown rapidly, with thousands now performed every year. The irregular heart rhythms treated by catheter ablation are usually not life-threatening, but cause palpitations that can frighten patients.
Researchers looked at about 1,000 patients at 18 hospitals who underwent catheter ablation. The arrhythmia disappeared in about 95%. A few needed repeated treatment, and 3% developed major complications, including three who died within a month of the surgery. The researchers said there was a 1% risk that a patient would eventually require a pacemaker.
In ablation, catheters with heated tips are threaded through blood vessels from the groin or an arm or leg into the heart, and the tips burn away tissue containing nerve pathways that cause the heart to misfire. Surgery generally costs $10,000 to $12,000, and is usually covered by insurance, although insurers frequently require that drugs be tried first.
Reference
1. Calkins H, Yong P, Miller JM, et al. Catheter ablation of accessory pathways, atrioventricular nodal reentrant tachycardia, and the atrioventricular junction. Circulation 1999; 99:262-270.
Does stress endurance equal good health?
The treadmill has been the bellwether for cardiovascular fitness: If a patient can run on the machine for more than about nine minutes, he’s considered to be in pretty good shape. That was so until recent research suggesting that, at least for some patients, the stress test may be a poor judge of future heart problems.1
Researchers at Baylor College of Medicine in Houston looked at nearly 390 patients, 83% percent of whom had a history of heart trouble. The researchers gave the subjects treadmill tests — exercise EKGs — then myocardial perfusion imaging (MPI). Beyond gauging endurance, MPI shows blood flow back to the heart and is a good way to look at the system’s inner workings.
Running with heart disease
While more than 75% of the patients ran for nine minutes or longer without a problem, about 40% had abnormal circulation as measured by MPI. Moreover, 224, or 57%, showed signs of heart disease. Nearly 20 underwent bypass surgery as a result of the screening tests.
Patients with abnormal MPI readings were about eight times more likely to suffer heart trouble within the next 18 months as were those who had normal blood flow — regardless of their ability to jog on the treadmill. Heart problems cropped up in about 6% of patients who failed their exercise EKG, almost the same as in those who did well on the machine.
"Just the fact that the patients are going [for a long time] on the treadmill doesn’t mean they are healthy," say researchers.
Reference
1. Chatziioannou SN, Moore WH, Ford PV, et al. Prognostic value of myocardial perfusion imaging in patients with high exercise tolerance. Circulation 1999; 99:867-872.
Suggested Reading
Shephard RJ, Balady GJ. Exercise as cardiovascular therapy. Circulation 1999; 99:963-972.
AMI severity declining
The severity of heart attacks is apparently declining, according to a Wake Forest University School of Medicine (Winston-Salem, NC) researcher presenting at the most recent American Heart Association Conference on Cardiovascular Disease Epidemiology and Prevention in Orlando, FL.
He attributed possible reasons for the decline to increased preventive measures, such as blood pressure and cholesterol control, and better treatment options. Results from the long-running Atherosclerosis Risk in Communities (ARIC) study show that both in-hospital and out-of-hospital coronary heart disease mortality decreased over the last several years, and that the average size of the infarct decreased as well.
Of 16,000 participants involved in the ARIC study, researchers focused on 3,550 first heart attacks. While EKGs showed an increase in severity, a measure based on blood enzymes showed declining severity, and a third measure based on abnormal pulse rate and abnormally low systolic blood pressure showed little change. The results from the severity indicators are somewhat inconsistent but on the whole, concluded the researchers, "they point to a lessening in the severity of hospitalized heart attack patients."
104 new heart meds are on the table
Just under 70 pharmaceutical and biotechnology companies are developing 104 new medicines for heart disease and stroke, according to a survey by Washington, DC-based Pharmaceutical Research and Manufacturers of America (PhRMA). The drugs, now either in clinical trials or awaiting approval by the Food and Drug Administration, include:
• 11 for angina;
• seven for arrhythmia;
• 19 for congestive heart failure;
• 12 for heart attack;
• nine for high cholesterol;
• 10 for high blood pressure;
• 21 for stroke.
Several of the potential drugs make use of cutting-edge technologies. For example, gene therapies are being tested to prompt the heart to grow new blood vessels, bypassing clogged arteries. A clot buster now in testing shows promise of doubling the window of time for preventing brain damage. A genetically engineered form of a hormone that bolsters a failing heart is being developed as a short-term treatment for congestive heart failure. And a new drug for atrial fibrillation has been shown to prolong the periods in which patients with this condition are free of abnormal heart rhythm. For more information, access PhRMA at www.phrma.org.
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