Discharging PCI Patients Early
A special scoring system used to identify patients at low risk of cardiac events after primary percutaneous intervention could save patients time in the hospitals and reduce healthcare costs, said researchers from ISALA Klinieken, Hospital De Weezenlanden, Zwolle, The Netherlands, in a report in this week’s issue of the journal Circulation (Circulation. 2004;109:2737–2743OpenUrl).
The prognostic scoring system was developed by the researchers, led by Giuseppe De Luca, MD, of Hospital De Weezenlanden, Zwolle, The Netherlands, on the basis of 30-day mortality rates in 1791 patients who had undergone primary angioplasty for ST-segment–elevation myocardial infarction. Predictors of death within 30 days included age, anterior infarction, Killip class, ischemic time, postprocedural Thrombolysis in Myocardial Infarction (TIMI) flow, and multivessel disease. Using this score, the researchers identified 73.4% of patients as having a low risk. Those with a low risk could be discharged early, with care being shifted to an outpatient setting between 48 and 72 hours. Among those patients considered low risk, the mortality rate was 0.1% at 2 days and 0.2% between 2 and 10 days.
The researchers concluded that the scoring system could aid in clinical decisions while lowering the cost of care delivered to such patients without endangering their lives.
Building Hearts Anew
Houston, Tex—Everything discussed at the recent symposium on “The Implantable Left Ventricular Assist Device: From Concept to Clinical Reality” sponsored by the Texas Heart Institute in Houston, Tex, did not revolve around textured surfaces and titanium construction.
Dissatisfaction with the status of heart failure therapy and older left ventricular assist devices led James T. Willerson, MD, President of The University of Texas Health Science Center at Houston, to begin to look at using stem cells to repair injury to heart. “From the union of our fathers’ sperm and our mothers’ eggs every one of us became what we are today and what we aren’t,” he said. “That’s a stem cell phenomenon.”
His first clinical work with bone marrow–derived stem cells was done at Pro-Cardiaco Hospital in Rio de Janeiro, Brazil, in collaboration with Emerson Perin, MD, Director of New Interventional Cardiovascular Technology at the Texas Heart Institute, Dr Hans Dohmann, and Brazilian researchers. In their first study 3 years ago, they treated 14 patients with their own bone marrow–derived stem cells delivered directly into the heart muscle using a NOGA catheter. They were compared with 7 controls who received best medical therapy. They found that the treated patients had an improvement in New York Heart Association functional class and in Canadian Classification System class. They demonstrated an increase in treadmill exercise capacity and maximal O2 consumption. There was an improvement in end-systolic volume and LV ejection fraction. At both 2 and 4 months later, they could see an improvement in blood flow at the site of previous ischemia.
“Would we like to use fetal cells? We certainly would,” said Dr Willerson. “They probably would have greater differentiation capability.” Nevertheless, using the cells they have used already, they have found that the benefit is sustained for at least a year. He cautions, however, that the period of follow-up remains short and that none of the studies done by him or others in the field have been double-blind or randomized.
“We have gotten the FDA [US Food and Drug Administration] to agree to a randomized study,” he said. That study is already underway in the United States at the Texas Heart Institute and St Luke’s Episcopal Hospital in Houston, Tex.
“I think stem cells will be a vector for gene delivery,” Dr Willerson said. Genes for antioxidants, genes to promote angiogenesis, and genes to restore the function of cellular ion pumps and receptors possibly could be delivered by this technique.
The future is bright and the areas currently under study are varied, he said. “In the future, I predict that hearts will be cloned from one’s own stem cells. It will be a while, but it will happen.”
Alterations in myocytes, the myocardium, and left ventricular geometry go together to effect the reverse remodeling occasionally seen after implantation of a left ventricular assist device (LVAD), said Douglas Mann, MD, Professor of Internal Medicine (Cardiology) at Baylor College of Medicine.
During heart failure, said Dr Mann, the myocytes hypertrophy with important changes in the cytoskeletal proteins. On the LVAD, “the myocytes actually get smaller. Is this a good thing? It’s probably a good thing,” he said.
In the laboratory, when you stimulate myocytes from a heart in failure, the contraction is decreased, he said. “The extent of contraction is better after the LVAD, with brisker excitation and relaxation.”
The failing heart loses actin and myosin filaments that are important to strong cells, he said. After support with the LVAD, the cells begin to regrow actin and myosin filaments.
Also, he said, after LVAD support, there is an increase in β-adrenergic receptors that were lost during heart failure. In addition, some of the cytoskeletal defects seen in the failing heart are reversed after LVAD implantation.
Altogether, he said, the left ventricle improves with LVAD support.