Heart News and Notes

Death rates from heart disease and stroke continue to decline, according to a year-end statistical report in last month’s Circulation compiled from death certificates in 2006 and 2007 (the latest available) by the American Heart Association. But death rates went up slightly in younger adults, particularly women age 35 to 54, warning of worse to come.

Worse to come is also forecast by rising risk factors. More people - including children - are obese, and more have diabetes. Average cholesterol levels have gone down in older adults but not in younger adults. Couch potatoes abound; exercise is rare.

The report suggests that the declining death rates are due to better treatment of more disease, which we might not be able to keep up with, and therefore calls for sharper focus on prevention, not just treatment.

Last Spring a few articles mentioned that Plavix, a drug used to prevent blood clots that could block an artery, could be inactivated by proton pump inhibitors prescribed to protect the stomach from bleeding due to Plavix. Last month a few more warnings surfaced.

Celebrex (celecoxib), a COX-2 inhibitor prescribed to relieve arthritis symptoms without irritating the stomach, could block the clot-preventing effect of “baby” (81mg) aspirin unless taken about half an hour after the aspirin. Full strength (325mg) aspirin is not affected.

MRI scanning could interfere with a pacemaker. The experimenters probed the electric fields near pacemaker leads in a saline tank, using a few lead types and a simulated scanner. They recommend using the same method to test different leads with a real scanner.

Some clot-buster drugs should not be used for dialysis patients because they depend on kidney function to be cleared from the body. But about one in five dialysis patients getting PCI (angioplasty or stents) were given these drugs, sometimes causing serious bleeding.

Two months ago in this spot had an article headlined “One Year Is Not Enough...” with a warning that even the study author wasn’t sure. A review article published last month in the Journal of the American College of Cardiology concluded that after implantation of a drug-coated stent, one year of dual antiplatelet therapy - Plavix plus aspirin - is enough, considering the risk of bleeding, to limit the risk of a clot blocking the stent.

That conclusion is based on the body of data available now. Two very large studies are underway that, when completed, could change the recommendation again.

Current guidelines for coronary artery disease patients call for exercise at 50 to 80 percent of capacity for 20 to 60 minutes three to five times a week. A recent study in Norway compared that routine with more strenuous interval training in forty patients who had just had a stent implanted.

Half the patients, the test group, exercised for one hour, three times a week, warming up for ten minutes and then alternating 4 minutes of exercise to 80 to 90 percent of maximum heart rate with 3 minute periods of recovery at 60 to 70 percent of maximum. The rest, as a control group, followed the guidelines.

After six months the test group had significantly less restenosis (narrowing of the artery inside the stent). Other risk factors, including C-reactive protein (a measure of inflammation), were also better.

Losing less than 10 percent of their weight reversed some of the effects of obese patients’ bulk in a study published last month. On either low-fat or low-carb diets, they improved their heart function and reduced their left ventricular mass and carotid artery wall thickness. Some improvement remained even after they regained some of their lost weight. Since both diets helped, the improvement was likely due to the weight loss. The study did not show which diet was better and did not look for reductions in heart disease events.

Another study looked at smoking and its effect on survival over about 13 years after a first heart attack. Smokers who quit before the heart attack had 50 percent less risk of dying; quitting after the heart attack lowered the risk by 37 percent. Even just cutting back helped. Another study, using laboratory rats, showed that light to moderate smoking before a heart transplant, either by the donor or the recipient, raised the risk of losing the transplanted heart by about one-third.

Population-wide, lower smoking rates would increase average life expectancy over the next decade by about three years, according to yet another study, but an expected increase in obesity will outweigh it, netting about seven months decrease. Individually, smoking outweighs weight, but obesity is more widespread.

Vitamin D was discussed at the American Heart Association 2009 Scientific Sessions last November. A new report found that very low levels of vitamin D were associated with 45 percent more coronary artery disease, and 78 percent more stroke, than normal levels. Since this was an observational study, cause vs. effect is not clear. Two large randomized trials are underway.

Vitamin D comes from sunlight and diet. Risk factors for deficiency include dark skin, staying indoors, and winter. Fish helps.

A study published last month found that people with high blood pressure are twice as likely to have congestive heart failure if they have a gene variant that interferes with the activation of vitamin D.