Heart News and Notes

Actos (rosiglitazone) and Avandia (pioglitazone) are two drugs in the class called thiazolidinediones (TZDs) used to lower blood sugar in patients with diabetes. Studies have found that Avandia, but not Actos, increases the risk of heart attack and heart failure.

The New York Times reported last month that a “fierce debate” is going on in the Food and Drug Administration (FDA) between some officials who want Avandia pulled from the market and others who say the studies are contradictory and inconclusive. The Senate Finance Committee released a report last month criticizing GlaxoSmithKline and the FDA for failing to warn patients of the risk.

Then the American Heart Association and the American College of Cardiology jointly issued an advisory, saying the data is inconclusive. It said the first choice drug should be metformin, and if a TZD is used it should not be expected to lower heart risk.

Blood volume increases about 50 percent during pregnancy to provide for the placenta and the fetus. In the month before or a few months after childbirth the increased stress on the heart can cause a rare condition called peripartum cardiomyopathy, in which the heart becomes stiff and enlarged and can’t pump effectively. About half the patients recover spontaneously but some cases are fatal.

A small study in a hospital in Georgia found that the number of cases per 100,000 pregnancies was 24 for non-blacks but 340 for African-Americans. Other risk factors didn’t account for the racial disparity. African-American women are also at higher risk for preeclampsia, a dangerous blood pressure rise late in pregnancy.

Recent articles in these pages have looked at how long Plavix (clopidogrel) should be continued after a drug coated stent is implanted. The consensus now seems to be that one year is enough, and the focus now is on how, not when, the drug should be discontinued.

Previous studies found cardiac events to be more likely right after stopping Plavix, suggesting a “rebound” in the tendency to form blood clots that could cause heart attacks. A small study of 69 patients in Germany, published last month, randomly assigned 69 patients to either continue for four more weeks or taper the dosage off during that time, and the peak platelet aggregation (clumping) was measured during the next four weeks.

There was no significant difference between the two groups. The results suggest that tapering off the dosage is unnecessary.

For the last quarter century researchers have been trying to make use of a puzzling phenomenon called ischemic conditioning. Depriving an organ of oxygen for brief periods can protect it against damage from later prolonged deprivation. Patients suffer less damage from heart attack if they have had a previous heart attack. Oxygen deprivation in one part of the body can even protect other parts.

In a study in Denmark reported last month, heart attack victims were randomly assigned to have standard care during transport to the hospital, or to have a blood pressure cuff inflated to stop blood flow in one arm four times for 5 minutes each time. Patients treated with the cuff had significantly less heart damage, especially when a coronary artery was completely occluded or the LAD (left anterior descending) artery was affected.

Another article published last month reported progress in studying the mitochondrial ATP-sensitive potassium channel, or mKATP, believed to be active in ischemic conditioning. The goal is to protect the heart chemically without actual oxygen deprivation.

A report by the Institute of Medicine (IOM) calls high blood pressure a “neglected disease” that should be treated, not as a problem for individual patients, but as a public health issue requiring action at all levels of government. The American Heart Association praised the report; the Salt Institute panned it.

A large majority of people ingest too much sodium and not enough potassium. Patients skip blood pressure medications because of their high cost. Physicians don’t consistently follow guidelines for blood pressure screening and treatment.

Population-wide reduction in salt is named as a priority. Most salt is added in food processing before consumers even see the food. A combination of sodium and potassium chloride could reduce sodium while increasing potassium. Another priority is lowering the cost of medications for hypertension.

Physicians should tell patients over 40 their global risk for coronary artery disease, and use it to kick off health discussions, according to American Heart Association guidelines. But there is little evidence of how effective that is.

A recent review of 20 previous articles found that telling patients several times is more effective than telling them once, adding education is even more effective, and adding counseling to education makes it still more effective. The differences are small but significant.

Editor’s note: physicians are quick to blame the patient for failing to comply with treatment, but it might be time for patients to blame the physicians. Patients have other concerns besides their disease risk and are seldom eager to break old habits. Physicians should understand this and make a greater effort, for the sake of the patient’s health, to deliver the message.