Johns Hopkins researchers say a heart imaging study of scores of pregnant women with the most severe and dangerous form of a blood pressure disorder has added to evidence that the condition -- known as preeclampsia -- mainly damages the heart's ability to relax between contractions, making the organ overworked and poor at pumping blood.

Preeclampsia is a condition marked primarily by high blood pressure and organ damage. It occurs in an estimated 5 to 8 percent of pregnant women, and in developing countries it causes up to 60 percent of all maternal deaths as well as premature births. In recent decades, researchers have been aware that preeclampsia also significantly increases the risk of heart failure, heart attack and stroke in mothers who had it but recovered -- just how and why this risk occurs has been unclear.

In the new study, designed to shed light on the subject, the Johns Hopkins researchers used imaging technology to study the pumping and relaxing activity of hearts in the sickest 10 percent of pregnant women with preeclampsia. A report on the study was published in the Journal of the American College of Cardiology on July 2.
"Although we have ways of identifying and managing risk factors in many women, severe preeclampsia sometimes hits the healthy without warning," says Arthur Jason Vaught, M.D., assistant professor of gynecology and obstetrics at the Johns Hopkins University School of Medicine. "If we can find the causes and mechanisms behind the disorder, the idea is that we find better ways to prevent and treat it."

Because Johns Hopkins treats many high-risk pregnancies, the researchers were able to identify 63 women with severe preeclampsia for their study, along with 36 healthy matched controls. They defined severe preeclampsia as having a blood pressure higher than 160/110; abnormal levels of protein in the urine reflecting kidney damage; diagnosed kidney or liver damage; fluid in the lungs; low platelet counts and/or vision problems. Study participants had an average age of 30; 47 percent were African-American, 44 percent were white, 9 percent were Hispanic and 4 percent were Asian.

All participants underwent echocardiography to make images of the heart's chambers at about 33 weeks of pregnancy. Results of the imaging showed that women with severe preeclampsia had higher contraction pressures in the right ventricles of their heart, and an average 31 millimeters of mercury compared to the healthy group with 22 millimeters of mercury. The ventricles are the two lower pumping chambers of the heart's four sections.

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