Features January 2011 Issue

Women Recover from Aortic Valve Surgery More Quickly than Men

Research shows that womenís hearts shrink back to a healthier size after surgery at a faster rate than menís hearts after the same operation.

A stiff aortic valve (stenosis) can cause a condition called left ventricular hypertrophy, in which the walls of the heartís primary pumping chamber enlarge. This occurs when the heart muscle is forced to overwork as it struggles to pump. Unlike a large bicep, which makes you stronger, however, an overworked heart muscle can become stiff and weak, leading to heart failure.

Aortic valve replacement surgery can involve either a mechanical or biological valve.

After the aortic valve is replaced, the heart muscle begins to shrink back to its normal size and shape. A study of nearly 100 male and female aortic valve surgery patients, published in the September 14, 2010 issue of Circulation, found that this desirable effect occurs much faster in women than in men. After valve replacement surgery, half the women in the study showed noticeable regression in as little as three days. Over time, the size of their left ventricle continued to regress faster in women, leaving only 12 percent of women, but 34 percent of men, with hypertrophy at the end of the study.

The authors found an underlying reason at the molecular level that may explain the difference in gender response. In response to the stress of extra work, menís heart muscles developed tough proteins that caused fibrosis. This results in higher levels of fibrous tissues in the heart after surgery.

Rat studies have shown that estrogen protects against these changes. The presence of estrogen enabled the womenís hearts to revert to normal shape more quickly once the stressor (a stenotic heart valve) was removed.

Researchers hope that this study and future studies that may replicate these findings will lead to treatments that can help slow the growth of fibrous tissues in the after the development of aortic stenosis.

The study also revealed that a higher percentage of women experienced left ventricular hypertrophy than men did prior to surgery. In addition, more women in the study than men had thyroid disease, which can contribute to an enlarged heart.