MONDAY, June 3 (HealthScoutNews) -- The cholesterol-lowering drugs known as statins could have yet another health benefit for the heart: Animal research suggests they can treat the early stages of a disease that strikes the organ's plumbing.
There is no drug therapy for the disease, in which skeletal bone structures grow in the valve. The best doctors can do is replace the valves once the disease reaches its later stages.
"Valve replacement is the only option," says Dr. Daniel Fisher, a cardiologist and clinical assistant professor at New York University Medical Center. "It's effective, but it's major cardiac surgery and it occasionally requires a lifelong blood thinner if the replacement is a metal valve."
Part of the reason for the lack of effective therapies is a lack of information on the cellular causes of aortic valvular disease. This study, appearing in tomorrow?s issue of Circulation, appears to be the first to explain the specific cellular mechanisms behind the disease.
"Up until now, people really thought it was a wear-and-tear phenomenon," says Dr. Nalini Rajamannan, study author and assistant professor of cardiology at Northwestern University. "They didn't realize the valve itself has its own biology." The Northwestern team worked jointly on the study with researchers at the Mayo Clinic.
The aortic valve, one of four in the heart, opens and shuts like a faucet to let blood flow to the aorta -- the huge artery in the middle of your body -- from one of the chambers called the left ventricle. In aortic valve disease, the valve doesn't open or shut properly.
People with aortic valve disease have many of the same risk factors as people with vascular atherosclerosis, namely smoking, male gender, hypertension and high cholesterol levels.
This similarity led the researchers to hypothesize that some of the same processes were at work in both conditions. Using a rabbit model, they discovered that animals with the valve disease displayed both atherosclerosis and bone gene expression that was similar to that found in the skeleton.
This is how the process seems to work: High cholesterol levels lead to the buildup of fatty deposits in the aortic valve. These deposits, in turn, may prompt certain undifferentiated cells to transform into bone-forming cells that calcify and narrow the valve.
The researchers are seeing similar changes in human valves salvaged from replacement surgery.
The most exciting part of the study, though, is that the problem appears to have a solution: Statins reduced the buildup of bone formations and slowed the progression of the disease in animals. This could delay the need for valve replacement surgery if the disease is caught in the early stages.
"We are getting more aggressive in using cholesterol-lowering medicine to treat coronary artery disease," Fisher says. "This study would give us a reason to use medicine to prevent valvular disease. It's pretty radical."
There are more hoops to jump through before statins become an accepted therapy for aortic valve disease. In particular, Rajamannan and her colleagues are hoping to initiate a large-scale clinical trial to investigate the effectiveness of statins in people with early valve lesions, often a risk factor for aortic valve disease. These lesions are easily detected in a doctor's office without sophisticated equipment.
The research is early, so don't expect your doctor to prescribe statins yet to ward off this disease, which can also be congenital.
What To Do
The American Heart Association has more information on both valve disease and cholesterol-lowering drugs.
SOURCES: Daniel Fisher, M.D., clinical assistant professor, New York University Medical Center, New York City; Nalini Rajamannan, M.D., assistant professor, cardiology, Feinberg School of Medicine, Northwestern University, Chicago; June 4, 2002, Circulation~HICH~~HRTS~