CHICAGO — Newly issued guidelines seek to standardize valve surgery, improve the quantification of valve lesions, and involve patients in their management.
Released at a meeting sponsored by the American College of Cardiology, the Guidelines for the Management of Patients with Valvular Heart Disease recommend the widespread use of echocardiography and Doppler imaging, according the chairman of the guideline writing committee, Dr. Robert O. Bonow.
The 148-page document is the first revision of the practice guidelines of the ACC and the American Heart Association, originally released in 1998.
“What the guidelines are attempting to do is to move the field into a more objective and quantitative approach, and there are ways to do this with Doppler imaging, which many laboratories are not doing,” said Dr. Bonow, chief of the division of cardiology at Northwestern University in Chicago.
“We do not want echocardiography and Doppler cardiograms being interpreted only qualitatively. If valve regurgitation appears to be severe, it should be measured so that the severity can be quantitatively demonstrated,” he said in an interview.
Committee members who presented the guidelines at the meeting emphasized several issues:
▸ Aortic stenosis. The basic guidelines for aortic stenosis remain largely unchanged, but the revision clarifies the definition of “severe” asymptomatic aortic stenosis and states that adults with this diagnosis may be considered for valve replacement if there is a high likelihood of rapid progression or if surgery might be delayed at the time of symptom onset.
Also new is the recommendation that aortic valve replacement may be considered in patients undergoing coronary artery bypass grafting who have mild AS when there is evidence that progression may be rapid.
When valve replacement is considered, watchful waiting is advised, because there's no evidence in the literature that a benefit can be derived from performing valve replacement in the absence of symptoms, the new guidelines state.
▸ Aortic regurgitation. In recognition of the relatively benign course of lone asymptomatic aortic regurgitation, the committee recommended against valve repair or replacement in patients with normal left ventricular systolic function at rest. “Surgery is reasonable for patients with very large ventricles who may be at risk for sudden cardiac death,” said committee member Dr. Patrick T. O'Gara.
Aortic valve repair or replacement also is indicated for symptomatic patients with severe aortic regurgitation irrespective of left-ventricular systolic function, and in those with severe AR who have a need to undergo cardiac or aortic surgery, explained Dr. O'Gara of the Harvard Medical School in Boston.
▸ Mitral regurgitation. Two themes emerge in the guidelines for mitral regurgitation, emphasizing the need for valve repair and earlier surgery. “The committee is trying to direct the trend more toward valve repair and away from valve replacement,” said committee member Dr. Blase A. Carabello, vice chairman of the department of medicine at the Baylor College of Medicine in Houston, explaining that studies show that repair has survival advantages over replacement.
Another issue involves valve selection—mechanical or bioprosthetic—for those requiring replacement. The cutoff age of 65 for the use of bioprosthetic valves was liberalized to the advantage of younger patients who wish to avoid the use of blood-thinning drugs, Dr. Bonow explained. The patient should understand that, with a bioprosthetic valve, there's a high likelihood of the need for a second operation later on, he stressed.
The guidelines also clarify the use of blood thinners in pregnancy, recommending continuous anticoagulation in all pregnant women with mechanical prosthetic valves. Up to 36 weeks' gestation, the therapeutic choice of continuous dose-adjusted or intravenous subcutaneous unfractionated heparin, dose-adjusted low-molecular-weight heparin, or warfarin should be discussed fully.
The 2006 guidelines can be viewed online at www.acc.orgwww.myamericanheart.org
The guidelines are attempting 'to move the field into a more objective and quantitative approach.' DR. BONOW