Use B-type natriuretic peptide test in preparticipation exam.
WASHINGTON -- Physicians should consider using B-type natriuretic peptide to screen for hypertrophic obstructive cardiomyopathy in patients who present for a preparticipation physical examination.
The test is cheaper than an echocardiogram and could prevent sudden cardiac death in otherwise healthy young athletes, Dr. Suraj Achar said at the annual meeting of the American Academy of Family Physicians.
B-Type natriuretic peptide (BNP) is one of four known natriuretic peptides released from the ventricles during pressure or volume overload. It has been used primarily in patients with chronic heart failure to assess their risk of death or other complications. A level of less than 100 pg/mL is normal; 500 pg/mL is the goal for heart failure patients at hospital discharge; and 700 pg/mL or more is indicative of decompensated congested heart failure.
Hypertrophic obstructive cardiomyopathy (HOCM) is a genetic condition that affects 1 in 500 people, most of whom are asymptomatic. In about 70% of patients, the condition goes undetected until it is pathologic.
The prognostic value of a BNP test to screen for the condition is based on heart failure data that have shown that BNP levels are elevated whenever there is a stretch on the myocardium, said Dr. Achar, a professor at the University of California, San Diego.
"That's the same thing in a way that happens with HOCM: You get hypertrophy of the myocardium that we believe will show up with an elevated BNP, even when the patients are clinically asymptomatic or normal on physical exam," he said in an interview.
Dr. Achar and the study's principal investigator, Dr. Alan Maisel, a cardiologist at the university, have screened 500 high school and college athletes for HOCM using a BNP assay as part of a preparticipation physical exam conducted by the university's sports medicine program. Of those, five patients had elevated BNP levels, with the highest being 100 pg/mL.
All of the patients had negative echocardiograms and are being followed.
One of the motivations for the study was a young man who was identified with HOCM but who didn't heed the advice of his physicians and died of sudden cardiac arrest after a pick-up game of basketball.
"[We aim] to prevent sudden deaths in these patients and to get them in the hands of a cardiologist for definitive treatment," he said. Echocardiogram would provide a definitive diagnosis of HOCM, but it is not cost effective when used as a screening tool in all U.S. athletes, he said.
The Heart Failure Society of America's latest guidelines on the evaluation and management of heart failure recommend using echocardiogram only when heart failure is suspected but diagnosis is uncertain.
Dr. Achar also advocates using BNP to screen for hypertrophic cardiomyopathy in patients who present with exertional dizziness.
"Their level may not be florid like a 400 [pg/mL], but it's going to be 100 [pg/mL], 150 [pg/mL], and that might tip us off that this is not a normal case of dizziness and to get an echocardiogram," Dr. Achar said.
BY PATRICE WENDLING
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|Title Annotation:||Clinical Rounds|
|Article Type:||Disease/Disorder overview|
|Date:||Feb 1, 2007|
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