Natural history of asymptomatic mitral valve prolapse in the community.
BACKGROUND
The outcome of mitral valve prolapse (MVP) is controversial, with marked discrepancies in reported complication rates.


RESULTS
We conducted a community study of all Olmsted County, Minn, residents first diagnosed with asymptomatic MVP between 1989 and 1998 (N=833). Diagnosis, motivated by auscultatory findings (n=557) or incidental (n=276), was always confirmed by echocardiography with the use of current criteria. End points analyzed during 4581 person-years of follow-up were mortality (n=96, 19+/-2% at 10 years), cardiovascular morbidity (n=171), and MVP-related events (n=109, 20+/-2% at 10 years). The most frequent primary risk factors for cardiovascular mortality were mitral regurgitation from moderate to severe (P=0.002, n=131) and, less frequently, ejection fraction <50% (P=0.003, n=31). Secondary risk factors independently predictive of cardiovascular morbidity were slight mitral regurgitation, left atrium > or =40 mm, flail leaflet, atrial fibrillation, and age > or =50 years (all P<0.01). Patients with only 0 or 1 secondary risk factor (n=430) had excellent outcome, with 10-year mortality of 5+/-2% (P=0.17 versus expected), cardiovascular morbidity of 0.5%/y, and MVP-related events of 0.2%/y. Patients with > or =2 secondary risk factors (n=250) had mortality similar to expected (P=0.20) but high cardiovascular morbidity (6.2%/y, P<0.01) and notable MVP-related events (1.7%/y, P<0.01). Patients with primary risk factors (n=153) showed excess 10-year mortality (45+/-9%, P=0.01 versus expected), high morbidity (18.5%/y, P<0.01), and high MVP-related events (15%/y, P<0.01).


CONCLUSIONS
Natural history of asymptomatic MVP in the community is widely heterogeneous and may be severe. Clinical and echocardiographic characteristics allow separation of the majority of patients with excellent prognosis from subsets of patients displaying, during follow-up, high morbidity or even excess mortality as direct a consequence of MVP.
Avierinos
Jean-François
JF
Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minn 55905, USA.
Gersh
Bernard J
BJ
Melton
L Joseph
LJ
Bailey
Kent R
KR
Shub
Clarence
C
Nishimura
Rick A
RA
Tajik
A Jamil
AJ
Enriquez-Sarano
Maurice
M
D000368:Aged; D002318:Cardiovascular Diseases / Q000453:epidemiology / Q000209:etiology / Q000401:mortality; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D008945:Mitral Valve Prolapse / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000401:mortality; D011379:Prognosis; D012307:Risk Factors; D015996:Survival Rate; D014463:Ultrasonography