Prognostic value of the collagen volume fraction in hypertrophic cardiomyopathy.
BACKGROUND
In hypertrophic cardiomyopathy (HCM), interstitial myocardial fibrosis is an important histological modification that has been associated with sudden death and evolution toward myocardial dilation.


OBJECTIVE
To prospectively evaluate the prognostic value of the collagen volume fraction in HCM.


METHODS
An endomyocardial biopsy of the right ventricle was successfully performed in 21 symptomatic patients with HCM. The myocardial collagen volume fraction (CVF) was determined by histology. The CVF was also determined in fragments of nine normal hearts from subjects deceased from non-cardiac causes. The patients were divided into above-median CVF and below-median CVF groups, and their clinical and echocardiographic characteristics and survival curves were compared.


RESULTS
Among the patients, the CVF ranged from 1.86% to 29.9%, median 6.19%; in normal hearts, from 0.13% to 1.46%, median 0.61% (p <0.0001 between HCM and control). There were no significant correlations between CVF and baseline echocardiographic measures. Patients with CVF < or =6.19% and CVF> 6.19% were compared and no baseline differences were observed. However, after an average follow-up period of 110 months, four deaths occurred (two sudden, two due to heart failure) in the group with increased CVF, whereas the patients of the group with lower CVF were all alive at the end of the period (p = 0.02).


CONCLUSIONS
For the first time, myocardial fibrosis was prospectively associated with a worse prognosis in patients with HCM. Efforts should be directed to the quantification of myocardial fibrosis in HCM, on the premise that its association with the prognosis can aid in the stratification of risk for defibrillator implantation, and in the prescription of drugs that potentially promote myocardial repair.
Arteaga
Edmundo
E
Instituto do Coração, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, SP, Brasil. edmundo.arteaga@incor.usp.br
de Araújo
Aloir Queiroz
AQ
Bernstein
Mauricio
M
Ramires
Felix J A
FJ
Ianni
Barbara Maria
BM
Fernandes
Fabio
F
Mady
Charles
C
D000293:Adolescent; D000328:Adult; D002312:Cardiomyopathy, Hypertrophic / Q000150:complications / Q000175:diagnosis* / Q000401:mortality; D003094:Collagen / Q000032:analysis; D016757:Death, Sudden, Cardiac / Q000209:etiology; D004812:Epidemiologic Methods; D005260:Female; D005355:Fibrosis; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology*; D011379:Prognosis; D055815:Young Adult
D003094:Collagen