title: Frequency, Mechanism and Severity of Mitral Regurgitation: Are There any Differences Between Primary and Secondary Mitral Regurgitation?
abstract: Although mitral regurgitation (MR) is a well-recognized prognosis factor, its true prevalence is probably underestimated and its etiology and mechanisms have not been sufficiently explored. The study aim was to evaluate the burden of MR, focusing attention on its frequency, severity, etiology, mechanism, and other associated conditions.
  
  
  
  Between February and June 2015, a total of 39,855 consecutive echocardiographic studies was performed at nine tertiary hospitals, and were prospectively included in the study. MR severity was graded into four groups, ranging from none or trace to severe MR, in accordance with the recommendations of the European Association of Cardiovascular Imaging. Patients with moderate to severe MR were selected for the analysis.
  
  
  
  MR was detected in 22.6% of cases. MR severity was mild in 82.5% of patients (n = 7,376), moderate in 11.7% (n = 1,048), and severe in 5.8% (n = 521). Concomitant valvular heart disease was present in 3,544 patients (39.7%), with tricuspid regurgitation the most frequently encountered (21.6%). Among moderate and severe MR, primary MR was more frequent than secondary MR (58.8% versus 23.5%), with degenerative valve disease being the most common cause of primary MR (49.2%). A third group composed of mixed forms of MR was described in 17.8% of cases.
  
  
  
  MR is a common finding on echocardiography, and is frequently associated with other valvular heart disease. Most MRs are of degenerative origin. The primary and secondary forms of MR differ significantly in their clinical presentation with regard to gender, age, and ventricular function. There appears to be a gap for a 'mixed' group, though further studies are needed to confirm this suggestion.
authors.affiliation: University Alcala de Henares, Hospital Ramon y Cajal, Carretera de Colmenar Km 9.100, Madrid, Spain Electronic correspondence: zamorano@secardiologia.es.
authors.forename: José L
authors.initials: JL
authors.lastname: Zamorano
authors.affiliation: University Alcala de Henares, Hospital Ramon y Cajal, Carretera de Colmenar Km 9.100, Madrid, Spain.
authors.forename: Juan
authors.initials: J
authors.lastname: Manuel Monteagudo
authors.affiliation: Cardiology Department, Hospital Reina Sofia, Cordoba, Spain.
authors.forename: Dolores
authors.initials: D
authors.lastname: Mesa
authors.affiliation: Cardiology Department, Hospital General Universitari Vall d'Hebron, Barcelona, Spain.
authors.forename: Teresa
authors.initials: T
authors.lastname: Gonzalez-Alujas
authors.affiliation: Cardiology Department, Thorax Institute, Hospital Clinic, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), University of Barcelona, Spain.
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.affiliation: Cardiology Department, Hospital Virgen de la Victoria, Malaga, Spain.
authors.forename: Fernando
authors.initials: F
authors.lastname: Carrasco-Chinchilla
authors.affiliation: Cardiology Division, Department of Medicine, Hospital de Sant Pau I de la Santa Creu, Universidad de Barcelona, Barcelona, Spain.
authors.forename: Chi-Hion
authors.initials: CH
authors.lastname: Li
authors.affiliation: Cardiology Department, Hospital Virgen del Rocío, Sevilla, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Grande-Trillo
authors.affiliation: Cardiology Department, Hospital Clinico Santiago de Compostela, A Coruña, Spain.
authors.forename: Amparo
authors.initials: A
authors.lastname: Martinez
authors.affiliation: Cardiology Department, Hospital Virgen del Rocío, Sevilla, Spain.
authors.forename: Javier
authors.initials: J
authors.lastname: Matabuena
authors.affiliation: Cardiology Department, Hospital de León, León, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Alonso-Rodriguez
authors.affiliation: University Alcala de Henares, Hospital Ramon y Cajal, Carretera de Colmenar Km 9.100, Madrid, Spain.
authors.forename: Covadonga
authors.initials: C
authors.lastname: Fernandez-Golfin
mesh_terms: D000368:Aged; D004452:Echocardiography; D005260:Female; D006349:Heart Valve Diseases / Q000150:complications; D006801:Humans; D008297:Male; D008944:Mitral Valve Insufficiency / Q000150:complications / Q000000981:diagnostic imaging* / Q000453:epidemiology / Q000209:etiology*; D015995:Prevalence; D011446:Prospective Studies; D012720:Severity of Illness Index