title: Circulating plasma and platelet 5-hydroxytryptamine in carcinoid heart disease: a pilot study.
abstract: OBJECTIVE
  Carcinoid heart disease (CaHD) is a rare form of valvular heart disease in patients with carcinoid syndrome (CS). The role of 5-hydroxytryptamine (5-HT) in the pathogenesis of CaHD is unclear. The study aim was to evaluate the association between platelet 5-HT (5-HTplt) and plasma 5-HT (5-HTpls) and valvular dysfunction.
  
  
  METHODS
  Twelve patients with CaHD, 18 with CS and 10 'normal' subjects were recruited. Patients with CaHD underwent cardiac catheterization and echocardiography. 5-HTplt and 5-HTpls was sampled in blood from the femoral vein, right and left ventricle, and left antecubital fossa vein.
  
  
  RESULTS
  Levels of 5-HTpls and 5-HTplt were significantly higher in patients with CaHD (median 5-HTpls 325 nmol/l and 5-HTplt 18.9 nmol/10(9) platelets) and CS (median 5-HTpls 155 nmol/l and 5-HTplt 16.4 nmol/10(9) platelets) when compared to healthy controls (median 5-HTpls 9 nmol/l and 5-HTplt 3.7 nmol/10(9) platelets; p < 0.0001 and p = 0.003, respectively). There was a significant increase in 5-HTplt and 5-HTpls between the femoral vein and right heart (p = 0.007 and p = 0.0002, respectively). There was no significant difference in 5-HTplt or 5-HTpls between the right and left side of the heart, irrespective of the presence of a patent foramen ovale or of left-sided CaHD.
  
  
  CONCLUSIONS
  Plasma and platelet 5-HT levels are elevated in patients with CaHD. Despite exposure to similar levels of intracardiac plasma and platelet 5-HT, the development of valve dysfunction is heterogeneous. This suggests that individual heart valves have a susceptibility to the development of valvular dysfunction which is not related solely to plasma or platelet 5-HT levels.
authors.affiliation: Department of Cardiology, Royal Free Hospital, London, UK.
authors.forename: Sanjeev
authors.initials: S
authors.lastname: Bhattacharyya
authors.forename: Anita
authors.initials: A
authors.lastname: Jagroop
authors.forename: Dorothy M
authors.initials: DM
authors.lastname: Gujral
authors.forename: Carl
authors.initials: C
authors.lastname: Hayward
authors.forename: Christos
authors.initials: C
authors.lastname: Toumpanakis
authors.forename: Martyn
authors.initials: M
authors.lastname: Caplin
authors.forename: Dimitri P
authors.initials: DP
authors.lastname: Mikhailidis
authors.forename: Joseph
authors.initials: J
authors.lastname: Davar
mesh_terms: D000368:Aged; D001792:Blood Platelets / Q000378:metabolism*; D001800:Blood Specimen Collection / Q000379:methods; D002275:Carcinoid Heart Disease / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology; D006328:Cardiac Catheterization / Q000379:methods; D004452:Echocardiography / Q000379:methods; D005260:Female; D006349:Heart Valve Diseases / Q000097:blood / Q000175:diagnosis / Q000503:physiopathology; D006351:Heart Valves / Q000000981:diagnostic imaging* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012701:Serotonin / Q000097:blood / Q000378:metabolism; D013223:Statistics as Topic
chemical_list: D012701:Serotonin