title: Thrombocytopenia following implantation of the stentless biological sorin freedom SOLO valve.
abstract: OBJECTIVE
  Stentless biological valves have proven advantages in hemodynamic performance and left ventricular function compared to stented biological valves. Following a marked postoperative fall in the platelet count of patients after implantation of the Freedom SOLO valve, the study aim was to confirm clinical observations that this effect was more severe in patients receiving Freedom SOLO valves than in those receiving St. Jude Medical (SJM) mechanical aortic valves.
  
  
  METHODS
  Preoperative and postoperative platelet counts were compared in two groups of patients who underwent aortic valve replacement (AVR) without any concomitant procedures between January and December 2007. Patients received either a Freedom SOLO valve (n = 28) or a SJM mechanical valve (n = 41). Mean values of platelet counts were compared using three multiple linear regression models.
  
  
  RESULTS
  Platelet counts were significantly lower in the Freedom SOLO group than in the SJM group from the first postoperative day (POD 1) up to POD 6 (p <0.001). In three patients of the Freedom SOLO group the platelet count fell below 30x10(9)/l, while the lowest level in the SJM group was 75x10(9)/l. Based on multiple linear regression models, the type of valve implanted had a statistically significant influence on postoperative platelet counts on POD 1, POD 3, and POD 5 (p <0.001).
  
  
  CONCLUSIONS
  Whilst the reason for this phenomenon is unknown, the use of consistent monitoring should prevent severe falls in platelet count from becoming dangerous for the patient. Further studies are required to investigate the phenomenon since, despite a shorter cardiopulmonary bypass time, the fall in platelet count was more profound in the Freedom SOLO group.
authors.affiliation: Department of Cardiovascular Surgery, University Medical Center, Ljubljana, Slovenia.
authors.forename: Borut
authors.initials: B
authors.lastname: Gersak
authors.forename: Urska
authors.initials: U
authors.lastname: Gartner
authors.forename: Miha
authors.initials: M
authors.lastname: Antonic
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000601:surgery; D001705:Bioprosthesis / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006349:Heart Valve Diseases / Q000601:surgery*; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D010976:Platelet Count; D011183:Postoperative Complications; D011379:Prognosis; D011474:Prosthesis Design; D012189:Retrospective Studies; D013921:Thrombocytopenia / Q000097:blood / Q000209:etiology*; D016896:Treatment Outcome