title: Evaluation of platelet count after isolated biological aortic valve replacement with Freedom Solo bioprosthesis.
abstract: OBJECTIVE
  The risk of thrombocytopenia in patients undergoing aortic valve replacement (AVR) with the Freedom Solo (FS) bioprosthesis is controversial. The aim of our study was to evaluate the postoperative evolution of platelet count and function after AVR in patients undergoing isolated biological AVR with FS.
  
  
  METHODS
  Between May 2005 and June 2010, 322 patients underwent isolated biological AVR. Of these, 116 patients received FS and were compared with 206 patients who received biological valves. Platelet count, mean platelet volume (MPV), and platelet distribution width (PDW) were evaluated at baseline (T0), first (T1), second (T2), and fifth (T3) postoperative days, respectively.
  
  
  RESULTS
  Overall in-hospital mortality was 1.5% with no difference between the two groups. Thirty-seven (11.5%) patients developed thrombocytopenia. FS implantation was associated with a higher incidence of thrombocytopenia compared with the control group (24.1% vs 4.4%, p<0.0001). Patients in the FS group showed a lower platelet count than the control group at T1 (99.4±38×10(3) μl(-1) vs 122.5±41.6×10(3) μl(-1), p<0.001), T2 (79.7±36.3×10(3) μl(-1) vs 122.5±43.3×10(3) μl(-1), p<0.001) and T3 (86.6±57.4×10(3) μl(-1) vs 158.4±55.8×10(3) μl(-1), p<0.001). Moreover, the FS group also had a higher MPV (11.6±0.9 fl vs 11±1 fl, p<0.001) and higher PDW (15.1±2.3 fl vs 13.9±2.1 fl, p<0.001) at T3. In a multivariable analysis, FS (p<0.0001), body surface area (p<0.0001), cardiopulmonary bypass time (p=0.003), and lower preoperative platelet counts (p=0.006) were independent predictors of thrombocytopenia.
  
  
  CONCLUSIONS
  The FS valve might increase the risk of thrombocytopenia and platelet activation, in the absence of adverse clinical events. Prospective randomized studies on platelet function need to confirm our data.
authors.affiliation: Department of Cardiothoracic Surgery, Fondazione G. Monasterio CNR-Regione Toscana, Via Aurelia Sud, 54100 Massa, Italy. antoniomiceli79@alice.it
authors.forename: Antonio
authors.initials: A
authors.lastname: Miceli
authors.forename: Daniyar
authors.initials: D
authors.lastname: Gilmanov
authors.forename: Michele
authors.initials: M
authors.lastname: Murzi
authors.forename: Maria S
authors.initials: MS
authors.lastname: Parri
authors.forename: Alfredo G
authors.initials: AG
authors.lastname: Cerillo
authors.forename: Stefano
authors.initials: S
authors.lastname: Bevilacqua
authors.forename: Pier A
authors.initials: PA
authors.lastname: Farneti
authors.forename: Mattia
authors.initials: M
authors.lastname: Glauber
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001705:Bioprosthesis / Q000009:adverse effects*; D001792:Blood Platelets / Q000473:pathology; D048429:Cell Size; D005260:Female; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010976:Platelet Count; D011474:Prosthesis Design; D012189:Retrospective Studies; D013921:Thrombocytopenia / Q000209:etiology*