title: Heparin coating on ureteral Double J stents prevents encrustations: an in vivo case study.
abstract: OBJECTIVE
  To evaluate the ability of heparin coating to inhibit Double J stent encrustation and compare it with the classic polyurethane Double J stent.
  
  
  METHODS
  The study involved five patients with bilateral obstructions, who required bilateral ureteral Double J stent placement. Every patient received a heparin-coated Double J stent and a traditional polyurethane Double J stent for 1 month. After removal, the stents were analyzed using field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), and micro-infrared spectrophotometry (Micro-IR). These same techniques were used to analyze the heparin-coated and uncoated stents before insertion. The thickness, extension, and composition of encrustation of the coated and uncoated stents were compared. Moreover, two heparin-coated stents were analyzed with the same techniques after they had been in place for 10 and 12 months.
  
  
  RESULTS
  FESEM analysis showed that the difference in encrustation thickness and extension between the two groups was significant. EDS and Micro-IR confirmed that in the heparinized stents the encrustations were not as uniform and compact as those in the uncoated stents. The stents that were left in place long-term were free of encrustations and had no changes in the heparin layer.
  
  
  CONCLUSIONS
  Heparin coating reduces stent encrustation. Moreover, as no changes were seen in the heparin layer, we concluded that covalent heparin bonding enhances its adhesion to the polyurethane surface and ensures its stability for long periods. The heparin-coated stent appears to be a useful tool for long-term urinary drainage.
authors.affiliation: Dipartimento di Nefrourologia, S.S.C.V.D. per il trattamento integrato della calcolosi urinaria, Ospedale Maggiore S. Giovanni Battista, Torino, Italy. furix@libero.it
authors.forename: Furio
authors.initials: F
authors.lastname: Cauda
authors.forename: Valentina
authors.initials: V
authors.lastname: Cauda
authors.forename: Cristian
authors.initials: C
authors.lastname: Fiori
authors.forename: Barbara
authors.initials: B
authors.lastname: Onida
authors.forename: Edoardo
authors.initials: E
authors.lastname: Garrone
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects*; D003460:Crystallization; D020878:Device Removal; D005260:Female; D006493:Heparin / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011140:Polyurethanes; D015607:Stents / Q000009:adverse effects* / Q000382:microbiology; D013997:Time Factors; D014517:Ureteral Obstruction / Q000601:surgery
chemical_list: D000925:Anticoagulants; D011140:Polyurethanes; D006493:Heparin