title: Near-infrared imaging for the assessment of anastomotic patency, thrombosis, and reperfusion in microsurgery: a pilot study in a porcine model.
abstract: BACKGROUND
  Advances in microsurgical techniques have increased the use of free tissue transfer. Methods of intraoperative flap perfusion assessment, however, still rely primarily on subjective evaluation of traditional clinical parameters. Anastomotic thrombosis, if not expeditiously identified and revised, can result in flap loss with significant associated morbidity. This study aims to evaluate the use of near-infrared (NIR) fluorescence imaging in the assessment of microsurgical anastomotic patency, thrombosis, and vascular revision.
  
  
  METHODS
  A model of pedicle thrombosis was created using bilateral abdominal flaps isolated on deep superior epigastric vascular pedicles in four Yorkshire pigs. Following flap elevation, microvascular arterial and venous anastomoses were performed unilaterally, preserving an intact contralateral control flap. Thrombosis was induced at the arterial anastomosis site using ferric chloride, and both flaps imaged using NIR fluorescence angiography. The thrombosed vascular segments were subsequently excised and new anastomoses performed to restore flow. Follow-up imaging of both flaps was then obtained to confirm patency using fluorescence imaging technology.
  
  
  RESULTS
  Pedicled abdominal flaps were created and successful anastomotic thrombosis was induced unilaterally in each pig. Fluorescence imaging technology identified large decreases in tissue perfusion of the thrombosed flap within 2 minutes. After successful revision anastomosis, NIR imaging demonstrated dramatic increase in flow to the reconstructed flap, but intensity did not return to pre-thrombosis levels.
  
  
  CONCLUSIONS
  Early identification of anastomotic thrombosis is important in successful free tissue transfer. Real-time, intraoperative evaluation of flap perfusion, anastomotic thrombosis, and successful revision can be performed using NIR fluorescence imaging.
authors.affiliation: Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Plastic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Christina R
authors.initials: CR
authors.lastname: Vargas
authors.affiliation: Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Plastic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: John T
authors.initials: JT
authors.lastname: Nguyen
authors.affiliation: Division of Cancer Diagnostics and Therapeutics, Hokkaido University Graduate School of Medicine, Sapporo, Japan.
authors.forename: Yoshitomo
authors.initials: Y
authors.lastname: Ashitate
authors.affiliation: Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Plastic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Jason
authors.initials: J
authors.lastname: Silvestre
authors.affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Hematology and Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Vivek
authors.initials: V
authors.lastname: Venugopal
authors.affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Hematology and Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Florin
authors.initials: F
authors.lastname: Neacsu
authors.affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Hematology and Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Frank
authors.initials: F
authors.lastname: Kettenring
authors.affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Hematology and Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Curadel, LLC, Worcester, MA.
authors.forename: John V
authors.initials: JV
authors.lastname: Frangioni
authors.affiliation: Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Hematology and Oncology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Gioux
authors.affiliation: Department of Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.|Division of Plastic Surgery, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
authors.forename: Bernard T
authors.initials: BT
authors.lastname: Lee
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D019074:Epigastric Arteries / Q000601:surgery; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D007430:Intraoperative Care / Q000379:methods; D007431:Intraoperative Complications / Q000175:diagnosis*; D008866:Microsurgery / Q000379:methods*; D010865:Pilot Projects; D012086:Reoperation; D015424:Reperfusion; D019265:Spectroscopy, Near-Infrared; D013524:Surgical Flaps / Q000098:blood supply* / Q000601:surgery; D013552:Swine; D013927:Thrombosis / Q000175:diagnosis* / Q000209:etiology; D014654:Vascular Patency; D014680:Veins / Q000601:surgery