Novel Assessment of Intra-Operative Venous Outflow with Laser Assisted Indocyanine Green Angiography in Bilateral DIEP Breast Reconstruction

Background: Venous outflow remains a leading cause of flap failure in DIEP breast reconstruction, but although venous compromise is multifactorial, the physiology of venous outflow is still poorly understood. The incidence of venous congestion has ranged from 3-27%. Near-infra red Laser-assisted Fluorescence angiography has gained popularity as an adjunct in breast reconstruction intra-operatively for assessment of flap arterial perfusion following flap harvest. We present our preliminary experience to highlight the use of this technology for intra-operative assessment of venous outflow in hemi-DIEP flaps.

Methods: Ten hemi-DIEP flaps were prospectively assessed intra-operatively following flap harvest, prior to the start of ischemia time. All flaps were raised on a single dominant perforator only. Imaging capture following peripheral injection of indocyanine green was recorded to assess both the arterial and venous phases of flap perfusion. Data was independently reviewed to comprehensively assess venous outflow patterns and rates of egress flap in the entire flap using updated software tools. Procedural notes and postoperative complications were collected through a chart review.

Results:10 hemi-DIEP flaps were assessed using a standardized intra-operative protocol following dissection of the perforator, and prior to transfer. Three flaps demonstrated venous washout concentrated solely around the dominant perforator of the deep system only, with adequate outflow in less than 30% of the entire flap. This was clinically recognized following flap transfer and venous augmentation with a superficial vein was carried out emergently. The remaining flaps showed a broad gradient of perfusion throughout the flap, which may indicate greater network of linking vessels, similar to arterial perfusion. Venous maps expressed greater correlation with arterial timing perfusion maps rather than intensity perfusion, which are currently used for intra-operative arterial assessment.

Conclusion: Limited data exists on assessing venous outflow following anastomosis, yet nothing to our knowledge on venous assessment of flaps prior to transfer. This study is an on-going prospective investigation. Information can be ascertained intra-operatively prior to ischemia time to provide a comprehensive evaluation real-time of venous perfusion in the flap and subtlety in changes within flap regions that may provide early indications for venous augmentation. Further research is required to gain a better understanding of venous physiology and correlation with complications including unrecognized intra-operative venous congestion or fat necrosis.