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Chen et al. Plast Aesthet Res 2023;10:24 https://dx.doi.org/10.20517/2347-9264.2022.136 Page 13 of 26

requiring evacuation. This should be paired with the assessment of anastomotic flow using Doppler
sonography. Secondary veins, such as the SIEV in the case of a DIEP flap, should be examined closely.
These veins should be opened to allow for assessment of their outflow. If the secondary veins are noted to
have robust outflow, they should be used for venous supercharging of the flap as described below (Venous
Flow Present).

Flaps or pedicles can be repositioned to achieve a more favorable lie without kinking. Autologous fat grafts
may be used to cushion the pedicle or maintain its position without twists or kinks. Re-evaluation of the
venous anastomosis or coupler is critical. A milking test can be used to ensure flow across the anastomosis
and throughout the length of the pedicle. If the flap vein was twisted or kinked relative to the recipient vein
during anastomosis, the anastomosis may need revision to avoid propagation. Venous vasospasm can cause
global congestion, which can usually be resolved by irrigating the vessels with vasodilators (papaverine,
lidocaine, verapamil, and nitroglycerin mixture) and warm salinex .
[109]

Venous flow diminished or absent
If there is absent or diminished flow in the anastomosis after mechanical factors and simple vasospasm have
been ruled out, the anastomosis should be taken down and inspected for thrombi. As venous supercharging
may be necessary, secondary veins should be examined closely as described below. The artery should also be
carefully inspected for signs of diminished flow. If the artery is noted to have abnormal flow, this vessel
should be treated using the algorithm above (See intraoperative management of arterial thrombosis). If
thrombus is noted in the proximal vein, direct thrombectomy with microforceps should be attempted. If the
thrombus is too extensive or distant for this approach, a 1-3 mm Fogarty catheter can be used to attempt
thrombus removal in the distal pedicle. Although there is concern that the use of Fogarty catheters on
microvasculature can increase the risk of endothelial denudation and thrombogenesis, studies on
complication rates following Fogarty catheterization so far have been conflicting and limited by small study
samples. While some studies have reported successful flap salvage using the Fogarty catheter, others have
found a higher rate of failure in flaps undergoing Fogarty catheter thrombectomy [101,110] . However, as there
have been no large-scale studies on the use of Fogarty catheters in flap salvage, and all previous studies are
subject to significant selection bias, we believe that Fogarty catheters have an important role in the
armamentarium of the reconstructive microsurgeon - especially when attempting to salvage flaps with more
extensive or proximal thrombi that are not accessible for direct thrombectomy. After the Fogarty catheter is
used, the vessels are typically flushed copiously with heparinized saline as per our arterial algorithm.

If no thrombus is visualized upon taking down the anastomosis, it is possible that there is evidence of intra-
flap venous insufficiency or thrombosis. Although ICG angiography is typically used to examine inflow to
the flap, venous outflow can be assessed using a washout phase. After the arterial flow is confirmed using
the ICG, a second examination can be done after a 2-3 min delay. If ICG dye remains in portions of the flap
after this delay, it is likely that these portions may be experiencing venous insufficiency. In cases of intra-
flap thrombosis, whether arterial or venous, chemical thrombolysis may be needed (see the arterial
treatment algorithm above). If only a portion of the flap is determined to suffer from venous insufficiency,
this non-viable tissue may simply be debrided.

Venous flow present
Evidence of persistent flap congestion in the setting of venous patency indicates the need for venous
supercharging, or additional venous flow augmentation. Of the two most common autologous breast
reconstructions, DIEP flaps are more likely than free TRAM flaps to be complicated by venous congestion
requiring flow augmentation, likely due to DIEP flaps having fewer perforators [107,111,112] .