Refining Perforator Selection for DIEP Breast Reconstruction Using Transit Time Flow Volume Measurements

Transit time flow volume has been used in cardiac surgery to assess small vessel flow characteristics. This study examines the usefulness of transit time flow volume (TTFV) in assessing perforator vessels in deep inferior epigastric artery perforator (DIEP) flap harvesting. The purpose of this study was to evaluate the correlation among computed tomographic angiography (CTA), intraoperative TTFV measurements, and hand-held Doppler signals in identifying perforators. Ten consecutive free DIEP breast reconstructions were prospectively evaluated using CTA to identify abdominal wall perforators. Intraoperatively, perforating vessels >1 mm in diameter were evaluated with a conventional hand-held 8-MHz Doppler and a TTFV measurement device. Vessel location was correlated with preoperative CTA . Waveform patterns and TTFV measurements were recorded for each vessel and correlated with both CTA and hand-held Doppler signals. Of the 54 perforators identified, TTFV showed arterial flow waveforms in 15 of 16 perforators identified by CTA and in 2 of the remaining 38 vessels. The sensitivity and specificity of TTFV in identifying arterial perforators were 94 and 95%, respectively. In contradistinction, hand-held Doppler was misleading in 70% of vessels. TTFV distinguishes arterial from venous waveforms in vessels that appear arterial by hand-held Doppler signals. CTA and TTFV are highly correlated, and the use of TTFV may prevent poor perfusion seen in some DIEP flaps.