Reply: The Utility of Preoperative Venous Testing for Lower Extremity Flap Planning in Patients with Lower Extremity Wounds.

Abstract

Sir: We would like to thank Dr. Cobb and Dr. Chan for their comments on our work.1 We respectfully disagree with their statement that there is insufficient evidence to suggest that venous disease negatively affects free tissue transfer outcomes. The majority of free tissue transfer failures occur because of venous thrombosis: delayed venous thrombosis is associated with flap loss and failed salvage,2 and many cases of venous congestion may be attributed to compromised intrinsic venous quality.3 Understanding a patient’s venous anatomy and pathologic condition is therefore crucial for maximizing flap success rates. No other studies investigate the role of preoperative venous imaging as a guide for surgical planning in patients undergoing free tissue transfer for lower extremity reconstruction. We analyzed outcomes after implementing a novel preoperative screening tool for venous abnormality: we want to emphasize that this was not a comparison study and it should not be interpreted in that fashion. Although randomized controlled trials are the gold standard for studying causal relationships, they are not conducted in free tissue transfer outcomes studies because of the low failure rates of this intervention. It is difficult to achieve microsurgical success and limb salvage in patients with underlying comorbidities such as peripheral vascular disease, diabetes mellitus, and calcified vessels. Arterial disease compromises vascular inflow into free flaps, placing a greater importance on efficient venous outflow for perfusion. Many of these patients also have lymphedema, chronic induration, and/or venous abnormality, so thorough venous evaluation is paramount. Although Dr. Cobb and Dr. Chan group venous reflux and thromboembolism under the single term “venous disease,” the distinction between the former two terms is important. If an occlusive thrombus is found in a deep vein, that vein is no longer considered for flap outflow, and this finding may be a contraindication to free tissue transfer surgery altogether. This stands in stark contrast to venous reflux and valvular dysfunction (which we would term “venous disease”), which are not outright contraindications to free tissue transfer. This distinction is important in our study, which demonstrated that preoperative venous studies can identify venous reflux and deep venous thrombosis, the latter of which requires active management before reconstructive surgery. With regard to our results, we believe that the higher flap success rates in the venous reflux and deep venous thrombosis groups actually strengthen our conclusion that preoperative venous studies are a helpful tool for executing successful free tissue transfer reconstruction. Because we used preoperative venous studies to guide vessel selection and surgical planning, we maintain that the 100 percent flap success rates in the venous reflux and deep venous thrombosis groups were at least in some part because of the information gleaned from venous studies in these patients. Lower extremity venous duplex imaging is noninvasive and inexpensive. In our institution, the ability to proactively manage conditions such as deep venous thrombosis and optimize vessel selection in the setting of venous disease has translated into excellent flap outcomes. In our experience, the benefits of venous studies outweigh the risks and they have therefore been integrated into the routine preoperative workup for every patient undergoing lower extremity free tissue transfer reconstruction. DISCLOSURE There are no financial disclosures, commercial associations, or any other conditions posing a conflict of interest to report for any of the authors. Paige K. Dekker, B.A.Kevin G. Kim, B.S.Karen K. Evans, M.D.Department of Plastic and Reconstructive SurgeryMedStar Georgetown University HospitalWashington, D.C.