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Dr Thomas S. Huber (Gainesville, Fla). Dr Modrall and his colleagues from the University of Texas Southwestern have documented the incidence of late venous morbidity after harvest of the superficial femoropopliteal vein and have thereby provided the final piece of data that we have all awaited. Somewhat surprisingly, they found that the deep vein harvest resulted in clinically significant venous morbidity only 15% of the time, while the sophisticated venous testing with air plethysmography was not particularly worrisome for the development of future events. Notably, concurrent harvest of the saphenous and deep veins was the only factor clearly associated with the development of late morbidity.

The study contributes to our overall understanding of the venous pathophysiology after deep vein harvest and documents the presence of significant venous obstruction, but no clinically significant changes in reflux, or calf muscle pump or residual venous volume, a surrogate for ambulatory venous pressure. Their findings both extend and corroborate their intermediate-term results and offer reassurance to those of us that find it necessary to harvest the superficial femoropopliteal more commonly than we care to admit. I have three requests and/or questions for the authors:

Despite the authors’ overwhelming experience with the use of the superficial femoropopliteal vein, I was somewhat concerned by their small sample size and retrospective study design. Please comment on any potential selection bias and the potential for a type II statistical error.

Please describe your preoperative evaluation and management strategies for a typical patient with an infected aortobifemoral bypass graft and severe peripheral vascular occlusive disease that requires a NAIS and possibly a concomitant infrainguinal bypass.

Please describe how we should counsel our patients in the perioperative period and detail any further adjuncts or techniques used to achieve these excellent results.

Overall, I strongly recommend the manuscript to the organization and the readership of the Journal. It is the type of study that we expect from the Southwestern group and one that contributes significantly to our clinical practices.

Dr J. Gregory Modrall: In regard to your first question, there is no question that this is a small sampling of our overall experience. When you look at the numbers we started with, we first of all honed in on only those patients who were at least 42 months after their deep vein harvest, which dropped the number tremendously.

Furthermore, the nature of our practice is such that we have a university hospital and two hospitals with large numbers of indigent patients. The indigent patients are often difficult to track down and reluctant to come back for unnecessary studies. Patients at our university hospital referral practice come from across the country, and it is difficult to compel them to come back for follow-up that is for research purposes alone.

The risk of a type II error probably is only pertinent to the results obtained for calf ejection fraction because the is P value for this comparison between harvested and control limbs approached significance. I will point out that approximately two-thirds of those patients had ejection fractions that were above the median and within normal limits, which is somewhat reassuring.

Regarding our preoperative evaluation and management strategies, we always obtain sonographic deep vein mapping before deep vein harvest. This study is used to identify any pathology of the deep vein, including any sclerotic or occluded veins, to obtain a baseline measurement of the vein, and to identify any variant anatomy, such as a bifurcated superficial femoral vein. We also look at the status of the ipsilateral saphenous vein in the event that an outflow procedure is necessary.

A common question that is raised is whether a concurrent outflow procedure is safe, knowing that this predisposes to acute and chronic venous morbidity. Our philosophy is to save the limb and worry about the minority of patients who develop these problems at a later time. We do, however, always counsel patients about the potential for acute venous morbidity, that being a fasciotomy, and a late chronic venous insufficiency.

In answer to your last question, the only adjunctive technique is the careful preservation of the profunda femoris vein and harvest the superficial femoral vein flush from its confluence with the profunda vein to avoid leaving a stump that may become a nidus for clot formation. In addition, we take only the length of vein that is required, because sparing the popliteal vein virtually assures the patient of avoiding both acute and long-term venous morbidity. We have never had a harvested limb develop acute or chronic venous morbidity if the popliteal vein was not harvested.