In order to assess patients for operative intervention of venous disease, accurate classification of venous disease must be performed. For SVC obstruction, patients should be classified according to the four groups described by Stanford and Doty in 1986 (Fig. 75-1). For the lower extremities, reporting standards in venous disease have been established by the International Consensus Committee on Chronic Venous Disease. Before being considered for intervention, each patient should be classified using the CEAP (Clinical, Etiologic, Anatomic, Pathophysiologic) system and the clinical severity scale based on pain, edema, venous claudication, skin changes, and ulceration. If present, ulcer size, duration, multiplicity, and incidence of recurrence after medical treatment should be documented. A thorough exam of the arterial system should be done, as venous and arterial diseases are not exclusive and arterial disease may contribute to poor healing of venous ulcers. Chronic nonhealing ulcers with unusual characteristics should be biopsied for evidence of malignancy.

A critical component of venous surgery is the use of noninvasive, functional studies to guide the surgeon in selecting the appropriate intervention. Severe chronic venous insufficiency may be due to primary valvular incompetence in superficial, deep, or perforator veins or secondary to deep venous thrombosis (DVT). Physiologic tests that have been described to assess the etiology of venous hypertension include foot volumetry, photoplethysmography, ambulatory venous pressure measurements, air plethysmography, and strain-gauge plethysmography. In our practice, we use strain-gauge plethysmography to identify abnormalities in calf muscle pump function, venous incompetence, and outflow obstruction. In addition, duplex ultrasonography is done to map venous anatomy and evaluate patency and competency in the deep, superficial, and perforating veins. It is imperative that venous reflux, valvular incompetency, and obstruction all
be considered prior to intervention for venous hypertension.

As noted above, venography is the gold standard of venous imaging when evaluating a patient with obstruction with the intent to intervene. Often percutaneous intervention can be accomplished during the same procedure. However, when planning more complex interventions, CTV and MRV are rapidly becoming detailed enough to use in surgical planning (Fig. 75-2). One clear advantage of a contrast study is the ability to assess venous incompetence with a descending venogram and the ability to measure venous pressure gradients, as well as better imaging of collateral veins. At present, a patient with a straightforward history of chronic obstruction is most efficiently imaged with ultrasound followed by venography with potential concomitant intervention, whereas a patient with a complicated history would be imaged first with CTV or MRV.