Development of the postthrombotic syndrome: its management at different stages.

The postthrombotic syndrome consists of clinical features which follow thrombosis of deep venous return of the limb. Patterns of postthrombotic changes remain difficult to predict and once established, difficult to contain and reverse. Following a thrombotic event of the lower limb, 3 clinical stages can be observed which may be followed by intervening quiescent intervals. Stage I, or the early phase, is characterized by the residual obstructive process following acute venous occlusion. This can be manifested by either a bursting type of pain (venous claudication) or edema of the leg. A thrombotic process can involve the calf veins, thigh veins, pelvic veins, or any combination of the three. Specific clinical syndromes develop depending on the venous pump system involved. The venous pump system consists of the plantar calf pump and the thigh pump. These serve to propel blood upward. Involvement of any one or more of the 3 in the thrombotic processes can result in a relative obstruction with a specific pattern of clinical symptoms. Optimally, the venous thrombotic process should be treated during this early phase to prevent the subsequent events which may render the process irreversible. The second stage of the postthrombotic syndrome consists of the development of fat sclerosis. At this stage, the process becomes progressively irreversible as the extravasation of fibrin into the interstitial space results in progressive fibrosis and sclerosis. This results in damage to the skin and subcutaneous tissues which render the process irreversible. Specific treatment, while still introducible at this stage, can halt the progress of the syndrome, but rarely results in complete reversal.(ABSTRACT TRUNCATED AT 250 WORDS)