Intermittent compression units for severe post-phlebitic syndrome: a randomized crossover study. Prevention and treatment of postphlebitic syndrome: results of a 3-part study.
Although uncommon, severe post-phlebitic syndrome may be associated with persistent, intractable pain and swelling that interfere with work and leisure activities. This study was performed to determine whether intermittent compression therapy with an extremity pump benefits patients with this condition and, if so, whether the benefit is sustained.
                The study was a randomized crossover trial. Over the period 1990 to 1996, all patients in the clinical thromboembolism program of an Ontario teaching hospital who had a history of deep vein thrombosis and intractable symptoms of post-phlebitic syndrome were recruited into the study. The study involved using an extremity pump twice daily for a total of 2 months (20 minutes per session). The patients were randomly assigned to use either a therapeutic pressure (50 mm Hg) or a placebo pressure (15 mm Hg) for the first month. For the second month, the patients used the other pressure. A questionnaire assessing symptoms and functional status served as the primary outcome measure and was administered at the end of each 1-month period. A symptom score was derived by summing the scores for individual questions. At the end of the 2-month study, patients were asked to indicate their treatment preference and to rate the importance of the difference between the 12 pressures. Treatment was considered successful if the patient preferred the therapeutic pressure and stated that he or she would continue using the extremity pump and that the difference between the therapeutic and placebo pressures was of at least slight importance. All other combinations of responses were considered to represent treatment failure. Patients whose treatment was classified as successful were offered the opportunity to keep the pump and to alter pressure, frequency and duration of pump use to optimize symptom management. In July 1996 the authors contacted all study participants whose treatment had been classified as successful to determine whether they were still using the pump and, if so, whether they were still deriving benefit.
                In total 15 consecutive patients (12 women and 3 men) were enrolled in the study. The symptom scores were significantly better with the therapeutic pressure (mean 16.5) than with the placebo pressure (mean 14.4) (paired t-test, p = 0.007). The treatment for 12 of the patients (80%, 95% confidence interval 52% to 96%) was considered successful. Of these, 9 patients continued to use the pump beyond the crossover study and to derive benefit.
                The authors conclude that a trial of pump therapy is worthwhile for patients with severe post-phlebitic syndrome and that a sustained beneficial response can be expected in most such patients. The true incidence of postphlebitic syndrome (PPS) following proximal deep venous thrombosis (DVT) and the efficacy of graduated compression stockings in preventing and treating PPS are unknown.
                A 3-part study of 202 patients evaluated 1 year after proximal DVT: 2 randomized placebo-controlled trials of stockings and 1 prospective cohort of untreated patients. Patients were evaluated for PPS, using a standardized questionnaire, and for venous valvular incompetence, using photoplethysmography and venous Doppler. They were enrolled in study 1 or study 2 if they did not have symptomatic PPS and did not have or had venous valvular incompetence, respectively, and into study 3 if they had symptomatic PPS. Study 1 patients were left untreated and followed up for development of PPS every 6 months for a mean of 55 months. Study 2 patients were randomized to a below-knee stocking (20-30 mm Hg) or a matched placebo stocking, and followed up for development of PPS every 6 months for a mean of 57 months. Study 3 patients were randomized to an active stocking (30-40 mm Hg) or a matched placebo stocking and followed up every 3 months for treatment failure, defined a priori.
                In study 1, 6 (5.0%) of 120 patients were categorized as treatment failures, a rate similar to placebo-treated study 2 patients (P =.10). In study 2, 0 (0%) of 24 active and 1 (4.3%) of 23 placebo-treated patients were categorized as treatment failures (P =.49). In study 3, 11 (61.1%) of 18 active and 10 (58.8%) of 17 placebo-treated patients were categorized as treatment failures (P>.99).
                Most patients do not have PPS 1 year after proximal DVT, and do not require stockings. We failed to show a benefit of stockings in patients with PPS, but the small numbers preclude definitive conclusions.
There is some evidence of a beneficial effect of intermittent pneumatic compression units, but the study was too small and of too short a duration to draw strong conclusions. Further research is needed in order to assess whether intermittent pneumatic compression units give long term reduction and relief of the symptoms caused by post-thrombotic syndrome, and prevent deterioration and leg ulceration. The use of elastic compression stockings to treat post-thrombotic syndrome cannot be supported on the basis of the currently available data.