1. In contrast to the extensive documentation on diagnosis and treatment of deep venous thrombosis (DVT), information about long-term complications, clike the post-thrombotic syndrome (PTS), is scarce. Most studies report on clinical examination only, whereas adequate haemodynamic investigation is lacking. Therefore 81 patients with venographically confirmed lower extremity DVT were clinically and haemodynamically reexamined 7–13 years after DVT (mean 10 years) to assess PTS. Interest was focused on the relation between clinical and haemodynamic PTS and the relation between location of the initial DVT and incidence of PTS.
2. Clinical signs and symptoms of PTS were classified according to the latest consensus of the international consensus committee on chronic venous disease. Non-invasive venous vascular laboratory tests were performed to assess the venous outflow resistance and calf muscle pump function (CMP). CMP was determined by the supine venous pump function test (SVPT).
3. Clinically only 20 of 81 patients (25%) were asymptomatic, 34 (42%) had mild PTS (class 1–3), 25 (31%) moderate PTS (class 4) and 2 (2%) severe PTS (class 5–6); 57% had an abnormal CMP. Both the severity of clinical symptoms and the haemodynamic abnormalities were related to the location of the initial thrombus. Of the patients with distal DVT 11% developed moderate clinical PTS and 39% developed an abnormal CMP. CMP and difference in CMP between post-thrombotic and non-thrombotic leg were significantly related to the different classes of PTS.
4. This study indicates that 7–13 years after DVT 31% of the patients had moderate and 2% had severe clinical PTS, while 57% of the patients had abnormal haemodynamic findings (both related to the initial site of the thrombosis). Secondly, it reveals that the risk of PTS after distal DVT is not negligible, which causes concern about not diagnosing and treating patients with distal DVT. Thirdly, we have demonstrated that a functional test, such as the SVPT, is a sensitive test to assess post-thrombotic damage. Therefore its use as a screening tool after a period of DVT should be investigated to select patients at risk of PTS.