CTEPH phenotype associated with existence, type of DVT
MedWire News: The clinical phenotype of chronic thromboembolic pulmonary hypertension (CTEPH) is associated with the existence and type of deep vein thrombosis (DVT), suggest study findings.
In acute pulmonary embolism (PE), DVT, especially proximal DVT, is thought to be associated with the larger and proximal obstruction of pulmonary arteries.
However, it remains uncertain whether the existence and type of residual DVT are associated with the clinical phenotype of CTEPH, especially the central extent of thrombi in the pulmonary arteries," say Nobuhiro Tanabe (Chiba University, Japan) and colleagues.
The researchers analyzed the association between DVT and DVT type, and pulmonary hemodynamics, CT obstruction index, and other clinical parameters, in 91 consecutive patients aged an average of 56 years, who underwent 16- or 64-slice multidetector CT angiography and indirect venography.
In total, 45 patients (49.5%) had a history of DVT, of whom 33 were classified as central type and 12 as distal (calf) type. Thirty patients (33.0%) showed abnormalities in screening for coagulopathy and 24 (26.4%) had antiphospholipid antibodies.
Compared with DVT-negative patients, there was a significantly greater proportion of DVT-positive males (female:male = 25:20 vs 35:11) and DVT-positive patients had a more frequent history of acute embolic episodes (68.9 vs 34.8%). Furthermore, the DVT-positive group had significantly fewer HLA-B*5201-positive cases (22.7 vs 42.9%) but more D-dimer positive cases (39.5 vs 13.6%).
No significant differences in the CT obstruction index and pulmonary hemodynamics were seen between the two groups.
Further analysis showed that in the HLA-B*5201-negative group, a greater proportion of DVT-positive patients were male (44.1 vs 16.7%) and had more frequent acute embolic episodes (70.6 vs 29.4%), compared with DVT-negative patients.
In contrast, no significant difference in clinical parameters was seen between DVT-positive and negative patients in the HLA-B*5201-positive group.
Compared with patients with distal DVT, those with proximal DVT were predominantly male (female:male = 15:8 vs 10:2), had a significantly longer duration of symptoms from onset (42.5 vs 16.5 months), a larger CT obstruction index (48.6 vs 34.1%), and a higher mean pulmonary arterial pressure (48.2 vs 40.8 mm Hg).
In addition, proximal DVT in HLA-B*5201-negative patients was associated with a larger CT obstruction index as well as a higher central disease score than in distal DVT patients.
"To our knowledge, this is the first study showing that existence and type of DVT are associated with the clinical phenotype of CTEPH. Proximal DVT appears to contribute to the central type of CTEPH only in HLA-B*5201-negative patients," conclude the authors in International Journal of Cardiology.
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By Ingrid Grasmo