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Current diagnosis of pulmonary HTN is by measuring the pulmonary pressure non-invasively with echo Doppler or invasively by direct measurement of the pulmonary artery pressure. However, with Doppler echocardiography, the positive predictive value is not very high because of many false positives. We suggest a new test which can give better predictive value.
Patients with suspected of pulmonary HTN by echocardiography and Doppler studies were enrolled. First, the patients underwent the new Expansibility of the Femoral Vein test (EFV). Then the patient underwent the right heart catheterization (RHC) which confirmed the results of the EFV. During the RHC, the baseline femoral vein pressure and during cough were measured. The study group underwent the new Expansibility of the Femoral Vein (EFV) and had treatment based on its results. The EFV is the ultrasound study of the femoral vein examining its size and expansibility during strong cough. In general, the location of the femoral artery and vein to be checked is the sagittal plane immediately proximal to the bifurcation of the superficial and deep femoral artery. The size of the femoral vein is a little larger than the size of the femoral artery. If the size of the femoral vein during cough is 3 times larger than the one at baseline, the test is considered normal. If the size of the femoral vein is >3 times larger than then baseline, it is considered abnormal suggesting excessive venous pooling. If the femoral vein expands only <2 times of the baseline during cough, it is considered abnormal suggesting present or future pulmonary hypertension. If this test was done in conjunction with a right heart catheterization, then the femoral vein pressure at baseline and during cough is recorded.
25 patients were enrolled from January 2015 to April 2016. All came with history of high suspicion of pulmonary HTN by echo Doppler. They were the patients with connective tissue disease (WHO Classification group 1), dilated cardiomyopathy (group 2), severe chronic obstructive pulmonary disease (COPD) (group 3), or old pulmonary embolism (group 4), chronic kidney disease (group 5). The results showed that 20/25 patients had abnormal EFV test confirmed by RHC (positive predictive value of 80%). All five patients with normal EFV test showed normal pulmonary artery pressure (no pulmonary HTN). So the negative predictive value of the EFV test was 100%. The data of femoral vein pressure at baseline and during cough will be presented.
The patients with high risk of pulmonary HTN should have the EFV early and if the results are positive, the patient should undergo the RHC to confirm its presence. A negative EFV test suggests no pulmonary HTN. Larger scale of clinical trial or registries of this new technique are needed.