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Current diagnosis of pulmonary arterial hypertension (PAH) is by measuring the pulmonary pressure non-invasively with echo Doppler and confirming it with invasive measurement of the pulmonary artery pressure. However, once the PAH is confirmed, the prognosis is poor. In the study of PAH, which test can measure the pulmonary artery pressure without a catheter inside the pulmonary artery.
Patients with connective tissue disease (systemic lupus erythematosus, sleroderma, Raynaud's phenomenonetc) (WHO class 1) or severe chronic obstructive pulmonary disease (COPD) (WHO Class 3) or dilated cardiomyopathy (WHO class 2) were enrolled in the study. These patients were arranged to the new Expansibility of the Femoral Vein test (EFV) first then followed by the right heart catheterization. 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) which 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. As this test was done in conjunction with a right heart catheterization, then the femoral vein pressure at baseline and during cough is recorded.
20 patients were enrolled from January 2015 to April 2016. All came with high suspicion of pulmonary HTN. The results showed that 15/20 patients had abnormal EFV test and ten (50%) had confirmed PAH. Five patients had abnormal EFV test and normal pulmonary HTN (25%). Five patients had normal EFV test and normal pulmonary pressures (25%). All the patients had normal femoral vein pressure at baseline and however, during cough all 90% of patients, the pressure of the femoral vein matched the pressure of the PA systolic pressure. These results showed for the first time, the PA pressure could be measured invasively without having a catheter present in the pulmonary artery pressure itself. Complete data on pulmonary artery pressure at rest during cough will be presented.
The patients with high risk for pulmonary hypertension can be measured minimally invasively with a catheter in the femoral vein. At baseline, the pressure in the femoral vein was very low. Upon strong cough, the femoral pressure raised and matched the pulmonary artery pressure. Larger scale of clinical trial or registries of this new technique to confirm its reproducibility and validity and are needed.