Objective: This study was conducted to determine whether Doppler recording of superior vena cava flow velocities can differentiate chronic obstructive pulmonary disease from constrictive pericarditis in patients with a respiratory variation of > or = 25% in mitral inflow E velocity.
Background: Although respiratory variation (> or = 25%) in mitral E velocity is the main diagnostic criterion for constrictive pericarditis by Doppler echocardiography, it can also be present in chronic obstructive pulmonary disease. Because the respiratory variation is due to increased change in intrathoracic pressure with respiration in chronic obstructive pulmonary disease, and to dissociation of intrathoracic-intracardiac pressure changes in constriction, it was hypothesized that the Doppler flow velocity pattern in the superior vena cava (affected by intrathoracic pressure) would be different in these two conditions.
Methods: Pulsed-wave Doppler recording of mitral and superior vena cava flow velocities in 20 patients with chronic obstructive pulmonary disease who had > or = 25% respiratory variation in mitral E-wave velocity were compared with those of 20 patients who had surgically proved constrictive pericarditis.
Results: Constrictive pericarditis and chronic obstructive pulmonary disease had similar respiratory variation in mitral E velocity (41% versus 46%). In the latter, the E/A ratio was lower (inspiration, 0.8+/-0.3 versus 1.5+/-0.7 [p < 0.0001]; expiration, 1.0+/-0.3 vs. 1.9+/-0.7 [p < 0.0001]) and deceleration time longer (inspiration, 198+/-53 ms versus 137+/-32 ms; expiration, 225+/-43 ms vs. 161+/-33 ms [p < 0.0001]). Inspiratory superior vena cava systolic forward flow velocity was significantly higher in chronic obstructive pulmonary disease (72.9+/-22.6 cm/s versus 36.2+/-9.3 cm/s, p < 0.0001), while expiratory systolic forward flow velocity was similar. Hence, there was a significantly greater respiratory variation in superior vena cava systolic forward flow velocity in chronic obstructive pulmonary disease without an overlap with constrictive pericarditis (39.5+/-18.8 cm/s vs. 4.2+/-3.4 cm/s, p < 0.0001).
Conclusions: Despite a similar respiratory variation in mitral E wave velocities, mitral inflow variables in chronic obstructive pulmonary disease are less restrictive compared with those in constrictive pericarditis. More importantly, patients with chronic obstructive pulmonary disease show a marked increase in inspiratory superior vena cava systolic forward flow velocity, which is not seen in patients with constrictive pericarditis.