Abstract 3568: Tissue Doppler Imaging is Superior to Brain Natriuretic Peptide Levels in Differentiating Constrictive Pericarditis From Myocardial Disease
Background: Non-invasive diagnosis of constrictive pericarditis (CP) remains a clinical challenge. Brain natriuretic peptide (BNP) level has been suggested to differentiate CP from myocardial disease. However, CP from secondary causes such as previous surgery or radiation has been reported to be associated with higher levels of BNP. We hypothesized that tissue Doppler imaging (TDI) may be useful in differentiating CP from cardiac muscle disease when BNP levels show significant overlap.
Methods: The study group consisted of 20 patients, 10 with surgically confirmed CP (62±13 yrs, 10 males) and 10 with biopsy-proven systemic amyloidosis who had cardiac involvement (61±7 yrs, 7 males). The etiology of CP was previous surgery in 3, viral pericarditis in 3, radiation in 2, and idiopathic in 2 patients. Mean longitudinal mitral annular velocities were averaged from the lateral and septal corners during ejection, filling and isovolumic phases of cardiac cycle. Biphasic waves during isovolumic periods were quantified as a difference of peak positive (shortening) and peak negative (stretching) velocities. BNP measurements were performed within 48 hours of the echocardiographic examination in both the groups.
Results: Longitudinal isovolumic contraction (IVC) and early diastolic velocities (E’) were significantly higher in CP than in cardiac amyloidosis (3.6±1.8 v 1.7±1.0 cm/s, P=.009, and −7.1±0.8 v −3.8±1.2, P<.0001 respectively). A mean E’ velocity of 6 cm/s differentiated patients with CP from those with cardiac amyloidosis with no overlap. BNP levels were lower in CP but showed considerable overlap (256±126 vs 431±299, P=.05). Levels < 300 pg/ml were seen in 8(80%) patients with CP and in 3(30%) patients with amyloidosis. Biphasic velocities during IVC showed highest correlation with BNP levels (r = 0.87, P<.0001).
Conclusions: Diastolic dysfunction due to cardiac muscle or pericardial disease can result in similar values of BNP, however, the two conditions are readily differentiated on TDI. Preejection velocities are higher in patients with CP and provide further advantage in differentiating CP from cardiac muscle disease. Relative sparing of cardiac muscle shortening and stretch mechanics may explain lower values of BNP seen in CP.