Annulus paradoxus and annulus reversus on tissue Doppler in constrictive pericarditis
The term “annulus paradoxus” was proposed by Ha JW et al to indicate the inverse correlation of E/E’ to pulmonary capillary wedge pressure (PCWP) on tissue Doppler evaluation in constrictive pericarditis. Usually a positive correlation is found in patients with primary myocardial disease between E/E’ and PCWP . In their study of 10 patients, E’ was not elevated despite high left ventricular filling pressures. Hence E/E’ was low, with a mean 9 and it was <15 in 9 of their 10 patients.
Another study of 130 surgically confirmed patients with constrictive pericarditis from Mayo clinic reported similar findings . They noted significantly lower E/E’ ratios at medial mitral annulus in patients with constrictive pericarditis compared with patients without constrictive pericarditis (mean 5.8 vs 16.1). The authors acknowledged the preserved or accentuated E’ velocity in constrictive pericarditis leading to the lower than expected E/E’ in the setting of increased left ventricular filling pressure as annulus paradoxus.
But Alraies MC et al challenged the concept of annulus paradoxus in constrictive pericarditis while reporting their study of 49 surgically confirmed constrictive pericarditis . Their patients underwent right heart study with measurement of PCWP after an echocardiographic evaluation. They could not find any correlation between septal, lateral or mean E/E’ and PCWP in constrictive pericarditis. In fact they suggested revisiting the phenomenon of “annulus paradoxus” in constrictive pericarditis.
Chhabra L et al in a comment to this article pointed out that though the larger study from Mayo Clinic strongly favour the presence of annulus paradoxus, direct correlation of E/E’ ratio with left sided filling pressures was not performed . They called for a restudy of this relation in future large sized controlled prospective investigation.
Reuss CS et al reported on tissue Doppler study of mitral annular velocities in 14 patients with constrictive pericarditis, 10 with restrictive cardiomyopathy and 17 normal subjects . They noted that in controls, mitral lateral annular E’ velocity was 25% higher than medial E’ velocity. In constrictive pericarditis, the averaged lateral E’ velocity was 2% lower than medial E’ velocity. They termed this reversal of lateral and medial E’ velocities compared to normal subjects as “annulus reversus”.
Patil DV et al in their study of 23 patients who underwent pericardiectomy for constrictive pericarditis also refers to this “annulus reversus” . They documented that the ratio of medial to lateral mitral annular velocities reduced from 1.08 to 0.87 (p<0.03) after pericardiectomy. But “annulus reversus” was found to persist in 6 ‘responders’, reflecting 50% reduction in its incidence after pericardiectomy (p<0.001).
The lower lateral mitral annular velocity in constrictive pericarditis is thought to be due to the tethering by thickened pericardium.