The occurrence of effusive constrictive pericarditis (ECP) of tuberculosis origin in a cohort of patients with large effusions

Abstract

Introduction : Effusive constrictive pericarditis (ECP) is a clinical syndrome characterized by concurrent pericardial effusion and pericardial constriction where constrictive haemodynamics are persistent after the pericardial effusion is removed. Although first observed in the 1960s, it was not until the publication of a 13 patient-case series by Hancock in 1971, and the prospective cohort publication by Sagrista-Sauleda in 2004, that more information about the aetiology, incidence, and prognosis of effusive-constrictive pericarditis became known (Sagrista-Sauleda, Angel, Sanchez, Permanyer-Miralda, and Soler-Soler 2004). Hancock (1971) first recognized that some patients presenting with cardiac tamponade did not have resolution of their elevated right atrial pressure after removal of the pericardial fluid. In these patients, pericardiocentesis converted the haemodynamics from those typical of tamponade to those of constriction. Thus, the restriction of cardiac filling was not only due to the pericardial effusion but also resulted from pericardial constriction (predominantly the visceral pericardium). The hallmark of effusive-constrictive pericarditis is the persistence of elevated right atrial pressures after the intrapericardial pressure has been reduced to normal levels by the removal of the pericardial fluid. Aims and Objectives : This study was carried out to determine the prevalence of ECP in a cohort of patients with large effusions of Tuberculosis origin. The primary objective was to measure pre and post- pericardiocentesis intrapericardial and right atrial cardiac pressures in all patients undergoing pericardiocentesis in order to determine the relative proportion of effusive constrictive pericarditis in these patients. The secondary objective was to determine if any echocardiographic features can help predict the presence of ECP by studying the three parameters two-week post-pericardiocentesis. Methodology : Fifty consecutive patients with pericarditis presenting to Groote Schuur Hospital and surrounding hospitals referred for pericardiocentesis, who met the inclusion criteria were recruited to participate in the study. All patients had the right atrial and intrapericardial pressures simultaneously measured and recorded, before and after pericardiocentesis. The pressures were analyzed to determine the presence of ECP, which was defined as failure of the right atrial pressure to fall by 50% or to a new level of ≤12 mmHg after the intrapericardial pressure is lowered to below 2 mmHg. Participants also had an echocardiogram done two weeks post pericardiocentesis. Three echocardiographic features of constriction were studied, to determine if they can predict the presence of ECP. The parameters studied were 1) Thickened pericardium, 2) Dilated inferior vena cava (IVC) and 3) Septal bounce. Results : This study showed a 34% (17 0f 50) prevalence of ECP in patients with TB pericarditis. It also showed a statistically difference in the right atrial and intrapericardial pressures pre and post pericardiocentesis, between patients with ECP and those without. The echocardiographic parameters studied showed no difference between ECP and non ECP, and also did not predict the presence of ECP. Discussion : In the cohort of patients (n=50), the prevalence of ECP was found to be 34%. This is much higher than that observed in the Sagrista-Sauleda et al., (2004) study. They found a prevalence of 1.3% amongst patients with pericardial disease of any type and 6.95% amongst patients with clinical tamponade. The authors did state that they expected the true prevalence to be higher than estimated as not all patients underwent catheterization. Pre-pericardiocentesis pressures, both right atrial and intrapericardial, were found to be higher in patients with ECP than in those without. This is in keeping with published results, such as the study of Hancock (1971) The echocardiographic parameters studied were two weeks post pericardiocentesis, because the diagnostic accuracy of echocardiogram has been shown to be very poor at the time of tamponade. The presence of these parameters (thickened pericardium, dilated IVC and septal bounce), did not predict the presence of ECP. This could be due to the fact that less than 50% of participants had an echocardiogram two weeks post pericardiocentesis. Conclusions : The results of this study show that ECP is actually more common than thought in a population with TB pericarditis. This syndrome may be missed in most patients due to the fact that not all centres measure right atrial and intrapericardial pressures at the time of pericardiocentesis. Echocardiography is not able to predict the presence of ECP. Other non-invasive imaging techniques such is computerized tomography (CT) and cardiac magnetic resonance imaging (CMRI) have shown good results in diagnoses of ECP. The importance of early diagnosis of ECP lies in recognition that removal of pericardial fluid alone may not be enough; patients may need to have surgery. Given the high prevalence shown by the study, ideally all patients with pericardial effusion should have haemodynamic monitoring at the time of pericardiocentesis.