The Second Investigation of the Management of Pericarditis (IMPI-2) Trial will compare the effectiveness and safety of complete percutaneous pericardial drainage facilitated by intrapericardial alteplase (recombinant human tissue-type plasminogen activator) to conventional pericardiocentesis when indicated in 2176 patients with large pericardial effusion due to tuberculous and non-tuberculous pericarditis. An internal pilot study of 218 patients will initially confirm the feasibility of conducting a large-scale multi-centre clinical trial of intrapericardial fibrinolysis in patients with large pericardial effusion, and also provide preliminary safety data, following a dose finding study of intrapericardial alteplase.

Intrapericardial fibrinolytic agents are used in the drainage of tuberculous, purulent, neoplastic and other inflammatory pericardial effusions to prevent recurrent effusions and constrictive pericarditis. This use is based on evidence from case reports and a small trial that did not have the statistical power to reliably evaluate the effect of pericardial drainage facilitated by intrapericardial fibrinolysis on safety and important clinical outcomes.

The Second Investigation of the Management of Pericarditis (IMPI-2) Trial will compare the effectiveness and safety of complete percutaneous pericardial drainage facilitated by intrapericardial alteplase (recombinant human tissue-type plasminogen activator) to conventional pericardiocentesis when indicated in 2176 patients with large pericardial effusion due to tuberculous and non-tuberculous pericarditis. An internal pilot study of 218 patients will initially confirm the feasibility of conducting a large-scale multi-centre clinical trial of intrapericardial fibrinolysis in patients with large pericardial effusion, and also provide preliminary safety data, following a dose finding study of intrapericardial alteplase.

Hypothesis: We hypothesise that patients with large pericardial effusion randomized to intrapericardial alteplase to ensure complete pericardial drainage will have at least a 35% reduction in cardiac tamponade requiring pericardiocentesis or constrictive pericarditis compared to conventional pericardiocentesis when indicated.

Objectives: The primary objectives of the IMPI-2 Trial are:

1. To demonstrate the feasibility of conducting a multicentre clinical trial of intrapericardial fibrinolysis in patients with large pericardial effusion, and to assess the safety of intrapericardial alteplase in an internal pilot study, and
2. To determine the effectiveness of intrapericardial alteplase in reducing the composite outcome of cardiac tamponade requiring pericardiocentesis or constrictive pericarditis in patients with large pericardial effusion in the full trial.

Should the internal pilot study demonstrate feasibility and safety; all 218 patients will be rolled-over into the full scale IMPI-2 trial of 2176 participants. The primary outcome is the first occurrence of cardiac tamponade requiring pericardiocentesis or constrictive pericarditis. The secondary safety endpoint is safety of intrapericardial fibrinolysis measured by effect on major bleeding, and serious and non-serious adverse events. The secondary efficacy outcomes are constrictive pericarditis, and cardiac tamponade requiring pericardiocentesis, analysed separately, and persistent or recurrent pericardial effusion without cardiac tamponade, hospitalisation, and death. The secondary diagnostic outcomes are proportion with bacteriologically confirmed tuberculosis from any organ or tissue; time to diagnosis of bacteriologically confirmed tuberculosis in days; accuracy of novel tests for the diagnosis of tuberculosis; proportion with specific diagnosis of any pericardial disease; time to diagnosis of a specific pericardial disease in days.

Study Design: IMPI-2 is a prospective randomized open blinded end-point trial that will enroll 2176 patients with large pericardial effusion over 36 months from up to 30 centres in South Africa and Africa. Eligible patients will be randomly assigned to receive complete pericardial drainage facilitated by intrapericardial fibrinolysis or conventional pericardiocentesis when indicated on enrollment to the study. Patients will be followed at 2 weeks, 6 weeks, 12 weeks, and in months 6, and 12 after enrollment. The IMPI Project Office, University of Cape Town, South Africa will manage and coordinate the study in association with the Pericarditis Research Unit, Walter Sisulu University, South Africa and the Population Health Research Institute, McMaster University, Canada.

Importance: IMPI-2 addresses very serious complications of large pericardial effusion (i.e., cardiac tamponade and constrictive pericarditis), which are associated with high mortality despite pericardiocentesis or pericardiectomy. This study will utilise the research network that was established by the IMPI trial which was completed in 2014.

Inclusion Criteria:

1. Age ≥ 18 years of age;
2. Confirmed large pericardial effusion on echocardiography (i.e., echo free space ≥1 cm anterior to the right ventricle of the heart in diastole);
3. Willingness to participate for the full duration of the trial (i.e., 12 months); and
4. Provision of written informed consent.

Exclusion Criteria:

1. Age < 18 years;
2. Uraemic pericarditis (i.e., urea > 21.4 mmol/l);
3. Thrombocytopenia (i.e., < 100,000 platelets per µl);
4. Presence of a contra-indication to the administration of a fibrinolytic agent (i.e., major haemorrhage or major trauma; coincidental stroke; major surgery in the previous 5 days; blood pressure >200/100 mmHg).

Individual patient data will be made available on request at the end of the study, subject to approval by the Steering Committee of the IMPI-2 Trial.