Pericardial effusion/tamponade

Aetiology of effusion: (virtually any disease that involves the pericardium can cause an effusion)

• Idiopathic
  • Often seen as asymptomatic effusions in otherwise healthy people
• Infectious
  • Viral - echovirus, coxsackievirus, adenovirus, CMV, HBV, IMN, HIV/AIDS, SARS-CoV-2
  • Bacterial
  • HIV-associated
  • Fungal
  • Protozoal
• Inflammatory
  • Autoimmune - SLE, RA, scleroderma, dermatomyositis, Sjogren syndrome, IBD
  • Drug-induced autoimmune diseases - procainamide, hydralazine, isoniazid, cyclosporine
  • Arteritis - polyarteritis nodosa, temporal arteritis
  • Post-MI (Dressler syndrome)
  • Miscellaneous - sarcoidosis, Erdheim-Chester disease, Churg-Strauss disease, IgG4 disease
• Cancer (20%)
  • Malignant involvement - either by direct invasion or lymphatic seeding, having first involved mediastinal nodes. Tumour must involve epicardium to cause an effusion.
  • Primary - mesothelioma, fibrosarcoma, lipoma
  • Secondary - breast and lung carcinoma, lymphomas, Kaposi sarcoma
• Radiation-induced
• Early post-cardiac surgery
• Haemopericardium
  • Trauma
  • Post-MI free wall rupture
  • Endomyocardial biopsy
  • Dissecting aortic aneurysm
  • Device and procedure-related
  • Oral anticoagulants
• Congenital
• Miscellaneous
  • Chronic renal failure
  • Pulmonary HTN
  • Hypothyroidism
  • Protein malnutrition
  • Cholesterol
  • Amyloidosis
  • Polycystic kidney disease

Aetiology of tamponade

• Bacterial infection
• HIV-associated infections
• Bleeding from any cause
• Neoplastic disease
• Acute idiopathic pericarditis (low rate, but commonly seen due the high incidence)

Pathophysiology

• Pressure depends on the amount of fluid and the pericardial pressure-volume relation
  • Tamponade can occur acutely with as little as 150-200mL of fluid, but large slowly-accumulating effusions are often well-tolerated
• Main consequence of increased pressure is compression and collapse of right heart, which then leads to left heart underfilling
• Cardiac tamponade - a continuum from an effusion causing minimal effects to circulatory collapse. This can occur once the effusion reduces diastolic filling to the point that cardiac output declines.
  • Compensation occurs with increased adrenergic tone and parasympathetic withdrawal, leading to tachycardia, followed eventually by hypotension.
  • Patients who cannot mount an adrenergic response are more susceptible to tamponade
  • Cardiac filling pressure is particularly reduced during inspiration
  • Very unusual for tamponade to occur without circumferential effusion
• Effusions can be loculated or localised, resulting in regional tamponade,, especially after cardiac surgery

Presentation

• Effusions without tamponade
  • Do not cause symptoms in the absence of tamponade, although patients may have pain from pericarditis
  • Large effusions - muffled heart sounds, difficult to palpate cardiac impulse
  • Friction rub
• Tamponade
  • Beck's triad - hypotension, muffled heart sounds and elevated JVP - suggests severe tamponade
  • Tachycardia, followed by hypotension, then paradoxical bradycardia at end-stage
  • Paradoxical pulse - a drop >10mmHg in systolic BP during inspiration
    • The difference between the pressure at which Korotkoff sounds first appear, and that at which they are present with every contraction
    • Consider other causes - PE, CP, pulmonary disease with large variations in intra-thoracic pressure
  • Something called 'loss of the y descent of the RA or systemic venous pressures' is also characteristic
  • Often complain of dyspnoea, which is relieved sitting forward
  • Note tamponade can be confused with decompensated heart failure, PE, pulmonary HTN and RV MI - which all can cause hypotension, shock and elevated JVP.

Investigation

• ECG
• TTE
  • Grade as trivial (only seen in systole), small (echo free space in diastole <10mm), moderate (10-20mm), and very large (>25mm)
  • Can see frond-like or shaggy-appearing structures in pericardial space - clots, chronic inflammation, or neoplastic processes
  • Signs of tamponade:
    • Early diastolic collapse of RV
    • Late diastolic indentation or collapse of RA
    • Exaggerated respiratory variation in RV and LV size
• TOE
  • Not necessary for most situations
  • Have a role when the patient is stable and more information is needed
• CT
  • More accurate than TTE in estimating pericardial thickness
  • Attenuation similar to water suggests transudative effusion; while hyperdense effusions suggest malignancy, blood or purulence; and hypodense effusions suggest chylous effusion
  • Malignant effusions tend to have a thicker pericardium than benign ones
• MRI
  • Gadolinium MRI can directly assess for inflammation

Threatened tamponade if:

• Bacterial pericarditis - careful monitoring if <10mm, otherwise pericardial window
• Haemopericardium
• Any moderate-to-large effusion thought to be acute or increasing in size

Healthy patients with large, asymptomatic effusions and no evidence of tamponade or a specific aetiology:

• Minority can develop tamponade unpredictably
• May reaccumulate after closed pericardiocentesis
• There is a rationale for pericardial window, especially if no systemic inflammation, and therefore low chance of NSAIDs working

Comparison between closed and open pericardiocentesis

• Higher recurrence rate with closed (30% vs 1% recurrence)
• Higher complication rate with closed

Indications for pericardial window:

• Actual or threatened tamponade, especially if loculated or containing clots/fibrinous material
• Healthy patients with large, asymptomatic effusions, no known aetiology, and no systemic inflammation
• Traumatic haemopericardium