Asher Weisberg and Michael Wait
This chapter is a revision and update of that included in previous editions of the TSRA Review written by Salvior Mok (2nd edition) and Gabriel Loor (1st edition).
Anatomy
The pericardium is a conical fibroserous sac made up of two intimately connected layers (visceral and parietal) that cover the heart and origins of the great vessels. The transverse and oblique sinuses exist by virtue of the anatomic reflection of the pericardium. The normal volume of pericardial fluid is 15-20 mL. Its normal pressure ranges from -5 to +5 mmHg. The parietal pericardium is covered by fibroelastic tissue (fibrosa), which determines its compliance. The hemodynamic influence of pericardial disease is related to the potential limitation of diastolic filling.
Pericardial effusion
A pericardial effusion is defined as an abnormal increase in the volume of pericardial fluid. Contrary to cardiac tamponade, a gradual accumulation of fluid allows elastin fibers to adjust, resulting in a stable rise in pressure and a greater volume capacity.
The three most common etiologies of pericardial effusion and pericarditis are neoplasia, uremia, and idiopathic. Pericardial effusions may be transudative, exudative, chylous, hemorrhagic or purulent. Exudative fluid is characterized by LDH >200 U/L (or >0.6 times the serum LDH), protein >0.5 times the serum protein, or cholesterol level >45 mg/dL. Chylous effusions are rare and usually the result of trauma or iatrogenic injury causing abnormal connections between the thoracic duct or lymphatic vessels and the pericardium. They are milky and contain >110 mg/dL of triglycerides. They are generally treated conservatively with initial percutaneous drainage, NPO and TPN, but may require thoracic duct ligation or mediastinal exploration in refractory cases.
Symptoms of pericardial effusion include dyspnea, chest pressure, or tamponade. Echocardiography, which is considered the gold standard for diagnosis of tamponade, will show right ventricular indentation during early diastole, as well as compression of the RV free wall during late diastole-early systole lasting more than one-third of the cardiac cycle. CXR will show an enlarged cardiac silhouette when an effusion is at least 250 mL. CT scans and MRIs may also reveal the presence of effusions. Cardiac catheterization can aid in the diagnosis of tamponade or pericardial constrictive disease.
Pericarditis
Pericarditis is an inflammation of the pericardial sac, producing a serofibrinous exudate on the pericardium that may develop an effusion. A classic presentation for pericarditis is pleuritic chest pain relieved by leaning forward. Other findings include a pericardial friction rub heard on auscultation, and diffuse ST elevations on ECG. It must be differentiated from acute MI, which produces more regionalized ECG abnormalities.
Infective pericarditis
- Viral pericarditis. Caused by Coxsackie virus B (most common), Echovirus, Adenovirus, Influenza virus, mumps, varicella, EBV, or hepatitis B virus. It is sometimes diagnosed as “idiopathic pericarditis.” It is usually self-limiting, resolves within 1-3 weeks, or even subclinical in healthy individuals. Treatment is supportive with NSAIDs +/- colchicine. Large effusions are rare and should be drained only for symptoms or diagnostic uncertainty.
- Bacterial pericarditis. Can be life threatening. Most commonly due to Streptococcal, Pneumococcal, or Staphylococcal organisms. Treatment is with antibiotics. Purulent effusions may contribute to refractory sepsis and even tamponade; often require surgical drainage through a pericardial window.
- Tuberculous pericarditis. Historically, a major cause of infective pericarditis. It results in an exudative pericardial inflammation in the setting of an active TB infection. It is characterized by fibrinous exudate followed by serosanguinous effusions, which resorb and organize into caseating granulomas, pericardial thickening, fibrosis and constriction. Management is triple drug therapy but bloody effusions may develop that require drainage for symptoms and prevention of constrictive pericarditis in the future.
- Fungal pericarditis. Treated with antifungals and NSAIDs.
Neoplastic pericarditis
Commonly due to tumors of the breast, lung, and lymphoma, as metastatic disease or contiguous spread. Management is palliation with pericardiocentesis, pericardial window +/- talc or doxycycline sclerotherapy. Patients with malignant effusions have a median survival of 2 to 3 months.
Metabolic causes
Uremic pericarditis usually resolves within 2 weeks of aggressive dialysis. Drainage is reserved for large, symptomatic or refractory effusions.
Other causes
Myxedema, immunologic disorders, myocardial infarction, cirrhosis, heart failure, drugs, and idiopathic. Rheumatoid arthritis and RT exposure may also result in pericarditis +/- effusions but are generally more important in their contribution to constrictive pericarditis. Procainamide, hydralazine, methylsergide, emetine, and minoxadil are drugs classically associated with pericarditis.
- Dressler’s syndrome. As opposed to postinfarction pericarditis that occurs in 50% of patients suffering a transmural MI in the first 24-72 hours, Dressler’s syndrome is a diffuse pleuropericardial inflammation with an autoimmune etiology that occurs weeks to months after an MI. It does not generally require drainage. It is treated supportively with NSAIDs +/- colchicine.
Cardiac tamponade
Tamponade is a feared complication of open heart procedures, trauma, or complex pericarditis. It occurs when intrapericardial pressure impedes diastolic filling, causing increased venous pressure, decreased cardiac output, shock, and death if left untreated. Acute compensatory measures include tachycardia, elevated systemic and pulmonary venous tone.
Cardiac tamponade in a postoperative patient presents with a drop in cardiac index, oliguria, elevated filling pressures, worsening acidosis, hemodynamic instability, increased inotrope or pressor dependence, and narrowed pulse pressure. The classic Beck’s triad (hypotension, JVD and muffled heart sounds) may or may not be present. Other signs are pulsus paradoxus (decrease in systolic blood pressure by 10 mmHg with inspiration) and equilibration of diastolic pressures. There may be a loss of y-descent on the venous tracing (loss of passive flow from the atrium to the ventricle during early diastole). Echocardiography shows the effusion and a lack of IVC collapse with inspiration. Postoperative cardiac tamponade, however, should be a clinical diagnosis. Treatment requires evacuation via pericardiocentesis (subacute/chronic thin effusion), pericardial window (loculated effusion, subxiphoid/transpleural approach), median sternotomy (acute post-operative), or clamshell incisions depending on the clinical situation and urgency.
Constrictive pericarditis
The pathophysiology of constrictive pericarditis is limited cardiac filling. The most common etiology in Western countries is idiopathic, followed by prior cardiac surgery and mediastinal radiation, whereas TB is the most common cause of constrictive pericarditis in the developing world.
Distinguishing between cardiac tamponade and constrictive pericarditis is important (Table 86-1). Patients with constrictive pericarditis may have worsened JVD during inspiration (Kussmaul’s sign). Prominent S3 heart sound (pericardial knock) is due to rapid ventricular filling during diastole. Signs of low cardiac output (fatigue, hypotension, tachycardia) and elevated venous pressures (hepatomegaly, edema, ascites, shortness of breath on exertion) may be present.
Table 86-1. Comparison of clinical features of cardiac tamponade and constrictive pericarditis
| Tamponade | Constrictive pericarditis | |
| Pulsus paradoxus | Usually present | Present 1/3 of time |
| Equal left- and right-sided filling pressures | Present | Present |
| Systemic venous wave morphology | Absent y descent | Prominent y descent |
| JVD on inspiration | Decreased/unchanged | Increased (Kussmaul sign) |
| ‘Square root’ sign in ventricular tracing | Absent | Present |
Another important clinical distinction is between constrictive pericarditis and restrictive cardiomyopathy, which has several causes including sarcoidosis, amyloidosis, hemochromatosis, and radiation. Evaluation is based on clinical presentation and imaging studies including MRI, EKG, biopsy, and right heart catheterization.
Right and left heart catheterization remains the gold standard in the diagnosis of constrictive pericarditis, where equalization of end-diastolic pressures in all chambers and PA are seen. RV end-diastolic pressure should be greater than 1/3 of RV systolic pressure (95% sensitivity for the diagnosis of constrictive pericarditis). The “square root” sign is seen on ventricular tracing (rapid early diastolic filling of the ventricle followed by lack of additional filling due to compression in late diastole). Right atrial tracing demonstrates a prominent y descent.
Pericardial calcification on CXR is seen in 40% of patients with constrictive pericarditis. MRI shows a thickened pericardium and is more sensitive and specific than CT. Echocardiography shows displacement of the interatrial septum toward the left atrium during inspiration and septal bounce (abrupt end to ventricular filling).
First-line medical treatment for symptom relief for constrictive pericarditis includes NSAIDs and colchicine (to prevent recurrence). Pericardiectomy should be considered in patients with refractory or relapsing pericarditis. The procedure performed is radical pericardiectomy, which is defined as removal of the anterior, inferior, and left lateral pericardium posterior to the left phrenic nerve. The most common failure of surgical intervention is due to adhesive epicarditis, a thin nearly translucent layer on the pericardial surface which persists after pericardiectomy. Safe removal of this layer may be aided by the use of cardiopulmonary bypass.
Historically, pericardiectomy had a high morbidity and mortality, but a single-center study from the Mayo Clinic demonstrated improved outcomes in the modern era. The most common complications in their study were atrial arrhythmias in 13%, and prolonged ventilation in 11%. They demonstrated a perioperative mortality rate of 2.3%. Low LV EF and perioperative renal insufficiency were associated with an increased risk for perioperative mortality. Survival at 5, 10, and 15 years was 80%, 60%, and 38% respectively.
Suggested Readings
- Gillaspie EA, Stulak JM, Daly RC, et al. A 20-year experience with isolated pericardiectomy: Analysis of indications and outcomes. J Thorac Cardiovasc Surg. 2016;152(2):448-58.
- Adler Y, Charron P, Imazio M, et al. 2015 ESC Guidelines for the diagnosis and management of pericardial diseases: The Task Force for the Diagnosis and Management of Pericardial Diseases of the European Society of Cardiology (ESC)Endorsed by: The European Association for Cardio-Thoracic Surgery (EACTS). Eur Heart J. 2015;36(42):2921-2964.
