Constrictive Pericarditis: Pathophysiology, Causes, Symptoms, Diagnosis, Management and Prevention

Constrictive Pericarditis: Pathophysiology, Clinical Features, Diagnosis and Management

Constrictive pericarditis (CP) is a chronic pericardial disorder characterized by a thickened, fibrotic, and often calcified pericardial sac that restricts diastolic filling of the heart. This impaired cardiac filling leads to symptoms of systemic venous congestion, reduced cardiac output, and ultimately significant functional disability. Although once commonly associated with tuberculosis, modern cases are more often linked to idiopathic or postsurgical etiologies. Early diagnosis and appropriate intervention can dramatically improve outcomes, making it a crucial entity in cardiology.

~Introduction

The pericardium is a double-layered fibroserous sac surrounding the heart, comprising a visceral and parietal layer. In normal physiology, the pericardial space contains a small amount of lubricating fluid (10–50 mL) that facilitates frictionless cardiac movement. Constrictive pericarditis occurs when scarring, fibrosis, or calcification leads to loss of the pericardium’s elasticity. As a result, the heart becomes trapped within a rigid shell, inhibiting its ability to expand during diastole. This “constriction” causes equalization of diastolic pressures in all four chambers and produces hallmark clinical findings such as elevated jugular venous pressure (JVP), Kussmaul’s sign, peripheral edema, hepatomegaly, and ascites.

CP can be subtle and often mimics restrictive cardiomyopathy, chronic liver disease, or advanced heart failure. Hence, a deep understanding of its pathophysiology and diagnostic criteria is essential for proper differentiation.

~Etiology

1. Idiopathic or Viral

Idiopathic (unknown cause) and post-viral pericarditis account for almost 40–50% of cases in developed countries. Viral infections such as Coxsackievirus or echovirus can initiate acute pericarditis that eventually evolves into a chronic constrictive process.

2. Post-Cardiac Surgery

Open-heart surgical procedures—coronary artery bypass grafting (CABG), valve repair/replacement, or congenital heart repairs—can trigger an inflammatory reaction, leading to pericardial fibrosis.

3. Radiation Therapy

Chest radiation for malignancies such as Hodgkin lymphoma or breast cancer is a well-recognized cause. Radiation-induced pericardial fibrosis may develop years or even decades after exposure.

4. Tuberculosis

In many developing countries, tuberculosis remains one of the leading causes of constrictive pericarditis. Chronic pericardial infection results in granulomatous inflammation and dense calcification.

5. Connective Tissue Diseases

Autoimmune conditions like systemic lupus erythematosus, rheumatoid arthritis, and scleroderma may involve the pericardium.

6. Malignancies

Primary or metastatic cancers can invade the pericardium, causing chronic inflammation and subsequent constriction.

7. Trauma

Blunt or penetrating chest trauma, although relatively rare, may result in chronic pericardial scarring.

~Pathophysiology

The core abnormality in constrictive pericarditis is the loss of pericardial compliance. Fibrosis, scarring, and calcification create a stiff, non-expandable pericardial sac. As a result:

1. Impaired Ventricular Filling

During early diastole, ventricular filling occurs rapidly but halts abruptly when the rigid pericardium reaches its limit. This produces a characteristic dip-and-plateau pattern on hemodynamic tracings, also known as the “square root sign.”

2. Septal Bounce and Ventricular Interdependence

Because the pericardium restricts total cardiac volume, any increase in the filling of one ventricle during respiration leads to reduced filling of the other. This is called ventricular interdependence, seen prominently on echocardiography as a septal bounce.

3. Elevated Systemic Venous Pressure

Restricted diastolic filling causes blood to back up into systemic veins, leading to JVP elevation, edema, hepatomegaly, and ascites.

4. Equalization of Diastolic Pressures

Since all chambers are restricted, diastolic pressures in the right atrium, right ventricle, left atrium, and left ventricle typically equalize (within 5 mm Hg).

5. Reduced Cardiac Output

Limited filling during diastole reduces stroke volume and cardiac output, resulting in fatigue and exercise intolerance.

~Clinical Features

The presentation of CP may be subtle and develop gradually over months or years.

Symptoms

1. Dyspnea on exertion – due to decreased cardiac output.

2. Fatigue and exercise intolerance – from reduced stroke volume.

3. Abdominal distension – due to ascites.

4. Peripheral edema – a hallmark of systemic congestion.

5. Right upper quadrant discomfort – from hepatic congestion.

6. Anorexia, nausea – secondary to congestion of abdominal organs.

Signs

1. Elevated Jugular Venous Pressure (JVP)
   Often prominent and accompanied by Kussmaul’s sign—a paradoxical rise in JVP during inspiration.

2. Pericardial Knock
   A high-pitched early diastolic sound caused by abrupt cessation of ventricular filling.

3. Hepatomegaly
   Congestive hepatopathy may progress to cardiac cirrhosis.

4. Ascites and Peripheral Edema
   Often disproportionate to the degree of pulmonary congestion.

5. Pulsus Paradoxus
   Less common in CP (more typical of tamponade) but can be present in mixed physiology.

6. Cachexia
   Seen in long-standing cases due to chronic illness.

~Diagnostic Evaluation

A combination of clinical suspicion, imaging, and hemodynamic studies is required.

1. Laboratory Tests

Laboratory findings are usually nonspecific but may show:

• Mild elevation of liver enzymes

• Hypoalbuminemia

• Elevated BNP, although usually lower compared to restrictive cardiomyopathy

2. Chest X-ray

• May reveal pericardial calcification, especially in tuberculosis.

• Cardiomegaly is typically absent unless accompanied by effusion.

3. Electrocardiogram (ECG)

• Low voltage QRS complexes

• Non-specific T-wave changes

• Atrial fibrillation in some patients due to chronic atrial stretch

4. Echocardiography

Echocardiography is essential and reveals:

• Septal bounce (interventricular dependence)

• Respiratory variation in mitral and tricuspid inflow

• Plethoric IVC with reduced collapse during inspiration

• Pericardial thickening (not always visible)

5. CT and MRI

These provide high-resolution anatomical detail.

CT Scan:

• Excellent at detecting pericardial calcifications

• Measures pericardial thickness (>4 mm is abnormal)

Cardiac MRI:

• Best imaging modality for tissue characterization

• Identifies pericardial fibrosis, inflammation, and thickness

• Reveals diastolic septal bounce and ventricular interdependence

6. Cardiac Catheterization

The gold standard when diagnosis is uncertain.

Findings include:

• Equalization of diastolic pressures

• Square root sign in ventricular pressure tracings

• Discordant ventricular pressure changes with respiration

Differentiation from Restrictive Cardiomyopathy

An important distinction because treatment differs.

Feature	Constrictive Pericarditis	Restrictive Cardiomyopathy
Pericardial thickness	Increased	Normal
JVP with Kussmaul sign	Common	Common
Septal bounce	Present	Absent
Respiratory variation in inflow	Marked	Minimal
BNP levels	Mild elevation	Very high
Treatment	Pericardiectomy	Medical therapy mostly

~Complications

1. Chronic hepatic congestion → cardiac cirrhosis

2. Progressive right-sided heart failure

3. Atrial arrhythmias (especially atrial fibrillation)

4. Cachexia

5. Renal dysfunction due to low cardiac output

~Management

1. Medical Therapy

Medical treatment does not cure constrictive pericarditis but may help temporarily in early or transient cases.

Transient Constriction:
Occurs after acute pericarditis and may resolve with anti-inflammatory therapy.

Drugs include:

• NSAIDs

• Colchicine

• Corticosteroids (for autoimmune or inflammatory cases)

• Diuretics (to control edema and ascites)

Diuretics must be used cautiously to avoid excessive preload reduction.

2. Surgical Therapy — Pericardiectomy

Definitive treatment for chronic constrictive pericarditis.

Pericardiectomy involves removal of the parietal and often visceral pericardium.

Indications

• Persistent symptoms despite optimal medical management

• Evidence of chronic constriction on imaging/hemodynamics

• Severe functional limitation (NYHA class III–IV)

Outcomes

• Success depends on etiology (best outcomes in idiopathic cases)

• Higher risk in radiation-induced and calcific tuberculosis cases

• Mortality ranges 5–15% depending on severity and comorbidities

Postoperative improvement may take months as the heart remodels.

~Prognosis

Prognosis of constrictive pericarditis varies widely:

• Idiopathic/Viral: Excellent prognosis post-pericardiectomy

• Post-surgical: Good, depending on comorbidities

• Tuberculous: Reasonably good if treated early

• Radiation-induced: Poor prognosis due to associated myocardial and valvular damage

Delayed diagnosis is a major contributor to functional impairment and reduced survival.

~Prevention

1. Prompt treatment of acute pericarditis

2. Avoid unnecessary radiation exposure

3. Early management of tuberculosis

4. Monitoring patients post-cardiac surgery

~Conclusion

Constrictive pericarditis is a unique and challenging cardiovascular condition characterized by restricted cardiac filling due to a rigid, fibrotic pericardium. Its clinical presentation often overlaps with other causes of heart failure and systemic congestion, making early recognition essential. A combination of clinical signs such as elevated JVP with Kussmaul’s sign, imaging findings like a septal bounce, and hemodynamic evidence of equalized diastolic pressures aids in establishing the diagnosis. Although medical therapy may help in transient forms, chronic constrictive pericarditis requires pericardiectomy—the only definitive cure. With timely diagnosis and appropriate intervention, many patients can achieve significant symptomatic improvement and regain good quality of life.