Constrictive Pericarditis

Selected images from cardiac MRI: (First 4 images are A-D respectfully) Short axis GRE cine (Fig. A) and 4-chamber GRE cine (Fig. B) images reveal concentric pericardial thickening, estimated at approximately 7 mm in thickness, over the right ventricular free wall. The right ventricle is adherent to the parietal pericardium. There is mild right atrial dilatation but no significant deformity of the heart. These images, as well as the real-time provocative 4-chamber (Fig. C) and short axis (Fig. D) cine GRE images obtained while the patient takes in a deep breath (note the motion), show abnormal ventricular coupling manifest by pronounced septal displacement during deep inspiration (“septal bounce”). Post-contrast phase-sensitive inversion recovery (PSIR) 4-chamber (Fig. E and F) and short-axis (Fig. G and H) images demonstrate enhancement of the thickened pericardium.     Diagnosis: Constrictive Pericarditis

Differential Diagnosis

None

 

Background

Discussion

The normal pericardium is composed of 2 layers: a tough fibrous parietal pericardial layer and a smooth visceral pericardial layer. Approximately 50 mL of transudative fluid is normally present between these 2 layers (i.e., intrapericardial space) which minimizes friction during the cardiac cycle. Inflammation of the pericardial layers is referred to as pericarditis. Acute and subacute pericarditis may be associated with fibrin deposition along these pericardial layers and a concomitant pericardial effusion. Subsequent organization results in fibrosis, scarring, and sometimes calcification, most often of the parietal pericardium. The thickened, fibrotic pericardium then impairs normal late diastolic filling of the ventricle. Approximately 9% of patients with acute pericarditis go on to develop constrictive physiology such as demonstrated in this case.

 

Etiology

Those clinical entities associated with acute pericarditis are likewise responsible for the development of constrictive pericarditis. These most commonly include: idiopathic (presumably viral) (e.g., coxsackievirus A and B, adenoviruses); tuberculosis; following cardiac surgery; and radiation-therapy induced. Less common causes include: neoplasia; uremia; various connective tissue disorders (e.g., rheumatoid arthritis, systemic lupus erythematosus, scleroderma); drug-induced (e.g., Procainamide, Hydralazine); and following myocardial infarction.

 

Clinical Findings

Dyspnea is the most common presenting symptom in virtually all patients. Fatigue and orthopnea are not uncommon. Patients may also experience lower extremity edema. Unexplained jugular venous distention, pleural effusion, hepatomegaly, and or ascites may be evident on physical exam. Kussmaul sign (ie, elevation of systemic venous pressures with inspiration) is a common but nonspecific finding.

 

Imaging Findings

Conventional Radiography

• May be normal
• Pericardial calcification (20-30% patients)
• Pericardial calcification may be present without constrictive physiology
• Constrictive physiology may be present without pericardial calcification
• +/- Widened vascular pedicle
• Pleural effusion(s); common

MDCT

• May be normal
• Normal pericardium thickness:1-2 mm
• Abnormal pericardial thickness: ≥3-4 mm
• CT superior to MRI in detecting associated pericardial calcification, however, MRI superior to CT in demonstrating associated physiologic abnormalities
• Impaired right ventricular filling may manifest as:
• Distention of inferior vena cava, hepatic veins, right atrium, coronary sinus
• Hepatosplenomegaly
• Ascites
• +/- Normal right ventricular size but abnormal tubular morphology (tubularization)

MRI

• Sensitive for imaging the pericardium and measuring pericardial thickness (Fig. A-H)
• Adherence of visceral and parietal pericardium (Fig. A and B)
• +/- Normal right ventricular size but abnormal tubular morphology (tubularization)
• As with CT, may see signs of impaired right ventricular filling (Fig. A-H)
• Real-time imaging provides more “direct method” of visualizing altered physiology
• Paradoxical septal bounce ("shivering septum") (Fig. A-D)
• Present in up to 85% of patients with constrictive pericarditis (Fig. A-D)
• Deep inspiration shows abnormal ventricular interdependence such that augmentation of RV filling results in right-to-left septal displacement; absent in patients with restrictive cardiomyopathy (Fig. C-D)
• Delayed-enhancement imaging may show focal or diffuse pericardial enhancement (Fig. E-H)

Treatment

Surgical pericardiectomy is the procedure of choice in the appropriate patient.  However, in cases where constriction has been present for a prolonged period of time, the response may be less dramatic, due to the development of extensive atrophy and fibrosis.

 

Prognosis

Symptoms following pericardiectomy commonly improve, but evidence of abnormal diastolic filling often remains. Only 60% of patients have complete normalization of cardiac hemodynamic function.

 

Caveats

• Normal pericardial thickness does not exclude underlying constrictive pericarditis
• A thickened pericardium does not indicate a given patient has constrictive pericarditis; the imaging finding must be correlated with the clinical signs and symptoms
• MR is useful in distinguishing constrictive pericarditis from restrictive cardiomyopathy; conditions which have very similar clinical presentations

Selected Readings

1. Breen JF. Imaging of the pericardium.  J Thorac Imaging 2001; 16(1):47-54.
2. Francone, M., et al., Assessment of ventricular coupling with real-time cine MRI and its value to differentiate constrictive pericarditis from restrictive cardiomyopathy. Eur Radiol 2006; 16(4): 944-951.
3. Grizzard JD, Ang GB. Magnetic resonance imaging of pericardial disease and cardiac masses. Cardiol Clin 2007; 25(1):111-140.
4. Srichai, MB, Axel L. Magnetic resonance imaging in the management of pericardial disease.  Curr Treat Options Cardiovasc Med 2005; 7(6): 49-57.