Chronic constrictive pericarditis is a condition caused by chronic inflammatory lesions of the pericardium, leading to pericardial thickening, adhesion, and even calcification. These changes restrict cardiac diastolic function and result in systemic circulatory disorders.
Etiology
Historically, most cases of chronic constrictive pericarditis were caused by tuberculous pericarditis. However, cases of tuberculous constrictive pericarditis have significantly decreased in prevalence. In the majority of cases today, the underlying cause is unknown.
Pathophysiology
In chronic constrictive pericarditis, the visceral and parietal layers of the pericardium are thickened due to chronic inflammation, forming rigid fibrous scar tissue. In some cases, calcification occurs within the scar tissue, resulting in calcified plaques embedded in the myocardium or forming a calcified shell encasing the heart. The thickened, rigid pericardium constrains the heart, significantly limiting its diastolic function. This reduces the volume of blood filling the heart, obstructs venous return, and increases systemic venous pressure, leading to organ congestion throughout the body.
Additionally, reduced ventricular filling decreases the cardiac output. Chronic restriction by the scar tissue causes myocardial atrophy and reduces myocardial contractility, further lowering cardiac output and leading to inadequate blood supply to various organs. Reduced renal perfusion exacerbates sodium and water retention, increasing blood volume and venous pressure. This contributes to signs of systemic venous congestion such as hepatomegaly, ascites, pleural effusion, and lower extremity edema. Pulmonary circulation may also be affected, with obstructed pulmonary venous return resulting in pulmonary congestion, and increased pulmonary venous and arterial pressures.
Clinical Manifestations
Primary manifestations reflect right heart failure. Common symptoms include fatigue, weakness, cough, dyspnea, abdominal fullness, and poor appetite. Dyspnea typically occurs after exertion, but if there is significant pleural effusion or diaphragm elevation due to ascites, dyspnea may also occur at rest. Severe pulmonary congestion may lead to orthopnea.
Physical Examination: Findings include jugular vein distension, hepatomegaly, ascites, and lower extremity edema. Cardiac impulses are weakened or absent, and the cardiac dullness area does not usually increase. Heart sounds are distant, and the heart rhythm is typically normal, though rapid, small pulses and pulsus paradoxus may be observed. Systolic blood pressure is often low, with a narrow pulse pressure. Venous pressure is typically elevated, ranging from 1.9 to 3.9 kPa (20–40 cmH2O). Chest examination may reveal unilateral or bilateral pleural effusion.
Auxiliary Examinations
Laboratory Tests
Findings may include mild anemia, normal or slightly elevated erythrocyte sedimentation rate, mildly reduced liver function, and decreased serum albumin levels.
Electrocardiogram (ECG)
ECG findings often show low-voltage QRS complexes across all leads, with flattened or inverted T waves. Atrial fibrillation may be observed in some cases.
X-ray Examination
Cardiac silhouette size is typically normal, with straightened left and right cardiac borders and a reduced aortic arch. Cardiac pulsation may be weakened or absent. Calcification in the pericardium is often visible in oblique or lateral views. Chest X-rays may also reveal pleural effusion.
CT and MRI
CT and MRI imaging can clearly show the location, extent, and degree of pericardial thickening and calcification, aiding in differential diagnosis.
Echocardiography
Echocardiography may demonstrate pericardial thickening, adhesion, or effusion, as well as atrial enlargement, ventricular shrinkage, and weakened cardiac function.
Diagnosis
Diagnosis is typically straightforward based on the history, clinical signs, and echocardiographic findings. Differential diagnosis should consider cirrhosis, congestive heart failure, and restrictive cardiomyopathy. CT imaging can provide detailed information on the thickness, extent, and calcification of the pericardium.
Treatment
Management of confirmed constrictive pericarditis involves surgical intervention. Preoperative measures focus on improving nutritional status, correcting electrolyte imbalances, treating hypoproteinemia and anemia, and providing a low-sodium diet with diuretics.
Surgical treatment typically involves a median sternotomy. The procedure begins with the excision of thickened fibrous pericardial tissue in the anterior left ventricular region. Once the visceral pericardium is incised to expose the myocardium, the myocardium is observed to bulge outward and exhibit strong pulsations. The procedure continues with careful stripping of the pericardium from the anterior wall of the left ventricle and the apex, followed by release of the right ventricle. The extent of pericardiectomy includes reaching the phrenic nerves on both sides, extending superiorly beyond the base of the great vessels and inferiorly to the diaphragmatic pericardium.
In some cases, scar tissue rings at the entry points of the superior and inferior vena cava may need to be excised. Care is taken to avoid damage to myocardial and coronary structures during pericardial stripping. Calcified plaques embedded in the myocardium may be left in situ if removal risks damage. Following pericardiectomy, there are immediate improvements in cardiac diastolic and systolic function, reduced venous pressure, and increased venous return. The fluid previously stagnant in the tissues re-enters the circulation, arterial pressure increases, and pulse pressure widens.
Because the cardiac workload increases, supportive measures such as inotropes and diuretics may be required as needed. Postoperative care includes close monitoring of cardiac, pulmonary, and renal function. Fluid infusion volumes are controlled to maintain balance, and careful attention is given to water and electrolyte homeostasis.