Constrictive pericarditis is a potentially curable entity in patients with heart failure and normal ejection fraction; however, it is not well appreciated and is underdiagnosed because of the difficulty in differentiating it from restrictive cardiomyopathy or other entities responsible for predominantly right-sided heart failure. Even after extensive testing with 2-dimensional and Doppler echocardiography, cardiac CT and CMR, and conventional cardiac catheterization, the diagnosis may remain equivocal.81-83
However, with new insights and advances in noninvasive imaging, a definitive diagnosis of pericardial constriction is becoming easier to establish.
Constrictive pericarditis can occur after any pericardial disease process. In developed nations, idiopathic causes and cardiac surgery are the 2 most predominant underlying etiologies, followed by pericarditis and mediastinal radiation therapy.83,84
In developing and underdeveloped nations, as well as in immunosuppressed patients, tuberculosis is a major cause of constrictive pericarditis.85
Miscellaneous causes of constrictive pericarditis include connective tissue disorder, malignancy, trauma, medications, asbestosis, sarcoidosis, and uremic pericarditis.
Restrictive cardiomyopathy, a rarer disorder, is often seen in patients with a systemic disorder, such as amyloidosis, sarcoidosis, hypereosinophilic syndromes, endomyocardial fibrosis, and disorders caused by chemotherapy or radiation. Restrictive hemodynamic features without restrictive cardiomyopathy can also arise in any myocardial disease, including hypertrophic, dilated, hypertensive, and ischemic heart disease.
Both constrictive pericarditis and restrictive cardiomyopathy limit diastolic filling and result in diastolic heart failure, with relatively preserved global systolic function. In constrictive pericarditis, diastolic filling is restricted by an inelastic pericardium after an initial expansion of the myocardium. The upper limit of ventricular volume is constrained by an inflamed, scarred, or calcified pericardium (, left) that is usually, but not always, thicker than normal.1,86,87
Restrictive cardiomyopathy (, right) is defined by a nondilated ventricle with a rigid myocardium that causes a major decrease in the effective operative compliance of the heart muscle itself.88
This decrease distinguishes it from constrictive pericarditis, in which no such decrease in myocardial compliance is usually seen.
FIGURE 12. Gross pathological features of constrictive pericarditis and restrictive cardiomyopathy. Left, Heart specimen of a patient who died with constrictive pericarditis. The pericardium is thickened and calcified; fibrosis and adhesion of the pericardial layers (more ...)
History. A history of cardiac surgery or a systemic disease that affects the pericardium makes the diagnosis of
constrictive pericarditis more likely, whereas a history of an infiltrative disease that may involve the heart muscle favors the diagnosis of restrictive cardiomyopathy. In both conditions, the most common symptoms are related to either fluid overload (eg, peripheral edema, elevated central venous pressure, hepatomegaly, pleural effusion, ascites, and anasarca) or decreased cardiac output (eg, dyspnea on exertion, fatigue, palpitations, weakness, and exercise intolerance) ().
FIGURE 13. Overview of the diagnosis and management of constrictive pericarditis. ACE = angiotensin-converting enzyme; ECG = electrocardiography; IVC = inferior vena cava; JVP = jugular venous pressure; LV = left ventricle; NSAID = nonsteroidal anti-inflammatory (more ...)
Physical Examination. The cardiovascular examination may not differentiate constrictive pericarditis from restrictive cardiomyopathy. The jugular venous pressure is always elevated in constrictive pericarditis with a deep, steep y descent. Evidence of Kussmaul sign and a pericardial knock favor constrictive pericarditis. However, a pericardial knock may be difficult to distinguish from an S3 because the origin of a pericardial knock and S3 is similar in that the ventricular wall vibrates with rapid early diastolic filling. Both coincide with the nadir of the y descent. Pulsus paradoxus, a finding in tamponade, is uncommon in constrictive pericarditis.
Electrocardiography. Electrocardiography may assist in distinguishing constrictive pericarditis from restrictive cardiomyopathy but is never diagnostic. Nonspecific ST-segment and T-wave changes are common features of constrictive pericarditis, whereas low QRS voltage and isolated repolarization abnormalities are more typical in constrictive pericarditis. Depolarization abnormalities, such as bundle branch block, ventricular hypertrophy, pathologic Q waves, and impaired atrioventricular conduction, strongly favor restrictive cardiomyopathy. Late-stage atrial fibrillation can occur in both conditions.
Calcification of the pericardium (63
) strongly suggests constrictive pericarditis in patients with heart failure. It is best seen from a lateral view and located over the RV and diaphragmatic surfaces of the heart. In our most recent review,22
only 25% of patients with constrictive pericarditis were found to have pericardial calcification on chest radiography. Pericardial calcification is associated with a longer duration of the constrictive process but not with a specific etiology. Therefore, absence of calcification does not exclude constrictive pericarditis.
FIGURE 14. Chest radiograph, transesophageal echocardiogram (TEE), and cardiac computed tomogram typical of constrictive pericarditis. A, Pericardial calcification (arrows) on chest radiography is best seen from the lateral view over the right ventricle (RV) and (more ...) Echocardiography.
Echocardiography is usually the initial diagnostic imaging and hemodynamic study in patients with suspected constrictive pericarditis. Its diagnostic accuracy for constrictive pericarditis has increased since characteristic hemodynamic changes and mitral annulus motion were identified. Left ventricular systolic function as judged by the ejection fraction is typically normal but may be impaired in mixed constrictive-restrictive disease. The following findings may be present with echocardiography in constrictive pericarditis1,7,89-94
: (1) increased pericardial thickness (measured with greater sensitivity by transesophageal echocardiography and cardiac CT than transthoracic echocardiography [63
]); however, constrictive pericarditis can occur without increased pericardial thickness; (2) abnormal ventricular septal motion; (3) dilatation and absent or diminished collapse of the IVC and hepatic veins; (4) restrictive mitral and tricuspid inflow velocities, typically (but not always) with respiratory variation (63
); (5) preserved or increased medial mitral annulus early diastolic (e′) velocity (), which is an important
distinction from restrictive cardiomyopathy in which the e′ is diminished with a cutoff value of 7 cm/s95
; and (6) increased hepatic vein flow reversal with expiration, reflecting the ventricular interaction and the dissociation of the intracardiac and intrathoracic pressures (63
FIGURE 15. Schematic diagram of Doppler echocardiographic features in constrictive pericarditis vs restrictive cardiomyopathy. Schematic illustration of Doppler velocities from mitral inflow (MV), mitral annulus velocity, and hepatic vein (HV). Electrocardiographic (more ...)
In restrictive cardiomyopathy, the mitral inflow velocity rarely shows respiratory variation, and hepatic vein systolic flow reversals are more prominent with inspiration. Therefore, invasively or noninvasively, the differentiation of restriction from constriction should be based on the respiratory patterns of ventricular filling. Measurement of septal mitral annular velocity by Doppler tissue imaging also helps distinguish constriction from restriction. Mitral annular velocity is markedly decreased in restrictive cardiomyopathy because myocardial relaxation is reduced in myocardial diseases. In contrast, it is well preserved or even augmented in constrictive pericarditis because the longitudinal motion of the heart is the main mechanism of diastolic filling in this condition (63
Cardiac CT and CMR
Computed tomography is useful in diagnosing constrictive pericarditis and can demonstrate increased pericardial thickness (>4 mm) and calcification1,22
). Inferior vena cava dilatation, deformed ventricular contours, and angulation of the ventricular septum can be seen. In addition, failure of the immediately adjacent pulmonary structures to pulsate during the cardiac cycle in the presence
of a thickened pericardium is highly suggestive of constrictive physiology. However, almost 20% of patients with surgically proven constrictive pericarditis did not have increased pericardial thickness on cardiac CT.22
Therefore, the lack of increased pericardial thickness does not exclude the diagnosis of constriction. Cardiac magnetic resonance imaging has been shown to be useful in detecting increased pericardial thickness and dilatation of the IVC.
Invasive Hemodynamic Evaluation of Constrictive Pericarditis vs Restrictive Cardiomyopathy
Despite the difference in the pathophysiologic mechanisms of restriction and constriction, considerable overlap is seen in the invasive hemodynamic parameters of these 2 entities. Increased atrial pressures, equalization of end-diastolic pressures, and dip-and-plateau or square-root sign of the ventricular diastolic pressure recording have traditionally been considered hemodynamic features typical of constrictive pericarditis. However, almost identical hemodynamic pressure tracings can be obtained in patients with restrictive cardiomyopathy. Therefore, in addition to these hemodynamic features, respiratory variation in ventricular filling and increased ventricular interdependence should be demonstrated to diagnose constriction, either invasively or noninvasively.96,97
In both conditions, a high driving pressure across the valves at the time of atrioventricular valve opening results in early rapid diastolic filling and an abrupt increase in ventricular pressure. In constrictive pericarditis, once the volume of ventricular filling approximates what the diseased pericardium allows in mid to late diastole, the filling of the heart chambers stops abruptly because the fixed and stiffened pericardial sac cannot stretch any further. As a result, the predominantly ventricular filling occurs rapidly in the first third of diastole, and neither ventricular chamber fills to any substantial amount in mid to
end diastole. This leads to the hemodynamic signs of dip (the rapid y
descent in the jugular venous pressure) and plateau during right heart catheterization, a phenomenon known as the square-root sign
. As a consequence of these limitations, there is an elevation and near equalization of diastolic pressures in the RA, RV, and pulmonary wedge pressure, which corresponds to the left heart diastolic pressure.84
However, the 2 pressures are not precisely equal throughout the respiratory cycle; the pulmonary wedge pressure decreases during inspiration, whereas the systemic venous pressure remains constant. In restrictive cardiomyopathy, stiff ventricular walls result in severe diastolic dysfunction and restrictive filling, with elevated filling pressures similar to those in constrictive pericarditis. Restrictive cardiomyopathy may have similar findings of elevation with end-equalization of diastolic pressures in all 4 cardiac chambers.
Respiratory Changes in Ventricular Filling
The most specific hemodynamic feature of constrictive pericarditis is enhanced ventricular interdependence, manifested as a discordant change in the total area of the LV and RV systolic pressure curve with respiration97
(). Respiratory variation in the filling of the LV and RV occurs in patients with constrictive pericarditis but not in those with restrictive cardiomyopathy.96,97
In the heart with a normal pericardium, inspiration causes a decrease in intrathoracic pressure, with some increase in filling of the RV due to enhanced venous return. Filling of the LV is unaffected throughout the cardiac cycle because the decrease in intrathoracic pressure with inspiration is transmitted to intracardiac chambers to maintain relatively the same driving pressure gradient from the pulmonary circulation to the left-sided chamber throughout different respiratory phases. However, in a patient with constrictive pericarditis, the rigid pericardium does not allow the decrease in intrathoracic pressure to be transmitted to the heart chambers, causing a decrease in the driving pressure gradient from the pulmonary circulation to the left-sided chambers with inspiration. With a constant combined cardiac volume, the reduction in LV filling allows increased RV filling with inspiration. During inspiration, the RV filling cannot expand into the free wall because of the rigid pericardium. As a consequence, the interventricular septum shifts toward the LV, but the total cardiac volume does not change. During expiration, conversely, LV filling is increased. Hence, the left septum shifts toward the RV, and RV filling decreases. In patients with restrictive cardiomyopathy or other myocardial diseases with biventricular failure, these findings are absent, and the area of the LV and RV systolic pressures changes concordantly during the respiratory cycle ().
FIGURE 16. Ventricular interdependence and respiratory variation in ventricular filling in constrictive pericarditis and restrictive cardiomyopathy. Ventricular interdependence is observed in simultaneous recordings of left ventricular (LV) and right ventricular (more ...)
In patients with transient constrictive pericarditis caused by pericardial inflammation, symptoms and constrictive features may resolve with medical therapy alone.98,99
In chronic constrictive pericarditis, surgery is the accepted standard.83,100-102
However, pericardiectomy is associated with a significant operative mortality of greater than 6% at most experienced centers.83,100
The largest surgical series indicate that independent adverse predictors of long-term outcome include older age, worse New York Heart Association class, renal dysfunction, pulmonary hypertension, LV dysfunction, hyponatremia, and prior ionizing radiation.83,100
Because the symptoms of constrictive pericarditis may persist after partial pericardiectomy, it is important that the pericardiectomy is complete, with as much of the pericardium removed as possible.