You are in: eMedicine Specialties > Radiology > CARDIAC Constrictive PericarditisArticle Last Updated: Jul 24, 2007AUTHOR AND EDITOR INFORMATIONSection 1 of 12
  Author: John S To, MD, Consulting Staff, Department of Radiology, Dickinson County Healthcare System John S To is a member of the following medical societies: Alpha Omega Alpha, American College of Radiology, American Medical Association, American Roentgen Ray Society, Massachusetts Medical Society, Michigan State Medical Society, and Radiological Society of North America Editors: Justin D Pearlman, MD, ME, PhD, MA, Director of Dartmouth Advanced Imaging Center, Professor of Medicine, Professor of Radiology, Adjunct Professor, Thayer Bioengineering and Computer Science, Dartmouth-Hitchcock Medical Center; Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand; Robert M Steiner, MD, Professor of Radiology, Temple University School of Medicine, Clinical Professor of Radiology, Medical School of the University of Pennsylvania; Consulting Radiologist, Temple University Hospital, Temple University Children's Medical Center; Robert M Krasny, MD, Consulting Staff, Department of Radiology, The Angeles Clinic and Research Institute; Eugene C Lin, MD, Consulting Staff, Department of Radiology, Virginia Mason Medical Center Author and Editor Disclosure Synonyms and related keywords: CP, constriction of the cardiac chambers, pericardium, thickened pericardium, pericardial thickening, stiffened pericardium, pericardial stiffening INTRODUCTIONSection 2 of 12
  BackgroundConstrictive pericarditis (CP) is a reduction in the elasticity, or stiffening, of the pericardium, a sack-like covering that surrounds the heart, resulting in impaired filling of the heart with blood. The symptoms of CP, which may include exercise intolerance, liver failure, dyspnea, and renal failure, appear insidiously (see Clinical Details) and may be misleading. Patients respond dramatically to a complete surgical pericardiectomy when it is performed early in the disease process; therefore, it is important to consider CP when making the diagnosis. Anatomic imaging findings, such as calcifications and thickening of the pericardium, may be present, but the most reliable and most important findings are related to the filling pattern of the heart. The severity of the clinical symptoms is best correlated with findings from dynamic observation of the blood flow and from findings relative to the obstruction and poor filling of the right-sided cardiac chambers. Various imaging methods (echocardiography, magnetic resonance imaging [MRI], computed tomography [CT]) can depict changes in cardiac chamber volumes throughout the cardiac cycle, as well as the timing of fluid motion backward into veins and forward into arteries. Both restrictive and constrictive diseases exhibit an abrupt reduction in filling, increased back pressure, and impaired stroke volume (volume of fluid ejected per heartbeat). Catheterization can be used to observe the pressure levels in various chambers during filling. The influence of respiration on filling contributes important diagnostic information, both for imaging and for catheterization. In CP, the size of the heart is usually normal; flattening of the right ventricle and curving of the intraventricular septum to the left are sometimes found. The azygos vein and superior vena cava (SVC) are commonly dilated. Restrictive disease (stiff muscle), such as that in dialysis patients with chronic amyloidosis, mimics the physiologic pattern of constrictive disease (stiff muscle). Amyloidosis does not cause constrictive pericarditis, but it can cause a restrictive cardiomyopathy that can mimic the clinical, imaging, and physiologic alterations of constrictive pericarditis. Symptoms of amyloidosis do not respond to pericardiectomy. Cardiac tamponade, a condition in which fluid accumulates in the pericardial space, is also in the differential diagnosis of impaired filling; however, it is usually not difficult to distinguish tamponade from restrictive or constrictive disease on images. Echocardiographic findings can also suggest CP. Duplex Doppler waveforms and inflow velocities across the mitral and tricuspid valves can be assessed during inspiration and expiration. This assessment is not part of the routine protocol in most echocardiography laboratories, and unless the physician is alerted to the possibility of CP, the diagnosis is almost never suspected. Dynamic respiratory criteria can also be applied during right- and left-sided heart catheterization when equalization of end-diastolic pressures in the heart chambers and characteristic venous waveforms are present. PathophysiologyRelevant anatomy and physiology CP consists of a stiffened and usually thickened pericardium caused by the activation of fibrocytic deposition of collagen. The space between the layers of the pericardium may get obliterated or divided into localized pockets. Calcification may further contribute to stiffness of the pericardium. A stiffened pericardium leads to elevation and equalization of filling pressures and pulmonary wedge pressure. Elevated venous pressure results in rapid early filling, which is curtailed abruptly by the nonexpandable pericardium. This is known as a dip-and-plateau pattern, a finding that is sensitive for constrictive pericarditis but is not specific to it. It also occurs in restrictive cardiomyopathy and, sometimes, in severe chronic obstructive pulmonary disease (COPD). Neck veins show a prominent Y descent, and the X descent may also be prominent (W pulsation pattern). This is distinct from findings in cardiac tamponade, which compresses the cardiac chambers throughout diastole, blunting the Y descent. The stiffened pericardium shields the chambers from changes in intrathoracic pressure; therefore, the normal decrease in return during inspiration is not observed and, instead, may increase (Kussmaul sign). Symptoms occur as a result of elevated venous pressure (ascites, edema), pulmonary congestion (dyspnea), and reduced cardiac output (fatigue, hypotension, tachycardia). In healthy patients, as well as in those with systolic dysfunction, the normal compliance of the pericardium allows for the transmission of intrathoracic pressures across the pericardium. During inspiration, left atrial pressure decreases because of a decrease in intrathoracic pressure. The normal compliance of the pericardium also causes the left ventricular diastolic pressure to decrease; ventricular filling is unchanged throughout the respiratory cycle. In CP, the pericardium is rigid and does not transmit intrathoracic pressure changes to the cardiac chambers. During inspiration, left ventricular diastolic pressure does not change, and left ventricular filling is impaired. The right ventricle can fill more during inspiration because the pericardial volume is fixed and left ventricular filling is impaired. The opposite physiologic process occurs during expiration, with improved left ventricular filling, greater Doppler velocities across the mitral valve, poor filling of the right ventricle, and lower Doppler velocities across the tricuspid valve. In patients with CP, the pericardium is usually thickened and is always rigid and noncompliant. Etiologies Although the etiology of pericardial thickening is unknown in many cases, viral or other infection or inflammatory processes are often implicated. Etiologies include the following:
FrequencyUnited StatesThere are no reliable figures for the prevalence and incidence of CP in the InternationalThere are no reliable figures for the prevalence and incidence of CP worldwide. Diagnosable infections, such as tuberculosis and parasitic disease (eg, echinococcal infection), are more likely causes of CP outside the Mortality/Morbidity
RaceCP does not appear to have any racial predisposition. SexMost surgically proved CP series report a male-to-female ratio of about 2:1; however, these series have included only a small number of patients. AgeCP can occur in individuals of any age, but it is rare in children. The mean age of adult patients with CP at diagnosis appears to be increasing. AnatomyThe pericardium is a fibroserous membrane that consists of an external fibrous layer, which is stout and dense, and an inner serous layer, which invests the heart and is reflected on the inner surface of the pericardium. Thus, the inner serous layer has a visceral component and a parietal component, which give the pericardium a friction-free surface that allows myocardial contraction and filling. The normal pericardium is 1 mm thick on CT scans or MRIs; thickening greater than 3 mm is abnormal. Clinical DetailsThe symptoms of CP appear insidiously, with patients displaying peripheral edema, anasarca, and elevated right-sided heart pressures. Patients frequently present with symptoms that are not thought to be due to cardiac disease; these include exercise intolerance, dyspnea, liver failure, and renal failure. The diagnosis is rarely considered by the referring physician, who usually may think that the symptoms are due to another disease process. Patients may present with increasing weight gain, cardiac cirrhosis, and massive ascites. The physician is most likely to refer patients with these symptoms to the radiologist for abdominal ultrasonography, abdominal and pelvic CT, or hepatobiliary scanning, thinking that the patient's symptoms are related to a liver disorder. CP responds dramatically to complete surgical pericardiectomy when it is performed early in the disease process; therefore, it is important to consider CP when making the diagnosis. Preferred ExaminationIn the minority of patients in whom the diagnosis of CP is suspected on a clinical basis, the first test should be plain posteroanterior (PA) and lateral chest radiography. If the results show characteristic pericardial calcification, the diagnosis of CP is essentially established. As many as 50% of patients with CP have pericardial calcification. The classic and most common distribution is largely over the right ventricle; this appearance can be considered pathognomonic. If the plain radiographic findings are negative and clinical suspicion of CP is present, echocardiography with an evaluation of Doppler inflow velocities of the mitral and tricuspid valves during inspiration and expiration should be performed. Ventricular interdependence is present in all patients with significant constrictive physiologies. No imaging test is definitive for the diagnosis of CP in all patients who have the disease. In a patient in whom the clinical findings are suggestive of the disease, noninvasive imaging findings that are consistent with CP are usually sufficient to prompt definitive surgery or an invasive evaluation in the catheterization laboratory. The diagnosis of CP is more difficult in patients without calcification. Pericardial thickening of 4 mm or more on CT scans or MRIs is considered evidence of CP for patients with the appropriate symptoms; however, focal thickening of 4 mm or more commonly occurs in patients without physiologic or clinical evidence of constrictive physiology. The converse is also true. Rarely, a constrictive physiology can be present without abnormal thickening of the pericardium. Limitations of TechniquesAll of the noninvasive imaging techniques have limitations in the diagnosis of CP. Ultimately, the diagnosis is made at surgery; however, in the appropriate patient, CT, ultrasonography, conventional radiography, MRI, echocardiography, and right- and left-sided heart catheterization results can be highly suggestive of CP. A major problem is differentiating restrictive cardiomyopathy from CP. Furthermore, it is difficult to preoperatively predict which patients are likely to respond to total pericardiectomy. DIFFERENTIALSSection 3 of 12
Budd-Chiari Syndrome Carcinoid, Gastrointestinal Cardiomyopathy, Hypertrophic Cardiomyopathy, Restrictive Cirrhosis Congestive Heart Failure Ebstein Anomaly Hemochromatosis Tricuspid Atresia Tricuspid Valve Disease Other Problems to Be ConsideredDavies disease
RADIOGRAPHSection 4 of 12
FindingsPlain chest radiographs may show pericardial calcification in as many as 50% of CP patients, although anecdotal evidence suggests that this number is decreasing. The cardiac silhouette should be small in a patient with uncomplicated CP. CP can also coexist with cardiomyopathy, and a large heart does not exclude the disease. Other, less reliable plain radiographic findings include an abnormal cardiac contour, such as straightening of the right atrial border and, more rarely, straightening of the right and left cardiac borders, with obliteration of the normal curves, on frontal images. On fluoroscopy, diminished cardiac pulsation may be seen. Degree of ConfidenceIn a patient with diffuse pericardial calcification on radiographs and appropriate clinical symptoms of constrictive physiology, the diagnosis of CP can be reliably made. The absence of calcification does not exclude the disease, and further testing should include an extensive workup in the echocardiography laboratory, with an assessment of the Doppler velocities across the mitral and tricuspid valves during inspiration and expiration. Because complete surgical pericardiectomy is usually effective (but not without a risk of morbidity and mortality), most patients also undergo simultaneous right- and left-sided heart catheterization, with a measurement of various pressures during inspiration and expiration. False Positives/NegativesIf the radiograph is positive for pericardial calcifications and the patient's symptoms are consistent with CP, false-positive findings should not occur. The diagnosis is difficult to make in patients with CP but without pericardial calcifications. In these patients, normal findings on plain radiographs are false negatives. CT SCANSection 5 of 12
FindingsThe pericardium should be diffusely thicker than 3 mm; however, many patients do not present with this finding, and the diagnosis of CP should not be discarded if thickening is not present. The size of all 4 heart chambers should be within the normal range; however, CP can coexist with other diseases, and global or focal dilatation of the cardiac chambers does not exclude CP. The inflow veins to the right atrium, including the SVC, inferior vena cava (IVC), and hepatic veins, should be dilated. This finding is necessary but not sufficient to make the diagnosis of CP because it commonly occurs in the setting of congestive heart failure brought on by a variety of causes. Most often, when the hepatic veins and IVC are dilated for reasons other than CP, dilatation of 1 or all of the cardiac chambers is present and caused by systolic dysfunction or valve disease. If significant cirrhosis has already occurred, the hepatic veins may not be dilated. There should be no progression of the contrast-agent bolus through the vascular system, and evidence of significant systolic dysfunction should be absent. For example, if the injection protocol involves a 60-second delay from the time of the injection to the start of scanning, contrast enhancement in the portal veins and waning of that enhancement in the abdominal aorta are usually seen. In CP, there should be poor opacification of liver parenchyma due to congestion and there should be no contrast enhancement in the portal vein.Degree of ConfidenceIn the appropriate patient, CT findings can be highly suggestive of CP; however, because the preferred treatment is total pericardiectomy, which has significant morbidity and mortality risks, almost all patients should be referred for cardiac echocardiography and/or simultaneous right- and left-sided heart catheterization. False Positives/NegativesMany of the CT findings of CP can also be found in patients with other diseases and in some asymptomatic conditions. Focal or diffuse thickening of the pericardium can occur in the absence of constrictive physiology. An apparently delayed bolus of contrast material can be caused by technical factors in the acquisition of the CT scan. Dilated veins can be caused by right-sided heart failure. Liver cirrhosis can mimic the CT findings of CP. MRISection 6 of 12
FindingsDiffuse thickening of the pericardium greater than 3 mm can be observed on multiplanar MRIs. ECG-triggered MRI is sensitive to constrictive disease of the pericardium because the fibrous layers are bordered by fat, which produces a distinct MRI signal. MRI can be used to measure pericardial thickness; the ideal views for measuring pericardial thickness are oriented perpendicular to the long axis of the left ventricle. MRI can also be used to measure chamber sizes at successive 50-msec delays after the R wave and to determine whether or not a filling plateau is present. Like echocardiography and/or Doppler imaging, velocity-encoded (VENC) MRI can be used to assess volumetric flow and regurgitant flow to the pulmonary veins and the hepatic vein. MRI can demonstrate focal abnormalities and can cover the heart to determine whether the disease encapsulates its entirety. MRI dynamically shows a reversed curvature of the intraventricular septum clearly. Degree of ConfidenceMRI does not depict pericardial calcifications, but otherwise, MRI is highly sensitive and specific. The main limitation with MRI is the greater cost relative to echocardiography. Furthermore, most patients with CP who are referred for imaging are not suspected of having the disease; therefore, MRI is rarely ordered to rule out CP. False Positives/NegativesA patient may have focal or even diffuse thickening on MRIs without a constrictive physiology. Conversely, a patient may have a constrictive physiology with subtle, diffuse thickening of the pericardium of less than 3 mm (which is the upper limit of the normal range); however, the physiologic alteration created by CP can be evaluated by performing VENC MRI of the pulmonary and hepatic veins and velocities across the mitral and tricuspid valves. This technique is usually reliable in detecting constrictive physiology. ULTRASOUNDSection 7 of 12
FindingsLiver sonograms show dilated hepatic veins and abnormal pulse Doppler waveforms in the portal and hepatic veins due to outflow obstruction. Cardiac echograms show normal contraction and systolic function. Special procedures, including an assessment of Doppler velocities across the mitral and tricuspid valves during inspiration and expiration, are needed to demonstrate ventricular interdependence. Unless the staff in the echocardiography laboratory is alerted to the clinical suspicion of CP, the diagnosis is often not considered and, therefore, is missed. Newer echocardiographic procedures, such as the evaluation of the early diastolic Doppler myocardial velocity gradients at the posterior wall, tissue Doppler echocardiography, and color M mode flow propagation, have recently been reported to enhance the differentiation between CP and restrictive cardiomyopathy. Degree of ConfidenceAbdominal ultrasonographic findings are nonspecific and must be confirmed with echocardiography and cardiac catheterization results. False Positives/NegativesBudd-Chiari syndrome, cirrhosis, and right-sided heart failure can mimic some of the findings of CP at liver ultrasonography. NUCLEAR MEDICINESection 8 of 12
FindingsBecause of liver function abnormalities caused by hepatic congestion, hepatobiliary scanning is often ordered for patients in whom CP is not suspected. The hepatobiliary scan findings are impaired hepatic clearance of the agent from the blood pool and severely impaired excretion of the radiopharmaceutical agent into the biliary tree. Gated nuclear ventriculography may show rapid ventricular filling in CP. Reportedly, these findings can be used to differentiate CP from restrictive cardiomyopathy. Degree of ConfidenceMany conditions that are more common than CP can impair hepatic uptake and excretion of the radiopharmaceutical agent. If the physician is perceptive enough to consider the diagnosis of CP, the diagnosis must be confirmed with echocardiography and heart catheterization. False Positives/NegativesHepatitis, drug-induced cholestatic liver disease, severe cirrhosis, and severe right-sided heart failure can cause findings similar to those of CP. ANGIOGRAPHYSection 9 of 12
FindingsAngiography usually has no role in the evaluation of CP. Simultaneous right- and left-sided heart catheterization and measurement of cardiac chamber pressures during inspiration and expiration are the most useful confirmatory tests. Degree of ConfidenceMeasurements obtained in the catheterization laboratory can be highly suggestive of CP. Although considered the criterion standards, the traditional hemodynamic criteria used in the catheterization laboratory for the diagnosis of CP are neither sensitive nor specific, and they significantly overlap with those of restrictive diseases that can also alter the diastolic filling properties. The criteria are the following:
Significant information can also be gained from echocardiography. Ultimately, the diagnosis must be confirmed surgically at the time of complete pericardiectomy. Only 50% of patients respond to surgery, but in many patients, the symptoms dramatically resolve. False Positives/NegativesRestrictive heart disease can mimic some manifestations of CP at catheterization or echocardiography. INTERVENTIONSection 10 of 12
No percutaneous interventions are used to treat CP. The condition requires surgical pericardiectomy. Medical/Legal Pitfalls
MULTIMEDIASection 11 of 12
REFERENCESSection 12 of 12
Constrictive Pericarditis excerpt Article Last Updated: Jul 24, 2007 | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
