Myxedema

The decision to undergo pericardectomy for symptomatic pericardial constriction is usually dictated by an image of an abnormal pericardium. We report a case of symptomatic pericardial constriction despite radiographie and pathological evidence of a normal pericardium. The patient was successfully treated with a pericardectomy, with resolution of constrictive hemodynarnics and symptoms. Our report suggests that a normal pericardium by computed tomography and biopsy should not preclude pericardectomy for patients who have refractory symptoms, physical findings, and intracardiac pressures diagnostic of constrictive pericarditis.

Introduction

Constrictive pericarditis is a disorder of the pericardium that limits early diastolic filling of the ventricles. This limitation results in progressive symptoms of venous congestion, including malaise, dyspnea, orthopnea, and lower extremity edema.12 In developed countries, constrictive pericarditis is typically idiopathic, although other etiologies, such as surgery, radiation, infection, drugs, connective tissue disorders, myocardial infarction, renal failure, myxedema, and sarcoidosis, have been reported.1 Tuberculosis had been the leading cause of constrictive pericarditis worldwide but is now rare because of the advent of appropriate antitubercular therapy.3,4

The diagnosis of constrictive pericarditis can be elusive, and the disorder may mimic other disorders, such as restrictive cardiomyopathy, cor pulmonale, tricuspid stenosis, and congestive heart failure.1,4,5 Constrictive pericarditis can be particularly difficult to differentiate from restrictive cardiomyopathy. Diagnostic tests include measurement of intracardiac pressures, pericardial imaging, and pericardial biopsy.5 Most patients with constrictive pericarditis have excellent functional improvement with pericardectomy, although this procedure is associated with a 4 to 18% early mortality rate.6

We describe a patient with symptomatic pericardial constriction diagnosed on the basis of classic symptoms, physical findings, and hemodynamic abnormalities with cardiac catheterization. This patient had a normal pericardium by chest computed tomography (CT). The patient had complete resolution of symptoms and physical examination findings after removal of her grossly and microscopically normal pericardium. We found no previous reports of resolution of constrictive pericardial symptoms with removal of a normal pericardium in the literature.

Case Report

A 67-year-old female patient with a history of hypertension and type 2 diabetes mellitus presented with gradual onset of lower extremity edema, dyspnea on exertion, fatigue, and malaise. She denied chest pain, orthopnea, recent illness, travel, or a positive purified protein derivative test result. Her medications included atenolol, quinapril, hydrochlorothiazide, aspirin, rosiglitazone, glyburide, and estrogen.

Physical examination revealed an afebrile, hypertensive, female patient with bibasilar lung crackles, bilateral lower extremity pitting edema, and jugular venous distension (7 cm). She did not demonstrate Kussmaul's sign. Her electrocardiogram showed sinus bradycardia, first-degree atrioventricular block, and a wide notched P-wave. The echocardiogram demonstrated biatrial enlargement, moderate tricuspid and mild mitral regurgitation, mild pulmonary hypertension (pulmonary artery systolic pressure of 35 mm Hg), rapid early diastolic filling, and normal right and left ventricular size and function. There was no diastolic dysfunction, pericardial thickening, or effusion. Respiratory variation was not assessed.

Right heart catheterization revealed elevated right atrial and pulmonary capillary wedge pressures and equalization of right ventricular, pulmonary artery, and left ventricular diastolic pressures (Table I), with a prominent Y-descent; a square root sign was also seen in the right ventricular pressure tracing (Fig. 1A). Contrast chest CT scan, obtained approximately 1 week later, demonstrated a normal pericardium (Fig. 2).

The patient continued to have symptoms despite medical management with diuresis and afterload reduction. Two weeks later, she was referred for surgery and underwent a pericardectomy with the lower median sternotomy approach. Although there was a moderate amount of clear fluid in the pericardial space, the pericardium was grossly normal, without thickening or adhesions between the epicardium and pericardium. Microscopic evaluation noted no malignancy or other histopathological abnormality, with a thickness of 1 mm (Fig. 3).

After surgery, the patient had complete resolution of her symptoms, lung crackles, jugular venous distention (

The patient continues to be free of symptoms and abnormal examination findings 3 years after surgery. A follow-up echocardiogram several years after her surgery continued to reveal normal left ventricular size and function, with no additional findings to suggest a diagnosis of restrictive cardiomyopathy.

The diagnosis of constrictive pericarditis can be difficult, because the characteristics often run parallel to those of restrictive cardiomyopathy. Measurement of intracardiac pressures, pericardial imaging, and biopsy are typically used to make the diagnosis.5 It is important to make this differentiation, because constrictive pericarditis can be cured with pericardectomy and restrictive cardiomyopathy should not improve with this procedure. The decision to undergo pericardectomy for symptomatic pericardial constriction is usually dictated by an image of an abnormal pericardium.

Various hemodynamic, imaging, and pathological findings have been proposed to differentiate constriction from restriction.3,5,7 Because of the many limitations often cited for hemodynamic criteria,5 the use of imaging is considered to be the standard method for diagnosis, short of a pericardial biopsy. CT studies are considered very accurate in diagnosing constrictive pericarditis, and some think a negative CT examination virtually excludes the diagnosis.3,8,9 Two studies reported 100% diagnostic accuracy of CT scans in differentiating constriction from restriction,8,9 albeit with a limited number of patients. CT images, however, fail to diagnose symptomatic pericardial constriction when pericardial thickening is absent. Indeed, 4% of patients with constrictive pericarditis were found to have a normal-thickness pericardium in a surgical pathology case series.10 Pericardectomy has been shown to be very successful in relieving symptoms of constrictive pericarditis.1 Most patients with constrictive pericarditis have excellent functional improvement after pericardectomy,11 although this procedure is associated with a 4 to 18% early mortality rate.3 Because of the significant morbidity and mortality rates associated with this procedure, many are reluctant to proceed to pericardectomy without conclusive imaging data.

Our patient had initial right heart catheterization findings classic for constrictive pericarditis but normal CT findings. Furthermore, results of gross and microscopic examinations of the pericardium were normal. Nevertheless, removal of this structurally normal pericardium resulted in resolution of symptoms, physical findings, and constrictive hemodynamics.

The cause of the patient's constrictive symptoms and hemodynamics despite a normal pericardium is unknown. Diagnostic possibilities include but are not limited to sampling error with biopsy (inflammation present but missed), physiological constriction (limiting the size and/or compliance of the pericardium), or preceding inflammation that resolved before surgery.

Persistent elevated right atrial pressures were noted on the repeat catheterization that were not evident on the initial catheterization, which may suggest that the patient suffered from a combination of restrictive cardiomyopathy and constrictive pericarditis (a form of physiological constriction), the latter being cured with pericardectomy. The resolution of symptoms and findings that has continued for several years after the operation is not consistent with the progressive course (e.g., poor prognosis) seen with restrictive cardiomyopathy.

The accepted approach to the diagnosis of a diseased pericardium is through imaging and measurements of intracardiac pressures.4 We report a case of pericardial constriction in a patient with normal CT scans as well as normal gross and microscopic pericardial findings. Our case report suggests that, when hemodynamic findings are diagnostic, pericardial constriction may exist despite normal pericardial imaging and even normal histological findings. These patients, if symptomatic, should be considered for a pericardectomy.

Acknowledgment

We acknowledge Ramakota Reddy, MD.

References

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3. Suchet I, Horwitz T: CT in tuberculous constrictive pericarditis. J Comp Asst Tomgr 1992; 16: 391-400.

4. Braunwald E: Pericardial disease. In: Harrison's Principles of Internal Medicine, Ed 14, pp 1334-41. Edited by Fauci A, Braunwald E, Isselbacker K, et al. New York, McGraw-Hill, 1998.

5. Vaitkus P, Kussmaul W: Constrictive pericarditis versus restrictive cardiomyopathy: a reappraisal and update of diagnostic criteria. Am Heart J 1991; 122: 1431-41.

6. Astudillo R, Ivert T: Late results after pericardectomy for constrictive pericarditis via left thoracotomy. Scand J Thorac Cardiovasc Surg 1989; 23: 115-9.

7. Hurrell D, Nishimura R, Higano S, et al: Value of dynamic respiratory changes in left and right ventricular pressures for the diagnosis of constrictive pericarditis. Circulation 1996; 93: 2007-13.

8. Button F, Whitley N, Applefield M: The role of echocardiography and CT in the evaluation of constrictive pericarditis. Am Heart J 1985; 109: 350-5.

9. Isner J, Carter B, Bankoff M, et al: Differentiation of constrictive pericarditis from restrictive cardiomyopathy by computed tomographic imaging. Am Heart J 1983; 105: 1019-25.

10. Oh KY, Shimizu M, Edwards WD, Tazelaar HD, Danielson GK: Surgical pathology of the parietal pericardium: a study of 344 cases (1993-1999). Cardiovasc Pathol 2001; 10: 157-68.

11. Trotter M, Chung K, Ochsner J, McFadden P: Pericardectomy for pericardial constriction. Am Surg 1996; 62: 304-7.

Guarantor: Maj Steven J. Burning, USAF MC

Contributors; Capt Kevin Steel, USAF MC*; Maj Steven J. Durning, USAF MC[dagger]; Capt Chad DeMott, USAF MC*; Mark Haigney, MD[double dagger]

* Department of Internal Medicine, Wright-Patterson Medical Center, WrightPatterson Air Force Base, OH 45433-5529.

[dagger] Department of Internal Medicine, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.

[double dagger] Department of Cardiology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814.

Presented at meetings of the Ohio American College of Physicians-American Society of Internal Medicine, October 12, 2001, Cleveland. OH, and the Society of Air Force Physicians, February 26, 2001, San Antonio, TX.

This manuscript was received for review in December 2003. The revised manuscript was accepted for publication in August 2004.

Copyright Association of Military Surgeons of the United States Aug 2005
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