Cardiac compression occurs in chronic constrictive pericarditis. But cardiac compression is also a feature of acute cardiac tamponade and effusive constrictive pericardial disease—a condition characterized by fluid in the pericardial space and markedly reduced compliance of the pericardium.

Chronic constrictive pericarditis.

The basic pathophysiology of chronic constrictive pericarditis has been debated for over half a century. By 1949, Holman and Willett concluded that constriction of the caval orifices and atria was important in its pathogenesis. For this reason, they adopted the median sternotomy approach for its surgical correction. In 1951, Burwell concluded from cardiac catheterization study that both right and left ventricular function were impaired, and constriction of caval orifices or atria played no role. In 1952, Isaacs and colleagues showed in dogs that a change in the pressure-volume curves of the two ventricles resulted from experimentally produced constrictive pericarditis, which was the fundamental pathophysiologic change associated with the disease ( Fig. 18.1 ). These investigators also demonstrated, during the development of constriction, an increase in right and left ventricular diastolic pressure and a decrease in stroke volume. In their experimental animals, a small increase in volume resulted in a considerable increase in end-diastolic pressure. These studies indicated that lack of ventricular diastolic distensibility, and thus inability to generate an adequate preload (see Chapter 4 ), was a characteristic of hearts with chronic constrictive pericarditis. These considerations influenced Scannell and colleagues to adopt a left anterolateral thoracotomy as their surgical approach of choice by 1952.

Pressure-volume curves of left and right ventricles (LV, RV) in dogs, made immediately after death by introducing 10-mL boluses of saline solution via aorta or pulmonary artery into the closed ventricle. Note that in the normal dog heart (Before), compliance of right ventricle is greater than left. In hearts of dogs with generalized pericardial constriction (After), compliance is low and similar in both ventricles.

(Data from Isaacs JP, Carter BN 2nd, Haller JA Jr. Experimental pericarditis: the pathologic physiology of constrictive pericarditis. Bull Johns Hopkins Hosp . 1952; 90:259.)

Several features of clinical cases of chronic constrictive pericarditis derive from these basic abnormalities of diastolic function. Ventricular filling is impaired, and ventricular stroke volume is reduced because of decreased compliance of the fused cardiac and pericardial mass. Phasic aspects of ventricular filling are also altered. For a brief period in early diastole, ventricular filling is rapid. However, the limit of ventricular distensibility is reached rapidly, and the right ventricular pressure pulse displays an early diastolic dip and then a high diastolic plateau (square root sign) . There is nearly complete diastolic ventricular filling during the first 50 milliseconds of diastole.

Systemic venous pressures are correspondingly abnormal; mean venous pressure is elevated. The x descent is steep and deep, corresponding to the beginning of ejection. The y descent is also steep and deep, corresponding to the early diastolic dip of right ventricular pressure. This differs from events during acute cardiac tamponade, where the y descent is absent. The normal inspiratory increase in vena caval flow and decrease in pressure are diminished and often absent.

Pulsus paradoxus is said to be infrequent in chronic constrictive pericarditis, in contrast to the situation with acute cardiac tamponade. However, the frequency of its recognition is influenced by cardiac rhythm; it is usually present when there is sinus rhythm but impossible to detect when there is atrial fibrillation (a frequent accompaniment of chronic constrictive pericarditis).

Ventricular end-diastolic volumes are small in this disease, as are end-systolic volumes and stroke index. The rate of increase of left ventricular systolic pressure and ejection fraction is not altered. Thus, systolic left ventricular function under these circumstances is normal, but this does not necessarily indicate normal contractility.

In most patients the etiology of chronic constrictive pericarditis is not known. McCaughan and colleagues were able to identify a specific etiologic factor in only 27% of their patients and Blake and colleagues in only 34%. ^, In the current era (>1990), nearly half of cases have a nonidiopathic etiology (postoperative 32.3%, radiation 11.4%). In about 10% of cases, documented acute pericarditis precedes the development of chronic constrictive pericarditis. Prior to its effective treatment, tuberculosis was the etiology of chronic constrictive pericarditis in up to 17% of cases. ^, Currently, a prominent cause is mediastinal radiation for malignant disease. Rheumatoid disease and sarcoidosis occasionally are causes. Trauma is another uncommon cause, with hemopericardium usually present as the precursor of pericardial thickening and constriction. ^,

Prior cardiac surgery is an increasingly common cause of constrictive pericarditis, and it may be more common after coronary artery bypass grafting than after other operations. The interval between the original cardiac operation and the development of evidence of pericardial constriction is highly variable, ranging from 1 month to nearly 10 years. Mean interval is about 2 years.

Classically, symptoms of chronic constrictive pericarditis are delayed for several years after the clinical or subclinical episode of acute pericarditis. The interval may, however, be as short as 3 to 4 weeks in those rare instances in which pericarditis develops after cardiac surgery or 4 to 12 months after trauma or acute nonspecific pericarditis.

Initial symptoms may be only fatigue with or without modest effort breathlessness, and neck vein distention may be noticed. Insidiously, however, hepatomegaly and ascites develop, initially with or without peripheral edema. Even within the context of such evidence of appreciable fluid retention, breathlessness may occur only on exertion and not at rest; although in severe cases, there may be orthopnea. Paroxysmal nocturnal dyspnea occurs infrequently.

When constriction is not severe, clinical findings may be limited to modest but persistent elevation of jugular venous pressure and slight liver enlargement with or without intermittent ankle edema. As constriction increases, there is a progressive increase in venous pressure and hepatomegaly, with the eventual development of persistent peripheral edema, ascites, and pleural effusion. Venous pressure fails to decline during inspiration (Kussmaul sign), but this is not specific, in that the same findings may accompany right ventricular failure, restrictive myocardial disease, or tricuspid valve stenosis. By this stage, pulsus paradoxus is to be expected if sinus rhythm persists, and pulse pressure often is reduced. The apex beat is usually not palpable, but there is often systolic retraction in the left parasternal region. This retraction may be followed by a visible and palpable forward thrust extending toward the expected site of the cardiac apex. This impulse, which results from forceful ventricular filling with the onset of diastole, may be mistaken for the apex beat and used to argue against the existence of pericardial constriction. Rapid ventricular filling in early diastole is also associated with an unusually early, often loud, third heart sound that is sometimes referred to as a pericardial knock, but usually, there are no murmurs.

As in other forms of heart failure, salt and water retention are present. Anand and colleagues found important increases in total body water, extracellular volume, plasma volume, and exchangeable sodium in their study of patients with proven constrictive pericarditis. However, renal plasma flow was only moderately decreased, and glomerular filtration rate was normal. Norepinephrine, renin activity, aldosterone, and cortisol were also increased, as was plasma atrial natriuretic hormone, although not to levels usually seen in other heart failure syndromes. The ratio of left atrial to aortic diameter measured by echocardiography was only minimally increased, indicating that in constrictive pericarditis, the atria are prevented from expanding. The restricted distensibility of the atria may limit the secretion of atrial natriuretic hormone, thus reducing natriuretic and diuretic effects, resulting in retention of sodium and water greater than that occurring in patients with edema from myocardial disease.

Protein-losing enteropathy occurs in some patients with chronic constrictive pericarditis who develop ascites and hepatomegaly. They may have severe hypoproteinemia, with depression of albumin and gamma globulin, and an increased rate of leakage of plasma protein into the gastrointestinal tract. This syndrome also develops after other conditions that chronically elevate inferior or superior vena caval pressure, such as the Fontan operation and atrial switch operations with inferior vena caval obstruction (see Chapter 52 ). The preoperative model for end-stage liver disease (MELD) and MELD-XI score provides important morbidity and mortality risk stratification in constrictive pericarditis patients.

The chest radiograph may be unremarkable, although about one-third of patients show moderate to marked enlargement of the cardiac silhouette, and some have pleural effusions. Pericardial calcification is evident in about 25% and radiologic evidence of compression in about 60%.

The electrocardiogram (ECG) is usually abnormal, with nonspecific ST-segment and T-wave changes in 90% of cases. In about 40% of patients with surgically verified chronic constrictive pericarditis, the QRS complexes have low voltage, and an atrial arrhythmia is present in 30%.

Characteristically, end-diastolic pressures are elevated and equal in the right atrium, pulmonary artery, and left atrium; this is the hallmark of chronic constrictive pericardial disease. ^, In the report by McCaughan and colleagues, such findings were obtained in all patients coming to catheterization. Intraventricular pressure pulse contours characteristically demonstrate an early rapid fall in diastolic pressure in the right ventricle, followed by a rapid rise to an elevated diastolic plateau (square root sign). ^, Left ventricular pressure pulse usually has a similar contour.

Mean right atrial pressure fails to decrease normally during inspiration, or it may rise slightly. There is a transient increase in pulmonary blood volume and a slight reduction in right ventricular afterload, resulting in a fall in pulmonary arterial and right ventricular systolic pressure and a decline in pulmonary venous pressure and left ventricular diastolic pressure as well.

Vaitkus and Kussmaul identified the predictive accuracy of three different hemodynamic criteria for differentiating constrictive from restrictive disease ( Table 18.1 ): (1) equalization of right and left ventricular end-diastolic pressure favors constriction; (2) constriction is associated with more modest elevation of right ventricular systolic pressure (≤50 mmHg); in restriction, it exceeds that amount; (3) in constriction, right and left ventricular end-diastolic pressure usually are greater than one-third of right ventricular systolic pressure; in restriction, the ratio is characteristically less than one-third.

The Mayo Clinic group has further identified two dynamic criteria that greatly aid in the diagnosis of constrictive pericarditis. ^{, ,} The first is dissociation of intrathoracic and intracardiac pressures during inspiration with a significant decrease in the gradient between the pulmonary artery wedge pressure and left ventricular diastolic pressure. The second is ventricular interdependence with discordance between right and left ventricular tracings during inspiration. Enhanced ventricular interaction can also be assessed with the comparison of ejection times in the pulmonary artery and ascending aorta. This technique simplifies the assessment for constriction and differentiating constriction from restrictive cardiomyopathy and severe tricuspid valve regurgitation.

When hemodynamic studies are equivocal, rapid infusion (in 6 to 8 minutes) of 1000 mL of normal saline solution produces diagnostic features of occult chronic constrictive pericardial disease. ^, These features include not only striking elevations of filling pressures but also development of typical pressure pulse morphologic characteristics of constriction, loss or reversal of the respiratory variation of right atrial pressure, and precise diastolic equilibration of cardiac pressures.

When diagnosis is unclear, myocardial biopsy may be useful. Normal myocardium, nonspecific changes (e.g., from irradiation), or myocarditis on biopsy must be considered nondiagnostic, because they may be present with either restrictive or constrictive disease. The finding of amyloid disease is diagnostic of a restrictive etiology.

Knowledge of the natural history of surgically untreated patients with chronic constrictive pericarditis is incomplete. The interval between an etiologic event and onset of clinical evidence of constriction varies between a few months and many years. Factors that determine rate of progression of the disease and its symptoms are unknown. Atrial fibrillation commonly occurs at some stage and can result in sudden deterioration in circulatory status.

Somerville has estimated that once signs and symptoms of chronic constrictive pericarditis develop, a semi-invalid life can be led over an interval of 5 to 15 more years. When the clinical syndrome includes ascites, progression is more rapid, particularly in children.

Because patients with chronic constrictive pericarditis coming to operation are often seriously ill, an arterial catheter is inserted into the radial artery for pressure recording, in addition to usual preparations in the operating room. A central venous pressure line and often a pulmonary arterial catheter are also inserted. Approach may be through a median sternotomy or left anterolateral thoracotomy.

The median sternotomy approach may be used with or without cardiopulmonary bypass (CPB). Although unnecessary for most patients, CPB facilitates dissection of the heart from the pericardium especially when there is calcification that burrows into the myocardium. Extracorporeal circulation is also useful for support when dissection and manipulation of the ventricles lead to hemodynamic disturbance. Perfusion is maintained at normothermia, and arrest of the heart is rarely necessary. When CPB is used, it may be convenient to use the femoral vessels for both venous and arterial cannulation (see Special Situations and Controversies of Chapter 2 ).

The pericardium is opened vertically anteriorly in the midline ( Fig. 18.2 ). Opening both pleural spaces facilitates exposure and identification of the phrenic nerves. The pericardial flaps are then dissected laterally with low voltage electrocautery, superiorly and inferiorly. To the right, dissection passes across the atrioventricular groove and proceeds across the anterior and lateral walls of the right atrium if the cleavage plane is easily developed. If it is not, as previously stated, this portion of thickened pericardium can be left in situ as constriction is a disease of the ventricles, and freeing the atria is not necessary. In the former instance, the pericardial flap is excised about 1 to 1.5 cm anterior to the right phrenic nerve. To the left, dissection proceeds across the front of the ventricles and then over the lateral left ventricular wall to about 1 to 1.5 cm in front of the left phrenic nerve.

Pericardiectomy for chronic constrictive pericarditis through a left anterolateral incision. (A) Positioning of patient and proposed incision. Padding beneath left arm is important. (B) Phrenic nerve has been mobilized away from pericardium. An initial longitudinal incision has been made in thickened parietal pericardium. (C) Flaps have been dissected back, completely liberating both left and right ventricles, leaving where necessary small calcific plaques in situ. First portion of pulmonary trunk has been completely unroofed. (D) Appearance at end of procedure. Thickened pericardium has been removed from diaphragm.

The anterior pericardium is excised from the great vessels to the diaphragm ( Fig. 18.3 ). Dissection continues over the diaphragm inferiorly and, when it can be safely performed, posterior to the left phrenic nerve back to the left atrioventricular groove ( Fig. 18.4 ). It is sometimes possible to remove the thickened, often calcified, outer pericardial layer, because there is generally a cleavage plane between pericardium and the overlying thickened pleura containing the phrenic nerve. Most often the phrenic nerve can be left attached to a strip of pericardium. The inferior pericardium can usually be separated easily from the underlying fibrous, central diaphragm ( Fig. 18.5 ). The coronary arteries should be visible on the surface of the heart. If the epicardium is thin and relatively normal, it need not be disturbed. If it is thickened, it must be removed either in its entirety or in a sufficient number of areas to allow more normal diastolic filling of the ventricles. ^, Failure to do this compromises results of operation.

The pericardium and the right and left phrenic nerves are shown through a median sternotomy exposure. The pericardium is incised near the midline.

(From Hemmati A. Contemporary techniques of pericardiectomy for pericardial disease. Cardiol Clin . 2017;35(4):559-566.)

After sharp dissection toward the left and right phrenic nerves, the anterior pericardium is removed, exposing the epicardial coronary arteries. The pericardium beneath each phrenic nerve is preserved to avoid injury.

(From Hemmati A. Contemporary techniques of pericardiectomy for pericardial disease. Cardiol Clin. 2017;35(4):559-566.)

The heart is freed from the diaphragmatic aspect of the pericardium and the pericardium posterior to the left phrenic nerve. The pericardium is then dissected from the diaphragm as shown.

(From Hemmati A. Contemporary techniques of pericardiectomy for pericardial disease. Cardiol Clin . 2017;35(4):559-566.)

The patient is positioned supine, with a roll beneath the left scapula. The left hand is secured beneath the left buttock, with the elbow padded and positioned on the left side of the table ( Fig. 18.2 A). A curving left anterolateral skin incision is made beneath the breast anteriorly and more laterally over the fifth interspace. Incision is carried through the pectoralis major anteriorly, and the fifth interspace is opened. The interspace incision is extended well anteriorly. The internal thoracic vessels can be ligated and divided. The incision can be taken across the sternum if exposure is inadequate. The rib spreader is inserted, and the interspace incision extended laterally with electrocautery as the spreader is gradually opened.

The left phrenic nerve is identified and freed from the pericardium if possible. Because the nerve is often densely adhered to the pericardium, most commonly the nerve can be mobilized with a narrow strip of pericardium to avoid injury. The pericardium is incised through an area of minimal calcification posterolateral, if possible, over what is presumed to be left ventricle ( Fig. 18.2 B). On occasion, this initial incision through the abnormal pericardium takes the dissection immediately onto the myocardium; in other cases, it enters a fluid-filled space (see “ Morphology ” earlier in this section).

When a space is entered, the initial longitudinal incision is carried anteriorly and posteriorly from its superior and inferior extremes. The anterior pericardial flap is dissected as far as the right atrioventricular groove, beneath the elevated thymus and prepericardial fat, and resected ( Fig. 18.2 C). The posterior flap is dissected far posteriorly to the level of the left atrioventricular groove and then excised. Dissection must be carried superiorly onto the pulmonary trunk, because failure to relieve pericardial bands across it can result in postoperative gradients and severe right ventricular hypertension. The piece of pericardium left inferiorly is dissected off the diaphragm. Fibrous plaques adherent to the epicardium are then dissected off through the entire area of resection.

If no pericardial space is found, the entire longitudinal incision and its anterior and posterior extensions are made only through the fibrous pericardium. Then the incision is deepened in an area that seems to be over myocardium rather than over the interventricular or atrioventricular groove. Slowly and carefully, the posterior flap is dissected off the left ventricular myocardium. At first, this dissection is done only in areas in which it proceeds reasonably well, leaving the epicardium on the myocardium wherever it is thin and normal. When dissection in this plane is not possible, such as in an area of calcification or dense scarring, islands of calcification and scarring may be left attached to the myocardium but separated from other areas. Dissection moves to the anterior pericardial flap whenever progress ceases posteriorly and vice versa. In the setting of constrictive pericarditis, it is not necessary to dissect across the interventricular groove containing the coronary vessels. But it is important to be certain that all constrictions on the atrioventricular groove are removed, because they can result in gradients between atrium and ventricle.

No special effort is made to free the atria, venae cavae, or cavoatrial junctions because constriction does not occur in these areas. When dissection is complete, the pericardial flaps, as well as the diaphragmatic portion of the pericardium, are excised ( Fig. 18.2 D).

Two pleural drainage catheters are inserted, the tip of one being placed posteriorly and inferiorly and that of the other anteriorly and superiorly. The interspace incision is closed with heavy pericostal and perichondrial absorbable sutures, and the muscle layers are closed with continuous absorbable sutures. The skin is closed with a continuous subcuticular suture.

The main advantage of median sternotomy is perceived improved ability to free the heart from the pericardium and remove pericardium from the right ventricle. ^, The main advantages of the left anterolateral approach are cosmetic, exposure afforded for liberation of the left ventricle, and in special situations when sternotomy might be hazardous (e.g., patent left internal mammary artery (LIMA) graft at high risk of injury).

All things being equal, median sternotomy is a better approach when CPB is used, although CPB can be used with the anterolateral approach by cannulating the femoral vessels (see Special Situations and Controversies of Chapter 2 ). The Mayo group favors median sternotomy ( Fig. 18.3 , Fig. 18.4 , Fig. 18.5 , Fig. 18.6 ) and liberal use of use of CPB to assist in performing complete pericardiectomy. ^{, ,}

View of the surgical field after removal of the diaphragmatic pericardium and a portion of pericardium posterior to the left (Lt.) phrenic nerve. Note the small strip of residual pericardium beneath the phrenic nerves and in the oblique sinus posterior to the left atrium. IVC , inferior vena cava; Rt. , right.

(From Hemmati A. Contemporary techniques of pericardiectomy for pericardial disease. Cardiol Clin . 2017;35(4):559-566.)

An additional benefit of the median sternotomy approach is the ability to address associated cardiac comorbidity. Pericardiectomy and release of constriction may lead to right ventricular and tricuspid anular dilation with worsening of functional valve regurgitation. ^, Intraoperative transesophageal echocardiography is an important adjunct to address this issue. If there is moderate or worse tricuspid valve regurgitation after separation from CPB, then tricuspid valve repair is indicated, as untreated significant tricuspid valve regurgitation is associated with reduced long-term survival. ^,

A high-speed burr or ultrasonic dissector may help to define the epicardial layer and dissect the adherent calcified pericardium away from the myocardium. ^, Complete resection of all thickened and constrictive epicardium is as important for achieving a good result with complete removal of the parietal pericardium. However, in some patients (particularly those with postoperative or postirradiation constriction), it is impossible to develop a consistent plane of dissection. In cases in which the epicardial peel is exceptionally adherent, a cross-hatching “waffle” procedure described by Heimbecker and colleagues or multiple incisions of the peel (turtle cage operation) allow myocardial expansion and restoration of adequate hemodynamics. ^{, ,}

Postoperative care is given as described in Chapter 4 . Low cardiac output early postoperatively occurs commonly in patients who have advanced disability, fluid retention, and ascites preoperatively. Low cardiac output may require maintaining left atrial pressure at a relatively high level (15 mmHg or more) and using catecholamine infusions for prolong periods of time. Intraaortic balloon pulsation is effective in these patients when cardiac output is low and unresponsive to other measures.