ConstrictivePericarditis Mike Poullis
The pericardium • Two-layered sac that encircles the heart • Inner serosal layer ( visceral pericardium ) adhering to the outer wall of the heart • Reflected at the level of the great vessels • Joins the tough fibrous outer layer ( parietal pericardium ). • A thin film of fluid ( about 50 ml ) slightly separates the two layers and decreases friction between them.
Function of pericardium • Fixes the heart within the mediastinum and limits its motion; • Prevents extreme dilatation of the heart during sudden rises of intracardiac volume • Function as a barrier to limit spread of infection from the adjacent lungs. • But patients with complete absence of the pericardium (congenital or surgically) generally do fine without it, casting doubt on its actual physiologic importance.
Pathology of Constrictive Pericarditis • Present when a fibrotic, thickened, and adherent pericardium restricts diastolic filling of the heart. • An initial episode of acute pericarditis, which may not be detected clinically. • Organisation & resorption of effusion • Fibrous scarring and thickening of the pericardium • Obliteration of the pericardial space • Uniform restriction of filling of all heart chambers. • Calcium deposition may contribute to stiffening of the pericardium.
Importance of Constrictivepericarditis • Although uncommon, commandssubstantial clinical interest because of the perceived potentialfor surgical cure. • In the past 15 years, the spectrum of CP, characterizedchiefly by a declining incidence of tuberculous pericarditisand an increase in the frequency of cases resulting from therapeuticmediastinal radiation and cardiac surgery
Clinical Features - Symptoms and signs • Reduced cardiac output (fatigue, hypotension, reflex tachycardia) • Elevated systemic venous pressure (jugular venous distension, hepatomegaly with marked ascites and peripheral edema) • Pulmonary venous congestion (exertional dyspnea, cough and orthopnea) • Chest pain typical of angina may be related to underperfusion of the coronary arteries or compression of an epicardial coronary artery by the thickened pericardium.
JVP sign’s. • Friedrich’s sign - rapid Y decent in JVP • Kussmauls’s sign - increasing JVP with inspiration A C V Z X Y
Clinical catch • Because the most impressive physical findings are often the insidious development of ascites of hepatomegaly and ascites, such patients are often mistakenly thought to suffer from hepatic cirrhosis or an intra -abdominal tumor. It is only after a careful inspection of the jugular veins that a cardiac source is identified.
Differential • Clinically, it is important to distinguish constrictive pericarditis from restrictive cardiomyopathy- each of which have similar clinical presentations and hemodynamic alterations
Pathophysiology • Constriction of pericardium results in elevation and equilibrium of all 4 cardiac chambers • In early diastole, when intracardiac volume is less than stiff pericardium, diastolic filling is unimpeded and early diastolic filling abnormally rapidly because venous pressure is elevated. • Rapid early diastolic filling is abruptly halted when the intracardiac volume reaches the limit set by the noncompliant pericardium.
Atrial Naturetic Peptide • Elevated in CCF • Normal in constrictive pericarditis • Elevated after pericardectomy • Normalises • atrial stretch hypothesis
ECG • Atrial arrhythmias may be present. • The amplitude of the QRS complexes and T waves may be diminished. • The QRS complex may be abnormal in addition to exhibiting low voltage. • The mean QRS vector is usually directed normally but may shift to the right. • Abnormal initial QRS forces and bundle branch block may occasionally occur due to calcification of the deeper portion of the myocardium.
CXR • Normal or mildly enlarged cardiac silhouette • Calcification of the pericardium is detected in up to 50% - not specific • A calcified pericardium is not necessarily a constricted one. • Lateral CXR shows the atrioventricular groove & the anterior and diaphragmatic surfaces of the right ventricle. • Pleural effusions are present in about 60 % • Persistent unexplained pleural effusions can be the presenting manifestation.
CT • Pericardial calcification is best appreciated on CT
MRI • Normal pericardium appears curvilinear as a low signal intensity situated between the high signal intensity of the pericardial and epicardial fat • Normally 1 to 2 mm in thickness - a width of up to 4 mm is not necessarily pathologic. • Small quantities of pericardial fluid may be seen normally in the superior pericardial recess (posterior to the ascending aorta). • A pericardial thickness of greater than 4 mm is considered evidence of constrictive pericarditis in the appropriate clinical setting.
Caution of radiology • History of cardiac surgery or post-pericardiotomy syndrome • Both have significant pericardial thickening in the absence of clinical symptoms. • Absence of pericardial thickening does not exclude constrictive pericarditis
Echocardiography • Echocardiographic evidence is subtle • Pericardium, if well imaged, is thickened • Ventricular cavities are small and contract vigorously • Diastolic filling terminates abruptly in early diastole (doppler flow analysis) • Doppler echocardiography often shows the dissociation of intrathoracic and intracardiac pressures through respiratory changes in mitral flow velocities. • E - A Reversal
Doppler • mitral valve (MV) inflow (A) and hepatic vein (HV) Doppler velocity recording (B) in constrictive pericarditis. • high E and small A velocities. EXP E velocity is 33% higher than INSP
Cardiac catheterization • Elevation and equalization of the diastolic pressures in all cardiac chambers • Right and left ventricular tracings show an early diastolic "dip-and-plateau " • Right atrial pressure tracing shows a prominent Y descent • Findings similar to restrictive cardiomyopathies, (suggested by a right ventricular systolic BP > 60 mm Hg) and LVDP exceeding RVDP by more than 5 mm Hg • Endomyocardial biopsy can distinguish these
Catheter pressures • Elevated RV diastolic pressure, dip-and-plateau waveform ("square root sign"), large P waves (arrow) • Postoperative decreased RV diastolic pressure normalization of dip-and-plateau & P-wave
Constrictive pericarditis vs restrictive cardiomyopathy • group 1 constrictive pericarditis • group 2 other causes of heart failure. • Open circles are group 2 with restrictive cardiomyopathy
Management • Chronic constrictive pericarditis is a progressive irreversible disease • Minority survive for years with modest elevated JVP and peripheral edema that is controlled by diet and diuretics. • Drugs that slow HR, eg beta blockers and Ca2+ channel blockers should be avoided as mild sinus tachycardia is a compensatory mechanism. • The majority of patients become progressively more disabled and subsequently suffer the complications of severe cardiac cachexia.
Management (cont) • Treatment for constrictive pericarditis is complete resection of the pericardium. • Attention must also be paid to the presence of associated right atrial thrombosis, which can partly obstruct the tricuspid valve and should be managed with thrombectomy at the time of pericardiectomy. • Concomitant CABG +/- other • Changes in technique have included the use of median sternotomy rather than left thoracotomy • CPB controversial
Operative Mortality • The operative mortality is between 5 and 20 % • Low output syndrome occurring in up to 30 % of patients in the immediate postoperative period • Symptomatic improvement can be expected in about 90 % • Complete relief of symptoms in 50 %. • Five year survival ranges from 75-85 %
Exclude • Pericardiectomy probably should not be routinely attempted in • Elderly patients with severe liver dysfunction • Cachexia • Densely calcified pericardium • Massive cardiac enlargement indicating myocardial damage • Patients with limited life expectancy.
Delayed cure • May be delayed for weeks to months after surgery • Incomplete pericardial resection (sometimes the visceral pericardium must also be resected) • Myocardial atrophy or fibrosis caused by the inflammatory process • Development of recurrent cardiac compression by mediastinal inflammation and fibrosis.
Not just the heart • Involvement of adjacent pleuropulmonary structures by the constrictivedisease process and concomitant chronic obstructive lungdisease with limited functional recovery occurs in nearly a fifth of patients • These mechanisms are not mutually exclusive in individualcases.