Vakhtang Tchantchaleishvili, MD, and Peter A. Knight, MD
Concept
- Causes of chronic pericardial disease
- Pathophysiology, physical findings and diagnostic workup
- Operative indication
- Critical operative steps
- Alternative scenarios
- Pearls/pitfalls
Chief complaint
“A 67-year-old man who was treated for stage II thymoma, including thymectomy done two years ago by you returns with fatigue, dyspnea on exertion, and peripheral edema.”
Differential
Radiation-induced chronic pericarditis, congestive heart failure, restrictive cardiomyopathy, recurrence of malignancy
History and physical
Inquire about duration, progression and severity of symptoms. Inquire about dyspnea at rest or orthopnea. Ask about risk factors for constrictive pericarditis such as history of acute pericarditis, infections, renal failure, lupus, rheumatoid arthritis, radiation, prior MI, trauma or cardiac surgery. On physical examination, look for evidence of decreased atrial filling and elevated RV diastolic pressure – jugular venous distention, hepatomegaly, peripheral edema, ascites, decreased breath sounds (effusions) and pericardial knock (early rapid ventricular filling with elevated pressures during diastole – “S3”).
Tests
Purpose of these tests are to confirm the diagnosis of constrictive pericardial disease and differentiate it from restrictive myocardial disease. The later is treated by transplantation and not pericardial stripping. The CT scan/MRI/echo showing pathology of the surrounding pericardium often gives the most valuable information for making this distinction. The physiology of constrictive pericarditis becomes evident on cardiac catheterization, echo or physical exam. The primary problem is decreased atrial and ventricular compliance. This “stiffness” results in higher atrial pressures with rapid filling of the ventricle during diastole. The stiff ventricles give off an audible S3 during diastole. On cardiac catheterization the ventricular pressure readings show a classic square root sign (rise in ventricular pressure at end diastole). During inspiration the preferential inflow to the right heart over the left is met with increased RV stiffness leading to the classic bowing of the RV to the LV seen on echo. This discordance shows up on catheter derived pressure tracings.
- CXR: pericardial calcification (40%) or signs of compression.
- CT scan or MRI: (90% sensitivity) helpful in visualizing thickened and/or calcified pericardium.
- EKG: non-specific ST-T changes.
- Echo: constrictive physiology = bowing of the interventricular septum to the left with inspiration, thickened pericardium.
- Cardiac catheterization pressure readings suggestive of constrictive pericarditis: square root sign, RV end diastolic pressure greater than ⅓ of the RV systolic pressure, equalization of pressures across the atria during diastole, equalization of pressures across the ventricles during end diastole (except during inspiration).
- Distinguishing features of restrictive disease: small or normal size heart, reduced LV function, pulmonary and hepatic congestion, prominent x and y descents on atrial pressure readings. If diagnosis is still in doubt, endomyocardial biopsy or ultimately mini- exploratory thoracotomy with inspection of the pericardium. BNP levels are not elevated with constrictive pericardial disease, but may be significantly increased with restrictive cardiomyopathy.
Index scenario (additional information)
“The patient had radiation in addition to thymectomy. His fatigue and dyspnea on exertion has been going on for several months. Recently he developed peripheral edema. Jugular venous distension is noted. On physical exam, there is systolic retraction and a pericardial knock. CXR demonstrates pericardial calcification. There are nonspecific ST-T changes on EKG. Right and left heart catheterization shows a square root sign, elevated RV end diastolic pressures with equalization of right and left atrial pressures during diastole. How do you proceed?”
Treatment/management
The patient has a radiation-induced chronic constrictive pericarditis. The basis of the disease is formation of pericardial scar from a wide range of pathologic processes (infectious, postoperative, therapeutic radiation), which results in compromised filling of the ventricles and leads to venous congestion and low cardiac output. Surgery is curative for constrictive pericarditis, thus the diagnosis in the setting of symptoms is a general indication for pericardial stripping. As mentioned, it is imperative to differentiate constrictive pericardial disease from restrictive cardiomyopathy which, despite similar clinical presentation, is not an indication for pericardial stripping. Notably in some cases like radiation-induced heart disease, there may be a concurrent presence of both conditions. If only minimally symptomatic from constrictive pericardial disease, patients with serious concomitant disease may forgo surgery. Although surgery improves or alleviates symptoms in vast majority of patients, long term survival is diminished in patients with radiation induced constrictive pericarditis.
Operative steps
Goals – excise the pericardium from phrenic nerve to phrenic nerve anteriorly, diaphragm, AV groove and around the entrance of caval/pulmonary veins posteriorly.
- Median sternotomy is used most commonly, however some surgeons prefer a thoracotomy approach.
- You can begin the dissection on the right, but cardiopulmonary bypass is often needed for resection of the left sided heart structures.
- After developing a plane on the left side of the heart and freeing up the diaphragm it helps to retract the heart towards the right in order to dissect out the left sided pulmonary veins. Release as much as you can posteriorly along the AV groove but be careful not to injure the esophagus. Check for the TEE probe and stay clear of it.
- The lack of surgical plane can lead to significant blood loss, epicardial coronary vessels and major venous structures are at risk of damage during the dissection (refer to chapter on Venous injuries).
- Complete pericardial resection may not always be possible, especially in cases of radiation induced pericardial disease and small islands of pericardium can be left behind especially over the coronaries.
Potential questions/alternative scenarios
“You begin dissecting the right atrium and start getting small tears that you are able to oversew. You’ve lost nearly 500 mL from the atrial dissection alone and still do not have it well exposed. You experience too much hypotension to perform the left sided dissection safely. What is your cannulation strategy?”
Always have your cannulation strategy in mind prior to starting a pericardiectomy. Bypass is not always necessary, and it is hard to predict when it is. In this case, keep manual pressure over the atrial tear while you work on getting aortic access for cannulation. Once the aorta is exposed heparinize, cannulate the aorta and cannulate the atrium through the tear. Once the procedure is complete, switch to bicaval cannulation and repair the tear with a patch if needed. If you cannot expose the aorta and cannot control the tear with manual pressure then heparinize, dissect out the groin and cannulate the femoral vessels. These procedures can be difficult. Have blood available and the groins well marked prior to starting. Having the groin vessels exposed is not an unreasonable approach if you anticipate a particularly hazardous dissection.
“The patient was found to have constrictive pericardial disease. He has some fatigue but minimally decreased exercise tolerance, and no edema. He also has advanced COPD, chronic renal insufficiency, and a history of stroke with residual deficits. How would you proceed?”
Given patient’s serious concomitant disease, the operation can be delayed until more significant symptoms develop from his pericardial disease.
“The patient who is status post CABG 6 weeks ago presents to your clinic for postoperative follow-up. He has a significant dyspnea. His exercise tolerance, which initially improved after the surgery, has been worsening again. How do you proceed?”
Perform a physical exam, EKG, chest X-ray, and echo.
“Your workup demonstrated constrictive pericarditis. You take the patient to OR for pericardiectomy, however during the operation you enter one of the bypass grafts. How do you proceed?”
Go on cardiopulmonary bypass, be aware of the territory the graft supplies and its significance. Check the EKG and hemodynamics for changes. Depending on the extent of the injury and hemodynamics you could give partial dose heparin, clamp the graft and do a primary repair. Alternatively, you can do an interposition graft with vein or go on CPB, arrest the heart and do a completely new bypass.
“The patient has a remote history of lymphoma. His workup shows constrictive pericardial disease. You take him to the operating room and find large implants on the pericardium which were not visualized on preoperative imaging. How would you proceed?”
Remove a diagnostic sample of the pericardium and send for frozen pathology.
“Frozen pathology results are concerning for malignancy.”
Abort the operation and refer the patient to oncologist.
Pearls/pitfalls
- Early clinical symptoms of constrictive pericarditis include dyspnea, fatigue, decreased exercise tolerance. Late symptoms include peripheral edema, hepatic congestion and ascites. May see “square root sign” on cardiac catheterization.
- Physical examination can reveal jugular venous distention, peripheral edema, and pericardial knock.
- With diagnostic tests, look for for constrictive physiology on echocardiography, thickened and/or calcified pericardium on CT/MRI, equal end-diastolic pressures in heart chambers on cardiac catheterization.
- Pericardial stripping is curative and either completely alleviates or significantly reduces the symptoms.
- Median sternotomy is the most commonly used operative approach, however a thoracotomy can be used as well.
- Cardiopulmonary bypass is not necessary but may be needed. Thus, OR with cardiopulmonary bypass capability is preferred and have cannulation options in mind ahead of time.
- The lack of surgical plane can lead to significant bleeding, epicardial coronary vessels are at risk of damage as are major venous structures (see chapter on Venous injuries).
- Long term survival is diminished in patients with radiation induced constrictive pericarditis.
Suggested readings
- Cho YH, Schaff HV. Surgery for pericardial disease. Heart Fail Rev. 2012 Aug 15.
- Napolitano G, Pressacco J, Paquet E. Imaging features of constrictive pericarditis: beyond pericardial thickening. Can Assoc Radiol J. 2009 Feb;60(1):40-6.
- Leya FS, Arab D, Joyal D, et al. The efficacy of brain natriuretic peptide levels in differentiating constrictive pericarditis from restrictive cardiomyopathy. J Am Coll Cardiol. 2005 Jun 7;45(11):1900-2.
