© 2006 WebMD, Inc. All rights reserved.                                                    ACS Surgery: Principles and Pra...
© 2006 WebMD, Inc. All rights reserved.                                                                   ACS Surgery: Pri...
© 2006 WebMD, Inc. All rights reserved.                                                      ACS Surgery: Principles and P...
© 2006 WebMD, Inc. All rights reserved.                                                           ACS Surgery: Principles ...
© 2006 WebMD, Inc. All rights reserved.                                                    ACS Surgery: Principles and Pra...
© 2006 WebMD, Inc. All rights reserved.                                                     ACS Surgery: Principles and Pr...
© 2006 WebMD, Inc. All rights reserved.                                                            ACS Surgery: Principles...
© 2006 WebMD, Inc. All rights reserved.                                                       ACS Surgery: Principles and ...
© 2006 WebMD, Inc. All rights reserved.                                                                                   ...
© 2006 WebMD, Inc. All rights reserved.                                                                                 AC...
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Acs0412 Pericardial Procedures


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Acs0412 Pericardial Procedures

  1. 1. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 1 12 PERICARDIAL PROCEDURES Shari L Meyerson, M.D., and Thomas A. D’Amico, M.D., F.A.C.S. Surgical procedures are performed on the pericardium either for The pericardium surrounds the heart and the great vessels [see diagnostic purposes or for relief of the hemodynamic conse- Figure 1]. Its parietal and visceral surfaces meet superiorly at the quences of pericardial disease.The pericardial processes for which ascending aorta and the superior vena cava. From that point, it intervention is required can be divided into two broad categories: continues down the right border of the heart and over the anteri- pericardial effusion and constrictive pericarditis. The decisions or surface of the pulmonary veins to the inferior vena cava. After that must be made regarding the selection of patients, the timing crossing the inferior vena cava, the inferior pericardium is densely of surgery, and the choice of technique or approach often pose adherent to the diaphragm. Just past the apex of the heart, it turns substantial challenges to the surgeon. Accordingly, a thorough superiorly again and runs over the pulmonary veins back to the knowledge of the anatomy, physiology, and pathophysiology of the aorta. pericardium is essential for successful management of pericardial Anteriorly, there are normally no connections between the vis- disease processes. ceral and parietal layers of the pericardium. Posteriorly, the pat- tern of pericardial reflections around the pulmonary veins and the venae cavae creates two sinuses. The oblique pericardial sinus is Anatomic and Physiologic Considerations the space in the center of the pulmonary veins, directly behind the left atrium. The transverse pericardial sinus is bordered anteriorly ANATOMY by the aorta and the main pulmonary artery and posteriorly by the Like the pleura, the pericardium consists of two layers. The dome of the left atrium and the superior vena cava. inner layer, the visceral pericardium (or epicardium), is a mono- PHYSIOLOGY layer of mesothelial cells that is adherent to the heart. The outer layer, the parietal pericardium, is a tough fibrous structure com- The pericardium is normally filled with 15 to 50 ml of serous posed of dense bundles of collagen fibers with occasional elastic fluid, which serves as lubrication to facilitate the motion of the fibers.The fibrous structure of this layer renders the pericardial sac heart within this structure. By virtue of its relative noncompliance, relatively noncompliant, and this noncompliance plays a signifi- the pericardium exerts an influence on cardiac hemodynamics. cant role in pericardial function and pathophysiology. This influence can easily be seen in the normal inspiratory varia- Aorta Superior Vena Cava Pulmonary Artery Transverse Sinus Pulmonary Veins Pulmonary Veins Oblique Sinus Inferior Vena Cava Figure 1 Shown is a view of the pericardium with the heart removed.
  2. 2. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 2 Table 1 Causes of Constrictive Pericarditis cause of constrictive pericarditis, and it is still the dominant infec- tious cause in many developing countries today.1,2 In the United Unknown States, tuberculosis is the cause of constrictive pericarditis in ap- Infection proximately 6% of patients who undergo pericardiectomy.3 Con- Tuberculosis strictive pericarditis also occurs after instrumentation of the peri- Viral infection (coxsackievirus B) cardium and is seen occasionally (in 0.2% to 0.3% of cases) after Bacterial infection cardiac surgery.4,5 It also may develop after iatrogenic cardiac per- Fungal infection (histoplasmosis, coccidioidomycosis) foration in the course of catheterization or pacemaker placement Parasitic infection (amebiasis, echinococcosis) and after blunt or penetrating trauma—essentially, after any Cardiac surgery or pacemaker insertion Common causes Penetrating, nonpenetrating, or iatrogenic trauma process resulting in an incompletely drained hemopericardium.6,7 Radiation therapy The pericardium may harbor metastatic disease or locally Connective tissue disorders (rheumatoid arthritis, sys- advanced disease (e.g., mesothelioma), which may lead to peri- temic lupus erythematosus, scleroderma) cardial constriction.8,9 Connective tissue disorders (e.g., rheuma- Renal failure toid arthritis and lupus) can cause recurrent acute pericarditis and Neoplasm pericardial effusions, eventually resulting in constrictive pericardi- Metastatic disease (breast, lung, lymphatic system, skin) tis. A similar situation may arise in patients receiving radiation Primary mesothelioma therapy and patients with renal failure. Drugs (procainamide, methysergide, hydralazine) The stiffening and thickening of the pericardium have three Myocardial infarction major physiologic effects. First, the thicker pericardium isolates Asbestosis the heart from changes in intrathoracic pressure. Normally, the Amyloidosis Sarcoidosis pulmonary veins (which are intrathoracic structures) and the car- Uncommon diac chambers experience the same changes in intrathoracic pres- causes Dermatomyositis Actinomycosis sure. In the presence of pericardial constriction, however, the neg- Lassa fever ative intrathoracic pressure generated during inspiration cannot Whipple disease be transmitted to the heart. This isolation of the heart results in Mulibrey nanism decreased flow through the pulmonary veins during inspiration and reduced left-side filling. Second, the ventricles become interdependent. Because total tion in systemic arterial pressure. Under normal circumstances, pericardial volume does not change, the inspiratory decrease in intrapericardial pressure is slightly less than 0 mm Hg, becoming left ventricular filling seen with constriction must be accompanied more negative during inspiration and less negative during expira- by an increase in right ventricular filling, with a resultant septal tion. Negative intrathoracic pressure during inspiration augments shift toward the left ventricle. During expiration, the opposite right ventricular filling. Because the pericardium does not allow occurs: left ventricular filling increases and right ventricular filling significant acute right ventricular dilation, the ventricular cavity decreases, and there is a septal shift toward the right ventricle. enlarges by shifting the septum toward the left ventricle. In addi- Third, the encasement of the heart impairs the diastolic filling tion, the noncompliance of the pericardium prevents the free wall of all cardiac chambers. Elevated atrial pressure causes rapid ini- of the left ventricle from distending to recapture its normal cavi- tial filling of the ventricle (with as much as 75% of the ventricle tary volume. Thus, the volume ejected from the left ventricle is filled during the first 25% of diastole), but by the middle of dias- slightly decreased, resulting in lower systemic arterial pressure. tole, filling abruptly decreases as a result of the rigid pericardium. Normally, this effect is exceedingly small. However, it becomes Because of this limit to diastolic filling, increasing the heart rate more pronounced when the pericardium is filled with fluid: ven- becomes the most effective method of increasing cardiac output.10 tricular distention is restricted even further, and paradoxical pulse becomes clinically apparent. Pericardial Drainage Procedures for Pericardial Effusion Although the pericardium is resistant to rapid distention, it is capable of distending over time. If filled slowly, it can expand to A number of different processes can result in the accumulation contain significant amounts of fluid (sometimes more than 1 L) of fluid in the pericardial space [see Table 2]. Regardless of the ori- before hemodynamic consequences develop. In the setting of an gin of the fluid accumulation, once the pericardium has reached acute pericardial effusion (e.g., from trauma), however, devastat- the limits of its elasticity, the only way in which it can increase its ing hemodynamic consequences may occur with only 100 to 200 volume is by reducing the volume occupied by the heart within it. ml of blood in the pericardium. When the elastic capacity of the Increases in pericardial pressure result in progressive cardiac com- pericardium is exceeded, even small increases in volume cause pression and reductions in intracardiac volumes and myocardial large increases in intrapericardial pressure. Constrictive pericarditis is defined as a chronic fibrous thicken- ing of the pericardium that causes cardiac compression sufficient Table 2 Common Causes of Pericardial Effusion to prevent normal diastolic filling. It can best be thought of as the chronic sequela of acute pericarditis or of any situation resulting in Malignancy Myocardial infarction pericardial irritation and adhesion formation. Almost any cause of Trauma Iatrogenesis (intracardiac acute pericarditis can result in pericardial constriction [see Table 1]. Uremia procedures) Infection (viral, bacterial, fungal, Aortic dissection In many patients, there is no clear antecedent event, and the cause tubercular) Radiation of the constrictive pericarditis cannot be determined with certain- Autoimmune processes Idiopathic origin ty. Pathologic examination typically demonstrates end-stage fibro- Cardiac surgery (postoperative sis, and these cases are presumed to be viral in origin. Historically, complication) mycobacterial tuberculosis has been the most common infectious
  3. 3. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 3 diastolic compliance.This effect is most pronounced in the cham- bers with the lowest normal intracavitary pressures—namely, the right atrium and the right ventricle.11 Changes in systemic cardiac output occur as a result of right heart compression, which leads to diminished right ventricular stroke volume, reduced pulmonary blood flow, and decreased left ventricular filling. In the early stages of pericardial effusion, various compensatory changes act to pre- serve cardiac output. Such changes include an increased ejection fraction, tachycardia, increased intravascular volume via renal con- servation of salt and water, increased peripheral vascular resis- tance, and time-dependent pericardial stretch.12,13 PREOPERATIVE EVALUATION The presenting symptoms of pericardial effusion may be non- specific and related to the underlying disorder (e.g., fever, chest pressure, and fatigue). Fluid accumulation that is substantial enough to have hemodynamic consequences is defined as cardiac tamponade. Patients with early tamponade may have dyspnea, tachycardia, mild hypotension, decreased urine output, and para- doxical pulse. As tamponade progresses, patients may manifest Figure 2 Computed tomography demonstrates right pleural and signs of end-organ hypoperfusion (e.g., mental status changes, pericardial effusions, for which a right thoracoscopic approach is renal insufficiency, and shock). The classic physical findings ideal. known as Beck’s triad (i.e., jugular venous distention, systemic hypotension, and distant heart sounds) are more common with acute tamponade (such as results from trauma) than with slow- cardiocentesis, subxiphoid pericardiostomy (pericardial win- developing tamponade (such as results from medical processes). dow), and thoracoscopic pericardiostomy (via either the right In patients with slow-developing tamponade, systemic fluid reten- or the left pleural space). The choice of a surgical approach to tion is observed, often manifested by peripheral edema or ascites. the pericardial space depends on the clinical condition of the Most commonly, pericardial effusion is diagnosed when a patient, as well as on the underlying diagnosis (if known). Pa- patient exhibits new symptoms in the context of an underlying tients with tamponade may decompensate rapidly during the disorder associated with pericardial effusion (e.g., renal failure or vasodilatation and positive pressure ventilation associated with malignancy). Chest x-rays may reveal a globular heart or an general anesthesia. Accordingly, careful consideration must be increasing cardiac silhouette on serial films. Currently, echocar- given to the type of anesthesia employed for pericardial drain- diography is the most commonly employed and most useful age procedures. modality for the diagnosis of pericardial effusion: it reliably deter- Pericardiocentesis is routinely done with local anesthesia only, mines the presence, location, and relative volume of fluid accu- and it may be the best choice in an acutely unstable patient with mulations. In many cases, echocardiography can identify early tamponade. If this option is chosen, however, the choice must be tamponade, often before symptoms develop. A variety of echocar- made with the understanding that pericardiocentesis, because of its diographic findings have been associated with pericardial effu- high recurrence rate and its limited diagnostic capacity, is unlikely sion, of which the most useful are right atrial collapse and right to constitute definitive therapy. Subxiphoid pericardiostomy is gen- ventricular collapse. Right atrial collapse during late diastole erally done with initial local anesthesia followed by induction of tends to occur early in the development of tamponade because of general anesthesia, and most patients with tamponade can under- the normally low right atrial filling pressures. Right ventricular go this procedure.The subxiphoid approach provides the hemody- free wall collapse during early diastole suggests progression of namic benefits of pericardiocentesis, offers the enhanced diagnos- tamponade. Other useful signs are loss of the normal inspiratory tic capability of pericardial biopsy, and has a low recurrence rate. collapse of the inferior vena cava and an increase in right ventric- Consequently, it is the procedure of choice for patients with tam- ular diameter with a reciprocal decrease in left ventricular diam- ponade who are stable enough to be transported to the operat- eter during inspiration. ing suite. Thoracoscopic pericardiostomy has the advantage of In patients who are undergoing invasive hemodynamic moni- enabling simultaneous treatment of pleural processes, which are toring (e.g., those who have just undergone cardiac surgery), commonly present in these patients [see Figure 2]. Ipsilateral pleur- hemodynamic findings suggestive of tamponade include elevation al and pericardial spaces can be fully explored, pleural effusions can of right atrial pressure and equalization of right atrial pressure and be drained, loculations can be divided, and biopsy specimens can pulmonary capillary wedge pressure. It is important to remember, be obtained as needed. The thoracoscopic approach can be espe- however, that localized tamponade can occur (especially in the cially useful in the case of a known loculated effusion that is limit- postoperative period) without these changes. A common cause is ed to one area of the pericardium, in that a pericardial window can localized clot in the oblique pericardial sinus behind the left atri- be created via either pleural space.This approach also allows resec- um, which causes reduced left atrial compliance. tion of a larger segment of pericardium, which may improve the diagnostic yield and reduce the likelihood of recurrent effusion. OPERATIVE PLANNING The major limitation of thoracoscopic pericardiostomy is the need for lung isolation and lateral positioning, which should not be Choice of Procedure attempted in patients with evidence of tamponade. By weighing the There are three procedures that are commonly performed for relative risks and benefits of these three procedures, the surgeon surgical diagnosis and treatment of pericardial effusion: peri- can choose the optimal approach for each patient.
  4. 4. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 4 PERICARDIOCENTESIS centesis, successful fluid removal with symptomatic relief was achieved in 97.1% of cases.16 Of the 139 patients, 2.9% experi- Operative Technique enced complications (e.g., pneumothorax and ventricular lacera- Pericardiocentesis is performed either at the bedside in an tion), and one (0.7%) died. In all, 45 of the patients received no urgent situation or, preferably, under echocardiographic guidance further therapy, and in 25 (55%) of the 45, recurrent effusions in a catheterization laboratory. The basic technique is simple. developed that necessitated reintervention. Several techniques for preventing recurrent pericardial effusion Step 1: placement of needle A local anesthetic is infiltrated have been tried. Instillation of a sclerosing agent (e.g., tetracycline, along the left side of the xiphoid. An 18-gauge spinal needle thiotepa, or bleomycin) into the pericardium to promote fusion attached to a three-way stopcock and syringe is then advanced into of the two layers of the pericardium has been shown to increase the pericardial space and directed cephalad toward the left shoul- the success rate of pericardiocentesis by as much as 85%.17-19 der at a 45° angle until fluid is aspirated [see Figure 3]; if air is aspi- Placement of an indwelling catheter (see above) also has been rated, the needle is withdrawn and redirected more medially. Once shown to improve the success rate.16,20 Several authors have fluid is aspirated freely, it is inspected. If the fluid is bloody, 5 ml described creating a pericardial window percutaneously by means is withdrawn and placed on a sponge. If the fluid on the sponge of balloon dilation of the tract created by pericardiocentesis, which clots, it is fresh blood, probably from a cardiac injury occurring theoretically allows fluid to drain into the pleural space or the sub- during the procedure or from intracardiac positioning of the nee- cutaneous tissues, where it can be absorbed.21,22 However, it is dle; blood that has been in the pericardium for even a short time unclear how long a window created in this fashion will remain becomes defibrinated and will not clot.14 patent. Although pericardiocentesis provides initial symptomatic relief in most patients, the observation that 15% to 45% of Troubleshooting. The inherent danger of cardiac injury during patients require a further procedure for diagnosis and as many as pericardiocentesis should be obvious.The risk is highest with small 55% require reintervention for recurrence has led some authori- or loculated effusions and patients with coagulation abnormalities. ties to question its benefit. The possibility of cardiac aspiration or injury can be minimized, SUBXIPHOID PERICARDIOSTOMY (PERICARDIAL WINDOW) though not eliminated, by means of various safety measures. The simplest of these measures is to attach an ECG lead to the needle and employ continuous ECG monitoring. If the needle contacts Operative Technique the epicardium, ST segment elevation will be observed, in which Subxiphoid pericardiostomy may be performed either to diag- case the needle is withdrawn until the ST elevation disappears. nose pericardial effusion or to manage tamponade. For diagnosis, Another useful safety measure is to employ echocardiographic the procedure is usually done with general anesthesia. In an unsta- guidance to help direct aspiration of a loculated area. Simulta- ble patient with significant tamponade, who would be at risk for neous cardiac catheterization has also been used to locate the right hemodynamic collapse with general anesthesia, the procedure may coronary artery and the atrioventricular groove. be performed with the patient under local anesthesia and mild sedation and breathing spontaneously. If there is any question of Step 2: placement of drainage catheter and aspiration of tamponade, the patient is prepared and draped while awake, and fluid Once the needle is within the pericardial space, a guide anesthesia is induced only when the surgeon is ready to begin. In wire is placed through it, and a small-bore drainage catheter is all patients, the entire chest should be prepared, in case a full ster- advanced into the effusion by means of a modified Seldinger tech- notomy is required. Ideally, the patient is sedated and the airway nique. Fluid is aspirated and sent for laboratory evaluation (in- cluding cell count, chemistry, culture, and cytology). The cathe- ter is then connected to a closed drainage system for 24 to 72 hours; this may help reduce recurrence. Complications The most common complications of pericardiocentesis are pneumothorax, cardiac injury, misdiagnosis, and recurrence of pericardial effusion. In every patient undergoing pericardiocente- sis, pneumothorax must be ruled out by means of chest x-ray at the completion of the procedure or, if respiratory or hemodynam- ic changes develop intraoperatively, during the procedure. Cardiac injuries range from minor needle lacerations to the epicardium, which are self-limited in patients with normal coagulation param- eters, to potentially fatal injuries that lead to acute cardiac tam- ponade. Incorrect diagnoses based on pericardiocentesis are not uncommon. Although a diagnosis can be confirmed by positive results from fluid culture or cytology, negative results from cytol- ogy do not rule out malignant effusion. Cytologic analysis of peri- cardial fluid is diagnostic in only 55% to 85% of patients.15 Further diagnostic maneuvers often must be undertaken, usually involving subxiphoid or thoracoscopic approaches with pericardial biopsy. Recurrence of pericardial effusion after pericardiocentesis is extremely common. In a review that included 139 patients with Figure 3 Pericardiocentesis. The needle is angled toward the left malignant pericardial effusions who were treated with pericardio- shoulder at an angle of 45°.
  5. 5. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 5 b a Figure 4 Subxiphoid pericardiostomy. (a) A small vertical incision is made from the xiphisternal junction down to a point just below the tip of the xiphoid, the upper extent of the linea alba is divided, and the xiphoid is removed. (b) The pericardium is opened, and the edge of the opening is grasped and elevated. A pericardial specimen several square centimeters in size is then resected to create the pericardial window. controlled while spontaneous respiration is maintained to mini- to the pericardium. Upon entry into the pericardium, there is an mize hemodynamic effects. If necessary, a local anesthetic may be initial outrush of fluid. A sanguineous effusion can be difficult to infiltrated and the incision made before induction of anesthesia. differentiate from cardiac injury; therefore, the patient’s hemody- namics should be carefully monitored during this time. When the Step 1: initial incision and exposure of pericardium A pressure placed on the heart by an effusion is released, blood pres- small vertical incision is made from the xiphisternal junction down- sure will usually rise and heart rate fall; however, if the heart has ward to a point slightly below the tip of the xiphoid process [see been accidentally injured, the opposite will occur. Once hemody- Figure 4a]. The upper extent of the linea alba is divided, with care namic stability is achieved, administration of a diuretic (e.g., furo- taken not to enter the peritoneum. Peritoneal openings are easily semide) should be considered to reduce the risk of pulmonary repaired but can make the procedure technically more difficult, in edema developing as a result of systemic fluid retention. that abdominal contents tend to impede visualization, especially in spontaneously breathing patients. The soft tissue attachments to Step 3: creation of pericardial window Pericardial fluid is the xiphoid are divided, the veins running along either side of the collected for microbiologic and cytologic analysis and for any xiphoid are controlled, and the xiphoid process is removed. additional testing suggested by the clinical scenario. The pericar- The tissue plane behind the lower sternum is developed by dial space is gently explored with the fingers, and all remaining means of blunt dissection.This maneuver exposes the retrosternal fluid is evacuated. The edge of the pericardial opening is grasped space to allow visualization of the pericardium. To enhance expo- with a clamp and elevated [see Figure 4b]. A pericardial specimen sure, the sternum is retracted upward by an assistant. The anteri- several square centimeters in size—or as large as can safely be or pericardial surface is then exposed by sweeping away the re- managed—is resected and sent for pathologic and microbiologic maining mediastinal fat. If necessary, the confluence of the peri- analysis. cardium and the diaphragm may be retracted caudally to improve exposure. Step 4: drainage and closure A separate stab incision for drain placement is made below and to one side of the lowermost Step 2: opening of pericardium The location of the peri- aspect of the skin incision. Bringing the drainage tube out through cardial incision can be confirmed by palpating cardiac motion a separate incision helps prevent incisional complications (e.g., through the exposed pericardium.The pericardium is then opened infection and hernia). A 24 to 28 French chest tube (either straight with a scalpel; shallow strokes should be employed to reduce the or right-angle) is tunneled through the fascia at the entry site so chances of injuring underlying myocardium that may be adherent that it lies beneath the divided linea alba in the preperitoneal
  6. 6. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 6 space. The tube is then directed through the pericardial window racoscopic pericardial drainage necessitates single-lung ventilation and into the pericardial space and secured at skin level.The fascia and thus is unsuitable for unstable patients, especially those with at the linea alba is closed with interrupted sutures to provide tamponade. Such ventilation can be accomplished by means of secure closure and prevent late hernia; the skin and subcutaneous either a dual-lumen endotracheal tube or a bronchial blocker tissue are closed in the standard fashion. The chest tube is con- placed through a standard endotracheal tube. nected to a drainage system with a water seal. Pericardial drainage Once the tube is in place, the patient is turned to the appropri- is maintained for several days postoperatively until the output falls ate lateral decubitus position. The side of approach is chosen on below 100 ml/day. This period allows time for apposition and the basis of the location of a loculated effusion or the site of any adhesion formation between the visceral pericardium and the pari- coexisting pathologic condition (e.g., a pleural effusion or pul- etal pericardium. monary nodule). If the disease process or processes present do not Although some fluid may initially drain into the subcutaneous dictate a particular side of approach, the right side is frequently tissues and be absorbed, the name pericardial window is some- preferred. It is often easier to operate on the right side because thing of a misnomer. The surgically created window in the peri- there is more working room within the pleural space; however, cardium is unlikely to remain patent over the long term, and in operating on the left side usually allows the surgeon to create a fact, obliteration of the pericardial space has been shown to be the larger pericardial window. If tamponade is present in a patient for mechanism responsible for the success of this procedure.23,24 whom the thoracoscopic approach is desired, pericardiocentesis may be performed before induction of general anesthesia.28 Complications Complications from subxiphoid pericardiostomy are rare; Step 1: placement of ports and entry into pleural space bleeding, infection, incisional hernia, anesthetic complications, An initial camera port is placed in the posterior axillary line at the and cardiac injury have been reported. In a study that included eighth intercostal space [see Figure 5].The pleural space is entered 155 patients who underwent subxiphoid pericardiostomy over a 5- and explored, and any effusion present is drained. Pleural fluid is year period, not a single death was attributable to the operative sent separately for culture and cytologic analysis.To prevent inad- procedure itself.23 The 30-day mortality was high but was related vertent entry into the pericardium, which is often distended, a sec- to the underlying disease process: 33% in patients with malignant ond incision is created anteriorly at the fifth intercostal space effusions and 5% in those with benign effusions. Recurrent peri- under camera visualization. cardial effusion necessitating additional procedures occurred in four patients (2.5%). In a study that compared 94 patients who Step 2: opening of pericardium On the left side, the underwent subxiphoid pericardiostomy with 23 patients who un- phrenic nerve, which runs midway between the hilum and the derwent pericardiocentesis, the rate of recurrent effusion that anterior chest wall, is carefully identified, and an initial pericardial necessitated reintervention was 1.1% after subxiphoid window but incision is made approximately 1 cm anterior to this nerve. Care 30.4% after pericardiocentesis.25 In this series, the rate of major must be taken to place this first incision in an area that is free complications after the pericardial window procedure was 1.1% of cardiac adhesions. When grasped, the pericardium should tent (one patient with bleeding that necessitated reexploration), com- outward slightly. Often, cardiac motion is visible through the pared with a major complication rate of 17% after pericardiocen- pericardium. tesis (including a mortality of 4%). Several studies have shown that the most important predictor of Step 3: creation of pericardial window A pericardial win- long-term outcome is the underlying disease process. In one, the dow several square centimeters in area is removed. A similar win- median survival time was 800 days for patients with benign dis- dow may be created posterior to the phrenic nerve—again, with ease, 105 days for patients with known cancer but negative results care taken to stay at least 1 cm away from the nerve. The pericar- from pericardial cytology and pathology, and only 56 days for dial space is inspected, and any loculations are opened. The pro- patients with malignant effusions.23 It appears, however, that can- cedure is similar when performed on the right side, except that the cer patients with hematologic malignancies and pericardial effu- phrenic nerve on the right runs much closer to the hilum; accord- sion survive significantly longer than patients with other malig- ingly, instead of two pericardial windows (anterior and posterior to nancies. In another study, the mean survival time after drainage of the nerve), only a single, larger pericardial window is created pericardial effusion was 20 months for patients with hematologic (anterior to the nerve). malignancies, compared with 5 months for patients with any other In patients who can tolerate general anesthesia, a pericardial malignancies.26 The investigators suggested that this finding may window can be created thoracoscopically with excellent diagnostic be related to the relative responsiveness of hematologic cancers to yield and relief of symptoms.29 The thoracoscopic approach allows systemic chemotherapy. Patients with HIV disease have been directed access and can be useful in treating effusions that recur shown to have universally dismal outcomes after they present after subxiphoid pericardiostomy.30 with pericardial effusion. In this population, surgical pericardial drainage generally is not diagnostically revealing and is of little therapeutic value. Several authors have questioned whether peri- Pericardiectomy for Constrictive Pericarditis cardial drainage should even be offered to these patients.27 PREOPERATIVE EVALUATION THORACOSCOPIC PERICARDIOSTOMY Constrictive pericarditis appears to be about three times as common in males as in females, and it may occur at any point in Operative Technique life from childhood to the ninth decade.31 The symptoms of con- Thoracoscopic pericardiostomy is a safe and effective approach strictive pericarditis usually develop progressively over a period of to the diagnosis and management of pericardial effusion, especial- years but may develop within weeks to months after a defined ly in patients with a unilateral pleural disease process that can be inciting event (e.g., mediastinal irradiation or cardiac surgery). simultaneously addressed in the course of the procedure. Tho- Signs and symptoms are related to pulmonary venous congestion
  7. 7. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 7 4–5 cm Incision in 1.5 cm Incision in Fifth Intercostal Space Eighth Intercostal Space for Instruments for Camera Port Assistant behind Patient Surgeon in Front of Patient Figure 5 Thoracoscopic pericardiostomy. Shown are the appropriate patient positioning and the proper placement of ports and instruments. OPERATIVE PLANNING (e.g., exertional dyspnea) and systemic venous congestion (e.g., elevated jugular venous pressure, hepatomegaly, ascites, and peripheral edema). Choice of Approach The physiologic effects of the thickened pericardium form the Pericardiectomy may be performed via either a median ster- basis for the diagnosis of constrictive pericarditis and, more impor- notomy or a left anterolateral thoracotomy, with equivalent results. tant, for the differentiation of constrictive pericarditis from restric- Median sternotomy provides better access to the right atrium and tive cardiomyopathy, which often presents a similar picture. Echo- the great vessels, as well as easier access for cannulation if car- cardiography can be employed to rule out other causes of right- diopulmonary bypass is required; left anterolateral thoracotomy side failure. Specific findings that suggest pericardial constriction allows more complete release of the left ventricle. With either include septal bounce (a respiratory phase–related septal shift) and approach, the patient should undergo full monitoring, including decreased transmitral flow velocity during inspiration. Computed radial artery catheterization and central venous catheterization, tomography and magnetic resonance imaging may demonstrate with consideration given to placement of a pulmonary arterial thickened, often calcified, pericardium; however, the degree of catheter if there is significant hemodynamic compromise. Because pericardial thickening does not necessarily correlate with the pres- significant blood loss can occur when densely adherent pericardi- ence of hemodynamic effects. um is resected, large-bore intravenous access should be available as Cardiac catheterization may demonstrate increases in and equal- well. ization of end-diastolic pressure in all four cardiac chambers, a dip- OPERATIVE TECHNIQUE and-plateau pattern (the square-root sign) in the ventricular pres- sure curves as a result of rapid early filling and limited late filling, and rapid x and y descents in the atrial pressure curves. The most Median Sternotomy useful information obtainable through cardiac catheterization has Step 1: initial incision and exposure The patient is placed to do with the respiratory variation of ventricular pressure. In a in the supine position, and the skin incision is carried down to the patient with a normal heart or a patient with restrictive cardiomy- level of the sternum. If there is no history of previous pericardial opathy, inspiration causes a decrease in both right ventricular pres- procedures and it is possible to develop the plane behind the ster- sure and left ventricular pressure as a consequence of decreased num bluntly at the superior and inferior aspects, a standard ster- intrathoracic pressure. In a patient with constrictive pericarditis, notomy saw can be used for the median sternotomy. If, however, because of the interdependence of the ventricles, inspiration caus- there are likely to be adhesions between the sternum and the peri- es a decrease in left ventricular pressure but an increase in right cardium or the heart (as in the case of constrictive pericarditis after ventricular pressure.32 coronary artery bypass grafting), a careful reoperative sternotomy
  8. 8. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 8 should be performed with an oscillating saw. Access to the femoral pulmonary veins all the way over to the right pulmonary veins vessels should be available within the sterile field; placement of a (including the origins of the venae cavae). The pericardium is femoral arterial line will facilitate percutaneous cannulation in the resected from the left phrenic nerve to the right phrenic nerve [see event that the heart is injured during sternal reentry. Figure 6]. After the sternum is opened, all adhesions are dissected away Cardiopulmonary bypass can make dissection easier, but in from the sternum, with care taken to stay as close to the posterior view of the greater risk of bleeding and the increased transfusion surface of the sternum as possible. Both pleural spaces are opened, requirements, it is best avoided if possible. Cardiopulmonary by- and the left and right phrenic nerves are identified. pass does facilitate repair of cardiac injuries during sternal reentry or dissection, and it should be used if cardiac procedures are to be Step 2: dissection and resection of pericardium The performed concomitantly. phrenic nerves define the limits of pericardial resection bilaterally. Small loculated spaces are often present within the pericardium, Step 3: drainage and closure After completion of the peri- especially near the great vessels and the diaphragm, and provide cardiectomy, mediastinal and pleural drains are placed, and the good starting places for pericardiectomy. Once an initial flap is sternum is closed in the usual fashion. raised, it is used to provide retraction to facilitate further dissec- Left Anterolateral Thoracotomy tion. Careful attention must be paid to the coronary artery anato- Step 1: initial incision and exposure The patient is placed my: coronary arteries and bypass grafts are vulnerable to injury. If in the supine position, with a roll under the left side of the torso to the pericardium is densely adherent in the region of a coronary elevate the left side 45°. It is often difficult to establish cardiopul- artery, small islands of pericardium may be left on the heart. Areas monary bypass through the chest via this approach; therefore, the of calcification can be addressed with the use of bone-cutting femoral vessels should be available within the sterile field so that instruments; however, if an island of calcification appears to extend femorofemoral bypass can be instituted if necessary. A curvilinear into the myocardium, it should not be removed. submammary incision is created, and the chest is entered at the Epicardium can also be involved in the disease process and fifth interspace. For improved exposure, the internal thoracic ves- should be resected or scored until no further restriction to ventric- sels may be divided and the intercostal muscles divided posterior- ular filling remains. The heart should be dissected free of the left ly. The left phrenic nerve is carefully identified. Step 2: dissection and resection of pericardium As with the median sternotomy approach, loculated spaces are often pres- ent near the great vessels and the diaphragm, and these vessels provide good starting places for dissection. The entire pericardi- um is dissected free over the left ventricle, and an island of peri- cardium is left attached to the phrenic nerve along its length [see Figure 7]. The pericardium is resected from the pulmonary veins to a point just posterior to the phrenic nerve. Resection resumes anterior to the nerve and continues across the anterior aspect of the heart as far as possible, ideally to the right atrioventricular groove. The same precautions should be taken around the coro- nary vessels as are taken with the median sternotomy approach. Step 3: drainage and closure After completion of the peri- cardiectomy, mediastinal and pleural drains are placed, and the thoracotomy is closed in the usual fashion. OUTCOME EVALUATION There is no proven difference between the two approaches to pericardiectomy with respect to outcome. Accordingly, the choice between them is based on whether one option affords better access to the areas believed to be most involved (e.g., a median sternoto- my is more effective for releasing the right side of the heart) and whether the surgeon is more comfortable with one approach or the other. The underlying cause of constrictive pericarditis is a significant predictor of long-term survival. In a study of 163 patients who Right underwent pericardiectomy, 7-year survival rates were highest in Left Phrenic Phrenic patients with idiopathic constrictive pericarditis (88%), somewhat Nerve Nerve lower in patients with postoperative constriction (66%), and low- est in patients with radiation-induced constriction (27%).33 Pre- dictors of decreased survival included previous radiation therapy, renal dysfunction, pulmonary hypertension, and abnormal left Figure 6 Pericardiectomy: median sternotomy approach. The ventricular systolic function. Perioperative mortality was 6% over- pericardium is resected from the left phrenic nerve to the right all but 21% in patients who had received radiation therapy and 8% phrenic nerve. in postsurgical patients. The slightly higher mortality recorded in
  9. 9. © 2006 WebMD, Inc. All rights reserved. ACS Surgery: Principles and Practice 4 THORAX 12 PERICARDIAL PROCEDURES — 9 a b Aorta Pulmonary Left Anterior Descending Artery Coronary Artery Phrenic Nerve Aorta Phrenic Nerve Dissected Free Lung Figure 7 Pericardiectomy: left anterolateral thoracotomy approach. (a) The left phrenic nerve is identified. (b) The entire pericardium is dissected free over the left ventricle, with an island of pericardium left attached to the phrenic nerve along its length. Care must be taken to avoid injuring coronary vessels. postoperative patients may reflect underlying cardiac dysfunction, Another study reported similar findings, with radiation-induced as well as the vulnerability of previous bypass grafts to injury. The constriction leading to significantly decreased 10-year survival after poor outcomes after pericardiectomy for radiation-induced con- pericardiectomy.31 The authors also noted that patients who under- striction indicate that constriction is not the sole factor responsible went pericardiectomy for radiation-induced constriction had for cardiac failure in this situation. Although cardiac failure has demonstrably worse late functional status. Fifteen of 17 long-term been attributed to myocardial atrophy caused by prolonged con- survivors with a history of previous radiation therapy showed New striction, the excellent outcomes reported after pericardiectomy York Heart Association class III or IV symptoms, whereas only 31 for idiopathic constrictive pericarditis suggest that constriction is of 112 patients without a history of radiation therapy had major rarely the only cause of cardiac failure. symptoms of heart failure. References 1. Fowler NO: Tuberculous pericarditis. JAMA after a stab wound to the chest. Heart 90:276, 12. Ameli S, Shah PK: Cardiac tamponade: patho- 266:95, 1991 2004 physiology, diagnosis and management. Cardiol 2. Butany J, El Demellawy D, Collins MJ, et al: Con- 7. Isaacs D, Stark P, Nichols C, et al: Post traumatic Clin 9:665, 1991 strictive pericarditis: case presentation and a review pericardial calcification. J Thorac Imaging 18:250, 13. Spodick DH: Pathophysiology of cardiac tampon- of the literature. Can J Cardiol 20:1137, 2004 2003 ade. Chest 113:1372, 1998 3. Tuna IC, Danielson GK: Surgical management of 8. Eren NT, Akar AR: Primary pericardial mesothe- 14. Nkere UU, Whawell SA, Thompson EM, et al: pericardial diseases. Cardiol Clin 84:683, 1990 lioma. Curr Treat Options Oncol 3:369, 2002 Changes in pericardial morphology and fibrinolyt- 4. Cimino JJ, Kogan AD: Constrictive pericarditis 9. Quinn DW, Qureshi F, Mitchell IM: Pericardial ic activity during cardiopulmonary bypass. J after cardiac surgery: report of three cases and mesothelioma: the diagnostic dilemma of mislead- Thorac Cardiovasc Surg 106:339, 1993 review of the literature. Am Heart J 118:1292, ing images. Ann Thorac Surg 69:1926, 2000 15. Posner MR, Cohen GI, Skarin AT: Pericardial dis- 1989 10. Myers RBH, Spodick DH: Constrictive pericardi- ease in patients with cancer. Am J Med 71:407, 5. Matsuyama K, Matsumoto M, Sugita T, et al: tis: clinical and pathophysiologic characteristics. 1981 Clinical characteristics of patients with constrictive Am Heart J 138:219, 1999 16. Vaitkus PT, Herrmann HC, LeWinter MM: pericarditis after coronary bypass surgery. Jap Circ 11. Fowler NO, Gabel M:The hemodynamic effects of Treatment of malignant pericardial effusion. J 65:480, 2001 cardiac tamponade: mainly the result of atrial, not JAMA 272:59, 1994 6. Swallow RA, Thomas RD: Pericardial constriction ventricular, compression. Circulation 71:154, 1985 17. Shepherd FA, Morgan C, Evans WK, et al:
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