bubble_chart Overview

Pericardial effusion is a relatively common clinical manifestation, especially after echocardiography became a routine examination method for cardiovascular diseases. The detection rate of pericardial effusion in patients has significantly increased, reaching as high as 8.4%. Most pericardial effusions do not present clinical symptoms due to their small volume. However, a few patients may exhibit pericardial effusion as a prominent clinical feature due to a large accumulation. When pericardial effusion persists for several months or longer, it constitutes chronic pericardial effusion. There are various causes of chronic pericardial effusion, most of which are related to diseases that can affect the pericardium.

bubble_chart Clinical Manifestations

The condition is more common in women, with the onset often occurring during menopause. Patients can usually carry out daily work without noticeable discomfort. Symptoms, when present, often manifest as shortness of breath and chest pain. Some patients exhibit signs of pericardial tamponade in the early stages of the disease, which gradually diminish or disappear as the condition progresses. Many cases are incidentally discovered during routine physical examinations and are easily misdiagnosed as cardiomegaly. Since there is almost no history of acute pericarditis, the exact onset time of the disease is often difficult to determine. The condition demonstrates good hemodynamic tolerance. Because pericardial effusion accumulates gradually, the pericardial capacity adapts to the increasing fluid volume, allowing large effusions to cause only grade I intrapericardial pressure elevation, presenting as non-restrictive pericardial effusion. As a result, pericardial tamponade is rare or almost never occurs. Only when pericardial effusion increases suddenly and rapidly, outpacing the pericardium's adaptive expansion, does it present as restrictive pericardial effusion, potentially leading to tamponade. There have been reports of spontaneous resolution of pericardial effusion. However, since this may be related to disease cause or treatment, it remains uncertain whether chronic idiopathic pericardial effusion can resolve on its own.

bubble_chart Diagnosis

This disease still lacks a precise and unified definition. Generally, cases meeting the following characteristics are classified as this disease: ① the presence of a large amount of pericardial effusion, confirmed by UCG; ② the volume of pericardial effusion remains essentially stable during the observation period; ③ the pericardial effusion persists for at least 3 months or longer; ④ the patient has been ruled out for any systemic diseases, regardless of whether the disease may be related to pericardial effusion; ⑤ systemic disease etiology examinations are negative. This disease is sometimes referred to as "chronic exudative pericarditis" or "chronic idiopathic pericarditis," but since in most cases patients do not exhibit manifestations of pericarditis, these terms are gradually being avoided. The incidence of this disease among pericardial diseases is approximately 2% to 3.5%.

Clinically, it is often discovered through routine chest X-rays showing an enlarged cardiac shadow. Transmission from one meridian to the next, UCG, systemic examinations, and disease etiology tests can diagnose this condition after excluding specific sexually transmitted diseases such as subcutaneous nodular pericarditis or wind-dampness pericarditis.

bubble_chart Treatment Measures

(1) Medical Treatment

There is no unified opinion on the treatment plan, which mostly depends on the personal experience of the practitioner. Drug therapy includes the use of hormones, anti-inflammatory drugs, anti-subcutaneous node drugs, and other disease-cause treatments. Observation without medication may also be considered in asymptomatic cases.

Pericardiocentesis can alleviate symptoms and allow for the analysis of pericardial fluid to aid in diagnosis and treatment, but its therapeutic effect is not definitive and is no longer a primary treatment method.

(2) Surgical Treatment

The goal of surgical treatment is to relieve existing or potential pericardial tamponade, remove pericardial effusion, reduce the likelihood of recurrent pericardial effusion, and prevent advanced-stage pericardial constriction.

In cases where the diagnosis is clear and drug therapy is ineffective, pericardial drainage and pericardiectomy may be performed.

1. Subxiphoid Pericardial Drainage: This procedure is simple, rapid, causes minimal injury, has clear short-term efficacy, and fewer pulmonary complications, making it suitable for critically ill and elderly patients. However, the postoperative recurrence rate of pericardial effusion is relatively high. To reduce recurrence, the extent of pericardiectomy may be increased.

The technique of subxiphoid pericardial drainage has a history of over 160 years, and it was termed "pericardial window" in the 1970s. However, the therapeutic mechanism of pericardial window was only elucidated in recent years. Studies have shown that, with sustained and adequate drainage, fibrous adhesions form between the epicardium and pericardium, leading to the disappearance of the pericardial cavity, which explains the long-term efficacy of pericardial window.

Technique for subxiphoid pericardial drainage: The incision starts from the lower end of the sternum and extends downward, measuring approximately 6–8 cm in length. The upper segment of the linea alba is incised to expose and remove the xiphoid process. Blunt dissection is performed to separate the loose tissue between the posterior sternal wall and the anterior pericardial wall. A retractor is used to expose the upper abdominal incision, and a right-angle retractor lifts the lower end of the sternum. The anterior pericardial wall is incised, and pericardial fluid is aspirated. A pericardial resection of about 3 cm × 3 cm is performed to complete the pericardial window. A small additional incision is made beside the main incision to place a pericardial drainage tube. The incision is sutured, and the pericardial drainage tube is left in place for 4–5 days.

2. Partial or Complete Pericardiectomy via Thoracotomy with Thoracic Drainage: This method ensures complete drainage and a low recurrence rate. By removing a larger portion of the pericardium, the source of pericardial effusion and constriction is reduced, resulting in reliable surgical outcomes. However, the procedure involves greater injury and may lead to pulmonary or incision-related complications.

Surgical procedure for partial or complete pericardiectomy: The operation can be performed via a median sternotomy or through a left anterior or right thoracotomy.

(1) Partial Resection: The resection extends superiorly from the pericardial reflection at the great vessels to near the diaphragm inferiorly, and laterally to 1 cm anterior to both phrenic nerves.

(2) Complete Resection: The resection extends superiorly from the pericardial reflection at the great vessels to the midpoint of the diaphragmatic pericardium inferiorly. On the right side, the resection reaches 1 cm anterior to the right phrenic nerve, while on the left, it extends to the left pulmonary veins, taking care to preserve the left phrenic nerve from injury.

After pericardiectomy, the drainage tube is placed through the thoracic cavity and retained for 4–5 days postoperatively.

3. Pericardiectomy and Thoracic Drainage Using Video-Assisted Thoracoscopic Surgery (VATS): This method allows for extensive pericardial resection with minimal injury and satisfactory drainage. Postoperative complications are fewer, but the anesthesia process is more complex. {|114|}

Key points of performing pericardectomy using thoracoscopy: The patient is under general anesthesia with double-lumen endotracheal intubation, placed in the right lateral decubitus position, with right lung ventilation and left pleural cavity open, allowing the left lung to collapse. First, a 10mm trocar is inserted through the 7th intercostal space to dilate the intercostal pathway and place the thoracoscopic camera. Perform an intrathoracic exploration. Then, insert a grasping instrument through the 6th intercostal space along the anterior axillary line and a cutting instrument through the 5th intercostal space. During the operation, continuous positive-pressure carbon dioxide insufflation at approximately 8cm H2O can be applied to maintain lung collapse and facilitate pericardial exposure. Identify the phrenic nerve and make incisions anterior and posterior to it, resecting approximately 8–10cm of pericardium². Care should be taken to avoid injuring the left atrial appendage. The resected pericardial flap is grasped and removed. A drainage tube is placed at the pericardectomy site and brought out through the intercostal space, remaining in place for 2–3 days postoperatively.

Surgical Outcomes

The criteria for evaluating surgical outcomes include: ① whether symptomatic recurrent pericardial effusion occurs; ② whether pericardial constriction develops; ③ whether indications for repeat pericardial surgery arise.

Patients with chronic idiopathic pericardial effusion generally experience symptom relief and disappearance of pericardial effusion after surgical treatment.

Currently, it is believed that the extent of pericardial resection differs significantly among the various surgical approaches, but no notable differences have been observed in short-term outcomes. When considering both surgical efficacy and injury, thoracoscopic surgery is superior to subxiphoid drainage. The choice of surgical approach primarily depends on the patient's overall condition and the surgeon's experience and preference. In terms of long-term outcomes, the recurrence rate of subxiphoid pericardial drainage is slightly higher than that of transthoracic surgery, while the results of thoracoscopic surgery remain to be observed.