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Consensus and Guideline

Standard Operation Procedure of Percutaneous Endomyocardial Biopsy in Peking Union Medical College Hospital

Xu, Xiqi; Tian, Zhuang; Fang, Quan; Jing, Zhi-Cheng; Zhang, Shuyang

Editor(s): Xu, Tianyu; Fu, Xiaoxia

Author Information
doi: 10.1097/CD9.0000000000000023
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Abstract

Endomyocardial biopsy (EMB) is a technique that biopsy samples are obtained from the right or left ventricular using bioptome through the peripheral blood vessel. EMB and myocardial pathology are essential for accurate diagnosis, treatment, and evaluation of myocarditis and complex myocardial diseases. This clinical practice guideline is established based on the more than 10 years’ experience of Peking Union Medical College Hospital (PUMCH). The aim is to standardize the clinical application of EMB and improve its operational safety. With the widespread use of EMB, the diagnosis and treatment level of myocarditis and cardiomyopathy will be improved significantly in China.

The history of EMB

In 1958, Weinberg et al[1] reported the open surgical diagnostic biopsy of the pericardium and myocardium through a limited thoracotomy at Rush-Presbyterian-St. Luke's Medical Center in the United States to confirm the diagnosis of myocarditis or pericarditis. In 1960, Sutton and Sutton[2] introduced the needle biopsy using the modified Vim-Silverman needle through the transthoracic approach at Northwestern University School of Medicine. However, the occurrence of severe complications such as pneumothoraxes and cardiac tamponade were high and limited its acceptance. The first bioptome designed for transvenous EMB was the Konno-Sakakibara bioptome, developed in 1962 at the Affiliated Hospital of Tokyo Women's Medical College,[3] and over 450 patients in Japan underwent the procedure without significant complications. In 1973, Caves et al[4] developed the reusable Stanford Caves-Shultz biopsy forceps at Stanford University School of Medicine. It was then improved into the current clinically used flexible disposable biopsy forceps, which has a smaller flap and lead to a lower incidence of complications.

EMBs were started in the early 1980s in China. In November 1981, Sun et al[5] first reported a series of EMB results using self-made biopsy forceps at the Second Affiliated Hospital of Xi’an Medical College in China. Subsequently, Wang et al[6] at the Second Affiliated Hospital of Harbin Medical University and Rao et al[7] at the Affiliated Hospital of Chongqing Medical College published papers on the use of a modified bronchial or duodenal biopsy device for EMB, respectively. The development of EMB also promoted the progress of myocardial pathology in China. In May 2004, Yuejin Yang and Zhi-Cheng Jing completed an EMB (Cordis Corp, Miami Lakes, Florida, USA) for a heart transplantation patient and started the transplant rejection monitoring after heart transplantation at Fuwai Hospital, Chinese Academy of Medical Sciences. In 2014, Zhi-Cheng Jing and Xiqi Xu at the Department of Cardiology of Fuwai Hospital, cooperated with Yingmao Ruan, Hong Zhao et al at the Department of Pathology, used Argon EMB biopsy forceps (Argon Medical Devices, Inc, Athens, Texas, USA) to perform myocardial biopsies and pathological diagnosis on patients with clinically suspected myocarditis and cardiomyopathy. At the end of 2019, more than 270 EMBs were completed in Jing's group. In the 1980s, Puhui Jiao of PUMCH purchased an EMB forceps in the United States at her own expense. In 1987, Jiao et al[8] completed 13 cases of canine EMBs and pathological diagnosis. In 2007, Fang et al performed the first clinical EMB in PUMCH. By the end of 2019, Fang et al has completed more than 260 cases and accumulated a wealth of operating experience. This guideline summarizes the experience of more than 500 patients with EMBs.

Role of endomyocardial biopsy: from being questioned to the gold standard

As early as 1978, Ferrans and Roberts[9] of the National Heart, Lung, and Blood Institute published a review with the topic “Myocardial biopsy: a useful diagnostic procedure or only a research tool?” in Am J Cardiol. They considered that the diagnostic value of EMB in myocarditis was limited. The main reason was the histological diagnosis of myocarditis was the Dallas criteria at that time, which was defined as follows: histological evidence of inflammatory infiltrates within the myocardium associated with myocyte degeneration and necrosis of nonischemic origin. Besides, the clinical application of EMB was also limited because of the high incidence of complications.

Since the 1990s, myocarditis diagnosed by established histological, immunological and immunohistochemical criteria. Qualitative or quantitative polymerase chain reaction (PCR) and reverse transcription PCR (RT-PCR) can be used to detect DNA and RNA of viruses’ gene sequences. Ultrastructure inside or outside the myocardial cells of infiltrating cardiomyopathy can be observed by the electron microscope. Heart transplantation patients need rejection monitoring. So, the participation of pathologists is also very important in the diagnosis of myocarditis or cardiomyopathy.[10] Based on the improved instruments and the operators’ experience, the safety of EMB in both right and left ventricles was significantly improved, the incidence of serious complications has been less than 1%.[11] EMB and myocardial pathological diagnosis have been received great attention in clinical practice, and it has become a safe method – the more experienced the operator, the lower incidence of complications. The role of non-invasive cardiovascular magnetic resonance imaging (CMR) is limited by its resolution capacity, thus couldn’t replace the role of EMB. EMB is still the gold standard for the diagnosis of susceptive myocarditis, inflammatory cardiomyopathy, infiltrate cardiomyopathy, and other heart diseases.[12] Therefore, cardiologists in China should pay much attention to complex heart diseases and perform EMB actively in these patients. EMB and myocardial pathology will play an important role in the diagnosis and differential diagnosis of complex heart diseases.

Indications and contraindications of EMB

1. Considering the cost-benefit balance and possible procedural risks, indications for EMB in Department of Cardiology, PUMCH[12,13]: (1) rejection monitoring after heart transplantation; (2) clinically suspected myocarditis, such as infectious myocarditis, autoimmune myocarditis, eosinophilic myocarditis, giant cell myocarditis, etc; (3) suspected infiltrating cardiomyopathy, such as restrictive cardiomyopathy, myocardial amyloidosis, glycogen storage disease, hemosiderosis, etc; (4) heart involved in systemic diseases or affected by chemotherapy drugs, poisons, etc; (5) newly onset heart failure within 2 weeks, regardless of whether the heart size is normal or not; (6) newly onset heart failure more than 2 weeks, still combined with left ventricular enlargement and newly onset ventricular arrhythmia, second or third-degree atrioventricular block, or those who cannot completely return to normal after 1 to 2 weeks of conventional treatment; (7) heart tumor; (8) unexplained hypertrophic cardiomyopathy or suspected arrhythmic right ventricular dysplasia/right ventricular cardiomyopathy.

2. Contraindications for EMB in Department of Cardiology, PUMCH[12,13]: (1) bleeding disorders, severe thrombocytopenia, and those on anticoagulation therapy; (2) left ventricular biopsy is contraindicated in patients with acute myocardial infarction, left ventricular mural thrombosis, or ventricular aneurysm; (3) patients with significantly dilated heart with severe left ventricular insufficiency; (4) recently infected patients; (5) patients can not cooperate; (6) shunt disease is a relative contraindication, and left ventricular biopsy should not be done to avoid contradictory systemic embolism.

Techniques

Approach and guidance

Current researches proved that right ventricular biopsy is sufficient for most patients. The left ventricle tends to be biopsied on unusual occasions, such as a disease process predominantly affecting the left ventricle or left heart tumors.[14] EMB may be guided by fluoroscopy, 2-dimensional echocardiography, or both. The right internal jugular vein is the most common approach for EMB in PUMCH. Occasionally, the femoral vein approach can be used in some cases. The left internal jugular vein and subclavian vein approach are less recommended for EMB. Fluoroscopy is the most useful imaging modality and often sufficient for EMB. The most common projection position is the posterior-anterior position, sometimes left anterior oblique 45° posture is also needed. Echocardiography is increasingly being used to accurately direct biopsy forceps and reduce the likelihood of complications or recurrent biopsy of the same area. Echocardiography also should be used when attempting to biopsy a cardiac mass.

Preparation

Patients need to complete routine laboratory tests, electrocardiogram, echocardiography, and CMR before the biopsy. One of the diagnostic limitations of EMB is sampling error. Therefore, echocardiography and CMR may help to determine the location of myocardial lesions and reduce the opportunities of missed diagnosis. Clinicians should make a preliminary diagnosis according to clinical information and CMR before sending an EMB application.

Because coronary heart disease is the most common cause of cardiomyopathy and heart failure, all patients should rule out coronary heart disease before the EMB. All patients should not undergo anticoagulation or antiplatelet therapy before EMB examination. Those who are taking warfarin should stop in advance. The examination can be performed only when the international normalized ratio (INR) is ≤1.5. For patients treated with heparin or low molecular weight heparin, the drug should be withdrawn for at least 16 hours before the biopsy, and anticoagulation treatment can be resumed 12 hours after the examination and without any complications.

Key points of operation

  • 1. Equipment preparation: four-chamber or six-chamber Swan-Ganz catheter; Argon endomyocardial biopsy forceps (Jawz 2.2 mm Forceps, Maxi-Curved, 50 cm); bedside echocardiography.
  • 2. Staffing: cardiologist (perform the right heart catheterization and myocardial biopsy operations), assistant (measure hemodynamics data, collect blood gas samples, etc), nurse (prepare equipment and record hemodynamic data), cardiac sonographer (guide the puncture, help to direct biopsy forceps when necessary).
  • 3. Right heart catheterization: After entering the catheterization room, place the patient supine without pillow, with head 30° rotated to the left. Take the triangle vertex of the sternocleidomastoid muscle on the right side as the puncture point, sterilize the drape routinely, and use 1% lidocaine for local anesthesia. After successfully puncturing the right internal jugular vein, insert a vascular sheath of 7 F or above. Puncture of the right internal jugular vein can be performed under ultrasound guidance, which increases the success rate of puncture and reduces the risk of complications.

First, perform the standard right heart catheterization, measure and record the hemodynamic parameters such as superior vena cava pressure, right atrial pressure, right ventricular pressure, pulmonary artery pressure, pulmonary arterial wedge pressure, and cardiac output. Then draw blood from the above sites for blood gas analysis. Clinical classification of pulmonary hypertension should be diagnosed according to hemodynamic results [Table 1].[15]

Table 1 - Hemodynamic definitions of PH
Definition Hemodynamic characteristics Clinical group
PH mPAP ≥ 25 mmHg All 5 groups
 Pre-capillary PH mPAP ≥ 25 mmHg, PAWP ≤ 15 mmHg, PVR > 3 Wood Units Group 1. Pulmonary arterial hypertension;Group 3. PH due to lung diseases;Group 4. Hypertension due to chronic pulmonary artery obstruction;Group 5. PH with unclear and/or multifactorial mechanisms.
 Post-capillary PH mPAP ≥ 25 mmHg, PAWP > 15 mmHg Group 2. PH due to left heart disease;Group 5. PH with unclear and/or multifactorial mechanisms.
Isolated post-capillary PH DPG < 7 mmHg and/or PVR ≤ 3 Wood
Combined post-capillary and pre-capillary PH DPG ≥ 7 mmHg and/or PVR > 3 Wood
DPG = dPAP–PAWP, dPAP: Diastolic pulmonary artery pressure.DPG: Pulmonary artery diastolic pressure gradient; mPAP: Mean pulmonary artery pressure; PAWP: Pulmonary arterial wedge pressure; PH: Pulmonary hypertension; PVR: Pulmonary vascular resistance.

Right ventricle biopsy

After right heart catheterization, perform the EMB according to the following steps: First, check whether the Argon endomyocardial biopsy forceps works properly, and rinse the forceps surface with heparin saline. Second, keep the flaps closed while pushing the biopsy forceps. Under the posterior-anterior projection of X-ray, send the biopsy forceps to the middle and lower one third of the right atrium. At this time, rotate the handle of the biopsy forceps counterclockwise with the right hand to make the tip traverse the tricuspid valve and then contact with the ventricular septum under fluoroscopy. If meeting resistance, the forceps can be returned to the right atrium and re-entered. The operator could feel the heart beating after touching the right ventricular septum. Electrocardiograph (ECG) monitoring shows ventricular premature beats. The tip of the biopsy forceps was located 4 to 7 cm from the spine's left edge under the posterior-anterior projection of X-ray. Be careful not to open the flaps during the pushing process to avoid heart perforation. Third, confirm that the position of the biopsy forceps is correct, withdraw 1 to 2 cm and open the forceps flaps under X-ray, and observe. If the opening flaps and the push rod form a typical Y-shape, the position is correct; otherwise, it may point to the right ventricle's free wall, and the direction should be readjusted. Continue to push forward the forceps until resistance is felt and premature ventricular beats appear on the ECG monitoring. Close the forceps flaps and pull the biopsy forceps away from the interventricular septum gently. If the biopsy forceps cannot be separated easily, it may be because the tissue bitten by the forceps claps is too large or the chordae tendineae is clamped. If so, open the forceps flaps and withdraw the biopsy forceps, then repeat the operation. If there is a palpable sense of disconnection when withdrawing the biopsy forceps, it means that the myocardial tissue has been clamped. Keep the clamp flaps closed, and withdraw them out of the body. Rinse the biopsy forceps in a bowl filled with saline, and remove the myocardial tissue gently. Fourth, rinse the biopsy forceps with heparin saline, and repeat the EMB operation. After the operation, if the patient doesn’t present any discomforts such as chest tightness, suffocation, chest pain, etc, remove the sheath and bandage the puncture site, send the patient back to the ward for routine monitoring. Otherwise, bedside echocardiography should be performed immediately to observe if there are signs of new-onset pericardial effusion.

Postoperative monitoring

Complications of EMB include hematoma of the puncture site, new conduction block, pneumothorax, hemothorax, ventricular perforation, or pericardial tamponade, etc. If a complication is anticipated, the patient should be monitored, and serial echocardiography should be considered.

Note: The operation procedure of EMB should be performed under X-ray fluoroscopy. If resistance is encountered, retraction, anticlockwise rotation, and gentle advancement of the biopsy forceps should bypass the obstructions, do not push forcibly. In the posterior-anterior projection position, the tip of forceps should be placed at least 4 cm away from the left edge of the sternum; otherwise, the biopsy forceps may not fully enter the right ventricle or point to the free wall of the right ventricle [Figure 1]. When the biopsy forceps seem to enter the right ventricle, but no premature ventricular beats appear during the operation, the biopsy forceps may enter the coronary sinus. It can be verified at the left anterior oblique 45° to 60°. Once the biopsy forceps are found in the coronary sinus, retract the biopsy forceps immediately to the right atrium, adjust the direction, and operate again. Echocardiography can be used to guide the operation. Once the myocardial tissue is clamped, the flaps should be kept closed until it is withdrawn outside the body. After the operation, ask the patient if he has any chest tightness or chest pain. On the second day, electrocardiogram was routinely done to exclude conduction block, chest X-ray to exclude pneumothorax, hemothorax, and other puncture complications. Echocardiography was performed to exclude possibly new pericardial effusion.

F1
Figure 1:
X-ray guided right ventricular EMB. (A) The posterior-anterior projection position, showing the tip of biopsy forceps is too close to the spine side and does not fully enter the right ventricle. (B) The left anterior oblique 45°, showing that the tip points to the right ventricle's free wall. (C) The posterior-anterior projection position, the 2 clamp flaps and the push rod form a Y-shape, indicating that the clamp tip position is correct. (D) The left anterior oblique 45°, the clamp tip points to the interventricular septum, and the lower right is the echocardiography probe, suggest ideal clamping position. EMB: Endomyocardial biopsy.

Sample handling and processing

Operate carefully. Use a fine needle or rotate the clamp flaps in saline to remove the tissue; re-damage might affect the pathological diagnosis. The endomyocardial fragment is usually pink muscle tissue, each 1 to 3 mm2 in size. Routinely take 3 to 6 pieces of myocardial tissue for each examination. If the tissue is white or floating on the surface of saline, it may be fatty tissue or tricuspid valve leaflets. The myocardial tissue should be processed as soon as possible after the operation: fix at least 2 specimens in a 4% formaldehyde solution at room temperature. Ice salt water should be avoided because it could cause the formation of myocardial contractile bands. Fix at least 1 specimen in a 2.5% glutaraldehyde solution at room temperature. Then transfer to a 4°C refrigerator for storage. Use sterile cotton to absorb water from at least 1 specimen, put it in a dry cryotube, and transfer to a −80°C refrigerator for mass spectrometry or virus PCR detection. Paste patient information outside each cryopreservation tube [Figure 2] and record the above information, the number of materials taken, and pathological type into the electronic form. Record the number of different myocardial biopsy samples in Table 2. Organize pathological sections and frozen specimens to set up a biological sample bank.

F2
Figure 2:
Patient basic information.
Table 2 - Biopsy record form
Total number of materials Light microscope Electron microscope Liquid nitrogen
3 1 1 1
4 2 1 1
5 2 1 2
6 3 1 2

Light microscopic examination is routinely performed on formaldehyde-fixed and paraffin-embedded tissue and includes Hematoxylin-Eosin (HE) and Masson section examination. And CD3, CD4, CD8, CD19, CD20, CD68, and other immunohistochemical stains should be performed for suspected myocarditis or increased lymphocytes. Congo red staining should be performed for suspected amyloidosis, and anti-λ, anti-κ, anti-TTR antibody immunohistochemical staining should be performed when necessary. Transmission electron microscopy should be performed when glycogen storage disease, lysosomal disease, or viral myocarditis are suspected. Samples in the refrigerator at −80°C can be used for immunohistochemistry or molecular pathology research, such as PCR or RT-PCR for virus genome analysis.

Complications

Complication rates quoted in published case series vary from 0% to 3.3%, considering that many of the studies’ figures are obtained over a very long timeframe, the overall complication rate at present is around 1% or lower.[11,14] Common complications include vasovagal syncope, ventricular perforation, pericardial tamponade, heart block, supraventricular and ventricular arrhythmias, accidental arterial puncture, pneumothorax, vascular damage, nerve damage, pulmonary embolism, coronary-cameral fistula formation, bleeding complications and damage to the tricuspid valve. Ventricular cardiac perforation is a rare but severe complication. Do not remove the venipuncture sheath once cardiac perforation is suspected (it can be used as a fluid pathway for rehydration and infusion of vasoactive drugs). The operator should immediately perform echocardiography to assess the amount of pericardial effusion, and perform pericardiocentesis and drainage immediately once pericardial tamponade or hemodynamic instability occurs. Another serious complication is the irreversible complete atrioventricular block, which requires permanent pacemaker implantation. Most complications do not require special treatment and only need to be monitored closely.

Medical centers worldwide have formulated strict admission systems to improve the safety of EMB. Operators must have a solid foundation in the interventional field and must complete at least 50 cases of EMB under the guidance of experienced operators before becoming an independent operator.[11,16]

In summary, EMB is an important monitoring method for rejection after heart transplantation and an essential tool for the diagnosis of myocarditis, complicated cardiomyopathy, and cardiac tumors. Domestic and overseas studies have reported that the complication rate of EMB in the experienced clinical centers is less than 1%, and the rate of serious complications is even lower, so EMB is a safe procedure.[11,16] At present, more than 5 cardiologists in PUMCH can perform EMB independently, and more physicians are under training. Since cardiomyopathy is always unevenly distributed, the EMB may sometimes miss the diagnosis. Therefore, it is important to combine EMB and cardiovascular pathology with noninvasive investigations including laboratory evaluation, echocardiography, nuclear studies, and magnetic resonance imaging, to avoid missed diagnosis and misdiagnosis. With the emergence of specific treatment drugs for cardiomyopathy, pathological diagnosis based on EMB has attracted more attention. We recommend that EMB should generally be performed by the experienced cardiologists in the tertiary hospitals to improve the diagnosis accuracy of myocarditis and cardiomyopathy in China.

Funding

National Key Research and Development Program of China (2016YFC0901502); CAMS Innovation Fund for Medical Sciences (2016-I2M-1-002).

Conflicts of Interest

None.

Editor note: Zhi-Cheng Jing is an Editorial Board Member of Cardiology Discovery. The article was subject to the journal's standard procedures, with peer review handled independently of this editor and their research groups.

References

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[15]. Working Group on Pulmonary Vascular Diseases of Chinese Society of Cardiology of Chinese Medical Association; Editorial Board of Chinese Journal of Cardiology. Chinese guidelines for the diagnosis and treatment of pulmonary hypertension. Zhonghua Xin Xue Guan Bing Za Zhi 2018;46(12):933–964. doi: 10.3760/cma.j.issn.0253-3758.2018.12.006.
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Keywords:

Myocarditis; Cardiomyopathy; Endomyocardial biopsy

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