Ultrathin Endoscopy-Guided Pericardiocentesis: A Pilot Study in a Swine Model

Abstract: Background. Pericardiocentesis under echocardiography guidance is a common procedure, but still poses a risk of injury to surrounding tissues. Nowadays, pericardiocentesis is being performed in patients with normal pericardium, for epicardial ablation or atrial appendage exclusion. Access to the normal pericardial space with the conventional needle procedure is very difficult. Thus, development of a novel method enabling safer pericardiocentesis is necessary. The present study aimed to assess the feasibility of using an originally developed ultrathin endoscopy-guided pericardiocentesis device in a swine model. Methods and Results. We developed a novel ultrathin endoscopy-guided pericardiocentesis device. The device comprised a 1.2 mm ultrathin endoscope, a 20 G needle, and a grasping forceps. Pericardiocentesis was conducted as follows. A 12 Fr introducer sheath was inserted between the pericardium and the diaphragm under fluoroscopy. The pericardium was grasped with the originally developed forceps under endoscopy guidance to create a space in the pericardial sac. The 20 G needle was then inserted and a coiled-tip guidewire was placed into the pericardial sac. Five independent operators performed pericardiocentesis twice using this technique in a healthy pig with a body weight of approximately 25 kg. Procedural success rate and procedure time were assessed as the primary endpoints. The procedural success rate was 100% in all operators. The average procedure time was 65 ± 40 seconds (median, 46 seconds; interquartile range, 40-85 seconds). No procedure-related complications were noted. Conclusions. The study results indicate that ultrathin endoscopy-guided pericardiocentesis for normal pericardial space is feasible and safe. 

J INVASIVE CARDIOL 2016;28(3):78-80

Key words: pericardiocentesis, endoscope

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Pericardiocentesis is a procedure that involves the removal of fluid from the pericardial space. Pericardiocentesis is usually done under echocardiography guidance to minimize complications. Although an appropriate echocardiography-guided pericardiocentesis is associated with improved safety, it still holds the risk of complications. The main complications are cardiac puncture, coronary vessel injury, and death. Observational studies of echocardiography-guided pericardiocentesis report that the major complication rate is approximately 2%.^1,2 Moreover, in recent years, a non-surgical approach from the epicardial surface has become useful for various cardiac interventions, such as positioning of the left ventricular lead for cardiac resynchronization therapy,³ epicardial ablation,^4–6 and atrial appendage exclusion.⁷ These procedures require pericardiocentesis of the normal-volume pericardial sac, which is usually difficult.  

We developed a novel device to make pericardiocentesis safer and easier, even in patients with normal pericardial space. The device is designed to guide pericardiocentesis by grasping the pericardium under direct visualization using the ultrathin endoscope. The present study aimed to assess the safety and feasibility of the novel ultrathin endoscopy-guided pericardiocentesis in a healthy swine model.

Methods

Device design and technique. The device comprises a 1.2 mm fiberoptic camera (Medigus, Inc), a light source, a grasping forceps, and a 20 G long needle (Figure 1). The 1.2 mm ultrathin fiberoptic camera employs a CMOS image sensor and has a 100° viewing angle with 10 mm focal length. The grasping forceps and 20 G long needle were also originally developed. The outer diameter of the forceps is 1.15 mm and the maximum grip force is 3.2 N. The length of the 20 G needle is 20 cm. All these components are bundled into a rigid 4 lumen tube. The outer diameter of the 4 lumen tube is 4 mm. 

The ultrathin endoscopy-guided pericardiocentesis is performed as follows. First, a 12 Fr introducer sheath is inserted at the subxiphoid area into the space between the diaphragm and the pericardium under fluoroscopy. The pericardium is grasped with the forceps under endoscopy guidance to make a space in the pericardial sac. Then, the pericardium is punctured using the 20 G needle under endoscopy guidance. A coiled-tip guidewire is placed into the pericardial sac through the 20 G needle.

Animal experiment. The feasibility of ultrathin endoscopy-guided pericardiocentesis was assessed in a healthy female pig with a body weight of 25 kg. The procedure was performed under general anesthesia by five independent operators with different experiences. Each operator conducted the procedure twice, for a total of 10 procedures. The study protocol was approved by Kyoto University Animal Care and Use Committee and performed in accordance with the Guide for the Care and Use of Laboratory Animals. The procedural success rate and the procedure time were assessed as the primary endpoints of the study. Procedural success was defined as a successful puncture of the pericardium and insertion of the guidewire into the pericardial sac without any complications. The position of the guidewire was confirmed by fluoroscopy. The procedure time was defined as the elapsed time from the insertion of the endoscope into the 12 Fr sheath to the insertion of the guidewire into the pericardial sac. All procedures were conducted through the same 12 Fr sheath placed at the beginning of the experiment. Every pericardiocentesis procedure was performed to puncture a different part of the pericardium. The endoscopy clearly visualized a small hole of the pericardium made by the former attempts. We avoided puncturing the same hole with the visual guidance. Values are expressed as mean ± standard deviation. 

Results

The procedural success rate was 100% in all attempts. The average procedure time was 65 ± 40 seconds (median, 46 seconds; interquartile range, 40-85 seconds). No procedure-related complications were noted. Representative images during the procedure are presented in Figure 2. Endoscopic images are also supplied in Video 1. 

Discussion

The study results indicate that this novel technique of endoscopy-guided pericardiocentesis, which involves grasping the pericardium, was safe and feasible in a healthy pig with normal-volume pericardial sac.  

Pericardiocentesis is the aspiration of fluid from the pericardial space that surrounds the heart. It is conducted either as a therapeutic option for patients with cardiac tamponade, or as a diagnostic tool for patients with pericardial effusion of unknown cause. Echocardiography guidance has made pericardiocentesis safer than before, but the procedure is still associated with complications, including pneumothorax, damage to surrounding vital structures, cardiac wall puncture, injury to coronary arteries, and death.^1,2 Moreover, several procedures requiring access to the normal-volume pericardial sac have emerged recently. These procedures include positioning of the left ventricular lead for cardiac resynchronization therapy,³ epicardial ablation,^4,5 and atrial appendage exclusion.⁷ Percutaneous puncture of the normal-volume pericardial sac is difficult because the echo-free space in the pericardial sac is very limited. 

Several devices and techniques have been invented to achieve a safe access to the normal-volume pericardial sac. Some electrophysiologists prefer using a large-bore needle (Tuohy or Pajunk needle) or a long micropuncture needle under fluoroscopic guidance.^4,5,8 The needle position is confirmed by injecting a small amount of contrast while advancing the needle. Although this technique is feasible in the absence of pericardial effusion, the risks of myocardial or coronary laceration cannot be ignored, as demonstrated by several independent investigators.^5,6 Another research group invented a dedicated device for pericardiocentesis in patients without pericardial effusion. The PerDUCER device enables a tangential puncture of the pericardium by using vacuum suction.^9-11 The major limitation of the PerDUCER device is that handling the device is relatively complex, and its application is often limited by the presence of pericardial fat, which is not rare in clinical practice. Liu et al recently reported the feasibility of a visual puncture system.¹² The visual puncture system uses a 0.9 mm imaging fiber and enables pericardiocentesis under endoscopy guidance. The system is very similar to our device, but it lacks the grasping forceps, which we consider very important to achieve a safe puncture of the pericardium. The newly developed grasping forceps in the present study enables the operator to hold the pericardium tightly, and accomplish pericardiocentesis without fail. The main disadvantage of the present system is the requirement of an introduction of a 12 Fr introducer sheath to start the endoscopy-guided pericardiocentesis, which may cause serious complications. Thus, development of a thinner endoscopy-guided system is required in the future. 

In the present study, we assessed a novel pericardiocentesis device, which enables a safe access to the normal pericardial space by using an ultrathin endoscope and the grasping forceps. Stem cell delivery on the epicardial surface might be an option in patients with heart failure in the future.^10,13 In that light, this new device has the potential advantage of enabling visualization of the target lesion on the myocardium and injecting stem cells into the target lesion under endoscopy guidance. Although similar attempts have been conducted by another group,^14,15 the strength of our device is that it is thinner than other devices, and can be used for a variety of applications, from pericardiocentesis to cell injection, under endoscopic guidance. 

Study limitations. First, the study employed a swine model and there is a considerable difference in anatomy between swine and human. Second, the results in this study were derived from only one animal. Moreover, all procedures were conducted via the same 12 Fr sheath placed between the pericardium and the diaphragm at the beginning of the experiment. This technically demanding step was only performed once, and made the additional procedural attempts easier. Finally, this study lacked randomization and a control group with which to compare the endoscopy-guided pericardiocentesis technique. This is a preliminary study that aimed to assess the initial feasibility of the novel device and technique. More detailed studies are therefore required to verify the true efficacy of the ultrathin endoscopy-guided pericardiocentesis technique. 

Conclusion

The study results indicate that the ultrathin endoscopy-guided pericardiocentesis technique is safe and feasible.

Acknowledgments. The authors wish to thank Mr T. Matsumoto, Mr M. Kanke, and Mr T. Kusunoki for their technical assistance in developing the device. Special thanks also go to Ms K. Omichi for her secretarial assistance. 

References

1.     Nguyen CT, Lee E, Luo H, Siegel RJ. Echocardiographic guidance for diagnostic and therapeutic percutaneous procedures. Cardiovasc Diagn Ther. 2011;1:11-36. 

2.     Tsang TSM, Enriquez-Sarano M, Freeman WK, et al. Consecutive 1127 therapeutic echocardiographically guided pericardiocenteses: clinical profile, practice patterns, and outcomes spanning 21 years. Mayo Clin Proc. 2002;77:429-436. 

3.     Zenati M, Bonanomi G, Chin AK, Schwartzman D. Left heart pacing lead implantation using subxiphoid videopericardioscopy. J Cardiovasc Electrophysiol. 2003;14:949-953. 

4.     Yamada T. Transthoracic epicardial catheter ablation. Circ J. 2013;77:1672-1680. 

5.     Gunda S, Reddy M, Pillarisetti J, et al. Differences in complication rates between large bore needle and a long micropuncture needle during epicardial access — time to change clinical practice? Circ Arrhythm Electrophysiol. 2015;8:890-895. Epub 2015 Jun 15.

6.     Sacher F, Roberts-Thomson K, Maury P, et al. Epicardial ventricular tachycardia ablation a multicenter safety study. J Am Coll Cardiol. 2010;55:2366-2372. 

7.     Miller MA, Gangireddy SR, Doshi SK, et al. Multicenter study on acute and long-term safety and efficacy of percutaneous left atrial appendage closure using an epicardial suture snaring device. Heart Rhythm. 2014;11:1853-1859. 

8.     Ebrille E, Killu AM, Anavekar NS, et al. Successful percutaneous epicardial access in challenging scenarios. Pacing Clin Electrophysiol. 2015;38:84-90. 

9.     Maisch B, Ristić AD, Rupp H, Spodick DH. Pericardial access using the PerDUCER and flexible percutaneous pericardioscopy. Am J Cardiol. 2001;88:1323-1326. 

10.     Rupp H, Rupp TP, Alter P, Jung N, Pankuweit S, Maisch B. Intrapericardial procedures for cardiac regeneration by stem cells: need for minimal invasive access (AttachLifter) to the normal pericardial cavity. Herz. 2010;35:458-466. 

11.     Seferovic PM, Ristic AD, Maksimovic R, et al. Initial clinical experience with PerDUCER device: promising new tool in the diagnosis and treatment of pericardial disease. Clin Cardiol. 1999;22:I30-I35. 

12.     Liu X, Feng Y, Xu G, et al. A new strategy for pericardiocentesis with a visual puncture system: the feasibility and efficiency study in a pericardial effusion model. Int J Cardiol. 2014;177:e128-e130. 

13.     Ptaszek LM, Mansour M, Ruskin JN, Chien KR. Towards regenerative therapy for cardiac disease. Lancet. 2012;379:933-942. 

14.     Kimura T, Miyoshi S, Okamoto K, et al. The effectiveness of rigid pericardial endoscopy for minimally invasive minor surgeries: cell transplantation, epicardial pacemaker lead implantation, and epicardial ablation. J Cardiothorac Surg. 2012;7:117. 

15.     Kimura T, Miyoshi S, Takatsuki S, et al. Safety and efficacy of pericardial endoscopy by percutaneous subxyphoid approach in swine heart in vivo. J Thorac Cardiovasc Surg. 2011;142:181-190.

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From the ¹Department of Cardiovascular Medicine, Graduate School of Medicine, Kyoto University, Kyoto, Japan; and the ²Department of Cardiology, Gifu Heart Center, Gifu, Japan.

Funding: This study was financially supported by Kansai Innovation Global Strategic Comprehensive Special Zone. This study was performed as a joint research of Kyoto University, Toray Medical Co, Ltd, Forte Grow Medical Co, Ltd, and Sumita Optical Glass, Inc. 

Disclosure: The authors have completed and returned the ICMJE Form for Disclosure of Potential Conflicts of Interest. Dr Naritatsu Saito and Dr Takeshi Kimura hold the patent on the pericardiocentesis device.  The remaining authors report no conflicts of interest regarding the content herein. 

Manuscript submitted July 23, 2015, provisional acceptance given August 21, 2015, final version accepted September 23, 2015.

Address for correspondence: Naritatsu Saito, MD, Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, 54 Kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507 Japan. Email: naritatu@kuhp.kyoto-u.ac.jp