Cardiac surgeons continually strive toward less invasive approaches, which avoid full-median sternotomies and thoracotomies. Reports of “minimally invasive” cardiac surgical procedures may include hemi-sternotomies, “mini-thoracotomies,” or full-median sternotomies without cardiopulmonary bypass. True minimally invasive procedures must not only be defined by the size of the incision but also by the invasiveness into the patient’s daily lifestyle and the impact on their quality of life. Subxyphoid thoracoscopy has been performed to remove metastatic lesions from both pleural spaces simultaneously. This technique provides minimally invasive access to both pleural spaces through a single incision.1 In addition, complete thymectomy has been performed using a subxyphoid incision with thoracoscopy and a cervical incision.2,3
Paracardioscopy is a totally endoscopic technique that provides direct visualization of, and access to, the beating heart without the need for cardiopulmonary bypass or prolonged postoperative recovery. Unlike the subxyphoid access, paracardioscopy provides access via the central tendon of the diaphragm. This allows direct access to the posterior pericardial structures without hemodynamic compromise. Such access and visualization of the epicardial cardiac surface has enabled the development of the Extracardiac Maze procedure as a treatment for atrial fibrillation.4,5 Parcardioscopy eliminates the need for sternotomy or thoracotomy when access to the epicardial surface is necessary.
Description of Paracardioscopy
During paracardioscopy, the patient is positioned supine under general endotracheal anesthesia. A 2-cm incision is made 2 to 4 cm below the xyphoid and extended into the peritoneum under direct visualization. Once intra-abdominal adhesions are excluded by digital evaluation, two, 5-mm laparoscopic ports are placed in the left and right subcostal areas with the assistance of a finger inside the peritoneum. Peritoneal adhesions discovered on evaluation may require careful port placement with laparascopic evaluation of the abdomen and possible endoscopic lysis of adhesions. A 10-mm port is placed in the midline incision and the abdomen is insufflated with CO2 to 12 mm Hg (Fig. 1). Using a 10-mm laparoscope, the central fibrous region of the diaphragm is identified anterior to the left lobe of the liver and left of the falciform ligament. Reverse Trendelenburg positioning may allow gravity to reduce the viscera and provide better visualization of the diaphragm. Using standard laparoscopic scissors and graspers within the 5-mm ports, the central diaphragmatic tendon is opened 3 cm longitudinally. The incision should be 1 to 2 cm anterior to the reflection of the hepatic ligament to allow later closure of the diaphragm. Experience has demonstrated that the inferior vena cava is usually located opposite to the falciform ligament. If the diaphragmatic incision is too close to the falciform ligament, there will not be sufficient distance from the inferior vena cava within the pericardium to easily manipulate the paracardioscope.
An area of prepericardial fat is generally identified within the diaphragmatic incision. The pericardium is visualized beyond the fat, and the heart is seen beating within. The incision in the pericardium should be made directly behind the diaphragmatic incision. The pericardium is opened longitudinally as well, providing access to the posterior region of the heart. Once opened, the pericardium will be filled with CO2 from the abdomen. This tends to provide space between the pericardium and the heart for easier dissection but may also contribute to hypotension, especially if the patient is in reverse Trendelenburg position. Any hypotension will quickly correct with abdominal deflation or with placing the patient in a more head down position. The first direct view of the heart is at the acute margin of the right ventricle.
The Kiser paracardioscopic cannula (nContact Surgical, Morrisville, NC) provides direct access to the heart. The 10-mm port is removed and the cannula is positioned through the midline incision. Once the abdomen is reinsufflated, the cannula is positioned through the defect in the diaphragm and pericardium under the direct visualization of a 5-mm laparoscope in the left subcostal port (Fig. 2). The abdominal insufflation is discontinued and then a rigid endoscope is inserted into the cannula providing direct visualization and access to the left atrium, the coronary sinus, the inferior vena cava, and the right (Fig. 3) and left pulmonary veins (Fig. 4). Because the tip of the cannula is soft and flexible, it can be manipulated within the pericardium without injury to the epicardial surface of the heart. There is minimal, if any, compromise of cardiac function during paracardioscopy.
At the completion of the procedure, the cannula is replaced by the 10-mm port in the midline incision and the abdomen is reinsufflated with CO2. The 5-mm laparoscope is again positioned in the left subcostal port and using the Endostitch (Covidien, Norwalk, CT) device the diaphragmatic defect is closed. After placing the suture across the diaphragmatic defect, the knot can be tied extracorporally using the Endostitch device as a knot pusher. The abdomen is again deflated and all abdominal ports are removed. The fascia of the midline incision is closed securely with nonabsorbable interrupted suture, and the skin is closed routinely. The patient is extubated in the operating room and is usually ready for the discharge in 24 to 36 hours.
To date, more than 150 patients have undergone paracardioscopy. There have been no complications, no cardiac or vascular injuries, and no intraoperative conversions to sternotomy as a consequence of this procedure. Because paracardioscopy can only be performed when there is a pericardial space, patients with pericardial-to-cardiac adhesions, such as after pericarditis or previous cardiac surgery, are not good candidates for this procedure. Four patients have had pericarditis: two patients required an elective sternotomy at the time of paracardioscopy to complete the associated ablation procedure; one patient did not wish to proceed with the elective sternotomy and the paracardioscopy was terminated without entering the pericardium; and one patient had successful lysis of pericardial adhesions and liberation of the heart and all epicardial structures with the soft-tipped cannula and completed the paracardioscopic Extracardiac Maze procedure without complication.
1. Taniguchi Y, Suzuki Y, Suda T, et al. Video-assisted thoracoscopic bilateral lung metastasectomy with a subxiphoid access port. J Thorac Cardiovasc Surg
2. Zielinski M, Hauer L, Kuzdzal J, et al. Technique of the transcervical-subxiphoid-videothoracoscopic maximal thymectomy. J Min Access Surg
3. Hsu CP, Chuang CY, Hsu NY, Shia SE. Subxiphoid approach for video-assisted thoracoscopic extended thymectomy in treating myasthenia gravis. Interact Cardiovasc Thorac Surg
4. Kiser AC, Wimmer-Greinecker G, Chitwood WR. Totally extracardiac maze procedure performed on the beating heart. Ann Thorac Surg
5. Kiser AC, Wimmer-Greinecker G, Kapelak B, et al. Paracardioscopic ex-maze procedure for atrial fibrillation. Innovations
This How To Do It article from Dr. Andy Kiser describes a visualization technique for epicardial ablation for atrial fibrillation. Thoracoscopic visualization of the pericardial spaces has been described by a number of previous investigators and has been used by others to perform minimally invasive ablation both in the operating room and electrophysiology laboratory. This report describes a unique transabdominal transdiaphragmatic approach using a device that Dr. Kiser helped to develop. Although this report does establish that visualization of the coronary veins, vena cava, atrial appendages, and posterior left atrium is possible, it does not establish the efficacy of these procedures in terms of curing atrial fibrillation. This depends both on adequate visualization and a device capable of achieving reliable transmural lesions from the epicardial surface on the beating heart. The latter goal has not been achieved by any present device on the market and remains a great challenge for a successful minimally invasive epicardial surgical ablation.