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Ann Thorac Surg 2005;79:1590-1596
© 2005 The Society of Thoracic Surgeons
Department of Cardiothoracic Surgery, Lenox Hill Hospital, New York, New York
* Address reprint requests to Dr Subramanian, Department of Cardiothoracic Surgery, Lenox Hill Hospital, 130 East 77th St, 4th Floor, New York, NY 10021 (E-mail: vsubramanian{at}lenoxhill.net).
Presented at the Fortieth Annual Meeting of The Society of Thoracic Surgeons, San Antonio, TX, Jan 26–28, 2004.
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Abstract |
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METHODS: From January to July 2003, 30 patients under went off-pump minimally invasive multivessel coronary bypass. Internal mammary arteries were harvested with robotic telemanipulation with three ports. A 2-inch to 3-inch incision with soft tissue retractor was used to perform coronary anastomosis. Robotic ports were used to introduce stabilization and cardiac positioning devices. Endoscopic harvesting of radial artery was done when necessary.
RESULTS: Twenty-three patients (77%) had anterior throracotomy approach and 7 (23%) had transabdominal approach. Average number of bypass grafts was 2.6 (range 2–4). There was no mortality in hospital or on 30-day follow-up. Twenty-nine patients (97%) were extubated on the operating table. Two patients required reoperation for bleeding and 1 of those patients needed conversion to sternotomy for additional bypass grafting. Within 24 hours of surgery 50% of patients (n = 15) were discharged, 10% (n = 3) were discharged in 24 to 36 hours, 17% (n = 5) were discharged in 36 to 48 hours, 17% (n = 5) were discharged in 48 to 72 hours, and 2 patients stayed more than 3 days in the hospital. Two patients needed readmission to hospital within 30 days; 1 for pleural effusion and 1 for wound infection.
CONCLUSIONS: Robotic harvesting of internal mammary arteries and port access stabilization and cardiac positioning allows multivessel coronary bypass to be performed through a small incision. Currently, the majority of the patients can be safely discharged within 36 hours of operation.
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Introduction |
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| Dr Subramanian discloses that he has a financial relationship with Guidant, Inc, and Ethicon, Inc.
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Coronary artery bypass surgery (CABG) has low morbidity and mortality with very dependable long-term results; however, the invasiveness of sternotomy and cardiopulmonary bypass leads to longer hospital stay. Elimination of cardiopulmonary bypass and limited access coronary surgery can expedite patient recovery leading to the ultimate goal of same day or outpatient coronary surgery.
Minimally invasive direct coronary artery bypass (MIDCAB) technique combines the advantages of limited surgical access with benefits of off-pump surgery. But it is limited to revascularization to single vessel in one territory of the heart [1–4]. Multivessel CABG through minimal access has been performed but requires cardiopulmonary bypass with peripheral cannulation and cardioplegic arrest [5, 6]. Robotic telemanipulation is a powerful tool that further minimizes the surgical access, especially harvesting entire length of both internal mammary arteries (IMAs) [7, 8]. Also, robotic telemanipulation allows further optimization of minithoracotomy incision for the coronary anastomosis.
Recent introduction of the port-access heart-positioning device in experimental set-up enables the surgeon to dislocate the heart in closed chest [9]. Also, introduction of a postaccess cardiac stabilization device allows surgeons to perform direct vision coronary surgery on the anterior surface of the heart through smaller incision [10]. Combining both robotic telemanipulation and postaccess instrumentation allows exposure of all the distal coronary target areas, enabling the surgeon to perform multivessel MIDCAB.
We report this feasibility study for robotic-assisted multivessel MIDCAB with port access stabilization and cardiac positioning leading to faster patient recovery.
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Patients and Methods |
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Data Collection and Follow-Up
All the preoperative, intraoperative, and postoperative variables were collected in accordance with New York State cardiac surgery reporting system. Follow-up was done either by the referring cardiologist or in our institution depending on patient's convenience.
Patient selection criteria was as follows:
In patients with short body stature, we preferred to use radial artery rather than right internal mammary artery.
Surgical Technique
PATIENT POSITIONING
The patients were placed in supine position with a roll under left chest with 30-degree elevation (Fig 1). This facilitated right IMA dissection and minithoracotomy incision. Left shoulder is dropped by hanging the arm on the side drapes supported at the wrist to avoid shoulder conflict of the robotic arm. Left arm is left out for simultaneous endoscopic radial artery harvesting when necessary.
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PORT PLACEMENT
Following skin prepping and draping the left lung is deflated and the camera port was introduced in the fifth intercostal space just below the nipple in males. In females the breast is pushed up with iodinated adhesive drape and camera port is placed in the submammary crease in the line of nipple. After connecting the CO2 insufflation the three-dimensional optic is attached and the left chest cavity is explored. CO2 insufflation (warmed and humidified) at pressures between 3 and 10 mm Hg was used for the harvesting of left IMA and 10 to 12 mm of Hg for the right IMA harvesting. The Da Vinci surgical system robot (Intuitive Surgical, Inc., Sunnyvale, CA) was then placed from the right so that the camera actuator of the robot can be connected to the camera port. Two other ports for the instrumentation, localized in the third (right arm) and sixth (left arm) intercostals space in the same line as the camera port were then introduced (Fig 2).
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BILATERAL IMA HARVESTING
First a 30-degree endoscope angled upward is introduced and the left IMA is scanned in the entire length. The scope is then changed to 0-degree endoscope. Mediastinum is dissected as described below. Right pleura is opened along the entire length of the IMA and insufflation is increased to 10 to 12 mm Hg. Right endothoracic fascia is opened and right IMA is harvested in its full length as skeletonized conduit. Sometimes it is necessary to divide right internal mammary vein to reach the origin of right IMA. If free RIMA is to be used for composite grafting, the right IMA is divided at its origin at this stage because it is difficult to reach the origin later on. After dividing the proximally the right IMA is brought to the left side and clipped to the pericardial fat. Left IMA is then dissected as described above. Then the distal end of right IMA is divided and brought across to the left side.
For transabdominal approach both the IMAs are harvested in their entire length as skeletonized grafts and the distal and left attached until the exposure of mediastinum through transabdominal incision.
DISSECTION OF MEDIASTINUM
To facilitate dislocation of heart, the mediastinal attachments to the sternum are detached along the entire length of the sternum as well as the diaphragmatic attachments to costal margins. This manipulation was carried out during robotic IMA harvesting.
SKIN AND CHEST WALL INCISION
For anterior thoracotomy approach the camera port incision is extended approximately 1 inch on either side in the fifth intercostals space. The subcutaneous tissue is divided in the same line as the pectoralis muscle. The fifth intercostals space is entered and the intercostals muscles are undermined in the space. Medium soft tissue retractor is placed to prevent the muscle and fat layers obstructing the line of vision. A low-profile MIDCAB retractor is placed (Genzyme or Estech Corporation, Danville, CA) and spread just enough to see distal targets.
For transabdominal MIDCABa 2- to 3-inch Chevron epigastric incision was made. Both rectus abdominis muscles with their anterior and posterior sheaths are partially divided preserving the lateral neurovascular bundles. Prior robotic release of costo- diaphragmatic attachments were laterally extended with cautery to facilitate exposure and increase the working angle through this incision. The lower edge of the sternum and the costal arch was lifted with table mounted (on the left side of the patient) modified IMA retractor hooks and blades (Rultrac, Ohio). This maneuver helps to lower position of the heart and increase working space between the sternum and anterior surface of the heart [11].
PERICARDIAL INCISION
All the epicardial fat is removed to facilitate exposure. Initial incision is made in the line of LAD not extended until anterior wall coronary anastomosis is done. For lateral and inferior wall coronary grafting the pericardial incision is extend over the apex to the diaphragm and laterally towards phrenic nerve to facilitate dislocation of the heart.
In transabdominal MIDCAB exposure the pericardium divided in an inverted "T" shape with the horizontal limb of the incision made along the entire length of the pericardiodiaphragmatic attachment.
CARDIAC POSITIONING
In anterior MIDCAB for LAD and diagonal exposure left lateral leaf of the pericardium is pulled up and out of the thoracotomy wound toward the left shoulder and fixed to the chest wall. This usually rotated the heart medially and optimized the presentation of the anterior coronary target vessels. Further medial rotation of the heart to expose the Ramus Intermidius branch is accomplished by bringing the suture on the lateral leaf of the pericardium through a stab wound in the left midaxillary line and the suture tied over a rubber bolster.
For lateral and inferior wall vessel grafting the positioning of the heart is done with EndoStarfish (Medtronic Inc, Minneapolis, MN; Fig 3). An 8- to 10-mm port is made underneath xiphiod and track is made with long clamp. EndoStarfish is introduced with trocar and Starfish is applied on the anterolateral wall away from the apex and the heart is rotated and pulled towards xiphiod so that the Starfish NS goes underneath the sternum to expose ramus and circumflex marginal branches. For the inferior wall coronary artery exposure the Starfish NS is applied to the apex and the acute margin of right ventricle and pushed towards the right shoulder and rotated so Starfish goes underneath upper rib cage.
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GRAFTING STRATEGY
In majority of the patients left IMA was anastomosed as in situ to LAD or sequentially to diagonal and LAD along with composite RIMA or radial artery grafts from the LIMA to lateral and inferior wall targets. In some instances in situ right IMA was anastomosed to LAD and in situ LIMA and radial composite grafts to lateral and inferior wall vessels. All composite grafting was "T" anastomosed before coronary grafting. For transabdominal MIDCAB in situ left IMA was anastomosed to distal LAD and in situ right IMA was anastomosed to right coronary or in situ gastroepiploic artery (GEA) was used for the right coronary artery branches.
We used standard anastomotic technique of running 8-0 or 7-0 Prolene sutures. The composite grafts were either performed in "T" fashion or spatulated end-to-end fashion. Slicone elstomer tapes were used for local control and intracoronary shunts were used liberally.
PROCESS OF CARE
All the patients were extubated on table and invasive lines are removed within 2 hours postoperative if patient had stable hemodynamics. These patients were encouraged to mobilize early and walk a few yards 4 to 6 hours postoperatively. The chest tubes were removed late in the evening or early next morning. For analgesia these patients had infiltration of the wound and the intercostals space with local analgesic. All these patients received 24-hour Ketorolac injections supplemented by opoid-based analgesics as per patient's requirement. All these patients had chest roentgenogram, 12-lead electrocardiograms, and blood profile before discharge.
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Results |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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The distribution of the conduits and target vessels are presented in Table 2. The average number of grafts was 2.6 (range 2–6).
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MOBILIZATION
Twenty-eight patients had their invasive monitoring lines taken out with 4 hours of completion of surgery. These patients were mobilized a few steps in evening of surgery.
HOSPITAL STAY
Fifteen patients (50%) were discharged in the morning of the day following surgery (within 24 hours of completion of surgery); 3 patients (10% in 24 to 36 hours following surgery) were discharged in the evening. Five patients were discharged on second postoperative day and 5 patients on third postoperative day. Two patients stayed more than 3 days; 1 patient for 7 days and 1 patient for 14days.
COMPLICATIONS
There was no in-hospital mortality or 30-day mortality. Two patients needed reexploration for bleeding. One had bleeding from the internal mammary harvest site on the chest wall. In the other patient no source of bleeding was found, but the same patient needed reexploration through median sternotomy due to low output state. One of three bypass grafts was found to be occluded (distal end-to-side graft of radial composite graft), so an additional vein graft was performed on beating heart. That patient had an intraaortic balloon pump inserted. He had a rise in cardiac enzymes but did not have any new Q waves on electrocardiogram. He was discharged after 14 days hospitalization.
Follow-Up
READMISSION WITHIN 30 DAYS
Two patients required hospitalization within 30 days. One had large left-sided pleural effusion that needed chest tube drainage as well as treatment for atrial fibrillation. The other patient who had transabdominal MIDCAB had deep wound infection needing intravenous antibiotics and local wound debridement and drainage.
STRESS TEST
Twenty-five patients had normal stress test postoperatively. One patient had mild inferior ischemia on stress test. This patient had occluded right coronary artery with poor collateralized vessels, which were not bypassed. Four patients refused stress test, because they were asymptomatic.
Follow-up was complete in 27 patients (90%). The average duration of follow-up was 3.5 months (range 1–7.5 months). There was no late mortality or recurrence of angina on late follow-up. One patient had non-Q wave myocardial infarction and required percutaneous transluminal coronary angioplasty to native coronary for occluded left IMA disease 6 months after surgery. One patient with vague chest discomfort had an angiogram 2 months after surgery. The angiogram showed normal widely patent grafts.
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Comment |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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Efforts have been made to harvest IMA with conventional thoracoscopic instruments with video assist, but this technique is limited by lack of precision due to fulcrum effect of the instruments at the entry in the thoracic cage and limited range of motion of the instruments. Introduction of robotic-assisted endowrist in the Da Vinci system (Intuitive Surgical) has allowed harvesting entire length of the IMA by totally endoscopic route [15, 16]; an advantage of this approach is that robotic indexing allows surgeons to maintain a comfortable and ergonomic arm position at the console while performing IMA dissection. While operating from the master console, the surgeon experiences no discomfort or fatigue caused by instrument torque, a common occurrence with manual videoscopic IMA harvesting. The controller software also eliminates the fulcrum effect of reversing instrument direction. This digital manipulation restores the natural hand motions of the open harvesting technique. These advantages have the effect of shortening the learning curve of totally endoscopic IMA harvesting [17]. Also, robotic instrumentation allows harvesting of bilateral IMAs totally endoscopically [17, 18]. The reasons mentioned above allowed us to harvest the entire length of left and right IMAs in a skeletonized fashion resulting in longer length of conduits that enabled us to perform multivessel grafting. Also, avoiding sternotomy allowed us to use bilateral IMA without increasing the risk of wound dehiscence, especially in diabetic patients.
Grundeman and colleagues [9] reported endoscopic exposure and stabilization of posterior and inferior wall coronaries in an animal experiment. In the current clinical study we used a combination of port access cardiac positioning and pericardial traction sutures to facilitate exposure of posterior and inferior wall coronaries through minimal access incision. Robotic dissection of mediastinum below the sternum allows creation of space between the heart and thoracic cage; this space allows rotation of heart without causing hemodynamic compromise. In this current we did not any conversion to sternotomy or cardiopulmonary bypass during initial operation due to hemodynamic compromise. However, there are limitations of current heart positioning devices like EndoStarfish; it is mounted on a rigid shaft that makes maneuvering difficult at times. It is too high profile for the limited space between the heart and the thoracic cage. The ideal heart positioning device should be low profile, which is more flexible for introduction and positioning, and then becomes rigid when the ideal position is achieved.
Post access stabilization has been described by Vassiliades [10] in endoscopic-assisted atraumatic coronary bypass for left IMA to left anterior descending artery. In our study we have used the Estech endostabilizer for port access stabilization. Free range of motion of stabilizer port makes it possible to apply to all targets through a single port. The port access stabilization allowed us to perform direct vision anastomosis without stabilizer obstructing the instrumentation or visualization of coronaries. Also introduction of stabilizer though the port makes stablibization more effective as the stabilizer shaft is almost perpendicular to the wall making compression effective.
Avoiding sternotomy and cardiopulmonary bypass and making small minimally access instrumentations in selected low risk patients leads to speedy recovery. This resulted in majority of our patients being discharged within 36 hours of hospital stay.
Average distal anastomosis of 2.6 per patient is lower compared to that reported in the STS database. Our patient population was carefully selected for this initial experience with fewer good size distal targets. Almost one-quarter of our patients had transabdominal MIDCAB who had two-vessel disease needing double bypass grafting leading to lower overall average. There was no compromise in completeness of revascularization.
Lack of routine postoperative angiogram to access graft patency is a limitation of this study. But we have used stress test and freedom from death, cardiac-related event, and repeat revascularization as surrogate markers for the graft patency. Twenty-five of 26 patients had negative stress test.
The limitation of our study is the small number of patients in very highly selected group with short-term follow-up. For this initial experience we chose patients with lower risk profile and good coronary targets. We believe that with technological advances, such as better cardiac positioning devices and facilitated anastomotic devices, this procedure might be more applicable to a wider patient population.
In conclusion, robotic assisted IMA harvesting with port access instrumentation makes direct vision multivessel coronary feasible through minimal access incision in highly selected group of patients. The speedy recovery of these patients could pave the way for outpatient coronary bypass grafts in the future.
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Discussion |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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DR SUBRAMANIAN: As our President of the Society, Dr Guyton, pointed out, learning one new operation each year; so I think the first thing would be training. I have to mention that we need to do more iterations on the technology. The Starfish I have shown here is a high-profile device and is on a rigid shaft; the endostabilizer is also on a rigid shaft. We are currently working at our institution to produce a steerable, flexible, ultra-low-profile stabilizer and a positioner, which will be steerable to any surface of the heart, and potentially useful for intracardiac operations such as mitral valve repair.
For the robotic training, obviously it does take time. We do need iteration even on the robotic techniques. I would envision in the future there would be a hybrid robotic system, a minirobotic system, or some other nonrobotic technique to harvest the internal mammary artery. As you know, in the minimally invasive direct coronary artery bypass (MIDCAB) operation we introduced in 1994 it was not that difficult to perform two-intercostal-space mobilization of the mammary artery. We need some facilitative technology to accomplish this through that minimal access. Everybody has gone completely out of the way into the dark forest looking for very high-intensity robotic techniques. So there are opportunities for us, the surgeons, and the industry to look for some sort of a hybrid system. I am sure it is coming soon.
DR SULAIMAN HASAN (Charleston, WV): I want to congratulate you on continuing to push the frontiers. The question I have is that with our experience with off-pump coronary artery bypass grafting (CABG) through a sternotomy, we with the Starfish will often raise the heart out of the chest in order to keep the hemodynamics stable. How does that work out with the chest essentially closed? Is that an issue?
DR SUBRAMANIAN: It is a completely different situation because in the midline sternotomy the heart has to be lifted beyond the midline to the right side to expose the lateral surface. Here the surgeon is on left side of the patient directly looking at the lateral surface of the heart. You really don't dislocate the heart. You basically rotate the heart, and the surface of the lateral wall comes to you. We have not seen any hemodynamic compromise. Everything is done within the left chest, so the presentation is very easy.
DR WILLIAM COLTHARP (Nashville, TN): That is an elegant series and report. The question I have for you is a philosophic question. Is there any worsening of long-term results justified by this technique?
DR SUBRAMANIAN: Obviously we can't talk about long-term results yet. The only thing we can talk about are results in the anterior MIDCAB with the left internal mammary artery (LIMA) left anterior descending (LAD) artery. That has stood the test of time. There has been a 2-year follow-up and late results presented by Calafiore and ourselves, as well as the late angiography at 6 months, which has shown equivalency to conventional coronary bypass surgery. So, obviously, for the multivessel MIDCAB technique we can't really answer your question until we have more angiographic data.
DR VALLUVAN JEEVANANDAM (Chicago, IL): Again, a beautifully elegant study. I have a question for you. Is your proximal anastomosis for the right internal mammary artery (RIMA) a T graft off the LIMA? And if you are going to do a free RIMA, why not use a radial? I don't know if there is any data to suggest that a radial or a RIMA is better when taken off as a T graft.
DR SUBRAMANIAN: All of the composite grafting has been in a T configuration. More and more we are doing a free right mammary composite graft to the left internal mammary artery. The radial artery is somewhat larger to put it on the skeletonized LIMA. Because of that, I am concerned about using that as a routine.
DR THOMAS L. MATTHEW (Boulder, CO): Thank you very much for an excellent presentation. I noticed that you used an epigastric approach, which is a very unusual approach for minimally invasive, and there was excellent exposure for the IMA and also for the posterior descending artery (PDA). Two questions. One is, how did you discover that approach, and second, have you used the gastroepiploic artery for a conduit at that location?
DR SUBRAMANIAN: Let me answer the first question. The tribute goes to my associate, Dr Nilesh Patel; if he is in the audience, perhaps he can rise up. In late 1998 in the middle of the night when I was struggling to do a right gastroepiploic artery (GEA) to the inferior wall with a standard vertical abdominal incision, Dr. Patel informed me quietly that that it would be a better approach through a transverse transabdominal incision with partial division of the recti releasing the costal diaphragmatic attachments.
In fact, if you look at it entomologically, many of the avian birds that fly very high, ie, soaring eagles, they can spread their wings very well, and they do have a very diminutive recti. So this has really brought on a very interesting approach, and releasing the diaphragmatic attachment is further able to release the costal arch. As you take a deep breath, the lower part of the thoracic cage actually moves up and outwards. So that was the genesis of this approach.
And we predominantly use a lot of GEA grafts for the posterior descending as well as for the posterolateral branch off the distal circumflex. Heart is positioned through this approach by the Starfish or by differential diaphragmatic pericardial traction sutures.
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References |
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TopAbstractIntroductionPatients and MethodsResultsCommentDiscussionReferences |
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