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Minimally invasive mitral valve repair using the da Vinci robotic system
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Minimally Invasive Mitral Valve Repair Using the da Vinci Robotic System Antone J. Tatooles, MD, Patroklos S. Pappas, MD, Paul J. Gordon, MD, and Mark S. Slaughter, MD Division of Cardiac Surgery, Advocate Christ Medical Center, Oak Lawn, Illinois
Background. Minimally invasive mitral valve repair with a shortened hospital stay and quick return to an active lifestyle is the ultimate goal for robotically assisted surgery. We evaluated our da Vinci robotically assisted mitral valve repair experience toward achieving this goal. Methods. All procedures were performed with peripheral cardiopulmonary bypass, transthoracic aortic crossclamp, and antegrade cardioplegia. Two ports and a 4-cm intercostal incision in the right chest were used for access. All patients had a ring annuloplasty, and all but 1 had a posterior leaflet resection. The entire repair and all knot tying were performed robotically. Results. Between October 2001 and October 2002, 25 patients (18 men) underwent robotic mitral valve repair. The mean age was 56 years (range, 37 to 81 years). There were no incisional conversions, deaths, strokes, or reoperations for bleeding. Twenty-one (84%) of 25 patients were extubated in the operating room. Overall mean study times were as follows: procedure, 199.7 minutes
(range, 140 to 287 minutes); cardiopulmonary bypass, 126.6 minutes (range, 89 to 186 minutes); and cross-clamp, 87.7 minutes (range, 58 to 143 minutes). Eight (32%) patients were discharged home in less than 24 hours, with an average length of stay of 2.7 days. Comparing the first 10 patients to the last 15 there was a significant reduction of times: total operating room time, 318.5 versus 275.1 minutes; cross-clamp, 97.6 versus 81.1 minutes; leaflet resection or repair, 26.2 versus 15.6 minutes; annuloplasty ring, 31.9 versus 24.8 minutes; and length of stay, from 4.2 days to 1.67 days. Five patients had postoperative atrial fibrillation. Two (8%) patients ultimately required mitral valve replacement for recurrent mitral insufficiency. Conclusions. Mitral valve repair can be successfully performed with the da Vinci robotic system. Long-term follow-up is needed to determine the durability of the repair compared with a standard sternotomy approach. (Ann Thorac Surg 2004;77:1978 – 84) © 2004 by The Society of Thoracic Surgeons
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field and improved surgical manipulation by use of the endowrists of the surgical arms. Felger and coworkers [4], using a robotically directed approach, have subsequently demonstrated similar operative times with an improvement in length of stay and intubation time. The ultimate goal of minimally invasive surgery is to maintain excellent results while minimizing the hospitalization and interruption in daily life for the patient. With these goals in mind, we evaluated our experience with minimally invasive mitral valve repair using the da Vinci robotic system and its effect on postoperative ventilation, time in the intensive care unit, and overall length of stay.
inimally invasive mitral valve surgery continues to evolve as a treatment option. Cohn and colleagues [1] and Cosgrove and associates [2] had shown that mitral and aortic valve procedures could be performed with a small incision by modifying the standard sternotomy. Criticisms of this approach include the concerns of limited access, increased technical difficulty, and limited visualization of the operative field. Casselman and colleagues [3] recently reported a large and successful series of endoscopic mitral valve repairs using an EndoCPB system. However, this technique requires significant endoscopic surgical skills and an aortic occlusion and cardioplegia delivery system that is not used frequently by all cardiac surgeons. With the introduction of the da Vinci robotic system (Intuitive Surgical, Inc, Sunnyvale, CA), many of the concerns of minimally invasive mitral valve repair were addressed. The da Vinci robotic system allows three-dimensional visualization of the operative Accepted for publication Nov 25, 2003. Presented at the Thirty-ninth Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 31–Feb 2, 2003. Address correspondence to Dr Slaughter, Cardiothoracic and Vascular Surgical Associates, SC, 4400 W 95th St, Suite 205, Oak Lawn, IL 60453; e-mail: [email protected].
© 2004 by The Society of Thoracic Surgeons Published by Elsevier Inc
Material and Methods With institutional review board approval and informed consent, patients were enrolled in a Phase II US Food and Drug Administration–approved multicenter trial (G000295) to evaluate mitral valve repair using the da Vinci robotic system. Between October 2001 and October 2002, 25 consecutive patients underwent robotically assisted mitral valve repair. All patients were symptomatic with severe (grade 3 or 4) mitral regurgitation. Patients had posterior leaflet disease only with generally pre0003-4975/04/$30.00 doi:10.1016/j.athoracsur.2003.11.024
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Results All 25 procedures were performed by the same patientside and console surgeons per trial protocol. The mean age of the patients was 56 years, and all but 1 had normal ventricular function (Table 1). Only 24% of the patients were in New York Heart Association class II or III.
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Table 1. Demographic Data Characteristic Age (y) Sex Female Male EF MR grade 3⫹ 4⫹ NYHA Class I Class II Class III Smoking Hypertension Diabetes Stroke COPD Hx arrhythmia A-fib V-tach Other
n ⫽ 25 (%)
Mean
Range
56.4
37– 81
7 (28%) 18 (72%) 0.57
0.40 – 0.70
9 (36%) 16 (64%) 19 (76%) 3 (12%) 3 (12%) 11 (44%) 11 (44%) 0 (0%) 1 (4%) 2 (8%) 10 (40%) 4 (16%) 2 (8%) 4 (16%)
A-fib ⫽ atrial fibrillation; COPD ⫽ chronic obstructive pulmonary disease; EF ⫽ ejection fraction; Hx ⫽ history; MR ⫽ mitral regurgitation; NYHA ⫽ New York Heart Association; V-tach ⫽ ventricular tachycardia.
Myxomatous degeneration with P2 prolapse was the cause of the mitral valve insufficiency in all 25 patients. Chordal rupture involving the posterior leaflet was also present in 13 (52%) patients. All patients had a ring annuloplasty, and 96% had a posterior leaflet resection with repair. The number of sutures required for securing the annuloplasty ring ranged from five to eight, with 88% receiving either six or seven horizontal mattress sutures. All knot tying was performed with the robot with five knots per suture. Sizing the annulus is difficult through the intercostal access, so the ring size was generally based on intraoperative transesophageal echocardiography annulus assessment. All but 1 patient received a 28-mm annuloplasty ring.
Table 2. Operative Data (n ⫽ 25) Variable
Mean ⫾ SD
Range
Total OR time (min) Procedure time (min) CPB (min) Cross-clamp (min) Leaflet resection or repair (min) Ring annuloplasty (min)
292.4 ⫾ 37.8 199.7 ⫾ 43.0 126.6 ⫾ 25.7 87.7 ⫾ 20.9 20.0 ⫾ 11.4
238 –380 140 –287 89 –186 58 –143 9 –53
27.6 ⫾ 6.7
15– 40
CPB ⫽ cardiopulmonary bypass; standard deviation.
OR ⫽ operating room;
SD ⫽
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served ventricular function (ejection fraction ⬎ 0.30). All inclusion and exclusion criteria are listed in Appendix A. The mitral valve was evaluated by echocardiography and quantitatively assessed preoperatively, intraoperatively, and postoperatively at 30 days. The echocardiograms were read by an independent cardiologist at a designated study core laboratory. With the anesthesiologists, an anesthesia protocol was developed to allow for consistent extubation in the operating room. The anesthesia technique used is listed in Appendix B. All data were prospectively collected. A Student’s t test analysis was performed to determine statistical significance (GB-stat Version 6.5; Dynamic Microsystems, Inc, 1999, Silver Spring, MD). The patient is placed in the supine position with the right chest elevated approximately 30 degrees and the right arm secured above and across the patient’s head. A radial arterial catheter and Swan-Ganz catheter are used for hemodynamic monitoring. External defibrillator patches are placed on the thoracic cage. A double-lumen endotracheal tube is inserted with right lung deflation. The right femoral artery and vein are cannulated for cardiopulmonary bypass. Additionally, a 17F wire-bound cannula is inserted in the right internal jugular vein for upper body venous return. A 4-cm incision is made in either the fourth or fifth intercostal space. The camera is placed through the anterior aspect of this incision, and it allows access for the patient-side surgeon to assist the console surgeon. Two additional ports are placed for the robotic arms. An antegrade cardioplegia needle is inserted into the ascending aorta through the working intercostal space. The ascending aorta is cross-clamped with a transthoracic aortic cross-clamp through a stab incision in the third intercostal space. The operative field is flooded with carbon dioxide. A standard longitudinal left atriotomy is performed. The left atrium is retracted using the Heartport retractor (Heartport, Inc, Redwood City, CA). The valve inspection, posterior leaflet resection, leaflet reapproximation, and ring annuloplasty (Cosgrove Edwards Annuloplasty Band, Edwards LifeScience, Irvine, CA) are all performed robotically. A quadrangular resection was performed when indicated, and the leaflets were reapproximated with a running suture. No annular plications or sliding annuloplasties were performed. All knot tying was also completed with the robot. Air was removed from the heart through the cardioplegia needle. A single chest tube was inserted to drain the right pleural space. The pericardium was not reapproximated, and pacing wires were not used. An intercostal nerve block with 1% Marcaine was performed before closing the chest. Anesthesia was planned to attempt intraoperative extubation in all patients.
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Table 3. Postoperative Data (n ⫽ 25) Variable CARDIOVASCULAR
Extubated in OR ICU (h) LOS (days) Discharged ⬍24 h Discharged ⬍30 h Pt’s requiring PRBC’s
N (%)
Mean ⫾ SD
Range
35.4 ⫾ 18.5 2.68 ⫾ 3.1
18 –72 1–16
21 (84%)
8 (32%) 12 (48%) 11 (44%)
ICU ⫽ intensive care unit; LOS ⫽ length of stay; OR ⫽ operating room; PRBCs ⫽ packed red blood cells; Pts ⫽ patients; SD ⫽ standard deviation.
Table 2 details the time it took to complete the procedure as well as several individual components of the operation. The total operating room time was just less than 300 minutes. The actual time it takes to robotically resect and repair the posterior leaflet averaged 20 minutes. Insertion of the annuloplasty ring, placing sutures, and tying them was less than 30 minutes. The remainder of the cross-clamp time is needed for exposing the valve, valve inspection, interval dosing of cardioplegia, removing air, and closing the left atrium. The majority of the patients (84%) were extubated in the operating room (Table 3). The 4 patients who required postoperative ventilation in the intensive care unit were extubated in less than 5 hours. All patients were up in a regular chair in the evening of the same day they underwent surgery. The chest tube was removed the following morning unless an air leak was present or the total drainage was greater than 500 mL. Indications for transfusion of packed red blood cells were a hematocrit less than 24% while rewarming on cardiopulmonary
Table 4. Postoperative Complications (n ⫽ 25) Conversion to sternotomy Reoperation for bleeding Neurologic TIAa CVA Wound infection Chest Groin Groin lymphocele Pulmonary Reintubation Prolonged air leakb Pleural effusion Renal failure A-fib a
Occurred 12 days after discharge. 24 h.
0 (0%) 0 (0%) 1 (4%) 0 (0%) 2 (8%) 0 (0%) 1 (4%) 0 (0%) 1 (4%) 1 (4%) 2 (8%) 5 (20%) b
Air leak requiring chest tube ⬎
A-fib ⫽ atrial fibrillation; CVA ⫽ cerebral vascular accident; ⫽ transient ischemic attack.
TIA
bypass or a hematocrit less than 24% in the postoperative period. Using these guidelines, 11 patients required perioperative transfusion of packed red blood cells. The average time in the intensive care unit was 35.4 hours, with an overall length of stay of only 2.68 days. Eight (32%) patients were discharged home from the intensive care unit in less than 24 hours after the completion of their operation. Table 4 outlines the nonvalve-related complications encountered with robotically assisted mitral valve repair. There were no deaths, no conversions to a standard sternotomy, and no reoperations for bleeding. Two patients had cellulitis of the intercostal incision, and there were no groin wound infections. One patient did experience a lymphocele of the groin requiring surgical drainage and closure. There were no strokes, but 1 patient did have a transient ischemic attack 12 days after discharge. A transesophageal echocardiogram was suggestive of thrombus on the sewing ring. The patient received anticoagulation treatment and experienced no further symptoms. Despite the aggressive extubation protocol, no patient required reintubation. One patient did have a prolonged air leak requiring continued chest tube drainage that extended the length of stay. One other patient had a late pleural effusion that required a thoracentesis at an outside hospital. Two patients had an elevated creatinine (renal failure) that required no treatment. Five patients exhibited atrial fibrillation postoperatively. Two of these occurred while in the hospital. Two patients required readmission for rate control, and 1 was managed as an outpatient. A total of 7 (28%) patients required readmission after discharge. Only 3 of these patients had been discharged in less than 24 hours initially. The average time from discharge to readmission was 7 days (range, 1 to 13 days). Echocardiograms performed at 30 days postoperatively (n ⫽ 24) revealed 12 (50%) patients had no mitral regurgitation, 11 (46%) patients had 1⫹ mitral regurgitation, and only 1 (4%) patient had 2⫹ mitral regurgitation. All patients were in New York Heart Association Class I and remain so at 12 to 24 months’ follow-up. Two patients ultimately required reoperation for mitral valve replacement. One patient was readmitted 3 days postoperatively for shortness of breath. An echocardiogram revealed new 2⫹ mitral regurgitation, which progressed to 3⫹ mitral regurgitation several days later. On reexploration the repair and ring were intact, but part of the anterior leaflet was torn from the annulus. The second patient was readmitted 40 days postoperatively for hemolytic anemia. Evaluation revealed 1⫹ to 2⫹ mitral regurgitation that was a high-velocity jet beneath an incompletely seated annuloplasty ring. At the time of valve replacement there was no evidence of infection. Table 5 divides our experience into two phases: the first 10 cases, which we considered our learning curve, and then our last 15 cases. There is a trend toward improved times for the overall procedure and cardiopulmonary bypass time, but they did not reach statistical significance. However, the cross-clamp time, leaflet resection or repair time, and annuloplasty ring time were
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Table 5. Initial Cases Versus Current Experience (n ⫽ 25)a
Comment
Variable
The evolution of minimally invasive mitral valve surgery continues to move forward. The early efforts, which involved modifications of the standard sternal incision, have now developed to the point at which the operation is performed almost entirely with robotic assistance. These stepwise improvements have followed the suggested steps and classification of minimally invasive cardiac surgery as reported by Loulmet and associates [5]. Successful series have been reported using port access, endovascular cardiopulmonary bypass, and aortic occlusion with a voice-controlled camera robotic arm [6, 7]. However, that technique requires the surgeon to learn new port access skills and the use of an endoaortic occlusion balloon, which can be difficult to position [8]. With the introduction of the transthoracic aortic crossclamp [9] and the da Vinci Surgical System, mitral valve repair can now be performed in a manner very similar to a standard sternotomy approach but with truly limited incisions. Nifong and colleagues [10] recently reported their successful initial results with the da Vinci system, which led to the multi-center trial. Because the technique and skills are familiar, there is a relatively short learning curve as demonstrated in the improvement in our series after the first 10 cases. Our operative times closely resemble those reported by Felger and coworkers [4] and Nifong and colleagues [10], who were able to show that mitral valve repair could be performed with similar operative times compared with standard techniques using a median sternotomy. Our current experience also demonstrates that robotically assisted mitral valve repair can be performed safely and with satisfactory early results. Realizing that mitral valve repair can be performed safely and with good long-term results through a sternotomy approach, is there any advantage to pursuing less-invasive mitral valve repair? Felger and coworkers [4] and Nifong and colleagues [10] now have a large experience with minimally invasive mitral valve repair and have shown clinical results equal to the conventional sternotomy approach but with decreased complications. In particular, there are fewer pulmonary complications and reoperations for bleeding. Intuitively, it would appear that this is a result of avoiding the sternotomy. We took this one step further with a planned anesthetic regimen to extubate the patients in the operating room. We successfully extubated more than 80% of patients in the operating room with no patient requiring reintubation. This has allowed for earlier ambulation and return of bowel function. Subsequently, patients can be considered for home discharge sooner with an average length of stay less than 48 hours in the last half of our experience. In those patients we discharged in less than 24 hours, 5 (63%) required no readmission and were seen only in the office as an outpatient. Because the readmission rate is not insignificant, the advantages of 24 to 48 hours postoperative discharge will require further evaluation. Chitwood and Nifong [11] have previously shown decreased costs of minimally invasive mitral valve repair compared
Total OR time (min) Procedure time (min) CPB time (min) Cross clamp time (min) Leaflet repair (min) Annuloplasty ring (min) LOS (days) a
1st 10 Cases
Last 15 Cases
p Value
318.5
275.1
0.003
209.9
192.2
0.345
137.2 97.6
119.5 81.1
0.093 0.050
26.2
15.6
0.001
31.9
24.8
0.007
4.2
1.67
0.043
Mean values.
CPB ⫽ cardiopulmonary bypass; operating room.
LOS ⫽ length of stay;
OR ⫽
significantly reduced in the second half of our experience. Our average length of stay is now down to 1.67 days, which is a significant improvement compared with our first 10 cases. Figure 1 demonstrates a typical wound 30 days postoperatively.
Fig 1. Typical right thoracic wounds on postoperative day 30.
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with conventional sternotomy. This was predominantly owing to a decrease in the length of stay. However, if one figures in the capital expenditure for the robot, service contracts, and disposable components, this becomes a controversial issue. There is no question that the better cosmetic result compared with a conventional sternotomy has improved our patient satisfaction. In our experience, 2 patients did require reoperation for recurrent mitral regurgitation. Both patients had less than 1⫹ mitral regurgitation on their initial postoperative echocardiogram. The first patient had a partially torn anterior leaflet at the time of reoperation. This appeared to be a technical problem that was unrecognized at the initial procedure. The second patient had hemolysis from an incompletely seated annuloplasty ring. Because there is no tactile sensation, the knot tying depends on visual clues as to appropriate tension and tightness. Currently, the ring is inspected, including manipulation to make sure that it is snug on the annulus. Both of these failures occurred earlier in our overall experience. Thus, the learning curve includes not only a gradual improvement in times but an improvement in decision making and evaluating the valve repair itself. If the goal of minimally invasive mitral valve surgery is to perform the operation with reduced surgical trauma, decreased pain, fewer complications, improved cosmesis, shorter length of stay, and earlier return to a normal daily activity for the patient, then we believe that our series, as well as those by Casselman and associates [3], Felger and colleagues [4], Reichenspurner and associates [6], and Mohr and coworkers [7], has demonstrated the potential advantages of minimally invasive mitral valve surgery. However, the ultimate test will be the long-term durability and need for reoperation compared with a conventional sternotomy approach. Mohty and colleagues [12] have clearly established these long-term outcomes, which minimally invasive mitral valve surgery will have to match. Our study has provided additional information to the potential advantages of minimally invasive mitral valve surgery, such as improved cosmesis and fewer bleeding and pulmonary complications. The majority of patients can be extubated in the operating room with early ambulation. The role of early discharge (⬍48 hours) needs additional evaluation owing to the relatively high
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readmission rate. Our patient population was generally young and healthy with good ventricular function. Whether or not this technique is feasible for morecomplex repairs or in elderly, sicker patients remains to be determined. Also, longer follow-up is needed to determine whether robotically assisted mitral valve repair in this select patient population is durable and will compare favorably to the 5- and 10-year results achieved through a sternotomy approach.
References 1. Cohn LH, Adams DH, Couper GS, et al. Minimally invasive cardiac valve surgery improves patient satisfaction while reducing costs of cardiac valve replacement and repair. Ann Thorac Surg 1997;226:421–8. 2. Cosgrove DM, Sabik JF, Navis JL. Minimally invasive valve operations. Ann Thorac Surg 1998;65:1535–9. 3. Casselman FP, Slycke SV, Dom H, Lambrechts DL, Vermeulen Y, Vanermen H. Endoscopic mitral valve repair: feasible, reproducible and durable. J Thorac Cardiovasc Surg 2003;125:273–82. 4. Felger JE, Chitwood WR, Nifong LW, Holbert D. Evolution of mitral valve surgery: toward a totally endoscopic approach. Ann Thorac Surg 2001;72:1203–9. 5. Loulmet DF, Carpentier A, Cho PW, et al. Less invasive methods for mitral valve surgery. J Thorac Cardiovasc Surg 1998;115:772–9. 6. Reichenspurner H, Boehm DH, Gulbins H, et al. Threedimensional video and robot-assisted port-access mitral valve operation. Ann Thorac Surg 2000;69:1176 –82. 7. Mohr FW, Onnasch JF, Falk V, et al. The evolution of minimally invasive mitral valve surgery—2 year experience. Eur J Cardiothorac Surg 1999;15:233–9. 8. Schneider F, Falk V, Walther T, Mohr FW. Control of endoaortic clamp position during port-access mitral valve operations using transcranial Doppler echography. Ann Thorac Surg 1998;65:1481–2. 9. Chitwood WR, Elbeery JR, Moran JF. Minimally invasive mitral valve repair using transthoracic aortic occlusion. Ann Thorac Surg 1997;63:1477–9. 10. Nifong LW, Chu VF, Bailey BM, et al. Robotic mitral valve repair: experience with the da Vinci system. Ann Thorac Surg 2003;75:438 –43. 11. Chitwood WR, Nifong LW. Minimally invasive videoscopic mitral valve surgery: the current role of surgical robotics. J Card Surg 2000;15:61–75. 12. Mohty D, Orszulak TA, Schaff VH, Avierinos JF, Tajik JA, Sarano ME. Very long-term survival and durability of mitral valve repair for mitral valve prolapse. Circulation 2001; 104(Suppl 1):I-1–7.
DISCUSSION DR W. RANDOLPH CHITWOOD (Greenville, NC): First, I would like to thank the authors for participating in the da Vinci Multicenter Mitral Valve Study in which 10 centers participated, as well as supplying me with the advanced copy of their manuscript. Doctor Tatooles and his coauthors have provided us, in an excellent presentation, data that support the continued exploration of using robotic assistance, or what really is telemanipulation, to do complete mitral valve repairs through truly minimal access incisions. These types of well-regulated clinical trials remain the touchstones for The Society for Thoracic Surgeons and our surgical specialties to advance and improve therapy for
our patients. This is what it is all about. The results that Dr Tatooles and others have shown us today, and during the last several years, are helping to create a safe ascent up the Everest slope to a truly endoscopic mitral valve operation. Despite encouraging advancements, there are really three cautions for surgeons who choose this pathway of technologic development and applicative therapy. With these new devices and technologies, there are completely new learning curves, and albeit shortened by the amazing telemanipulative abilities of these devices, everyone must enter a common portal to a format that sets surgeons, both young and old, nearly at the same starting level.
Second, we must not fool ourselves into thinking that this is a lesser operation because there is less tissue injury. The operation must be done with the same quality, long-term results, and standards for mitral valve repair surgery to which Professor Carpentier and others have held us. Last, any surgeon who does traditional mitral valve surgery well can provide his or her patients new benefits with these devices, but only if they have patience and can develop a completely new way of thinking about a way to do cardiac surgery. Doctor Tatooles has performed 25 mitral valve repairs along a well-planned protocol in which posterior leaflet resections were done, followed by a repair, and insertion of an annuloplasty band. All patients were followed by a protocol, through a third-party echocardiographic core laboratory, with follow-up transthoracic studies done 1 month after surgery. There were no deaths or incisional conversions in his group, and no strokes or myocardial infarctions occurred. One patient had a transient ischemic attack 7 days after discharge. Of all patients, 84% were extubated in the operating room, and the average length of stay was 2.7 days, which is the lowest in the multicenter trial that averaged 4.7 days in 112 patients. This is compared with the year 2002 STS data that showed a total length of stay of 8.5 days for repairs in nearly 900 patients. In Dr Tatooles’s series, there were seven readmissions, or 28%, and two reoperations requiring a valve replacement. Forty-four percent of his patients received a transfusion. What Dr Tatooles has added to the multicenter protocol is a custom “fast track” anesthesia protocol with the intent of early extubation and early hospital discharge. In addition to a good repair, the course goal for the patient seems to have been preset, mainly at the very beginning, on rapid patient mobilization and cost reduction. Who can argue with these premises? However, although his cross-clamp, perfusion, and ventilatory times were significantly less than in our 60 patients, or many other patients in the multicenter trial, you still transfused 44% of your patients versus our 15% who received blood products. Moreover, your readmission rate was 28%. I was pleased to see that the cardiologists are referring to you patients who have severe regurgitation but are either asymptomatic or in no more than moderate congestive heart failure. Many are finding that these patients benefit most from a good repair by preventing atrial fibrillation and eventual ventricular impairment. I have several questions that arise from your study as well as from our observations and experience. You had two valve replacements, one within the first week from leakage and one at 40 days from hemolysis. Interestingly, we had a patient in our series who developed severe hemolysis and at reoperation was found to have a portion of the band that was not sewn flush with the tissue, creating a small fabric loop, which caused severe hemolysis. This patient had to have the valve replaced. This was in our early patient group, when our average number of sutures was eight. In your series, 76% of patients had only six sutures placed in a 28-mm Cosgrove annuloplasty band. In our last 30 of 60 patients, we have averaged 11 sutures to avoid this problem. Doctor Tatooles, are you expecting more hemolytic problems in your early patients and have you modified your technique since this reoperation? The ring or band must be placed as tight to the annular tissue as with sternotomy access. Clearly, the main reason that you were able to discharge your patients so early relates to your anesthetic method, early extubation, efficient pain control, liberal transfusions, and guided mobilization.
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We can learn a lot from this plan in managing all minimally invasive surgical patients. However, your 28% readmission rate bespeaks the fact that there seems to be an obligatory hospitalization period for any patient who undergoes any invasive cardiac procedure requiring perfusion and cardioplegic arrest. Our readmission rate has been almost nil, and we have not transfused nearly as many patients as have you, nor used a fast-track anesthesia protocol. In fact, our cardiopulmonary perfusion times are longer than yours, yet our length of stay is only a day or two longer at a mean of 3.9 days. Please comment on your readmissions and the reason for them. Last, having been a leader in this area, do you believe that we can achieve truly endoscopic telemanipulation for mitral surgery with instrument arms only without the need for even a small incision, and what are your thoughts for the future? Are there adjunctive facilitating technologies that are being developed that will help us? You and your colleagues are to be congratulated on a scientifically planned and well-executed study, for your honest results, for your excellent presentation, and for your solid attempts to improve patient care through the development of care protocols and new technologic methods, namely, computer-assisted telemanipulation using robotic devices. I would like to thank Drs Baumgartner, Guyton, and Murray as well as the scientific program committee for a superb meeting, and to thank the Society for the privilege of discussing this paper. God bless America. DR TATOOLES: Doctor Chitwood, thank you for your kind comments and your pioneering work in minimally invasive surgery and application of robotic techniques. In regards to our valve replacement, one patient did have a partial dehiscence of the posterior aspect of the annuloplasty ring. The etiology of this problem was not defined, but it may have been related to the number of sutures placed or to the technique of suture placement. Annuloplasty sutures are tied after the placement of each suture. This differs from our open technique and may increase the risk of ring dehiscence if the suture pulls partially through the annulus during placement of the subsequent stitch or kinks the annuloplasty ring. Placement of additional sutures may decrease the risk of ring dehiscence so long as sutures are placed under adequate tension to seat the ring against the annulus. We do not anticipate, nor have we seen, other patients developing complications related to hemolysis or ring dehiscence but will continue to follow our patients closely. In regards to our readmission rate, three of twelve patients discharged home on their first postoperative day were readmitted. Of these, one returned for symptomatic atrial fibrillation, one for upper extremity phlebitis, and one for a pleural effusion. An extended hospital stay would not have likely altered these complications. Early discharge did not contribute to postoperative morbidity, and select patients with close follow-up can be safely discharged on their first postoperative day. Although we did not specifically look at risk factors for transfusion requirements, 44% of our patients did receive blood or blood products. Early treatment of anemia may have facilitated our expedited discharge protocol; further evaluation of our transfusion threshold may decrease our perioperative use of blood and blood products. I would like to thank the Society for the privilege of allowing us to present our work. Thank you.
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Appendix A Inclusion Criteria CARDIOVASCULAR
1. 18 to 80 years of age 2. Has clinically significant mitral valve regurgitation (grade 3 or 4) 3. Has signed informed consent
Preoperative Exclusion Criteria 1. Has any of the following echocardiographic findings: a. Mitral valve stenosis with moderate to severe mitral valvular calcification (any grade) b. Severely calcified mitral valve annulus c. Moderate to severe tricuspid valve insufficiency (grade 3 or 4) d. Moderate to severe aortic valve regurgitation or stenosis (grade 3 or 4) e. Left ventricular ejection fraction less than 0.30 2. Has a history of acute myocardial infarction in preceding 30 days before proposed mitral valve surgery 3. Has hemodynamic instability with or without mitral valve disease or myocardial infarction 4. Has severe coronary artery disease requiring multivessel coronary artery bypass grafting 5. Has concomitant acute bacterial endocarditis 6. Has a previous right thoracotomy 7. Has a body mass index more than 35 kg/m2 8. Has an anatomy unsuitable for endoscopic visualization of the thorax, eg, morbid obesity with remarkable axillary adiposity or physical deformities of the thorax 9. Has symptoms of severe asthma, emphysema, chronic obstructive pulmonary disease, or pulmonary fibrosis, or other evidence of pulmonary decompensation
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10. Has significant hepatic compromise (cirrhosis, hepatitis, liver failure) 11. Has dialysis-dependent renal failure 12. Has untreated cerebrovascular disease 13. Has severe bleeding disorder 14. Has undergone previous radiation therapy of the mediastinum or right thorax 15. Has connective tissue disease (e.g., Marfan’s syndrome, Ehlers-Danlos syndrome) 16. Has uncontrolled diabetes mellitus 17. Is unable to give informed consent 18. Is pregnant
Appendix B Premedication Midazolam 1 to 3 mg intravenously
Induction Sufentanil 1 to 2 g/kg intravenously Etomidate 0.2 to 0.5 mg/kg intravenously
Maintenance Propofol 50 to 75 g · kg⫺1 · min⫺1 intravenously Sevoflurane 0% to 2% inhalation
Reversal Neostigmine 5 mg intravenously Robinul 1 mg intravenously
Postoperative Analgesia Ketorolac tromethamine 15 to 30 mg every 6 hours intravenously Morphine sulfate 1 to 5 mg every hour as needed intravenously
Minimally Invasive Mitral Valve Repair Using the da Vinci Robotic System Antone J. Tatooles, MD, Patroklos S. Pappas, MD, Paul J. Gordon, MD, and Mark S. Slaughter, MD Division of Cardiac Surgery, Advocate Christ Medical Center, Oak Lawn, Illinois
Background. Minimally invasive mitral valve repair with a shortened hospital stay and quick return to an active lifestyle is the ultimate goal for robotically assisted surgery. We evaluated our da Vinci robotically assisted mitral valve repair experience toward achieving this goal. Methods. All procedures were performed with peripheral cardiopulmonary bypass, transthoracic aortic crossclamp, and antegrade cardioplegia. Two ports and a 4-cm intercostal incision in the right chest were used for access. All patients had a ring annuloplasty, and all but 1 had a posterior leaflet resection. The entire repair and all knot tying were performed robotically. Results. Between October 2001 and October 2002, 25 patients (18 men) underwent robotic mitral valve repair. The mean age was 56 years (range, 37 to 81 years). There were no incisional conversions, deaths, strokes, or reoperations for bleeding. Twenty-one (84%) of 25 patients were extubated in the operating room. Overall mean study times were as follows: procedure, 199.7 minutes
(range, 140 to 287 minutes); cardiopulmonary bypass, 126.6 minutes (range, 89 to 186 minutes); and cross-clamp, 87.7 minutes (range, 58 to 143 minutes). Eight (32%) patients were discharged home in less than 24 hours, with an average length of stay of 2.7 days. Comparing the first 10 patients to the last 15 there was a significant reduction of times: total operating room time, 318.5 versus 275.1 minutes; cross-clamp, 97.6 versus 81.1 minutes; leaflet resection or repair, 26.2 versus 15.6 minutes; annuloplasty ring, 31.9 versus 24.8 minutes; and length of stay, from 4.2 days to 1.67 days. Five patients had postoperative atrial fibrillation. Two (8%) patients ultimately required mitral valve replacement for recurrent mitral insufficiency. Conclusions. Mitral valve repair can be successfully performed with the da Vinci robotic system. Long-term follow-up is needed to determine the durability of the repair compared with a standard sternotomy approach. (Ann Thorac Surg 2004;77:1978 – 84) © 2004 by The Society of Thoracic Surgeons
M
field and improved surgical manipulation by use of the endowrists of the surgical arms. Felger and coworkers [4], using a robotically directed approach, have subsequently demonstrated similar operative times with an improvement in length of stay and intubation time. The ultimate goal of minimally invasive surgery is to maintain excellent results while minimizing the hospitalization and interruption in daily life for the patient. With these goals in mind, we evaluated our experience with minimally invasive mitral valve repair using the da Vinci robotic system and its effect on postoperative ventilation, time in the intensive care unit, and overall length of stay.
inimally invasive mitral valve surgery continues to evolve as a treatment option. Cohn and colleagues [1] and Cosgrove and associates [2] had shown that mitral and aortic valve procedures could be performed with a small incision by modifying the standard sternotomy. Criticisms of this approach include the concerns of limited access, increased technical difficulty, and limited visualization of the operative field. Casselman and colleagues [3] recently reported a large and successful series of endoscopic mitral valve repairs using an EndoCPB system. However, this technique requires significant endoscopic surgical skills and an aortic occlusion and cardioplegia delivery system that is not used frequently by all cardiac surgeons. With the introduction of the da Vinci robotic system (Intuitive Surgical, Inc, Sunnyvale, CA), many of the concerns of minimally invasive mitral valve repair were addressed. The da Vinci robotic system allows three-dimensional visualization of the operative Accepted for publication Nov 25, 2003. Presented at the Thirty-ninth Annual Meeting of The Society of Thoracic Surgeons, San Diego, CA, Jan 31–Feb 2, 2003. Address correspondence to Dr Slaughter, Cardiothoracic and Vascular Surgical Associates, SC, 4400 W 95th St, Suite 205, Oak Lawn, IL 60453; e-mail: [email protected].
© 2004 by The Society of Thoracic Surgeons Published by Elsevier Inc
Material and Methods With institutional review board approval and informed consent, patients were enrolled in a Phase II US Food and Drug Administration–approved multicenter trial (G000295) to evaluate mitral valve repair using the da Vinci robotic system. Between October 2001 and October 2002, 25 consecutive patients underwent robotically assisted mitral valve repair. All patients were symptomatic with severe (grade 3 or 4) mitral regurgitation. Patients had posterior leaflet disease only with generally pre0003-4975/04/$30.00 doi:10.1016/j.athoracsur.2003.11.024
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Results All 25 procedures were performed by the same patientside and console surgeons per trial protocol. The mean age of the patients was 56 years, and all but 1 had normal ventricular function (Table 1). Only 24% of the patients were in New York Heart Association class II or III.
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Table 1. Demographic Data Characteristic Age (y) Sex Female Male EF MR grade 3⫹ 4⫹ NYHA Class I Class II Class III Smoking Hypertension Diabetes Stroke COPD Hx arrhythmia A-fib V-tach Other
n ⫽ 25 (%)
Mean
Range
56.4
37– 81
7 (28%) 18 (72%) 0.57
0.40 – 0.70
9 (36%) 16 (64%) 19 (76%) 3 (12%) 3 (12%) 11 (44%) 11 (44%) 0 (0%) 1 (4%) 2 (8%) 10 (40%) 4 (16%) 2 (8%) 4 (16%)
A-fib ⫽ atrial fibrillation; COPD ⫽ chronic obstructive pulmonary disease; EF ⫽ ejection fraction; Hx ⫽ history; MR ⫽ mitral regurgitation; NYHA ⫽ New York Heart Association; V-tach ⫽ ventricular tachycardia.
Myxomatous degeneration with P2 prolapse was the cause of the mitral valve insufficiency in all 25 patients. Chordal rupture involving the posterior leaflet was also present in 13 (52%) patients. All patients had a ring annuloplasty, and 96% had a posterior leaflet resection with repair. The number of sutures required for securing the annuloplasty ring ranged from five to eight, with 88% receiving either six or seven horizontal mattress sutures. All knot tying was performed with the robot with five knots per suture. Sizing the annulus is difficult through the intercostal access, so the ring size was generally based on intraoperative transesophageal echocardiography annulus assessment. All but 1 patient received a 28-mm annuloplasty ring.
Table 2. Operative Data (n ⫽ 25) Variable
Mean ⫾ SD
Range
Total OR time (min) Procedure time (min) CPB (min) Cross-clamp (min) Leaflet resection or repair (min) Ring annuloplasty (min)
292.4 ⫾ 37.8 199.7 ⫾ 43.0 126.6 ⫾ 25.7 87.7 ⫾ 20.9 20.0 ⫾ 11.4
238 –380 140 –287 89 –186 58 –143 9 –53
27.6 ⫾ 6.7
15– 40
CPB ⫽ cardiopulmonary bypass; standard deviation.
OR ⫽ operating room;
SD ⫽
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served ventricular function (ejection fraction ⬎ 0.30). All inclusion and exclusion criteria are listed in Appendix A. The mitral valve was evaluated by echocardiography and quantitatively assessed preoperatively, intraoperatively, and postoperatively at 30 days. The echocardiograms were read by an independent cardiologist at a designated study core laboratory. With the anesthesiologists, an anesthesia protocol was developed to allow for consistent extubation in the operating room. The anesthesia technique used is listed in Appendix B. All data were prospectively collected. A Student’s t test analysis was performed to determine statistical significance (GB-stat Version 6.5; Dynamic Microsystems, Inc, 1999, Silver Spring, MD). The patient is placed in the supine position with the right chest elevated approximately 30 degrees and the right arm secured above and across the patient’s head. A radial arterial catheter and Swan-Ganz catheter are used for hemodynamic monitoring. External defibrillator patches are placed on the thoracic cage. A double-lumen endotracheal tube is inserted with right lung deflation. The right femoral artery and vein are cannulated for cardiopulmonary bypass. Additionally, a 17F wire-bound cannula is inserted in the right internal jugular vein for upper body venous return. A 4-cm incision is made in either the fourth or fifth intercostal space. The camera is placed through the anterior aspect of this incision, and it allows access for the patient-side surgeon to assist the console surgeon. Two additional ports are placed for the robotic arms. An antegrade cardioplegia needle is inserted into the ascending aorta through the working intercostal space. The ascending aorta is cross-clamped with a transthoracic aortic cross-clamp through a stab incision in the third intercostal space. The operative field is flooded with carbon dioxide. A standard longitudinal left atriotomy is performed. The left atrium is retracted using the Heartport retractor (Heartport, Inc, Redwood City, CA). The valve inspection, posterior leaflet resection, leaflet reapproximation, and ring annuloplasty (Cosgrove Edwards Annuloplasty Band, Edwards LifeScience, Irvine, CA) are all performed robotically. A quadrangular resection was performed when indicated, and the leaflets were reapproximated with a running suture. No annular plications or sliding annuloplasties were performed. All knot tying was also completed with the robot. Air was removed from the heart through the cardioplegia needle. A single chest tube was inserted to drain the right pleural space. The pericardium was not reapproximated, and pacing wires were not used. An intercostal nerve block with 1% Marcaine was performed before closing the chest. Anesthesia was planned to attempt intraoperative extubation in all patients.
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Table 3. Postoperative Data (n ⫽ 25) Variable CARDIOVASCULAR
Extubated in OR ICU (h) LOS (days) Discharged ⬍24 h Discharged ⬍30 h Pt’s requiring PRBC’s
N (%)
Mean ⫾ SD
Range
35.4 ⫾ 18.5 2.68 ⫾ 3.1
18 –72 1–16
21 (84%)
8 (32%) 12 (48%) 11 (44%)
ICU ⫽ intensive care unit; LOS ⫽ length of stay; OR ⫽ operating room; PRBCs ⫽ packed red blood cells; Pts ⫽ patients; SD ⫽ standard deviation.
Table 2 details the time it took to complete the procedure as well as several individual components of the operation. The total operating room time was just less than 300 minutes. The actual time it takes to robotically resect and repair the posterior leaflet averaged 20 minutes. Insertion of the annuloplasty ring, placing sutures, and tying them was less than 30 minutes. The remainder of the cross-clamp time is needed for exposing the valve, valve inspection, interval dosing of cardioplegia, removing air, and closing the left atrium. The majority of the patients (84%) were extubated in the operating room (Table 3). The 4 patients who required postoperative ventilation in the intensive care unit were extubated in less than 5 hours. All patients were up in a regular chair in the evening of the same day they underwent surgery. The chest tube was removed the following morning unless an air leak was present or the total drainage was greater than 500 mL. Indications for transfusion of packed red blood cells were a hematocrit less than 24% while rewarming on cardiopulmonary
Table 4. Postoperative Complications (n ⫽ 25) Conversion to sternotomy Reoperation for bleeding Neurologic TIAa CVA Wound infection Chest Groin Groin lymphocele Pulmonary Reintubation Prolonged air leakb Pleural effusion Renal failure A-fib a
Occurred 12 days after discharge. 24 h.
0 (0%) 0 (0%) 1 (4%) 0 (0%) 2 (8%) 0 (0%) 1 (4%) 0 (0%) 1 (4%) 1 (4%) 2 (8%) 5 (20%) b
Air leak requiring chest tube ⬎
A-fib ⫽ atrial fibrillation; CVA ⫽ cerebral vascular accident; ⫽ transient ischemic attack.
TIA
bypass or a hematocrit less than 24% in the postoperative period. Using these guidelines, 11 patients required perioperative transfusion of packed red blood cells. The average time in the intensive care unit was 35.4 hours, with an overall length of stay of only 2.68 days. Eight (32%) patients were discharged home from the intensive care unit in less than 24 hours after the completion of their operation. Table 4 outlines the nonvalve-related complications encountered with robotically assisted mitral valve repair. There were no deaths, no conversions to a standard sternotomy, and no reoperations for bleeding. Two patients had cellulitis of the intercostal incision, and there were no groin wound infections. One patient did experience a lymphocele of the groin requiring surgical drainage and closure. There were no strokes, but 1 patient did have a transient ischemic attack 12 days after discharge. A transesophageal echocardiogram was suggestive of thrombus on the sewing ring. The patient received anticoagulation treatment and experienced no further symptoms. Despite the aggressive extubation protocol, no patient required reintubation. One patient did have a prolonged air leak requiring continued chest tube drainage that extended the length of stay. One other patient had a late pleural effusion that required a thoracentesis at an outside hospital. Two patients had an elevated creatinine (renal failure) that required no treatment. Five patients exhibited atrial fibrillation postoperatively. Two of these occurred while in the hospital. Two patients required readmission for rate control, and 1 was managed as an outpatient. A total of 7 (28%) patients required readmission after discharge. Only 3 of these patients had been discharged in less than 24 hours initially. The average time from discharge to readmission was 7 days (range, 1 to 13 days). Echocardiograms performed at 30 days postoperatively (n ⫽ 24) revealed 12 (50%) patients had no mitral regurgitation, 11 (46%) patients had 1⫹ mitral regurgitation, and only 1 (4%) patient had 2⫹ mitral regurgitation. All patients were in New York Heart Association Class I and remain so at 12 to 24 months’ follow-up. Two patients ultimately required reoperation for mitral valve replacement. One patient was readmitted 3 days postoperatively for shortness of breath. An echocardiogram revealed new 2⫹ mitral regurgitation, which progressed to 3⫹ mitral regurgitation several days later. On reexploration the repair and ring were intact, but part of the anterior leaflet was torn from the annulus. The second patient was readmitted 40 days postoperatively for hemolytic anemia. Evaluation revealed 1⫹ to 2⫹ mitral regurgitation that was a high-velocity jet beneath an incompletely seated annuloplasty ring. At the time of valve replacement there was no evidence of infection. Table 5 divides our experience into two phases: the first 10 cases, which we considered our learning curve, and then our last 15 cases. There is a trend toward improved times for the overall procedure and cardiopulmonary bypass time, but they did not reach statistical significance. However, the cross-clamp time, leaflet resection or repair time, and annuloplasty ring time were
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Table 5. Initial Cases Versus Current Experience (n ⫽ 25)a
Comment
Variable
The evolution of minimally invasive mitral valve surgery continues to move forward. The early efforts, which involved modifications of the standard sternal incision, have now developed to the point at which the operation is performed almost entirely with robotic assistance. These stepwise improvements have followed the suggested steps and classification of minimally invasive cardiac surgery as reported by Loulmet and associates [5]. Successful series have been reported using port access, endovascular cardiopulmonary bypass, and aortic occlusion with a voice-controlled camera robotic arm [6, 7]. However, that technique requires the surgeon to learn new port access skills and the use of an endoaortic occlusion balloon, which can be difficult to position [8]. With the introduction of the transthoracic aortic crossclamp [9] and the da Vinci Surgical System, mitral valve repair can now be performed in a manner very similar to a standard sternotomy approach but with truly limited incisions. Nifong and colleagues [10] recently reported their successful initial results with the da Vinci system, which led to the multi-center trial. Because the technique and skills are familiar, there is a relatively short learning curve as demonstrated in the improvement in our series after the first 10 cases. Our operative times closely resemble those reported by Felger and coworkers [4] and Nifong and colleagues [10], who were able to show that mitral valve repair could be performed with similar operative times compared with standard techniques using a median sternotomy. Our current experience also demonstrates that robotically assisted mitral valve repair can be performed safely and with satisfactory early results. Realizing that mitral valve repair can be performed safely and with good long-term results through a sternotomy approach, is there any advantage to pursuing less-invasive mitral valve repair? Felger and coworkers [4] and Nifong and colleagues [10] now have a large experience with minimally invasive mitral valve repair and have shown clinical results equal to the conventional sternotomy approach but with decreased complications. In particular, there are fewer pulmonary complications and reoperations for bleeding. Intuitively, it would appear that this is a result of avoiding the sternotomy. We took this one step further with a planned anesthetic regimen to extubate the patients in the operating room. We successfully extubated more than 80% of patients in the operating room with no patient requiring reintubation. This has allowed for earlier ambulation and return of bowel function. Subsequently, patients can be considered for home discharge sooner with an average length of stay less than 48 hours in the last half of our experience. In those patients we discharged in less than 24 hours, 5 (63%) required no readmission and were seen only in the office as an outpatient. Because the readmission rate is not insignificant, the advantages of 24 to 48 hours postoperative discharge will require further evaluation. Chitwood and Nifong [11] have previously shown decreased costs of minimally invasive mitral valve repair compared
Total OR time (min) Procedure time (min) CPB time (min) Cross clamp time (min) Leaflet repair (min) Annuloplasty ring (min) LOS (days) a
1st 10 Cases
Last 15 Cases
p Value
318.5
275.1
0.003
209.9
192.2
0.345
137.2 97.6
119.5 81.1
0.093 0.050
26.2
15.6
0.001
31.9
24.8
0.007
4.2
1.67
0.043
Mean values.
CPB ⫽ cardiopulmonary bypass; operating room.
LOS ⫽ length of stay;
OR ⫽
significantly reduced in the second half of our experience. Our average length of stay is now down to 1.67 days, which is a significant improvement compared with our first 10 cases. Figure 1 demonstrates a typical wound 30 days postoperatively.
Fig 1. Typical right thoracic wounds on postoperative day 30.
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with conventional sternotomy. This was predominantly owing to a decrease in the length of stay. However, if one figures in the capital expenditure for the robot, service contracts, and disposable components, this becomes a controversial issue. There is no question that the better cosmetic result compared with a conventional sternotomy has improved our patient satisfaction. In our experience, 2 patients did require reoperation for recurrent mitral regurgitation. Both patients had less than 1⫹ mitral regurgitation on their initial postoperative echocardiogram. The first patient had a partially torn anterior leaflet at the time of reoperation. This appeared to be a technical problem that was unrecognized at the initial procedure. The second patient had hemolysis from an incompletely seated annuloplasty ring. Because there is no tactile sensation, the knot tying depends on visual clues as to appropriate tension and tightness. Currently, the ring is inspected, including manipulation to make sure that it is snug on the annulus. Both of these failures occurred earlier in our overall experience. Thus, the learning curve includes not only a gradual improvement in times but an improvement in decision making and evaluating the valve repair itself. If the goal of minimally invasive mitral valve surgery is to perform the operation with reduced surgical trauma, decreased pain, fewer complications, improved cosmesis, shorter length of stay, and earlier return to a normal daily activity for the patient, then we believe that our series, as well as those by Casselman and associates [3], Felger and colleagues [4], Reichenspurner and associates [6], and Mohr and coworkers [7], has demonstrated the potential advantages of minimally invasive mitral valve surgery. However, the ultimate test will be the long-term durability and need for reoperation compared with a conventional sternotomy approach. Mohty and colleagues [12] have clearly established these long-term outcomes, which minimally invasive mitral valve surgery will have to match. Our study has provided additional information to the potential advantages of minimally invasive mitral valve surgery, such as improved cosmesis and fewer bleeding and pulmonary complications. The majority of patients can be extubated in the operating room with early ambulation. The role of early discharge (⬍48 hours) needs additional evaluation owing to the relatively high
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readmission rate. Our patient population was generally young and healthy with good ventricular function. Whether or not this technique is feasible for morecomplex repairs or in elderly, sicker patients remains to be determined. Also, longer follow-up is needed to determine whether robotically assisted mitral valve repair in this select patient population is durable and will compare favorably to the 5- and 10-year results achieved through a sternotomy approach.
References 1. Cohn LH, Adams DH, Couper GS, et al. Minimally invasive cardiac valve surgery improves patient satisfaction while reducing costs of cardiac valve replacement and repair. Ann Thorac Surg 1997;226:421–8. 2. Cosgrove DM, Sabik JF, Navis JL. Minimally invasive valve operations. Ann Thorac Surg 1998;65:1535–9. 3. Casselman FP, Slycke SV, Dom H, Lambrechts DL, Vermeulen Y, Vanermen H. Endoscopic mitral valve repair: feasible, reproducible and durable. J Thorac Cardiovasc Surg 2003;125:273–82. 4. Felger JE, Chitwood WR, Nifong LW, Holbert D. Evolution of mitral valve surgery: toward a totally endoscopic approach. Ann Thorac Surg 2001;72:1203–9. 5. Loulmet DF, Carpentier A, Cho PW, et al. Less invasive methods for mitral valve surgery. J Thorac Cardiovasc Surg 1998;115:772–9. 6. Reichenspurner H, Boehm DH, Gulbins H, et al. Threedimensional video and robot-assisted port-access mitral valve operation. Ann Thorac Surg 2000;69:1176 –82. 7. Mohr FW, Onnasch JF, Falk V, et al. The evolution of minimally invasive mitral valve surgery—2 year experience. Eur J Cardiothorac Surg 1999;15:233–9. 8. Schneider F, Falk V, Walther T, Mohr FW. Control of endoaortic clamp position during port-access mitral valve operations using transcranial Doppler echography. Ann Thorac Surg 1998;65:1481–2. 9. Chitwood WR, Elbeery JR, Moran JF. Minimally invasive mitral valve repair using transthoracic aortic occlusion. Ann Thorac Surg 1997;63:1477–9. 10. Nifong LW, Chu VF, Bailey BM, et al. Robotic mitral valve repair: experience with the da Vinci system. Ann Thorac Surg 2003;75:438 –43. 11. Chitwood WR, Nifong LW. Minimally invasive videoscopic mitral valve surgery: the current role of surgical robotics. J Card Surg 2000;15:61–75. 12. Mohty D, Orszulak TA, Schaff VH, Avierinos JF, Tajik JA, Sarano ME. Very long-term survival and durability of mitral valve repair for mitral valve prolapse. Circulation 2001; 104(Suppl 1):I-1–7.
DISCUSSION DR W. RANDOLPH CHITWOOD (Greenville, NC): First, I would like to thank the authors for participating in the da Vinci Multicenter Mitral Valve Study in which 10 centers participated, as well as supplying me with the advanced copy of their manuscript. Doctor Tatooles and his coauthors have provided us, in an excellent presentation, data that support the continued exploration of using robotic assistance, or what really is telemanipulation, to do complete mitral valve repairs through truly minimal access incisions. These types of well-regulated clinical trials remain the touchstones for The Society for Thoracic Surgeons and our surgical specialties to advance and improve therapy for
our patients. This is what it is all about. The results that Dr Tatooles and others have shown us today, and during the last several years, are helping to create a safe ascent up the Everest slope to a truly endoscopic mitral valve operation. Despite encouraging advancements, there are really three cautions for surgeons who choose this pathway of technologic development and applicative therapy. With these new devices and technologies, there are completely new learning curves, and albeit shortened by the amazing telemanipulative abilities of these devices, everyone must enter a common portal to a format that sets surgeons, both young and old, nearly at the same starting level.
Second, we must not fool ourselves into thinking that this is a lesser operation because there is less tissue injury. The operation must be done with the same quality, long-term results, and standards for mitral valve repair surgery to which Professor Carpentier and others have held us. Last, any surgeon who does traditional mitral valve surgery well can provide his or her patients new benefits with these devices, but only if they have patience and can develop a completely new way of thinking about a way to do cardiac surgery. Doctor Tatooles has performed 25 mitral valve repairs along a well-planned protocol in which posterior leaflet resections were done, followed by a repair, and insertion of an annuloplasty band. All patients were followed by a protocol, through a third-party echocardiographic core laboratory, with follow-up transthoracic studies done 1 month after surgery. There were no deaths or incisional conversions in his group, and no strokes or myocardial infarctions occurred. One patient had a transient ischemic attack 7 days after discharge. Of all patients, 84% were extubated in the operating room, and the average length of stay was 2.7 days, which is the lowest in the multicenter trial that averaged 4.7 days in 112 patients. This is compared with the year 2002 STS data that showed a total length of stay of 8.5 days for repairs in nearly 900 patients. In Dr Tatooles’s series, there were seven readmissions, or 28%, and two reoperations requiring a valve replacement. Forty-four percent of his patients received a transfusion. What Dr Tatooles has added to the multicenter protocol is a custom “fast track” anesthesia protocol with the intent of early extubation and early hospital discharge. In addition to a good repair, the course goal for the patient seems to have been preset, mainly at the very beginning, on rapid patient mobilization and cost reduction. Who can argue with these premises? However, although his cross-clamp, perfusion, and ventilatory times were significantly less than in our 60 patients, or many other patients in the multicenter trial, you still transfused 44% of your patients versus our 15% who received blood products. Moreover, your readmission rate was 28%. I was pleased to see that the cardiologists are referring to you patients who have severe regurgitation but are either asymptomatic or in no more than moderate congestive heart failure. Many are finding that these patients benefit most from a good repair by preventing atrial fibrillation and eventual ventricular impairment. I have several questions that arise from your study as well as from our observations and experience. You had two valve replacements, one within the first week from leakage and one at 40 days from hemolysis. Interestingly, we had a patient in our series who developed severe hemolysis and at reoperation was found to have a portion of the band that was not sewn flush with the tissue, creating a small fabric loop, which caused severe hemolysis. This patient had to have the valve replaced. This was in our early patient group, when our average number of sutures was eight. In your series, 76% of patients had only six sutures placed in a 28-mm Cosgrove annuloplasty band. In our last 30 of 60 patients, we have averaged 11 sutures to avoid this problem. Doctor Tatooles, are you expecting more hemolytic problems in your early patients and have you modified your technique since this reoperation? The ring or band must be placed as tight to the annular tissue as with sternotomy access. Clearly, the main reason that you were able to discharge your patients so early relates to your anesthetic method, early extubation, efficient pain control, liberal transfusions, and guided mobilization.
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We can learn a lot from this plan in managing all minimally invasive surgical patients. However, your 28% readmission rate bespeaks the fact that there seems to be an obligatory hospitalization period for any patient who undergoes any invasive cardiac procedure requiring perfusion and cardioplegic arrest. Our readmission rate has been almost nil, and we have not transfused nearly as many patients as have you, nor used a fast-track anesthesia protocol. In fact, our cardiopulmonary perfusion times are longer than yours, yet our length of stay is only a day or two longer at a mean of 3.9 days. Please comment on your readmissions and the reason for them. Last, having been a leader in this area, do you believe that we can achieve truly endoscopic telemanipulation for mitral surgery with instrument arms only without the need for even a small incision, and what are your thoughts for the future? Are there adjunctive facilitating technologies that are being developed that will help us? You and your colleagues are to be congratulated on a scientifically planned and well-executed study, for your honest results, for your excellent presentation, and for your solid attempts to improve patient care through the development of care protocols and new technologic methods, namely, computer-assisted telemanipulation using robotic devices. I would like to thank Drs Baumgartner, Guyton, and Murray as well as the scientific program committee for a superb meeting, and to thank the Society for the privilege of discussing this paper. God bless America. DR TATOOLES: Doctor Chitwood, thank you for your kind comments and your pioneering work in minimally invasive surgery and application of robotic techniques. In regards to our valve replacement, one patient did have a partial dehiscence of the posterior aspect of the annuloplasty ring. The etiology of this problem was not defined, but it may have been related to the number of sutures placed or to the technique of suture placement. Annuloplasty sutures are tied after the placement of each suture. This differs from our open technique and may increase the risk of ring dehiscence if the suture pulls partially through the annulus during placement of the subsequent stitch or kinks the annuloplasty ring. Placement of additional sutures may decrease the risk of ring dehiscence so long as sutures are placed under adequate tension to seat the ring against the annulus. We do not anticipate, nor have we seen, other patients developing complications related to hemolysis or ring dehiscence but will continue to follow our patients closely. In regards to our readmission rate, three of twelve patients discharged home on their first postoperative day were readmitted. Of these, one returned for symptomatic atrial fibrillation, one for upper extremity phlebitis, and one for a pleural effusion. An extended hospital stay would not have likely altered these complications. Early discharge did not contribute to postoperative morbidity, and select patients with close follow-up can be safely discharged on their first postoperative day. Although we did not specifically look at risk factors for transfusion requirements, 44% of our patients did receive blood or blood products. Early treatment of anemia may have facilitated our expedited discharge protocol; further evaluation of our transfusion threshold may decrease our perioperative use of blood and blood products. I would like to thank the Society for the privilege of allowing us to present our work. Thank you.
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Appendix A Inclusion Criteria CARDIOVASCULAR
1. 18 to 80 years of age 2. Has clinically significant mitral valve regurgitation (grade 3 or 4) 3. Has signed informed consent
Preoperative Exclusion Criteria 1. Has any of the following echocardiographic findings: a. Mitral valve stenosis with moderate to severe mitral valvular calcification (any grade) b. Severely calcified mitral valve annulus c. Moderate to severe tricuspid valve insufficiency (grade 3 or 4) d. Moderate to severe aortic valve regurgitation or stenosis (grade 3 or 4) e. Left ventricular ejection fraction less than 0.30 2. Has a history of acute myocardial infarction in preceding 30 days before proposed mitral valve surgery 3. Has hemodynamic instability with or without mitral valve disease or myocardial infarction 4. Has severe coronary artery disease requiring multivessel coronary artery bypass grafting 5. Has concomitant acute bacterial endocarditis 6. Has a previous right thoracotomy 7. Has a body mass index more than 35 kg/m2 8. Has an anatomy unsuitable for endoscopic visualization of the thorax, eg, morbid obesity with remarkable axillary adiposity or physical deformities of the thorax 9. Has symptoms of severe asthma, emphysema, chronic obstructive pulmonary disease, or pulmonary fibrosis, or other evidence of pulmonary decompensation
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10. Has significant hepatic compromise (cirrhosis, hepatitis, liver failure) 11. Has dialysis-dependent renal failure 12. Has untreated cerebrovascular disease 13. Has severe bleeding disorder 14. Has undergone previous radiation therapy of the mediastinum or right thorax 15. Has connective tissue disease (e.g., Marfan’s syndrome, Ehlers-Danlos syndrome) 16. Has uncontrolled diabetes mellitus 17. Is unable to give informed consent 18. Is pregnant
Appendix B Premedication Midazolam 1 to 3 mg intravenously
Induction Sufentanil 1 to 2 g/kg intravenously Etomidate 0.2 to 0.5 mg/kg intravenously
Maintenance Propofol 50 to 75 g · kg⫺1 · min⫺1 intravenously Sevoflurane 0% to 2% inhalation
Reversal Neostigmine 5 mg intravenously Robinul 1 mg intravenously
Postoperative Analgesia Ketorolac tromethamine 15 to 30 mg every 6 hours intravenously Morphine sulfate 1 to 5 mg every hour as needed intravenously