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Department of Cardiac Surgery, Heartcenter, Leipzig University, Struempelstrasse 39, 04289 Leipzig, Germany
Received 3 September 2007; received in revised form 30 April 2008; accepted 7 May 2008.
* Corresponding author. Tel.: +49 341 8651421; fax: +49 341 8651452. (Email: j.seeburger{at}web.de).
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Abstract |
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 Top Abstract 1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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Key Words: Mitral valve repair • Minimal invasive technique
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1. Introduction |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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We have a large experience with minimal invasive MV surgery, dating back to the late 1990s [1,2]. The aim of this study therefore was to review our early and mid-term results and to examine the feasibility, safety and effectiveness of minimal invasive MV repair in patients with mitral regurgitation (MR).
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2. Material and methods |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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2.1 Surgical technique
Cardiopulmonary bypass (CPB) was instituted via femoral arterial and venous cannulation through a 3–4 cm transverse incision in the right groin. The tip of the venous cannula was positioned under transesophageal echocardiographic (TEE) guidance in the right atrium. In those patients requiring concomitant tricuspid valve repair, a second venous cannula was inserted percutaneously through the right internal jugular vein and positioned in the superior vena cava. Patient temperature was cooled to 34 °C and vacuum-assisted CPB was used throughout the procedure.
A right lateral mini-thoracotomy, 5–6 cm in length, was performed in the 4th intercostal space. The incision was placed just below and lateral to the nipple in men, and in the submammary crease in women. The length of the incision was measured intraoperatively and recorded prospectively. Patients were placed on CPB prior to opening the pleura. A small thoracic and soft tissue retractor was utilized. A video camera was inserted through a 10 mm port in the right 2nd intercostal space and a transthoracic Chitwood aortic cross-clamp was inserted through a 5 mm incision in the 3rd intercostal space [6]. Antegrade crystalloid Bretschneider cardioplegia (2 l) was administered directly into the aortic root, and then repeated in 90–120 min if necessary. The surgical field was flooded with carbon dioxide through the camera port throughout the procedure.
The left atrium was opened posterior to the interatrial groove. A left atrial retractor was used to expose the MV. Specialized surgical tools were utilized for tissue handling and suturing (Geister Inc., Tuttlingen, Germany). Standard MV repair techniques were employed (discussed below). Deairing was performed by filling the left atrium with saline during closure and via the cardioplegia puncture site on the ascending aorta.
2.2 Patients
The mean preoperative MR grade was 3.3 ± 0.6, preoperative left-ventricular ejection fraction was 59.2 ± 15.1%, mean age was 60.3 ± 12.7 years, and 819 patients (61.2%) were male. Previous cardiac operations had been performed in 81 patients (6.1%). Preoperative patient characteristics are depicted in Table 1
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2.4 Statistical analysis
Categorical variables are expressed as proportions and continuous variables as mean ± standard deviations throughout the manuscript. Survival and freedom from reoperation were analyzed with Kaplan–Meier actuarial methods. All analyses were performed using the SAS JMP7.0 program (SAS Institute, Cary, NC, USA). Guidelines for reporting morbidity and mortality after cardiac valvular operations were observed [7].
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3. Results |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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MV repair techniques included ring annuloplasty in 1301 patients (96%), with 78% receiving complete mitral rings and 22% partial rings. The mean implanted ring size was 31.1 ± 3.6 mm. Implantation of Gore-Tex neo-chordae (the so-called ‘loop technique’) [8] was performed on the anterior mitral leaflet (AML) in 260 patients (19.4%) and on the posterior mitral leaflet (PML) in 415 patients (31%). Carpentier-type leaflet resection of prolapsing segments was performed on the AML in 29 patients (2.2%) and on the PML in 348 patients (26%). There was an increasing trend towards implantation of Gore-Tex neo-chordae since 2003, with a concomitant decreasing application of Carpentier-type leaflet resection techniques. Alfieri repair was used as a bailout procedure in 44 patients (3.3%). Complete details on the MV repair procedures are depicted in Table 3 . The mean total operating time was 165 ± 47 min, mean duration of CPB was 121 ± 38 min, and mean aortic cross-clamp time was 70 ± 32 min. The mean incision length of the lateral mini-thoracotomy was 5.3 ± 1.1 cm.
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Predischarge echocardiography showed a mean MR grade of 0.2 ± 0.5 (median 0, range 0–3+), with mild or less MR present in 96.9% (n = 1297) of patients.
The Kaplan–Meier estimate for survival at 5 years was 82.6% (95% CI: 78.9–85.7%) (Fig. 1 ). Freedom from mitral valve-related reoperation 5 years postoperatively was 96.3% (95% CI: 94.6–97.4%; Fig. 2 ).
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4. Discussion |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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MV repair is known to be the gold standard for patients with MR and several large series have documented excellent results for MV repair through a standard sternotomy [10–12]. Some critics of minimal invasive surgery have claimed that minimal invasive MV repair may be less frequently performed (i.e. more MV replacements) or that the repair may be less durable than those performed through a standard sternotomy. Minimal invasive MV repair may be more difficult and technically challenging because of limited operative space, the need for video assistance, and decreased surgical maneuverability when compared to conventional surgery through a full sternotomy. However, we were able to perform a MV repair procedure in 87.2% of MR patients operated on with a minimal invasive technique over the 8-year time period of the current study. In addition, early echocardiography revealed mild or less MR in 96.7% of patients. We therefore feel confident in stating that minimal invasive MV repair is imminently achievable in patients with MR.
Our only exclusion criteria for a minimal invasive approach in patients with MR are those who have undergone a previous right thoracotomy, because the resulting adhesions make dissection of the mediastinum without injury to the lung a significant challenge. In addition, patients requiring urgent surgery when the on-call surgeon did not have adequate training in the minimal invasive technique received a standard operation through a sternotomy. Of all patients with MR who underwent surgery at our institution during the study period, 86.1% (1760 of 2044) received a minimal invasive operation. Although we are able to perform certain concomitant procedures through a right-sided mini-thoracotomy (i.e. tricuspid valve surgery, closure of a patent foramen ovale or atrial septal defect, or atrial fibrillation ablation), patients who require concomitant coronary bypass, aortic valve or ascending aorta surgery are not candidates for a minimal invasive approach.
Several different MV repair techniques exist, and many of them were successfully applied through a minimal invasive approach in the current series. The three most commonly used techniques in the current series were ring annuloplasty, Carpentier-type leaflet resection with our without a sliding plasty, and implantation of Gore-Tex neo-chordae without any leaflet resection (the so-called ‘loop technique’, see below). As we gathered more experience with the loop technique and as we observed highly satisfactory intraoperative and early echocardiographic results, implantation of Gore-Tex neo-chordae has become our procedure of choice over time with a simultaneous decrease in the number of leaflet resections performed.
The loop technique involves the implantation of premeasured Gore-Tex sutures as neo-chordae and was first described by our group in 2000 [8]. Four equilength loops are formed from a single Gore-Tex suture, with each loop secured onto a single felt pledget. The distance between the papillary muscle and the plane of the annulus is assessed using a custom made measuring device. A correspondingly sized premeasured Gore-Tex loop suture is then fixed to the body of the papillary muscle. The four free loops from this suture are then secured, with additional Gore-Tex sutures, to the prolapsing portion of the leaflet at the line of coaptation. As our confidence with the loop technique continues to increase, we are now applying it not only in minimal invasive MV surgery but also during conventional full sternotomy MV repair [13,14]. Although the long-term results for this technique are currently unknown, our medium-term results are positive [14].
As reported by other investigators [3], we encountered one case of aortic dissection during minimal invasive MV surgery. However, as aortic dissection is a very serious complication, we prefer to use the transthoracic aortic cross-clamp introduced by Chitwood et al. [6]. If preoperative tests reveal an extremely calcified ascending aorta or severe adhesions in cases of reoperation, then ventricular fibrillation or beating-heart surgery with CPB support are alternatives to aortic clamping. In addition to the one patient with aortic dissection, conversion to a full sternotomy was required in one other patient because of atrio-ventricular separation and in two patients for excessive intraoperative bleeding. In one case of bleeding we identified the cause to be an injury of the apex of the ventricle from the catheter used to inject saline for assessment of valvular competence. In the other case the bleeding was coming from the atrial appendage for an indiscernible reason. Despite these complications, our intraoperative conversion rate to full sternotomy was very low (0.3%) and therefore reflects the feasibility and safety of the minimal invasive approach for MV repair.
The 5-year survival and freedom from mitral valve-related reoperations were favorable in the current study at 82.6% and 96.3%, respectively. Over 200 patients were available for analysis at 5-year follow-up (Figs. 1 and 2) and therefore we are very confident in these estimates. We feel that our results for minimal invasive MV repair are promising and durable. However, we were unable to obtain a contemporary control group for the current study since minimal invasive MV surgery has been our procedure of choice since the late 1990s. We therefore sought to compare our results with the results of conventional, full sternotomy MV surgery as reported in the literature. Freedom from reoperation and survival are two key issues that need to be taken into account when making such comparisons between studies.
David et al. reported a series of 701 patients who underwent MV repair for MR due to myxomatous disease using the conventional approach between 1981 and 2001 [10]. The freedom from reoperation at 12 years was 96% for isolated posterior leaflet prolapse, 88% for anterior leaflet prolapse, and 94% for bileaflet prolapse. The overall survival at 12 years was 75%, with no difference regarding the extent of leaflet prolapse. Echocardiographic follow-up revealed freedom from moderate or severe MR at 12 years of 80% for PML, 65% for AML, and 67% for bileaflet prolapse.
A similar study published by Gillinov et al. identified factors influencing the durability of conventional MV repair via sternotomy [11]. His group reviewed a series of 1072 patients operated on between 1985 and 1997 for myxomatous MR. The freedom from reoperation at 10 years was 93% for all patients, with the greatest durability observed in patients with isolated posterior leaflet prolapse treated with resection and annuloplasty.
Another large series by Suri et al. assessed 1411 patients with isolated MR due to leaflet prolapse who underwent conventional MV surgery between 1980 and 1999 [12]. A total of 83% of patients underwent MV repair. The freedom from reoperation was 93% 5 years postoperatively. The investigators concluded that MV repair provides excellent survival and emphasized the use of ring annuloplasty.
De Bonis et al. compared two leaflet repair techniques for MV repair, the edge-to-edge technique and the quadrangular resection technique [15]. Between 1991 and 2004, a total of 133 patients with anterior leaflet prolapse, and 605 with posterior leaflet prolapse, underwent conventional MV surgery for myxomatous disease. At 10 years overall survival was 92% and freedom from reoperation was 96%, with no differences between patients with AML and PML prolapse.
Rey Meyer at al. published a risk factor analysis of 175 adults who underwent MV repair associated with other cardiac procedures between 1986 and 1998 [16]. Kaplan–Meier analysis revealed a 96% survival at 1 year, 88% survival at 5 years, and 69% survival at 10 years. NYHA III–IV symptoms, poor ejection fraction, functional MR, and ischemic MR were identified as independent predictors of late death. Risk factors for reoperation were persistent MR at hospital discharge, age below 60, and absence of an annuloplasty ring.
We observed low rates of perioperative morbidity and mortality in the current study, which confirms the safety of a minimal invasive MV repair. Although our long-term survival was lower than in some of the other series quoted above, it is important to note that approximately one-quarter of our patients were 70 years of age or older and that over 10% had a severely reduced left-ventricular ejection fraction. Given the complex valvular pathologies of patients who underwent successful MV repair and the high repair rate (87.2%) of all MR patients who were operated on via a minimal invasive approach, we feel confident in saying that the procedure is definitely feasible in MR patients. Furthermore, our long-term freedom from reoperation (96.3% at 5 years) compares favorably to the abovementioned studies of conventional, full-sternotomy MV repair [10–12]. We can therefore conclude that minimal invasive MV repair is also durable, at least in the medium term. When we consider that minimal invasive MV surgery has been demonstrated to offer benefits such as improved cosmesis, less surgical tissue damage, less postoperative pain, decreased risk of wound infection, better patient satisfaction, and improved quality of life [17–20], we can imply that such operations offer an attractive alternative to conventional MV surgery.
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5. Conclusion |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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Appendix A |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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Dr H. Vanermen (Aalst, Belgium): I can only applaud every surgical team who is trying to lessen the invasiveness of cardiac surgery, and then if this can be done keeping in mind the gold standard the way you did, then I congratulate you, really. It is amazing that you had the repair rate, you had over 85%, you have a remarkably low mortality in this series, and it coincides perfectly with our series of 1500 patients. I have a couple of questions.
Redo situations are particularly challenging, especially when patients have two or three sternotomies, and I wonder how you cope with these redo situations with a transthoracic clamp. That is my first question. I assessed that you combined 6.3% of the mitral valve repairs to the tricuspid, and I think that is actually rather low with the modern standards of tricuspid valve dilatation that we found in many of these patients. And the third question is, I know that you have some experience with robotic mitral valve surgery. To which point are you continuing that effort, and is there any continuing effort actually to come to the ultimate step, that is to say, the non-rib-spreading totally endoscopic technique?
Dr Seeburger: I understood the first two questions but would you please repeat your third question?
Dr Vanermen: The third one is the ultimate step of minimally invasive surgery for me is the totally endoscopic with a non-rib-spreading technique. How about that?
Dr Seeburger: In your first question you addressed the redo operations in this cohort of patients. We have analyzed these data, but unfortunately I do not have them at hand right now. But generally speaking, most of these patients had previously undergone CABG surgery and in order to avoid patent graft injury the minimally invasive approach is valuable.
Your second question regarding the fairly low percentage of concomitant tricuspid valve surgery, you may have to keep in mind that all of these patients presented with predominant mitral valve regurgitation and the proportion of comorbidities was rather low. This may be vague and we will be looking at this further.
In your third question you asked for as you name it the ultimate step of minimally invasive surgery with no rib-spreading. I would like to hand this question over to Professor Mohr, who can certainly give you more details on that.
Dr Mohr: I would like to stand up a little bit. He is in his early stages of his career and he may not be able to answer all the technical details.
To address the question of reoperations, we usually do reoperations on beating or fibrillating hearts and just depending how the pathology of the mitral valve disease is. If it is functional MR, we usually cool the patient down, we don’t cross-clamp at all, because most of the proximal anastomoses are patent and the IMA grafts are patent. So we don’t want to get into any problems. And also if mitral valve replacement is necessary, it can be done easily. If we end up with a very, very complex repair like a Barlow in such a situation, it is something which is more complex and we have to consider other ways to really arrest the heart. But in this series I think most of the patients were done in hypothermia, by 26 degrees, low perfusion. Sometimes if there is a difficult stitch, we stop extracorporeal circulation and perform the repair.
And to address the issue of completely video-assisted surgery like you perform, in our group we have four or five surgeons who perform the procedure, and we both always have the question whether we spread the ribs or don’t spread the ribs. I think I am the only one who is doing very often complete video-controlled surgery, and all the others, they make it more simple for them. They just look through the keyhole more often because they have a better 3D control, and I am happy that we have five surgeons who can perform the procedure that way. I don’t think that there will be so many experts who really can jump to the next step.
And also addressing robotic surgery, we stopped robotic surgery in 2002 because of the increasing numbers of patients we see. We see sometimes four patients in parallel every day, and this is too much for our one robotic device. And I personally don’t see a big advantage using robotics, especially if you get more complex cases, and Dr Kuntze will focus on the bileaflet repairs we do. At least if you want to do multiple cases, it would be for us impossible to continue there. That is why we decided not to follow this pathway.
Dr E. De Worm (Antwerp, Belgium): I have a question concerning the one aortic dissection you had. Were you able to find out whether they were clamp-related or femoral cannulation-related?
Dr Seeburger: I have no information on that, but maybe Dr Kuntze can give you some more details.
Dr Mestres (Barcelona, Spain): Yes, but it seems that it was cannulation-related as I have heard, isn’t it?
Dr Kuntze: Yes, it was cannulation-related.
Dr R. Dion (Genk, Belgium): I just want to congratulate your group because it now approaches or even equalizes the results of the best surgeons who are operating through a sternotomy.
A few comments and a few questions. First, we retrospectively have looked in Leiden for the sternal problems in isolated mitral valve conventional surgery over the last 8 years and have to stress that they virtually do not exist. Therefore the sternotomy approach remains a very acceptable one indeed.
The second point – and Friedrich Mohr alluded to it, and this is also the opinion of one of my talented young colleagues in Leiden having experience in port-access mitral surgery – is that one seems to lack the perfect three-dimensional approach for the valve analysis and repair in complex cases, for instance, repositioning of a papillary muscle.
My third comment is about the future. Don’t you think that, in the future, the minimally invasive approach will be based on indirect imaging, like on-line MRI or CT or 3D echo and not anymore on direct vision or on video? And, in this prospect, what will remain of the techniques that your group is using now, which in fact have more to do with minimal access than with minimal invasiveness?
And my last question: you are working in a center which is well equipped and you are surrounded by experienced surgeons who are beyond their learning curve in conventional mitral valve repair and in port-access surgery. Even in these exceptional conditions, how long do you think it will take you to master these techniques and get such good results?
Dr Seeburger: May I give you my personal view. As a matter of fact I have just started my career, but generally I think that everything is moving forward, and so does cardiac surgery. I have seen some of these new techniques evolving, and I see them at the center where I work. And I am convinced that the future steps will be towards minimally invasive surgery and even towards total endoscopic or percutaneous procedures. I believe that this is one of the ways that we have to pursue.
And frankly spoken, to become one of these surgeons who are able to successfully handle these techniques, I am sure it takes a few years, but I don’t know how long exactly. I cannot tell you that because I haven’t gone through this training program yet.
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Footnotes |
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Presented at the 21st Annual Meeting of the European Association for Cardio-thoracic Surgery, Geneva, Switzerland, September 16–19, 2007. |
References |
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TopAbstract1. Introduction2. Material and methods3. Results4. Discussion5. ConclusionAppendix AReferences |
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This article has been cited by other articles:
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  R. M. Suri, H. V. Schaff, S. R. Meyer, and W. C. Hargrove III Thoracoscopic versus open mitral valve repair: a propensity score analysis of early outcomes. Ann. Thorac. Surg., October 1, 2009; 88(4): 1185 - 1190. [Abstract] [Full Text] [PDF]
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 J. Seeburger, M. A. Borger, N. Doll, T. Walther, J. Passage, V. Falk, and F. W. Mohr Comparison of outcomes of minimally invasive mitral valve surgery for posterior, anterior and bileaflet prolapse Eur. J. Cardiothorac. Surg., September 1, 2009; 36(3): 532 - 538. [Abstract] [Full Text] [PDF]
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J. Seeburger, V. Falk, M. A. Borger, J. Passage, T. Walther, N. Doll, and F. W. Mohr Chordae Replacement Versus Resection for Repair of Isolated Posterior Mitral Leaflet Prolapse: A Egalite Ann. Thorac. Surg., June 1, 2009; 87(6): 1715 - 1720. [Abstract] [Full Text] [PDF]
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J. Seeburger, M. A. Borger, V. Falk, J. Passage, T. Walther, N. Doll, and F. W. Mohr Minimally invasive mitral valve surgery after previous sternotomy: experience in 181 patients. Ann. Thorac. Surg., March 1, 2009; 87(3): 709 - 714. [Abstract] [Full Text] [PDF]
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