Endoscopic placement of multiple artificial chordae with robotic assistance and nitinol clip fixation

A simple technique of artificial chordae implantation in robotic cardiac surgery using a novel tube device supporting expanded polytetrafluoroethylene chordae ligation

Artificial chordae implantation is an important technique for treating leaflet lesions in mitral valve repair. Considering that the expanded polytetrafluoroethylene (ePTFE) suture is slippery on the surface, adequate ligation without laxity should be critically considered, especially in robotic surgery. To resolve this issue, we applied a novel device that controls the length of an ePTFE suture (Chordarizer) for artificial chordae implantation in robotic mitral valve repair. After assessing the mitral valve via the right side of the left atrium, we stitched a CV-4 ePTFE suture to the target papillary muscle. Using a calliper, we measured the length of the artificial chordae and passed the CV-4 through the appropriate Chordarizer. Then, we stitched the CV-4 to the tip of the leaflet from the left ventricle side and tied it using da Vinci arms. Finally, the Chordarizer was peeled away. Chordarizer ensured safe and reliable artificial chordae implantation procedures with robotic mitral surgery, by maintaining the desired CV4 length.

Conditional long-term survival following minimally invasive robotic mitral valve repair: a health services perspective

BACKGROUND

Conditional survival is defined as the probability of surviving an additional number of years beyond that already survived. The aim of this study was to compute conditional survival in patients who received a robotically assisted, minimally invasive mitral valve repair procedure (RMVP).

METHODS

Patients who received RMVP with annuloplasty band from May 2000 through April 2011 were included. A 5- and 10-year conditional survival model was computed using a multivariable product-limit method.

RESULTS

Non-smoking men (≤65 years) who presented in sinus rhythm had a 96% probability of surviving at least 10 years if they survived their first year following surgery. In contrast, recent female smokers (>65 years) with preoperative atrial fibrillation only had an 11% probability of surviving beyond 10 years if alive after one year post-surgery.

CONCLUSIONS

In the context of an increasingly managed healthcare environment, conditional survival provides useful information for patients needing to make important treatment decisions, physicians seeking to select patients most likely to benefit long-term following RMVP, and hospital administrators needing to comparatively assess the life-course economic value of high-tech surgical procedures.

Videoscope-assisted cardiac surgery

Videoscope-assisted cardiac surgery (VACS) offers a minimally invasive platform for most cardiac operations such as coronary and valve procedures. It includes robotic and thoracoscopic approaches and each has strengths and weaknesses. The success depends on appropriate hardware setup, staff training, and troubleshooting efficiency. In our institution, we often use VACS for robotic left-internal-mammary-artery takedown, mitral valve repair, and various intra-cardiac operations such as tricuspid valve repair, combined Maze procedure, atrial septal defect repair, ventricular septal defect repair, etc. Hands-on reminders and updated references are provided for reader's further understanding of the topic.

Systematic review of robotic minimally invasive mitral valve surgery

BACKGROUND

Robotic telemanipulators have evolved to assist the challenges of minimally invasive mitral valve surgery (MVS). A systematic review was performed to provide a synopsis of the literature, focusing on clinical outcomes and cost-effectiveness.

METHOD

Structured searches of MEDLINE, Embase, and Cochrane databases were performed in August 2013. All original studies except case-reports were included in qualitative review. Studies with ≥50 patients were presented quantitatively.

RESULTS

After applying inclusion and exclusion criteria to the search results, 27 studies were included in qualitative review, 16 of which had ≥50 patients. All studies were observational in nature, and thus the quality of evidence was rated low to medium. Patients generally had good left ventricular performance, were relatively asymptomatic, and mean patient age ranged from 52.6-58.4 years. Rates of intraoperative outcomes ranged from: 0.0-9.1% for conversion to non-robotic surgery, 106±22 to 188.5±53.8 min for cardiopulmonary bypass (CPB) time and 79±16 to 140±40 min for cross-clamp (XC) time. Rates of short-term postoperative outcomes ranged from: 0.0-3.0% for mortality, 0.0-3.2% for myocardial infarction (MI), 0.0-3.0% for permanent stroke, 1.6-15% for pleural effusion, 0.0-5.0% for reoperations for bleeding, 0.0-0.3% for infection, and 1.1-6% for prolonged ventilation (>48 hours), 1.5-5.4% for early repair failure, 12.3±6.7 to 36.6±24.7 hours for intensive care length of stay, 3.1±0.3 to 6.3±3.9 days for hospital length of stay (HLOS) and 81.7-97.6% had no or trivial mitral regurgitation (MR) before discharge.

CONCLUSIONS

All subtypes of mitral valve prolapse are repairable with robotic techniques. CPB and XC times are long, and novel techniques such as the Cor-Knot, Nitinol clips or running sutures may reduce the time required. The overall rates of early postoperative mortality and morbidity are low. Improvements in postoperative quality of life (QoL) and expeditious return to work offset the increase in equipment and intraoperative cost. Evidence for long-term outcomes is as yet limited.

Dynamic evaluation of the loop technique using the U-Clip

Background

We set out to evaluate mitral valve repair with the loop technique under dynamic conditions, using a U-Clip to anchor the loop unit to a papillary muscle.

Methods

Mitral valve prolapse was artificially developed by resecting 4 chordae tendineae of a resected porcine heart. The loop unit was anchored to the papillary muscle using U-Clips. Each chordal loop was fixed on the prolapsed leaflet. A roller pump perfused the left ventricle. The left ventricular pressure was maintained at 250 mm Hg. Morphological assessment of the loop reconstruction was performed using an endoscope.

Results

10 independent chordal reconstructions were performed. In all cases, the loop unit remained anchored against pressures exceeding 250 mm Hg. Upon increasing the water filling volume, rupture of a chorda tendinea occurred in 7 cases, rupture of the papillary muscle occurred in 2 cases, and left ventricle rupture occurred in 1 case. In all rupture cases, the loop unit remained anchored to the papillary muscle.

Conclusion

This dynamic evaluation of the loop technique using U-Clips to anchor the loop unit to a papillary muscle showed that the loop technique using U-Clips is a safe method.

Outcomes of mitral valve repair using artificial chordae

OBJECTIVES

The use of artificial chordae techniques has increased the number of mitral valve lesions which are amenable to repair. Artificial chordae can be adapted for a wide range of mitral valve pathologies including restricting the motion of overly mobile 'floppy' Barlow disease leaflets, replacing diseased chordae and improving coaptation in degenerative disease. There is continuing concern about the long-term performance of artificial chordae, which become endothelialized over time and may exhibit complications during the early or late follow-up period.

METHODS

To address these issues, we reviewed the literature and extracted 17 papers reporting outcomes following artificial chordae replacement. We discuss the evidence of the effect of artificial chordae on mortality, morbidity and valve performance as measured by echocardiography and complications related to the chordae. We discuss in detail studies comparing artificial chordae with more widely used quadrangular resection techniques.

RESULTS

In general, outcomes with respect to mortality, morbidity, rates of reoperation, long-term function and complications of artificial chordae implantation are excellent in a range of pathological settings and in both children and adults. These results are comparable with classical Carpentier techniques and there is some evidence that chordal replacement techniques can in some respects improve the risk-benefit ratio for outcomes compared with the classical Carpentier techniques.

CONCLUSIONS

A number of problems remain in the use of artificial chordae, especially the proper determination of their length. Techniques that solve these issues may enhance patient outcomes further.

Artificial chordae for degenerative mitral valve disease: critical analysis of current techniques

The surgical repair of degenerative mitral valve disease involves a number of technical points of importance. The use of artificial chordae for the repair of degenerative disease has increased as a part of the move from mitral valve replacement to repair of the mitral valve. The use of artificial chordae provides an alternative to the techniques pioneered by Carpentier (including the quadrangular resection, transfer of native chordae and papillary muscle shortening/plasty), which can be more technically difficult. Despite a growth in their uptake and the indications for their use, a number of challenges remain for the use of artificial chordae in mitral valve repair, particularly in the determination of the correct length to ensure optimal leaflet coaptation. Here, we analyse over 40 techniques described for artificial chordae mitral valve repair in the setting of degenerative disease.

Ocular biocompatibility of nitinol intraocular clips

PURPOSE

To evaluate the tolerance and biocompatibility of a preformed nitinol intraocular clip in an animal model after anterior segment surgery.

METHODS

Yucatan mini-pigs were used. A 30-gauge prototype injector was used to attach a shape memory nitinol clip to the iris of five pigs. Another five eyes received conventional polypropylene suture with a modified Seipser slip knot. The authors compared the surgical time of each technique. All eyes underwent standard full-field electroretinogram at baseline and 8 weeks after surgery. The animals were euthanized and eyes collected for histologic analysis after 70 days (10 weeks) postsurgery. The corneal thickness, corneal endothelial cell counts, specular microscopy parameters, retina cell counts, and electroretinogram parameters were compared between the groups. A two sample t-test for means and a P value of 0.05 were use for assessing statistical differences between measurements.

RESULTS

The injection of the nitinol clip was 15 times faster than conventional suturing. There were no statistical differences between the groups for corneal thickness, endothelial cell counts, specular microscopy parameters, retina cell counts, and electroretinogram measurements.

CONCLUSIONS

The nitinol clip prototype is well tolerated and showed no evidence of toxicity in the short-term. The injectable delivery system was faster and technically less challenging than conventional suture techniques.

Minimally invasive robotic mitral valve surgery

Over the past two decades, significant advances have been made in mitral valve surgery. Cardiac surgeons have successfully repaired degenerative and ischemic regurgitant mitral valves via a traditional midline sternotomy. In recent years, alternate incisions have yielded minimally invasive approaches to the mitral valve. Technological advances have made robotically assisted minimally invasive mitral valve surgery feasible. Decreased pain, more rapid return to work, diminished blood loss and reduced length of hospitalization have been witnessed following robotic mitral valve surgery when compared with a traditional sternotomy. Equivalent long-term mortality and freedom from recurrent mitral regurgitation are evident between mitral valve repair performed via a traditional sternotomy and minimally invasive and robotic techniques. As a result, an increasing number of patients and referring cardiologists are seeking minimally invasive approaches to mitral valve surgery.

Different ways to repair the mitral valve with artificial chordae: a systematic review

Myxomatous mitral regurgitation (type II Carpentier's functional classification) affects about 1-2% of the population. This represents a very common indication for valve surgery resulting in a low percentage of repairs compared to replacement which is actually performed. In the last decades, several methods for mitral valve repair have been developed, to make the surgical feasibility easier, improve the long-term follow-up thus avoiding the need for reoperations. A very interesting method is represented by the combination of various valve repair techniques, depending on the involvement of the anterior, posterior, or both leaflets, and the use of PTFE artificial chordae tendineae when excessive chordal elongation or rupture due to myxomatous degeneration co-exists. The aim of this review is to summarize the evolution of these techniques from the beginning till now.