Role of Automated Suturing Technology in Minimally Invasive Aortic and Mitral Valve Surgery.

Minimally invasive cardiac surgery continues to evolve and expand as technology and surgeon experience develops. Among the barriers to the adoption of non-sternotomy minimally invasive valve surgery are the challenges associated with suture placement. Automated technology enables ergonomic remote suture placement that allows for reproducible results while shortening the learning curve. The objective of this review is to describe the latest advancements in automated suturing technology for minimally invasive valve surgery.

A Novel Subxiphoid Approach for Bilateral Internal Thoracic Artery Harvesting.

OBJECTIVE: Bilateral internal thoracic artery (BITA) bypass can enable more complete arterial revascularization procedures. Minimally invasive cardiac surgery (MICS) can offer significant patient benefits. New minimally invasive technology for sternal retraction and tissue manipulation is needed to enable ergonomic and reliable minimally invasive ITA harvesting. The goal of this research was to develop technology and techniques, along with experimental testing and training models, for a sternal-sparing approach to in situ BITA harvesting through a small subxiphoid access site. METHODS: This study focused on optimizing custom equipment and methods for subxiphoid BITA harvesting initially in a porcine model (19 pig carcasses, 36 ITAs) and subsequently in 7 cadavers (14 ITAs). RESULTS: Fifty consecutive ITAs were successfully harvested using this remote access approach. The last 20 ITA specimens harvested from the porcine model were explanted and measured; the average length of the free ITA grafts was 12.8 ± 0.9 cm (range 10.8 to 14.2 cm) with a mean time of 23.3 ± 5.2 minutes (range 13 to 25 minutes) for each harvest. CONCLUSIONS: Early results demonstrate that both ITAs can be reliably harvested in a skeletonized fashion in situ through sternal-sparing, small subxiphoid access in 2 experimental models. This innovative approach warrants further exploration toward facilitating complete arterial revascularization and the further adoption of minimally invasive coronary artery bypass graft surgery.

Interactive translational research model and cadaveric simulation: where minimally invasive cardiac surgery and industry meet.

Focused research targeting an identified clinical problem may result in more rapid development of medical devices, technologies, and surgical techniques that directly impact patient care. These medical advances to improve patient care may be expedited by adopting an interactive translational research model in which inventors, designers, and engineers work in collaboration with surgeons. In addition, cadaveric simulation is a high-fidelity model that is bridging the translational and logistical gap to bring new surgical devices, technologies, and techniques to patients. We describe the partnership between the University of Rochester and LSI SOLUTIONS® in which an interactive translational research model utilizing cadaveric simulation has been successfully applied to accelerate bringing minimally invasive cardiac surgical techniques and innovative devices to patients.

Novel Automated Suturing Technology for Minimally Invasive Aortic Valve Replacements.

PURPOSE: Annular suture placement during minimally invasive right anterior thoracotomy aortic valve replacements (MI-AVR) can be challenging. We present the early clinical experience with novel automated suturing technology that may reduce the technical difficulty of this operation. DESCRIPTION: The technology presented involves an automated articulating suturing device that simultaneously drives dual-curved needles through the aortic annulus to place a pledgeted horizontal mattress suture remotely; a second device with 2 straight needles places suture through the sewing cuff of a prosthetic heart valve. EVALUATION: Automated annular suturing was used in five MI-AVR procedures, which were successfully completed, with no paravalvular leaks detected and a mean aortic valve gradient of 6.4 mm Hg postprocedure. Mean aortic cross-clamp and cardiopulmonary bypass times were 100 and 134 minutes, respectively. All 5 patients were successfully discharged home, with a mean intensive care unit and total length of stay of 2 and 7 days, respectively. CONCLUSIONS: Automated suturing during MI-AVRs is feasible and may reduce the technical challenge of this operation. Further research is necessary to determine its effect on patient outcomes.

A Minimally Invasive Approach for Placing Sew-On Epicardial Leads in the Child.

Traditionally, pacing leads are placed transvenously, although smaller pediatric patients who require permanent pacemakers may benefit from delaying tranvenous lead placement until they are larger. Alternative, minimally invasive atrioventricular pacing options have not previously existed for this patient population, leaving many of these children with large sternotomies or thoracotomies. Using three port sites and an adjustable shaft dual-needle suturing device, we placed a steroid-eluting, sew-on epicardial lead on the right atrium of a 9-year-old patient. This is one of the earliest reported cases of a minimally invasive technique for sew-on epicardial lead placement on the atrium of a child. Although based on a single case, we believe that this approach is safe, reliable, and reproducible and that it can be used to place leads on any aspect of the heart. Adoption of this technique will allow for earlier atrioventricular pacing, which may decrease the incidence of pacemaker syndrome, and thus improve overall outcomes in this patient population.

An Automated Expanded Polytetrafluoroethylene Suturing and Coaxial Fastener System for Mitral Chordae Replacement: Strength, Feasibility, and Healing.

OBJECTIVE: Mitral valve (MV) chordae replacements can be technically challenging. Technology that remotely delivers and accurately secures artificial chordae may reduce the learning curve and improve the reliability of MV repairs. METHODS: The technology involved two devices: a remote suturing device for delivery of expanded polytetrafluoroethylene (ePTFE) suture to the papillary muscle and a Coaxial titanium suture fastener (TF) device with integrated saline infusion for real-time determination of chordae length during fixation. A mechanical model simulating MV chordae tension in a beating heart quantified the durability of 120 coaxially fastened ePTFE sutures using TF over time. Investigation of the technology was performed in ex vivo porcine, ovine, and in situ cadaver hearts, whereas live-tissue testing was conducted in a survivor ovine model. Mitral valve repair procedures involved the iatrogenic induction of mitral regurgitation by the resection of one to two native MV chordae, followed by implantation of ePTFE suture using the technology. Epicardial echocardiography, saline infusion testing, and histologic analysis evaluated MV competence, repair integrity, and long-term healing. RESULTS: Durability testing of ePTFE suture secured with TF demonstrated no degradation of TF pull-apart forces of for 440 million cycles. Mitral valve repairs using the technology were performed in eight sheep; four demonstrating proof of concept and four survived for an average of 6.5 months after completion of the procedure. At reoperation, echocardiography demonstrated trace to no mitral regurgitation with near complete endothelialization of the TF and artificial chordae. CONCLUSIONS: This technology successfully enabled the implantation of artificial chordae while providing real-time adjustment of chordae length during MV repair. These results encourage further investigation of its use clinically.

Prosthetic Aortic Valve Fixation Study: 48 Replacement Valves Analyzed Using Digital Pressure Mapping.

OBJECTIVE: Prostheses attachment is critical in aortic valve replacement surgery, yet reliable prosthetic security remains a challenge. Accurate techniques to analyze prosthetic fixation pressures may enable the use of fewer sutures while reducing the risk of paravalvular leaks (PVL). METHODS: Customized digital thin film pressure transducers were sutured between aortic annulus models and 21-mm bioprosthetic valves with 15 × 4-mm, 12 × 4-mm, or 9 × 6-mm-wide pledgeted mattress sutures. Simulating open and minimally invasive access, 4 surgeons, blinded to data acquisition, each secured 12 valves using manual knot-tying (hand-tied [HT] or knot-pusher [KP]) or automated titanium fasteners (TFs). Real-time pressure measurements and times were recorded. Two-dimensional (2D) and 3D pressure maps were generated for all valves. Pressures less than 80 mm Hg were considered at risk for PVL. RESULTS: Pressures under each knot (intrasuture) fell less than 80 mm Hg for 12 of 144 manual knots (5/144 HT, 7/144 KP) versus 0 of 288 TF (P < 0.001). Pressures outside adjacent sutures (extrasuture) were less than 80 mm Hg in 10 of 60 HT, zero of 60 KP, and zero of 120 TF sites for 15 × 4-mm valves; 17 of 48 HT, 25 of 48 KP, and 12 of 96 TF for 12 × 4-mm valves; and 15 of 36 HT, 17 of 36 KP, and 9 and 72 TF for 9 × 6-mm valves; P < 0.001 all manual versus TF. Annular areas with pressures less than 80 mm Hg ranged from 0% of the sewing-ring area (all open TF) to 31% (12 × 4 mm, KP). The average time per manual knot, 46 seconds (HT, 31 seconds; KP, 61 seconds), was greater than TF, 14 seconds (P < 0.005). CONCLUSIONS: Reduced operative times and PVL risk would fortify the advantages of surgical aortic valve replacement. This research encourages continued exploration of technical factors in optimizing prosthetic valve security.

Comparison of strength, consistency, and speed of COR-KNOT versus manually hand-tied knots in an ex vivo minimally invasive model.

OBJECTIVE: This study compared the strength, consistency, and speed of prosthetic attachment sutures secured with automated fasteners with those of manual knots using an ex vivo porcine mitral valve annuloplasty model. A novel miniature pressure transducer system was developed to quantify pressures between sutured prosthetic rings and underlying cardiac tissue. METHODS: Sixteen mitral annuloplasty rings were sewn into ex vivo pig hearts. Eight rings were secured with the COR-KNOT device; and eight rings, with hand-tied knots using a knot pusher. A cardiac surgeon and a surgery resident each completed four manually tied rings and four COR-KNOT rings via a thoracotomy trainer. The total time to knot and cut each ring's sutures was recorded. Suture attachment pressures were measured within (intrasuture) and between (extrasuture) each suture loop using a 0.5 × 2.0-mm microtransducer probe system. RESULTS: The suture holding pressures for the COR-KNOT fasteners were significantly greater than for the manually tied knots (median, 1008.9 vs 415.8 mm Hg, P < 0.001). All automated fasteners measured greater than 500 mm Hg, whereas 56% of the hand-tied knots were less than 500 mm Hg, and 14% were less than 75 mm Hg. There was less variation in attachment pressures for the COR-KNOT fasteners than for the hand-tied knots (SD, 401.6 vs 499.3 mm Hg, P = 0.04). Significant time savings occurred with the use of the COR-KNOT compared with manual tying (12.4 vs 71.1 seconds per knot, P = 0.001). CONCLUSIONS: The novel microtransducer technology provided an innovative means of evaluating cardiac prosthetic anchoring sutures. In this model, mitral annuloplasty ring sutures secured with the COR-KNOT device were stronger, more consistent, and faster than with manually tied knots.

Healing study of porcine heart transapical wounds closed using a remote automated suturing technology.

OBJECTIVE: A safe and reliable direct percutaneous approach for transapical access to the left ventricle would be a significant advance toward decreasing the invasiveness of intracardiac interventions. This report presents results from a surviving porcine beating heart model in which transapical access sites were closed using an automated suturing technique ultimately intended for percutaneous use. METHODS: Through an approved protocol including general anesthesia, the cardiac apex in 10 beating pig hearts was surgically exposed, permitting transapical passage of a 0.035-in guidewire and a 5.5F, 0.9-mL Fogarty balloon catheter. An automated suturing device was passed over the guidewire and the Fogarty onto the transapical access site. Two pledgeted horizontal mattress sutures were simultaneously placed concentrically around the apical access site with a single squeeze of the device's lever. A 25F dilator was passed into the left ventricle over the guidewire and subsequently removed. The sutures were then secured using pledgeted titanium knots. Chest wall and skin incisions were closed. The animals were recovered from anesthesia and resumed a normal diet. RESULTS: Under general anesthesia, the transapical access site of each animal was re-exposed, five at 1-week and five at 2-week intervals. Hemostasis was complete, and all wounds healed well. CONCLUSIONS: The evaluation of transapical wound closures in this surviving porcine heart model demonstrates complete hemostasis and excellent healing through the use of this automated remote suturing technology.

Automated remote transapical wound closure system study.

PURPOSE: A readily applied and reliable means to create and close transapical wound access sites through a small intercostal opening could benefit many cardiac patients. Using relevant surgical tissue models, this research evaluated a new approach to enable single-port transapical wound site closure toward the eventual development of safe percutaneous access to the left ventricle. DESCRIPTION: Novel techniques and technologies were developed and successfully tested for remote automated placement of 2 pledgeted horizontal mattress sutures delivered concentrically around a transmural apical guidewire, which provided a tract to enable therapeutic intervention. Mechanical pledgeted knots secured these sutures after cannula removal. EVALUATION: Automated transapical closures were created in 47 ex vivo porcine hearts and in 10 human cadavers, 8 through a thoracotomy and 2 thoracoscopically. Automated apical closures achieved hemostasis in an acute beating heart thoracotomy model in 3 anesthetized pigs. An ex vivo porcine heart pressurized infusate model demonstrated the intraventricular pressure tolerated by automated closures (mean, 327 mm Hg) compared with hand-sutured closures (mean, 303 mm Hg). CONCLUSIONS: All automated apical closures were effective. Early results encourage further evaluation.

Natural orifice transluminal endoscopic radical prostatectomy: initial perioperative and pathologic results.

OBJECTIVE: To describe the first clinical experience, pathologic, and perioperative outcomes of natural orifice transluminal endoscopic surgery (NOTES) radical prostatectomy. NOTES represents the evolution of minimally invasive surgery. The conceptual feasibility has been shown in careful laboratory and animal studies, but a scarcity of information regarding clinical applications exists. METHODS: After institutional review board approval, 2 patients agreed to undergo NOTES radical prostatectomy for localized prostate cancer. The prostate was radically resected using a 26F resectoscope, 550-µm laser fiber, and holmium laser. The prostate was delivered into the bladder and removed at the conclusion of the procedure through a suprapubic cystotomy for histopathologic analysis. The vesicourethral anastomosis was completed using a cannula scope, urethral-vesical suturing device, and titanium knot applier. Cystograms were taken immediately postoperatively and at catheter removal. RESULTS: Both patients tolerated the procedure without operative complications. All intraoperative cystograms showed watertight anastomoses. The pathologic examination revealed Gleason score 3 + 3 and Stage pT2aNxMx for 1 patient and Gleason score 3 + 4 and Stage pT2cNxMx for 1 patient, with negative margins for both. No blood transfusions were required. Patient 2 experienced some left-sided gluteal and suprapubic pain postoperatively. CONCLUSION: NOTES radical prostatectomy appears to be a safe and feasible option for the management of carefully selected, organ-confined prostate cancer. The perioperative and pathologic outcomes show promise with this new technique; however, the high standards of oncologic and functional outcomes demand close and longer follow-up before adoption into the surgical armamentarium can be recommended.