Sutureless aortic valve replacement: an alternative to transcatheter aortic valve implantation?

Semiautonomous Robotic Manipulator for Minimally Invasive Aortic Valve Replacement

Aortic valve surgery is the preferred procedure for replacing a damaged valve with an artificial one. The ValveTech robotic platform comprises a flexible articulated manipulator and surgical interface supporting the effective delivery of an artificial valve by teleoperation and endoscopic vision. This article presents our recent work on force-perceptive, safe, semiautonomous navigation of the ValveTech platform prior to valve implantation. First, we present a force observer that transfers forces from the manipulator body and tip to a haptic interface. Second, we demonstrate how hybrid forward/inverse mechanics, together with endoscopic visual servoing, lead to autonomous valve positioning. Benchtop experiments and an artificial phantom quantify the performance of the developed robot controller and navigator. Valves can be autonomously delivered with a 2.0±0.5 mm position error and a minimal misalignment of 3.4±0.9°. The hybrid force/shape observer (FSO) algorithm was able to predict distributed external forces on the articulated manipulator body with an average error of 0.09 N. FSO can also estimate loads on the tip with an average accuracy of 3.3%. The presented system can lead to better patient care, delivery outcome, and surgeon comfort during aortic valve surgery, without requiring sensorization of the robot tip, and therefore obviating miniaturization constraints.

Perceval S valve empire: healing the Achilles' heel of sutureless aortic valves

Aortic valve replacement is the treatment of choice concerning aortic valve disease. Excellent short- and longterm clinical results are reported. Patients referred for aortic valve replacement are getting older and older, so bioprosthetic valves play a more central role worldwide. However, patient comorbidities are also increased more often rendering patients unsuitable for open conventional aortic valve replacement. As a result, transcatheter aortic valve implantation has become the treatment of choice in patients at very high surgical risk. However, the percutaneous technique is related to major disadvantages provided that the diseased native valve is left in place. Its durability is also uncertain. More recently, sutureless Perceval S valve bioprosthesis has gained ground in the field of aortic stenosis therapy filling the gap between conventional aortic valve replacement and transcatheter approach. Excellent haemodynamic and clinical results are reported. Its deployment is performed under direct view and ischemic and overall operative times are significantly decreased. Five-year follow-up results are also optimal. However, the "Achilles' heel" of sutureless technology is increased rates of postoperative permanent pacemaker implantation requirement compared to conventional approach. The incidence of this complication varies in literature. Patient-related factors such as preoperative conduction disorders, older age and short membranous septum are predictors of postoperative pacemaker requirement. However, several technical modifications with regard to manufacturer recommendations can be adopted to mitigate this complication. Appropriate annular decalcification, higher guiding sutures placement, reduced balloon pressure and duration and avoiding of oversizing can contribute to prevent from this complication.

ValveTech: A Novel Robotic Approach for Minimally Invasive Aortic Valve Replacement

OBJECTIVE

Aortic valve disease is the most common heart disease in the elderly calling for replacement with an artificial valve. The presented surgical robot aims to provide a highly controllable instrument for efficient delivery of an artificial valve by the help of integrated endoscopic vision.

METHODS

A robot (called ValveTech), intended for minimally invasive surgery (MIS) and consisting of a flexible cable driven manipulator, a passive arm, and a control unit has been designed and prototyped. The flexible manipulator has several features (e.g., stabilizing flaps, tiny cameras, dexterous introducer and custom cartridge) to help the proper valve placement. It provides 5 degrees of freedom for reaching the operative site via mini-thoracotomy; it adjusts the valve and expands it at the optimal position. The robot was evaluated by ten cardiac surgeons following a real surgical scenario in artificial chest simulator with an aortic mockup. Moreover, after each delivery, the expanded valve was evaluated objectively in comparison with the ideal position.

RESULTS

The robot performances were evaluated positively by surgeons. The trials resulted in faster delivery and an average misalignment distance of 3.8 mm along the aorta axis; 16.3 degrees rotational angle around aorta axis and 8.8 degrees misalignment of the valve commissure plane to the ideal plane were measured.

CONCLUSION

The trials successfully proved the proposed system for valve delivery under endoscopic vision.

SIGNIFICANCE

The ValveTech robot can be an alternative solution for minimally invasive aortic valve surgery and improve the quality of the operation both for surgeons and patients.

Safety and Haemodynamic Outcomes of Currently Available Suture-less Aortic Valves in Patients With Aortic Stenosis: A Meta-Analysis

BACKGROUND

Suture-less aortic valves aim to achieve better outcomes and to aid and facilitate the minimally invasive aortic valve replacement procedure by tackling the issue of cross-clamp time, which is an independent predictor of postoperative outcomes, especially in patients with serious comorbidities. By reducing the number of sutures, the time for suture placement is reduced. Our meta-analysis tried to assess the safety and haemodynamic performance of the suture-less aortic valve prostheses to ascertain their benefits as a viable alternative to current established measures.

METHOD

From their inceptions to February 2017, six electronic databases were searched. Relevant studies using commercially accessible suture-free valves to replace the aortic valve have been recognised. Based on the predefined endpoints, data were collected and analysed.

RESULTS

For incorporation in qualitative and quantitative analyses, 24 studies were recognised, with a total number of 5,073 patients undergoing suture-less aortic valve replacement. Mortality incidence at the 30-day and 12-month follow-ups were 2.5% and 2.7%, respectively, while the incidences of thromboembolic events (1.6%) and paravalvular leak (0.5%) were acceptable.

CONCLUSIONS

Current available evidence indicates that sutureless aortic valve replacement is a safe operation showing low mortality and complication rates, with satisfactory haemodynamic performance.

SAVR versus TAVI: What about the Hemodynamic Performance? An In Vivo and In Vitro Analysis

Background Surgical aortic valve replacement (SAVR) is nowadays discussed whether it remains the gold standard of treatment. In the last decade, there has been a tremendous increase in transcatheter aortic valve implantation (TAVI) due to the growing expertise and excellent results of the catheter-based approach. We, therefore, retrospectively compared the rapid deployment valve (RDV), the Edwards Intuity valve (IEV), with the Edwards Sapien 3 (S3V) with regard to post-procedural hemodynamics.

Methods A total of 246 patients treated with TAVI or SAVR between February 2009 and November 2015 were included. One-hundred twenty-five patients were analyzed in the SAVR group and compared with 121 patients undergoing TAVI. Transvalvular pressure gradients (PGs) and the incidence and extent of aortic regurgitation (AR) were compared post-procedurally by echocardiography for each valve size. In vitro hemodynamics were analyzed by placing both valves into an aortic silicone phantom connected to a pulsatile flow pump and measured using phase-contrast magnetic resonance imaging (4D flow MRI).

Results Post-procedurally, mean transvalvular PGs for the 23 mm valves were 9 (7;11.5) versus 13 (9;18) (p < 0.001), whereas maximum PGs were 16.5 (14;22) versus 25.5 mm Hg (17.5;34) (p < 0.001) in IEV and S3V patients, respectively. The 21 mm IEV showed significantly lower transvalvular PGs compared with the 23 mm S3V: mean PGs: 11 (8;13) versus 13 (9;18) (p < 0.05); maximum PG: 19.5 (13;24) versus 25.5 (18;34) mm Hg (p < 0.05). Analysis revealed significantly lower post-procedural transvalvular PGs for larger valves sizes. With respect to AR, the incidence of AR was significantly lower in IEV group (p < 0.05). In vitro velocities and turbulent kinetic energy values showed similar results between both valves.

Conclusion Implanted RDVs presented a lower incidence of paravalvular regurgitation and were associated with significantly lower post-procedural transvalvular PGs, especially for small valve sizes. Our data might support the application of rapid deployment aortic valves in patients with small aortic annulus in the TAVI era.

Rapid-deployment or transcatheter aortic valves in intermediate-risk patients?

Background Transcatheter aortic valve implantation and rapid-deployment aortic valve replacement represent two emerging therapies for patients with intermediate surgical risk and severe aortic stenosis. However, head-to-head comparisons between such novel therapies are lacking. Methods Severe aortic stenosis patients with intermediate surgical risk treated with rapid-deployment valve replacement at our institution were identified and compared with a propensity-matched population of patients who underwent transcatheter aortic valve replacement. Postoperative echocardiographic findings, in-hospital and midterm clinical outcomes were compared. Results We identified 60 patients who received transcatheter ( n = 30) or rapid-deployment ( n = 30) valve replacement. On postoperative echocardiography, freedom from paravalvular regurgitation was higher in the rapid-deployment valve group ( p < 0.001), while postoperative mean transprosthetic gradient was lower in the transcatheter valve group ( p = 0.03). Permanent pacemaker implantation was required more frequently in transcatheter valve patients ( p = 0.01). Postoperative atrial fibrillation was more common in the rapid-deployment valve group ( p = 0.03). Hospital mortality was similarly low in both groups ( p = 0.33). At midterm follow-up, mortality was comparable ( p = 0.42) but the rapid-deployment valve group still had a lower degree of paravalvular regurgitation. Conclusions Transcatheter and rapid-deployment valve replacement are promising treatment options for patients with intermediate surgical risk. These two techniques are associated with specific patterns of prosthesis function and postoperative complications. Further evaluation of the clinical impact of these therapies in this patient population is needed.

Direct and adjusted indirect comparisons of perioperative mortality after sutureless or rapid-deployment aortic valve replacement versus transcatheter aortic valve implantation

OBJECTIVES

To determine which procedure, aortic valve replacement (AVR) with a sutureless or rapid-deployment prosthesis (SL-AVR) or transcatheter aortic valve implantation (TAVI), achieves better perioperative survival for severe aortic stenosis (AS), we conducted direct-comparison meta-analyses (DC-MAs) and an adjusted indirect-comparison meta-analysis (IDC-MA).

METHODS

We searched MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials through April 2016. Eligible studies were randomized controlled trials (RCTs) and propensity-score matched (PSM) studies. We performed a DC-MA-[A] of SL-AVR versus TAVI, a DC-MA-[B] of SL-AVR versus conventional AVR (C-AVR), and a DC-MA-[C] TAVI versus C-AVR. Then, we computed a IDC-MA-[A'] of TAVI versus SL-AVR from the results of the DC-MA-[B] and the DC-MA-[C].

RESULTS

We identified 6 RCTs and 30 PSM studies enrolling a total of 15,887 patients. The 3 DC-MAs demonstrated significantly lower perioperative (30-day or in-hospital) all-cause mortality after SL-AVR than after TAVI (odds ratio [OR], 0.48; 95% confidence interval [CI], 0.28 to 0.80; p=0.005) and no significant differences between SL-AVR and C-AVR (OR, 1.07; 95% CI, 0.60 to 1.94; p=0.81) and between TAVI and C-AVR (1.07; 95% CI, 0.90 to 1.27; p=0.45). The computed IDC-MA-[A'] indicated no significant difference in mortality between SL-AVR and TAVI (1.01; 95% CI, 0.54 to 1.86). Combining the results of the DC-MA-[A] and IDC-MA [A'] showed significantly lower mortality after SL-AVR than after TAVI (OR, 0.65; 95% CI, 0.44 to 0.97; p=0.03).

CONCLUSIONS

For patients with severe AS, SL-AVR may achieve better perioperative survival than TAVI.

Transcatheter aortic valve implantation in degenerative sutureless perceval aortic bioprosthesis

Sutureless aortic bioprostheses (SAB) are increasingly being used to provide shorter cross-clamp time. Valve-in-valve transcatheter aortic valve replacement (VIV-A) is shown to be effective and safe in the vast majority of patients with degenerated bioprosthetics, yet its' use in SAB failure is infrequent. We present a case of balloon-expandable VIV-A in an 80-year-old woman who suffered severe symptomatic aortic regurgitation in a failed Perceval S 21-mm valve. Computed tomography scan demonstrated a deformed valve. Our heart team favored a percutaneous VIV-A over reoperation due to the patients' high surgical risk. An Edwards-Sapien XT 23 mm was successfully deployed with excellent results. The patient remained asymptomatic following 6 months. As other bioprosthesis, some sutureless valves are condemned to structural valve degeneration. Because VIV-A is being established for managing degenerative bioprosthesis in high risk patients, it is cardinal to identify its role in novel degenerative sutureless valves. SAB were introduced to the clinical market only 5-7 years ago. The absence of sutures may theoretically impose risk for valve instability when adding a transcatheter sutureless valve inside the first one. Our successful experience was very reassuring. We report its feasibility because we believe it should provide support for further investigation on VIV-A within novel SAV. © 2016 Wiley Periodicals, Inc.

Surgical sutureless and transcatheter aortic valves: hemodynamic performance and clinical outcomes in propensity score-matched high-risk populations with severe aortic stenosis

OBJECTIVES

In propensity score-matched patients with severe aortic stenosis treated with surgical aortic valve replacement (AVR) with the 3f Enable sutureless prosthesis (Medtronic, Minneapolis, Minnesota) or transcatheter aortic valve replacement (TAVR), the hemodynamic performance of both valves and mid-term survival of patients were evaluated.

BACKGROUND

Data on hemodynamic performance of surgical sutureless bioprostheses in high operative risk patients with aortic stenosis are scarce.

METHODS

Of 258 patients undergoing TAVR or surgical aortic valve replacement with the 3f Enable valve, 80 (79 ± 5 years of age, 100% men) were included in the current analysis on the basis of propensity score 1:1 matching for baseline clinical and hemodynamic characteristics. All patients had hemodynamic echocardiographic evaluation at baseline and discharge. Mid-term survival was analyzed.

RESULTS

Compared with the 3f Enable valve, TAVR prostheses (Edwards SAPIEN XT [Edwards Lifesciences, Irvine, California] and CoreValve [Medtronic]) had larger effective orifice area index (1.00 ± 0.30 cm(2)/m(2) vs. 0.76 ± 0.22 cm(2)/m(2); p < 0.001), lower pressure gradient (8.14 ± 4.21 mm Hg vs. 10.72 ± 4.01 mm Hg; p = 0.006), less frequent prosthesis-patient mismatch (30.0% vs. 67.5%; p = 0.001), and low flow (46.2% vs. 72.5%; p = 0.02), but more frequent aortic regurgitation (87.5% vs. 20.0%; p < 0.001). The presence of prosthesis-patient mismatch was independently associated with a low-flow state at discharge (odds ratio: 4.70; p = 0.004) and independently associated with the use of the sutureless prosthesis (odds ratio: 3.90; p = 0.02). However, the survival of the 2 groups was comparable after 1.5-year (interquartile range: 0.79 to 2.01 years) follow-up (log-rank test, p = 0.95).

CONCLUSIONS

TAVR prostheses demonstrated better hemodynamics than the 3f Enable valve but a higher incidence of aortic regurgitation. However, these differences did not influence mid-term survival of patients.

Sutureless aortic valve replacement: a systematic review and meta-analysis

BACKGROUND

Sutureless aortic valve replacement (SU-AVR) has emerged as an innovative alternative for treatment of aortic stenosis. By avoiding the placement of sutures, this approach aims to reduce cross-clamp and cardiopulmonary bypass (CPB) duration and thereby improve surgical outcomes and facilitate a minimally invasive approach suitable for higher risk patients. The present systematic review and meta-analysis aims to assess the safety and efficacy of SU-AVR approach in the current literature.

METHODS

Electronic searches were performed using six databases from their inception to January 2014. Relevant studies utilizing sutureless valves for aortic valve implantation were identified. Data were extracted and analyzed according to predefined clinical endpoints.

RESULTS

Twelve studies were identified for inclusion of qualitative and quantitative analyses, all of which were observational reports. The minimally invasive approach was used in 40.4% of included patients, while 22.8% underwent concomitant coronary bypass surgery. Pooled cross-clamp and CPB duration for isolated AVR was 56.7 and 46.5 minutes, respectively. Pooled 30-day and 1-year mortality rates were 2.1% and 4.9%, respectively, while the incidences of strokes (1.5%), valve degenerations (0.4%) and paravalvular leaks (PVL) (3.0%) were acceptable.

CONCLUSIONS

The evaluation of current observational evidence suggests that sutureless aortic valve implantation is a safe procedure associated with shorter cross-clamp and CPB duration, and comparable complication rates to the conventional approach in the short-term.

Anterolateral approach for minimally invasive aortic valve replacement

OBJECTIVE

Right anterior thoracotomy is the most common approach of minimally invasive aortic valve replacement (MIAVR) via intercostal mini-thoracotomy. However, there are some disadvantages including sacrificing the right internal thoracic artery (RITA). The aim of the present study was to investigate the efficacy of anterolateral thoracotomy (ALT), which is similar to lateral thoracotomy used for minimally invasive mitral valve surgery, for MIAVR.

METHODS

From October 2012 to June 2013, 21 patients underwent MIAVR through ALT. Perioperative outcome of these patients was compared with those of 59 patients who underwent MIAVR via standard anterior thoracotomy (SAT) from May 2007 to September 2012.

RESULTS

Mean age, body surface area, annular size, the ratio of aortic stenosis, and Japan score (30 days mortality), in ALT group were significantly more severe than those in SAT group. There was no significant difference in operative time; however, cardiopulmonary bypass and cross-clamping times in ALT group were significantly longer than those in SAT group. Significant differences were not found in mortality, morbidity, intubation time, blood transfusion rate, intensive care unit stay, hospital stay, and echocardiographic data such as effective orifice area index between both groups.

CONCLUSIONS

Anterolateral approach has several advantages including no need to sacrifice the RITA and cosmetic benefit in female patients, offering similar results as SAT even with more severe patient characteristics.