Off-pump tricuspid valve repair by automated sutured tricuspid annular plication via transatrial cannulation: preclinical ex vivo and in vivo results

A tissue-silicone integrated simulator for right ventricular pulsatile circulation with severe functional tricuspid regurgitation

There is a great demand for development of a functional tricuspid regurgitation (FTR) model for accelerating development and preclinical study of tricuspid interventional repair devices. This study aimed to develop a severe FTR model by creating a tissue-silicone integrated right ventricular pulsatile circulatory simulator. The simulator incorporates the porcine tricuspid annulus, valve leaflets, chordae tendineae, papillary muscles, and right ventricular wall as one continuous piece of tissue, thereby preserving essential anatomical relationships of the tricuspid valve (TV) complex. We dilated the TV annulus with collagenolytic enzymes under applying stepwise dilation, and successfully achieved a severe FTR model with a regurgitant volume of 45 ± 9 mL/beat and a flow jet area of 15.8 ± 2.3 cm2 (n = 6). Compared to a normal model, the severe FTR model exhibited a larger annular circumference (133.1 ± 8.2 mm vs. 115.7 ± 5.5 mm; p = 0.009) and lower coaptation height (6.6 ± 1.0 mm vs. 17.7 ± 1.3 mm; p = 0.003). Following the De-Vega annular augmentation procedure to the severe FTR model, a significant reduction in regurgitant volume and flow jet area were observed. This severe FTR model may open new avenues for the development and evaluation of transcatheter TV devices.

Evaluation of a Novel Automated Suturing Technology for Mitral Chordal Implantation: 1-Year Results

PURPOSE

A new automated expanded polytetrafluoroethylene (ePTFE) suture placement device and a new customized titanium fastener deployment device were clinically evaluated in open and less-invasive mitral valve repair (MVr).

DESCRIPTION

Twelve patients were monitored for 1 year after undergoing MVr using the study devices. The study end points included surgical outcomes, operative times, valve repair durability, adverse events, and mortality.

EVALUATION

Three patients received 1 ePTFE chord using the study technology, and 9 patients received 2 chords. Mitral regurgitation at 30 days was absent in 8 patients, trace in 2, and mild in 2. At the 1-year follow-up, mitral regurgitation was absent in 7 patients, trace in 2, mild in 2, and moderate in 1. There were no replacement chord failures, reoperations, or death.

CONCLUSIONS

The initial outcomes of new automated ePTFE suture placement and titanium fastener deployment devices encourage further clinical evaluations.

Morphometric Characterization of an Ex Vivo Porcine Model of Functional Tricuspid Regurgitation

Emerging treatments for tricuspid valve (TV) regurgitation require realistic TV pathological models for preclinical testing. The aim of this work was to investigate structural features of fresh and defrosted porcine right-heart samples as models of mild and severe functional tricuspid regurgitation (FTR) condition in ex-vivo pulsatile flow platform. Ten fresh hearts were tested ex-vivo under steady and pulsatile flow in typical right-heart loading conditions. Hemodynamics and 3D echocardiographic imaging of TV and right ventricle (RV) were acquired. Hearts were then kept frozen for 14 days, defrosted, and tested again with the same protocol. Morphometric parameters of TV and RV were derived from 3D reconstructions based on echo data. Fresh samples showed a slightly dilated TV morphology, with coaptation gaps among the leaflets. Sample freezing induced worsening of TV insufficiency, with significant (p < 0.05) increases in annulus size (annulus area and perimeter 7.7-3.1% respectively) and dilation of RV (9.5%), which led to an increase in tenting volume (123.7%). These morphologic alterations reflected into a significant increment of regurgitation fraction (27%). Together, such results suggest that fresh porcine heart samples may be a reliable ex-vivo model of mild FTR condition, which can be enhanced through freezing/thawing treatment to model a severe pathological condition.

Novel Automated Suturing Technology for Minimally Invasive Mitral Chord Implantation: A Preclinical Evaluation Study

OBJECTIVE

This study evaluated the ergonomics and time requirements of using a novel automated suturing and titanium fastener deployment technology for chordal replacement in human heart specimens in open and minimally invasive cardiac surgery (MICS) simulators.

METHODS

Five cardiac surgeons used novel, manually powered expanded polytetrafluoroethylene (ePTFE) suturing devices to automate suture placement between mitral leaflets and papillary muscles in explanted cadaver hearts, along with customized titanium fastener delivery devices to secure suture and trim suture tails. This mitral chordal replacement test was conducted using surgical models simulating open and MICS mitral repair access. The study was approved by the institutional ethical board.

RESULTS

After a brief introduction to this technique using plastic models, study surgeons performed 48 chordal replacements in human mitral valves, placing 18 in an open model and 30 in a right minithoracotomy model. The time range to complete a single chordal replacement was between 55 s and 8 min, with an overall mean duration of 3.6 ± 1.5 min. No difference in duration of implantation was recorded for the MICS and open sternotomy simulators used. Good control of suture delivery was reported in 95.8% (n = 46) of leaflet aspect of the sutures and in 100% (N = 48) of papillary muscle sutures.

CONCLUSIONS

Automated mitral chordal ePTFE suturing simulated through open and MICS access demonstrated quality handling and accurate placement of sutures in human heart specimens. A clinical trial using this technology is currently ongoing. This innovation may present an important advance facilitating enhanced minimally invasive mitral valve repair.

Beating vs Arrested Heart Isolated Tricuspid Valve Surgery: Long-term Outcomes

BACKGROUND

Isolated tricuspid valve (TV) surgery is a rare procedure generally considered at high risk of perioperative mortality and poor long-term outcomes. Surgical treatment can be performed with either an arrested heart (AH) or beating heart (BH) technique. Aim of this study is to compare the outcomes of isolated tricuspid surgery with two different approaches.

METHODS

The SUR-TRI study is a multicenter international retrospective study enrolling adult patients who underwent isolated tricuspid valve procedures (n=406, 56±16 years; 56% female) at 13 international sites. AH and BH strategies were performed in 253 and 153 cases, respectively. Propensity score-matched analysis was used to compare groups.

RESULTS

After matching, 129 pairs were obtained and analyzed. The 30-day mortality rate was 6.2 vs 5.0% in the AH and BH groups, respectively (p=0.9). The rates of acute renal failure requiring replacement therapy (3 vs 10%, p=0.02) and stroke (0 vs 1.8%, p=0.08) were numerically higher in the AH group. The 6-year survival rate was 67±6 vs 78±5% in the AH and BH groups, respectively (p=0.18), while freedom from cardiac death was 75±5 vs 84±4% (p=0.21). The six-year composite cardiac endpoint of cardiac death and reoperation rate was 60±9 vs 86±5% (p=0.024) comparing AH-TV replacement and BH-TV repair groups.

CONCLUSIONS

Isolated tricuspid valve surgery performed with a beating heart strategy is a safe option and resulted in a trend of increased long-term survival and freedom from reoperation when compared with the standard arrested heart technique. Patients undergoing beating heart valve repair had the best long-term outcome.