Comparative differences of mitral valve-in-valve implantation: A new mitral bioprosthesis versus current mosaic and epic valves.

OBJECTIVE: Evaluate transcatheter mitral valve replacement (TMVR) valve-in-valve (VIV) outcomes in three different mitral bioprostheses (of comparable measured internal diameters) under stable hemodynamic and surgical conditions by bench, echocardiographic, computerized tomography (CT), and autopsy comparisons pre- and post-valve implantation in a porcine model under matched controlled conditions. BACKGROUND: Impact of surgical bioprosthesis design on TMVR VIV procedures is unknown. METHODS: Fifteen similar-sized Yorkshire pigs underwent pre-procedural CT screening. Twelve had consistent anatomic features and underwent implantation of mitral bioprostheses. Four valves from each of three manufacturers were implanted in randomized fashion: 27-mm Epic, 27-mm Mosaic, and 25-mm Mitris, followed by TMVR VIV with 26 Edwards Sapien3. Post-VIV, suprasternal TEE studies were performed to assess hemodynamic function, followed by a gated contrast CT. After euthanasia, animals underwent necropsy for anatomic evaluation. RESULTS: All 12 animals had successful VIV implantation with no study deaths. The post vivMitris (3.77 ± 0.36)/(2.2 ± 0.25 mmHg) had the lowest peak/mean trans-mitral gradient and the vivEpic the highest (15.5 ± 2.55)/(7.09 ± 1.13 mmHg). All THVs (transcatheter heart valves) had greatest deformation within the center of the THV frame; with the smallest waist opening area in the vivEpic (329 ± 35.8 mm2 ) and greatest in the vivMitris (414 ± 33.12 mm2 ). Bioprosthetic frames without obvious radiopaque markers resulted in the most ventricular implantation of the THV's anteroseptal frame (Epic: -4.52 ± 0.76 mm), versus the most radiopaque bioprosthesis (Mitris: -1.18 ± 2.95 mm), and higher peak LVOT gradients (Epic: 4.82 ± 1.61 mmHg; Mitris: 2.91 ± 1.47 mmHg). CONCLUSIONS: The current study demonstrates marked variations in hemodynamics, THV opening area, and anatomic dimensions among measured similarly sized mitral bioprostheses. These data suggest a critical need for understanding the potential impact of variations in bioprosthesis design on TMVR VIV clinical outcomes.

Initial in-human experience with the conveyor cardiovascular system for the delivery of large profile transcatheter valve devices.

OBJECTIVES: To determine the safety and efficacy of the conveyor cardiovascular system (CCS) to facilitate the delivery of large profile transcatheter valve devices. BACKGROUND: Transcatheter valve devices rely on force provided by the operator to be delivered to their intended position. This delivery may be challenging in a variety of anatomic scenarios. The ability to provide steering from the tip of the device by forming an arterial venous loop may help overcome these challenges. METHODS: Between May, 2019 and October, 2020, five patients were recruited for delivery of transcatheter valve devices with the CCS. These patients were deemed by the operators to have challenging anatomy which could make conventional valve delivery difficult or impossible. These patients were recruited as part of an FDA approved early feasibility study or through an institutional review board approved compassionate use protocol. RESULTS: Three patients underwent transcatheter mitral valve replacement with a SAPIEN-3 valve. One patient each underwent transcatheter aortic valve (TAVR) implantation with a SAPIEN 3 and 1 patient underwent TAVR implantation with a Lotus valve. All patients underwent successful implantation of the valve and removal of the CCS and valve delivery systems. There was no more than trivial mitral regurgitation post procedure in any patient and there was no more than trivial paravavular leak. There were no major in-hospital complications. CONCLUSIONS: The CCS facilitates the delivery of large profile transcatheter valve devices in challenging anatomic scenarios. Further studies are needed with additional valve technologies.

Comparison of a new bioprosthetic mitral valve to other commercially available devices under controlled conditions in a porcine model.

BACKGROUND/AIM: To evaluate three mitral bioprostheses (of comparable measured internal diameters) under controlled, stable, hemodynamic and surgical conditions by bench, echocardiographic, computerized tomography and autopsy comparisons pre- and postvalve implantation. METHODS: Fifteen similar-sized Yorkshire pigs underwent preprocedural computerized tomography anatomic screening. Of these, 12 had consistent anatomic features and underwent implantation of a mitral bioprosthesis via thoracotomy on cardiopulmonary bypass (CPB). Four valves from each of three manufacturers were implanted in randomized fashion: 27-mm Epic, 27-mm Mosaic, and 25-mm Mitris bioprostheses. After CPB, epicardial echocardiographic studies were performed to assess hemodynamic function and define any paravalvular leaks, followed by postoperative gated contrast computerized tomography. After euthanasia, animals underwent necropsy for anatomic evaluation. RESULTS: All 12 animals had successful valve implantation with no study deaths. Postoperative echocardiographic trans-valve gradients varied among bioprosthesis manufacturers. The 25-mm Mitris (5.1 ± 2.7)/(2.6 ± 1.3 torr) had the lowest peak/mean gradient and the 27-mm Epic bioprosthesis had the highest (9.2 ± 3.7)/(4.6 ± 1.9 torr). Surgical valve opening area (SOA) varied with the 25-mm Mitris having the largest SOA (2.4 ± 0.15 cm2 ) followed by the 27-mm Mosaic (2.04 ± 0.23 cm2 ) and the 27-mm Epic (1.8 ± 0.27 cm2 ) valve. Bench device orthogonal internal diameter measurements did not match manufacturer device size labeling: 25-mm Mitris (23 × 23 mm), 27-mm Mosaic (23 × 22 mm), 27-mm Epic (21 × 21 mm). CONCLUSIONS: Current advertisement/packaging of commercial surgical mitral valves is not uniform. This study demonstrates marked variations in hemodynamics, valve opening area and anatomic dimensions between similar sized mitral bioprostheses. These data suggest a critical need for standardization and close scientific evaluation of surgical mitral bioprostheses to ensure optimal clinical outcomes.

Seasonal Incidence of Emergent Coronary Artery Bypass Grafting Surgery.

BACKGROUND: Emergent coronary artery bypass grafting (CABG) surgery is often required in the case of severe coronary artery disease, which is refractory to traditional management. The objective of our study was to test the hypothesis that there is seasonal variation in the incidence of emergent CABG. METHODS: A sinusoidal logistic regression model was used to analyze operative data at our cardiovascular institute of 270 cases spanning 5939 calendar days. RESULTS: A cyclic peak risk for emergent CABG was observed for late winter (calendar day 66; P = .036). The odds ratios for the 1-, 2- and 3-month window surrounding this peak were 1.8 (95% CI = 0.94-3.5, P = .072), 1.6 (95% CI = 1.06-2.5, P = .024) and 1.4 (95% CI = 0.9-1.8, P = .066), respectively. CONCLUSION: Our results suggest that a seasonal variation may exist in the incidence of patients presenting with severe coronary artery disease requiring emergent CABG. This information is useful in the scheduling of hospital resources and staff. It also provides important etiology clues underlying coronary artery disease that may lead to future interventions or targeted therapies.

Race and survival among diabetic patients after coronary artery bypass grafting.

BACKGROUND: Diabetes is a known predictor of decreased long-term survival after coronary artery bypass grafting (CABG). Differences in survival by race have not been examined. METHODS: A retrospective cohort study was conducted for CABG patients between 1992 and 2011. Long-term survival was compared in patients with and without diabetes and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: Out of the 13,053 patients undergoing CABG, 35% (black n = 1,655; white n = 2,884) had diabetes at the time of surgery. The median follow-up for study participants was 8.2 years. Long-term survival after CABG was similar between black and white diabetic patients (no diabetes, HR = 1.0; white diabetic patients, adjusted HR = 1.5, 95%CI = 1.4-1.6; black diabetic patients, adjusted HR = 1.5, 95%CI = 1.4-1.7). CONCLUSION: A survival disadvantage after CABG was not observed among black versus white diabetic patients in our study.

The effect of preoperative ß-blocker use and race on long-term survival after coronary artery bypass grafting.

OBJECTIVE: To date, racial differences in the long-term survival of coronary artery bypass grafting (CABG) patients who receive preoperative ß-blockers have not been specifically examined. The purpose of this study was to examine the effect of preoperative ß-blockers on long-term survival among black CABG patients and to compare the magnitude of this effect with white patients. DESIGN: A retrospective cohort study. SETTING: A tertiary referral heart hospital. PARTICIPANTS: 13,354 patients undergoing CABG between 1992 and 2011. MEASUREMENTS AND MAIN RESULTS: Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. A total of 1,448 (62%) black and 6,094 (55%) white patients had a history of preoperative ß-blocker use. Among black patients, those receiving ß-blockers survived longer than those not receiving ß-blockers (adjusted HR = 0.77, 95% CI = 0.67-0.88). The survival advantage was comparable to that observed among white patients (adjusted HR = 0.88, 95% CI = 0.82-0.93). CONCLUSION: Black CABG patients benefited from preoperative ß-blockers and the magnitude of the effect was comparable to that among white patients.

Operative status and survival after coronary artery bypass grafting.

BACKGROUND: The effect of race on long-term survival of patients undergoing elective and nonelective coronary artery bypass grafting (CABG) is currently unknown. The purpose of this study was to compare long-term survival between black and white CABG patients by operative status. METHODS: Long-term survival of black versus white patients undergoing elective and nonelective CABG procedures between 1992 and 2011 was compared. Survival probabilities were computed using the Kaplan-Meier product-limit method and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: A total of 13,774 patients were included in this study. The median follow-up time for study participants was 8.2 years. Black patients undergoing elective CABG died sooner than whites (adjusted HR = 1.4, 95% CI = 1.2-1.5). Survival was similar between blacks and whites in the nonelective population (adjusted HR = 1.0, 95% CI = 0.96-1.1). CONCLUSIONS: Black race was a statistically significant predictor of long-term survival after elective but not nonelective CABG.

Impact of race and postoperative atrial fibrillation on long-term survival after coronary artery bypass grafting.

BACKGROUND AND AIM: Postoperative atrial fibrillation (POAF) is a known predictor of in-hospital morbidity and short-term survival after coronary artery bypass grafting (CABG). The impact of race and long-term survival has not been examined in this population. We aimed to examine the influence of these factors on long-term survival in patients undergoing CABG. METHODS: Patients undergoing first-time, isolated CABG between 1992 and 2011 were included in this study. Long-term survival was compared in patients with and without POAF and stratified by race. Hazard ratios (HR) and 95% confidence intervals (CI) were computed using a Cox regression model. RESULTS: A total of 2,907 (22%) patients developed POAF (black n=370; white n=2,537) following CABG (N=13,165). Median follow-up for study participants was 8.2 years. Long-term survival after CABG differed by POAF status and race (no POAF: HR=1.0; white POAF: adjusted HR=1.1, 95% CI=1.06-1.2; black POAF: adjusted HR=1.4, 95% CI=1.2-1.6; pTrend=0.0002). lack POAF patients also died sooner after surgery than their white counterparts (adjusted HR=1.2, 95% CI=1.02-1.4). CONCLUSION: Black race was a statistically significant predictor of decreased survival among POAF patients after CABG. This finding provides useful outcome information for surgeons and their patients.

Historical evolution of robot-assisted cardiac surgery: a 25-year journey.

Many patients and surgeons today favor the least invasive access to an operative site. The adoption of robot-assisted cardiac surgery has been slow, but now has come to fruition. The development of modern surgical robots took surgeons close collaboration with mechanical, electrical, and optical engineers. Moreover, the necessary project funding required entrepreneurs, federal grants, and venture capital. Non-robotic minimally invasive cardiac surgery paved the way to the application of surgical robots by making changes in operative approaches, instruments, visioning modalities, cardiopulmonary perfusion techniques, and especially surgeons' attitudes. In this article, the serial development of robot-assisted cardiac surgery is detailed from the beginning and through clinical application. Included are references to the historical and most recent clinical series that have given us the evidence that robot-assisted cardiac surgery is safe and provides excellent outcomes. To this end, in many institutions these procedures now have become a new standard of care. This evolution reflects Sir Isaac Newton's famous 1676 quote when referring to Rene Descartes, "If have seen further [sic] than others, it is by standing on the shoulders of giants".

Impact of Anchor Location on Mitral Neochordae Forces: An In Vitro Study.

PURPOSE: This study examined changes in force distribution between the neochordae corresponding to different ventricular anchor locations. DESCRIPTION: Seven porcine mitral valves were mounted in a left heart simulator. Neochordae (expanded polytetrafluoroethylene) originated from either a simulated left ventricular apex, papillary muscle base, or papillary muscle tip location. The neochordae were attached at three sites along the P2 leaflet segment: P2Lateral; P2Center, and P2Medial. Mitral regurgitation was induced by cutting posterior leaflet P2 marginal chordae. The forces on each neochord required to restore normal mitral valve coaptation were quantified for different ventricular anchoring origins and leaflet insertion sites. EVALUATION: The results showed that under both normotensive and hypertensive conditions, the force exerted was much higher at P2Center than either P2Lateral or P2Medial, independent of ventricular anchor location. Also, forces on both P2Lateral and P2Medial were not statistically different. CONCLUSIONS: Artificial neochordae treatment for all anchoring locations was effective in correcting induced mitral regurgitation. The P2 central neochordae had a significantly higher force than both lateral neochords under all conditions.

Increased propensity for cell death in diabetic human heart is mediated by mitochondrial-dependent pathways.

Progressive energy deficiency and loss of cardiomyocyte numbers are two prominent factors that lead to heart failure in experimental models. Signals that mediate cardiomyocyte cell death have been suggested to come from both extrinsic (e.g., cytokines) and intrinsic (e.g., mitochondria) sources, but the evidence supporting these mechanisms remains unclear, and virtually nonexistent in humans. In this study, we investigated the sensitivity of the mitochondrial permeability transition pore (mPTP) to calcium (Ca(2+)) using permeabilized myofibers of right atrium obtained from diabetic (n = 9) and nondiabetic (n = 12) patients with coronary artery disease undergoing nonemergent coronary revascularization surgery. Under conditions that mimic the energetic state of the heart in vivo (pyruvate, glutamate, malate, and 100 µM ADP), cardiac mitochondria from diabetic patients show an increased sensitivity to Ca(2+)-induced mPTP opening compared with nondiabetic patients. This increased mPTP Ca(2+) sensitivity in diabetic heart mitochondria is accompanied by a substantially greater rate of mitochondrial H(2)O(2) emission under identical conditions, despite no differences in respiratory capacity under these conditions or mitochondrial enzyme content. Activity of the intrinsic apoptosis pathway mediator caspase-9 was greater in diabetic atrial tissue, whereas activity of the extrinsic pathway mediator caspase-8 was unchanged between groups. Furthermore, caspase-3 activity was not significantly increased in diabetic atrial tissue. These data collectively suggest that the myocardium in diabetic patients has a greater overall propensity for mitochondrial-dependent cell death, possibly as a result of metabolic stress-imposed changes that have occurred within the mitochondria, rendering them more susceptible to insults such as Ca(2+) overload. In addition, they lend further support to the notion that mitochondria represent a viable target for future therapies directed at ameliorating heart failure and other comorbidities that come with diabetes.

Robotic cardiac surgery.

PURPOSE OF REVIEW: To outline current techniques in robotic cardiac surgery and to report the recent results. RECENT FINDINGS: Robot-assisted surgery is the latest iteration toward less-invasive surgical procedures. Cardiac surgeons have slowly adopted robotic techniques into their armamentarium. In particular, robotic mitral valve surgery has evolved over the last decade and become the preferred method of mitral valve repair and replacement at certain specialized centers worldwide because of excellent results. Robotic single-vessel and double-vessel total endoscopic coronary artery bypass grafting procedures have likewise been standardized on the beating and arrested heart. Other cardiac procedures are in various stages of evolution. Results to date have matched the outcomes of major trials for sternotomy-based procedures. In addition, patients may benefit from shorter hospital stays and experience faster return to full activity. SUMMARY: Stepwise progression of robotic technology and procedure development will continue to make robotic operations simpler and more efficient, which will encourage more surgeons to take up this technology and extend the benefits of robotic surgery to a larger patient population. Long-term results are needed to determine whether robotic techniques could become the new standard in cardiac surgery.

Thoracoscopic robot-assisted extended thymectomy in the human cadaver.

METHODS: Thoracoscopic robot-assisted extended thymectomy was performed in a human cadaver. The technique utilized the da Vinci surgical system inserted through the subxiphoid approach with the sternum lifted upward (anteriorly). A small subxiphoid incision and two additional thoracoports were made in the chest wall, and the sternum was lifted by a new lifting retractor system. RESULTS: This method provided sufficient view and working space in the anterior mediastinum. A complete thymectomy was performed with facility. The robotic system provides superior optics and allows for enhanced dexterity. CONCLUSIONS: Minimally invasive robotic-assisted thymectomy is an effective procedure and may add benefits for both surgeon and patients.

Reoperative, transapical off-pump neochordae implantation for recurrent degenerative mitral regurgitation resulting from a newly ruptured native chord.

Transapical mitral valve repair with NeoChord implantation is effective and safe to replace ruptured chordae due to degenerative disease. Redo transapical neochordae implantation has never been reported in the literature. We present a case report of a 53-year-old man who underwent a reoperative neochord implantation for recurrent severe mitral regurgitation, resulting from degenerative disease progression with a new native chordal rupture. We report the midterm durability of reoperative Neochord repair.

The EACTS simulation-based training course for endoscopic mitral valve repair: an air-pilot training concept in action.

OBJECTIVES: We have developed a high-fidelity minimally invasive mitral valve surgery (MIMVS) simulator that provides a platform to train skills in an objective and reproducible manner, which has been incorporated in the European Association for Cardiothoracic Surgery (EACTS) endoscopic mitral valve repair course. The aim of the study is to provide data on the application of simulation-based training in MIMVS using an air-pilot training concept. METHODS: The 2-day EACTS endoscopic mitral training course design was based on backwards chaining, pre- and post-assessment, performance feedback, hands-on training on MIMVS, theoretical content and follow-up. One hundred two participants who completed the full programme throughout 2016-2018 in the EACTS endoscopic mitral training courses were enrolled in the current study. RESULTS: Of the 102 participants, 83 (83.3%) participants were staff/attending surgeons, 12 (11.8%) participants had finished residency and 5 (4.9%) participants were residents. Theoretical pre- and post-assessment showed that participants scored significantly higher on post-assessment (median score 58% vs 67%, P < 0.001). Pre- and post-assessment of skills on MIMVS showed that participants could work with long-shafted instruments more accurately (suture accuracy 43% vs 99%, P < 0.001) and faster (87 vs 42 s, P < 0.001). Follow-up, based on course evaluation and a survey, had a response rate of 55% (57 participants). Of all surveyed participants, 33.3% (n = 19) had started an endoscopic mitral programme successfully, while 66.7% (n = 38) did not yet start. CONCLUSIONS: The MIMVS is a valuable tool for the development and assessment of endoscopic mitral repair skills. This EACTS course provides surgeons with theoretical knowledge and necessary skills to start an endoscopic mitral valve programme successfully.

Thoracoscopic robot-assisted extended thymectomy in human cadaver.

Thoracoscopic robot-assisted extended thymectomy was performed in a human cadaver. The technique utilized the da Vinci surgical system inserted through the subxiphoid approach with the sternum lifted upward (anteriorly). A small subxiphoid incision and two additional thoracoports were made in the chest wall, and the sternum was lifted by a new lifting retractor system. This method provided sufficient view and working space in the anterior mediastinum. Complete thymectomy was performed with facility. The robotic system provides superior optics and allows for enhanced dexterity. Minimally invasive robotic-assisted thymectomy is an effective procedure and may add benefits for both surgeon and patients.

Port-access atrium retractors for totally endoscopic mitral valve surgery: theTornado Retractor, the Butterfly Retractor, and the Semiautomatic Butterfly Retractor.

INTRODUCTION: We developed three types of new atrial retractors that facilitate totally endoscopic mitral valve surgery. TECHNIQUE: Tornado Retractor: This retractor, which is made of rigid thick wire has a unique appearance, and can be inserted atraumatically through a 3-mm skin incision. Butterfly Retractor: This retractor consists of two parts: a rigid thick rod and foldable blades. When unfolded, the blades have a width of 35 x 55 mm, but they can be inserted thorough the 15-mm thoracoport when folded. Semiautomatic Butterfly Retractor: This retractor has a wired foldable blade and a specially designed rod containing a spring. It can be inserted when closed through the 15-mm thoracoport, and the blades can be opened and fixed automatically after being placed in the thoracic cavity, and the surgeon can remove it through the port easily. These retractors were evaluated in the totally endoscopic robotic mitral valve repairs with human fresh frozen cadavers using the da Vinci Surgical System. CONCLUSION: All the retractors allowed easier access to the heart and provided superior mitral valve presentation without impinging on the robotic arms.

Transient severe mitral regurgitation after mitral valve repair is associated with a poor clinical outcome: a small case series.

BACKGROUND: During mitral valve repair, patients with transesophageal echo-detected immediate postoperative systolic anterior motion of the mitral valve (SAM) and mitral regurgitation (MR) are successfully medically managed. They have been shown to do well in a short-term follow-up. However, the long-term outcome has not been investigated. The objective of this project was to investigate the long-term outcome of these patients. METHODS: This is an observational, retrospective study of 385 patients who underwent MVR. All cases of SAM and MR in this report were successfully medically managed with conservative therapy preventing the need for immediate surgical reintervention. Patients were divided into two groups based on the severity of MR. Group I had grade or= 3+(moderate or severe). Repeat MV surgical procedure or admission to the hospital for congestive heart failure with New York Heart Association (NYHA) Class III or Class IV was identified as a poor outcome. RESULTS: Twelve patients (3.1 %) were identified as having SAM with MR, which was medically managed intraoperatively. Patients were followed an average of 35 months. There were four patients (33.3%) in Group II. None of the eight patients (0%) in Group I had a poor outcome whereas three of the four patients (75%) in Group II had a poor outcome (OR = 3; P value = 0.018). CONCLUSION: These data suggest that despite the immediate improvement in MR and SAM, it is the degree of transient MR that further stratifies patients into good or poor long-term outcomes.

How to do it: importance of left atrial side retraction in robotic and minimally invasive mitral valve surgery.

A customized transthoracic atrial retractor was previously developed for robotic and minimally invasive mitral valve surgery, but it has sometimes failed to provide sufficient exposure of the mitral valve because some atrial tissues push away the operative field from the right side. This report describes 3 new atrial side retractors (the foldaway retractor, the spoon retractor, and the wired retractor) and their use in performing robotic mitral valve repair in fresh frozen human cadavers. These retractors provided exceptional and consistent exposure of the left atrium in robotic and minimally invasive mitral valve surgery in human cadavers without causing traumatic injury, and these retractors should be useful in live patients because they will be used in arrested hearts.