Safety of Minimally Invasive Mitral Valve Surgery Without Aortic Cross-Clamp

Minimally Invasive Mitral Valve Surgery Using a Cold Fibrillatory Cardiac Arrest Technique in Patients With Prior Cardiac Surgery

OBJECTIVE

Minimally invasive mitral valve surgery (mini-MVS) is typically reserved for patients who have not undergone open cardiac surgery. In the reoperative setting, using intrapericardial dissection for crossclamping the aorta through a minimally invasive approach can be difficult and, at times, risky. Cold fibrillatory cardiac arrest (CFCA) with systemic cardiopulmonary bypass without cross-clamping is a well-described technique; however, data about its safety for patients who undergo reoperative mini-MVS are limited.

METHODS

Data for 34 patients who underwent reoperative mini-MVS with CFCA from March 2017 to March 2022 were reviewed retrospectively. A mini right thoracotomy (n = 30) or robotic (n = 4) approach was used. Systemic hypothermia was induced to a target temperature of 25 °C.

RESULTS

Patient mean (SD) age was 64.5 (9.6) years, and 15 of 34 (44.1%) patients were women. Of those 34 patients, 23 (67.6%) had severe regurgitation, and 11 (32.4%) had severe stenosis. Before mini-MVS, 28 patients had undergone valve surgery, and 8 had undergone coronary artery bypass graft surgery. The mitral valve was repaired in 5 of 34 (14.7%) and replaced in 29 of 34 (85.3%) patients. No difference was observed in preoperative and postoperative left ventricular function (P = .82). In 1 patient, kidney failure developed that necessitated dialysis. No postoperative stroke or mortality at 30 days occurred.

CONCLUSION

Mini-MVS with CFCA is well tolerated in patients with prior cardiac surgery. Myocardial function was not impaired, nor was the risk of stroke increased in this cohort, indicating that CFCA is a safe alternative in this high-risk population.

A novel interpretative tool for early prediction of low cardiac output syndrome after valve surgery: online machine learning models

OBJECTIVE

Low cardiac output syndrome (LCOS) is a severe complication after valve surgery, with no uniform standard for early identification. We developed interpretative machine learning (ML) models for predicting LCOS risk preoperatively and 0.5 h postoperatively for intervention in advance.

METHODS

A total of 2218 patients undergoing valve surgery from June 2019 to Dec 2021 were finally enrolled to construct preoperative and postoperative models. Logistic regression, support vector machine (SVM), random forest classifier, extreme gradient boosting, and deep neural network were executed for model construction, and the performance of models was evaluated by area under the curve (AUC) of the receiver operating characteristic and calibration curves. Our models were interpreted through SHapley Additive exPlanations, and presented as an online tool to improve clinical operability.

RESULTS

The SVM algorithm was chosen for modeling due to better AUC and calibration capability. The AUCs of the preoperative and postoperative models were 0.786 (95% CI 0.729-0.843) and 0.863 (95% CI 0.824-0.902), and the Brier scores were 0.123 and 0.107. Our models have higher timeliness and interpretability, and wider coverage than the vasoactive-inotropic score, and the AUC of the postoperative model was significantly higher. Our preoperative and postoperative models are available online at http://njfh-yxb.com.cn:2022/lcos.

CONCLUSIONS

The first interpretable ML tool with two prediction periods for online early prediction of LCOS risk after valve surgery was successfully built in this study, in which the SVM model has the best performance, reserving enough time for early precise intervention in critical care.

Minimally Invasive Strategy to Repair Mitral Valve after Repeated Coronary Revascularization: A Case Report and Literature Review

Redo cardiac surgery after Coronary Artery Bypass Grafting (CABG) is burdened by high morbidity and mortality, either intraoperatively and postoperatively, with the repeated sternotomy playing a crucial role as risk factor. The right minithoracotomy approach guarantees a safer control on conduits integrity and the right ventricular wall and a low impact on the respiratory mechanics. Herein, we report a patient who previously underwent two CABG (coronary artery bypass grafting) procedures and who was admitted to the hospital with a picture of heart failure caused by a severe mitral regurgitation. He was successfully submitted to a mitral valve repair on a beating heart via the right minithoracotomy approach.

Ventricular Fibrillatory Arrest: A Safe Option in Robotic Totally Endoscopic Intracardiac Surgery

BACKGROUND

Moderate hypothermic ventricular fibrillatory arrest during heart surgery is an alternative to cardioplegic arrest in selected patients. We reviewed our experience using a ventricular fibrillatory arrest technique in robotic totally endoscopic intracardiac surgery.

METHODS

From February 2014 through July 2022, 128 patients who underwent robotic totally endoscopic intracardiac surgical procedures performed using moderate hypothermic ventricular fibrillatory arrest were reviewed. Patients were chosen based on the risk of aortic manipulation, complexity of the procedure, grade of aortic valve insufficiency and comorbidities, including history of prior cardiac surgery and peripheral vascular disease.

RESULTS

Patients were a mean age of 65 ± 14 years, and the mean The Society of Thoracic Surgeons score was 2.7 ± 2.9. Fourteen patients (11%) had a history of previous cardiac surgery. The intracardiac procedures were mitral valve surgery in 84 patients (66%), isolated cryomaze procedure in 27 (21%), and other in 17 (13%). The mean ventricular fibrillatory arrest time was 79 ± 26 minutes, and the mean cardiopulmonary bypass time was 174 ± 49 minutes. There was no conversion to sternotomy. Seven patients (5.5%) required inotropic support, and 2 patients (1.6%) needed an intra-aortic balloon pump. There was no incidence of postoperative stroke or clinical myocardial infarction. The mean hospital and intensive care unit lengths of stay were 3.1 ± 1.7 and 1.4 ± 0.7 days, respectively. One death (0.78%) occurred due to respiratory failure.

CONCLUSIONS

Moderate hypothermic ventricular fibrillatory arrest in robotic intracardiac surgery may be a safe and effective alternative in selected patients.

Anterior versus posterior leaflet mitral valve repair: A propensity-matched analysis

OBJECTIVE

Mitral valve repair is superior to replacement for degenerative disease, but long-term outcomes of anterior versus posterior leaflet repair remain poorly defined. We propensity matched anterior and posterior repairs to compare long-term outcomes.

METHODS

Patients undergoing first-time degenerative mitral repair between 1992 and 2018 were identified. Primary outcome was overall survival. Secondary outcomes were postprocedural residual mitral regurgitation and reoperation. From 1025 patients, 1:1 propensity score matching was performed, yielding 309 anterior (isolated anterior = 85, bileaflet = 224) and 309 isolated posterior repairs.

RESULTS

Age was 58 ± 15 years, ejection fraction was 57% ± 10%, and matched groups were well balanced. Anterior repairs had longer bypass (122 ± 53 vs 109 ± 43 minutes, P = .001) and crossclamp (94 ± 44 vs 85 ± 62 minutes, P = .033) times. Mean residual mitral regurgitation grade was 0.44 (95% confidence interval, 0.24-0.65) for anterior repair and 0.30 (95% confidence interval, 0.13-0.47) for posterior repair (P = .31). Overall, 92% (569/618) of matched patients had no residual mitral regurgitation, with no differences in mitral regurgitation grade between groups (P = .77). Survival did not differ between anterior (10 years: 72% ± 7%; 15 years: 63% ± 7%) and posterior (10 years: 74% ± 7%; 15 years: 60% ± 8%) groups (log-rank P = .93). Linearized incidence of reoperation was 0.62% per patient-year, including 0.74% for anterior and 0.48% for posterior repairs. Cumulative incidence of reoperation at 15 years was 7.5% after anterior repair and 4.9% after posterior repair (Gray's test P = .26).

CONCLUSIONS

No long-term survival or reoperation difference was found between posterior and anterior repair. On the basis of these findings, surgeons at centers of excellence should aim for repair of both anterior and posterior leaflet pathology with the same decision-making threshold over valve replacement for degenerative mitral disease.

Comparison of robotic and conventional sternotomy in redo mitral valve surgery

BACKGROUND/PURPOSE

Redo operation for mitral valve surgery carries higher risks than first time cardiac surgery. The adhesion between sternum and heart, and also the complexity of second time operation make the redo operation more difficult. The robotic surgery carries some benefit in terms of magnification, assisted by the scope view and precise movement of the instruments. We compared the results of our robotic redo mitral valve surgeries with those of conventional re-sternotomy.

METHODS

Medical records of patients who underwent redo mitral valve surgeries between 2012 and 2019 at our hospital were retrospectively analyzed. Demographic data, patients' medical histories, presenting symptoms, image analyses, echocardiogram data, operative procedures and postoperative clinical outcomes were collected through chart review.

RESULTS

A total of 67 redo mitral valve surgeries, including 23 robotic and 44 re-sternotomy procedures were performed. There were no differences in age, previous operation times, and intervals to previous surgery. Comorbidities of both groups were similar. There was no surgical mortality in the robotic group, and it was 9.0% in the re-sternotomy group (p = 0.287). Operation time was shorter in the robotic group (176 vs. 321 min; robotic vs. re-sternotomy, p＝0.0279). Blood transfusion was lower in the robotic group (1 vs. 2 units; robotic vs. re-sternotomy, p = 0.01189). The ventilation time, ICU stay time, and recheck bleeding rate were similar in both groups.

CONCLUSIONS

In select patients, robotic redo mitral valve surgery is safe and feasible. It could offer low operative mortality. It is associated with shorter operative times, than re-sternotomy and provides equal immediate operative results.

Mitral valve surgery: current status and future prospects of the minimally invasive approach

Introduction: During the past five years the approach to procedural planning, operative techniques and perfusion strategies for minimally invasive mitral valve surgery (MIMVS) has evolved. With the goal to provide a maximum of patient safety the procedure has been modified according to individual patient characteristics and is largely based on preoperative imaging.Areas covered: In this review article we describe the important factors in image based therapy planning and simulation, different access strategies, the operative key-steps, a rationale use of devices, and highlight a few future developments in the field of MIMVS. Published studies were identified through pearl growing, citation chasing, a search of PubMed using the systematic review methods filter, and the authors' topic knowledge.Expert opinion: With the help of expert teams including surgeons specialized in mitral repair, anesthesiologists and perfusionists a broad spectrum of mitral valve pathologies and related pathologies can be treated with excellent functional outcomes. Avoiding procedure related complications is the key for success for any MIMVS program.

Mitral valve disease--current management and future challenges

The field of mitral valve disease diagnosis and management is rapidly changing. New understanding of disease pathology and progression, with improvements in and increased use of sophisticated imaging modalities, have led to early diagnosis and complex treatment. In primary mitral regurgitation, surgical repair is the standard of care. Treatment of asymptomatic patients with severe mitral regurgitation in valve reference centres, in which successful repair is more than 95% and surgical mortality is less than 1%, should be the expectation for the next 5 years. Transcatheter mitral valve repair with a MitraClip device is also producing good outcomes in patients with primary mitral regurgitation who are at high surgical risk. Findings from clinical trials of MitraClip versus surgery in patients of intermediate surgical risk are expected to be initiated in the next few years. In patients with secondary mitral regurgitation, mainly a disease of the left ventricle, the vision for the next 5 years is not nearly as clear. Outcomes from ongoing clinical trials will greatly inform this field. Use of transcatheter techniques, both repair and replacement, is expected to substantially expand. Mitral annular calcification is an increasing problem in elderly people, causing both mitral stenosis and regurgitation which are difficult to treat. There is anecdotal experience with use of transcatheter valves by either a catheter-based approach or as a hybrid technique with open surgery, which is being studied in early feasibility trials.

Preoperative planning of left-sided valve surgery with 3D computed tomography reconstruction models: sternotomy or a minimally invasive approach?

OBJECTIVES

With the emergence of a new concept aimed at individualization of patient care, the focus will shift from whether a minimally invasive procedure is better than conventional treatment, to the question of which patients will benefit most from which technique? The superiority of minimally invasive valve surgery (MIVS) has not yet been proved. We believe that through better patient selection advantages of this technique can become more pronounced. In our current study, we evaluate the feasibility of 3D computed tomography (CT) imaging reconstruction in the preoperative planning of patients referred for MIVS.

METHODS

We retrospectively analysed all consecutive patients who were referred for minimally invasive mitral valve surgery (MIMVS) and minimally invasive aortic valve replacement (MIAVR) to a single surgeon in a tertiary referral centre for MIVS between March 2014 and 2015. Prospective preoperative planning was done for all patients and was based on evaluations by a multidisciplinary heart-team, an echocardiography, conventional CT images and 3D CT reconstruction models.

RESULTS

A total of 39 patients were included in our study; 16 for mitral valve surgery (MVS) and 23 patients for aortic valve replacement (AVR). Eleven patients (69%) within the MVS group underwent MIMVS. Five patients (31%) underwent conventional MVS. Findings leading to exclusion for MIMVS were a tortuous or slender femoro-iliac tract, calcification of the aortic bifurcation, aortic elongation and pericardial calcifications. Furthermore, 2 patients had a change of operative strategy based on preoperative planning. Seventeen (74%) patients in the AVR group underwent MIAVR. Six patients (26%) underwent conventional AVR. Indications for conventional AVR instead of MIAVR were an elongated ascending aorta, ascending aortic calcification and ascending aortic dilatation. One patient (6%) in the MIAVR group was converted to a sternotomy due to excessive intraoperative bleeding. Two mortalities were reported during conventional MVS. There were no mortalities reported in the MIMVS, MIAVR or conventional AVR group.

CONCLUSIONS

Preoperative planning of minimally invasive left-sided valve surgery with 3D CT reconstruction models is a useful and feasible method to determine operative strategy and exclude patients ineligible for a minimally invasive approach, thus potentially preventing complications.

Minimally invasive mitral valve surgery without aortic cross-clamping and with femoral cannulation is not associated with increased risk of stroke compared with traditional mitral valve surgery: a propensity score-matched analysis

OBJECTIVES

Open-heart surgery with fibrillatory arrest has been reported to be associated with an increased risk of stroke. We examined whether minimally invasive mitral valve surgery with fibrillatory arrest conferred a higher risk of stroke/transient ischaemic attack (TIA) and other major complications compared with median sternotomy and cardioplegic arrest.

METHODS

Data were collected prospectively for 387 patients who had mitral valve surgery; 239 had a minimally invasive surgical approach and 148 had median sternotomy. All minimally invasive surgeries were performed by surgeons who were experienced in minimally invasive techniques. The effect of operative approach on risk of stroke/TIA and major morbidity was examined. After propensity score matching (PSM) was conducted between the two groups, 76 patients remained in each group.

RESULTS

Before matching, the incidence of stroke/TIA did not differ between patients who had minimally invasive surgery (0.5%, n = 1) and those who had median sternotomy (1.4%, n = 2; P = 0.56). Patients who had minimally invasive surgery had a lower incidence of other major morbidity (0.8%, n = 2) than patients who had median sternotomy (6.1%, n = 9; P = 0.004). After adjustment for age and Society of Thoracic Surgeons predicted risk, there was no effect of operative approach on the odds for stroke/TIA (odds ratio [OR] = 0.41, P = 0.49) or other major morbidity (OR = 0.40, P = 0.31). After PSM, patients were balanced on preoperative characteristics. No patient in either matched group experienced permanent stroke/TIA, and major morbidity did not differ between the two groups (minimally invasive, 1.3%, n = 1; median sternotomy, 1.3%, n = 1; P > 0.99).

CONCLUSIONS

A minimally invasive approach for mitral valve surgery on a fibrillating heart was not associated with a greater incidence of stroke/TIA than was median sternotomy. When performed by highly experienced surgeons, the minimally invasive approach with fibrillatory arrest did not increase the risk of perioperative stroke.

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.

Safeguards and pitfalls in minimally invasive mitral valve surgery

Minimally invasive mitral valve surgery has been established in many institutions worldwide. Appropriate indications and patient selection for this procedure must be based on a thorough understanding of its limitations and specific pitfalls. Particular risks can be minimized with careful attention to detail when planning and performing the surgery. The following chapter offers a stepwise description of the procedure; we point out particular advantages, discuss our rationale for certain steps, as well as focus on potential dangers of minimally invasive mitral valve surgery. Several graphics have also been provided to illustrate our approach and demonstrate important structural and anatomical concepts of the mitral valve apparatus.

Two approaches for repeat cardiac surgery

BACKGROUND

With recent advances in post-operative care and surgical methods, the number of cardiovascular re-operations is increasing. We analyzed our institutional experience to evaluate the safety and efficacy of the approach methods for cardiac re-operations.

METHODS

Between September 2007 and December 2010, we performed 208 cardiac re-operations, defined as surgery which was not performed within a month from the previous operation or during the same hospitalization for the same disease and reviewed retrospectively. According to the surgical approach, we divided patients into two groups: median sternotomy group (S-group, n = 146), and thoracotomy group (T-group, n = 62).

RESULTS

There were no differences in sex or mean interval from the first surgery to re-operation between the two groups. Mean cardiopulmonary bypass, adhesion dissection time, bleeding control time, and operation time were significantly shorter in the T-group. The need for transfusion (p = 0.001) during adhesion dissection and the chest tube drainage (p < 0.001) were significantly lower in the T-group. There were 10 operative deaths in the S-group (6.8%) and 5 in the T-group (8.1%) (p = 0.757). Pneumonia was the most common cause of death in both groups. Post-operative bleeding did not result in death and there were no cases of wound infection in the T-group.

CONCLUSIONS

Two approaches for repeated cardiac surgery were safe and effective in terms of mortality, wound infection, bleeding, operation time, adhesion dissecting time, and bleeding control time. We were able to obtain a good visual field and perform safe surgery by applying the thoracotomy method in selective patients for cardiovascular re-operation.

Minimally invasive surgery for valvular heart disease

OPINION STATEMENT

Valvular heart disease imposes varying degrees of stress on the myocardium, which, untreated, leads to eventual ventricular dysfunction. The pathophysiologic mechanisms by which these lesions act depend not only on the affected valve, but also the degree to which they causes stenosis, regurgitation, or both. The goal of patient treatment is to identify and correct the defect before irreversible ventricular changes have occurred. Historically, the conventional surgical approach for valvular disease was via median sternotomy. Minimally invasive valve surgery (MIVS) refers to alternative surgical techniques, which avoid the trans-sternal approach. The objective is to (1) minimize surgical trauma, (2) reduce blood utilization, and (3) hasten postoperative convalesce. These goals are accomplished through the use of partial sternal, para-sternal, or thoracotomy incisions and can be adapted to robotic technologies. As with all evolving surgical techniques, the therapeutic aim of valve repair or replacement must be performed at or above the same standard of conventional surgery. Outcomes must not be sacrificed for the sake of better cosmesis. In addition, percutaneous catheter-based valvular interventions have seen rapid advances. These emerging technologies have dramatically broadened the therapeutic options, especially for an ever-increasing group of high-risk patients. As expected with all minimally invasive techniques, the major differences in the hard outcomes of mortality and major morbidity are seen in these highest risk groups. However, intermediate and low risk patients receive a tremendous benefit with regard to shortened hospital stay and quicker functional recovery. With the myriad of interventional options now available, the clinical challenge now is how best to individualize the treatment approach to a given patient providing the most durable result in order to alleviate symptoms and preserve myocardial function.

Redo mitral valve operation via right minithoracotomy--"no touch" technique

Five patients who had had previous cardiac operations underwent minimally invasive beating heart mitral valve operations via a right minithoracotomy between November 2006 and February 2009. The mean age was 64 ± 10 years and 4 were female. Under general anesthesia with single-lumen ventilation, cardiopulmonary bypass was established using the right femoral artery and vein. Through right minithoracotomy, the left atrium was opened without dissection of pericardial adhesion. The aorta was not cannulated or clamped, using a so-called "No Touch" technique. Four patients had mitral valve replacement and one had mitral ring annuloplasty with the heart beating. Mean cardiopulmonary bypass time was 118 ± 38 minutes. There was no early mortality or confirmed stroke. One patient who underwent mitral ring annuloplasty for ischemic mitral regurgitation died 3 months after surgery due to renal failure. At follow-up, New York Heart Association functional class had improved in 3 patients. In conclusion, in our initial series, minimally invasive beating heart redo mitral valve surgery through right minithoracotomy was safely performed with no early mortality.

The New Era of Cardiac Surgery Hybrid Therapy for Cardiovascular Disease

Surgical therapy for cardiovascular disease carries excellent long-term outcomes but it is relatively invasive. With the development of new devices and techniques, modern cardiovascular surgery is trending toward less invasive approaches, especially for patients at high risk for traditional open heart surgery. A hybrid strategy combines traditional surgical treatments performed in the operating room with treatments traditionally available only in the catheterization laboratory with the goal of offering patients the best available therapy for any set of cardiovascular diseases. Examples of hybrid procedures include hybrid coronary artery bypass grafting, hybrid valve surgery and percutaneous coronary intervention, hybrid endocardial and epicardial atrial fibrillation procedures, and hybrid coronary artery bypass grafting/carotid artery stenting. This multi-disciplinary approach requires strong collaboration between cardiac surgeons, vascular surgeons, and interventional cardiologists to obtain optimal patient outcomes.

Degenerative mitral valve regurgitation: best practice revolution

Degenerative mitral valve disease often leads to leaflet prolapse due to chordal elongation or rupture, and resulting in mitral valve regurgitation. Guideline referral for surgical intervention centres primarily on symptoms and ventricular dysfunction. The recommended treatment for degenerative mitral valve disease is mitral valve reconstruction, as opposed to valve replacement with a bioprosthetic or mechanical valve, because valve repair is associated with improved event free survival. Recent studies have documented a significant number of patients are not referred in a timely fashion according to established guidelines, and when they are subjected to surgery, an alarming number of patients continue to undergo mitral valve replacement. The debate around appropriate timing of intervention for asymptomatic severe mitral valve regurgitation has put additional emphasis on targeted surgeon referral and the need to ensure a very high rate of mitral valve repair, particularly in the non-elderly population. Current clinical practice remains suboptimal for many patients, and this review explores the need for a ‘best practice revolution’ in the field of degenerative mitral valve regurgitation.

Recurrent atrial myxoma: resection for Carney complex through a minimally invasive approach

Carney's complex is an autosomal dominant syndrome characterized by recurrent atrial myxomas with concurrent endocrinopathies and characteristic dermatologic features. We present the case of a woman who presented with a recurrent atrial myxoma after two previous resections for myxomas through median sternotomies. As a consequence, we utilized a minimally invasive right thoracotomy approach. We discuss the clinical and pathologic features of Carney complex and the importance of identifying individuals and families with this condition for treatment and counseling.