Right Minithoracotomy Versus Median Sternotomy for Mitral Valve Surgery: A Propensity Matched Study

Minimally invasive cardiac surgeries in 2021: annual report by Japanese society of minimally invasive cardiac surgery

PURPOSE

Although minimally invasive cardiac surgery (MICS) procedures are widely performed throughout Japan, nationwide data regarding treated cases are limited. Up-to-date results for cardiovascular surgery are vital for quality control in clinical practice. Presented here is the 2021 annual report based on data from the Japan Cardiovascular Surgery Database (JCVSD).

METHODS

Records noted in the JCVSD of patients who underwent mitral valve surgery, aortic valve replacement (AVR), coronary artery bypass grafting (CABG), atrial septum defect (ASD) closure, or cardiac tumor resection via right or left minithoracotomy, as well as thoracoscopic- or port-assisted, or robotic-assisted approaches, in 2021 were examined. Perioperative parameters including mortality and morbidity was evaluated.

RESULTS

The 30-day and in-hospital mortalities for isolated mitral valve repair (n = 1211) were 0.1% and 0.2%, respectively, while those for all mitral valve repair (n = 2017) were 0.05% and 0.2%, respectively. More than 100 facilities were found to perform fewer than five MICS mitral valve surgery cases per year. As for MICS-AVR, 30-day and in-hospital mortalities for isolated AVR (n = 818) were 0.5% and 0.5%, respectively, while those for all AVR (n = 987) were 0.6% and 1.1%, respectively. Additionally, those for MICS-CABG (n = 400) were 0.8% and 0.5%, respectively. Those for ASD (n = 183) and cardiac tumor (n = 96), were 0.5% and 0.5%, respectively, and 0% and 1.0%, respectively.

CONCLUSION

This is the first report of MICS results of procedures performed in Japan based on the 2021 JCVSD data. Additional results obtained with a similar data collection method are expected and details on MICS are being collected starting 2024.

A review and meta-analysis of conventional sternotomy versus minimally invasive mitral valve surgery for degenerative mitral valve disease focused on the last decade of evidence

OBJECTIVES

Early meta-analyses comparing minimally invasive mitral valve surgery (MIMVS) with conventional sternotomy (CS) have determined the safety of MIMVS. We performed this review and meta-analysis based on studies from 2014 onwards to examine the differences in outcomes between MIMVS and CS. Specifically, some outcomes of interest included renal failure, new onset atrial fibrillation, mortality, stroke, reoperation for bleeding, blood transfusion and pulmonary infection.

METHODS

A systematic search was performed in six databases for studies comparing MIMVS with CS. Although the initial search identified 821 papers in total, nine studies were suitable for the final analysis. All studies included compared CS with MIMVS. The Mantel - Haenszel statistical method was chosen due the use of inverse variance and random effects. A meta-analysis was performed on the data.

RESULTS

MIMVS had significantly lower odds of renal failure (OR: 0.52; 95% CI 0.37 to 0.73, p < 0.001), new onset atrial fibrillation (OR: 0.78; 95% CI 0.67 to 0.90, p < 0.001), reduced prolonged intubation (OR: 0.50; 95% CI 0.29 to 0.87, p = 0.01) and reduced mortality (OR: 0.58; 95% CI 0.38 to 0.87, p < 0.01). MIMVS had shorter ICU stay (WMD: -0.42; 95% CI -0.59 to -0.24, p < 0.001) and shorter time to discharge (WMD: -2.79; 95% CI -3.86 to -1.71, p < 0.001).

CONCLUSION

In the modern era, MIMVS for degenerative disease is associated with improved short-term outcomes when compared to the CS.

New-onset postoperative atrial fibrillation after mitral valve surgery: Determinants and the effect on survival

Objective

Mitral valve surgery (MVS) carries substantial risk of postoperative atrial fibrillation (PAF). Identifying patients who benefit from prophylactic left atrial appendage amputation (LAAA) or maze is ill-defined. To guide such interventions, we determined preoperative predictors of PAF and investigated 3-year survival of patients with PAF.

Methods

We performed a retrospective analysis of patients undergoing isolated MVS (N = 670) between 2011 and 2021. Patients with preoperative atrial fibrillation, LAAA or pulmonary vein isolation were excluded. Patient characteristics were compared between those without PAF and those who developed transient or prolonged PAF. Predictors of any PAF and prolonged PAF were identified using multivariable regression analysis.

Results

In total, 504 patients without preoperative atrial fibrillation underwent isolated MVS. Of them, 303 patients (60.2%) developed PAF; 138 (27.3%) developed transient and 165 (32.7%) developed prolonged (beyond 30 days) PAF. Patients with PAF were older (65.7 vs 54.3 years, P < .001), with larger left atria (4.8 vs 4.3 cm, P < .001), greater prevalence of hypertension (60% vs 47.8%, P < .05), and were New York Heart Association class III/IV (36% vs 8.5%, P < .001). Independent predictors of PAF included left atria volume index (odds ratio [OR], 1.02; P < .003), older age (OR, 1.04; P < .001), heart failure (OR, 6.73; P < .001), and sternotomy (OR, 2.19; P < .002). Age, heart failure, and sternotomy were independent predictors of prolonged PAF. Patients with PAF had greater mortality at 3 years compared with those without PAF (5.3% vs 0.5%, P < .005). On multivariable analysis, PAF was associated with increased mortality (hazard ratio, 7.81; P < .046).

Conclusions

PAF is common after MVS and associated with late mortality. Older age, advanced heart failure, and sternotomy are associated with prolonged PAF. These factors may identify patients who would benefit from prophylactic LAAA or ablation during MVS.

Outcomes and residual gap analysis after the modified cryomaze procedure performed via right minithoracotomy versus sternotomy

Objectives

Developments in both technique and technology have enabled surgeons to perform the maze procedure via right minithoracotomy (RMT) to treat atrial fibrillation (AF). This study aimed to clarify the outcomes of the modified cryomaze procedure via the RMT approach compared with the sternotomy approach.

Methods

The study cohort comprised 803 consecutive patients who underwent a modified cryomaze procedure (130 via RMT and 673 via sternotomy) for paroxysmal AF and persistent AF from January 2001 to March 2022. The Gray test was applied to compare the incidence of recurrent atrial tachyarrhythmias. Additionally, residual electrical gaps were investigated in the patients who underwent additional catheter ablation for recurrent atrial tachyarrhythmias.

Results

The respective 1-, 2-, and 3-year cumulative incidences of recurrent atrial tachyarrhythmias were 13.1%, 19.5%, and 23.1% in the RMT group, and 9.3%, 10.9%, and 12.8% in the sternotomy group (Gray test P = .036). All 31 patients with recurrent atrial tachyarrhythmias underwent additional catheter ablation, comprising 14 (10.8%) in the RMT group and 17 (2.5%) in the sternotomy group. There was a significant intergroup difference in the site of residual electrical gaps; the RMT group more frequently had residual gaps in the tricuspid annulus than the sternotomy group (6.2% vs 0.4%; P < .001).

Conclusions

In the modified cryomaze procedure via the RMT approach, ablation failure is more likely to occur at the tricuspid annulus, where the surgical field of view is relatively poor compared with the sternotomy approach. Therefore, surgical ablation should be performed with caution when the RMT approach is used.

Minimally invasive mitral valve reconstruction: Is it an "all-comers" procedure?

BACKGROUND AND AIM OF THE STUDY

The debate on the usefulness of the minimally invasive approach in mitral valve surgery is still open. The aim of this study is to describe a single-center case series of all comers undergoing minimally invasive mitral valve reconstruction.

METHODS

From 2010 to 2019, all the data recorded in the medical records of 893 consecutive patients undergoing mitral valve reconstruction through a right mini-thoracotomy were retrospectively collected. All patients were contacted by telephone for remote evaluation and integration of echocardiographic information on surgical results.

RESULTS

Mean age was 62.2 ± 14.5; 447 (50%) were female and mean log EuroSCORE was 2.5 ± 2.8%. At a mean follow-up of 4.1 ± 2.2 years (median 3.9), a total of 24 deaths (2.68%) were recorded. Twenty-four patients required rehospitalization for cardiac causes, 13 (1.4%) patients had at least moderate mitral insufficiency on follow-up echocardiography and, of these, seven patients underwent reoperation (0.8%). The cumulative hazard showed that 8.3% of patients experienced at least one event at 5 years. NYHA class improved significantly with 874 patients in NYHA class I, 13 in NYHA class II, 6 in NYHA class III, and 0 in NYHA class IV at last follow-up (p < .001 from baseline as reference point).

CONCLUSIONS

In a high-volume center, mitral valve surgery using a minimally invasive approach is a feasible treatment option for all-comers and is associated with excellent results that are maintained at clinical and echocardiographic follow-up.

Conventional sternotomy versus right mini-thoracotomy versus robotic approach for mitral valve replacement/repair; insights from a network meta-analysis

OBJECTIVE

Minimally invasive cardiac surgery (MICS) through right mini-thoracotomy as well as robotic surgery has emerged for the last decade for mitral valve surgery. However, their risks and benefits are not fully understood yet. Thus, we conducted a network meta-analysis comparing the early- and long-term outcomes of mitral valve surgery via the conventional sternotomy, MICS, and robotic approaches.

EVIDENCE ACQUISITION

MEDLINE and EMBASE were searched through November, 2020 to identify randomized controlled trials (RCTs) and propensity-score matched (PSM) trials that investigated early- and long-term outcomes after mitral surgery via the conventional sternotomy, MICS, and robotic approaches. A subalalysis focusing on only subjects who initially underwent mitral valve repair was also conducted.

EVIDENCE SYNTHESIS

Our systematic literature search identified 2 RCTs and 19 PSM studies. MICS was related to significant risk reductions of permanent pacemaker implantation, surgical site infection, and transfusion compared to the sternotomy approach. The robotic approach was associated with a significant increase in re-exploration for bleeding compared to sternotomy. The subanalysis showed that MICS was associated with a significant increase requiring mitral valve reoperation compared to the sternotomy approach (hazard ratio [95% confidence interval] =7.33 [1.54-34.97], p=0.012), while no significant difference was observed between the sternotomy and the robotic approach.

CONCLUSIONS

Our network meta-analysis demonstrated that MICS was associated with better short-term outcomes compared to the sternotomy approach. Mitral valve reoperation was more frequent with MICS compared with the sternotomy approach after mitral valve repair, while no difference was observed between the sternotomy and robotic approaches.

Right Ventricular Function After Minimally Invasive Mitral Valve Surgery

OBJECTIVES

Right ventricular (RV) dysfunction is a significant cause of morbidity and mortality after cardiac surgery. Minimally invasive mitral valve surgery (MIMVS) increasingly is being performed. The authors aim was to evaluate postoperative RV function in patients who underwent MIMVS versus traditional mitral valve surgery.

DESIGN

Six hundred seventy-five patients who underwent elective isolated mitral valve surgery at Centro Cardiologico Monzino from January 2016 to December 2019 were analyzed. After 1:1 propensity score matching, 60 patients were identified in the MIMVS (study group A) and 58 patients in the median sternotomy (control group B) and compared.

SETTING

A university-affiliated scientific institute, monocentric.

PARTICIPANTS

Patients.

INTERVENTIONS

Mitral valve surgery.

MEASUREMENTS AND MAIN RESULTS

No in-hospital deaths occurred. Aortic cross-clamp time (102 [87.5-119] v 83 [61-109] minutes, p = 0.0001), cardiopulmonary bypass duration (161.5 [142.5-181] v 105.5 [74-134] minutes, p < 0.0001) and intensive care unit stay (47 [44-72] v 45 [40-47] hours, p = 0.0015) were significantly longer in group A. The tricuspid annular plane systolic excursion was not different between group A and group B neither postoperatively (15 ± 3 v 14 ± 4 mm, p = 0.1) nor at three-month follow-up (18 ± 4 v 15 ± 3 mm, p = 0.3). No differences in peak postoperative lactates, inotropic score, central venous pressure, and pulmonary artery pulsatility index were observed. The length of hospital stay was significantly shorter in the minimally invasive group (ten [eight-13] v 12 [ten-17], p = 0.006).

CONCLUSION

The authors study showed that the surgical strategy had no significant impact on postoperative RV function after mitral valve surgery.

Minimally Invasive and Robotic Mitral Valve Surgery: Methods and Outcomes in a 20-Year Review

In the mid- to late-1990s the cardiac surgery community began to apply limited incisions in mitral valve surgery. Ministernotomies and right-sided minithoracotomies were placed instead of the classic midline sternotomy. Adjunct technology such as videoscopy, advanced peripheral cannulation techniques, procedure specific long shafted surgical instruments, as well as surgical robots became available, and the procedures were refined in a stepwise fashion. In 2021, minimally invasive mitral valve repair is routine at many centers around the globe. We reviewed a total of 50 consecutive patient series published on the topic between 1999 and 2019. Three main versions of minimally invasive mitral valve surgery were applied in 20,539 patients. The surgical methods, their specific results, and the cumulative outcome of less invasive mitral valve surgery published over more than 20 years are reported and an integrated view on what less invasive mitral valve surgery can offer is presented.

Minimally invasive tricuspid valve surgery without caval occlusion: Short and midterm results

OBJECTIVE

The use of minimally invasive or transcatheter interventions rather than standard full sternotomy operations to treat tricuspid valve (TV) disease is increasing. The debate however is still open regarding venous drainage management during cardiopulmonary bypass (CPB) and wheatear or not superior and inferior vena cava should be occluded during the opening of the right atrium to avoid air entrance in the venous line. The aim of the present study is to report operative outcomes and midterm follow-up results of minimally invasive TV surgery performed without caval occlusion.

METHODS

A retrospective outcome evaluation from institutional records was performed with prospective data entry. Considered were consecutive patients who underwent right mini-thoracotomy TV surgery isolated or combined with mitral valve surgery during the period from June 2013 to February 2020. A telephone and echocardiographic follow-up was performed.

RESULTS

During the study period, 68 consecutive patients underwent minimally invasive TV surgery without occlusion of cava veins. The mean age was 69 ± 14 years and 48 (70%) were female. All operations were performed safely without air-lock during CPB. A perioperative cerebral stroke occurred in one patient. The survival at a 5- and 8-year follow-up was 100% and 79%, respectively. No severe tricuspid regurgitation was evident at echocardiographic follow-up.

CONCLUSION

Our results show that performing tricuspid surgery without caval occlusion is safe. The air was captured by the active vacuum drainage system without causing damage. Midterm follow-up data confirm that a minimally invasive approach does not alter the quality of surgery.

Does minimal invasive cardiac surgery reduce the incidence of post-operative atrial fibrillation?

Atrial fibrillation (AF) is the most common post-operative complication and tends to be the most common arrhythmia after cardiac surgery. The etiology and risk factors for post-operative AF are poorly understood, but older age, large left atrium, diffuse coronary artery disease, a history of AF paroxysms and in general, pre-existing cardiac conditions that cause restricting and susceptibility towards inflammation have been consistently linked with post-operative atrial fibrillation (POAF). It has been traditionally thought that post-operative AF is transient, well-tolerated, benign to the patient and self-limiting complication of cardiac surgery that was temporary and easily treated. However, recent evidence suggests that POAF may be more "malignant" than previously thought, associated with follow-up mortality and morbidity. Several minimally invasive approaches, including the right parasternal approach, upper and lower mini-sternotomy (MS), V-shaped, Z-shaped, inverse-T, J-, reverse-C and reverse-L partial MS, transverse sternotomy and right mini-thoracotomy, have been developed for cardiac surgery operations since 1993 and have been associated with better outcomes and lower perioperative morbidity compared to full sternotomy (FS). The common goal of several minimally invasive approaches is to reduce invasiveness and surgical trauma. According to a statement from the American Heart Association (AHA), the term "minimally invasive" refers to a small chest wall incision that does not include a FS. This review is aimed to evaluate the use of minimally invasive techniques like mini-sternotomy, mini-thoracotomy and hybrid techniques versus conventional techniques which are used in cardiac surgery and to compare the frequency of post-operative AF and its effect on post-operative complications, morbidity and mortality, after cardiac surgery operations with FS versus cardiac surgery operations with the use of minimally invasive techniques.

The Opportunities and Limitations of Minimally Invasive Cardiac Surgery

BACKGROUND

Over the past two decades, minimally invasive techniques for classic heart valve surgery and isolated bypass surgery have been developed that enable access to the heart via partial sternotomy for most aortic valve procedures and via sternotomy-free mini-thoracotomy for other procedures.

METHODS

We review the current evidence on minimally invasive cardiac surgery on the basis of pertinent randomized studies and database studies retrieved by a selective search in the MEDLINE and PubMed Central databases, as well as by the Google Scholar search engine.

RESULTS

A PubMed search employing the search term "minimally invasive cardiac surgery" yielded nearly 10 000 hits, among which there were 7 prospective, randomized, controlled trials (RCTs) on aortic valve replacement, with a total of 477 patients, and 3 RCTs on mitral valve surgery, with a total of 340 patients. Only limited reports of specified centers are currently available for multiple valvular procedures and multiple coronary artery bypass procedures. The RCTs reveal that the minimally invasive techniques are associated with fewer wound infections and faster mobilization, without any difference in survival. Minimally invasive procedures are technically demanding and have certain anatomical prerequisites, such as appropriate coronary morphology for multiple bypass operations and the position of the aorta in the chest for sternotomy-free aortic valve procedures. The articles reviewed here were presumably affected by selection bias, in that patients in the published studies were preselected, and there may have been negative studies that were not published at all.

CONCLUSION

Specialized surgeons and centers can now carry out many cardiac valvular and bypass operations via minithoracotomy rather than sternotomy. According to current evidence, these minimally invasive techniques yield results that are at least as good as classic open-heart surgery.

Right minithoracotomy versus conventional median sternotomy for patients undergoing mitral valve surgery and Cox-maze IV ablation with entirely bipolar radiofrequency clamp

Cox-maze IV ablation by bipolar radiofrequency clamp was considered to be only performed through median sternotomy (MS), but impossible through right minithoracotomy (RM). Now, we developed a novel technique of performing Cox-maze IV ablation entirely by bipolar clamp through RM. To compare the outcomes of RM or MS for patients undergoing mitral valve surgery and concomitant Cox-maze IV ablation with entirely bipolar clamp. All 152 patients underwent mitral valve surgery and concomitant Cox-maze IV ablation with bipolar clamp through RM (n = 69) or MS (n = 83) were analyzed for outcome differences. The etiology of mitral valve disease was rheumatic (n = 97) and degenerative (n = 55). All patients had long-standing persistent atrial fibrillation (AF). Diameter of left atrium ranged from 42 to 60 mm. All patients successfully underwent Cox-maze IV ablation by bipolar clamp. RM group had longer cardiopulmonary bypass time (130.3 ± 17.7 vs 115.3 ± 14.4 min; P < 0.001) and aortic cross-clamp time (91.8 ± 12.7 vs 74.6 ± 9.3 min; P < 0.001). But mechanical ventilation time (14.2 ± 6.6 vs 21.3 ± 9.0 h; P < 0.001) and hospital length of stay (9.3 ± 2.6 vs 11.7 ± 3.0 days; P < 0.001) were shorter in RM group. At discharge, the maintenance of normal sinus rhythm (NSR) was 94.2% in RM group and 95.1% in MS group (P = 1.000). Cumulative maintenance of NSR at 2 years postoperatively was 85.1 ± 5.8% in RM group and 88.6 ± 3.6% in MS group (P = 0.767). RM can achieve similar therapeutic effect to MS for patients undergoing mitral valve surgery and concomitant Cox-maze IV ablation with entirely bipolar clamp. In addition, patients through RM had faster recovery.

Minimal access mitral valve repair in a patient with a right pneumonectomy for Scimitar syndrome

A 61-year old man known with chronic atrial fibrillation was referred to our unit via the multidisciplinary team meeting, with severe mitral regurgitation secondary to prolapse of anterior mitral leaflet. In 1968, he had undergone right pneumonectomy due to Scimitar syndrome. Dense adhesions due to previous interventions, such as thoracotomy, make it difficult to insert ports, and this is therefore considered a relative contraindication to port access approach to the mitral valve. The anatomical position of the heart in the mediastinum was completely distorted due to the shift of the mediastinum to the right following previous surgery. Our report illustrates the operative success that can be achieved in such complex situations. Computed tomography scanning and on table transoesophageal and transthoracic echocardiography were the tools used in conjunction to achieve the best possible approach. This case promotes the use of minimal access approach in the experienced hands so that such complex procedures can be carried out without any complication and yield good results.