Techniques and results of direct-access minimally invasive mitral valve surgery: a paradigm for the future

Minimally invasive vs. conventional mitral valve surgery: a meta-analysis of randomised controlled trials

Objective

The evidence underlying the efficacy and safety of minimally invasive mitral valve surgery (MIMVS) is inconclusive. We conducted a meta-analysis to evaluate whether MIMVS improves clinical outcomes compared with conventional sternotomy.

Methods

We searched MEDLINE (via PubMed), Embase, the Cochrane Library, and ClinicalTrials.gov from inception to January 2024 for all randomised controlled trials (RCTs), comparing MIMVS with conventional mitral valve surgery. RevMan 5.4 was used to analyse the data with risk ratio (RR) and mean difference (MD) as the effect measures.

Results

Eight studies reporting data on 7 RCTs were included in our review. There was no significant difference in all-cause mortality, the number of patients requiring blood product transfusion, and the change from baseline in the SF-36 physical function scores between the MIMVS and conventional sternotomy groups. MIMVS reduced the length of hospital stay (MD -2.02 days, 95% CI: -3.66, -0.39) but did not affect the length of ICU stay, re-operation for bleeding, and the incidence of renal injury, wound infection, neurological events, and postoperative moderate or severe mitral regurgitation. MIMVS was associated with a trend toward lower postoperative pain scores (MD -1.06; 95% CI: -3.96 to 0.75).

Conclusions

MIMVS reduced the number of days spent in the hospital and showed a trend toward lower postoperative pain scores, but it did not decrease the risk of all-cause mortality or the number of patients needing blood product transfusions. Further large-scale RCTs are required to inform definitive conclusions, particularly with regard to quality-of-life outcomes investigating functional recovery.

Systematic Review Registration

PROSPERO (CRD42023482122).

A Retrospective Evaluation of Endo-Aortic Balloon Occlusion Compared to External Clamping in Minimally Invasive Mitral Valve Surgery

We compare outcomes of endo-aortic balloon occlusion (EABO) vs external aortic clamping (EAC) in patients undergoing minimally invasive mitral valve surgery (MIMVS) in the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database. Adults undergoing mitral valve surgery (July 2017-December 2018) were identified within the STS database (N = 60,607). Total 7,978 patients underwent a minimally invasive approach (including robotically assisted). About 1,163 EABO patients were 1:1 propensity-matched to EAC patients using exact matching on age, sex, and type of mitral procedure, and propensity score average matching for 16 other risk indicators. Early outcomes were compared. Categorical variables were compared using logistic regression; hospital and intensive care unit length of stay were compared using negative binomial regression. In the matched cohort, mean age was 62 years; 35.9% were female, and 86% underwent mitral valve repair. Cardiopulmonary bypass time was shorter for EABO vs EAC group (125.0 ± 53.0 vs 134.0 ± 67.0 minutes, P = 0.0009). There was one aortic dissection in the EAC group and none in the EABO group (P value > 0.31), and no statistically significant differences in cross-clamp time, major intraoperative bleeding, perioperative mortality, stroke, new onset of atrial fibrillation, postoperative acute kidney injury, success of repair. Median hospital LOS was shorter for EABO vs EAC procedures (4 vs 5 days, P < 0.0001). In this large, retrospective, STS database propensity-matched analysis ofpatients undergoing MIMVS, we observed similar safety outcomes for EABO and EAC, including no aortic dissections in the EABO group. The EABO group showed slightly shorter CPB times and hospital LOS.

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".

Successful surgical treatment approach for mitral valve vegetation of infective endocarditis after severe soft tissue infection with mediastinitis

Transesophageal echocardiography is mandatory if you do suspect infective endocarditis. By approaching via a small right thoracotomy, vegetectomy and mitral valvuloplasty following severe mediastinitis were successfully accomplished without any complications.

Clinical outcomes associated with retrograde arterial perfusion in minimally invasive mitral valve surgery: a systematic review

INTRODUCTION

Given several reports of an increased neurologic risk with retrograde arterial perfusion in minimally invasive mitral valve surgery, we sought to identify and synthesize the best available evidence on the influence of perfusion strategy on post-operative clinical outcomes in this population.

METHODS

A systematic search of PubMed, EMBASE, MEDLINE, and Cochrane library databases was performed to identify publications comparing clinical outcomes associated with antegrade and retrograde arterial perfusion in minimally invasive mitral valve surgery. Pre-specified outcomes of interest were neurologic events, mortality, and renal failure. The search was performed by two independent reviewers, with data abstraction following.

RESULTS

Seven observational studies were included in this review, with a total patient population of 5,385. Six were retrospective cohort in design, with a single small prospective cohort study identified. When available, adjusted publication-specific risk estimates were abstracted and included preferentially over unadjusted or reviewer-derived risk estimates. Meta-analysis was felt to be heavily flawed in the context of few small studies identified and was not performed. In adjusted estimates, there appeared to be an increased risk of neurologic complications with retrograde arterial perfusion. There was a null pattern apparent between arterial perfusion strategy and each of 30-day mortality and renal failure.

CONCLUSION

Retrograde arterial perfusion in minimally invasive mitral valve surgery may be associated with an increased risk of neurologic events, without affecting the risk of 30-day mortality or renal failure. Although these patterns were identified, an overall paucity of evidence justifies further study.

Intermediate-Term Results of 505 Consecutive Minithoracotomy Mitral Valve Procedures

Background

Patient demand for less invasive surgery and interest in avoiding sternotomy has led to the increased use of the minithoracotomy for mitral valve surgery. Although the feasibility of this approach has been established, few data are available regarding intermediate-term results.

Methods

A total of 505 consecutive minithoracotomy mitral valve procedures performed between 1996 and 2004 were analyzed. Procedures were mitral replacement (191/505, 38%) and repair (314/505, 62%). Concomitant cardiac procedures were performed in 78 cases (13%) (maze 36, tricuspid 29, atrial septal defect/patent foramen ovale 13) and reoperation in 92 cases (18%). Arterial cannulation was ascending aorta in 403 cases (80%), femoral in 101 cases (20%), and axillary in 1 case (< 1%). An endoluminal aortic clamp was used in 406 cases (80%), an external clamp was used in 19 cases (4%), and 80 procedures (16%) were performed with ventricular fibrillation. Robotic assistance was used in 12 cases (2%).

Results

Mean patient age was 58.7 years (range 18–90 years). Median follow-up was 3.1 years. Operative mortality was 4 of 505 cases (<1%). Major complications included stroke in 7 cases (1%) and reoperation for bleeding in 18 cases (4%); there were no cases of mediastinitis. Late complications included chronic aortic dissection in 1 case (<1%) and mitral reoperation in 13 cases (3%) (subacute bacterial endocarditis 6, failed repair 2, other 5). Five-year survival was (83% ± 2%) and freedom from mitral reoperation was (96% ± 1%). Follow-up echocardiograms were available in 246 of 314 cases (78%) mitral repairs and mean mitral regurgitation grade was 1 ± 1. Mitral regurgitation was grade 3–4+ in 14 of 246 cases (6%) (subacute bacterial endocarditis 4, low ejection fraction 5, other 5). Five-year freedom from 3–4+ mitral regurgitation was 89% ± 3%.

Conclusions

Mitral valve surgery via minithoracotomy can be performed safely with a low perioperative complication rate. A durable technical result and excellent long-term survival can be expected.

Navigation of guidewires and catheters in the body during intervention procedures: a review of computer-based models

Guidewires and catheters are used during minimally invasive interventional procedures to traverse in vascular system and access the desired position. Computer models are increasingly being used to predict the behavior of these instruments. This information can be used to choose the right instrument for each case and increase the success rate of the procedure. Moreover, a designer can test the performance of instruments before the manufacturing phase. A precise model of the instrument is also useful for a training simulator. Therefore, to identify the strengths and weaknesses of different approaches used to model guidewires and catheters, a literature review of the existing techniques has been performed. The literature search was carried out in Google Scholar and Web of Science and limited to English for the period 1960 to 2017. For a computer model to be used in practice, it should be sufficiently realistic and, for some applications, real time. Therefore, we compared different modeling techniques with regard to these requirements, and the purposes of these models are reviewed. Important factors that influence the interaction between the instruments and the vascular wall are discussed. Finally, different ways used to evaluate and validate the models are described. We classified the developed models based on their formulation into finite-element method (FEM), mass-spring model (MSM), and rigid multibody links. Despite its numerical stability, FEM requires a very high computational effort. On the other hand, MSM is faster but there is a risk of numerical instability. The rigid multibody links method has a simple structure and is easy to implement. However, as the length of the instrument is increased, the model becomes slower. For the level of realism of the simulation, friction and collision were incorporated as the most influential forces applied to the instrument during the propagation within a vascular system. To evaluate the accuracy, most of the studies compared the simulation results with the outcome of physical experiments on a variety of phantom models, and only a limited number of studies have done face validity. Although a subset of the validated models is considered to be sufficiently accurate for the specific task for which they were developed and, therefore, are already being used in practice, these models are still under an ongoing development for improvement. Realism and computation time are two important requirements in catheter and guidewire modeling; however, the reviewed studies made a trade-off depending on the purpose of their model. Moreover, due to the complexity of the interaction with the vascular system, some assumptions have been made regarding the properties of both instruments and vascular system. Some validation studies have been reported but without a consistent experimental methodology.

Recent Developments in Minimally Invasive Cardiac Surgery: Evolution or Revolution?

Intraluminal aortic clamping has been achieved until now by means of a sophisticated device consisting of a three-lumen catheter named Endoclamp, which allows at the same time occlusion of the aorta, antegrade delivering of cardioplegia, and venting through the aortic root. This tool has shown important advantages allowing aortic occlusion and perfusate delivering without a direct contact with ascending aorta reducing meanwhile the risk of traumatic and/or iatrogenic injuries. Recently, a new device (Intraclude catheter) with the same characteristics and properties has been proposed and introduced in clinical practice. The aim of this paper is to investigate the differences between Endoclamp and Intraclude catheters and to analyze the advantages advocated by this new device for intraluminal aortic occlusion since it is noticeable as these new technological tools are gaining more and more attractiveness due to their appraised clinical efficacy.

Minimally invasive mitral surgery through right mini-thoracotomy under direct vision

In the 1990s, the success of 'minimally invasive' laparoscopic operations in other surgical subspecialties sparked an interest in minimally-invasive approaches for cardiac surgery, specifically for mitral valve repair. In 1996 at New York University (NYU) we began our experience with minimally invasive mitral valve repair performed through a small right anterior mini-thoracotomy incision using the Port-Access system in a phase I clinical trial. This was the beginning of our extensive right mini-thoracotomy experience for mitral valve repair at NYU. Currently at our institution the preferred approach for the right mini-thoracotomy mitral valve surgery is through the 3rd or 4th interspace mini-thoracotomy incision. Perfusion is accomplished with direct aortic or femoral cannulation, long femoral venous cannula drainage, and a retrograde cardioplegia catheter placed trans-atrialy in the coronary sinus under TEE guidance. An antegrade cardioplegia and venting needle is placed in the ascending aorta and direct external aortic clamping is achieved with one of several specialized crossclamps. With over four decades of experience, more than 4,000 patients have undergone mitral valve repair at NYU including 1,922 performed through a right mini-thoracotomy. We have reported an overall operative mortality of 1.3%, 8-year freedom from reoperation of 95%, freedom from reoperation or severe recurrent mitral regurgitation of 93%, and freedom from all valve-related complications of 90% for our initial series of 1,071 right mini-thoracotomy mitral valve repair. Based on our extensive experience we believe that mitral valve repair through a right mini-thoracotomy provides a durable and safe alternative to a traditional sternotomy with the benefits of improved cosmesis, reduced post-operative pain, less blood loss with fewer blood transfusions, fewer infections, shorter length of stay, and faster return to activity. It is our standard of care approach for mitral valve surgery.

Minimally Invasive versus Conventional Open Mitral Valve Surgery a Meta-Analysis and Systematic Review

Objective

This meta-analysis sought to determine whether minimally invasive mitral valve surgery (mini-MVS) improves clinical outcomes and resource utilization compared with conventional open mitral valve surgery (conv-MVS) in patients undergoing mitral valve repair or replacement.

Methods

A comprehensive search of MEDLINE, Cochrane Library, EMBASE, CTSnet, and databases of abstracts was undertaken to identify all randomized and nonrandomized studies up to March 2010 of mini-MVS through thoracotomy versus conv-MVS through median sternotomy for mitral valve repair or replacement. Outcomes of interest included death, stroke, myocardial infarction, aortic dissection, need for reintervention, and any other reported clinically relevant outcomes or indicator of resource utilization. Relative risk and weighted mean differences and their 95% confidence intervals were analyzed as appropriate using the random effects model. Heterogeneity was measured using the I2 statistic.

Results

Thirty-five studies met the inclusion criteria (two randomized controlled trials and 33 nonrandomized studies). The mortality rate after mini-MVS versus conv-MVS was similar at 30 days (1.2% vs 1.5%), 1 year (0.9% vs 1.3%), 3 years (0.5% vs 0.5%), and 9 years (0% vs 3.7%). A number of clinical outcomes were significantly improved with mini-MVS versus conv-MVS including atrial fibrillation (18% vs 22%), chest tube drainage (578 vs 871 mL), transfusions, sternal infection (0.04% vs 0.27%), time to return to normal activity, and patient scar satisfaction. However, the 30-day risk of stroke (2.1% vs 1.2%), aortic dissection/injury (0.2% vs 0%), groin infection (2% vs 0%), and phrenic nerve palsy (3% vs 0%) were significantly increased for mini-MVS versus conv-MVS. Other clinical outcomes were similar between groups. Cross-clamp time, cardiopulmonary bypass time, and procedure time were significantly increased with mini-MVS; however, ventilation time and length of stay in intensive care unit and hospital were reduced.

Conclusions

Current evidence suggests that mini-MVS maybe associated with decreased bleeding, blood product transfusion, atrial fibrillation, sternal wound infection, scar dissatisfaction, ventilation time, intensive care unit stay, hospital length of stay, and reduced time to return to normal activity, without detected adverse impact on long-term need for valvular reintervention and survival beyond 1 year. However, these potential benefits for mini-MVS may come with an increased risk of stroke, aortic dissection or aortic injury, phrenic nerve palsy, groin infections/complications, and increased cross-clamp, cardiopulmonary bypass, and procedure time. Available evidence is largely limited to retrospective comparisons of small cohorts comparing mini-MVS versus conv-MVS that provide only short-term outcomes. Given these limitations, randomized controlled trials with adequate power and duration of follow-up to measure clinically relevant outcomes are recommended to determine the balance of benefits and risks.

The use of a mini bypass circuit for minimally invasive mitral valve surgery

Introduction: The purpose of the study is to clinically evaluate minimally invasive mitral valve surgeries (MIMVS) using a mini bypass circuit. The challenge to perfusion is to keep pace with MIMVS, with demonstrated improvements in perfusion-related technologies.

Methods: From October 28, 2005 to September 10, 2008, we retrospectively evaluated thirty-four elective cases which used the mini-circuit (Medtronic Resting Heart System®), with respect to safety, efficacy, cannulation technique, blood usage, resultant hemoglobin, length of ICU and hospital stay, and complications.

Conclusion: The Medtronic Resting Heart System® alleviates many factors, such as high shear stress, turbulence, air to blood interface and decreased oncotic pressure caused by hemodilution, providing more efficient perfusion to our MIMVS patients. We demonstrate, with minor circuit modifications and attention to venous air issues, that this mini-circuit can be used safely and effectively, while being associated with improvements in patient outcomes.

Percutaneous and Minimally Invasive Valve Procedures

The incidence of valvular heart disease is expected to increase over the next several decades as a large proportion of the US demographic advances into the later decades of life. At the same time, the next several years can be anticipated to bring a broad transition of surgical therapy to minimally invasive (minithoracotomy and small port) access and the more gradual introduction of percutaneous approaches for the correction of valvular heart disease. Broad acceptance of these technologies will require careful and sometimes perplexing comparisons of the outcomes of these new technologies with existing standards of care. The validation of percutaneous techniques, in particular, will require the collaboration of cardiologists and cardiac surgeons in centers with excellent surgical and catheter experience and a commitment to trial participation. For the near term, percutaneous techniques will likely remain investigational and will be limited in use to patients considered to be high risk or to inoperable surgical candidates. Although current-generation devices and techniques require significant modification before widespread clinical use can be adopted, it must be expected that less invasive and even percutaneous valve therapies will likely have a major impact on the management of patients with valvular heart disease over the next several years.

Technology insight: brain MRI and cardiac surgery--detection of postoperative brain ischemia

Annually, an estimated 1 million patients undergo heart surgery worldwide. Unfortunately, stroke continues to be a frequent complication of cardiac surgery, with the specific cerebrovascular risk depending upon the particular surgical procedure performed. Neuroimaging has an integral role in the initial evaluation and management of patients who present with acute stroke symptoms following cardiac surgery. The aim of this paper is to review the role brain MRI has in detecting postoperative brain ischemia in these patients. Multimodal MRI--using diffusion-weighted MRI (DWI), perfusion-weighted MRI, and gradient-recalled echo imaging--has an excellent capacity to identify and delineate the size and location of acute ischemic strokes as well as intracerebral hemorrhages. This differentiation is critical in making appropriate treatment decisions in the acute setting, such as determining patient eligibility for thrombolytic or hemodynamic therapies. At present, DWI offers prognostic value in patients with strokes following cardiac surgery. Additionally, DWI could be a valuable tool for evaluating stroke preventive measures as well as therapeutic interventions in patients undergoing CABG surgery.

Robotic mitral valve surgery: a United States multicenter trial

OBJECTIVE

In a prospective phase II Food and Drug Administration trial, robotic mitral valve repairs were performed in 112 patients at 10 centers by using the da Vinci surgical system. The safety of performing valve repairs with computerized telemanipulation was studied.

METHODS

After institutional review board approval, informed consent was obtained. Patients had moderate to severe mitral regurgitation. Operative technique included peripheral cardiopulmonary bypass, a 4- to 5-cm right minithoracotomy, a transthoracic aortic crossclamp, and antegrade cardioplegia. The successful study end point was grade 0 or 1 mitral regurgitation by transthoracic echocardiography at 1 month after surgery.

RESULTS

Valve repairs included quadrangular resections, sliding plasties, edge-to-edge approximations, and both chordal transfers and replacements. The average age was 56.4 +/- 0.09 years (mean +/- SEM). There were 77 (68.8%) men and 35 (31.2%) women. Valve pathology was myxomatous degeneration in 105 (91.1%), and 103 (92.0%) had type II leaflet prolapse. Leaflet repair times averaged 36.7 +/- 0.2 minutes, with annuloplasty times of 39.6 +/- 0.1 minutes. Total robot, aortic crossclamp, and cardiopulmonary bypass times were 77.9 +/- 0.3 minutes, 2.1 +/- 0.1 hours, and 2.8 +/- 0.1 hours, respectively. On 1-month transthoracic echocardiography, 9 (8.0%) had grade 2 mitral regurgitation, and 6 (5.4%) of these had reoperations (5 replacements and 1 repair). There were no deaths, strokes, or device-related complications.

CONCLUSIONS

Multiple surgical teams performed robotic mitral valve repairs safely early in development of this procedure, with a reoperation rate of 5.4%. Advancements in robotic design and adjunctive technologies may help in the evolution of this minimally invasive technique by decreasing operative times.

Brachial Artery Cannulation Facilitates Lower Ministernotomy Cardiac Surgery

BACKGROUND

Lower ministernotomy has become a more popular approach for many heart operations. However, cannulation of the ascending aorta may cause serious complications. Femoral and brachial arteries have been used for alternative arterial cannulation sites.

MATERIALS AND METHODS

The lower ministernotomy approach was used in 65 patients. Ascending aortic cannulation was performed in group 1 (n = 38), femoral cannulation in group 2 (n = 12), and brachial cannulation in group 3 (n = 15) patients. Brachial artery diameter was measured preoperatively by Doppler ultrasound in the preoperative period.

RESULTS

Average cross-clamp time for femoral and brachial artery cannulated patients was significantly shorter than in patients in group 1 (31 +/- 9 and 35 +/- 6 minutes, respectively) (p = 0.034). Total cardiopulmonary bypass (CPB) time was 56 +/- 11 minutes for group 1, 39 +/- 7 minutes for group 2, and 41 +/- 5.4 minutes for group 3 (p = 0.041). Operation time was 112 +/- 24, 88 +/- 12, and 91 +/- 11 minutes for the groups 1, 2, and 3, respectively. There was also statistically significant difference between group 1 and group 3 comparisons with regard to CPB time (p = 0.041). Difficult exposure from many cannulas impedes access and lengthens the operation in group I. Superficial wound infection developed in seven patients in group 1, one patient in group 2, and one patient in group 3.

CONCLUSION

Cannulation of the brachial artery is superior to the femoral due to possible infection and lymph leakage with the latter and both are superior to central cannulation when lower ministernotomy is performed. By avoiding the difficulties of central aortic cannula placement the operative time is decreased and possible wound edge is protected as lesser exposure is required.

Endoscopic mitral valve repair: feasible, reproducible, and durable

OBJECTIVE

We sought to document the feasibility, safety, and effectiveness of performing mitral valve repair using a totally endoscopic approach.

METHODS

Between February 1997 and October 1, 2001, 187 patients underwent totally endoscopic mitral valve repair at our institution. The mean age was 60.7 +/- 13.1 years, and 62% were male. Median preoperative functional class and degree of mitral regurgitation were II and 4, respectively. Data collection included an institutional protocol assessing procedure-related pain, cosmesis, and functional recovery. Statistical analysis included Kaplan-Meier and Cox regression methods. Mean follow-up was 19 +/- 15.2 months and was 100% complete.

RESULTS

Associated atrial procedures were performed in 9.1% (n = 17) of the patients. Two patients required intraoperative conversion to sternotomy. Thoracoscopic re-evaluation for suspected bleeding (n = 19) was part of our aggressive postoperative management. One patient required sternotomy for control of bleeding. Hospital mortality included 1 (0.5%) patient and was not technology related. There were 1 early and 6 late reoperations, 4 of which were due to endocarditis. No risk factors for repair failure could be detected. Freedom from mitral valve reoperation at 4 years was 93.3% +/- 2.6%. The median degree of mitral regurgitation at follow-up was 0. Ninety-three percent of the patients were highly satisfied with either no or mild postoperative pain, and 98.4% believed they had an aesthetically pleasing scar.

CONCLUSIONS

Totally endoscopic mitral valve repair can be done safely with excellent results and a high degree of patient satisfaction. It is now our exclusive approach for isolated atrioventricular valve disease.

Evolving techniques for mitral valve reconstruction

OBJECTIVE

To analyze the effectiveness of new techniques of mitral valve reconstruction (MVR) that have evolved over the last decade, such as aggressive anterior leaflet repair and minimally invasive surgery using an endoaortic balloon occluder.

SUMMARY BACKGROUND DATA

MVR via conventional sternotomy has been an established treatment for mitral insufficiency for over 20 years, primarily for the treatment of patients with posterior leaflet prolapse.

METHODS

Between June 1980 and June 2001, 1,195 consecutive patients had MVR with ring annuloplasty. Conventional sternotomy was used in 843 patients, minimally invasive surgery in 352 (since June 1996). Anterior leaflet repair was performed in 374 patients, with increasing use over the last 10 years. Follow-up was 100% complete (mean 4.6 years, range 0.5-20.5).

RESULTS

Hospital mortality was 4.7% overall and 1.4% for isolated MVR (1.1% for minimally invasive surgery vs. 1.6% for conventional sternotomy; =.4). Multivariate analysis showed the factors predictive of increased operative risk to be age, NYHA functional class, concomitant procedures, and previous cardiac surgery. The 5-year results for freedom from cardiac death, reoperation, and valve-related complications among the 782 patients with degenerative etiology are, respectively, as follows ( >.05 for all end points): for anterior leaflet repair, 93%, 94%, 90%; for no anterior leaflet repair, 91%, 92%, 91%; for minimally invasive surgery, 97%, 89%, 93%; and for conventional sternotomy, 93%, 94%, 90%.

CONCLUSIONS

These findings indicate that late results of MVR after minimally invasive surgery and after anterior leaflet repair are equivalent to those achievable with conventional sternotomy and posterior leaflet repair. These options significantly expand the range of patients suitable for mitral valve repair surgery and give further evidence to support wider use of minimally invasive techniques.

Robotically controlled video-assisted port-access mitral valve surgery

From 1997 to 2000, 221 patients underwent mitral valve surgery through a mini-thoracotomy, using a port-access endovascular cardiopulmonary bypass system in 38 and a transthoracic clamp in 183. In 120 patients, exposure of the mitral valve was facilitated by an endoscope attached to a voice-controlled robotic arm (AESOP 3000). The mitral valve was repaired in 26 patients and replaced in 195; 24 were redo cases. Operating time was 3.5 +/- 1.2 hours, aortic crossclamp time was 58 +/- 16 minutes, intensive care unit stay was 22 +/- 7 hours, and hospital stay was 6.4 +/- 1.2 days. Median postoperative blood loss was 332 +/- 104 mL. There was 1 hospital death. On follow-up at 16.4 +/- 12.2 months, there was no late death or reoperation. New York Heart Association functional class improved from 2.6 +/- 0.5 to 1.4 +/- 0.8. Use of video and robotic assistance minimized incision length and allowed visualization of the whole mitral valve apparatus. The transthoracic clamp facilitated aortic crossclamping and injection of cardioplegia. These findings indicate that the procedure is safe and effective and suggest advantages over conventional surgery in terms of cost, cosmesis, blood loss, postoperative discomfort, intensive care unit and hospital stay.

Minimally invasive valve surgery

BACKGROUND

Cardiac surgery has been the last area of clinical surgery to adopt and embrace minimally invasive surgical techniques. Since the onset of arterial embolectomy in 1965, arthroscopic knee surgery performed in 1975 and laparoscopic cholecystectomy in 1985, huge advances in videoscopic, thorascopic and small incision surgery has taken place in all specialties which now allow change in the traditional approaches to cardiac valve surgery. In 1996, the Brigham and Women's Hospital, along with other units, began minimally invasive cardiac valve surgery for patients who had isolated valve pathology without coronary disease. Our experience now totals 689 patients, including 353 minimally invasive mitral valve repair/replacements and 336 minimally invasive aortic valve replacements, including root replacement and reoperations.

METHODS

This new operative approach involves smaller incisions, the mandatory use of transesophageal echocardiogram for the monitoring of operation quality and air removal, newer perfusion techniques and some modifications in the standard valve repair/replacement techniques. With this blending of TEE, better perfusion techniques and new exposure, the safety and quality of valve operations by these techniques have been excellent.

RESULTS AND CONCLUSION

The operative mortality is equal to (AVR) or less than (MVP) conventional open sternotomy cases and there is a shorter length of stay in the ICU and post-ICU, leading to a lower cost than conventional procedures. There are also less blood transfusions, atrial fibrillation and posthospital rehabilitation requirements, and patients have indicated that there is a faster return to normality over the conventional operative approaches. This brief report summarizes our experience from July, 1996 to January 2001.

Impact of minimally invasive valvular heart surgery: a case-control study

BACKGROUND

The port access (PA) approach for valvular heart surgery is widely used, but few studies evaluating outcomes compared with the sternotomy approach have been performed.

METHODS

One hundred nine consecutive patients undergoing PA-isolated valve surgery were compared with 88 matched patients who underwent sternotomy-isolated valve surgery before the institution of the PA program. Case matching was performed by age, surgeon, congestive heart failure, position of operated valve, and history of previous surgery.

RESULTS

Analysis revealed that PA was associated with similar hospital mortality (p = 0.62), longer bypass times (p < 0.001), shorter length of stay (p = 0.02), fewer transfusions (p = 0.02), and fewer septic complications (p = 0.05).

CONCLUSIONS

The PA approach for isolated valvular heart surgery provided patients with significantly improved clinical outcomes in their immediate perioperative course. Further studies are required to measure the impact of the PA approach on the patients' recovery after hospitalization.

Partial upper re-sternotomy for aortic valve replacement or re-replacement after previous cardiac surgery

OBJECTIVE

We developed techniques for 'inverted T' partial upper re-sternotomy for aortic valve replacement (AVR) or re-replacement (AVreR) after previous cardiac surgery. We previously reported on decreased blood loss, transfusion requirements and total operative duration when compared to conventional full re-sternotomy. This report updates our series, one of the few to document a substantial benefit from a 'minimally-invasive' approach, refines a number of technical aspects of this new approach and reports follow-up.

METHODS

Between November 1996 and December 1999, we performed 34 AVRs or AVreRs after previous cardiac surgery by use of an 'inverted T' partial upper re-sternotomy. There were 25 (74%) men. Median ejection fraction was 54%, range 15-80%. Median age was 72, range 38-93. All were New York Heart Association functional class (NYHA) functional class II or III. Twenty-one (62%) had previous coronary artery bypass grafts (CABG) while 14 (41%) had previous valve surgery. Follow-up was 100% complete for a total of 593 patient months (median 19 months).

RESULTS

Twenty-three (66%) underwent AVR of the native aortic valve while 11 (33%) underwent AVreR of a prosthetic aortic valve. There were no intraoperative or valve-related complications, and no conversion to full re-sternotomy was necessary. There were two (5.9%) operative deaths from an arrhythmia on postoperative day 4 and a large stroke during surgery, respectively. Twenty-four (75%) patients were free of major complications. There was no need for reoperation for bleeding and patients required a median of two units of packed red blood cells. Complications included new atrial fibrillation (n=3, 9%), pacemaker implantation (n=3, 9%) and deep sternal wound infection (n=2, 6%). Median lengths of stay in the intensive care unit (ICU) and in the hospital were 1 and 7 days, respectively. There was one (3%) late deep sternal wound infection and 2/32 (6%) late deaths due to congestive heart failure at 22 months and myocardial infarction at 23 months, respectively.

CONCLUSIONS

Partial upper re-sternotomy presents a safe and effective alternative approach to AVR and AVreR after previous cardiac surgery, and is associated with low morbidity and mortality.

Do patients want minimally invasive aortic valve replacement?

OBJECTIVE

Access to aortic valve can be performed through small incisions. However, a considerable advantage of this approach has not been proven by randomized studies so far. We wanted to elucidate the opinion of patients when they are informed objectively about advantages and disadvantages of minimally invasive approach prior to operation.

METHODS

This prospective study was performed with 27 patients undergoing isolated aortic valve replacement. These patients were informed prior to operation by the same resident concerning objective data. A photograph was shown illustrating a patient with postoperative wound after a standard- and a mini-incision, respectively. After the interview the patient could decide between full and partial sternotomy.

RESULTS

After the interview 21/27 (78%) patients preferred to have a full sternotomy (group F) and 6/27 (22%) patients (group P) decided to have a partial sternotomy. Comments of group F: surgeon should have best exposure (n=15); cosmetics aspects unimportant (n=14); operation time as short as possible (n=7). Group P: cosmetic aspects important (n=6). Significant differences between groups (group F vs. group P): age (years), 69.1+/-1.5 vs. 49.2+/-7.3 (P=0.024); operation time (min), 142+/-7 vs. 189+/-15 (P=0.002); CK (IU/l), 111+/-11 vs. 374+/-114 (P=0.0007); CKMB (IU/l), 17+/-2 vs. 45+/-17 (P=0.006); ICU-stay (days), 2.6+/-0.2 vs. 3.2+/-0.2 (P=0.044). Pericardial effusion requiring drainage was observed in two patients of group P. One patient of group P suffered myocardial infarction.

CONCLUSION

When patients are informed objectively about advantages and disadvantages of minimal invasive aortic valve surgery only a smaller number decides to have a mini incision. The patients preferring short incisions are significantly younger since cosmetic aspects are more important. Longer duration of operation may be due to longer hemostasis based on limited exposure. Air bubbles due to inadequate de-airing might be responsible for higher CK and CK-MB levels in group P.

Minimally invasive video-assisted mitral valve surgery: from Port-Access towards a totally endoscopic procedure

Right thoracotomy is an alternative to mid-sternotomy for left atrium access. The Port-Access approach is an option that reduces the skin incision and obviates rib spreading.

PATIENTS AND METHODS

From February 1997 until November 1999, 121 patients underwent mitral valve surgery through a right antero-lateral thoracotomy using the Heartport cardiopulmonary bypass (CPB) system. Mean age was 60 years (31-84). Most patients had normal ejection fractions and were in NYHA Class II or III. Seventy-five patients had valve repair (62%) and 46 (38%) had valve replacement. Pathologies were myxoid (n = 80), rheumatic (n = 30), chronic endocarditis (n = 5), annular dilatation (n = 3), sclerotic (n = 1), ingrowing myxoma (n = 1), and one closure of a paravalvular leak.

RESULTS

Two patients had conversion to sternotomy for aortic dissection (one died) with the Endo-Aortic Clamp, and two others for peripheral vascular problems. One patient died at postoperative day 1 after reoperation for failed repair, another with double valve surgery on postoperative day 4 after two revisions for bleeding. Twelve underwent revision for bleeding (10%). Three had prolonged ICU stay for respiratory insufficiency. Two late valve replacements for endocarditis occurred. Echographic control revealed residual insufficiencies (grade 1-2) in two valvular repairs. There were neither paravalvular leaks nor myocardial infarcts. There were no cerebrovascular accidents due to embolic phenomena. Mean ICU and hospital stay were 2.1 and 8.7 days, with a major difference between the first 30 patients and those who followed.

CONCLUSION

Port-Access mitral valve surgery can be a valid alternative to conventional sternotomy and seems to be an important improvement in minimally invasive cardiac surgery.

Minimally invasive direct access heart valve surgery

We review our experience with minimally invasive direct access (MIDA) heart valve surgery in 518 patients. Two hundred fifty-two patients underwent MIDA aortic valve replacement (AVR) or repair and 266 underwent MIDA mitral valve repair or replacement. Among the 250 AVRs, 157 (63%) were men, aged 63.2 +/- 14.6 years, NYHA functional Class 2.4 +/- 0.8. The surgical approach was right parasternal in 36 (14%) or upper hemisternotomy in 216 (86%). There were four (2%) operative deaths. Perioperative complications included 14 (5.6%) reexplorations for bleeding, 7 (3%) chest wound infections, 5 (2%) strokes, and 1 (0.4%) external iliac vein injury. Follow-up was complete in 193 (77%) patients, with a mean follow-up of 12 +/- 8 months. Late complications included 2 (0.8%) nonfatal myocardial infarctions, 4 (2%) reoperations for, respectively, 2 pericardial complications, 1 paravalvar leak, and 1 infected valve. There were five (2%) late deaths from congestive heart failure, pneumonia, hemorrhage, aneurysm, and cancer. Mean follow-up NYHA Class was 1.4 +/- 0.6. For the 266 mitral patients, 145 (54.5%) were men, age 58.7 +/- 13.6 years, functional Class 2.3 +/- 0.5. The surgical approach was right parasternal in 195 (73%), lower hemisternotomy in 53 (20%), right submammary thoracotomy in 9 (3.4%), or full sternotomy through a small skin incision in 9 (3.4%). There were 2 (0.8%) operative deaths. Perioperative complications included 4 (1.5%) reoperations for bleeding, 4 (1.5%) strokes, and 5 (2%) wound infections, and 3 (1%) ascending aortic complications. Follow-up was complete in 202 (76%) patients with a mean follow-up of 9.5 +/- 6.4 months. Late complications included one (0.4%) nonfatal myocardial infarction and three (1%) reoperations all converting repairs to replacements. There were three (1%) late deaths from suicide, pneumonia, and sudden death, respectively. Mean follow-up NYHA functional Class was 1.3 +/- 0.5. We conclude that MIDA heart valve surgery is safe and effective for the majority of patients requiring isolated elective aortic or mitral valve surgery.

Reoperative aortic valve replacement: partial upper hemisternotomy versus conventional full sternotomy

OBJECTIVE

We developed techniques for partial upper hemisternotomy for reoperative aortic valve replacement and compared the results with those of reoperative aortic valve replacement by way of conventional full resternotomy.

METHODS

We retrospectively analyzed data from 19 patients who underwent conventional full sternotomy and 20 patients who underwent partial hemisternotomy for isolated elective reoperative aortic valve replacements performed between November 1996 and September 1998. Univariable and multivariable analyses were used to document the differences between the groups.

RESULTS

The 2 groups were similar with respect to age, sex, New York Heart Association functional class, valve pathologic characteristics, and numbers and types of previous operations. There were neither any operative deaths nor any postoperative valve-related morbidities in either group. There was 1 injury to a cardiac structure, which occurred in the conventional full sternotomy group. Univariable analysis documented that patients in the conventional full sternotomy group were significantly more likely to have at least 1000 mL blood loss during the first 24 hours after the operation (odds ratio 8.1, P =.02), were more likely to require transfusion of more than 5 units of packed red blood cell (odds ratio 3.6, P =.08), and were more likely to have a total operative duration longer than 5 hours (odds ratio 3.6, P =.08). In the multivariable analysis conventional full resternotomy remained a risk factor for greater blood loss (odds ratio 5.7, P =.06), greater transfusion requirement (odds ratio 2.4, P =.25), and longer total operative duration (odds ratio 7.7, P =.03).

CONCLUSIONS

Partial upper hemisternotomy for reoperative aortic valve replacement avoids unnecessary lower mediastinal dissection, thereby reducing blood loss, transfusion needs, and total operative duration. These beneficial effects, which are accomplished without compromising the efficacy of the valve operation, make the partial upper hemisternotomy an excellent alternative to conventional full resternotomy for reoperative aortic valve replacement.

Minimally invasive direct access for repair of atrial septal defect in adults

This report documents our early experience with minimally invasive direct-access surgical repair of atrial septal defect (ASD) in adults. We have developed minimally invasive techniques for direct-access ASD repair in adults while maintaining the efficacy of the open operative procedure. Between June 1996 and September 1998, 59 consecutive patients underwent repair of ASD, 34 (58%) of whom underwent minimally invasive direct-access surgical closure of ASD through a right parasternal, submammary, or upper hemisternotomy incision. Twenty-three (68%) were secundum type ASD, 5 (15%) were sinus venosus types, 2 (6%) were primum types, and 4 (122%) were patent foramen ovales. Twenty-six (77%) were women (mean age 39 +/- 15 years, range 18 to 79). The mean pulmonary-to-systemic shunt ratio (Qp/Qs) was 2.3 +/- 0.6 (n = 15). There were no operative or late deaths. Follow-up was 100% complete. Four patients (12%) developed major complications. All were alive and well at the time of follow-up and there was 1 late arrhythmia (atrial fibrillation). In all but 1 patient, New York Heart Association functional class was improved or unchanged (1.47 +/- 0.51 vs 1.06 +/- 0.25, p = 0.0001). These results indicate that minimally invasive direct-access repair of ASD in adults is safe and effective, and is broadly applicable to the entire spectrum of defects.

Minimally invasive mitral valve surgery through right anterolateral minithoracotomy

BACKGROUND

This study evaluates the feasibility of minimally invasive mitral valve surgery. The aim of the study was to minimize surgical access to achieve better cosmetic results, less postoperative discomfort, and faster recovery.

METHODS

From September 1997 to October 1998, 76 patients underwent mitral valve surgery through a right anterolateral minithoracotomy at the fourth intercostal space. The mitral valve was either repaired (n = 21) or replaced (n = 55). In all cases, open femoral artery-femoral vein cannulation was used for cardiopulmonary bypass. In 27 cases, an endoluminal aortic clamp was used, but in 49 cases, the aorta was cross-clamped with a transthoracic, sliding-rod-design clamp.

RESULTS

There were no approach-related limitations to surgical intervention. Intraoperative transesophageal echocardiography revealed excellent results after valve repair and no paravalvular leak in any patient after mitral valve replacement. Mean duration of intensive care and postoperative hospital stay was 32+/-5.2 hours and 7+/-1.1 days, respectively. There were no major complications related to femoral vessel cannulation. In 1 patient, transient neurological problems developed, with subsequent complete recovery. There was one hospital mortality (85-year-old male patient died of upper GI bleeding).

CONCLUSIONS

Minimally invasive port access mitral valve surgery can accelerate recovery and decrease pain, while maintaining overall surgical efficacy. It also provides better cosmetic results to our patients, and now it has become our standard approach for isolated mitral valve surgery.

Current status and future directions of minimally invasive cardiac surgery

The impetus to reduce the trauma of surgery witnessed over the past decade in all fields of surgery has recently extended into the cardiac surgical arena; however, unlike other specialties, the invasiveness of cardiac surgery can be reduced by limiting the size of incisions and by avoiding cardiopulmonary bypass. This article reviews the rationale, clinical experience, and outcomes of the minimally invasive approaches to cardiac surgery that have evolved over the past 2 years and glimpses into the future of this rapidly evolving field.

Minimally invasive direct access mitral valve surgery

We reviewed our experience with minimally invasive direct-access mitral valve surgery in 207 patients through February 1999. Three patients underwent associated procedures, a coronary artery bypass graft (CABG) with right internal mammary artery to right carotid artery (RIMA-RCA), a left ventricular outflow tract (LVOT) debridement for endocarditis, and a primum atrial septal defect (ASD) repair, and were excluded from analysis. Of the 204 remaining patients, 120 (59%) patients were men, aged 58.7 +/- 13.2 years, functional class of 2.3 +/- 0.5. The cause was myxomatous in 162 (79%) patients, rheumatic in 28 (14%) patients, endocarditis in 8 (4%) patients, congenital in 3 (2%) patients, and ischemic in 3 (2%) patients. Mean preoperative EF was 60% +/- 10%, with 184 (90%) patients showing ejection fraction (EF) greater than 50%. The valve was approached through a 5- to 8-cm right parasternal (n = 180, 88%) or right inframammary (n = 24, 12%) incision. One hundred nineteen (58%) patients had open femoral artery-femoral vein cannulation, and 85 (42%) patients had direct cannulation of the aorta and percutaneous cannulation of the femoral vein. One hundred seventy (83%) patients underwent successful valve repair, and 34 (17%) patients required valve replacement. The mean duration of aortic clamping and cardiopulmonary were, respectively, 100 +/- 34 and 146 +/- 44 minutes. There were 2 (1%) surgical deaths. Nonfatal perioperative complications included 3 (1.5%) ascending aortic complications, 3 (1.5%) reoperations for bleeding, 4 (2%) strokes, 2 (1%) transient ischemic attacks (TIAs), 2 (1%) myocardial infarctions, 3 (1.5%) pericardial effusions requiring drainage, 9 (4.5%) vascular complications, and 3 (1.5%) wound complications. Mean length of stay (LOS) was 6.1 +/- 3 days, with 63 (31%) patients being discharged in less than 5 days. One hundred twenty-nine (63%) patients did not require blood transfusions. Follow-up was complete in 165 (81%) patients, with mean follow-up of 13.2 +/- 8 months. Late complications included 1 (0.5%) myocardial infarction, 3 (1.5%) reoperations, all converting repairs to replacements, 3 (1.5%) wound hernias requiring reoperation and repair with mesh, 5 (2.5%) thromboembolic events, and 3 (1.5%) deaths of suicide, pneumonia, and sudden death, respectively. Mean follow-up New York Heart Association (NYHA) functional class was 1.2 +/- 0.5. We conclude that minimally invasive direct-access mitral valve surgery is safe, effective, and applicable for most patients presenting for isolated mitral valve surgery. We now consider it the standard of care for selected patients.