Technical challenges in totally endoscopic robotic coronary artery bypass grafting

Minimal-Access Coronary Revascularization: Past, Present, and Future

Minimal-access cardiac surgery appears to be the future. It is increasingly desired by cardiologists and demanded by patients who perceive superiority. Minimal-access coronary artery revascularisation has been increasingly adopted throughout the world. Here, we review the history of minimal-access coronary revascularization and see that it is almost as old as the history of cardiac surgery. Modern minimal-access coronary revascularization takes a variety of forms-namely minimal-access direct coronary artery bypass grafting (MIDCAB), hybrid coronary revascularisation (HCR), and totally endoscopic coronary artery bypass grafting (TECAB). It is noteworthy that there is significant variation in the nomenclature and approaches for minimal-access coronary surgery, and this truly presents a challenge for comparing the different methods. However, these approaches are increasing in frequency, and proponents demonstrate clear advantages for their patients. The challenge that remains, as for all areas of surgery, is demonstrating the superiority of these techniques over tried and tested open techniques, which is very difficult. There is a paucity of randomised controlled trials to help answer this question, and the future of minimal-access coronary revascularisation, to some extent, is dependent on such trials. Thankfully, some are underway, and the results are eagerly anticipated.

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.

Minimally invasive coronary surgery

Minimally invasive options for coronary artery bypass graft (CABG) surgery progressed dramatically in the last decades. Minimally invasive CABG surgery is presented trough these forms: minimally invasive direct coronary artery bypass (MIDCAB), endoscopic atraumatic coronary artery bypass (EndoACAB), robot-assisted direct coronary artery bypass (RADCAB), total endoscopic coronary artery bypass (TECAB), and hybrid coronary revascularisation (HCR). Unfortunately, these are still limited only to the specialised centres across the world and have not been accepted by the majority of cardiac surgeons. A surgeon who is starting to practice minimally invasive CABG surgery needs to be ready for long duration of the interventions, higher rate of conversions to sternotomy and significant learning curve. Excellent results that have been published on the subject of minimally invasive revascularisation methods support the potential of these alternative approaches to evolve in the near future.

Nonrobotic Total Endoscopic Coronary Artery Bypass Grafting: A Proof-of-Concept Study in 20 Patients

OBJECTIVE

At present, minimal invasive direct coronary artery grafting is the least invasive nonrobotic surgical approach to revascularize the left anterior descending artery with the left internal mammary artery. Total endoscopic coronary bypass grafting is performed with the help of a telemanipulator ("robot"). A prospective proof-of-concept study was initiated to investigate a nonrobotic total endoscopic coronary bypass grafting approach.

METHODS

Twenty patients with significant left anterior descending artery or left main stem lesion were operated on via three or four left thoracic access ports. Under exclusive endoscopic vision, the left internal mammary artery was harvested and anastomosed to the left anterior descending artery manually. Cardiopulmonary bypass and cardioplegic arrest were planned in all cases.

RESULTS

In 10 patients, the operation was completed successfully as nonrobotic total endoscopic coronary bypass grafting. Reasons for conversions to minimal invasive direct coronary artery grafting or conventional sternotomy were dense pleural adhesions (3 patients), bleeding of the anastomosis (3), diffuse bleeding during left internal mammary artery harvesting (2), identification problems of the target artery (1), or left internal mammary artery failure (1). Postoperative angiography in five primarily successful nonrobotic total endoscopic coronary bypass grafting patients showed patent anastomoses in four cases. One patient was reoperated on for early anastomotic failure in a 1.0-mm target vessel. Until now, a percutaneous coronary intervention of remaining lesions as staged hybrid procedure was performed in three patients (2 nonrobotic total endoscopic coronary bypass grafting, 1 minimal invasive direct coronary artery grafting).

CONCLUSIONS

With a thoroughly surveyed learning curve, nonrobotic total endoscopic coronary bypass grafting procedure could become an alternative to other available treatment options; however, the value of the procedure has to be further investigated.

Robotic Totally Endoscopic Coronary Artery Bypass Grafting: Systematic Review of Clinical Outcomes from the Past two Decades

Robotic totally endoscopic coronary artery bypass grafting (TECAB) was introduced in 1998 and has over a period of two decades gradually emerged from single-vessel revascularization to multivessel bypass grafting. Dedicated centers have continuously evolved and further developed this minimally invasive method of coronary bypass surgery. A literature review was conducted to assess intra- and postoperative outcomes of TECAB. PubMed returned 19 comprehensive articles on TECAB. Investigation was focused on perioperative outcome parameters, i.e.: operative time, conversion to larger incision, revision for bleeding, atrial fibrillation, stroke, acute renal failure, and mortality. Outcome from the analysis of 2,397 reported cases showed an average operative time of 291 ± 57 minutes (range 112 to 1,050), conversion rate to larger incisions at 11.5%, and perioperative mortality at 0.8%. Pooled data demonstrated 4.2% operative revision rate due to postoperative hemorrhage, 1.0% stroke incidence, 1.6% acute renal failure, and 13.3% de novo atrial fibrillation. The mean length of hospital stay measured 5.8 ± 1.7 days. Conversion rates and operative times decreased over time. According to data in the literature, coronary bypass surgery carried out in completely endoscopic fashion utilizing robotic assistance can require relatively extensive operative times and conversion rates are somewhat higher than in other robotic cardiac surgery. However, major postoperative events lie in an acceptable range. TECAB remains the surgical revascularization method with the least tissue trauma and represents an opportunity for coronary artery bypass grafting via port access. Rates of major complications are at least similar to conventional surgical access procedures.

A comparative study of three-dimensional high-definition and two-dimensional high-definition video systems in totally endoscopic mitral valve replacement

Background

Three-dimensional vision with improved depth perception and spatial orientation has already proved its superiority to the two-dimensional vision in endoscopic surgery. However, those benefits remain unidentified in cardiac surgery. For the first time, we compare performance of a three-dimensional high-definition video system with a two-dimensional high-definition video system in patients undergoing totally endoscopic mitral valve replacement.

Methods

We enrolled 90 patients with mitral valve disease in a single institution, from June 2013 to June 2016. Totally endoscopic mitral valve replacement was performed by the same surgeon using either a three-dimensional high-definition (n=43) or a two-dimensional high-definition (n=47) video system with the same surgical technique. Short-term outcomes were compared between the two groups. All medical records were retrieved from a prospectively maintained database of minimally invasive cardiac surgery.

Results

All surgeries were successfully completed under totally endoscopic guidance. There were no intraoperative complications in either group. The use of three-dimensional video system reduced aortic cross-clamp time by approximately 10% (3D vs. 2D: 65.74±14.32 vs. 72.67±14.67 min, P=0.027). No significant differences were observed in cardiopulmonary bypass time, postoperative ventilation duration, length of surgical intensive care unit stay, length of hospital stay, and major complications between the two groups. There were no perioperative deaths in either group.

Conclusions

Compared with the two-dimensional video system, the three-dimensional high-definition video system provided a better surgical experience with the same operative safety for totally endoscopic mitral valve replacement.

Hybrid Revascularization: A Review

Hybrid coronary revascularization (HCR) combines surgical bypass with percutaneous coronary intervention (PCI) performed either during the same procedure or in a staged approach within 60 days. Coronary artery bypass grafting using the left internal mammary artery (LIMA) has shown excellent long-term patency with improved patient survival. It remains the gold standard treatment for the majority of patients with multivessel coronary artery disease. However, saphenous vein grafts have poor long-term patency. Advances in stent technology have resulted in reduced rates of thrombosis and restenosis, making PCI a viable alternative to coronary surgery in selected patients. HCR is attractive as a less invasive method of coronary revascularization which preserves the benefits of the LIMA performed with less invasive surgical techniques with the efficacy of newer generation stents.

Robotic-assisted coronary artery bypass surgery: an 18-year single-centre experience

BACKGROUND

Minimally invasive robot-assisted direct coronary artery bypass (RADCAB) has emerged as a feasible minimally invasive surgical technique for revascularization that might offer several potential advantages over conventional approaches. We present our 18-year experience in RADCAB.

METHODS

Between February 1998 and February 2016, 605 patients underwent RADCAB. Patients underwent post-procedural selective graft patency assessment using cardiac catheterization.

RESULTS

The mortality rate was 0.3%. The rate of conversion to sternotomy for any cause was reduced from 16.0% of the first 200 cases to 6.9% of the last 405 patients. The patency rate of the LITA-to-LAD anastomosis was 97.4%. Surgical re-exploration for bleeding occurred in 1.8% of patients, and the transfusion rate was 9.2%. Average ICU stay was 1.2 ± 1.4 days, and average hospital stay was 4.8 ± 2.9 days.

CONCLUSIONS

Robot-assisted coronary artery bypass grafting is safe, feasible and it seems to represent an effective alternative to traditional coronary artery bypass grafting in selected patients.

Comparison of Coronary Artery Bypass Graft-First and Percutaneous Coronary Intervention-First Approaches for 2-Stage Hybrid Coronary Revascularization

Background

Hybrid coronary revascularization (HCR) was developed to combine the advantages of coronary artery bypass graft (CABG) with percutaneous coronary intervention (PCI). However, it is still controversial whether it is more optimal to perform CABG or PCI first. The purpose of this study was to compare the clinical outcomes of these 2 approaches.

Methods

Eighty patients who underwent HCR from May 2010 to December 2015 were enrolled in this retrospective analysis. The CABG-first group comprised 12 patients and the PCI-first group comprised 68 patients. Outcomes of interest included in-hospital perioperative factors, major adverse cardiac and cerebrovascular events (MACCEs), and the incidence of repeated revascularization, especially for the target vessel lesion.

Results

No significant difference was found in the amount of postoperative bleeding (p=0.239). The incidence of MACCEs was similar between the CABG-first and PCI-first groups (1 of 12 [8.3%] vs. 5 of 68 [7.4%], p>0.999). Repeated revascularization was performed on 3 patients (25%) in the CABG-first and 9 patients (13.2%) in the PCI-first group (p=0.376).

Conclusion

There were no significant differences in postoperative and medium-term outcomes between the CABG-first and PCI-first groups. Based on these results, it can be inferred that it is safe to opt for either CABG or PCI as the primary procedure in 2-stage HCR.

Anatomy-based eligibility measure for robotic-assisted bypass surgery

OBJECTIVE

Robotic-assisted endoscopic single-vessel small thoracotomy allows clinicians to perform coronary artery bypass grafting surgery in a minimally invasive manner using the da Vinci Surgical System. Not all patients are suitable for this technique, and the lack of an appropriate method for patient eligibility avoids completion of the procedure robotically. The objective of this study was to develop a patient eligibility method based on the anatomy of the chest of the patient.

METHODS

Preoperative computed tomography thorax scans of 110 patients were analyzed. Two-dimensional measurements taken on the axial images were used with the goal of finding a relation between the anatomy of the patient and the completion of the procedure robotically.

RESULTS

Patients with a distance from the left anterior descending coronary artery to the anterior chest wall of smaller than 15 mm have a 20% probability of requiring conversion of the procedure to open surgery. This probability increases if the chest of the patient is very elliptical, having an anterior-posterior dimension of less than 45% of the transverse dimension.

CONCLUSIONS

The smaller the distance is from the left anterior descending artery to the anterior chest wall, the lower the chances are of completing the procedure robotically.

Robotically assisted coronary artery bypass grafting: a systematic review and meta-analysis

BACKGROUND

It remains uncertain as to whether robotically assisted coronary bypass surgery (RACBS) is superior to non-robotic procedures.

METHODS

Literature searches were conducted using MEDLINE, EMBASE and LILACS. Two review authors independently screened citations, assessed trial quality and performed data extraction.

RESULTS

Three trials met the inclusion criteria. None was randomized. Compared with non-robotic approaches, RACBS was associated with longer surgical times, shorter intensive care unit and hospital stays, higher extubation rates and lower odds for atrial fibrillation as well as myocardial infarction. There were no differences for the odds of stroke and mortality between the interventions.

CONCLUSIONS

Although robotic-assisted coronary bypass appears to be promising, the study designs were not adequate and may have a high risk of selection bias. There is a need for randomized trials to corroborate the findings and to determine the long-term benefits of RACBS compared with traditional surgical approaches.

Clinical outcomes after hybrid coronary revascularization versus coronary artery bypass surgery: a meta-analysis of 1,190 patients

BACKGROUND

Hybrid coronary revascularization (HCR) represents a minimally invasive revascularization strategy in which the durability of the internal mammary artery to left anterior descending artery graft is combined with percutaneous coronary intervention to treat remaining lesions. We performed a systematic review and meta-analysis to compare clinical outcomes after HCR with conventional coronary artery bypass graft (CABG) surgery.

METHODS

A comprehensive EMBASE and PUBMED search was performed for comparative studies evaluating in-hospital and 1-year death, myocardial infarction (MI), stroke, and repeat revascularization.

RESULTS

Six observational studies (1 case control, 5 propensity adjusted) comprising 1,190 patients were included; 366 (30.8%) patients underwent HCR (185 staged and 181 concurrent), and 824 (69.2%) were treated with CABG (786 off-pump, 38 on-pump). Drug-eluting stents were used in 328 (89.6%) patients undergoing HCR. Hybrid coronary revascularization was associated with lower in-hospital need for blood transfusions, shorter length of stay, and faster return to work. No significant differences were found for the composite of death, MI, stroke, or repeat revascularization during hospitalization (odds ratio 0.63, 95% CI 0.25-1.58, P = .33) and at 1-year follow-up (odds ratio 0.49, 95% CI 0.20-1.24, P = .13). Comparisons of individual components showed no difference in all-cause mortality, MI, or stroke, but higher repeat revascularization among patients treated with HCR.

CONCLUSIONS

Hybrid coronary revascularization is associated with lower morbidity and similar in-hospital and 1-year major adverse cerebrovascular or cardiac events rates, but greater requirement for repeat revascularization compared with CABG. Further exploration of this strategy with adequately powered randomized trials is warranted.

Status quo of hybrid coronary revascularization for multi-vessel coronary artery disease

Hybrid coronary revascularization (HCR) combines bypass grafting of the left anterior descending (LAD) coronary artery with percutaneous coronary intervention (PCI) of non-LAD vessels. HCR has been performed as an alternative to CABG or multi-vessel PCI in thousands of patients since the late 1990s. In this review article, we provide an overview on patient selection, procedural sequence and timing, use of surgical techniques and anti-platelet agents. Additionally, patient recovery, satisfaction, costs and clinical outcomes of individual studies after HCR are evaluated. Future directions are also discussed, including the need for adequately powered randomized trials.

Defining the Learning Curve for Robotic-Assisted Endoscopic Harvesting of the Left Internal Mammary Artery

Objective

Robotic-assisted techniques are continuing to cement their role in coronary surgery, particularly in facilitating the endoscopic harvesting of the left internal mammary artery (LIMA), regardless of how the subsequent bypass grafting is performed. As more surgeons attempt to become trained in robotic-assisted procedures, we sought to better define the learning curve associated with robotic-assisted endoscopic LIMA harvest.

Methods

Between January 2011 and July 2012, a total of 77 patients underwent robotic-assisted minimally invasive direct coronary artery bypass surgery at our institution. The LIMA was harvested endoscopically in all patients, using standard robotic instruments, followed by direct grafting to anterior wall myocardial vessels via a small thoracotomy. Intraoperative times for various components of the procedure were collated and analyzed.

Results

The mean ± SD time taken to insert and position the ports for the robotic instruments was 3.9 ± 1.4 minutes. The mean ± SD LIMA harvest time was 31.8 ± 10.1 minutes, and the mean ± SD total robotic time was 44.2 ± 12.9 minutes. All time variables consistently continued to decrease as the experience of the operating surgeon increased, with the greatest magnitude of improvement being evident within the first 20 cases. The logarithmic learning curves for LIMA harvest time and total robot time during our entire experience were both calculated as 90%, correlating to an expected 10% improvement in performance for each doubling of cases completed.

Conclusions

Coronary surgeons can rapidly become proficient in robotic-assisted endoscopic LIMA harvest, with significant improvement in operative times evident within the first 20 cases completed. These data may be useful in designing appropriate training programs for newer surgeons seeking to gain experience in robotic-assisted coronary surgery.

Systematic review of robotic-assisted, totally endoscopic coronary artery bypass grafting

BACKGROUND

Advancements in surgical robotic technology over the last two decades have enabled coronary artery bypass grafting to be performed totally endoscopically, and have the potential to significantly change clinical practice in the future.

METHODS

A systematic review of studies reporting clinical outcomes of total endoscopic coronary artery bypass grafting (TECABG) was performed.

RESULTS

14 appraised studies included 880 beating heart TECABGs, 360 arrested heart TECABGs, 633 one-vessel operations and 357 two-vessel operations. Patients were generally low-risk. There was a significant learning curve. The weighted means for short-term beating heart and arrested heart TECABG results respectively were: intraoperative exclusion rate of 5.7% and 1.9%, intraoperative conversion rate of 5.6% and 15.0%, all-cause mortality of 1.2% and 0.4%, stroke of 0.7% and 0.8%, myocardial infarction of 0.8% and 1.8%, new onset atrial fibrillation of 10.7% and 5.1% and post-operative reintervention rate of 2.6% and 2.3%. The overall rate of short term postoperative graft patency for beating heart and arrested heart TECABG was 98.3% and 96.4% respectively.

CONCLUSIONS

Appropriate patient selection was important in minimizing the risk of intraoperative and postoperative complications. Short-term outcomes of both beating and arrested heart TECABG were acceptable, but results so far have been heterogeneous. There were fewer studies reporting intermediate to long-term outcomes, but results were encouraging, and further investigation and development of the procedure is warranted.

Lessons learned from robotic-assisted coronary artery bypass surgery: risk factors for conversion to median sternotomy

OBJECTIVE

Robotic-assisted coronary artery bypass is a minimally invasive alternative to traditional coronary artery bypass surgery via median sternotomy with an associated learning curve. The purpose of this study was to investigate the reasons for conversion to sternotomy.

METHODS

From October 2009 to June 2012, two surgeons at one US academic institution performed 271 consecutive robotic-assisted coronary artery bypass procedures. For all cases, isolated, off-pump left internal mammary artery (LIMA) to left anterior descending coronary artery grafting was planned via a 3- to 4-cm sternal-sparing thoracotomy after robotic internal mammary artery harvest and pericardiotomy.

RESULTS

Conversion to sternotomy occurred in 15 of 271 (5.5%) patients. The most common reason was technical difficulty with the anastomosis, which occurred in 6 (40.0%) patients. Others included LIMA dissection, 2 (13.3%); wrong vessel grafted, 2 (13.3%); ventricular fibrillation and cardiac arrest, 1 (6.7%); equipment malfunction, 1 (6.7%); adhesions, 1 (6.7%); and other. Two underwent emergent conversion. Six underwent multivessel bypass after conversion instead of hybrid coronary revascularization. No mortality occurred among converted patients. Two patients had postoperative myocardial infarction and one had a superficial sternal wound infection. Conversion rate was relatively stable among the four different time quartiles (range, 3.0%-7.4%), although the reasons for conversion were different.

CONCLUSIONS

Conversion to sternotomy is an infrequent complication of robotic-assisted coronary artery bypass, most commonly because of technical difficulties during the LIMA harvest and the LIMA to left anterior descending anastomosis. Anatomic and patient variables as well as inherent technical problems with minimally invasive procedures make conversion unavoidable in some patients.

Predicting target vessel location on robot-assisted coronary artery bypass graft using CT to ultrasound registration

PURPOSE

Although robot-assisted coronary artery bypass grafting (RA-CABG) has gained more acceptance worldwide, its success still depends on the surgeon's experience and expertise, and the conversion rate to full sternotomy is in the order of 15%-25%. One of the reasons for conversion is poor pre-operative planning, which is based solely on pre-operative computed tomography (CT) images. In this paper, the authors propose a technique to estimate the global peri-operative displacement of the heart and to predict the intra-operative target vessel location, validated via both an in vitro and a clinical study.

METHODS

As the peri-operative heart migration during RA-CABG has never been reported in the literatures, a simple in vitro validation study was conducted using a heart phantom. To mimic the clinical workflow, a pre-operative CT as well as peri-operative ultrasound images at three different stages in the procedure (Stage(0)-following intubation; Stage(1)-following lung deflation; and Stage(2)-following thoracic insufflation) were acquired during the experiment. Following image acquisition, a rigid-body registration using iterative closest point algorithm with the robust estimator was employed to map the pre-operative stage to each of the peri-operative ones, to estimate the heart migration and predict the peri-operative target vessel location. Moreover, a clinical validation of this technique was conducted using offline patient data, where a Monte Carlo simulation was used to overcome the limitations arising due to the invisibility of the target vessel in the peri-operative ultrasound images.

RESULTS

For the in vitro study, the computed target registration error (TRE) at Stage(0), Stage(1), and Stage(2) was 2.1, 3.3, and 2.6 mm, respectively. According to the offline clinical validation study, the maximum TRE at the left anterior descending (LAD) coronary artery was 4.1 mm at Stage(0), 5.1 mm at Stage(1), and 3.4 mm at Stage(2).

CONCLUSIONS

The authors proposed a method to measure and validate peri-operative shifts of the heart during RA-CABG. In vitro and clinical validation studies were conducted and yielded a TRE in the order of 5 mm for all cases. As the desired clinical accuracy imposed by this procedure is on the order of one intercostal space (10-15 mm), our technique suits the clinical requirements. The authors therefore believe this technique has the potential to improve the pre-operative planning by updating peri-operative migration patterns of the heart and, consequently, will lead to reduced conversion to conventional open thoracic procedures.

Is totally endoscopic coronary artery bypass safe, feasible and effective?

A best evidence topic was written according to a structured protocol. The question addressed was whether totally endoscopic coronary artery bypass (TECAB) is safe, effective and feasible. A total of 171 papers were found, of which eight represented the best evidence. The authors, date, journal, study type, population, main outcome measures and results are tabulated. The da Vinci robotic system was utilized in seven retrospective studies and one multicentre prospective trial, comprising 724 patients undergoing TECAB. Patient-related outcomes, including the incidence of major adverse cardiac events, graft patency and survival, were investigated. From the studies evaluated, TECAB appears to be safe operation with low complication rates and excellent early- and mid-term graft patencies. The incidence of internal thoracic artery injury was documented in four studies and ranged from 0 to 10%. Re-exploration for bleeding was necessary in 1-15% of patients. Conversion to open techniques was performed in 0-24% of cases. There was no in-hospital mortality in the majority of studies, but this reached 2.1% in a large series of 228 patients. Target-vessel reintervention rates varied between 0 and 12.1% according to the institutional experience. Pre- and post-discharge graft patencies were excellent at 93-100 and 92-100%, respectively. Intraoperative variables, such as time taken for internal thoracic artery harvest, anastomosis, cross-clamp, cardiopulmonary bypass (CPB) and the overall operation were as follows: internal thoracic artery harvest time (range 5-187 min), anastomosis time (range 6-82 min), cross-clamp time (range 30-223 min), CPB time (range 41-268 min) and operative time (range 84-600 min). TECAB is a technically demanding and time-consuming procedure associated with a significant learning curve. Proctoring and structured training programmes are currently supported by European and international societies to encourage wider uptake of the procedure. In conclusion, TECAB represents a feasible alternative to conventional coronary artery bypass in selected patients. It is associated with low morbidity and excellent mid-term graft patency. Larger, prospective and multicentre trials are required to assess the long-term and patient-reported outcomes of TECAB.

Does Body Mass Index Affect Outcomes in Robotic-Assisted Coronary Artery Bypass Procedures?

Objective

Obese patients pose unique technical challenges for minimal-access cardiac surgery. We sought to examine the effect of body mass index on short-term outcomes in robotic-assisted coronary surgery.

Methods

From January 2010 to November 2011, a total of 110 consecutive patients underwent robotic-assisted coronary surgery at our institution. All patients had robotic-assisted mobilization of the left internal mammary artery. Some patients then underwent direct coronary anastomosis to the left anterior descending coronary artery via a left mini thoracotomy, whereas others had a complete robotic endoscopic procedure within the closed chest. The short-term outcomes of obese patients (n = 39), defined as body mass index greater than 30 kg/m2, were compared with those of nonobese patients (n = 71).

Results

Mean left internal mammary artery harvest time was longer in obese patients than in nonobese patients (51.03 vs 39.94 minutes; P = 0.007), as was overall operative time (218.15 vs 186.72 minutes; P = 0.034). There were no significant differences in mortality or major morbidity between obese and nonobese patients.

Conclusions

Obesity does not adversely affect short-term outcomes in robotic-assisted coronary surgery, although operative times are somewhat longer for these patients. Robotic-assisted coronary techniques can be safely pursued in obese patients.

Minimally invasive approaches versus conventional sternotomy for aortic valve replacement: a propensity score matching study

Background

The aim of this study is to evaluate our institutional results of the aortic valve replacement through minimally invasive approaches compared with conventional sternotomy.

Materials and Methods

From August 1997 to July 2010, 838 patients underwent primary isolated aortic valve replacement. Of them, 73 patients underwent surgery through minimally invasive approaches (MIAS group) whereas 765 patients underwent surgery through the conventional sternotomy (CONV group). Clinical outcomes were compared using a propensity score matching design.

Results

Propensity score matching yielded 73 pairs of patients in which there were no significant differences in baseline profiles between the two groups. Patients in the MIAS group had longer aortic cross clamp than those in the CONV group (74.9±27.9 vs.. 66.2±27.3, p=0.058). In the MIAS group, conversion to full sternotomy was needed in 2 patients (2.7%). There were no significant differences in the rates of low cardiac output syndrome (4 vs. 8, p=0.37), reoperation due to bleeding (7 vs. 6, p=0.77), wound infection (2 vs. 4, p=0.68), or requirements for dialysis (2 vs. 1, p=0.55) between the two groups. Postoperative pain was significantly less in the MIAS group than the conventional group (pain score, 3.79±1.67 vs. 4.32±1.56; p=0.04).

Conclusion

Both minimally invasive approaches and conventional sternotomy had comparable early clinical outcomes in patients undergoing primary isolated aortic valve replacement. Minimally invasive approaches significantly decrease postoperative pain.

Near infrared fluorescence imaging with ICG in TECAB surgery using the da Vinci Si surgical system in a canine model

BACKGROUND

This study assessed the clinical utility of near-infrared fluorescence imaging using indocyanine green in off-pump beating heart total endoscopic and robotic-assisted coronary artery bypass using the fluorescence imaging system for the da Vinci Si on a canine model for vessel identification, graft patency, and correlation of graft patency with ultrasound transit-time flow measurement probe.

METHODS

Beating heart total endoscopic robotic-assisted coronary artery bypass was performed on eight canine using indocyanine green and fluorescence imaging to identify the internal mammary artery prior to harvesting, the coronary vessel anatomy, and the patency of the beating heart total endoscopic coronary artery bypass anastomosis. Three to four injections of indocyanine green with a dose of 1.25 mg to 2.5 mg were administered per animal. Transit-time flow was measured in each of the dogs.

RESULTS

High definition 3D images were obtained. The camera working distance, indocyanine green dosage, internal mammary artery visualization, coronary artery visualization, patency by indocyanine green injection, and patency by transit-time flow were recorded. Six cases were completed successfully, and all demonstrated correlation between indocyanine green measurements of flow, and the transit-time flow measurement.

CONCLUSION

Use of near-infrared fluorescence with indocyanine green was feasible in our study, and would be of great benefit during total endoscopic robotic-assisted coronary artery bypass using the fluorescence imaging-capable da Vinci Si system to help identify the internal mammary artery, delineate the coronary anatomy, and also determine patency of the anastomoses. This procedure correlated well with transit-time flow measurement.

Multivessel beating heart robotic myocardial revascularization increases morbidity and mortality

OBJECTIVE

The vast majority of reports describing beating heart robotic myocardial revascularization (total endoscopic coronary artery bypass) contain very small numbers of patients undergoing single-vessel bypass. We present a large series of patients undergoing multivessel total endoscopic coronary artery bypass.

METHODS

We performed a retrospective clinical review of 106 patients undergoing total endoscopic coronary artery bypass (72% multivessel) at 1 institution by 1 experienced cardiac surgeon/physician assistant team. These results were compared with the expected clinical outcomes from conventional coronary artery bypass grafting calculated using the Society of Thoracic Surgeons risk calculator.

RESULTS

Of the 106 patients, 1% underwent quadruple total endoscopic coronary artery bypass, 8% triple, 63% double, and 28% single. The emergent conversion rate for hemodynamic instability was 6.6%. The postoperative renal failure rate (doubling of baseline serum creatinine or dialysis required) was 7.5%. Overall, 23 patients (21.7%) exhibited at least 1 major morbidity/mortality (4 deaths). The number of vessels bypassed (single/double/triple/quadruple) correlated positively with the surgical/operating room time, the lung separation time, vasoactive medication use, blood use, a postoperative ventilation time longer than 24 hours, intensive care unit length of stay, and hospital length of stay. An increased surgical time was significantly associated with major morbidity (P = .011) and mortality (P = .043). A comparison with the Society for Thoracic Surgeons expected outcomes revealed a similar hospital length of stay but an increased incidence of prolonged ventilation (P = .003), renal failure (P < .001), morbidity (P = .045), and mortality (P = .049).

CONCLUSIONS

Our results suggest that addressing multivessel coronary artery disease using total endoscopic coronary artery bypass offers no obvious clinical benefits and might increase the morbidity and mortality.

Early and midterm results of totally endoscopic coronary artery bypass grafting on the beating heart

OBJECTIVE

Despite the early introduction of totally endoscopic coronary artery bypass on the beating heart, only a limited number of cases have been performed. The limiting factor has been the concern about safety and graft patency of the anastomosis. This study describes our experience with totally endoscopic coronary artery bypass on the beating heart with robotic assistance and its early and midterm results.

METHODS

In 365 cases of robotic cardiac operations, 162 patients underwent robotic coronary artery bypass grafting on the beating heart, of whom 60 patients (46 male, 14 female) underwent totally endoscopic coronary artery bypass on the beating heart. The patients' mean age was 56.97 ± 9.7 years (33-77 years). Left internal thoracic artery to left anterior descending anastomosis was performed using the U-Clip device.

RESULTS

We completed 58 totally endoscopic coronary artery bypass procedures, in which 16 patients received hybrid procedures. Two patients had conversions to a minithoracotomy. The average left internal thoracic artery harvesting and anastomosis times were 31.3 ± 10.5 (18∼55) minutes and 11.3 ± 4.7 (5∼21) minutes, respectively. The mean operating room and operation times were 336.1 ± 58.5 (210∼580) minutes and 264.8 ± 65.6 (150∼420) minutes, respectively. The drainage was 164.9 ± 83.2 (70∼450) mL. Before discharge, 50 patients underwent angiography and 8 patients underwent computed tomography angiography, and the study showed that graft patency was 100%. Unexpectedly, the left internal thoracic artery graft developed a collateral branch in 2 patients. After discharge, all patients were followed up by computed tomography angiography. The average follow-up time was 12.67 ± 9.43 (1-40) months. One patient had gastric bleeding after surgery.

CONCLUSIONS

Totally endoscopic coronary artery bypass on the beating heart is a safe procedure in selected patients and produces excellent early and midterm patency of anastomosis.

Is an intraaortic balloon pump a contraindication to robotic totally endoscopic coronary artery bypass?

BACKGROUND

The success of robotic totally endoscopic coronary artery bypass (TECAB) in recent years has led to the expansion of the procedure to patients with more severe disease. Outcomes with these patients have not yet been well characterized, and no reports on TECAB performed in patients with a preoperatively placed intraaortic balloon pump (IABP) are available. We present our initial experience with this patient population.

PATIENTS AND METHODS

We evaluated 5 patients with unstable angina or impaired left ventricular function requiring a preoperatively placed IABP who underwent TECAB using the daVinci telemanipulation system. Procedures were performed either on the beating heart using an endostabilizer (n = 2) or on the arrested heart using remote access perfusion and aortic balloon endoocclusion (n = 3). The median patient age was 67 years (range, 41-73 years), with a median preoperative ejection fraction of 43% (range, 26%-58%) and median EuroSCORE of 5 (range, 3-8).

RESULTS

There were no major intraoperative technical issues. The median length of stay in the hospital and intensive care unit was 8 days (range, 5-13 days) and 66 hours (range, 41-142 hours), respectively. There were no intraoperative or 30-day mortalities.

CONCLUSIONS

This early experience suggests that TECAB is feasible in patients with a preoperatively placed IABP. Both the beating heart and arrested heart versions can be used in this patient population, further broadening the spectrum of applicability of this procedure.

Preoperative Evaluation of Patient Anatomy to Increase Success of Robotics-Assisted Bypass Surgery

Objective

Robotics-assisted endoscopic atraumatic coronary artery bypass has been shown to be effective in reducing surgical morbidity and length of hospital stay. Unfortunately, the criteria for selecting eligible patients for this procedure are still primitive. This has motivated the use of preoperative computed tomography scans to establish patient eligibility. The objective of this study is to establish which image measurements can be correlated to procedure success.

Methods

A retrospective study was performed in 144 patients who underwent robotics-assisted coronary bypass surgery. After an initial set of 55 patients, preoperative computed tomography scans of the other patients were used to obtain patient specific measurements: the lateral distance between the midline of the sternum to the left anterior descending coronary artery and its depth from the skin surface, anteroposterior diameter of the thoracic cavity, and the transverse diameter of the thoracic cavity. The procedures were rated as successful if completed in a minimally invasive manner. Different combinations of the variables were evaluated and correlated with success.

Results

A strong correlation was found between success rate and the ratio of the lateral distance to the transverse diameter in the female patients only (0.532, P = 0.006). A ratio of less than 0.20 significantly increased the occurrence of conversion during this procedure in female cases.

Conclusions

The lateral distance of the left anterior descending coronary artery from the midline divided by the transverse thoracic width of a female patient shows a significant correlation with procedure success. No significant correlations were found for male patients.

Factors influencing blood transfusion requirements in robotic totally endoscopic coronary artery bypass grafting on the arrested heart

OBJECTIVE

Robotic technology enables totally endoscopic coronary artery bypass grafting (TECAB) procedures. These operations can be performed on either the beating or arrested heart. One challenge of the latter version is a potentially increased need for blood transfusions. We investigated factors associated with transfusion requirements in totally endoscopic coronary artery bypass on the arrested heart (AH-TECAB).

PATIENTS AND METHODS

A total of 161 patients, 124 males and 37 females, aged 59 (31-77 years) years, with European System for Cardiac Operative Risk Evaluation (EuroSCORE) 1 (0-7) underwent AH-TECAB using the daVinci telemanipulation system. The Heartport/Cardiovations™ or ESTECH-RAP™ systems were applied for remote access perfusion and aortic endoocclusion. In all cases, the operation was carried out in moderate hypothermia and cardiac arrest using cold crystalloid cardioplegia mixed with blood.

RESULTS

After 20 cases, the blood-transfusion rate dropped from 69% to 44%. The overall median number of transfusions was 1 (0-21). The following pre- and intra-operative factors showed a strong association with the application of packed red blood cells (PRBCs): preoperative haemoglobin level (p < 0.001), female gender (p < 0.001), shorter height (p < 0.001), lower weight (p < 0.001), long operative time (p < 0.001) and long cardiopulmonary bypass time (p = 0.001), intra-operative surgical problem (p < 0.001) and conversion to a larger thoracic incision (p < 0.001). Postoperatively, patients with longer ventilation time (p < 0.001) and those needing revision for bleeding (p < 0.001) also received significantly more PRBCs.

CONCLUSION

We conclude that multiple factors are associated with increased blood transfusion requirements in AH-TECAB. However, the transfusion rate can be reduced with experience. Identification of these factors may help in avoiding the application of blood products in the next generation of AH-TECAB procedures.

The implementation of an integrated computer-assisted system for minimally invasive cardiac surgery

BACKGROUND

Preoperative planning and surgical navigation are two crucial aspects of a computer-assisted system for the success of minimally invasive cardiac surgery.

METHODS

In the first part, port placement planning was mainly discussed. We proposed an algorithm based on four criteria to achieve optimized placement. In the second part, an optical tracker was used to locate the thoracoscope and surgical instruments accurately and to show the relative positions between the thoracoscope, surgical instruments and the patient's anatomical structures. An image-matching technique was employed to help the surgeon locate the target, using real-time thoracoscopic video images during the procedure.

RESULTS

In order to verify our proposed algorithms, several clinical planning cases were performed to compare our port placement algorithm to the traditional method. Both phantom test and animal study experiments were also done to demonstrate the validity of the target tracking of the system. Both the phantom test and the animal study revealed that the fiducial registration error (FRE) was 1.08 +/- 0.16 mm and system error was 5.05 +/- 0.67 mm, respectively.

CONCLUSION

A novel computer-assisted system for minimally invasive cardiac surgery has been developed. This method has shown its capability to achieve the preoperative planning and real-time surgery navigation.