Minimally invasive cardiac surgery.

Cardiac surgery has been the last of the surgical specialties to embrace the principles of minimal invasiveness. The complexity and invasiveness of the procedures have presented both a problem and an opportunity to make the procedures less invasive. Beginning with initial attempts at coronary artery bypass surgery through limited access with and without robotics, a number of other cardiac procedures currently are being performed by minimally invasive approaches. These include mitral valve repair, transapical aortic valve implant, limited access, and totally endoscopic pulmonary vein isolation for the treatment of atrial fibrillation and the treatment of aortic aneurysmal disease by thoracic endografting. The experience with less invasive surgery in other specialties has served as cross-fertilization for minimally invasive cardiac surgery.

Beating heart surgery reduces mortality in the reoperative bypass patient.

BACKGROUND: Reoperative coronary artery bypass grafting (redo-CABG) has an increased operative morbidity and mortality compared to patients undergoing primary revascularization. In an effort to reduce the hazards of reoperative CABG, we commenced revascularizing selected patients without cardiopulmonary bypass (CPB) as an alternative to conventional approaches. METHODS: From January 1998 to Dec. 2000, 432 patients underwent reoperative CABG, 153 patients (35%) without the aid of CPB. Treatment groups were compared by means of univariate analysis for preoperative risk factors and postoperative complications. Predicted risk and risk-adjusted mortality were determined by the Society of Thoracic Surgeons risk algorithm. RESULTS: There was a significant difference in the preoperative predicted risk scores between the two treatment groups (off pump 6.5% vs. on pump 5.4%, p=0.0343). There was a significant difference in the off pump observed mortality (2.61%) versus the on pump group (9.68%, p=0.0065). Decreased morbidity in the off pump group was evidenced by a reduced need for blood products (25% vs. 67%, p<0.0001), and the incidence of prolonged ventilation (4% vs. 14%, p=0.0032). The off pump group also had shorter hospital stays (6.2 +/- 5.96 days vs. 8.0 +/- 7.82, p=0.0091). No significant differences between the two groups were seen in the prevalence of perioperative myocardial infarction, stroke, renal failure, or reoperation for bleeding. CONCLUSION: Bypass grafting without CPB significantly decreases mortality and morbidity in selected reoperative patients, and should be considered a viable alternative to conventional approaches.

Initial prospective multicenter clinical trial of robotically-assisted coronary artery bypass grafting.

BACKGROUND: This multicenter prospective trial was designed to assess the safety and efficacy of using a robotically-assisted microsurgical system to create endoscopic coronary anastomoses. METHODS: . Thirty-two patients scheduled for elective primary coronary surgery underwent endoscopic anastomosis of the left internal thoracic artery (LITA) to the left anterior descending (LAD) artery. Three thoracic ports (two for instruments and one for a camera) were placed, and a robotic system was used to perform the LITA-LAD graft. Conventional techniques were used to perform the other grafts. Thirty-one patients underwent median sternotomy and 1 patient underwent a limited anterior thoracotomy. RESULTS: . Graft flow was measured in the operating room and averaged 37 +/- 19 mL/min. Mean anastomosis time was 24 +/- 9 minutes. There were three intraoperative revisions (9%). Two were for inadequate flow and one for an inadvertent injury. Each of these grafts was successfully revised by hand. There were no technical failures of the robotic system. Average postoperative length of stay was 5.5 +/- 2.7 days. There were three reoperations for bleeding, but none of these were related to the LAD anastomosis. Two months following the operation, selective angiography revealed a graft patency of 93%. The patients have been followed for 16 +/- 4 months. CONCLUSIONS: This initial prospective multicenter trial documents the feasibility of robotically-assisted coronary bypass grafting. Further trials are warranted to establish the safety and efficacy of this new technology.

Left mini-thoracotomy for beating heart bypass grafting: a safe alternative to high-risk intervention for selected grafting of the circumflex artery distribution.

BACKGROUND: Progression of disease and bypass graft attrition results in a population of patients who require repeated coronary interventions. Frequently, these patients have patent internal mammary artery grafts and require isolated intervention to the circumflex distribution. As an alternative to high-risk repeated sternotomy and conventional bypass surgery or catheter-based intervention, the circumflex marginal vessels may be approached by thoracotomy. We reviewed our experience in revascularizing the circumflex distribution with off-pump techniques via left mini-thoracotomy. METHODS AND RESULTS: Thirty-two patients underwent off-pump bypass grafting of the circumflex vessels via thoracotomy from December 1995 to April 2000. Twenty-seven patients presented with circumflex disease after having previous bypass grafting. Five patients, who presented with circumflex disease and either nondiseased or ungraftable disease in their other arteries, were revascularized as a primary procedure. There was no observed mortality. Seven patients (22%) required inotropes on leaving the operating room, and 3 patients (9.4%) received transfusion of packed red blood cells. There was 1 reoperation for bleeding and 1 patient with a postoperative neurological deficit. There were no perioperative myocardial infarctions. The average length of stay was 4.8 days from time of surgery to discharge. CONCLUSIONS: Off-pump grafting via thoracotomy provides a safe and effective alternative approach for patients requiring limited revascularization. Potential cardiac injury and danger to viable grafts from repeated sternotomy is minimized, and manipulation of the diseased ascending aorta is avoided. Morbidity, hospital length of stay, and cost are less than for conventional repeated coronary bypass surgery.

Influence of diabetes on mortality and morbidity: off-pump coronary artery bypass grafting versus coronary artery bypass grafting with cardiopulmonary bypass.

BACKGROUND: Myocardial revascularization in diabetic patients is challenging with no established optimum treatment strategy. We reviewed our coronary artery bypass grafting experience to determine the impact of eliminating cardiopulmonary bypass on outcomes in diabetic patients relative to nondiabetic patients. METHODS: From January 1995 through December 1999, 9,965 patients, of whom 2,891 (29%) had diabetes, underwent isolated coronary artery bypass grafting. Diabetic and nondiabetic patients were further divided into groups on the basis of cardiopulmonary bypass use. Twelve percent (346 of 2,891) of diabetic patients and 12% (829 of 7,074) of nondiabetic patients underwent coronary artery bypass grafting without cardiopulmonary bypass; the remainder had coronary artery bypass grafting with cardiopulmonary bypass. Nineteen preoperative variables were compared among treatment groups by univariate analysis. RESULTS: Patients undergoing coronary artery bypass grafting without cardiopulmonary bypass compared with those having coronary artery bypass grafting with cardiopulmonary bypass had higher mean predicted mortalities (diabetic, 3.96% versus 3.72%, p = 0.83; nondiabetic, 3.03% versus 2.86%, p = 0.79). In nondiabetic patients, coronary artery bypass grafting without cardiopulmonary bypass provides an actual and risk-adjusted survival advantage over coronary artery bypass grafting with cardiopulmonary bypass (1.81% versus 3.44%, p = 0.0127; risk-adjusted mortality, 1.79% versus 3.61%, p = 0.007). This survival benefit of coronary artery bypass grafting without cardiopulmonary bypass was not seen in diabetic patients (2.89% versus 3.69%, p = 0.452; risk-adjusted mortality, 2.19% versus 2.98%, p = 0.42). Diabetic patients undergoing coronary artery bypass grafting without cardiopulmonary bypass had fewer complications, including decreased blood product use (34.39% versus 58.4%, p = 0.001), and reduced incidence of prolonged ventilation (6.94% versus 12.10%, p = 0.005), atrial fibrillation (15.90% versus 23.26%, p = 0.002), and renal failure requiring dialysis (0.87% versus 2.75%, p = 0.036). CONCLUSIONS: The survival advantage in nondiabetic patients treated with coronary artery bypass grafting without cardiopulmonary bypass is not apparent in diabetic patients. Coronary artery bypass grafting without cardiopulmonary bypass in diabetic patients is nevertheless associated with a significant reduction in morbidity.

Off-pump bypass grafting is safe in patients with left main coronary disease.

BACKGROUND: Because of a concern about the ability to tolerate beating heart grafting, patients with left main coronary artery stenosis have been excluded from off-pump bypass. We reviewed our experience with off-pump coronary artery bypass grafting for patients with left main coronary artery disease. METHODS: Eight hundred twenty-three patients underwent bypass grafting for left main coronary artery disease from January 1998 to October 1999. One hundred patients were revascularized without the use of cardiopulmonary bypass and compared with a contemporaneous cohort of 723 patients who underwent grafting with the aid of cardiopulmonary bypass. All patients had multivessel grafting performed through a sternotomy. RESULTS: There was one death (1%) in the group undergoing off-pump grafting as compared with a 30-day mortality of 4.7% (p = 0.059) in the on-pump group. Univariate analysis established that patients revascularized without cardiopulmonary bypass were significantly less likely to require postoperative inotropic support (23% versus 62%, p < 0.001) and transfusion (35% versus 67%, p < 0.001). Logistic regression analysis revealed that cardiopulmonary bypass was an independent risk factor for mortality (odds ratio, 7.3; 95% confidence interval, 1.34 to 138.4). CONCLUSIONS: Coronary artery bypass grafting using off-pump techniques are safe and effective in left main coronary artery disease.

Comparing clinical outcomes in high-volume and low-volume off-pump coronary bypass operation programs.

UNLABELLED: sites and then analyzed the patient and hospital characteristics that had an impact on clinical outcomes. RESULTS: The mortality rates for the high- and low-volume OPCAB facilities both averaged 2.9% (p = NS). Patients at the high-volume OPCAB facilities had significantly lower rates of major complications (shock/hemorrhage, neurologic, renal, and cardiac) than those at the low-volume OPCAB facilities. Of the seven minor complications, rates for six were lower in the high-volume OPCAB facilities, but none of the differences reached statistical significance. High-volume OPCAB sites were significantly more likely to discharge their patients directly home than were low-volume OPCAB sites (80% versus 66%; p = 0.001). CONCLUSIONS: The results suggested that surgical team experience and choice of approaches to performing CABG had an impact on patient outcomes.

Video-assisted thoracoscopy thymectomy for myasthenia gravis.

Over the past 8 years, the technique of video-assisted thoracoscopic surgery (VATS) thymectomy has continued to evolve. Although the procedure has become better defined and greater experience has been gained, numerous issues still exist. Whether it is best performed through a left sided, right sided, or as a bilateral approach with or without a cervical incision, is not clear. Equivalence of outcomes compared with more standard approaches to thymectomy is still an issue. Experience still is relatively limited to a few centers, and follow-up still is relatively short. In the author's own experience, it seems that availability of the less invasive approach has allowed thymectomy to be performed earlier in the course of the disease especially in young female patients in whom cosmesis is an important issue.

Venoarterial air embolus: a complication of vacuum-assisted venous drainage.

Minimal access techniques with cardiopulmonary bypass use smaller cannula systems for management of cardiopulmonary bypass. To augment flow rates through the smaller cannula, the technique of vacuum-assisted venous drainage has been used. We describe a complication of vacuum-assisted venous drainage by inadvertent positive pressurization of the venous circuit resulting in a paradoxic air embolus across a patent atrial septal defect. Hazards of the current cardiopulmonary bypass systems and techniques for avoiding this potential complication are discussed.

Minimally invasive and robotic surgery.

Advances in surgery have focused on minimizing the invasiveness of surgical procedures, such that a significant paradigm shift has occurred for some procedures in which surgeons no longer directly touch or see the structures on which they operate. Advancements in video imaging, endoscope technology, and instrumentation have made it possible to convert many procedures in many surgical specialties from open surgeries to endoscopic ones. The use of computers and robotics promises to facilitate complex endoscopic procedures by virtue of voice control over the networked operating room, enhancement of dexterity to facilitate microscale operations, and development of virtual simulator trainers to enhance the ability to learn new complex operations. Future research will focus on delivery of diagnostic and therapeutic modalities through natural orifices in which investigation is under remote control and navigation, so that truly "noninvasive" surgery will be a reality.

Therapeutic video-assisted thoracoscopic surgical resection of colorectal pulmonary metastases.

OBJECTIVE: Careful patient selection is vital when video-assisted thoracoscopic surgical (VATS) therapeutic pulmonary metastasectomy of colorectal carcinoma is considered. Complete resection of all metastatic disease remains a vital concept. We reviewed our VATS experience for therapeutic metastasectomy of peripheral colorectal pulmonary metastases. METHODS: Over 90 months, therapeutic VATS metastasectomy was accomplished upon 80 patients with colorectal metastases. Thin cut computed tomography (CT) was central in identifying lesions. The mean interval from primary carcinoma to VATS resection was 41 months (1-156 months; median, 33). A solitary lesion was resected in 60 patients and multiple (2-7) lesions resected in 20 patients. Statistics were obtained using the Student's t-test. RESULTS: No operative mortality or major postoperative complications occurred. The hospital stay was 4.5+/-2. 2 days (range, 1-13). All lesions were resected by VATS, with four conversions to thoracotomy to improve the margins. The mean survival of patients with one lesion was 34.8 months compared with 26.5 months for patients with multiple lesions (P=0.37). The mean survival was 20.5 months when metastases occurred <3 years vs. 28.1 months for >3 years from primary carcinoma resection (P=0.20). Twenty-five (31%) patients are disease free; with a mean interval of 38.7 (3-84; median, 35) months. Sixty-nine percent (55/80) of patients developed a recurrence: 6/80 (8%) local; 19/80 (24%) regional (same hemithorax away from resection); and 30/80 (38%) distant. The overall survival at 1 year was 81.2%, 48.4% at 3 years and 30.8% at 5 years. CONCLUSIONS: Therapeutic VATS resection of colorectal metastases appears efficacious. Preoperative CT can identify peripheral colorectal metastases amenable to VATS. Conversion to thoracotomy is indicated when none of the lesions identified by CT are found or when clear surgical margins are jeopardized.

Lung cancer. Surgical approaches and incisions.

With the emphasis of current surgical practice being increasingly focused on reducing the invasiveness of procedures, new techniques and concepts are changing the approach to thoracic surgery. Robotics offers the benefits of scaled motion, tremor filtration, and remote telemanipulation. It may be theoretically possible to introduce the concept of telementoring into thoracic surgery. By coupling two consoles, it would be possible for a senior surgeon to guide a junior surgeon through an endoscopic procedure in which the clinicians were in different locations. The use of telepresence surgery would also enable surgeons to perform or assist in operations taking place in remote locations. Robotics has the potential to increase the applicability of endoscopic surgery to an increasing number of patients with technically complex thoracic problems. Given that this technology is in its infancy, it remains too early in the process to determine if robotics will be a significant "value-added" element of cardiothoracic surgery; however, the possibilities continue to be limited only by imagination and ingenuity.

Coronary Surgery: off-pump and port access.

Attempts to minimize the invasiveness of cardiac surgery have focused on decreasing access trauma and eliminating cardiopulmonary bypass. The initial procedures, minimally invasive direct coronary artery bypass (MIDCAB, limited access beating heart) and port access (limited access arrested heart), have become niche procedures. Off-pump coronary artery bypass (OPCAB, median sternotomy beating heart) presently accounts for approximately 15% of all coronary bypass operations performed in the United States. Morbidity and cost appear to be decreased with these procedures. Feasibility trials of endoscopic coronary bypass surgery using robotic devices are underway in many centers. It is anticipated that over the next 5 years the alternative approaches to conventional coronary artery bypass surgery will continue to grow as methods of coronary revascularization.

Analysis of hemodynamic changes during beating heart surgical procedures.

BACKGROUND: Coronary artery bypass grafting on the beating heart causes significant hemodynamic compromise during displacement of the heart. The precise mechanisms causing altered hemodynamics have not been clearly understood. The purpose of this study was to define the hemodynamic changes caused by displacing the heart in patients undergoing beating heart surgical procedures. METHODS: Forty-four patients (35 men, 9 women; mean age, 64.5 +/- 9.6 years) underwent off-pump coronary artery bypass grafting. The hemodynamic variables were collected before and after positioning the heart for anastomosis of the left anterior descending, circumflex, and posterior descending coronary arteries. RESULTS: There was a significant increase in right ventricular end-diastolic pressure during positioning for all vessels, and in left ventricular end-diastolic pressure during positioning for the left anterior descending and circumflex coronary arteries. Positioning for the circumflex artery showed the largest increase of left and right ventricular end-diastolic pressure, resulting in the greatest hemodynamic compromise. CONCLUSIONS: In the clinical setting of diseased human hearts, there is a biventricular contribution to altered hemodynamics. The increase of right ventricular end-diastolic pressure in all positions suggests that the major cause of hemodynamic changes is disturbed diastolic filling of the right ventricle, especially by direct ventricular compression.

A review of 1,582 consecutive Octopus off-pump coronary bypass patients.

BACKGROUND: Off-pump coronary bypass may provide a safer form of surgical revascularization by avoiding the unwanted complications of cardiopulmonary bypass, particularly in the increasingly complex patients being referred for operation. This study reviews the entire experience of the Medtronic Octopus System (Medtronic, Minneapolis, MN) for beating heart bypass from 7 surgeons. Demographics, operative procedures, early outcomes, and trends in usage were examined. METHODS: Patients were selected for off-pump procedures by the individual surgeons. Data were entered prospectively into locally maintained databases and then collected for collation and analysis. RESULTS: A total of 1,582 consecutive Octopus patients were entered, representing the entire Octopus experience of each surgeon. Proportions of off-pump procedures relative to standard bypass increased over time, as did the percentage of patients receiving three or more grafts, 24.6% in 1997 and 55.9% in 1999. A total of 3,653 anastomoses were performed, 1,905 to the left anterior descending system, 837 to the circumflex distribution, and 911 to the right coronary territory. Morbidity was low. Few patients required conversion to cardiopulmonary bypass (2.6%; 0.2% urgently). Permanent stroke occurred in 0.6% and myocardial infarction in 1.2%. Operative mortality was 1%. CONCLUSIONS: Octopus off-pump bypass was demonstrated to be a safe procedure with widening applicability. With experience surgeons tend to apply the system to increasing proportions of their patients and are able to revascularize all coronary territories.

Right heart circulatory support facilities coronary artery bypass without cardiopulmonary bypass.

BACKGROUND: Revascularization of the posterior wall often causes hemodynamic instability in beating heart coronary artery bypass (CAB). Our previous clinical studies have shown that tilting the heart primarily alters right-heart hemodynamics. The purpose of this study was to evaluate right-heart support in clinical cases. METHODS: Seventeen patients underwent beating heart CAB with right-heart support. The right-heart support system (A-Med Systems, West Sacramento, CA) consisted of a coaxial cannula placed through the right atrium and the tip of the cannula positioned in main pulmonary artery. Blood was removed from the right atrium and returned to the main pulmonary artery. RESULTS: Elective beating heart CAB was accomplished successfully in 17 patients with right-heart support. Anastomoses performed were left anterior descending coronary artery (11), diagonal (3), circumflex (5), obtuse marginal artery (11), and right coronary artery (10). Right-heart support between 1 and 3 L/min improved hemodynamics especially in the circumflex position. No device-related patient incidents occurred, nor were there incidents of infection or air embolism. All 17 patients were discharged to their homes. CONCLUSIONS: The right-heart support system was safe without complications. Exposure of the posterior wall was possible in all cases without hemodynamic compromise.