Biomedical subjects

Volkmar Falk

Publications and source records attributed to Volkmar Falk.

At least 19 recordsLinked to original sources

PubMed2007

Seven-year follow-up after minimally invasive direct coronary artery bypass: experience with more than 1300 patients.

BACKGROUND: Minimally invasive direct coronary artery bypass (MIDCAB) for revascularization of the left anterior descending artery has become a routine operation. Here we present the experience after more than 1300 MIDCAB procedures with up to 7 years of follow-up. METHODS: All patients undergoing standard MIDCAB between 1996 and 2004 were included. Long-term follow-up information about health status, major cardiac and cerebral adverse events, and freedom of angina was collected annually by a questionnaire or personal contact. Preoperative, intraoperative, and postoperative data could be completed for all 1347 patients. Five-year follow-up was available for 450 patients and 7-year follow-up for 194 patients. RESULTS: Mean age was 63.2 years (range, 25 to 92 years) and mean ejection fraction was 0.61 +/- 0.14. In 23 patients (1.7%), intraoperative conversion to sternotomy or CPB, or both, was necessary. Early postoperative mortality was 0.8% (n = 11), and 0.4% (n = 5) had a perioperative stroke. A routine postoperative angiogram in 709 patients showed 95.6% early graft patency. Short-term target vessel reintervention was needed 55 patients (4.1%): 10 had percutaneous transluminal coronary angioplasty/stent and 45 had reoperation. A repeat angiogram at the 6-month follow-up was available in 350 patients and demonstrated 94.3% graft patency. Kaplan-Meier analysis revealed a 5-year survival of 91.9% (95% confidence interval [CI], 90.1% to 93.8%) and a 7-year survival of 89.4% (95% CI, 86.7% to 92.1%). The freedom of major adverse events and angina was 89.5% (95% CI, 87.4% to 91.5%) after 5 years and 83.3% (95% CI, 79.0% to 87.5%) after 7 years. CONCLUSIONS: MIDCAB can be safely performed with low postoperative mortality and morbidity. The excellent short-term and long-term survival as well as freedom from major adverse cardiac and cerebral events and angina compare favorably with stenting and conventional surgery.

Adult↗

PubMed2006

Perspectives in endoscopic cardiac surgery.

Surgical telemanipulators are obviously used in cardiac surgery to provide the surgeon in a confined space the same stereoscopic vision, full dexterity, unimpaired hand-eye alignment and tactile feedback as in open surgery. This is the basic concept that enables the controlled fine soft tissue manipulation that is needed in bypass grafting and valve surgery. In 2005, a total of 2984 cardiac procedures were performed worldwide using the da Vinci system. This includes totally endoscopic coronary artery bypass grafting (TECAB), mitral valve repair (MVR) procedures, ASD closure and cardiac tissue ablation for atrial fibrillation.

Cardiac Surgical Procedures↗

PubMed2006

Minimally invasive transapical beating heart aortic valve implantation--proof of concept.

OBJECTIVE: To evaluate the feasibility of minimally invasive transapical beating heart aortic valve implantation (TAP-AVI) for high-risk patients with aortic stenosis. METHODS: TAP-AVI was performed via a small anterolateral minithoracotomy with or without femoral extracorporeal circulation (ECC) on the beating heart. A pericardial xenograft fixed within a stainless steel, balloon expandable stent (Cribier-Edwards, Edwards Lifesciences, Irvine, CA, USA) was used. Thirty consecutive patients (82 +/- 5.1 years, 21 (70%) female) were operated from 02/06 until 09/06 at one center using fluoroscopic and echocardiographic visualization. Average EuroSCORE predicted risk for mortality was 27 +/- 12%. RESULTS: Valve positioning was successful in 29 patients and one required early conversion to full sternotomy. Implantation (8 mm x 23 mm and 22 mm x 26 mm valves) was performed on the beating heart during brief periods of rapid ventricular pacing. ECC was applied in 13 patients. Neither coronary artery obstruction nor migration of the prosthesis was observed and all valves displayed good hemodynamic function. Echocardiography revealed minor paravalvular leakage in 14 patients (trace in three, mild in nine and moderate in two). Three patients (10%) died, one on postoperative day (POD) three secondary to preoperative global myocardial failure and two on POD 18 and 86 due to abdominal complications. CONCLUSIONS: Minimally invasive beating heart TAP-AVI is feasible. Initial results are encouraging in view of the high-risk profile of the patients. Long-term studies as well as randomized protocols are required.

Aged↗

PubMed2006

Emergency coronary artery bypass graft surgery for acute coronary syndrome: beating heart versus conventional cardioplegic cardiac arrest strategies.

BACKGROUND: Aim of this study was to compare the outcome of beating heart versus conventional coronary artery bypass graft (CABG) strategies in acute coronary syndromes for emergency indications. METHODS AND RESULTS: 638 consecutive patients with acute coronary syndrome (ACS) receiving emergency CABG surgery via midline sternotomy from January 2000 to September 2005 were evaluated. Propensity score analysis was used to predict the probability of undergoing beating heart (BH) (n=240) versus cardioplegic cardiac arrest (CA) (n=398) strategies. Patients presented with stable hemodynamics (n=531) or in cardiogenic shock (CS) (n=107). Hospital and follow-up outcome was compared by propensity score adjusted multiregression analysis. BH included 116 on-pump and 124 off-pump (OPCAB) procedures. There was a propensity to operate CS patients on the beating heart (multivariate odds ratio [OR], 3.8; P=0.001). Under stable hemodynamics significant predictors for BH selection were logEuroSCORE >20% (OR, 2.05), creatinine >1.8 mg/dL (OR, 4.12), complicated percutaneous coronary intervention (OR, 1.88), ejection fraction <30% (OR, 2.64), whereas left main disease (OR, 0.68), circumflex artery (OR, 0.32), and 3-vessel disease (OR, 0.67) indicated preference for cardioplegic arrest. Time from skin incision to culprit lesion revascularization was significantly reduced in BH patients. BH surgery led to a significant benefit in terms of less drainage loss, less transfusion requirement, less inotropic support, shorter ventilation time, lower stroke rate, and shorter intensive care unit stay. In CS, BH was associated with lower incidence of stroke, inotropic support, acute renal failure, new atrial fibrillation and sternal wound healing complications. In CS patients, hospital mortality rate was reduced when using beating heart strategies (P=0.048). Overall survival, major adverse cerebral and cardiovascular event rate, and repeated revascularization was comparable during a 5-year follow-up. CONCLUSIONS: Beating heart strategies are associated with an improved hospital outcome and comparable long-term results for high-risk patients presenting acute coronary syndrome with or without CS.

Adult↗

PubMed2006

Patient prosthesis mismatch affects short- and long-term outcomes after aortic valve replacement.

OBJECTIVE: The aim of this study was to evaluate the impact of patient prosthesis mismatch (PPM) and additional risk factors on outcome after aortic valve replacement (AVR). METHODS: Four thousand one hundred and thirty-one patients who were operated between May 1996 and April 2004 were evaluated. One thousand eight hundred and fifty-six patients received bileaflet mechanical AVR and 2275 stented xenograft AVR. PPM was defined as severe if manufacturers effective orifice area (EOA) divided by body surface area (BSA) was <0.65 cm(2)/m(2) and as moderate in the range of 0.65-0.85 cm(2)/m(2). PPM, age, gender, EOA index, emergency indication for surgery (within 24h), EuroSCORE as well as requirement for additional procedures were tested. Univariate (Fisher's exact test) and multivariate logistic regression analysis as well as survival analysis (Kaplan-Meier) were performed. RESULTS: Severe PPM was present in 97 (2.4%) and moderate PPM in 1103 (26.7%) patients. PPM occurs more frequently with xenograft AVR. In-hospital mortality was 5.2% for severe, 10.6% for moderate and 6.9% with no PPM (p=0.018, OR 1.4). Moderate PPM was independently predictive for short- and long-term mortality. Further analysis revealed patient age >70 years (n=1589, p=0.002, OR 1.85), emergency indication (n=374, p<0.001, OR 4.4), EuroSCORE >10 (n=494, p<0.001, OR 4.7) and additional cardiac procedures (n=2049, p<0.001, OR 2.0) as predictors for adverse outcome after AVR. CONCLUSION: Severe PPM is rare; moderate PPM is present in a quarter of patients. PPM has a significant impact on short- and long-term mortality after AVR.

Aged↗

PubMed2006

[Off-pump coronary artery bypass grafting. State of the art 2006 and results in comparison with conventional coronary artery bypass strategies].

Adverse clinical consequences associated with conventional coronary artery bypass surgery (CCAB) have largely been attributed to cardiopulmonary bypass circuit (CPB), hypothermic cardiac arrest, aortic cannulation, and cross-clamping. Consequently, there has been a growing interest in safer alternatives to CCAB including off-pump beating-heart bypass surgery (OPCAB). Initial concerns regarding completeness of revascularization at the lateral wall were addressed by using modern stabilizers and heart positioning devices. First studies tended to be nonrandomized clinical reports rather than controlled clinical trials with the potential risk of unbalanced baseline characteristics leading to biases in favor of OPCAB. Since these early reports, several randomized trials including mixed-risk patient populations have been completed. Most of them failed to reveal superiority of OPCAB concerning mortality and major perioperative morbidity due to statistically underpowered design to detect clinically important but infrequent adverse outcome events. Likewise, in most of the recently published meta-analyses of randomized trials no difference in early mortality, myocardial infarction or stroke rate was found, but OPCAB was superior regarding blood loss, transfusion requirement, rethoracotomy, ventilation time, ICU (intensive care unit) and hospital stay and resource utilization as illustrated in Table 1. Most of the large observational studies comparing OPCAB and CCAB strategies demonstrated a benefit of OPCAB concerning early mortality, myocardial infarction and stroke rate as summarized in Table 2. However, in few published follow-up studies no significant differences concerning recurrence of angina, reintervention rate und late mortality were found. The decision between OPCAB and CCAB has to weigh several factors, including the likely risks and benefits of the two approaches for the particular patient, the experience of the surgeon, the complexity of the coronary disease, and the required coronary revascularization.

Coronary Artery Bypass↗

PubMed2006

Six-month angiographic follow-up of the PAS-Port II clinical trial.

BACKGROUND: The PAS-Port device (Cardica, Redwood City, CA) allows the rapid deployment of a clampless proximal anastomosis between a vein graft and the aorta. METHODS: Fifty-four patients awaiting elective coronary artery bypass graft surgery were enrolled. Outcome variables were intraoperative device performance, early and 6- month angiographic graft patency, and 12-month clinical follow-up. RESULTS: Sixty-three PAS-Port devices were deployed in 54 patients. Two deployments were unsuccessful. There were no reoperations for bleeding. Two patients died of causes unrelated to the device. Patency evaluation at discharge was performed by angiogram on 49 implants and computed tomography in 2 implants (86% follow-up). At discharge, all evaluated grafts were patent (100%) and rated Fitzgibbon A. At 6-month follow-up, there was no additional mortality; 47 implants (88% follow-up) were evaluated by angiography (Fitzgibbon O [n = 1], Fitzgibbon B [n = 1], and Fitzgibbon A [n = 45]) and 5 by computed tomography. All grafts but 1 were patent (98.1%). At 12 months, 2 additional patients died of causes unrelated to the PAS-Port implant. Forty-six of 50 alive patients (95.8%) were followed up without any reports of device-related major adverse cardiac events. CONCLUSIONS: Discharge (100%) and 6-month patency (98%) are excellent; patency and 12 months' clinical follow-up compares favorably with data from historical hand-sewn controls. The PAS-Port system safely allows the clampless creation of a proximal anastomosis.

Aged↗

PubMed2006

Invited commentary.

Explore the source record for details and available documents.

Coronary Artery Bypass, Off-Pump↗

PubMed2006

Minimally invasive surgery for valve disease.

Heart valve surgery evolved since the early 1960s toward routine clinical application with good patient outcome. Different surgical techniques and valve prostheses have been developed. Thus standard procedures were continuously established. The different surgical procedures have now gained widespread clinical acceptance with good patient outcomes. Aortic valve stenosis and mitral valve incompetence are the most frequently acquired heart valve lesions in the western communities. Usually such lesions reach clinical significance in patients during their fifth to eighth decade of life. Standard surgical techniques of aortic valve repair and mitral valve replacement or repair result in persistent cure of the disease. Surgical access was gained using conventional lateral thoracotomies in the early days and later on using median sternotomy. Minimally invasive techniques, mostly by a partial sternotomy for the aortic and a lateral minithoracotomy for the mitral position, have been increasingly applied to improve patient outcome since the mid 1990s. At specialized centers these techniques have evolved as clinical standard allowing all different valve procedures to be safely performed. Patient recovery is fast leading to a significant improvement in the individual's quality of life. Minimally invasive valve surgery can be considered the standard approach and will reach more widespread clinical application.

Aortic Valve Stenosis↗

PubMed2006

Modeling of temperature mapping for quantitative dynamic infrared coronary angiography for intraoperative graft patency control.

OBJECTIVES: Intraoperative application of thermal coronary angiography based on dynamic infrared imaging leads to useful qualitative information concerning coronary artery bypass graft flow and anatomy. Additional quantitative flow estimation is desirable to detect graft failures. The aim of this study was to develop a heat-transfer model for quantitative flow estimation in an experimental setup. The first clinical results in coronary artery bypass grafting are reported. METHODS: Dynamic infrared imaging was applied in pig hearts to collect video data of the rewarming process of the left anterior descending artery supplied by antegrade perfusion. For mathematic description, we used the dynamic enthalpy balance for open systems, and a Laplace transformation was carried out. Therefore the time constant tau was calculated by performing a nonlinear fit procedure on the averaged dynamic temperature curves recorded over a left anterior descending artery segment. Subsequently, left internal thoracic artery-left anterior descending artery bypass graft flow was assessed intraoperatively. Effective left anterior descending artery flow was determined by using a transit-time flowmeter. RESULTS: Tau is a system constant and changes depending on the flow and the system capacity. Assuming system capacity to be constant, tau only depends on the flow. It follows from the differential equation that there is a potential relation between tau and the flow. An excellent comparison (R2 = 0.968, P <.005) was demonstrated. By using the algorithms, quantitative flow estimation in pig hearts was possible. For clinical application, the formulas were applied to intraoperatively derived dynamic temperature curves with a good comparison to the actual left internal thoracic artery-left anterior descending artery flow. CONCLUSION: The developed heat-transfer model allows for precise measurement of graft flow by using dynamic infrared imaging and can be applied for noninvasive graft flow estimation in beating-heart surgery.

Animals↗

PubMed2006

Surgical PACS for the digital operating room. Systems engineering and specification of user requirements.

For better integration of surgical assist systems into the operating room, a common communication and processing plattform that is based on the users needs is needed. The development of such a system, a Surgical Picture Aquisition and Communication System (S-PACS), according the systems engineering cycle is oulined in this paper. The first two steps (concept and specification) for the engineering of the S-PACS are discussed.A method for the systematic integration of the users needs', the Quality Function Deployment (QFD), is presented. The properties of QFD for the underlying problem and first results are discussed. Finally, this leads to a first definition of an S-PACS system.

Computer Simulation↗

PubMed2006

Reverse remodeling of cardiac collagen protein expression after surgical therapy for experimental aortic stenosis.

BACKGROUND AND AIM OF THE STUDY: Reversal of myocardial collagen gene expression was examined in parallel to left ventricular reverse remodeling after surgical correction of experimental aortic stenosis. METHODS: A standard growing sheep model (age at baseline 6-8 months) was used. Measurements were performed at baseline (point A) when inducing left ventricular hypertrophy (LVH) through supracoronary banding, at 8.3 +/- 1.0 months later at surgical correction (point B), and after another 10.1 +/- 2.0 months during final examinations (point C). Gene expression for collagen I and III was also studied. RESULTS: Left ventricular function was stable throughout the study. The left ventricular mass index (LVMI) was 82 +/- 21 g/m2 at point A, 150 +/- 33 g/m2 at B, and 78 +/- 18 g/m2 at C (p <0.01). Myocardial fiber diameter was 11.3 +/- 0.8, 15.9 +/- 1.2 and 11.4 +/- 1 microm at points A, B and C, respectively (p <0.01). Protein expression for collagen I was 0.71 +/- 0.2 (at A), 1.13 +/- 0.3 (at B) and 0.85 +/- 0.4 (at C) (p <0.01), while that for collagen III was 0.72 +/- 0.4 (at A), 1.26 +/- 0.8 (at B) and 0.83 +/- 0.3 (at C) (p <0.01). There was a significant correlation between changes in LVMI and myocardial collagen expression. CONCLUSION: Complete reverse remodeling with regression of LVH and myocardial collagen protein expression can be anticipated after surgical correction of experimental aortic stenosis.

Animals↗

PubMed2005

Comparison of bare-metal stenting with minimally invasive bypass surgery for stenosis of the left anterior descending coronary artery: a 5-year follow-up.

BACKGROUND: Randomized trials comparing stenting with minimally invasive direct coronary artery bypass surgery in patients with isolated proximal left anterior descending lesions have shown a significantly higher reintervention rate for stenting and similar results for mortality and reinfarction at short-term follow-up. Long-term follow-up data are sparse. METHODS AND RESULTS: Patients with isolated proximal left anterior descending stenosis were randomized to either surgery (n=110) or bare-metal stenting (n=110). At 5 years, follow-up data were obtained with respect to the primary end point of death, reinfarction, or repeated target vessel revascularization. Clinical symptoms were assessed by the Canadian Cardiovascular Society (CCS) classification. Follow-up information was completed for 216 patients (98.2%), and mean follow-up was 5.6+/-1.2 years. With respect to mortality (surgery, 12%; stenting, 10%; P=0.54) and reinfarctions (surgery, 7%; stenting, 5%; P=0.46), there were no differences between treatment strategies. The need for repeated target vessel revascularization was significantly higher after stenting (32%) compared with surgery (10%; P<0.001). Clinical symptoms improved significantly in both treatment groups compared with baseline; however, there was a favorable trend for surgery (stenting: CCS, 2.6+/-0.9 to 0.5+/-0.8, P<0.001; surgery: CCS, 2.6+/-0.9 to 0.3+/-0.6, P<0.001; P=0.05, stenting versus surgery). CONCLUSIONS: At the 5-year follow-up, minimally invasive bypass surgery and bare-metal stenting showed similar results for the end points of mortality and reinfarctions. However, the reintervention rate is higher after stenting, and the relief in clinical symptoms is slightly better after surgery.

Aged↗

PubMed2005

The Cardica C-Port System: clinical and angiographic evaluation of a new device for automated, compliant distal anastomoses in coronary artery bypass grafting surgery--a multicenter prospective clinical trial.

OBJECTIVES: The C-Port System (Cardica, Inc, Redwood City, Calif) integrates in one tool all functions necessary to enable rapid automated distal coronary anastomoses. The goal of this prospective, nonrandomized, and multicenter study is to determine the safety and efficacy of this novel anastomotic system. METHODS: Five centers enrolled 133 patients awaiting elective coronary artery bypass grafting surgery. Outcome variables were intraoperative device performance, incidence of device-related adverse events, predischarge and 6-month angiographic graft patency, and 12-month clinical outcome. Independent core laboratories performed qualitative and quantitative angiographic and computed tomographic assessments. RESULTS: The C-Port was used to perform a vein-to-coronary anastomosis in 130 patients. Intraoperative conversion to a hand-sewn anastomosis was necessary in 11 patients because of inadequate target site preparation, inappropriate target vessel selection, or both. Inadequate blood flow related to poor runoff required conversion in 3 additional patients. Three patients died before discharge of causes unrelated to the device. At discharge, 113 patients had a C-Port implant in place, and 104 C-Port anastomoses were studied by means of angiography, resulting in 100 FitzGibbon A, 3 FitzGibbon B, and 1 FitzGibbon 0 classifications. At 6 months, one additional patient died of a device-unrelated cause, and 98 patients were evaluated by means of angiography (n = 89). Overall patency (FitzGibbon A) was 92.1%. Three C-Port anastomoses were rated FitzGibbon B, and 4 were rated FitzGibbon 0. At 12 months, 107 (98.2%) of 109 alive patients were followed up, without any reports of device-related major adverse cardiac events. CONCLUSIONS: The C-Port System allows for a rapid, reliable, and compliant distal anastomosis and yields favorable 6-month angiographic and 12-month clinical results when compared with published studies.

Aged↗

PubMed2005

Beating heart off-pump myocardial revascularization in an infant.

A 6-week-old patient weighing 4 kg was admitted for surgical correction of anomalous left coronary artery from the pulmonary artery. Reimplantation of the coronary artery with cardiopulmonary bypass was impossible because the patient also had hereditary spherocytosis, which put him at risk for hemolytic anemia. Thus, closure of the left main stem and left internal mammary artery-left anterior descending coronary artery bypass grafting were performed successfully with the heart beating.

Coronary Artery Bypass, Off-Pump↗

PubMed2005

Impact of off-pump coronary bypass grafting on the prevalence of adverse perioperative outcome in women undergoing coronary artery bypass grafting surgery.

BACKGROUND: Female gender has been associated with a high prevalence of perioperative morbidity and mortality in coronary artery bypass grafting surgery (CABG). We attempted to determine a potential benefit of off-pump CABG as compared with on-pump CABG (OPCAB) with regard to perioperative outcome in female patients. METHODS: Data were prospectively gathered on 2,182 consecutive female patients undergoing CABG either with or without cardiopulmonary bypass from 1996 to 2001. The associations between OPCAB surgery in addition with 22 further preoperative patient-related or treatment-related variables and 26 perioperative outcome variables were assessed with multivariable logistic regression analysis. RESULTS: One hundred fifty-two (7.0%) female patients underwent OPCAB surgery during the study period. Women undergoing OPCAB had higher ejection fractions and received fewer coronary artery bypass grafts than CABG patients. Surgery using OPCAB was associated with shorter hospital stays, less bleeding, less transfusion requirements, and lower mortality than CABG. Furthermore, OPCAB surgery was independently associated with a lower prevalence of high perioperative transfusion requirement, postoperative respiratory insufficiency, postoperative renal insufficiency, and dialysis. Prevalence of postoperative blood loss of at least 500 mL was significantly higher after OPCAB surgery. CONCLUSIONS: OPCAB in female patients undergoing coronary artery bypass surgery is safe and seems to be beneficial with regard to perioperative outcome as compared with conventional on-pump CABG. For that reason, off-pump surgery may be an effective method of lowering morbidity and mortality in these relatively high-risk patients.

Aged↗

PubMed2005

Clinical experience with stentless mitral valve replacement.

BACKGROUND: Our aim is to describe the clinical experience with stentless mitral valve (SMV) replacement with special focus on the functionality of the SMV. METHODS: Fifty-two patients (68 +/- 8.5 years old; 36 female) have been prospectively evaluated since August 1997. The chordally supported SMV (Quattro) was implanted for mitral stenosis (n = 26), severe incompetence (n = 17), or mixed lesion (n = 9). Preoperative New York Heart Association class was 3.1 +/- 0.6. Twenty patients received additional intraoperative ablation therapy. Mean follow-up is 37.3 +/- 18.7 months (range, 1 to 65). RESULTS: Surgery was performed using conventional sternotomy (33) or anterolateral minithoracotomy (19). Atrial rhythm was reestablished in 17 of 20 patients. Six patients operated on early in this series required reoperation, 2 for paravalvular leakage, 2 for functional stenosis, 1 with pannus formation due to underlying rheumatoid disease, and 1 for papillary flap rupture after 5.1 years. Mortality was 1 perioperative (1.9%, nonvalve related) and 1 after reoperation due to multiorgan failure. During late follow-up (30 +/- 7 months postoperatively) 5 patients died of noncardiac causes. Regular echocardiographic control revealed good SMV function (maximum transmitral blood flow velocity 1.7 +/- 0.2 m/s; mean transmitral pressure gradient 3.9 +/- 1.2 mm Hg) and well-preserved ejection fraction postoperatively as well as at most recent follow-up. CONCLUSIONS: The clinical experience after 5.5 years of SMV implantation is promising. Preservation of annuloventricular continuity is advantageous. However, long-term durability remains to be proved.

Aged↗

PubMed2005

Cardio navigation: planning, simulation, and augmented reality in robotic assisted endoscopic bypass grafting.

BACKGROUND: The aim of this study is to optimize the set-up and port placement in robotic surgery and enhance intraoperative orientation by video overlay of the angiographic coronary tree. METHODS: In three mongrel dogs and two sheep an electrocardiogram-triggered computed tomographic scan and coronary angiography were performed after placing cutaneous fiducials. The regions of interest (ie, heart, ribs, coronaries, internal thoracic artery) were segmented semiautomatically to create a virtual model of the animal. In this model the target regions of the total endoscopic bypass procedure along the internal thoracic artery and anastomotic area were defined. Algorithms for weighing visibility, dexterity, and collision avoidance were calculated after defining nonadmissible areas using a virtual model of the manipulator. Intraoperatively, registration of the animal and the telemanipulator was performed using encoder data of the telemanipulator by pointing to the fiducials. After pericardiotomy, the reconstructed coronary tree was projected into the videoscopic image using a semiautomatic alignment procedure. In dogs, the total endoscopic bypass procedure was completed on the beating heart. The first human case applying preoperative planning, intraoperative registration, and augmented reality was subsequently performed. RESULTS: The rigid transformation linked the patient's preoperative frame and the robot coordinate frame with a root mean square error of 9 to 15 mm. The predicted port placement derived from the model initially varied from the one chosen due to an incomplete formulation of the weighing procedure. After only a few iterations, the algorithm became robust and predicted a collision free triangle. Video overlay of the angiographic coronary tree into the videoscopic image was feasible. CONCLUSIONS: Surgical planning and augmented reality are likely to enhance robotic surgery in the future. A more complete understanding of the surgical decision process is required to better formalize the planning algorithms.

Algorithms↗