Development of robotic enhanced endoscopic surgery for the treatment of coronary artery disease.

BACKGROUND: The introduction of robotic enhanced surgery demanded stepwise development of performed procedures on the basis of growing experience of the operating team. METHODS AND RESULTS: Between May 1999 and January 2001, this new wrist-enhanced instrumentation was used in 201 patients (156 men and 45 women, median age 64+/-10.5 years, left ventricular ejection fraction 68+/-12.4%). During the development of robotic enhanced CABG, the patients were divided into 3 groups. Group A (n=156) consisted of patients in whom the robotic system was used to harvesting the left or right internal mammary artery, or both, whereas the anastomoses were performed directly through a small chest incision. In group B (n=37), the harvest of the internal mammary arteries and the coronary anastomoses were performed totally endoscopically. In a third early group C, patient (n=8) were treated with robotic enhanced CABG via a median sternotomy already preoperatively planned, whereas gradual step-by-step application of robotic instrumentation and its feasibility were assessed. The survival rate was 99.4%. One patient (0.6%) died due to pneumonia on postoperative day 16. Conversion rate to median sternotomy was 5%. The left and right internal mammary artery conduits could be successfully harvested in 98% and 100%, respectively. The time of dissection of the left internal mammary artery could be significantly reduced alone by increasing experience. All patients were discharged from the hospital after a mean of 7 days. In 9 patients (4.5%), bleeding required reexploration. CONCLUSIONS: The introduction of this new surgical tool enables the development of new endoscopic procedures. Our results gained during the development of robotic enhanced CABG motivate us to establish a set standard for the totally endoscopic treatment of patients with 1-vessel coronary artery disease.

Closed chest bilateral mammary artery grafting in double-vessel coronary artery disease.

A clinical case of a closed chest double-vessel total endoscopic coronary artery bypass procedure was performed using a wrist-enhanced, three-dimensional-based robotic system. A patient suffering from lesions of the left coronary artery system was effectively treated surgically without median sternotomy or minithoracotomy. This encourages optimism for introducing closed chest endoscopic bypass operations into the surgical routine for patients suffering from double-vessel coronary artery disease.

Robotic-enhanced arterial revascularization for multivessel coronary artery disease.

BACKGROUND: A tendency to reduce operative trauma is determining the evolution of cardiac surgical techniques lately. The introduction of robotic-enhanced endoscopic systems enables surgeons to perform arterial revascularization for multivessel disease without sternotomy. METHODS: From May 1999,17 (4 women, 13 men; median age 63+/-7.4 years) patients with multivessel coronary artery disease were treated surgically using arterial revascularization by means of bilateral internal mammary arteries. Both arteries were harvested endoscopically using the da Vinci system (Intuitive Surgical, Mountain View, CA). These vessels were anastomosed using the "Dresden technique." RESULTS: Survival was 100%. Mean duration of the operation was 255+/-40.4 minutes. Bilateral internal mammary artery harvesting took 88.5+/-15.9 minutes; cross-clamp time was 36+/-8.7 minutes. An average of 2.06 anastomoses were performed per operation. Postoperatively, patients remained in the intensive care unit for 21+/-13 hours. One patient (5.8%) needed reexploration due to bleeding. CONCLUSIONS: The robotic surgical system introduces a new treatment of coronary artery disease to surgical practice, and enables arterial revascularization with distinctly reduced surgical trauma.

Wrist-enhanced instrumentation: moving toward totally endoscopic coronary artery bypass grafting.

BACKGROUND: With the introduction of the da Vinci robotic surgical system (Intuitive Surgical, Mountain View, CA) into minimally invasive cardiac operations the outlook for performing coronary artery bypass operations "closed chest" became a reality. METHODS: Between May 1999 and December 1999 this new wrist-enhanced instrumentation was used in 61 patients. Six patients suffering from single-vessel coronary artery disease and one female patient with double-vessel disease underwent totally endoscopic coronary artery bypass. Thirty-seven patients with single-vessel disease underwent a minimally invasive direct coronary artery bypass procedure. Seventeen patients with double-vessel disease were treated using the robotic-enhanced Dresden technique. RESULTS: Perioperative survival was 100%. In all patients the internal mammary arteries were safely harvested endoscopically and had excellent quality. In both totally endoscopic coronary artery bypass groups all patients were operated on through three stab incisions. CONCLUSIONS: Our preliminary experience with this new surgical technique using robotic-enhanced minimally invasive methods for coronary artery disease promotes optimism regarding further development of these procedures and application in patients with coronary artery disease.

Early experience with a quadrileaflet stentless mitral valve.

BACKGROUND: Presently no ideal prosthesis for mitral valve replacement exists. The quadrileaflet mitral valve (SJM-Quattro-MV; St. Jude Medical, Inc, St. Paul, MN) is a chordally supported stentless bioprosthesis. Due to its specific geometry it seems to be particularly suited for mitral valve replacement. METHODS: From March 1999 to October 2000, 12 patients (ages 71+/-2 years) received the SJM-Quattro-MV. Six patients suffered from valvular stenosis and 6 patients from incompetence. Preoperatively, all patients were in New York Heart Association functional class III, with left ventricular ejection fraction amounts of 54%+/-17%. RESULTS: Eleven patients received a medium size SJM-Quattro-MV and one patient received a large size SJM-Quattro-MV. Cross-clamp time was 99.8+/-4.9 minutes. Additional procedures were coronary artery bypass grafting (n = 3) and left atrial microwave ablation (n = 2). Postoperative mortality (n = 1) was procedure related. At follow-up of 11.6+/-5.4 months, all patients were well, the transvalvular pressure gradient was 5.0+/-1.4 mm Hg, and the effective orifice area 2.7+/-0.2 cm2. CONCLUSIONS: Our preliminary experiences with the SJM-Quattro-MV presented good clinical results and promoted an optimistic way of thinking about the further development of these valve prostheses.

Minimally invasive surgical treatment of coronary artery multivessel disease.

BACKGROUND: If coronary artery multivessel disease is the target of a minimally invasive procedure, either median sternotomy or cardiopulmonary bypass can be avoided. METHODS: We used an alternate technique instead of minithoracotomy and cardiopulmonary bypass to treat 102 patients (82 men, 20 women; age range, 39 to 82 years; median, 61.0 +/- 8.9 years) for coronary artery single-vessel, double-vessel, or multivessel disease between November 1996 and January 1998. Twenty-nine patients (22 men, 7 women; age range, 46 to 78 years; median, 69.0 +/- 8.4 years), who were in a high-risk group for the development of perioperative complications because of the use of cardiopulmonary bypass, received median sternotomy and a beating heart procedure using the Octopus stabilizing technique. The left anterior descending coronary artery was the target vessel in all patients except for 1, in whom the left internal mammary artery was used. RESULTS: There was no intraoperative death in either series. In the beating heart group (Octopus) 2 patients died on postoperative day 31 and 35, respectively, of postoperative pneumonia. CONCLUSIONS: Both techniques present safe alternative procedures to conventional coronary artery bypass grafting in patients with coronary artery multivessel disease.

The Dresden approach for complete multivessel revascularization.

BACKGROUND: In a prospective clinical trial, a group of patients receiving less invasive surgical procedure, including minithoracotomy in combination with cardiopulmonary bypass (group 1), was compared to a group of patients receiving conventional bypass surgery (group 2) for the treatment of coronary artery disease. METHODS: Group 1 included 85 patients (71 men, 14 women, aged 39 to 82 years, median 61.1 +/- 9.0 years); group 2 included 53 patients (38 men, 15 women, aged 51 to 79 years, median 62.0 +/- 6.1 years). RESULTS: There were no perioperative deaths in the whole series of patients. Time of operation was 256 +/- 43 minutes in group 1 and 150.0 +/- 53.6 minutes in group 2. Hospitalization was 6.0 +/- 1.4 days and intensive care unit stay 1 day for both groups. Back pain assessment on postoperative day 3 showed less pain in group 1. Three-month follow-up revealed ischemia in stress electrocardiogram in 2 patients (2.5%) in group 1 and in 2 patients (4.1%) in group 2. Coronary angiograms confirmed the stress-electrocardiogram findings. CONCLUSIONS: Surgical results are equal for both techniques. Even though time of operation is longer in patients receiving less invasive procedures, intensive care unit stay and hospital stays are the same length. Early postoperative back pain is less in group 1 and combined with faster convalescence.

The application of the Octopus stabilizing system for the treatment of high risk patients with coronary artery disease.

OBJECTIVES: If coronary disease is the target of a minimally invasive procedure, median sternotomy or cardiopulmonary bypass or both can be avoided. Similar to the development in other fields of surgery, minimally invasive surgical techniques are gaining increased acceptance in the field of cardiothoracic surgery. Our experience with an off pump coronary artery bypass (OPCAB) technique in a special patients group with serious risk factors for the application of cardiopulmonary bypass has been analyzed. METHODS: Between March 1996 and January 1999, 88 patients (64 male, 24 female) with impaired left ventricular function, or other high risk factors jeopardizing the use of cardiopulmonary bypass, such as impaired renal or lung function or heavily calcified aorta, received a beating heart procedure using the Medtronic Octopus stabilizing system. RESULTS: All patients survived the actual operation, however, two multimorbide patients died of pneumonia on postoperative day 31 and postoperative day 35. CONCLUSIONS: Patients with single-vessel to multivessel disease and serious risk factors for cardiopulmonary bypass can be safely treated by OPCAB surgery. At our institution this technique presents the procedure of choice in this particular patients group.

Coronary artery bypass grafting via median sternotomy or lateral minithoracotomy.

OBJECTIVES: In order to evaluate the benefit provided through less invasive surgical techniques for the treatment of multivessel coronary artery disease, a prospective clinical trial was started. METHODS: Group 1 included 53 patients (38 males, 15 females, age 51-79 years, mean 62.8 +/- 6.1 years) receiving conventional bypass surgery, group 2 included 69 patients (59 male, 10 female, age 43-82 years, mean 61.9 +/- 8.6 years) receiving less invasive surgical procedure including minithoracotomy in combination with cardiopulmonary bypass. RESULTS: No perioperative death occurred in the whole series of patients. Time of operation was 267 +/- 61 min in group 2 and 162.9 +/- 53.6 min in group 1. Intensive Care Unit stay was 1 day for both groups and Hospitalization 6.9 +/- 6.0 for group 1 and 7.5 +/- 2.6 days for group 2. Perioperative bleeding was less in group 2 (P > 0.01). Back and chest pain assessment on postoperative day 3 showed less pain in group 2 (P < 0.05). Three-month follow-up revealed ischemia in stress electrocardiogram in two patients (3.8%) in group 1 and in 2 patients (2.9%) in group 2. Coronary angiograms confirmed the stress ECG findings. There was one (1.4%) redo operation in group 2 and two (3.8%) in group 1. CONCLUSIONS: Both techniques are equal efficient. Even though time of operation is longer in patients receiving less invasive procedure, intensive care unit stay and hospitalization is exactly as long. Patients receiving minimally invasive surgery bleed less and have less pain early postoperatively.

Experiences with a minimally invasive surgical technique for the treatment of coronary artery multivessel disease in 100 patients.

OBJECTIVE: The treatment of coronary single vessel disease under minimally invasive surgical conditions was followed by the treatment of coronary multivessel disease using a new technique. METHODS: Using this technique 100 patients (80 male, 20 female, median age 61.0+/-8.9 years, ranged from 39 to 82 years) with coronary single vessel disease, double vessel disease or multivessel disease were treated between November 1996 and December 1997. Via a small (6-9 cm) left lateral chest incision in the second or third intercostal space, the left internal thoracic mammary artery (LIMA) was harvested and access to the central portion of the heart including the ascending aorta was obtained. In parallel, saphenous vein segments were harvested. Arterial cannulation was instituted via the ascending aorta, thus avoiding retrograde flow. In all patients except three the LIMA was used for the left anterior descending artery (LAD). In addition vein grafts were used for revascularization of the other coronary arteries. All cardiac anastomoses were performed during cardioplegic arrest after external aortic cross clamping and antegrade application of cardioplegia. RESULTS: No death or intraoperative complications were observed in this series. The median hospital stay was 6.0+/-1.4 days (median+/-SEM). Postoperative complications were reexplored for bleeding (n = 1), delayed wound healing (n = 2), wound infections (n = 4), lymphatic fistulas (n = 4), and a chest wall hernia (n = 1). CONCLUSIONS: This minimally invasive surgical technique presents a safe alternative to conventional coronary artery surgery avoiding sternotomy related complications and decreasing hospital stay and morbidity.

Technique of closed chest coronary artery surgery on the beating heart.

OBJECTIVE: The application of an endoscopic stabilizer (Intuitive Surgical, Mountain View, CA, USA) enables closed chest off-pump coronary artery bypass via a four-point stab incision avoiding sternotomy and minithoracotomy. METHODS: Between May 1999 and January 2001 we operated upon a total of 37 patients (five female, 32 male, median age 62+/-9 years) suffering from coronary artery disease using totally endoscopic coronary artery bypass (TECAB), whereas an initial series of eight TECAB patients was operated upon using an endovascular bypass system (Heartport). The da Vinci surgical system was used in order to perform left internal mammary artery (LIMA) or right internal mammary artery (RIMA) harvesting and anastomoses on a beating heart in 29 patients (four female, 25 male, median age 64+/-9.8 years). Altogether 26 patients suffering from single-vessel coronary artery disease (SVCAD) were revascularized applying LIMA to the left anterior descending artery (LAD) and three patients with two diseased coronary vessels received bilateral internal mammary artery grafting (BIMA), respectively. RESULTS: In this series we had a 100% survival rate. Conversion rate to a median sternotomy was 3.4%. Patients were operated upon via four 1-cm chest incisions using the da Vinci robot for LIMA or BIMA harvesting and for performance of anastomoses on the beating heart. In the overall series of 56 patients intended to be treated by TECAB, 19 (33.9%) were converted to a minimally invasive direct coronary artery bypass procedure. CONCLUSION: This new robotic-enhanced surgical technique promotes an optimistic way of thinking about the further development of this procedure and its application in patients suffering from single-vessel CAD.

Physical overdistension converts ventricular cardiomyocytes to acquire endocrine property and regulate ventricular atrial natriuretic peptide production.

Atrial natriuretic peptide (ANP) is present in adult atria but at very low concentrations in normal adult mammalian ventricles. In the atria, the production of ANP is regulated by physical distension of the atrial wall. The same phenomenon was investigated in the ventricles of rats and men. Cardiac tissues from human ventricular aneurysm (n = 5), spontaneously hypertensive rats (n = 30), and rats that had overloaded left ventricles induced by surgery (n = 84) were studied with the methods of light microscopic immunocytochemistry, electron microscopic immunogold staining, and RNA-RNA tissue in situ hybridization. It was found that the levels of ANP gene expression, ANP immunoreactivity, and ANP-containing specific granules in the overburdened ventricles were elevated and their degrees of fluctuation were directly proportional to the force of physical distension applied to the ventricular cardiomyocytes. In rats, ANP mRNA and ANP immunoreactivity returned to the control level seven days after the ventricular overload was surgically released. The changes of ANP and its mRNA in the ventricles were related more closely to the changes of intraventricular pressure than to cardiocytic hypertrophy. In addition, ANP immunoreactivity was demonstrated in Purkinje cells and periarteriolar cardiomyocytes in the ventricles of normotensive rats. In conclusion, physical overstretch of the ventricle wall is likely to be the triggering factor affecting ventricular cardiomyocytes to acquire endocrine property, and also to regulate the production of ventricular ANP, thereby contributing to the control of the blood volume and the blood pressure.

Physical manipulation of subcutaneously implanted cardiac muscle in rat increased plasma atrial natriuretic peptide concentration.

UNLABELLED: To examine the effects of physical stretch on cardiac muscle endocrine activity, the authors transplanted whole neonatal hearts subcutaneously into the back and the ears of the correspondent mother (n = 9). Seven days later, physical manipulation was applied on the implanted heart by stretching the skin and the subcutaneous tissue encasing the implanted cardiac muscle, for a period of five to ten minutes. Such manipulation was repeated approximately every seven days postoperatively for a total of two to four times for each rat. The plasma atrial natriuretic peptide (ANP) levels were measured by radioimmunoassay prior to and immediately following manipulation. Postmanipulation plasma ANP levels were found to increase from the premanipulation levels. At two weeks postimplant, the average increase was 290% with the highest single-specimen increase being nearly twelvefold. The increases observed at two and three weeks following implantation had Signed Rank Test p values of 0.015 and 0.042 respectively. The viability of the implanted hearts was confirmed by cell culture. Light microscopic immunocytochemistry detected ANP immunoreactivity in the implanted cardiocytes. The elevated plasma ANP concentration induced by the manipulation appeared to be correlated with the functional status of the implanted cardiocytes. IN CONCLUSION: (1) Subcutaneously transplanted neonatal myocardiocytes survived for at least three to four weeks while retaining the ability to produce ANP. (2) Physical manipulation of implanted heart induced ANP release. Therefore, cardiac ANP production and release is indeed stimulated by physical stretching.

Effect of polyoxyethylene glycols (PEG) on properties of the matrix model of transdermal therapeutic system (TTS) with testosterone.

Polyoxyethylene glycols (PEG) are nontoxic substances, which ones do not irritate the skin, therefore can be used as pharmaceutical excipients to differentiate the properties of various matrices. The effect of variable content and molecular mass of PEG in cellulose acetate matrices on the testosterone solubility, the rate of water sorption and the release rate of testosterone from the matrix model of TTS was studied. It may be concluded that the testosterone solubility in matrices, the rate of water sorption by systems and the pharmaceutical availability of drug can be regulated on a relatively wide scale independently of molecular mass by the amounts of PEGs incorporated into matrices. It was found that in all cases of triphase matrices the liberation process of terosterone was well correlated with Higuchi's equation. The rate of water sorption by PEG and matrices may be described by the equation Q = k square root of t.

Gastrointestinal therapeutic system delivering of a water insoluble drug: isosorbide dinitrate (ISDN).

An oral therapeutic system can only be effective for soluble drugs. If no suitable salt of a drug can be found, then an osmotic agent such as sodium chloride or mannitol has to be used in a modified two-chamber system, or the osmotic dispenser with collapsible supply container. A one-chamber gastrointestinal therapeutic system (GTS) is proposed which is capable of delivering insoluble drug at a relatively constant rate. The unit consists of a tablet containing the insoluble drug and the soluble carrier, surrounded by a rate-controlling membrane with a delivery orifice. If the unit is in contact with fluid, water will pass constantly through the membrane into the tablet, dissolve the carrier which will be pumping out the insoluble drug through the delivery orifice. The effect was studied of variable content and weight of the tablet, size of the delivery orifice and thickness of the membrane on the rate of insoluble drug release from the GTS.

[Cardiogenic shock. Surgical reperfusion and myocardial revascularization]. / Wstrzas kardiogenny. Chirurgiczna reperfuzja i rewaskularyzacja miesnia sercowego.

Emergency coronary bypass for cardiogenic shock has been associated with a high operative mortality. From February 1986 through October 1989, 40 patients with acute myocardial infarction were operated. Ten pts (25%) were in shock despite intensive treatment (intra-aortic balloon pump in 4, catecholamines in 10). Seven pts. required cardiopulmonary resuscitation before operations. After operations 66% of the patients required catecholamine support and 60% were treated with intra-aortic balloon pump. There were three (30%) hospital deaths (one in the operating room due to acute cardiac failure). Follow-up (100%),(mean 26 months) revealed one late death--39 months after operations. In functional class I were 2 patients, II--one, and III--two pts. One pt is in group IV (transplant candidate). Myocardial infarction complicated by cardiogenic shock can produce a mortality rate in excess of 85%. Contemporary medical management has had little effect on mortality, hence effective surgical therapy has evolved for this lesion.

[Miniature assistance module for robot-assisted heart surgery]. / Miniatur-Assistenzmodule für die robotergestützte Herzchirurgie.

During the robotic enhanced minimally invasive cardiac surgery the approach to and the space for handling instruments in the operating field are usually reduced, compared to the conventional surgery. Additional well knewn problems are the restricted capability available for accessories into and out of the closed chest and the limited assistance during the cardiac procedure. This paper is presenting two solutions of Miniature Modules for supporting the surgeon inside the closed chest. A self-sufficient Cargo Module is developed as a transportation and depot device. It provides an "inside equipment store" for the surgeon. With the Assist Module the surgical equipment, tissue and vessels can be positioned on a desired place in the operating field. This module provides the surgeon an "assistant" inside the closed chest.

The medical engineering program of Forschungszentrum Karlsruhe.

The research activities of the Forschungszentrum Karlsruhe on minimally-invasive surgery (MIS) have for several years improved techniques and instrumentation for different types of MIS. Many types of instruments and robotic devices have been developed and new techniques implemented. In this paper we present the most recent results from our different projects, such as endoscopic heart surgery, tracking systems, a camera guidance device, telemanipulator systems, minimally-invasive breast biopsy in closed-bore MRI, endoscopic training simulators and developments using smart materials (e.g. Nitinol).

Design of a tribocorrosion bioreactor for the analysis of immune cell response to in situ generated wear products.

Adverse local tissue reactions to wear debris and corrosion products have lead to a sharp decline in the use of metal-on-metal (MOM) total hip athroplasties (THAs) clinically. Today, approximately 1 million patients are still carrying such a device. To gain a better understanding of the effect of wear and corrosion products on cells within the joint environment, it is important to generate conditions in vitro that resemble the in vivo system as closely as possible. In this paper, we present a novel tribocorrosion bioreactor that enables the simultaneous conduction of tribocorrosion and cell-culture experiments. In this setup, macrophage cell cultures are located in direct proximity to a tribological interface mimicking the sliding conditions of THA and are exposed to wear and corrosion products as they are generated. These products may include meta-stable species and metallo-organic complexes that have not been considered in earlier studies. The combination of standard tribological, electrochemical, and biological techniques is associated with several challenges that are described here in detail.

Prohepcidin and iron metabolism parameters in the obese elderly patients with anemia.

OBJECTIVE: To examine the impact of a body fat content on the concentration of a serum prohepcidin, iron metabolism parameters and inflammation markers in elderly patients with microcytic or normocytic anemia. DESIGN: Clinical study with biochemical and anthropometric measurements. SUBJECTS: Fifty two elderly patients (19 male, 33 female) with anemia, 65-91 years of age. MEASUREMENTS: Prohepcidin, ferritin, soluble transferrin receptor, erythropoietin and interleukin-6 were measured using commercially available ELISA kits. Iron, TIBC, transferrin, C-reactive protein and complete blood count were assayed using standard laboratory methods. Body fat content, fat distribution and protein nutrition state parameters were assessed by means of anthropometry. RESULTS: Mean serum prohepcidin levels were significantly higher in patients with high body fat content in comparison to patients with normal body fat content (224,85 vs 176,6 ng/ml). Prohepcidin levels of the elderly patients with anemia were positively correlated with biceps, subscapular and suprailiac skinfold thickness or body fat mass percentage. In our study serum prohepcidin levels do not correlate with any iron parameters or inflammation markers. CONCLUSION: Summing up, the results of this study indicate that increased prohepcidin concentration, observed in obese elderly patients with anemia, may play an important role in iron deficiency development.