Minimally invasive coronary bypass surgery: an example for optimal teamwork between cardiologists and cardiac surgeons?
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Cardiology↗
Biomedical subjects
J Bonatti
Publications and source records attributed to J Bonatti.
Mucosal tissue oxygenation of the porcine jejunum during normothermic cardiopulmonary bypass.
Cardiopulmonary bypass (CPB) has been associated with intestinal tissue hypoxia, but direct measurements of mucosal oxygenation have not been performed. In anaesthetized pigs, jejunal mucosal oxygen tension and microvascular haemoglobin oxygen saturation were measured by a Clark-type electrode and tissue reflectance spectrophotometry. In pigs, normothermic CPB with systemic oxygen transport equivalent to baseline values was performed. In control animals, mucosal oxygen tension and mucosal haemoglobin oxygen saturation were mean 5.01 (SD 1.08) kPa and 38.0 (2.3)%, respectively. CPB was associated with a decrease in mucosal oxygen tension to 2.26 (1.21) kPa, decrease in mucosal microvascular haemoglobin oxygen saturation to 26.0 (3.9)% and appearance of oscillations in mucosal microvascular haemoglobin oxygen saturation. With CPB, arterial lactate concentrations increased from 1.77 (1.37) to 3.52 (1.58) mmol litre-1, but transvisceral lactate and splanchnic venous-arterial carbon dioxide tension gradients remained unchanged. Our results support the concept that CPB is associated with diminished oxygenation of intestinal mucosa that is probably caused by regional redistribution.
Animals↗
Beating heart axillocoronary bypass for management of the untouchable ascending aorta in coronary artery bypass grafting.
OBJECTIVES: Cannulation and clamping of a severely atherosclerotic ascending aorta during coronary artery bypass grafting (CABG) can lead to cerebral embolization of atheromatous debris and should therefore be avoided whenever possible. A variety of surgical techniques including performance of extraanatomical coronary bypass conduits has been described to solve this problem. We report on a preliminary series of four patients in whom the axillary artery was used as an inflow vessel for venous coronary artery bypass grafts which were performed on the beating heart in order to achieve an aortic no touch concept. METHODS: The axillary artery was exposed between the pectoralis major muscle and the deltoid muscle via an infraclavicular incision. A saphenous vein graft of at least 40 cm in length was sutured to the axillary artery and then brought into the pericardial cavity following an intercostal and transpleural route. The graft was anastomosed to the target vessel using local coronary occlusion. The procedure was carried out via sternotomy in three patients who also received additional internal mammary artery in situ grafts for adequate coronary revascularization. In one high risk patient an isolated axillocoronary bypass was performed in a minimally invasive fashion via anterolateral minithoracotomy. RESULTS: The procedure was completed without major technical difficulties in all four patients. The mean graft length required was 33.2 +/- 1.6 cm, postoperative ultrasonic duplex scans of the axillocoronary grafts revealed a mean flow of 62.5 +/- 23.6 ml/min. No stroke or brachial plexus injury occurred. Three patients are in angina class I (Canadian Cardiovascular Society Classification), one patient is in class II postoperatively. After a mean follow-up of 11.5 +/- 6.6 months postoperatively all grafts remain patent. CONCLUSION: Axillocoronary bypass grafting can be easily performed for management of the untouchable ascending aorta. Straightforward surgical technique and the accessibility to noninvasive diagnostics seem to offer advantages over other extraanatomical bypass grafts.
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Ascending aortic atherosclerosis--a complex and challenging problem for the cardiac surgeon.
Ascending aortic atherosclerosis is an increasingly recognized problem in cardiac surgery. It is the most important risk factor for perioperative stroke and seems to be in part responsible for postoperative neurobehavioral changes. Patients exhibiting ascending aortic atherosclerosis have a significantly reduced survival rate and are at considerable risk for spontaneous embolic stroke during the long-term postoperative course. Preoperative noninvasive diagnosis and intraoperative assessment by inspection or palpation of the aorta are insensitive. Intraoperative epiaortic ultrasound scanning has emerged as a most helpful tool for the diagnosis of ascending aortic atherosclerosis and has revealed major insights into the nature and distribution of this disease. Management strategies range from minimally invasive aortic "no touch" techniques to maximally invasive procedures, including application of deep hypothermic circulatory arrest. Operative modifications in coronary artery bypass grafting include avoidance of aortic crossclamping, alternative methods of aortic crossclamping and placement of all arterial in situ bypass conduits, Y-grafts or extra-anatomical bypass grafts. Other operative strategies include modifications of the arterial cannulation site, replacement of the ascending aorta or ascending aortic endarterectomy. One of the most recently developed methods is embolic capture by intraaortic filters. Increased awareness of ascending aortic atherosclerosis is critical in order to prevent the devastating complications it can cause during cardiac surgery.
Aortic Diseases↗
Atrial natriuretic peptide-induced release of cyclic guanosine monophosphate by coronary bypass grafts.
BACKGROUND: Superior long-term patency rates of the internal mammary artery (IMA) versus saphenous vein (SV) after coronary artery bypass grafting are well documented. Higher production rates of vasodilating and platelet-inhibiting mediators (prostacyclin and nitric oxide) by the IMA seem to have a major impact on its long-term durability and resistance to coronary artery graft disease. For the right gastroepiploic artery (RGEA) marked release of protective mediators is reported as well. The vasodilating effect of cyclic guanosine monophosphate (cGMP) released after stimulation by atrial natriuretic peptide might serve as another graft protective system. The aim of the present study was to determine cGMP release by IMA, RGEA, and SV after atrial natriuretic peptide challenge. METHODS: Samples of human IMA (n = 19), RGEA (n = 7), and SV (n = 18) discarded during coronary artery bypass grafting were stimulated with 10(-6) mol/L atrial natriuretic peptide after a resting phase in nutrient medium. Release of cGMP was determined by 125-iodide radioimmunoassay. RESULTS: Basal cGMP production rates of the IMA (759.9 +/- 277.0 fmol/cm2) and RGEA (739.9 +/- 186.0 fmol/cm2) were higher than production rates of SV (281.2 +/- 64.0 fmol/cm2). Application of atrial natriuretic peptide led to a statistically significant increase of cGMP release in IMA grafts (1,939.3 +/- 778.0 fmol/cm2), whereas RGEA (618.4 +/- 141.3 fmol/cm2) and SV (221.7 +/- 64.5 fmol/cm2) remained at basal levels (p < 0.05). CONCLUSIONS: From these data we conclude that the IMA in comparison with the RGEA and SV produces more extracellular cGMP when stimulated by atrial natriuretic peptide. This effect might support the cGMP-mediated protective properties of nitric oxide and could underline the extraordinary suitability of the IMA as a bypass conduit.
Abdominal Muscles↗
Myocardial damage after minimally invasive coronary artery bypass grafting on the beating heart.
BACKGROUND: In conventional coronary artery bypass grafting, the rate of perioperative myocardial infarction is reported in the 2% to 6% range; however, significantly higher rates are observed if sensitive myocardial marker proteins are used to detect perioperative myocardial damage. For minimally invasive direct coronary artery bypass grafting, few data are available concerning myocardial marker protein release. METHODS: Fifteen consecutive patients (11 male, 4 female; mean age, 59.6 +/- 8.5 years) received minimally invasive direct coronary artery bypass grafting procedures via minithoracotomy on the beating heart. Electrocardiography and transesophageal and transthoracic echocardiography as well as determination of creatine kinase-MB mass concentration and cardiac troponin I level were used for ischemic monitoring. RESULTS: One patient had a perioperative myocardial infarction according to standard criteria and died despite mechanical circulatory support. Determination of cardiac troponin I level showed small but definitive ischemic damage in 4 of 9 patients (44%) who presented transient ischemic signs intraoperatively or postoperatively. In 2 of these 4 patients pathologic findings could be detected on angiographic restudies. CONCLUSIONS: Subclinical myocardial injury is a common event in minimally invasive coronary artery bypass grafting on the beating heart. Cardiac troponin I could serve as an adequate diagnostic tool for diagnosis of perioperative myocardial infarction in minimally invasive direct coronary artery bypass grafting.
Aged↗
Axillocoronary bypass for severely atherosclerotic aorta in coronary artery bypass grafting.
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Aged↗
Single coronary artery bypass grafting--a comparison between minimally invasive 'off pump' techniques and conventional procedures.
OBJECTIVE: At present, few studies directly comparing minimally invasive and conventional coronary artery bypass grafting are available. The aim of the present study was to evaluate the clinical outcome of the two techniques. METHODS: We retrospectively compared our first consecutive 20 patients undergoing minimally invasive coronary artery single bypass grafting on the beating heart (group I) with 23 consecutive patients receiving single coronary artery bypass via sternotomy using cardiopulmonary bypass and cardioplegia (group II). The procedures were performed during the period from Jan 1, 1994 to Feb 20, 1997. There were no significant differences in demographic data. RESULTS: Statistically significant differences were found concerning total operative time (172.6 min in group I and 149.6 min in group II P = 0.0009) and myocardial ischemic time (23.7 min local coronary occlusion time in group I and 17.6 min aortic cross-clamp time in group II P = 0.03. Patients treated minimally invasive received significantly fewer blood transfusions (25.0% vs. 69.6% P = 0.0035) and were discharged significantly earlier from the hospital (admission rate on the fifth postoperative day 68.4% in group I vs. 100.0% in group II P = 0.0004). CONCLUSION: We conclude that minimally invasive coronary artery bypass grafting on the beating heart in comparison to conventional single coronary artery bypass grafting during the learning curve requires longer operative times but can reduce blood transfusion requirements and hospital stay.
Blood Transfusion↗
Anatomical studies concerning technical feasibility of minimally invasive axillocoronary bypass grafting.
OBJECTIVE: Minimally invasive multiple vessel revascularization has been accomplished using all arterial graft concepts and aortocoronary vein grafts. The aim of the present study was to determine the technical feasibility of minimally invasive axillary artery to coronary artery vein grafting in the human cadaver. METHODS: In seven human cadavers the axillary artery was approached bilaterally via a small incision above the anterior axillary fold. The left anterior descending coronary artery system and the right coronary artery system were exposed via a left anterior minithoracotomy and a subxiphoid incision respectively. Saphenous vein grafts were anastomosed end to side to the axillary artery and brought to the target vessels following a transpleural route. The vein grafts were then sutured to the left anterior descending artery and to the posterior descending artery through the mini-incisions. RESULTS: Axillocoronary bypass grafting to the left anterior descending artery was performed successfully in seven cases, axillocoronary bypass grafting to the posterior descending artery was accomplished in six cases. The mean length of the mini-incisions was as follows: left axillary artery exposure 5.1+/-1.5 cm, right axillary artery exposure 5.5+/-2.0 cm, left anterior minithoracotomy 10.8+/-1.9 cm, subxiphoid incision 9.4+/-1.9 cm. The mean length of saphenous vein required for the left axillary artery to left anterior descending artery bypass was 18.9+/-2.8 cm, the mean length of vein required for the right axillary artery to posterior descending artery bypass was 26.0+/-2.6 cm. This was significantly longer than the aortocoronary route (ascending aorta to left anterior descending artery 12.5+/-2.2 cm P = 0.0001, ascending aorta to posterior descending artery 18.3+/-2.9 cm P < 0.0001). CONCLUSION: From this study we conclude that minimally invasive axillocoronary venous bypass grafting to the left anterior descending artery system and to the distal right coronary artery system is technically feasible in the human cadaver.
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Stimulated prostacyclin release by conduits used for coronary artery bypass grafting.
A direct comparison of the three coronary artery bypass conduits internal mammary artery (IMA), right gastroepiploic artery (RGEA), and saphenous vein (SV) concerning arachidonic acid (AA) stimulated release of the vasodilating and platelet inhibiting mediator prostacyclin was the aim of the present study. Pieces of saphenous vein (n = 16), right gastroepiploic artery (n = 8), and internal mammary artery (n = 19) were obtained from patients undergoing coronary artery bypass grafting. After a resting phase of 30 min in HEPES medium arachidonic acid (AA) was added in order to stimulate prostacyclin release. Time-dependent production of the stable prostacyclin metabolite 6-keto-prostaglandin F1 alpha was determined following stimulation. Under basal conditions the IMA (12.4 ng/cm2) and RGEA (12.0 ng/cm2) released more prostacyclin than saphenous vein (4.0 ng/cm2). After AA stimulation 6-keto-prostaglandin F1 alpha release at 30 min was as follows: IMA 806.0 ng/cm2, RGEA 35.9 ng/cm2, SV 82.3 ng/cm2 (p < 0.0001 within grafts, p < 0.0001 between grafts, ANOVA for repeated measures). The internal mammary artery in comparison with the right gastroepiploic artery and saphenous vein seems to be better protected against local thrombotic events and development of coronary artery graft disease with the aid of the vasodilating and platelet inhibiting mediator prostacyclin.
Arachidonic Acid↗
Preliminary experience with minimally invasive coronary-artery bypass surgery combined with coronary angioplasty.
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Angioplasty, Balloon, Coronary↗
Inotropic treatment and intestinal mucosal tissue oxygenation in a model of porcine endotoxemia.
OBJECTIVE: To evaluate the dose-related effects of dopamine, dopexamine, and dobutamine on intestinal mucosal tissue oxygenation following short-time infusion of Escherichia coli lipopolysaccharide, which has previously been shown to decrease mucosal tissue oxygenation by 60% of control values. DESIGN: Prospective, randomized, unblinded study. SETTING: Animal research laboratory. SUBJECTS: Anesthetized, mechanically ventilated domestic pigs. INTERVENTIONS: Pigs were infused with 2 microg/kg of E. coli lipopolysaccharide over 20 mins via the superior mesenteric artery. Pulmonary artery occlusion pressure was maintained near 15 mm Hg, using a mixed infusion regimen of Ringer's lactate solution and hydroxyethyl starch. Following endotoxemia, a small segment of the jejunal mucosa was exposed by midline laparotomy and antimesenteric incision. The control group (n = 7) received no further interventions. Pigs in the dopamine (n = 7), dopexamine (n = 7), and dobutamine (n = 7) groups were infused with 2.5, 5, 10, and 20 microg/kg/min of the respective drug via a central venous catheter. MEASUREMENTS AND MAIN RESULTS: Systemic hemodynamics as well as systemic, mesenteric, and femoral blood gas variables were measured using an arterial, a thermodilution pulmonary artery, a superior mesenteric venous, and a femoral venous catheter. Jejunal mucosal tissue PO2 was measured by means of two Clark-type surface oxygen electrodes. Oxygen saturation of jejunal mucosal microvascular hemoglobin was determined by tissue reflectance spectrophotometry. Infusion of endotoxin resulted in pulmonary hypertension. Systemic hemodynamics remained unchanged except for brief decreases in cardiac output and arterial blood pressure. Dopamine, dopexamine, and dobutamine increased systemic oxygen delivery in a dose-related manner by 80% (p < .01), 96% (p = .00), and 129% (p = .00) of values before inotropic treatment. Dopamine increased mucosal tissue PO2 by 109% (10-microg dose, p < .01) and 164% (20-microg dose, p = .00), and mucosal hemoglobin oxygen saturation by 61% (5-microg dose, p < .05), 102% (10-microg dose, p < 01) and 121% (20-microg dose, p = .00). Dopexamine increased mucosal tissue PO2 by 89% (20-microg dose, p < .01) and mucosal hemoglobin oxygen saturation by 26% (2.5-microg dose, p < .05) and 35% (5-, 10-, and 20-microg dose, p < .05). In the dobutamine and control groups, no significant effect on either mucosal tissue PO2 or hemoglobin oxygen saturation was observed. CONCLUSIONS: In this model of porcine endotoxemia, dopamine and, to a lesser extent, dopexamine increase intestinal mucosal tissue oxygenation. Of all three inotropes used, dobutamine has the most pronounced effect on systemic oxygen delivery, but it does not improve mucosal tissue oxygenation. Selective vasodilation within the intestinal mucosa, mediated mainly by dopamine-1 receptors, seems to explain the observed intestinal mucosal effect of dopamine and dopexamine.
Animals↗
Percutaneous venoarterial extracorporeal membrane oxygenation for emergency mechanical circulatory support.
In this retrospective study we report our initial experience with percutaneous venoarterial extracorporeal membrane oxygenation in the emergency treatment of intractable cardiogenic shock or pulseless electrical activity. Between January 1994 and July 1995, percutaneous venoarterial extracorporeal membrane oxygenation was attempted in seven patients (pulseless electrical activity, five patients; cardiogenic shock, two patients). In two of the seven patients, efforts at arterial cannulation resulted in cannula perforation at the level of the iliac artery. In the remaining five patients, percutaneous venoarterial extracorporeal membrane oxygenation could be established and was maintained for 3-84 h. Major bleeding remained a common complication during extracorporeal membrane oxygenation despite the use of heparin-coated bypass circuits and was responsible for death during extracorporeal membrane oxygenation in one patient. The remaining four patients could be weaned from mechanical circulatory support within 24 h, two after surgical interventions (resection of right atrial tumor, heart transplantation), one after thrombolytic therapy. In one patient, cardiac function recovered spontaneously after 6 h on venoarterial extracorporeal membrane oxygenation. Three patients were discharged from hospital, two of them made a full recovery, one sustained severe hypoxic brain injury. A few patients with intractable cardiogenic shock or pulseless electrical activity can be resuscitated with the help of emergency percutaneous venoarterial extracorporeal membrane oxygenation. Emergency venoarterial extracorporeal membrane oxygenation is associated with a high rate of complications and its use should therefore be limited to selected patients with a rapidly correctable underlying cardiopulmonary pathology (anatomic, metabolic or hypothermic) who do not respond to conventional advanced cardiac life support.
Emergencies↗
Spinal cord protection in descending and thoracoabdominal aortic surgery--the role of distal perfusion.
The use of distal perfusion in descending thoracic and thoracoabdominal aortic surgery remains a controversial issue. Few mainly retrospective studies which directly compare simple clamping with distal perfusion are available. The aim of the present study was such a comparison in an own series of descending and thoracoabdominal aortic replacement. The records of 29 patients who underwent descending or thoracoabdominal aortic replacement between 1988 and 1994 were retrospectively reviewed. Patients were divided into two groups. Group I consisted of 14 patients who received aortic replacement using simple clamping, group II was represented by 15 patients who were operated with distal perfusion techniques. In group II left heart bypass with a centrifugal pump was used in 3 patients, and partial cardiopulmonary bypass with a roller pump in 12 patients. The paraplegia/paraparesis rate was 28.6% in group I and 0.0% in group II (p = 0.0258). There were no statistically significant differences regarding surgical revision for bleeding (14.3% in group I, 14.0% in group II), postoperative renal failure (14.3% in group I 13.3% in group II), postoperative ventilator dependence (9.0 days in group I, 11.2 days in group II), rate of postoperative multisystem organ failure (26.7% in group I, 33.3% in group II), length of stay in the ICU (13.6 days in group I and 13.9 days in group II), and 30-day mortality (21.4% in group I and 33.3% in group II). Methods of distal perfusion in comparison to simple clamping can lead to a lower paraplegia/paraparesis rate in descending and thoracoabdominal aortic surgery.
Adult↗
[A new cardiac pacemaker stimulation technology (autocapture) allows, with unchanged life expectancy, reduction of generator size by half].
Energy delivery (stimulation amplitude) of a pacemaker should be adjusted to the depolarisation threshold of the heart, which is a nonconstant magnitude. As programming of the stimulation amplitude is time-consuming, many pacemakers are never adjusted to the measured threshold referring to energy delivery. The unnecessary energy loss subsequently reduces the longevity of the implanted devices and remains the weak point of modern pacemakers. Autocapture function (automatic stimulation threshold search, subsequently automatic amplitude regulation 0.3 V above measured threshold, evoked response detection to verify the efficacy of every stimulus and back up pulse in case of loss of capture) is for the first time realized in an extremely small, rate adaptive, multiprogrammable single chamber pacemaker (Microny SR+ 2425T). The pulse generator was tested in a multicentric, european clinical investigation study. These pacemakers were implanted in 8 patients (5 male, 3 female) between December 1994 and April 1995. Automatic measurement of Autocapture threshold revealed 0.7 +/- 0.15 V at implantation, 1.5 +/- 0.3 V after 1 month, 1.3 +/- 0.14 V after 6 months and 1.3 +/- 0.14 V 1 year after implantation. A safety margin of 0.3 V is added to the threshold value to secure capture, therefore mean stimulation amplitude is 1.6 V after 12 months implantation time. The Autocapture feature minimizes current drain and that means that this extremely small generator provides a comparable life as the twice as large common generators used at present time.
Aged↗
[Percutaneous extracorporal circulation in cardiogenic shock caused by a mixed poisoning with metildigoxin, nifedipine and indapamide].
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Animals↗
Predictors of short-term survival after helicopter rescue.
The purpose of the present retrospective study was to identify easily obtainable predictors of short-term outcome for emergency victims treated by a physician-staffed helicopter emergency medical system (HEMS). The study was conducted at the HEMS unit 'Christophorus 1' based at Innsbruck, Austria. Outcomes for 2139 patients rescued in primary missions during a 3-year period from 1 January 1989 to 31 December 1991 were included in the study. The majority of missions were in response to sports accidents, although missions included a wide spectrum of emergencies. Data were obtained from the 'Christophorus 1' operation protocols and by written, personal, or telephone request from admitting hospitals. Eleven parameters selected from the HEMS flight logs were tested for their predictive value on survival following helicopter rescue. In a univariate analysis, the cause of the emergency, time at the scene, total duration of the emergency mission, patient age, patient gender, severity of the emergency using the National Advisory Committee of Aeronautics (NACA) scoring system, state of consciousness, respiratory status and patient circulatory status each had a statistically significant influence on survival up to 90 days following the emergency. Flight time to the scene and the original specialty of the additionally trained emergency physician had no significant influence on outcome. Multivariate analysis using the Cox proportional hazards model revealed that severity of the emergency by the seven-level NACA scale (P = 0.0001), initial respiratory status (P = 0.0001), time at the scene (P = 0.0108), patient age (P = 0.0047) and patient gender (P = 0.0477) were each independent predictors of short-term survival following physician-staffed helicopter rescue. We conclude that the parameters described above can be used in an initial predictive assessment by the flight physician and the admitting institution.
Accidents↗