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At least 19 recordsLinked to original sources

[Hemodynamic effects of amrinone or milrinone in infant after right heart bypass operation].

After right heart bypass operation, dopamine was continuously infused at 5 micrograms/kg/min. The patients had a stable hemodynamic status but relatively low SvO2, low urine output and peripheral insufficiency. Amrinone was continuously infused at 10 micrograms/kg/min in 5 patients (Group A), or milrinone was continuously infused at 0.5 microgram/kg/min in 5 patients (Group M). After infusion of amrinone or milrinone, arterial blood pressure relatively decreased and heart rate relatively increased. But heart work index did not increased. SvO2 relatively increased. Mean pulmonary artery pressure relatively decreased. The administration of amrinone (Group A) produced relatively thrombocytopenia compared with milrinone (Group M). Two patients had supraventricular arrhythmia in Group A. A patient had ventricular arrhythmia and another patient supraventicular arrhythmia. These patients treated using temporary antiarrhythmia drug or temporary pacing. When the patients discharged, they recovered the normal sinus rhythm. In conclusion, after right heart bypass operation in infants, infusion of amrinone or milrinone appears to be effective and safe combining with dopamine.

Amrinone↗

[Experience of coronary artery bypass grafting on the beating heart with right heart bypass; 3 cases of octogenarian].

Right heart bypass (RHB) yields more stable hemodynamics by increasing left ventricular preload and collapse right ventricular chamber during the displacement of the heart on beating heart coronary artery bypass grafting (CABG). Recently beating heart CABG gaining popularity, and the indications for CABG have increasingly expanded to elderly person. Using RHB while exposing posterior branches by displacing the beating heart, we have attempted to make total revascularization in beating heart CABG. We performed beating heart CABG with RHB in 3 cases of octogenarian. All patients had left main trunk lesion and needed revascularization of posterior vessels. Introduction of RHB enabled us to approach to posterior target vessels in better exposure and under greater hemodynamic stability. All three patients had no complications postoperatively. Strictly speaking CABG with RHB is not off-pump CABG, but RHB system does not include either artificial lung or manipulation of the aorta. Therefore we think it is very effective support system which enables multiple coronary revascularization for elderly person.

Aged↗

Beating coronary bypass with right-heart bypass. A safer option in patients at high risk for stroke.

Two patients with bilateral obstructive carotid artery disease underwent beating heart coronary bypass including revascularization of the circumflex branch using right-heart bypass in a stable hemodynamic state. Without this mechanical support, lifting the left ventricle for the exposure of the posterior wall could impair the hemodynamic state of the patient. Right-heart bypass in addition to aortic no-touch technique can be a safer option for complete coronary revascularization in patients at high risk for neurological complications.

Aged↗

Right ventricular function during left heart bypass.

Right heart failure may occur during mechanical support of the left ventricle (LV). Right ventricular (RV) functional changes were studied in eight dogs (26.9 +/- 1.4 kg) subjected to various degrees of left heart bypass (LHBP) with a roller pump. The venous return to the right atrium was controlled with a second pump. RV function was evaluated by peak RV developed pressure, its first derivative (dp/dt), and mean RA pressure measurements. Left atrial, LV, and aortic pressure and both roller pump flows were determined. Incremental increases in LHBP flow ratio ([LHBP flow x 100] divided by venous return flow) to 60%, 90%, and 100% were associated with decrements in RV dp/dt from the control of 212 +/- 17 torr/sec to 192 +/- 16, 178 +/- 16, and 168 +/- 13 torr/sec, respectively. Biventricular bypass or total cardiopulmonary bypass with extracorporeal membrane oxygenation seems to be indicated if LHBP flow ratio greater than 90% is required to maintain adequate body perfusion. Maximal LV decompression to obtain the greatest reduction of LV myocardial oxygen consumption may not be the ideal goal during LV mechanical assistance.

Animals↗

[Two successful cases of total extracardiac right heart bypass].

We reported two successful cases of extracardiac total right heart bypass using 20 mm EPTFE conduit (modified total cavopulmonary connection). They were seven-year-old boy and nine-year-old girl. Both patients had complex heart disease including cyanosis, atrioventricular discordance. We selected this technique instead of modified Fontan or conventional total cavopulmonary connection because of safeness and easiness of surgery and the hemodynamic benefits. They don't have any restriction for their life postoperatively. We propose this technique as an alternative surgical option in candidates for a Fontan procedure or conventional total cavopulmonary connection.

Blood Vessel Prosthesis↗

Veno-venous bypass to prevent myocardial ischemia during right heart bypass operation in PA, IVS, and RV dependent coronary circulation.

There is a risk of myocardial ischemia in patients with pulmonary atresia and intact ventricular septum associated with right ventricle dependent coronary circulation, especially during open heart operation. Cardiopulmonary bypass unloads the right ventricle, and thereby reduces the coronary perfusion pressure in an area that is wholly or partly dependent on the right ventricle. We present a veno-venous bypass technique to keep the right ventricle beating and ejecting to supply the oxygenated blood into the right ventricle dependent myocardium and consequently to prevent myocardial ischemia during right heart bypass operation.

Anastomosis, Surgical↗

The history of right heart bypass before Fontan.

Numerous clinical and experimental studies have suggested that adequate pulmonary blood flow and normal central venous pressure may be maintained without significant contribution of right ventricular function. These data induced experimental and clinical research in the quest for complete bypass of the right heart. More than 40 different operations have been designed to bypass the right ventricle. Partial right ventricular bypass was achieved in 1949 by anastomosing the superior vena cava to the pulmonary artery in animal experiments. In 1950 such as operation was successfully performed clinically for the first time. Complete bypass of the right heart was accomplished for the first time experimentally in 1954 by performing a superior vena cava-to-right pulmonary artery anastomosis and implanting the inferior vena cava into the left atrium. Successful clinical bypass of the right heart was carried out later by implanting both vena cavae into the pulmonary circulation. Until the cavopulmonary shunt conclusively proved the validity of the concept that compensated circulation is possible without participation of the right ventricle, surgeons did not fully understand its possible relevance in clinical situations. The development of partial and complete right heart bypass procedures, both experimental and clinical, not only presented us with viable alternatives to aortopulmonary shunts like the Blalock-Taussig or Potts anastomosis, but it also opened the way to development of new operations such as the Fontan procedure which are based on the principle of low pressure pulmonary flow and right ventricular bypass.

Anastomosis, Surgical↗

[Tricuspid valve replacement using right heart bypass in patient with liver cirrhosis].

A successful case with liver cirrhosis underwent re-tricuspid valve replacement (TVR) using right heart bypass is reported herein. A 59-year-old lady previously undergone tricuspid valve replacement with bioprosthetic valve had suffered from exertional fatigue as the feature of congestive heart failure. She also presented severe liver dysfunction owing to chronic hepatitis and cardiac liver cirrhosis. She was diagnosed with structural deterioration of bioprosthesis in tricuspid position. She underwent re-TVR with right heart bypass consisted of centrifugal pump, heparin coating circuit and blood reservoir. This system lacked of membranous oxygenator in order not to activate various kinds of chemical mediator which leads to postoperative liver dysfunction. Postoperative course was uneventful and she is doing well 1 year after the operation. Although the mortality of the TVR in the patient with cirrhosis remains still high, this new technique seems to provide better outcome in this kind of patients.

Bioprosthesis↗

Hemodynamics of different degrees of right heart bypass: experimental assessment.

BACKGROUND: Although their assessment could be of the utmost importance to determine the surgical treatment for patients with univentricular hearts, differences in ventricular performance between partial and complete right heart bypass remain to be defined. METHODS: Three different degrees of right heart bypass were investigated in 5 mongrel dogs: (1) superior vena cava to both pulmonary arteries shunt (SCP); (2) inferior vena cava to both pulmonary arteries shunt (ICP); and (3) both venae cavae to both pulmonary arteries shunt (BCP). Hemodynamic studies included evaluation of the cardiac index and left atrial pressure as a function of the degree of right heart bypass. RESULTS: By maintaining the mean left atrial pressure at 5 mm Hg, cardiac indexes were 1.98 +/- 0.25, 1.67 +/- 0.29, and 1.33 +/- 0.21 L.min-1.m-2 for SCP, ICP, and BCP shunts, respectively (p = 0.001). When keeping the cardiac index constant, mean left atrial pressures were 5.2 +/- 0.8, 5.5 +/- 0.9, and 7 +/- 0.7 mm Hg for SCP, ICP, and BCP shunts, respectively (p = 0.001). CONCLUSIONS: Increasing degrees of right heart bypass are associated with a significant decrease in ventricular performance in this experimental model.

Animals↗

Refined anaesthesia for implantation of engineered experimental aortic valves in the pulmonary artery using a right heart bypass in sheep.

The feasibility of an anaesthetic protocol developed for surgery during right heart bypass in sheep is reported. Seven female Suffolk sheep, weighing 25-35 kg, were selected for the study. Premedication consisted of midazolam and methadone (both 0.1 mg kg(-1) intravenously). Anaesthesia was induced with propofol (2-4 mg kg(-1)) and maintained with isoflurane in oxygen and continuous rate infusions of propofol (5-7 mg kg(-1 )h(-1)) and fentanyl (5 microg kg(-1) bolus, 5 microg kg(-1) h(-1)). Cisatracurium (0.2 mg kg(-1)) provided muscle relaxation. A standard roller pump was used for the extracorporeal circulation. Drugs administered to maintain blood pressure and heart rate within acceptable levels included phenylephrine (3-4 microg kg(-1)), ephedrine (0.1-0.2 mg kg(-1)), nitroglycerine (50-150 microg kg(-1) h(-1)) and metoprolol succinate (30-80 microg kg(-1)). Electrolytes were infused as needed. Postoperative analgesia was provided by an intercostal block (15 mL 0.5% bupivacaine + epinephrine), carprofen (4 mg kg(-1)) and an opioid (methadone 0.1 mg kg(-1) or buprenorphine 0.01 mg kg(-1)). One sheep became hypoxic during the bypass (PaO(2) 47.7 mmHg). Irregularities of the electrocardiogram were observed during manipulation of the heart in all animals. During the initial phase of the bypass, blood pressure decreased in all sheep, accompanied by dilatation of the heart and large intrathoracic veins in five sheep. With appropriate treatment, blood pressure was restored and easily maintained until the end of the bypass. Weaning from the bypass, using an infusion of nitrates, was smooth. One sheep required a blood transfusion because of severe blood loss and another sheep died postoperatively from respiratory complications. Minor irregularities of the electrocardiogram observed during manipulation of the heart were not life threatening and required no treatment. Decreases in blood pressure at the beginning of the bypass can be expected and require treatment. Nitrates are useful in avoiding volume overload during weaning. The anaesthetic protocol is acceptable for surgery under right heart bypass in sheep.

Anesthesia↗

New technique of right heart bypass in congenital heart surgery with autologous lung as oxygenator.

BACKGROUND: Modifications have been made in cardiopulmonary circuit to reduce the inflammatory deleterious effects and cost. We present our experience of one such right heart bypass (RHB) circuit utilizing autologus lung as oxygenator. METHODS: From September 2001 to December 2002, 15 patients underwent congenital heart surgery with this technique. Bypass circuit consisted of a reservoir and a roller pump along with a cardiotomy sucker. The left pulmonary artery and main pulmonary artery were used for arterial return, and venous drainage was achieved with innominate vein cannulation. Inferior vena cava cannulation was performed when needed. Thirteen patients underwent bidirectional Glenn shunt surgery (12 to 24 months, 6 to 10 kg). One patient (26 years old) underwent central shunt with enlargement of confluence and left pulmonary artery. Another patient (18 months old) underwent 1.5 ventricle repair. RESULTS: There were no hospital deaths. Mean flow achieved on RHB was 0.57 +/- 0.3 L/min/m(2), central venous pressure was 3.3 +/- 1.8 mm Hg (0 to 7 mm Hg), and mean arterial pressure could be maintained satisfactorily in all patients (54 +/- 14 mm Hg). Mean RHB time was 54 +/- 14 min. Mean central venous pressure was 10.1 +/- 2.4 mm Hg after procedure and saturation was similar to that on (RHB 88% +/- 8%). The mean amount of drainage was 9.1 +/- 4.2 mL/kg per 24 hours. Avoiding an oxygenator and reducing the number of tubings achieved a combined cost savings of 40% for all procedures. CONCLUSIONS: Right heart bypass is a simple, safer, and less expensive alternative to conventional cardiopulmonary bypass. This technique allows effective decompression of superior vena cava, adequate oxygenation, and predicts saturation after Glenn shunt. It can also be applied for central shunts and pulmonary artery reconstructions with cost containment.

Adult↗

Right heart bypass for left circumflex coronary artery bypass grafting.

Displacement of the heart to expose the left circumflex artery (LCX) causes hemodynamic disturbance during off-pump coronary artery bypass grafting (CABG). We applied right heart bypass (RHB) using a heparin-coated centrifugal pump without an oxygenator in an attempt to stabilize the hemodynamics. Five mongrel dogs (15.5-20 kg) were used. Hemodynamic parameters were continuously monitored at a fixed rate of 80 beats/min. The LCX was exposed with the use of an Octopus Tissue Stabilizer. After baseline data were obtained, each dog was placed in the Trendelenburg position. Finally, RHB was established with different pump flows. LCX exposure caused a significant decrease in aortic flow (to 33.1% +/- 13.1% of the baseline value) and arterial mean pressure (to 68.3% +/- 8.5%) (P < 0.001). Trendelenburg positioning caused these values to recover to 57.1% +/- 6.7% and 72.5% +/- 7.7%, respectively. RHB with 50% flow significantly improved the hemodynamic values, although 100% flow significantly increased LAP by 134.8% +/- 19.7% (P < 0.01). Tilting of the canine heart to expose the LCX caused significant deterioration of the hemodynamic values. Trendelenburg positioning was moderately effective, and RHB very effective, in improving the hemodynamics. In a limited number of cases, an appropriate flow of RHB may provide safe hemodynamic assistance during off-pump CABG of the LCX.

Animals↗

Pulmonary artery augmentation using autologous vena cava in right heart bypass operations.

We obtained good results in the right heart bypass operation concomitant with the pulmonary arterial augmentation using the vena cava in 7 patients. We report the techniques used in 2 representative patients. The techniques used were a hemi-Fontan procedure with large superior vena caval patches and a bidirectional cavopulmonary shunt with superior vena caval interposition. These techniques have advantages in that the augmented pulmonary arteries have growth potential and low thrombogenicity because the procedures can be performed without the use of prosthetic materials or xenografts, especially in cases in which it is impossible to use the autologous pericardium.

Cardiopulmonary Bypass↗

Cardioprotective effect of ischemic preconditioning on global myocardial ischemia in a sheep right heart bypass model.

OBJECTIVES: Ischemic preconditioning has been used to induce the myocardium to adapt to ischemic stress preceded by short periods of ischemia and reperfusion. We used a sheep right heart bypass model with a conductance catheter to assess the cardioprotective effect of ischemic preconditioning on 30-minute normothermic global myocardial ischemia. METHODS: Ischemic preconditioning was conducted in 6 sheep in 35-minute aortic cross-clampings interspersed with 5 minutes of reperfusion during cardiopulmonary bypass, with 6 sheep as time-matched controls. Global myocardial ischemia was subsequently achieved in 30-minute aortic cross-clamping with left ventricular unloading during normothermic cardiopulmonary bypass. Weaning from cardiopulmonary bypass was conducted 40 minutes after reperfusion. Before ischemia and 40, 70, and 100 minutes after reperfusion, left ventricular pressure-volume loops were measured using a conductance catheter during right heart bypass preparation. Left ventricular contractility, diastolic function, and mechanical efficiency were then evaluated. Right heart bypass was instituted to control the preload and to decompress the right ventricle completely, thereby eliminating parallel conductance variation. RESULTS: No differences in the studied parameters were seen between ischemic-preconditioning and control groups before ischemia. Left ventricular contractility, diastolic function, and mechanical efficiency in the ischemic-preconditioning group were significantly superior to those in the control group after reperfusion. CONCLUSIONS: Ischemic preconditioning attenuates postischemic myocardial dysfunction in a sheep model using 30-minute unloaded normothermic global myocardial ischemia. Ischemic preconditioning would thus be clinically significant when the ischemic damage is severe.

Animals↗

Total extracardiac right heart bypass using a polytetrafluoroethylene graft.

BACKGROUND: With regard to hemodynamics and late arrhythmias, total cavopulmonary connection has been accepted as a superior technique as compared to Fontan type procedures. However, intra-atrial baffles for lateral tunnel or conduit remain construction retain some similar disadvantages. PATIENTS AND METHODS: As an alternative to total cavopulmonary connection, total extracardiac right heart bypass using a polytetrafluoroethylene tube for the inferior vena cava to pulmonary artery connection may obviate some problems. Five patients with complex heart disease necessitating one ventricle repair underwent this procedure successfully. RESULTS: Aortic cross-clamp time ranged from 0 to 24 minutes (mean = 15.8 min). No case required takedown or an additional step. Although the follow-up periods have been relatively short (mean = 19 months), all patients are well and no arrhythmic event or thromboembolic episode has occurred. CONCLUSIONS: As a simple, safe, and reproducible procedure, total extracardiac right heart bypass is an alternative to Fontan or total cavopulmonary connection procedure.

Blood Vessel Prosthesis↗