Yutaka Kotsuka

Beating Atrial Septal Defect Closure Monitored by Epicardial Real-Time Three-Dimensional Echocardiography Without Cardiopulmonary Bypass

Background—We assessed the feasibility of beating atrial septal defect (ASD) closure monitored by real-time 3D echocardiography (RT3DE). Methods and Results—RT3DE was developed with prototype ultrasound equipment consisting of a high-speed 3D rendering unit with a frame rate of 5 to 10 frames/s. We also developed a prototype semiautomatic suture device and suture cutting system. In the experiment, 12 mongrel dogs were anesthetized, and after median sternotomy, the echo probe was applied directly to the surface of the right atrium. Three surgical maneuvers (balloon atrial septectomy, enlargement of the ASD, and ASD closure) were performed through the atrial port inserted into the right atrial appendage. The heart was then excised, and the area of the ASD measured by RT3DE was compared with its area measured directly. The ASD was successfully closed in all experimental animals except the first 2. Examination of the excised heart showed that none of the sutures were loose. The mean area of the ASD was 82.5±38.6 mm2 when measured by RT3DE and 81.6±38.2 mm2 when measured directly, and there was a significant correlation between the areas measured by RT3DE and those measured directly (echo measurements=1.007×direct measurements+0.337;P <0.0001). A Bland-Altman analysis revealed close agreement between the results obtained by the 2 methods (7.807 mm2 upper and −6.024 mm2 lower limit of agreement). Conclusions—Introduction of RT3DE, a semiautomatic suture device, and a suture cutting system made beating ASD closure without cardiopulmonary bypass possible.

Open stent-grafting for aortic arch aneurysm is associated with increased risk of paraplegia

BACKGROUND Open surgery using the endovascular stent-graft is a novel technique that lessens the invasiveness of surgery for the aortic arch. However, the outcome of this procedure remains uncertain. METHODS Between November 1996 and July 2000, a total of 19 patients underwent open surgery using an endovascular stent-graft for thoracic aortic aneurysms. There were 15 men (78.9%) and 4 women (21.1%). Patient age ranged from 29 to 82 years (mean 69.3 years, median 74 years). Atherosclerotic thoracic aortic aneurysms were present in 17 patients (89.4%) and aortic dissection in 2 patients (10.5%). RESULTS Two patients (10.5%) died in the hospital and 4 patients (21.1%) presented with paraplegia postoperatively. Among the 4 patients with postoperative paraplegia, 1 case was complicated with intraoperative aortic dissection. The other 3 patients with paraplegia had spinal cord ischemic time of more than 60 minutes and intraoperative body weight gain of more than 4 kg. Of these 3 patients, hemodynamic instability after cardiopulmonary bypass was observed in 1 patient and cholesterin embolus in the anterior spinal artery was found at autopsy in another. On univariate analysis, age greater than 75 years was the only risk factor associated with paraplegia (p < 0.05). Autopsy findings for the 2 patients showed that the Adamkiewicz arteries were not blocked by the stent-graft in either patient. CONCLUSIONS Intraoperative aortic dissection, embolization of the intercostal arteries, long ischemic time of the spinal cord, and excessive weight gain during operation may have been associated with the high incidence of paraplegia after open surgery using the endovascular stent-graft.

Predictive risk factors for delayed extubation in patients undergoing coronary artery bypass grafting

Abstract Prolonged mechanical ventilation increases hospitalization costs, airway and lung trauma, and stress. The objective of this study was to elucidate patient characteristics and operative variables that predict delayed extubation in patients undergoing coronary artery bypass grafting (CABG). The records of 167 patients who underwent CABG between 1994 and 1998 were examined retrospectively. The patients were divided into early and delayed extubation groups. Putative factors affecting the duration of intubation were included in a univariate analysis using the t-test and chi-squared test. A logistic regression model was then developed to determine the factors associated with delayed extubation. Forty-four percent of the patients needed prolonged mechanical ventilation (more than 24 h). Univariate predictors of delayed extubation (P < 0.05) were emergency surgery, preoperative use of an intra-aortic balloon pump (IABP), the duration of anesthesia, surgery, cardiopulmonary bypass and aortic cross-clamping, the total volume of fentanyl, lowest rectal temperature, glucose level, perioperative transfusion, bleeding, perioperative heart failure, perioperative insertion of IABP, postoperative transfusion, cardiac index, inspired oxygen fraction (FiO2), arterial oxygen tension (PaO2), the PaO2/FiO2 ratio, and the volume of catecholamine. In the delayed extubation group, the intensive care unit stay was significantly longer (P < 0.001) and re-exploration was required more frequently (P = 0.004). Excellent prediction was provided by a model consisting of six variables: age, duration of surgery, perioperative heart failure, glucose level, postoperative transfusion, and the PaO2/FiO2 ratio. These results suggest that decreasing the cardiopulmonary bypass time, maintaining a low glucose level during cardiopulmonary bypass, and ensuring adequate perioperative hemostasis may help to avoid pulmonary dysfunction and delayed extubation. Moreover, the PaO2/FiO2 ratio may be a useful predictor of delayed extubation in patients undergoing CABG.

Hemodynamic effects of carbon dioxide insufflation under single-lung ventilation during thoracoscopy.

BACKGROUND The hemodynamic effects of carbon dioxide insufflation under single-lung ventilation were studied in 22 consecutive thoracoscopic harvests of the left internal mammary artery, which was used for minimally invasive coronary artery bypass grafting. METHODS An electrocardiograph, arterial catheter, Swan-Ganz catheter, and transesophageal echocardiograph were used to monitor seven hemodynamic variables. Baseline data were obtained during ventilation of both lungs and the measurements were repeated after the left lung was collapsed and at 5 and 30 minutes after hemithorax insufflation with low-flow (2 to 3 L/minute) carbon dioxide gas was begun. The intrapleural pressure was maintained at 8 to 10 mm Hg. RESULTS Thoracoscopic harvest of the internal mammary artery was completed in all cases with a mean insufflation time of 44+/-12 minutes. There were no significant changes in the mean arterial pressure, heart rate, cardiac index, and left ventricular ejection fraction throughout the procedure, whereas the central venous pressure, mean pulmonary arterial pressure, and pulmonary capillary wedge pressure (p < 0.05 for each variable) during insufflation. CONCLUSIONS Low-flow carbon dioxide insufflation into the left hemithorax with an intrapleural pressure of 8 to 10 mm Hg under selective right-lung ventilation does not compromise the human heart with normal to moderately depressed function and can be an efficacious adjunct in specific thoracoscopic procedures.

Tuberculous Pseudoaneurysm of the Thoracic Aorta

Tuberculous pseudoaneurysm has been reported to be a fatal, but rare complication of tuberculosis. We report a case of a 68-year-old man who underwent successful surgical treatment for a tuberculous pseudoaneurysm of the thoracic aorta with bronchial communication, and review previous reports of patients who also underwent operation for similar lesions, focusing especially on the pathway of infection to the aorta.

Nonreentrant supraventricular tachycardia due to double ventricular response via dual atrioventricular nodal pathways

Narrow and wide QRS tachycardias associated with various rhythm disturbances were recognized during 24-hour ambulatory eletrocardiographic monitoring in a 65-year-old man with coronary artery disease. Laddergram analysis revealed the presence of dual atrioventricular nodal pathways. Non-reentrant supraventricular tachycardia due to simultaneous fast and slow conduction through the dual atrioventricular nodal pathways was confirmed by electrophysiologic study. The atrial rate determined the occurrence of simultaneous conduction, and extrastimulation failed to induce a double ventricular response. Enhanced vagal activity was thought to play a critical role in provoking this phenomenon. Radiofrequency catheter ablation of the slow pathway eliminated the arrhythmias.

Sinus node function after mitral valve surgery via the transseptal superior approach.

OBJECTIVE The transseptal superior approach can offer an excellent view of the mitral valve but the incision almost always transects the sinus node artery. The purpose of this study was to evaluate the sinus node function after mitral operation by this approach. PATIENTS AND METHODS We reviewed the electrocardiograms of 76 patients who underwent mitral valve operations either via transseptal superior approach or via right lateral atriotomy. Nine patients who maintained the sinus rhythm for more than one year after surgery via the transseptal superior approach were selected for electrophysiological study to evaluate the sinus node function. RESULTS AND CONCLUSIONS Postoperative electrocardiographic and electrophysiological studies revealed that the sinus node function after the transseptal superior approach was relatively well maintained for more than one year after the operation. The influence of the transseptal superior approach on the sinus node function in the mid-term postoperative period was apparently mild and did not cause a serious problem. However, some of the patients did show abnormal data in terms of sino-atrial conduction time and intrinsic heart rate. Therefore, further follow-up of the sinus node function is necessary in patients who underwent mitral surgery through the transseptal superior approach.

Successful management of massive pulmonary tumor embolism from renal cell carcinoma

Renal cell carcinoma occasionally invades the inferior vena cava and rarely extends to the right atrium. However, despite the frequency of venous extension, it is unusual to recognize patients with massive pulmonary tumor embolus clinically. We describe a 60-year-old man who underwent pulmonary tumor embolectomy using cardiopulmonary bypass combined with profound hypothermia and intermittent low-flow perfusion. The patient is currently alive and well without implantation metastasis 6 months after the operation.

Atrial ablation with an IRK-151 infrared coagulator

BACKGROUND The purpose of this study was to develop a method of atrial ablation. In the IRK-151 infrared coagulator, light from a tungsten-halogen lamp is focused into a quartz rod. The distal exit plane is connected to a tip made of sapphire to allow linear ablation. METHODS Thirty-six lesions were created in 9 mongrel dogs. The beating ventricular myocardium was ablated from the epicardium. In each dog, 4 lesions were created by using the following durations of application: 3, 9, 15, and 21 seconds. After the ablation, the myocardium was fixed and stained. A linear lesion on the beating right atrial free wall was created. Before and after the ablation, epicardial plaque-electrode mapping was performed. Three months after ablation, remapping was performed. RESULTS The ablated myocardium had well-demarcated necrosis without carbonization or vaporization. The maximum depth was 10.3 +/- 0.8 mm. The conducting pathway was blocked. The block, once made, continued for 3 months. CONCLUSIONS The IRK-151 produces well-demarcated lesions that were deep enough for atrial ablation to block the conducting pathway.

Indication and Perioperative Management for Cardiac Surgery in Patients With Liver Cirrhosis : Our Experience With 3 Patients

Three patients with noncardiac Child A cirrhosis underwent cardiac surgery. All survived surgery, but 2 died during follow-up periods. A 61-year-old woman who underwent successful double valve replacement died of diabetic coma and severe acidosis due to intestinal necrosis 18 months later. A 57-year-old woman who underwent successful mitral valve replacement died of liver failure induced by heart failure 9 years later. A 45-year-old man who underwent coronary artery bypass grafting is doing well 18 months after discharge. Proper perioperative management, including high-flow cardiopulmonary bypass, pharmacological and mechanical circulatory support, and mechanical respiratory support prevented further, potentially lethal, hepatic dysfunction, leading to good early surgical results. We concluded that patients with Child A cirrhosis could tolerate cardiac surgery. Subsequent surgical results, however, were unsatisfactory, and more careful follow-up is necessary to obtain better late results.