Hajime Ohzeki

Biocompatibility of a silicone-coated polypropylene hollow fiber oxygenator in an in vitro model

BACKGROUND A silicone-coated microporous hollow-fiber membrane oxygenator has been developed to prevent plasma leakage during long-term use. The objective of this study was to evaluate the biocompatibility of the oxygenator. METHODS A silicone-coated oxygenator was compared with an uncoated oxygenator in an in vitro model of cardiopulmonary bypass. Simulated circulation was maintained for 6 h at 37 degrees C. RESULTS Platelet counts decreased significantly (p < 0.05) and leukocyte counts tended to decline; however, the differences between groups were not significant. Concentrations of C3a increased significantly in both groups (p < 0.05), but levels were significantly less in the silicone-coated oxygenator (p = 0.008). In contrast, concentrations of C4a, beta-thromboglobulin, and granulocyte elastase increased significantly (p < 0.05), but the differences between groups were not significant. CONCLUSIONS Silicone coating over a microporous hollow-fiber membrane may improve biocompatibility by reducing C3a activation.

Acute acalculous cholecystitis after cardiovascular surgery.

The development of acute acalculous cholecystitis (AAC) after cardiovascular surgery is an infrequent but devastating complication, the etiology and management of which remains controversial. To evaluate the etiology, treatment, and outcome of patients with AAC, the cases of six patients encountered within an 8-year period who developed AAC after cardiovascular surgery requiring cardiopulmonary bypass (CPB) were reviewed. Atherosclerotic risk factors including diabetes, hyperlipidemia, and smoking were evident in five patients, three of whom had a history of stroke or arteriosclerosis obliterans, while low cardiac output was recognized in three. Percutaneous transhepatic cholecystostomy was performed in five patients, and another required cholecystectomy for peritonitis due to gangrene of the gallbladder. Two patients died of respiratory failure and sepsis after 15 and 82 days of percutaneous drainage, respectively; however, the four survivors had an excellent outcome without any biliary tract disease during a mean follow-up period of 5.3 years. In conclusion, AAC after cardiovascular surgery may result from hypoperfusion of the gallbladder due to various factors including CPB, visceral atherosclerosis, and low cardiac output. We advocate early percutaneous cholecystostomy for patients without peritonitis, while early cholecystectomy is indicated for those with peritonitis.

Development of an endocardioscope for repair of an atrial septal defect in the beating heart

The purpose of this study was to evaluate the possibility of surgical treatment of an atrial septal defect in the beating heart without cardiopulmonary bypass. The first step was to develop an endocardioscope that permitted observation of the inside of the beating heart. To visualize the inside of the beating heart, the tip of the endoscope was covered with a glass adapter. The endocardioscope was inserted through the right atrial appendage in eight beagles. The atrial septum, foramen ovale, coronary sinus, tricuspid valve, and chordae tendineae were identified without hemodynamic derangement. The second step was to attempt to close the foramen ovale with clips or staplers. We were able to close the foramen ovale with these devices, but a safer, easier device is needed. The endocardioscope we developed should prove to be a useful tool for minimally invasive surgical treatment of heart diseases, such as atrial septal defect.

Successful removal of massive cardiac neurilemoma with cardiopulmonary bypass

A 46-year-old woman was referred to our hospital because of cardiac enlargement seen on a chest radiograph. Imaging studies showed a massive intrapericardial tumor with a size of 12x8x7 cm. Tumor dissection included inspection of the inner aspect of the superior vena cava with use of cardiopulmonary bypass, because the mass was tightly adherent to both superior vena cava and right atrium. The pathologic diagnosis was neurilemoma.

“Tail Sign” Associated With Microembolic Signals

BACKGROUND AND PURPOSE Transcranial Doppler ultrasound (TCD) can detect circulating microembolic signals (MES). We focused our attention on tail signs (TS), a signal associated with MES that appeared as a small reversal signal after MES on the high time resolution spectral display. We examined MES and artifacts in an animal study to determine whether TS were specific changes associated with MES and investigated the characteristics of TS in both animal and clinical studies. METHODS In an animal study, adult pigs with venoarterial extracorporeal membrane oxygenation and minimal anticoagulation therapy were used as a model for cerebral embolism. After performing TCD monitoring with a multigated approach, we did an offline analysis to investigate several parameters concerning MES and TS. We also examined TS in patients in a clinical study. RESULTS From a total of 362 MES investigated in the animal study, 72.9% were followed by TS. We could not find any TS associated with artifacts. The time delay between TS and MES was negatively correlated with the velocity of MES. MES almost always appeared first in the proximal channel, whereas TS conversely appeared first in the distal channel. In the clinical study, we were also able to observe TS associated with MES. CONCLUSIONS TS may represent emboli passing down a branch vessel or twisted downstream vessel. TS are specific for MES and can be used as another criterion for MES identification.

Extracorporeal Membrane Oxygenation for Severe Heart Failure After Fontan Operation

A 10-year-old boy with tricuspid atresia and Glenn anastomosis underwent a modified Fontan operation. After the operation, the pressure in the inferior vena cava increased, leading to oliguria and ascites. After the creation of continuity between the superior vena cava and the inferior vena cava to reduce the pressure gradient, there remained an elevated right atrial pressure. Six days of extracorporeal membrane oxygenation effectively stabilized his hemodynamics and organ function and allowed an excellent outcome.

The effect of fibrin glue on inhibition of pericardial adhesions

The effect of fibrin glue on inhibition of pericardial adhesions was tested using 26 beagle dogs. Dacron patches were sutured to the heart and tincture of iodine was applied to promote adhesions. Fibrin glue (3 ml) was sprayed over the patches in 15 dogs (test group), and was not separated in the remaining 11 dogs (control group). All animals in the test group had minimal adhesions between the pericardium and the epicardium or patched region, and an accumulation of gelatinous material was found in the subpericardial space. Marked fibrosis and a poor demarcation of the subpericardial space were found in the control group. The adhesion score and the visibility of coronary anatomy in the test group were significantly better than in the control group. The tension strength in the test group was significantly less than in the control group. We concluded, therefore, that fibrin glue may also be useful as an adhesion inhibitor.

The Influence of a Heparin‐Coated Oxygenator During Cardiopulmonary Bypass on Postoperative Lung Oxygenation Capacity in Pediatric Patients with Congenital Heart Anomalies

Abstract Background: Cardiopulmonary bypass (CPB) causes an inflammatory response and remarkably depresses the oxygenation capacity of the lung in pediatric patients with pulmonary hypertension. Although a heparin‐coated circuit is more biocompatible than an uncoated circuit, the beneficial effect of a heparin‐coated circuit on the postoperative lung function in the pediatric patients remains unknown. Methods: Sixty patients younger than 3‐years‐old undergoing heart operations for ventricular septal defect were divided into three groups: group I = children (n = 11) without pulmonary hypertension who underwent CPB with an uncoated oxygenator; group II = children (n = 32) with pulmonary hypertension who underwent CPB with an uncoated oxygenator; and group III = children (n = 17) with pulmonary hypertension who underwent CPB with a heparin‐coated oxygenator. A respiratory index (RI) was used to assess the oxygenation capacity of the lung. Results: RI in group II was significantly higher than in group I and intubation time in group II was significantly longer than in group I. There was a positive correlation between preoperative pulmonary‐systemic blood pressure ratio and RI at 3 hours post‐CPB. Three and six hours post‐CPB, RI in group III was significantly lower than in group II, but there was no significant difference in RI between both groups at 12 hours post‐CPB. Conclusions: Pulmonary hypertensive pediatric patients were vulnerable to postperfusion lung injury. Beneficial effects of a heparin‐coated oxygenator in a CPB circuit was limited to the early hours post‐CPB and the postoperative clinical course was not modified by the heparin‐coating of a membrane oxygenator.

Left Atrial ball thrombi without mitral valve disease treated by surgical removal

We describe two patients with free-floating left atrial ball thrombi with no evidence of cardiac disease except atrial fibrillation. One patient had experienced an embolic stroke, and the second patient had a history of stroke and peripheral thromboembolism. In each patient, the thrombi, which were not visible on transthoracic echocardiography, were detected by transesophageal echocardiography. Each patient underwent successful surgical removal using cardiopulmonary bypass.

Transapical Aortic Cannulation in Pediatric Patients

We describe transapical aortic cannulation in pediatric patients. This technique may help to establish cardiopulmonary bypass in small children in whom aortic root cannulation is undesirable or not feasible.