The effect of pulsatile perfusion on cerebral blood flow during profound hypothermia with total circulatory arrest

In 39 mongrel dogs, regional cerebral blood flow was measured during pulsatile and nonpulsatile deep hypothermic cardiopulmonary bypass with total circulatory arrest. Total circulatory arrest was performed at 20 degrees C cerebral temperature for 40 minutes in 15 dogs, 60 minutes in 12 dogs, and 80 minutes in 12 dogs. Cerebral blood flow in both groups decreased as cerebral temperature fell and there was no significant difference in cerebral blood flow between the two groups during the cooling period. After circulatory arrest for 40 minutes, as cerebral temperature increased to 35 degrees C, cerebral blood flow in both groups recovered to values as high as the respective initial values, which were measured just after the beginning of cardiopulmonary bypass for cooling (102.5% +/- 10.2% in the pulsatile group and 97.2% +/- 12.6% in the nonpulsatile group). After circulatory arrest for 60 minutes, cerebral blood flow in the pulsatile group increased to 141.8% +/- 16.1% of its initial value when the cerebral temperature became 35 degrees C, but it remained significantly lower (64.5% +/- 9.2%) in the nonpulsatile group (p < 0.01). After circulatory arrest for 80 minutes, cerebral blood flow in both groups remained lower than the respective initial values. These results suggest that pulsatile perfusion maintains cerebral blood flow even during profound hypothermia and that it may protect the brain from ischemic and hypoxic damage caused by profound hypothermia and total circulatory arrest in cardiac operations.

Bilateral main bronchial compression caused by the ductal ligament

Several authors have reported cases of respiratory distress resulting from bronchial compression due to a hypertensive pulmonary artery in the setting of a large left-to-right shunt. However, respiratory distress due to bilateral main bronchial compression due to an enlarged pulmonary artery suspended posteriorly by the ductal ligament following repair of a ventricular septal defect is extremely rare. In this report, we advocate the necessity of dividing the ductal ligament in some patients with large left-to-right shunts when there are episodes of idiopathic respiratory distress before operation.

Disruption of the expanded polytetrafluoroethylene (EPTFE) graft of axillofemoral by-pass

The rupture of the artificial vascular graft is a rare complication. The disruption of the expanded polytetrafluoroethylene (EPTFE) graft has never been reported. The present report describes a patient who suffered the disruption of an EPTFE graft five years after a right axillofemoral by-pass.

[Experimental studies of pulsatile retrograde cerebral perfusion]

This study was investigated for the effects of pulsatile flow on retrograde cerebral perfusion under profound hypothermic circulatory arrest. Fifteen adult mongrel dogs were placed cardiopulmonary bypass and induced profound hypothermia of 20 degrees C at nasopharyngeal temperature. Five dogs were performed non-pulsatile retrograde cerebral perfusion (NP-RCP) and 5 were pulsatile retrograde cerebral perfusion (P-RCP) for 60 minutes each group. The rest of 5 dogs were performed hypothermic circulatory arrest (HCA) without any circulatory assist. Retrograde cerebral perfusion flow rate was regulated to maintain an external jugular vein pressure of 20 mmHg by infusing oxygenated blood by way of bilateral maxillary vein. Regional cerebral blood flow (rCBF), cerebrospinal fluid pressure (CSFP), adenosine triphosphate (ATP) concentration of cerebral tissue, and water content of cerebral tissue were measured. The rCBF were no statistical difference between the two groups. CSFP and ATP concentration in both of NP-RCP and P-RCP were significantly higher than those of HCA. Water content of cerebral tissue in P-RCP were significantly lower than those of NP-RCP. We concluded that retrograde cerebral perfusion for 60 minutes protects the brain as the assistances of circulatory arrest and retrograde cerebral perfusion with pulsatile flow has the possibility to control brain edema as compared with non-pulsatile flow in dogs.

Cerebral metabolism and effects of pulsatile flow during retrograde cerebral perfusion

We evaluated cerebral metabolism during retrograde cerebral perfusion (RCP) and circulatory arrest under profound hypothermia, and also investigated the effect of pulsatile flow on RCP. Eighteen adult mongrel dogs were placed on cardiopulmonary bypass and were cooled to a nasopharyngeal temperature of 20 degrees C. At this temperature, hypothermic circulatory arrest (HCA; n = 6), non-pulsatile RCP (NP-RCP; n = 6), and pulsatile RCP (P-RCP; n = 6) were performed for 60 minutes. Retrograde cerebral perfusion was performed via the bilateral internal maxillary veins, and retrograde flow rate was regulated to maintain a mean perfusion pressure of 20 mmHg in the external jugular vein. During RCP, the temperature was maintained in a narrow range, oxygen consumption and carbon dioxide excretion could be observed, the excess lactate was maintained at a negative value, and cerebral tissue ATP concentration was significantly higher than in the HCA group. The cerebral tissue water content was significantly lower in the P-RCP group than in the NP-RCP group. These findings suggest that hypothermia of the central nervous system, the supply of oxygen, the excretion of metabolites, aerobic metabolism, and the cerebral ATP level were maintained by RCP. In conclusion, RCP may possibly provide adequate metabolic support for the brain during total circulatory arrest, and pulsatile flow appears to reduce cerebral edema when compared with non-pulsatile flow in dogs.

Surgical treatment of the Wolff-Parkinson-White syndrome in children

From 1986 to 1989, seven children ranging in age from 5 months to 16 years underwent surgical treatment for the Wolff-Parkinson-White syndrome at the Shiga University of Medical Science. None of the patients had any other associated congenital heart disease. There was a right free wall accessory pathway in four patients and a left free wall accessory pathway in three. Surgical ablation of these accessory pathways was performed on eight occasions, using the endocardial approach three times and the epicardial approach five. All the children are alive and none has since had episodes of tachycardia. Only one patient had a recurrent delta wave, which was noted 18 months after the operation. Surgical ablation of the accessory pathway for the Wolff-Parkinson-White syndrome can be performed safely, even in infants and children; it is concluded that this useful procedure is capable of improving a patient's quality of life.

Acute extensive necrosis of the visceral organs after repair of a ruptured thoracic aortic aneurysm

A 47-year-old woman was admitted to our hospital for repair of a ruptured thoracic aortic aneurysm. Her post-operative course was uneventful, but she had persistent complaints of anorexia and general fatigue that failed to improve. Thirty-one days after surgery, she complained of severe abdominal pain. Abdominal computed tomography (CT) and X-ray revealed extensive necrosis of the visceral organs. She underwent emergency abdominal exploration and was found to have necrosis of the liver, gallbladder, stomach, entire small bowel and colon. The extensive necrosis made resection of the involved organs unfeasible. The patient died one day after exploratory laparotomy.

[Experimental studies on retrograde cerebral perfusion: efficacy of clamping of the venous blood flow through IVC cannula]

Retrograde cerebral perfusion (RCP) is used to prolong the safe period of circulatory arrest under profound hypothermia. However, this technique now varies in some maneuvers at different institutions. This study investigated the effects on cerebral metabolism of clamping blood flow through the IVC cannula during RCP using fourteen adult mongrel dogs. During circulatory arrest, RCP by way of the bilateral internal maxillary vein was performed. In seven dogs, blood flow was drained through IVC cannula (IVC-drained group) and in the other seven dogs, the blood flow was clamped during RCP (IVC-clamped group). During RCP, the percent of returned blood volume, oxygen consumption, exudation of carbon-dioxide, and oxygen saturation of the returned blood were significantly higher in the IVC-clamped group than in the IVC-drained group, and the concentration of serum CK-BB in the IVC-clamp group was significantly lower than in the IVC-drained group. However, there was no statistical difference between the two groups concerning the regional cerebral blood flow or water content of the cerebral tissue. Concerning about these results, a part of perfused blood passed through not only the extra cranial veno-venous connection but also the intra cranial veno-capillary-venous connection. We concluded that clamping of the venous blood flow through the IVC cannula during RCP is a more protective procedure for cerebral tissue.

[Removal of infected transvenous electrodes requiring cardiopulmonary bypass or extraction sheath]

Infection of four transvenous pacemaker electrodes were experienced in three patients and removed them using different techniques. The first patient had two infected electrodes. One was removed by direct traction and the other required cardiopulmonary bypass for its removal. In the second patient, one electrode was removed using a new extraction system called 'Lead Removal Kit' without thoracotomy. In the third patient, the kit was used during cardiopulmonary bypass. All these patients survived and none had recurrent infection. Our experiences proved that this Lead Removal Kit can minimize the risks for the removal of the infected pacemaker electrodes.

A computer simulation of the plasma leakage through a vascular prosthesis made of expanded polytetrafluoroethylene

We explored the blood-retaining mechanism of a vascular prosthesis made of expanded polytetrafluoroethylene through analysis of its structure and physicochemical properties. Plasma leakage through this vascular prosthesis was simulated by computer to explore its etiology. These examinations disclosed that leakage is dependent upon the inner pressure and the density of fibers. In other words, the study revealed that the mean distance between fibers constituting the wall of the expanded polytetrafluoroethylene vascular prosthesis is increased by tension (that is, inner pressure), resulting in an increased probability of leakage. It was additionally found that a thin membrane is formed on the polytetrafluoroethylene surface if blood in contact with the surface is dried. This membrane was found to reduce the water-repelling property of polytetrafluoroethylene and to make it impossible to preserve the inter-fiber liquid surface, thus causing leakage through the expanded polytetrafluoroethylene vascular prosthesis.

Physicochemical stability of phenobarbital polymorphs at various levels of humidity and temperature

The physicochemical stability of six phenobarbital modifications [forms A, B, C (monohydrate), D (dioxane solvate), E (hemihydrate), and F] at various levels of humidity and temperature were measured using X-ray diffractometry and differential scanning calorimetry. Form D was identified as a new crystalline form (dioxane solvate). Polymorphic transformations of the modifications were investigated by the Kissinger method under nonisothermal conditions. Change of polymorphic content of phenobarbital modifications under various humidity levels at 45 degrees C was evaluated by X-ray powder diffraction. The polymorphic stability under isothermal conditions was estimated kinetically, based upon the Jander equation. Forms A, B, and F were stable at 0 and 75% RH and 45 degrees C for 3 months. On the contrary, forms C, D, and E transformed during storage. The transformation rates of form D were larger than that of forms C and E.

Hygroscopic stability and dissolution properties of spray-dried solid dispersions of furosemide with Eudragit

Spray-dried solid dispersions of furosemide-Eudragit RS100 and RL100 (ethyl methacrylate chlorotrimethylammoniumethyl methacrylate copolymer) were studied to determine their stability at 45 degrees C and 0, 44, and 75% relative humidity and their dissolution characteristics. The crystallization rates of the solid dispersions were measured by X-ray powder diffractometry and calculated on the basis of the Jander equation to estimate physicochemical stability in the presence of water vapor. The stability of the solid dispersion depended on the kind of acrylic resins and the drug content. The solid dispersion with a drug: Eudragit RL100 ratio of 1:3 was the most stable at 75% relative humidity. The dissolution profiles of the solid dispersions were measured in a pH 6.8 buffer at 37 degrees C. The equilibrium drug concentration of the solid dispersions were estimated from the dissolution profiles after 24 h. The equilibrium drug concentration decreased with an increasing Eudragit quaternary ammonium group: furosemide molar ratio. The equilibrium drug concentrations of the solid dispersions with > 0.3 mol of the quaternary ammonium group were approximately 0. Thus, the drug was completely adsorbed on Eudragit.

[Coronary artery bypass grafting for a patient with hypothyroidism--a case report]

A 59-year-old female who had been treated for hypothyroidism was admitted with angina pectoris and underwent aorto-coronary bypass grafting. On closing of the sternum, there was unexpected bleeding from the suture line between the vein graft and the ascending aorta. Histological examination of the aortic wall revealed sparsity and disruption of elastic fibers and deposition of mucopolysaccharide without any findings of atheromatous change. It is concluded that hypothyroidism can cause histological change of the aortic wall and that surgical procedures involving the aortic wall in patient with hypothyroidism should be avoided if possible.

[Left atrial myxoma with production of interleukin 6]

A surgically treated case of left atrial myxoma is reported. A 66-year-old man with a history of cough and orthpnea had an echocardiographic and an MRI diagnosis of left atrial myxoma. He had the constitutional signs of myxoma including acceleration of E.S.R., positive CRP, hyperimmunoglobulinemia, loss of body weight, and so on, in addition to the symptoms of heart failure. Cardiac surgery was performed on him under extracorporeal circulation on June 12, 1990. A large myxoma with a diameter of 6.0 cm x 4.8 cm that was adhering to the fossa ovalis with a stalk was resected. Afterwards the symptoms of both heart failure and the constitutional signs disappeared, and the postoperative course was uneventful. Studies of the excised specimen demonstrated that this tumor produced Interleukin (IL-6). After operation the level of the serum IL-6 that was high before operation was normalized. This suggests that the symptoms and the laboratory results pointing to an autoimmune disease were due to the IL-6 produced from the cardiac myxoma. This is the first report that the localization of the IL-6 in the left atrial myxoma is demonstrated with immunohistochemical stain.

[Effect of prostaglandin E1 treatment on peripheral circulation during extracorporeal circulation--with special reference to its influence on body temperature recovery]

In patients undergoing open heart surgery, we assessed the effect of prostaglandin E1 (PGE1) treatment, 0.1 micrograms/min/kg dosage, during extracorporeal circulation. This treatment resulted in a marked perfusion pressure reduction. As a result, PGE1-treated group showed less urine volume than untreated control group. However, the degree of urine volume reduction relative to the decrease in blood pressure was less in PGE1-treated group than in untreated control group, suggesting a diuretic action of PGE1. We infer from these results that renal blood flow was maintained even after PGE1-induced intense perfusion pressure reduction, allowing for avoidance of renal impairment during extracorporeal circulation. In PGE1-treated adults, recovery of rectal temperature after hypothermic extracorporeal circulation was poorer but that of muscle temperature was better than in untreated adults. This phenomenon can be interpreted as representing improvement of blood-mediated heat transfer from deep regions of trunk to muscles and superficial skin due to PGE1-induced improvement of peripheral circulation. The ameliorative effect of PGE1 on peripheral circulation during extracorporeal circulation was further confirmed by the fact that the amount of NaHCO3 required for correction of metabolic acidosis was significantly lower in PGE1-treated group than in untreated control group. These results indicate that PGE1 treatment during extracorporeal circulation makes body temperature control easier, favorably affects postoperative body temperature recovery and improves peripheral tissue metabolism.

[Complete resection of thymic carcinoma supported by cardiopulmonary bypass]

We would like to report on a case of thymic carcinoma that could be completely resected supported by extracorporeal circulation. A 53-year-old female complaining of severe coughing and hoarseness was admitted to our hospital. Her chest X-ray film revealed an abnormal shadow in the upper mediastinum and an elevation of the left diaphragm. Chest CT and MRI showed an anterior mediastinal mass that invaded the main pulmonary artery. The preoperative histological diagnosis of thymoma was made by mediastinoscopic specimen. After 50 Gy irradiation, surgery was performed. During the operation, after resection of the left brachiocephalic vein and a part of the upper lobe of the left lung, the tumor was detached from the wall of the aorta and resected with the invaded part of the pulmonary artery supported by cardiopulmonary bypass. Reconstruction of the pulmonary wall defect was accomplished with Xenomedica. The final pathological diagnosis was thymic adenosquamous carcinoma. The postoperative course has been uneventful 24 months after surgery. Extracorporeal circulation is a useful technique in operations involving malignant diseases when complete resection is able to be accomplished.

[Minor strut fracture of the Björk-Shiley mitral valve]

In May, 1982, a 49-year-old man underwent mitral valve replacement (MVR) in our hospital with a 31 mm Björk-Shiley prosthesis for mitral regurgitation. He had been doing well until his episode of palpitation and dyspnea of sudden onset, and was transferred to our ICU with severe cardiogenic shock in Aug, 1986. Chest X-ray film revealed pulmonary edema and breakage of the valve with migration of the disc and the minor strut of the prosthesis. He was operated upon 5 hours after the onset of his complaints. The minor strut was removed from the left upper pulmonary vein and mitral valve re-replacement was done with a 29 mm Björk-Shiley Monostrut valve. The disc which had dislocated into the abdominal aorta was also recovered on the twenty-third post operative day. His postoperative course was uneventful. Immediate diagnosis and subsequent re-operation is absolute indication for rescue from acute cardiac failure due to mechanical failure of any prosthetic valve.

[A case report of ventricular septal defect accompanied by winded and elongated malformation of the aortic arch]

A three-year-old boy, surgically treated for a ventricular septal defect, had a winded and elongated aortic arch between the left common carotid artery and the left subclavian artery. Angiography revealed that the arch was positioned more caudalward than normally, and that it was in contact with the left pulmonary artery at a point near the central portion of the arch (i.e., near the position of the ductus arteriosus). The embryological cause of this malformation was speculated. It seemed unlikely that malformations was caused by involution, abnormal growth, etc., of the components of the great vessels in the coursed of embryonic development, but rather to have been caused by an abnormal elongation of the artery at the fourth arch and of the ventral artery between the 6th and 7th intersegmental artery, which had occurred after normal embryonic development. Under extracorporeal circulation, where blood was returned to the patient via the femoral artery, the patient underwent open heart surgery to close the ventricular septal defect. Pressure monitoring during the operation revealed no pressure loss in the winded and elongated portion of the artery; hence, the malformation seemed to cause no hemodynamic problems at present. Considering that the patient is only three years old and that the aorta will continue to grow, we have decided to refrain from any surgical treatment of the winded and alongated part of the aorta for the time being. However, the patient might develop aortic aneurysm in the future because of the relative coactation of the aorta and the insufficient mechanical strength of the winded and elongated area.(ABSTRACT TRUNCATED AT 250 WORDS)

[Re-operation for WPW syndrome due to recurrence of tachycardial attack]

A thirteen-year-old girl was admitted to our hospital because of tachycardial attack. Twelve years ago, she was diagnosed as WPW syndrome and division of accessory conduction pathway was performed at the other hospital, and it was described that the accessory pathway was located on the right lateral wall. ECG showed no delta wave nor PSVT postoperatively. But 12 years later, delta wave and PSVT reappeared. Operative treatment for recurrent tachycardial attacks was performed. Intraoperative pacing study revealed the right posterior-septal accessory pathway. It was divided and cryoablated. This paper reports an additional operation for the second accessory pathway of WPW syndrome.

[A clinical experience of signs of compression in the neighboring organs after operation with Carpentier's method in dissecting aneurysm of the aorta]

A patient with a DeBakey IIIb type dissecting aneurysm of the aorta was treated with Carpentier's method. But after surgery the thromboexclusion procedure at the pseudo-lumen was insufficient. Fourteen months after surgery the left lung area suddenly became opaque, suggesting the possibility of impending rupture of the aneurysm. Therefore the patient underwent emergency surgery in which another permanent clamp was attached to the peripheral end of the aneurysm. After this operation, the aneurysm became reduced in size and the left lung inflated again, but an aorto-pulmonary fistula was formed 24 days later. After 6 months after second surgery, the patient began to experience dysphagia and dyspnea on exertion. Detailed examinations showed that these symptoms were caused by compression of the esophagus, bronchus and pulmonary artery by the permanent clamp. That is, this clamp, which possibly moved during organic change and size reduction of the aneurysm, seems to have compressed the adjoining organs enough to cause dysfunction. Such a compression of the neighboring organs can be regarded as one of problems originating from Carpentier's method, and shows that the procedure is not problem free yet.

[Experimental study on the mechanism of serum leakage from expanded polytetrafluoroethylene (EPTFE) vascular prosthesis]

Even in recent years, the Blalock-Taussig (B-T) shunt operation has been carried out in order to increase pulmonary blood flow in patients of low pulmonary flow congenital heart disease. In such a case, a modified B-T shunt using an EPTFE vascular prosthesis would be employed in order to prevent blood flow obstruction in the upper extremity, and occasionally serum leakage from EPTFE vascular prosthesis is a complication. This has often troubled cardiovascular surgeons the world over, and we attempted to elucidate the mechanism of serum leakage and to discover how to prevent the situation from occurring. Using scanning electron microscopy, the structure of EPTFE vascular prosthesis was found to consist of an average of 0.5 micro meter polytetrafluoroethylene (PTFE) fibers arranged in parallel 5.0 micro meters from each other. The reason why serum does not usually leak from these widely spaced fibers is due to the presence of a repellent force derived from the surface tension and the contact angle between the solid surface of PTFE and the liquid. When the contact angle is over 90 degrees, the repellent force is in effect, while when it is below 90 degrees, this force is decreased. The surface tension and contact angle of physiological saline on the surface of PTFE showed values of 71.6 dyn/cm and 114.0 degrees, respectively, while demonstrating a strong repellent force. On the other hand, the surface tension of heparinized blood on the surface of the PTFE was 56.5 dyn/cm and the contact angle was 90.6 degrees. Thus, heparinized blood was assumed to act on the surface of the PTFE with a weak repellent force and for that reason had a tendency to easily leak from the EPTFE vascular prosthesis. When the surface of the PTFE was in contact with blood, blood protein was fixed to the surface of the PTFE and the contact angle of blood was thereby decreased. When the inner pressure of the vascular prosthesis was increased, the wall was stretched easily in a circumferential direction but with great difficulty in a longitudinal direction. With the PTFE stretched and released repeatedly, the expanded circumference was enlarged progressively due to the plastic character of the PTFE and because the spaces between the PTFE fibers were widened. In order to examine the relationship between the space between fibers and the critical pressure leading to serum leakage, computer simulation was carried out and the results showed a reversed linear correlation between the density of the fibers and the minimal pressures responsible for serum leakage.(ABSTRACT TRUNCATED AT 400 WORDS)