Fumihiko Murakami

Body temperature influences regional tissue blood flow during retrograde cerebral perfusion

OBJECTIVE This study compared the cerebral microcirculation during retrograde cerebral perfusion with that during antegrade cardiopulmonary bypass under normothermic and hypothermic conditions. METHODS Brain tissue blood flow was measured with the hydrogen-clearance and colored microsphere (15 and 50 microns) methods during antegrade cardiopulmonary bypass and retrograde cerebral perfusion. Measurements were performed during normothermia (37 degrees C), moderate hypothermia (28 degrees C) and deep hypothermia (20 degrees C) in groups of mongrel dogs (n = 8). RESULTS During antegrade cardiopulmonary bypass, the microsphere method showed a significant decrease in cerebral blood flow as body temperature decreased (40.1 +/- 20.8 ml/min/100 gm at 37 degrees C, 16.2 +/- 18.0 ml/min/100 gm at 20 degrees C with 50 microns microspheres) At 20 degrees C, the cerebral blood flow measured with the 15 microns microspheres was significantly lower than that assessed with the hydrogen-clearance method (11.3 +/- 7.0 vs 24.8 +/- 7.0 ml/min/100 gm). During retrograde cerebral perfusion, the microsphere method also showed a significant decrease in cerebral blood flow with cooling. At 37 degrees C, the cerebral blood flow measured with the 15 microns microspheres (0.8 +/- 0.7 ml/min/100 gm) was significantly lower than that assessed with the hydrogen-clearance method (10.1 +/- 3.5 ml/min/100 gm). At both 28 degrees and 20 degrees C, the hydrogen-clearance method showed significantly higher cerebral blood flow (10.1 +/- 5.8 and 8.2 +/- 3.7 ml/min/100 gm) than did the 50 microns microspheres (1.8 +/- 0.6 and 1.0 +/- 0.8 ml/min/100 gm) and 15 microns microspheres (0.23 +/- 0.14 and 0.18 +/- 0.15 ml/min/100 gm). CONCLUSION (1) Cerebral blood flow that shunts to capillaries is increased during antegrade cardiopulmonary bypass under deep hypothermia. (2) During retrograde perfusion, the majority of the blood flow shunts away from brain capillaries, even under normothermic conditions, and blood flow through large venoarterial shunts increases as body temperature decreases. Although the cerebral microcirculation during retrograde perfusion is decreased, retrograde perfusion provides some degree of oxygenation to the body.

Continuous retrograde cerebral perfusion for protection of the brain during aortic arch surgery.

Hypothermic circulatory arrest and selective cerebral perfusion for aortic arch surgery have been reported, but these procedures are of limited duration, require hazardous and complicated techniques and can cause clamp injury. Continuous retrograde cerebral perfusion (CRCP) is a new and simple technique for the protection of the brain during hypothermic circulatory arrest. We applied CRCP in 26 patients who underwent aortic arch surgery. Continuous retrograde cerebral perfusion was performed with a mean blood flow of 383 +/- 176, range 120-800, ml/min. The mean duration of CRCP was 63 +/- 15, range 32-92, min with the superior vena cava pressure at 15-42 mm Hg. No neurologic deficit was observed in 20 patients (90%) and only minor deficits in 2 out of the 22 cases without severe postoperative complications, allowing evaluation of the effectiveness of CRCP. Four patients had other severe complications, and the effectiveness of the method could not be evaluated. Continuous retrograde cerebral perfusion can be an excellent and safe technique which avoids clamp injury during aortic arch surgery.

Omental Transfer as a Method of Preventing Residual Persistent Subcutaneous Infection After Mediastinitis

Currently, poststernotomy mediastinitis frequently is being treated by debridement and immediate closure with omental drainage. This method is useful, but subcutaneous infection occasionally occurs. Divided omental transfer to the presternal space may be helpful in preventing this complication.

Nafamostat mesilate reduces blood-foreign surface reactions similar to biocompatible materials

BACKGROUND Nafamostat mesilate (FUT-175) is a synthetic serine protease inhibitor that inactivates coagulation, fibrinolysis, and platelet aggregation. Nafamostat mesilate may suppress the blood-foreign surface reaction similar to biocompatible materials by blocking factor XIIa. METHODS We performed an in vitro study of cardiopulmonary bypass (CPB) with fresh human blood among the following three groups: standard CPB sets (C), biocompatible CPB sets (B), and standard CPB sets with FUT-175 (10 mg/L) (F). A clinical study using these same CPB groups also was performed in 45 patients undergoing aortocoronary bypass operations (15 patients each). We injected FUT-175 at 40 mg/h during CPB. RESULTS In the in vitro study, both groups B and F showed significantly lower levels of coagulation factors, thrombin-antithrombin III complex, fibrinopeptide A, beta-thromboglobulin, complement C3a, granulocyte elastase, and free hemoglobin than group C at the conclusion of the study. Thrombin-antithrombin III complex and free hemoglobin in group F also were lower than in group B. The platelet count remained at a higher level in group F than in the other groups. Separation of bradykinin was suppressed most significantly in group F. In the clinical study, group F also showed significantly lower levels of alpha 2-plasmin inhibitor plasmin complex and C3a than both groups C and B. There were minimal levels of free hemoglobin in group F. CONCLUSIONS Nafamostat mesilate may contribute major beneficial effects toward conservation of blood during CPB and prevention of coagulopathy after CPB.

Rupture of the innominate artery following tracheostomy: Report of a case

A 23-year-old man underwent a tracheostomy. A massive hemorrhage from the tracheostomy site occurred 50 days later. An emergency operation was immediately performed and an erosion was noted on the innominate artery. The artery was divided and the hemorrhage was successfully stopped.

Mitral valve replacement via right thoracotomy after coronary arterial grafting

Mitral valve replacement was performed through a right thoracotomy using femorofemoral bypass under profound systemic hypothermia in a 62-year-old man who had undergone coronary artery bypass grafting using both internal thoracic arteries. The right thoracotomy approach minimizes the risk of injury to the arterial grafts, and deep hypothermia obviates the need to interrupt the grafts to administer cardioplegia. This technique provides excellent exposure of the mitral valve while minimizing the operative risk.

Sandwich repair with two sheets of equine pericardial patch for acute posterior post-infarction ventricular septal defect.

A 74-year-old man, who had posterior post-infarction ventricular septal defect, was treated successfully by early surgical repair with a sandwich technique involving two sheets of equine pericardial patch. In this technique the ventricular septal defect (VSD) was exposed through a trans-infarction approach. The inside patch covered the VSD and ventriculotomy from the inside. The outside patch generously covered the infarcted myocardium. The two patches completely sandwiched the infarcted myocardium including the VSD and ventriculotomy with eighteen interrupted sutures. This technique ensures strong fixation of the VSD, reducing the risk of bleeding and recurrence of VSD, and also maintains the proper shape and size of the left ventricle without the danger of ventricular aneurysm formation.

EMERGENCY AORTIC ARCH REPLACEMENT IN A PATIENT WITH IDIOPATHIC THROMBOCYTOPENIC PURPURA

We herein report the case of a 56-year-old man with idiopathic thrombocytopenic purpura who required an emergency aortic arch replacement. Intraoperatively, hemostasis was achieved using platelet transfusions. Postoperatively, the use of high-dose γ-globulin therapy was able to maintain an adequate platelet count and good hemostasis.

Non-mycotic Pseudoaneurysm in the Ascending Aorta Following Cardiac Surgery

Cannulation of the ascending aorta is the recognized method to achieve arterial return during cardiopulmonary bypass. Mediastinal infection after cardiac surgery can cause disruption at the point of insertion, and give rise to a pseudoaneurysm in the ascending aorta. Although rare, a pseudoaneurysm can occur without clear evidence of infection. Here we report two cases that received aortic valve replacement and that developed ascending aortic aneurysms after surgery. Based on our clinical findings, these aneurysms were related to the arterial cannulation into the aorta and not to any infection.

Protective effect of nisoldipine on myocardial ischemia during coronary bypass surgery

BACKGROUND Nisoldipine, a calcium antagonist, was assessed for myocardial protection and the prevention of reperfusion injury in patients undergoing CABG. METHODS Of the 34 subjects undergoing CABG in this study, 20 were given nisoldipine orally at 10 mg/day for 2 weeks before surgery (N group) and the other 14 untreated controls (C group). Myocardial protection was conducted via ante-grade cold blood cardioplegia at 20-minute intervals. RESULTS Myocardial blood flow was significantly higher in the N group (67.8 +/- 21.8 ml/100 g vs. 47.2 +/- 14.4 ml/100 g, p < 0.05) after cardiopulmonary bypass. Serum interleukin-6 levels were significantly lower in the N group 1 hour after reperfusion (116 +/- 58 vs. 409 +/- 362 pg/ml, p < 0.05), as were serum lactate dehydrogenase levels immediately after surgery (888 +/- 268 vs. 1350 +/- 486 IU/L, p < 0.05). The N Group showed a better left ventricle stroke work index 6 hours after surgery (43 +/- 8 vs. 36 +/- 9 g.m/m2). Dopamine dosage in the N group on postoperative day 1 was lower than in controls (5.3 +/- 1.9 vs. 3.0 +/- 2.4 micrograms/kg/min). CONCLUSIONS Preoperative nisoldipine treatment increased blood flow in the postischemic myocardium and prevented myocardial damage and reperfusion injury to some extent.