Comparative clinical study between retrograde cerebral perfusion and selective cerebral perfusion in surgery for acute type A aortic dissection.

OBJECTIVE: Selection of a brain protection method is a primary concern for aortic arch surgery. We performed a retrospective study to compare the respective advantages and disadvantages of retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in patients who underwent surgery for acute type A aortic dissection. METHODS: The study reviewed 166 patients who underwent surgery at Nagoya University or its eight branch hospitals between January 1990 and August 1996. There were 91 patients who received SCP and 75 patients who underwent RCP. Results for these two groups were compared. RESULTS: There were no significant differences in age, gender, Marfan syndrome rate, DeBakey classification, or emergency operation rate. Rates of various preoperative complications were similar except for aortic valve regurgitation. Arch replacement was performed more often in SCP than in RCP patients (49% vs. 27%, P = 0.0028). There were no significant differences between groups in cardiac ischemic time or visceral organ ischemic time. However, RCP group showed shorter cardio-pulmonary bypass time (297+/-99 vs. 269+/-112 min, P = 0.013) and lower the lowest core temperature (21.6+/-3.1 degrees C vs. 18.7+/-2.1 degrees C, P = 0.0001). SCP duration was longer than RCP duration (103+/-56 vs. 54+/-24 min, P < 0.0001). Despite these differences, RCP patients were not significantly different from SCP patients with regard to any postoperative complication, neurological dysfunction (16 vs. 19%), or operative mortality (all deaths within the hospitalization; 24 vs. 21%). Regarding neurologic dysfunction, there were six cases of coma, six of motor paralysis, two of paraplegia and one of visual loss among SCP patients, and eight cases of coma, three of motor paralysis, and three of convulsion in the RCP group. The incidence of motor paralysis was higher in the SCP group, while the incidence of coma was higher in the RCP group. CONCLUSIONS: RCP can be performed without clamping or cannulation of the cervical arteries, which is an advantage in reducing the chances of arterial injury or cerebral embolization. RCP is comparable to SCP in terms of clinical outcome.

Effects of proximal ventricular septal pacing on hemodynamics and ventricular activation.

Recently the use of alternate site pacing to improve cardiac function in patients with bradyarrhythmias has increased. In the present study, hemodynamics of right ventricular septal pacing were studied in seven dogs. A bipolar screw-in lead and endocardial lead were placed in the proximal right ventricular septum and right ventricular apex, respectively. The right ventricle was paced from each site. A conductance catheter and Millar catheter were inserted into the left ventricle to determine the left ventricular pressure and the pressure-volume loop. Cardiac output was measured using the thermodilution method. In five of the seven dogs, ventricular activation was documented by isochronal epicardial activation mapping during each pacing mode. Mean arterial pressure and cardiac output during septal pacing were significantly higher than during apical pacing (110 +/- 17 mmHg vs 100 +/- 18 mmHg; 1.00 +/- 0.39 L/min vs 0.89 +/- 0.33 L/min). The positive dp/dt during septal pacing was significantly higher than during apical pacing (2137 +/- 535 mmHg/s vs 1911 +/- 404 mmHg/s). End-systolic elastance during septal pacing was significantly higher compared to apical pacing (13.1 +/- 0.3 mmHg/mL vs 8.9 +/- 4.0 mmHg/mL). The ventricular activation time during septal pacing was significantly shorter than during apical pacing. The epicardial maps generated during septal pacing were similar to those from atrial pacing. We conclude that hemodynamics and interventricular conduction are less disturbed by proximal right ventricular septal pacing than apical pacing in dogs with normal hearts.

A survey of filling methods, intracanal medications, and instrument breakage.

The present survey was conducted to obtain answers to some basic questions regarding the use of intracanal medications, root canal filling methods, and the intracanal breakage of instruments. A letter was sent to 300 endodontists listed in the 1995-1996 membership roster of the American Association of Endodontists. Eighty-five replies were received. Calcium hydroxide as an intracanal medication was used by 91.7% of the responding endodontists. With regard to the root canal filling technique, 52.9% used the lateral condensation method. When intracanal breakage occurred, 95.3% of the respondents informed the patient. The results of this survey provide useful information for the education of undergraduate dental students.

Results of omental flap transposition for deep sternal wound infection after cardiovascular surgery.

OBJECTIVE: Our experience with omental flap transposition in the treatment of deep sternal wound infections is reviewed here with an emphasis on efficacy, risk factors for in-hospital mortality rates, and long-term results. SUMMARY BACKGROUND DATA: Even with improvements in muscle and omental flap transposition, the timing of closure and the surgical strategy are controversial. METHODS: Forty-four consecutive patients with deep sternal wound infections were treated using the omental flap transposition from 1985 through 1994. The strategies included debridement with delayed omental flap transposition or single-stage management, which consisted of debridement of the sternal wound and omental flap transposition. Methicillin-resistant Staphylococcus aureus was cultured from more than 50% of the wounds. A logistic regression analysis was used to identify the predictors of in-hospital death after omental flap transposition. RESULTS: There were seven (16%) in-hospital deaths. Univariate analysis demonstrated that hemodialysis and ventilatory support at the time of omental flap transposition were significantly associated with in-hospital mortality rates (p = 0.0023 and p = 0.0075, respectively). Thirty-seven patients whose wounds healed well were discharged from the hospital. Two patients with cultures positive for methicillin-resistant Staphylococcus aureus had recurrent sternal infections. Patients without positive methicillin-resistant Staphylococcus aureus cultures had good long-term results after reconstructive surgery. CONCLUSIONS: Transposition of an omental flap is a reliable option in the treatment of deep sternal wound infections, unless the patients require ventilatory support or hemodialysis at the time of transposition.

Blood cardioplegia infusion using a recirculation type circuit generates bradykinin in significant amounts during open heart surgery.

The single pass type (SP) of blood cardioplegia is commonly used in North America during open heart surgery. However the recirculation type (RC) of blood cardioplegia is still widely used in other areas including Japan. Infusion blood cardioplegia using the latter technique often decreases the perfusion pressure. To determine the cause for this, blood levels of bradykinin (BK) were measured in cardiopulmonary bypass (CPB) and the 2 types of blood cardioplegic circuits. As the BK levels in the RC cardioplegia (>3,000 pg/ml) rose, the perfusion pressure decreased abruptly with the increase of the BK levels in the CPB circuit. With SP cardioplegia, the BK level was not increased either during cardioplegia (p < 0.009) or CPB (p < 0.009), and the perfusion pressure was not decreased (p < 0.02). We concluded that the SP circuit is superior to the RC one because of the lesser production of BK and thus lesser fluctuation of perfusion pressure.

[Long-term late results of pericardiectomy for constrictive pericarditis].

Twenty-four cases of the constrictive pericarditis were operated on pericardiectomy from 1966 to 1990. One case died because of massive bleeding, LOS, and respiratory failure immediately after the operation. A long-term follow up study was performed up to 27 years (mean 13.1 years) in other cases. Ten cases died during the follow up period (cardiac: 6, non cardiac: 4). Five cases of the cardiac deaths had major complications: tabes dorsalis, chronic respiratory failure, pacemaker implantation, mitral regurgitation, emergency operation at high age (78 years old). The survival rates of 5, 10, and 15 years were 85%, 67%, and 58.2%, respectively (Kaplan-Meier). All of survival cases are now in NYHA I or II class in satisfactory. We concluded that pericardiectomy is a very effective treatment for constrictive pericarditis but a more careful follow up is required especially in cases complicated with other major problems because cardiac function is not so recovered as normal level after surgery due probably to readhesion and fibrotic changes of the myocardium.

The omental flap with skin grafting for treatment of a difficult sternal closure.

A case report of difficult sternal closure is described. Chest closure following cardiac operation in critically ill patients can be a problem. Techniques have been described so that sternal closure can be delayed until the patient is hemodynamically stable and hemostasis has been achieved. However, in some instances, the sternal closure can not be performed because of prolonged cardiopulmonary instability. We describe the use of transposition of an omental flap with skin grafting in a 74-year-old patient with aortic valve stenosis, poor pulmonary function, and a thoracic deformity. This technique enabled incomplete sternal closure which maintained hemodynamic stability.

Histopathological features of canine distemper recently observed in Japan.

Eleven dogs with canine distemper (CD) from the Chubu region of Japan and the Tokyo area were examined. Clinically, respiratory and neurological signs were present in all animals. Histopathologically, all showed characteristic CD lesions of bronchopneumonia and demyelinating encephalitis. However, some differences in gastrointestinal abnormalities were observed. Three out of four dogs from the Chubu region had severe diarrhoea and gastroenteritis, associated with numerous eosinophilic inclusion bodies in the mucosal epithelia. The remaining dog from this area showed vomiting, but not diarrhoea, and also had a number of intraepithelial inclusion bodies in the gastric and intestinal mucosa. In contrast, the seven dogs from the Tokyo area showed neither gastrointestinal symptoms nor intraepithelial inclusions in the stomach or intestine. Immunohistochemical examination for CD virus antigen, however, revealed that these seven dogs had immunoreactive products in the mucosal epithelia, suggesting that the epithelial cells had either a low level of infection with CD virus or were infected with a less cytopathogenic virus. These findings suggest that the dogs in this study were probably affected by two distinct types of CD, in terms of epitheliotropism and cytopathogenic effects on the gastrointestinal tissues.

Alterations in macrophages after exposure to root canal filling materials.

The process of engulfment of overextended root canal filling materials was investigated in rat peritoneal macrophages in vitro. Root canal filling materials tested were Finapec APC, Sealapex, Canals-N, and Canals. The phagocytosis rate of macrophages for the Finapec APC was significantly (p < 0.05) higher than that for other three root canal filling materials. That for Canals was the lowest. About 95% of the cells exposed to Finapec APC were viable at 60 and 120 min. For Canals the percentage was 74% and 63% at 60 and 120 min, respectively. Ruffle formation in macrophages was observed by scanning electron microscopy after exposure to Finapec APC for 60 or 120 min. Many vacuoles were observed in macrophages exposed to Canals for 60 min. It was concluded that the phagocytic rate of macrophages for Canals that showed a strong cytotoxicity was lowest and that the rate for Finapec APC that showed a low cytotoxicity was the highest.

[Influence of recirculation type blood cardioplegia on perfusion pressure in open heart surgery].

Infusion blood cardioplegia often decreases the perfusion pressure during open heart surgery. The blood level of bradykinin (BK) was measured in both the cardiopulmonary bypass (CPB) and blood cardioplegia circuit. Infusion cardioplegia with recirculation type circuit increased the BK level of cardioplegia and the perfusion pressure decreased abruptly with the increase BK level in the CPB circuit. In the case of single pass type circuit the BK level was not increased either in cardioplegia or CPB and perfusion pressure was not decreased. We concluded that the single pass type of cardioplegia circuit is superior to the recirculation type because of less production of BK.

Successful repair of tricuspid regurgitation 46 years after causal blunt trauma.

Tricuspid regurgitation arising from chest trauma 46 years earlier was successfully corrected by valve reconstruction in a 67-year-old man. As the merits of valve repair are well established, it can be advocated for traumatic tricuspid regurgitation, regardless of the time from the causal injury.

[Repair of mitral valve prolapse by resection and sliding plasty].

There have been many techniques applied to the repair of mitral valve prolapse, and the method used in a particular case is usually selected according to the position and extent of the lesion. To simplify and standardize the technique of mitral valve repair, we have adopted the resection, sliding plasty and ring annuloplasty methods since December 1992. Of 10 consecutive surgical cases, 2 involved prolapse of the anterior leaflet, 1 the posteromedial commissural, and 7 the posterior leaflet. One patient with posterior leaflet prolapse required valve replacement due to dehiscence of the plastied site on the 3rd postoperative day, and one died because of sepsis. However, the remaining patients were doing well without mitral regurgitation at a mean of 20 months (range: 8-32) after the operation. The advantages of these techniques include easy adjustment of the height of the leaflet and a good chance of long-term durability, since the affected lesion is resected.

A new device for exposing the circumflex coronary artery.

We have devised a new retractor for use in coronary artery bypass grafting that is made from three woven Teflon tapes. This method allows sufficient counterclockwise rotation of the heart, provides excellent exposure of the posterior and inferior coronary artery systems, and creates a horizontal surgical plane for the circumflex anastomosis.

[Reoperation for complications of mitral valve surgery].

Among the early postoperative complications of mitral valve surgery. Mitral Regurgitation (MR) is one of the most dangerous complications, which has to be diagnosed and to be treated as early as possible. Four reoperations-two of which are of paraprosthetic regurgitation, and two of recurrent MR after mitral valve plasty-are reported. Their clinical courses and transesophageal echocardiographic findings are shown. And the differences their MR has when it is compared with the physiologic MR of the prosthetic valve and with the acceptable MR after mitral valve plasty are described.

Resection of aortic aneurysms without aortic clamp technique with the aid of hypothermic total body retrograde perfusion.

Aneurysms involving either the aortic arch or the proximal descending thoracic aorta in five patients were resected with the aid of profound hypothermic total body retrograde perfusion. Traditional surgical management of the aortic arch and the descending thoracic aorta necessitates clamping of the aorta. However, this technique may be associated with rupture or atheroembolism. Rupture occurring at the clamping site may be difficult to repair. Atheroembolism to the brain compromises the neurologic system, and multiple organ embolism is associated with disseminated intravascular coagulopathy. Atheroembolism in cardiovascular surgery has become increasingly prevalent. It is necessary to prevent clamp injuries and to preserve the function of the vital organs, such as the brain, heart, and liver, during aortic reconstruction. We applied a total body retrograde perfusion technique to operations for aortic aneurysms. Total body retrograde perfusion consists of cerebral protection by continuous perfusion through the superior vena cava, intermittent retrograde coronary perfusion through the coronary sinus, and continuous abdominal visceral perfusion through the inferior vena cava. It can yield a relatively bloodless operating field without the need for aortic clamping. We believe this new adjunct offers excellent results in the surgical treatment of aneurysms of the aortic arch or adjacent structures.

The effects of using a leukocyte removal filter during cold blood cardioplegia.

During myocardial ischemia, neutrophils and platelets exert negative effects on the myocardium. In this study, we used a leukocyte removal filter during cardioplegia, and investigated its effect on myocardial damage during reperfusion by measuring the plasma levels of granulocyte components, platelet components, and cardiac enzymes [creatinine phosphokinase (CK) and creatinine phosphokinase myocardial band (CK-MB)] in 24 patients who underwent cardiopulmonary bypass. The patients were divided into two groups of 12 according to whether or not a filter was placed in the cardioplegic route. Blood samples were drawn directly from the coronary sinus before aortic cross clamping, and at 1, 5, and 15 min after declamping. Group F, which had the filter, showed better cardiac enzyme and lipid peroxidation results than group N, which did not. The results of this study suggest that the application of a filter during cold blood cardioplegia may reduce myocardial damage.

Effects of magnesium on isolated canine coronary arterial tension.

The effects of magnesium on the tension of isolated canine coronary arterial strips were studied. In the solution containing K+ of 20 mEq.l(-1), Ca2+ of 4 mEq.l(-1), and Na+ of 127 mEq.l(-1), the tension was 811 +/- 111 mg with Mg2+ of 1 mEq.l(-1), 494 +/- 135 mg with Mg2+ of 10 mEq.l(-1), 272 +/- 126 mg with Mg2+ of 20 mEq.l(-1), -52 +/- 63 mg with Mg2+ of 30 mEq.l(-1), -69 +/- 80 mg with Mg2+ of 40 mEq.l(-1). In the solution containing K+ of 20 mEq.l(-1), Na+ of 12 mEq.l(-1) and Ca2+ of 0 mEq.l(-1), the tension was 102 +/- 22 mg with Mg2+ of 1 mEq.l(-1), 3 +/- 35 mg with Mg2+ of 10 mEq.l(-1), -49 +/- 33 mg with Mg2+ of 20 mEq.l(-1), -59 +/- 49 mg with Mg2+ of 30 mEq.l(-1), -65 +/- 54 mg with Mg2+ of 40 mEq.l(-1). The data demonstrated that Mg2+ above 30 mEq.l(-1) inhibited the increase in tension caused by Ca2+ and Mg2+ above 20 mEq.l(-1) inhibited the increase in tension caused by low Na+ concentration.