Minimally invasive cardiac surgical techniques in the closure of ventricular septal defect: an alternative approach

BACKGROUND

Minimally invasive cardiac surgical techniques recently have been applied in the management of a variety of intracardiac lesions.

METHODS

Fourteen patients (6 boys and 8 girls; age, 8.9 +/- 5.5 years; body weight, 29.0 +/- 13.5 kg) were operated on using minimally invasive cardiac surgical techniques for the closure of a ventricular septal defect (subarterial in 11 patients and perimembranous in 3 patients). The operations were performed through a left anterior minithoracotomy and were guided by video-assisted endoscopic techniques under femorofemoral cardiopulmonary bypass. The myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The right ventricular outflow tract was entered after pericardiotomy was performed.

RESULTS

Closure of the defect (directly in 4 patients and by patch in 10 patients) was performed successfully in all patients. A right ventricular outflow tract obstruction and ruptured sinus of Valsalva aneurysm also were repaired in 1 patient each. The duration of cardiopulmonary bypass was 41 +/- 10 minutes (range, 28 to 100 minutes) and the total operative time was 2.2 +/- 0.8 hours (range, 1.3 to 3.5 hours). All the patients recovered rapidly from their operation and had an uneventful postoperative course. Follow-up (mean, 6.2 months; range, 6 to 9 months) was complete in all patients. There were no late deaths. Transthoracic echocardiographic examination showed no residual shunt and no aortic regurgitation in all patients.

CONCLUSIONS

Our experience demonstrates that minimally invasive cardiac surgical techniques are technically feasible and an alternative option for the repair of a ventricular septal defect.

Minimally invasive approach for coronary artery bypass surgery

Forty-two patients, 33 male and 9 female, aged 35.7 to 81.6 years old (mean 62.7), were operated on for left main and/or triple vessel coronary artery disease by using minimally invasive cardiac surgical techniques. A myocardial infarction had occurred in 26 patients (61.9%). The left ventricular ejection fraction ranged from 17 to 83% (52+/-22). The surgeries were performed through left parasternal minithoracotomy (8 to 12 cm in length) under femoro-femoral or aorto-atrial cardiopulmonary bypass. The myocardium was protected by blood cardioplegic solution with the aorta crossclamped. Under direct vision, average 3.8 distal anastomoses were performed in each patient, with the saphenous vein grafts and the left internal thoracic arterial graft. The aortic crossclamp time was 62 to 137 min (80+/-15). The duration of cardiopulmonary bypass was 88 to 168 min (115+/-24). The postoperative course was uneventful in all patients. Follow-up (1.0 to 5.6 months, mean 2.9) was complete in all patients and there were no late deaths or angina. Coronary angiography of ten patients showed patent grafts. Our experience demonstrates that minimally invasive cardiac surgery during cardioplegic arrest is technically feasible and can be performed in coronary artery disease safely and effectively for complete revascularization.

Cardiac tamponade in Taiwan

We retrospectively reviewed all of the patients who were treated for cardiac tamponade at Linkou Chang Gung Memorial Hospital between January 1991 and December 1995. There were a total of 112 patients (57 males, 55 females) with a mean age of 51 +/- 14 years (53 +/- 15, 49 +/- 13, respectively). Dyspnea was the most common complaint (85%). The mean blood pressure was 129 +/- 24/78 +/- 17 mmHg, and only 8% had a systolic blood pressure of less than 90 mmHg. Sinus tachycardia was the most frequent electrocardiographic finding (72%, 62/86). Diffuse low voltage was noted in 35% (30/86) of the patients and electrical alternans was seen in 17% (15/86). The mean volume of pericardial effusion was 610 +/- 263 ml. Sixty-five percent of the pericardial effusions were bloody, 31% were serosanguineous, 2% were purulent and 2% were chylous. Overall, 54.5% of the patients had malignant diseases. Of the 61 patients who died, 79% had malignancies. Thirty-five (57%) of these 48 patients had lung cancer. The mean survival time from emergent pericardiocentesis was 3.4 months. In conclusion, non-traumatic cardiac tamponade had a poor prognosis because most patients had malignant etiologies. There is still no definitive treatment for recurrent malignant pericardial effusion-induced cardiac tamponade. Percutaneous pericardiocentesis as clinically required may be the most appropriate treatment, since it is questionable whether such subjects should be subjected to the unnecessary pain and suffering associated with an operative procedure, considering their short mean survival time.

Internal iliac artery aneurysmo-rectal fistula associated with multiple aortoiliac aneurysms

Fistular communication between an internal iliac artery aneurysm and rectum presenting as massive lower gastrointestinal tract bleeding is a rare entity in clinical practice. Prompt diagnosis and experienced therapeutic application determine the outcome. Herein we report the successful management of such a complication. A 68-year-old male had multiple aneurysms over the abdominal aorta and bilateral iliac arteries. It was the largest aneurysm arising from the right internal iliac artery which ruptured into the rectum and resulted in massive hematochezia. After extraanatomical bypass with right axillo-femoral and femoro-femoral crossover grafts to restore the circulation to the bilateral lower limbs, the infrarenal abdominal aorta just immediately above the proximal aneurysm was transected and closed as a blind stump. All the aneurysms were included in this resection and as much of the infected aneurysm tissue was debrided as possible. The rectum was exteriorized using Hartmann's procedure. The patient survived the operation and was discharged in good condition.

The role of Src kinase in the potentiation by ethanol of cytokine- and endotoxin-mediated nitric oxide synthase expression in rat hepatocytes

This study demonstrates that exposure of primary rat hepatocytes or mouse BNL Cl.2 liver cell line to ethanol causes potentiation of tumor necrosis factor-alpha (TNF-alpha)- and lipopolysaccharide (LPS)-stimulated nitrite accumulation. The potentiating effect of ethanol (0.02-2 mM) appears to be time and concentration dependent. Consistent with nitrite production, the amount of inducible nitric oxide synthase (iNOS) mRNA and protein is initially detected at 4 hr after treatment with TNF-alpha/LPS/ethanol. Furthermore, the capability of these agents to induce iNOS expression is primarily determined by the age of the animals. Interestingly, antioxidants such as N-acetylcysteine (NAC), ascorbic acid, or alpha-tocopherol fail to inhibit TNF-alpha/LPS/ethanol-induced increase in iNOS protein. In addition, several kinase inhibitors, including staurosporine, genistein, curcumin, and herbimycin A, were used to examine their effects on this induction. Among them, only herbimycin A potently inhibits the accumulation of nitrite and iNOS expression. In vitro kinase assay verifies that Src tyrosine kinase is rapidly activated with a peak at 1 hr after treatment with TNF-alpha/LPS/ethanol but is not activated by these agents singly or doubly. As expected, herbimycin A can block Src kinase activity under circumstances in which iNOS expression is also inhibited. However, our results do not indicate that the mitogen-activated protein kinase is activated after treatment with these agents. The study results suggest that Src tyrosine kinase plays a prominent role in transducing the signal to induce iNOS expression in hepatocytes treated with TNF-alpha/LPS/ethanol.

Thrombectomy for left ventricular protruding thrombi in a patient with dilated cardiomyopathy

Left ventricular thrombus is one source of cardiogenic embolism. The protruding, mobile type is the highest risk subgroup but is rarely encountered. Thrombectomy is one choice of therapy, and variously recommended based primarily on the experience with myocardial infarction. We report a rare case of successful left ventricular thrombectomy for two protruding, mobile thrombi in a patient with idiopathic dilated cardiomyopathy in order to prevent repeat embolization.

Continuous antegrade warm blood cardioplegia attenuates augmented coronary endothelium-dependent contraction after cardiac global ischemia and reperfusion

BACKGROUND

Experiments were designed to evaluate the effect of warm blood cardioplegia on endothelium-dependent contraction of the coronary endothelium after cardiac global ischemia and reperfusion.

METHOD

Dogs (n = 12 in each group) were exposed to extracorporeal circulation with the body temperature at 37 degrees C (group 1) or 28 degrees C (groups 2 and 3). The ascending aorta was crossclamped for 120 minutes while continuous infusion of warm blood cardioplegec solution (group 1) or intermittent infusion of cold (4 degrees C) crystalloid cardioplegic solution (group 2) was performed via the coronary arteries through the aortic root. Cardioplegic solution was not used in group 3 animals. The heart was then allowed to function for 60 minutes of reperfusion. Reperfused (groups 1, 2, and 3) and control (group 4) coronary arteries were then harvested for study.

RESULTS

Perfusate hypoxia caused endothelium-dependent contraction in the arteries of all four groups that could be attenuated by NG-monomethyl-L-arginine (L-NMMA) or L-NMMA plus D-arginine, but not by L-NMMA plus L-arginine or endothelin receptor A and B antagonist PD 145065. The endothelium-dependent contraction results in groups 2 and 3 (75% +/- 4% and 80% +/- 5%, respectively) were significantly greater than those in groups 1 and 4 (15% +/- 3% and 18% +/- 5%, respectively). Scanning electron microscope studies showed that platelet adhesion and aggregation, areas of microthrombi, disruption of endothelial cells, and separation of the intercellular junction could be found in coronary segments from groups 2 and 3, but not in vessels from groups 1 and 4.

CONCLUSION

These experiments suggest that global ischemia and reperfusion enhances hypoxia-mediated endothelium-dependent contraction of the coronary endothelium and damages the ultrastructure. These kinds of changes can be prevented by continuous antegrade infusion of warm blood cardioplegic solution during global ischemia.

Home-made endoloops for bullous lung disease: a case report

Various surgical techniques for bulla ablation have been used since the introduction of video-assisted thoracoscopic surgery. Endoscopic stapler resecting (Endo-GIA) is now the most common procedure for bulla ablation. Other endoscopic techniques include bulla suturing, clipping, laser ablation and electrocauterization. We present here a select report on using a "home-made" endoloop on a patient with bullous lung disease. No intraoperative morbidity was attributable to the procedure. The operating room time was 110 minutes, and ventilator support was given for 18 hours. The chest tube was removed on day 7 and the patient discharged on the ninth postoperative day uneventfully. The patient exhibited subjective improvement in his symptom preceptions during an one-month follow-up examination. A comparison of pre- and post operative functional evaluation showed increase in FEV1 (from 0.45 L to 1.02 L) during 3-month follow-up. From our experience, thoracoscopic home-made endoloop ligation is a safe and cost effective means of volume reduction surgery for bullous emphysema that interferes with optimum function of the adjacent lung parenchyma.

Video-assisted thoracic surgery in treatment of chest trauma

Although the indications for video-assisted thoracic surgery (VATS) have expanded rapidly, especially in the areas of therapeutic and operative procedures, its role in the definite surgical treatment of chest trauma is not clear. From July 1994 to December 1995, 56 patients with hemothorax or posthemothorax complications resulting from chest trauma received thoracic surgery. Their ages ranged from 17 to 71 years. Mechanisms of injury included penetrating (n = 23) and blunt injury (n = 33). VATS was successfully applied in 50 patients; six patients with cardiovascular injuries (n = 4) or minor chest wall lacerations (n = 2) did not receive VATS. All patients who received VATS survived, with no morbidity. Twelve of the 50 patients treated with VATS would have otherwise had to undergo thoracotomy. Our results indicate that VATS can be safely used in hemodynamically stable patients with no cardiovascular or great vessel injury, sparing many patients the pain and morbidity associated with thoracotomy. Additionally, use of VATS may reduce the likelihood of posthemothorax complications by allowing early direct inspection of the chest wall, because VATS has a lower associated risk and can be performed with a lower index of suspicion than can standard thoracotomy.

Video-assisted coronary artery bypass grafting during hypothermic fibrillatory arrest

BACKGROUND

Hypothermic fibrillatory arrest without aortic cross-clamping is a technique for quieting the heart during coronary artery bypass grafting. This report reviews the preliminary results with this technique in 4 patients having video-assisted coronary artery bypass grafting.

METHODS

Four male patients 28.5 to 64.5 years old (mean age, 45.4 years) underwent operation for unstable angina. With video-assisted techniques, coronary artery bypass grafting was performed through a left anterior minithoracotomy with femoral-femoral cardiopulmonary bypass without cross-clamping the aorta. The myocardium was protected by continuous coronary perfusion during hypothermic fibrillatory arrest.

RESULTS

A left internal thoracic artery graft was anastomosed to the left anterior descending coronary artery in each patient. The posterior descending branch of the right coronary artery was grafted with a pedicled right gastroepiploic artery in 1 patient. The duration of cardiopulmonary bypass was 72 to 127 minutes (mean duration, 92 +/- 21 minutes). The postoperative course of each patient was uneventful. Follow-up (range, 3.9 to 5.8 months; mean follow-up, 4.9 months) was complete for all patients. There were no late deaths. Coronary angiography showed patent grafts. All patients were in New York Heart Association functional class I or II (mean class, 1.25).

CONCLUSIONS

Hypothermic fibrillatory arrest is a simple and effective method of quieting the heart, thereby providing a motionless operative field for video-assisted coronary artery bypass grafting.

Impaired endothelium-dependent relaxation after cardiac global ischemia and reperfusion: role of warm blood cardioplegia

OBJECTIVES

Experiments were designed to determine whether coronary endothelial dysfunction after cardiac global ischemia and reperfusion could be prevented by warm blood cardioplegic solution.

BACKGROUND

The coronary endothelium produces endothelium-derived relaxing factor (EDRF) to prevent vasospasm and thrombosis. After ischemia and reperfusion, endothelium-dependent relaxation (EDR) is diminished as a result of G-protein dysfunction.

METHODS

Dogs were exposed to extracorporeal circulation in 37 degrees C (group 1) or 28 degrees C (groups 2 and 3). The heart was ischemic for 120 min while continuous warm blood cardioplegic solution (group 1) or intermittent cold (4 degrees C) crystalloid cardioplegic solution was not used in group 3 animals. The heart was then allowed to function for 60 min of reperfusion.

RESULTS

Endothelium-derived relaxation in response to acetylcholine, adenosine diphosphate and sodium fluoride of the coronary rings of group 1 was significantly different from that of groups 2 and 3 but was not significantly different from that of group 4. In contrast, EDR in response to the receptor-independent calcium ionophore agonist A23187 was not significantly different between the four groups. Scanning electron microscopic studies showed that platelet adhesion and aggregation, area of microthrombi, disruption of endothelial cells and separation of the intercellular junction could be found in coronary segments of groups 2 and 3 but not in vessels of groups 1 and 4.

CONCLUSIONS

These experiments suggest that cardiac global ischemia and reperfusion impair receptor-mediated release of EDRF from the coronary endothelium with G-protein dysfunction. This type of coronary endothelial dysfunction can be prevented by continuous anterograde infusion of warm blood cardioplegic solution during global ischemia.

An alternative technique in the management of bullous emphysema. Thoracoscopic endoloop ligation of bullae

STUDY OBJECTIVES

With the improvements in video-assisted thoracoscopic surgery, more older patients and patients with respiratory impairments are undergoing bulla ablation using new and costly technology. We evaluated the cost-effective technique of thoracoscopic endoloop ligation of bullae in patients with bullous emphysema.

PATIENTS

From March 1992 through January 1996, 79 advanced age (mean age, 64 years) and oxygen dependency patients underwent thoracoscopic procedure using endoloop ligation for treatment of bullous emphysema. Clinical data were collected from chart review. Only patients with radiographically confirmed diagnosis of bullous emphysema were included in this evaluation. Thoracoscopic endoloop ligation of bulla was carried out under general anesthesia with double-lumen endotracheal tube and single-lung ventilation.

RESULTS

Sixty-five patients (82%) exhibited subjective improvement in their symptom status at 3-month follow-up (from grade 2 or 3 to grade 1 or 2) according to the Modified Medical Research Council dyspnea scale. The mean duration of chest drainage was 6 days (range, 4 to 16 days). Average hospital stay was 9.5 days (range, 5 to 26 days). There was no postoperative death. A comparison of preoperative and postoperative functional evaluation was available in only 16 patients who showed an increase in FEV1 (from 0.85 to 1.02 L) and a decline in residual volume after operation. Complications include persistent airleak over 10 days in seven patients (8.9%), wound infection in three patients, and localized empyema in two patients. There was no recurrence after a mean follow-up of 21 months.

CONCLUSION

These encouraging results have shown that thoracoscopic endoloop ligation of bulla has proved to be a safe, reliable, and cost-effective technique for bullous emphysema. With careful preoperative evaluation and meticulous postoperative care, many patients could be rehabilitated by endoloop litigation of the bullae.

Isolated common iliac artery occlusion secondary to atherosclerotic plaque rupture from blunt abdominal trauma: case report and review of the literature

Traumatic isolated common iliac artery occlusion is unusual. Only rare cases of common iliac arterial injuries resulting from blunt abdominal trauma have been reported, and most of them were attributed to the seat-belt syndrome and associated with visceral organ perforation or pelvic fracture. We reported an unusual isolated common iliac artery occlusion secondary to atherosclerotic plaque rupture from blunt abdominal compressive trauma without other visceral injury. This case presented with acute limb ischemia and paralysis that was successfully treated by thromboendarterectomy. The symptoms and signs, surgical modalities, and associated injuries were reported and the literature was also reviewed.

Thoracoscopic loop ligation of parenchymal blebs and bullae: is it effective and safe?

Surgeons who have gained experience and confidence with video-assisted thoracic surgery are now routinely applying the minimally invasive approach to treat patients with spontaneous pneumothorax. Although the endoscopic stapling device may be a preferred method for resection of parenchymal blebs or bullae, the stapling device is not inexpensive. In an effort to contain costs since we started performing the video-assisted thoracoscopic procedure in chest surgical diseases, we have used a self-made endoscopic loop as an alternative method. It has assisted us in performing bulla ablation in a cost-effective manner. Over a 4-year period (1992 to 1996), we assessed the efficacy of ligating parenchymal blebs and bullae with a self-made endoscopic loop by video-assisted techniques. A total of 263 ligations were performed in 250 patients. Surgical indications included recurrence (n = 146), bilaterality of the disease (n = 13), hemopneumothorax (n = 7), radiologically demonstrated large bulla (n = 9), persistent air leak (n = 52), and nonexpansion of the lung (n = 23). There were no operative deaths. Early postoperative complications included a dislodged endoscopic loop necessitating reexploration in one patient and postoperative minor wound infections in 13. The average postoperative hospitalization was 4.5 days. Two hundred seventeen patients (86.8% of all patients) were followed up for a median of 28 months (1 to 46 months) after the operation. There have been no recurrences to date. Our results showed that thoracoscopic loop ligation is safe and effective in managing blebs and parenchymal bullae, with a lower cost, fewer complications, and a lower recurrence rate than provided by standard surgical techniques. On the basis of our results, we advocate the use of the self-made endoscopic loop for ligation of parenchymal blebs and bulla in patients with spontaneous pneumothorax to achieve a truly cost-effective and minimally invasive thoracoscopic procedure.

Video-assisted thoracoscopic operation for interruption of patent ductus arteriosus in adults

BACKGROUND

Patent ductus arteriosus (PDA) is a frequent congenital heart disease encountered in premature neonates, infants, and children. Video-assisted endoscopic techniques have been used in PDA interruption since 1993. Almost all the experiences are in pediatric patients. Applications in adults with PDA have been limited.

METHODS

We report our experience of video-assisted thoracoscopic surgical ligation of PDA in adults. From August 1995 to January 1996, 60 patients with PDA were operated on with a video-assisted thoracoscopic technique. Twelve adults were identified with mean age of 30 years (range, 20 to 57 years). With the patient under general anesthesia and double-lumen endotracheal intubation, two 5-mm holes were made in the left lateral chest wall. Another 4-cm incision was made in the left third intercostal space for manipulation, dissection, and ligation. Conventional surgical instruments were used except an endoscopic grasper and an endoscopic tube that connected to a video camera. The surgical procedure was viewed on a video screen. Transesophageal echocardiography was used for monitoring during PDA ligation.

RESULTS

All patients had successful ligation of the PDA. There was no surgical mortality, but there was one morbidity; transient recurrent nerve injury, which recovered 3 months later. Ten patients were extubated in operative room and 2 patients were extubated 2 hours after the operation. Tube thoracostomy was performed in the first 2 cases; it was omitted thereafter. No patients needed narcotic to control chest pain. Postoperative follow-up by echocardiography showed faint ductal flow in 1 patient without any murmur. All patients were discharged within 3 days after the operation.

CONCLUSIONS

Our experience suggests that with refinement of instruments and surgical technique, video-assisted thoracoscopic surgical ligation can be safely applied not only in pediatric patients, but also in adults with PDA.

Impaired endothelium-dependent relaxation of human hepatic arteries after preservation with the University of Wisconsin solution

OBJECTIVE

To evaluate the effect of University of Wisconsin solution on endothelium-dependent relaxation and contraction of human hepatic arteries in vitro.

DESIGN

Human hepatic arteries were harvested from 24 patients with hepatocellular carcinoma who had undergone hepatectomy.

SETTING

A tertiary care center.

INTERVENTIONS

Human hepatic arteries (n = 6 in each group) were harvested during resection for hepatocellular carcinoma. The arteries in group 1 (i.e., the control group) were immediately studied without preservation. The arteries in group 2 were preserved in cold (4 degrees C) physiological solution for 1 hour, while the arteries in groups 3 and 4 were preserved in University of Wisconsin solution for 1 and 16 hours, respectively. Segments of control and preserved hepatic arteries with or without endothelium were then suspended in organ chambers to measure the isometric force.

RESULTS

The relaxation of segments of the hepatic arteries with endothelium in response to acetylcholine and adenosine diphosphate was significantly (P < .05) greater than that of segments without endothelium. The maximal relaxation of hepatic arterial segments with endothelium in groups 3 and 4 in response to acetylcholine was notably different from that of segments in groups 1 and 2. The maximal relaxation of hepatic arterial segments with endothelium in groups 3 and 4 in response to adenosine diphosphate was notably different from that of segments in groups 1 and 2. Perfusate hypoxia (mean +/- SD PO2, 30 +/- 5 mm Hg) caused the endothelium-dependent contraction of the arteries (the median initial tension in groups 1, 2, 3, and 4 was 251%, 233%, 276%, and 260%, respectively; P > .05).

CONCLUSIONS

The endothelium-dependent relaxation of human hepatic arteries in response to acetylcholine and adenosine diphosphate was notably attenuated by University of Wisconsin solution. The impaired endothelium-dependent relaxation by University of Wisconsin solution and the prominent endothelium-dependent contraction of human hepatic arteries would favor vasospasm and thrombosis after hepatic transplantation.

Primary chondrosarcoma of the heart: a case report

Chondrosarcoma involving the heart has been previously reported but is extremely rare. Most chondrosarcoma described in the literature are secondary, and the primary site can be identified. We present an unusual case of primary cardiac chondrosarcoma which originated in the left atrium. Severe pulmonary edema was the first presentation. The sarcoma subsequently metastasized to the mandible and finally recurred in the right heart causing severe pulmonary emboli and myocardial failure.

Video-assisted cardiac surgery. Preliminary experience in reoperative mitral valve surgery

OBJECTIVES

Video-assisted endoscopic techniques had been applied in the surgical correction of patent ductus arteriosus, vascular ring, or coronary artery disease. However, it has been used only recently in the correction of reoperative mitral valve lesions.

DESIGN

Video-assisted cardiac operations were performed on four patients who had received surgical interventions on their mitral valves and needed emergent reoperation.

PATIENTS

Four patients (3 men and 1 woman) received emergency surgery from September to December 1995 for thrombosis of mechanical mitral prosthesis (2 patients) and severe mitral regurgitation with previously failed mitral valve repair (2 patients). Six previous operations had been performed on these mitral valves. Patient ages ranged from 26.7 to 68.1 years (mean, 47.3 years). Preoperatively, acute pulmonary edema occurred in two patients, cerebral emboli occurred in one patient, and sepsis was found in one patient. Mechanical ventilatory support was used in two patients before operation.

INTERVENTION

The operations were performed through right anterior minithoracotomy, guided by video-assisted endoscopic techniques with femoro-femoral extracorporeal circulation. The operative procedures were thrombectomy of mitral prosthesis in two patients, mitral valve repair in one patient, and mitral valve replacement in one patient.

RESULTS

The duration of extracorporeal circulation was 166 to 320 min (222 +/- 67 min) and the operation time was 4.6 to 6.8 h (6.1 +/- 1.0 h). All patients recovered from the operations rapidly with uneventful postoperative courses except 1 patient who had sepsis preoperatively and died 2 months later.

CONCLUSION

Our experience demonstrates that video-assisted cardiac surgery is technically feasible and could be performed in reoperation of the mitral valve.

Prolonged circulatory arrest in moderate hypothermia with retrograde cerebral perfusion. Is brain ischemic?

BACKGROUND

Circulatory arrest (CA), which provides a bloodless field and good visualization without the need of aortic cross-clamp, is commonly used to facilitate repair of aortic lesions. However, extended periods of CA may impair cerebral metabolism and cause ischemic injury. Studies were performed to evaluate the efficacy of retrograde cerebral perfusion (RCP) in protecting the brain from ischemic injury during a prolonged period of CA in moderate hypothermia.

METHODS AND RESULTS

Twenty-three patients (18 men and 5 women) were operated on for aortic lesions (17 acute type A aortic dissection and 6 chronic type A aortic dissection with Marfan's syndrome). The aortic operations were performed with CA (58 to 104 minutes; mean +/- SD, 75 +/- 12 minutes) at a rectal temperature of 23.3 +/- 0.5 degrees C (21 degrees C to 25 degrees C). For RCP, cold (14 degrees C to 18 degrees C) oxygenated blood (300 mL/min) was pumped to the superior vena cava with internal jugular venous pressure of 15 +/- 5 mm Hg. The cardiopulmonary bypass time was 157 +/- 18 minutes. Cortical blood flow during RCP detected by subdural laser Doppler probe was 10 +/- 5% of baseline. Percent oxygen extraction and pyruvate and lactate levels (26 +/- 2% and 0.43 +/- 0.17 and 45 +/- 16 mg/dI) were insignificantly different from those before CA (28 +/- 3% and 0.71 +/- 0.08 and 62 +/- 20 mg/dL, P > .05). Creatine kinase-BB isoenzyme was undetectable. All but 1 patient survived the operation (95.5%) and woke up without neurological deficit. Follow-up (mean, 13 months) was complete in all survivors. There were no late deaths. Cerebral functional studies performed 3 months after discharge showed results insignificantly different from those of the normal control subjects.

CONCLUSIONS

There is no evidence of ischemia of the brain during prolonged moderate hypothermic CA with the aid of RCP. Retrograde cerebral perfusion effectively extends the safe time of CA. Deep hypothermia during CA seems unnecessary.

Experimental patch bronchoplasty with ringed vascular graft

The best surgical technique in bronchial reconstruction is resection and end to end anastomosis, but in some cases either pathology length, reduction in tissue elasticity, or such circumstances, patch bronchoplasty may be necessary to reestablish air-passage continuity. The purpose of this experiment would thus try to investigate the possibility of using ringed polytetrafluoroethylene (PTFE) graft to repair the diseased bronchus. A 2 x 1 cm patch segment of bronchus resected in 10 dogs were followed up with monthly bronchoscopy and endoscopic photography. Euthanasia was performed at 3, 6 and 9 months or when signs of respiratory distress developed. At postmortem examination, the anastomoses were examined grossly and with light microscopy. In 5 of the 10 dogs that underwent bronchial repair with PTFE, granulation tissue developed at the anastomoses resulting in airway obstruction after 6 to 9 months. No epithelial growth occurred over the graft between the suture lines. We conclude that the granulation tissue formation at the anastomosis and the lack of respiratory epithelial ingrowth across the graft makes PTFE unsuitable for patch repair of the bronchial defect.

Video-assisted cardiac surgery in closure of atrial septal defect

BACKGROUND

Video-assisted endoscopy has been applied in the management of a variety of intrathoracic vascular lesions. Here we report its use in the correction of intracardiac congenital defects.

METHODS

Eight patients (3 male and 5 female) underwent operation for closure of an atrial septal defect. The patients ranged in age from 2.0 to 60.9 years (mean, 19.2 +/- 19.0 years). The patients weighed 11 to 66 kg (mean, 41.3 +/- 23.5 kg). The ratio of pulmonary blood flow to systemic blood flow ranged from 2.0 to 6.0 (mean, 3.4 +/- 1.3). The mean pulmonary artery pressure was 19.7 +/- 4.0 mm Hg (range, 13 to 24 mm Hg). The operations were performed through a right anterior minithoracotomy and guided by video-assisted endoscopic techniques under femorofemoral or femoral-right atrial extracorporeal circulation. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest (rectal temperature, 22.0 degrees +/- 2.0 degrees C). Transesophageal echocardiographic monitoring was maintained during the operations. The right atrium was entered after pericardiotomy. Primary closure of the defect was performed successfully in all patients. Conventional nondisposable instruments were used for dissection, grasping, suturing, and hemostasis.

RESULTS

The durations of extracorporeal circulation and operation ranged from 47 to 126 minutes (mean, 80 +/- 31 minutes) and from 2.2 to 4.5 hours (mean, 3.1 +/- 0.8), respectively. All patients recovered from the operation rapidly with an uneventful postoperative course.

CONCLUSIONS

Our experience demonstrates that video-assisted cardiac surgery is technically feasible and can be used with excellent results for the repair of congenital heart defects in general.

Augmented endothelium-dependent constriction to hypoxia early and late following reperfusion of the canine coronary artery

1. Canine coronary arteries with intact endothelium respond to hypoxaemia or serotonin infusion with dilatation, but when the endothelium is injured or dysfunctional, these stimuli can cause constriction. The present studies investigated whether or not regional ischaemia and reperfusion alter endothelium-dependent responsiveness of canine coronary arteries in vivo and in vitro. 2. In organ chamber experiments, isolated control and reperfused coronary artery rings were contracted with prostaglandin F2 alpha and exposed to hypoxia (PO2 less than 5 mmHg). 3. Hypoxia augmented the response of reperfused arteries more than that of controls. The hypoxic augmentation was blocked by NG-monomethyl-L-arginine, an inhibitor of nitric oxide synthesis from L-arginine. 4. These findings demonstrate that early following coronary reperfusion the hypoxic augmentation, which is mediated by a nitric oxide-dependent pathway in the endothelium, is facilitated. 5. In vivo studies revealed hyperconstriction of reperfused arteries in response to hypoxaemia (PO2 = 30-40 mmHg) and administration of either serotonin or ergonovine. 6. Twelve weeks following reperfusion injury, coronary arteries still exhibited augmented endothelium-dependent hypoxic augmentations in vitro, which were inhibited by NG-monomethyl-L-arginine. 7. Furthermore, resting coronary segments with endothelium displayed hypoxia-induced contractions that could not be inhibited by indomethacin, the lipoxygenase inhibitor AA861, superoxide dismutase plus catalase, deferoxamine, ouabain, or NG-monomethyl-L-arginine. 8. These endothelium-dependent hypoxic response may play a role in the pathogenesis of hyperconstriction (vasospasm) following coronary reperfusion.

Video-assisted mitral valve operations

BACKGROUND

Video-assisted endoscopy has been applied frequently in the management of a variety of surgical diseases. However, it has rarely been applied in mitral valve surgery.

METHODS

We report 2 patients who received emergency operations for thrombosis of a mitral prosthesis (patient 1, a 68-year-old man) and acute mitral regurgitation due to rupture of anterior chordae (patient 2, a 75-year-old woman). They both had severe congestive heart failure. Cardiogenic shock was noted in patient 2. The mitral valve was approached through a right anterior minithoracotomy with the aid of an endoscope by means of projected images on the video monitor under femorofemoral cardiopulmonary bypass. The aorta was not cross-clamped, and the myocardium was protected by continuous coronary perfusion with hypothermic fibrillatory arrest. The left atrium was entered posterior to the interatrial groove. Thrombectomy and mitral valve repair were performed successfully.

RESULTS

The duration of extracorporeal circulation was 204 and 147 minutes, respectively. Both patients recovered from the operation rapidly with uneventful postoperative courses.

CONCLUSIONS

Our preliminary results suggest that video-assisted endoscopic cardiac surgery is technically feasible and could be performed in the milieu of open heart surgery.