Mikio Ohmi

Pulmonary Vascular Changes Induced by Congenital Obstruction of Pulmonary Venous Return

BACKGROUND Pulmonary venous obstruction (PVO) induces pulmonary arterial hypertension, as well as pulmonary venous hypertension, and jeopardizes the repair of cardiac lesions. METHODS Four cases of congenital mitral stenosis and 4 cases of cor triatriatum (Lucas type A), ages ranging from 2 months to 16 years, were histologically examined on pulmonary vasculature. Histometrical analysis was performed on medial thickness and intimal changes of both pulmonary arteries and veins. For comparison, the examination of pulmonary vasculature in ventricular septal defect (VSD) cases was also performed. RESULTS Medial thickening and intimal fibrosis, in both pulmonary arteries and veins with widespread lymphangiectasia, were characteristic vascular changes of PVO cases. Medial thickness of pulmonary arteries was correlated with preoperative pulmonary arterial pressure (PAP) (r = 0.77, p = 0.03 for systolic PAP), and greater than that of VSD cases. Medial thickness of pulmonary veins was also greater in PVO cases. Intimal fibrosis of pulmonary arteries and veins was seen extensively at the advanced ages, whereas no plexiform lesions or more advanced stages of pulmonary vascular disease were present. CONCLUSIONS Congenital PVO induced progressive medial thickening and intimal fibrosis in pulmonary arteries and veins accompanied by lymphangiectasia. However, no plexiform lesions or more advanced stages of pulmonary vascular disease were present, which may explain the reversibility of pulmonary hypertension due to congenital PVO.

Aortic arch aneurysm repair using selective cerebral perfusion

Seventy-seven patients underwent aortic arch aneurysm repair using selective cerebral perfusion from January 1987 to August 1992. Early and long-term results and preoperative and postoperative cerebral function were evaluated. Cerebral function was assessed by the mini mental state-Himeji test and the Wechsler adult intelligence scale. Thirty-six patients had true aneurysms, and 41 had dissection. Hospital mortality for true and dissecting aneurysms was 19.4% and 7.3%, respectively. The 5-year actuarial survival rates for true and dissecting aneurysms were 59.0% and 65.3%, respectively (not significant). There were no significant differences in test scores before or after operation. Repair or replacement of the aortic arch using selective cerebral perfusion is a safe procedure with acceptable hospital mortality.

Effects of Cardiac Surgery on Intellectual Function in Infants and Children

Intellectual function was evaluated by Gesells developmental quotient (DQ) and Binets intelligence quotient (IQ) in 161 infants and children (61 ventricular septal defects, 49 tetralogies of Fallot, 15 transpositions of the great arteries, seven atrial septal defects, five complete atrioventricular canals, five double outlet right ventricles and 19 shunt cases; average age 3.6 years) before and after cardiac surgery. There were no significant differences in preoperative DQs and IQs among the patient groups. Although average DQ scores in 21 infants with hypothermic (13–24°C) total circulatory arrest (36-70min) were not significantly different from the preoperative values, 13 patients with an arrest time >50 min showed a significant decrease in DQ scores. The postoperative DQ and IQ scores in patients without circulatory arrest or in shunt cases were not significantly impaired after surgery. It was concluded that cardiac surgery did not impair intellectual function in infants and children. although cerebral dysfunction might occur if circulatory arrest was >50 min. Copyright

Spontaneous rupture of the thoracic aorta

BACKGROUND Spontaneous rupture of the thoracic aorta without trauma, aneurysm, or dissection is an extremely rare but catastrophic disorder. Two cases of spontaneous aortic rupture are presented, both treated surgically with satisfactory results. METHODS A review of the English literature found 16 patients with the diagnosis of spontaneous rupture of the thoracic aorta from 1961 through 1998. Eighteen reported cases, including the 2 cases presented herein, are reviewed. RESULTS The representative clinical picture is one of a middle-aged hypertensive patient with acute chest pain and collapse, with imaging modalities demonstrating hemopericardium, hemomediastinum, or hemothorax. According to the reported experiences, aortography was accurate for identifying the rupture site although the findings were sometimes subtle. Misdiagnosis or nonsurgical management resulted in the patients death. All 8 patients who did not undergo aortic repair died within 3 weeks after the onset, whereas 9 of 10 patients who underwent surgical aortic repair survived. CONCLUSIONS For patients with a definitive or possible diagnosis of spontaneous rupture of the thoracic aorta, prompt operation is imperative through an optimal surgical approach to identify and repair the rupture site with appropriate circulatory support.

Effects of cardiac surgery on intellectual in and children

Abstract Intellectual function was evaluated by Gesells developmental quotient (DQ) and Binets intelligence quotient (IQ) in 161 infants and children (61 ventricular septal defects, 49 tetralogies of Fallot, 15 transpositions of the great arteries, seven atrial septal defects, five complete atrioventricular canals, five double outlet right ventricles and 19 shunt cases; average age 3.6 years) before and after cardiac surgery. There were no significant differences in preoperative DQs and IQs among the patient groups. Although average DQ scores in 21 infants with hypothermic (13–24 °C) total circulatory arrest (36–70 min) were not significantly different from the preoperative values, 13 patients with an arrest time >50 min showed a significant decrease in DQ scores. The postoperative DQ and IQ scores in patients without circulatory arrest or in shunt cases were not significantly impaired after surgery. It was concluded that cardiac surgery did not impair intellectual function in infants and children, although cerebral dysfunction might occur if circulatory arrest was >50 min.

Protection of the brain during hypothermic perfusion

The adequacy of the circuits for brain perfusion has been explored by hemodynamic assessment using the ability of the brain to autoregulate blood flow as an indicator, and by morphologic observation using carbon black or Evans blue infusion into the brain perfused antegradely or retrogradely. It is concluded that the safe pressure of cerebral perfusion needed to maintain cerebral integrity is between 40 and 50 mm Hg in both normothermic and hypothermic perfusions, a pressure that can be generated by nonpulsatile pump flows through the pump greater than 40 mL.kg-1 x min-1. Morphologic studies revealed development of focal infarctions in the brain and destruction of the blood-brain barrier by retrograde cerebral perfusion. The retrograde approach, therefore, is definitely inferior to the antegrade method. Antegrade perfusion for 90 minutes, however, produced minimal cerebral edema, suggesting the need for further improvement even in techniques of antegrade perfusion.

Extremely rapid regression of aortic intramural hematoma

diagnosed by modern imaging techniques and may follow various clinical courses. We report a case in which 2 episodes of aortic IMH occurred in different aortic segments within a 10-month period. In the first episode the IMH involving the descending thoracic aorta regressed in 1 month; however, the large IMH involving the ascending and transverse aorta rapidly regressed within 24 hours in the second episode. The patient has been treated medically and is doing well. Clinical summary. The patient was a 62-year-old woman with a complicated history: removal of a pituitary adenoma in 1987, removal of the left kidney for renal cell carcinoma in 1992, and cerebral infarction in 1996. After removal of the pituitary adenoma she had been treated with hydrocortisone (30 mg/day) and desiccated thyroid (50 mg/day) for secondary adrenal hypofunction and hypothyroidism, respectively. The first episode of aortic IMH occurred on March 8, 1998. She came to the emergency department of Saka General Hospital with the sudden onset of severe back pain. An admission computed tomographic (CT) scan showed crescentic thickening of the posterior wall of the descending thoracic aorta and a left-sided hemothorax. An aortogram demonstrated no intimal flap and an opacified false lumen or ulcer-like projection. She was treated medically and discharged on May 4, 1998. The CT scans from the first episode are shown in Fig 1. The second episode of aortic IMH occurred on January 12, 1999, during an operation for a subcutaneous and epidural abscess in the frontal region, possibly related to the previous pituitary operation. Her blood pressure suddenly fell below 50 mm Hg in systole. The emergency CT scan showed a large ascending and transverse aortic IMH and a massive left-sided hemothorax. Her general condition was stabilized until the next day, and she was referred to Sendai City Medical Center for emergency aortic repair. When another CT scan was taken, the aortic IMH had regressed completely. Since the maximal diameter of the ascending aorta was 40 mm, surgical intervention was canceled. Fluid was drained from the left pleural cavity (1170 mL; hemoglobin, 10.4 g/dL; hematocrit value, 36%), and she recovered after receiving medical treatment. The CT scans from the second episode are shown in Fig 2. Discussion. Aortic IMH is a variant of aortic dissection recognized in 17%1 to 23%2 of the patients with acute aortic 968 Brief communications The Journal of Thoracic and Cardiovascular Surgery November 1999

Brain damage after aortic arch repair using selective cerebral perfusion

BACKGROUND Selective cerebral perfusion is one of the most popular methods for cerebral protection during aortic arch repair. However, causes of postoperative brain damage are not fully understood. We analyzed brain damage after aortic arch repair using selective cerebral perfusion for true aortic arch aneurysm in regard to preoperative cerebral infarction and intracranial and extracranial occlusive arterial disease. METHODS Over a 9-year period, 60 patients with true aortic arch aneurysm underwent aortic arch repair using selective cerebral perfusion. Postoperative brain damage was evaluated in regard to preoperative cerebral infarction detected by computed tomography, magnetic resonance imaging, or both in 50 patients and intracranial and extracranial occlusive arterial disease detected by digital subtraction angiography, magnetic resonance angiography, or both in 35 patients. RESULTS Seven (12%) of the 60 patients died within 30 days of operation. Postoperative brain damage occurred in 6 (10.5%) (3, coma, and 3, hemiplegia) of 57 patients; 3 patients who died without awakening were excluded. Preoperatively, old cerebral infarction was detected in 9 patients (18%), and silent cerebral infarction (lacunar infarction and leukoaraiosis) was diagnosed in 26 patients (52%). Postoperative brain damage occurred in 3 (33%) of the 9 patients with preoperative cerebral infarction and in 3 (23%) of 13 patients with negative preoperative brain findings; this excludes 2 patients who died without awakening. No patient with silent cerebral infarction had postoperative brain damage. Occlusive arterial disease was detected in 7 patients (20%). The incidence of brain damage in these patients was 71% (5/7), which was significantly greater than that of 4% (1/28) in patients without occlusive arterial disease (p < 0.001). CONCLUSIONS Silent cerebral infarction may not be a risk factor for postoperative brain damage. Preoperative evaluation of intracranial and extracranial occlusive arterial disease provides important information as to whether a patient might sustain brain damage after aortic arch repair using selective cerebral perfusion.

Quantitative analysis of cardiac 3-L-nitrotyrosine during acute allograft rejection in an experimental heart transplantation.

BACKGROUND Recent studies have shown that nitric oxide interacts with superoxide to form peroxynitrite, a potent oxidant that modifies cellular proteins producing 3-L-nitrotyrosine (N-Tyr). This study was designed to evaluate N-Tyr quantitatively with high-performance liquid chromatography (HPLC) during cardiac allograft rejection. METHODS Rat transplanted hearts (allogeneic or syngeneic grafts) were examined with HPLC analysis, immunohistochemistry for N-Tyr, and histological studies on 0, 1, 3, and 7 days after transplantation. RESULTS No histological rejection was found in syngeneic grafts, or day 0 or 1 allografts. HPLC demonstrated that N-Tyr in allografts increased on day 1 and continued to increase through day 7, while N-Tyr was not detected in any syngeneic grafts. Immunostaining of the allografts did not show N-Tyr on day 1. CONCLUSION These results demonstrate that N-Tyr shows a time-dependent accumulation in cardiac allografts during acute rejection. N-Tyr detection using HPLC may be an useful maker for early diagnosis of acute rejection before pathological rejection occurs.

Replacement of the transverse aortic arch for type a acute aortic dissection

Surgical treatment of acute aortic dissection involving the segment of transverse aortic arch is difficult and often associated with a high mortality and morbidity. The high mortality and morbidity are primarily related to anatomic features and techniques of cerebral protection employed during the period of aortic branch occlusion needed for reconstruction. This study reports our experience of 20 consecutive cases of acute type A aortic dissection treated by repair or replacement of the transverse aortic arch during emergency operation. Ages of the patients ranged from 56 to 76 years. All patients were referred to us within 2 weeks of onset (mean time, 58 hours). Selective cerebral perfusion or deep hypothermia with complete circulatory arrest was employed during the period of aortic branch occlusion. Duration of cerebral perfusion, circulatory arrest, myocardial ischemia, and cardiopulmonary bypass averaged 106 minutes, 32 minutes, 127 minutes, and 248 minutes, respectively. There were three operative deaths. All three dissections were ruptured ones, and the patients died of hemorrhage, deep coma, or multiple organ failure. One patient died of infection 3 months after operation. The remaining patients are alive and well without any detectable neurological deficit 1 month to 4 years postoperatively. This experience emphasizes that repair or replacement of acute type A aortic dissection involving the aortic arch can be performed safely by adequate selection of patients, supportive measures, and operative methods.