Hideaki Nohara

Retrograde cerebral perfusion versus selective cerebral perfusion as evaluated by cerebral oxygen saturation during aortic arch reconstruction

BACKGROUND Time limits for neuroprotection by retrograde cerebral perfusion (RCP) and selective cerebral perfusion (SCP) in aortic arch aneurysm repair or dissection are undergoing definition. METHODS Using near-infrared optical spectroscopy, changes in regional cerebrovascular oxygen saturation (rSO2) were compared between the two perfusion methods. RESULTS Immediately before cardiopulmonary bypass, baseline rSO2 was 63.9%+/-6.9% for the RCP and 66.1%+/-5.3% for the SCP group (no significant difference). As patients were core-cooled to 20 degrees C, rSO2 increased to 73.1%+/-8.8% and 74.1%+/-7.9% in the RCP and SCP groups, respectively. With circulatory arrest, rSO2 suddenly decreased. After starting cerebral perfusion, rSO2 returned to prearrest values in the SCP group but continued decreasing steadily in the RCP group, to levels below baseline after about 25 minutes. At the end of perfusion, rSO2 was 57.4%+/-12.2% for the RCP group and 71.7%+/-6.9% for the SCP group, and the ratio of rSO2 to baseline value was 0.89 for RCP and 1.08 for SCP despite a shorter brain perfusion time for RCP (38.8+/-18.0 versus 103.3+/-43.3 minutes). Three of 5 patients whose ratios of rSO2 to baseline at the end of brain protection were 0.7 or less had neurologic deficits. CONCLUSIONS Although SCP showed no clinically important time limitation, rSO2 continued to decrease with time during RCP. An rSO2 ratio less than 0.7 could represent a critical lower limit.

Early results of coronary grafting using ultrasonically skeletonized internal thoracic arteries

BACKGROUND We have developed an ultrasonic complete skeletonization technique for obtaining internal thoracic artery (ITA) grafts and have used this method clinically since January 1998. In this report, we discuss the early results of bilateral ITA grafts obtained with our method. METHODS We studied 200 consecutive patients who underwent coronary artery bypass grafting using ITAs obtained by this technique. Angiography of the grafts was performed in 188 patients (94%) within 1 month after coronary artery bypass grafting. RESULTS The ITA grafts were about 4 cm longer than pedicled ITA grafts. The free flow through the grafts was at least 30% higher than through pedicled ITAs. The early patency rate determined by postoperative angiography of the grafts was 99.7% for left ITAs and 100% for right ITAs. No patient required postoperative intervention or repeated surgery. CONCLUSIONS Ultrasonic complete skeletonization increases the effective length of ITA bypasses, improves free flow through the bypasses, and it is less invasive than conventional pedicled harvesting. These excellent early results indicate that this technique is a straightforward, safe, less invasive, and optimal method for obtaining ITA bypass grafts.

Pharmacologic intervention for ischemic brain edema after retrograde cerebral perfusion

Retrograde cerebral perfusion has recently been the focus of interest as a simple new technique of brain protection during aortic arch operations. We undertook the experimental protocol of 120 minutes of retrograde cerebral perfusion followed by antegrade reperfusion. Eighteen mongrel dogs were used. Retrograde cerebral perfusion was maintained at a flow rate of 150 to 250 ml/min to keep the perfusion pressure from 15 to 25 mm Hg. Animals were divided into three groups as follows: in group I, no treatment was received during and after retrograde cerebral perfusion; in group II, mannitol (2 gm/kg) was administered before cardiopulmonary bypass was restarted; and in group III, antivasospastic substance (1,2-bis nicotinamido]-propane) was continuously injected during and after retrograde cerebral perfusion (1 mg/kg per minute). Cerebral blood flow decreased during retrograde cerebral perfusion in all three groups. Cerebrovascular resistance showed marked increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with the values in groups II and III (group I: 3.35 +/- 0.73 and 5.00 +/- 1.57 mm Hg/ml per 100 gm per minute; group II: 1.30 +/- 0.33 and 1.03 +/- 0.17 mm Hg/ml per 100 gm per minute; group III: 1.24 +/- 0.41 and 0.98 +/- 0.24 mm Hg/ml per 100 gm per minute). The oxygen extraction level was reduced by cooling, but it rose to a higher level as a result of significant desaturation of returned blood even in deep hypothermia during retrograde cerebral perfusion. Both cerebral metabolic rate of oxygen and cerebral metabolic rate of glucose remained at low levels during retrograde cerebral perfusion. Ratios of cerebral blood flow to cerebral metabolic rate of oxygen and cerebral blood flow to cerebral metabolic rate of glucose were markedly reduced during retrograde cerebral perfusion. Intracranial pressure showed significant increases 30 and 60 minutes after cardiopulmonary bypass was restarted in group I compared with values in group II or group III (group I: 22.7 +/- 2.8 and 20.6 +/- 5.1 mm Hg; group II: 6.3 +/- 1.8 and 5.3 +/- 1.3 mm Hg; group III: 4.2 +/- 1.7 and 7.7 +/- 2.8 mm Hg). Water content of the brain tissue in group I (77.54% +/- 0.29%) was significantly higher than that in group II (74.71% +/- 0.76%) or group III (74.14% +/- 0.48%). These data suggest that the supply of oxygen or glucose by retrograde cerebral perfusion is not enough to maintain sufficient cerebral metabolism, which may cause brain edema during antegrade reperfusion.(ABSTRACT TRUNCATED AT 400 WORDS)

Pulmonary sequestration with high levels of tumor markers tending to be misdiagnosed as lung cancer

A 62-year-old man with hemoptysis and an abnormal shadow on chest roentgenogram was diagnosed as having anomalous systemic arterial supply to the normal basal segment of the left lower lobe. The preoperative serum carbohydrate antigen 19-9 and carcinoembryonic antigen levels were 73.8 units/ml and 10.8 ng/ml, respectively. Histopathological examination confirmed that the lesion was an intralobar pulmonary sequestration without air connection. There was no malignant finding in the resected specimen. The serum values of tumor markers returned to their approximate normal ranges after lower lobectomy.

Emergency Percutaneous Cardiopulmonary Bypass Support for Acute Myocardial Infarction

We assessed the efficacy of emergency percutaneous cardiopulmonary bypass support (PCPS) in the treatment of patients with acute myocardial infarction complicated by cardiogenic shock. Emergency PCPS was instituted in 21 consecutive patients beginning in 1991. After the stabilization of the hemodynamics, coronary reperfusion was performed by means of coronary artery bypass grafting or percutaneous transluminal coronary angioplasty. Of the seven patients with acute myocardial infarction involving either the left main or two-vessel territories, five survived more than 1 month, but only one patient remained alive and well after 20 months. The main cause of death for this group was low output syndrome. Four of 12 patients with acute left main trunkal occlusion in the catheter laboratory survived and showed a preserved cardiac function (mean followup 28.5 months). The main cause of death for this group was brain damage. Two patients with single-vessel territory acute myocardial infarction underwent PCPS to treat refractory ventricular fibrillation. Both patients were still alive and well at a 12-month followup. Percutaneous cardiopulmonary bypass support successfully stabilized the hemodynamics, allowing time to perform revascularization for all three groups of patients with life-threatening acute myocardial infarction. Recanalization was nevertheless unable to salvage the damaged myocardium in cases of prolonged ischemic time.

Acute Left Atrial Thrombus Causing Cardiogenic Shock Following Mitral Valve Replacement : Report of a Case

We report herein the rare case of a 53-year-old woman who developed cardiogenic shock due to an acute left atrial thrombus following replacement of the mitral valve. A definitive diagnosis was not able to be made using precordial echocardiography because of the broad, flat shape of the thrombus; however, transesophageal echocardiography imaged the thrombus in detail. The patient was initially stabilized by percutaneous cardiopulmonary support after which a thrombectomy was successfully performed.

Retrograde Cerebral Perfusion for Aortic Arch Operation

Deep hypothermic retrograde cerebral perfusion (RCP) has recently been the focus of interest as a simple new technique of brain protection during the operation for thoracic aneurysms. During the period from January 1991 to July 1994, 21 consecutive patients underwent operations on the various portions of the thoracic aorta with the use of deep hypothermic RCP. There were 10 men and 11 women, ages ranging from twenty-eight to seventy-eight (mean 61.4) years old. There were 9 cases with true aortic aneurysm, and 12 with dissecting aneurysm. In 8 patients (38.1%) the procedures were done on an emergency basis for ruptured/impending ruptured aneurysms or acute dissecting aneurysms. Four patients died before the adequate assessment of their neurologic function. One patient had a cerebral infarction probably due to dissection of the left common carotid artery. The remaining 16 patients showed clear consciousness and had no serious neuro logic complications postoperatively. Total perfusion time averaged 297 ± 110 minutes (ranging from 162 to 548 minutes). Rectal temperatures were 20.1 ± 1.4°C (ranging from 18.0 to 22.5°C). RCP time averaged 51.3 ± 13.9 minutes (ranging from twenty-seven to eighty minutes). Blood gas analysis of the returned blood sampled from the left common carotid artery or the innominate artery and the ophthalmoscopic findings demonstrated the insufficiency of blood and oxygen supply to the brain during RCP. Therefore, RCP time should be shortened and pharmacologic cerebral protection is recommended to reduce neurologic complications during operations on the thoracic aorta using RCP.