Eriya Okuda

Surgical reconstruction of an ascending aortic dissection in Takayasu's arteritis

A 45-year-old Japanese woman with Stanford type A dissecting aortic aneurysm underwent a reconstructive operation on the ascending aorta. Histopathological diagnosis was Takayasus arteritis in the chronic and inactive phase. It is very rare that a dissecting aortic aneurysm results from Takayasus arteritis. Long-standing hypertension and fragility of the aortic media due to disruption of elastic fibers were suspected to cause dissection in the entire aorta in this case.

Protective Effects of Intrathecal Lidocaine Administration on Ischemic Injury of the Spinal Cord

The protective effects of intrathecal lidocaine administration on experimental ischemic spinal cord injury following aortic cross-clamping (AXC) were studied. Twelve mongrel dogs were divided into two groups, six animals in an intrathecally saline-administered group (control group) and the other six in an intrathecally lidocaine-administered group (lidocaine group). The dose of lidocaine administration was determined by the change of somatosensory-evoked potential traces generated by brachial nerve stimulation. Following administration of the agents, all dogs underwent cross-clamping of the thoracic aorta and the left subclavian artery for 60 minutes. Mean proximal aortic pressure during AXC remained in a similar range to baseline pressure until 40 minutes after AXC in the lidocaine group, while it increased significantly in the control group. The ratio of mean distal aortic pressure to mean proximal aortic pressure during AXC (D/P), which was calculated for estimation of collateral blood flow changes, gradually increased in the lidocaine group, but did not change in the control group. Four of six dogs had spastic paraplegia in the control group, but none in the lidocaine group (p < 0.05). Histological examination revealed that extensive infarction of the gray matter was noticed in the control group, but changes in the lidocaine group were only slight. From these results, it was concluded that intrathecal lidocaine administration controlled proximal hypertension effectively, increased D/P during AXC, and diminished neurological damages following AXC.

Short-term treatment with synchronized coronary venous retroperfusion before full reperfusion significantly reduces myocardial infarct size

The efficacy of short-term synchronized coronary venous retroperfusion (SRP) before full arterial reperfusion was studied in a canine model. A control group (n = 6) was subjected to 90 minutes of occlusion of the left anterior descending coronary artery, which was followed by 6 hours of reperfusion. In another group (n = 6) the left anterior descending coronary artery was occluded for 2 hours followed by 5.5 hours of reperfusion. In this group SRP was applied for 30 minutes before full reperfusion. Myocardial regional blood flow was measured with the use of colored microspheres. During occlusion of the left anterior descending coronary artery, there was severe myocardial ischemia in both groups. Blood flow in the subendocardial area was, however, significantly better in the SRP group (0.51 +/- 0.17 ml/min/gm after 3.5 hours of reperfusion) than in the control group (0.29 +/- 0.16 ml/min/gm) after 4 hours of reperfusion (p less than 0.05). Left ventricular function was assessed as global ejection fraction from a left ventriculogram. Ejection fraction was reduced during ischemia in both groups (control = 38% +/- 3%, SRP = 32% +/- 8%). This dysfunction remained after 4 hours of reperfusion. Infarct size was assessed by means of triphenyltetrazolium chloride staining. The myocardial area at risk was similar in the two groups (control = 33.1% +/- 5.3%, SRP = 30.6% +/- 6.5%). Infarct size, which was expressed as the percent of the area at risk, was significantly smaller in the SRP group (17.2% +/- 14.6%) than in the control group (36.0% +/- 8.1%; p = 0.0197).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical application of intrathecal lidocaine administration in surgery of the descending thoracic aorta

We studied the protective effects of intrathecally administered lidocaine against ischemic spinal cord injury during surgery. Seven patients (mean age 63.7 years, male∶female=6∶1) with descending thoracic aortic aneurysms underwent reconstructive surgery. Following intrathecal lidocaine administration (10 ml), the operation was performed under femorofemoral bypass with an oxygenator. The aorta was cross-clamped at the distal end of the descending thoracic aorta and the proximal end of the lesions. The cross-clamping time was 47.1±23.3 minutes (mean ± SD). The operative procedure was total replacement of the descending thoracic aorta in five cases and patch closure in two. There were no operative deaths but paraparesis developed in two cases of total replacement. Neurological deficit was transient and disappeared in one case. In the other case, with 88 minutes of normothermic aortic cross-clamping, paraparesis gradually improved but was persistent after 7 months of follow-up. Graft anastomosis at the distal aortic arch was time consuming in this case and presumably caused prolonged spinal cord ischemia. Intrathecal administration of lidocaine was likely to reduce ischemic spinal cord injury and increase tolerance of the spinal cord to ischemia caused by prolonged aortic cross-clamping. This method was considered to provide a useful assistance to expand the safety limit of spinal cord ischemia in surgical reconstruction of the descending thoracic aorta requiring aortic occlusion. Tissue protective effects of intrathecal lidocaine administration may be further augmented by combining with deep hypothermia.

Reconstruction Surgery of the Ascending Aorta and the Aortic Arch under Deep Hypothermia with Circulatory Arrest.

1988年1月から1991年6月までに20℃以下の超低体温下循環停止法を用いて, 8例の上行-弓部大動脈再建術を行った. 平均年齢62.0±11.8歳, 男女比3:5で, 4例が緊急手術であった. 病型は Stanford A型解離性大動脈瘤7例, 上行-弓部大動脈の真性動脈瘤1例であった. 手術時間432.6±147.3分, 体外循環時間191.9±66.1分, 循環停止時間31.0±10.8分 (16～47分) であった. 全例胸骨正中切開下に上行-弓部大動脈人工血管置換術を施行し, 2例に腕頭動脈再建術を行った. 出血量4,685±2,943ml, 輸血量4,659±2,779mlであった. ICU帰室後2～19時間で全例覚醒し, 脳合併症はみられなかった. 術後に薬剤性腎機能障害, 洞性不整脈および軽度の肝機能障害各1例を認めたが手術死亡, 遠隔死亡ともなかった. 上行-弓部大動脈再建術における補助手段としての超低体温下循環停止法は十分な安全性を持つ有効な方法であることが示唆された.

Extra-Anatomical bypass for arteriosclerosis obliterans

Between April, 1981, and May, 1991, 40 patients underwent extra-anatomical bypass surgery for 49 lesions. Thirty-six men and 4 women with a mean age of 68 years (range 48–81) presented with symptoms of aortoiliac occlusive diseases caused by atherosclerosis. Patients were followed up for 44 months (range 1 to 121 months) after surgery. The operative mortality rate was 2.5% (1/40) and there were 4 late deaths. Hypertension, cardiac disease (history of ischemic heart disease and abnormal ECG), cerebrovascular disturbance, and diabetes mellitus were common concomitant preoperative diseases. Forty-nine percent of the limbs (24/49) were classified as Fontaine’s class II, 32.7% (16/49) as class III, and the remaining 18.4% (9/49) as class IV.Surgical procedures were axillofemoral bypasses on 53.1% of the lesions (26/49) and femorofemoral bypasses on the other 46.9% (23/49). Graft materials consisted of expanded polytetrafluoroethylene (EPTFE) (31/49), Dacron (13/49), and modified human umbilical veins (5/49).The ten-year cumulative patency rate was 95% in the femorofemoral bypass group and 88% in the axillofemoral bypass group.The anticoagulant (coumarin derivatives) was given at the first postoperative day, and it was continued as long as possible. No complications were recognized regarding this therapy. The value of the thrombo test was maintained between 20% and 40% during the follow-up period.The extra-anatomical bypass grafting was considered to be a beneficial alternative surgery to anatomical bypass in elderly and high-risk patients. Postoperative anticoagulant therapy may contribute to the patency of grafts.