Kunio Asada

Angiotensin II receptor antagonist, L-158,809, prevents intimal hyperplasia in dog grafted veins.

We investigated the levels of the angiotensin II-forming enzymes, chymase and angiotensin converting enzyme (ACE), in dog grafted veins, and studied the effect of an angiotensin II type 1 receptor antagonist, L-158,809, on vascular proliferation in the grafted veins. The right external jugular vein was grafted to the ipsilaterial carotid artery. In the group treated with L-158,809, the drug (10 mg/kg per day, p.o.) were administered orally from 7 days before the operation to 28 days after it, while the others were administrated placebo. In the placebo-treated group, the chymase activity in the grafted veins was increased about 10-fold and the ACE activity was doubled. The areas of intima and media were significantly increased in the grafted veins in the placebo-treated group. L-158,809 significantly reduced the intimal area of the grafted veins. An angiotensin II receptor antagonist, L-158,809, prevented the vascular proliferation in the grafted veins, and the development of the proliferation may depend on activation of local angiotensin II formation.

Right ventricular myxoma: report of a case.

We herein report a 36-year-old man who underwent surgical resection for myxoma. Preoperative two-dimensional echocardiography demonstrated a mass in the right ventricle. Intraoperatively, the tumor was found to derive from an anterior papillary muscle of the tricuspid valve. The tumor was successfully excised and the tricuspid valve was repaired with chordoplasty and annuloplasty. A histopathological examination revealed myxoma and a 2-year follow-up has shown no evidence of recurrence or tricuspid valve regurgitation.

Neuroleptic malignant syndrome following cardiac surgery: successful treatment with dantrolene

Neuroleptic malignant syndrome (NMS) is a rare idiosyncratic reaction to neuroleptic drugs, which is potentially fatal. It has been occasionally reported that NMS occurs subsequently after surgery. We report a case of a 53-year-old male patient who developed NMS following cardiac surgery due to the resumption of zotepine. The patient was attacked with hyperthermia, sweating, significant shivering, trembling of the fingers, disturbed consciousness and extreme muscle rigidity after the resumption of zotepine. Furthermore, laboratory measurements revealed increased levels of serum blood urea nitrogen, creatinine and creatine phosphokinase. In addition, elevation in white blood cell counts and myoglobinemia were also observed. After a diagnosis of NMS was established, administration of zotepine was stopped and treatments with administration of dantrolene and a large amount of fluid infusion intravenously were started. Following these treatments, the clinical symptoms subsided and the laboratory findings improved without need for hemodialysis. Dantrolene, which is able to effectively impede the abnormal flow of calcium from the sarcplasmic reticulum into the muscle cytoplasm, was beneficial to reduce the clinical symptoms of NMS. We hereby present a patient with NMS following cardiac surgery, and discuss its subsequent management.

Left atrial free-floating ball thrombus with recent cardioembolic stroke

A 67-year-old man was admitted to a local hospital complaining of hemiparesis. Because of coexisting arrhythmia, he was examined by echocardiography and found to have an oval free-floating thrombus in the left atrium concomitant with mitral and aortic stenosis. He was transferred to our hospital for emergency surgery. He underwent an operation on the ninth day from the onset of neurological dysfunction, when a 2.5 x 2.5 x 3.0 cm ball thrombus was removed, and the diseased mitral and aortic valves were replaced. His postoperative course was uneventful, with no neurological sequelae. Though left atrial ball thrombus is rarely found in patients with mitral valve disease, when it is found, then immediate surgical intervention is recommended to avoid sudden death. However, there is a high risk that any cerebral lesion may worsen due to systemic heparinization. Therefore, the optimal time of surgery in a patient with a recent neurological deficit is controversial.

Removal of the endocardial pacemaker leads —Experience with 16 leads in 10 patients—

Recent advances in pacemaker leads have contributed to the improvement of their stability at the anchored sites. However, we sometimes have difficulty in removing them. We have experienced the removal of 16 leads in 10 patients (male: 7, female: 3) in the last 5 years. The age of patients ranged from 48 to 87 years, and the average was 60. The reasons for the removal were as follows; pocket infection in 6 cases, sepsis in 1 case, ischemic skin erosion in 1 case, retained fractured ventricular lead in 1 case, fracture of Accufix atrial lead in 1 case. The methods of removal consisted of using the removal kit, the snare or the basket snare transvenously, direct surgical approach or a combination of them. We used the removal kit alone in 12 electrodes (6 atrial, 6 ventricular), and removal of 5 atrial and 3 ventricular leads were successfully by this method only. The removal of 4 leads by kits alone failed, so that 2 ventricular leads were removed transvenously, one atrial and one ventricular lead were removed surgically, and 1 ventricular lead was left untreated. Finally, we were able to remove 15 of 16 leads (93.3%) successfully. This experience indicates that these interventions should be performed as less invasively as possible, yet we should give an explanation to the patients as to the options we may employ when we have failed in the intended procedure.

A case report of infective endocarditis caused by MRSA and characterized by pedicled vegetation on the posterior wall of left atrium

We report here a case of active infective endocarditis caused by Methicilin-Resistant Staphylococcus aureus (MRSA). A 24-year-old woman was admitted to the Osaka Medical Collage Hospital with continuous fever. After admission, MRSA was detected by blood culture and chemotherapy with Vancomycin was started. However, after 1 week, her condition had not improved. Moreover, a pedicled vegetation on the posterior wall of the left atrium and mitral regurgitation due to prolapse of the anterior leaflet were revealed by transesophageal echocardiography. The vegetation grew to about 2 cm in diameter and prolapsed into the left ventricle during diastole. We performed an early operation although the infection was still active due to its rapid growth and the risk of embolism. There was a large pedicled vegetation on the posterior wall of the left atrium as shown by preoperative echocardiography, but the mitral valve appeared to be intact. Therefore, the vegetation was completely removed and the mitral annulus was plicated by Kays method to treat the associated mitral regurgitation. Postoperatively, we administered VCM 2 g/day for 24 days. The course was uneventful. The patient was discharged from the hospital on the 31st postoperative day.

Augmentation of coronary bypass graft flow induced by dipyridamole and its relation to bypass graft patency

To evaluate the effect of dipyridamole on coronary bypass graft flow, 10 mg of dipyridamole was injected intravenously, during the measurement of graft flow, at the time of surgery. Its concentration in serum was measured and compared with that after oral administration. In 50 individual vein grafts performed on 35 patients, graft flow increased from 65 ±37 to 96±55 ml/min (p<0.001) after the dipyridamole injection and the arterial pressure decreased slightly. In 40 grafts whose graft flow was increased by more than 10 ml/min by dipyridamole, the patency rate (at 5 weeks) was 98 per cent, whereas that of the 10 other grafts, which responded poorly, was only 50 per cent (p<0.01). The serum concentration of dipyridamole, 3 minutes after intravenous injection, was 1.46±0.68 μg/ml, while the level of orally administrated dipyridamole, in 3 groups of patients who were given 50 mg, 75 mg and 100 mg, three times a day, respectively, was steady, being 0.68±0.20 μg/ml, 1.43±0.41 μg/ml and 1.73±0.50 μg/ml, 2 hours following ingestion. We concluded that intravenous dipyridamole increases the graft flow and that a better patency is obtained in those grafts in which the graft flow is increased by more than 10 ml/min. It is also expected that routine doses of oral dipyridamole possibly increase the graft flow after coronary bypass surgery.

Intrathoracic Prosthetic Graft Infection Caused by MRSA.

人工血管にMRSA感染を生じ, 治療に難渋した症例を経験したので, 文献的考察を加えて報告する. 症例は62歳の女性. 真性の胸部下行大動脈瘤に対し1990年11月27日人工血管置換術を施行したが, 1992年3月喀血をきたした. グラフト遠位吻合部の出血が肺に穿通したものと診断し, 4月に吻合部の切除, 再置換術と左肺下葉合併切除を施行した. 吻合部よりMRSAを検出し, 胸腔内洗浄にもかかわらず2週間後に再度遠位吻合部の縫合不全による出血をきたした. 上行大動脈-腹部大動脈バイパスを作成したのち, 2回目の手術で用いた人工血管を除去し, 大網充填を行った. しかし同年8月に, 初回手術後残存していた大動脈グラフト近位部にも縫合不全による出血をきたしたので, 遺残人工血管を除去し, 大動脈を左総頸動脈末梢で縫合閉鎖した. イソジンによる胸腔洗浄でMRSAは陰性化し, 軽快退院した.