Sukemasa Mukai

Prevention and detection of spinal cord injury during thoracic and thoracoabdominal aortic repairs

BACKGROUND Spinal cord injury is a most dreaded and unpredictable complication. In this study, based on our experimental results in dogs and early clinical results, we reviewed the incidence of paraplegia and the detection of spinal cord injury. METHODS Eighty-two patients who underwent elective surgical repair of the descending thoracic and thoracoabdominal aorta over 17 years were subjects for this study. Sixty-two patients were male and 20 were female. Their mean age was 61.6 years (range, 17 to 81 years). Monitoring somatosensory evoked potentials (SEP) and measurement of mean distal aortic pressure and cerebrospinal fluid pressure were performed perioperatively. RESULTS Sixty patients had no ischemic change in SEP. In 17 patients with significant ischemic changes of SEP, SEP recovered by increasing spinal cord perfusion pressure to more than 40 mm Hg. Two patients with complete loss of SEP experienced paraplegia. One patient had delayed paraplegia. CONCLUSIONS These results strongly suggest that SEP, mean distal aortic pressure, cerebrospinal fluid pressure should be monitored during aortic cross-clamping. Maintaining spinal cord perfusion pressure at more than 40 mm Hg by increasing mean distal aortic pressure or withdrawal of cerebrospinal fluid is valuable for preventing paraplegia.

Long-term results of mitral valve replacement: biological xenograft versus mechanical valves

Abstract We studied 279 patients who underwent mitral valve replacement at the Department of Thoracic and Cardiovascular Surgery, Hyogo College of Medicine, between November 1973 and December 1998. The patients were divided into two groups based on the type of replacement valve (154 patients in the biological xenograft group and 125 patients in the mechanical valve group), and the long-term results were compared. Clinically satisfactory results were obtained in both the biological xenograft group and the mechanical valve group according to the surgical results, long-term survival, and incidence of prosthetic valve endocarditis. At 15 years, fewer patients in the mechanical valve group than in the biological xenograft group were free of bleeding events (92.5 ± 3.7% vs 100% P < 0.05). At 15 years, the biological xenograft group was lower than the mechanical valve group with respect to freedom from thromboembolism (72.2 ± 4.6% vs 93.5 ± 3.6% P < 0.01), freedom from valve failure (22.0 ± 5.2% vs 87.0 ± 4.1% P < 0.005) and freedom from cardiac events (16.5 ± 3.9% vs 47.2 ± 14.5% P < 0.01). Though it has previously been suggested that biological xenografts used in mitral valve replacement do not need anticoagulation, the current study suggests the need for anticoagulation with the use of biological xenografts. Mechanical valves require close monitoring of anticoagulation, but their use has decreased the incidence of valve failure and thromboembolism, as compared with the use of biological xenografts. Therefore, mechanical valves are currently the preferred choice for mitral valve replacement. We believe that biological xenografts are indicated only for the older patient (≧65 years).

A case of cardiac lipoma in the ventricular septum

Lipoma in the ventricular septum is very rare. Our review of the English literature revealed that our case is the sixth of removal of lipoma in the ventricular septum. A 60-year-old male was admitted because a mass in the ventricular septum was found incidentally in abdominal CT taken following type B hepatitis. CT scanning of the heart showed 2 cm diameter of tumor in the ventricular septum. The tumor had very low radiodensity, so it was thought to be identical to fat tissue. The tumor was more clearly visualized by MR imaging and the signal intensity was high on the T1-weighted image. The tumor was suspected to be lipoma. The intraoperative histological diagnosis showed the tumor was lipoma. The tumor adhered strictly on the myocardium of the septum, and it was located near the left anterior descending coronary artery. It could not completely resected, in these reasons. Postoperative course was uneventful, and echocardiogram taken 9 months after the operation showed no evidence of enlargement of the residual tumor. It is necessary to follow-up rigidly for the potential of enlargement of the residual tumor.

Angiosarcoma of the pericardium. Review of 9 reports from Japan.

A 35-year-old woman diagnosed with a cardiac tumor by echocardiography and cinecardiography underwent surgical excision in December 1988. The port-wine tumor had invaded from the surface of the right atrium to the anterior wall of the right ventricle, preventing us from removing it completely. Pathohistologically, it was diagnosed as angiosarcoma of the pericardium. She died due to lung metastasis on the postoperative day 107. To our knowledge, only 9 such cases have been reported in Japan.

Accessory Mitral Valve Associated with Aortic Regurgitation in an Elderly Patient : Report of a Case

We encountered a 75-year-old man who complained of exertional dyspnea. An echocardiographic examination showed aortic regurgitation and a tumor in the left ventricular outflow tract. Under complete extracorporeal circulation, we surgically made an incision of the ascending aorta with a slight thickening of the aortic valve and an enlarged annulus. After excising the aortic valve, an examination of the subvalvular region revealed mitral valve-like tissue extending from the annular region of the right coronary cusp to the ventricular septum, while the chordae tendinae was attached to the septum. This issue was excised, and the aortic valve was replaced with a 27-mm SJM® valve. The postoperative course was uneventful, and the patient was discharged in good condition on postoperative day 30. An accessory mitral valve is extremely rare. Since this indication for surgical treatment is associated with congenital heart disease or a left ventricular outflow tract obstruction, most patients are young. Our patient had no associated cardiac anomalies and no pressure gradient attributable to a left ventricular outflow tract obstruction. This accessory mitral valve was discovered during aortic valve replacement surgery. To our knowledge, our patient is the oldest reported with an accessory mitral valve to have undergone a surgical resection.

Successful Conservative Treatment with Continuous Irrigation of an Electrolyzed Strong Acid Solution for Prosthetic Graft Infection of Abdominal Aorta.

腹部大動脈瘤術後人工血管感染症に対し保存的治療にて救命した1症例を経験した. 症例は65歳女性, 1996年4月2日, 腹部大動脈瘤に対し人工血管置換術を施行したが, 術後14日目の腹部CT検査にて左後腹膜腔膿瘍を認めた. 緊急再開腹術を施行, 膿瘍腔の debridement および強酸性水による持続洗浄ドレナージ術を行った. 膿汁からはメチシリン耐性黄色ブドウ球菌が検出され, バンコマイシン®, ゲンタマイシン®を投与し, 術後82日目に細菌培養検査は陰性化した. 術後144日目に退院, 3年を経過した現在も炎症所見を認めず, 外来通院中である. 腹部大動脈領域の人工血管感染症は重篤な合併症であり, 感染グラフト除去, 非解剖学的バイパス術が一般的であるが, 抗生剤やポビドンヨードを希釈した溶液による持続洗浄法により良好な結果が報告されている. 強酸性水は広い抗菌スペクトルを有し, 生体に無害な溶液であり, 同液による持続洗浄は有用であると考えられる.

A rare case of 2 free thrombi in left atrium with mitral stenosis

A 64-year-old female was admitted with general fatigue and orthopnea. Preoperative echocardiography showed a free ball thrombus in the left atrium, mitral stenosis and severe tricuspid regurgitation. To avoid a herniation of thrombus to the mitral orifice, an emergency operation was performed. Two free and small mural thrombi were found in the left atrium. Thrombectomy, mitral valve replacement and tricuspid annuloplasty were performed successfully. Postoperative course was uneventful, and she was discharged in good condition on the 21st postoperative day.