Yukio Fukaya

Surgical management of left main coronary artery aneurysm

To date only 7 patients with left main coronary artery aneurysm associated with atherosclerosis have undergone surgical treatment. This report reviews a case of atherosclerotic aneurysm of the left main coronary artery with concurrent stenotic coronary artery disease that was successfully treated by direct approach to the left main coronary artery aneurysm and establishment of coronary artery bypass grafts.

Improved patency of an elastomeric vascular graft by hybridization.

A newly devised hybrid graft with high antithrombogenicity for small caliber vascular grafts was developed. The design concept was based on the incorporation of a compliant open cell structured graft, autogenous endothelial cells (ECs), and artificial basement membrane. The latter, a gel complex of type I collagen and dermatan sulfate that showed enhanced adhesion and growth of ECs but reduced platelet adhesion, was coated onto a microporous polyurethane graft (internal diameter, 3 mm; length, 4.5 cm), with near-natural compliance. Ten seeded grafts were implanted bilaterally into the carotid arteries of dogs; anticoagulant or antiplatelet therapy was not administered. This hybrid graft showed a marked improvement in patency at 1 month compared with that of simply preclotted grafts (control specimens). This result was explained by the almost complete endothelialization when the graft was implanted, a high degree of adherent strength resistance to shear stress, and a high proliferative potential. Thus, this approach of combining biomechanical and cellular engineering designs may lead to an important functional small caliber graft.

Echocardiographic diagnosis of subepicardial aneurysm ruptured into the right ventricle after inferior myocardial infarction

A subepicardial aneurysm is a rare complication of myocardial infarction that sometimes causes a left to right shunt at the ventricular level. We report on echocardiographic observations in two recent cases of inferior myocardial infarction complicated by rupture of a subepicardial aneurysm into the right ventricle (RV). Two-dimensional and color flow Doppler images in several planes offered diagnostic characteristics of the lesion, including discontinuity of the myocardium at the neck of the aneurysm, a narrow neck relative to the diameter of the aneurysm, and a back and forth flow at the neck of the aneurysm. These techniques also provided new findings, such as a two-chambered structure of the aneurysm and a circular flow pattern within the inner aneurysmal cavity. In addition, color flow Doppler imaging showed multiple shunt flows from the aneurysm to the RV. Echocardiographically diagnosed abnormalities were verified by and successfully treated with surgery in both cases. In conclusion, echocardiography with color flow Doppler imaging may have the potential to diagnose the anatomic and hemodynamic condition of a subepicardial aneurysm.

Rupture of the ascending aorta after surgical resection for lung cancer : a case report

A rupture of the ascending aorta which occurred in a woman on the 13th postoperative day following a right upper lobectomy with mediastinal lymph node dissection for lung cancer is reported herein Fortunately, the patient was rescused from a cardiac tamponade and hemothorax by emergency operation. The operative findings suggested a traumatic rupfure of the aorta, however, lymph node dissection of the mediastinum could not be excluded as a possible cause. Therefore, careful mediastinal lymph node dissection should be carefully performed in operations for lung cancer.

Combined therapies for composite graft infection after Bentall's procedure.

We present a patient who suffered from composite graft infection and mediastinitis. After replacement of the infected composite graft, in addition to administration of antibiotics, continuous irrigation of the mediastinum with solutions containing povidone-iodine and cefazolin sodium and transposition of the greater omentum were performed. His postoperative course was uneventful. Combined therapies including mediastinal irrigation and omental transposition should be considered after an operation for composite graft infection complicated with mediastinitis.

Partial resection of atrial septal aneurysm with multiple fenestrations: a case report

Aneurysms of the interatrial septum are uncommon lesions that are often accompanied by other cardiac anomalies or systemic thrombosis. The authors report 1 case of atrial septum aneurysm that was diagnosed by two-dimensional contrast echocardiography. At surgery a membrane-like, fenestrated aneurys mal protrusion to the right atrium without thrombosis was seen. The atrial septum was closed without using an artificial patch after some of the aneurysm with fenestrations was resected.

Simulation study of a selective cerebral perfusion system with a single centrifugal pump

We previously successfully developed a simple nonroller extracorporeal circulation system (NRECC). In aortic arch surgery, more than two pumps are generally used for systemic perfusion and selective cerebral perfusion (SCP); we developed a new pressure-dependent perfusion system for SCP based on our NRECC and operated by a single centrifugal pump. The cerebral perfusion line was branched from the main perfusion line, and one 15 French and two 12 French cannulae were used for SCP. The perfusion pressure was regulated with a tube occluder. Afterload was changed from 30 to 80 mm Hg, the pressure of the SCP line was increased from 80 to 200 mm Hg, and flow volume was measured. When the afterload was set at 50 mm Hg, according to the increase of perfusion from 80 to 200 mm Hg, the flow volume of the 15 French cannula increased from 280 to 950 ml/min. Under the same conditions, flow volume of the 12 French cannula increased from 160 to 560 ml/min. Sufficient flow volume of the SCP lines was obtained when the SCP line pressure was over 80 mm Hg. As a result of the increased perfusion pressure, the flow volume showed a direct increase. These findings suggest that aortic arch surgery is possible using this SCP system.

A pressure controller of selective cerebral perfusion with single centrifugal pump.

We are developing an original nonroller extracorporeal circulation system (NRECC). However, this NRECC could not perform selective cerebral perfusion (SCP). Therefore, we added cerebral perfusion lines and an automatic pressure controller to the system. The purpose of this study was to evaluate the stability and response of the pressure controller for the SCP in simulated clinical circulation. The NRECC consists of a centrifugal pump, four isolated vacuum suction lines and a conventional module. The SCP line branches from the main perfusion tubing and divides into three lines. Cerebral perfusion is regulated by a pressure controller, which is composed of an actuator, a pressure transducer, and a personal computer. The mock circuit was primed with normal saline, and the actual SCP pressure and flow were measured when the target pressure settled at 60, 80, and 100 mm Hg. The main perfusion flow was maintained at 4 L/min and the main perfusion pressure was altered from 120 to 300 mm Hg. The pressure and flow data were recorded. The SCP pressure was maintained within ±1.47 mm Hg when the set pressure was 80 mm Hg. Fluctuation of flow in the SCP line was within the range of ±2.8%. The time needed to reach the steady state pressure was 8 ± 1 seconds when the initial setting of the roller occluder was full-open, and it took only 3 ± 1 seconds to reach the next initial set pressure. We have developed the NRECC-SCP system. The SCP pressure is stable and quickly reaches steady state via the pressure controller. This system is useful for extracorporeal circulation during aortic arch operation.

Detection of skeletal muscle fatigue using an accelerometer in dynamic cardiomyoplasty

Abstract An animal experiment was done using six mongrel dogs that weighed 28 ± 3 kg to show that an accelerometer could detect skeletal muscle fatigue in dynamic cardiomyoplasty. Through left-side thoracotomy, the heart was exposed and an electrode to sense the heartbeat was positioned on the left ventricle. A left latissimus dorsi muscle flap (LDMF) was inserted into the left chest cavity and rolled around the heart. An accelerometer was put on the rolled LDMF to sense the ventricular acceleration by contraction of the LDMF and the heart. The LDMF was stimulated under these settings: pulse width, 210 μs; stimulation output, 6 V; burst frequency, 30 Hz; burst duration, 200 ms; synchronous ratio, 1 : 4; and synchronous delay, 66 ms. Output voltage from the accelerometer was recorded 1, 3, 5, 10, and 15 min after the beginning of stimulation. Percentages of the amplitude in all dogs after 3, 5, 10, and 15 min were 81 ± 10%, 63 ± 12%, 48 ± 11%, and 45 ± 14% of the values after 1 min, respectively. Significant differences were found between the values after 1 min and those after 3 min, between the values after 3 min and those after 5 min, and between the values after 5 min and those after 10 min. This study suggests that muscle fatigue is detectable with an accelerometer in actual dynamic cardiomyoplasty.

Operative Cases of the Distal Aortic Arch Aneurysm through Median Sternotomy.

1990年1月から1997年10月までに当科で手術を施行した遠位弓部大動脈瘤症例15例中, 胸骨正中切開のみで手術が可能であった7例 (男性5例, 女性2例, 年齢63歳から78歳まで, 平均年齢72.7歳) を対象とし, 術前評価による瘤の解剖学的特徴と到達法との関連性について検討した. 手術は, 全例, 中等度低体温脳分離体外循環下に弓部下行置換を施行. 手術死亡は1例で, 破裂例であった. 瘤への到達法と術前評価より得られた瘤の解剖学的特徴を検討すると, 瘤が嚢状で下行大動脈が瘤からほぼ正常な径で起始しており, 瘤の最大径が70mm以上で, 末梢側伸展度が気管分岐部近傍までであれば, 胸骨正中切開のみで手術が可能であると考えられた. また, Inclusion 法による末梢側吻合に際し, 下行大動脈起始部に3本のプレジェット付き支持糸を置いて, 牽引することでより良好な視野が確保でき, きわめて有用であった.