Yosuke Nishimura

Midterm surgical results of total cavopulmonary connection : clinical advantages of the extracardiac conduit method

OBJECTIVE We evaluated the midterm surgical outcomes of intra-atrial lateral tunnel and extracardiac conduit total cavopulmonary connection to clarify the clinical superiority. METHODS Patients (n = 167) underwent total cavopulmonary connection (88 with lateral tunnel and 79 with extracardiac conduit) from November 1991 to March 1999. Survival, incidence of reoperation and late complications, exercise tolerance, hemodynamic variables, and plasma concentration of natriuretic peptide type A were compared. In the lateral tunnel group, time-related change in lateral tunnel size was investigated for its relationship to postoperative arrhythmias. RESULTS The 8-year survival was 93.2% in the lateral tunnel group and 94.9% in the extracardiac conduit group. Seven reoperations were performed in the lateral tunnel group but none in the extracardiac conduit group. Supraventricular arrhythmias developed in 14 patients (15.9%) in the lateral tunnel group and in 4 patients (5.1%) in the extracardiac conduit group (P =.003). Freedom from cardiac-related events was 72.5% in the lateral tunnel group and 89.8% in the extracardiac conduit group at 8 years (P =.0098). Hemodynamic variables and exercise tolerance were similar in both groups but plasma natriuretic peptide type A concentration, a parameter of atrial wall tension, was higher in the lateral tunnel group. In the lateral tunnel group, intra-atrial tunnel size increased by 19.4% during the 44.2-month interval and the percent increase in tunnel size was an independent predictor of supraventricular arrhythmias. CONCLUSIONS The midterm survival, hemodynamic variables, and exercise tolerance were similar and satisfactory in both lateral tunnel and extracardiac conduit groups; however, the incidence of cardiac-related events was significantly less frequent in the extracardiac conduit group. In the lateral tunnel group, careful observation is required to monitor the relationship of the dilating tendency of the intra-atrial tunnel and the development of late complications.

Impairment of coronary flow reserve and left ventricular function in the brain-dead canine heart.

OBJECTIVE The mechanisms of cardiac dysfunction after brain death, which are thought to be mainly associated with massive catecholamine release, have not been fully elucidated, especially with respect to the coronary circulation. The aim of this study was to investigate the changes in function of the coronary artery and its contribution to hemodynamic deterioration in a canine brain death model. METHODS Brain death was induced by rapid inflation of a subdurally placed balloon catheter. Hemodynamic measurements including assessment of left ventricular contractility using pressure-volume relations and biochemical analyses of blood samples were performed in seven dogs. Coronary flow reserve in the same brain death model was assessed by changes in coronary flow and resistance induced by administering a vasodilator directly into the coronary artery in another eight dogs. RESULTS A hyperdynamic response was transiently observed after induction of brain death, followed by decreases in arterial pressure, cardiac output, and coronary blood flow. Parameters of left ventricular contractility as measured by pressure-volume relations had significantly deteriorated by 60 min after brain death. Percent changes in coronary flow by administration of acetylcholine and sodium nitroprusside were 272 and 209%, respectively, before brain death; these were decreased to 178 and 145% at 30 min after brain death, and to 192 and 153% at 60 min. Coronary resistance ratios were also significantly increased at 30 and 60 min after brain death. CONCLUSIONS Impairment of coronary flow reserve was found in the brain-dead canine heart. This impaired coronary circulation may constitute a disadvantage of prevention and recovery of cardiac dysfunction after induction of brain death.

The intra-aortic cannula pump: A novel assist device for the acutely failing heart

OBJECTIVE The intra-aortic cannula pump is a catheter pump designed to support the acutely failing heart. It expels blood from the left ventricle into the ascending aorta in a pulsatile flow pattern. The aim of the study was to analyze the hemodynamic performance of this new intracardiac support system in acute heart failure. METHODS A 24F cannula was studied in a series of 16 sheep. Hemodynamic changes were assessed in the nonfailing, the moderately failing, and the severely failing heart. Heart failure was induced by an injection of microspheres into the left anterior descending coronary artery. The cannula was inserted through the aortic arch and introduced through the aortic valve into the left ventricle. RESULTS Cannula insertion was feasible in all animals. Flow through the intra-aortic cannula flow was increased to a maximum of 3 L/min. No hemodynamic changes were observed in the nonfailing heart. A significant increase in cardiac output was observed in the moderately and severely reduced left ventricle (2.67 +/- 0.7 L to 3.51 +/- 0.83 L; P =.001; and 1.18 +/- 0.77 L to 2.43 +/- 0.44 L; P =.001, respectively). A drop in left atrial pressure was achieved in moderate and severe heart failure (14.1 +/- 5.93 mm Hg to 9.71 +/- 2.63 mm Hg; P =.0001; and 23 +/- 7.16 mm Hg to 11.2 +/- 2.55 mm Hg; P = 0.0001, respectively). Systolic and diastolic systemic blood pressures increased in the severely failing heart (57.3 +/- 12.8 mm Hg to 75.4 +/- 11.2 mm Hg; P =.0001; and 35.6 +/- 8.2 mm Hg to 60 +/- 14.3 mm Hg; P =.0006, respectively). CONCLUSIONS Hemodynamic data demonstrate the beneficial effects of the intra-aortic cannula pump in moderate and severe heart failure. The intra-aortic cannula pump represents a new modality for the treatment of acute heart failure.

Complete Resection of Thymic Sarcomatoid Carcinoma Through Total Aortic Arch Replacement.

Sarcomatoid carcinoma of the thymus is extremely rare. An operation remains the only effective treatment for this disease. We report a case of complete resection of thymic sarcomatoid carcinoma through a total aortic arch replacement and left upper lobectomy at our institution. Our aggressive operation was very effective, and the patient has experienced no recurrence in the 3 years since his operation.

Successful surgical treatment with tracheal resection for a symptomatic vascular ring in an adult

Vascular rings are congenital anomalies of the aortic arch, which may cause compression of the trachea and esophagus. Compression symptoms usually present in infants and children. Adult presentations are quite rare, and compression symptoms may not be relieved by surgical correction due to tracheal remodeling and malacia caused by a long-standing compression. Here, we present an adult case of symptomatic vascular ring formed by the right aortic arch and persistent left ligamentum arteriosus. Respiratory symptoms were predominantly due to severe tracheal stenosis caused by tracheal wall thickening through remodeling during long-standing compression, and were relieved by surgery with transection of the persistent followed by resection and reconstruction of the trachea.

Complete Resection of an Anterior Mediastinal Tumor by Total Arch Replacement and Pulmonary Artery Trunk Pasty with a Pericardial Patch: A case report

Introduction Patients with undiagnosed anterior mediastinal tumors commonly undergo surgery for diagnosis and treatment. However, determining the optimal therapeutic strategy is difficult for tumors with substantial invasion, such as lesions touching the aortic arch (AA). Case presentation A 76-year-old man of Asian descent presented to our hospital because chest computed tomography (CT) revealed an anterior mediastinal tumor. This tumor surrounded the left subclavian vein and touched the AA. We suspected the tumor to be malignant. We therefore decided to resect the tumor with preparation for total arch replacement (TAR). The operation was performed in three steps. First, we performed a mediastinal sternotomy. However, the tumor had invaded the subclavian vein, so we resected this vein after adding a transmanubrial approach. However, because of invading the AA we needed next step. Second, we shifted the patient to the right lateral decubitus position. We performed partial resection of the left upper lobe and exfoliated the distal AA. Third, we shifted the patient to the dorsal position and implanted an artificial cardiopulmonary device, after which we performed TAR, and pulmonary artery (PA) trunk plasty with a pericardial patch. The operation was successful, with no major adverse events. Pathologically, the tumor was diagnosed as diffuse large B-cell lymphoma. Discussion If oncologically complete resection is preferable for tumors with substantial invasion, complete resection should be attempted even if the surgery is difficult. Conclusion We performed complete resection of an anterior mediastinal tumor with TAR and PA trunk plasty using a pericardial patch.

Implantable Rotary Blood Pump Performs as Well as Pulsatile Pneumatic Assist Device

A new implantable rotary blood pump (the diagonal pump) was tested. Hemodynamic performance and organ perfusion were analyzed in a heart failure model and compared to the performance of a pulsatile assist device (Medos, Aachen, Germany). Six sheep were instrumented with a. 50 Fr. left atrial inflow cannula and a 16-mm Dacron outflow graft to the descending aorta. After control measurements, left ventricular heart failure was induced by intracoronary injection of microspheres. Measurements were repeated during heart failure, during mechanical support with the Medos device, and during support with the new rotary blood pump. Organ perfusion was analyzed by injection of colored microspheres. Cardiac output, arterial blood pressure, left and right atrial pressure, and first derivative of the left ventricular pressure were all significantly changed during heart failure. These parameters were restored by both types of mechanical support to exactly the same level. Organ perfusion was significantly reduced in all organs during heart failure. There was no difference in organ perfusion with the diagonal pump compared with the pulsatile Medos device. Hemodynamic status and organ perfusion due to left ventricular failure are restored in exactly the same way by a nonpulsatile miniature rotary blood pump and a pneumatic pulsatile assist device (Medos). Rotary blood pumps can be miniaturized and are therefore more attractive than pulsatile displacement pumps for long-term mechanical support.