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Biomedical subjects

T Yagihara

Publications and source records attributed to T Yagihara.

At least 19 recordsLinked to original sources

Artificial chordae for mitral valve reconstruction in children.

BACKGROUND: Congenital mitral regurgitation continues to present a challenge for cardiac surgeons because of the diversity of the anatomy of the congenitally malformed mitral valve. We undertook aggressive repair of the mitral valve with artificial chordae for reconstruction of the prolapsed anterior leaflet in some children. The short-term results are reported herein. METHODS: Three patients with isolated congenital mitral regurgitation underwent mitral valve repair with use of expanded polytetrafluoroethylene sutures as artificial chordae. RESULTS: There have been no late deaths and no valve-related complications. Serial follow-up echocardiographic examinations have not revealed any increase in the severity of mitral regurgitation with continuing patient growth up to 39 months after the operation. CONCLUSIONS: When combined with other conservative methods of mitral valve repair, chordal replacement with expanded polytetrafluoroethylene sutures in children undergoing mitral valve reconstruction produces good short-term results. We believe that it delays and possibly prevents the need for a mechanical prosthesis with its associated complications in this young patient population.

Cardiac Volume

Cardiorespiratory responses to exercise after repair of the univentricular heart.

The purpose of this study is to evaluate cardiorespiratory responses to exercise in patients with univentricular heart according to the type of repair used. Forty-three patients with univentricular heart were divided into three groups: 15 preoperative patients (group A), 18 who had Fontan repair (group B) and 10 who had ventricular septation (group C). Group C was further divided into two subgroups, 7 with normal atrioventricular valve function (group C1) and 3 with atrioventricular valve regurgitation (group C2). Cardiorespiratory variables were determined after performance of cardiopulmonary exercise testing. One-hundred-and-twenty-five healthy subjects, age 5-26 years, served as controls. Oxygen uptake in group C1 at both ventilatory threshold and peak exercise was highest in all groups of univentricular heart (P < 0.05), while peak oxygen uptake in group C1 was significantly lower vs controls (P < 0.001), and that in group B was significantly higher than that for group A. Although chronotropic incompetence was noted in all groups of univentricular heart, marked improvements in both the relationship between heart rate and oxygen uptake and in the ventilatory efficiency were observed after definitive repair. While ventilatory efficiency was still impaired in group B, there was no significant difference between that in group C1 and the control group. When patients with univentricular heart of the left ventricular type (Van Praagh's type A single ventricle) were analyzed separately, superior cardiorespiratory response after ventricular septation was also found. In view of these findings, the ventricular septation procedure is preferred to the Fontan method in patients with univentricular heart when morphological conditions are suitable for this procedure so as not to make residual complications, such as significant atrioventricular valve regurgitation.

Adolescent

Pulmonary autograft implantation in the dilated aortic annulus.

The application of the pulmonary autograft (Ross) procedure in the treatment of dilated aortic annulus is still controversial, because technical errors of implantation are more likely to occur as the host annular diameter increases. The Ross procedure was successfully employed in a 28-year-old woman with a dilated aortic annulus after simple annular plication. The annulus was plicated beneath the three commissures where the pulmonary autograft was subsequently attached. The diameter of the annulus was reduced from 32 to 26 mm. This technique may provide a number of advantages compared with aortic valve replacement, especially for women of child-bearing age.

Adult

Pulmonary circulation after biventricular repair in patients with major systemic-to-pulmonary collateral arteries.

OBJECTIVE: To determine factors affecting postoperative pulmonary circulation in patients with major systemic-to-pulmonary collateral arteries. METHODS: A total of 48 patients underwent biventricular repair subsequent to unifocalization at ages in the range 1-34 years. The preparative procedures consisted of ligation of the collateral arteries in 6, plasty to the pulmonary arteries using no artificial materials in 12 and extensive reconstruction using heterologous pericardial tubes in 30. The number of the pulmonary vascular segments unifocalized was 9-18 (16 +/- 3). The amount of flow draining via residual minute systemic-to-pulmonary collaterals measured at the time of repair was 4-58% (24 +/- 16%) of the total perfusion by the cardiopulmonary bypass machine. RESULTS: This value was 40 +/- 16% in 5 patients dying in the short term after repair. The number of segments was nine or ten after unifocalization in 2 of these. Another 4 patients died in the longer term, 3 of these with CATCH 22 syndrome dying because of pulmonary hypertension. Postoperative catheterization demonstrated mean pulmonary arterial pressures in the range 8-40 (21 +/- 9) mmHg and pulmonary resistance in the range 1.7-10 (5.0 +/- 2.1) units/m2. Pulmonary resistance was correlated statistically to age at repair (r = 0.77), the number of pulmonary vascular segments (r = -0.41) and to percent collateral flow (r = 0.48). The use of a heterologous pericardial tube for unifocalization was also related probably to higher pulmonary resistance. CONCLUSION: It is essential to accomplish effective unifocalizations followed by earlier definitive repair so as to establish better pulmonary circulation.

Aorta

Effects of inhaled nitric oxide on postoperative pulmonary circulation in patients with congenital heart disease.

We studied 22 patients with residual pulmonary hypertension or symptoms of postoperative pulmonary hypertensive crisis. They received low-dose inhalation (10 ppm) of nitric oxide (NO), a selective pulmonary vasodilator, after total correction for congenital heart anomalies. Fifteen minutes of NO inhalation improved the pulmonary circulation and lessened the imbalance in the ventilation-perfusion ratio in both groups. Thus, NO inhalation is effective in the treatment of pulmonary hypertension and in the prevention of pulmonary hypertensive crises after total correction for congenital heart anomalies. All patients continued to receive NO therapeutically. The duration of such therapeutic NO inhalation was well correlated with postoperative Qp/Qs (p = 0.014) and Rp/Rs (p = 0.029).

Administration, Inhalation

Intraatrial rerouting in left isomerism and late complications.

We performed a total repair for a 1-year-old boy with left isomerism, a common atrium, incomplete atrioventricular septal defect and hemiazygos continuation. The operation performed was intraatrial rerouting with a baffle and mitral repair. The postoperative course was uneventful. However, two and a half years after the total repair, the patient revealed obstruction of the systemic atrium constructed by the baffle and the left ventricular outflow tract. Reoperation to relieve these obstructions was successful.

Cardiac Surgical Procedures

Unifocalization for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.

To extend the indications for corrective operation in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries, surgical procedures were done to unify the blood sources for pulmonary perfusion. Since December 1985, 50 patients have undergone unifocalization at ages from 2 months to 26 years with a mean of 6 +/- 7 years. In total, 84 staged unifocalization procedures and 5 other palliative procedures were done in 49 patients. These included several operative procedures: simple ligation of major aortopulmonary collateral arteries in 8; pulmonary angioplasty in 29 including reconstruction of the pulmonary arterial tree by direct anastomosis or interposition between the central pulmonary arteries and the intrapulmonary arteries; construction of artificial central pulmonary arteries with use of a xenograft pericardial tube graft in 36 with no native central pulmonary arteries detected; and construction of supplemental central pulmonary arteries also with use of a pericardial tube graft in 10. The pericardial tube graft, if used, was anastomosed to the intrapulmonary arteries on one end and connected to a prosthetic tube on the other end so as to perfuse the reconstructed pulmonary arteries. The anastomosis was made inside the lung through the divided interlobar fissure. Five patients died after operation among those undergoing these 89 preparative operative procedures. Deaths were related either to bleeding caused by anticoagulation therapy administered to prevent thrombosis within the xenograft pericardial tube graft used or to progressive congestive heart failure as a result of an excessive amount of pulmonary blood flow. Twenty-six patients have undergone intracardiac repair after previous unifocalization. In 16 patients the artificial central pulmonary arteries surgically constructed were connected to each other and then an external conduit was placed. In another patient, intracardiac repair and unifocalization could be concomitantly achieved via a median sternotomy. The right ventricle to left ventricle systolic pressure ratio immediately after intracardiac repair in 27 patients ranged from 0.24 to 0.91 with a mean of 0.54 +/- 0.17. One patient (4%) died shortly after intracardiac repair because of thrombosis within the pulmonary arteries. Postoperative catheterization showed that pulmonary vascular resistance was correlated significantly with the number of pulmonary vascular segments functioning rather than with the condition of the central pulmonary arteries. We conclude that surgical unifocalization is a feasible procedure before subsequent intracardiac repair, even in patients with critically hypoplastic or absent central pulmonary arteries.

Adolescent

Results of unifocalization for pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries: patency of pulmonary vascular segments.

Unifocalization, a surgical technique to unifocalize the pulmonary blood supply in patients with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries, is a useful preparative operation to extend the indication for corrective surgery. The preoperative and postoperative pulmonary angiograms of 51 patients (aged 3 months-26 years at first unifocalization, 29 males, 22 females), who underwent a total of 96 unifocalizations from December 1985 to July 1994, were studied to assess the effectiveness of each procedure of unifocalization. The procedures of unifocalization were ligation (9), angioplasty (6), direct anastomosis (25), bridging (6), additional central pulmonary artery creation (9), central pulmonary artery creation (36) and thrombectomy (5). Altogether 125 anastomoses were made, and the patency of 101 (80.2%) anastomoses was confirmed, 24 (19.2%) were shown to be occluded. The patency rate of the anastomoses between xenograft rolls and intrapulmonary arteries was 79.5% (70/88), while that between native central pulmonary arteries and intrapulmonary arteries was 83.8% (31/37; N. S.). The patency rate of the anastomoses involving intrahilar arteries was 88.0% (44/50), while that for the group involving extrahilar arteries only was 71.9% (46/64; P < 0.05). It is concluded that 1) unifocalization with the reconstruction of central pulmonary arteries using a pericardial roll is a useful method for patients with absent or hypoplastic central pulmonary arteries, 2) it is preferable to divide the fissures of lung in anastomosing pulmonary arteries of arborization abnormalities.

Adolescent

Surgical anatomy of the coronary circulation in hearts with discordant atrioventricular connections.

We examined the arrangement of the coronary arterial and cardiac venous systems in 46 specimens with discordant atrioventricular connections so as to identify any structural abnormalities and to consider their surgical implications in terms of anatomical biventricular repair. Grossly abnormal arterial courses were seen in 11 hearts (24%). A substantial branch supplying the morphologically right ventricular outflow tract, which could restrict a ventriculotomy, was found in 61% of cases. The coronary sinus received all the morphologically right ventricular veins, as well as the posterior interventricular vein, in 40 hearts, this pattern being in contrast to the pattern in the normal heart. The morphologically left ventricular and anterior interventricular veins, all of which drain via the coronary sinus in the normal heart, were frequently connected independently to the morphologically right atrium in the specimens with discordant connections, the drainage occurring through the spaces between the pectinate muscles. These direct drainages are at risk of potential damage either by extensive intra-atrial maneuvers or by postoperative intraatrial thrombosis. It is predicted, therefore, that surgical results can be improved still further when account is taken of this vascular anatomy of the heart itself.

Cadaver

The nature of the annular attachment of a common atrioventricular valve in hearts with isomeric atrial appendages.

OBJECTIVE: To clarify the precise anatomic arrangement of the annular attachment of a common atrioventricular valve in the setting of visceral heterotaxy. METHODS: One hundred and twelve autopsied specimens with isomeric atrial appendages were studied. RESULTS: Annular hinge points with a planar orientation were found in only 7 hearts. All others showed a nonplanar and undulating arrangement, including 7 with Ebsteins's malformation. When the posterior half of the valvar attachment was taken as a reference plane, the anterior part deviated superiorly, the distance from the plane to the anterior point being 6.7 +/- 4.9% of the circumferential length of the annulus. The ratio of the antero-posterior diameter to the width of the annulus was smaller in hearts with biventricular connections (0.77 +/- 0.15) than in those with double inlet ventricle (0.89 +/- 0.17, P < 0.001). Reflecting this, the ratio of superior deviation of the anterior valvar annulus compared to the antero-posterior diameter was greater in hearts with biventricular atrioventricular connections (P = 0.016), particularly in those with isomeric right appendages. No significant differences were found when the data was analyzed according to variations in ventricular morphology. CONCLUSIONS: The precise evaluation of the annular structure of a common atrioventricular valve may well prove to be of clinical significance so as optimally to achieve valvar annuloplasty.

Ebstein Anomaly

Surgical implications in hearts with isomeric atrial appendages.

As we have tried to demonstrate in this chapter, extensive understanding of morphology is necessary for successful definitive repair in individual patients with isomeric atrial appendages, as well as for the further evolution of optimal surgical strategies. Obviously different from patients with the usual atrial arrangement, those with isomeric atrial appendages have specific morphologic features that may underscore the clinical problems frequently found in this setting. Surgical strategies as well as individual operative procedures should be established on the basis of knowledge regarding those features presently demonstrated, namely, ventricular structures, the atrioventricular valves, the coronary circulation, and so on. Further investigations will certainly provide other aspects of which we are at present unaware.

Coronary Circulation

Use of the bidirectional Glenn procedure in the presence of forward flow from the ventricles to the pulmonary arteries.

BACKGROUND: Relative regression of the pulmonary arterial size has been reported after a conventional bidirectional Glenn procedure. Maintaining a supplemental pulmonary flow could be of surgical value unless the option also militates against the efficacy of the partial right heart bypass. METHODS AND RESULTS: Twenty-seven patients considered unsuitable for a Fontan-type procedure underwent a bidirectional Glenn procedure in the presence of forward flow from the ventricles to the pulmonary arteries, the flow being maintained through the pulmonary trunk in 22 or a systemic-to-pulmonary shunt in 5. There was one surgical death due to atrioventricular valvular regurgitation. Subsequently, 9 patients have successfully undergone a total cavopulmonary connection 2.6 +/- 1.9 years after the initial procedure. Preoperative and postoperative catheterizations revealed changes in arterial oxygen saturation (75 +/- 11% compared with 83 +/- 7%, P < .001) and end-diastolic volumes of the systemic ventricles (from 238 +/- 92% to 188 +/- 97% of the expected normal volume, P < .01), whereas no difference was detected in the mean cross-sectional area of the right and left pulmonary arteries compared with the expected normal value for the right pulmonary artery (from 76 +/- 21% to 81 +/- 20%) or in the ventricular ejection fraction (from 53 +/- 8% to 50 +/- 14%). The relative regression or growth of the pulmonary arterial size was statistically related to the size of the channel for forward flow. CONCLUSIONS: Maintenance of forward flow from the ventricle provides a feasible means, when performing a bidirectional Glenn procedure, of protecting against regression of pulmonary arterial size as well as off-loading the ventricles and improving arterial oxygen saturation.

Adolescent

Diagnosing infection of extracardiac conduit in children.

Between August 1985 and July 1992, at our center, 142 Japanese children had an extracardiac conduit operation to reconstruct the right ventricular outflow tract. The study group consisted of 22 of these 142 children who had a persistent fever and whose serum was positive for acute-phase reactants after the operation. We present the diagnostic findings for 10 children with infection of an extracardiac conduit that had been placed to restore the continuity of the right ventricle-pulmonary artery. They were part of the group of 22 children who were followed over the past 7 years with blood cultures, echocardiography, and 67Ga imaging. All 10 developed a persistent fever and were seropositive for acute-phase reactants. Conduit infection was diagnosed in only 2 patients by the detection of vegetation on echocardiography and was diagnosed in 9 of the 10 patients by an abnormal 67Ga uptake in the area of the artificial vessels used to reconstruct the pulmonary artery. The present study compared the use of blood cultures, echocardiography, and 67Ga imaging in diagnosing an infection of the extracardiac conduit. The sensitivity of blood cultures in diagnosing an extracardiac conduit infection was 70% (7/10), and the specificity was 92% (1/12). 67Ga imaging showed a higher sensitivity than echocardiography in diagnosing infection of an extracardiac conduit.

Acute-Phase Proteins