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Biomedical subjects

Mitsuru Aoki

Publications and source records attributed to Mitsuru Aoki.

14 recordsLinked to original sources

Successful extensive enlargement of a non-committed ventricular septal defect in double outlet right ventricle.

We performed an arterial switch operation in a patient with double outlet right ventricle with non-committed ventricular septal defect, and abnormal insertion of the tension apparatus of the tricuspid valve which produced moderate tricuspid regurgitation. This required extensive enlargement of the ventricular septal defect between the attachments of the cords of the tricuspid valve so as to create the interventricular rerouting that made possible the arterial switch operation. Postoperatively, we produced a straight, unobstructed, left ventricular outflow tract, improved the extent of tricuspid regurgitation, and achieved low right atrial pressures. Enlargement of the interventricular communication can set the scene for biventricular repair in this particular subset of patients with both arterial trunks arising from the morphologically right ventricle.

Abnormalities, Multiple↗

Establishing right ventricle-pulmonary artery continuity by autologous tissue: an alternative approach for prosthetic conduit repair.

BACKGROUND: In conventional conduit operations, longevity has been essentially limited by the inevitable need for conduit replacement. This study was undertaken to compare long-term results of the use of equine pericardial conduits, autologous pericardial conduits, and direct anastomosis repair. METHODS: Between 1982 and 2001, 366 patients underwent primary establishment of right ventricle-pulmonary artery continuity at our institution. The mean age at the time of operation was 6.2 years (range, 4 days to 28 years) and mean weight was 17.2 kg (range, 1.6 to 61 kg). Three different repair techniques were used for connection: hand-made valved equine pericardial conduits (n = 179), autologous pericardial conduits (n = 71), and direct anastomosis without a conduit (n = 116). Mean follow-up period for early survivors was 8.6 years in the equine group, 6.1 years in the direct anastomosis group, and 5.1 years in the autologous pericardium group. RESULTS: Direct anastomosis repair (p = 0.0002) was associated with significantly better freedom from late events (conduit replacement or late death) than equine pericardial conduits. The hazard ratio was less with the autologous pericardium conduit than with the equine pericardium, but the difference was not statistically significant (p = 0.2122). Younger age at operation, and postoperative pressure ratio from right to left ventricle were also predictors of conduit longevity. CONCLUSIONS: To decrease the probability of late events, direct anastomosis is an encouraging technique compared with traditional equine pericardium extracardiac conduit repair. An autologous pericardial conduit, because of its benefits, would be an alternative when direct anastomosis is not suitable.

Adolescent↗

The influence of pH strategy on cerebral and collateral circulation during hypothermic cardiopulmonary bypass in cyanotic patients with heart disease: results of a randomized trial and real-time monitoring.

OBJECTIVE: The optimal pH strategy during hypothermic cardiopulmonary bypass remains controversial. Systemic pulmonary collateral circulation may develop in patients with cyanotic anomalies. The purpose of this study was to evaluate the effect of pH strategies on cerebral oxygenation and systemic pulmonary collateral circulation during hypothermic cardiopulmonary bypass in cyanotic patients with heart disease. METHODS: Forty cyanotic patients (age > 1 year) with heart disease were prospectively randomized into 2 groups. Group 1 (n = 19, 14.3 +/- 1.5 kg) underwent hypothermic cardiopulmonary bypass with alpha-stat strategy and group 2 (n = 21, 12.5 +/- 0.9 kg) with pH-stat. Cardiopulmonary bypass was established with pump-assisted drainage. Cerebral oxygenation was assessed by near-infrared spectroscopy and the systemic pulmonary collateral circulation was calculated by pump flows [% systemic pulmonary collateral circulation = perfusion flow - drainage flow)/perfusion flow x 100]. Lactate was measured as an index of systemic anaerobic metabolism. RESULTS: There were no significant differences in preoperative hematocrit, oxygen saturation, Qp/Qs, cardiopulmonary bypass duration, minimum temperatures, perfusion flow and pressure, urine output, and depth of anesthesia between the groups. Oxyhemoglobin signal and tissue oxygenation index of near-infrared spectroscopy monitoring were significantly lower in group 1 compared with group 2 (P =.008 and P <.0001, respectively), suggesting inadequate cerebral oxygenation with alpha-stat. Deoxygenated hemoglobin signal was significantly higher in group 1 relative to group 2 (P <.0001). The % systemic pulmonary collateral circulation was significantly lower in group 2 compared with group 1, suggesting a reduced pulmonary collateral circulation with pH-stat (P <.0001, average; group 1, 20.1% +/- 1.2%; group 2; 7.7% +/- 0.7%). Serum lactate was significantly lower in group 2 (P <.0001). CONCLUSIONS: The pH-stat strategy results in an improved environment, including sufficient cerebral oxygenation, decreased systemic pulmonary collateral circulation, and lower lactate level during hypothermic cardiopulmonary bypass in cyanotic patients with heart disease. Future studies should investigate the long-term neurological outcome.

Analysis of Variance↗

Double switch operation in a young infant.

We performed a combined Senning and arterial switch operation on a 2-month-old patient with congenitally corrected transposition, Ebstein's malformation producing severe tricuspid regurgitation, ventricular septal defect, pulmonary hypertension, and congestive heart failure. The tricuspid regurgitation was improved. The double switch operation has the advantage of improving the function of the systemic atrioventricular valve, especially in newborns or young infants in whom the outcome of the valvar repair is poor.

Cardiac Surgical Procedures↗

Midterm results of surgical treatment of systemic ventricular outflow obstruction in Fontan patients.

BACKGROUND: Achieving unobstructed blood flow from the systemic ventricle to the aorta is important during the Fontan procedure for complex cyanotic congenital heart disease when there is systemic ventricular outflow obstruction (SVOO). Because SVOO can progress after the Fontan procedure if there is morphologic obstruction, we have adopted a policy of relieving obstructions to systemic blood flow. METHODS: Twenty-five patients were treated by the Fontan procedure with SVOO. Twenty-one patients had undergone prior pulmonary artery banding and 10 patients had undergone prior arch repair. Systemic ventricular outflow obstruction progressed in 5 patients after the Fontan procedure. Main diagnosis was single ventricle in 12, tricuspid atresia in 5, transposition of the great arteries in 4, double-outlet right ventricle in 3, and common atrioventricular canal in 1. Mean age at operation was 6.5 years (range 1 to 15 years) and the average preoperative pressure gradient across the ascending aorta and systemic ventricle was 29 mm Hg (range 0 to 100 mm Hg). The Damus-Kaye-Stansel procedure was performed in 18 patients (double-barrel anastomosis in 13, end to side anastomosis in 5), and subaortic resection or ventricular septal defect or bulboventricular foramen enlargement was performed in 7. Double-barrel anastomosis has been our first choice since 1994, if the pulmonary valve is intact. Follow-up has ranged from 4 months to 14 years (average 5.0 years). Twenty-three of the 25 patients have undergone recatheterization (average 21.4 months later). RESULTS: No early deaths were found; one late death was reported of a patient with single right ventricle (4.0%). The postoperative average pressure gradient was 1.1 mm Hg (0 to 10 mm Hg), and the average right atrial pressure was 14 mm Hg (9 to 20 mm Hg). In all patients who underwent ventricular septal defect or bulboventricular foramen enlargement, regular sinus rhythm was maintained postoperatively. Regarding the Damus-Kaye-Stansel procedure, there was minimal progression of semilunar valve insufficiency except in 1 patient who underwent end-to-side anastomosis with moderate pulmonary regurgitation postoperatively. CONCLUSIONS: The midterm results of the Fontan procedure with SVOO have been satisfactory. Because SVOO might progress after the Fontan procedure if there is morphologic obstruction, an appropriate strategy to relieve obstruction to systemic blood flow should therefore be performed concomitantly with the Fontan procedure.

Adolescent↗

Effects of autologous platelet concentrate reinfusion after open heart surgery in patients with congenital heart disease.

BACKGROUND: Plasma pheresis and reinfusion of platelet-rich plasma has not been shown to reduce blood loss in cardiac patients. Recently, freshly prepared autologous platelet concentrates (PC) can be made from patient's blood and has a higher concentration than conventional platelet rich plasma. In this study, the effects of autologous PC reinfusion were examined after open heart surgery in patients with congenital heart disease. METHODS: Eight patients with noncyanotic congenital heart disease, who underwent open heart surgery and reinfusion of autologous PC, were classified as the PC group. Eight other patients with noncyanotic congenital heart disease, who underwent only open heart surgery, were defined as the control group. Ages ranged from 2 to 24 years and were not significantly different between the two groups (9.3 +/- 5.1 years in the PC group and 12.6 +/- 7.9 years in the control group, p = 0.33). In the PC group, blood was collected from the femoral vein through a 6F catheter introducer; 9 to 20 U (13.0 +/- 5.4 U, 0.42 +/- 0.22 U/kg) of autologous PC were prepared and were reinfused after protamine administration. The time course of platelet counts was examined until postoperative day 7. Aggregation responses to adenosine diphosphate; (4 micromol/L and 8 micromol/L), collagen (1 micromol/L and 5 micromol/L), and epinephrine (5 micromol/L and 10 micromol/L) were evaluated after induction of anesthesia (individual references), after protamine administration, at the end of the operation; these responses were shown as recovery ratios. RESULTS: Blood loss during surgery in the PC group was significantly less than in the control group (4.8 +/- 3.0 mL/kg versus 7.8 +/- 1.7 mL/kg, p = 0.044). Similarly blood loss on postoperative day 1 in the PC group was significantly less than in the control group (3.6 +/- 1.2 mL/kg versus 7.2 +/- 3.1 mL/kg, p = 0.013). The platelet counts in the PC group were larger than those in the control group until postoperative day 5, after reinfusion of prepared autologous PC. The recovery ratios of the aggregation responses to adenosine diphosphate, collagen, and epinephrine after protamine administration were not significantly different between the two groups. However, recovery in the PC group after reinfusion of the prepared autologous PC was greater than in the control group. CONCLUSIONS: Reinfusion of the freshly prepared autologous PC was followed by good aggregation responses and low blood loss in patients with noncyanotic congenital heart disease after open heart surgery. This procedure may be useful in pediatric open heart surgery without blood transfusion or with little administration of homologous blood products.

Adenosine Diphosphate↗

Effects of dilutional and modified ultrafiltration in plasma endothelin-1 and pulmonary vascular resistance after the Fontan procedure.

BACKGROUND: Pulmonary vascular resistance (PVR) is closely related with patients' hemodynamics after the Fontan procedure and endothelin-1 (ET-1) may play an important role in pulmonary circulation. Modified ultrafiltration (MUF) is known to remove inflammatory mediators after cardiopulmonary bypass (CPB) surgery. The time courses of plasma ET-1 and PVR were examined before and after the Fontan procedure with MUF. METHODS: Twenty-two patients who underwent the Fontan procedure were divided into two groups: a dilutional ultrafiltration/modified ultrafiltration (DUF/MUF) group (n =11) and a control group (n = 11). Conventional ultrafiltration was performed during CPB in the control group. DUF was performed semicontinuously during CPB and MUF was continued until 15 to 20 minutes after the CPB with polyacrylonitonile membrane in the DUF/ MUF group. The plasma ET-1 concentration was measured before and after CPB, after MUF in the DUF/MUF group, and 6 and 24 hours after CPB. PVR was calculated simultaneously using a thermodilutional catheter. RESULTS: Plasma ET-1 levels increased significantly after CPB in the control group but they did not increase immediately after CPB in the DUF/MUF group. Similarly, PVR increased significantly after CPB in the control group but it did not increase after CPB in the DUF/MUF group and remained low at 6 and 24 hours after CPB. CONCLUSIONS: DUF and MUF suppress the increase in the plasma ET-1 concentration that occurs immediately after the completion of the Fontan procedure and may be an effective intervention for maintaining low PVR after the procedure.

Cardiopulmonary Bypass↗

Valvular repair for atrioventricular regurgitation in complex anomalies in modified Fontan procedure with reference to a single ventricle associated with a common atrioventricular valve.

Between January 1985 and October 1998, 169 of 372 patients who underwent a modified Fontan procedure had atrioventricular valve regurgitation (AVVR) that ranged in degrees from 1 to 4. Concomitant repair for AVVR was performed in the majority of cases. All but 12 patients had the AV valve repaired, mainly by circular annuloplasty; none had valve replacement. Although mortality was significantly higher in the AVVR cases (21 of 169 [12%]) than in the cases without AVVR (eight of 203 [3.9%]; P <.007, chi-square), actuarial survival in the AVVR cases was 83% at 5 years, 81% at 10 years, and 73% at 12 years. The degree of AVVR before surgery was 1.62 +/- 0.73 on average; 82 cases had more than grade 2 regurgitation. There was a significant decrease to 0.54 +/- 0.61 (P <.0001) after surgery in long-term survivors. Cases with AVVR can be treated with reasonable risk provided proper repair of the valve is performed. Circular annuloplasty is a simple and uniformly effective method with which to control regurgitation, even for the common AV valve. Copyright 1999 by W.B. Saunders Company

Journal Article↗

Lack of opiate effects on cat C polymodal nociceptive fibers.

The direct application of preservative-free morphine sulfate (1.5%, 1 ml, 19.8 mumol) or fentanyl (0.06%, 1 ml, 1.07 mumol) on the superficial radial or saphenous nerve of cats did not alter the response of single C polymodal nociceptive fibers (PMNs) to noxious radiant heat stimulation of their peripheral receptive fields. Intravenous administration of fentanyl (100 or 200 micrograms/kg, 0.179 or 0.358 mumol/kg) also showed a similar lack of effect on the radiant heat evoked responses of single PMNs. Slight changes in the mean latencies following drug administration were recognized, which were not statistically significant. The use of morphine (1.5%, 1 ml, 19.8 mumol) with preservatives (chlorbutanol 0.5% and sodium bisulfite less than 0.1%) caused conduction block of PMNs within 6-15 min. Subsequent washout of the drug resulted in the return of the unitary discharges within 8 min. Lidocaine (0.25 and 0.5%, 10.7 mumol and 21.4 mumol) caused conduction block within 5-18 min. These data support the classically held concept that opiates, in clinically useful concentrations, do not alter peripheral nerve function.

Action Potentials↗

Autopericardial patch tracheoplasty for tracheal stenosis after arterial switch operation.

Though congenital tracheal stenosis in infants with congenital heart disease is uncommon, congestive heart failure is often deteriorated by respiratory symptoms. We report an infant having a diagnosis of congenital tracheal stenosis complicated with congenital heart disease who underwent pericardial patch tracheoplasty after the arterial switch operation for the transposition of the great arteries. External appearance of the trachea showed no stenosis and tracheal rings were well formed. Intraoperative bronchofiberscopy transilluminated the upper border of stenosis. The trachea was opened longitudinally to the extent of 30 mm to the point from 10 mm point proximal to the bifurcation. The incision was enlarged with the autologous pericardial patch using running absorbable suture. Then pericardial patch was anchored at several points to the posterior surface of the ascending aorta, innominate artery, and to the strap muscles of the neck. He is doing well now without any respiratory symptom.

Absorbable Implants↗