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Shunji Sano

Publications and source records attributed to Shunji Sano.

51 records · Page 3Linked to original sources
PubMed2004

[Hypoplastic left heart syndrome].

Hypoplastic left heart syndrome (HLHS) is one of the last remaining problems in pediatric cardiac surgery, which necessitates a search for new solutions and continues to be a challenge for cardiologists and cardiac surgeons. The identification of HLHS in utero is extremely helpful for prompt, appropriate preoperative management. In addition, infants with prenatal diagnosis had an improvement operative mortality on Norwood operation compared to infants diagnosed postnatally. Outcome following Norwood procedure has improved significantly secondary to modifications in the surgical technique for protection of multiorgans, improved perioperative care, and improved anesthetic management. In particular right ventricular (RV)-pulmonary artery (PA) shunt using non-valved polytetrafluoroethylene (PTFE) graft was applied as a first stage palliation of HLHS to prevent hemodynamic instability associated with a classic Norwood procedure. In the modified Norwood (RV-PA shunt), higher diastolic blood pressures and lower Qp/Qs ratios that are associated with a more stable and efficient systemic circulation. In fact, patients who received a RV-PA shunt, rarely received ventilatory manipulations.

Blood Vessel Prosthesis Implantation↗
PubMed2003

Total right ventricular exclusion improves left ventricular function in patients with end-stage congestive right ventricular failure.

BACKGROUND: We developed a total right ventricular (RV) exclusion procedure for the treatment of isolated congestive RV failure. The objective of the present study was to elucidate the effects of a complete removal of RV volume overload (RVVO) on the surgically created single left ventricle (LV). METHODS AND RESULTS: Three adults (2 arrhythmogenic RV dysplasia, 1 Ebstein) and 5 children (all Ebstein) in NYHA class IV underwent the procedure. The RV free wall was resected from the heart, and the tricuspid orifice was closed. Pulmonary blood supply was obtained by a cavopulmonary connection in 6 patients and a systemic-pulmonary shunt in 2. The LV function was evaluated by 2-dimensional echocardiography 1 month after the surgery. All patients are alive. The paradoxical movement of the interventricular septum and geometry of the LV expressed by its eccentricity (2.1 to 1.2, P<0.01) were normalized after the operation in all 8 patients. LV end-diastolic volumes (59% to 109% of normal value, P<0.01), indexed maximal left atrial area (6.5 to 10.5 cm2/m2, P<0.01), LV ejection fraction (27% to 62%, P<0.01), and cardiac index (2.1 to 3.3 L/min/m2, P<0.05) all significantly increased. CONCLUSIONS: Removal of the RVVO by means of the total RV exclusion procedure provides effective volume loading, restores a cylindrical shape, and improves contractile function of the LV, thus leading to increased systemic output.

Adult↗
PubMed2003

Successful trapdoor technique for two separate coronary ostia in a single aortic sinus in arterial switch operation for complete transposition of the great arteries.

Two separate origins of coronary arteries from a single aortic sinus remains a rare but significant congenital anomaly for surgical repair. We experienced a case of a newborn with complete transposition of the great arteries with unusual coronary arteries with two separate ostia positioned close to each other in the same right aortic sinus, and the left coronary artery coursing behind the pulmonary artery. No description of this case in the English literature has been published to our knowledge. Precise anatomical diagnosis was made at operation, and these anomalous coronaries were successfully transferred by the trapdoor technique with delicate adjustment after transfer. Postoperative catheterization and angiogram done 14 months after the arterial switch operation showed no coronary artery stenosis along with normal chamber pressures. The infant is asymptomatic and shows normal development for his age.

Cardiac Surgical Procedures↗
PubMed2003

Right ventricle-pulmonary artery shunt in first-stage palliation of hypoplastic left heart syndrome.

OBJECTIVE: Pulmonary overcirculation through a systemic-pulmonary shunt has been one of the major causes of early death after the Norwood procedure. To avoid this lethal complication, we constructed a right ventricle-pulmonary shunt in first-stage palliation of hypoplastic left heart syndrome. METHODS: Between February 1998 and February 2002, 19 consecutive infants, aged 6 to 57 days (median, 9 days) and weighing 1.6 to 3.9 kg (median, 3.0 kg), underwent a modified Norwood operation with the right ventricle-pulmonary artery shunt. The procedure included aortic reconstruction by direct anastomosis of the proximal main pulmonary artery and a nonvalved polytetrafluoroethylene shunt between a small right ventriculotomy and a distal stump of the main pulmonary artery. The size of the shunt used was 4 mm in 5 patients and 5 mm in 14. RESULTS: All patients were managed without any particular manipulation to control pulmonary vascular resistance. There were 17 survivors (89%), including 3 patients weighing less than 2 kg. Two late deaths occurred due to obstruction of the right ventricle-pulmonary artery shunt. Thirteen patients underwent a stage II Glenn procedure after a mean interval of 6 months, with 2 hospital deaths. To date, a stage III Fontan procedure has been completed in 4 patients. Overall survival was 62% (13/19). Right ventricular fractional shortening at the last follow-up (3-48 months after stage I) ranged from 26% to 43% (n = 13, mean, 33%). CONCLUSION: Without delicate postoperative management to control pulmonary vascular resistance, the modified Norwood procedure using the right ventricle-pulmonary shunt provides a stable systemic circulation as well as adequate pulmonary blood flow. This novel operation may be particularly beneficial to low-birth-weight infants with hypoplastic left heart syndrome.

Blood Pressure↗
PubMed2003

In vivo monitoring of norepinephrine and its metabolites in skeletal muscle.

Although skeletal muscle sympathetic nerve activity plays an important role in the regulation of vascular tone and glucose metabolism, relatively little is known about regional norepinephrine (NE) kinetics in the skeletal muscle. With use of the dialysis technique, we implanted dialysis probes in the adductor muscle of anesthetized rabbits and examined whether dialysate NE and its metabolites were influenced by local administration of pharmacological agents through the dialysis probes. Dialysate dihydroxyphenylglycol (DHPG) and 3-methoxy-4-hydroxyphenylglycol (MHPG) were measured as two major metabolites of NE. The skeletal muscle dialysate NE, DHPG and MHPG were 11.7+/-1.2, 38.1+/-3.2, and 266.1+/-28.7 pg/ml, respectively. Basal dialysate NE levels were suppressed by tetrodotoxin (Na(+) channel blocker, 10 microM) (5.1+/-0.6 pg/ml), and augmented by desipramine (NE uptake blocker, 100 microM) (25.8+/-3.2 pg/ml). Basal dialysate DHPG levels were suppressed by pargyline (monoamine oxidase blocker, 1mM) (24.3+/-4.6 pg/ml) and augmented by reserpine (vesicle NE transport blocker, 10 microM) (75.8+/-2.7 pg/ml). Basal dialysate MHPG levels were not affected by pargyline, reserpine, or desipramine. Addition of tyramine (sympathomimetic amine, 600 microM), KCl (100 mM), and ouabain (Na(+)-K(+) ATPase blocker, 100 microM) caused brisk increases in dialysate NE levels (200.9+/-14.2, 90.6+/-25.7, 285.3+/-46.8 pg/ml, respectively). Furthermore, increases in basal dialysate NE levels were correlated with locally administered desipramine (10, 100 microM). Thus, dialysate NE and its metabolite were affected by local administration of pharmacological agents that modified sympathetic nerve endings function in the skeletal muscle. Skeletal muscle microdialysis with local administration of a pharmacological agent provides information about NE release, uptake, vesicle uptake and degradation at skeletal muscle sympathetic nerve endings.

Animals↗
PubMed2003

Acute limb ischemia does not facilitate but inhibits norepinephrine release from muscle sympathetic nerve endings in anesthetized rabbit.

Although myocardial ischemia is associated with regional cardiac sympathetic nerve deterioration, it remains unknown whether acute hindlimb ischemia impairs muscle sympathetic nerve function. In the study presented here we implanted dialysis probes in the adductor muscle of anesthetized rabbits and measured dialysate norepinephrine levels as an index of muscle sympathetic nerve activity. Acute hindlimb ischemia was induced by injection of microspheres and occlusion of the common iliac artery. Dialysate norepinephrine levels decreased from 19.3 +/- 3.5 pg/ml at control to 9.4 +/- 3.7 pg/ml at 30 min of ischemia and further to 1.7 +/- 0.2 pg/ml at 75 min of ischemia. During acute hindlimb ischemia, baroreflex (bilateral carotid occlusion) and high potassium level-induced norepinephrine response was inhibited, but tyramine-induced norepinephrine response was preserved. In conclusion, acute hindlimb ischemia caused decreases in dialysate norepinephrine levels. This reduction may be mediated by an impairment of axonal conduction and/or of norepinephrine releasing function at skeletal muscle sympathetic nerve endings.

Adrenergic Fibers↗
PubMed2003

Clusters of ventricular fibrillation in a patient with an implantable cardioverter difibrillator treated with amiodarone.

A 44 year-old man with severe left ventricular dysfunction resulting from an old myocardial infarction developed clusters of ventricular fibrillation (VF). Although coronary bypass surgery was performed and heart failure was well controlled, the VF recurred during amiodarone therapy. Despite multiple deliveries of shocks by an implantable cardioverter defibrillator, the electrical storm could not be terminated. Some substrate for rapid ventricular tachyarrhythmias, refractory to class III drugs, can lead to death from arrhythmia.

Adult↗
PubMed2002

Nicorandil ameliorates posttransplant dysfunction in cardiac allografts harvested from non-heart-beating donors.

OBJECTIVE: Warm ischemia is a major cause of cardiac allograft dysfunction in non-heart-beating donors (NHBDs). We evaluated the cardioprotective effects of nicorandil, an adenosine triphosphate-sensitive potassium channel opener, on the early posttransplant left ventricular (LV) function of hearts harvested from asphyxiated canine NHBDs. METHODS: Hypoxic cardiac arrest was induced in 12 donor dogs. In 6, nicorandil was administered intravenously at 100 micrograms/kg + 25 micrograms/kg/min after respiratory arrest and hearts were preserved with nicorandil-supplemented cardioplegic solution (nicorandil group). The remaining 6 did not receive nicorandil at any time during the experiment (control group). Hearts were orthotopically transplanted after a mean myocardial ischemic time of 4 hours. RESULTS: All 12 recipients were weaned from cardiopulmonary bypass without inotropic support. In the control group, posttransplant cardiac indices and left ventricular end-systolic pressure (LVESP) decreased significantly, while LV max-dP/dt and Tau increased over pretransplant values. No differences were seen in parameters between pretransplant and posttransplant values in the nicorandil group. Posttransplant cardiac indices, LVESP, and LV max + dP/dt were higher in the nicorandil group than in controls, while posttransplant LV max-dP/dt in the nicorandil group was lower. CONCLUSIONS: Our results indicate that pretreatment with nicorandil during hypoxic perfusion before cardiac arrest and subsequent preservation with nicorandil-supplemented cardioplegia ameliorates early posttransplant LV dysfunction of hearts harvested from asphyxiated NHBDs.

Animals↗
PubMed2002

Total right ventricular exclusion procedure: an operation for isolated congestive right ventricular failure.

OBJECTIVE: To prevent possible deleterious effects of right ventricular volume overload on cardiorespiratory function, we developed a total right ventricular exclusion procedure for the treatment of end-stage isolated congestive right ventricular failure. METHODS: Since 1996, this procedure has been performed in 5 patients in New York Heart Association functional class IV: 2 adults with arrhythmogenic right ventricular dysplasia and 3 children with Ebstein anomaly. The entire right ventricular free wall was resected along the atrioventricular groove and then parallel to the interventricular septum, sparing the pulmonary valve and a skeletonized right coronary artery. The orifice of the tricuspid valve was closed with either a polytetrafluoroethylene patch or with its leaflets. The defect of the right ventricular free wall was covered with a polytetrafluoroethylene patch in the 2 patients with arrhythmogenic right ventricular dysplasia and directly closed with the remnant of the free wall in the 3 children with Ebstein anomaly. After resection of a redundant right atrial wall, coronary sinus blood flow was rerouted into the left atrium through an atrial septal defect. A total cavopulmonary connection was constructed in 4 patients and a bidirectional superior cavopulmonary anastomosis in 1 infant. The heart was controlled with a DDD pacemaker in 3 patients. RESULTS: The patients were extubated at a mean of 14 hours postoperatively (range, 1-38 hours). There were no early or late deaths. At follow-up, ranging from 8 to 57 months, the mean cardiothoracic ratio had decreased from 74% +/- 7% before the operation to 52% +/- 6% (P <.01). All patients are in functional class I. Neither of the patients with arrhythmogenic right ventricular dysplasia have had attacks of ventricular tachycardia nor are they using antiarrhythmic medication. CONCLUSIONS: The total right ventricular exclusion procedure provides effective decompression of the lung, as well as the left ventricle, and may result in more effective volume loading of a surgically created single ventricle with increased systemic output. We believe that this new surgical option offers rescue treatment for isolated end-stage right ventricular failure in critically ill patients.

Adult↗
PubMed2002

Frequency distribution, variance, and moving average of left ventricular rhythm and contractility during atrial fibrillation in dog.

Mean levels of left ventricular rhythm and contractility averaged over arrhythmic beats would characterize the average cardiac performance during atrial fibrillation (AF). However, no consensus exists on the minimal number of beats for their reliable mean values. We analyzed their basic statistics to find out such a minimal beat number in canine hearts. We produced AF by electrically stimulating the atrium and measured left ventricular arrhythmic beat interval (RR) and peak isovolumic pressure (LVP). From these, we calculated instantaneous heart rate (HR = 60,000/RR), contractility (E(max) = LVP/isovolumic volume above unstressed volume), and beat interval ratio (RR1/RR2). We found that all their frequency distributions during AF were variably nonnormal with skewness and kurtosis. Their means +/- standard deviations alone cannot represent their nonnormal distributions. A 90% reduction of variances of E(max) and RR1/RR2 required a moving average of 15 and 24, respectively, arrhythmic beats on the average, whereas that of RR and HR required 60 beats on the average. These results indicate that a statistical characterization of arrhythmic cardiodynamic variables facilitates better understanding of cardiac performance during AF.

Animals↗
PubMedDate not supplied

Continuous cerebral and myocardial perfusion during aortic arch repair in neonates and infants.

To minimize myocardial ischemia, we repaired aortic arch obstruction with ventricular septal defect, using two different techniques of cerebral and myocardial perfusion. Seventy-one infants, ages 3 to 137 days, underwent primary repair of coarctation of the aorta (n = 49)/interruption of the aortic arch (n = 22) with ventricular septal defect. In 65 patients, an end-to-end arch anastomosis was performed with cerebral and myocardial perfusion through the innominate or the ascending arterial cannula (non-working beating heart: NWBH). In the remaining 6 patients, an arterial cannula was placed into the innominate artery. With partial cardiopulmonary bypass, the innominate artery was snared proximal to the cannulation site and the ascending aorta was cross-clamped. An extended arch anastomosis was carried out with cerebral perfusion and a working beating heart (WBH). Ten patients (15%) undergoing aortic arch repair with the NWBH technique required cardioplegic arrest to complete a proximal anastomosis, whereas in all 6 repairs with the WBH technique, the extended anastomoses were completed without myocardial ischemia. One hospital death and late death occurred, with an overall survival of 98%. End-to-end arch reconstruction is feasible without myocardial ischemia, using the NWBH technique in patients without hypoplastic arch and using the WBH technique in patients with hypoplastic arch.

Aorta↗
PubMedDate not supplied

Advantages of temporary venoatrial shunt using centrifugal pump during bidirectional cavopulmonary shunt.

Single-ventricle palliation without the use of cardiopulmonary bypass carries advantages that reduce systemic edema and inflammatory responses; however, simple clamping of the superior vena cava (SVC) without a temporary shunt leads to increase in cerebral venous pressure and subsequent decrease in cerebral blood flow during bidirectional cavopulmonary shunt (BCPS). We report our experience of BCPS, using a centrifugal pump-assisted temporary shunt. The criteria included an unrestrictive interatrial communication, the absence of atrioventricular valve regurgitation, and the existence of an antegrade pulmonary blood flow. From August 2000, 14 children with single-ventricle physiology met the criteria. The mean age was 1.0 +/- 0.9 years, and the mean weight was 8.4 +/- 2.6 kg. A temporary shunt was established between the SVC and the right atrium with right-angle cannulae, which were connected to a centrifugal pump to accelerate the blood flow from the SVC to the right atrium. All patients tolerated the procedure. Mean central venous pressure was 17 +/- 4 mm Hg, and transcutaneous oxygen saturation was maintained at 77 +/- 8% during anastomosis. No patients required blood transfusion. There were no postoperative neurological complications. The centrifugal pump-assisted temporary shunt offered safer and more effective circulatory support than other shunt systems, with excellent venous drainage in pediatric patients undergoing BCPS.

Assisted Circulation↗