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Biomedical subjects

I S Chiu

Publications and source records attributed to I S Chiu.

At least 19 recordsLinked to original sources
PubMed2001

Validation of pulmonary venous obstruction by electron beam computed tomography in children with congenital heart disease.

The purpose of this study was to explore the useful imaging findings of electron beam computed tomography (EBCT) for diagnosing pulmonary venous obstruction (PVO) in children with congenital heart disease. From July 1995 to March 1998, 17 children (9 girls and 8 boys, aged 7 days to 14 years and 9 months [median 3 months]) with the diagnosis of PVO were enrolled in this study. All images were obtained by EBCT at the end-diastolic phase of the cardiac cycle after administration of intravenous iodinated contrast medium. The findings of 25 EBCT studies were retrospectively analyzed by 2 radiologists and were correlated with echocardiography, angiocardiography, and surgical findings. Main findings on EBCT for PVO were (1) structural narrowing, (2) thickened interlobular septa, (3) peribronchovascular cuffing, and (4) ground-glass opacity of the alveoli. Structural narrowing along the course of the pulmonary venous drainage was the most important finding in all examinations (25 of 25). Lung parenchymal changes secondary to PVO included thickened interlobular septa (17 of 25), peribronchovascular cuffing (15 of 25), and ground-glass opacity of the alveoli (8 of 25). Thus, the combination of these findings provides very useful data for the definitive diagnosis of PVO. Characteristic electron beam computed tomographic findings can validate suspected PVO noninvasively.

Adolescent↗
PubMed2001

Balloon angioplasty for obstructed modified systemic-pulmonary artery shunts and pulmonary artery stenoses.

OBJECTIVES: The results of percutaneous balloon angioplasty for obstructed modified Blalock-Taussig (BT) or central shunts and pulmonary artery (PA) stenoses were studied to assess its role as an alternative to second shunt and surgical PA angioplasty. BACKGROUND: Obstruction of a modified shunt and PA stenosis related to the shunt or ductus are not infrequent. A second shunt with or without PA angioplastv is required if the PA size, morphology or age of the patient is suboptimal for definitive surgery. METHODS: From June 1994 to May 1999, balloon angioplasty for obstructed systemic-to-PA shunts was performed in 46 patients, with ages ranging from 1 month to 7.4 years (2.2 +/- 1.9 years). Among the 46 patients, 32 had modified BT shunts, 5 had bilateral shunts, 7 had modified central shunts, and 2 had both modified BT and central shunts. Stenoses were seen in 27 main branch PAs, and interruption was present in three. A concurrent balloon angioplasty was attempted in 28 main branch PAs, but it was performed in only 25 vessels. RESULTS: Balloon dilation for obstructed modified shunts was considered to be effective in 42 patients (91%), while angioplasty for PA stenosis was effective in 14 vessels and not effective in 11 vessels. After balloon dilation angioplastv, oxygen saturation in the aorta increased from 74.4 +/- 4.3% to 80.8 +/- 3.6% (p < 0.01) in these 46 patients. One patient died of pneumonia. Eight patients required an additional modified BT shunt soon after the procedure because of severe stenosis or interruption at main branch PA. After a mean follow-up period of 11.6 +/- 5.4 months, 29 patients underwent a repeated imaging study to evaluate the morphology and size of the PAs. Of these 29 patients, 26 underwent open-heart surgery, with two mortalities. CONCLUSIONS: When a second shunt is under consideration because of obstruction of the modified shunt, balloon angioplasty is a possible alternative procedure. Pulmonary artery stenosis, if present, can be simultaneously dilated.

Angioplasty, Balloon↗
PubMed2001

A minimal transverse incision with low median sternotomy for pediatric congenital heart surgery.

OBJECTIVES: Median sternotomy is the incision of choice for most cardiac surgical procedures, but the full-length vertical skin incision generally leaves an unsightly scar. In certain patients undergoing short, low-risk procedures, cosmetic considerations are of relatively greater importance. METHODS: A minimal transverse curvilinear skin incision with low median sternotomy is described which gives adequate exposure for selected open-heart procedures. Since September 1997, this approach has been used in 22 pediatric patients undergoing open-heart surgery including five cases of Fallot's tetralogy. We also compared the operation time and result with other approaches. RESULTS: Using this modified method, the exposure of the heart was good enough, and there were no difficulties in cannulating the ascending aorta for cardiopulmonary bypass. Although it took a longer time to close the wound, the operation time was similar to the standard approach. The small transverse wound was not visible under conventional clothes. CONCLUSIONS: A minimal transverse incision with low median sternotomy provides an alternative approach for small wound open-heart surgery in patients with a simple congenital cardiac defect. It is technically feasible and has a good cosmetic result.

Adolescent↗
PubMed2001

Comparison of pulmonary arterial flow phenomena in spiral and Lecompte models by computational fluid dynamics.

OBJECTIVES: The transposed great arteries are simply reversed by means of a conventional arterial switch operation with the Lecompte maneuver without resumption of their spiral relationship. We seek to clarify the functional implications of the spiral relationship of the great arteries by means of mathematic modeling. METHODS: Computational fluid dynamics is used to compare flow phenomena of the spiral and Lecompte (nonspiral) models under various body surface areas. RESULTS: The velocity profile and wall-shear stress distribution are more uniform for the spiral than for the Lecompte model. The pressure drop and power loss ratio are smaller for the spiral than the Lecompte model for all the body surface areas investigated. The power loss ratio increases abruptly starting from 0.43 m2 of body surface area for the Lecompte model. At that specific stage, after arterial switch operation with the Lecompte maneuver, suprapulmonary stenoses occur most frequently. CONCLUSIONS: Reconstructing the great arteries in spiral fashion might be recommended because the blood flow patterns are more streamlined than those of the Lecompte maneuver. Initiation of stenosis might be minimized to some extent.

Angiography↗
PubMed2001

The assessment of the proximal left pulmonary artery by transesophageal echocardiography and computed tomography in neonates and infants: a case series.

IMPLICATIONS: Transesophageal echocardiography (TEE) is often used during surgical repair of congenital heart disease. In our case series of 256 newborns and infants, we found that a left paracarinal view of TEE could visualize the proximal left pulmonary artery, a frequent blind spot for TEE, in most patients, except in a few cases with anatomic variations of the esophagus in the right lateral to the vertebra.

Cardiac Surgical Procedures↗
PubMed2001

Preoperative diagnosis by electron beam computed tomography and perioperative management of primary tracheal anomalies in tetralogy of Fallot.

PURPOSE: To investigate the usefulness of electron beam computed tomography (EBCT) in the preoperative detection and perioperative management of insidious concomitant primary tracheobronchial anomalies in patients with tetralogy of Fallot (TF). METHODS: From July 1995 to October 1999, 88 children (38 girls, 50 boys) with TF were enrolled in this study. EBCT examinations provided information needed to plan management. The final diagnoses of airway abnormalities were correlated with the findings of bronchoscopy in five patients and confirmed during surgery. RESULTS: Fourteen (16%) of the 88 patients had associated primary tracheobronchial anomalies. Nine patients had tracheal bronchi, which were combined with tracheobronchial stenosis in two patients and with tracheal stenosis in one patient. Two patients had tracheal diverticulum, which was combined with lower tracheal stenosis in one patient. Two patients had congenital tracheal stenosis. Tracheomalasia was found in one patient. Three patients with ventilation difficulties died postoperatively. Special attention was given to the care of the diseased airways perioperatively, and the remaining 11 patients had a smooth course of hospitalization and discharge. CONCLUSIONS: Our results show that EBCT provides good delineation of both cardiac and tracheobronchial anomalies and suggest that it should be used perioperatively to detect associated airway anomalies in TF, to facilitate the design of an appropriate ventilation care strategy.

Adolescent↗
PubMed2001

Combined atrial and arterial switch operations for congenitally corrected transposition.

Conventional repair of congenitally corrected transposition of the great arteries (CCTGA) is directed at eliminating the associated defects and leaves the right ventricle in a systemic position. The long-term outcome of this procedure may involve deterioration of right ventricular function with tricuspid regurgitation and failure of the conduction system. We describe two consecutive patients with CCTGA, one of whom had apicocaval juxtaposition. The patients were aged 19 and 16 months, respectively, and both underwent a combination of atrial and arterial switch. These are the first two reported cases of successful completion of this type of operation in Taiwan. Our review of previously reported cases suggested that no significant difference exists in the outcome of patients with this condition who undergo either arterial switch or Rastelli-type repair plus atrial redirection. However, reported patients who underwent anatomic repair had lower early mortality, late mortality, and incidence of complete heart block than those who underwent conventional repair. The present two cases and our review of the literature suggest that, among patients with apicocaval juxtaposition, 1) Mustard operation is optimal for patients with small atrial volume; 2) one-and-one-half ventricular repair may be helpful to the outcome, especially when treatment is combined with Rastelli-type repair; and 3) excellent access to the ventricular septal defect through the tricuspid valve is afforded via a left atriotomy. From the present two cases and our review of the literature, we conclude that anatomic repair is superior to conventional repair of CCTGA in terms of protection against dysfunction and failure of the anatomic right ventricle, tricuspid valve, and conduction system. Long-term follow-up is mandatory.

Cardiac Surgical Procedures↗
PubMed2001

Modified arterial switch operation by sharing the common wall between the great arteries.

BACKGROUND: Suprapulmonary stenosis and coronary arterial obstruction still remain as problems after an arterial switch operation (ASO). We used a modified ASO applying the common wall and in situ transfer techniques to improve the current procedure. METHODS: From October 1996 to December 1997, 11 babies aged 6 days to 3 months with transposition of the great arteries underwent a modified ASO which included sharing the common wall between the great arteries until above the anterior neoaortic suture-line for coronary and pulmonary artery reconstruction. Coronary arteries were of usual type in three cases, juxtacommissural origin in five, and a high takeoff in one; all were redirected almost in situ. RESULTS: There was no early death (< 30 d), coronary or bleeding problems. One late death occurred after a repeat surgery for suprapulmonary stenosis. This was caused by upward stretching of the left pulmonary artery, which was placed above the high left-sided neoaortic anastomosis for in situ transfer of the high takeoff coronary arteries. Intraluminal growth of the adventitia also contributed to suprapulmonary stenosis, which decreased significantly when the common wall adventitia was cleaned in the last two cases we operated on. Ten patients were doing well at follow-up (30.9 +/- 5.2 mo). CONCLUSIONS: This modified ASO by common wall and in situ transfer might avoid coronary kinking and lessen the chance of postoperative bleeding. To avoid suprapulmonary stenosis, common wall adventitia inside the pulmonary pathway should be cleaned, and the left and right pulmonary arteries should also be kept in situ as possible as in coronary redirection.

Humans↗
PubMed2001

Valveless outflow reconstruction using autologous tissue as a posterior wall for pulmonary atresia with ventricular septal defect.

BACKGROUND AND PURPOSE: Reoperation is inevitable for some patients with pulmonary atresia who receive a heterograft or homograft in a primary Rastelli operation. Nonetheless, the need for reoperation in patients with classic Fallot's tetralogy who have undergone total correction with a transannular patch is unusual. We sought to change pulmonary atresia into Fallot's tetralogy and used a transannular patch instead of the conventional Rastelli operation. PATIENTS AND METHODS: Valveless outflow direct reconstruction was performed on 10 consecutive patients with pulmonary atresia and ventricular septal defect between August 1997 and 1999. Patient ages ranged from 1.3 to 11.5 years. A Blalock-Taussig shunt was previously constructed in four of these patients and a central shunt was constructed in five. The major aortopulmonary collateral arteries were occluded in one patient by repeated coil embolization after the central shunt. The strategy was to connect the right ventriculotomy with the pulmonary arteries directly, even if there was a gap with a long atretic cord. In patients with a previous central shunt covered with a Gore-Tex membrane, the reactive visceral pericardium over the in situ tissue (the left atrium, right ventricle, or aorta) was used as the autologous posterior wall. Thus, only autologous, fresh pericardium without a valve was used to cover the anterior part of the right ventricular outflow tract, as in the repair of classic Fallot's tetralogy with a transannular patch. RESULTS: There was no mortality, and the postoperative central venous pressure was low in all patients. No gradient was noted across the right ventricular outflow tract. Follow-up echocardiography revealed a competent tricuspid valve with mild pulmonary regurgitation in all patients. CONCLUSIONS: The results of this study suggest that valveless outflow direct reconstruction provides adequate pulmonary circulation without hypertension in pulmonary atresia patients with a ventricular septal defect if the tricuspid valve is competent.

Child, Preschool↗
PubMed2000

Concomitant management of airway and its adjacent vascular pathology in addition to repair of congenital cardiac defects.

Respiratory symptoms are often present in infants with congenital cardiac anomalies, but the intrinsic pathology of the airway itself or external compression by abnormal vessels is frequently undetected before cardiac repair. We collected 12 patients with airway pathology from July 1996 to October 1998; all had definite diagnosis of lesions of the airway and its adjacent vessels by preoperative ultrafast computed tomography. Four had intrinsic pathology (one retrotracheal diverticulum, three tracheal stenosis) as well as external compression. Among them, six had complete vascular ring, four partial rings and three had bronchial compression by aneurysmal dilatation of branch pulmonary arteries. Simultaneous airway repair (one diverticulectomy, three patch tracheoplasty) and external decompression were performed in ten cases under cardiopulmonary bypass, nine of ten had simultaneous cardiac repair; the other two were done before cardiac repair. All survived except three. We concluded that ultrafast computed tomography is indispensable for definite diagnosis of airway and adjacent cardiovascular pathology. Mere repair of congenital cardiac defects without rectification of the airway and its adjacent structures is incompatible with survival.

Aorta↗
PubMed2000

Influence of aortopulmonary rotation on the anomalous coronary artery pattern in tetralogy of fallot.

Three main patterns of aortic sinus rotation were defined on 517 lateral angiograms of tetralogy of Fallot with 14 cases of anomalous coronary artery pattern occurring only in patients with a right anterior or right lateral aorta. The significant dependence of coronary artery types on the aortic sinus pattern made it possible to predict the predisposing coronary artery pattern in tetralogy of Fallot based on the aortic sinus pattern.

Coronary Angiography↗
PubMed2000

Modified arterial switch operation by spiral reconstruction of the great arteries in transposition.

BACKGROUND: Spiral relationship of the normally related great arteries (SRGA) has never been reconstructed in an arterial switch operation. METHODS: From March 1998 to April 1999, 9 consecutive cases of transposition of the great arteries (TGA) family (from 2 days to 1.6 years old) underwent arterial switch operations with SRGA at our hospital. Two had a congenitally corrected TGA (plus atrial redirection). Lecompte maneuver was not used in all. The posterior wall of pulmonary trunk was not divided but three were reattached, two of whom had had previous pulmonary trunk banding. Thus the wall was shared between the great arteries facing each other. RESULTS: All survived the operation. Supraaortic stenosis was balloon-dilated in 2 cases of early series, but technical modifications later were able to avoid it. Angiogram showed smooth flow into SRGA without upward and anterior tilting of the pulmonary bifurcation. All great and coronary arteries were patent. All were doing well on follow-up (16.5 +/- 4.2 months). CONCLUSIONS: We concluded that the techniques to relocate the coronary arteries using common wall and in situ switch could also be applied to pulmonary arterial reconstruction, so that SRGA can be resumed in TGA.

Anastomosis, Surgical↗
PubMed2000

Role of electrophysiological studies and arrhythmia intervention in repairing Ebstein's anomaly.

BACKGROUND: Repairing Ebstein's anomaly without correction of associated arrhythmia may result in sudden death. Catheter or surgical ablation is indicated for various symptomatic tachyarrhythmias in Ebstein's anomaly. METHODS: Between October 1973 and October 1997, 30 patients with Ebstein's anomaly underwent surgical repair in our hospital. Tricuspid valve replacement was performed in 13 patients, tricuspid annuloplasty and valvuloplasty in the remaining 17 patients. Preoperative electrophysiological studies were performed in 11 patients after 1980. Concomitant arrhythmia ablation was done in 10 patients: 4 for Wolff-Parkinson-White syndrome, 2 for atrioventricular (AV) nodal reentrant tachycardia, one for ventricular tachycardia and 3 for paroxysmal atrial flutter and fibrillation. RESULTS: No mortality or major morbidity occurred in those patients undergoing arrhythmia intervention. There were 7 deaths in total; 6 died suddenly, and the other died of purulent mediastinitis. None of the 6 sudden deaths underwent preoperative electrophysiological evaluation. The functional recovery was good in all survivals. CONCLUSIONS: We conclude that detailed preoperative electrophysiological evaluation in patients with Ebstein's anomaly is mandatory. Aggressive surgical intervention of the associated arrhythmias in addition to anatomic correction can reduce the sudden death in Ebstein's anomaly.

Adolescent↗
PubMed2000

First successful ventricular septation of double inlet left ventricle in Taiwan.

Patients with a double inlet ventricle may undergo surgery using a modified Fontan procedure, in which the pulmonary ventricle is not utilized, or a procedure in which a pulmonary ventricle is created through ventricular septation. Ventricular septation is preferred to the Fontan procedure because there is better cardiorespiratory response to exercise after surgery. A 4-year-old girl with Holmes heart underwent ventricular septation on 12 May 1998. Pulmonary artery banding had been performed at 3 months of age and rebanding 16 days later. She was well and continued to grow. Ultrafast computed tomography and cardiac catheterization prior to surgery showed a double inlet left ventricle (LV) connected to a right posterior aorta with a right-sided rudimentary right ventricle that drained to the left anterior pulmonary trunk. Left ventricular end diastolic volume was 218% of normal and the ejection fraction was 79%. After debanding and enlargement of the bulboventricular foramen, a 3 x 4-cm composite patch of equine pericardium and Dacron velour was used to septate the ventricle, with transmural stitching at the apical portion. The patient survived the operation with complete atrioventricular block, and was extubated 6 days later. A permanent pacemaker was implanted 1 month later. One year after surgery, she was doing well. Echocardiography revealed paradoxical septal motion with good ventricular function. This is the first report of successful ventricular septation of a double inlet left ventricle performed in Taiwan.

Cardiac Surgical Procedures↗
PubMed1999

Rescue for acute myocarditis with shock by extracorporeal membrane oxygenation.

BACKGROUND: Acute myocarditis (AM) complicated with refractory cardiogenic shock carries a very high mortality. We report our experience in treating these patients, who were rescued by extracorporeal membrane oxygenation (ECMO) and intravenous immunoglobulin. METHODS: Over a 5-year period, 5 patients with AM were rescued with ECMO in our hospital. Femoral venoarterial ECMO was performed in 4 patients, and right atrium-left atrium-aorta ECMO in the other 1 due to ventricular dysfunction. Hemofiltration was applied to 3 patients. Marked elevated creatine kinase, its MB form, and troponin T (TnT) were found before ECMO. RESULTS: All the patients could be weaned off the ECMO after 140.0+/-57.7 hours of ECMO support. One patient died of multiple organ failure 10 days later after removal of ECMO, resulting in a 20% mortality. Renal function returned to normal in all survivors. The 4 survivors were discharged uneventfully in 23.3+/-8.3 days and resumed functional class I status. The TnT level declined to the low level within 3 days (slope -4.94+/-1.18 ng/mL/day), and might be an indicator of good recovery of myocardium. CONCLUSIONS: ECMO can provide an effective and simple treatment for critical AM with a satisfactory result and reduce the possibility of progressive cardiomyopathy.

Acute Disease↗