Micro-CT analysis of volumetric change of calcium silicate-based root-end filling materials / 대한치과재료학회지

The purpose of this study was to investigate the effect of blood contact and tooth mobility on volumetric changes of calcium silicate-based root-end filling materials using a micro-CT. Three calcium silicate-based materials (ProRoot MTA, Biodentine, and RetroMTA) were used in this study. Seventy-two extracted human single-rooted premolars were obturated with gutta percha. Root-end resection and root-end preparation were performed. After root-end filling with tested materials, the tooth specimens were immersed in saline or blood for 5 days in a 37 ℃ incubator (n=8). The tooth specimens were mounted in a chewing simulator to simulate tooth mobility with a force of 30 N and 20,000 cycles. Micro-CT scans were performed immediately after root-end filling and after exposure to storage media or simulation of tooth mobility. The volume loss (%) was obtained from difference in the percentage of defects of materials between first and second micro-CT scans. Apical volume loss (%; volume loss from resected surface to 1 mm from the surface) was calculated for tooth mobility simulating groups. Biodentine showed larger total volume loss than ProRoot MTA and RetroMTA in saline and blood. ProRoot MTA had smaller total volume loss in blood than in saline. Under the condition simulating tooth mobility, total volume loss was similar among materials, and apical volume loss of Biodentine was larger than that of RetroMTA. In conclusion, ProRoot MTA or Retro MTA is recommended in clinical situation of intentional replantation where tooth mobility or direct contact with blood may occur.

Impact of Pulmonary Arterial Elastance on Right Ventricular Mechanics and Exercise Capacity in Repaired Tetralogy of Fallot

Background and Objectives@#Pathophysiological changes of right ventricle (RV) after repair of tetralogy of Fallot (TOF) are coupled with a highly compliant low-pressure pulmonary artery (PA) system. This study aimed to determine whether pulmonary vascular function was associated with RV parameters and exercise capacity, and its impact on RV remodeling after pulmonary valve replacement. @*Methods@#In a total of 48 patients over 18 years of age with repaired TOF, pulmonary arterial elastance (Ea), RV volume data, and RV-PA coupling ratio were calculated and analyzed in relation to exercise capacity. @*Results@#Patients with a low Ea showed a more severe pulmonary regurgitation volume index, greater RV end-diastolic volume index, and greater effective RV stroke volume (p=0.039, p=0.013, and p=0.011, respectively). Patients with a high Ea had lower exercise capacity than those with a low Ea (peak oxygen consumption [peak VO2 ] rate: 25.8±7.7 vs. 34.3±5.5 mL/kg/min, respectively, p=0.003), while peak VO2 was inversely correlated with Ea and mean PA pressure (p=0.004 and p=0.004, respectively). In the univariate analysis, a higher preoperative RV end-diastolic volume index and RV end-systolic volume index, left ventricular end-systolic volume index, and higher RV-PA coupling ratio were risk factors for suboptimal outcomes. Preoperative RV volume and RV-PA coupling ratio reflecting the adaptive PA system response are important factors in optimal postoperative results. @*Conclusions@#We found that PA vascular dysfunction, presenting as elevated Ea in TOF, may contribute to exercise intolerance. However, Ea was inversely correlated with pulmonary regurgitation (PR) severity, which may prevent PR, RV dilatation, and left ventricular dilatation in the absence of significant pulmonary stenosis.

Historical Review and Future of Cardiac Xenotransplantation

Along with the development of immunosuppressive drugs, major advances on xenotransplantation were achieved by understanding the immunobiology of xenograft rejection. Most importantly, three predominant carbohydrate antigens on porcine endothelial cells were key elements provoking hyperacute rejection: α1,3-galactose, SDa blood group antigen, and N-glycolylneuraminic acid. Preformed antibodies binding to the porcine major xenoantigen causes complement activation and endothelial cell activation, leading to xenograft injury and intravascular thrombosis. Recent advances in genetic engineering enabled knock-outs of these major xenoantigens, thus producing xenografts with less hyperacute rejection rates. Another milestone in the history of xenotransplantation was the development of co-stimulation blockaded strategy. Unlike allotransplantation, xenotransplantation requires blockade of CD40-CD40L pathway to prevent T-cell dependent B-cell activation and antibody production. In 2010s, advanced genetic engineering of xenograft by inducing the expression of multiple human transgenes became available.So-called ‘multi-gene’ xenografts expressing human transgenes such as thrombomodulin and endothelial protein C receptor were introduced, which resulted in the reduction of thrombotic events and improvement of xenograft survival. Still, there are many limitations to clinical translation of cardiac xenotransplantation. Along with technical challenges, zoonotic infection and physiological discordances are major obstacles. Social barriers including healthcare costs also need to be addressed. Although there are several remaining obstacles to overcome, xenotransplantation would surely become the novel option for millions of patients with end-stage heart failure who have limited options to traditional therapeutics.

Long-term Outcome of Fontan-Associated Protein-Losing Enteropathy: Treatment Modality and Predictive Factor of Mortality

Background and Objectives@#Protein-losing enteropathy (PLE) is a devastating complication after the Fontan operation. This study aimed to investigate the clinical characteristics, treatment response, and outcomes of Fontan-associated PLE. @*Methods@#We reviewed the medical records of 38 patients with Fontan-associated PLE from 1992 to 2018 in 2 institutions in Korea. @*Results@#PLE occurred in 4.6% of the total 832 patients after the Fontan operation. After a mean period of 7.7 years after Fontan operation, PLE was diagnosed at a mean age of 11.6years. The mean follow-up period was 8.9 years. The survival rates were 81.6% at 5 years and 76.5% at 10 years. In the multivariate analysis, New York Heart Association Functional classification III or IV (p=0.002), low aortic oxygen saturation (<90%) (p=0.003), and ventricular dysfunction (p=0.032) at the time of PLE diagnosis were found as predictors of mortality. PLE was resolved in 10 of the 38 patients after treatment. Among medical managements, an initial heparin response was associated with survival (p=0.043). Heparin treatment resulted in resolution in 4 patients. We found no evidence on pulmonary vasodilator therapy alone. PLE was also resolved after surgical Fontan fenestration (2/6), aortopulmonary collateral ligation (1/1), and transplantation (1/1). @*Conclusions@#The survival rate of patients with Fontan-associated PLE has improved with the advancement of conservative care. Although there is no definitive method, some treatments led to the resolution of PLE in one-fourth of the patients. Further investigations are needed to develop the best prevention and therapeutic strategies for PLE.

Real-time analysis of temperature change in composite photopolymerization using non-contact infrared sensor / 대한치과재료학회지

The aim of this study was to investigate the effects of the radiant emittance of an LED light on temperature change during composite photopolymerization using a non-contact infrared sensor. A thermometer was prepared using a non-contact infrared sensor and a microcontroller. After preparing a disc-shaped composite specimen using a micro-hybrid conventional (Z250) or nano bulk-fill (BFP) composite, the temperature change of the prepared composite during photopolymerization was measured based on three photopolymerization protocols (Duty ratio/exposure time; 100%/20 s, 50%/40 s, and Increase (0→100%)/40 s) using a pulse width modulated (PWM) LED light. Subsequently, second light exposure, having the same protocol as the first, was performed on the photopolymerized composite. The first peak temperature rise of composite photopolymerization (ΔT total) and second peak temperature rise caused by the LED light (ΔT light ) were obtained from the temperature change vs. time curve.The net peak temperature rise caused by the curing heat of the composite (ΔT composite ) was obtained by subtracting the second curve from the first one. The peak time was defined as the time when ΔT composite occurred. ΔT total and ΔT composite of the 100%/20 s group were the highest and ΔT light of the 50%/40 s group was the lowest for both the composites (p<0.05). The temperature rise of Z250 was higher than that of BFP in all the groups except the ΔT composite of the Increase/40 s group (p<0.05). The peak time of the Increase/40 s group was the longest in both the composites, and the peak time of BFP was longer than that of Z250 in all the photopolymerization protocols (p<0.05). A real-time analysis of the temperature change during composite photopolymerization was effectively performed using the non-contact infrared sensor. Through this analysis, the polymerization kinetics of the composite could also be evaluated.

Real time measurement of the transmittance change of composite during light curing / 대한치과재료학회지

The purpose of this study was to measure the transmittance change of composites during light curing in real time according to different shades and thicknesses. An instrument using pulse width modulation-curing light was developed to measure the transmittance of composites in real time. A micro-hybrid composite, Filtek Z250, was used for %transmittance measurement with five different shades (A1, A2, A3, A3.5, A4) and 4 different thicknesses (0.16, 0.5, 1.0, 1.5 mm). The maximum value of d(%Transmittance)/dt and peak time were used to observe polymerization kinetics. Attenuation coefficient was also compared between pre and post cured specimens. The transmittance increased in all specimens after polymerization. A2 showed the highest and A1 showed the lowest transmittance in both pre and post curing. The transmittance change and maximum rate of change were highest in A2 and lowest in A3.5, and the peak time, which ranged in 3.10 to 4.07, was not significantly different among shades. As the specimen became thinner, both the transmittance and rate of change increased, and the peak time was maximum at 1.5 mm thickness. The absolute value of attenuation coefficient decreased after polymerization in all specimens. In conclusion, the transmittance of composite increased after polymerization. Each shade showed different transmittance value for both pre and post curing state, and thinner specimen showed higher transmittance value. Polymerization kinetics could also be observed through the rate of transmittance change over time.

Real time measurement of the transmittance change of composite during light curing / 대한치과재료학회지

The purpose of this study was to measure the transmittance change of composites during light curing in real time according to different shades and thicknesses. An instrument using pulse width modulation-curing light was developed to measure the transmittance of composites in real time. A micro-hybrid composite, Filtek Z250, was used for %transmittance measurement with five different shades (A1, A2, A3, A3.5, A4) and 4 different thicknesses (0.16, 0.5, 1.0, 1.5 mm). The maximum value of d(%Transmittance)/dt and peak time were used to observe polymerization kinetics. Attenuation coefficient was also compared between pre and post cured specimens. The transmittance increased in all specimens after polymerization. A2 showed the highest and A1 showed the lowest transmittance in both pre and post curing. The transmittance change and maximum rate of change were highest in A2 and lowest in A3.5, and the peak time, which ranged in 3.10 to 4.07, was not significantly different among shades. As the specimen became thinner, both the transmittance and rate of change increased, and the peak time was maximum at 1.5 mm thickness. The absolute value of attenuation coefficient decreased after polymerization in all specimens. In conclusion, the transmittance of composite increased after polymerization. Each shade showed different transmittance value for both pre and post curing state, and thinner specimen showed higher transmittance value. Polymerization kinetics could also be observed through the rate of transmittance change over time.

Cone Repair in Adult Patients with Ebstein Anomaly

Ebstein anomaly is a rare congenital heart malformation typically involving the tricuspid valve and the right ventricle that has a wide range of anatomical and pathophysiological presentations. Various surgical repair techniques for Ebstein anomaly have been reported because of its near-infinite anatomical variability. Cone repair for Ebstein anomaly can achieve nearly anatomical reconstruction of the tricuspid valve with promising outcomes.In this article, the surgical techniques for cone repair in adult patients with Ebstein anomaly are described in detail, and clinical experiences and technically challenging cases are presented.

Biventricular Hypertrophic Cardiomyopathy with Severe Right Ventricular Outflow Track Obstruction / 대한내과학회지

Hypertrophic cardiomyopathy (HCM) has diverse pathophysiological and clinical features, according to the extent and severity of the hypertrophy development. Hypertrophy mostly involves the left ventricle and sometimes causes a left ventricular outflow tract obstruction. Right ventricular involvement is less frequent, and even the severe form of a right ventricular outflow tract (RVOT) obstruction by concurrent right ventricular hypertrophy in a patient with HCM is rare. We report a case of biventricular HCM with a clinically, morphologically, and hemodynamically significant RVOT obstruction, which had been treated successfully with surgical myectomy.

Biventricular Hypertrophic Cardiomyopathy with Severe Right Ventricular Outflow Track Obstruction / 대한내과학회지

Hypertrophic cardiomyopathy (HCM) has diverse pathophysiological and clinical features, according to the extent and severity of the hypertrophy development. Hypertrophy mostly involves the left ventricle and sometimes causes a left ventricular outflow tract obstruction. Right ventricular involvement is less frequent, and even the severe form of a right ventricular outflow tract (RVOT) obstruction by concurrent right ventricular hypertrophy in a patient with HCM is rare. We report a case of biventricular HCM with a clinically, morphologically, and hemodynamically significant RVOT obstruction, which had been treated successfully with surgical myectomy.

Effect of apical constriction diameter, irrigant flow rate, and needle tip design on apical pressure / 대한치과재료학회지

The purpose of this study was to evaluate the effects of apical constriction (AC) diameter, irrigant flow rate, and needle tip design on apical pressure (AP) during the root canal irrigation. Five extracted human mandibular premolars were instrumented up to #35 (0.06 taper) using nickel-titanium rotary instruments. AC was determined at 1 mm from the apical foramen. Three needles with different tip designs (notched, side-vented, and flat) were placed 3 mm from AC. APs were measured with varying flow rates of 0.05, 0.1, 0.2, and 0.3 mL/s. The AC diameter of the teeth was enlarged to #40 and #45 (0.06 taper) successively, and the aforementioned measurement procedure was repeated (n=5). When the other conditions were controlled, AP increased with decreasing AC diameter or increasing irrigant flow rate, and the AP of flat needle was the highest, followed by notched, and side-vented needle (p0.35 mm, open-end (notched or flat) needles can be used to improve irrigant replacement in the apical portion using a flow rate of 0.05 mL/s.

Effect of needle tip design and position, and irrigant flow rate on apical pressure / 대한치과재료학회지

The purpose of this study was to evaluate the effect of needle tip design and position, and irrigant flow rate on apical pressure (AP) during root canal irrigation. Five human mandibular premolars were instrumented up to #35 (0.06 taper) using nickel-titanium rotary instruments. Three different needles according to change of needle tip design (notched, side-vented, and flat) were positioned at the point of 1, 3, and 5 mm from the apical constriction (needle tip position). For each needle tip design and position, APs were measured with varying flow rates of 0.05, 0.1, 0.2, and 0.3 ml/s. When the other conditions were controlled, AP increased with decreasing needle tip position or increasing irrigant flow rate (p < 0.05). The AP of flat needle was the highest, followed by notched, side-vented needle for the same needle tip position and irrigant flow rate. The APs at needle tip position of 1 mm or with more than 0.1 ml/s flow rate were higher than central venous pressure (5.88 mmHg) for all conditions. Flat needle was not recommended for clinical use due to sharp increase of AP with changing needle tip position and irrigant flow rate. For safe and effective root canal irrigation, irrigant should be applied with the needle tip position of 3 mm and flow rate of less than 0.05 ml/s.

Anatomic Repair Including Hemi-Mustard in Congenitally Corrected Transposition of the Great Arteries: What We know and Still Need to Know

No abstract available.

Hemodynamic Follow-Up in Adult Patients with Pulmonary Hypertension Associated with Atrial Septal Defect after Partial Closure

PURPOSE: We evaluated the hemodynamic statuses of patients after partial closure of atrial septal defects with fenestration due to pulmonary hypertension. MATERIALS AND METHODS: Seventeen adult patients underwent partial atrial septal defect closure and follow-up cardiac catheterization. We analyzed hemodynamic data and clinical parameters before and after closure. RESULTS: The median age at closure was 29 years old. The baseline Qp/Qs was 1.9+/-0.6. The median interval from the operation to the cardiac catheterization was 27 months. The CT ratio decreased from 0.55+/-0.07 to 0.48+/-0.06 (p<0.05). The mean pulmonary arterial pressure decreased from 50.0+/-11.5 mm Hg to 32.5+/-14.4 mm Hg (p<0.05), and the pulmonary resistance index decreased from 9.2+/-3.6 Wood units*m2 to 6.3+/-3.8 Wood units*m2 (p<0.05). Eleven patients (64.7%) continued to exhibit high pulmonary resistance (over 3.0 Wood units*m2) after closure. These patients had significantly higher pulmonary resistance indices and mean pulmonary arterial pressures based on oxygen testing before the partial closures (p<0.05). However, no significant predictors of post-closure pulmonary hypertension were identified. CONCLUSION: Despite improvement in symptoms and hemodynamics after partial closure of an atrial septal defect, pulmonary hypertension should be monitored carefully.

Impact of postoperative duration of Aspirin use on longevity of bioprosthetic pulmonary valve in patients who underwent congenital heart disease repair / 소아과

PURPOSE: Generally, aspirin is used as a protective agent against thrombogenic phenomenon after pulmonary valve replacement (PVR) using a bioprosthetic valve. However, the appropriate duration of aspirin use is unclear. We analyzed the impact of postoperative duration of aspirin use on the longevity of bioprosthetic pulmonary valves in patients who underwent repair for congenital heart diseases. METHODS: We retrospectively reviewed the clinical data of 137 patients who underwent PVR using a bioprosthetic valve between January 2000 and December 2003. Among these patients, 89 were included in our study and divided into groups I (≤12 months) and II (>12 months) according to duration of aspirin use. We analyzed echocardiographic data from 9 to 11 years after PVR. Pulmonary vale stenosis and regurgitation were classified as mild, moderate, or severe. RESULTS: The 89 patients consisted of 53 males and 36 females. Their mean age was 14.3±8.9 years (range, 2.6–48 years) and body weight was 37.6±14.7 kg (range, 14–72 kg). The postoperative duration of aspirin use was 7.3±2.9 months in group I and 32.8±28.4 months in group II. However, no significant difference in sex ratio, age, body weight, type of bioprosthetic valve, and number of early redo-PVRs. In the comparison of echocardiographic data about 10 years later, no significant difference in pulmonary valve function was found. The overall freedom rate from redo-PVR at 10 years showed no significant difference (P=0.498). CONCLUSION: Our results indicated no benefit from long-term aspirin medication (>6 months) in patients who underwent PVR with a bioprosthetic valve.

Stepwise Approach Using Combined Management in Patients with Congenital Heart Disease and Borderline Pulmonary Vascular Disease

BACKGROUND AND OBJECTIVES: Despite remarkable advances in pediatric cardiology, pulmonary arterial hypertension associated with congenital heart disease remains a major problem. In the past decade new vasodilators have been introduced and appear to be effective in reducing pulmonary vascular resistance (PVR). SUBJECTS AND METHODS: From 2000 to 2011, we retrospectively reviewed the records of 22 patients who had congenital septal defects and borderline pulmonary vascular disease (PVD). The PVR in these patients was from 6 to 16 wood units . m2, and/or the systolic pulmonary arterial pressure was more than 2/3 of the systemic arterial pressure. RESULTS: The median age was 16 years (range, 9 months-46 years). The median duration of follow-up was 7.4 years (range, 1.4-11.7 years). According to hemodynamic data and clinical symptoms, the initial management comprised targeted medical therapy in four (18%), complete closure in four (18%), and partial closure in 14 patients (63.6%). In the four patients who had a high PVR and negative vasoreactivity, the PVR decreased and vasoreactivity increased after targeted medical therapy; three of these patients underwent cardiac surgery later. Finally, 11 (50%) received targeted medical therapy and 21 patients (95.4%) underwent cardiac surgery. Complete closure resulted in six patients and partial closure in 17 patients. Mortality was observed in two patients. The other 19 patients (91%) had New York Heart Association functional class I. CONCLUSION: Targeted medical therapy may be effective in reducing PVR in patients with congenital heart disease and borderline PVD. A stepwise approach may help to achieve improved outcomes in these patients.

Primary repair of symptomatic neonates with tetralogy of Fallot with or without pulmonary atresia / 소아과

Recently, surgical outcomes of repair of tetralogy of Fallot (TOF) have improved. For patients with TOF older than 3 months, primary repair has been advocated regardless of symptoms. However, a surgical approach to symptomatic TOF in neonates or very young infants remains elusive. Traditionally, there have been two surgical options for these patients: primary repair versus an initial aortopulmonary shunt followed by repair. Early primary repair provides several advantages, including avoidance of shunt-related complications, early relief of hypoxia, promotion of normal lung development, avoidance of ventricular hypertrophy and fibrosis, and psychological comfort to the family. Because of advances in cardiopulmonary bypass techniques and accumulated experience in neonatal cardiac surgery, primary repair in neonates with TOF has been performed with excellent early outcomes (early mortality<5%), which may be superior to the outcomes of aortopulmonary shunting. A remaining question regarding surgical options is whether shunts can preserve the pulmonary valve annulus for TOF neonates with pulmonary stenosis. Symptomatic neonates and older infants have different anatomies of right ventricular outflow tract (RVOT) obstructions, which in neonates are nearly always caused by a hypoplastic pulmonary valve annulus instead of infundibular obstruction. Therefore, a shunt is less likely to preserve the pulmonary valve annulus than is primary repair. Primary repair of TOF can be performed safely in most symptomatic neonates. Patients who have had primary repair should be closely followed up to evaluate the RVOT pathology and right ventricular function.

Surgical Management of Left Ventricular Outflow Tract Obstruction after Biventricular Repair of Double Outlet Right Ventricle

Regardless of the preoperative morphology and the type of operation, left ventricular outflow tract obstruction (LVOTO) after biventricular repair of double outlet right ventricle (DORV) may develop. This report presents our 10-yr experience with surgical management of LVOTO after biventricular repair of DORV. Between 1996 and 2006, 15 patients underwent reoperation for subaortic stenosis after biventricular repair of DORV. The mean age at biventricular repair was 23.3+/-18.3 months (1.1-64.2). Biventricular repairs included tunnel constructions from the left ventricle to the aorta in 14 cases and an arterial switch operation in one. The mean left ventricle-to-aorta peak pressure gradient was 54.0+/-37.7 mmHg (15-140) after a mean follow-up of 9.5+/-6.3 yr. We performed extended septoplasty in nine patients and fibromuscular resection in six. There were no early or late mortality. There was one heart block and one aortic valve injury after an extended septoplasty, and two and one after a fibromuscular resection. No patient required reoperation for recurrent subaortic stenosis. The mean pressure gradient was 11.2+/-11.4 mmHg (0-34) after a mean follow-up of 5.6+/-2.7 yr. Extended septoplasty is a safe and effective method for the treatment of subaortic stenosis, especially in cases with a long-tunnel shaped LVOTO.

The Application of a Bi-ventricular Assist Device for a Low Weight (2.4 kg) Neonate with Coarctation of the Aorta and Critical Aortic Stenosis / 대한흉부외과학회지

A 5-day-old neonate (body weight=2.4 kg) with coarctation of the aorta and critical aortic stenosis underwent an interventional balloon valvuloplasty for aortic stenosis. During the intervention, cardiac arrest occurred due to injury of the right carotid artery by the guide wire. An extracorporeal membrane oxygenator (ECMO) was applied. After 1 day's support, total surgical correction was achieved; however, in the immediate postoperative period, cardiac function was severely depressed. We applied a bi-ventricular assist device (bi-VAD) instead of an ECMO and we were able to wean the patient off the bi-VAD device after 3 days' support. The patient was discharged without severe complications.

The Recent Surgical Result of Total Anomalous Pulmonary Venous Return

BACKGROUND AND OBJECTIVES: Recent surgical results from total anomalous pulmonary venous return (TAPVR) are reported to have improved; however, mortality and morbidity are still high in the univentricles. This review was performed in order to demonstrate surgical results from TAPVR for recent years in a single institute. SUBJECTS AND METHODS: A total of 53 patients with TAPVR underwent surgery between January 2000 and December 2008. Preoperative anatomy and hemodynamics were evaluated by 2-dimensional echocardiogram. We reviewed medical records on preoperative management, age, and body weight at time of surgery, postoperative mortality, and pulmonary venous obstruction. RESULTS: The study included 36 biventricle patients and 17 univentricle patients. Median age and weight at time of surgery were 26 days and 3.5 kg, respectively. During the mean follow up period of 48.2 months, a total of 11 deaths and 8 early deaths occurred. Postoperative pulmonary venous stenosis occurred in 8 patients. Among 36 biventricle patients, mortality occurred in 1 patient and postoperative pulmonary venous stenosis occurred in 6 patients. No statistical significances were observed between postoperative pulmonary venous stenosis and other factors. Among 17 univentricule patients, mortality was 10, including 7 early deaths, and postoperative pulmonary venous stenosis occurred in 2 patients. Combined palliations were modified Blalock-Taussig (BT) shunts in 7, pulmonary artery banding (PAB) in 3, bidirectional cavopulmonary shunt in 5, and the Fontan procedure in 1. The highest mortality was recorded in patients with a modified BT shunt (85.7%) and next in patients with PAB (66.6%). Mortality was not related to anatomy of TAPVR, nor preoperative obstruction, but with significant age and weight at time of surgery. CONCLUSION: Despite improvement in operative results from TAPVR, surgery in univentricles is highly risky, especially with low weight and early age, with concomitant palliation.