Changes in health-related quality of life and working competence before and after heart transplantation: one-year follow-up in Taiwan.
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Adolescent↗
Biomedical subjects
N K Chou
Publications and source records attributed to N K Chou.
Hepatic encephalopathy and cerebral blood flow improved by liver dialysis treatment.
Eight acute liver failure patients, all in grade IV hepatic encephalopathy, were administered liver dialysis treatment with the Hemo Therapies Unit (Hemo Therapies Inc, San Diego, CA, USA). The patients were evaluated to determine whether the Glasgow Coma Scale score and cerebral blood flow improved with treatment. After the initial treatment, consciousness levels as measured by the Glasgow Coma Scale improved from a pre-treatment median of 5 (range 3 to 6) to a post-treatment median of 7 (range 5 to 9) (p=0.0005 by paired Wilcoxon test); mean blood flow velocity in the middle cerebral arteries as shown by transcranial Doppler sonography increased from a median of 37.85 cm/sec (range 20.3 to 114.0) to 57.90 (32.5 to 135.0) post-treatment (p=0.022); however, there was no significant change in the pulsatility index from a median of 1.18 (range 0.61 to 1.71) to 0.85 (range 0.70 to approximately 1.79) post-treatment (p=0.13). The 8 patients received 2 to 7 (median 5.5) times of daily 6-h liver dialysis treatments. Following the completion of all liver dialysis treatments, hepatic coma was fully resolved in 4 of 8 patients (50%) Three of 8 patients (37.5%) survived to hospital discharge, whereas 5 patients did not survive due to irreversible liver function and associated complications. In conclusion, liver dialysis treatment could improve hepatic encephalopathy, but the prognosis still depended on the underlying diseases.
Adult↗
How to promote organ donation: a successful experience at the National Taiwan University Hospital.
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Health Education↗
Preliminary result of an algorithm to select proper ventricular assist devices for high-risk patients with extracorporeal membrane oxygenation support.
BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is not suitable for long-term support because of its high incidence of complications. Conversion from ECMO to ventricular assist device (VAD) is reasonable, and we have developed a simple algorithm for selecting proper VADs for these ECMO-supported patients. METHODS: We converted 12 patients who were receiving ECMO support to VAD for bridge to transplantation. Group I (n = 6) was converted directly from ECMO to VAD. Group II (n = 6) underwent stage conversion. We added left atrial drainage to ECMO because of lung edema or marked left heart distension. We discontinued drainage after recovery of right heart function. Group II had more unfavorable risk factors for VAD before ECMO. RESULTS: Three patients (50%) in Group I received biventricular VADs. The other 3 patients were converted to left ventricular assist device (LVAD), but only 1 (16.7%) experienced successful conversion. We successfully converted 5 patients (83.3%) in Group II to LVAD without right VAD, and 4 of them could be weaned from the ventilator. The multiple-organ dysfunction score gradually improved in Group II despite additional surgery. Two patients in each group received heart transplantation and survived long term. CONCLUSION: Using a conversion protocol provides a good guideline for making decisions. According to the protocol, right heart and pulmonary function can be clearly assured before shifting to LVAD in these critical ECMO-supported patients.
Algorithms↗
Hepatitis B virus infection in heart transplant recipients in a hepatitis B endemic area.
BACKGROUND: Hepatitis B virus (HBV) infection is hyperendemic in Taiwan. It is almost impossible for us to reject organ donors or recipients with positive serum hepatitis B surface antigen (HBsAg). We report our experience with HBV infection in heart transplant recipients with particular attention to outcome of recipients who were HBsAg+ or who had received donor hearts from HBsAg+ donors. METHODS: We performed a retrospective review of medical records. RESULTS: In the study, we included 101 heart recipients with post-transplant survival of more than 6 months. According to pre-transplant HBV serology markers, we divided patients into 4 groups. Group 1 (n = 8) had been HBsAg+ at the time of heart transplantation. Of these, 6 patients had HBV reactivation in the post-transplant follow-up and needed lamivudine treatment. Complete response was achieved in all 6 patients; however, HBV recurrence occurred in 1 patient after 8 months of lamivudine treatment. The recurrence remained under partial control. Group 2 (n = 16) was HBV naïve at the time of heart transplantation. Of these, 2 received HBsAg+ donor hearts under perioperative hepatitis B immunoglobulin prophylaxis. HBV infection was successfully prevented in 1 patient, but the other contracted HBV hepatitis, which was successfully treated with lamivudine. In Group 2, 10 patients received donor hearts from anti-HBs+ donors, and none contracted HBV hepatitis after transplantation. Group 3 (n = 55) had protective anti-HBs antibody at the time of heart transplantation either from previous HBV vaccination (n = 10) or from natural HGB infection (n = 45). HBsAg+ donor hearts were transplanted into 2 patients with anti-HBs from previous HBV vaccination, and into 8 patients with anti-HBs form natural HBV infection. However, none of these 10 patients who received HBsAg+ donor hearts had HBV hepatitis after transplantation. Group 4 (n = 22) was HBs-, anti-HBs-, and anti-HBc+ at the time of heart transplantation. Of these, 7 patients received HBsAg+ donor hearts. Six patients experienced no HBV hepatitis after heart transplantation, and serum HBV DNA by polymerase chain reaction (PCR) at the time of heart transplantation was negative in all 6 patients. One patient had HBV hepatitis after transplantation, and serum HBV DNA by PCR at the time of heart transplantation also was positive. CONCLUSION: HBV reactivation after the heart transplantation was common but usually well controlled with lamivudine treatment. Therefore, HBV carrier status should not contraindicate heart transplantation. HBsAg+ donor hearts were safely transplanted into anti-HBs+ recipients; therefore, HBsAg+ itself was not a contraindication to heart donation. Patients with HBsAg-, anti-HBs-, anti-HBc+, and negative HBV DNA in the serum by PCR could be protected from HBV infection from HBsAg+ donor hearts. However, patients with HBsAg-, anti-HBs-, anti-HBc+, and positive HBV DNA in the serum by PCR should be recognized as HBV carriers and closely followed for potential HBV flare-up after heart transplantation.
Adolescent↗
Comparisons of cutaneous blood flow reactivity to norepinephrine and sodium nitroprusside between patients with heart transplantation and healthy subjects.
Heart transplant patients are reported to have impaired regulation of the microvasculature. The purpose of this study was to investigate the cutaneous blood flow and its reactivity to sodium nitroprusside (vasodilator, Nipride 0.1%) and norepinephrine (vasoconstrictor, Levophed 0.1%) in patients after heart transplantation in comparison to normal healthy individuals. Eighteen patients after heart transplantation and 16 healthy, nonsmoking individuals served as subjects of the study. Sodium nitroprusside and norepinephrine were introduced by iontophoresis to the skin of the right and left forearms, respectively. After measuring cutaneous blood flow reactivity in the pre-exercise state by laser Doppler flowmetry, subjects were then asked to close and open their fists for 2 min. The same measurements were repeated after exercise. Comparisons between the groups were carried out by the Wilcoxan signed rank test. The Mann Whitney U-test was used for comparison between pre-exercise and post-exercise states. The results demonstrated that sodium nitroprusside significantly increased forearm cutaneous perfusion at rest but produced only a mild increase after exercise. This reactivity was significantly lower after exercise with no significant differences between groups. Norepinephrine decreased cutaneous blood flow at rest. The transplant patients were significantly less sensitive to norepinephrine before but not after exercise. The changes in norepinephrine reactivity with exercise were significantly different between groups (p < 0.05).
Exercise↗
Lamivudine treatment for hepatitis B reactivation in HBsAg carriers after organ transplantation: a 4-year experience.
BACKGROUND: Reactivation of hepatitis B after organ transplantation in hepatitis B surface antigen (HBsAg) carriers may be fatal. In this study, we reported our experience of lamivudine treatment in HBsAg carriers who had post-transplant reactivation of hepatitis B. METHODS: The patients were 15 men and one woman. Nine received kidney transplants, six received heart transplants, and one received a lung transplant. They developed a reactivation of hepatitis B 1-101 months (median, 14 months) after transplantation. They received lamivudine 100 mg daily on a compassionate-use basis, and had regular follow ups. The median pretreatment total serum bilirubin level was 3.0 mg/dL, and the alanine aminotransferase level was 357 U/L. Four of the 16 patients were positive for HBeAg. The serum hepatitis B virus (HBV) DNA levels were > 3000 pg/mL in 13 (81%) patients. Three were coinfected with hepatitis C virus. RESULTS: The overall survival rate was 75%. All four fatal cases had a pretreatment total serum bilirubin level of > or = 3 mg/dL. Serum HBV-DNA soon became undetectable in 12 survivors. Of the 12 survivors, after a median treatment period of 101 weeks, a lamivudine-resistant strain with variation in the YMDD motif of the HBV polymerase gene developed in three (25%). None had significant adverse reactions to lamivudine treatment. CONCLUSIONS: These results indicated that lamivudine is effective in the treatment of post-transplant hepatitis B reactivation, including patients with dual chronic hepatitis B and C. Early recognition of HBV reactivation and prompt lamivudine treatment are important to prevent mortality.
Adult↗
Mechanical bridge with extracorporeal membrane oxygenation and ventricular assist device to heart transplantation.
The aim of this study was to evaluate the effect of double bridges with extracorporeal membrane oxygenation (ECMO) and ventricular assist devices (VADs) in clinical heart transplantation. Between May 1994 and October 2000, 134 patients underwent heart transplantation at the National Taiwan University Hospital. Ten patients received ECMO or VAD support as bridges to transplantation. The ages ranged from 3 to 63 years. The indications included cardiac arrest under cardiopulmonary resuscitation in 2 and profound cardiogenic shock refractory to conventional therapy in 8 patients. Usually ECMO was first set up as rescue therapy. If ECMO could not be weaned off after short-term (usually 1 week) support, suitable VADs (HeartMate or Thoratec VAD) were implanted for medium-term or long-term support. Five patients received ECMO support as emergency rescue for 2 to 9 days, and then moved to Thoratec VAD for 8, 49, and 55 days, respectively, or centrifugal VAD for 31 days, or HeartMate VAD for 224 days. They all survived. The survival rate of double bridges with ECMO and VAD was 100%. In postcardiotomy cardiogenic shock, circulatory collapse from acute myocardial infarction or myocarditis, ECMO is the device of choice for short-term support. If heart transplantation is indicated, VADs should replace ECMO for their superiority as a bridge to heart transplantation. Our preliminary data of double bridges with ECMO and VAD revealed good results and were reliable and effective bridges to transplantation.
Adult↗
Development of a totally implantable pulsatile centrifugal pump as a ventricular assist device.
The Taita No. 1 ventricular assist device (T-VAD) is a totally implantable pulsatile impeller centrifugal pump driven by a magnetically suspended motor. The flow can achieve 2.01 +/- 0.17 L/min against a pressure of 100 mm Hg under 0.266 +/- 0.017 amp and 13.55 +/- 0.41 voltage. The speed was around 3,500 rpm. It consumed less than 6 W of power, resulting in less heat production and mechanical bearing complications. The impeller vane was designed to have both radial and axial curves according to the stream surface and stream lines to reduce thrombosis and hemolysis. Eight calves weighing 80 to 100 kg (mean 87 +/- 12 kg) were used for experiments. With the calves under general anesthesia, left posterolateral thoracotomy was performed to connect the inflow tube with the atrial appendage and to anastomose the outflow tube with the descending aorta. The calves usually awoke and stood up within hours after discontinuation of anesthetics. The mean survival of the calves was 75 +/- 42 days (range 33-148 days). The terminations of experiments were mainly due to infection. During the course of pumping, no significant deterioration of liver or renal function was noted. The evaluation of serum samples from the implanted calves indicated that hemolysis was not associated with use of the T-VAD. The average daily free hemoglobin level was 8.08 +/- 3.05 mg/dl, which was less than the set limit of 20 mg/dl. The red blood cell and platelet count and hemoglobin of implanted animals were within the normal range. In our results, the T-VAD provided competent pulsatile function without severe blood damage or organ dysfunction.
Animals↗
Physiologic analysis of cardiac cycle in an implantable impeller centrifugal left ventricular assist device.
The purpose of this study was to determine the physiologic relationship between the cardiac cycle and the nonpulsatile impeller centrifugal Taita No.1 left ventricular assist device (T-LVAD) in a chronic animal study. The relationship of the cardiac cycle, pump flow, aortic pressure, left ventricle pressure, and pump power were analyzed by 5 phases in 4 stages. The isovolumetric ventricular phase is from mitral valve closure (MVC) to aortic valve opening (AVO) and is called Stage 1. The ejection phase is from AVO to aortic valve closure (AVC) and is called Stage 2. The isovolumetric relaxation phase is from AVC to MVC and is called Stage 3. The passive filling and atrial contraction phase is from MVC to mitral valve opening (MVO) and called Stage 4. Based on evidence from the physiologic volume change of the left ventricle, the change of pump flow of the T-LVAD in a cardiac cycle by variable voltages of pump control was evaluated using animal models. After left posteriolateral thoracotomy via the fifth intercostal space under general anesthesia, the nonpulsatile centrifugal T-LVAD was implanted into 2 healthy calves. The inflow of the T-LVAD was inserted into the left ventricle through the mitral valve via the left atrial appendage. The arterial blood pressure waveform was measured and recorded on the outflow of the T-LVAD. The 4 phases of a cardiac cycle were defined as MVC-AVO (Stage 1), AVO-AVC (Stage 2), AVC-MVO (Stage 3) and MVC-MVO (Stage 4) according to the outflow pressure of the outflow of the T-LVAD and differential pressure between the outflow and inflow of the T-LVAD. We carried out the real-time waveform measurement for electrocardiogram, the outflow pressure, the T-LVAD flow and the speed, as well as open loop and constant voltage (V). In a cardiac cycle, the sensing current of the T-LVAD was inverse to the speed. The flow of the T-LVAD at the 4 stages was measured individually and analyzed with different control voltages from 10 to 18 V. The highest flow ratio of MVC-AVC/AVC-MVC was noted when the T-LVAD worked on 14 V. By using analysis methodology of the flow ratio of a cardiac cycle, the optimal physiologically effective control of the T-LVAD might be achieved.
Animals↗
Growth of endothelial cells on different concentrations of Gly-Arg-Gly-Asp photochemically grafted in polyethylene glycol modified polyurethane.
To improve endothelial cell adhesion and growth on the surface of polyethylene glycol modified polyurethane (PU-PEG), cell adhesive peptide Gly-Arg-Gly-Asp (GRGD) was photochemically grafted to the surface. The surface grafted GRGD-N-Succinimidyl-6-[4'-azido-2'-nitrophenylamino]hexanoate (SANPAH) on a PU-PEG surface was performed by adsorption and subsequent ultraviolet irradiation. Fourier transform infrared spectra (FTIR) and electron spectroscopy for chemical analysis (ESCA) confirmed the GRGD grafted to form a PU-PEG-GRGD surface. The composition fraction of nitrogen calculated from ESCA analysis for the PU-PEG-GRGD surface was well correlated with the concentration of GRGD to be immobilized. Human umbilical vein endothelial cells (ECs) were well adhered and growing on the PU-PEG-GRGD surface. Moreover, the viability of ECs growing on PU-PEG-GRGD surfaces, analyzed by MTT test, was also well correlated with the GRGD concentrations immobilized on the surface. With photochemical techniques, we could manipulate different contents of GRGD to form multiple regions of PU-PEG-GRGD surface that could enhance the growth of ECs on the surface, and the enhancement efficiency was well correlated with GRGD contents.
Cell Adhesion↗
Application of extracorporeal membrane oxygenation in adult burn patients.
Adult respiratory distress syndrome (ARDS) has been the major cause of mortality in burn injury. The authors reported the experience of using extracorporeal membrane oxygenation (ECMO) to treat adult burn patient with ARDS. Three patients with burn or electric injury, around 48.9% of body surface area over second-degree burns, developed ARDS after resuscitation. All had positive blood culture and depended on a ventilator more than 5 days before ECMO. Venovenous (VV) ECMO was started at the beginning of severe respiratory failure with an oxygen index of 61.6 +/- 15.5 cm H2O/mm Hg (> or =40 cm H2O/mm Hg), partial arterial oxygen tension to inspired oxygen fraction (Pa(O2)/Fi(O2)) of 46.1 +/- 7.0 mm Hg (< or =200 mm Hg), positive end expiratory pressure (PEEP) of 15.7 +/- 1.6 cm H2O (> or =10 cm H2O), alveolar-arterial difference in oxygen concentration (A-a D(O2)) of 618.9 +/- 19.3 mm Hg (> or =300 mm Hg), and lung compliance of 17.3 +/- 4.6 ml/cm H2O (< or =30 ml/cm H2O). The VV type had to be converted to the newly designed veno-venoarterial (V-VA) ECMO due to the myocardial dysfunction. Two of three patients survived. The duration of ECMO was 160.2 +/- 51.1 h. Two patients received debridement of escar during ECMO support and desmopressin infusion, and no increased bleeding or coagulopathy was found. The respiratory parameters were significantly improved after ECMO, especially in the survivors. ECMO is also suitable for ARDS in adult burn injury.
Adult↗
Inhomogeneity of myocardial perfusion in heart transplant recipients: evaluation with dobutamine thallium-201 SPECT.
Progressive heterogeneity of thallium-201 single photon emission computed tomography (Tl-201 SPECT) in heart transplant recipients has been documented in Caucasians. However, in Chinese heart transplant recipients, a lower incidence of transplant coronary artery disease (CAD) has been noted than in Western transplant recipients. In this study, we examine whether heterogeneity of Tl-201 SPECT exists in Chinese transplant recipients. Dobutamine Tl-201 SPECT was performed in 40 heart transplant recipients and the inhomogeneity scores were calculated. The difference between the scores of transplant recipients surviving less than 12 months and those of control subjects were not statistically significant. One year after transplantation, the inhomogeneity score increased progressively. The scores of transplant patients in the second and third years after transplant were similar to those of single-vessel CAD patients. Three years after transplant the scores were greatly increased. Thus, our data suggest that the progressive nature of graft vasculopathy also exists in Chinese heart transplant recipients. The progressive Tl-201 abnormalities may be one of the early signs of graft vasculopathy.
Adolescent↗
ECG data compression using truncated singular value decomposition.
The method of truncated singular value decomposition (SVD) is proposed for electrocardiogram (ECG) data compression. The signal decomposition capability of SVD is exploited to extract the significant feature components of the ECG by decomposing the ECG into a set of basic patterns with associated scaling factors. The signal informations are mostly concentrated within a certain number of singular values with related singular vectors due to the strong interbeat correlation among ECG cycles. Therefore, only the relevant parts of the singular triplets need to be retained as the compressed data for retrieving the original signals. The insignificant overhead can be truncated to eliminate the redundancy of ECG data compression. The Massachusetts Institute of Technology-Beth Israel Hospital arrhythmia database was applied to evaluate the compression performance and recoverability in the retrieved ECG signals. The approximate achievement was presented with an average data rate of 143.2 b/s with a relatively low reconstructed error. These results showed that truncated SVD method can provide an efficient coding with high-compression ratios. The computational efficiency of the SVD method in comparing with other techniques demonstrated the method as an effective technique for ECG data storage or signals transmission. Index Terms-Data compression, electrocardiogram, feature extraction, quasi-periodic signal, singular value decomposition.
Algorithms↗
Perfusionist-transmitted bacterial mediastinitis in a heart transplant recipient.
We report the case of a 56-year-old man who developed bacterial mediastinitis with methicillin-resistant Staphylococcus aureus after undergoing heart transplantation. He had a history of insulin-dependent diabetes mellitus and prior cardiac surgery. To find the source of nosocomial infection, we cultured nasal swab specimens from all hospital personnel involved in this operation. We used antibiotic sensitivity profiling and pulsed-field gel electrophoresis to subtype the involved microorganism. The S. aureus isolates from the patient and the perfusionist were identical to each other and were different from the strains previously found in our hospital. It is almost certain that the S. aureus mediastinitis in this patient was transmitted from the perfusionist. We recommend obtaining cultures from hospital staff members when there is an outbreak of staphylococcal infection.
Bacteriological Techniques↗
Conversion of extracorporeal membrane oxygenation to non-pulsatile left ventricular assist device. Is it out-of-date for non-pulsatile LVAD?
BACKGROUND: Extracorporeal membrane oxygenation (ECMO) provides an immediate support for acute deterioration of hemodynamic and pulmonary status, but what is the best decision for these critical patients? Biventricular assist device (BVAD) or left ventricular assist device (LVAD)? We proposed a protocol of step-by-step conversion from ECMO to LVAD after assurance of the reversibility of right ventricle and pulmonary function. METHODS: After femoral venoarterial ECMO was inserted for the critical patients, the left atrial drainage was added to the ECMO firstly and the femoral arterial inflow was shifted to the ascending aorta for preventing possible peripheral vascular complications. Temporary clamp of right heart drainage was tried to test right heart function 24 to 48 hours later. The sweep gas flow of oxygenator could be reduced gradually to test the pulmonary function. Therefore, the right heart drain and the oxygenator could be withdrawn to become a non-pulsatile LVAD or shift to pneumatic LVAD directly. There were four clinical experiences with successful conversion without temporary right ventricular assist device. RESULTS: All of them were able to convert their ECMO to LVAD smoothly in 8.0+/-2.5 days. Three of them were shifted to non-pulsatile LVAD, and one was converted to HeartMate. All but one could be weaned from the ventilator. No BVAD was needed in these patients. Due to the shortage of donor hearts, only one had the chance to undergo heart transplantation. CONCLUSIONS: The protocol did provide a good guideline for decision-making for those under ECMO support necessitating bridge to transplantation.
Cardiotonic Agents↗
Heart transplantation after mechanical circulatory support.
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Adolescent↗
Roles of the organ transplantation coordination team at the National Taiwan University Hospital.
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Hospitals, University↗