PubMed Health⌕ Search

Biomedical subjects

N K Chou

Publications and source records attributed to N K Chou.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneous heart and kidney transplantation for combined cardiac and renal failure.

Simultaneous heart and kidney transplantation (SHKT) is feasible for combined cardiac and renal failure. Herein we reviewed our 10-year experience in SHKT. Six patients underwent SHKT from June 1995 to December 2004. Their ages ranged from 13 to 63 years old with a mean of 45.5 +/- 15.8 years. They were all men except one girl, who was the youngest (aged 13) who suffered from dilated cardiomyopathy with congestive heart failure and chronic renal failure due to systemic lupus erythematosus. Because of aggravating heart failure, she changed from hemodialysis to peritoneal dialysis. Because of intractable heart failure, she underwent SHKT from a 24-year-old female donor. All received hemodialysis before SHKT. The indications for heart transplantation included dilated cardiomyopathy (n = 3), ischemic cardiomyopathy (n = 1), cardiac allograft vasculopathy (n = 1), and cardiac allograft failure (n = 1). The immunosuppressive protocol and rejection surveillance were these employed for heart transplantation. No operative mortality was noted in this study. The 1-year and 5-year survival rates were the same, 83%. The 10-year survival rate was 55%. No cardiac or renal allograft rejection was noted. No renal allograft loss was noted. There were two late mortalities: the one, who underwent redo heart transplantation for coronary artery vasculopathy died of cardiac allograft failure 1 year after SHKT. The other patient died of massive ischemic necrosis of the intestine at 6 years after SHKT. Our experience showed that SHKT had good short- and long-term results without increasing immunosuppressive doses. End-stage failure of either the heart or the kidney did not preclude heart plus kidney transplantation.

Adult↗
PubMed2006

Sparing immunosuppression in heart transplant recipients with severe sepsis.

This study described an analysis of severe sepsis among heart transplantation recipients who were treated by sparing all immunosuppressants. Sepsis leading to multiple organ failure (MOF) in heart transplantation has a high mortality. This retrospective study of 190 patients who underwent heart transplantation from 1993 to 2004 included 12 who had severe sepsis with MOF who were treated by sparing all immunosuppressants. Half of them survived after sparing all immunosuppressants with intensive endomyocardial biopsy. Only one case needed pulse therapy for an acute rejection episode. The most common bacterial infectious episodes were caused by methicillin-resistant Staphylococcus aureus (n = 3). All sepsis episodes occurred in the first month after heart transplantation except in one case, which occurred 6 years after heart transplantation. There was a 50% survival rate of heart transplantation recipients who experienced MOF due to severe sepsis and were treated by sparing all immunosuppressants under a program of intensive endomyocardial biopsy.

Bacterial Infections↗
PubMed2006

Successful treatment of hepatitis B virus infection with Lamivudine after heart transplantation.

Patients with hepatitis B virus (HBV) infection have a higher morbidity and mortality after heart transplantation (HT). HBV infection is endemic in Taiwan. We studied the effect of lamivudine treatment of HBV infection after HT. From July 1987 to July 2005, 252 patients underwent HT. All recipients and donors underwent routine screening of hepatitis B surface antigen (HBsAg), hepatitis B e antigen, antibody to hepatitis B surface antigen, antibody to hepatitis B core antigen, antibody to hepatitis B e antigen, and an alanine aminotransferase (ALT) level before HT. When ALT was two times greater than the upper limit of normal or serum bilirubin was higher than 3 mg/dL in HBsAg-positive patients, HBV-DNA were checked by a branched DNA assay or polymerase chain reaction. When HVB-DNA was greater than 100,000 copies/mL, lamivudine (100 mg per day) was prescribed indefinitely. There were 14 patients under lamivudine treatment after HT, among whom, none suffered severe adverse reactions from lamivudine. Four patients died: one due to end-stage cirrhosis while awaiting liver transplantation at 14 months after HT. Two died of sudden death at 54 months and 138 months after HT. Another died of diffuse B cell lymphoma at 62 months after HT. All the survivors have normal ALT and undetectable HBV-DNA after lamivudine treatment. But the YMDD mutant was detected in two patients. With successful treatment of HBV infection in HT, it is not necessary to exclude HBV infection patients from HT.

Adult↗
PubMed2006

Bone mineral density in long-term Chinese heart transplant recipients: a cross-sectional study.

Osteoporosis, which usually peaks during 6 to 12 months after transplantation, remains an important concern after heart transplantation. Immunosuppressants contribute to this phenomenon. Glucocorticoids are well documented to cause bone loss, but the role of cyclosporine (CsA) remains controversial, especially among long-term recipients on low doses of steroid. We herein report a cross-sectional study of bone mineral density (BMD) among long-term Chinese heart transplant recipients. We enrolled 41 patients of mean age 50.15 +/- 13.58 years with a mean follow-up of 57.02 months. Lumbar spine and femoral neck BMD were measured by dual energy x-ray absorptiometry. Trough CsA levels (C(0)) and markers of mineral metabolism, including bone-specific alkaline phosphatase and urinary N-telopeptide, were determined by immunoassay. Sixty six percent of subjects showed bone loss at the femoral neck, significantly more than those in the lumbar spine. Those receiving a higher CsA dosage (<2.5 mg/kg/d) showed greater femoral neck BMD, but lower serum creatinine values. Our results demonstrated that bone loss remains long after transplantation, though bone markers are within normal limits.

Adult↗
PubMed2006

Extracorporeal membrane oxygenation hybrid with various ventricular assist devices as double bridge to heart transplantation.

Ventricular assist devices (VAD) have benefitted patients with end-stage heart failure as a bridge to heart transplantation (HTx). We present our experience with HTx after an extracorporeal membrane oxygenation (ECMO) hybrid with various ventricular assist devices (VAD). From May 1996 to December 2003, mechanical circulatory support with a Biopump VAD was performed in eight patients, HeartMate left VAD in eight patients, and Thoratec VAD in eight patients. Before VAD implantation, 19 patients maintained their circulation with ECMO. Half of the 24 patients were implanted with VAD to await a suitable donor for HTx. We observed that half of the patients supported by ECMO hybrid with various VAD awaited a suitable donor for HTx. In our experience, we recommend the application of ECMO for short-term support within 1 week and the Biopump VAD, Thoractec VAD, or HeartMate VAD for medium-term or long-term support as a bridge to HTx.

Adult↗
PubMed2006

Heart retransplantation for heart allograft failure in Chinese heart transplant recipients: NTUH experience.

We investigated the short- and long-term results after heart retransplantation in terms of different causes of heart allograft failure. We sought to establish the data of heart retransplantation in Chinese compared with Western counterparts due to differences in heart allograft vasculopathy. From March 1995 to May 2005, eight heart transplantation recipients with allograft failure underwent retransplantation. Heart allograft failure was due to coronary vasculopathy (CAV) in six patients (75%) and acute rejection in two patients (25%). The mean interval to retransplantation was 32 to 84 months (mean 54.3 months). There were five patients who survived after heart retransplantation for CAV and no patient survived after an earlier diagnosis of acute rejection. Heart retransplantation is a feasible method with acceptable long-term survival rate for heart allograft failure. After careful pretransplant evaluation, retransplantation is acceptable. The survival after retransplantation for CAV is notably great than that after acute rejection. Heart retransplantation is the only way for patients who have cardiac allograft failure to achieve long-term survival.

Adult↗
PubMed2006

Single-center experience of pediatric heart transplantation in taiwan.

Heart transplantation (HTx) is a treatment for end-stage heart failure or a complex or inoperable congenital defect. The long-term survival and the adequate donor to recipient body weight (D/R BW) ratio remain to be determined. From March 1995 to May 2004, 14 children (6 months-16 years of age) underwent HTx due to underlying diseases of idiopathic dilated cardiomyopathy (n = 10; 71.4%), congenital heart disease (n = 3; 21.4%), and Kawasaki disease (n = 1; 7.1%). Donor-recipient body weight ratio ranged from 0.89 to 3.9. Big heart syndrome was present in one patient when D/R BW ratio was more than 3. Actuarial survival was 92.9% at 5 years after transplantation. Only the one patient who had Kawasaki disease died due to early primary graft failure. HTx is a feasible method with good long-term survival rates for end-stage heart failure or for complex or inoperable congenital defects. After careful pretransplant evaluation, a high D/R BW ratio (more than 3) is acceptable.

Body Weight↗
PubMed2004

Adaptive processing bandwidth adjustment for laser Doppler flowmetry.

A novel laser Doppler flowmetry scheme is reported that adjusts the processing bandwidth adaptively to optimise the estimation of flow. To obtain an adequate processing bandwidth, the Doppler spectra is first fitted to the Lorentzian function, and the bandwidth at half the maximum of the Lorentzian function is used as an indicator of the major frequency range of the signal. The processing bandwidth is then tuned accordingly, and a frequency-weighted algorithm is applied to compute the fluid velocity. To investigate the influence of the processing bandwidth, an in vitro experiment was performed. In the experiment, the flow rate was controlled at constant velocity in the range from 0 to 18.52 mm s(-1), and the fluid velocity indices were calculated using adaptive and fixed processing bandwidths, respectively. The results showed that the adaptive processing bandwidth adjustment, not only significantly reduced the biological zero (9.6% of the case using 100 kHz bandwidth), but also enhanced the sensitivity of the laser Doppler measurement (over 20%) and linearly responded to a wider velocity range (R2 = 0.979 for velocity from 0 to 18.52 mm s(-1)).

Algorithms↗
PubMed2004

A limited sampling strategy for the estimation of 12-hour cyclosporine neoral area under the curve in Chinese cardiac transplant recipients.

INTRODUCTION: This study determined the accuracy of a limited sampling strategy to predict the 12-hour cyclosporine neoral (CsA) area-under-the-curve (AUC) to provide a practical method for more accurate therapeutic drug monitoring (TDM) of CsA in Chinese heart transplant recipients. METHODS: Blood samples were collected at 0 (before the dose), and 0.5, 1, 2, 3, 4, 6, 8, 10, as well as 12 hours after CsA oral administration in 13 de novo heart recipients receiving oral CsA bid after rabbit antithymoglobulin sequential immuno-induction. Pharmacokinetics were analyzed for the first dose (PK-1) and the steady state dose (PK-2, 1 month after transplantation). The limited sampling strategies included single-point, 2-point, and 3-point prediction of AUC using multiple linear regression analyses. RESULTS: Comparing the AUC/mg dose, PK-1 was much lower than PK-2 (25.2 +/- 11.4 ng x h/mg x mL vs 45.4 +/- 12.9 ng x h/mg x mL; P = .0005 using paired t test). The correlations of each single-point blood level of PK-1 with the AUC were lower than those of the corresponding sampling time in PK-2. In the PK-2 study, C4 had the best correlation (r2 = 0.732; P = .00) as a single-point to predict AUC, but the 2-point C2 + C12 had a higher correlation (r2 = 0.937; P = .00). Among the 3-point combinations, C2 + C4 + C12 showen the best prediction (r2 = 0.982; P = .00) of the AUC in PK-2. CONCLUSION: The bioavailability of CsA was lower in PK-1 than in PK-2. At steady state, we recommend C2 + C12 to predict AUC because it is accurate and not labor-intensive.

Adult↗
PubMed2004

Therapeutic drug monitoring of tacrolimus in cardiac transplant recipients: a comparison with cyclosporine neoral.

UNLABELLED: This study compares the pharmacokinetics of tacrolimus (TAC) and cyclosporine Neoral (CsA) in cardiac transplant recipients. METHODS: Twenty-six de novo cardiac recipients were prospectively and randomly assigned to receive oral TAC- or CsA-based regimens after 5 to 6 days of rabbit antithymocyte globulin induction. Blood samples were collected at 0 (before the dose) and 0.5, 1, 2, 3, 4, 6, 8, 10, as well as 12 hours after drug administration. The pharmacokinetics of the first dose (PK-1) and at steady state (PK-S, 1 month after transplantation) were analyzed. RESULTS: Comparing the AUC per milligram dose, there was no significant difference between PK-1 and PK-S among TAC (46.0 +/- 24.3 ng x h/mg x mL versus 69.0 +/- 43.9 ng x h/mg x mL, P = .15 by paired t-test), but a significant difference in CsA (25.2 +/- 11.4 ng x h/mg x mL versus 45.4 +/- 12.9 ng x h/mg x mL, P = .0005 by paired t-test). This means better TAC absorption in the early post-heart transplant period. Using a single-point blood level to predict AUC, TAC showed a significantly higher correlation than CsA at all corresponding sampling times. Besides, C12 in both PK-1 and PK-S of TAC displayed good correlations to the AUC (r2 = .895, P = .00 in PK-1 and r2 = .81, P = .00 in PK-S). The TAC trough level was accurate enough to predict the AUC. CONCLUSION: The pharmacokinetic profile of TAC is more reliable than that of CsA in the early post-heart transplant period. A high correlation of trough blood levels with AUC omits the requirement for a multiple sampling strategy to more accurately measure AUC as is needed with CsA.

Antilymphocyte Serum↗
PubMed2004

Efficacy and safety of tacrolimus versus cyclosporine microemulsion in primary cardiac transplant recipients: 6-month results in Taiwan.

INTRODUCTION: This study compared the efficacy and safety of a tacrolimus (TAC)-based with a cyclosporine (CsA)microemulsion-based immunosuppressive regimen in primary cardiac transplantation. METHODS: Heart recipients were randomly assigned to receive either TAC or CsA regimen after sequential induction with rabbit anti-thymoglobulin. Endomyocardial biopsies were performed at weeks 1, 2, 3, and 4 and months 2, 3, and 6. RESULTS: Among 21 adult patients (TAC, 11; CsA, 10) in this study, patient survival rates were 100% in both groups at the end of 6 months. One patient (9%) in the TAC group experienced acute rejection (ISHLT > or = 1B) versus 6 patients (60%) in the CsA group (P = .02). The effects on hematology, biochemistry, cytomegalovirus infection, and hemodynamics were similar in both groups except for better lipid profiles in the TAC group. There were no significant differences in severe adverse events. CONCLUSION: The TAC-based regimen had a lower risk of acute rejection compared with CsA in heart transplant recipients. The safety profiles were similar in both groups. Therefore, TAC is an alternative to CsA as a primary maintenance immunosuppressant in heart transplantation.

Adult↗
PubMed2004

Influence of UNOS status on chance of heart transplantation and posttransplant survival.

UNLABELLED: This study was designed to compare the chance of heart transplantation (HTx) and survival among patients in different UNOS statuses in Taiwan. METHODS AND RESULTS: From 1996 to 2002, among 203 patients on the heart transplant waiting list, 127 patients had undergone HTx up to December 2002 with 71 dead while waiting, and 5 still alive without transplantation. This study included those 198 patients who had either undergone HTx or who died. At the time of registry, 40 patients were at status IA, 57 at IB, and 101 at II. Nineteen (47.5%) of 40 status IA patients underwent HTx with a mean waiting time of 92 +/- 116 days and median waiting time of 35 days. The 1-month survival was 84%, and 1-year survival was 58%. Seven (64.9%) of 57 status IB patients underwent HTx with a mean waiting time of 85 +/- 100 days and a median waiting time of 40 days. Both 1-month and 1-year survivals were 92%. Seventy-one (70.3%) patients among 101 status II patients underwent HTx. Their mean waiting time was 134 +/- 135 days and median waiting time was 86 days. Their 1-month survival was 95%, and 1-year survival was 85%. CONCLUSION: Although UNOS status IA patients had a shorter waiting time, their chance to undergo HTx was lower than those in either status IB or status II. The UNOS status IA heart-waiting patients showed lower posttransplant 1-month and 1-year survival rates.

ABO Blood-Group System↗
PubMed2003

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↗
PubMed2001

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↗
PubMed2001

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↗
PubMed2001

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↗