Shu-Hsun Chu

Efficacy of Ultrafiltration in Removing Inflammatory Mediators During Pediatric Cardiac Operations

BACKGROUND Conventional and modified ultrafiltration was used in pediatric cardiac operations to reduce volume overload and total body water. The purpose of this study was to compare the efficacy of these techniques in removing inflammatory mediators during cardiopulmonary bypass. METHODS Fifty pediatric patients undergoing cardiac operations were randomized into a modified or conventional ultrafiltration group. Blood samples were obtained before and after ultrafiltration to assess the plasma concentrations of leukocyte elastase, tumor necrosis factor-alpha, interleukin-6, and interleukin-8. RESULTS Except for plasma concentrations of tumor necrosis factor-alpha in the modified ultrafiltration group, the plasma concentrations of all the mediators measured increased after ultrafiltration in both groups of patients. The volume of ultrafiltrate and the total amounts of tumor necrosis factor-alpha and interleukin-6 removed by ultrafiltration were significantly greater in the modified group. The concentrations of mediators in the ultrafiltrate and the ratio of ultrafiltrate to plasma concentrations of the mediators did not differ between the groups. Ultrafiltration was more efficient in removing tumor necrosis factor-alpha than the other mediators. CONCLUSIONS The efficacy in removing the inflammatory mediators generated during cardiopulmonary bypass did not differ between modified and conventional ultrafiltration.

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.

Thyroid hormone changes cardiovascular surgery and clinical implications

Abstract Alterations in serum concentrations of total triiodothyronine (TT 3 ), total thyroxine (TT 4 ), and thyroid-stimulating hormone (TSH) frequently occur in patients with nonthyroidal illnesses. These changes correlate with the severity of the illness and the prognosis. In this study, 44 patients undergoing a cardiovascular operation had significant declines in serum TT 3 and TT 4 levels during cardiopulmonary bypass and thereafter. Serum TT 3 and TT 4 concentrations reached their nadir at 30 minutes after the start of cardiopulmonary bypass with values (mean ± standard error of the mean) of 0.77 ± 0.12 nmol/L (50.4 ± 7.6 ng/dL) and 68.2 ± 10.2 nmol/L (5.30 ± 0.79 μg/dL), respectively. The mean serum concentrations of TSH and TT 4 returned to preoperative levels by the sixth day after operation, whereas TT 3 levels remained low throughout the study period. The patients whose recovery was uneventful had higher serum TT 3 , TT 4 , and TSH levels than those who had complications or died. The trend toward recovery was initiated by a sharp increase in the serum TSH level and increases in serum TT 3 and TT 4 concentrations on the fourth day after operation. Patients with complications either did not show these changes or had only a transient increase in TT 3 and TT 4 levels. All of the patients had a normal serum free T 4 level before anesthesia. Those with an uneventful recovery had a higher serum free T 4 level on the sixth day after operation than those with complications. Two patients in the latter group had serum free T 4 levels less than normal at that time. The alterations in serum TT 4 , TT 3 , and TSH concentrations has no correlation with drugs (furosemide, dopamine hydrochloride, dobutamine hydrochloride, isoproterenol hydrochloride, norepinephrine, or epinephrine) administered during the study period. In summary, serum TT 3 , TT 4 and TSH levels declined in patients undergoing a cardiovascular operation, especially in those who had complications or died. The administration of catecholamines or furosemide was not an important factor in the development of abnormal thyroid function test results in our study.

Successful resuscitation of acute massive pulmonary embolism with extracorporeal membrane oxygenation and open embolectomy

Acute massive pulmonary embolism is usually fatal if not treated aggressively, but the management is not standardized. Open pulmonary embolectomy retains a role in the treatment of this disastrous disease. Extracorporeal membrane oxygenation has been used for cardiopulmonary support in some patients with life-threatening pulmonary embolism. This article details our experience of a 58-year-old woman suffering from acute cardiopulmonary collapse caused by massive pulmonary embolism. Under extracorporeal membrane oxygenation support, the patient received pulmonary angiography and underwent open embolectomy for a definitive treatment.

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.

Extracorporeal membrane oxygenation for perioperative cardiac allograft failure

The utility of mechanical support in pretransplant stabilization and postcardiotomy shock is well established, but its use in perioperative cardiac allograft failure (PCAGF) rescue has not been well documented. Ventricular assist devices (VADs) have been applied to PCAGF rescue with acceptable results. However, studies have not described the results of using extracorporeal membrane oxygenation (ECMO) in PCAGF. We evaluated the outcome of PCAGF rescue with ECMO. A retrospective review of 204 consecutive heart transplants revealed 19 cases of PCAGF requiring ECMO rescue. Donor-, surgery- and ECMO-related variables were evaluated for association with operative mortality, success of weaning, and survival rate. Transplant recipients included 14 males and 5 females with median age of 44.2 years. Weaning rate was 84.2% and survival rate was 52.6%, with duration of ECMO support 157 ± 129 hours. Long ischemic time is a PCAGF risk factor (206.8 ± 96.1 minutes vs. 158.3 ± 60.8 minutes in non-PCAGF, p < 0.05). PCAGF etiology included primary graft failure (n = 7); right heart failure secondary to pulmonary hypertension, coagulopathy/intraoperative hemorrhage (n = 7); and sepsis (n = 2). Compared with data from VAD-supported PCAGF, ECMO had a better weaning and graft survival rates (p < 0.05). ECMO is another choice for PCAGF rescue. It has an acceptable survival rate and may be considered instead of VADs as a first-line rescue for PCAGF.

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.

Clinical Features and Outcome of Tuberculosis in Solid Organ Transplant Recipients

Background:Taiwan is an area with moderate to high incidence of Mycobacterium tuberculosis infection. The risk of M tuberculosis infection in transplantation recipients is considered to be significant. Our aim in this study was to investigate the clinical spectrums of M tuberculosis–infected transplantation recipients in a southeast Asian country, Taiwan. Methods:We retrospectively analyzed the demographic data, clinical features, treatment, and outcome of M tuberculosis infection in kidney, heart, and liver transplant recipients from May 1996 to April 2005 at the National Taiwan University Hospital. Results:Fifteen patients who had received solid organ transplantation developed tuberculosis (kidney = 6, heart = 7, liver = 2). The median duration from transplantation to diagnosis of tuberculosis was 31 months. The cumulative incidence of post-transplantation tuberculosis was 2.0% (15/760), ie, ∼3 times that of the general population. Ten patients (66.7%) had pulmonary tuberculosis, 1 (6.7%) had extrapulmonary tuberculosis, and 4 (26.7%) had disseminated tuberculosis. Nine patients completed the anti-tuberculosis treatment; the median treatment duration was 12 months (pulmonary: 9 months; extrapulmonary: 13.5 months). No treatment failure was noted in patients receiving the complete treatment course. The graft failure and mortality rates of post-transplantation tuberculosis were 13.3% each (2/15). The tuberculosis-associated mortality rate was 6.7% (1/15). Conclusions:Cumulative incidence of tuberculosis was slightly higher in transplant recipients than in the general population in Taiwan. Conventional 4-combined anti-tuberculosis regimen for 12 months can treat the potentially fatal infection successfully in post-transplantation tuberculosis patients without recurrence.

Low incidence of transplant coronary artery disease in chinese heart recipients

OBJECTIVES This study sought to assess the incidence of transplant coronary artery disease (CAD) in Chinese heart recipients. BACKGROUND The prevalence of transplant CAD detected by angiography at 1, 2 and 4 years after heart transplantation was 11%, 22% and 45%, respectively. The incidence of transplant CAD in Chinese heart recipients has not been reported. METHODS For those recipients surviving for more than 1 year after transplantation, coronary angiography was performed annually for surveillance of transplant CAD. The recipient characteristics, donor characteristics, rejection episodes, medication and human leukocyte antigen (HLA) mismatches were recorded. RESULTS Fifty patients were included in this study. Thirteen (26%) recipients had ischemic heart disease. Two patients (4%) had active cytomegalovirus (CMV) infection after transplantation. The mean number of rejection episodes in the 1st year after transplantation was 1.15. Among 47 patients with complete data of donor and recipient histocompatibility antigens, there were seven patients (14.9%) with two or fewer HLA mismatches. Among 74 angiograms of 50 patients reviewed, only one patient had discrete stenosis less than 50% in the middle portion of the left anterior descending artery at 1 year after transplantation. The cumulative incidence of transplant CAD was 2% at 1 year and 2% at 2 and 4 years after transplantation. CONCLUSIONS The incidence of transplant CAD was low in Chinese heart transplant recipients. Low percentage of ischemic heart disease in recipients, low occurrence of active CMV infection and rejection episodes after transplantation, less racial disparity, and lower HLA mismatches may be the important factors.

Hyperbilirubinemia after cardiac operation: Incidence, risk factors, and clinical significance

Three hundred and two consecutive patients who had undergone cardiac operation for various cardiac lesions were studied prospectively to evaluate the incidence, risk factors, and the associated mortality of postoperative hyperbilirubinemia after cardiopulmonary bypass. Concentrations of the serum total (conjugated and unconjugated) bilirubin, alanine aminotransferase, aspartate aminotransferase, lactate dehydrogenase, alkaline phosphatase, albumin, globulin, and serum haptoglobin were measured before the operation and again on the first, second, and seventh postoperative days. Postoperative hyperbilirubinemia was defined as occurrence of a serum total bilirubin concentration of more than 3 mg/dl in any measurement during the postoperative period. Logistic regression was done to identify possible risk factors for postoperative hyperbilirubinemia. Overall incidence of postoperative hyperbilirubinemia was 35.1%; the incidence of postoperative hyperbilirubinemia was higher in patients whose valves were replaced with mechanical prostheses than in those without prostheses (p < 0.00001). In patients with postoperative hyperbilirubinemia, 70% of the increase of total bilirubin on the first postoperative day came about from an increase in unconjugated bilirubin. Serum haptoglobin decreased significantly at the same time (p < 0.01). Development of the postoperative hyperbilirubinemia was associated with a higher mortality (5.6% versus 0.5%, p < 0.01) and higher frequency of use of intraaortic balloon counterpulsation, especially for patients in whom the highest postoperative total bilirubin occurred after the first 2 days. The numbers of valves replaced, preoperative right atrial pressure, and preoperative total bilirubin concentration are the significant risk factors that, in combination, correctly predict the occurrence of postoperative hyperbilirubinemia in 80% of the patients. We concluded that postoperative hyperbilirubinemia results mainly from an increase in unconjugated bilirubin and is associated with higher mortality, especially for patients in whom highest postoperative total bilirubin occurred late after operation. Patients with the higher preoperative right atrial pressure and total bilirubin level who then underwent multiple valve replacement procedures are at greater risk for development of postoperative hyperbilirubinemia.