Coagulation abnormalities in patients with cyanotic congenital heart disease

[Intensive care management of critically ill adults with congenital heart disease]

Due to improvements in cardiac surgery and perioperative care the number of adults with congenital heart disease is continuously growing. The perioperative and intensive care management of these patients is a challenge due to the variety of pathologies and surgical options as well as the complex pathophysiology. Many patients develop organ dysfunction with time and many require multiple cardiac operations as well as non-cardiac interventions during adulthood. While these patients are best treated in dedicated tertiary centers that provide a multidisciplinary expertise, basic knowledge of this population is important for everyone involved in acute medical care. This review will discuss some general aspects of adults with congenital heart disease such as pulmonary hypertension, Eisenmenger syndrome, cyanosis, pregnancy and perioperative care, with a special focus on the management of critically ill patients.

Validation of the megakaryocyte fragmentation theory of finger clubbing in patients with cardiopulmonary diseases

Dickinson and Martin had proposed that finger clubbing is caused by distal impaction of large-sized platelets that escape physiological fragmentation in lung vasculature. Empirical evidence to support this theory, however, is limited and conflicting. Moreover, this theory has not been verified in patients with lung diseases. We conducted a cross-sectional analytic study to validate the megakaryocyte fragmentation theory in patients with cardiopulmonary diseases. We studied four groups - patients with cyanotic heart diseases and clubbing (n = 20); patients with non-malignant lung diseases and clubbing (n = 25); patients with non-malignant lung diseases but no clubbing (n = 25); and healthy individuals (n = 25). We measured the distal phalangeal depth ratio, estimated the platelet volume indices, and examined the peripheral blood smear for the presence of large platelets. We found that patients with clubbing due to cyanotic heart diseases had a significantly lower platelet count (median [IQR] 201 [157-241] vs. 303 [258-334] × 10(3)/μl; p < 0.001), higher platelet volume (mean difference, Δ [95% CI] = 0.93 fl [0.37-1.49 fl]; p = 0.002) and platelet large cell ratio (Δ = 7.99% [3.71%-12.26%]; p < 0.001) as compared to healthy individuals. They were also significantly more likely to have large platelets on peripheral blood smear as compared to healthy individuals (9/25 vs. 0/25; p = 0.002). However, in patients with lung diseases, irrespective of the presence or absence of clubbing, platelet count and platelet volume indices were not different from healthy individuals. Our findings support the megakaryocyte fragmentation theory of finger clubbing in patients with cyanotic heart diseases. However, this theory does not explain the clubbing seen in non-malignant lung diseases.

Inflammatory cytokines, apoptotic, tissue injury and remodeling biomarkers in children with congenital heart disease

The present study aims to evaluate specific biomarkers involved in congenital heart disease (CHD), and whether there is a significant differences between the levels of these biomarkers in the cyanotic CHD (CCHD) and acyanotic CHD (ACHD). We prospectively measured tumor necrosis factor (TNF-α), interleukin-6 (IL-6), C-reactive protein (CRP), vasoendothelial growth factor (VEGF), troponin T, creatin kinase MB (CKMB), and Caspase 3 levels in 120 consecutive children with CHD (60 cyanotic and 60 a cyanotic with age 1:4 years), and 30 healthy control children. Significant elevated levels of inflammatory markers; TNF-α, IL-6 and CRP was detected in CHD, with percentage increase in cyanotic than a cyanotic subjects as compared to the normal one. Apoptotic biomarker; caspase 3 showed also significant increases in CCHD than ACHD. In addition, tissue injury mechanisms included troponin T and CKMB, exhibited significant increase in cyanotic than a cyanotic CHD. The present results demonstrate also, significant enhancement in remodeling process (VEGF), in cyanotic than a cyanotic patients. Thus, it could be concluded that, the children with CCHD were shown to have elevated levels of inflammatory cytokines, caspase 3, troponin T, and CKMB as these biomarkers may implicated in cardiac functional status.

Approach to a child with bleeding in the emergency room

A bleeding child is a cause of great concern and often, panic, for parents and pediatricians alike. Causes of bleeding could be trivial or secondary to an underlying bleeding disorder or a potentially serious systemic illness. Based on etiology, they can be categorized into disorders affecting platelets or the coagulation cascade and can be inherited or acquired. A systematic approach with relevant clinical history and examination along with appropriate laboratory investigations aid in reaching the diagnosis promptly. Indication and administration of blood products including fresh frozen plasma, cryoprecipitate, random donor and single donor apheresis platelets is elaborated. Management of hemophilia, Von Willebrand disease, disseminated intravascular coagulation and bleeding in cyanotic congenital heart disease, among other causes is outlined. Role of antifibrinolytic therapy, desmopressin and recombinant factor VIIa is briefly described. The review outlines the approach to a bleeding child in the emergency room. Practical points in history, examination, investigations and management are discussed. Management in resource constraint setting of developing countries is addressed.

Bleeding and Thrombotic Emergencies in Pediatric Cardiac Intensive Care

Children in the cardiac intensive care unit (CICU) with congenital or acquired heart disease are at risk for hematologic complications, both hemorrhage and thrombosis. The overall incidence of hematologic complications in the CICU is unknown, but risk factors and target groups have been identified where the essential physiologic balance between bleeding and clotting has been disrupted. Although the best management of life-threatening bleeding and clotting is prevention, the cardiac intensivist is often faced with managing life-threatening hematologic events involving patients from within the unit or those who present from outside. Part I of this review deals with the propensity of children with congenital and acquired heart disease to complications of both bleeding and clotting, and includes discussions of perioperative bleeding, thromboses in single-ventricle patients, clotting of Blalock-Taussig shunts and thrombotic complications of mechanical valves. Part II deals with the subject of stroke in children with heart disease. Part III reviews monitoring the effectiveness of anticoagulation and thrombolysis in the CICU. Currently available diagnostics modalities, medications and management strategies are reviewed and future directions discussed.

Thrombolysis With Recombinant Tissue Plasminogen Activator in 7 Children

The information about the thromboembolic events, the optimal treatment choice, the dose, and duration of antithrombotic therapy in children are limited. More clinical data are required. Recombinant tissue plasminogen activator (r-tPA) is increasingly used in pediatric thrombosis. We retrospectively analyzed the clinical course of 7 children (9.3 ± 2.1 years; 34 days to 16 years) with arterial thrombosis (n = 1) and intracardiac thrombosis (n = 6). The children were treated with r-tPA. The dose ranged between 0.2 and 0.4 mg/kg per h infused for 3 to 4 hours. This dose was repeated between 2 to 7 times till the thrombolysis was achieved. Treatment side effects were closely monitored. Complete clot lysis was achieved in all cases. None of them had severe bleeding except mild recurrent epistaxis occurring in 2 cases. In conclusion, r-tPA is an effective and safe therapy under close hemostatic control in children.

Tetralogy of Fallot: perioperative anesthetic management of children and adults

Tetralogy of Fallot (TOF) is a common congenital heart defect in children. Perioperative considerations include preoperative preparation for surgery, intraoperative anesthetic management, and common postoperative issues in the intensive care unit. Surgical debates have shifted away from 2-stage versus single-stage repairs to debates of how surgery to limit pulmonary insufficiency (PI) may have significant long-term impact as the child grows. There are many adult survivors of TOF repair in infancy who now present with a unique set of problems related to PI and right ventricular dysfunction. These adults provide new insights into congenital heart disease (CHD) and how management strategies early in life may have significant implications much later in life. Patients with complex CHD should have lifelong follow-up, so our knowledge will continue to improve, and the best possible care can be provided for these patients.

Point-of-care assessment of platelet aggregation in paediatric open heart surgery

BACKGROUND

Congenital heart disease (CHD) is associated with complex coagulation abnormalities. Platelet aggregability has not been investigated in detail in children with acyanotic and cyanotic malformations undergoing open heart surgery. The method of whole-blood multiple electrode aggregometry (MEA) appears suitable for rapid platelet analysis in children, for example, because of small sample volumes. We investigated perioperative evolution of platelet aggregation by means of MEA in children with CHD.

METHODS

Fifty children with acyanotic or cyanotic malformations were included in a prospective observational study. Laboratory testing was assessed before anaesthesia, and during and after surgery until the fifth postoperative day. MEA was performed in hirudin-anticoagulated blood using adenosine diphosphate (ADP), arachidonic acid, and thrombin receptor-activating peptide for platelet activation. Surgical variables, bleeding volumes, and transfusion requirements were documented during hospital stay.

RESULTS

Mean platelet count was within the normal range in all patients with no intergroup differences. Before surgery, aggregation to all agonists was within the age-adjusted normal range in cyanotic children and was statistically significantly higher compared with acyanotic children. Platelet aggregation decreased significantly during surgery in both groups followed by a slow recovery not reaching baseline levels. Bleeding and platelet transfusions were higher in the cyanotic group. Transfusion requirements correlated with ADP-induced platelet aggregation.

CONCLUSIONS

These results indicate higher blood loss, despite better platelet aggregation in cyanotic patients compared with acyanotic patients. MEA alone might not be suitable for predicting increased perioperative blood loss.

Treatment and monitoring of coagulation abnormalities in children undergoing heart surgery

Bleeding is a considerable clinical problem during and after pediatric heart surgery. While the primary cause of bleeding is surgical trauma, its treatment is often complicated by the presence of coagulopathy. The principle causes of coagulopathy are discussed to provide a context for treatment. The role of laboratory and point of care tests, which aim to identify the cause of bleeding in the individual patient, is also discussed. An attempt is made to examine the current evidence for available therapies, including use of blood products and, more recently proposed, approaches based on human or recombinant factor concentrates.

Adult congenital heart disease

For a decade now, it has been recognized that optimal management of adult congenital heart disease (ACHD) requires a skilled multidisciplinary team. The size and complexity of the population of adults with congenital heart disease (CHD) are increasing. This article reviews the general considerations for giving an anesthetic to an adult with CHD for cardiac or noncardiac surgery and provides further elaboration for a variety of complex patient types. Lastly, the advantages of an organized multidisciplinary approach to patients with ACHD are discussed.

Contraception in women with congenital heart disease

The present study reports on contraceptive use, methods used, and counseling received on contraceptive issues for women with congenital heart disease and provides a brief review of current knowledge of the risks in relation to the different cardiac situations encountered with these specific patients. A total of 536 consecutive adult women with congenital heart disease (median age 29 years) were recruited from 2 tertiary care centers. They underwent a clinical assessment and completed a questionnaire regarding their contraceptive use. Oral contraceptives, condoms, and intrauterine devices were the most commonly used methods. Pregnancy occurred in almost every tenth woman despite the use of contraception. We identified a substantial number of women (20%) who were presently using contraceptive methods that were contraindicated for their specific cardiac condition. Additionally, a high proportion of patients (28%), in the group with high pregnancy-associated risks, were not using contraception despite having a sexual relationship. In our study, 43% of the women had not been counseled about contraception, and 48% had not been informed of the pregnancy-related risks by their treating physician. In conclusion, timely and competent counseling about contraception is important for women with congenital heart disease. Collaboration between cardiologists and gynecologists should be strengthened. Failure to give adequate family planning advice to this patient group could have hazardous consequences, causing an unnecessary risk to mother and child.

The relationship among thromboelastography, hemostatic variables, and bleeding after cardiopulmonary bypass surgery in children

BACKGROUND

Mediastinal bleeding is common after pediatric cardiopulmonary bypass (CPB) surgery. Thromboelastography (TEG) may predict bleeding and provide insight into likely mechanisms. We aimed to (a) compare perioperative temporal profiles of TEG and laboratory hemostatic variables between patients with significant hemorrhage (BLEED) and those without (CONTROL), (b) investigate the relationship between TEG variables and routine hemostatic variables, and (c) develop a model for prediction of bleeding.

METHODS

TEG and laboratory hemostatic variables were measured prospectively at 8 predefined times for 50 children weighing <20 kg undergoing CPB.

RESULTS

Patients who bled demonstrated different TEG profiles than those who did not. This was most apparent after protamine administration and was partly attributable to inadequate heparin reversal, but was also associated with a significantly lower nadir in mean (sd) fibrinogen for the BLEED group compared with CONTROL group: 0.44 (0.18) and 0.71 (0.40) g/L, respectively (P = 0.01). Significant nonlinear relationships were found between the majority of TEG and laboratory hemostatic variables. The strongest relationship was between the maximal amplitude and the platelet-fibrinogen product (logarithmic r(2) = 0.71). Clot strength decreased rapidly when (a) fibrinogen concentration was <1 g/L, (b) platelets were <120 x 10(9)/L, and (c) platelet-fibrinogen product was <100. A 2-variable model including the activated partial thromboplastin time at induction of anesthesia and TEG mean amplitude postprotamine discriminated well for subsequent bleeding (C statistic 0.859).

CONCLUSIONS

Hypofibrinogenemia and inadequate heparin reversal are 2 important factors contributing to clot strength and perioperative hemorrhage after pediatric CPB. TEG may be a useful tool for predicting and guiding early treatment of mediastinal bleeding in this group.

Defining the role of recombinant activated factor VII in pediatric cardiac surgery: where should we go from here?

OBJECTIVES

Postoperative hemorrhage is a recognized complication of pediatric cardiac surgery. Both the immature coagulation system and increased susceptibility to hemodilution increase the likelihood of pediatric patients developing coagulopathy when compared with adult counterparts. Treatment options remain limited. Recombinant factor VII (rFVIIa) is a hemostatic agent increasingly used to reduce hemorrhage in other surgical settings, the role of which is unclear in this population. This article systematically reviews the published literature on the use of rFVIIa in pediatric cardiac surgery.

DATA SOURCES AND STUDY SELECTION

A systematic literature search identified reports of rFVIIa administration in pediatric patients undergoing cardiac surgery. Where possible, individual patient-specific data were extracted and pooled statistical analysis was performed.

DATA EXTRACTION AND SYNTHESIS

Twenty-nine articles reporting on the administration of rFVIIa to 169 patients were identified. rFVIIa has been administered to patients with predefined congenital abnormalities of hemostasis to arrest hemorrhage refractory to other interventions and prophylactically in the hope of reducing blood loss. Treatment regimens vary widely, in terms of both first and cumulative dose. Data on chest tube blood loss and two markers of coagulation were pooled and analyzed, and significant improvements were demonstrated. Mortality was 4.4% for the entire cohort but 20% of patients on extracorporeal membrane oxygenation suffered significant thromboembolic complications.

CONCLUSIONS

rFVIIa has an increasingly accepted role in the management of patients with congenital coagulopathies undergoing major surgery. However, randomized trials are required to define the role of rFVIIa as an adjunct to control major hemorrhage in the pediatric cardiac surgical population. Any future work must focus not only on benefits but also on patient safety, particularly, risk of morbid thromboembolic complication.

Whole blood coagulation measured by modified thrombelastography (ROTEM) is impaired in infants with congenital heart diseases

Patients with congenital heart disease (CHD) often do have a variety of coagulation abnormalities that results in bleeding diathesis. Our study aimed to determine the impact of cyanosis and CHD on modified thrombelastography parameters, compared with children without CHD. Preoperative blood samples were taken for TEM analyses from a total of 51 infants scheduled for surgery. The following groups were examined: normal patients without CHD, acyanotic patients with acyanotic CHD, and cyanotic patients with CHD and with preoperative hemoglobin values higher than 15 g dl(-1). Mean values of all patient groups as well as all individual values of normal patients were within their normal ranges. Within these limits, however, clots were significantly inferior in cyanotic patients (worse mean values of eight out of 10 measured TEM parameters representing the intrinsic, extrinsic, and plasmatic pathways of coagulation) and in acyanotic patients (two out of 10 TEM parameters). Individually, pathological TEM parameters were found in seven (41%) cyanotic patients (P=0.003; vs. normal patients) and in three (17%) acyanotic patients (P=0.01). More than one abnormal TEM coagulation parameter was found in four patients, all of them cyanotic patients. Hyperfibrinolysis was detected in one patient, a cyanotic patient. The present investigation confirms previous findings that in patients with CHD the heart defect itself compromises coagulation monitored with TEM, but in addition, we demonstrate that cyanosis and/or polycythemia exert the essential negative impact on hemostasis. Preoperative hyperfibrinolysis detected with TEM seems to play no important role.

Controversies in pregnancy and congenital heart disease

As increasing numbers of children with congenital heart disorders reach adulthood, the family physician, cardiologist, and obstetrician will increasingly be called upon to give advice regarding the safety of pregnancy. This need has been further highlighted by the recognition that maternal mortality associated with cardiac disease is rising. Unfortunately, this field of practice remains relatively "evidence-sparse" with many management decisions being guided by anecdote and "best guess" common sense. Not surprisingly, this results in many fundamental controversies over the optimal care these patients should receive. This article highlights, through the use of case histories, some of these contentious areas, reflecting the different manifestations of congenital maternal cardiac disease and highlighting the limitations of our knowledge.

The Anesthesiologist's Role in Adults with Congenital Heart Disease

Anesthesia for adults with congenital heart disease has many challenging physiologic considerations. Collaborative relationships of a multidisciplinary team including cardiology, cardiac surgery, anesthesiology, and intensive care are essential to ensure positive outcomes in this population for noncardiac and cardiac surgery.

Activated thrombelastogram in neonates and infants with complex congenital heart disease in comparison with healthy children

BACKGROUND

The goal of the study was to determine activated thrombelastographic (TEG(R)) parameters with the rotational TEG(R) (ROTEG or ROTEM) device (Pentapharm GmbH, Munich, Germany) in neonates and infants <1 yr with complex congenital heart disease (CCHD) and to compare them with those of healthy children.

METHODS

A total of 59 children were included: Group I (Gr I) 24 children, ASA I, scheduled for minor surgery; and Group II (Gr II) 35 children with CCHD, ASA III-IV, scheduled for cardiac surgery. Each group was subdivided into four age groups. Blood samples were obtained before the surgical procedure.

RESULTS

Statistically significant differences (two-way anova analysis) between Gr I and Gr II [mean (SD); P-value] were found in INTEG-CT [Gr I 175(19), Gr II 271(162); P=0.049], EXTEG-MCF [Gr I 63(8), Gr II 56(8); P=0.013], EXTEG-MCE [Gr I 186(65), Gr II 137(41); P=0.003], FIBTEG-MCF [Gr I 24(7), Gr II 19(5); P=0.012], FIBTEG-MCE [Gr I 32(13), Gr II 24(8); P=0.012] and EXTEG-MCE-FIBTEG-MCE [Gr I 155(55), Gr II 113(37); P=0.003]. Clotting time via contact activation was prolonged in Gr II and varied widely, mainly in the age group 0-1 month and to a lesser extent in 1-3 months, and maximum clot firmness was reduced in the same age groups. In comparison with Gr II, the healthy children showed relatively homogenous TEG values with a tendency to hypercoagulability; the maximum was found in age group 1-3 months, decreasing towards adult values in the course of the first year of life.

CONCLUSIONS

These preliminary TEG results indicate that the coagulation-fibrinolytic system in CCHD patients <1 yr is functionally intact and balanced but at a lower level than in healthy children. This could be interpreted as a reduction in the haemostatic potential with less reserve.

Effects of hemodilution on outcome after modified Blalock-Taussig shunt operation in children with cyanotic congenital heart disease

OBJECTIVE

Cyanotic congenital heart diseases (CCHD) with secondary polycythemia and hyperviscosity state are associated with a reduction in blood flow, stagnation of blood, and thrombosis. Sufficient hemodilution in cyanotic children results in higher blood flow and significant reductions in perioperative blood loss. The aim of this study was to investigate similar beneficial effects of hemodilution in preventing shunt thrombosis and decreasing postoperative blood loss after modified Blalock-Taussig (BT) shunt operations in children with CCHD.

DESIGN

Prospective, randomized, controlled study.

SETTING

Cardiac center of a tertiary care, referral hospital.

PARTICIPANTS

Fifty children with CCHD undergoing modified BT shunt operations.

INTERVENTIONS

Patients were randomized into 2 groups. The study group (n = 25) received a calculated amount of 6% hydroxyethyl starch (200/0.5) solution to bring down the hematocrit to 45%, whereas the control group (n = 25) received 5% dextrose solution intraoperatively as per the authors' normal protocol.

MEASUREMENTS AND MAIN RESULTS

Effects of hemodilution on shunt patency, postoperative blood loss at 24 hours, blood and blood component usage, and re-exploration rates were recorded. The shunt patency rate was significantly higher in the study group than the control group (100% and 84%, respectively, p < 0.05). Postoperative blood loss at 24 hours was significantly higher in the control group than in the study group (14.4 +/- 11.8 mL/kg and 9.9 +/- 8 mL/kg, respectively, p < 0.05). The number of recipients and the amount of blood and blood components administered were higher in the control group, but they were not statistically significant. The re-exploration rate (for excessive postoperative chest-tube drainage) was significantly higher in the control group than the study group (12% and 0%, respectively, p < 0.05).

CONCLUSION

Hemodilution in CCHD patients undergoing modified BT shunt surgery has beneficial effects including improved shunt patency because of higher blood flow through the graft and less postoperative blood loss, which may be attributed to the lower viscosity produced by hemodilution.

Severe polycythemia in an infant with uncorrected tetralogy of Fallot presenting for noncardiac surgery

Pediatric patients with uncorrected cyanotic congenital heart diseases may present for noncardiac surgery. Associated congenital defects and severe uncompensated secondary erythrocytosis may complicate their anesthetic management. We describe the uncomplicated anesthetic for open G-tube placement of an ex-premature 8-month-old infant with uncorrected tetralogy of Fallot, multiple associated congenital anomalies, and a preoperative hematocrit of 78% and review the anesthetic implications of severe polycythemia.

Cardiopulmonary bypass for adults with congenital heart disease: pitfalls for perfusionists

The fixed incidence of congenital heart defects and improved survival have resulted in increasing numbers of adults with congenital heart disease (CHD) who have undergone complex repairs and/or palliations. Eventually, there will be more adults with CHD than children. They will require cardiac surgical interventions associated with progression of their CHD or for age-related disease, such as coronary revascularization. During bypass, anatomical shunts may exist within or without the heart. Left-to-right shunts can result in dramatically lower systemic blood flow than pump flow due to 'steal', while pulmonary edema ensues due to excessive pulmonary flow. Right-to-left shunts carry risks of massive air embolism and double or triple venous cannulation may be necessary. Cannulation of composite reconstructed aortas may be difficult, risking dissection or aortic obstruction, and double arterial cannulation may be indicated. Aberrant coronary arterial and venous anatomy may .preclude adequate myocardial preservation with common techniques and can be complicated by aortic insufficiency. Valves and conduits may exhibit failure. Conventional monitoring, such as central venous oximetry, may be misleading. Monitoring, such as serial lactate measurement, near-infrared spectroscopy and transcranial Doppler blood velocity, offer advantages for such patients. The perfusionist needs to be aware of such conditions as much congenital aberrancy may present unexpectedly during cardiac surgery.

Low Arterial Saturation Is Associated With Increased Sensitivity to Activated Protein C in Children With Congenital Heart Disease

OBJECTIVES

Children with congenital heart disease experience both hemorrhagic and thrombotic complications. In this report the authors test the hypothesis that hypoxemia is associated with altered sensitivity to activated protein C (aPC) in pediatric patients with congenital heart lesions.

DESIGN

A retrospective genetic registry review, with statistical evaluation of factors contributing to the aPC ratio.

SETTING

Large university hospital.

PARTICIPANTS

Cohort of 92 children with congenital heart disease undergoing cardiac catheterization procedures.

INTERVENTIONS

The authors measured the aPC ratio at cardiac catheterization and evaluated the contribution of independent variables using linear regression and classification tree approaches. Independent variables included age, gender, use of aspirin, history of thrombosis, room air arterial saturation, factor VIII:C levels, presence of congestive heart failure, and heterozygosity for factor V Leiden.

MEASUREMENTS AND MAIN RESULTS

At univariate analysis, factor V Leiden, female gender, room air arterial saturation, age greater than 6 months, and plasma factor VIII:C levels were associated with a lower aPC ratio (resistance to aPC). At stepwise linear regression, arterial saturation, factor VIII:C level, female gender, and factor V Leiden were independently associated with a lower aPC ratio, and these variables explained about 49% of the variability in aPC ratio. The classification tree approach confirmed the dependence of aPC ratio on factor V genotype and arterial saturation.

CONCLUSIONS

The aPC ratio in this population is associated with hypoxemia, independent of factors previously observed in adults. Further studies are under way to determine how aPC resistance or sensitivity may independently affect perioperative hemostasis in this population.

Systemic oxygen saturation and coagulation factor abnormalities before and after the fontan procedure

Coagulation factor abnormalities are believed to predispose to increased risk for thromboembolism after the Fontan procedure. Recent data, however, suggest that coagulation abnormalities may precede the operation. This study determined coagulation factor abnormalities in patients with single-ventricle congenital heart defects before the Fontan procedure and compared the findings with age-matched post-Fontan patients and control subjects. Liver function, coagulation factor levels, and pulse oximetry readings were determined in 11 pre-Fontan patients aged 9.3+/-5.6 years. The results were compared with those of 11 age-matched post-Fontan patients, at 9.1+/-2.4 years after the Fontan procedure, and 11 age-matched controls by simple analysis of variance and post hoc Tukey's test. Liver function was normal in patients before and after surgery apart from mildly elevated bilirubin levels in post-Fontan patients (p=0.027). When compared with controls, pre-Fontan patients had significantly lower levels of protein C; protein S; antithrombin III; and factors II, V, VII, and X and longer prothrombin times (all with p<0.05). When compared with post-Fontan patients, pre-Fontan patients had similarly lower levels of free protein S (p<0.001), protein C (p=0.06), and antithrombin III (p=0.001). Systemic oxygen saturation correlated positively with the levels of anticoagulants (protein C, protein S, antithrombin III) and procoagulants (factors II, V, VII, and X) (all with p<0.05, r=0.33 to 0.61). In conclusion, the findings suggest that coagulation factor abnormalities precede the Fontan procedure and tend to normalize after the operation, relating perhaps to improved systemic oxygenation.

Anesthetic Care During Modified Fontan Procedure Without Cardiopulmonary Bypass

OBJECTIVE

The purpose of this study was to report the anesthetic care of patients during performance of a Fontan procedure without cardiopulmonary bypass (CPB).

DESIGN

Retrospective chart review.

SETTING

Operating room of a university hospital.

PARTICIPANTS

Seven pediatric-patients undergoing inferior vena cava (IVC)-to-pulmonary artery (PA) anastomosis for completion of the Fontan procedure.

INTERVENTIONS

Charts were reviewed for anesthetic technique, hemodynamic and ventilatory changes occurring during the procedure, and anesthetic interventions that were provided.

MEASUREMENTS AND MAIN RESULTS

The off-bypass Fontan procedure was attempted in 7 patients (age: 26 months-7 years, weight: 13 to 28 kg). Exposure of the PA was not feasible in 1 patient because of a markedly enlarged right atrium. In the remaining 6 patients, before cross-clamping of the PA to allow for the proximal anastomosis between the PA and the conduit, alkalosis (pH > or =7.5) was maintained by the administration of sodium bicarbonate. After PA cross-clamping, fluid administration was necessary in 5 patients and dopamine (3-7 microg/kg/min) was necessary in 4 patients. The minute ventilation was increased by 18 +/- 7% to maintain baseline PaCO2 values. Before the placement of the PA cross-clamp, the end-tidal PaCO2 difference was 7 +/- 4 mmHg and the transcutaneous (TC)-PaCO2 difference was 3 +/- 2 mmHg. The end-tidal PaCO2 difference increased to 14 +/- 6 mmHg during cross-clamping of the PA, whereas no change was noted in the TC-PaCO2 difference. Once the proximal anastomosis was completed, a bridge was placed to redirect blood from the IVC to the right atrium while the IVC was clamped and attached to the distal end of the conduit. After placement of the distal end of the bridge into the IVC, fluid administration to maintain the blood pressure was necessary in 3 patients. In 1 patient, 20 minutes after placement of the bridge, the authors noted a progressive increase in the central venous pressure reading measured from the left femoral vein and the need for the administration of volume to maintain the mean arterial pressure. Examination of the bridge revealed occlusion with thrombus despite an activated coagulation time value of 250 to 300 seconds. The tracheas of 3 of the 6 patients were extubated in the operating room, whereas the other 3 were extubated in the pediatric intensive care unit within 4 hours of completion of the procedure. The 1 patient who required the use of CPB required reintubation and had a protracted intensive care unit course. The other 6 patients were discharged home on postoperative days 7 to 12.

CONCLUSIONS

With alteration of the anesthetic technique, the Fontan procedure can be performed in selected patients without the need for CPB.

Single-ventricle physiology: perioperative implications

Neonates with functional single ventricles have pulmonary and systemic circulations that are supplied in parallel, creating significant cyanosis and ventricular volume overload. The goal of palliative surgery, excluding transplantation, is to convert single-ventricle circulation from a parallel to a series arrangement. This will ultimately require a complete cavopulmonary anastomosis (Fontan-type procedure) in which vena caval blood is rerouted directly into the pulmonary circulation. Various factors require that this palliation occur in stages. Stage I surgery, which is often a Norwood procedure, is done in the neonatal period and stabilizes, but does not resolve, parallel circulation. The tenuous balance between pulmonary and systemic perfusion during this stage makes noncardiac surgery hazardous, and it should be restricted to urgent or emergent indications. Stage II surgery, or partial cavopulmonary anastomosis, relieves both parallel circulation and volume overload, but not cyanosis. Relatively stable hemodynamics during this stage create favorable conditions for elective surgery. Patients who have undergone stage III surgery, the Fontan-type repair, vary in age from toddlers to adults, and in physical status from well-compensated to significantly debilitated. Fontan patients require thorough preoperative assessment when elective surgery is contemplated. Optimal communication between surgeons, anesthesiologists, and cardiologists is essential when caring for the patient with single-ventricle physiology.

Soluble P-selectin and thrombomodulin-protein C-Protein S pathway in cyanotic congenital heart disease with secondary erythrocytosis

INTRODUCTION

The aim of the study was to elucidate the roles of soluble P-selectin and thrombomodulin (TM)-protein C-protein S pathway in the pathogenesis of coagulopathy or thrombosis in cyanotic congenital heart disease (CCHD) with secondary erythrocytosis, and their correlations with hematocrit (Hct) value.

MATERIALS AND METHODS

We studied 27 patients (age: 4.8 to 34.9, median 15) with cyanotic congenital heart disease complicated by secondary erythrocytosis (hematocrit >45%) and 26 patients with acyanotic congenital heart disease (ACHD). Plasma levels of P-selectin, beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), thrombomodulin, protein S and activity of protein C were compared between the two groups, and the relationships between these indices and hematocrit value were evaluated.

RESULTS

Plasma levels of P-selectin, beta-thromboglobulin and platelet factor 4 [mean (S.D.)] were significantly high in cyanotic patients comparing with acyanotic patients [138 (70.1) vs. 82.5 (28.7), p<0.001; 94.4 (74.0) vs. 54.9 (19.7), p<0.01; 45.4 (48.7) vs. 22.7 (11.9), p=0.020, respectively]. Those of thrombomodulin and protein S and activity of protein C were significantly low in cyanotic patients comparing with acyanotic patients [22.1 (9.69) vs. 34.3 (27.4), p=0.029; 90.7 (15.1) vs. 112 (21.4D), p<0.0001; 88.8 (19.7) vs. 106 (27.7), p<0.01, respectively]. P-selectin (r=0.445, p=0.001) and beta-thromboglobulin (r=0.311, p=0.025) correlated positively, and platelet count (r=-0.418, p=0.0015), protein C (r=-0.322, p=0.018) and protein S (r=-0.368, p=0.007) correlated negatively with hematocrit.

CONCLUSIONS

Chronic platelet activation and suppression of the thrombomodulin-protein C-protein S pathway might play an important role in coagulopathies identified in patients with erythrocytosis. Hematocrit is an important determinant of such abnormalities.