The univentricular repair indications, procedures, outcomes and controversiesPresentation Transcript
Karyn P. Luna, M.D.
Updates on the indications, timing and outcome of univentricular repair. Present surgical options. Discuss the controversies regarding the modifications of the Fontan operation.
A heart that lacks two well-developed ventricles: Hypoplastic left heart syndrome Hypoplastic right heart
Tricuspid atresia+/- pulmonary atresia with intact ventricular septum, double inlet left ventricle, double outlet right ventricle, unbalanced atrioventricular septal defects and hypoplastic left heart syndrome.
Generally, the risk to siblings and offspring of affected individuals is 2% to 5% (19% -33% of siblings HLHS) . Clinical manifestations and initial management hinge on the presence or absence of pulmonary and systemic outflow obstruction. Natural history Left ventricle dominant= 70% died before age 16 Right ventricle dominant =50% died before 4 years Fontan operation: 20-year survival rate and freedom from heart transplantation of 80%-82%. Paul Khairy, MD, PhD et al.Circulation. 2008 Staged repair allows progressive adaptation of the heart and lungs and reduces the overall perioperative morbidity and mortality. SandeepNayak,PD Booker MBBS MD FRCA
Create unobstructed systemic outflow, unobstructed systemic and pulmonary venous return Provide balanced pulmonary and systemic circulations. Totally separate the systemic and pulmonary venous return and provides pulmonary blood flow without a ventricular pumping chamber. Effective strategies to preserve pulmonary, ventricular and valvular function. Paul Khairy, MD, PhD et al.Circulation.2007
Balanced circulation: No early intervention The aim of the initial palliation is to provide complete relief of any systemic obstruction, if it exists, and provide pulmonary blood flow just sufficient to allow adequate oxygen delivery to tissues and pulmonary arterial growth. Procedures: Pulmonary Artery banding Modified Blalock-Taussig shunt Modified Norwood 1/Sano repair Hybrid procedure
Setting:Pulmonary overcirculation Pulmonary artery banding : Pulmonary blood flow must be minimized to ensure that PVR is kept low and the ventricle does not have an excessive volume load.
Advantages of mBTS: Improve oxygen saturation Facilitate growth of pulmonary arteriesDisadvantages of mBTS: Ventricular volume overload Increase in pulmonary arterial pressure Distortion of pulmonary arteries
The long-term effects of marked single-ventricle preload and inefficient oxygenation via an arterial shunt rarely allowed survival beyond the second or third decade of life. Welton M. Gersony, MD Circulation 2008
Setting: HLHS Modified Norwood 1 or Sano repair Hybrid procedure First 2 weeks of life Permanent systemic outflow utilising the right ventricle Temporary pulmonary blood supply to allow the pulmonary vasculature to develop and mature. Up to 20-25% mortality rate
U Theilen, L Shekerdemian. Arch Dis Child Fetal Neonatal Ed 2005
Modified Norwood 1 The main pulmonary artery(MPA) is divided Proximal MPA is anastomosed to the ascending aorta Aortic arch is repaired Augmented pulmonary blood flow is maintained via a mBTS
Sano repair: Similar to NW 1 but with RV-PA conduit instead of mBTS. Theoretical advantage of avoidance of aorto-pulmonary runoff, resulting in higher coronary and systemic perfusion pressures and reducing the incidence of ventricular.
Risk factors for midterm mortality were cardiorespiratory failure requiring ventilation and ACS ≥20, but not shunt type. Increased number of shunt-related interventions before the Glenn procedure were noted with Sano. CONCLUSIONS: Preoperative risk factors, regardless of shunt type, influence midterm survival after the Norwood procedure with an excellent outcome in low-risk patients, while high-risk cases still incur a significant mortality. Given the possible negative effects of ventriculotomy on right ventricle function, the widespread use of Sano shunt should be reconsidered. Does the shunt type determine mid-term outcome after Norwood operation? Joachim Photiadisa, et al November 15, 2011.
Setting: HLHS The Hybrid Procedure Interventional ductal stenting & surgical bilateral pulmonary artery banding An alternative to the NW in HLHS for high-risk patients This approach has been extended to borderline left heart structures. David Anderson, Conal Austin, Shakeel Qureshi et al. European Journal of Echocardiography (2010)
Hybrid vs NW: Hybrid has lower 1st stage mortality but higher interstage mortality. Possible causes are closing PFO, short stent, myocardial ischemia. = the 2nd stage is a more difficult operation. Pizarro et al. Eur J CTS. 2008Overall, no difference in outcome at 6 months. Pizarro et al Thorac CVS 2010
The advantage of the BDG/HemiFontan over the Blalock-Taussig shunt is to allow an increase of effective pulmonary blood flow without an increase in total pulmonary blood flow and cardiac work. Davide F. Calvaruso, et al Ann Thorac Surg 2008 An interstage mortality of 10–15% Most interstage deaths are sudden and apparently unpredictable. U Theilen, L Shekerdemian. Arch Dis Child Fetal Neonatal Ed 2005
Setting: Cyanosis or pulmonary overcirculation or balanced CavoPulmonary Connection Bidirectional Glenn Shunt or Hemi-Fontan operation : Duration of 15 months because after surgery, the patient is at risk of developing intrapulmonary arteriovenous shunts SandeepNayak, PD Booker MBBS MD FRCA
Benefits of Cavopulmonaryconnection: Decreased cyanosis Decreased intracardiac volume overloadO MonteinNgodngamthaweesuk et al Asian CardiovascThorac Ann 2007
Procedures Bidirectional Glenn Hemi-FontanCardiopulmonary Bypass +/- +SVC-PA connection + +Transection of SVC + -Repair of TV & PA +/- +
Operative mortality rate of BDG/HemiFontan is 5%-7%Freedom from failure at 10 years was 99.2% for theFontan group and 67.4% for the BDG patients. Jenkins KJ.Eur J Cardiothorac Surg 2010
Modified Fontan operation: Total cavopulmonary connection (TCPC) 18 months – 4 yrs. old (or 6-18 months post-Glenn or hemi- fontan)
ORIGINAL FONTAN MODIFIED FONTAN
LATERAL TUNNEL FONTAN EXTRACARDIAC FONTAN
LATERAL TUNNEL EXTRACARDIAC Intra- atrial baffle from IVC A tube graft from the IVC to SVC to RPA outside the heart.
LATERAL TUNNEL EXTRACARDIAC
Lateral Tunnel ExtracardiacAge/Weight >/= 2 years old >/= 5 years old (13 kg)CPB + +/-Growth potential + -Exercise tolerance Similar SimilarArrhythmia Similar SimilarThrombosis Low risk High riskEffusions Less prolonged ProlongedEarly mortality 2%-5% Similar20-yr. survival 82% Similar
STS Congenital Heart Surgery Database: 2,747 Fontan operations (2000 to 2009) in 68 centers A right-dominant ventricle 45%. Extracardiac conduit Fontan vs lateral tunnel)was performed in 63%; in all, 65% were fenestrated. In multivariable analysis the extracardiac conduit Fontan was associated with significantly higher Fontan takedown/revision and Fontan failure and longer postoperative hospital stay. Conclusions: The lateral atrial tunnel Fontan may be associated with superior early outcomes. Constantine Mavroudis, Marshall L. Jacobs, et al January 3, 2012.
Age above 4 years Normal ventricular function Adequate pulmonary artery size No distortion of pulmonary arteries from prior shunt surgery Low pulmonary artery pressure (below 15 mmHg) Low pulmonary vascular resistance Normal systemic venous drainage No atrioventricular valve leak Normal heart rhythm No right atrial enlargement
Negative prognostic factors for both early and late outcome: Ventricular function Pulmonary artery pressure William J. Brawn.Circulation. 2001
Three groups of PA sizes using the PA index (PAI) Hypoplastic PA (<180 mm2/m2)=impedance increase especially at 100mm2/m2 Relatively small PA (180-250 mm2/m2) Good PA (250mm2/m2) Jae Suk Baek et al. Ann Thorac Surg 2011
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Recent 15-year survival reports post-Fontan: 85% was recently reported by the Boston Children’s Hospital , USA 82 ± 3% recently reported by Birmingham Children’s Hospital, UK Preoperatively impaired ventricular function and elevated pulmonary artery pressures have an adverse influence on both early and late outcome. Long-term viability after the creation of a Fontan circulatory arrangement is most dependent on maintenance of sinus rhythm, the behavior of the pulmonary vasculature, and the performance characteristics of the ventricle Alvin J. Chin et al. World Journal for Pediatric and Congenital Heart Surgery 2010 Riad B.M. Hoseina, William J. Brawn J ThoracCardiovascSurg 2012
A 15 year follow-up on somatic growth after Fontan operation: Body weight and BMI have significantly improved by 1 year after the operation. Height has significantly improved by 2 years postoperatively. Patients with BDG shunts showed significantly better weight and BMI at the time of the Fontan operation compared with those without prior BDG shunts . Fenestration is beneficial suggesting that mild arterial desaturation is well tolerated and permits catch-up growth. The pace of catch-up growth after the Fontan operation is much slower than that after biventricular repair. Masamichi Ono et al. J Thorac Cardiovasc Surg 2007
Oxygen delivery index, at least through their preadolescent years, was normal or near normal to reach a relatively normal height. Alvin J. Chin et al. World Journal for Pediatric and Congenital Heart Surgery 2010
Physical and Psychosocial Summary scores of the Child Health Questionnaire Parent Form were within the normal range for over 80% of patients. Carl Lewis Backer.J. Am. Coll. Cardiol. 2008 Greater differences between parent and child-completed scores for the domains of physical functioning and impact of physical limitations. Children may “adapt” better to their situation and rate the impact of the illness to be better. Recommendation: Clinicians should consider both parent and patient viewpoints when counseling patients. Parent- Versus Child-Reported Functional Health Status After the Fontan Procedure Linda M. Lambert et al. Pediatrics2009
Finding of apparently impaired systolic function in the RV subgroup relative to the LV and mixed subgroups is consistent with the general opinion that the structure of the RV is suboptimal for a systemic ventricle. The tricuspid valve is more likely to fail as a systemic AV valve. Page A. W. Anderson, MD, et al. J Am CollCardiol 2008
Arrhythmia occur in 10-40% of patients regardless of the type of Fontan. Cardiac rhythm is important in this circulation: Loss of atrio-ventricular synchronisation will cause an increase of the pulmonary venous atrial pressure and/or a diminished ventricular preload, Both of which are known to have negative effects on a Fontan circuit. Marc Gewilliga et al. European Association for Cardio-Thoracic Surgery 2010. Ventricular tachycardia was detected 15 years post surgery, especially in older patients with older age at Fontan operation. Yuki Nakamura, MD .J Thorac Cardiovasc Surg 2010
Lymphatic circulation may be affected by high venous pressure and impaired thoracic duct drainage. Increased pulmonary lymphatic pressure may result in interstitial pulmonary edema, lymphedema &/or protein losing enteropathy. Protein losing enteropathy is characterized by excessive loss of proteins from serum into the intestinal lumen with mesenteric vascular inflammation. Manifestations include oedema, immunodeficiency, ascites, malabsorption of fat, hypercoagulopathy, hypocalcaemia, and hypomagnesaemia. SandeepNayak , PD Booker MBBS MD FRCA
During a 10-yr follow-up, PLE incidence is about 13%. Poor prognosis (60% 5-yr and 20% 10-yr survival after diagnosis). Treatment: Diet low in salt and high in calories, protein content, and medium chain triglycerides. Diuretics, corticosteroids, heparin, and octreotide (a somatostatin analogue) Fontan fenestration; Fontan takedown or revision; or cardiac transplantation. SandeepNayak , PD Booker MBBS MD FRCA
Plastic bronchitis : less than 1%–2% of patients. Noninflammatory mucinous casts that form in the tracheobronchial tree and obstruct the airway. Related to the increased enteric loss of alpha-1-antitrypsin Alvin J. Chin et al. World Journal for Pediatric and Congenital Heart Surgery 2010 Clinical manifestations are dyspnea, cough, wheezing, and expectoration of casts, which may cause asphyxia, cardiac arrest, or death. Medical management is difficult; often require repeat bronchoscopy to remove the thick casts. Treatment: Fontan fenestration; Fontan takedown or revision or transplantation. Tyler B. Fredenburg, Mervyn D. Cohen, MBChB .Ann Thorac Surg 2005
Circulating ‘‘hepatic factors,’’ which are responsible for either stimulating a repressor of pulmonary arteriovenous malformations (PAVMs) or repressing an activator of PAVMs. Alvin J. Chin et al. World Journal for Pediatric and Congenital Heart Surgery 2010
The ventricle evolves from being volume overloaded and overstretched, to overgrown and (severely)underloaded. The deprived ventricle in a Fontan circuit shows systolic and diastolic dysfunction. The ventricle may now enter a vicious cycle whereby the low preload results in remodelling, reduced compliance, poor ventricular filling, and eventually continuously declining cardiac output. This phenomenon of progressive ‘‘disuse hypofunction’’ occurs at a chronic preload of less than 70% of the ‘‘due’’ preload. Marc Gewillig. Heart 2005
Freedom from failure at 10 years was 99.2% for theFontan group and 67.4% for the BDG patients. Jenkins KJ.Eur J Cardiothorac Surg 2010The mean age at the time of failure symptoms 17.2 ± 6.3years.The indications for transplantation was protein-losingenteropathy, arrhythmia with ventricular dysfunction ,and heart failure Paolo Ferrazzi. Ann Thorac Surg 2001
Staged vs. Primary Fontan operation (or total cavopulmonary connection) Antenatal diagnosis Age Fenestrated vs. non-fenestrated Fontan Arrhythmia Anticoagulation Cognitive, psychosocial and somatic development Pregnancy
SVC and IVC to PA connections originally were performed at the same time, which in many patients resulted in a marked increase in blood flow to the lungs, pulmonary lymphatic congestion, and prolonged problems due to pleural effusions. Currently, surgeons create total cavopulmonary Fontan circulation in at least two stages to allow the patients body to adapt to the different hemodynamic states and reduce overall surgical morbidity and mortality. Tyler B. Fredenburg,Mervyn D. Cohen, MBChB. Ann Thorac Surg 2005
Better outcome for staged TCPC because of the gradual ventricular unloading and remodelling. An excessive acute volume load reduction gives rise to a fatal afterload mismatch. Cardiovascular deaths and heart transplantation occurred less frequently when the Fontan procedure was performed in patients with a previous bidirectional Glenn/ hemi-Fontan procedure. Doty . Int J Cardiol,2006 Advantages of staging towards Fontan operation are almost universally accepted. Yorikazu Harada et al. Interactive CardioVascular and Thoracic Surgery 2009
One-stage modified Fontan in low-risk patients (n=15): at least 4 years for the lateral tunnel, and older than 6 years for the extracardiac conduit; McGoon ratio > 1.8 or PA index > 200, low PA pressure (< 15 mm Hg), and no AVVR. 2-stage procedure for high-risk patients (n=13). Result: 4 hospital deaths in the 1-stage group (operative mortality, 26.6%) No death occurred in the 2-stage group ( p < 0.05). Three of the 4 deaths were due to elevated CVP, despite preoperative cardiac catheterization demonstrating mean PA pressure < 20 mm Hg. O MonteinNgodngamthaweesuk et al. Asian CardiovascThorac Ann 2007
The 1-stage modified Fontan procedure may put patients at higher surgical risk due to poor cardiovascular adaptation. O MonteinNgodngamthaweesuk et al. Asian CardiovascThorac Ann 2007 An intermediate Glenn shunt and lower postoperative pulmonary artery pressure as significant predictors of better outcome. Nelson Alphonso, David Anderson Presented at the joint 17th Annual Meeting of the European Associationfor Cardio-thoracic Surgery and the 11th Annual Meeting of the EuropeanSociety of Thoracic Surgeons, Vienna, Austria, October 12-15, 2003.
The reported impact of prenatal diagnosis on overall survival is variable Infants diagnosed prenatally are certainly less likely to experience the sequelae of pulmonary overcirculation or acidosis. Prenatal diagnosis is associated with improved neurological outcome and with a lower incidence of preoperative acidosis and ventricular dysfunction, and the need for less inotropic support. U Theilen, L Shekerdemian. Arch Dis Child Fetal Neonatal Ed 2005
< 7 yrs old > 7 yrs oldOperative mortality Similar 5.4%Ventricular dysfunction Late EarlyArrythmia Similar SimilarArteriovenous Rare More frequentmalformation Carlo Pace Napoleone Eur JCardiothorac Surg 2010
All patients see a progressive decline in their exercise capacity, but the decrease in exercise capacity was accelerated if the Fontan surgery was performed in adolescents and adults rather than in children. In a serial angiographic study comparing Fontan surgerybefore and after the age of 3 years, it was demonstrated that the cardiac index was preserved if Fontan surgery took place before 3 years of age, and progressively deteriorated if performed at a later age. Yves d’Udekem, Eur J Cardiothorac Surg 2011
Fifteen patients underwent TCPC completion: extracardiac conduit (n = 13), lateral tunnel (n =1), and direct anastomosis of the inferior vena cava and pulmonary trunk (n = 1) The mean age at operation was 27 +/- 9 years (range, 16-52). The mean follow-up period was 57 +/- 45 months (0 to 154). All patients had at least 2 risk factors (2 to 8). Mean pulmonary artery pressure of 20 mm Hg or higher is their only contraindication to TCPC . Mean PVR of 4.0 wood units, pulmonary arterial index of 150, and ejection fraction of 40% are usually acceptable. Midterm to Long-Term Outcome of TCPC in High-Risk Adult Candidates Shunji Sano, MD, et al . Ann Thorac Surg 2009
Overall mortality rate was 13.3%. Conclusion: To improve quality of life and long-term prognosis, TCPC completion should be performed as soon as possible, and TCPC conversion should be performed at an early stage of the morbidities. : TCPC could be offered to high-risk adult Fontan candidates, with an acceptable mortality rate. Midterm to Long-Term Outcome of TCPC in High-Risk Adult Candidates Shunji Sano, MD, et al . Ann Thorac Surg 2009
Long-standing cyanosis and volume overload to the ventricle are believed to cause progressive ventricular fibrosis by inducing histopathologic changes, which must result in both systolic and diastolic dysfunction. The ventricular EF and cardiac indexes were significantly higher at 5 and 10 years after the Fontan procedure had been completed in younger patients. Earlier elimination of hypoxia allows better growth of respiratory and skeletal muscles, which would subsequently increase the cardiac index and exercise capacity, especially at 5 and 10 years after the Fontan procedure. Shuichi Shiraishi et al
Only 13% to 16% of patients who underwent Fontan at 3 years of age had moderate to severe AV valve regurgitation, versus 23% to 26% who underwent Fontan at 3 years of age (p 0.01) due to prolonged volume overloading in the patients who were older at Fontan. Conclusion: Support current trends toward primary Fontan at an early age. Carl Lewis Backer, MD, FACC . J. Am. Coll. Cardiol. 2008;52;114-116
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Indications: Small pulmonary arteries Borderline CVP 15 mmHg Poor ventricular function (EF <50%) Moderate-to-severe AVVR Adult patients HLHS Advantages: Improve cardiac output Decrease venous pressure (lessen effusions and Protein-losing enteropathy) Disadvantages: Desaturation Paradoxical embolization Strategy of closure: Transcatheter device John W. Brown et al Ann ThoracSurg2010
Indications for fenestration closure Persistent O2 sat’n of <90% Passed the occlusion test: Does not experience a fall in blood pressure or mixed venous saturation , No rise in right atrial pressure >20 mmHg Jenkins KJ.Eur J Cardiothorac Surg 2010
After closure of Fontan fenestration: No change in peak exercise capacity as demonstrated by percent of predicted VO2, percent predicted ventilatory anaerobic threshold, heart rate, or O2 pulse. This is despite a 12% increase in O2 saturation at peak exercise. Finding demonstrates that exercise tolerance in the Fontan patient is limited by peak blood flow in the pulmonary vascular bed, which is passively perfused by systemic venous pressure. Carl Lewis Backer, MD, FACC. J. Am. Coll. Cardiol. 2008;52;114-116
All patients with clinical thromboembolic events were taking warfarin at the time of the event. Warfarin (INR 1.5 - 2.0.) Aspirin: daily antiplatelet therapy for most Fontan patients Welton M. Gersony, MD Circulation 2008 Warfarin + Aspirin in higher risk: RA-PA connection, external conduit, sluggish venous circulation, or low cardiac output, history of thromboembolism. Yves d’Udekem .Eur J Cardiothorac Surg 2007
Most individual patients palliated with the Fontan procedure in the 1970s and 1980s have cognitive outcome and academic function within the normal range, but the performance of the cohort is lower than that of the general population. Jonas RA, et al.Ann Thorac Surg 2011
By 20–28 weeks gestation, myocardial oxygen consumption and heart rate normally increase by 20% and stroke volume by 40% The physiological increase in blood volume result in atrial distension. Left uterine displacement help avoid sudden hypotension Although women can successfully complete pregnancy with a Fontan circulation, the associated physiological haemodynamic changes have a significant influence on their abnormal heart function. SandeepNayak , PD Booker MBBS MD FRCA
Women can successfully complete pregnancy after adequate Fontan palliation without important long- term sequelae, although it is often complicated by clinically significant (non-)cardiac events. I Subfertility or infertility and menstrual disorders were common. W Drenthen et al. Heart 2006 In the absence of Eisenmenger physiology, pregnancy in the context of cyanotic heart disease has been associated with 30% incidence of maternal cardiovascular complications and prematurity. Paul Khairy, MD, PhD. Circulation 2007
Pregnancy is contraindicated in patients with severely reduced pulmonary blood flow or with severe pulmonary vascular disease (Eisenmenger syndrome) or if ventricular function is poor. Cyanosis poses a significant risk to the foetus, with a live birth unlikely (12%) if oxygen saturation is <85%. ESC Guidelines on GUCH 201o. European Heart Journal
Early staged operation: mBTs for diminutive right-sided structures Norwood operation for diminutive left-sided structures Pulmonary artery band for pulmonary overcirculation No procedure in early infancy for balanced circulations. BDG/HemiFontan at 6 months of age Total cavopulmonary connection at >2 yrs old At least on aspirin ACE inhibitor for signs of ventricular dysfunction Aggressive repair of AV valve regurgitation Fenestration of Fontan circuit for high-risk candidates Counselling and close follow-up.
The average 80% twenty-year survival rate of Fontan operation is based on a mix of patients who had their procedures done before the advent of and after the TCPC, hence, the outcome of current surgical trends could be better. The Univentricular repair, however, remains a challenge to the entire perioperative team.
In 1971, Fontan and Baudet described an atriopulmonary anastomosis as definitive palliation for tricuspid atresia. Mortality rates with the classic atrial pulmonary connection approximated 15% to 25%. It was originally thought that the right atrium, a pulsatile chamber, would improve pulmonary blood flow. However, in a series of experiments by de Leval et al , it was discovered that the right atrium dilated and then lost contractile function, which resulted in turbulence and energy loss and actually decreased pulmonary blood flow Right Atrium with Classic Fontan Circulation Patients with atriopulmonary Fontan circulation are predisposed to development of complications. The right atrium is exposed to elevated systemic and right atrial pressure, which leads to right atrial dilatation and hypertrophy (Fig 11). Dilatation may be severe, and it may lead to complications such as arrhythmia and swirling of blood in the enlarged atrium, which causes stasis and results in poor blood flow to the lungs. Dilatation also may be a predisposing factor for clot formation.Secondary dilatation of the coronary sinus also is seen. Total cavopulmonary connections have the advantage of saving energy compared with the original RA-PA connections,eliminating less effective blood flow via a large, turbulent atrium that sends blood directly to the pulmonary artery. Welton M. Gersony, MD Circulation 2008
In 1988, de Leval and colleagues proposed total cavopulmonary connection by a lateral tunnel as an alternative to the Fontan-type operation with hemodynamic advantagesand reduced atrial complications.1990 when Marcelletti and colleagues described total cavopulmonary connection using anextracardiac conduit from the inferior vena cava to the PA. This has beneficial hemodynamiceffects on systemic venous flow, while the entire atrium is left at low pressure with minimalatrial sutures.
CXR: assess lung disease ECG: rhythm Echocardiography: systemic valvular status, ventricular function, central pulmonary arterial anatomy ,PAP, SVC and IVC anatomy MRI: pulmonary arterial anatomy and flows, collateral circulation, other data to confirm echocardiographic questions Cardiac cath: pulmonary arterial anatomy, PVR
Although echocardiography is widely used in patients with single-ventricle physiology, its ability to comprehensively image all the relevant anatomy, particularly the thoracic vasculature, may be limited in some patients. Four patients in the catheterization group (10%) had findings that were not appreciated at the initial procedure, including a large systemic venovenous collateral vessel, a diffusely small left pulmonary artery requiring intraoperative arterioplasty, a RV aneurysm at a shunt insertion site, and an abscess around a Blalock-Taussig shunt. No new intraoperative or postop. findings in the CMR group. In the absence of evidence of pulmonary hypertension, routine measurement of PVR is not necessary before BDG. Pedro J. del Nido, MD et alCirculation. 2007
Age The Fontan operation in adults has acceptable early and late mortality. Functional class, systolic ventricular function, atrioventricular regurgitation, and arrhythmia deteriorate late after surgery but to a lesser degree than in non-Fontan patients with a single ventricle. Veldtman et al. Heart 2001
All patients with a Fontan circulation have anabnormal cardiorespiratory response to exercise. They have a blunted heart rate response, and Limited ability to increase stroke volume withexercise, due to impaired ventricular function anddifficulty in increasing ventricular preload. SandeepNayak, PD Booker MBBS MD FRCA
Functional health status: Over 80% of subjects scored in the normal range on the CHQ. Parents perceived their children as having lower physical and psychosocial functional status. The lower Physical Summary scores are similar to those for children who have undergone thoracic organ transplantation or cardioverter defibrillator implantation Exercise performance. Maximal exercise performance was lower than normal and worse in older subjects due to: absence of a subpulmonary pumping chamber, abnormal endothelial cell function, increased PVR and SVR, decreased muscle mass, & deconditioning Page A. W. Anderson, MD, et al. J Am CollCardiol 2008
Augment Preload: Increase systemic venous return: Low intrathoracic pressure (low respiratory rates, short inspiratory times, low PEEP, and tidal volumes of 5–6 ml kg, normocarbia, and a low PVR). Normovolemia Decrease afterload: Vasodilators Hyperventilation tends to impair pulmonary blood flow, despite the induced respiratory alkalosis, because of the increased mean intrathoracic pressure. SandeepNayak,PD Booker MBBS MD FRCA
Arrhythmia incidence is similar between EC & LT due to: Right atrial dilatation Sinus node dysfunction High risk to develop arrhythmia: ventricular dysfunction, bilateral superior venae cavae, and heterotaxy syndrome Management: Surgical Maze operation Catheter ablation
Due to the absence of pulsatile blood flow and underfilling of the pulmonary vascular bed, patients with Fontan circulation are at increased risk for formation of pulmonary arteriovenous malformations. Tyler B. Fredenburg, MD, Mervyn D. Cohen, MBChB . Ann Thorac Surg 2005 Effect of residual shunts: volume overload on the ventricle and may induce an irreversible increase in PVR secondary to high regional pulmonary blood flow. Sources of shunts: Fenestration, drainage of coronary sinus aorta-pulmonary collaterals & incomplete occlusion of previous artificial shunts. SandeepNayak , PD Booker MBBS MD FRCA
Typically, cardiac output in a Fontan circulation at rest is decreased to 70% (range 50–80%) of normal for body surface area. Preload to the ventricle is determined by transpulmonary flow (PVR) and a fenestration if present. Since the 1990s when excessive volume overloading and acute unloading have been avoided, ventricular dysfunction has become a less important risk factor. A decrease of afterload without preload reserve will not result in increase of output, but may cause hypotension. Excessive afterload on the other hand may be detrimental,especially in the systemic RV. Marc Gewilliga, European Association for Cardio-Thoracic Surgery. 2010.
Decreasing age, as well as intervals, in staged Fontan palliation have beneficial influence on major complications and outcome. K Francois, M Tamim, T Bove, PediatrCardiol, July 1, 2005. Subjects who were older at time of Fontan had worse AV valve function and decreased likelihood of being in sinus rhythm. Poorer valve function and a decrease in sinus rhythm might be related to a longer period of volume overloading . Recommendation: To complete the Fontan at an earlier age. Page A. W. Anderson, MD, et al. J Am CollCardiol 2008
Indications to leave a pulmonary antegrade flow: Low pre-BDG PA pressure Borderline sizes of the native Pas Definitive palliation for high risk patients for Fontan. Davide F. Calvaruso, et al Ann Thorac Surg 2008 Those without APBF did not enjoy the same degree of PA growth as those with APBF. These differences did not correlate with appreciable differences in clinical outcome after BDG or Fontan.
Advantages : Hepatic flow & pulsatile hemodynamics are maintained that may decrease the tendency for collaterals/AVMs Preserves the ability to catheterize the pulmonary arteries from the femoral veins. Disadvantages : Excessive pulmonary flow Elevated pressures resulting in persistent effusions Brian E. Kogon et al. The incidence of clinical superior vena caval syndrome did not differ between groups with or without antegrade flow. Robert G. Gray, et al. Ann ThoracSurg 2007
Kawashima procedure results in a ‘near complete’ Fontan circulation The Spo2 early after post- Kawashima Fontan was not as high as after control Fontan in most cases, but often improved throughout the postoperative follow-up. Shelby Kutty MD, James S. Tweddell, MD Ann ThoracSurg 2010
Early redirection of hepatic flow after the Kawashima procedure may actually decrease or result in resolution of PAVMs. The resolution of hypoxemia after incorporation of the hepatic veins into the cavopulmonary circuit is likely due to a combination of PAVM resolution and elimination of hepatic venoatrial right-to-left shunting. Extracardiac or lateral tunnel connection are the most common methods for completion Fontan Comparative survival rates after Fontan procedure in heterotaxy and nonheterotaxy patients have been similar. Shelby Kutty MD, James S. Tweddell, MD Ann ThoracSurg 2010