Neither age at repair nor previous palliation affects outcome in tetralogy of Fallot repair.

OBJECTIVES: The study aimed to evaluate the results following complete repair of tetralogy of Fallot (TOF) in relation to age at surgery and to assess the role of palliation in the current era. METHODS: A retrospective review of 251 consecutive patients with TOF repaired between 2003 and 2011 at the Great Ormond Street Hospital was performed. Children were divided into two groups: Group A, younger than 6 months (n = 78) and B, older than 6 months (n = 173). Early clinical outcomes and reoperation/reintervention rates were studied as well as indication for a palliation. RESULTS: There was 1 (0.4%) early and 1 (0.4%) late death after a median follow-up time of 4.5 years. Forty-three patients (17%) underwent repair after initial palliation with inter-stage mortality of 5%. Groups A and B were similar in terms of surgical approach, postoperative complications and length of stay. Significant differences were found in terms of more frequent use of a transannular patch (P = 0.05), longer surgeries (P = 0.02) and a greater proportion of palliated patients (P = 0.002) in older patients. There was no difference in rates of reoperation/reintervention between groups and following both primary and staged repair. Palliated patients were more symptomatic (duct-dependent pulmonary blood flow; P < 0.01, cyanotic spells; P < 0.01), had more extracardiac/genetic anomalies (P < 0.01), coronary anomalies (P = 0.015) and significantly smaller pulmonary annulus, right pulmonary artery (RPA) and left pulmonary artery (LPA) Z-scores (P < 0.01 for all). CONCLUSION: Age at complete repair was not linked to early clinical outcome or reoperation/reintervention rate. Palliative procedures postponed the timing of complete repair, but did not increase the reintervention rate.

Rapid 2-stage Norwood I for high-risk hypoplastic left heart syndrome and variants.

OBJECTIVES: Preoperative comorbidities (PCMs) are known risk factors for Norwood stage I (NW1). We tested the hypothesis that short-term bilateral pulmonary arterial banding (bPAB) before NW1 could improve the prognosis of these high-risk patients. METHODS: From January 2006 to October 2011, 17 high-risk patients with hypoplastic left heart syndrome (defined as having ≥4 of the following PCMs: prolonged mechanical ventilation; older age; sepsis; necrotizing enterocolitis; hepatic, renal, or heart failure; coagulopathy; pulmonary edema; high inotropic requirements; anasarca; weight <2.5 kg; and cardiac arrest) were identified. In addition to conventional treatment of PCMs, they underwent bPAB before NW1. bPAB was undertaken with Silastic slings and secured with ligaclips to a luminal diameter of approximately 3.5 to 4.0 mm. The patency of the ductus arteriosus was maintained with prostaglandin. NW1 was performed using a modified, right Blalock-Taussig shunt at a median interval of 8 days after bPAB. The data from these patients were retrospectively reviewed, and the 30-day mortality and 1-year survival were compared with the hypoplastic left heart syndrome population who underwent primary NW1 with <3 PCMs in the same period. RESULTS: Of the bPAB patients, 5 (29.4%) died before NW1. All had ≥5 PCMs. Twelve patients (70.6%) survived to undergo NW1. One early death occurred after NW1 (8.3%). The 1-year survival rate for high-risk patients who underwent NW1 was 66.7%. The early mortality and 1-year survival for the 130 patients with <3 PCMs was 10% and 80%, respectively. CONCLUSIONS: Optimizing the balance between the pulmonary and systemic blood flow with a short period of bPAB and ductal patency can improve the perioperative conditions of high-risk patients before NW1. Those who survived bPAB and underwent NW1 had early mortality and 1-year survival comparable to the standard risk category, despite the severity of their initial condition. A rapid 2-stage NW1 strategy with bPAB and prostaglandin to maintain ductal patency can avoid the risks of suboptimal palliation and vascular injuries associated with hybrid procedures.

Reduced ascending aorta distensibility relates to adverse ventricular mechanics in patients with hypoplastic left heart syndrome: noninvasive study using wave intensity analysis.

OBJECTIVE: To evaluate the aortic arch elastic properties and ventriculoarterial coupling efficiency in patients with single ventricle physiology, with and without a surgically reconstructed arch. METHODS: We studied 21 children with single ventricle physiology after bidirectional superior cavopulmonary surgery: 10 with hypoplastic left heart syndrome, who underwent surgical arch reconstruction, and 11 with other types of single ventricle physiology but without arch reconstruction. All children underwent pre-Fontan magnetic resonance imaging. No patient exhibited aortic recoarctation. Data on aortic wave speed, aortic distensibility and wave intensity profiles were all extracted from the magnetic resonance imaging studies using an in-house-written plug-in for the Digital Imaging and Communications in Medicine viewer OsiriX. RESULTS: Children with hypoplastic left heart syndrome had significantly greater wave speed (P = .002), and both stiffer (P = .004) and larger (P < .0001) ascending aortas than the patients with a nonreconstructed arch. Aortic distensibility was not influenced by ventricular stroke volume but depended on a combination of increased aortic diameter and abnormal wall mechanical properties. Those with hypoplastic left heart syndrome had a lower peak wave intensity and reduced energy carried by the forward compression and the forward expansion waves, even after correction for stroke volume, suggesting an abnormal systolic and diastolic function. Lower wave energy was associated with an increased aortic diameter. CONCLUSIONS: Using a novel, noninvasive technique based on image analysis, we have demonstrated that aortic arch reconstruction in children with hypoplastic left heart syndrome is associated with reduced aortic distensibility and unfavorable ventricular-vascular coupling compared with those with single ventricle physiology without aortic arch reconstruction.

Midterm follow-up of arterial switch operation for transposition of the great arteries with intact ventricular septum and left-ventricular outflow tract obstruction.

OBJECTIVE: We report the mid-term follow-up of patients, who underwent arterial switch operation (ASO) for transposition of the great arteries (TGA) with intact ventricular septum and left-ventricular outflow tract obstruction (LVOTO) over a 10-year period from 2000 to 2009. METHODS: Thirteen TGA patients (3.9% of our ASO cohort) with intact ventricular septum and LVOTO underwent ASO. LVOTO was defined as pulmonary valve z-score ≤ -2.0 (n=3) or peak LVOT gradient ≥40 mmHg with (n=7) or without (n=3) anatomic subvalvar stenosis on echocardiography. Median age and weight were 14 days (range, 7-130 days) and 3.2 kg (range, 2.1-4.6 kg). The LVOT abnormalities included fibromuscular narrowing (n=5) and atrioventricular valve-related findings (n=5). LVOT clearance was achieved by resection of accessory mitral tissue (n=2) only. RESULTS: Follow-up was 100% complete. There were no early or late deaths. Freedom from re-operation for neo-aortic valve regurgitation and/or LVOTO was 100% at a median follow-up of 38 months (range, 6-115 months). All patients had functional status appropriate for their age. Three patients had mild aortic regurgitation. The median Doppler estimated LVOT systolic gradient was 12 mmHg (range, 0-18 mmHg) for the entire cohort at the latest follow-up. CONCLUSIONS: Mid-term outcomes of ASO for a highly selected group of patients with pulmonary valve annulus z-score ≤ -2.0 ≥ -0.4, resectable organic LVOTO, and dynamic peak LVOT gradient ≥40 mmHg remain satisfactory, with a need for long-term follow-up.

Four decades of Fontan palliation.

The Fontan palliation was introduced in 1968 to treat cardiac malformations unsuitable for biventricular repair. This procedure has transformed the surgical management of congenital heart disease. In this Review, we reflect on the outcomes and clinical problems associated with this unique circulation after more than 40 years of experience. We also summarize the evolution of the Fontan procedure, highlight the long-term clinical issues and their management, and consider future expectations of a circulation driven by a single ventricle with the systemic and pulmonary blood flow in series rather than in parallel.

Evolution of the Fontan-Kreutzer procedure.

The surgical techniques used to construct the Fontan-Kreutzer circulation have evolved considerably since the initial reports. In the early years, it was thought that a power source other than the main ventricular chamber was useful or even necessary to serve the pulmonary circulation. Better understanding of the physiology of the Fontan-Kreutzer circulation has led to an understanding that avoidance of flow disturbances and energy losses in the surgically constructed pathways is critically important. In vitro studies and clinical investigations of flow dynamics led to the introduction of the total cavopulmonary connection, or total cavopulmonary connections, designed to minimize flow disturbances and the resultant energy losses. Other important surgical modifications include staging with a superior cavopulmonary connection and creation of a fenestration. These innovations have resulted in extension of the Fontan-Kreutzer procedure to the management of complex univentricular hearts and, in particular, the management of hypoplastic left heart syndrome. There have been significant improvements of early mortality and morbidity following the Fontan-Kreutzer procedure. Yet it is important to recognize that there is continuing late attrition and morbidity for patients with the Fontan-Kreutzer circulation.

Management of a stenotic right ventricle-pulmonary artery shunt early after the Norwood procedure.

BACKGROUND: Inadequate pulmonary blood flow through a right ventricle-to-pulmonary artery (RV-PA) shunt early after the Norwood operation can be remedied by adding a modified Blalock-Taussig (mBT) shunt. We used multiscale computational modeling to determine whether the stenotic RV-PA shunt should be left in situ or removed. METHODS: Models of the Norwood circulation were constructed with (1) a 5-mm RV-PA shunt, (2) a RV-PA shunt with 3- or 2-mm stenosis at the RV anastomosis, (3) a stenotic RV-PA shunt plus a 3.0- or 3.5-mm mBT shunt, or (4) a 3.5-mm mBT shunt. A hydraulic network that mathematically describes an entire circulatory system with pre-stage 2 hemodynamics was used to predict local dynamics within the Norwood circulation. Global variables including total cardiac output, mixed venous oxygen saturation, stroke work, and systemic oxygen delivery can be computed. RESULTS: Proximal stenosis of the RV-PA shunt results in decreased pulmonary blood flow, total cardiac output, mixed venous saturation, and oxygen delivery. Addition of a 3.0- or 3.5-mm mBT shunt leads to pulmonary overcirculation, lowers systemic oxygen delivery, and decreases coronary perfusion pressure. Diastolic runoff through the stenotic RV-PA shunt dramatically increases retrograde flow into the single ventricle. Removal of the stenotic RV-PA shunt balances systemic and pulmonary blood flow, eliminates regurgitant flow into the single ventricle, and improves systemic oxygen delivery. CONCLUSIONS: Adding a mBT shunt to remedy a stenotic RV-PA shunt early after a Norwood operation can lead to pulmonary overcirculation and may decrease systemic oxygen delivery. The stenotic RV-PA shunt should be taken down. Conversion to an optimal mBT shunt is preferable to augmenting a stenotic RV-PA shunt with a smaller mBT shunt.

Effective transcatheter valve implantation after pulmonary homograft failure: a new perspective on the Ross operation.

OBJECTIVE: The Ross procedure offers good autograft function and low reoperation rates for the neoaortic valve; however, the rate of conduit dysfunction in the right ventricular outflow tract remains a concern. This study assessed percutaneous pulmonary valve implantation in this setting. METHODS: We retrospectively analyzed outcomes of 12 patients (mean age 28 +/- 5 years) referred for percutaneous pulmonary valve implantation to treat right ventricle-pulmonary artery conduit failure 11.1 +/- 3.3 years after Ross procedure. RESULTS: Percutaneous pulmonary valve implantation was feasible in all 12 patients, with no procedural complications (procedure time 99 +/- 16 minutes, fluoroscopy time 21 +/- 6 minutes). Right ventricular outflow tract gradient during catheterization and pulmonary regurgitant fraction on magnetic resonance imaging fell after valve implantation (gradient 34 +/- 6 to 14 +/- 3 mm Hg, P < .01, regurgitant fraction 20% +/- 6% to 2% +/- 1%, P < .05). After restoration of right ventricular outflow tract function, indexed right ventricular end-diastolic volume decreased (91 +/- 13 to 78 +/- 12 mL x beat(-1) x m(-2), P < .01) and maximal cardiopulmonary exercise performance improved (peak oxygen consumption 25.4 +/- 2.3 to 30.8 +/- 3.0 mL x kg(-1) x min(-1), P < .01). During follow-up (18.8 +/- 4.6 months), there was 1 device explantation (restenosis). The probabilities of freedom from right ventricular outflow tract reoperation were 100% at 1 year and 90% at 3 years. CONCLUSIONS: Percutaneous pulmonary valve implantation provides an effective transcatheter treatment strategy to prolong the lifespan of right ventricle-pulmonary artery conduits after the Ross procedure, reducing the reoperation burden on patients with aortic valve disease.

Monitoring risk-adjusted outcomes in congenital heart surgery: does the appropriateness of a risk model change with time?

BACKGROUND: Risk adjustment of outcomes in pediatric congenital heart surgery is challenging due to the great diversity in diagnoses and procedures. We have previously shown that variable life-adjusted display (VLAD) charts provide an effective graphic display of risk-adjusted outcomes in this specialty. A question arises as to whether the risk model used remains appropriate over time. METHODS: We used a recently developed graphic technique to evaluate the performance of an existing risk model among those patients at a single center during 2000 to 2003 originally used in model development. We then compared the distribution of predicted risk among these patients with that among patients in 2004 to 2006. Finally, we constructed a VLAD chart of risk-adjusted outcomes for the latter period. RESULTS: Among 1083 patients between April 2000 and March 2003, the risk model performed well at predicted risks above 3%, underestimated mortality at 2% to 3% predicted risk, and overestimated mortality below 2% predicted risk. There was little difference in the distribution of predicted risk among these patients and among 903 patients between June 2004 and October 2006. Outcomes for the more recent period were appreciably better than those expected according to the risk model. This finding cannot be explained by any apparent bias in the risk model combined with changes in case-mix. CONCLUSIONS: Risk models can, and hopefully do, become out of date. There is scope for complacency in the risk-adjusted audit if the risk model used is not regularly recalibrated to reflect changing standards and expectations.

Use of mathematic modeling to compare and predict hemodynamic effects of the modified Blalock-Taussig and right ventricle-pulmonary artery shunts for hypoplastic left heart syndrome.

OBJECTIVE: Stage one reconstruction (Norwood operation) for hypoplastic left heart syndrome can be performed with either a modified Blalock-Taussig shunt or a right ventricle-pulmonary artery shunt. Both methods have certain inherent characteristics. It is postulated that mathematic modeling could help elucidate these differences. METHODS: Three-dimensional computer models of the Blalock-Taussig shunt and right ventricle-pulmonary artery shunt modifications of the Norwood operation were developed by using the finite volume method. Conduits of 3, 3.5, and 4 mm were used in the Blalock-Taussig shunt model, whereas conduits of 4, 5, and 6 mm were used in the right ventricle-pulmonary artery shunt model. The hydraulic nets (lumped resistances, compliances, inertances, and elastances) were identical in the 2 models. A multiscale approach was adopted to couple the 3-dimensional models with the circulation net. Computer simulations were compared with postoperative catheterization data. RESULTS: Good correlation was found between predicted and observed data. For the right ventricle-pulmonary artery shunt modification, there was higher aortic diastolic pressure, decreased pulmonary artery pressure, lower Qp/Qs ratio, and higher coronary perfusion pressure. Mathematic modeling predicted minimal regurgitant flow in the right ventricle-pulmonary artery shunt model, which correlated with postoperative Doppler measurements. The right ventricle-pulmonary artery shunt demonstrated lower stroke work and a higher mechanical efficiency (stroke work/total mechanical energy). CONCLUSIONS: The close correlation between predicted and observed data supports the use of mathematic modeling in the design and assessment of surgical procedures. The potentially damaging effects of a systemic ventriculotomy in the right ventricle-pulmonary artery shunt modification of the Norwood operation have not been analyzed.

Rescue surgery following percutaneous pulmonary valve implantation.

OBJECTIVE: Percutaneous pulmonary valve insertion (PPVI) is an evolving alternative to surgical pulmonary valve insertion. The aim of this study is to review the acute complications of PPVI requiring emergency rescue surgery. PATIENTS AND METHODS: Between 09/2000 and 01/2007, 152 patients (pts), received a PPVI. Patient's charts were reviewed in retrospect. RESULTS: Emergency rescue surgery (ERS) took place in 6 pts (3.9%). Indications for ERS were: homograft rupture two pts, dislodgment of the stented valve in a dilated right ventricular outflow tract two pts, occlusion of the right pulmonary artery one pt and compression of the left main coronary artery one pt. Cardiopulmonary bypass was established through repeat sternotomy incision with femorofemoral cannulation in 2/6 pts. The stented valve was removed in five and replaced with a homograft in three and a valved conduit in two pts. One ruptured homograft was repaired leaving the stented valve in situ. All patients survived, one sustained mild neurological impairment. CONCLUSION: Although some of the acute complications of PPVI were probably related to a learning curve (4 among the first 50 pts and 2 among the last 102 patients) the need for ERS is unlikely to be completely abolished. This experience highlights the importance of close collaboration between cardiologists and surgeons in these evolving technologies. Highly skilled and responsive surgical back up is necessary to support the introduction and to sustain institutional programmes such as PPVI.

Subdiaphragmatic venous hemodynamics in patients with biventricular and Fontan circulation after diaphragm plication.

OBJECTIVE: Diaphragm paralysis owing to phrenic nerve injury can result in significant morbidity in children undergoing surgical management of congenital cardiac defects. Diaphragm plication is the accepted therapy for diaphragm paralysis. We have investigated subdiaphragmatic venous hemodynamics in patients with biventricular and Fontan circulation after diaphragm plication. METHODS: Doppler ultrasound was used to evaluate flows in the hepatic vein, portal vein, and subhepatic inferior vena cava under respiratory monitoring and with a tilt table. Twenty-nine patients with biventricular circulation were studied: 19 with normal diaphragms and 10 after diaphragm plication. Twenty-eight patients with total cavopulmonary connections after the Fontan procedure were also studied: 19 with normal diaphragms and 9 with plicated diaphragms. Inspiratory/expiratory flow ratios in supine and upright positions were calculated to investigate respiratory effects, and upright/supine flow ratios were calculated to assess gravity effects. RESULTS: In patients with biventricular circulation and normal diaphragms, hepatic venous flow was augmented by inspiration; this effect was reduced in patients with a plicated diaphragm (upright inspiratory/expiratory flow ratios: 2.4 vs 1.4, respectively; P = .01). Portal venous flow was higher during expiration; this effect was lost in patients with a plicated diaphragm (supine inspiratory/expiratory flow ratios: 0.8 and 1.0; P < .05). In Fontan patients with normal diaphragms, hepatic venous flow depended heavily on inspiration. This effect was blunted in patients with a plicated diaphragm (supine inspiratory/expiratory flow ratios: 3.2 vs 2.3; P < .05). Expiratory augmentation of portal flow was absent in Fontan patients with normal diaphragms and reversed in patients a plicated diaphragm (supine inspiratory/expiratory flow ratios: 1.0 vs 1.6; P = .02). Gravity reduced Fontan portal venous flow; having a plicated diaphragm did not alter this effect (upright/supine flow ratios: 0.7 vs 0.7). CONCLUSIONS: In patients with biventricular and those with Fontan circulation with a paralyzed diaphragm, plication does not completely restore normal subdiaphragmatic venous hemodynamics. In Fontan patients with a plicated diaphragm, important inspiration-derived hepatic venous flow is suppressed, and portal venous flow loses its normal expiratory augmentation. These flow dynamics share similarities with those observed in patients with failing Fontan circulation. This suboptimal splanchnic circulation may contribute to early problems of prolonged pleural effusions and ascites and potentially may promote late Fontan failure. Phrenic nerve injury should consequently be avoided at all costs before or at the time of the Fontan operation.

Improving patient safety by identifying latent failures in successful operations.

BACKGROUND: The risk of technical failure during operations is recognized, but there is evidence that further improvements in safety depend on systems factors, in particular, effective team skills. The hypotheses that small problems can escalate to more serious situations and that effective teamwork can prevent the development of serious situations, were examined to develop a method to assess these skills and to provide evidence for improvements in training and systems. METHOD(S): Observations were made during 24 pediatric cardiac and 18 orthopedic operations. Operations were classified by accepted indicators of risk and the observations used to generate indicators of performance. Negative events were recorded and organized into 3 levels of clinical importance (minor problems, those negative events that were seemingly innocuous; intraoperative performance, the proportion of key operating tasks that were disrupted; and major problems, events that compromised directly the safety of the patient or the quality of the treatment). The ability of the team to work together safely was classified using a validated scale adapted from research in aviation. Operative duration was also recorded. RESULT(S): Both escalation and teamwork hypotheses were supported. Multiple linear regression suggests that for every 3 minor problems above the 9.9 expected per operation (P <.001), intraoperative performance reduces by 1% (P = .005), and operative duration increases by 10 minutes (P = .032). Effective teams have fewer minor problems per operation (P = .035) and consequently higher intraoperative performance and shorter operating times. Operative risk affected intraoperative performance (P = .004) and duration (P <.001), with the type of operation affecting only duration (P <.001). Eight major problems were observed; these showed a strong association with risk, intraoperative performance, teamwork, and the number of minor problems. CONCLUSION(S): Structured observation of effective teamwork in the operating room can identify substantive deficiencies in the system, even in otherwise successful operations. Decreasing the number of minor problems can lead to a smoother, safer, and shorter operation. Effective teamwork can help decrease the number of small problems and prevent them from escalating to more serious situations. The most effective and sustainable route to improved safety is in capturing these minor problems and identifying related system improvements, combined with training in safe team working. This method is a validated and practical way to improve performance during otherwise successful operations.

Patient handover from surgery to intensive care: using Formula 1 pit-stop and aviation models to improve safety and quality.

BACKGROUND: We aimed to improve the quality and safety of handover of patients from surgery to intensive care using the analogy of a Formula 1 pit stop and expertise from aviation. METHODS: A prospective intervention study measured the change in performance before and after the implementation of a new handover protocol that was developed through detailed discussions with a Formula 1 racing team and aviation training captains. Fifty (23 before and 27 after) postsurgery patient handovers were observed. Technical errors and information omissions were measured using checklists, and teamwork was scored using a Likert scale. Duration of the handover was also measured. RESULTS: The mean number of technical errors was reduced from 5.42 (95% CI +/-1.24) to 3.15 (95% CI +/-0.71), the mean number of information handover omissions was reduced from 2.09 (95% CI +/-1.14) to 1.07 (95% CI +/-0.55), and duration of handover was reduced from 10.8 min (95% CI +/-1.6) to 9.4 min (95% CI +/-1.29). Nine out of twenty-three (39%) precondition patients had more than one error in both technical and information handover prior to the new protocol, compared with three out of twnety-seven (11.5%) with the new handover. Regression analysis showed that the number of technical errors were significantly reduced with the new handover (t = -3.63, P < 0.001), and an interaction suggested that teamwork (t = 3.04, P = 0.004) had a different effect with the new handover protocol. CONCLUSIONS: The introduction of the new handover protocol lead to improvements in all aspects of the handover. Expertise from other industries can be extrapolated to improve patient safety, and in particular, areas of medicine involving the handover of patients or information.

Surgical approaches for single ventricle palliation.

In this document, we include under the heading of univentricular heart, complex cardiac malformations which have in common the presence of a functionally single ventricle. The evolution of the surgical management of univentricular hearts is discussed along with the indications, selection criteria, and operative approaches for staged palliation. Herein, we describe our technique for bidirectional cavopulmonary anastomosis and total cavopulmonary connection using an extracardiac conduit.

Is complete heart block after surgical closure of ventricular septum defects still an issue?

BACKGROUND: A serious complication after surgical closure of ventricular septal defect (VSD) is complete heart block. In this retrospective study, we reviewed the incidence of complete heart block after surgical closure of a VSD at Great Ormond Street Hospital from 1976 to 2001 to identify any particular anatomic features that still predisposed patients to surgically-induced complete heart block and to provide anatomic guidelines to avoid this in future. METHODS: Data were extracted from our local database for patients having (1) isolated VSD or VSD in the setting of (2) tetralogy of Fallot with pulmonary stenosis or (3) tetralogy of Fallot with pulmonary atresia; (4) absent pulmonary valve syndrome; (5 and 6) coarctation or interruption of the aortic arch; and (7) subaortic fibrous shelf. We carefully reviewed the operative notes from all patients with postoperative complete heart block to discover any predisposing anatomical reasons to explain the complication. RESULTS: Two thousand seventy-nine patients had a VSD closure. Permanent complete heart block developed in 7 of 996 patients (0.7%) with an isolated defect and in 1 of 847 patients (0.1%) with tetralogy of Fallot. Four more patients had postoperative complete heart block. CONCLUSIONS: Instances of iatrogenic complete heart block continue to occur after surgical VSD closure, either because of unexpected biological variations or because of unawareness of the disposition of the atrioventricular conduction axis in particular circumstances. This report emphasizes the latter aspect in details and suggests a risk of iatrogenic complete heart block of less than 1%.

Does the Aristotle Score predict outcome in congenital heart surgery?

OBJECTIVE: The Aristotle Score has been proposed as a measure of 'complexity' in congenital heart surgery, and a tool for comparing performance amongst different centres. To date, however, it remains unvalidated. We examined whether the Basic Aristotle Score was a useful predictor of mortality following open-heart surgery, and compared it to the Risk Adjustment in Congenital Heart Surgery (RACHS-1) system. We also examined the ability of the Aristotle Score to measure performance. METHODS: The Basic Aristotle Score and RACHS-1 risk categories were assigned retrospectively to 1085 operations involving cardiopulmonary bypass in children less than 18 years of age. Multiple logistic regression analysis was used to determine the significance of the Aristotle Score and RACHS-1 category as independent predictors of in-hospital mortality. Operative performance was calculated using the Aristotle equation: performance = complexity x survival. RESULTS: Multiple logistic regression identified RACHS-1 category to be a powerful predictor of mortality (Wald 17.7, p < 0.0001), whereas Aristotle Score was only weakly associated with mortality (Wald 4.8, p = 0.03). Age at operation and bypass time were also highly significant predictors of postoperative death (Wald 13.7 and 33.8, respectively, p < 0.0001 for both). Operative performance was measured at 7.52 units. CONCLUSIONS: The Basic Aristotle Score was only weakly associated with postoperative mortality in this series. Operative performance appeared to be inflated by the fact that the overall complexity of cases was relatively high in this series. An alternative equation (performance = complexity/mortality) is proposed as a fairer and more logical method of risk-adjustment.