Factors affecting perioperative mortality in tetralogy of Fallot

Trends in Tetralogy of Fallot-Related Mortality in the United States Between 1999 and 2020

We sought to identify mortality trends related to Tetralogy of Fallot (ToF) in the U.S. population, with specific emphasis on age-related, racial, and geographic differences. Death certificate data was retrieved from the CDC WONDER database, where crude mortality rate (CMR) and age-adjusted mortality rates (AAMR) with 95% CIs per 1,000,000 population were identified, along with annual percentage changes (APCs) and average annual percentage change (AAPC) determined by Joinpoint regression. From 1999 to 2020, a total of 5523 deaths were reported in association with ToF, with nearly half of all deaths occurring during the first year of life. The AAMR steadily decreased from 1999 to 2020 (AAPC: - 1.26, 95% CI - 2.29 to -0.38, p-value = 0.012). Males had a slightly higher AAMR (0.91) than females (0.77). Non-Hispanic (NH) Blacks/African Americans had a higher AAMR (1.00) compared with NH Whites (0.83). Infants less than a year old exhibited the highest CMRs among all age groups. Although lower rates were seen among all age strata < 45 years of age, deaths in patients > 45 years significantly increased from 2013 to 2020 (APC 6.17, 95% CI 0.79 to 20.35, p-value = 0.047). Rural areas consistently exhibited greater AAMRs and lesser declines over time compared to urban areas, with most deaths occurring in medical facilities. Over the last 2 decades in the US, the mortality rates associated with ToF have steadily decreased. Focusing resources on these higher risk populations may prove beneficial.

Developmental and Evolutionary Heart Adaptations Through Structure-Function Relationships

While the heart works as an efficient pump, it also has a high level of adaptivity by changing its structure to maintain function during healthy and diseased states. In this Review, we present examples of structure-function relationships across species and throughout embryonic development in mammals and birds. We also summarize current research on avian models aiming at understanding how biophysical and biological mechanisms closely interact during heart formation. We conclude by underscoring similarities between cardiac adaptations and structural changes over developmental and evolutionary time scales and how understanding the mechanisms behind these adaptations can help prevent or alleviate the effects of cardiac malformations and contribute to cardiac regeneration efforts.

Early surgical outcome for Tetralogy Of Fallot In An African Setting; A Tanzanian experience using retrospective analysis of hospital data

BACKGROUND

Tetralogy of Fallot (TOF) is typically treated in infancy but often done late in many resource-limited countries, jeopardizing surgical outcomes. This study examined the early results of children undergoing primary complete TOF repair at the Jakaya Kikwete Cardiac Institute (JKCI) in Tanzania, an emerging cardiac center in Eastern Africa.

METHODS

A retrospective cohort study of children ≤ 18 years undergoing primary TOF complete repair between 2019 and 2021 was conducted. Patients with complex TOF and those with obvious genetic syndrome were excluded. Data on socio-demography, pre-and postoperative cardiac complications, Intensive Care Unit (ICU) and hospital stay, and in-hospital and 30-day mortality were analyzed. Logistic regressions were employed to find the factors for mortality, ICU, and hospital stays.

RESULTS

The I02 children underwent primary TOF complete repair were majority male (65.7%; n = 67), with a median age of 3.0 years (IQR: 2-6), ranging from 3 months to 17 years.Only 20 patients (19.6%) were below one year of age. Almost all (90%; n = 92) were underweight, with a mean BMI of 14.6 + 3.1 kg/m2 Haematocrits were high, with a median of 48.7 (IQR: 37.4-59.0). The median oxygen saturation was 81% (IQR:72-93). Over a third of patients (38.2%; n = 39) needed Trans annular patch (TAP) during surgery. The median ICU stay was 72 h (IQR:48-120), with ICU duration exceeding three days for most patients. The median hospital stay was 8.5 days (IQR:7-11), with 70 patients (68.2%)experiencing an extended hospital stay of > 7 days. Bacterial sepsis was more common than surgical site infection (5.6%; n = 6 vs. 0.9%;n = 1). No patient needed re-operation for the period of follow up. The in-hospital mortality rate was 5.9%, with no deaths occurring in children less than one year of age nor after discharge during the 30-day follow-up period. No statistically significant differences were observed in outcomes in relation to age, sex, levels of hematocrit and saturations, presence of medical illnesses, and placement of TAP.

CONCLUSION

TOF repairs in this African setting at a national cardiac referral hospital face challenges associated with patients' older age and compromised nutritional status during the surgery. Perioperative mortality rates and morbidity for patients operated at an older age remain elevated. It's important to address these issues to improve outcomes in these settings.

The American Association for Thoracic Surgery (AATS) 2022 Expert Consensus Document: Management of infants and neonates with tetralogy of Fallot

OBJECTIVE

Despite decades of experience, aspects of the management of tetralogy of Fallot with pulmonary stenosis (TOF) remain controversial. Practitioners must consider newer, evolving treatment strategies with limited data to guide decision making. Therefore, the TOF Clinical Practice Standards Committee was commissioned by the American Association for Thoracic Surgery to provide a framework on this topic, focused on timing and types of interventions, management of high-risk patients, technical considerations during interventions, and best practices for assessment of outcomes of the interventions. In addition, the group was tasked with identifying pertinent research questions for future investigations. It is recognized that variability in institutional experience could influence the application of this framework to clinical practice.

METHODS

The TOF Clinical Practice Standards Committee is a multinational, multidisciplinary group of cardiologists and surgeons with expertise in TOF. With the assistance of a medical librarian, a citation search in PubMed, Embase, Scopus, and Web of Science was performed using key words related to TOF and its management; the search was restricted to the English language and the year 2000 or later. Articles pertaining to pulmonary atresia, absent pulmonary valve, atrioventricular septal defects, and adult patients with TOF were excluded, as well as nonprimary sources such as review articles. This yielded nearly 20,000 results, of which 163 were included. Greater consideration was given to more recent studies, larger studies, and those using comparison groups with randomization or propensity score matching. Expert consensus statements with class of recommendation and level of evidence were developed using a modified Delphi method, requiring 80% of the member votes with 75% agreement on each statement.

RESULTS

In asymptomatic infants, complete surgical correction between age 3 and 6 months is reasonable to reduce the length of stay, rate of adverse events, and need for a transannular patch. In the majority of symptomatic neonates, both palliation and primary complete surgical correction are useful treatment options. It is reasonable to consider those with low birth weight or prematurity, small or discontinuous pulmonary arteries, chromosomal anomalies, other congenital anomalies, or other comorbidities such as intracranial hemorrhage, sepsis, or other end-organ compromise as high-risk patients. In these high-risk patients, palliation may be preferred; and, in patients with amenable anatomy, catheter-based procedures may prove favorable over surgical palliation.

CONCLUSIONS

Ongoing research will provide further insight into the role of catheter-based interventions. For complete surgical correction, both transatrial and transventricular approaches are effective; however, the smallest possible ventriculotomy should be utilized. When possible, the pulmonary valve should be spared; and if unsalvageable, reconstruction can be considered. At the conclusion of the operation, adequate relief of the right ventricular outflow obstruction should be confirmed, and identification of a significant fixed anatomical obstruction should prompt further intervention. Given our current knowledge and the gaps identified, we propose several key questions to be answered by future research and potentially by a TOF registry: When to palliate or proceed with complete surgical correction, as well as the ideal type of palliation; the optimal surgical approach for complete repair for the best long-term preservation of right ventricular function; and the utility, efficacy, and durability of various pulmonary valve preservation and reconstruction techniques.

Routine Perioperative Esmolol After Infant Tetralogy of Fallot Repair: Single-Center Retrospective Study of Hemodynamics

OBJECTIVES

Currently, surgical repair of tetralogy of Fallot (TOF) is associated with an 1.1% 30-day mortality rate. Those with junctional ectopic tachycardia (JET) and restrictive right ventricular physiology have poorer outcomes. Routine postoperative adrenergic or inodilator therapy has been reported, while beta-blockade following cardiopulmonary bypass has not. This study evaluated routine perioperative treatment with esmolol in infants undergoing TOF repair.

DESIGN

Retrospective chart review of the perioperative course following TOF repair.

SETTING

Single-center case series describing perioperative management of TOF in a cardiac ICU.

PATIENTS

This study reviewed all patients less than 18 months old who underwent TOF repair, excluding cases of TOF with absent pulmonary valve or atrioventricular septal defect, at our institution from June 2018 to April 2021.

INTERVENTIONS

This review investigates the hemodynamic effects of esmolol following cardiopulmonary bypass for TOF repair.

MEASUREMENTS AND MAIN RESULTS

Preoperative clinical characteristics and perioperative course were extracted from the medical record. Descriptive statistics were used. Twenty-six patients receiving perioperative esmolol after TOF repair were identified and included. Postoperative hemodynamic parameters were within a narrow range with minimal vasoactive support in most patients. Three of 26 patients experienced JET, and one of 26 of whom had a brief cardiac arrest. Median and interquartile range (IQR) for hospital and postoperative length of stay was 7 days (IQR, 6-9 d) and 6 days (IQR, 5-8 d), respectively. There were no 30-day or 1-year mortalities.

CONCLUSIONS

In this infant cohort, our experience is that the routine use of postoperative esmolol is associated with good cardiac output with minimal requirement for vasoactive support in most patients. We believe optimal postoperative management of infant TOF repair requires a meticulous multidisciplinary approach, which in our experience is enhanced with routine postoperative esmolol treatment.

Mortality Risk Factors in Tetralogy of Fallot Patients Undergoing Total Correction

A total correction is a preferred treatment for Tetralogy of Fallot patients in every part of the world. However, the mortality in developing countries was as high as 6.9% to 15.3%. This was a retrospective analytic study that analyzed pre and post-operative risk factors that affected mortality on TOF patients that were performed total correction in Indonesia. A total of 47 TOF patients that were performed total correction from January 2016 to September 2019 were enrolled in this study based on the inclusion criteria. Preoperative and post-operative data were obtained from medical records. In this research, the majority of mortality was found in male patients (39.3%), while the female’s rate was lower (36.8%). Overall mortality was 38.3% and one operative death was found. The average age of patients was 84.12 months (12-210 months), whereas the average height (85.56 ± 36.17cm vs. 112.93 ± 21.73) and weight (17.22kg vs. 28.21kg) were lower for mortality patients. Some significant preoperative variables were identified as mortality risk factors such as: age below 60 months (p=0.047), smaller weight and height (p=0.008; p=0.002), abnormal hematocrit (p=0.002), and oxygen saturation below 75% (p=0.018). Significant post-operative risk factors included: temperature above 38.5⁰C (p=0.000), and ventilator time of more than 48 hours (p=0.033). In conclusion, the mortality of TOF patients undergoing a total correction in developing countries was quite high. It was associated with some risk factors, such as younger age, lower weight and height, low oxygen saturation, post-operative fever, and prolonged ventilator time.

Impact of Perioperative Tachydysrhythmias on Mortality and Length of Stay in Complete Repair of Tetralogy of Fallot: A Multicenter Retrospective Cohort Study from the Pediatric Health Information System

INTRODUCTION

Tachydysrhythmias (TDS) frequently occur after complete repair of tetralogy of Fallot (TOF). However, not much is known about the effect of TDS on morbidity and mortality after TOF repair. We sought to assess the associations between TDS and mortality and morbidity after repair of TOF using a multicentre database.

MATERIALS AND METHODS

We identified all children aged 0-5 years in the Pediatric Health Information System who underwent TOF repair between 2004 and 2015. Codes for TDS were used to identify cases. Outcome variables were inpatient mortality and total length of stay (LOS). Univariate and multiple logistic and linear regression analyses were used to identify the effects of multiple risk factors, including TDS, on mortality and LOS.

RESULTS

A total of 7,749 patients met inclusion criteria, of which 1,493 (19%) had codes for TDS. There was no association between TDS and inpatient mortality. However, TDS were associated with 1.1 days longer LOS and accounted for 2% of the variation observed in LOS.

CONCLUSION

After complete repair of TOF, TDS were not associated with mortality and appeared to have only a modest effect on LOS.

Junctional Ectopic Tachycardia: Recognition and Modern Management Strategies

Junctional ectopic tachycardia is a common dysrhythmia after congenital heart surgery that is associated with increased perioperative morbidity and mortality. Risk factors for development of junctional ectopic tachycardia include young age (neonatal and infant age groups); hypomagnesemia; higher-complexity surgical procedure, especially near the atrioventricular node or His bundle; and use of exogenous catecholamines such as dopamine and epinephrine. Critical care nurses play a vital role in early recognition of dysrhythmias after congenital heart surgery, assessment of hemodynamics affecting cardiac output, and monitoring the effects of antiarrhythmic therapy. This article reviews the underlying mechanisms of junctional ectopic tachycardia, incidence and risk factors, and treatment options. Currently, amiodarone is the pharmacological treatment of choice, with dexmedetomidine increasingly used because of its anti-arrhythmic properties and sedative effect.

Pulmonary valve annular and right ventricular outflow tract size as predictions values for moderate to severe pulmonary regurgitation after repaired Tetralogy of Fallot

OBJECTIVE

This study sought to investigate the variation of right heart structure pre- and post-operation as risk factors for moderate to severe pulmonary regurgitation (PR) after repaired Tetralogy of Fallot and the best "cutoff" values for the transannular patch (TAP).

METHODS

We collected surgical, echocardiographic, and computed tomographic data of Teralogy of Fallot (TOF) patients over two years and calculated z-score values based on the echocardiographic data. Based on the PR level after follow-up, the patients were divided into two groups, trivial to mild PR and moderate to severe PR. A multivariate logistic regression analysis was performed, and the receiver operating characteristic curve analysis was used to find the best "cutoff" value for risk factors.

RESULTS

A total of 104 TOF patients were included in our cohort study. From the multivariate analysis, correction strategy (P = .002), difference in zRVOT (OR 1.974, 95% CI 1.354 to 2.878, P < .0001), and zPVA (OR 3.605, 95% CI 1.980 to 6.562, P < .0001) were the significant risk factors for moderate to severe PR. The "cutoff" value for the difference in zPVA that could predict moderate to severe PR in the TAP group was 3, and the optimal "cutoff" value for TAP was -1.4.

CONCLUSIONS

The TAP is a risk factor for significant PR after surgery. We recommend the optimal "cutoff" value for TAP is -1.4 calculated using Shan-Shan Wang's data set. During the procedure, to limit the RVOT resection and restrict the enlargement of pulmonary annulus within a variation of z-score as 3 would reduce significant PR.

Surgical outcomes in complex adult congenital heart disease: a brief review

Life expectancy of patients with congenital heart disease (CHD) continues to increase dramatically over the last few decades, primarily due to significant medical and surgical advancements in the field. Adult congenital heart disease (ACHD) patients are now living longer but continue to face morbidity and reduced long-term survival when compared to the general population. We briefly describe the growth of ACHD with a focus on surgical procedures and outcomes in the more complex lesions including Tetralogy of Fallot, Ebsteins Anomaly of the tricuspid valve, Coarctation of the Aorta, Transposition of the Great Arteries and single ventricle lesions. The advancing role of mechanical circulatory support and cardiac transplantation in ACHD patients is also highlighted. Cardiac surgery in these patients continues to improve with low surgical mortality rate and outstanding long-term outcomes and efficacy.

Factors associated with perioperative mortality in children and adolescents operated for tetralogy of Fallot: A sub-Saharan experience

BACKGROUND

Patients with tetralogy of Fallot are now surviving to adulthood with timely surgical intervention. However, many patients in low-income countries have no access to surgical intervention. This paper reports the surgical access and perioperative mortality in a sub-Saharan center that was mainly dependent on visiting teams.

METHODS

We reviewed records of patients operated from January 2009 to December 2014. We examined perioperative outcomes, primarily focusing on factors associated with perioperative mortality.

RESULTS

During this period, 62 patients underwent surgery. Fifty-seven (91.9%) underwent primary repair, while 5 (6.5%) underwent palliative shunt surgery. Of the five patients with shunt surgery, four ultimately underwent total repair. Eight (12.9%) patients died during the perioperative period. Factors associated with perioperative mortality include repeated preoperative phlebotomy procedures (P < .001), repeated runs and long cardiopulmonary bypass time (P < .001), and aortic cross-clamp time (P < .001), narrow pulmonary artery (PA) valve annulus diameter (P = .022), narrow distal main PA diameter (P = .039), narrow left branch PA diameter (P = .049), and narrow right PA diameter (P = .039). Of these factors, cardiopulmonary bypass time/aortic cross-clamp time and pulmonary valve annulus diameter less than three SD were independently associated with perioperative mortality.

CONCLUSION

In this series of consecutive patients operated by a variety of humanitarian surgical teams, cardiopulmonary bypass time/aortic cross-clamp time, and pulmonary valve annulus diameter less than three SD were independently associated with perioperative mortality risk. As some of these factors are modifiable, we suggest that they should be considered during patient selection and at the time of surgical intervention.

Current outcomes and treatment of tetralogy of Fallot

Tetralogy of Fallot (ToF) is the most common type of cyanotic congenital heart disease. Since the first surgical repair in 1954, treatment has continuously improved. The treatment strategies currently used in the treatment of ToF result in excellent long-term survival (30 year survival ranges from 68.5% to 90.5%). However, residual problems such as right ventricular outflow tract obstruction, pulmonary regurgitation, and (ventricular) arrhythmia are common and often require re-interventions. Right ventricular dysfunction can be seen following longstanding pulmonary regurgitation and/or stenosis. Performing pulmonary valve replacement or relief of pulmonary stenosis before irreversible right ventricular dysfunction occurs is important, but determining the optimal timing of pulmonary valve replacement is challenging for several reasons. The biological mechanisms underlying dysfunction of the right ventricle as seen in longstanding pulmonary regurgitation are poorly understood. Different methods of assessing the right ventricle are used to predict impending dysfunction. The atrioventricular, ventriculo-arterial and interventricular interactions of the right ventricle play an important role in right ventricle performance, but are not fully elucidated. In this review we present a brief overview of the history of ToF, describe the treatment strategies currently used, and outline the long-term survival, residual lesions, and re-interventions following repair. We discuss important remaining challenges and present the current state of the art regarding these challenges.

The impact of pulmonary valve-sparing techniques on postoperative early and midterm results in tetralogy of Fallot repair

Background

In this study, we analyzed the impact of pulmonary valve-sparing techniques on early and midterm postoperative results of tetralogy of Fallot repair.

Methods

A total of 64 patients diagnosed with tetralogy of Fallot, who underwent total correction operation by the same surgeon between November 2010 and September 2015 were included in this retrospective study. Mean age of the patients was 20.0±14.2 months (5.5-96 months). Forty patients (62.5%) were male. Thirty two of the patients (50%) were under one year of age. Pulmonary valve-sparing techniques were performed in 29 patients (Group 2), while transannular patch was applied in the remaining 35 patients (Group 1). Pericardial monocusp valve was constructed in 15 patients in Group 1. In Group 2, pulmonary valve-sparing techniques were transatrial repair in nine patients; transatrial-transpulmonary in eight, infundibular patch in eight, and infundibular-pulmonary patch in four patients.

Results

There was no early postoperative mortality in Group 2. Five patients (14.2%) in Group 1 died in the early postoperative period (p=0.058). Pulmonary monocusp insertion was performed in 2 (13.3%) of these patients (p=1). The causes of mortality were sudden cardiac arrest (n=2), multiorgan failure (n=1), low cardiac output (n=1), and neurological complications (n=1). Five patients in Group 1 required extracorporeal membrane oxygenation support (ECMO). Three of them were separated from ECMO and two of the patients that were separated were discharged uneventfully. Total postoperative morbidity rate was significantly higher in Group 1 (51.4% vs. 6.8%) (p=0.0001). Morbidity rate was significantly lower in patients with pulmonary monocusp insertion than patients in the same group without a monocusp (p=0.0176). Forty nine (83%) of the patients were followed up for a median of 6.5 (1-24) months. While free pulmonary regurgitation was detected in all non-monocusp patients in Group 1, pulmonary regurgitation was absent or mild in Group 2. Twelve (80%) of the patients in Group 1 who had monocusp insertion were followed up. Only two of these patients had free pulmonary regurgitation (16.6%). The rest of them had mild (n=6) or mildmoderate pulmonary regurgitation (n=4).

Conclusion

Mortality and morbidity rates are lower when pulmonary valvesparing techniques are used in repair of tetralogy of Fallot. Monocusp pulmonary valve insertion may improve results in patients who require transannular patch repair. It is suggested that every effort should be made to achieve a competently working pulmonary valve during repair.

Optimal Use of Z-Scores to Preserve the Pulmonary Valve Annulus During Repair of Tetralogy of Fallot

Objective:

The size of the pulmonary annulus measured as a z-score is often used to determine when to insert a transannular patch (TAP). Multiple “cutoffs” are quoted in the literature; this could lead to inappropriate insertion. We aimed to determine whether the use of z-scores derived from different populations may have contributed to the varied “cutoffs” quoted.

Methods:

PubMed was searched using the terms: “tetralogy,” “Fallot,” “transannular,” “patch,” “mortality,” and “death.” Studies published between January 1, 2005, and October 5, 2017, were included; studies without participants under the age of 18 years and studies that did not describe the operative procedure were excluded.

Results:

Of 52 papers retrieved, 19 were included representing 2,500 repaired patients; 1,371 (54.8%) had a TAP. Five (26.3%) papers representing 638 patients (25.5%) quoted a z-score “cutoff” and what data set was used; “cutoffs” ranged from −2 to −4 and were derived from 2 different data sets. Three studies quoted a data set that has been shown in previous work to be problematic; the only quoted “cutoffs” of −4 were from two of these studies.

Conclusions:

Surprisingly few (26.3%) studies mention what pulmonary annulus size “cutoff” was used to decide when to insert a TAP. Z-scores derived from different populations were used by different studies and it is possible that this may have contributed to the varied “cutoffs’ quoted. Recommendations to perform valve-sparing surgery in pulmonary annuli as small as −4 may not be warranted. Future papers should record “cutoffs” employing recommended z-score data set.

Effect of Concomitant Birth Defects and Genetic Anomalies on Infant Mortality in Tetralogy of Fallot

BACKGROUND

A substantial proportion of infants born with tetralogy of Fallot (TOF) die in infancy. A better understanding of the heterogeneity associated with TOF, including extracardiac malformations and chromosomal anomalies is vital to stratifying risk and optimizing outcomes during infancy.

METHODS

Using the North Carolina Birth Defects Monitoring Program, infants diagnosed with TOF and born between 2003 and 2012 were included. Kaplan-Meier survival curves were used to estimate cumulative 1-year mortality, stratified by the presence of concomitant birth defects (BDs) and chromosomal anomalies. Multivariable logistic regression was used to estimate the direct effect of each concomitant BD, after adjusting for all others.

RESULTS

A total of 496 infants with TOF were included, and 15% (n = 76) died. The number of concomitant BD systems was significantly associated with the risk of death at 1-year, p < 0.0001. Specifically, the risk of mortality was 8% among infants with TOF with or without additional cardiac defects, 16% among infants with TOF and 1 extracardiac BD system, 19% among infants with 2 extracardiac BD systems, and 39% among infants with ≥ 3 extracardiac BD systems. After adjustment, concomitant eye and gastrointestinal defects were significantly associated increased with 1-year mortality, odds ratio 2.83 (95% confidence interval, 1.08-7.32) and odds ratio 4.43 (95% confidence interval, 1.57, 12.45), respectively. Infants with trisomy 13 or trisomy 18 were also significantly more likely to die, p < 0.0001.

CONCLUSION

Both concomitant BDs and genetic anomalies increase the risk of mortality among infants with TOF. Future studies are needed to identify the underlying genetic and socioeconomic risk factors for high-risk TOF infants. Birth Defects Research 109:1154-1165, 2017. © 2017 Wiley Periodicals, Inc.

Pulmonary artery hypoplasia associated with posterior mediastinal hematoma accompanied by a ruptured pseudoaneurysm of the esophageal branch of the left gastric artery

A 65-year-old woman with no significant medical history visited the emergency department complaining of epigastric discomfort. A computed tomography of the thorax and abdomen showed the attenuation of the pulmonary artery and a posterior mediastinal hematoma. Angiography showed a tortuous esophageal branch of the left gastric artery and a pseudoaneurysm, and during the later phase, the left lower lobe of the lung was enhanced, and finally, the left pulmonary vein was enhanced. We considered that the patient was exhibiting hypoperfusion of the left pulmonary artery arising from left pulmonary artery hypoplasia, since the left lung was supplying the systemic circulation. Transcatheter arterial embolization was performed. The patient has not experienced any recurrence of a ruptured pseudoaneurysm or epigastric discomfort. Here, we report the first documented case of pulmonary artery hypoplasia associated with posterior mediastinal hematoma accompanied by a ruptured aneurysm of the left gastric artery.

Basic arterial blood gas biomarkers as a predictor of mortality in tetralogy of Fallot patients

Background:

Serum lactate and base deficit have been shown to be a predictor of morbidity and mortality in critically ill patients. Poor preoperative oxygenation appears to be one of the significant factors that affects early mortality in tetralogy of Fallot (TOF). There is little published literature evaluating the utility of serum lactate, base excess (BE), and oxygen partial pressure (PO₂) as simple, widely available, prognostic markers in patients undergoing surgical repair of TOF.

Materials and Methods:

This prospective, observational study was conducted in 150 TOF patients, undergoing elective intracardiac repair. PO₂, BE, and lactate levels at three different time intervals were recorded. Arterial blood samples were collected after induction (T1), after cardiopulmonary bypass (T2), and 48 h (T3) after surgery in the Intensive Care Unit (ICU). To observe the changes in PO₂, BE, and lactate levels over a period of time, repeated measures analysis was performed with Bonferroni method. The receiver operating characteristics (ROC) analysis was used to find area under curve (AUC) and cutoff values of various biomarkers for predicting mortality in ICU.

Results:

The patients who could not survive showed significant elevated lactate levels at baseline (T1) and postoperatively (T2) as compared to patients who survived after surgery (P < 0.001). However, in nonsurvivors, the BE value decreased significantly in the postoperative period in comparison to survivors (−2.8 ± 4.27 vs. 5.04 ± 2.06) (P < 0.001). In nonsurvivors, there was a significant fall of PO₂ to a mean value of 59.86 ± 15.09 in ICU (T3), whereas those who survived had a PO₂ of 125.86 ± 95.09 (P < 0.001). The ROC curve analysis showed that lactate levels (T3) have highest mortality predictive value (AUC: 96.9%) as compared to BE (AUC: 94.5%) and PO₂ (AUC: 81.1%).

Conclusion:

Serum lactate and BE may be used as prognostic markers to predict mortality in patients undergoing TOF repair. The routine analysis of these simple, fast, widely available, and cost-effective biomarkers should be encouraged to predict prognosis of TOF patients.