Cardiovascular Surgery and Interventions 2022, Vol 9, Num 2 Page(s): 073-080
Evaluation of mortality scores in patients with adult congenital heart defects
DOI: 10.5606/e-cvsi.2022.1223
Berra Zümrüt Tan-Recep, Eylem Tuncer, Nihat Cine, Hakan Ceyran
Department of Pediatric Cardiac Surgery, Kartal Koşuyolu Yüksek Ihtisas Training and Research Hospital, Istanbul, Türkiye
Keywords: Adult congenital heart surgery score; aristotle basic complexity score; mortality; society of thoracic surgery european association for cardiothoracic surgery score
Objectives: Currently, there is no approved risk stratification for adult congenital heart surgery; accordingly, this study aimed to evaluate risk stratification for congenital heart surgery in the pediatric age in terms of its prognostic value in adult patients as well as the effectiveness of the newly developed Adult Congenital Heart Surgery (ACHS) score in this patient group.

Patients and methods: A total of 205 patients (115 males, 90 females; mean age: 25.0±11.4 years; range, 18 to 65 years) operated on due to congenital heart disease between January 1, 2011, and August 1, 2019, were studied retrospectively. Aristotle Basic Complexity (ABC) score, Society of Thoracic Surgery European Association for Cardiothoracic Surgery (STAT) score, and ACHS score were evaluated. Receiver operating characteristic (ROC) curves were created to evaluate the ability of scoring systems to predict mortality.

Results: The mortality rate was 4.4% (n=9). For mortality, areas under the ROC curve were 0.89, 0.89, and 0.70 for ABC, STAT, and ACHS scores, respectively. The mean ACHS score was 0.42±0.34. The cut-off point of the ACHS score was identified as 0.7 and above. The specificity of the cut-off value of 0.7 regarding the ACHS score was 94.39%. Adult Congenital Heart Surgery scores were found to be statistically high in patients with mortality (p=0.037; p<0.05).

Conclusion: Adult Congenital Heart Surgery scores had higher specificity in determining mortality in cases with an ACHS score of 0.7 and above. The ACHS score could also be used to determine the expected mortality rate, similar to the ABC and STAT scores.

  • Top
  • Summary
  • Introduction
  • Methods
  • Results
  • Disscussion
  • References
  • In congenital heart disease, Aristotle Basic Complexity (ABC) and Society of Thoracic Surgery European Association for Cardiothoracic Surgery (STAT) scores are frequently used to determine mortality. In grown-up congenital heart (GUCH) patients, surgery is complex due to residual lesions, complications, or sequelae after previous palliative surgery or complete correction.[1]

    Previous studies reported that GUCH patients had several risk factors for morbidity and mortality after surgery. Mortality rates detected in GUCH patients are low; however, our knowledge about this growing population of patients is still limited.[2] This study aimed to determine the effectiveness of the Adult Congenital Heart Surgery (ACHS) score for early mortality in primary surgery and reoperations and compare it with ABC and STAT scores.

  • Top
  • Summary
  • Introduction
  • Methods
  • Results
  • Disscussion
  • References
  • In this retrospective study, 205 patients (115 males, 90 females; mean age: 25.0±11.4 years; range, 18 to 65 years) operated on due to congenital heart disease at the Kartal Koşuyolu Yüksek Ihtisas Training and Research Hospital between January 1, 2011, and August 1, 2019, were included. The patients were divided into 27 subgroups according to the type of operation. In our study, ABC and STAT mortality scores of each patient were calculated, and an ACHS score was given according to the procedures performed on the patients based on the studies conducted by Fuller et al.[1] in 2015. Patients who underwent multiple procedures during the operation were given an ACHS score with the highest mortality score. Mortality was determined as the hospital mortality.

    Statistical analysis
    The NCSS (Number Cruncher Statistical System) version 2007 (NCSS LLC., Kaysville, UT, USA) software was used for statistical analyses. Descriptive statistical methods (mean, standard deviation, median, frequency, ratio, minimum, maximum) were used to evaluate the data of the study. The compliance of the quantitative data with the normal distribution was tested via the Kolmogorov-Smirnov test, Shapiro-Wilk test, and graphical assessments. The Mann-Whitney U test was used to compare two groups that did not indicate normal data distribution. In the comparison of qualitative data, the Fisher-Freeman-Halton exact test and Fisher exact test were used. Diagnostic screening tests (sensitivity, specificity, positive predictive value, and negative predictive value) and ROC curve analysis were used to determine the cut-off value of the parameters. A p value of <0.05 was considered statistically significant.

  • Top
  • Summary
  • Introduction
  • Methods
  • Results
  • Disscussion
  • References
  • The distribution of the patients according to diagnoses, numbers of reoperations, and mortality is presented in Table 1. The most frequent diagnoses were ventricular septal defect with 14.1% (n=29), atrial septal defect with 13.7% (n=28), partial abnormal pulmonary venous return with 12.7% (n=26), partial atrioventricular septal defect with 9.3% (n=19), and pulmonary valve replacement with 7.3% (n=15).

    Table 1. Distribution of diagnoses, mortality and number of operation

    The ABC, STAT, and ACHS score distributions according to mortality are provided in Table 2. Mortality was observed in 4.4% (n=9) of the patients included in the study. In terms of mortality, statistically significant differences were identified for ABC, STAT (p=0.001; p<0.01), and ACHS scores (p=0.037; p>0.05); the scores of patients with mortality were higher. We used the binomial exact test (DeLong test) to compare the areas under the ROC curves. Accordingly, the ABC and STAT mortality scores were not significantly different in predicting mortality (p>0.05), whereas the ABC and ACHS scores were significantly associated (p<0.05). There was also a borderline significance between the STAT mortality score and the ACHS score (p≤0.05; Figure 1). Based on this significance, cut-off points were calculated for the scoring systems. The cut-off values and ROC curve results are given in Table 3 (Figure 2). The cut-off values were ≥9, ≥0.8, and ≥0.7 for the ABC, STAT, and ACHS scores, respectively, and a statistically significant difference was observed between these values (p=0.001; p <0.01). The numbers of reoperations and postoperative complications, the mortality scores of the patients who underwent reoperation, and the relevant ROC curve results are presented in Tables 4, 5, and 6, respectively (Figure 2).

    Table 2: Evaluation of aristotle basic, STAT and ACHS scores according to mortality

    Figure 1: ROC curves for ABC, STAT and ACHS scores by mortality.
    ROC: Receiver operating characteristic; ABC: Aristotle Basic Complexity score; STAT: Society of Thoracic Surgery European Association for Cardiothoracic Surgery; ACHS: Adult Congenital Heart Surgery.

    Table 3: Diagnostic screening tests and ROC curve results for ABC, STAT and ACHS score by mortality

    Figure 2: ROC curves for ABC, STAT and ACHS scores according to mortality in reoperated patients.
    ROC: Receiver operating characteristic; ABC: Aristotle Basic Complexity score; STAT: Society of Thoracic Surgery European Association for Cardiothoracic Surgery; ACHS: Adult Congenital Heart Surgery.

    Table 4: Distribution of reoperation and postoperative complication

    Table 5: Evaluation of ABC, STAT and ACHS scores according to mortality in reoperated patients

    Table 6: ROC curve results for ABC, STAT and ACHS scores in reoperated patients

  • Top
  • Summary
  • Introduction
  • Methods
  • Results
  • Disscussion
  • References
  • Adults with congenital heart disease make up a rapidly growing segment of the cardiovascular patient population.[2] In their study, Gilboa et al.[3] estimated that the number of patients reached 1.4 million. The incidence of congenital heart disease in Türkiye is about 1%, and there are approximately 12,000 new patients each year.[4] Today, more than 85% of children with congenital heart disease are expected to reach adulthood.[5,6]

    Risk stratification regarding the procedures is important in determining surgical mortality. In 2004, Lacour-Gayet et al.[7] developed the ABC score to assess surgeon performance in congenital heart surgery. In 2006, Kang et al.[8] demonstrated that this score is somewhat useful in determining mortality but cannot be used as a statistically significant tool. In 2007, O'Brien et al.[9] argued that the ABC score is useful for differentiating low-and high-risk patients. A 2011 study by Photiadis et al.[10] supported this opinion but indicated that the ABC score is based on the complexity of surgical procedures and does not take into account patient-related factors. In their 2012 study, Hörer et al.[11] demonstrated that the ABC score is not suitable for predicting mortality in combined surgical procedures.

    In 2014, Kogon et al.[12] published a study comparing the STAT and ABC scores. In this retrospective study, they argued that the scoring systems used in pediatric patients were also valuable in the adult group. They suggested that ABC and STAT scores had similar results in determining mortality; however, ABC score was more effective in determining major complications and length of hospitalization.

    In 2015, Cavalcanti et al.[13] argued that the ABC and STAT scores were not significantly different in predicting mortality. A 2016 study by Hörer et al.[14] suggested that the ABC score had a low predictive value but outperformed the STAT score. In 2019, Bobillo-Perez et al.[15] indicated that the predictive performance of the STAT score was better than that of the ABC score.[16]

    The controversial state of scoring systems in the adult group caused the search for a new scoring system. In their study published in 2015, Fuller et al.[1] suggested that the ACHS mortality score was effective. In this study, they divided the patients into 152 groups and determined an ACHS mortality score ranging from 0.1 to 3.0 for each. In 2019, Abouelella et al.[17] stated that the ACHS score is currently the best predictor of mortality in GUCH patients and that the mortality rate was 4%.

    In our study, we investigated the effectiveness of GUCH using this scoring system. In the present study, hospital mortality was 4.4% (n=9). In terms of mortality, statistically significant differences were identified for ABC, STAT (p=0.001; p<0.01), and ACHS scores (p=0.037; p>0.05); the scores of patients with mortality were higher (Table 3). In our study, we calculated the cut-off values and performed ROC curve analysis for the prediction of mortality. The ROC curve results for ABC, STAT, and ACHS scores for predicting mortality are given in Table 3. Based on this significance, cut-off points were calculated for the scoring systems. The incidence of mortality was 13.455 times higher in patients with a cut-off value of ≥0.7 in their ACHS mortality scores.

    Abouelella et al.[17] reported a postoperative complication rate of 18%, similar to the rate of 28% stated by Mascio et al.[18] The reported incidence of neurological complications is 7%.[19] In our study, postoperative complications were detected in 13.7% of the cases (n=28), and it is consistent with the literature (Table 4). In our study, extracorporeal membrane oxygenation was required in 10.7% (n=3) of patients (aortopulmonary shunt, n=1; pulmonary artery reconstruction, n=1; mitral valve repair, n=1) due to low cardiac output. All of these patients died while on support. Neurological complications were observed in 10.7% (n=3) of our patients, including one patient who underwent right ventricle to pulmonary artery conduit replacement and later died due to intracranial bleeding, as well as two patients who underwent pulmonary valve replacement and mitral valve replacement. These patients developed postoperative convulsions, but no pathologies were detected in their examinations; therefore, the condition was attributed to temporary ischemia and completely resolved with medical treatment.

    A statistically significant relationship was found between postoperative complication rates according to the occurrence of reoperation (p=0.002; p<0.01); the rate of postoperative complication incidents in those reoperated was higher than in those who were not reoperated. The ABC, STAT, and ACHS results of reoperated patients are demonstrated in Table 5. The ABC, STAT, and ACHS scores of the patients who underwent reoperation were significantly higher than the scores of those who did not. The areas under the ROC curves were 0.81 (p=0.001, p<0.01), 0.69 (p=0.001, p<0.01), and 0.62 (p=0.034, p<0.05), respectively.

    When the areas undser the ROC curve were compared, the ABC score was found to be more effective in predicting mortality than the ACHS score (p=0.001; p<0.01). The STAT mortality score and ACHS score were not significantly different (p=0.626; p>0.05; Table 6).

    The small sample size of the study is its main limitation. Some complex surgeries, such as Fontan operation, are rare in adulthood, and therefore the number of patients to be compared is small. Additionally, some data losses are not excluded due to the retrospective design.

    In conclusion, for primary operations, all scoring systems could significantly predict mortality; however, the ABC and STAT scores had better predictive value compared to the ACHS score. The predictive value of STAT and ACHS scores was similar in reoperations, whereas the ABC score had a higher predictive value. The ACHS mortality score has good predictive power in adult congenital heart patients. Preoperative risk prediction could be used safely to analyze surgical results.

    Ethics Committee Approval: The study protocol was approved by the Koşuyolu High Specialization Education and Research Hospital Ethics Committee (Date: 08.12.2020, no: 2020/13/390). The study was conducted in accordance with the principles of the Declaration of Helsinki.

    Patient Consent for Publication: A written informed consent was obtained from each patient.

    Data Sharing Statement: The data that support the findings of this study are available from the corresponding author upon reasonable request.

    Author Contributions: Idea/concept, design:B.Z.T.R.; Control/supervision: H.C., E.T.; Data collection and/or processing, analysis and/or interpretation: B.Z.T.R.; Literature review: B.Z.T.R., E.T.; Writting the article: B.Z.T.R.; Critical review: B.Z.T.R., H.C.; References and funding, materials: N.C.

    Conflict of Interest: The authors declared no conflicts of interest with respect to the authorship and/or publication of this article.

    Funding: The authors received no financial support for the research and/or authorship of this article.

  • Top
  • Summary
  • Introduction
  • Methods
  • Results
  • Discussion
  • References
  • 1) Fuller SM, He X, Jacobs JP, Pasquali SK, Gaynor JW, Mascio CE, et al. Estimating mortality risk for adult congenital heart surgery: An analysis of the society of thoracic surgeons congenital heart surgery database. Ann Thorac Surg 2015;100:1728-35.

    2) Dore A, de Guise P, Mercier LA. Transition of care to adult congenital heart centres: What do patients know about their heart condition? Can J Cardiol 2002;18:141-6.

    3) Gilboa SM, Devine OJ, Kucik JE, Oster ME, Riehle- Colarusso T, Nembhard WN, et al. Congenital heart defects in the United States: Estimating the magnitude of the affected population in 2010. Circulation 2016;134:101-9.

    4) Ündar A, Bakir I, Haydin S, Erek E, Ödemis E, Yivli P et al. Türkiye'de doğumsal kalp hastaliklari cerrahisinin bugünü ve yarını. Turkish Journal of Thoracic and Cardiovascular Surgery 2012;20:181-5.

    5) Deanfield J, Thaulow E, Warnes C, Webb G, Kolbel F, Hoffman A, et al. Management of grown up congenital heart disease. Eur Heart J 2003;24:1035-84.

    6) Warnes CA, Williams RG, Bashore TM, Child JS, Connolly HM, Dearani JA, et al. ACC/AHA 2008 guidelines for the management of adults with congenital heart disease: A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Writing Committee to Develop Guidelines on the Management of Adults With Congenital Heart Disease). Developed in Collaboration With the American Society of Echocardiography, Heart Rhythm Society, International Society for Adult Congenital Heart Disease, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J Am Coll Cardiol 2008;52:e143-e263.

    7) Lacour-Gayet F, Clarke D, Jacobs J, Comas J, Daebritz S, Daenen W, et al. The Aristotle Score: A complexity-adjusted method to evaluate surgical results. Eur J Cardiothorac Surg 2004;25:911-24.

    8) Kang N, Tsang VT, Elliott MJ, de Leval MR, Cole TJ. Does the Aristotle Score predict outcome in congenital heart surgery? Eur J Cardiothorac Surg 2006;29:986-8.

    9) O'Brien SM, Jacobs JP, Clarke DR, Maruszewski B, Jacobs ML, Walters HL 3rd, et al. Accuracy of the Aristotle Basic Complexity Score for classifying the mortality and morbidity potential of congenital heart surgery operations. Ann Thorac Surg 2007;84:2027-37.

    10) Photiadis J, Sinzobahamvya N, Arenz C, Sata S, Haun C, Schindler E, et al. Congenital heart surgery: Expected versus observed surgical performance according to the Aristotle Complexity Score. Thorac Cardiovasc Surg 2011;59:268-73.

    11) Hörer J, Vogt M, Wottke M, Cleuziou J, Kasnar-Samprec J, Lange R, et al. Evaluation of the Aristotle Complexity Models in adult patients with congenital heart disease. Eur J Cardiothorac Surg 2013;43:128-34.

    12) Kogon B, Oster M. Assessing surgical risk for adults with congenital heart disease: Are pediatric scoring systems appropriate? J Thorac Cardiovasc Surg 2014;147:666-71.

    13) Cavalcanti PE, Sá MP, Santos CA, Esmeraldo IM, Chaves ML, Lins RF, et al. Stratification of complexity in congenital heart surgery: Comparative study of the Risk Adjustment for Congenital Heart Surgery (RACHS-1) method, Aristotle Basic Score and Society of Thoracic Surgeons-European Association for Cardio- Thoracic Surgery (STS-EACTS) mortality score. Rev Bras Cir Cardiovasc 2015;30:148-58.

    14) Hörer J, Kasnar-Samprec J, Cleuziou J, Strbad M, Wottke M, Kaemmerer H, et al. Mortality following congenital heart surgery in adults can be predicted accurately by combining expert-based and evidence-based pediatric risk scores. World J Pediatr Congenit Heart Surg 2016;7:425-35.

    15) Bobillo-Perez S, Sanchez-de-Toledo J, Segura S, Girona- Alarcon M, Mele M, Sole-Ribalta A, et al. Risk stratification models for congenital heart surgery in children: Comparative single-center study. Congenit Heart Dis 2019;14:1066-77.

    16) Yıldız O, Kasar T, Öztürk E, Tüzün B, Altın HF, Onan İS, et al. Analysis of congenital heart surgery results: A comparison of four risk scoring systems. Turk Gogus Kalp Dama 2018;26:200-6.

    17) Abouelella RS, Habib EA, AlHalees ZY, Alanazi MN, Ibhais ME, Alwadai AH. Outcome of cardiac surgery in adults with congenital heart disease: A single center experience. J Saudi Heart Assoc 2019;31:145-50.

    18) Mascio CE, Pasquali SK, Jacobs JP, Jacobs ML, Austin EH 3rd. Outcomes in adult congenital heart surgery: Analysis of the Society of Thoracic Surgeons database. J Thorac Cardiovasc Surg 2011;142:1090-7.

    19) Ballweg JA, Wernovsky G, Gaynor JW. Neurodevelopmental outcomes following congenital heart surgery. Pediatr Cardiol 2007;28:126-33.

  • Top
  • Summary
  • Introduction
  • Methods
  • Results
  • Discussion
  • References