ABC | Volume 112, Nº2, February 2019

Original Article Fernandes et al Conversion to total cavopulmonary connection Arq Bras Cardiol. 2019; 112(2):130-135 Table 1 – Fontan operation performed between years 1995-2016 Fontan Type Number of patients Fontan-Kreutzer 18 (4.3%) Lateral Tunnel 82 (19.5%) TCPC with extra cardiac tube 320 (76.2%) Total 420 (100%) TCPC: total cavo-pulmonary connection. Objective The aim of this study is to evaluate the results of the conversion of FK to TCPC in patients with signs of univentricular circulation failure. Methods A retrospective review of medical records, in-hospital and outpatient notes, was performed for patients who underwent a Fontan conversion (FC). The inclusive criteria consisted of the conversion of FK to TCPC in the period of 1985 to 2016 regardless of their underlying pathology. This was a single center study performed in the Heart Institute (INCOR – HCFMUSP), São Paulo, Brazil. We reviewed all surgical records comprising age at procedure, ventricle morphology, indications for conversion, mortality, the presence of arrhythmias, functional class and the presence of comorbidities after correction. We excluded the patients in whom FC was indicated but the death occurred before the surgical procedure or intraoperatively, or in whom the procedure was not accepted by the patient or their surrogate decision maker. This study has been approved by the ethics committee of this Institution by the number CAAE 56617216.6.0000.0068. As the study is retrospective in nature, there was no need for the elaboration of a consent term. Statiscal analysis We used the Kolmogorov-Smirnov test to compare and chooose the sample of the study. Descriptive analysis was performed, including clinical and surgical characteristics. Continuous numerical variables were presented as median and interquartile range (IQR; 25th-75th percentile). Categorical variables were presented as frequencies, absolute number andpercentages. Variables with normal distributionwere presented average and standard deviation. Estimated actuarial survival were determined using the Kaplan-Meier method. Statistical analysis was performed with SPSS 23.0 for Windows (IBM Corp. Released 2015, IBM SPSS Statistics for Windows, Version 22.0, Armonk, NY: IBM Corp). Results The total number and type of FO performed are shown in Table 1. Of the 18 FK cases, 10 were elected for the conversion to the TCPC due to signs of Fontan circulation failure. All 10 patients previous FK were submitted to a FC procedure and all 10 were included in this study. The FK were conducted in the beginning of our experience, all were performed before the year 2004, most of them before the year 1999. Only 29 surgeries of lateral tunnels were performed after 2004 and after this year the most performed surgery was the TCPC with extra cardiac tube. A mortality of 11% (7,9% early deaths and 3,1% of late deaths) was observed for the FO procedure performed in this period. Regarding the ventricle morphology, we observed that 318 cases (75,7%) were classified as left ventricle, 57 (13,6%) as right ventricle, 40 (9,5%) had both ventricles and five (1,2%) had undefined ventricle. Analyzing the population of the converted, we observed that 40% of the patients were male and 60% female. The youngest patient who underwent conversion was 11 years old and the oldest patient was 42 years old, with the mean average of 23.2 years old. In nine cases (90%) the surgery was indicated for uncontrolled arrhythmia and one case was indicated by protein-losing enteropathy. In three cases, surgical cryoablation was performed in the same operative time. Before conversion three patients were in functional class I, four in functional class II and three in functional class III. We observed two deaths in the period, an early death (on the second postoperative day) due to significant bleeding and coagulopathy, and a late death (38th postoperative day) due to multiple sepsis and stroke. Both occurred during hospitalization in a postoperative intensive care unit (ICU). The actuarial survival of 5 and 10 years was 80%, as shown in Figure 1. After conversion, 80% of the patients who were in functional class II or higher evolved with functional class improvement. Currently, six patients are in functional class I (75%), one patient is in functional class II (12.5%) and one patient is in functional class III (12.5%). Regarding cardiac arrhythmias, 44% of conversions indicated by arrhythmias had improvements after conversion. Four cases were cured with no need of specialist follow-up and three cases had an arrhythmic condition that needed specialist flow-up. Before conversion, ventricular dysfunction was present in five patients. One of them evolved to death, and all the others had an improvement in their function in relation to the preoperative period, three of which currently have preserved function and one that had had moderate dysfunction previously, and now presents a slight dysfunction. These variables can be visualized on Table 2. For three of the cases in which surgical cryoablation was performed, one evolved to death despite of the arrhythmia. The other two cases had episodes of arrhythmia after conversion, one of which evolved to bradyarrhythmia requiring a pacemaker, and currently this patient is being evaluated for heart transplantation. The mean ICU length of stay (LOS) was 13 days, the shortest time was 2 days and the highest 38 days. The average total hospital LOS was 37 days, the shortest being 17 days and the highest 59 days. As complications, two patients presented bleeding, one pericarditis, one ischemic stroke, one presented convulsive 131