Assessment of laboratory and clinical features of patients with right ventricular outflow tract obstruction at choray hospital – Le Thanh Khanh Van

Journal of military pharmaco-medicine n o 7-2018 172 ASSESSMENT OF LABORATORY AND CLINICAL FEATURES OF PATIENTS WITH RIGHT VENTRICULAR OUTFLOW TRACT OBSTRUCTION AT CHORAY HOSPITAL Le Thanh Khanh Van*; Mai Van Vien**; Pham Tho Tuan Anh* SUMMARY Objectives: To investigate laboratory and clinical characteristics of patients with right ventricular outflow tract obstruction at Choray Hospital. Subjects and methods: An prospective study of 75 patients, who were surgically corrected for right ventricular outflow tract obstruction at Choray Hospital during period of 2013 - 2017. Results: 75 patients (female: 62.7%, male: 37.3%, age: 6 ± 15.5, BSA: 0.8 ± 0.5 m2) admitted to Choray Hospital during the period from 2013 to 2017 with a definitive diagnosis of right ventricular outflow tract obstruction and resulting surgical relief of right ventricular outflow tract. Cyanosis was recorded in 85.3% of patients, clubbing in 28%, and tet spells in 10.7%. Patients who had preoperative dyspnea were reported to have of NYHA II in 80% and of NYHA III in 20%, the mean SpO2 of 84.4 ± 7.1%. Transpulmonary valve pressure gradient in transthoracic echocardiography was 89.8 ± 24.2 mmHg, single right ventricular outflow tract obstruction 5.3%, right ventricular outflow tract obstruction with VSD 6.7%, right ventricular outflow tract obstruction with ASD 9.3%, tetralogy of Fallot 78.7%, laboratory results showed red blood cell count 5.9 ± 1.3 x 1012/L, mean hemoglobin 155 ± 30.2 g/L, hematocrite 48.4 ± 10%, platelet 267.8 ± 96.3 x 109/L. The mortality rate was 2.6% (2 cases). Conclusions: Right ventricular outflow tract obstruction is a congenital heart disease usually manifesting clinically early after birth. Cyanosis appears early and worsens when children grows up depending on the location and obstruction severity of the right ventricular outflow tract. Prompt diagnosis and treatment often yield a good prognosis. * Keywords: Right ventricular outflow tract obstruction; Tetralogy of Fallot; Pulmonary artery stenosis. INTRODUCTION Congenital right ventricular outflow tract (RVOT) obstruction may be occurred at the pulmonary valvular level, subvalvular level, supravalvular level or multiple levels. Isolated pulmonary stenosis occurs in 8% to 12% of all congenital heart defects. The physiologic consequences and the clinical presentation of the patient are dependent upon the degree and the location of the RVOT obstruction. Most patients are symptomatic with cyanosis at birth or shortly thereafter and the severity of cyanosis depends on the severity and the anatomic location of the obstruction. Cyanosis appears early, worsens with age and affects the cognitive and motor development. * Choray Hospital ** 108 Central Military Hospital Corresponding author: Le Thanh Khanh Van (khanhvanleth@gmail.com) Date received: 13/07/2018 Date accepted: 30/08/2018 Journal of military pharmaco-medicine n o 7-2018 173 With development of modern medical techniques, congenital RVOT obstruction can be early detected and consequently. An appropriate strategy for management of patient will result in good outcomes. Therefore, we conducted a study: To assess the clinical and laboratory characteristics of the patients with the RVOT obstruction at Choray Hospital and determine an appropriate strategies of management. SUBJECTS AND METHODS 1. Subjetcs. All patients were diagnosed with RVOT obstruction and treated at Choray Hospital in the 4 year period from 2013 to 2017, regardless of age, sex and occupation. 2. Methods. A prospective study of 75 patients who were surgically corrected for RVOT obstruction at Choray Hospital during 2013 - 2017. Medical records had all necessary data required for research. All patients had been assessed the severity of dyspnea, the severity of heart failure, the anatomic location and severity of RVOT obstruction by physical examinations, laboratory tests and imaging. The severity of RVOT obstruction was assessed and compared with Z-score scale. * Data analysis: The research data was imported and processed by computerized statistical methods on computer with Microsoft Excel and Stata 12 software. RESULTS We recruited 75 patients (female: 62.7%, male: 37.3%, age: 6 ± 15.5, BSA: 0.8 ± 0.5 m2) admitted to Choray Hospital in the period from 2013 to 2017 with the diagnosis of RVOT obstruction. Patients were surgically corrected for RVOT obstruction depend upon the anatomic location and the degree of RVOT obstruction. The mortality rate was 2.6% (02 patients). In this study, 59 patients (78.7%) had tetralogy of Fallot, with ASD in 9.3% of cases and with VSD in 6.7% of cases, and the rest of patients (5.3% of cases) had isolated RVOT obstruction. Table 1: Features of subjects. Index Median SD Min Max Age 6 15.5 1 47 Weight (kg) 22 18.9 6.5 65 BSA (m2) 0.8 0.5 0.3 1.7 (SD: Standard deviation; Min: Minimum value; Max: Maximum value) Table 2: Preoperative clinical features of the patients (n = 75). Features Frequency Rate (%) Cyanosis 64 85.3 Clubbing 21 28 Hypoxic spells 8 10.7 Journal of military pharmaco-medicine n o 7-2018 174 NYHA Degree I 0 0 Degree II 60 80 Degree III 15 20 Table 3: Preoperative SpO2 of patients (n = 75). Index M SD Min Max Preoperative SpO2 84,4 7,1 70 99 Table 4: Preoperative blood test (n = 75). Table 5: Preoperative Doppler echocardiography (n = 75). * Number of obstructive lesions of RVOT (n = 75): The majority of the patients had 2 obstructive lesions (34 patients = 45.3%), 24 patients (32%) had 3 obstructive lesions and 17 patient (23.7%) had only 1 obstructive lesion. * Associated cardiac features (n = 75): The incidence of tetralogy of Fallot patients was the highest (59 patients = 78.7%), 7 patients (9.3%) had RVOT obstruction and ASD, 5 patients (6.7%) had RVOT obstruction and VSD, the rest of patients (4 patients = 5.3%) had isolated RVOT obstruction. 24 patients (32%) had patent foramen ovale, 11 patients (14.7%) had tricuspid valve regurgitation. * The incidence of patients had previous bypass thoracic shunt: Yes: 7 patients (9.3%); no: 68 patients (90.7%). Index M Median SD Min Max Red blood cells (x 1012/L) 5.9 5.6 1.3 3.7 10.2 Hemoglobine (g/L) 155 153 30.2 93.3 233 Hct (%) 48.4 46.6 10 29.8 71.4 Platelet (x 109/L ) 267.8 260 96.3 36 535 Index M Median SD Min Max Gradient right ventricular pulmonary artery (mmHg) 89.8 90 24.2 41 174 Z score PA -2.2 -1.7 2.6 -8.9 3.6 MPA -2.1 -2.2 2.8 -8.1 5.5 LPA 0.3 0.5 2.1 -6.3 5.8 RPA 0.3 0.3 1.7 -3.7 4.8 EF (%) 69.3 70 5.8 56 81 Journal of military pharmaco-medicine n o 7-2018 175 DISCUSSIONS Right ventricular outflow tract obstruction is a congenital heart defect which can be detected early at birth or thereafter whenever patients become symptomatic with cyanosis, dyspnea, chest discomfort, or palpitation. In addition, advances in diagnosis with modern imaging techniques such as cardiac echography, chest CT- scan, cardiac MRI as well as other invasive techniques such as cardiac catheterization have a crucial role in early diagnosis of RVOT obstruction. These advanced tools can help to diagnose the location and the degree of RVOT obstruction adequately and completely. Thus, depending on the location and severity of RVOT obstruction, we can detail a strategic plan in surgical correction, as well as other supportive treatments. These supportive treatments can be a minimal invasive intervention such as relief of pulmonary artery stenosis by balloon dilation or a cardiac surgery such as intracardiac repair or palliative shunts, surgical pulmonary valvutomy, or widening the RVOT by placing a fabric patch. In our study, patients were presented to hospital with significant symptoms of RVOT obstruction. Cyanosis was recorded in 85.3% of patients, clubbing was recorded in 28%. This date was similar to those from Dang Thi Hai Van’s [4], Nguyen Thu Trang’s [3] study. Mean SpO2 in preoperative dyspneic patients of our study was 84.4 ± 7.1%. In addition, we used transthoracic echocardiography to estimate mean gradient across the RVOT obstruction and it was 89.8 ± 24.2 mmHg. Therefore, all patients in our study had surgical indication to widen RVOT. The pathology in our study is quite diverse as in Kirklin’s classic paper [5]: the highest incidence was RVOT obstruction in tetralogy of Fallot (78.7%), the next one was RVOT obstruction with ASD (9.3%), and the last one was RVOT obstruction with VSD (6.7%). Therefore, we had to repair all defects completely and adequately. In particular, we have identified the location and the number of obstructive lesions. Obstruction of RVOT at more than 2 locations was the majority (77.3%). This helped us to predict all difficulties that we would have to deal with during the operations and make detail plans to correct defects in a way fitting with physiology and anatomy of the heart. Cardiopulmonary bypass time and aortic cross-clamping time would be longer and more likely to affect the recovery of patient at intensive care units. Preoperative blood tests of patients in the study showed an increase in red blood cells (5.9 ± 1.3 milion/L) and hemoglobine levels (155 ± 30.2 g/L). These results were similar to the results published previously. Journal of military pharmaco-medicine n o 7-2018 176 CONCLUSIONS Right ventricular outflow tract obstruction is a congenital heart defect which clinical manifestations can be detected early after birth. Cyanosis appears early and worsens with aging and it is dependent upon the location and severity of the obstruction of RVOT. Early diagnosis and appropriate treatment will lead to good outcomes. REFERENCES 1. Pediatric Treatment Regimen. Medical Publishing House. 2013, pp.578-579. 2. Phan Kim Phuong, Nguyen Van Phan, Pham Nguyen Vinh. Results of intracardiac repair of tetralogy of Fallot recorded over 240 cases at Hochiminh City. Institute of Hearts Hochiminh City. 1996, pp.116-117. 3. Nguyen Thu Trang. Clinical and testing observations of tetralogy of Fallot disease in children treated at the Xanh Pon Hospital. Gradational Lecture of General Practitioner of Hanoi Medical University. 2005. 4. Dang Thi Hai Van. Clinical and testing features of children with tetralogy of Fallot. Pediatric Journal. 2013, 6, 2. 5. Kirklin, Barratt Boyes. Cardiac Surgery. Third edition. 2013, Vol 1, pp.41-45.