Displaying publications 1 - 20 of 35 in total

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  1. Poh ME, Liam CK, Rajadurai P, Chai CS
    J Thorac Dis, 2018 Jul;10(7):E560-E563.
    PMID: 30174934 DOI: 10.21037/jtd.2018.06.122
    We report the first case of epithelial-to-mesenchymal transition (EMT) as the cause of acquired resistance to the second-generation EGFR-tyrosine kinase inhibitor (TKI), afatinib in a patient with advanced non-small cell lung cancer (NSCLC) harboring a sensitizing EGFR mutation. Patients with EGFR-mutant NSCLC inevitably develop acquired resistance while on EGFR-TKI treatment. EMT which renders cancer cells more invasive and migratory is one of the mechanisms of acquired resistance to EGFR-TKIs and correlates with a poor prognosis. Possible therapeutic strategies in patients with EMT include blocking M2 muscarinic receptor signalling, targeting EMT with histone deacetylase inhibitors such as entinostat and MEK-inhibitors such as selumetinib, inhibition of microRNAs, immunotherapy and inhibiting fibroblast growth factor receptor-1.
  2. Kho SS, Nyanti LE, Chai CS, Tie ST
    ERJ Open Res, 2024 Jan;10(1).
    PMID: 38259810 DOI: 10.1183/23120541.00506-2023
    In PPL-TBLC, quality of tissue matters more than quantity for accurate diagnosis. Comparable diagnostic yield with 1.1-mm cryoprobe can potentially be achieved in 6 s of freezing and three or more passes. https://bit.ly/49cbmbW.
  3. Chai CS, Kho SS, Chan SK, Tee TT, Tie ST
    Clin Med (Lond), 2021 01;21(1):e114-e115.
    PMID: 33479093 DOI: 10.7861/clinmed.2020-0913
    Percutaneous vertebroplasty (PV) involves injection of polymethylmethacrylate bone cement into vertebral body for relief of pain and strengthening of bone in symptomatic vertebral compression fractures.Passage of bone cement into vertebral venous plexus and then into the lungs is a rare and serious complication of PV. The reported incidence up to 26%.We present an incidental finding of pulmonary cement embolism (PCE) after PV. A 68-year-old woman with history of PV 3 years previously for T11 osteoporotic fracture presented to us with cough for 3 weeks following choking on a fish bone.Chest X-ray showed left lower zone consolidation and a high-density opacity in a tubular branching pattern, corresponding to pulmonary arterial distribution. Contrasted computed tomography of the thorax showed segmental pulmonary cement embolism of both lungs and left lower lobe consolidation.She underwent bronchoscopy with findings of a purulent secretion from the left lower lobe. Her symptoms resolved after 2 weeks of antibiotics. She was managed conservatively for the PCE as she remained asymptomatic.This case highlights the need for a standard post-PV chest X-ray, as patients with cement embolisms can be completely asymptomatic. Measures to minimise the risk of pulmonary cement embolisms during PV need to be taken.
  4. Chan WY, Hamid MTR, Gowdh NFM, Rahmat K, Yaakup NA, Chai CS
    Curr Med Imaging, 2021;17(6):677-685.
    PMID: 33390122 DOI: 10.2174/1573405616666201231103312
    BACKGROUND: Coronavirus disease 2019 (COVID-19) is highly contagious and has claimed more than one million lives, besides causing hardship and disruptions. The Fleischner Society has recommended chest X-ray (CXR) in detecting cases at high risk of disease progression, for triaging suspected patients with moderate-to-severe illness, and for eliminating false negatives in areas with high pre-test probability or limited resources. Although CXR is less sensitive than real-- time reverse transcription-polymerase chain reaction (RT-PCR) in detecting mild COVID-19, it is nevertheless useful because of equipment portability, low cost and practicality in serial assessments of disease progression among hospitalized patients.

    OBJECTIVE: This study aims to review the typical and relatively atypical CXR manifestations of COVID-19 pneumonia in a tertiary care hospital.

    METHODS: The CXRs of 136 COVID-19 patients confirmed through real-time RT-PCR from March to May 2020 were reviewed. A literature search was performed using PubMed.

    RESULTS: A total of 54 patients had abnormal CXR whilst the others were normal. Typical CXR findings included pulmonary consolidation or ground-glass opacities in a multifocal, bilateral peripheral, or lower zone distribution, whereas atypical CXR features comprised cavitation and pleural effusion.

    CONCLUSION: Typical findings of COVID-19 infection in chest computed tomography studies can also be seen in CXR. The presence of atypical features associated with worse disease outcome. Recognition of these features on CXR will improve the accuracy and speed of diagnosing COVID-19 patients.

  5. Kho SS, Nyanti LE, Chai CS, Chan SK, Tie ST
    Clin Respir J, 2021 Jun;15(6):595-603.
    PMID: 33113256 DOI: 10.1111/crj.13297
    BACKGROUND: Although radial endobronchial ultrasound (rEBUS) is an important verification tool in guided bronchoscopy, a navigational route was not provided. Manual airway mapping allows the bronchoscopist to translate the bronchial branching in computed tomography (CT) into a comparable bronchoscopic road map. We aimed to explore the feasibility of this technique in navigating conventional rEBUS bronchoscopy in the localisation of peripheral pulmonary lesion by determining navigation success and diagnostic yield.

    METHODS: Retrospective review of consecutive rEBUS bronchoscopy performed with a 6.2 mm conventional bronchoscope navigated via manual bronchial branch reading technique over 18 months.

    RESULTS: Ninety-eight target lesions were included. Median lesion size was 2.67 cm (IQR 2.22-3.38) with 96.9% demonstrating positive CT bronchus sign. Majority (86.7%) of lesions were situated in between the third and fifth airway generations. Procedure was performed with endotracheal intubation in 43.9% and fluoroscopy in 72.4%. 98.9% of lesions were successfully navigated and verified by rEBUS following the pre-planned airway road map. Bidirectional guiding device was employed in 29.6% of cases. Clinical diagnosis was secured in 88.8% of cases, majority of which were malignant disease. The discrepancy between navigation success and diagnostic yield was 10.1%. Target PPL located within five airway generations was associated with better diagnostic yield (95.1% vs. 58.8%, P 

  6. Ng DL, Gan GG, Chai CS, Chee KH, Tan KL, Tan SB, et al.
    Patient Prefer Adherence, 2019;13:1363-1373.
    PMID: 31616136 DOI: 10.2147/PPA.S204246
    Introduction and aim: Patient quality of life (QOL) while on long-term oral anticoagulant therapy has been receiving greater attention in recent years due to the increase in life expectancy brought about by advances in medical care. This study aimed to compare the QOL, treatment satisfaction, hospitalization and bleeding rate in patients on long-term warfarin versus direct oral anticoagulants (DOAC).

    Methods: This was a cross-sectional study of patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE) on long-term anticoagulant therapy attending the cardiology clinic and anticoagulation clinic of the University Malaya Medical Centre from July 1, 2016, to June 30, 2018. Patient QOL was assessed by using the Short Form 12 Health Survey (SF12), while treatment satisfaction was assessed by using the Perception of Anticoagulation Treatment Questionnaire 2 (PACT-Q2).

    Results: A total of 208 patients were recruited; 52.4% received warfarin and 47.6% received DOAC. There was no significant difference in QOL between warfarin and DOAC based on SF12 (physical QOL, P=0.083; mental QOL, P=0.665). Nevertheless, patients in the DOAC group were significantly more satisfied with their treatment compared to the warfarin group based on PACT-Q2 (P=0.004). The hospitalisation rate was significantly higher in the warfarin group than the DOAC group (15.6% versus 3.0%, P=0.002). Clinically relevant minor bleeds and severe bleeding events were non-significantly higher in the warfarin group than the DOAC group (66.7% versus 40.0%, P=0.069).

    Conclusion: Compared to warfarin, treatment of NVAF and VTE with DOAC showed comparable QOL, higher treatment satisfaction, lesser hospitalization, and a non-significant trend toward fewer bleeding episodes.

  7. Puthiaparampil T, Rahman MM, Shazrina AR, Nariman S, Lukas S, Chai CS, et al.
    Med J Malaysia, 2022 Nov;77(6):724-729.
    PMID: 36448391
    INTRODUCTION: Our faculty used one long case (LC) and three short cases for the clinical component of the final professional examinations. During the COVID-19 pandemic, the LC had to be replaced with scenario-based clinical examination (SBCE) due to the impracticability of using recently hospitalised patients. While keeping the short case component as usual, the LC had to be replaced with SBCE in 2020 for the first time at a short notice. To evaluate the positive and negative aspects of SBCE and LC to determine the feasibility of replacing LC with SBCE in future examinations.

    MATERIALS AND METHODS: We compared the LC scores of three previous years with those of the SBCE and studied the feedback of the three stakeholders: students, examiners, and simulated patients (SPs), regarding their experience with SBCE and the suitability of SBCE as an alternative for LC in future examinations.

    RESULTS: The SBCE scores were higher than those of the LC. Most of the examiners and students were not in favour of SBCE replacing LC, as such. The SPs were more positive about the proposition. The comments of the three stakeholders brought out the plus and minus points of LC and SBCE, which prompted our proposals to make SBCE more practical for future examinations.

    CONCLUSION: Having analysed the feedback of the stakeholders, and the positive and negative aspects of LC and SBCE, it was evident that SBCE needed improvements. We have proposed eight modifications to SBCE to make it a viable alternative for LC.

  8. Ngu NH, Chai CS, Chan SK, Kho SS, Yong MC, Tie ST
    Med J Malaysia, 2022 Nov;77(6):650-654.
    PMID: 36448380
    INTRODUCTION: Corticosteroids, particularly methylprednisolone, are part of the treatment for severe COVID-19 with acute respiratory distress syndrome (ARDS). In this study, we aimed to compare the mortalities of patients treated with higher versus lower doses of methylprednisolone. Secondary outcomes included oxygenation, need for mechanical ventilation, length of stay in intensive care unit (ICU), secondary infection, improvement of PaO2/FiO2 (PF) ratio, and inflammatory response as expressed by C-reactive protein (CRP).

    MATERIALS AND METHODS: A retrospective cohort study conducted at Sarawak General Hospital from 1st June to 30th September 2021. Patients who received intravenous methylprednisolone for severe COVID-19 in the ICU were identified and divided into two groups: higher dose (cumulative dose more than 10 mg per kg) and lower dose (cumulative dose less than 10 mg per kg).

    RESULTS: Out of a total of 165 patients, 40 (24.2%) patients received higher dose methylprednisolone. There was no significant difference in socio-demographic characteristics (age, gender, body mass index), COVID-19 vaccination status, laboratory parameters (lymphocyte count, CRP, lactate dehydrogenase, D-dimer), or usage of immunomodulator therapy between the groups. Overall mortality was 23.6%. Mortality in the higher dose group was twice as high compared to lower dose group (37.5% versus 19.2%) (OR 3.79, 95% CI 1.24-11.59, p<0.05). In addition, the higher dose cohort developed more secondary infections (87.5%) and had longer stays in ICU (median 11 days, IQR 8- 15). No significant difference was found between both cohorts in terms of CRP reduction, improvement of PF ratio, or the need for mechanical ventilation post methylprednisolone.

    CONCLUSION: In this study, the use of higher dose methylprednisolone in COVID-19 with ARDS was not associated with better clinical outcomes. A lower dose of methylprednisolone might be sufficient in treating severe COVID-19 with ARDS.

  9. Loh HH, Lim QH, Chai CS, Goh SL, Lim LL, Yee A, et al.
    J Sleep Res, 2023 Feb;32(1):e13726.
    PMID: 36104933 DOI: 10.1111/jsr.13726
    Obstructive sleep apnea is a chronic, sleep-related breathing disorder, which is an independent risk factor for cardiovascular disease. The renin-angiotensin-aldosterone system regulates salt and water homeostasis, blood pressure, and cardiovascular remodelling. Elevated aldosterone levels are associated with excess morbidity and mortality. We aimed to analyse the influence and implications of renin-angiotensin-aldosterone system derangement in individuals with and without obstructive sleep apnea. We pooled data from 20 relevant studies involving 2828 participants (1554 with obstructive sleep apnea, 1274 without obstructive sleep apnea). The study outcomes were the levels of renin-angiotensin-aldosterone system hormones, blood pressure and heart rate. Patients with obstructive sleep apnea had higher levels of plasma renin activity (pooled wmd+ 0.25 [95% confidence interval 0.04-0.46], p = 0.0219), plasma aldosterone (pooled wmd+ 30.79 [95% confidence interval 1.05-60.53], p = 0.0424), angiotensin II (pooled wmd+ 5.19 [95% confidence interval 3.11-7.27], p 
  10. Kho SS, Nyanti LE, Chai CS, Kho SK, Ismail AM, Voon PJ, et al.
    Respir Investig, 2023 Jul;61(4):473-477.
    PMID: 37182371 DOI: 10.1016/j.resinv.2023.04.003
    Peripheral transbronchial needle aspiration (pTBNA) allows the access of pulmonary nodules without bronchus sign but is limited to cytological examination. A 39-year-old man with left parotid carcinoma presented with an incidental lung nodule. Target localisation was performed with manual airway mapping, virtual bronchoscopic navigation, and pTBNA. Direct target validation using radial endobronchial ultrasound (rEBUS) was performed through the puncture defect. Targeted pinpoint biopsy with a 1.1 mm cryoprobe through the pTBNA puncture defect confirmed metastatic adenoid cystic carcinoma. Guided pTBNA with rEBUS validation followed by cryobiopsy of lung nodules without bronchus sign is potentially feasible for histological and molecular analyses.
  11. Chai CS, Chan SK, Kho SS, Ahmad A, Tie ST
    J Bronchology Interv Pulmonol, 2023 Jul 01;30(3):285-288.
    PMID: 37101325 DOI: 10.1097/LBR.0000000000000922
  12. Poh ME, Ampikaipakan S, Liam CK, Chai CS, Ramanaidoo D, Haja Mydin H
    J Asthma Allergy, 2021;14:629-640.
    PMID: 34140782 DOI: 10.2147/JAA.S309143
    BACKGROUND: There have been limited reports looking into the care of patients with asthma exacerbations admitted to tertiary hospitals in Southeast Asia. This study aims to determine the extent in which the 2019 Global Initiative for Asthma (GINA) guidelines were being met.

    METHODS: A retrospective study of patients with asthma exacerbations admitted to the University of Malaya Medical Centre (UMMC) and Pantai Hospital Kuala Lumpur (PHKL), Malaysia from 1 July 2019 to 31 December 2019.

    RESULTS: There were significant numbers of patients with previous admissions for asthma in both centres, with almost 50% experiencing an exacerbation in the previous year. Approximately 75% of the patients considered their asthma to be controlled when asked, despite many of them having had a history of acute exacerbations in the previous year. When cross-checked, the level of GINA-defined asthma control remained low, with only 6.4% of the patients deemed to have good control, while asthma was partially controlled in 25.6% of the patients and uncontrolled in 68% of the patients. About 72.1% of the patients reported daytime symptoms, 65.1% of the patients reported night-time symptoms, 70.9% of the patients required frequent usage of rescue inhalers and 72.1% of the patients reported some limitation in their activity prior to the current asthma exacerbation. Almost a quarter of the patients who were admitted had severe or life-threatening exacerbations as defined by GINA. These patients had more hospitalizations in a year and were more likely to have previous admissions requiring non-invasive and invasive ventilation. They were also more likely to be on GINA Step 5 treatment, had a lower mean percent predicted FEV1 and a higher baseline blood eosinophil count. Multivariate analysis revealed that baseline eosinophil count were independently associated with severe or life-threatening asthma exacerbations (odds ratio: 1.01, 95% confidence interval: 1.00-1.01, p=0.001). Failure to adhere to daily controller medications was high in this study (37.2%).

    CONCLUSION: Although the management of asthma exacerbations in tertiary hospitals in Southeast Asia is largely congruous with international guidelines, there is room for improvement. As there is a marked discrepancy between patient-perceived and guideline-defined asthma control, efforts to increase awareness on the dangers of uncontrolled asthma are warranted.

  13. Kho SS, Chai CS, Ho RL, Yong MC, Chan SK, Tie ST
    J Bronchology Interv Pulmonol, 2024 Jan 01;31(1):90-92.
    PMID: 37735753 DOI: 10.1097/LBR.0000000000000946
  14. Kho SS, Chai CS, Nyanti LE, Ismail AMB, Tie ST
    BMC Pulm Med, 2020 Jun 03;20(1):158.
    PMID: 32493437 DOI: 10.1186/s12890-020-01199-3
    BACKGROUND: Lung cancer is frequently situated peripherally in the upper lobes of the lung. Acquiring adequate tissue from this difficult-to-reach area remains a challenge. Transbronchial cryobiopsy (TBCB) has the ability to acquire larger specimens, but the rigidity of the standard 1.9 mm and 2.4 mm cryoprobes frequently poses challenges when used with a guide sheath (GS). The novel 1.1 mm cryoprobe, being both smaller and more flexible, may address this limitation. We describe the usage of this 1.1 mm flexible cryoprobe with GS in the biopsy of solitary pulmonary nodules (SPN) in the apical segment of the upper lobe in two cases.

    CASE REPORT: Both procedures were conducted with advanced airway under total intravenous anaesthesia. 2.6 mm GS was used in combination with a 2.2 mm rEBUS probe, using a therapeutic bronchoscope. Case 1 describes a SPN in the apical segment of the right upper lobe that was inconclusive by forceps biopsy due to GS displacement and inadequate biopsy depth. A steerable GS combined with the novel cryoprobe subsequently overcame this issue. Case 2 describes a SPN in the apical segment of the left upper lobe in which the standard cryoprobe failed to advance through the GS due to steep angulation. It also highlights with shorter activation time, the novel cryoprobe enable biopsied tissue to be retrieved through the GS while the bronchoscope-GS remains wedgend in the airway segment. There were no bleeding or pneumothorax complications in both cases, and histopathological examination confirmed adenocarcinoma of the lung.

    CONCLUSION: The 1.1 mm flexible cryoprobe in combination with GS and therapeutic bronchoscope offers an option to acquire adequate tissue in difficult-to-reach regions in the lung such as the apical segment of upper lobes. Further prospective series to evaluate its performance and safety in SPN biopsy is highly anticipated.

  15. Chai CS, Chan SK, Kho SS, Yong MC, Tie ST
    Respirol Case Rep, 2020 Jul;8(5):e00562.
    PMID: 32313656 DOI: 10.1002/rcr2.562
    Bronchopleural fistula (BPF) can complicate necrotizing pneumonia. Surgery would be indicated in patients who fail conservative management, yet this group is often of poor pulmonary function and general condition. Bronchial occlusion with endobronchial Watanabe spigots (EWS) can be a potential alternative treatment when the culprit bronchi can be isolated. In this case report, we describe a middle-aged gentleman who presented with necrotizing pneumonia complicated with pyopneumothorax with right upper lobe BPF, and who had failed to respond to chest drainage and antibiotics. EWS bronchial occlusion finally led to cessation of air leak, allowing removal of chest tube. EWS were removed uneventfully six months later. This case highlights the role of EWS in the management of BPF in patients with high surgical risk.
  16. Ng DL, Malik NMBA, Chai CS, Goh GM, Tan SB, Bee PC, et al.
    Health Qual Life Outcomes, 2020 Oct 20;18(1):347.
    PMID: 33081816 DOI: 10.1186/s12955-020-01600-z
    BACKGROUND: The use of warfarin in patients with non-valvular atrial fibrillation (NVAF) can be challenging. In this study, we evaluate the time in therapeutic range (TTR), health-related quality of life (HRQoL) and treatment satisfaction of patients on long-term warfarin for NVAF. The HRQoL and treatment satisfaction were compared based on the TTR.

    METHODS: A cross-sectional study was conducted among patients on warfarin for NVAF who attended the anticoagulant clinic of a tertiary cardiology referral center in Sarawak from 1st June 2018 to 31st May 2019. Patients' TTR was calculated by using Rosendaal technique, while their HRQoL and treatment satisfaction were assessed by using Short Form 12 Health Survey version 2 (SF12v2) and Duke Anticoagulant Satisfaction Scale (DASS), respectively.

    RESULTS: A total of 300 patients were included, with mean TTR score of 47.0 ± 17.3%. The physical component summary (PCS) and mental component summary (MCS) score of SF-12v2 were 47.0 ± 9.0 and 53.5 ± 9.6, respectively. The total score for DASS was 55.2 ± 21.3, while the score for limitations (L), hassles and burdens (H&B) and positive psychological impacts (PPI) were 18.0 ± 10.0, 15.6 ± 9.1 and 21.6 ± 5.9, respectively. Seventy-three (24.3%) patients had good TTR (≥ 60%), with mean of 70.2 ± 8.7%; while 227 (75.5%) patients with poor TTR had significantly lower mean of 39.5 ± 11.9% (p = 0.006). There was no significant difference in the score of PCS (p = 0.150), MCS (p = 0.919) and each domain of SF-12v2 (p = 0.184-0.684) between good and poor TTR, except for social functioning (p = 0.019). The total DASS score was also not significantly different between group (p = 0.779). Similar non-significant difference was also reported in all the DASS sub dimensions (p = 0.502-0.699).

    CONCLUSIONS: Majority of the patients on long-term warfarin for NVAF in the current study have poor TTR. Their HRQoL and treatment satisfaction are independent of their TTR. Achieving a good TTR do not compromise the HRQoL and treatment satisfaction. Therefore, appropriate measures should be taken to optimise INR control, failing which direct oral anticoagulant therapy should be considered.

  17. Poh ME, Liam CK, Mun KS, Chai CS, Wong CK, Tan JL, et al.
    Thorac Cancer, 2019 09;10(9):1841-1845.
    PMID: 31350945 DOI: 10.1111/1759-7714.13156
    Adjuvant chemotherapy has long been indicated to extend survival in completely resected stage IB to IIIA non-small cell lung cancer (NSCLC). However, there is accumulating evidence that chemotherapy or chemoradiotherapy can induce epithelial-to-mesenchymal transition (EMT) in disseminated or circulating NSCLC cells. Here, we describe the first case of EMT as the cause of recurrence and metastasis in a patient with resected stage IIB lung adenosquamous carcinoma after adjuvant chemotherapy. We review the literature and explore the possible mechanisms by which EMT occurs in disseminated tumor cells (DTC) or circulating tumor cells (CTC) in response to adjuvant chemotherapy (cisplatin) as a stressor. We also explore the possible therapeutic strategies to reverse EMT in patients with recurrence. In summary, although adjuvant cisplatin-based chemotherapy in resected NSCLC does extend survival, it may lead to the adverse phenomenon of EMT in disseminated tumor cells (DTC) or circulating tumor cells (CTC) causing recurrence and metastasis.
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