Displaying publications 1 - 20 of 29 in total

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  1. Saram SJ, Leong MC, Sivalingam S
    Interact Cardiovasc Thorac Surg, 2021 10 04;33(4):671.
    PMID: 34606583 DOI: 10.1093/icvts/ivab129
    Matched MeSH terms: Heart Valve Prosthesis*
  2. Fallahiarezoudar E, Ahmadipourroudposht M, Idris A, Mohd Yusof N
    Mater Sci Eng C Mater Biol Appl, 2015 Mar;48:556-65.
    PMID: 25579957 DOI: 10.1016/j.msec.2014.12.016
    The four heart valves represented in the mammalian hearts are responsible for maintaining unidirectional, non-hinder blood flow. The heart valve leaflets synchronically open and close approximately 4 million times a year and more than 3 billion times during the life. Valvular heart dysfunction is a significant cause of morbidity and mortality around the world. When one of the valves malfunctions, the medical choice is may be to replace the original valves with an artificial one. Currently, the mechanical and biological artificial valves are clinically used with some drawbacks. Tissue engineering heart valve concept represents a new technique to enhance the current model. In tissue engineering method, a three-dimensional scaffold is fabricated as the template for neo-tissue development. Appropriate cells are seeded to the matrix in vitro. Various approaches have been investigated either in scaffold biomaterials and fabrication techniques or cell source and cultivation methods. The available results of ongoing experiments indicate a promising future in this area (particularly in combination of bone marrow stem cells with synthetic scaffold), which can eliminate the need for lifelong anti-coagulation medication, durability and reoperation problems.
    Matched MeSH terms: Heart Valve Prosthesis*
  3. Soo CS, Ca M, Tay M, Yeoh JK, Sim E, Choo M
    J Am Soc Echocardiogr, 1994 3 1;7(2):159-64.
    PMID: 8185960
    We prospectively studied 37 consecutive patients implanted with the Carbomedics prosthetic heart value in the mitral position (without clinical evidence of prosthetic valve dysfunction) with two-dimensional and Doppler echocardiography. The peak mitral prosthetic gradient ranged from 4.60 to 14.63 (mean 8.97 +/- 2.29) mm Hg; mean mitral prosthetic gradient ranged from 1.67 to 6.18 (mean 3.24 +/- 0.95) mm Hg; pressure half-time derived mitral valve area ranged from 1.67 to 5.30 (mean 2.70 +/- 0.80) cm2. These values compare favorably with that of another bileaflet valve (i.e., the St. Jude Medical valve). There was a wide overlap in peak and mean transmitral gradients, even with the valves of the same size, with a significant but weak inverse relationship between peak mitral gradients and valve size (p = 0.03, r = -0.36). The performance index showed a smaller range of values, again with a significant but weak inverse relationship with valve size (p = 0.001, r = -0.54). The inverse relationship between valve size and peak mitral gradient and performance index should be borne in mind when analyzing Doppler hemodynamic data.
    Matched MeSH terms: Heart Valve Prosthesis*
  4. Ooi, Ching Sheng, Lim, Meng Hee, Lee, Kee Quen, Kang, Hooi Siang, Mohd Salman Leong
    MyJurnal
    Previous studies have indicated that the pipe-surface-mounted helical strakes effectively reduce vortex-induced vibration (VIV) under a uniform flow application, particularly during the lock-in region. Since VIV experiments are time-consuming, observation is generated with an interval helical strakes parameter in pitch and height to lessen tedious procedures and repetitive post-processing analyses. The aforementioned result subset is insufficient for helical strakes design optimisation because the trade-off between the helical strakes dimension, lock-in region and flow velocity are non-trivial. Thus, a parametric model based on an improved recursive least squares (RLS) parameter estimation technique is proposed to define the statistical relationship between input, or strakes and pipe dimension, and output, or VIV amplitude ratio. As results suggested, revised RLS estimated VIV model demonstrated an optimal prediction with the highest coefficient of determination and lowest Integral Absolute Error. The feasibility of VIV parametric model was validated by embed into Genetic Algorithm (GA) as the fitness function to acquire a desirable helical strakes dimension with minimum VIV amplitude. The rapid generation of optimal helical strakes dimension which returned the highest VIV suppression implied a superior simulation method compared to the experimental outcome.
    Matched MeSH terms: Heart Valve Prosthesis
  5. Abbas SS, Nasif MS, Al-Waked R, Meor Said MA
    Artif Organs, 2020 Feb;44(2):E20-E39.
    PMID: 31378963 DOI: 10.1111/aor.13536
    Platelet activation induced by shear stresses and non-physiological flow field generated by bileaflet mechanical heart valves (BMHVs) leads to thromboembolism, which can cause fatal consequences. One of the causes of platelet activation could be intermittent regurgitation, which arises due to asynchronous movement and rebound of BMHV leaflets during the valve closing phase. In this numerical study, the effect of intermittent regurgitation on the platelet activation potential of BMHVs was quantified by modeling a BMHV in the straight and anatomic aorta at implantation tilt angles 0°, 5°, 10°, and 20°. A fully implicit Arbitrary Lagrangian-Eulerian-based Fluid-Structure Interaction formulation was adopted with blood modeled as a multiphase, non-Newtonian fluid. Results showed that the intermittent regurgitation and consequently the platelet activation level increases with the increasing implantation tilt of BMHV. For the straight aorta, the leaflet of the 20° tilted BMHV underwent a rebound of approximately 20° after initially closing, whereas the leaflet of the 10°, 5°, and 0° tilted BMHVs underwent a rebound of 8.5°, 3°, and 0°, respectively. For the anatomic aorta, the leaflet of the 20° tilted BMHV underwent a rebound of approximately 24° after initially closing, whereas the leaflet of the 10°, 5°, and 0° tilted BMHVs underwent a rebound of 14°, 10°, and 7°, respectively. For all the implantation orientations of BMHVs, intermittent regurgitation and platelet activation were always higher in the anatomic aorta than in the straight aorta. The study concludes that the pivot axis of BMHV must be implanted parallel to the aortic root's curvature to minimize intermittent regurgitation and platelet activation.
    Matched MeSH terms: Heart Valve Prosthesis*; Heart Valve Prosthesis Implantation/adverse effects; Heart Valve Prosthesis Implantation/instrumentation*
  6. Riahi M, Ang HL, Jones M, Prachasilchai P, Baruteau AE, Promphan W, et al.
    Circ Cardiovasc Interv, 2018 04;11(4):e005923.
    PMID: 29618579 DOI: 10.1161/CIRCINTERVENTIONS.117.005923
    Matched MeSH terms: Heart Valve Prosthesis*; Heart Valve Prosthesis Implantation/adverse effects; Heart Valve Prosthesis Implantation/instrumentation*; Heart Valve Prosthesis Implantation/methods
  7. Yakub MA, Dillon J, Krishna Moorthy PS, Pau KK, Nordin MN
    Eur J Cardiothorac Surg, 2013 Oct;44(4):673-81.
    PMID: 23447474 DOI: 10.1093/ejcts/ezt093
    Contemporary experience with mitral valve (MV) repair in the rheumatic population is limited. We aimed to examine the long-term outcomes of rheumatic MV repair, to identify the predictors of durability and to compare the repair for rheumatic and degenerative MVs.
    Matched MeSH terms: Heart Valve Prosthesis; Heart Valve Prosthesis Implantation/adverse effects; Heart Valve Prosthesis Implantation/methods*
  8. Yakub MA, Sivalingam S, Dillon J, Matsuhama M, Latiff HA, Ramli MF
    Ann Thorac Surg, 2015 Mar;99(3):884-90; discussion 890.
    PMID: 25579160 DOI: 10.1016/j.athoracsur.2014.09.016
    This study compares the midterm results of mitral valve repair using the biodegradable ring versus repair with non-ring annuloplasty techniques for congenital mitral valve disease in young children where it was not possible to use standard commercial rings.
    Matched MeSH terms: Heart Valve Prosthesis*
  9. Izham IN, Zamrin DM, Joanna OS, Ramzisham AR, Hairolfaizi H, Ishamuddin IM, et al.
    Clin Ter, 2011;162(6):521-5.
    PMID: 22262321
    The effect of the duration of ischaemic myocardial time to left ventricular ejection fraction (LVEF) after valve replacement surgery has been attributed. This study aims to look at the correlation between myocardial ischaemic time and changes LVEF post valve replacement surgery up to 6 months period.
    Matched MeSH terms: Heart Valve Prosthesis Implantation*
  10. Loch A, Sadiq MA, Wan Ahmad WA
    Eur Heart J, 2013 Apr;34(13):981.
    PMID: 23391585 DOI: 10.1093/eurheartj/eht021
    Matched MeSH terms: Heart Valve Prosthesis*
  11. Pau KK, Yakub A, Sallehuddin A, Awang Y
    Med J Malaysia, 2001 Jun;56(2):196-200.
    PMID: 11771080
    From 1982 till 1999, our department performed a total of 2970 heart valve replacements--92% of which were with mechanical heart valves. During this period, there were 8 patients who came to our department with mechanical heart valve obstruction. All these patients presented with signs of heart failure or compromised haemodynamic. Confirmatory tests included transthoracic or transoesophageal echocardiography and cine fluoroscopy. Seven patients were operated upon urgently. Four of the patients had valve thrombosis. The time interval between the initial implantation and presentation varies from 4 months to 11.3 years. Six of the seven patients who were operated on recovered well from the surgery.
    Matched MeSH terms: Heart Valve Prosthesis*
  12. Le Ho Y, Ahmad Zaidi NA, Salleh A, Abdul Kareem BA
    J Cardiothorac Surg, 2021 Apr 17;16(1):92.
    PMID: 33865405 DOI: 10.1186/s13019-021-01458-2
    BACKGROUND: Antiphospholipid syndrome is an antibody mediated pro-thrombotic state leading to various arterial and venous thromboses. The syndrome can be either primary or secondary to other autoimmune diseases, commonly systemic lupus erythematosus. Cardiac involvement, in particular valvular disease is common in patients with antiphospholipid syndrome, occurring in about a third of these patients. Valvular diseases associated with antiphospholipid syndrome often occur as valve thickening and non-bacterial vegetation or Libman-Sacks endocarditis. Deposits of antiphospholipid immunoglobulin and complement components are commonly observed in the affected valves, suggesting an inflammatory process resulting in valvular vegetation and thickening. Libman-Sacks endocarditis has a high propensity towards mitral valve, although haemodynamically significant valvular dysfunction is rare.

    CASE PRESENTATION: We present a successful aortic valve replacement with cardiopulmonary bypass in a 48 years old lady with antiphospholipid syndrome, who has severe aortic regurgitation as a result of Libman-sacks endocarditis. Antiphospholipid antibodies were positive and the clinical data showed both negative cultures and infective parameters. Surgically resected vegetations revealed sterile fibrinous and verrucous vegetations on aortic valve. Valve replacement and the course of cardiopulmonary bypass was uneventful, and the patient was discharged well.

    CONCLUSIONS: Classically Libman-Sacks endocarditis is often and more commonly associated with autoimmune diseases such as systemic lupus erythematosus, although it can occur in both primary and secondary antiphospholipid syndrome. It is not a common entity, and it is a frequent underestimated disease as most clinicians do not routinely screen for valvular lesion in patients with antiphospholipid syndrome unless they are symptomatic. However, due to its high prevalence of cardiac involvement, clinicians should have a high index of suspicion in the attempt to minimize cardiovascular and haemodynamic complications. Valve surgery in patients with antiphospholipid syndrome carries considerable early and late morbidity and mortality, usually caused by thromboembolic and bleeding events. The perioperative anticoagulation management and haemostatic aspect of antiphospholipid syndrome present an exceptional challenges to clinicians, surgeons, anaesthetists and laboratory personnel.

    Matched MeSH terms: Heart Valve Prosthesis Implantation*
  13. Nagandla K, Jamli MFBM, Hanim F, Xu Mei JL, Din SFS
    Pan Afr Med J, 2021;40:52.
    PMID: 34795832 DOI: 10.11604/pamj.2021.40.52.30961
    The common gynaecological causes of acute pelvic pain include ruptured ectopic pregnancy, haemorrhagic corpus luteal cyst or torsion of an ovarian cyst. Ovarian vascular accidents are reported in women on oral anticoagulation presenting as an acute pelvic pain. Although such vascular accidents with anticoagulation therapy are an unusual entity, a meticulous history, clinical examination, and laboratory workup to confirm the diagnosis and timely intervention is needed to reduce attending morbidity and mortality. However, a standard algorithm for management is not described in the literature. We hereby report successful management of recurrent hemorrhagic ovarian cyst due to coagulopathy in a woman with mechanical heart valves with timely surgical intervention. This case report discusses operative versus non operative management approach and may provide value addition to readers encountering such cases in their clinical practice.
    Matched MeSH terms: Heart Valve Prosthesis*
  14. Lim KO, Cheong KC
    Med Eng Phys, 1994 Nov;16(6):526-30.
    PMID: 7858787
    In the fabrication of a bioprosthetic heart valve from bovine pericardial tissues, the tissues are subjected to suturing. The stress-strain response of sutured as well as unsutured strips of this tissue were examined. The stress-strain response was determined using a tensile-testing machine. It was found that suturing weakens the tissue in that sutured strips are more extensible, exhibit a lower stress at rupture and a lower final elastic modulus. In addition, it was also found that the bigger the suture/needle size used the greater the decrease in tissue strength. In all, tissue strength was observed to decrease by 22 to 59% in this study. The weakening of the tissue is attributed to the puncture holes created by the surgeon's needle which create regions of weakness. This response of bovine pericardial tissue to suturing should be given due consideration in the fabrication of a bioprosthetic heart valve using this tissue.
    Matched MeSH terms: Heart Valve Prosthesis/standards*
  15. Vijayan V, Rachel T
    Med J Malaysia, 2012 Dec;67(6):591-4.
    PMID: 23770951 MyJurnal
    The anticoagulation of choice for mechanical heart valves is the oral anticoagulant warfarin. Warfarin is associated with increased risk of miscarriage, intrauterine fetal deaths and warfarin embryopathy. This longitudical cross-over study of 5 women observed all 5 having livebirths of healthy infants after heparin-managed pregnancies. Their earlier 8 pregnancies had all resulted in perinatal losses or miscarriages when on regimes based on warfarin.
    Matched MeSH terms: Heart Valve Prosthesis
  16. Krishnasamy S, Sivalingam S, Dillon J, Mokhtar RAR, Yakub A, Singh R
    PMID: 33577258 DOI: 10.21470/1678-9741-2020-0207
    INTRODUCTION: The presence of aortic regurgitation (AR) in the setting of ventricular septal defect (VSD) has always been a management challenge.

    METHODS: This is a retrospective study looking at patients who underwent VSD closure with or without aortic valve intervention between January 1st, 1992 and December 31st, 2014 at the Institute Jantung Negara. This study looked at all cases of VSD and AR, where AR was classified as mild, moderate, and severe, the intervention done in each of this grade, and the durability of that intervention. The interventions were classified as no intervention (NI), aortic valve repair (AVr), and aortic valve replacement (AVR).

    RESULTS: A total of 261 patients were recruited into this study. Based on the various grades of AR, 105 patients had intervention to their aortic valve during VSD closure. The rest 156 had NI. All patients were followed up for a mean time of 13.9±3.5 years. Overall freedom from reoperation at 15 years was 82.6% for AVr. Various factors were investigated to decide on intervening on the aortic valve during VSD closure. Among those that were statistically significant were the grade of AR, size of VSD, age at intervention, and number of cusp prolapse.

    CONCLUSION: We can conclude from our study that all moderate and severe AR with small VSD in older patients with more than one cusp prolapse will need intervention to their aortic valve during the closure of VSD.

    Matched MeSH terms: Heart Valve Prosthesis
  17. Ngow, H.A., Wan Khairina, W.M.N.
    MyJurnal
    The normal aortic valve has three leaflets, which are almost equal in size. A bicuspid aortic valve developed as a result of abnormal aortic cusp formation during early embryogenesis. Complications such as valvular stenosis or incompetence are well known. Delayed in identifying the congenital abnormality or the complications may cause morbidity and mortality. We report two cases of congestive cardiac failure as the results of undiagnosed bicuspid aortic valve with severe aortic incompetence. Both young men in their productive age without cardiac risk factors, were unfortunate to present too late. Although one of them was lucky to survive the ordeal, most late presentation ends up gravely. Aortic valve replacement can be offered if early detection is made. Those with severe disease at diagnosis may require a heart transplant.
    Matched MeSH terms: Heart Valve Prosthesis
  18. Zakaria MS, Ismail F, Tamagawa M, Aziz AFA, Wiriadidjaja S, Basri AA, et al.
    Med Biol Eng Comput, 2017 Sep;55(9):1519-1548.
    PMID: 28744828 DOI: 10.1007/s11517-017-1688-9
    Even though the mechanical heart valve (MHV) has been used routinely in clinical practice for over 60 years, the occurrence of serious complications such as blood clotting remains to be elucidated. This paper reviews the progress that has been made over the years in terms of numerical simulation method and the contribution of abnormal flow toward blood clotting from MHVs in the aortic position. It is believed that this review would likely be of interest to some readers in various disciplines, such as engineers, scientists, mathematicians and surgeons, to understand the phenomenon of blood clotting in MHVs through computational fluid dynamics.
    Matched MeSH terms: Heart Valve Prosthesis
  19. Krishna Moorthy PS, Sivalingam S, Dillon J, Kong PK, Yakub MA
    Interact Cardiovasc Thorac Surg, 2019 02 01;28(2):191-198.
    PMID: 30085022 DOI: 10.1093/icvts/ivy234
    OBJECTIVES: Contemporary experience in mitral valve (MV) repair for children with rheumatic heart disease (RHD) is limited, despite the potential advantages of repair over replacement. We reviewed our long-term outcomes of rheumatic MV repair and compared them with the outcomes of MV replacement in children with RHD.

    METHODS: This study is a review of 419 children (≤18 years) with RHD who underwent primary isolated MV surgery between 1992 and 2015, which comprised MV repair (336 patients; 80.2%) and MV replacement (83 patients; 19.8%). The replacement group included mechanical MV replacements (MMVRs) (n = 69 patients; 16.5%) and bioprosthetic MV replacements (n = 14 patients; 3.3%). The mean age with standard deviation at the time of operation was 12.5 ± 3.5 (2-18) years. Mitral regurgitation (MR) was predominant in 390 (93.1%) patients, and 341 (81.4%) patients showed ≥3+ MR. The modified Carpentier reconstructive techniques were used for MV repair.

    RESULTS: Overall early mortality was 1.7% (7 patients). The mean follow-up was 5.6 years (range 0-22.3 years; 94.7% complete). Survival of patients who underwent repair was 93.9% both at 10 and 20 years, which was superior than that of replacement (P 

    Matched MeSH terms: Heart Valve Prosthesis Implantation/methods*
  20. Wong MH, Chee KH, Azman W
    Singapore Med J, 2009 Oct;50(10):e362-4.
    PMID: 19907876
    A 40-year-old Malay woman presented with increasing lethargy, palpitation and shortness of breath, 17 years after a mitral and aortic valve replacement. A Starr-Edwards prosthetic valve replaced the mitral valve, and a Bjork-Shiley prosthetic valve replaced the aortic valve. Biochemical parameters demonstrated intravascular haemolysis, as evidenced by haemoglobin 7.8 g/dL, reticulocyte count 8.4%, lactate dehydrogenase 2,057 IU/L and low haptoglobulin levels (less than 6 mg/dL). Transoesophageal echocardiography revealed a paravalvular leakage over the mitral valve. The haemoglobin levels remained persistently low despite frequent blood transfusions. She successfully underwent a second mitral valve replacement. Her anaemia resolved subsequently.
    Matched MeSH terms: Heart Valve Prosthesis/adverse effects*
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