Papers by Dr C Sivathasan
The Journal of Heart and Lung Transplantation
Annals of the Academy of Medicine, Singapore, 1991
The current techniques of donor procurement and transplantation provide a very low incidence &quo... more The current techniques of donor procurement and transplantation provide a very low incidence "of non rejection graft failure", following cardiac transplantation. Attention needs to be paid to the preservation of organ function in the potential donor, in order to maximise the donor availability in an environment of perpetual donor shortage. The strategies aimed at myocardial preservation in the donor will be methods of protection from the pathophysiological changes associated with onset of cerebral injury and brain death. The role of various types of cardioplegia, additives and preservation fluids need to be investigated to minimise the effects of cardiac ischaemia and reperfusion injury. There is evidence to suggest the improvement in long term survival with tissue matching in cardiac transplantation. This will need methods of prolonging safe ischaemic time for the donor heart so that tissue matching and organ sharing can be carried out.
The Journal of Heart and Lung Transplantation
Singapore medical journal, 1997
Rupture of the aortic sinus of Valsalva is one of the rare causes of acute dyspnoea. Modern advan... more Rupture of the aortic sinus of Valsalva is one of the rare causes of acute dyspnoea. Modern advances have enabled diagnosis to be made easily with echocardiography as illustrated in this case. The treatment of choice is surgery with excellent prognosis if detected early. Therefore a high index of suspicion is required to diagnose this potentially threatening but yet treatable condition.
The Journal of Heart and Lung Transplantation, 2021
Purpose The incidence of driveline fractures among patients on HeartMate II Left Ventricular Assi... more Purpose The incidence of driveline fractures among patients on HeartMate II Left Ventricular Assist Device (LVAD) support is reviewed Methods This is a single-center, retrospective review of all the patients on HeartMate II LVAD support who presented with driveline fractures. Patients’ presentation, interventions, and outcome following corrective treatment were examined. Results Between May 2009 and October 2018, 60 HeartMate II LVAD were implanted. Over a cumulative support period of 81 patient-years (maximum, 8.5 years), 15 patients (25%) had driveline fractures (age 14-70, 2 female), 5 of them were destination therapy (> 65 years old). Mean duration from the time of implant to driveline fractures was 44.5 ± 15.5 months. 12 patients had significant weight gain following LVAD implant, ranging from 5.2 to 32.3kg (median 17.4kg). While tethered on to power module, 8 patients (53.3%) encountered intermittent pump stoppage, 5 (33.3%) had transient low pump speed, 1 (6.7%) had recurrent driveline fault and 1 more (6.7%) presented with hemoserous discharge leaking from broken insulation in the external driveline with multiple recurrent low voltage advisory. Ungrounded cable was issued to 13 patients as a temporary measure with mean duration of its usage of 259 days (range 26-980 days), before corrective treatment. There were 2 patients with ongoing use of the ungrounded cable (mean 1 year). 8 patients (53.3%) underwent pump replacement, 2 with significant external driveline fractures successfully underwent external driveline replacement and 1 underwent heart transplant. Of the 9 pumps returned for analysis, 7 (78%) were found to have damaged internalized part of the driveline while 2 (22%) had circumferential fractures at the edge of the pump housing extending across the diameter of the bend relief. There were 3 mortality (20%), 1 due to recurrent pump pocket infection and pump thrombosis following the initial pump replacement for driveline fractures, 1 died of subdural haemorrhage before elective pump exchange and 1 died 3 weeks after pump stoppage. Conclusion The incidence of HeartMate II internal driveline fractures seemed to be higher in our Asian experience as opposed to what have been reported in literature. An ungrounded cable served as a temporary measure for short to shield and a timely pump exchange maybe lifesaving when driveline damage progressed into phase to phase.
The Journal of Thoracic and Cardiovascular Surgery, 1987
A case of acute valve thrombosis occurring in a Starr-Edwards aortic prosthesis during the immedi... more A case of acute valve thrombosis occurring in a Starr-Edwards aortic prosthesis during the immediate postoperative period is reported. This appears to be the first such case to be reported. Acute thrombosis occurring in a Starr-Edwards aortic prosthesis during the immediate postoperative period has not been previously reported in the English literature. Such a complication occurring during the first 6 hours after aortic valve replacement is described in the following case report. Case report. A 56-year-old man was admitted to the hospital in August 1985 with a history of progressive effort dyspnea of 18 months' duration and paroxysmal nocturnal dyspnea of 4 months' duration.
The Journal of Heart and Lung Transplantation, 2019
The Journal of Heart and Lung Transplantation, 2019
Purpose: Very little is known about frailty in patients with a left ventricular assist device (LV... more Purpose: Very little is known about frailty in patients with a left ventricular assist device (LVAD) in general, and about reversibility of different measures of frailty post LVAD in particularly. The purpose of the study was to determine which measures of frailty improve post LVAD implantation. Methods: This was an observational, longitudinal (3 month) cohort study of 25 patients with advanced heart failure who underwent LVAD implantation between January 2015 and May 2016. Demographic and clinical data were retrieved from hospital medical records. The six minute walk test (6MWT) was conducted by physical therapist and hand grip strength was assessed by a nurse practitioner using a hand dynamometer. Paired t-test was used to determine differences between pre and post 6MWT, handgrip strength and serum albumin levels. Demographic and clinical characteristics were reported using frequencies, percentages for categorical variables and mean § standard deviation for continuous variables. Results: A majority of the patients were male (88%) and over 40% of the patients in the study were under the age of 60. The primary etiology of heart failure for his population was ischemic cardiomyopathy (60%). Complete data were collected on 23 patients. One patient died within 3 months of LVAD implant and one patient was wheelchair bound post LVAD implant. The mean pre-operative albumin level was 2.7 § .4 mg/dL with only 4% of patients having an albumin levels > 3.5 mg/dl. The albumin became normal after surgery (see Table). Only 8% of patients walked 300 feet or more in 6 minutes pre-implant. In contrast 53% were able to walk more than 300 feet at 3 months post-implant. There was no difference in hand grip strength. Conclusion: Albumin levels and 6MWT significantly improved 3 months post LVAD implant, while hand grip strength noted no improvement. Short 6MWT distance and low albumin should not preclude LVAD implant because these measures of frailty are reversible and are likely to improve shortly after surgery. Pre implant and Post implant Frailty Measures Frailty Measure Pre I mplant 3 Months Post Implant p value Hand grip strength 22.8 § 10.7 24.7 § 11.1 .06 Six minute walk (feet) 186 § 83.2 275 § 121.1 <.001 Albumin (mg/dl) 2.7 § .4 3.5 § .4 <.001
The Journal of Heart and Lung Transplantation, 2019
baloon pump preoperatif period. TAPSE was 13.4 §3.2 (7-20) mm, right ventricle FAC was 25 % § 7 (... more baloon pump preoperatif period. TAPSE was 13.4 §3.2 (7-20) mm, right ventricle FAC was 25 % § 7 (10-40). Mean INTERMACS was 2,8 §0,7 (1-4). The average cardiopulmonary bypass durations was 86,5,2 +/-29,7 min (range: 12-141). Peroperative red blood cell transfusion 1.6 § 1.4 (0-5) Unite, early right ventricular failure was 10.1%, mean mechanical ventilation time 2.1 § 2,5 8 1-15 days, intensive care unit length of stay was 7,3 §4,2 (1-16) days. At 443,7 days mean follow up time 82,5% survival was observed. The most common adverse event on device was driveline infection (18,3%). Gastrointestinal bleeding was 2%, hemorrhagic cerebrovascular event was 8%, pump trombosis 10,2%, late right ventricle failure 5%, hemorrhagic cerebrovascular event was 8%. Eleven patients (22,4%) were transplanted. Conclusion: Minimally invasive implantation of left ventricular assist devices both of two pump HeartWar (HVAD) and Heartmate 3 is safely feasible. After a very good initial experience with this technique it has become the method of choice in our department.
The Journal of Heart and Lung Transplantation, 2017
Purpose: Limited data exists describing impact of body mass index (BMI) on post LVAD outcomes. We... more Purpose: Limited data exists describing impact of body mass index (BMI) on post LVAD outcomes. We sought to define the relationship between BMI and adverse events (AE) following LVAD implantation by examining the ISHLT Mechanically Assisted Circulatory Support (IMACS) registry. Methods: Patients implanted with a contemporary continuous flow (CF) LVAD were stratified into 4 groups using pre-operative BMI: underweight (UW) (BMI< = 18.5 kg/m 2), non-obese (NO) (BMI> 18.5 kg/m 2 ,< 30 kg/ m 2), obese (OB) (BMI> = 30 kg/m 2 ,< 40 kg/m 2), and morbidly obese (MO) (BMI> = 40 kg/m 2). Freedom from AE was evaluated using the Kaplan Meier method. A p-value < .05 was significant. AE included infection, thromboembolic events, bleeding, device malfunction, and neurological dysfunction. Results: Between 2013 and 2015, 9,408 pts underwent implantation of a CF-LVAD. 368 (3.9%) pts were UW, 5,719 (60.8%) NO, 2,770 (29.4%) OB, and 444 (4.7%) MO. Infection (37%) and bleeding (33%) were the two most common AE. MO pts were younger (48 vs 57 years old, p< .0001), diabetic (15% vs 10%, p= .0003), and destination therapy (60% vs 41%, p< .0001). Survival amongst the 4 BMI cohorts was similar at 2 years (70.8%-75.8%, p= 0.24). MO pts were less likely to be free from an infection (p< .0001)(Figure) or device related infection (p= .0008) at 2 years (34.7%, 71.9%) when compared to OB (46.2%, 79.2%), NO (52.5%, 81.7%) and UW (54.0%, 77.5%). UW and NO pts were more likely to be free from device malfunction at 2 years (81.3%) when compared to OB (77.8%) and MO (72.2), p= .0003. Thromboembolic events were rare and more common in the UW cohort (p= .026). Conclusion: While BMI was not correlated with 2-year mortality, an increased frequency of infectious and device related AE was noted in OB and MO LVAD patients. In a group with few options for transplant, the event morbidity in obese patients can be expected to impact survival with longer support durations. Studies examining the impact of weight loss and exercise programs designed specifically for LVAD patients are needed.
The Journal of Heart and Lung Transplantation, 2017
and received antibiotics, of which 61 (16%) were readmitted for DLIs and 27 (7%) required surgica... more and received antibiotics, of which 61 (16%) were readmitted for DLIs and 27 (7%) required surgical intervention. The most common pathogens in the surgery group were Pseudomonas Aeruginosa (26%), Methicillin-resistant Staphylococcus aureus (22%) and Methicillin-sensitive Staphylococcus aureus (19%). No individual surgical technique achieved higher rates of healing compared to others. The NPVD group included 90 patients with a follow-up of nearly 12 months. Fifteen patients (17%) were treated for DLIs, of which 7 (7%) required surgical intervention. There was a trend towards reduced total DLIs in the NPVD group (p< .09). Conclusion: DLIs continue to be a challenging and morbid complication, affecting nearly 25% of our patients. Although there was no significant difference in the healing rates between various surgical techniques, it does appear that the application of NPVD at the time of implantation might reduce the incidence of DLIs. Long-term follow-up and increased study size is needed to more fully define the efficacy of this intervention.
The Journal of Heart and Lung Transplantation, 2017
Increasingly Extracorporeal Membrane Oxygenation (ECMO) is being used as a bridge to decision for... more Increasingly Extracorporeal Membrane Oxygenation (ECMO) is being used as a bridge to decision for recovery, transplantation or to a durable left ventricular assist device (LVAD) for patients presenting with cardiogenic shock. We report our outcomes in INTERMACS I patients receiving a durable LVAD after bridging with ECMO. Methods: A retrospective review of 20 consecutive INTERMACS profile I patients who were bridged from ECMO support to continuous-flow LVAD between May 2009 and September 2016 in Singapore was performed in order to evaluate our outcomes based on our management protocol. Results: 16 were males. The aetiologies include acute coronary syndrome in 12 (60%), dilated cardiomyopathy in 4 (23%), myocarditis in 3 (15%) and ischemic cardiomyopathy in 1 (5%). Mean age at the time of LVAD implant was 40 (± 14) years old. The total length of LVAD support was 33 patient months. Twelve patients received HeartMate II LVAD and two received HeartMate III LVAD. Six received HeartWare LVAD. Majority (18, 90%) were BTT while two were DT (10%). Median duration of ECMO support was 10 days (range 1-23). Mean length of hospital stay following LVAD implant was 50 days (range 15-99). There was is no in-hospital mortality. Kaplan Meier survival at 1-year was 100% and 91.7% at 3-years. Following LVAD implantation, four (20%) received cardiac transplant and one (5%) had LVAD explant following myocardial recovery. Conclusion: Our zero peri-operative mortality in this high risk group suggests that our management protocol is valid. The 3-years survival too appears to be favourable compared to INTERMACS registry data.
The Journal of Heart and Lung Transplantation, 2017
seen pathogen was Klebsiella in all groups. The multivariate analysis revealed that ECMO duration... more seen pathogen was Klebsiella in all groups. The multivariate analysis revealed that ECMO duration more than 5 days in adults and age below 2 years in pediatric group were found to be as significant risk factors for infection (Table 3). Conclusion: Determination of risk factors will play important role in ECMO infection prevention. It seems that age below 2 years old and support longer than 5 days will increase the risk for infections. Special precautions should be taken in these patient groups.
The Journal of Heart and Lung Transplantation, 2015
The Journal of Heart and Lung Transplantation, 2015
Purpose: Cardiac resynchronization therapy (CRT) reduces ventricular arrhythmia (VA) burden and h... more Purpose: Cardiac resynchronization therapy (CRT) reduces ventricular arrhythmia (VA) burden and hospitalizations in some patients who have heart failure with reduced ejection fraction. The role of CRT in patients with left ventricular assist devices (LVAD) is unknown. We sought to determine whether continued biventricular (BiV) pacing after LVAD implantation reduced VA burden, implantable cardioverter-defibrillator (ICD) shocks, or hospitalizations for any cause. Methods: We conducted a retrospective analysis of 93 patients who were implanted with LVADs at a single center. Patients were grouped according to whether they received BiV pacing for 30 days or more after LVAD implantation (n= 39) or less than 30 days of BiV pacing (n= 54). The total number of sustained VA, ICD shocks, hospitalizations, and device related surgical interventions were compared between the two groups until death or heart transplantation. Results: Patients with BiV pacing 30 days or more after LVAD implantation had similar time to first VA, time to first ICD shock, or hospitalization for any cause compared to patients with less than 30 days of BiV pacing. There was a trend toward earlier VA and ICD shocks in patients who were BiV paced 30 days or more, even if VA events during the first 30 days after LVAD implantation were excluded. There were no statistically significant differences in LVAD pump exchanges or mean ICD pulse generator changes per patient between groups. Multivariate logistic regression analysis showed that VA after LVAD implantation was best predicted by VA prior to LVAD implantation, but did not correlate with continuation of CRT. Conclusion: In this study CRT after LVAD implantation does not appear to reduce VA burden, ICD shocks, or hospitalizations for any cause. There appeared to be no clinical detriment in patients where CRT was discontinued.
Asian cardiovascular & thoracic annals, Jan 27, 2014
Thoratec recalled their HeartMate II ventricular assist device in March 2012 after some problems ... more Thoratec recalled their HeartMate II ventricular assist device in March 2012 after some problems related to disconnection of the bend relief. Abrasion on the pump outflow graft caused by a disconnected bend relief is rare. We report the case of a 49-year-old man in whom a disconnected bend relief caused a puncture in the outflow graft, resulting in a contained hematoma, requiring outflow graft replacement.
The Ceylon medical journal
Annals of the Academy of Medicine, Singapore, 1987
The purpose of this study was to analyse the pattern of benign mediastinal teratoma, in this regi... more The purpose of this study was to analyse the pattern of benign mediastinal teratoma, in this region. The paper is based on a retrospective analysis of 16 consecutive patients who were admitted to the Cardiothoracic Surgical unit in Singapore from 1967 through 1984. The disease pattern appears to be similar to those reported from the west. Complete surgical excision offers a cure and it can be carried out safely.
Annals of the Academy of Medicine, Singapore, 1988
104 patients who had prosthetic valve replacements were followed up for a period from 5 months to... more 104 patients who had prosthetic valve replacements were followed up for a period from 5 months to 63 months. The incidence of minor and major thromboembolism for aortic valve replacement was 1.2%/Pt.yr respectively, while the incidence for mitral valve replacement was 3.8%/Pt.yr. respectively. The haemorrhagic complication rate due to anticoagulation was 3.7%/Pt.yr. and the fatality rate due to it was 1.4%/Pt.yr. 75% of the patients who had haemorrhagic complications had a thrombotest of less than 4%. Anticoagulation related morbidity and mortality are significant in this series. Elimination of anticoagulation related complications could have improved the long term mortality rate from 2.95%/Pt.yr. to 1.4%/Pt.yr.
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Papers by Dr C Sivathasan