Long-term mortality after isolated coronary artery bypass grafting and risk factors for mortality.

BACKGROUND: Patients requiring coronary artery bypass grafting (CABG) have multiple co-morbidities which need to be considered in totality when determining surgical risks. The objective of this study is to evaluate short-term and long-term mortality rates of CABG surgery, as well as to identify the most significant risk factors for mortality after isolated CABG. METHODS: All patients with complete dataset who underwent isolated CABG between January 2008 and December 2017 were included. Univariate and multivariate Cox regression was performed to determine the risk factors for all-cause mortality. Classification and regression tree analysis was performed to identify the relative importance of these risk factors. RESULTS: 3,573 patients were included in the study. Overall mortality rate was 25.7%. In-hospital mortality rate was 1.62% overall. 30-day, 1-year, 5-year, 10-year and 14.5-year mortality rates were 1.46%, 2.94%, 9.89%, 22.79% and 36.30% respectively. Factors associated with death after adjustment for other risk factors were older age, lower body mass index (BMI), hypertension, diabetes mellitus, chronic obstructive pulmonary disease, pre-operative renal failure on dialysis, higher last pre-operative creatinine level, lower estimated glomerular filtration rate (eGFR), heart failure, lower left ventricular ejection fraction and New York Heart Association class II, III and IV. Additionally, female gender and logistic EuroSCORE were associated with death on univariate Cox analysis, but not associated with death after adjustment with multivariate Cox analysis. Using CART analysis, the strongest predictor of mortality was pre-operative eGFR < 46.9, followed by logistic EuroSCORE ≥ 2.4. CONCLUSION: Poorer renal function, quantified by a lower eGFR, is the best predictor of post-CABG mortality. Amongst other risk factors, logistic EuroSCORE, age, diabetes and BMI had a relatively greater impact on mortality. Patients with chronic kidney disease stage 3B and above are at highest risk for mortality. We hope these findings heighten awareness to optimise current medical therapy in preserving renal function upon diagnosis of any atherosclerotic disease and risk factors contributing to coronary artery disease.

Waitlisted Transplant Candidates' Attitudes and Concerns Toward Transplantation During COVID-19.

BACKGROUND In solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, coronavirus disease 2019 (COVID-19) can contribute to a severe clinical course and an increased risk of death. Thus, patients awaiting a SOT or HSCT face the dilemma of choosing between a life-saving treatment that presents a significant threat of COVID-19 and the risk of waitlist dropout, progression of disease, or mortality. The lack of established literature on COVID-19 complicates the issue as patients, particularly those with inadequate health literacy, may not have the resources needed to navigate these decisions. MATERIAL AND METHODS We conducted a standardized phone survey of patients awaiting SOT or HSCT to assess the prevalence of inadequate health literacy and attitudes toward transplant during the COVID-19 pandemic. RESULTS Seventy-one patients completed the survey, with a response rate of 84.5%. Regardless of health literacy, most waitlisted candidates recognized that the current pandemic is a serious situation affecting their care and that COVID-19 poses a significant risk to their health. Despite the increased risks, most patients reported they would choose immediate transplantation if there was no foreseeable end to the pandemic, and especially if the medical urgency did not permit further delay. There were no differences in responses across the patient waitlist groups for heart, kidney, liver, and stem cell transplant. CONCLUSIONS These findings can help transplant centers decide how transplantation services should proceed during this pandemic and can be used to educate patients and guide discussions about informed consent for transplant during the COVID-19 pandemic.

Long-term prognosis in patients with end-stage renal disease after coronary artery bypass grafting.

BACKGROUND: Cardiovascular disease is a major cause of morbidity and mortality in patients with end-stage renal disease (ESRD). Coronary artery bypass grafting (CABG) is beneficial in selected patients with ESRD. This study investigates the survival outcomes and prognostic factors in ESRD patients who underwent CABG. METHODS: A retrospective analysis was performed for 149 patients with ESRD who underwent isolated CABG between 2006 and 2015. RESULTS: Mean age was 59.4±8.7 years and 106 patients (71.1%) were male. Operative mortality occurred in 20 patients (13.4%). Overall survival was 81.1%±3.2% at 1 year, 41.5%±4.3% at 5 years and 19.2%±4.2% at 10 years. Median survival was 4.3 years. Multivariable analysis identified age [P=0.001, odds ratio (OR): 1.15 per 1-year increase, 95% confidence interval (CI): 1.06-1.25], preoperative left ventricular ejection fraction (LVEF) (P=0.020, OR: 0.94, 95% CI: 0.89-0.99) and non-elective status of operation (P=0.049, OR: 3.34, 95% CI: 1.00-11.1) as predictors of operative mortality. Cox regression analysis identified age [P<0.001, hazard ratio (HR): 1.05 per 1-year increase, 95% CI: 1.03-1.08], New York Heart Association (NYHA) class III or IV status (P=0.010, HR: 1.75, 95% CI: 1.15-2.67) and the use of a left internal mammary artery (LIMA) to left anterior descending artery (LIMA-LAD) graft (P=0.029, HR: 0.42, 95% CI: 0.19-0.92) as factors influencing long-term survival. CONCLUSIONS: CABG is associated with high operative mortality and poor long-term survival in ESRD patients. Age and NYHA class influenced late survival. LIMA-LAD grafting conferred a long-term survival advantage.

An unusual case of Scedosporium apiospermum fungaemia in an immunocompetent patient with a left ventricular assist device and an implantable cardiac device.

Left ventricular assist device (LVAD)-related infections are a leading cause of morbidity and mortality, with fungal infections being particularly difficult to manage. We report a case of an immunocompetent 39-year-old male with an LVAD and an implantable cardiac device (ICD) who developed fatal Scedosporium apiospermum fungaemia. To the best of our knowledge, this is the first reported case of LVAD-related S. apiospermum fungaemia.

Practical Considerations for Solid Organ Transplantation During the COVID-19 Global Outbreak: The Experience from Singapore.

The current coronavirus disease 2019 (COVID-19) pandemic has not only caused global social disruptions but has also put tremendous strain on healthcare systems worldwide. With all attention and significant effort diverted to containing and managing the COVID-19 outbreak (and understandably so), essential medical services such as transplant services are likely to be affected. Closure of transplant programs in an outbreak caused by a highly transmissible novel pathogen may be inevitable owing to patient safety. Yet program closure is not without harm; patients on the transplant waitlist may die before the program reopens. By adopting a tiered approach based on outbreak disease alert levels, and having hospital guidelines based on the best available evidence, life-saving transplants can still be safely performed. We performed a lung transplant and a liver transplant successfully during the COVID-19 era. We present our guidelines and experience on managing the transplant service as well as the selection and management of donors and recipients. We also discuss clinical dilemmas in the management COVID-19 in the posttransplant recipient.

Response and Operating Room Preparation for the COVID-19 Outbreak: A Perspective From the National Heart Centre in Singapore.

The outbreak of coronavirus disease 2019 (COVID-19), a respiratory disease from a novel coronavirus that was first detected in Wuhan City, Hubei Province, China, is now a public health emergency and pandemic. Singapore, as a major international transportation hub in Asia, has been one of the worst hit countries by the disease. With the advent of local transmission, the authors share their preparation and response planning for the operating room of the National Heart Centre Singapore, the largest cardiothoracic tertiary center in Singapore. Protection of staff and patients, environmental concerns, and other logistic and equipment issues are considered.

Prognostic Factors for Survival After Extracorporeal Membrane Oxygenation for Cardiogenic Shock.

The aim of this study is to examine factors that can predict mortality in patients that have veno-arterial extracorporeal membrane oxygenation (VA-ECMO) instituted for cardiogenic shock. A single-center, retrospective study of 127 patients who underwent VA-ECMO for cardiogenic shock between January 2003 and December 2017 was conducted. Eighty-three (65%) patients survived to weaning or bridging therapy. Complications on VA-ECMO include: hemorrhage (40%), stroke (14%), requirement for dialysis (42%), and limb ischemia (24%). Univariate analysis revealed shorter ECMO duration, higher body mass index, preimplantation creatinine > 100 mmol/l, lower preimplantation serum albumin, and the development of stroke or limb ischemia on ECMO to be significantly associated with mortality while on ECMO. Multivariate analysis by logistic regression found shorter ECMO duration and lower preimplantation serum albumin to be significantly associated with mortality. VA-ECMO is an effective strategy in treating patients with cardiogenic shock and provides a reasonable chance of survival to weaning or bridging to other therapy. Preimplantation hypoalbuminemia, preimplantation serum creatinine > 100 mmol/l, and the development of stroke and limb ischemia while on VA-ECMO are strongly associated with mortality.

Does concurrent use of intra-aortic balloon pumps improve survival in patients with cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was 'Does concurrent use of intra-aortic balloon pump (IABP) improve survival in patients with cardiogenic shock requiring venoarterial extracorporeal membrane oxygenation (VA-ECMO)?'. Altogether 472 papers were found using the reported search, of which 3 level 2 systematic reviews represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. The reported comparative outcomes were mortality, weaning off extracorporeal membrane oxygenation (ECMO), vascular complications and non-vascular complications. One systematic review demonstrated significantly lower in-hospital mortality with concurrent use of IABP and VA-ECMO, while the other 2 studies showed no difference in mortality. One paper reported on the weaning success from ECMO and demonstrated significantly higher weaning success with concurrent IABP usage. Another paper reported on the complications and showed no differences in vascular and non-vascular complications. We conclude that there was no significant improvement in survival with the concurrent use of IABP and VA-ECMO for a cardiogenic shock as compared to the use of VA-ECMO alone. However, the concurrent use of IABP with VA-ECMO improved weaning success from VA-ECMO. The incidence of vascular and non-vascular complications was similar with or without IABP usage.

Staphylococcal driveline infections are the predominant type of left ventricular assist device associated infections in Singapore.

BACKGROUND: Left ventricular assist device (LVAD) associated infections (LVADIs) have substantial morbidity and mortality. We aim to describe the incidence and epidemiology of LVADIs in an Asian cohort. This is currently not well studied. METHODS: We conducted a retrospective review of 52 patients who underwent LVAD implantation from 1 May 2009-31 December 2014 in National Heart Centre Singapore. LVADIs were defined based on definitions proposed by the International Society for Heart and Lung Transplantation. RESULTS: There were 39 males and 13 females. Seventy-three percent had Heartmate II LVAD implant while 27% received Heartware HVAD. Eighty-one percent were implanted as bridge to heart transplantation, 19% as destination therapy. Forty-five episodes of LVADIs occurred in 25 patients. Overall LVADI incidence was 47.5 cases per 100 patient-years. Driveline infections (58%) were the commonest type of LVADI. The commonest causative organisms were coagulase-negative staphylococci (33%), Staphylococcus aureus (31%) and Corynebacterium species (19%). Twelve percent of patients with LVADI required surgical debridement and one patient required pump exchange due to pump pocket infection. All-cause mortality was 13%. CONCLUSIONS: The findings of our study add to the understanding and epidemiology of LVADIs, particularly in the Asian setting. This can contribute to the development of evidence based strategies to prevent and manage LVADIs.

Restrictive mitral valve annuloplasty for chronic ischaemic mitral regurgitation: outcomes of flexible versus semi-rigid rings.

BACKGROUND: Restrictive mitral annuloplasty is the mainstay of surgical correction of chronic ischaemic mitral regurgitation (CIMR). Long-term data on the various types of annuloplasty rings is limited. The aim of this study was to investigate the clinical and echocardiographic outcomes of restrictive mitral annuloplasty in patients with CIMR, comparing the use of flexible versus semi-rigid annuloplasty rings. METHODS: A retrospective review was conducted for 133 patients with CIMR who underwent restrictive mitral annuloplasty at our institution between 1999 and 2015. Patient demographics and postoperative outcomes were analyzed. RESULTS: Mean age was 61.9±9.2 years and 103 patients (77.4%) were male. All patients underwent coronary artery bypass grafting, with a mean of 3.3±0.8 grafts. Flexible rings was implanted in 39 patients (29.3%, group F) and semi-rigid rings in 94 (70.7%, group R). Preoperative New York Heart Association class was III/IV in 104 patients (78.2%). Mean preoperative left ventricular ejection fraction was 28.8%±10.2%. Preoperative mitral regurgitation was moderate in 51 patients (38.3%) and severe in 82 (61.7%). In-hospital mortality occurred in 11 patients (8.3%). Overall survival at 1, 5 and 10 years were, respectively, 86.4%, 69.7% and 45.9%. At 10 years, overall survival (group F 53.1%, group R 40.0%, P=0.330) and freedom from moderate to severe MR (group F 53.1%, group R 53.8%, P=0.725) did not differ significantly. Freedom from hospitalization for heart failure was 59.3%. Left ventricular reverse remodelling, defined as a reduction of left ventricular end-systolic volume index >15%, occurred more commonly in Group R (51.1%) compared to Group F (23.1%), P=0.003. CONCLUSIONS: Restrictive mitral annuloplasty was associated with an operative mortality of 8.3%. Heart failure symptoms and significant MR recur in approximately 40% of patients after 10 years. Survival remained suboptimal and was not influenced by the type of annuloplasty ring.

Percutaneous Decommissioning of Left Ventricular Assist Device.

BACKGROUND: The left ventricular assist device (LVAD) has revolutionised our treatment of advanced stage heart failure, giving debilitated patients a new lease on life. A small proportion of these LVAD patients can be bridged-to-recovery. The identification of these patients and decision to wean, however, can be challenging. METHODS: The need to fully explant the device upon recovery has evolved to a minimalist approach aiming to avoid injury to the 'recovered' heart. A review of the evolution of explant strategies was performed to guide our decision to wean the LVAD in our early experience. RESULTS: Between 2009 and 2014, two patients in our series of 69 LVAD implants (2.9%) were successfully weaned off their LVADs. The second patient had a minimal access implantation of his HeartWare Ventricular Assist Device (HVAD, Medtronic Inc, Framingham, MA, USA). His clinical variables and minimalist weaning strategy are described. CONCLUSIONS: A case of LVAD decommissioning by thrombosis of the outflow graft, using percutaneous Amplatzer Vascular Plug II (St. Jude Medical, St. Paul, MN, USA) without surgery is reported.

Therapeutic Hypothermia May Improve Neurological Outcomes in Extracorporeal Life Support for Adult Cardiac Arrest.

BACKGROUND: Limited data exists on patients receiving therapeutic hypothermia during extracorporeal life support (ECLS). We investigated outcomes and prognostic factors in these patients. METHODS: A retrospective review was conducted for 225 consecutive adult patients treated with ECLS between July 2003 and January 2016. Extracorporeal life support was initiated for refractory cardiac arrest (>10 mins) in 79 patients (35.1%). Patient demographics, ECLS-related complications, in-hospital mortality and neurological outcomes were analysed. RESULTS: The mean age was 49.9±12.4 years. Sixty-two patients (78.5%) were male. The mean duration of CPR and ECLS were respectively, 32.0±23.3 mins and 5.4±4.0 days. Therapeutic hypothermia (34oC) was maintained for 24hours in 14 patients (17.7%). Thirty-five patients (44.3%) were weaned off ECLS. Twenty-one patients (26.6%) survived to hospital discharge with 16 (20.3%) recovering good neurological function. Compared to ECLS at normothermia, neurologically favourable survival was higher in the hypothermia group (42.9% vs 15.4%, p=0.020). Multivariable analysis identified a non-shockable rhythm [odds ratio (OR) 5.1, confidence interval (CI) 1.5-16.8], ischaemic hepatitis (OR 6.2, CI 1.1-33.6) and hypoxic ischaemic encephalopathy (OR 5.1, CI 1.5-17.1) as predictors of in-hospital mortality. Therapeutic hypothermia (OR 4.9, CI 1.2-20.4) and acute renal failure (OR 0.19, CI 0.05-0.70) were predictors of neurologically favourable survival. CONCLUSIONS: In this report of patients treated with ECLS, in-hospital survival and survival with good neurological performance were 26.6% and 20.3% respectively. A non-shockable rhythm, ischaemic hepatitis and hypoxic ischaemic encephalopathy were predictors of in-hospital mortality. Therapeutic hypothermia during ECLS was associated with improved neurological outcomes.

Novel Use of Thalidomide in Recurrent Gastrointestinal Tract Bleeding in Patients with Left Ventricular Assist Devices: A Case Series.

BACKGROUND: Bleeding is an important and common complication of left ventricular assist devices (LVADs). One of the common causes of gastrointestinal bleeding is arteriovenous malformations. However, the source of bleeding is often hard to identify. Thalidomide is efficacious in treatment of gastrointestinal (GI) bleeding in non-LVAD patients. We report our experience of the use of thalidomide in the treatment of GI bleeding in four patients with LVAD. METHOD AND RESULTS: Four patients who had recurrent GI bleeding from May 2009 to December 2014 were started on thalidomide. All of them responded to treatment and had no further gastrointestinal bleeding while on thalidomide. One patient developed constipation, requiring thalidomide to be stopped. Another patient developed symptomatic neuropathy, that resolved with reduction of dosage. CONCLUSION: Thalidomide appears safe and efficacious in LVAD patients with recurrent gastrointestinal bleeding.

Therapeutic hypothermia in adult patients receiving extracorporeal life support: early results of a randomized controlled study.

Cardiac arrest with cerebral ischaemia frequently leads to severe neurological impairment. Extracorporeal life support (ECLS) has emerged as a valuable adjunct in resuscitation of cardiac arrest. Despite ECLS, the incidence of permanent neurological injury remains high. We hypothesize that patients receiving ECLS for cardiac arrest treated with therapeutic hypothermia at 34 °C have lower neurological complication rates compared to standard ECLS therapy at normothermia. Early results of this randomized study suggest that therapeutic hypothermia is safe in adult patients receiving ECLS, with similar complication rates as ECLS without hypothermia. Further studies are warranted to measure the efficacy of this therapy.

Contained Rupture in HeartMate II Outflow Graft Bend Relief Disconnection.

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.

Changing glucose control target and risk of surgical site infection in a Southeast Asian population.

OBJECTIVE: Hyperglycemia is associated with surgical site infection and mortality in cardiac surgical patients. There is overriding evidence that glycemic control improves morbidity and mortality. However, the optimal glucose range in these patients remains controversial. Intensive glucose control can lead to mortality among critically ill adults because of episodic, moderate hypoglycemia. Therefore, we examined the effect of different glucose target control on the incidence of surgical site infection in our prospective cohort of diabetic and nondiabetic patients undergoing coronary artery bypass grafting. METHODS: Data from 1442 patients who underwent elective coronary artery bypass grafting at a tertiary heart center in Singapore from 2009 to 2011 were obtained. The first glucose level on arrival in the cardiothoracic intensive care unit was set at 4 to 8 mmol/L in 2009 and 2010 and 4 to 10 mmol/L in 2011. Glucose control was achieved with intravenous insulin infusion with a strict glucose monitoring protocol. Clinical covariates were analyzed, with surgical site infection as the primary outcome. RESULTS: The majority of patients presenting for coronary artery bypass grafting were male, Chinese, and diabetic. Diabetic patients had significantly higher glucose levels on arrival in the cardiothoracic intensive care unit. The change in target glucose control was independently associated with an increase in surgical site infection (odds ratio, 2.280; 95% confidence interval, 1.250-4.162; P = .007). Subgroup analysis revealed that unlike in nondiabetic patients, a less stringent target was independently associated with a significant increase in surgical site infection incidence from 2.2% to 6.9% for the diabetic patients (odds ratio, 3.131; 95% confidence interval, 1.431-6.851; P = .004). CONCLUSIONS: A target blood glucose of less than 8 mmol/L was associated with a lower incidence of surgical site infection in diabetic patients presenting for elective coronary artery bypass grafting in the local Southeast Asian population.

Surgical management of infective endocarditis: an analysis of early and late outcomes.

OBJECTIVES: To review our experience of surgical management of infective endocarditis (IE) over a 13-year period and analyse the outcomes and associated prognostic factors. METHODS: A retrospective review was conducted for 191 consecutive patients who underwent surgery for native and prosthetic valve endocarditis (PVE) between January 2000 and December 2012. Surgical outcomes were reviewed to include survival and postoperative complications. Follow-up was complete for 172 of 179 patients (96.1%) surviving to hospital discharge, with a mean follow-up of 6.6 ± 3.7 years. RESULTS: Mean age was 47.4 ± 14.9 years with 113 (63.9%) males. Native valve endocarditis was present in 177 patients (92.7%). Sixty-three patients (33.0%) presented with embolic complications. The brain was the most common site of embolism, involving 25 patients (13.1%). Streptococcus viridans was the most common infective organism, isolated in 68 patients (35.7%), followed by Staphylococcus aureus in 30 patients (15.7%). Eighty-seven patients (45.5%) had active endocarditis at the time of surgery. The mitral valve was infected in 136 patients (71.2%), the aortic valve in 66 (34.6%), the tricuspid valve in 29 (15.2%) and multiple valves in 38 (19.9%). Nineteen patients (9.9%) were intravenous drug users (IVDU). Twelve IVDUs (63.2%) suffered from tricuspid valve IE, compared with 7 of 162 patients (4.3%) in the non-IVDU population (P < 0.001). The most common indication for early surgery was intractable cardiac failure. Twelve patients (6.3%) died during the hospital stay for surgical treatment of IE. Logistic multivariate analysis identified preoperative creatinine clearance and stroke as independent predictors of in-hospital mortality. Overall 10-year survival and freedom from valve-related reoperation were 74.8 and 90.3%, respectively. Age, PVE, S. aureus endocarditis and postoperative left ventricular ejection fraction (LVEF) ≤45% were factors influencing long-term survival. CONCLUSIONS: Surgical management of endocarditis continues to be challenging and is associated with significant morbidity and mortality. This report of 191 patients who underwent valve surgery for IE shows that in-hospital mortality is influenced by preoperative renal function and stroke at the time of presentation. The optimal timing for surgery in patients with stroke remains controversial. Long-term survival was negatively influenced by increasing age, moderate to severely impaired LVEF, prosthetic valve IE and S. aureus infection.