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.

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.

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.

Quadriplegia post-coronary artery bypass graft surgery: an unusual case.

A 74-year-old Chinese man with triple-vessel coronary artery disease, developed quadriplegia following coronary artery bypass graft surgery, secondary to cervical disc anterior herniation and a C5-6 to T1 acute spinal hematoma. Preoperatively, no neurological signs or symptoms had been reported.

Evaluation of Cystatin C as a marker of renal injury following on-pump and off-pump coronary surgery.

OBJECTIVE: Cardiopulmonary bypass is regarded as an important contributor to renal injury, whereas off-pump surgery is considered less damaging. Cystatin C, a cystine protease inhibitor, is more sensitive and specific than creatinine in the assessment of renal function. We assessed the value of Cystatin C in quantifying clinical and subclinical renal injury following on-pump and off-pump cardiac surgery. METHODS: Sixty consecutive patients were recruited: 30 patients undergoing on-pump CABG and 30 patients undergoing off-pump CABG. Blood samples were collected pre-operatively and on days 1, 2 and 4 postoperatively to measure serum creatinine and serum Cystatin C. Urinary samples were collected concurrently to measure microalbumin and N-acetyl-beta-glucosaminidase, denoting changes in renal glomerular and tubular function respectively. RESULTS: The off-pump group were older (65+/-11 vs. 61+/-8 years; P=0.046), had a higher mean Parsonnet score (9.4+/-6.2 vs. 5.4+/-3.6, P<0.01) and received fewer grafts (2.4+/-0.9 vs. 3.1+/-0.7; P<0.01) compared to the on-pump group. The groups were otherwise matched with respect to preoperative renal function and left ventricular function. Patients undergoing on-pump CABG had greater increases in all four parameters of renal injury. Adjustment for preoperative differences increased the size and significance of the effect of off-pump vs. on-pump surgery (percent difference 13%; 95% CI 2-26 for creatinine, and 16%; 95% CI 4-29 for Cystatin C). Cystatin and creatinine were strongly correlated with each other. CONCLUSIONS: Avoidance of cardiopulmonary bypass may reduce renal injury particularly in higher risk patients. Cystatin C proved to be a simple and sensitive measure of overall renal function and can be used in the routine assessment of renoprotective strategies.

Anterior spinal artery syndrome after elective coronary artery bypass grafting.

A 65-year-old patient with ischemic heart disease and hypertensive nephropathy had paraplegia develop after elective coronary artery revascularization caused by anterior spinal infarction. Spinal complications are rare after coronary artery bypass grafting. The possible mechanisms of spinal cord injury are discussed, and the relevant literature is reviewed.