Gilbert Shardey

Usefulness of postoperative atrial fibrillation as an independent predictor for worse early and late outcomes after isolated coronary artery bypass grafting (multicenter Australian study of 19,497 patients).

Several studies have shown that postoperative atrial fibrillation (POAF) is associated with poorer short- and long-term outcomes after isolated coronary artery bypass grafting surgery. Nevertheless, there is considerable debate as to whether this reflects an independent association of POAF with poorer outcomes or confounding by other factors. We sought to investigate this issue. Data obtained from June 2001 through December 2009 by the Australasian Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database Program were retrospectively analyzed. Demographic and operative data were compared between patients who developed POAF and those who did not using chi-square and t tests. The independent impact of POAF on 14 short-term complications and long-term mortality was determined using binary logistic and Cox regression, respectively. Excluding patients with preoperative arrhythmia, isolated coronary artery bypass grafting surgery was performed in 19,497 patients. Of these, 5,547 (28.5%) developed POAF. Patients with POAF were generally older (mean age 69 vs 65 years, p <0.001) and presented more often with co-morbidities including congestive heart failure (p <0.001), hypertension (p <0.001), cerebrovascular disease (p <0.001), and renal failure (p = 0.046). Patients with POAF demonstrated a greater 30-day mortality on univariate analysis but not on multivariate analysis (p = 0.376). Patients with POAF were, however, at an independently increased risk of perioperative complications including permanent stroke (p <0.001), new renal failure (p <0.001), infective complications (p <0.001), gastrointestinal complications (p <0.001), and return to the theater (p <0.001). POAF was also independently associated with shorter long-term survival (p = 0.002). In conclusion, POAF is a risk factor for short-term morbidity and decreased long-term survival. Rigorous evaluation of various therapies that prevent or decrease the impact of POAF is imperative. Moreover, patients who develop POAF should undergo strict surveillance and be routinely screened for complications after discharge.

Contemporary Results Show Repeat Coronary Artery Bypass Grafting Remains a Risk Factor for Operative Mortality

BACKGROUND Reoperative coronary artery bypass grafting (redo CABG) shows improving outcomes, but with varying degrees of improvement. We assessed contemporary outcomes after redo CABG to determine if redo status is still a risk factor for early postoperative complications and midterm survival. METHODS Isolated CABG procedures (June 1, 2001 to May 31, 2008) within the Australasian Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database were included. Redo status as a predictor for early outcomes was assessed with logistic regression analysis. Midterm survival was determined from the National Death Index. Effect of redo status on midterm survival was assessed using a Cox proportional hazards model. RESULTS Inclusion criteria were met by 13,436 patients, and 458 (3.4%) underwent redo CABG. Operative mortality was 4.8% for redo CABG and 1.8% for first-time CABG (p < 0.001). After adjustment, redo status remained a predictor for operative mortality (odds ratio [OR], 2.1; 95% confidence interval [CI], 1.3 to 3.6), myocardial infarction (OR, 2.8; 95% CI, 1.6 to 6.0), and prolonged ventilation (OR, 1.5; 95% CI, 1.1 to 2.0). Unadjusted survival was lower for the redo CABG group vs the first-time CABG group at up to 6 years (p = 0.01, log-rank test. After adjusting for differences in patient variables, redo status was not a predictor of midterm survival (OR, 1.03; 95% CI, 0.78 to 1.35; p = 0.85). CONCLUSIONS Early postoperative outcomes of redo CABG are encouraging. Midterm survival is excellent; however, redo remains a significant risk factor for operative mortality in contemporary practice.

Sex differences in outcomes following isolated coronary artery bypass graft surgery in Australian patients: analysis of the Australasian Society of Cardiac and Thoracic Surgeons cardiac surgery database

OBJECTIVES Women undergoing isolated coronary artery bypass graft (CABG) surgery have been previously shown to be at an independently increased risk for post-operative morbidity and mortality. The current study evaluates the impact of sex as an independent risk factor for early and late morbidity and mortality following isolated CABG surgery. METHODS Data obtained between June 2001 and December 2009 by the Australasian Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database Program was retrospectively analysed. Demographic, operative data and post-operative complications were compared between male and female patients using chi-square and t-tests. Long-term survival analysis was performed using Kaplan-Meier survival curves and the log-rank test. Independent risk factors for short- and long-term mortality were identified using binary logistic and Cox regression, respectively. RESULTS CABG surgery was undertaken in 21 534 patients at 18 Australian institutions; 22.2% were female. Female patients were generally older (mean age, 68 vs. 65 years, P < 0.001) and presented more often with congestive heart failure (P < 0.001), hypertension (P < 0.001), diabetes mellitus (P < 0.001) and cerebrovascular disease (P < 0.001). Women demonstrated a greater 30-day mortality (2.2% vs. 1.5%, P < 0.001) on univariate analysis but not on multivariate analysis (P = 0.638). Similarly, women demonstrated a greater late mortality than men on univariate analysis (P = 0.006) but not on multivariate analysis (P = 0.093). Women had a decreased risk of early complications including new renal failure (P = 0.001) and deep sternal wound infection (P = 0.017) but were more likely to require red blood cell transfusion (P < 0.001). CONCLUSIONS Female patients undergoing isolated CABG surgery have a greater 30-day mortality which may be accounted for by a poorer pre-operative risk factor profile. Further investigation is required into the reasons for differential outcome after CABG based on sex.

Progress Towards a National Cardiac Procedure Database—Development of the Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) and Melbourne Interventional Group (MIG) Registries

Since the call for a National Cardiac Procedures Database in 2001, much work has been accomplished in both cardiac surgery and interventional cardiology in an attempt to establish a unified, systematic approach to data collection, defining a common minimum dataset pertinent to the Australian context, and instituting quality control measures to ensure integrity and privacy of data. In this paper we outline the aims of the Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) and the Melbourne Interventional Group (MIG) registries, and propose a comprehensive set of standardised data elements and their definitions to facilitate transparency in data collection, consistency between these and other data sets, and encourage ongoing peer-review. The aims are to improve outcomes for patients by determining key performance indicators and standards of performance for hospital units, to allow estimation of procedural risks and likelihood of outcomes for patients, and to report outcomes to relevant stake-holders and the public.

A preoperative risk prediction model for 30-day mortality following cardiac surgery in an Australian cohort

BACKGROUND Population-specific risk models are required to build consumer and provider confidence in clinical service delivery, particularly when the risks may be life-threatening. Cardiac surgery carries such risks. Currently, there is no model developed on the Australian cardiac surgery population and this article presents a novel risk prediction model for the Australian cohort with the aim to provide a guide for the surgeons and patients in assessing preoperative risk factors for cardiac surgery. AIMS This study aims to identify preoperative risk factors associated with 30-day mortality following cardiac surgery for an Australian population and to develop a preoperative model for risk prediction. METHODS All patients (23016) undergoing cardiac surgery between July 2001 and June 2008 recorded in the Australian Society of Cardiac and Thoracic Surgeons (ASCTS) database were included in this analysis. The data were divided randomly into model creation (13810, 60%) and model validation (9206, 40%) sets. The model was developed on the creation set and then validated on the validation set. The bootstrap sampling and automated variable selection methods were used to develop several candidate models. The final model was selected from this group of candidate models by using prediction mean square error (MSE) and Bayesian Information Criteria (BIC). Using a multifold validation, the average receiver operating characteristic (ROC), p-value for Hosmer-Lemeshow chi-squared test and MSE were obtained. Risk thresholds for low-, moderate- and high-risk patients were defined. The expected and observed mortality for various risk groups were compared. The multicollinearity and first-order interaction effect between clinically meaningful risk factors were investigated. RESULTS A total of 23016 patients underwent cardiac surgery and the 30-day mortality rate was 3.2% (728 patients). Independent predictors of mortality in the model were: age, sex, the New York Heart Association (NYHA) class, urgency of procedure, ejection fraction estimate, lipid-lowering treatment, preoperative dialysis, previous cardiac surgery, procedure type, inotropic medication, peripheral vascular disease and body mass index (BMI). The model had an average ROC 0.8223 (95% confidence interval (CI): 0.8118-0.8227), p-value 0.8883 (95% CI: 0.8765-0.90) and MSE 0.0251 (95% CI: 0.02515-0.02516). The validation set had observed mortality 3.0% (95% CI: 2.7-3.3%) and predicted mortality 2.9% (95% CI: 2.6-3.2%). The low-risk group (additive score 0-3) had 0.6% observed mortality (95% CI: 0.3-0.9%) and 0.5% predicted mortality (95% CI: 0.2-0.8%). The moderate-risk group (additive score 4-9) had 1.7% observed mortality (95% CI: 1.2-2.2%) and 1.4% predicted mortality (95% CI: 1.0-1.8%). The observed mortality for the high-risk group (additive score 9 plus) was 6.7% (95% CI: 5.8-7.6%) and the expected mortality was 6.7% (95% CI: 5.8-7.6%). CONCLUSION A preoperative risk prediction model for 30-day mortality was developed for the Australian cardiac surgery population.

Critical analysis of early and late outcomes after isolated coronary artery bypass surgery in elderly patients.

BACKGROUND The proportion of elderly (≥80 years) patients undergoing coronary artery bypass surgery (CABG) is increasing. METHODS A retrospective analysis of data, collected by the Australasian Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database Program between June 2001 and December 2009 was performed. Isolated CABG was performed in 21,534 patients; of these, 1,664 (7.7%) were at least 80 years old (group 1). Patient characteristics, morbidity, and short-term mortality of these patients were compared with those aged less than 80 years (group 2). The long-term outcome of group 1 patients after CABG surgery was compared with an age and sex-matched Australian population. RESULTS Patients over 80 years old were more likely to be female (36.6% vs 17.3%, p < 0.001) and presented significantly more often with heart failure, hypertension, and triple-vessel disease (all p < 0.05). The 30-day mortality was higher in group 1 patients (4.2% vs 1.5%, p < 0.001). Group 1 patients also had an increased risk of complications, including prolonged (>24 hours) ventilation (14.2% vs 8.2%, p < 0.001), renal failure (7.3% vs 3.4%, p < 0.001), and mean intensive care unit stay (60.7 vs 42.5 hours, p < 0.001). The 5-year survival of elderly patients (73%) was comparable with the age-matched Australian population. Independent risk factors for 30-day mortality in group 1 patients included preoperative renal failure (p = 0.010), congestive heart failure (p = 0.014), and a nonelective procedure (p = 0.016). CONCLUSIONS Elderly patients who undergo isolated CABG have significantly lower perioperative risks than have been previously reported. The long-term survival of these patients is comparable with an age-adjusted population.

Does Prior Percutaneous Coronary Intervention Adversely Affect Early and Mid-Term Survival After Coronary Artery Surgery?

OBJECTIVES To determine the association between previous percutaneous coronary intervention (PCI) and results after coronary artery bypass graft surgery (CABG). BACKGROUND Increasing numbers of patients undergoing CABG have previously undergone PCI. METHODS We analyzed consecutive first-time isolated CABG procedures within the Australasian Society of Cardiac and Thoracic Surgeons Database from June 2001 to May 2008. Logistic regression and propensity score analyses were used to assess the risk-adjusted impact of prior PCI on in-hospital mortality and major adverse cardiac events. Cox regression model was used to assess the effect of prior PCI on mid-term survival. RESULTS Of 13,184 patients who underwent CABG, 11,727 had no prior PCI and 1,457 had prior PCI. Mean follow-up was 3.3 +/- 2.1 years. Patients without prior PCI had a higher EuroSCORE value (4.4 +/- 3.3 vs. 3.6 +/- 3.0, p < 0.001), were older, and more likely to have left main stem stenosis and recent myocardial infarction. There was no difference in unadjusted in-hospital mortality (1.65% vs. 1.55%, p = 0.78) or major adverse cardiac events (3.0% vs. 3.0%, p = 0.99) between patients with or without prior PCI. After adjustment, prior PCI was not a predictor of in-hospital (odds ratio: 1.22, 95% confidence interval [CI]: 0.76 to 2.0, p = 0.41) or mid-term mortality at 6-year follow-up (hazard ratio: 0.94, 95% CI: 0.75 to 1.18, p = 0.62). CONCLUSIONS In this large registry study, prior PCI was not associated with increased short- or mid-term mortality after CABG. Good outcomes can be obtained in the group of patients undergoing CABG who have had previous PCI.

Quality Control Activities Associated with Registries in Interventional Cardiology and Surgery

OBJECTIVE To describe and outline audit and quality control activities of the multicentre interventional and cardiac surgery registry in Victoria as a potential model for a national registry. DESIGN, SETTING, AND PATIENTS The Melbourne Interventional Group (MIG) database is a prospective multicentre registry recording consecutive percutaneous coronary interventional (PCI) procedures across eight Victorian hospitals. Similarly, the Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) database captures cardiac surgical activity across six Victorian hospitals. Auditing of each registry involved systematic selection of baseline, clinical and procedural variables from 5% of procedures to examine for data integrity and mismatches. MAIN OUTCOME MEASURES Performance trend and data accuracy of each registry was assessed by the number of mismatches detected during the auditing process for different demographic, clinical and procedural variables and across different (de-identified) sites. RESULTS Over two auditing phases from 2004-2006 and 2007, 10 (4.3%) of variables from 3% of all PCI procedures and 15 (6.4%) variables from 5% of PCI procedures were analysed. There was 96.5% agreement during the first auditing phase of the MIG registry with an average of 0.35 mismatches per audit (CI 0.28-0.42), whereas during the second audit phase, agreement was up to 97% with 0.32 mismatches per 10 fields per audit (CI 0.25-0.40). The ASCTS database audit selected 39 (14.8%) variables from 5% of annual surgical cases across six cardiac surgical centres with an overall 96.7% agreement. CONCLUSION The current auditing process of these two databases is rigorous, robust and reflects a high degree of accuracy of data collected by participating hospitals.

Clinical characteristics and early mortality of patients undergoing coronary artery bypass grafting compared to percutaneous coronary intervention: Insights from the Australasian Society of Cardiac and Thoracic Surgeons (ASCTS) and the Melbourne Interventional Group (MIG) Registries

OBJECTIVES Controversy continues over the optimal revascularisation strategy for patients with multi-vessel coronary artery disease. Clinical characteristics, risk profile, and mortality of patients undergoing coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI) are thought to differ but there are limited contemporary comparative data. METHODS We compared clinical characteristics, in-hospital and 30-day mortality of 3841 consecutive patients undergoing isolated CABG and 4417 undergoing PCI. Independent predictors of 30-day mortality were determined by multiple logistic regression analysis. RESULTS CABG patients were older (p<0.01). The CABG group had a higher incidence of diabetes, heart failure, left ventricular ejection fraction <45%, multi-vessel coronary artery, peripheral vascular and cerebro-vascular disease (all p<0.01). Patients undergoing PCI had a higher incidence of recent myocardial infarction (MI) as the indication for revascularisation (p<0.01). In-hospital and 30-day mortality was 1.8% and 1.7% in the CABG group, and 1.4% and 1.8% in the PCI group, respectively. Independent predictors of 30-day mortality after CABG were age (odds ratio 1.1 per year, 95% confidence interval 1.0-1.1), cardiogenic shock (4.10, 1.7-10.5) and previous CABG (6.6, 2.4-17.7). Predictors after PCI were diabetes (2.7, 1.4-5.1), female gender (3.0, 1.6-5.5), renal failure (3.2, 1.2-8.0), MI<24h (4.0, 2.2-7.6), left main intervention (5.4, 1.0-27.7), heart failure (6.0, 2.6-14.0) and cardiogenic shock (11.7, 5.4-25.2). CONCLUSIONS In contemporary clinical practice, CABG is preferred in patients with multi-vessel coronary and associated non-coronary vascular disease, while PCI is the dominant strategy for acute MI. Despite this, in-hospital and 30-day mortality rates were similar. Predictors of early mortality after CABG differ to those of PCI.

Early and late outcomes after isolated aortic valve replacement in octogenarians: an Australasian Society of Cardiac and Thoracic Surgeons Cardiac Surgery Database Study

OBJECTIVE The advent of percutaneous aortic valve implantation has increased interest in the outcomes of conventional aortic valve replacement in elderly patients. The current study critically evaluates the short-term and long-term outcomes of elderly (≥80 years) Australian patients undergoing isolated aortic valve replacement. METHODS Data obtained prospectively between June 2001 and December 2009 by the Australasian Society of Cardiac and Thoracic Surgeons National Cardiac Surgery Database Program were retrospectively analysed. Isolated aortic valve replacement was performed in 2791 patients; of these, 531 (19%) were at least 80 years old (group 1). The patient characteristics, morbidity and short-term mortality of these patients were compared with those of patients who were <80 years old (group 2). The long-term outcomes in elderly patients were compared with the age-adjusted Australian population. RESULTS Group 1 patients were more likely to be female (58.6% vs 38.0%, p<0.001) and presented more often with co-morbidities including hypertension, cerebrovascular disease and peripheral vascular disease (all p<0.05). The 30-day mortality rate was not independently higher in group 1 patients (4.0% vs 2.0%, p=0.144). Group 1 patients had an independently increased risk of complications including new renal failure (11.7% vs 4.2%, p<0.001), prolonged (≥24 h) ventilation (12.4% vs 7.2%, p=0.003), gastrointestinal complications (3.0% vs 1.3%, p=0.012) and had a longer mean length of intensive care unit stay (64 h vs 47 h, p<0.001). The 5-year survival post-aortic valve replacement was 72%, which is comparable to that of the age-matched Australian population. CONCLUSION Conventional aortic valve replacement in elderly patients achieves excellent outcomes with long-term survival comparable to that of an age-adjusted Australian population. In an era of percutaneous aortic valve implantation, it should still be regarded as the gold standard in the management of aortic stenosis.