Shortening cardioplegic arrest time in patients undergoing combined coronary and valve surgery: results from a multicentre randomized controlled trial: the SCAT trial.

OBJECTIVES: Combined coronary artery bypass grafting and valve surgery requires a prolonged period of cardioplegic arrest (CA) predisposing to myocardial injury and postoperative cardiac-specific complications. The aim of this trial was to reduce the CA time in patients undergoing combined coronary artery bypass grafting and valve surgery and assess if this was associated with less myocardial injury and related complications. METHODS: Participants were randomized to (i) coronary artery bypass grafting performed on the beating heart with cardiopulmonary bypass support followed by CA for the valve procedure (hybrid) or (ii) both procedures under CA (conventional). To assess complications related to myocardial injury, we used the composite of death, myocardial infarction, arrhythmia, need for pacing or inotropes for >12 h. To assess myocardial injury, we used serial plasma troponin T and markers of metabolic stress in myocardial biopsies. RESULTS: Hundred and sixty patients (80 hybrid and 80 conventional) were randomized. Mean age was 66.5 years and 74% were male. Valve procedures included aortic (61.8%) and mitral (33.1%) alone or in combination (5.1%). CA time was 16% lower in the hybrid group [median 98 vs 89 min, geometric mean ratio (GMR) 0.84, 95% confidence interval (CI) 0.77-0.93, P = 0.0004]. Complications related to myocardial injury occurred in 131/160 patients (64/80 conventional, 67/80 hybrid), odds ratio 1.24, 95% CI 0.54-2.86, P = 0.61. Release of troponin T was similar between groups (GMR 1.04, 95% CI 0.87-1.24, P = 0.68). Adenosine monophosphate was 28% lower in the hybrid group (GMR 0.72, 95% CI 0.51-1.02, P = 0.056). CONCLUSIONS: The hybrid procedure reduced the CA time but myocardial injury outcomes were not superior to conventional approach. TRIAL REGISTRATION: ISRCTN65770930.

Nitric oxide donating aspirins: novel drugs for the treatment of saphenous vein graft failure.

BACKGROUND: A new class of nitric oxide donating aspirin (NO-ASA) drugs may increase the therapeutic impact of aspirin in saphenous vein coronary artery bypass grafting (CABG) not only through the inhibition of thrombosis but also through a reduction of vasospasm and inhibition of vascular smooth muscle cell (VSMC) proliferation (effects that are inhibited by NO but not ASA). In order to test this proposal the effect of three NO-ASA drugs (NCX4040, NCX4050, and NCX4060) on in vitro relaxation and cyclic guanosine monophosphate (cGMP) formation in the human isolated saphenous vein and the proliferation of human VSMCs was investigated. METHODS: Saphenous vein segments were obtained from 30 patients undergoing CABG (median age, 59 years; range, 49 to 68). The effect of the NO-ASA adducts, ASA alone, and sodium nitroprusside (NO donor) were investigated on (1) relaxation of phenylephrine-stimulated contraction using an organ bath, (2) cyclic guanosine monophosphate (cGMP) formation using an enzyme-linked immunosorbent assay, and (3) the proliferation of VSMCs derived from saphenous vein using bromo-deoxyuridine (BRDU) incorporation. RESULTS: All three NO-ASA adducts (at concentrations that inhibited responses by 50% [IC50s] between 1 micromol/L and 100 micromol/L) and nitroprusside (at IC50s between 0.5 and 10 micromol/L) elicited relaxation of isolated human saphenous vein, promoted cGMP formation, and inhibited VSMC proliferation whereas ASA alone (up to 100 micromol/L) had no effect on any variable. CONCLUSIONS: These data indicate that the NO-ASA adducts by virtue of their capacity to release NO and stimulate guanylyl cyclase may be useful not only in the prevention of thrombosis following CABG but also the reduction of saphenous vein graft spasm and neointima formation.

Early and midterm clinical outcome in patients with severe left ventricular dysfunction undergoing coronary artery surgery.

BACKGROUND: Patients presenting with severe left ventricular (LV) dysfunction undergoing coronary artery surgery are at increased risk of perioperative morbidity and mortality. The present study investigated early and midterm outcomes in a consecutive series of patients with severe LV dysfunction undergoing coronary surgery at our institution. METHODS: Data on 5,195 consecutive patients undergoing coronary artery bypass grafting (CABG) alone (in-hospital mortality 1.35%) from April 1996 to August 2002 were prospectively recorded in the Patient Analysis and Tracking System. Two hundred and fifty patients (median age 65 years [interquartile range, 57 to 70]) with preoperative left ventricular ejection fraction less than 30% (74 off pump; 29.6%) were identified and early and midterm clinical outcomes analyzed. Propensity scores were used to take account of the imbalance in the distribution of prognostic factors between the on-pump and off-pump groups. RESULTS: Patients undergoing on-pump surgery were less likely to have current congestive heart failure, insulin-dependent diabetes, a history of hypertension, have had gastrointestinal tract surgery or an ulcer, or unstable angina. They had on average lower Parsonnet scores and New York Heart Association and Canadian Cardiovascular Score ratings. However they were more likely to have more extensive coronary artery heart disease and to require more grafts than those undergoing off-pump surgery. After adjustment for consultant team and propensity scores no differences between groups with regard to in-hospital mortality and morbidity were found. The only in-hospital outcome to show a significant difference after adjustment was the need for intraoperative inotropic support, which was higher in the on-pump group (odds ratio 5.1; 95% confidence interval 2.55 to 10.2; p < 0.001)). The median follow-up times for the on- and off-pump groups were 3.4 years and 1.4 years respectively. Three-year survival was higher with on-pump surgery (87% on-pump versus 73% off-pump) but this difference did not reach statistical significance after adjustment for prognostic variables (hazard ratio 0.54, 95% confidence interval 0.22 to 1.26, p = 0.16). CONCLUSIONS: In-hospital mortality and morbidity in patients presenting with severe LV dysfunction is low with comparable results with both on- and off-pump coronary artery surgery. Midterm clinical outcome is encouraging and seems to justify surgical revascularization for this high-risk group of patients.

The evolution of training in off-pump coronary surgery in a single institution.

BACKGROUND: This study analyses the development of off-pump coronary artery bypass (OPCAB) surgery training at a single institution, and compares the early and midterm clinical outcomes of OPCAB and conventional coronary artery bypass grafting (CABG) procedures performed by trainees with or without direct consultant cardiothoracic surgeon supervision. METHODS: Analysis was undertaken on data prospectively recorded on a computer database (Patient Analysis and Tracking System). Of the 2,422 CABG operations performed between January 1999 and December 2001, 969 (40%) were carried out by trainees either off pump (422) or on pump (547). RESULTS: Although the total number of CABG operations performed by trainees remained constant, there was a significant increase in the number of OPCAB operations during the study period compared with conventional CABG, as well as an increase in the average number of grafts per patient in the OPCAB group (both p < 0.05). Furthermore, a significant trend towards using two or more arterial conduits in the OPCAB group was observed in the study period. The number of OPCAB operations performed by trainees as independent operators without direct consultant supervision also increased significantly (p < 0.05). Early and midterm clinical outcomes were similar between patients operated by trainees on pump or off pump as independent operators versus under direct consultant supervision. CONCLUSIONS: The significant increase in OPCAB operations performed by trainees as independent operators or under direct consultant supervision, as well as the increase in the number of grafts per patient and arterial conduits used for myocardial revascularization, demonstrate a progression of training in beating heart surgery for cardiothoracic trainees. Improvements in the techniques have made it safe to teach trainees off-pump multivessel coronary artery revascularization.

Occult renal dysfunction: a mortality and morbidity risk factor in coronary artery bypass grafting surgery.

OBJECTIVE: Elevated preoperative serum creatinine is considered an independent risk factor for postoperative mortality and morbidity in patients undergoing coronary artery bypass grafting. However, the impact of occult renal dysfunction, defined as an impairment of glomerular filtration rate with normal serum creatinine, is still unknown. The aim of this study was to analyze the effects of occult renal dysfunction on early outcomes after coronary artery bypass grafting. METHODS: This was a retrospective, observational, cohort study of prospectively collected data on 9159 consecutive patients with normal serum creatinine levels undergoing coronary artery bypass grafting between April 1996 and February 2009. Patients were divided into two groups based on preoperative creatinine clearance estimated with the Cockcroft-Gault equation: 5484 patients with a creatinine clearance ≥ 60 mL/min and 3675 patients with a creatinine clearance < 60 mL/min (occult renal dysfunction group). RESULTS: Overall in-hospital mortality was 1%. Occult renal dysfunction was associated with a doubling in the risk of operative mortality (1.4% vs 0.7%; P = .001), postoperative renal dysfunction (5.1% vs 2.5%; P < .0001), and need for dialysis (0.8% vs 0.4%; P = .014). Moreover, occult renal dysfunction increased the risk of stroke (1% vs 0.3%; P < .0001), arrhythmia (28.5% vs 21.2%; P < .0001), and hospital stay > 7 days (36.45 vs 24.5%; P < .0001). In a multivariable analysis adjusting for preoperative risk factors, occult renal dysfunction was confirmed to be an independent predictor of mortality (odds ratio, 1.72), postoperative renal dysfunction (odds ratio, 1.9), dialysis (odds ratio, 1.82), stroke (odds ratio, 2.6) arrhythmia (odds ratio, 1.42), and hospital stay > 7 days (odds ratio, 1.65). CONCLUSIONS: Occult renal dysfunction is an independent risk factor for early mortality and morbidity in patients undergoing coronary artery bypass grafting.

Mild renal dysfunction in patients undergoing cardiac surgery as a new risk factor for EuroSCORE.

BACKGROUND: It has recently been suggested that mild renal dysfunction is associated with increased mortality in cardiac surgery; however, this risk factor is not accounted for in the European System for Cardiac Operative Risk Evaluation (EuroSCORE). The aim of the present study was to assess the effect of mild renal dysfunction as a predictor of operative mortality and develop and validate a modified logistic EuroSCORE model. METHODS: This was a retrospective, observational, cohort study of prospectively collected data on 16 086 consecutive patients undergoing cardiac surgery at the Bristol Heart Institute between April 1996 and February 2009. To develop a modified logistic EuroSCORE, data were dived into developmental and validation datasets (11 596 and 4490 patients respectively). The relationship between risk factors and mortality was assessed using univariate and logistic regression analysis. Calibration and discrimination were assessed by Hosmer Lemeshow χ(2) test and receiving operative characteristic (ROC) curve. RESULTS: Overall hospital mortality was 2.6%. At multivariate analysis, 13 out of 18 variables of the EuroSCORE influenced operative mortality; moreover, preoperative mild renal dysfunction, defined as serum creatinine 130-199 µmol/l, was identified as a new risk factor for mortality (OR 1.819, 95% CI 1.353 to 2.447, p<0.0001). EuroSCORE was able to predict mortality; however, modified logistic EuroSCORE had a better discriminatory power (area under ROC: 0.844 vs 0.784, p=0.002). CONCLUSIONS: Preoperative mild renal dysfunction is an independent risk factor for mortality in patients undergoing cardiac surgery. These findings now need to be validated with data from other centres.

A clinical score to predict the need for intraaortic balloon pump in patients undergoing coronary artery bypass grafting.

BACKGROUND: There is no accepted consensus on the definition of high-risk patients who may benefit from the use of intraaortic balloon pump (IABP) in coronary artery bypass grafting (CABG). The aim of this study was to develop a risk model to identify high-risk patients and predict the need for IABP insertion during CABG. METHODS: From April 1996 to December 2006, 8,872 consecutive patients underwent isolated CABG; of these 182 patients (2.1%) received intraoperative or postoperative IABP. The scoring risk model was developed in 4,575 patients (derivation dataset) and validated on the remaining patients (validation dataset). Predictive accuracy was evaluated by the area under the receiver operating characteristic curve. RESULTS: Mortality was 1% in the entire cohort and 18.7% (22 patients) in the group which received IABP. Multivariable analysis showed that age greater than 70 years, moderate and poor left ventricular dysfunction, previous cardiac surgery, emergency operation, left main disease, Canadian Cardiovascular Society 3-4 class, and recent myocardial infarction were independent risk factors for the need of IABP insertion. Three risk groups were identified. The observed probability of receiving IABP and mortality in the validation dataset was 36.4% and 10% in the high-risk group (score >14), 10.9% and 2.8% in the medium-risk group (score 7 to 13), and 1.7% and 0.7% in the low-risk group (score 0 to 6). CONCLUSIONS: This simple clinical risk model based on preoperative clinical data can be used to identify high-risk patients who may benefit from elective insertion of IABP during CABG.

Effects of angiotensin-converting enzyme inhibitor therapy on clinical outcome in patients undergoing coronary artery bypass grafting.

OBJECTIVES: This study evaluates the effect of pre-operative angiotensin-converting enzyme inhibitor (ACEI) therapy on early clinical outcomes after coronary artery bypass grafting (CABG). BACKGROUND: Therapy with ACEIs has been shown to reduce the rate of mortality and prevent cardiovascular events in patients with coronary artery disease. However, their pre-operative use in patients undergoing CABG is still controversial. METHODS: A retrospective, observational, cohort study was undertaken of prospectively collected data on 10,023 consecutive patients undergoing isolated CABG between April 1996 and May 2008. Of these, 3,052 patients receiving pre-operative ACEI were matched to a control group by propensity score analysis. RESULTS: Overall rate of mortality was 1%. Pre-operative ACEI therapy was associated with a doubling in the risk of death (1.3% vs. 0.7%; odds ratio [OR]: 2.00, 95% confidence interval [CI]: 1.17 to 3.42; p = 0.013). There was also a significant difference between the ACEI and control group in the risk of post-operative renal dysfunction (PRD) (7.1% vs. 5.4%; OR: 1.36, 95% CI: 1.1 to 1.67; p = 0.006), atrial fibrillation (AF) (25% vs. 20%; OR: 1.34, 95% CI: 1.18 to 1.51; p < 0.0001), and increased use of inotropic support (45.9% vs. 41.1%; OR: 1.22, 95% CI: 1.1 to 1.36; p < 0.0001). In a multivariate analysis, pre-operative ACEI treatment was an independent predictor of mortality (p = 0.04), PRD (p = 0.0002), use of inotropic drugs (p < 0.0001), and AF (p < 0.0001). CONCLUSIONS: Pre-operative therapy with ACEI is associated with an increased risk of mortality, use of inotropic support, PRD, and new onset of post-operative AF.

Coronary surgery in patients with preexisting chronic atrial fibrillation: early and midterm clinical outcome.

BACKGROUND: The purpose of this study was to investigate the effect of preexisting atrial fibrillation on early and midterm clinical outcome in patients undergoing coronary surgery. METHODS: All elective patients undergoing coronary artery bypass grafting surgery between April 1996 and September 2002 were investigated. Patients were grouped according to their preoperative cardiac rhythm: sinus rhythm (SR) or preexisting atrial fibrillation (AF). In-hospital clinical outcomes and 5-year patient survival and cardiac-related event-free survival were compared using regression methods to adjust for differences between the groups. In all, 5,092 patients were identified, 175 (3.4%) with a history of preexisting AF. These patients were older (median, 64 versus 68 years) and had higher Parsonnet scores (median, 4 versus 8) than the SR group. Previous myocardial infarction, cerebrovascular accident, hypertension, diabetes mellitus, renal impairment, peripheral vascular disease, ejection fraction less than 50%, previous surgery, congestive heart failure, and use of angiotensin-converting enzyme inhibitors were also more common in the AF group. RESULTS: There were 60 in-hospital deaths (1.2%), with no difference between the two groups (odds ratio 1.02, 95% CI: 0.35 to 2.94). Atrial fibrillation patients were more likely to need intraoperative inotropes (p = 0.044), postoperative intra-aortic balloon pump (p = 0.038), and were less likely to be discharged within 6 days (p = 0.017). The risk of death in the 5 years after surgery was higher in the AF group (relative risk 1.49, 95% CI: 1.06 to 2.08, p = 0.020). In the AF group, 109 (62.2%) patients were cardioverted spontaneously by surgery, but only 69 (39.4%) remained in SR until discharge. Longer-term rhythm follow-up data were available for 48 of these 69 patients, and only 36 remained in SR at a median follow-up of 1,483 days (interquartile range, 1,120 to 2,209). Spontaneous conversion to SR after surgery did not confer a midterm survival benefit (p = 0.91). CONCLUSIONS: Preexisting AF in patients undergoing coronary artery bypass graft surgery is not associated with increased in-hospital mortality and major morbidity; however, it is a risk factor for reduced 5-year survival. Spontaneous cardioversion to SR during surgery is transient in the majority of patients and is not associated with midterm survival benefit.