Clinical implications of QRS duration and QT peak prolongation in patients with suspected coronary disease referred for elective cardiac catheterization.

BACKGROUND: The electrocardiogram (ECG) remains a simple, universally available, and prognostically powerful investigation in heart failure, and acute coronary syndromes. We sought to assess the prognostic utility of clinical, angiographic, and simple ECG parameters in a large cohort of patients undergoing elective cardiac catheterization (CC) for known or suspected coronary artery disease. METHODS: Consecutive consenting patients undergoing CC for coronary disease were enrolled at a single tertiary center. Patient data, drug therapy, catheter reports, and ECG recordings were prospectively recorded in a validated electronic archive. The primary outcome measure was death or nonfatal myocardial infarction (MI) over 1 year or until percutaneous or cardiac surgical intervention. Independent prognostic markers were identified using the Cox proportional hazard model. RESULTS: A total of 682 individuals were recruited of whom 17(2.5%) died or suffered a nonfatal MI in 1 year. In multivariate analysis QRS duration (ms) (HR 1.03 95% CI 1.01-1.05, P = 0.003), extent of coronary disease (HR 2.01 95% CI 1.24-3.58, P = 0.006), and prolonged corrected QT peak interval in lead I (HR 1.02 95% CI 1.00-1.03, P = 0.044) were independently associated with death or nonfatal MI. Receiver-operator characteristic (ROC) analysis for the multivariate model against the primary end point yielded an area under the curve of 0.759 (95% CI 0.660-0.858), P < 0.001. CONCLUSIONS: QRS duration and QT peak are independently associated with increased risk of death or nonfatal MI in stable patients attending for coronary angiography.

Spectral analysis, death and coronary anatomy following cardiac catheterisation.

OBJECTIVE: To establish the associations and prognostic utility of angiographic, clinical and HRV parameters in a large cohort of patients undergoing diagnostic cardiac catheterisation (CC). METHODS: Patients undergoing CC as elective day cases were enrolled at a single tertiary center from September 2001 to January 2003. Patient data, serum biochemistry, current drug therapy, catheter reports and five minute high resolution electrocardiograph (ECG) recordings were prospectively recorded and validated in an electronic archive. ECG recordings were used to generate time domain (SDNN (standard deviation of NN intervals)) and spectral HRV parameters (low frequency (LF) and high frequency (HF) power). Significant associations between dichotomized HRV variables and covariates were investigated using binary logistic regression. The independent prognostic ability of clinical markers was evaluated using the Cox proportional hazard model. RESULTS: 841 consecutive consenting patients of mean age 61+/-10 years were recruited into the study with a mean follow-up period of 690+/-436 days. In multivariate analysis decreasing LF spectral power was independently associated with proximal right coronary stenosis OR (odds ratio)=1.65 (95% CI=1.16-2.36), P=0.006 and to all cause mortality OR=5.01 (95% CI=1.47-17.01), P=0.010. Increasing LF power was also independently associated with normal coronary angiograms in patients investigated suspected coronary disease without a confirmed prior history of a coronary ischaemic event OR=2.16 (95% CI=1.26-3.73), P=0.002. CONCLUSIONS: Reduced LF power independently predicts all cause mortality in a large cohort of patients receiving medical therapy after elective CC. LF power was also independently associated with >75% proximal RCA stenosis.

Impact of avoiding cardiopulmonary bypass for coronary surgery on perioperative cardiac enzyme release and survival.

OBJECTIVE: This study examines the association between avoiding the use of cardiopulmonary bypass (CPB) for coronary surgery and postoperative cardiac enzyme (CE) release, and its subsequent impact on survival. METHODS: Between January 1999 and September 2002, 3734 consecutive patients underwent either off-pump or on-pump coronary surgery. Patient characteristics and postoperative cardiac enzyme release were collected prospectively. Logistic regression was used to assess the effect of off-pump coronary surgery on cardiac enzyme release. All analyses were adjusted for preoperative characteristics and number of grafts. All patients were followed up at 1 year to assess survival. RESULTS: Nine hundred and sixty (25.7%) patients had off-pump coronary surgery. Seven hundred and twenty-six (19.4%) patients had cardiac enzyme release three to six times the upper limit of the reference range, while 266 (7.1%) patients had cardiac enzyme release more than six times the upper limit of the reference range. After adjusting for patient characteristics, off-pump surgery was associated with less release (cardiac enzyme release three to six times, adjusted odds ratio 0.43, p<0.001; cardiac enzyme release more than six times, adjusted odds ratio 0.59, p=0.005). Risk adjusted survival at 1 year was 97.5% for the on-pump group and 97.0% for the off-pump group (p=0.33). CONCLUSIONS: Avoiding cardiopulmonary bypass significantly reduces early cardiac enzyme release following coronary artery bypass grafting (CABG). However, it does not result in improved survival compared to coronary surgery using cardiopulmonary bypass. This absence of survival benefit may be due to higher mortality rates experienced by the fewer patients with high (>6 times the upper limit of range) cardiac enzyme release following coronary artery bypass surgery without cardiopulmonary bypass.

Preoperative white blood cell count is independently associated with higher perioperative cardiac enzyme release and increased 1-year mortality after coronary artery bypass grafting.

BACKGROUND: Elevated preprocedural systemic markers of inflammation, including white blood cell count, have been associated with adverse clinical outcomes after percutaneous coronary intervention. The relationship between preoperative white blood cell count and clinical outcomes after coronary artery bypass grafting is less clear despite increasing evidence that neutrophils participate in reperfusion injury. We sought to determine the relationship between preoperative white blood cell count and in hospital major morbidity and 1-year survival after coronary artery bypass grafting. METHODS: We prospectively studied 3,024 consecutive isolated coronary artery bypass graft procedures. Preoperative white blood cell count was determined by automated counter, perioperative cardiac enzyme release by the creatine kinase-myocardial band isoenzyme, and all-cause mortality over the first postoperative year taken from a national death registry. Multivariate logistic regression and Cox proportional hazards analyses were performed. RESULTS: Preoperative white blood cell count offered as a continuous variable and as five predetermined groups was independently associated with cardiac enzyme release three or more times the upper limit of the reference range (adjusted odds ratio = 1.5 per 10 x 10(9)/L increase, 95% confidence interval: 1.2 to 2.0, p = 0.002) and higher 1-year mortality (adjusted hazard ratio = 1.6 per 10 x 10(9)/L increase, 95% confidence interval: 1.2 to 2.1, p < 0.001). CONCLUSIONS: Higher preoperative white blood cell count is independently associated with higher perioperative myonecrosis and 1-year mortality after coronary artery bypass grafting.

Effect of peri-operative red blood cell transfusion on 30-day and 1-year mortality following coronary artery bypass surgery.

OBJECTIVE: The purpose of this study was to examine the effect of peri-operative red blood cell (RBC) transfusion on 30-day and 1-year mortality following coronary artery bypass grafting (CABG). METHODS: We retrospectively analysed 3024 consecutive patients who underwent isolated CABG between January 1999 and December 2001. Patient records were linked to the National Strategic Tracing Service, which records all mortality in the UK. Thirty-day and 1-year mortality were derived from Kaplan-Meier curves. Confounding variables were controlled for by constructing a propensity score for the probability of receiving a transfusion from core patient characteristics including the lowest recorded laboratory haemoglobin (LL Hb) from a clinical chemistry database (C statistic 0.81). The propensity score and the comparison variable (transfusion versus no transfusion) were included in a Cox proportional hazards analysis, allowing calculation of adjusted hazard ratios (HR) and Kaplan-Meier survival curves. RESULTS: Nine hundred and forty (31.1%) patients received RBC transfusion during or within 72h of surgery. Predictors of the need for transfusion were LL Hb and lower body mass index, use of cardiopulmonary bypass, female sex, number of grafts, renal dysfunction, increased age, extent of disease, and prior CABG; these factors were all included in the propensity score. After 1-year of follow-up, 122 (4.03%) deaths occurred. The crude HR for 1-year mortality in patients transfused was 3.0 (P<0.001). After adjusting for the propensity score, re-operation for bleeding, peri-operative blood loss and post-operative complications, the adjusted 30-day mortality was 1.9% in transfused patients compared to 1.1% in patients not transfused (P<0.05). The adjusted HR for 1-year mortality in patients transfused was 1.88 (P<0.01). CONCLUSIONS: Peri-operative RBC transfusion after CABG is associated with an increased risk of mortality during a 1-year follow-up period, with a large proportion of deaths occurring within 30-days.

Bacteremia following complex percutaneous coronary intervention.

BACKGROUND AND OBJECTIVE: Complex percutaneous coronary intervention (PCI) often requires introduction of numerous devices into and out of the arterial circulation and this may result in an increased risk of bacteraemia or even septicaemia. This study was undertaken to detect the frequency of bacteraemia that may be associated with such procedures. METHODS: 147 patients undergoing complex PCI had blood culture tests immediately after and 12 hours after the procedure. RESULTS: Of 147 patients, 26 (17.7%) had detectable bacteraemia immediately after PCI. Coagulase-negative staphylococcus was isolated most commonly. An additional 12% of patients yielded positive blood cultures in the next 12 hours with femoral sheaths still in-situ. There were no associated clinical sequelae. CONCLUSIONS: Uncomplicated bacteraemia is not uncommon as a result of complex PCI procedures. Although there are usually no clinical sequelae, these findings are important for those patients who are considered to be at moderate or high risk of infective endocarditis who require an invasive procedure such as PCI. This paper emphasizes the need for maximum sterility during PCI procedures if infective complications and stent infection are to be avoided.

Treatment of superior vena caval obstruction following permanent pacemaker extraction.

Superior vena caval (SVC) obstruction following permanent pacemaker lead extraction is a serious but uncommon complication. This report describes the case of an 83-year-old man treated by balloon angioplasty and femoral pacemaker implantation.