Dobutamine stress echocardiography after cardiac transplantation: implications of donor-recipient age difference.

Dobutamine stress echocardiography (DSE) is widely used during follow-up after cardiac transplant for the diagnosis of allograft vasculopathy. We investigated the effect of donor-recipient age difference on the ability to reach target heart rate (HR) during DSE. All cardiac transplant patients who were undergoing DSE over a 3-year period in a single institution were reviewed. Target HR was specified as 85%×(220 - patient age). Further patient and donor demographics were obtained from the local transplant database. 61 patients (45 male, 55±12 years) were stressed with a median dose of 40 mcg/kg per min dobutamine. Only 37 patients (61%) achieved target HR. Donor hearts were mostly younger (mean 41±14 years, P<0.001), with only 11 patients (18%) having donors who were older than they were. Patients with older donors required higher doses of dobutamine (median 50 vs 30 mcg/kg per min, P<0.001) but achieved a lower percentage target HR (mean 93% vs 101%, P=0.003) than those with younger donors did. Patients with older donors were less likely to achieve target HR (18% vs 67%, P=0.003). In conclusion, donor-recipient age difference affects the likelihood of achieving target HR and should be considered when a patient is consistently unable to achieve 'adequate' stress according to the patient's age.

Classification of left ventricular size: diameter or volume with contrast echocardiography?

BACKGROUND: Left ventricular (LV) size is an important clinical variable, commonly assessed at echocardiography by measurement of the internal diameter in diastole (IDD). However, this has recognised limitations and volumetric measurement from apical views is considered superior, particularly with the use of echocardiographic contrast. We sought to determine the agreement in classification of LV size by different measures in a large population of patients undergoing echocardiography. METHODS AND RESULTS: Data were analysed retrospectively from consecutive patients (n=2008, 61% male, median 62 years) who received echocardiographic contrast for LV opacification over 3 years in a single institution. Repeat studies were not included. LVIDD was measured, and LV end-diastolic volume (LVEDV) calculated using Simpson's biplane method. Both measures were indexed (i) to body surface area and categorised according to the American Society of Echocardiography (ASE) guidelines as normal, mild, moderate or severely dilated. Of 320 patients with a severely dilated LVEDVi, only 95 (30%) were similarly classified by LVIDD, with 86 patients (27%) measuring in the normal range. LVIDDi agreement was poorer, with only 43 patients (13%) classified as being severely dilated, and 173 (54%) measuring in the normal range. CONCLUSIONS: Currently recommended echocardiographic measures of LV size show limited agreement when classified according to currently recommended cut-offs. LV diameter should have a limited role in the assessment of LV size, particularly where a finding of LV dilation has important diagnostic or therapeutic implications.

Hypertrophic cardiomyopathy with intermittent free mitral regurgitation-a surgical dilemma.

We describe the case of a 52-year-old woman presenting with non-ST elevation myocardial infarction, atrial fibrillation, and a new diagnosis of hypertrophic cardiomyopathy. Transesophageal echocardiography following hemodynamic deterioration revealed completely restricted mitral leaflet motion with free mitral regurgitation, and severe left ventricular outflow tract (LVOT) obstruction. Surgical intervention was considered; however, repeat imaging following a period of clinical stability revealed resolution of the findings suggesting a transient ischemic etiology. The case is supported by clinical and echocardiographic images with movie clips, and a discussion of the likely pathology in the context of the underlying condition.

Single sweep three-dimensional carotid ultrasound: reproducibility in plaque and artery volume measurements.

BACKGROUND: There is a need for non-invasive and accurate techniques for assessment of severity of atherosclerotic disease in the carotid arteries. Recently an automated single sweep three-dimensional ultrasound (3D US) technique became available. The aims of this study were to evaluate the feasibility and reproducibility of the automated single sweep method in a cohort of patients undergoing clinically indicated carotid ultrasound. METHODS: Consecutive patients with a history of stroke or transient ischemic attack (TIA) and having a plaque in the internal carotid artery (ICA) were recruited for this study. Imaging was performed using a Philips iU 22 ultrasound system equipped with the single sweep volumetric transducer vL 13-5. Analysis was performed offline with software provided by the manufacturer. Two independent observers performed all measurements. RESULTS: Of 137 arteries studied (from 79 patients), plaque and artery volumes could be measured in 106 (77%). Reproducibility of plaque volume measurements was assessed in 82 arteries. Bland-Altman analysis demonstrated good inter-observer reproducibility with limits of agreement -0.06 to +0.07 ml. The mean percentage difference between two observers was 5.6% ± 6.0%. Reproducibility of artery volume measurement was assessed in 31 cases. Bland-Altman analysis demonstrated limits of agreement from -0.15 to +0.15 ml. The mean percentage difference was 6.4 ± 5.9%. CONCLUSION: The new automated single sweep 3D ultrasound is feasible in the majority of patients. Good reproducibility in plaque and artery volume measurements makes this technique suitable for serial assessment of carotid plaques.

Three-dimensional echocardiography in a dynamic heart phantom: comparison of five different methods to measure chamber volume using a commercially available software.

Several methods of analysis are available for quantification of left ventricular volumes and ejection fraction using three-dimensional (3D) echocardiography. This study compared the accuracy and reproducibility of five methods of analysis in a novel, irregularly shaped dynamic heart phantom with excellent image quality. Five 3D datasets were acquired on a Philips IE33 platform using an X5-1 3D transducer. Each dataset was analysed by five different methods using the Philips QLab v8.1 software: Methods A1, A2 and A3, semi-automated contour detection with varying degrees of user correction; Method B, Simpson's biplane method using optimally aligned four- and two-chamber views and Method C, method of discs, manually delineated in reconstructed short-axis views. Time-volume curves were generated for each method and compared with the true volumes measured throughout systole in the phantom heart. A second observer repeated measurements by each method in a single 3D dataset. Method A1 (uncorrected semi-automated contouring) produced the most consistent time-volume curves, although end-diastolic and end-systolic volumes varied between datasets. Any manual correction of contours (Methods A2, A3 and B) resulted in significant variation in the time-volume curves, with less consistent endocardial tracking. Method C was not only the most accurate and reproducible method, but also the most time-consuming one. Different methods of 3D volume quantification vary significantly in accuracy and reproducibility using an irregular phantom heart model. Although contouring may appear optimal in long-axis views, this may not be replicated circumferentially, and the resulting measures appeared to be less robust following the manual correction of semi-automated contours.

Adverse psychological effects and costs associated with waiting for radiofrequency ablation.

BACKGROUND: Radiofrequency ablation (RFA) is undertaken as a potentially curative treatment for a variety of heart rhythm disturbances. Previous studies have demonstrated improved quality of life and reduced symptoms after ablation. In many health care environments waiting lists exist for scheduling of procedures. However, the psychological effects of waiting for radiofrequency ablation have not previously been assessed. We hypothesized that waiting for this intervention may be associated with increased psychological morbidity and health care costs. METHODS: Ninety-two patients scheduled for elective RFA completed repeated questionnaires comprising the Medical Outcomes Short Form 36, Hospital Anxiety and Depression Scale, and an in-house questionnaire designed to assess the burden of symptoms related to arrhythmia (arrhythmia-related burden score). Mean scores were generated and compared at time points while waiting, before and after the procedure. Regression analyses were carried out to identify predictors of increased psychological morbidity while waiting and immediately prior to the procedure. Health care costs during the waiting period as a consequence of arrhythmia were quantified. RESULTS: Mean scores for parameters of psychological morbidity worsened during the period of waiting and improved after the procedure. Predictors of adverse effects within the cohort varied according to the time point assessed for each of the measures of psychological morbidity. A conservative estimate of the health care cost incurred while waiting exceeds £ 181 per patient. CONCLUSIONS: Waiting for radiofrequency ablation appears to be associated with adverse psychological effects and health care costs. These results may support strategies to reduce waiting times and prioritize resource allocation.

Keeping track of congenital heart disease--is it time for a national registry?

Considerable improvements have been made in care and provision for patients with congenital heart disease in the United Kingdom. However, delayed presentation of adult patients with sequelae of known childhood cardiac defects reflects the current situation that there is no national registry of patients with congenital heart disease, and this "lost cohort" of patients is difficult to trace. Maintaining regular follow-up for selected patients with congenital heart disease can be challenging for a variety of reasons, but remains particularly important as emerging therapies and treatment strategies continue to alter management. Despite recent calls from a variety of organisations to establish a national registry of patients with congenital heart disease, progress has been slow. Faced with competition for resources, the costs of such a venture may be cited as a likely hurdle, but the potential advantages for patients and healthcare providers alike justify calls to integrate a registry as part of the ongoing reorganisation of congenital heart services in the United Kingdom.

Usefulness of neutrophil/lymphocyte ratio as predictor of new-onset atrial fibrillation after coronary artery bypass grafting.

The neutrophil/lymphocyte (N/L) ratio integrates information on the inflammatory milieu and physiologic stress. It is an emerging marker of prognosis in patients with cardiovascular disease. We investigated the relation between the N/L ratio and postoperative atrial fibrillation (AF) in patients undergoing coronary artery bypass grafting. In a prospective cohort study, 275 patients undergoing nonemergency coronary artery bypass grafting were recruited. Patients with previous atrial arrhythmia or requiring concomitant valve surgery were excluded. The N/L ratio was determined preoperatively and on postoperative day 2. The study end point was AF lasting >30 seconds. Patients who developed AF (n = 107, 39%) had had a greater preoperative N/L ratio (median 3.0 vs 2.4, p = 0.001), but no differences were found in the other white blood cell parameters or C-reactive protein. The postoperative N/L ratio was greater in patients with AF (day 2, median 9.2 vs 7.2, p <0.001), and in multivariate models, a greater postoperative N/L ratio was independently associated with a greater incidence of AF (odds ratio 1.10 per unit increase, p = 0.003: odds ratio for N/L ratio >10.14 [optimal postoperative cutoff in our cohort], 2.83 per unit, p <0.001). Elevated pre- and postoperative N/L ratios were associated with an increased occurrence of AF after coronary artery bypass grafting. In conclusion, these results support an inflammatory etiology in postoperative AF but suggest that other factors are also important.

Use of preoperative natriuretic peptides and echocardiographic parameters in predicting new-onset atrial fibrillation after coronary artery bypass grafting: a prospective comparative study.

BACKGROUND: Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting (CABG). We prospectively compared the ability of echocardiographic parameters and the cardiac neurohormones, brain natriuretic peptide (BNP), and N-terminal pro-brain natriuretic peptide (NT-proBNP) to predict AF in this setting. METHODS: We recruited 275 patients undergoing nonemergency CABG. Patients undergoing valve surgery or with prior atrial dysrhythmia (based on clinical history and review of medical records) were excluded. Echocardiography was performed, and natriuretic peptide levels were measured, 24 hours before surgery. The primary end point was postoperative AF lasting >30 seconds. RESULTS: The only significant echocardiographic predictors of postoperative AF (n = 107, 39%) were the transmitral E to A-wave ratio and the early mitral annulus velocity. Levels of BNP and NT-proBNP were higher in patients who developed AF. Both natriuretic peptides, but none of the echocardiographic parameters, remained independently predictive in multivariable analysis. The optimum cut points for predicting AF were 31 pg/mL for BNP (odds ratio [OR] 2.74, P = .001) and 74 pg/mL for NT-proBNP (OR 2.74, P = .003). CONCLUSION: Levels of BNP and NT-proBNP are independent, though modestly effective, predictors of AF after isolated CABG. In contrast, none of the echocardiographic parameters assessed, including measures of LV systolic function and filling pressure, were independently predictive.

Uric acid levels and outcome from coronary artery bypass grafting.

OBJECTIVE: Elevated uric acid levels have been associated with an adverse cardiovascular outcome in several settings. Their utility in patients undergoing surgical revascularization has not, however, been assessed. We hypothesized that serum uric acid levels would predict the outcome of patients undergoing coronary artery bypass grafting. METHODS: The study cohort consisted of 1140 consecutive patients undergoing nonemergency coronary artery bypass grafting. Clinical details were obtained prospectively, and serum uric acid was measured a median of 1 day before surgery. The primary end point was all-cause mortality. RESULTS: During a median of 4.5 years, 126 patients (11%) died. Mean (+/- standard deviation) uric acid levels were 390 +/- 131 micromol/L in patients who died versus 353 +/- 86 micromol/L among survivors (hazard ratio 1.48 per 100 micromol/L; 95% confidence interval, 1.25-1.74; P < .001). The excess risk associated with an elevated uric acid was particularly evident among patients in the upper quartile (>or=410 micromol/L; hazard ratio vs all other quartiles combined 2.18; 95% confidence interval, 1.53-3.11; P < .001). After adjusting for other potential prognostic variables, including the European System for Cardiac Operative Risk Evaluation, uric acid remained predictive of outcome. CONCLUSION: Increasing levels of uric acid are associated with poorer survival after coronary artery bypass grafting. Their prognostic utility is independent of other recognized risk factors, including the European System for Cardiac Operative Risk Evaluation.

The relationship between renal function and outcome from heart valve surgery.

BACKGROUND: The prognostic importance of renal function in patients undergoing surgery for valvular heart disease is poorly defined. The current study addresses this issue. METHODS: Baseline demographic and clinical variables, including the European system for cardiac operative risk evaluation (EuroSCORE), were recorded prospectively from 514 consecutive patients undergoing heart valve surgery between April 2000 and March 2004. Patients with active infective endocarditis and/or requiring emergency surgery were excluded. The glomerular filtration rate was estimated (eGFR) using the Modification of Diet in Renal Disease equation. The primary outcome was all-cause mortality. RESULTS: During a median follow-up of 2 years, 87 patients died. In univariable analysis, both eGFR (hazard ratio [HR] 0.69 per 10 mL/min per 1.73 m2, P<.001) and creatinine (HR 1.04 per 10 micromol/L, P<.001) predicted mortality. Estimated GFR was a stronger predictor and was used in subsequent multivariable models. It remained a powerful independent predictor of death in a multivariable model including all study variables (HR 0.70 per 10 mL/min per 1.73 m2 increase, P<.001) and in a model including EuroSCORE (HR 0.64 per 10 mL/min per 1.73 m2 increase, P<.001). After correction for preoperative EuroSCORE, an eGFR of <60 mL/min per 1.73 m2 was associated with an excess hazard of death of 2.31 (P=.001). CONCLUSION: Renal function, particularly the eGFR, is a powerful predictor of outcome in patients undergoing heart valve surgery. This prognostic utility is independent of other recognized risk factors and the EuroSCORE.

Preoperative neutrophil-lymphocyte ratio and outcome from coronary artery bypass grafting.

BACKGROUND: An elevated preoperative white blood cell count has been associated with a worse outcome after coronary artery bypass grafting (CABG). Leukocyte subtypes, and particularly the neutrophil-lymphocyte (N/L) ratio, may however, convey superior prognostic information. We hypothesized that the N/L ratio would predict the outcome of patients undergoing surgical revascularization. METHODS: Baseline clinical details were obtained prospectively in 1938 patients undergoing CABG. The differential leukocyte was measured before surgery, and patients were followed-up 3.6 years later. The primary end point was all-cause mortality. RESULTS: The preoperative N/L ratio was a powerful univariable predictor of mortality (hazard ratio [HR] 1.13 per unit, P < .001). In a backward conditional model, including all study variables, it remained a strong predictor (HR 1.09 per unit, P = .004). In a further model, including the European system for cardiac operative risk evaluation, the N/L ratio remained an independent predictor (HR 1.08 per unit, P = .008). Likewise, it was an independent predictor of cardiovascular mortality and predicted death in the subgroup of patients with a normal white blood cell count. This excess hazard was concentrated in patients with an N/L ratio in the upper quartile (>3.36). CONCLUSION: An elevated N/L ratio is associated with a poorer survival after CABG. This prognostic utility is independent of other recognized risk factors.

Relationship between postoperative cardiac troponin I levels and outcome of cardiac surgery.

BACKGROUND: Cardiac surgery may be associated with significant perioperative and postoperative morbidity and mortality. Underlying pathology, surgical technique, and postoperative complications may all influence outcome. These factors may be reflected as a rise in postoperative troponin levels. Interpretation of troponin levels in this setting may therefore be complex. This study assessed the prognostic significance of such measurements, taking into account potential confounding variables. METHODS AND RESULTS: One-thousand three hundred sixty-five patients undergoing cardiac surgery underwent measurement of cardiac troponin I (cTnI) at 2 and 24 hours after surgery. The relationship of these measurements to subsequent mortality was established. After taking into account all other variables, cTnI levels measured at 24 hours were independently predictive of mortality at 30 days (odds ratio [OR] 1.14 per 10 microg/L, 95% confidence interval [CI] 1.05 to 1.24, P=0.002), 1 year (OR 1.10 per 10 microg/L, 95% CI 1.03 to 1.18, P=0.006), and 3 years (OR 1.07 per 10 microg/L, 95% CI 1.00 to 1.15, P=0.04). Cardiac TnI levels in the highest quartile at 24 hours were associated with a particularly poor outcome. CONCLUSIONS: cTnI levels measured 24 hours after cardiac surgery predict short-, medium-, and long-term mortality and remain independently predictive when adjusted for all other potentially confounding variables, including operation complexity.