António Miguel Ferreira

Left atrial volume calculated by multi-detector computed tomography may predict successful pulmonary vein isolation in catheter ablation of atrial fibrillation

AIMS Catheter ablation (CA) of atrial fibrillation (AF) might be a definitive curative therapy for selected groups of patients (pts). However, current ablation protocols are not standardized and predictors of CA success and sinus rhythm maintenance are not clearly defined. To evaluate whether left atrium (LA) volume quantification provided by multi-detector computed tomography (MDCT) might predict the success of pulmonary vein (PV) isolation procedure. METHODS AND RESULTS We evaluated 99 pts, 66 male, mean age 54.4 +/- 10.1 years, referred for CA because of drug resistant AF. All pts were submitted to 64-slice MDCT scan for electroanatomic mapping integration, pulmonary veins anatomy delineation, LA thrombi exclusion, and LA volume estimation. Complete isolation of all the PVs was always performed with eventual cavo-tricuspid isthmus ablation. For a mean follow-up period (Fup) of 16.7 +/- 6.6 months, clinical success was assessed after a 3-month blanking period. Anti-arrhythmic drug therapy was discontinued or modified at the clinicians criteria. At the end of the Fup, 29 pts suspended anti-arrhythmic drug therapy and 26% were of oral anticoagulation. Univariate analysis showed that the probability of AF relapse after CA was higher in pts with non-paroxysmal forms of AF. The probability of relapse was significantly higher in pts with LA volumes greater than 100 mL when assessed by MDCT. We found that the LA volume of 145 mL was a good cut-off value for AF recurrence prediction. Patients with LA volumes greater than 145 mL had significantly higher recurrence rates of arrhythmia, even when adjusted for the effect of age, gender, body mass index, hypertension, and type of AF. CONCLUSION Left atrium volume estimated by MDCT may be useful to identify pts in whom successful AF ablation can be achieved with simpler ablation procedures, restricted to PV isolation.

Benefit of cardiac resynchronization therapy in atrial fibrillation patients vs. patients in sinus rhythm: the role of atrioventricular junction ablation

AIMS To assess the clinical benefit of cardiac resynchronization therapy (CRT) in patients with atrial fibrillation (AF) compared with patients in sinus rhythm (SR), and to evaluate the impact of atrioventricular junction (AVJ) ablation on the outcome of AF patients undergoing CRT. METHODS AND RESULTS We conducted a retrospective analysis of 131 consecutive heart failure (HF) patients who underwent CRT implantation. Three groups were considered: SR (n = 78), AF with AVJ ablation (n = 26), and AF without AVJ ablation (n = 27). Patients were evaluated for the occurrence of cardiac death, hospitalization for HF, and responsiveness to CRT (survival with improvement of >or=1 New York Heart Association class at 6 months). The three groups showed a significant improvement in functional class. However, the proportion of responders was significantly lower in AF patients without AVJ ablation (52 vs. 79% in SR and 85% in AF with AVJ ablation, P < 0.008). Atrial fibrillation without AVJ ablation was also independently associated with mortality (HR 5.22, 95% CI: 1.60-17.01, P = 0.006) and hospitalization for HF during the first 12 months (HR 6.23, 95% CI: 2.09-18.54, P = 0.001). The outcomes of AF with AVJ ablation patients were similar to the outcomes of patients in SR. CONCLUSION Sinus rhythm and AF patients display similar survival and clinical improvement after CRT implantation, provided that AVJ ablation is performed in the latter.

Ventilatory Efficiency and the Selection of Patients for Heart Transplantation

Background—Ventilatory efficiency, assessed by the slope of minute ventilation (Ve) versus carbon dioxide production (Vco2), is a powerful prognostic marker in patients with chronic heart failure. We hypothesized that Ve/Vco2 slope would be more accurate than the current listing criteria for heart transplantation (HTx) in identifying patients likely to derive a survival benefit from this intervention. Methods and Results—A total of 663 patients with chronic heart failure who underwent cardiopulmonary exercise testing were tracked for cardiac mortality and HTx. Ve/Vco2 slope was the strongest independent predictor of mortality. Using a Ve/Vco2 slope threshold instead of the current exercise criteria would classify 39 more subjects as being high risk (196 versus 157), correctly identifying 19 more patients who died during follow-up (57 versus 38) and 16 others who underwent transplantation (52 versus 36). Unlike the current listing criteria for HTx, Ve/Vco2 slope provided significant discrimination between the 3-year survival of high- and low-risk patients and posttransplant patients selected from the International Society for Heart and Lung Transplantation registry. Reanalysis of survival data using death or HTx as the end point showed similar results. Conclusions—Ve/Vco2 slope is more accurate than the current listing criteria for HTx in identifying patients likely to derive a survival benefit from HTx.

Left atrial volume is more important than the type of atrial fibrillation in predicting the long-term success of catheter ablation

BACKGROUND The type of atrial fibrillation (AF) is the sole prognostic factor that affects the level of recommendation for catheter ablation in the current guidelines. Despite being recognized as a predictor of recurrence, relatively little emphasis is given to left atrium (LA) size. The aim of this study was to assess the relative importance of LA volume and type of AF as predictors of outcome after PVI. METHODS We assessed 809 consecutive patients with symptomatic drug-refractory AF (584 male, mean age 57 ± 11 years) undergoing 905 percutaneous PVI procedures in two centers. LA volume was assessed by cardiac CT and/or electroanatomical mapping prior to AF ablation. The study endpoint was symptomatic and/or documented AF recurrence. RESULTS The majority of patients (73.2%, n=592) had paroxysmal AF. The mean indexed LA volume was 55 ± 20 ml/m(2). During a follow-up of 2.4 ± 1.7 years, there were 280 recurrences. The relapse rate of patients with paroxysmal AF in the highest tertile of LA volume was higher than the relapse rate of patients with non-paroxysmal AF in the lowest tertile (20.0% vs. 10.9% per person-year, respectively, p=0.041). LA volume (HR 1.16 for each 10 ml/m(2), 95% CI 1.09-1.23, p<0.001), female gender (HR 1.55, 95% CI 1.19-2.03, p=0.001), and non-paroxysmal AF (HR 1.31, 95% CI 1.01-1.69, p=0.039) were the only independent predictors of AF recurrence. Split-sample cross-validation resampling confirmed LA volume as the strongest predictor of relapse after PVI. CONCLUSION Left atrial volume seems to be more important than the type of atrial fibrillation in predicting the long-term success of pulmonary vein isolation.

Does continuous ST-segment monitoring add prognostic information to the TIMI, PURSUIT, and GRACE risk scores?

Background: Recurrent ischemia is frequent in patients with non‐ST‐elevation acute coronary syndromes (NST‐ACS), and portends a worse prognosis. Continuous ST‐segment monitoring (CSTM) reflects the dynamic nature of ischemia and allows the detection of silent episodes. The aim of this study is to investigate whether CSTM adds prognostic information to the risk scores (RS) currently used.

Cost-Effectiveness of Different Diagnostic Strategies in Suspected Stable Coronary Artery Disease in Portugal

Background Cost-effectiveness is an increasingly important factor in the choice of a test or therapy. Objective To assess the cost-effectiveness of various methods routinely used for the diagnosis of stable coronary disease in Portugal. Methods Seven diagnostic strategies were assessed. The cost-effectiveness of each strategy was defined as the cost per correct diagnosis (inclusion or exclusion of obstructive coronary artery disease) in a symptomatic patient. The cost and effectiveness of each method were assessed using Bayesian inference and decision-making tree analyses, with the pretest likelihood of disease ranging from 10% to 90%. Results The cost-effectiveness of diagnostic strategies was strongly dependent on the pretest likelihood of disease. In patients with a pretest likelihood of disease of ≤50%, the diagnostic algorithms, which include cardiac computed tomography angiography, were the most cost-effective. In these patients, depending on the pretest likelihood of disease and the willingness to pay for an additional correct diagnosis, computed tomography angiography may be used as a frontline test or reserved for patients with positive/inconclusive ergometric test results or a calcium score of >0. In patients with a pretest likelihood of disease of ≥ 60%, up-front invasive coronary angiography appears to be the most cost-effective strategy. Conclusions Diagnostic algorithms that include cardiac computed tomography angiography are the most cost-effective in symptomatic patients with suspected stable coronary artery disease and a pretest likelihood of disease of ≤50%. In high-risk patients (pretest likelihood of disease ≥ 60%), up-front invasive coronary angiography appears to be the most cost-effective strategy. In all pretest likelihoods of disease, strategies based on ischemia appear to be more expensive and less effective compared with those based on anatomical tests.

Body mass index as a predictor of the presence but not the severity of coronary artery disease evaluated by cardiac computed tomography

Background The relation between body mass index (BMI) and coronary artery disease (CAD) extension remains controversial. The aim of this study was to evaluate the correlation between BMI and CAD extension documented by coronary computed tomography angiography (CCTA). Methods and results Prospective registry including 1706 consecutive stable patients that performed CCTA (dual source scanner) for the evaluation of CAD. The population was stratified by BMI: normal 530 (31.1%), overweight 802 (47.0%) and obesity 374 (21.9%). BMI was significantly higher in patients with CAD (27.7 ± 4.3 vs 26.8 ± 4.3 kg/m2, p < 0.001); these patients were also older, more often male and had higher prevalence of diabetes, hypertension and dyslipidemia. By multivariate analysis (logistic regression) BMI remains an independent predictor of CAD (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.01–1.06; p = 0.012). Regarding the severity of CAD, BMI was not significantly different among patients with and without obstructive CAD (27.7 ± 4.3 vs 27.2 ± 4.3 kg/m2, p = 0.120). In 319 patients (4516 segments; 4077 evaluable), a detailed atherosclerotic burden was evaluated and compared among BMI classes, defined according to the presence of plaque and the degree of stenosis. Obstructive CAD was identified in 16.9% of the patients and 45.1% had non-obstructive CAD. The discriminative threshold for high burden, established by the segment involvement score (SIS), was >5 segments with plaque (15.4% patients). The prevalence of SIS >5 among the BMI classes was: 18.7%, 13.7% and 13.6% for normal, overweight and obesity respectively (p values for the specific classes versus all other patients: 0.241, 0.450 and 0.663). Conclusions In this population of stable patients undergoing CCTA for suspected CAD, BMI was an independent predictor of its presence, but was not correlated with the coronary disease severity.

Diagnostic yield of current referral strategies for elective coronary angiography in suspected coronary artery disease—An analysis of the ACROSS registry

INTRODUCTION AND OBJECTIVES The purpose of this study was to assess the diagnostic yield of current referral strategies for elective invasive coronary angiography (ICA). METHODS We performed a cross-sectional observational study of consecutive patients without known coronary artery disease (CAD) undergoing elective ICA due to chest pain symptoms. The proportion of patients with obstructive CAD (defined as the presence of at least one ≥50% stenosis on ICA) was determined according to the use of noninvasive testing. RESULTS The study population consisted of 1892 individuals (60% male, mean age 64±11 years), of whom 1548 (82%) had a positive noninvasive test: exercise stress test (41%), stress myocardial perfusion imaging (36%), stress echocardiogram (3%) or coronary computed tomography angiography (3%). Referral without testing occurred in 18% of patients. The overall prevalence of obstructive CAD was 57%, higher among those with previous testing (58% vs. 51% without previous testing, p=0.026) and when anatomic rather than functional tests were used (81.3% vs. 57.1%, p=0.001). A positive test and conventional risk factors were all independent predictors of obstructive CAD, with adjusted odds ratios (95% confidence interval) of 1.34 (1.03-1.74) for noninvasive testing, 1.05 (1.04-1.06) for age, 3.48 (2.81-4.29) for male gender, 1.86 (1.32-2.62) for current smoking, 1.74 (1.38-2.20) for diabetes, 1.30 (1.04-1.62) for hypercholesterolemia, and 1.39 (1.08-1.80) for hypertension. CONCLUSIONS More than 40% of patients without known CAD undergoing elective ICA did not have obstructive lesions, even though four out of five had a positive noninvasive test. These exams were relatively weak gatekeepers; functional tests were more often used but appeared to be outperformed by the anatomic test.

Development and validation of a risk score for predicting atrial fibrillation recurrence after a first catheter ablation procedure: ATLAS score—Author’s reply

Aims Several predictors of relapse after catheter ablation of atrial fibrillation (AF) have been established, but assessing each patients individual risk remains challenging. Our aim was to develop and validate a score to estimate the risk of AF recurrence after the first radiofrequency pulmonary vein isolation (PVI) procedure. Methods and results Independent predictors of AF relapse were identified retrospectively in a two-centre registry of 1934 patients who underwent a first PVI procedure. Using the Cox regression hazard ratios of designated variables, a risk score was developed in a random sample of 50% of the patients (development cohort) and validated in the remaining (validation cohort) half. The accuracy and discriminative power of the predictive model were assessed in both subgroups. During a follow-up of 4.2 ± 2.7 years, 522 patients (27%) relapsed. Five independent predictors of AF recurrence were identified and included in the score: age >60 years (1 point), female sex (4 points), non-paroxysmal AF (2 points), current smoking (7 points) and indexed left atrial volume (1 point for each 10 mL/m2). The score showed good discriminative power (censored c-statistic of 0.75 in both cohorts). In the development group, AF relapse rates were 8, 11, and 17%/year for low (<6 points), intermediate (6-10 points), and high-risk patients (>10 points), respectively (P < 0.001). In the validation group, AF recurrence rates were 8, 11, and 18%/year, respectively (P < 0.001). Conclusion A simple risk score to estimate the rate of AF recurrence after ablation was developed and validated. An external assessment of its usefulness as a patient selection tool seems warranted.

Defining the Place of Ezetimibe/Atorvastatin in the Management of Hyperlipidemia

Statin–ezetimibe combinations are a potentially advantageous therapeutic option for high-risk patients who need additional lowering of low-density lipoprotein cholesterol (LDL-C). These combinations may overcome some of the limitations of statin monotherapy by blocking both sources of cholesterol. Recently, a fixed-dose combination with atorvastatin, one of the most extensively studied statins, was approved and launched in several countries, including the USA. Depending on atorvastatin dose, this combination provides LDL-C reductions of 50–60%, triglyceride reductions of 30–40%, and high-density lipoprotein cholesterol (HDL-C) increases of 5–9%. Studies comparing the lipid-lowering efficacy of the atorvastatin–ezetimibe combination with the alternatives of statin dose titration or switching to a more potent statin consistently showed that combination therapy provided greater LDL-C reduction, translating into a greater proportion of patients achieving lipid goals. Simvastatin–ezetimibe combinations have been shown to reduce the incidence of major atherosclerotic events in several clinical settings to a magnitude that seems similar to that observed with statins for the same degree of absolute LDL-C lowering. The atorvastatin–ezetimibe combination has also been shown to induce the regression of coronary atherosclerosis measured by intravascular ultrasound in a significantly greater proportion of patients than atorvastatin alone. Atorvastatin–ezetimibe combinations are generally well tolerated. Previous concerns of a possible increase in the incidence of cancer with ezetimibe were dismissed in large trials with long follow-up periods. In this paper, we examine the rationale for an atorvastatin–ezetimibe combination, review the evidence supporting it, and discuss its potential role in the management of dyslipidemia.