Summary
Background
The distribution of left ventricular ejection fraction (LVEF) – a key factor in coronary artery disease (CAD) patient management and prognostication – is poorly documented.
Objective
To determine LVEF and heart rate (HR) values, and describe the management of stable CAD patients in France.
Methods
The INDYCE survey was a prospective, multicentre registry of consecutive stable CAD outpatients attending a cardiology consultation. The survey focused on LVEF values measured using the echocardiographic Simpson biplane method. Drug therapy, resting HR, blood pressure and symptoms were also recorded.
Results
Overall, 3119 patients (68.4 ± 11.0 years; 80% men) were enrolled. LVEF was 56.1 ± 11.8% on average, and was poor (< 40%) and moderately impaired (40–50%) in 9.6% ( n = 298) and 19.8% ( n = 619) of cases, respectively. Symptomatic angina pectoris was present in 19.2% of cases and only 40.6% of patients were asymptomatic (no angina and NYHA class ≤ I) despite relatively aggressive management (79.0% of patients had undergone coronary angioplasty and/or bypass graft). Interestingly, 14.1% of patients with LVEF less than 40% were asymptomatic. In multivariable analysis, LVEF less than 40% was associated most strongly with symptomatic status (odds ratio 3.82; 95% CI 2.59–5.63; P < 0.0001), together with female sex, age greater than 75 years, diabetes, HR greater or equal to 70 bpm, sedentariness, obesity and disease duration.
Conclusion
Only 9.6% of stable CAD patients had severe left ventricular dysfunction; among them, 14.1% were strictly asymptomatic. This could justify regular LVEF measurement in CAD patients. Three potentially reversible factors (HR ≥ 70 bpm, being overweight and sedentariness) were linked independently to the presence of symptoms.
Résumé
État des lieux
La prise en charge et l’évaluation du pronostic des patients coronariens stables sont en grande partie basées sur la fraction d’éjection ventriculaire gauche (FEVG), mais la distribution de celle-ci chez ces patients est peu documentée.
Objectifs
Décrire la distribution des valeurs de FEVG et de fréquence cardiaque de repos (Fc) ainsi que la prise en charge des patients coronariens stables en France.
Méthodes
Le registre INDYCE multicentrique et prospectif a inclus consécutivement les patients coronariens stables vus en consultation externe de cardiologie. L’objectif principal était la mesure de la FEVG par la méthode de Simpson Biplan. Le traitement, la Fc, la pression artérielle et la symptomatologie étaient aussi analysés.
Résultats
Au total, 3119 patients (âge moyen : 68,4 ± 11,0 ans ; 80 % d’hommes) ont été inclus. La FEVG était de 56,1 ± 11,8 % ; la fonction systolique ventriculaire gauche était sévèrement (FEVG < 40 %) ou modérément (40–50 %) altérée chez respectivement 9,6 % ( n = 298) et 19,8 % ( n = 619) des patients. Le pourcentage de patients qui souffraient d’angor était de 19,2 % et seulement 40,6 % d’entre eux étaient strictement asymptomatiques (pas d’angor et classe NYHA ≤ 1) malgré une prise en charge assez agressive (79,0 % des patients ayant bénéficié d’au moins une procédure de revascularisation). On note que 14,1 % des patients avec une FEVG inférieure à 40 % étaient asymptomatiques. En analyse multivariée, l’existence d’une FEVG inférieure à 40 % était le facteur le plus fortement associé à l’existence de symptômes (OR 3,82 ; IC 95 % : 2,59 à 5,63 ; p < 0,0001), les autres paramètres étant le sexe féminin, l’âge supérieur à 75 ans, le diabète, une Fc supérieure ou égale à 70 bpm, la sédentarité, l’obésité et l’ancienneté de la maladie angineuse.
Conclusion
Le pourcentage de patients coronariens stables présentant une dysfonction ventriculaire gauche sévère est de 9,6% ; parmi eux, 14,1 % sont strictement asymptomatiques, ce qui pourrait justifier une mesure régulière de la FEVG chez l’ensemble des coronariens. Seulement trois facteurs potentiellement réversibles (obésité, sédentarité et Fc ≥ 70 bpm) sont associés à l’existence de symptômes.
Abbreviations
bpm
beats per minute
CAD
coronary artery disease
HR
heart rate
LVEF
left ventricular ejection fraction
NYHA
New York Heart Association
OR
odds ratio
Background
Discovery of systolic left ventricular dysfunction is a key event in the course of stable coronary artery disease (CAD). Indeed, it worsens the prognosis and often requires changes in patient management, including escalation of medical therapy and reassessment of the need for revascularization.
As systolic left ventricular dysfunction is asymptomatic in 50–65% of cases , especially when only moderate, there is a strong likelihood that the myocardial impairment will only be diagnosed when already severe and irreversible . The prevalence of systolic left ventricular dysfunction – especially that of moderate forms in patients with stable CAD – is poorly known. Most data come from the Euro Heart Survey , in which left ventricular ejection fraction (LVEF) was greater than 50% in 66% of CAD patients, between 40% and 50% in 23% of CAD patients, and less than 40% in 11% of CAD patients. However, these data must be interpreted with care, as LVEF was measured in only two-third of the study population. In addition, the prevalence of symptoms in CAD patients receiving the most modern treatments is poorly documented.
The main objective of the INDYCE ( insuffisance coronaire stable, dysfonction ventriculaire gauche et fréquence cardiaque ) registry was to evaluate systolic left ventricular function prospectively in a large population of patients with stable CAD. Secondary objectives were to examine patient management, symptoms and heart rate (HR) distribution.
Methods
This prospective, cross-sectional, epidemiological survey was conducted in France. As it was an observational study, it entailed no change in standard patient management. In keeping with French law, all data were collected anonymously and the data file was declared to the French computer watchdog body (Commission nationale de l’informatique et des libertés). The patients were given written information on the nature and aims of the study.
Patients
The study population consisted exclusively of ambulatory patients seen at a hospital or private cardiology consultation. Between 15 June and 31 October 2008, each investigator was asked to recruit prospectively a maximum of 10 consecutive patients with stable CAD.
Patients were eligible if they were greater or equal to 18 years of age and had documented CAD (history of coronary revascularization and/or coronary angiography showing ≥ 1 stenosis > 60%), and/or a history of myocardial infarction or an acute coronary syndrome, and/or clinical angina and a positive ischaemia test (with the exception of an conventional exercise test in women).
Stable CAD was defined by the absence of acute coronary events and myocardial revascularization during the 6 months before inclusion.
Data collection
Echocardiography
LVEF was measured using the Simpson biplane method . An illustrated technical file describing the technique precisely was provided to each investigator.
Clinical data
The monthly number of angina attacks was recorded, and dyspnoea was scored using the New York Heart Association (NYHA) classification. Blood pressure and HR were measured after a 5-minute rest in the supine position; HR was measured from the pulse.
Statistical analysis
Continuous variables are expressed as means ± standard deviations and categorical variables as percentages. Proportions were compared between groups using the Khi 2 test. Overall comparisons between LVEF groups were performed using a one-way analysis of variance model for continuous variables and a Khi 2 test or Fisher’s exact test for categorical variables.
Baseline characteristics were tabulated according to three prespecified ejection fraction strata (< 40%, 40–50%, and > 50%), as used in the ECHOES study . As recent data suggest that HR greater or equal to 70 beats per minute (bpm) has a strong prognostic influence on coronary events , HR values were dichotomized at 70 bpm.
Factors correlating with symptomatic status (i.e. angina attacks and/or NYHA class > I) were identified using univariate and multivariable logistic regression models. Factors that were significant ( α ≤ 0.05) in the univariate analysis were included in the multivariable model, using a stepwise procedure with an entry threshold of 0.10 and an exit threshold of 0.05.
Results
Between June and November 2008, 3193 patients with stable CAD were enrolled consecutively. Seventy-four patients (2.3%) were excluded, because of missing data ( n = 5), non-distribution of written information ( n = 4) or non-respect of inclusion criteria ( n = 65). This analysis focuses on the remaining 3119 patients.
Recruiting centres
Among 979 cardiologists selected by the National Collegiate of French Cardiologists, 554 agreed to participate in the study and 343 actually participated. The demographic characteristics of the cardiologists were similar to those of the 6121 cardiologists practising in France in 2007, based on data from Direction de la récherche des études et de l’évaluation statistique and Observatoire national de la démographie des professions de santé .
Patients
Table 1 shows the patients’ general characteristics. Most of the patients were men (80.3%). The mean age was 68 ± 11 years. Risk factors and comorbidities occurred frequently: nearly one-quarter of the patients were diabetic, 61.6% were hypertensive, 18.6% were active smokers; two-third were overweight and 28.5% also had extracoronary arterial disease.
| Total population ( n = 3119) | LVEF > 50% ( n = 2202) | LVEF 40–50% ( n = 619) | LVEF < 40% ( n = 298) | P | |
|---|---|---|---|---|---|
| Age (years) | 68.4 ± 11.0 | 67.8 ± 10.9 | 69.5 ± 11.0 | 70.5 ± 11.7 | < 0.0001 |
| Men | 80.3 | 79.4 | 84.2 | 78.2 | 0.021 |
| Insulin-dependent diabetes | 5.6 | 4.5 | 6.5 | 11.5 | < 0.0001 |
| Non-insulin-dependent diabetes | 18.7 | 17.7 | 22.3 | 18.6 | 0.037 |
| Hyperlipidaemia | 81.8 | 81.5 | 83.7 | 80.4 | 0.369 |
| High blood pressure | 61.6 | 63.4 | 59.4 | 53.4 | 0.002 |
| Familial coronary artery disease | 25.0 | 25.4 | 23.6 | 24.8 | 0.671 |
| Current smoking | 18.6 | 18.6 | 18.1 | 19.5 | 0.882 |
| Peripheral vascular disease | 28.5 | 26.4 | 31.7 | 37.5 | < 0.0001 |
| Sedentariness | 57.4 | 54.3 | 62.7 | 68.8 | < 0.0001 |
| Asthma | 3.9 | 3.9 | 3.2 | 5.6 | 0.229 |
| COPD | 9.5 | 8.4 | 9.5 | 17.6 | < 0.0001 |
| Chronic renal failure | 13.9 | 10.2 | 18.0 | 33.3 | < 0.0001 |
| Depression | 21.4 | 20.2 | 21.2 | 30.1 | < 0.001 |
| Body mass index | 26.9 ± 4.0 | 26.9 ± 3.9 | 27.1 ± 3.9 | 26.4 ± 4.4 | 0.037 |
| Duration of coronary artery disease (years) | 7.6 ± 6.5 | 6.9 ± 5.9 | 8.7 ± 7.2 | 10.4 ± 8.1 | < 0.0001 |
| Prior myocardial infarction | 44.5 | 35.4 | 63.7 | 72.2 | < 0.0001 |
| Resting heart rate | 64.5 ± 10.4 | 64.0 ± 10.1 | 65.3 ± 10.7 | 66.2 ± 11.5 | < 0.001 |
| Heart rate ≥ 70 beats per minute | 30.1 | 27.9 | 33.5 | 38.6 | < 0.001 |
| Systolic blood pressure (mmHg) | 131.8 ± 15.4 | 132.9 ± 14.9 | 130.7 ± 15.5 | 125.4 ± 16.3 | < 0.0001 |
| Diastolic blood pressure (mmHg) | 75.8 ± 8.4 | 76.2 ± 8.2 | 75.1 ± 8.4 | 73.9 ± 9.1 | < 0.0001 |
| Sinus rhythm | 90.1 | 92.3 | 86.6 | 80.8 | < 0.0001 |
| LVEF (%) | 56.1 ± 11.8 | 62.2 ± 6.9 | 45.9 ± 3.4 | 32.3 ± 5.9 | < 0.0001 |
| Left atrium area (cm 2 ) | 20.4 ± 6.0 | 19.6 ± 5.4 | 21.8 ± 6.9 | 23.8 ± 6.7 | < 0.0001 |
| NYHA class | < 0.001 | ||||
| 0 or I | 43.6 | 50.8 | 31.9 | 14.8 | |
| II | 46.9 | 44.0 | 54.0 | 53.4 | |
| III or IV | 9.6 | 5.3 | 14.2 | 31.9 | |
| Angina (≥ 1 crisis/month) | 19.2 | 16.7 | 23.6 | 29.7 | < 0.001 |
| Asymptomatic patients (NYHA class 0 or I and no angina) | 40.6 | 47.3 | 29.4 | 14.1 | < 0.001 |
| Prior hospitalization for heart failure | 15.2 | 6.7 | 24.8 | 58.7 | < 0.0001 |
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