Summary
Background
The accuracy and reproducibility of stress echocardiography (SE) for the detection of coronary artery lesions requires improvement, particularly in the left circumflex artery (LCx).
Aims
To evaluate the feasibility and diagnostic value of a new sign: Rise of the Apical lateral wall and/or Horizontal displacement of the Apex toward the septum (“RA-HA”) in apical echocardiographic views.
Methods
Consecutive patients with normal left ventricular function at rest, positive SE and an indication for coronary angiography were included. SEs were analysed blindly by three independent cardiologists: two seniors (S1 and S2) and one junior (J).
Results
Of 81 patients, 58 had an exercise SE and 23 had a dobutamine SE. Significant coronary stenosis was found in 59 of 77 patients who underwent coronary angiography (76.6%). Interobserver reproducibility for the presence of RA-HA was very good between S1 and S2 (κ = 0.86), and good between S1 and J (0.67) and S2 and J (0.70). The sensitivity, specificity and positive and negative predictive values of RA-HA for the detection of significant coronary artery stenosis were, respectively, 39–41%, 83–89%, 88–92% and 29–31% for S1/S2; and 29%, 83%, 85% and 26% for J. To predict LCx stenosis (single or multivessel): 67–70%, 89%, 80–81% and 80–82% for S1/S2, respectively, and 50%, 89%, 75% and 74% for J.
Conclusion
With a short learning curve, RA-HA is easily diagnosed with a very good interobserver reproducibility. It has high specificity and PPV for the detection of a coronary artery stenosis, particularly in the LCx artery, during exercise or dobutamine SE.
Résumé
Objectif
La performance diagnostique et la reproductibilité de l’échographie de stress (ES) pour détecter une lésion coronaire est imparfaite, notamment pour l’artère circonflexe. Nous avons évalué la faisabilité et la valeur diagnostique d’un nouveau signe échographique appelé « Aplha » pour ascension de la paroi latérale et/ou déplacement horizontal de l’apex vers le septum dans les incidences apicales.
Méthodes
Quatre-vingt-un patients consécutifs avec une cinétique segmentaire VG normale au repos, une échographie de stress positive (58 en effort et 23 sous dobutamine) et une indication de coronarographie, ont été inclus. Les ES ont été relues en aveugle par trois lecteurs : deux cardiologues seniors (S1 et S2) et un junior (J). « Aplha » était défini comme une ascension du segment apico-latéral et/ou un déplacement horizontal de la pointe vers la droite en incidence apicale 3 ou 4 cavités au pic du stress. Une sténose coronaire significative a été observée chez 59 patients (81 %). La reproductibilité interobservateur pour « Aplha » était très bonne entre S1 et S2 (kappa = 0,86), et bonne entre S1 et J (kappa = 0,67) et S2 et J (kappa = 0,7). Pour la détection d’une lésion coronaire significative, les sensibilité (Se), spécificité (Sp), valeur prédictive positive (VPP) et négative (VPN) de « Aplha » étaient respectivement de 41 %, 89 %, 92 %, et 31 % pour les seniors et 29 %, 83 %, 85 % et 26 % pour J. La performance diagnostique de « Aplha » a été également évaluée pour détecter une sténose circonflexe significative (atteinte mono ou pluritronculaire). Pour S1 et S2 (pas de différence significative), Se = 70 %, Sp = 89 %, VPP = 81 %, VPN = 82 % ; pour J : Se = 50 %, Sp = 89 %, VPP = 75 %, VPN = 74 %.
Conclusion
Après un court apprentissage, « Aplha » est facilement identifié avec une très bonne reproductibilité interobservateur. Il a une très bonne spécificité et VPP pour la détection d’une sténose coronaire, particulièrement la circonflexe, que ce soit pendant l’effort ou sous dobutamine.
Background
Stress echocardiography (SE) has become a reference method for the diagnostic and prognostic evaluation of coronary artery disease . It has good accuracy for the detection of coronary artery stenosis (sensitivity 70–97%; specificity 64–93%), which is similar for exercise and dobutamine echocardiography , but varies according to the artery involved. The reported sensitivity for the identification of left anterior descending (LAD) or right coronary artery (RCA) stenosis is superior to that for left circumflex (LCx) artery stenosis (72% for LAD, 76% for RCA vs 55% for LCx in a meta-analysis ).
The reported reproducibility of interpretation is poor even in expert centres of SE . This can be explained by the fact that diagnosis of ischaemia is based upon subjective criteria such as hypokinesia or a delayed motion of the myocardial wall. To overcome these limitations, quantitative techniques such as tissue Doppler imaging (TDI) or strain using two-dimensional speckle have been proposed . Nevertheless, these are time consuming and not fully validated for clinical practice. In our experience, when the LCx artery is involved, one can often observe an asymmetry of contraction during stress in the four-chamber view, leading to torsion of the apex, which is very easy to recognize. This Rise of the Apical lateral wall and/or Horizontal displacement of the Apex (“RA-HA” sign) can be seen in Fig. 1 . This wallmotion abnormality frequently occurs without a significant hypokinesia or a delayed motion of the endocardium. In the present study, we sought to evaluate the interobserver reproducibility and diagnostic value of this new sign.
Methods
Inclusion criteria
Patients referred to our laboratory for routine diagnostic SE were prospectively considered for inclusion. Consecutive patients were included provided they fulfilled the following criteria: SE considered positive by the cardiologist who performed the test; normal left ventricular function at rest; indication for coronary angiography. Significant valve disease was an exclusion criterion. The decision to perform the angiography was based on routine clinical practice (after discussion with the cardiologist who referred the patient, taking into account clinical symptoms and/or severity of ischaemia). Examinations were reanalysed without any impact on the patient’s treatment.
Stress echocardiography protocols
SE was performed by a senior cardiologist, using a VIVID 7 (General Electric Medical System, Horten, Norway). Basic acquisitions at rest were made to appreciate wall motion contraction. Ejection fraction was evaluated using eyeball estimation and/or using the modified biplane Simpson’s rule.
Exercise echocardiography was performed using a bicycle protocol with the patient in a semisupine position. The patient was asked to pedal at a constant rate of 60–65 rpm, and the workload was increased in a stepwise fashion (increments of 10–40 W every 2 min). Imaging (parasternal long-axis and short-axis, apical long-axis, four-chamber and two-chamber views) was recorded at baseline, at each stage until peak stress, and during recovery (immediately after the end of exercise). A 12-lead electrocardiogram (ECG) was continuously displayed on a screen to provide the operator with a reference for ST-segment changes and arrhythmias. Cuff blood pressure was measured in a resting condition and at each stage thereafter.
The dobutamine stress protocol consisted of a continuous intravenous infusion of dobutamine, starting with 5 mg/kg/min and increasing every 2 minutes to 10, 20, 30 and 40 mg/kg/min. If there were no contraindications, atropine was injected during the 20-mg/kg/min stage of dobutamine (0.25 mg up to a maximum of 1.5 mg). After peak stress images, a beta-blocker (atenolol) was administrated intravenously.
Diagnostic endpoints were: achievement of target heart rate (defined as 85% of the age-predicted maximum heart rate), new or worsening wall-motion abnormalities of moderate degree, maximal dose for dobutamine stress, significant arrhythmias, hypotension (> 40 mmHg drop in blood pressure), severe hypertension (systolic blood pressure > 220 mmHg or diastolic blood pressure > 120 mmHg, and intolerable symptoms (severe chest pain, dyspnea or exhaustion).
Stress echocardiography analysis
The examinations were analysed blindly by three independent readers: two seniors (E.A. and C.C.) and one junior (L.R.), based on a 16-segment model of the myocardium. ECG and clinical status were unknown. Analysis was performed using a quad-screen format (baseline, low stress, peak stress and recovery) for each of the five views. The two seniors readers had to answer the following questions:
- •
what was the informative stage during which the diagnosis made: peak stress or recovery?
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how many segments were considered as ischaemic?
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was there any wall-motion abnormality, namely akinesia, hypokinesia and/or induced delayed contraction (in at least two segments)?
The new sign was a Rise of the Apical lateral wall and/or a Horizontal displacement (pulling) of the Apex towards the septum (RA-HA), in a four-chamber view or in an apical long-axis view, at peak stress or during recovery ( Video S1 ). To evaluate the feasibility of this new sign, we trained a junior cardiologist. This training was very simple and took less than 30 minutes, explaining the RA-HA sign with five video clips of stress echo with typical involvement. The three readers (two seniors and one junior) were then asked to decide whether there was a RA-HA sign.
For each examination, the quality was noted, as well as the systolic blood pressure at peak level, and the percentage of the age-predicted maximum heart rate achieved.
Coronary angiography
All patients underwent coronary angiography within 1 week of SE. Significant coronary artery stenosis was defined as greater or equal to 50% luminal diameter narrowing (visual assessment). Lesions were classified as follow: LAD, LCx, RCA, two-vessel disease (LAD-LCx, LAD-RCA or RCA-LCx) or three-vessel disease.
Statistical analysis
The Cohen κ coefficient for interobserver concordance and for agreement between echographic and angiographic territories was calculated to test the hypothesis that concordance was greater than chance alone. The coefficient of agreement, κ, was graded as poor (0–0.20), fair (0.21–0.40), moderate (0.41–0.60), good (0.61–0.80) or very good (0.81–1.00). The diagnostic value of the RA-HA sign to detect coronary stenosis and to localize the lesion at coronary angiography was also calculated in terms of sensitivity, specificity and positive and negative predictive values (PPV and NPV). Accuracy was calculated as the total number of true positive and true negative tests divided by the total number of patients. A true positive test was defined when a RA-HA sign was present along with a significant lesion on coronary angiography.
Results
Characteristics of the 81 patients are shown in Table 1 , along with information on the type and quality of SE, percentage of age-predicted heart rate achieved and systolic blood pressure.
| All patients ( n = 81) | |
|---|---|
| Men | 52 (64.2) |
| Age (years) | 65 ± 10 |
| Type of SE | |
| Exercise | 58 (71.6) |
| Dobutamine | 23 (28.4) |
| SE image quality | |
| Good | 35 (43.2) |
| Medium | 42 (51.9) |
| Poor | 4 (4.9) |
| ECG at rest | |
| Normal | 76 (93.8) |
| Left bundle branch block | 3 (3.7) |
| Atrial fibrillation | 2 (2.5) |
| Percentage of maximum age-predicted heart rate | 89 ± 12 |
| Systolic blood pressure, mmHg | 197 ± 35 |
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