B-type natriuretic peptide over N-terminal pro-brain natriuretic peptide to predict incident atrial fibrillation after cryptogenic stroke

BACKGROUND AND PURPOSE

B-type natriuretic peptide (BNP) and N-terminal pro-brain natriuretic peptide (NT-proBNP) are well-known surrogates of atrial fibrillation (AF) detection but studies usually present data on either BNP or NT-proBNP. The aim was to determine and directly compare the validity of the two biomarkers as a tool to predict AF and guide prolonged cardiac monitoring in cryptogenic stroke patients.

METHODS

Non-lacunar acute ischaemic stroke (<72 h) patients over 55 years of age with cryptogenic stroke after standard evaluation were included in the Crypto-AF study and blood was collected. BNP and NT-proBNP levels were determined by automated immunoassays. AF was assessed by 28 days' monitoring. Highest (optimizing specificity) and lowest (optimizing sensitivity) quartiles were used as biomarker cut-offs to build predictive models adjusted by sex and age. The integrated discrimination improvement index (IDI) and DeLong test were used to compare the performance of the two biomarkers.

RESULTS

From 320 patients evaluated, 218 were included in the analysis. AF was detected in 50 patients (22.9%). NT-proBNP (P < 0.001) and BNP (P < 0.001) levels were higher in subjects with AF and their levels correlated (r = 0.495, P < 0.001). BNP showed an increased area under the curve (0.720 vs. 0.669; P = 0.0218) and a better predictive capacity (IDI = 3.63%, 95% confidence interval 1.36%-5.91%) compared to NT-proBNP. BNP performed better than NT-proBNP in a specific model (IDI = 3.7%, 95% confidence interval 0.87%-6.5%), whilst both biomarkers performed similarly in the case of a sensitive model.

CONCLUSIONS

Both BNP and NT-proBNP were increased in cryptogenic stroke patients with AF detection. Interestingly, BNP outperforms NT-proBNP, especially in terms of specificity.

Decreased rotational flow and circumferential wall shear stress as early markers of descending aorta dilation in Marfan syndrome: a 4D flow CMR study

BACKGROUND

Diseases of the descending aorta have emerged as a clinical issue in Marfan syndrome following improvements in proximal aorta surgical treatment and the consequent increase in life expectancy. Although a role for hemodynamic alterations in the etiology of descending aorta disease in Marfan patients has been suggested, whether flow characteristics may be useful as early markers remains to be determined.

METHODS

Seventy-five Marfan patients and 48 healthy subjects were prospectively enrolled. In- and through-plane vortexes were computed by 4D flow cardiovascular magnetic resonance (CMR) in the thoracic aorta through the quantification of in-plane rotational flow and systolic flow reversal ratio, respectively. Regional pulse wave velocity and axial and circumferential wall shear stress maps were also computed.

RESULTS

In-plane rotational flow and circumferential wall shear stress were reduced in Marfan patients in the distal ascending aorta and in proximal descending aorta, even in the 20 patients free of aortic dilation. Multivariate analysis showed reduced in-plane rotational flow to be independently related to descending aorta pulse wave velocity. Conversely, systolic flow reversal ratio and axial wall shear stress were altered in unselected Marfan patients but not in the subgroup without dilation. In multivariate regression analysis proximal descending aorta axial (p = 0.014) and circumferential (p = 0.034) wall shear stress were independently related to local diameter.

CONCLUSIONS

Reduced rotational flow is present in the aorta of Marfan patients even in the absence of dilation, is related to aortic stiffness and drives abnormal circumferential wall shear stress. Axial and circumferential wall shear stress are independently related to proximal descending aorta dilation beyond clinical factors. In-plane rotational flow and circumferential wall shear stress may be considered as an early marker of descending aorta dilation in Marfan patients.

Strategy for optimal aortic regurgitation quantification by Doppler echocardiography: agreement among different methods

BACKGROUND

Although different Doppler methods have been validated for aortic regurgitation quantification, the benefit of combining information from different methods has not been defined.

METHODS

Our study included 2 phases. In the initial phase (60 patients), Doppler parameters (jet width, short-axis jet area, apical jet area, regurgitant fraction from pulmonary and mitral flow, and deceleration slope) were correlated with angiography; range values for each severity grade were defined and intraobserver and interobserver and intermachine variability were studied. In the validation phase (158 patients), defined value ranges were prospectively tested and a strategy based on considering as the definitive severity grade that in which the two best methods agreed was tested.

RESULTS

Jet width had the best correlation with angiography (r = 0.91), and its ratio with the left ventricular outflow diameter did not improve the correlation (r = 0.85) and decreased reproducibility. Apical jet area and regurgitant fraction from pulmonary flow permitted acceptable quantification (r = 0.87 and 0.86, respectively) but with worse reproducibility. The other methods were not assessable in 20% to 30% of studies. Concordance with angiography decreased in jet width when the jet was eccentric (90% vs 77%, P <.01), in apical jet area when mitral valve disease was present (84% vs 65%, P <.02), and in short-axis jet area and regurgitant fraction from pulmonary flow with concomitant aortic stenosis (77% vs 44%, P <.002 and 77% vs 53%, P <.02, respectively). Agreement with angiography was very high (94 [95%] of 99) when severity grade coincided in both jet width and apical jet area. In 59 cases without concordance, regurgitant fraction from pulmonary flow was used as a third method. Overall, this strategy permitted concordance with angiography in 146 patients (92%).

CONCLUSIONS

Jet width is the best predictor in aortic regurgitation quantification by Doppler echocardiography. However, better results were obtained when a strategy based on concordance between jet width and another Doppler method was established, particularly when the jet was eccentric.

[Quantification of left-to-right shunt in atrial septal defect using oximetry, isotopes, and Doppler echocardiography. Is there a method of reference?]

INTRODUCTION

Determination of pulmonary to systemic blood flow ratio (QP/QS) is considered to be important for the management of patients with atrial septal defect. The QP/QS provides information on shunt severity and is usually determined by three methods: oximetry, first-pass radionuclide angiocardiography and Doppler echocardiography. The aim of the present study was to assess the accuracy and concordance level of these three methods in QP/QS quantification in atrial septal defects.

PATIENTS AND METHODS

Sixty-four adult atrial septal defects patients in whom QP/QS was determined by these three methods with a 6 month interval were studied. Nuclear and echocardiographic post-surgical studies were repeated in 36 patients.

RESULTS

QP/QS values determined by the three techniques had a low correlation between them: oximetry (r = 0.52; SEE = 0.74); radionuclide angiocardiography (r = 0.40; SEE = 0.79) and Doppler echocardiography (r = 0.72; SEE = 0.57). Radionuclide angiocardiography underestimated QP/QS > 3 (-0.61 +/- 1.21; p < 0.01). Only in 33% of studies there concordance (differences < 0.5) among the three methods and in 58% between two methods. Right ventricular dilatation and tricuspid regurgitation influenced radionuclide accuracy. Nevertheless, the correlation between this technique and echocardiography was satisfactory when the 36 post-surgical were included (r = 0.75); both techniques agreed in the diagnosis of the two cases with residual post-surgical shunt.

CONCLUSIONS

Inter-method disparity in QP/QS quantification is high and no method can be used as a gold standard; clinical decisions therefore based on QP/QS quantification by one technique alone are ill-advised.

[Prognostic value of pre-discharge exertion echocardiography after acute myocardial infarct]

OBJECTIVE

The aim of the present work was to ascertain the usefulness of exercise echocardiography performed prior to discharge following acute non-complicated myocardial infarction in the prognosis and detection of multi-vessel disease.

PATIENTS AND METHODS

Sixty-five consecutive patients with primary episode of acute non-complicated myocardial infarction, with normal or slightly depressed ventricular function, were studied. Submaximal exercise test including echocardiogram pre- and immediately post-exercise were performed 7 to 10 days after infarction. Mean follow-up was 15 +/- 8 months; 15 patients presented angina, 9 revascularization and 1 died.

RESULTS

Electrocardiographic ischaemia had low sensitivity and negative predictive value regarding complications (44% and 73% respectively); however, its specificity and positive predictive values were high (97% and 92%). In contrast, echocardiography-detected ischaemia showed much better sensitivity and negative predictive values (72% and 83%), with a slight decrease in specificity and positive predictive values (87% and 78%). Both remote ischaemia and the increase in global score > 0.25 during exercise were of high prognostic value (p < 0.001). Remote echocardiographic ischaemia yielded the diagnosis of multi-vessel disease with greater sensitivity than electrocardiographic ischaemia (84% vs 41%).

CONCLUSIONS

Exercise echocardiography is highly useful in the prognostic assessment of patients prior to discharge following acute non-complicated myocardial infarction. The ischaemia detected on sub-maximal exercise and assessed by echocardiography was much more sensitive than that detected by electrocardiography in the prediction of new coronary events and multi-vessel disease.

[Thrombus in the thoracic aorta as cause of peripheral embolism diagnosed using transesophageal echocardiography]

The authors report the cases of two patients, with no risk factors for thromboembolism, in whom a mobile thrombus of the thoracic aorta was diagnosed by transesophageal echocardiography, after an episode of systemic embolism. The outcomes of the two cases were very different. In one patient the thrombus was no longer present after anticoagulant treatment with no recurrent embolic event. The other patient had a new embolic event and the thrombus persisted while having anticoagulant therapy. This patient underwent surgery, and the thrombus was removed. These cases illustrate the value of transesophageal echocardiography in the detection of embolic source.

[Normal values of valvular flow velocities determined by Doppler echocardiography: relations with heart rate and age]

INTRODUCTION AND OBJECTIVES

The velocity-time integral (VTI) and the mean velocity of valvular flow are widely-used variables in Doppler-echocardiography. The aim of the present work was to determine normal VTI and mean velocity values of valvular flow and their relation to age, sex, heart rate and body surface area.

METHODS

One hundred and fifty-six patients (84 men, 72 women; age range: 6-86 y; mean: 37 +/- 20) without cardiovascular disease were studied by Doppler echocardiography. VTI and the mean velocity of left and right ventricular outflow tract, and mitral and tricuspid valvular flow were determined by pulsed-wave Doppler. Aortic and pulmonary valvular flow were assessed by continuous wave Doppler.

RESULTS

Mean value of aortic valvular flow VTI (22 +/- 4 cm) was slightly higher than that of pulmonary valvular flow (20 +/- 4 cm). Mean VTI values of left and right ventricular outflow tract and mitral valvular flow were similar (16 +/- 3, 15 +/- 3 and 15 +/- 3 cm, respectively) with an acceptable correlation (r = 0.76-0.83). VTI of tricuspid valvular flow was clearly lower than the rest (10 +/- 3 cm; p < 0.001). Linear regression analysis showed the VTI to be inversely related to heart rate and age, and mean velocity positively related to heart rate and inversely to age. While VTI remained relatively stable up to the age of 60 and decreased sharply thereafter, mean velocity decreased progressively with age. VTI values were identical for both sexes; however, mean velocity was higher in women up to the age of 60.

CONCLUSIONS

VTI is a Doppler parameter independent of body surface area, inversely related to heart rate, not sex-related and remains stable up to the age of 60. Normal mean velocity values should be defined in relation to heart rate and age. Normal values of these Doppler parameters should be borne in mind for non-invasive assessment of cardiovascular function.

[Normal values of valvular annular areas. Comparison of the results of a necropsy and an echocardiographic series]

INTRODUCTION AND OBJECTIVES

Measurement of valvular annular area is necessary for valvular flow volumen quantification by Doppler echocardiography. The aim of this work was to compare normal valvular annular area values obtained in a necropsic and an echocardiographic series and to ascertain whether a relationship exists between these areas and several anthropometric variables.

METHODS

Necropsic series: valvular annular area was measured in 20 hearts from deceased patients (age range: 9-79 years; mean 52 +/- 18) without cardiovascular disease. Echocardiographic series: Valvular annular area was determined in 156 patients (age range: 6-86 years; mean 37 +/- 20) without cardiovascular disease.

RESULTS

Necropsic series: multiple regression analysis showed valvular annular area values to be related mainly to height (p < 0.001) but also to weight (p < 0.01). Correlations between valvular annular area and body surface were low (r = 0.64-0.75). Aortic annular area index was slightly lower than the pulmonary annular area index and half that of the mitral annular area index (2.2 +/- 0.4, 2.5 +/- 0.5 and 4.4 +/- 0.8 cm2/m2, respectively). Tricuspid annular area index was the largest (6.7 +/- 1.0 cm2/m2). ECHOCARDIOGRAPHIC SERIES: Multiple regression analysis also showed a relationship between valvular annular area and height (p < 0.00001) and weight (p < 0.004). Correlations between valvular annular real values and body surface were poor (r = 0.45-0.71). Mean values of aortic, pulmonary and mitral valvular annular area indices were similar to those obtained in the necropsic series (2.1 +/- 0.2, 2.1 +/- 0.3, 4.1 +/- 0.6 cm2/m2, respectively). However, the tricuspid annular area index was clearly lower (4.5 +/- 0.6 cm2/m2, p < 0.001).

CONCLUSIONS

Valvular annular area is influenced mainly by height, but also by weight. The correlation between these values and body surface is poor. Aortic annular area is similar to the pulmonary annular area and half that of the mitral annulus. Normal values determined by echocardiography and necropsy are similar, although tricuspid annular area by apical view is smaller than that obtained in the necropsic series.

[The usefulness of transesophageal echocardiography in the diagnosis of a free-floating thrombus in the left atrium]

The case of a patient with mitral prosthesis who had arterial embolism is presented. The transoesophageal echocardiogram showed a floating thrombus in the left atrium which had not been detected by transthoracic echocardiography. The usefulness of transesophageal echocardiography in the diagnosis of this pathology is emphasized.