Emergency department triage of patients with acute chest pain: definition of cardiac troponin I decisional value to manage patients without electrocardiographic evidence of ischemia

The aim of this study was to define the use of a new cardiac troponin I (cTnI) assay for emergency patients with chest pain and no specific electrocardiographic changes consistent with the presence of ischemia. Patients (n=106) admitted in Emergency/Cardiology Departments for chest pain and suspicion of acute coronary syndrome (ACS) were randomized into two diagnosis groups (ACS or non-ACS) by two independent cardiologists. cTnI measurements were performed at admission, and 6 hours and 12 hours later with a new generation assay (Access AccuTnI, Beckman Coulter). Using an upper reference limit of 0.04 μg/l, 27 patients had a cTnI elevation not related to the final diagnosis of ischemia; the positive predictive value (PPV) was 67% with specificity 48%. The decisional value was re-defined and set at 0.16 μg/l, a concentration corresponding to the 99th percentile of the non-ACS patient group. Precision (coefficient of variation) was 8% at this level, PPV 97% and specificity 98%. This new decisional value is now used in our institution and could be included in standard care guidelines to improve the management of patients presenting chest pain in emergency departments.

A critical appraisal of the prognostic value of the VE/VCO2 slope in chronic heart failure

BACKGROUND

Increased ventilatory drive, reflected by the slope of increase of ventilation relative to carbon dioxide production (VE/VCO2 slope), has been shown to have a high prognostic value in patients with chronic heart failure (CHF). However, there is no consensus on how to calculate it, as the relation between VE and VCO2 becomes nonlinear near the end of exercise, when ventilation is driven both by CO2 output and by decrease in plasma pH. This may influence the results.

METHODS

Ninety-seven CHF patients with ejection fraction <45% (mean 27 +/- 9%), in NYHA class II-IV underwent a cardiopulmonary exercise test. VE/VCO2 slope was assessed by linear regression using all the data points (Sl), using only points before (Sli), or after (Slf) the non-linear part of the curve, and using only the first 3-min data (Sl3 min). Peak oxygen uptake (VO2), and circulatory power (VO2 x systolic arterial pressure) were also assessed. Death and transplantation were the end-points considered (mean follow-up 22 months).

RESULTS

Mean value of VE/VCO2 overall slope was 39.3 +/- 11.6 (22-78). In 64% of the patients, two distinct slopes could be found: an initial, linear slope (31.8 +/- 7.5, 18-62) and a final, steeper slope (48.6 +/- 15.7, 24-101). Patients in whom no rupture of slope was observed were sicker. There was a relation between initial and overall VE/VCO2 slopes (r=0.915, P<10(-4)) and between overall and 3-min VE/VCO2 slopes (r=0.808, P<10(-4)). VE/VCO2 slope correlated with peak VO2 (r=-0.55, P<10(-4)) and peak circulatory power (r=-0.49, P<10(-4)). Univariate analysis showed that the prognostic value of overall VE/VCO2 slope (chi2 25.4, P<10(-4)) was greater than initial (chi2 22.8, P<10(-4)), 3-min (chi2 14.6, P<10(-4)) or final VE/VCO2 slopes (chi2 6.7, P=0.09). By multivariate analysis, the prognostic value of the peak circulatory power was similar to that of the VE/VCO2 overall slope.

CONCLUSIONS

The VE/VCO2 slope should be computed from all the data points to have its highest prognostic value. Peak circulatory power also has similar prognostic value.

Recurrent valvular replacement due to exacerbation of Behcet's disease by Streptococcus agalactiae infection

Valvular heart complications in Behcet's disease are rarely reported. Moreover, the risk of dehiscence in postoperative valvular replacement is high in Behcet's disease. We report a case of recurrent aortic prosthetic dehiscence revealing Behcet's disease in a young woman. Each disease exacerbation was concomitant to a Streptococcus agalactiae infection. This infection appears to act as a trigger for Behcet's disease exacerbation. The patient was successfully treated with immunosuppression plus antibiotic therapy.

Comparative value of Doppler echocardiography and B-type natriuretic peptide assay in the etiologic diagnosis of acute dyspnea

OBJECTIVES

We compared the accuracy of B-type natriuretic peptide (BNP) assay with Doppler echocardiography for the diagnosis of decompensated congestive left-heart failure (CHF) in patients with acute dyspnea.

BACKGROUND

Both BNP and Doppler echocardiography have been described as relevant diagnostic tests for heart failure.

METHODS

One hundred sixty-three consecutive patients with severe dyspnea underwent BNP assay and Doppler echocardiogram on admission. The accuracy of the two methods for etiologic diagnosis was compared on the basis of the final diagnoses established by physicians who were blinded to the BNP and Doppler findings.

RESULTS

The final etiologic diagnosis was CHF in 115 patients. Twenty-four patients (15%) were misdiagnosed at admission. The BNP concentration was 1,022 +/- 742 pg/ml in the CHF subgroup and 187 +/- 158 pg/ml in the other patients (p < 0.01). A BNP cutoff of 300 pg/ml correctly classified 88% of the patients (odds ratio [OR] 85 [19 to 376], p < 0.0001), but a high negative predictive value (90%) was only obtained when the cutoff was lowered to 80 pg/ml. The etiologic value of BNP was low in patients with values between 80 and 300 pg/ml (OR 1.85 [0.4 to 7.8], p = 0.4) and also in patients who were studied very soon after onset of acute dyspnea. Among the 138 patients with assessable Doppler findings, a "restrictive" mitral inflow pattern had a diagnostic accuracy for CHF of 91% (OR 482 [77 to 3,011], p < 0.0001), regardless of the BNP level.

CONCLUSIONS

Bedside BNP measurement and Doppler echocardiography are both useful for establishing the cause of acute dyspnea. However, Doppler analysis of the mitral inflow pattern was more accurate, particularly in patients with intermediate BNP levels or "flash" pulmonary edema.

Combined dipyridamole-exercise stress echocardiography for detection of myocardial ischemia in hemodialysis patients: an alternative to stress nuclear imaging

BACKGROUND

Stress nuclear imaging is the noninvasive technique currently used to detect coronary artery disease (CAD) in dialysis patients. Stress echocardiography is recognized as an alternative to stress nuclear imaging for the general population. The aim of this study is to assess the diagnostic accuracy of stress echocardiography for detecting myocardial ischemia in hemodialysis patients.

METHODS

Stress echocardiography and stress technetium-99m-tetrofosmin (Myoview; Amersham International Plc) imaging were performed simultaneously for 66 asymptomatic hemodialysis patients in a single session, using a combination of high-dose dipyridamole and symptom-limited exercise. Coronary angiography was performed in 44 patients with at least one abnormal noninvasive test result or who were considered high-risk despite normal noninvasive test results.

RESULTS

Results for stress echocardiography were abnormal in 15 patients (22%); stress Myoview, in 14 patients (21%); and coronary angiography, in 12 patients (18%). The sensitivity of stress echocardiography for detecting myocardial ischemia (defined as stress Myoview defect) was 86%; specificity, 94%; positive predictive value, 80%; negative predictive value, 96%; and overall accuracy, 92%. The sensitivity of stress echocardiography for detecting CAD (defined as abnormal coronary angiography result) was 83%; specificity, 84%; positive predictive value, 67%; negative predictive value, 93%; and overall accuracy, 84%. Stress echocardiography and stress Myoview did not differ significantly in overall accuracy for detecting CAD (84% versus 91%; P = not significant).

CONCLUSION

In hemodialysis patients, combined dipyridamole-exercise echocardiography is an accurate method to detect both myocardial ischemia and CAD and represents an alternative to stress nuclear imaging.

A non-invasively determined surrogate of cardiac power ('circulatory power') at peak exercise is a powerful prognostic factor in chronic heart failure

OBJECTIVES

This study was designed to assess the prognostic value of a new variable derived from a cardiopulmonary exercise test, the circulatory power, a surrogate of cardiac power, at peak exercise, in patients with chronic heart failure.

BACKGROUND

Peak exercise cardiac power and stroke work are invasive parameters with recently proven prognostic value. It is unclear whether these variables have better prognostic value than peak oxygen uptake (VO(2)).

METHODS

The study population comprised 175 patients with chronic heart failure (ejection fraction <45%) who underwent a cardiopulmonary exercise test. Circulatory power and circulatory stroke work were defined as the product of systolic arterial pressure and VO(2) and oxygen pulse, respectively. Prognostic value was assessed by survival curves (Kaplan-Meier method) and uni- and multivariate Cox analyses.

RESULTS

With a mean follow-up of 25+/-10 months, ejection fraction, heart rate, systolic arterial pressure, peak VO(2), VCO(2), the anaerobic threshold, minute ventilation, the ventilatory equivalents of oxygen and carbon dioxide, the half times of VO(2) and VCO(2) recoveries, and the circulatory stroke work and power predicted outcome. Multivariate analysis demonstrated that the peak circulatory power (chi-square=19.9, P<0.001) (but not peak circulatory stroke work) was the only variable predictive of prognosis.

CONCLUSION

The prognostic value of cardiopulmonary exercise tests in heart failure patients can be improved by assessing a new variable, the circulatory power - a surrogate of cardiac power - at peak exercise.

[Ultra-rapid measurement of brain natriuretic peptide]

B-type natriuretic peptide (BNP) is secreted by overloaded ventricles. Emerging of bedside dosages cause an increasing interest for this peptide as marker in various clinical situations with heart failure. At first, BNP dosage is a potential tool for detecting heart failure and left ventricular dysfunction. BNP has also a powerful and well-established prognosis value in chronic heart failure. In the emergency setting, and mainly about acute dyspnea, low blood BNP level could eliminate diagnosis of congestive heart failure. Moreover, serial measurement of BNP could allow non-invasive hemodynamic monitoring during decompensated heart failure and could also lead cares as need for intensifying treatment. Nevertheless, its daily use in various clinical situations require that cut-off values are refined.

Myocardial gene therapy

Myocardial gene therapy was born at the beginning of the 90's from the marriage of well-defined pathophysiological mechanisms with recombinant adenovirus technology. Together with the development of relatively simple vector delivery procedures during the last few years, this made it possible to consider the possibility of treating diseases such as ischemic cardiomyopathies by the delivery of angiogenic factors and to bring the first proof, in rats, that myocardial gene therapy for experimental heart failure can improve cardiac performance and prolong life duration of the animals. It is now conceivable that such an approach will be applied to human heart failure within the next years. In contrast, regarding familial cardiomyopathies and channelopathies, because of the specificity of each disease type and complexity of the pathophysiology of each mutation, it is likely that much more time will be necessary. However, a number of barriers still exist before myocardial gene therapy can spread to the field of routine clinical cardiology, including finding a safe vector allowing good transduction efficiency rates to cardiac myocytes when delivered through coronary arteries. In contrast, it is conceivable that in the open chest setting, myocardial gene therapy will rapidly be used by surgeons, by itself or in association with the injection of "wild" cells or cells transfected with various types of genes. It can now be assumed that such biotherapies will soon offer patients suffering from myocardial diseases (and especially heart failure) the perspective of major therapeutic progresses.

[Functional mitral insufficiency: a neglected vascular lesion?]

Functional mitral regurgitation is usually neglected during the course of dilated cardiomyopathies. However, functional mitral regurgitation is a sensitive marker of decreased survival. Recent development of treatments such as new surgical approach, permanent biventricular pacing and beta-blockade therapy lead to assess and treat more specifically the accompanying functional mitral regurgitation in congestive heart failure.

How to optimize in vivo gene transfer to cardiac myocytes: mechanical or pharmacological procedures?

An efficient gene delivery system is a prerequisite for myocardial gene therapy. Among the various procedures studied so far, catheter-based percutaneous gene delivery to the myocardium through the coronary vessels seems the most relevant to routine clinical practice; however, the optimal conditions remain to be determined. We selectively infused adenoviral vectors encoding luciferase (1 x 10(9) PFU) or beta-galactosidase (1 x 10(10) PFU) into coronary arteries of adult rabbits in various experimental conditions. Coronary artery occlusion for 30 sec, during and after adenovirus delivery, was required to observe luciferase activity in the target area of the circumflex artery (4.0 +/- 1.0 x 10(5) vs. 1.1 +/- 0.2 x 10(4) RLU/mg with and without coronary occlusion, respectively, p < 0.01, and 1.0 +/- 0.1 x 10(3) RLU/mg using nonselective infusion). When adenoviruses were delivered using high-pressure infusion (82 +/- 12 vs. 415 +/- 25 mmHg before and during infusion, respectively, p < 0.01), luciferase activity increased to 8.5 +/- 2.5 x 10(5) RLU/mg (p < 0.05 vs coronary occlusion alone). Coronary venous sinus occlusion with saline buffer retroinfusion starting before and during anterograde adenovirus delivery resulted in a further 4.7-fold increase in luciferase activity (4.4 +/- 0.8 x 10(6) RLU/mg, p < 0.01) with 5-25% blue-stained myocytes in the target area, compared with 0-5% with the other procedures. Histamine or VEGF-A(165) pretreatment, used to increase vascular permeability, slightly increased gene transfer efficiency (8.5 +/- 2.0 x 10(5) and 9.0 +/- 2.5 x 10(5) RLU/mg respectively, p < 0.05 vs. coronary occlusion alone). We conclude that catheter-mediated adenoviral gene transfer to cardiac myocytes through coronary vessels can be a very efficient procedure for myocardial gene therapy, particularly when the vector residence time and perfusion pressure in the vessels are increased.

[Papillary fibroelastoma: a rare but treatable cause of cerebral infarction]

INTRODUCTION

Papillary fibroelastoma is a benign cardiac tumor which can be associated with serious embolic complications.

EXEGESIS

We report on a 42-year-old man admitted for an ischemic stroke in the left middle cerebral artery region. Transesophageal echocardiography revealed a mitral valve tumor. Surgical excision and histological examination showed a papillary fibroelastoma. Clinical course was uneventful.

CONCLUSION

We consider the high embolic potential of this tumor, which represents a surgically treatable cause of ischemic stroke.

Adenoviral SERCA1a gene transfer to adult rat ventricular myocytes induces physiological changes in calcium handling

OBJECTIVE

We examined the functional consequences of expressing adult rabbit fast skeletal sarcoplasmic reticulum (SR) Ca(2+)-ATPase (SERCA1a) in isolated adult rat ventricular myocytes.

METHODS

Myocytes were infected with a recombinant adenovirus harboring SERCA1a. Then 2 days after myocyte infection, protein expression was estimated using Western blot and SDS-PAGE analysis. We also measured the ATP-dependent oxalate-facilitated Ca(2+) uptake of myocyte homogenates and monitored Ca(2+) transient in myocytes loaded with the Ca(2+) dye, indo-1.

RESULTS

SERCA1a gene expression resulted in a 36% increase in the total SERCA protein level in infected myocytes compared to controls (P<0.01), while SERCA2 and phospholamban levels did not change. This increase was associated with a 42% rise in SR Ca(2+) uptake (P<0.01), while tau (the time constant of Ca(2+) transient decay), and the time to peak fell by 32% (P<0.01) and 38% (P<0.001), respectively. Increasing the frequency of stimulation from 0.2 to 2 Hz decreased tau in both cell types (P<0.01). However, the decrease was much smaller in infected (P<0.01) than in uninfected cells (P<0.001). Isoproterenol (1 microM) further decreased tau in infected myocytes by 23% (P<0.05). In these cells, the diastolic [Ca(2+)](i) decreased by 50% (P<0.05) while the systolic [Ca(2+)](i) increased by 19% (P<0.05). No difference was found in the speed of SR Ca(2+) reloading after caffeine washout between the two cell types.

CONCLUSION

Adenovirus-mediated SERCA1a gene transfer to adult rat ventricular myocytes enhances SR Ca(2+) handling to a degree similar to that observed following physiological stimulation.

Evidence of cardiac myolysis in severe nonischemic heart failure and the potential role of increased wall strain

BACKGROUND

Myocyte death could play a role in heart failure (HF) irrespective of the presence of coronary artery disease. The study aimed to assess this hypothesis by use of the cardiac troponin I (cTnI) assay.

METHODS AND RESULTS

Seventy-one patients with nonischemic HF, New York Heart Association (NYHA) class II-IV, with a normal coronary angiogram and after exclusion of myocardiopathies were evaluated in the study. The control group included 9 healthy subjects and 15 patients hospitalized for severe noncardiac dyspnea. Cardiac TnI concentrations were determined at admission with a research reagent (cTnIus) characterized by a detection limit of 0.026 ng/mL and a high analytic sensitivity of 0.002 ng/mL. cTnIus levels were more than 0.026 ng/mL in 19 HF patients, ranging between 0.027 and 0.463 ng/mL, whereas no cTnIus level was detectable in the control group. With use of a reference assay, only 2 HF patients had abnormal cTnI values. Severe HF was observed in 17 of these 19 patients, assessed by NYHA class IV or by the presence of pulmonary edema. Patients with an increased cTnIus level had a more restrictive mitral Doppler pattern (P <.001) and a more distinctive left ventricular (LV) concentric remodeling (P <.0001), whereas LV ejection fraction was similar in both HF groups. The increased cTnIus level was also associated with a LV wall strain biologic marker (ie, an increased brain natriuretic peptide plasma level) (P <.001).

CONCLUSIONS

cTnI assay is a promising biochemical method for detecting cardiac myolysis in HF, independent of the presence of coronary artery disease. This subtle myolysis could be in part related to the severely increased LV wall strain.

[Drug prospects in the treatment of heart insufficiency]

Pharmacological and validated treatment of chronic heart failure (HF) includes successively angiotensin converting enzyme inhibitors (ACEi), beta-blockers and antialdosterone, which is associated with diuretics. The effectiveness of this manner in which to block more and more hormonal systems demonstrate the validity of the "hormonal" paradigm to explain heart failure. Therefore broader educational means are required to increase the prescription of these drugs for HF. Several questions about these drugs remain unresolved: HF with preserved systolic function and elderly patients, class effect, and the role of antagonists of angiotensin II receptors (as an alternative or associated with ACEi). Other short- and mid-term pharmacological perspectives target target hormonal systems and cytokines: endothelin-receptor antagonists, inhibition of natriuretic peptide degradation (via neutral endopeptidase), and newer drugs acting against TNF such as etanercept. Moreover, recent knowledge about molecular mechanisms of myocardium remodeling allows new drug strategies with target more specifically remodeling such as metalloproteinases. Finally, these perspectives should be largely modified by on-going research in the field of genomics.

ST-segment elevation in precordial leads: anterior or right ventricular myocardial infarction?

Isolated acute right ventricular (RV) infarction is rare, and ECG diagnosis may be difficult. We report two cases of acute myocardial infarction with ST-segment elevation in anterior precordial leads caused by such an RV involvement. Potential mechanisms for the relationship are given.

Increasing endothelial cell permeability improves the efficiency of myocyte adenoviral vector infection

BACKGROUND

Gene delivery to the myocardium using blood-borne adenoviral vectors is hindered by the endothelium, which represents a barrier limiting the infection rate of underlying myocytes. However, endothelial permeability may be modulated by pharmacological agents.

METHODS

In the present study, we modeled the endothelial barrier in vitro using a human umbilical vein endothelial cell (HUVEC) monolayer seeded on a Transwell membrane as a support and diffusion of fluorescent dextrans as a permeability index. We used alpha-thrombin (100 nM) as a pharmacological agent known to increase endothelial permeability and tested the barrier function of the endothelial cell monolayer on adenovector-mediated luciferase gene transfer to underlying isolated cardiac myocytes.

RESULTS

A confluent HUVEC monolayer represented a considerable physical barrier to dextran diffusion; it reduced the permeability of the micropore membrane alone to fluorescein isothiocyanate (FITC)-labeled dextrans of molecular weights 4, 70, 150 and 2000 kDa by approximately 54, 78, 88 and 98%, respectively. Alpha-thrombin (100 nM) increased the permeability coefficients (P(EC)) by 276, 264, 562 and 4166% for the same dextrans, respectively. A confluent HUVEC monolayer represented a major impediment to adenovector-mediated luciferase gene transfer to cardiac myocytes, largely reducing gene transfer efficiency. However thrombin induced a nine-fold increase in myocyte infection.

CONCLUSION

In our model, the endothelial cell monolayer represents a major impediment to myocyte adenovector-mediated gene transfer which can be partially improved by pharmacologically increasing endothelial permeability. The Transwell model is therefore particularly useful for testing the efficiency of pharmacological agents in modulating adenovector passage through the endothelial barrier.

[Ambulatory management of chronic cardiac failure. Possible value of health networking]

Cardiac failure is one of the commonest medical conditions. It usually affects the elderly and is responsible for repeated hospital admission with its high cost for the social security. Several attempts at ambulatory management in certain countries have been successful. Their application may be possible in France. The setting up of health systems like the ones which exist for diabetes, could be a solution to the problem.

[Diastolic heart failure. Signs and diagnosis]

A WELL-RECOGNIZED ENTITY: Diastolic heart failure is an increasingly common diagnosis. Signs may be misleading and positive etiological diagnosis remains difficult.

CLINICAL SIGNS AND COMPLEMENTARY INVESTIGATIONS

Fatigue, and most importantly dyspnea, are the cardinal signs of diastolic heart failure. Cor pulmonale is often the inaugural sign. The physical examination contributes little to diagnosis. The chest x-ray shows a small heart. Electrocardiographic anomalies are almost always found. A hemodynamic exploration of the right heart, the key diagnostic tool not always performed in routine work-ups, evidences increased filling pressure of the left ventricle. Doppler-echocardiography is used widely. It demonstrates preservation of the left ventricle function (normal ejection fraction) and visualizes the anatomic subtratum of the diastolic dysfunction, quantifying filling and relaxation disorders and allowing an indirect estimation of pulmonary pressures. In the future, it will be possible to assay atrial natriuretic peptide which will provide a most useful tool for the positive diagnosis of this type of heart failure.

CONCLUSION

The diagnosis of diastolic heart failure is complex, warranting rigorous, and critical, evaluation of left ventricular filling using noninvasive methods, particularly Doppler-echocardiography.