Delayed release of brain natriuretic peptide to identify myocardial ischaemia.

BACKGROUND: A recent pilot study suggested that exercise-induced myocardial ischaemia may lead to a delayed release of cardiac biomarkers, so that later sampling, for example, at 4 h after exercise could be used for diagnostic purpose. MATERIALS AND METHODS: In an observational study, we enrolled 129 consecutive patients referred for evaluation of a suspected coronary artery disease by rest/stress myocardial perfusion single-photon emission computed tomography. The treating cardiologist used all available clinical information to quantify clinical judgment regarding the presence of myocardial ischaemia using a visual analogue scale twice: prior and after stress testing. BNP levels were determined in a blinded fashion at rest, at peak stress and 4 h after peak stress. The presence of myocardial ischaemia was adjudicated based on perfusion single-photon emission computed tomography and coronary angiography findings by an independent cardiologist. RESULTS: Myocardial ischaemia was detected in 58 patients (45%). Patients with myocardial ischaemia had significantly higher BNP levels at all times, compared to patients without ischaemia: BNP rest (99 vs. 61 pg/mL P = 0·007), BNP stress (125 vs. 77 pg/mL P = 0·02) and BNP 4 h (114 vs. 71 pg/mL P = 0·018). Diagnostic accuracy as quantified by the area under the receiver operating characteristics curve (AUC) was moderate for all time points (AUC 0·64-0·66). The change in BNP between rest and 4 h did not provide added value, neither to the baseline BNP level nor to clinical judgment. CONCLUSION: In contrast to our hypothesis, myocardial ischaemia did not lead to a differential delayed release of BNP. Late sampling did not seem clinically useful.

Incremental value of a single high-sensitivity cardiac troponin I measurement to rule out myocardial ischemia.

BACKGROUND: The aim of this study was to investigate the value of a novel high-sensitivity cardiac troponin I measurement to rule out exercise-induced myocardial ischemia in patients without known coronary artery disease. METHODS: We included 714 patients without previously known coronary artery disease who were referred for rest/stress myocardial perfusion single photon emission tomography. All clinical information available to the treating cardiologist was used to quantify the clinical judgment regarding the presence of exercise-induced myocardial ischemia using a visual analogue scale twice: once before and once after bicycle exercise stress testing. High-sensitivity cardiac troponin I measurements were obtained before stress testing in a blinded manner. The presence of exercise-induced myocardial ischemia was adjudicated on the basis of myocardial perfusion single photon emission tomography combined with coronary angiography findings. RESULTS: Exercise-induced myocardial ischemia was detected in 167 participants (23.4%). High-sensitivity cardiac troponin I levels were significantly higher in patients with exercise-induced myocardial ischemia (4.0 ng/L [95% confidence interval, 2.8-8.6] vs 2.6 ng/L [95% confidence interval, 1.8-4.1], P < .001) and remained an independent predictor of ischemia in multivariable analysis (P < .001). Combining clinical judgment before exercise testing with high-sensitivity cardiac troponin I levels increased diagnostic accuracy as quantified by the area under the receiver operating curve from 0.64 to 0.73 (P < .001), which also tended to be superior to clinical judgment after exercise testing (0.69, P = .056). A single resting high-sensitivity cardiac troponin I measurement provided similar diagnostic accuracy as integrated clinical judgment after exercise testing including work load, as well as symptoms and electrocardiogram changes (0.70 vs 0.69, P = not significant). CONCLUSIONS: High-sensitivity cardiac troponin I measurements seem to complement noninvasive clinical assessment in patients with suspected coronary artery disease.

B-type natriuretic peptide and clinical judgment in the detection of exercise-induced myocardial ischemia.

BACKGROUND: Myocardial ischemia has been shown to be associated with increased levels of B-type natriuretic peptide (BNP). However, it remains unclear whether and how BNP levels could be used clinically in patients with suspected exercise-induced myocardial ischemia. METHODS: We enrolled 274 consecutive patients with suspected exercise-induced myocardial ischemia referred for evaluation by rest/bicycle myocardial perfusion single-photon emission computed tomography (SPECT). All clinical information available to the treating cardiologist was used to quantify the clinical judgment regarding the presence of myocardial ischemia using a visual analogue scale twice: once before and once after bicycle exercise stress testing. BNP measurements were obtained before, immediately after, and 2 hours after stress testing in a blinded manner. The presence of myocardial ischemia was adjudicated on the basis of perfusion SPECT combined with coronary angiography findings. RESULTS: Exercise-induced myocardial ischemia was adjudicated to be present in 103 patients (38%). BNP levels were significantly higher at all time points in patients with myocardial ischemia compared with those without (P < .01 for all). The accuracy of BNP levels as quantified by the area under the receiver operating characteristic curve (AUC) was similar among the time points evaluated (AUC, 0.677-0.697). Combining clinical judgment before exercise testing with BNP levels at rest increased diagnostic accuracy from AUC 0.708 to 0.754 (P = .018). When combining clinical judgment after exercise testing with BNP levels, AUC increased from 0.741 to 0.771 (P = .055). CONCLUSIONS: Combining clinical judgment with BNP levels increased the diagnostic accuracy regarding the presence of myocardial ischemia.

Similar prevalence of expanded CGG repeat lengths in the fragile X mental retardation I gene among infertile women and among women with proven fertility: a prospective study.

PURPOSE: We sought to determine the usefulness of fragile X mental retardation 1 (FMR1) carrier testing among young infertile women with or without signs of ovarian insufficiency as compared with fertile women. METHODS: Three cohorts of women were recruited to determine the cytosine-guanine-guanine (CGG) repeats trinucleotide repeat length in the 5'-untranslated region of the FMR1 gene in lymphocyte DNA. A total of 199 fertile women, who were reported to have conceived within 3 months, were recruited together with 372 infertile women with ongoing menstrual cycles and 48 infertile women with primary ovarian insufficiency. The various ranges of FMR1 CGG repeat lengths among infertile women were compared with those of fertile controls. In infertile women with ongoing menstrual cycles, the serum concentrations of follicle-stimulating hormone, anti-Muellerian hormone, and inhibin B were measured during the early follicular phase. RESULTS: None of the three categories of FMR1 CGG repeat length expansions (premutation, intermediate range, and high normal range) were more prevalent among infertile women than among fertile women. The CGG repeat length was not correlated with any of the ovarian reserve parameters. CONCLUSION: In comparison with a generalized preconception screening strategy, infertility as a criterion, even together with reduced ovarian reserve, is not suitable for identifying a higher proportion of women with expanded FMR1 CGG repeat length.