A decade of improvement in the management of New Zealand ST-elevation myocardial infarction (STEMI) patients: results from the New Zealand Acute Coronary Syndrome (ACS) Audit Group national audits of 2002, 2007 and 2012

AIMS

To audit the management of ST-segment elevation myocardial infarction (STEMI) patients admitted to a New Zealand Hospital over three 14-day periods to review their number, characteristics, management and outcome changes over a decade.

METHODS

The acute coronary syndrome (ACS) audits were conducted over 14 days in May of 2002, 2007 and 2012 at New Zealand Hospitals admitting patients with a suspected or definite ACS. Longitudinal analyses of the STEMI subgroup are reported.

RESULTS

From 2002 to 2012, the largest change in management was the proportion of patients undergoing reperfusion by primary PCI from 3% to 15% and 41%; P<0.001, and the rates of second antiplatelet agent use in addition to aspirin from 14% to 62% and 98%; P<0.001. The use of proven secondary prevention medications at discharge also increased during the decade. There were also significant increases in cardiac investigations for patients, especially echocardiograms (35%, 62% and 70%, P<0.001) and invasive coronary angiograms (31%, 58% and 87%, P<0.001). Notably even in 2012, one in four patients presenting with STEMI did not receive any reperfusion therapy.

CONCLUSIONS

Substantial improvements have been seen in the management of STEMI patients in New Zealand over the last decade, in accordance with evidenced-based guideline recommendations. However, there appears to be considerable room to optimise management, particularly with the use of timely reperfusion therapy for more patients.

Imaging the premature brain: ultrasound or MRI?

Neuroimaging of preterm infants has become part of routine clinical care, but the question is often raised on how often cranial ultrasound should be done and whether every high risk preterm infant should at least have one MRI during the neonatal period. An increasing number of centres perform an MRI either at discharge or around term equivalent age, and a few centres have access to a magnet in or adjacent to the neonatal intensive care unit and are doing sequential MRIs. In this review, we try to discuss when best to perform these two neuroimaging techniques and the additional information each technique may provide.

The significance of the ultrasound diagnostics in evaluation of the emboligenic pathogenesis of transient ischemic attacks

The objective of this study was to examine the possibilities of ultrasound diagnostics in the evaluation of emboligenic pathogenesis of transient ischemic attacks (TIAs) and the frequency of specific origins of embolism. A total of 150 adult patients with TIA and 50 control patients, were examined by neurosonologic, echocardiographic and venous ultrasound examination. Emboligenic pathogenesis of TIA was established in 36.6% of patients. Microembolic signals were detected in 22.7% of the whole group, and 61.8% in emboligenic TIA subgroup. Artery-to-artery embolism from ulcerated plaque of the carotid arteries was found in 12.6% of patients, from the aortic arch atheroma in 3.3% and cardioembolism in 12.6% (atrial fibrillation 7.3%, atrial septal aneurysm 2%, mitral valve prolapse 2%, mechanical heart valve 0.7%, left atrium thrombus 0.7%). Paradoxic embolism with the patent foramen ovale was established in 6% of patients, and with the pulmonary right-to-left shunt in 2%. Correlation with controls showed significantly higher frequency of the ulcerated carotid plaque and frequency of microembolic signals in the TIA group (p < 0.05). The patients with potential sources of embolism had a greater risk of developing TIA than those without these sources.

Reader variability in the use of diagnostic terms to describe white matter lesions seen on cranial scans of severely premature infants: the ELGAN study

PURPOSE

To evaluate reader variability of white matter lesions seen on cranial sonographic scans of extreme low gestational age neonates (ELGANs).

METHODS

In 1,452 ELGANs, cranial sonographic scans were obtained in the first and second postnatal weeks, and between the third postnatal week and term. All sets of scans were read independently by two sonologists. We reviewed the use of four diagnostic labels: early periventricular leucomalacia, cystic periventricular leucomalacia, periventricular hemorrhagic infarction (PVHI), and other white matter diagnosis, by 16 sonologists at 14 institutions. We evaluated the association of these labels with location and laterality of hyperechoic and hypoechoic lesions, location of intraventricular hemorrhage, and characteristics of ventricular enlargement.

RESULTS

Experienced sonologists differed substantially in their application of the diagnostic labels. Three readers applied early periventricular leucomalacia to more than one fourth of all the scans they read, whereas eight applied this label to ≤5% of scans. Five applied PVHI to ≥10% of scans, while three applied this label to ≤5% of scans. More than one third of scans labeled cystic periventricular leucomalacia had unilateral hypoechoic lesions. White matter abnormalities in PVHI were more extensive than in periventricular leucomalacia and were more anteriorly located. Hypoechoic lesions on late scans tended to be in the same locations, regardless of the diagnostic label applied.

CONCLUSIONS

Experienced sonologists differ considerably in their tendency to apply diagnostic labels for white matter lesions. This is due to lack of universally agreed-upon definitions. We recommend reducing this variability to improve the validity of large multicenter studies.

Supratentorial abnormalities in the Chiari II malformation, III: The interhemispheric cyst

OBJECTIVE

Our clinical observations noted an interhemispheric "cyst," a protrusion of the posterior superior third ventricle, in fetuses with myelomeningocele (MMC). The study analyzed the frequency of this observation and features that influence its visualization.

METHODS

We searched for cases of fetal MMC sonographically detected between 1999 and 2007. Intracranial findings were retrospectively reviewed with attention to the interhemispheric cistern. Additionally, we reviewed 25 fetuses without a central nervous system anomaly and 10 fetuses with ventriculomegaly but no MMC.

RESULTS

Among 89 fetuses identified, the mean gestational age was 22 weeks 4 days. Thirty-eight (43%) had an interhemispheric cyst. The frequency was similar on sonograms judged to be well visualized compared with studies judged to be suboptimally visualized. The degree of ventriculomegaly, timing of diagnosis, and severity of the Chiari II malformation did not appear to influence the frequency of the finding. Among fetuses without a central nervous system anomaly, no interhemispheric cysts were detected; a cyst was detected in 1 of 10 fetuses with ventriculomegaly. Interhemispheric cysts were more likely to be detected in fetuses with the Chiari II malformation than fetuses with ventriculomegaly but without the Chiari II malformation (P = .04).

CONCLUSIONS

Interhemispheric cysts are a common supratentorial feature of the Chiari II malformation. Their presence appears to be unrelated to other features of the Chiari II malformation. Although interhemispheric cysts are seen in other abnormal fetuses, their striking prevalence in the Chiari II malformation should lead to a thorough examination for MMC.

Fetal cerebral ventricular pointing as a marker of spina bifida: incidence and observational agreement

OBJECTIVE

Occipital cerebral ventricular pointing is a promising intracranial marker for spina bifida. We sought to determine (1) the incidence of pointing in fetuses with and without spina bifida and (2) inter-observer and intraobserver agreement for visualizing pointing.

METHODS

Second-trimester transverse axial images of the lateral cerebral ventricles from an equal number of affected and unaffected fetuses were independently reviewed in a blinded fashion by 2 examiners.

RESULTS

Sixty-two fetuses (31 with isolated spina bifida and 31 without) had sonographic examinations at 19.2+/-1.3 weeks (mean+/-SD). Pointing was present in 77.3% of fetuses with spina bifida and 15% of those without by the first examiner and in 78.3% of fetuses with spina bifida and 10% of those without by the second examiner. Interobserver and intraobserver agreement were substantial (kappa=0.69 and 0.78, respectively).

CONCLUSIONS

Ventricular pointing is a highly agreed-on finding that is substantially associated with but not pathognomonic for fetal spina bifida.

Diffuse basal ganglia or thalamus hyperechogenicity in preterm infants

OBJECTIVE

To determine the incidence and factors associated with diffuse basal ganglia or thalamus hyperechogenicity (BGTH) in preterm infants.

STUDY DESIGN

(1) Review of serial neurosonograms among neonates with gestational age (GA) <34 weeks born at Weiler Hospital during a 21-month period; (2) Color Doppler flow imaging; (3) Case-control study using GA group-matched controls; and (4) Blind reading of CT scans or MRIs in patients with BGTH.

RESULTS

Among 289 infants, 24 (8.3%) had diffuse BGTH. Color Doppler flow imaging was normal in nine patients. The incidence of diffuse BGTH was inversely related to GA (P<0.01). Logistic regression (n=96) showed that diffuse BGTH was significantly associated with requirement of high-frequency oscillation (HFO) (P=0.031), severe intraventricular hemorrhage (IVH) (P=0.004), hypotension requiring vasopressors (P=0.040), hypoglycemia (P=0.031) and male gender (P=0.014). Most patients with diffuse BGTH had normal basal ganglia and thalamus on CT/MRI, one had a hemorrhage, and one had an ischemic infarction.

CONCLUSIONS

In our series, diffuse BGTH occurred in 8.3%, and was associated with factors similar to those previously reported. In contrast, several series have reported almost exclusively linear or punctuate hyperechoic foci, corresponding to hyperechogenicity of the lenticulostriate vessels. Our data provide further evidence to suggest that diffuse BGTH and hyperechogenicity of the lenticulostriate vessels are two different entities. Additional studies are required to determine the long-term significance of diffuse BGTH.

Gender comparisons of diagnostic evaluation for ischemic stroke patients

BACKGROUND

Sixty-two percent of all stroke deaths in the United States occur in women. We compared diagnostic evaluations by gender in ischemic stroke patients in a biethnic, population-based study.

METHODS

A random sample of patients with ischemic stroke identified between 2000 and 2002 by BASIC (Brain Attack Surveillance in Corpus Christi Project) were selected for this study (n = 381). Gender differences in the use of stroke diagnostic tests were assessed. Separate multivariable logistic regression models predicting diagnostic test use were constructed, adjusted for age, ethnicity, hypertension, atrial fibrillation, diabetes, history of stroke, coronary artery disease, having a primary care provider, discharge disposition, modified Rankin Scale score at discharge, and insurance status.

RESULTS

The study population consisted of 161 men and 220 women. Median age was 74.3 years. The respective proportions of males and females receiving any carotid artery evaluation were 71% and 62%; brain MRI, 43% and 41%; echocardiography, 57% and 48%; and EKG, 90% and 86%. Multivariable logistic models found that women were less likely to undergo echocardiography (odds ratio [OR] 0.64, CI: 0.42 to 0.98) and carotid evaluation (OR 0.57, CI: 0.36 to 0.91). There was no association of ischemic stroke subtype and gender to explain these results (p = 0.76).

CONCLUSIONS

Despite controlling for explanatory variables, women with stroke were less likely to receive standard diagnostic tests vs men. Intervention is needed to increase access to quality stroke care for women.

Wave equations, dispersion relations, and van Hove singularities for applications of doublet mechanics to ultrasound propagation in bio- and nanomaterials

A fundamental mathematical framework for applications of Doublet Mechanics to ultrasound propagation in a discrete material is introduced. A multiscale wave equation, dispersion relation for longitudinal waves, and shear waves are derived. The van Hove singularities and corresponding highest frequency limits for the Mth-order wave equations of longitudinal and shear waves are determined for a widely used microbundle structure. Doublet Mechanics is applied to soft tissue and low-density polyethylene. The experimental dispersion data for soft tissue and low-density polyethylene are compared with results predicted by Doublet Mechanics and an attenuation model based on a Kramers-Kronig relation in classical continuum mechanics.

Compensatory fuzzy neural networks-based intelligent detection of abnormal neonatal cerebral Doppler ultrasound waveforms

Compensatory fuzzy neural networks (CFNN) without normalization, which can be trained with a backpropagation learning algorithm, is proposed as a pattern recognition technique for intelligent detection of Doppler ultrasound waveforms of abnormal neonatal cerebral hemodynamics. Doppler ultrasound signals were recorded from the anterior cerebral arteries of 40 normal full-term babies and 14 mature babies with intracranial pathology. The features of normal and abnormal groups as inputs to pattern recognition algorithms were extracted from the maximum velocity waveforms by using principal component analysis. The proposed technique is compared with the CFNN with normalization and other pattern recognition techniques applied to Doppler ultrasound signals from various arteries. The results show that the proposed method is superior to the others, and can be a powerful technique to be used in analyzing Doppler ultrasound signals from various arteries.

Comparison of findings on cranial ultrasound and magnetic resonance imaging in preterm infants

OBJECTIVE

To compare findings on hard copies of cranial ultrasound (US) and magnetic resonance imaging (MRI) obtained between birth and term in a group of preterm infants.

PARTICIPANTS AND METHODS

Infants born at or below a gestational age of 30 weeks who underwent cranial US scan and MRI on the same day were eligible for this study. Infants underwent, whenever possible, 3 scans between birth and term. We calculated the predictive probability (PP) of US findings as a predictor of findings on MRI.

RESULTS

Sixty-two paired MRI and US studies were performed between birth and term in 32 infants born at a median gestational age of 27 (range: 23-30) weeks and a median birth weight of 918 (530-1710) grams. US predicted some MRI findings accurately: germinal layer hemorrhage (GLH) on US had a PP of 0.8 with a 95% confidence interval of (0.70-0.90) for the presence of GLH on MRI, intraventricular hemorrhage (IVH) on US had a PP of 0.85 (0.76-0.94) for the presence of IVH on MRI, and severe white matter (WM) echogenicity on US had a PP of 0.96 (0.92-1.0) for the presence of WM hemorrhagic parenchymal infarction on MRI. Other MRI changes were less well-predicted: mild or no WM echogenicity on US had a PP of 0.54 (0.41-0.66) for the presence of normal WM signal intensity on MRI, and moderate or severe WM echogenicity on US had a PP of 0.54 (0.42-0.66) for the presence of small petechial WM hemorrhage and/or diffuse excessive high-signal intensity (DEHSI) in the WM on T2-weighted images on MRI. However, mild/moderate or severe WM echogenicity on US scans performed at >/=7 days after birth had a PP of 0.72 (0.58-0.87) for the presence of WM hemorrhage and/or DEHSI on MRI. There were no cases of cystic periventricular leukomalacia.

CONCLUSION

US accurately predicted the presence of GLH, IVH, and hemorrhagic parenchymal infarction on MRI. However, its ability to predict the presence of DEHSI and small petechial hemorrhages in the WM on T2 weighted images is not as good, but improves on scans performed at >/=7 days after birth. In addition, normal WM echogenicity on US is not a good predictor of normal WM signal intensity on MRI.

Limitations for three-dimensional ultrasound imaging through a bore-hole trepanation

The intraoperative shift of neuroanatomical landmarks that serve as reference points is an unsolved problem in current neuronavigation. Monitoring the position of these landmarks requires repeated intraoperative imaging. We analyzed the effectiveness of a 3-D ultrasound system for imaging through a bore-hole trepanation. A tissue-mimicking ultrasound phantom and plastic pads with bore-holes were utilized for in vitro tests of the system. Reducing the diameter of the simulated bore-hole decreased the image quality and reduced the field of view. The multiple plane mode of the 3-D ultrasound system allows reconstruction of images in arbitrary imaging planes on the basis of intraoperatively acquired 3-D datasets. Selecting planes that are coplanar with preoperative MRI scans, we were able to identify neuroanatomical landmarks in the reconstructed ultrasound images. Repeated 3-D ultrasound during a procedure might, therefore, allow recognition of a shift of these landmarks.

Ultrasound-induced temperature increase in the guinea-pig fetal brain in vitro

The temperature of the brain of fetal guinea pigs was measured in vitro during exposure to an unscanned beam of pulsed ultrasound at intensity ISPTA 2.8 W/cm2. A mean temperature increase of 5.1 degrees C recorded after 2 min of insonation confirms results of an earlier similar study. The water-bath exposure system provided enhanced cooling of superficial tissue by acoustic streaming. When the scalp was removed, the ultrasound-induced temperature increase was substantially reduced (by 35%) due to cooling through radiation force-induced bulk fluid streaming along the direction of propagation in the water bath. The measured temperature increase in guinea pig fetal brain correlated with a modified cranial thermal index.

[The importance of using the cerebral function monitor (CFM) in the neurological prognosis of neonates in intensive care]

Cerebral function monitor (CFM), unlike traditional EEG, allows a long-term evaluation of electric brain activity, without interfering with the nursing of the newborn in the intensive care unit. Our aim was to evaluate the prognostic value of CFM for neurological outcome. We studied 102 newborns (gestational age 34.5 +/- 4.36 weeks; weight 1980 +/- 720 grams) by Multitrace CFM (Lectromed) 5 hours daily in the first week following admission. The patients also underwent cerebral echography, EEG and neurological follow-up to the 24th month. CFM was found to correlate well with the EEG recorded 3 months later. The persistence for at least one week of an I.C. tracing or the normalization of initial tracing have a good prognostic value (positive predictive value 95.23%), a persistently pathologic registration has a negative prognostic value (negative predictive value 85.18%), that even increases if cerebral echographic alterations are demonstrated (98.57%). The association of CFM and ultrasound abnormalities determines a relative risk for neurological motor impairment of 69.14, whereas CFM alone gives a relative risk of 6.4.

[Echographic measurements in the posterior cranial fossa: the normal values of the term and premature newborn infant]

INTRODUCTION

We support the normal standards for two sonographic (US) signs of the posterior cranial fossa, namely the magnitude of the cisterna magna and the height of the fourth ventricle fastigium, in preterm and fullterm infants.

MATERIALS AND METHODS

The cisterna magna was measured as the distance between the inferior aspect of the cerebella vermis and the inner aspect of the occiput. The height of the fourth ventricle fastigium was calculated as the line drawn from the fastigium to the inner aspect of the occiput, close to the opisthion.

RESULTS

The cisterna magna was .46 +/- .13 cm in preterm infants and .45 +/- .1 cm in fullterm infants (the difference was not significant), whereas the height of the fourth ventricle fastigium was 1.7 +/- .26 cm in preterm and 1.9 +/- .16 cm in fullterm infants (the difference was significant, p < .005).

CONCLUSIONS

The finding of a cisterna magna of equal size in preterm and fullterm infants is in agreement with the concept that subarachnoid and cisternal spaces of the posterior fossa are still large at birth and start to decrease in size later in life. Our results suggest that a cisterna magna smaller than .2 cm in height and/or a fastigium closer than 1.2 cm to the basiocciput in preterm and closer than 1.6 cm in fullterm infants indicate, in a proper clinical context, an abnormally low cerebellum position (Arnold-Chiari malformation). On the other hand, cisterna magna values exceeding .72 in preterm and .65 cm in fullterm infants, as well as fastigium values exceeding 2.22 cm in both groups may suggest the presence of the Dandy-Walker complex or of an arachnoid cyst.

Applications of time-series analysis: a case study on the impact of computer tomography

Time-series techniques are applied to an analysis of the use of neurodiagnostic procedures in Athens, to evaluate the effect of the introduction of computer tomography. Results confirm the usefulness of such techniques, but illustrate the dependence of their successful application on the nature and quality of data.

Neurodiagnostic tests in children with brain tumors: changing patterns of use and impact on cost

The utilization of neurodiagnostic tests in the initial work-up in children with brain tumors was relatively stable during the three years before computed tomography (CT) became available. After this test became available there was a significant (P less than .05) reduction in the utilization of cerebral angiography, echoencephalography, electroencephalography, and ventriculography in children with tumors below the tentorium. In children with tumors above the tentorium, only a reduction in the use of cerebral angiography and radioisotopic scanning was demonstrated. These changes have resulted in a significant (P less than .05) reduction in cost to the patient (or third party) for the initial neurodiagnostic work-up. Since CT became available, children with brain tumors undergo fewer tests, and the greatest reduction has been in tests that have the greatest cost.

The impact of computed tomography on neuroradiologic practice

To assess the impact of computed tomography (CT) of the head on neuroradiologic and diagnostic practice, we analyzed its capabilities, performance, and usage in our practice during the past 18 months. The results were compared to similar data on other neurodiagnostic tests, i.e., electroencephalography (EEG), A-mode echoencephalography, cerebral angiography, cerebral pneumography, and nuclide brain scanning. All diagnostic techniques except EEG were used less often as the capabilities of CT became known to our clinicians.

Amplitude-averaged A-scan echoencephalography of a mental hospital population

Two surveys of the population of the local mental hospital were carried out by the Amplitude-Averaging technique for A-scan echoencephalography. A total of twelve cases appeared to have shifted cerebral midline structures. Of these, ten were investigated further and four were thought to be cases of false positive error in patients with marked enlargement of the ventricular system from various causes.

The remaining six cases were thought to be correctly diagnosed by echoencephalography though this was proven in only three patients. Of the six patients believed to have displaced midlines, most if not all were due to unilateral atrophic disease rather than to space-occupying lesions.

The technique would not seem to be economically valuable for the investigation of resident mental hospital patients.