Detecting myocardial infarction in critical illness using screening troponin measurements and ECG recordings

Introduction

To use screening cardiac troponin (cTn) measurements and electrocardiograms (ECGs) to determine the incidence of elevated cTn and of myocardial infarction (MI) in patients admitted to the intensive care unit (ICU), and to assess whether these findings influence prognosis. This is a prospective screening study.

Materials and methods

We enrolled consecutive patients admitted to a general medical-surgical ICU over two months. All patients underwent systematic screening with cTn measurements and ECGs on ICU admission, then daily for the first week in ICU, alternate days for up to one month and weekly thereafter until ICU death or discharge, for a maximum of two months. Patients without these investigations ordered during routine clinical care underwent screening for study purposes but these results were unavailable to the ICU team. After the study, all ECGs were interpreted independently in duplicate for ischaemic changes meeting ESC/ACC criteria supporting a diagnosis of MI. Patients were classified as having MI (elevated cTn and ECG evidence supporting diagnosis of MI), elevated cTn only (no ECG evidence supporting diagnosis of MI), or no cTn elevation.

Results

One hundred and three patients were admitted to the ICU on 112 occasions. Overall, 37 patients (35.9 per cent) had an MI, 15 patients (14.6 per cent) had an elevated cTn only and 51 patients (49.5 per cent) had no cTn elevation. Patients with MI had longer duration of mechanical ventilation (p < 0.0001), longer ICU stay (p = 0.001), higher ICU mortality (p < 0.0001) and higher hospital mortality (p < 0.0001) compared with those with no cTn elevation. Patients with elevated cTn had higher hospital mortality (p = 0.001) than patients without cTn elevation. Elevated cTn was associated with increased hospital mortality (odds ratio 27.3, 95 per cent CI 1.7 – 449.4), after adjusting for APACHE II score, MI and advanced life support. The ICU team diagnosed 18 patients (17.5 per cent) as having MI on clinical grounds; four of these patients did not have MI by adjudication. Thus, screening detected an additional 23 MIs not diagnosed in practice, reflecting 62.2 per cent of MIs ultimately diagnosed. Patients with MI diagnosed by the ICU team had similar outcomes to patients with MI detected by screening alone.

Conclusion

Systematic screening detected elevated cTn measurements and MI in more patients than were found in routine practice. Elevated cTn was an independent predictor of hospital mortality. Further research is needed to evaluate whether screening and subsequent treatment of these patients reduces mortality.     

Adherence to Clinical Practice Guideline Recommendations in Women with Gestational Diabetes and Associations with Maternal and Infant Health—A Cohort Study

Gestational diabetes mellitus (GDM) is managed by dietary advice, but limited evidence exists about the impact of adherence on health. We assessed whether adherence to the New Zealand Ministry of Health dietary recommendations is associated with maternal and infant health in women with GDM. Data from 313 women with GDM were used. Adherence to food-related recommendations was scored from 0 (no adherence) to 10 (adhered to all recommendations) and analysed in tertile groups (high, moderate, low adherence). Adherence to visiting a dietitian and appropriate weight gain were assessed as yes or no. Chi-square, ANOVA, and odds ratios were used to compare groups. High dietary adherence compared to low adherence was associated with reduced oral hypoglycaemic and insulin use (OR = 0.55, CI = 0.30–1.00). Visiting a dietitian compared to not was associated with increased oral hypoglycaemic and insulin use (OR = 2.96, CI = 1.12–7.80), decreased odds of a large-for-gestational-age infant (OR = 0.32, CI = 0.14–0.73) and neonatal hyperbilirubinaemia (OR = 0.27, CI = 0.08–0.95). Greater than recommended compared with recommended weight gain was associated with increased oral hypoglycaemic and insulin use (OR = 2.51, CI = 1.26–5.01), while lower than recommended weight gain was associated with decreased postpartum haemorrhage (OR = 0.45, CI = 0.23–0.91) and increased breastfeeding (OR = 1.96, CI = 1.04–3.70). Adherence to dietary recommendations for women with GDM likely improves health outcomes.     

Increased matrix metalloproteinase-9 activity in unstable carotid plaques. A potential role in acute plaque disruption

BACKGROUND AND PURPOSE: Acute disruption of atherosclerotic plaques precedes the onset of clinical syndromes, and studies have implicated a role for matrix metalloproteinases (MMPs) in this process. The aim of this study was to establish the character, level, and expression of MMPs in carotid plaques and to correlate this with clinical status, cerebral embolization, and histology. METHODS: Plaques were obtained from 75 consecutive patients undergoing carotid endarterectomy and divided into 4 groups according to symptomatology (group 1, asymptomatic; group 2, symptomatic >6 months before surgery; group 3, symptomatic within 1 to 6 months; group 4, symptomatic within 1 month). All patients underwent preoperative and intraoperative transcranial Doppler monitoring. Plaques were subjected to histological examination and quantification of MMPs by zymography and ELISA. RESULTS: The level of MMP-9 was significantly higher in group 4 (median 125.7 ng/mL for group 4, median <32 ng/mL for all other groups; P=0.003), with no difference in the levels of MMPs 1, 2, or 3. Furthermore, the MMP-9 concentration was significantly higher in plaques undergoing spontaneous embolization (P=0.019) and those with histological evidence of plaque instability (P<0.03). In situ hybridization demonstrated increased MMP-9 expression in highly symptomatic plaques in areas of intense inflammatory infiltrate. CONCLUSIONS: The concentration, production, and expression of MMP-9 is significantly higher in unstable carotid plaques. If this proves to be a causal relationship, MMP-9 may be a strong candidate for pharmacotherapy aimed at stabilizing plaques and preventing stroke.     

A comparison of two intensities of warfarin for the prevention of recurrent thrombosis in patients with the antiphospholipid antibody syndrome

Many patients with the antiphospholipid antibody syndrome and recurrent thrombosis receive doses of warfarin adjusted to achieve an international normalized ratio (INR) of more than 3.0. However, there are no prospective data to support this approach to thromboprophylaxis.     

Antenatal magnesium sulphate neuroprotection in the preterm infant

Very preterm infants have high rates of neurological impairments and disabilities. These rates have not diminished as the survival rates have improved. Basic science research suggests that magnesium sulphate before birth can be neuroprotective for the preterm fetus. Some, but not all, observational studies in humans also suggest a protective effect of antenatal magnesium sulphate on cerebral palsy. Four randomised controlled trials of antenatal magnesium sulphate have reported long-term neurological effects in surviving infants, but only one of these was designed specifically to evaluate the long-term effects of treatment. These studies found that, overall, antenatal magnesium sulphate therapy had no significant effect on paediatric mortality or neurological outcomes in the first few years of life, including cerebral palsy, but it was found to lower the rate of motor problems at 2 years of age in one study. The role for antenatal magnesium sulphate therapy as a neuroprotective agent for the preterm fetus is not yet established.     

In vivo degradation of porous poly(propylene fumarate)/poly(DL-lactic-co-glycolic acid) composite scaffolds

This study investigated the in vivo degradation of poly(propylene fumarate) (PPF)/poly(DL-lactic-co-glycolic acid) (PLGA) composite scaffolds designed for controlled release of osteogenic factors. PPF/PLGA composites were implanted into 15.0mm segmental defects in the rabbit radius, harvested after 12 and 18 weeks, and analyzed using histological techniques to assess the extent of polymer degradation as well as the tissue response within the pores of the scaffolds. Polymer degradation was limited to micro-fragmentation of the scaffold at the ends and edges of the implant at both 12 and 18 weeks. The tissue within the pores of the scaffold consisted of fibrous tissue, blood vessels and some inflammatory cells. In areas where polymer breakdown was evident, an increased inflammatory response was observed. In contrast, areas of bone ingrowth into the polymer scaffold were characterized by minimal inflammatory response and polymer degradation. Our results show that minimal degradation of porous PPF occurs within 18 weeks of implantation in a rabbit model. Further, the in vivo degradation data of porous PPF/PLGA scaffolds are comparable with earlier obtained in vitro data.     

The use of ITS1 rDNA PCR in detecting pathogenic African trypanosomes

There are 11 different pathogenic trypanosomes in trypanosomiasis endemic regions of Africa. Their detection and characterisation by molecular methods relies on species-specific primers; consequently several PCR tests have to be made on each sample. Primers ITS1 CF and ITS1 BR, previously designed to amplify the internal transcribed spacer (ITS1) of rDNA, have been evaluated for use in a universal diagnostic test for all pathogenic trypanosomes. Blood was collected from 373 cattle and 185 camels. The primers gave constant PCR products with the stocks of each taxon tested. Members of subgenus Trypanozoon (T. brucei brucei, T. evansi, T. b. rhodesiense and T. b. gambiense) gave a constant product of approximately 480 bp; T. congolense, savannah 700 bp, T. congolense kilifi 620 bp and T. congolense forest 710 bp: T. simiae 400 bp, T. simiae tsavo 370 bp, T. godfreyi 300 bp and T. vivax 250 bp. The sensitivity of the test ranged from 10 pg for Trypanozoon, T. congolense clade and T. vivax to 100 pg for T. simiae and T. godfreyi. The primers detected cases of multi-taxa samples, although the sensitivity was reduced with an increase in the combinations. A better detection rate of trypanosome DNA was recorded with buffy coats than from direct blood. With the field samples, the diagnostic sensitivity was close to the sensitivity obtained using single reactions with species-specific primers for Trypanozoon 38/40 (95%) and T. congolense savannah 30/33 (90.9%) but was lower with T. vivax 25/31 (77.4%). The primers offer promise as a routine diagnostic tool through the use of a single PCR; however, further evaluation is recommended.