MRI measurements of the thoracic aorta and pulmonary artery.

INTRODUCTION: The purpose of this study was to obtain a range of normal measurements of the adult thoracic aorta and main pulmonary artery using cardiac MRI, and to assess agreement between measurements made on ECG-gated two-dimensional (2D) breath held steady-state-free precession (SSFP), and three-dimensional (3D) breath held SSFP image acquisitions. METHODS: Forty-nine normal volunteers underwent cardiac MRI using a 1.5T system. Two independent examiners measured the ascending aorta, aortic arch, descending thoracic aorta and main pulmonary artery in pre-defined locations. RESULTS: Overall, inter-observer agreement for all measurements was excellent. Close agreement was observed in aortic diameters obtained from the 2D and 3D SSFP methods in six of the nine aortic measurement sites. There was a tendency for the 3D measurements to be smaller than the 2D measurements but this was only significant at two sites, the aortic annulus, and the ascending aorta. There was a significance difference in aortic measurements between the left carotid artery (LC) and the left subclavian artery (LSC). CONCLUSION: Normal values for transverse diameters of the thoracic aorta and main pulmonary artery were established using 2D and 3D non-contrast MR sequences in healthy adults. Overall both inter-observer agreement, and agreement between 2D and 3D techniques was good. Mean diameter differences demonstrated at the aortic annulus, ascending aorta and aortic arch between LC and LSC although significant were less than one millimetre and unlikely to be important in clinical practice.

On-board measurements of particle and gaseous emissions from a large cargo vessel at different operating conditions.

This study investigated particle and gaseous emission factors from a large cargo vessel for her whole voyage including at berth, manoeuvring and cruising. Quantification of these factors assists in minimising the uncertainty in the current methods of exhaust gas emission factor estimation. Engine performance and emissions from the main marine engine were measured on-board while the ship was manoeuvring and cruising at sea. Emissions of an auxiliary engine working at 55% of maximum continuous rating (MCR) were measured when the ship was at actual harbour stopovers. Gaseous and particle emission factors in this study are presented in g kWh-1 or # kWh-1, and compared with previous studies. Results showed that the SO2 emission factor is higher than that of previous studies due to the high sulphur content of the fuel used. The particle number size distributions showed only one mode for different operating conditions of the ship, with a peak at around 40-50 nm, which was dominated by ultrafine particles. Emission factors of CO, HC, PM and PN observed during ship manoeuvring were much higher than that of those recorded at cruising condition. These findings highlight the importance of quantification and monitoring ship emissions in close proximity to port areas, as they can have the highest impact on population exposure.

Tenofovir-associated proteinuria.

Proteinuria was observed in 27% of 153 patients taking tenofovir for more than 1 year. Concomitant protease inhibitor therapy and cumulative tenofovir exposure were independently associated with proteinuria in this cohort. Proteinuria was reversible in 11 of 12 patients who ceased tenofovir because of proteinuria without altering other medications. Clinicians should be aware that tenofovir can cause reversible proteinuria in patients with HIV.

Impact of pain location, organ system and treating speciality on timely delivery of analgesia in emergency departments.

OBJECTIVE: This retrospective, observational cohort study investigated whether the clinical features of a patient's pain, including anatomical location, organ system and likely treating speciality, impact on the delivery of analgesia within 30 min in EDs. METHODS: Data were obtained from 24 centres across Australia between April 2008 and March 2009. Principal outcome was delivery of analgesia within 30 min or less. Factors that might explain any differences were analysed, including anatomical location of the pain, likely treating speciality, organ system affected, age, sex, day and time of presentation, hospital location, documented pain score and triage category. Analysis was by the χ(2)-test for independence of proportions and multiple logistic regression. A P-value <0.05 was considered statistically significant. RESULTS: There were 4598 patients, of whom 2578 were male. The median age was 36 years (range 0-103). Both limb origin of pain (χ(2) = 46.1, P < 0.001) and documentation of a pain score (χ(2) = 48.6, P < 0.001) were strongly associated with delivery of analgesia within 30 min. Attending a rural ED was a significant risk factor for delayed analgesia (χ(2) = 12.5, P < 0.001). Burns patients (40.2%, 47 of 117, P < 0.001) and orthopaedic patients (26.1%, 259 of 992, P < 0.001) were much more likely to received analgesia within 30 min than the mean (19.5%, 896 of 4598). CONCLUSIONS: Patients presenting with burns, orthopaedic conditions or with a limb location of pain are more likely to receive analgesia within 30 min in Australian EDs. Clinicians should be aware of possible trends in the delivery of timely analgesia to patients with pain.

A prospective pilot study evaluating the 'cardiac decompensation score' in the setting of intraaortic balloon counterpulsation.

The study objective was to determine whether the 'cardiac decompensation score' could identify cardiac decompensation in a patient with existing cardiac compromise managed with intraaortic balloon counterpulsation (IABP). A one-group, posttest-only design was utilised to collect observations in 2003 from IABP recipients treated in the intensive care unit of a 450 bed Australian, government funded, public, cardiothoracic, tertiary referral hospital. Twenty-three consecutive IABP recipients were enrolled, four of whom died in ICU (17.4%). All non-survivors exhibited primarily rising scores over the observation period (p<0.001) and had final scores of 25 or higher. In contrast, the maximum score obtained by a survivor at any time was 15. Regardless of survival, scores for the 23 participants were generally decreasing immediately following therapy escalation (p=0.016). Further reflecting these changes in patient support, there was also a trend for scores to move from rising to falling at such treatment escalations (p=0.024). This pilot study indicates the 'cardiac decompensation score' to accurately represent changes in heart function specific to an individual patient. Use of the score in conjunction with IABP may lead to earlier identification of changes occurring in a patient's cardiac function and thus facilitate improved IABP outcomes.

Determinants of in-hospital and long-term surgical outcomes after repair of postinfarction ventricular septal rupture.

OBJECTIVES: Surgical repair of post-myocardial infarction ventricular septal rupture is challenging with reported early mortality being substantial. In addition, congestive cardiac failure and ventricular tachyarrhythmia frequently occur long term after the operation, although frequency and predictive factors of these events have been poorly identified. METHODS: A consecutive series of 68 patients who underwent repair of postinfarction ventricular septal rupture by 14 surgeons between 1988 and 2007 was studied. Fifty-eight (85%) patients underwent repair in an urgent setting (<48 hours after diagnosis). Coronary artery bypass grafting was concomitantly performed in 48 (71%) patients. Mean follow-up period was 9.2 +/- 4.9 years. RESULTS: Thirty-day mortality was 35%, with previous myocardial infarction, previous cardiac surgery, preoperative left ventricular ejection fraction less than 40%, and urgent surgery being independent risk factors. Actuarial survival of 30-day survivors was 88% at 5 years, 73% at 10 years, and 51% at 15 years. Actuarial freedom from congestive cardiac failure and ventricular tachyarrhythmia was 70% and 85% at 5 years, 54% and 71% at 10 years, and 28% and 61% at 15 years, respectively. Independent predictors for congestive cardiac failure included hypertension, posterior septal rupture, residual interventricular communication, and preoperative left ventricular ejection fraction less than 40%, whereas concomitant ventricular aneurysmectomy and preoperative occlusion of the left anterior descending artery were independent predictors of ventricular tachyarrhythmia. CONCLUSIONS: Long-term outcomes after surgical repair of postinfarction ventricular septal rupture was favorable, despite infrequent exposure by individual surgeons to the pathologic features, indicating that an aggressive surgical approach is warranted. Predictors of congestive cardiac failure and ventricular arrhythmia long term varied.

Modified RV short axis series--a new method for cardiac MRI measurement of right ventricular volumes.

PURPOSE: The current standard image orientation employed in the MRI assessment of right ventricular volumes uses a series of short axis cine acquisitions located with respect to a horizontal long axis view with the first slice placed across the atrio-ventricular valve plane at end diastole. Inherent inaccuracies are encountered with the use of this image orientation due to difficulty in defining the tricuspid valve and the border between atrium and ventricle on the resultant images. Our experience indicates that because the tricuspid valve is usually not in-plane in the slice the atrio-ventricular margin is difficult to distinguish. This leads to inaccuracies in measurements at the base of the RV and miscalculation of the RV volume. The purpose of this study was to assess an alternative method of image orientation aimed at increasing the accuracy of RV volume measurements using current commercially available CMRI sequences. This technique, the modified RV short axis series, is oriented to the outflow tract of the right ventricle. METHOD: We undertook a prospective study of 50 post cardiac transplant patients. A series of LV short axis multi-slice cine acquisition FIESTA images was acquired using the current standard technique. From this data set, LV and RV stroke volumes were derived on an Advantage Windows workstation using planimetry of the endocardial and epicardial borders in end systole and end diastole. Our new technique involved obtaining a set of multi-slice cine acquisition FIESTA images in a plane perpendicular to a line from the centre of the pulmonary valve to the apex of the RV. Planimetry of the RV was then performed and a stroke volume calculated using the same method of analysis. RV stroke volumes obtained from both techniques were compared with LV stroke volumes. Three operators independently derived RV data sets. RESULTS: On the images acquired with the new technique, the tricuspid valve was easier to define leading to more accurate and reproducible planimetry of ventricular borders. RV stroke volumes calculated from the new method showed better agreement with LV stroke volumes than with the current method. These results were consistent across the three operators. CONCLUSIONS: This new method improves visualisation of the tricuspid valve and makes analysis easier and less prone to operator error than the current standard technique for MRI assessment of RV volumes.