Variability in cardiac MR measurement of left ventricular ejection fraction, volumes and mass in healthy adults: defining a significant change at 1 year.

OBJECTIVE: Variability in the measurement of left ventricular (LV) parameters in cardiovascular imaging has typically been assessed over a short time interval, but clinicians most commonly compare results from studies performed a year apart. To account for variation in technical, procedural and biological factors over this time frame, we quantified the within-subject changes in LV volumes, LV mass (LVM) and LV ejection fraction (EF) in a well-defined cohort of healthy adults at 12 months. METHODS: Cardiac MR (CMR) was performed in 42 healthy control subjects at baseline and at 1 year (1.5 T Magnetom® Avanto; Siemens Healthcare, Erlangen, Germany). Analysis of steady-state free precession images was performed manually offline (Argus software; Siemens Healthcare) for assessment of LV volumes, LVM and EF by a single blinded observer. A random subset of 10 participants also underwent repeat imaging within 7 days to determine short-term interstudy reproducibility. RESULTS: There were no significant changes in any LV parameter on repeat CMR at 12 months. The short-term interstudy biases were not significantly different from the long-term changes observed at 1 year. The smallest detectable change (SDC) for LVEF, end-diastolic volume, end-systolic volume and LVM that could be recognized with 95% confidence were 6%, 13 ml, 7 ml and 6 g, respectively. CONCLUSION: The variability in CMR-derived LV measures arising from technical, procedural and biological factors remains minimal at 12 months. Thus, for patients undergoing repeat annual assessment by CMR, even small differences in LV function, size and LVM (which are greater than the SDC) may be attributed to disease-related factors. ADVANCES IN KNOWLEDGE: The reproducibility and reliability of CMR data at 12 months is excellent allowing clinicians to be confident that even small changes in LV structure and function over this time frame are real.

Central pulse pressure in patients with chronic kidney disease and in renal transplant recipients.

Patients with chronic kidney disease (CKD) and renal transplant recipients (RTR) have increased cardiovascular risk. The value of measuring central pulse pressure (cPP) over brachial pulse pressure (pPP) is not known. Central PP was measured in 597 patients (364 CKD:233 RTR). In multivariate analysis, age and female gender positively correlated with cPP; heart rate and estimated glomerular filtration rate negatively correlated with cPP. Associations for age, heart rate and gender persisted after additional adjustment for pPP and aortic wave reflection. This model accounted for 91% of the variability in cPP, with pPP alone accounting for 74%. Results were similar when both patient groups were analysed separately. A subset of patients with CKD had aortic pulse wave velocity (PWV) and left ventricular mass index (LVMI) measured. There were no differences in the univariate correlations between PWV (r=0.368 vs 0.315; P=0.4) or LVMI (r=0.125 vs 0.163; P=0.7); nor in the multivariate models created for PWV (P=0.1) or LVMI (P=0.1) when either cPP or pPP were used. This study demonstrates that in these patients most of the variability in cPP can be explained by pPP. Additionally, cPP does not appear to provide additional information beyond pPP in determining PWV and LVMI.

Understanding the effects of chronic kidney disease on cardiovascular risk: are there lessons to be learnt from healthy kidney donors?

Chronic kidney disease (CKD) is now a recognized global public health problem. It is highly prevalent and strongly associated with hypertension and cardiovascular disease (CVD); far more patients with a glomerular filtration rate below 60 ml min(-1) per 1.73 m(2) will die from cardiovascular causes than progress to end-stage renal disease. A better understanding of the complex mechanisms underlying the development of CVD among CKD patients is required if we are to begin devising therapy to prevent or reverse this process. Observational studies of CVD in CKD are difficult to interpret because renal impairment is almost always accompanied by confounding factors. These include the underlying disease process itself (for example, diabetes mellitus and systemic vasculitis) and the complications of CKD, such as hypertension, anaemia and inflammation. Kidney donors provide an ideal opportunity to study healthy subjects without manifest vascular disease who experience an acute change from having normal to modestly impaired renal function at the time of uninephrectomy. Prospectively examining the cardiovascular consequences of uninephrectomy using donors as a model of CKD may provide useful insight into the pathophysiology of CVD in CKD and, therefore, into how the CVD risk associated with renal impairment might eventually be reduced.

Consultant attitudes to undertaking undergraduate teaching duties: perspectives from hospitals serving a large medical school.

OBJECTIVE: To explore attitudes among National Health Service consultants responsible for delivering basic clinical teaching to medical students. DESIGN: Postal questionnaire. SUBJECTS AND SETTING: A total of 308 acute hospital trust consultants working in 4 'new' and 4 'established' teaching hospitals in the West Midlands metropolitan area, and involved in the delivery of clinical teaching to Year 3 medical students at the University of Birmingham Medical School during 2002-03. MAIN OUTCOME MEASURE(S): The questionnaire explored contractual requirements, actual teaching commitments and perceptions of medical students' knowledge and attitudes. Responses from doctors and surgeons and from respondents working in established and new teaching hospitals were compared. RESULTS: A total of 249 responses were received (response rate 80.8%). Although many consultants enjoy teaching students, their enjoyment and their ability to deliver high standards of teaching are compromised by time and resource constraints. For many the situation is aggravated by the perceived inappropriate organisation of the clinical teaching curriculum and the inadequate preparation of students for clinical practice. Linking these themes is the overarching perception among teachers that neither service nor educational establishments afford teaching the levels of recognition and reward associated with clinical work or research. CONCLUSION: To overcome barriers to teaching requires more reciprocal links between hospital staff and medical schools, opportunities for consultants to understand and to comment on curricular and timetable developments, and, perhaps most importantly, recognition (in contractual, financial, managerial and personal terms) of the importance of undergraduate teaching in the competing triad of service, research and education.

Vena cava injuries during laparoscopic cholecystectomy.

Two instances of vena cava injury occurring during insertion of a new trocar for laparoscopic surgery are presented. The mechanism of injury in each case was identical. These injuries are extremely rare, and fortunately both patients survived. Any new instrument that is purported to be an improvement over existing ones should be critically evaluated so that needless and unnecessary injuries such as these can be avoided.

Immunocytochemical analysis of hormone receptors with malignant cells separated from human mammary tumors.

The authors compared radioligand assays with immunocytochemistry assays to establish the hormone receptor status of malignant mammary tumors. This study differed from previous work in that immunochemistry assays were used with tumor cell effluents rather than with intact histologic sections. The results showed a 90% qualitative agreement between immunocytochemistry assays and radioligand assays in identifying estrogen receptor (ER)- or progesterone receptor (PgR)-positive and ER- or PgR-negative malignant tumors. However, only 31% of the cells from receptor-positive patients expressed ER, and only 24% of the cells contained PgR. The data showed a 73% agreement between immunocytochemistry and radioligand assays for ER when cases were categorized as strongly positive (> 100 fmol/mg and > 10% stained cells), intermediately positive (3-100 fmol/mg and .1% to 10% stained cells), or negative in both assays. Progesterone receptor values for the three categories showed an agreement between assays of 82%. These observations suggest that immunocytochemical analysis of isolated populations of tumor cells may be a useful means of complimenting radioligand assays in selecting patients for antihormone therapy.