Role of prenatal cardiovascular magnetic resonance imaging in determining pregnancy risk in repaired Tetralogy of Fallot patients

Funding Acknowledgements

Type of funding sources: None.

Addressing pregnancy risks poses as a new challenge among women with repaired tetralogy of Fallot (TOF). The high-output state of pregnancy may predispose women to late complications of repaired TOF. However, guidelines regarding antenatal and or perinatal cardiovascular assessment has not been outlined. Noninvasive modalities such as cardiac magnetic resonance imaging (CMR) that do not require the utilization of ionizing radiation are feasible methods of assessment. Risk stratification of baseline CMR parameters has been sparsely investigated among repaired TOF cohorts. This study aims to identify baseline CMR parameters that may predict adverse outcomes of pregnancy among women with repaired TOF.

Sixty-five successful pregnancies were recorded from a cohort of 105 pregnant episodes. Patients with CMR studies performed within 5 years prior to delivery events were included. Adverse clinical outcomes of interest included arrhythmia, heart failure admissions, gestational hypertension, pre-eclampsia toxemia and all-cause mortality. Baseline CMR parameters regarding ventricular mechanics such as left and right ventricular end-diastolic and end-systolic volumes, left and right ventricular ejection fractions and pulmonary regurgitant fraction were measured, and their association with adverse clinical outcomes were evaluated using an independent-samples t-test.

Within all 65 successful pregnancies, 26 baseline CMR images were obtained and included in this study. The mean maternal age was 29.7 ± 6.7 years old with a mean birth weight of 2.91 ± 0.49 kg at a mean gestational age of 38.4 ± 2.0 weeks. There was a total of 12 patients with adverse clinical outcome: 5 patients with heart failure hospitalizations, 4 patients with gestational hypertension, 4 patients with arrhythmia and 2 patients with pre-eclampsia toxemia.

Assessment of baseline CMR parameters of ventricular mechanics revealed that increased left ventricular end-diastolic volumes (LVEDV) (144.7mL/m2 ± 4.9; P = 0.011), left ventricular end-systolic volumes (LVESV) (65.1mL/m2 ± 9.4; P = 0.004), right ventricular end-diastolic volumes (RVEDV) (235.2 ± 29.0; P = 0.021) and right ventricular end-systolic volumes (RVESV) (122.2mL/m2 ± 38.1; P = 0.033) were associated with an increased incidence of arrhythmia during pregnancy. Nonetheless, there was no significant association between baseline ventricular mechanics with heart failure, gestational hypertension, and pre-eclampsia toxemia. 

Baseline assessment of cardiac magnetic resonance imaging among pregnant TOF women revealed that larger left and right ventricular volumes were associated with arrythmia development during pregnancy. Further studies with larger cohort sizes evaluating the role of antenatal and perinatal cardiovascular imaging assessment using CMR in predicting the risks of cardiovascular complications during pregnancy are warranted.

Incidence, clinical correlates and associated outcomes of dementia in heart failure: a population-based cohort study

Funding Acknowledgements

Type of funding sources: None.

Background

Dementia, in the setting of heart failure (HF), portends poorer outcomes and poses great challenges in its clinical management.

Purpose

We investigated the incidence, types, clinical correlates, and the prognostic impact of dementia in a population-based cohort of patients with HF. Further, we examined the interactions of age and sex, and education status with dementia incidence.

Methods

The previously validated Hong Kong Clinical Data Analysis Reporting System (CDARS), a territory-wide database was interrogated to identify patients with HF (N= 202,121) from 1995 to 2018. Associations of clinical correlates with incident dementia and its risk with all-cause mortality were assessed using competing risk/multivariable Cox regression models where appropriate.

Results

Among a total cohort aged ≥18 years with HF (mean age: 75.3 ± 13.0 years, 51.3% women), new-onset dementia occurred in 22,145 (11.0%) over a median follow-up of 5.5 years. Alzheimer’s disease occurred in 27.0%; vascular dementia (18.1%) and unspecified dementia (in 55.1%). Age-standardized rate of dementia incidence in women was 1297 (95%CI, 1276-1318) (vs. 744, 95%CI, 723-765) per 10000 population in men. Other independent predictors of dementia include: Increasing age (HR 1.08), Female sex (HR 1.19), Nil/< primary (vs tertiary) education (HR 1.29), Parkinson’s disease (HR 1.73), head injury (HR 1.37), peripheral vascular disease (HR 1.31), stroke (HR 1.29), depression (HR 1.18), alcohol intake (HR1.17), anaemia (HR 1.14), hypertension (HR 1.08), among other common comorbidities in HF (Figure 1A).

Notably, a significant interaction (p < 0.001) between age and sex on dementia incidence was observed, such that women in all age groups were observed to have higher sHR compared to men (Figure 1B). After accounting for competing risk, dementia was not associated with adjusted hazard of all-cause mortality.

Conclusions

Female sex, lower socioeconomic status, increasing age and common comorbidities were associated with higher hazards of incident dementia. Abstract Figure 1A and Figure 1B

Prognostic value of pre-operative left atrial strain on composite endpoint in patients received aortic valve replacement for severe aortic stenosis: a retrospective cohort study

Funding Acknowledgements

Type of funding sources: None.

Objective

Severe aortic stenosis (AS) is the most common primary valvular heart disease, treatable only by aortic valve replacement (AVR).  Current literatures have shown that severe AS may precede atrial dysfunction which predicts adverse outcomes.  However, predictive value of pre-operative left atrial (LA) function on post-AVR clinical outcomes is uncertain.  The study aims to evaluate the prognostic value of pre-operative LA strain on post AVR all-cause mortality and heart failure.

Methods

Patients aged 18 years old or above with severe AS were recruited and assessed using speckle-tracking echocardiography pre-operatively.  Severe AS was defined according to 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease.  Peak Atrial Longitudinal Strain (PALS) was measured as a surrogate of LA function.  Patients with underlying pre-operative atrial fibrillation and other severe valvular heart diseases were excluded.  High PALS was defined as PALS higher than 15.94%. Patients were followed up until death or end of the study. The primary endpoint is a composite endpoint of all-cause mortality and heart failure during hospitalisation. The association of LA function with composite endpoint of all-cause mortality and heart failure was evaluated by Cox Proportional Hazards analysis.

Results

A total of 128 patients (mean age 65.3.9 ± 9.4 years, 56.3% male) were analysed. Patients were followed up for a mean period of 3.9 ± 2.4years.  A total of 65 of 128 patients (50.8%) belonged to low PALS group.  During the study period, 23 patients developed events on the composite endpoint.  Among those with composite endpoint, low PALS group accounted for 18 (78.3%) patients and high PALS group accounted for 5 (21.7%) patients.  Higher PALS was independently associated with lower risk of composite endpoint of all-cause mortality and heart failure (HR, 0.33; 95% CI 0.117-0.916, p = 0.03) after adjustment for EuroSCORE II.

Conclusion

Higher PALS, a surrogate of LA function, is associated with a lower risk of composite endpoints of mortality and heart failure in patients with severe AS undergoing AVR, independent of EuroSCORE II. Evaluation of LA function by assessing speckle tracking derived PALS may aid in prognostication for patients undergoing AVR.

Chronic kidney disease begets heart failure and vice versa; temporal associations between heart failure events in relation to incident chronic kidney disease

Funding Acknowledgements

Type of funding sources: None.

Background

Diabetes, chronic kidney disease (CKD) and heart failure (HF) are fast-growing causes of morbidity and mortality worldwide. Diabetes is an optimal model to study the inter-play of cardiovascular disease and renal disease.

Purpose

To investigate the association of CKD with HF and its prognosis in a large, population-based cohort of diabetes, in which incident CKD and HF events were ascertained longitudinally.

Methods

A population-based cohort of patients aged ≥18 years with diabetes, but without CKD, HF or acute kidney injury at baseline was identified from the previously validated territory-wide Clinical Data Analysis Reporting System between 2000 and 2015. Patients were followed up through December 31,2020 for incident CKD and/or HF or all-cause mortality. Multi-state modelling was used to examine the association of the subgroups (with/without CKD or HF).

Results

Among 294,413 patients (mean age: 65 ± 14 years; 49.5% women), new-onset CKD occurred in 51,583, in whom one-fifth (21.3%) had HF. In contrast, among 28,335 patients with new-onset HF, nearly two-fifth (38.7%) had CKD (Figure 1A). Median duration from baseline to incident CKD was shorter than incident HF [8.27 (4.69-11.97) years vs. 8.76 (5.28-12.37) years, p <0.001]. However, median duration for incident event of HF after CKD diagnosis was 2.15 (0.83-4.50) years and 1.73 (0.62-3.87) years for incident CKD after HF diagnosis. The incidence rate of CKD and HF was 20.39 per 1000 person-years and 10.61 per 1000 person-years, respectively.

Presence of CKD was associated with incident HF (odds ratios [OR] 1.27 [95%CI 1.21-1.33]), and HF with incident CKD (OR 1.26 [95%CI 1.18-1.33]). The presence of both CKD and HF (regardless of which comes first) portends higher risk (6 to 8-fold hazards) of all-cause mortality than neither condition (Figure 1B).

Conclusions

Incident HF occurs in one-fifth of patients with new-onset CKD, and CKD occurs in about 40% with new-onset HF. CKD seems to precede HF. More research on the inter-play of these dual conditions is warranted in view of the high mortality risk. Abstract Figure.

Serial echocardiography assessment and clinical outcomes among pregnant women with Tetralogy of Fallot

Funding Acknowledgements

Type of funding sources: None.

Following advancements in intracardiac repair of Tetralogy of Fallot (TOF), a greater proportion of patients survive well beyond child-bearing age. Pulmonary regurgitation (PR) and subsequent progressive right ventricular dilatation occur frequently as an intrinsic complication of surgical repair of TOF. High-output states such as pregnancy may exacerbate these late complications. The advocation of pre-pregnancy pulmonary valve replacement to mitigate pregnancy-related cardiac burden has remained controversial. This study aims to delineate the outcomes of pregnancy among women with repaired TOF.

105 pregnant episodes among were identified from a cohort of 240 adult female patients with TOF between 1990 to 2021. Patients with echocardiographic studies performed within 1 year prior to and following delivery were included for cardiac functional analysis. A paired sample t-test was performed to compare echocardiographic parameters between pre-delivery and post-delivery periods. Linear regression was used to identify changes to identify significant changes in echocardiographic parameters among patients with a baseline of severe PR.

Within all pregnant episodes (n = 105), 65 successful pregnancies, 16 spontaneous miscarriages, 21 termination of pregnancies and 3 ectopic pregnancies were recorded. The mean maternal age was 28.9 (±6.7) years with deliveries at 37.86 (30-41) gestational weeks. Cardiovascular events occurred in 19 pregnancies with 4 patients having gestational hypertension, 4 patients with pre-eclampsia toxemia, 7 patients with heart failure symptoms and 4 patients with arrhythmias. Other complications included 4 patients with gestational diabetes mellitus, 3 patients with impaired glucose tolerance, 2 patients with anemia, 3 patients with maternal thyroid disease and 1 patients with proteinuria.

Echocardiographic studies demonstrated significant changes in left ventricular ejection fraction (LVEF) (Pre-delivery = 60.69 ±8.73; post-delivery = 59.39 ±9.36) (P = 0.007), left ventricular end diastolic volume (LVEDV) (Pre-delivery: 89.71mL ±18.22mL; Post-delivery: 80.96mL ±12.32mL; P = 0.007), left end systolic volume (LVESV) (Pre-delivery: 35.43 ±12.36; Post-delivery: 32.70 ± 8.83; P = 3.7x10-5) and right ventricular index of myocardial performance score (Pre-delivery: 0.34 ±0.12; Post-delivery: 0.33 ±0.12; P = 0.007). Patients with severe PR was found to have significantly worse right ventricular global longitudinal strain (RV GLS) (P = 0.029). 2 patients progressed to severe PR following delivery.

Adult female patients with TOF can have viable pregnancies with acceptable mortality and morbidity. Deterioration in echocardiographic parameters were identified when comparing between pre-delivery and post-delivery studies. TOF patients should be closely monitored throughout and post-delivery for detection of deterioration of cardiac function and clinical symptoms.

The evolving characteristics and outcomes of acute myocardial infarction in Hong Kong, 1999–2018

Background

The burden of myocardial infarction (MI) with its assorted comorbid complications is increasing parallel to rising life expectancy. Careful characterisation of patient characteristics and identification of short- and long-term complications is critical to their management. Nonetheless, data on the evolving profiles of patient features and outcomes, particularly in an Asian population, remain sparse.

Purpose

We aim to describe the evolving characteristics and outcomes of MI patients in Hong Kong in the past 2 decades.

Methods

From a well-validated territory-wide database in Hong Kong, we included patients with incident acute MI from 1999/01/01 to 2018/12/31. The primary outcome was 30-day all-cause death, while secondary outcomes include haemorrhagic stroke, and pneumonia, at both 30 days and 5 years. Temporal trends in baseline characteristics were evaluated using Poisson regression, while trends in outcomes were evaluated using Cox proportional hazard model, adjusted with demographics, comorbidities, and baseline medications.

Results

A total of 130,218 patients (age 73.6±13.9 years, 40.0% female) were included. Over time, while there was no change in the proportion of females (P=0.196), the increase in mean age (APC 0.23% [0.21 to 0.24], P<0.001) was concordant with the increase in mean CCI (APC 5.1%, [4.8 to 5.3], P<0.001), with more patients suffering from baseline comorbidities (Figure 1; range of APC 1.7% to 4.3%; all P<0.001). The proportion of ST elevation increased significantly (APC 2.5% [2.4 to 2.5], P<0.001).

The adjusted all-cause 30-day mortality rate decreased increased significantly (APC 0.3% [0.1 to 0.5], P=0.005). The increasing trend was significant in older patients (≥70 years), non-ST elevation, and female, while there was a decreasing trend mortality rate in ST elevation and young patients; no significant trend was observed in male. Strikingly, there is an alarming increase in the rate of haemorrhagic stroke (APC 3.4% [2.3 to 4.4], P<0.001) and pneumonia (APC 1.5% [1.3 to 1.7], P<0.001) at 30 days (Figure 2). Although the rate of 5-year all-cause death declined slightly (APC −0.8% [−0.9 to −0.6], P<0.001), there were increasing rates of haemorrhagic stroke (APC 1.0% [0.3 to 1.7], P=0.004) and pneumonia (APC 3.8% [3.6 to 4.1], P<0.001). Patients who were older, had ST elevation, and more comorbid were more likely to develop pneumonia.

Conclusions

Patients with MI have evolved to be older and more comorbid. Alarmingly, despite reduction in long-term all-cause death over time, the reduction was small; risk of death in short-term significantly increased and patients suffer from more complications including haemorrhagic stroke and pneumonia. These results highlight the emergence of extra-cardiac outcomes that drive poor prognosis and accentuate the need to develop tailored strategies to tackle these potentially lethal complications.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Shenzhen Key Medical Discipline; The Sanming Project of HKU-SZH Cardiology

Prognostic value of a novel index: computational pressure-flow dynamics derived fractional flow reserve in patients with stable coronary artery disease treated with optimal medical therapy alone

Background

The use of fractional flow reserve (FFR) is limited due to the need of invasive pressure wire and hyperaemic stimulus. Computational pressure-flow dynamics derived fractional flow reserve (caFFR) is a novel non-invasive index to determine the FFR in patients with stable coronary artery disease (CAD).

Purpose

The clinical value of caFFR remains uncertain. The aim of the study is to evaluate the prognostic role of caFFR in patients with stable CAD who were treated by optimal medical therapy alone.

Methods

A total of 558 stable CAD patients (mean age=64.5±11.2, 59.0% male) with ≥1 coronary lesion detected during conventional coronary angiogram were included. All of them did not undergo percutaneous coronary intervention and were treated with optimal medical therapy alone. Patients were then classified into 4 groups according to their caFFR value; caFFR ≤0.70 (n=40), caFFR = 0.71–0.80 (n=28), caFFR = 0.81–0.90 (n=292), caFFR = 0.91–1.00 (n=198), with a lower caFFR indicating a greater magnitude of myocardial ischemia. The primary endpoint was 3-year major adverse cardiac events (MACE), defined as a composite of all-cause mortality, myocardial infarction or any unplanned revascularization.

Results

During a median follow-up of 36 months, a total of 49 composite events occurred, including 27 all-cause mortality, 4 myocardial infarction and 18 unplanned revascularization.

After multivariate adjustment, caFFR was an independent predictor of MACE (adjusted hazard ratio [HR] = 0.97 per 0.01 increase in caFFR; 95% confidence interval [Cl], 0.95–0.99; P<0.01), all-cause mortality (adjusted HR = 0.96 per 0.01 increase in caFFR; 95% Cl, 0.94–0.99; P<0.01), and stroke (adjusted HR = 0.95 per 0.01 increase in caFFR; 95% Cl, 0.90–0.99; P=0.03).

The area under the curve (AUC) by receiver-operating characteristic curve analysis (ROC) is 0.70 (95% Cl, 0.62–0.78; P<0.01). The optimal cut-off of caFFR defined by ROC analysis for predicting MACE is 0.80, concluding that patients with caFFR ≤0.80 have significantly higher adverse event rate, which is consistent with the cut-off from wire-based FFR.

Using caFFR = 0.91–1.00 as reference, the risk of MACE was highest in patients with caFFR ≤0.70 (adjusted HR = 4.65; 95% Cl, 1.81–11.94; P<0.01), followed by caFFR = 0.71–0.80 (adjusted HR = 3.67; 95% Cl, 1.12–11.33; P=0.02). The risk of MACE was nonetheless similar among patients with caFFR >0.8 (adjusted HR = 1.39; 95% Cl, 0.61–3.19, P=0.44).

Conclusion

In patients with stable CAD who were treated with optimal medical therapy alone, those with more significant myocardial ischemia, indicated by lower caFFR, had higher risks of adverse outcomes. The finding thus supports the use of this non invasive index to quantify the severity of myocardial ischemia, improve risk-stratification, and predict adverse outcomes in patients with stable CAD.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): The University of Hong Kong, Queen Mary Hospital

Prognostic value of longitudinal assessment of hepatorenal function and nutritional status in patients undergoing valvular heart surgery

Background

Hepatorenal dysfunction and malnutrition are frequent extracardiac consequences of valvular heart disease (VHD) and have emerged as prominent drivers of adverse prognosis in selected valvular interventions. Nonetheless, data in a general VHD population is sparse, and their interaction and changes following valvular surgery remain unexplored.

Purpose

We aim to characterise the temporal changes, interaction, and prognostic implications of hepatorenal dysfunction and malnutrition before and after valvular surgery.

Methods

Baseline and temporal changes in hepatorenal dysfunction (assessed by the modified model for end-stage liver disease [MELD-XI] score) and nutritional status (assessed by Controlling Nutritional Status [CONUT] score) were correlated with adverse events (composite of all-cause mortality and hospitalisation for heart failure) using Cox proportional hazards model, adjusted with clinical and echocardiographic covariates, medications, type of valvular procedure, and cardiac surgery risk-stratification models (EuroSCORE II and STS score).

Results

Our study included 909 patients who underwent valvular surgery. At baseline, 216 (24%) and 554 (61%) had hepatorenal dysfunction (MELD-XI >12.43) and malnutrition (CONUT ≥2), respectively. MELD-XI scores were modestly correlated with CONUT scores (R=0.36, p<0.001), with concomitant hepatorenal dysfunction and malnutrition present in 177 (19%) patients.

Over a median follow-up of 4.1 years, 101 (11%) patients died and 119 (13%) were hospitalised for heart failure. There was a stepwise increase in mortality (χ2 89.1, p<0.001) and adverse events (χ2 92.9, p<0.001) from patients with normal hepatorenal function and nutrition to concomitant hepatorenal dysfunction and malnutrition (Figure 1). This association remained consistent in fully adjusted models. MELD-XI and CONUT scores significantly improved the discriminatory accuracy of EuroSCORE II (area under the curve [AUC]: 0.80 vs 0.73, p<0.001) and STS score (AUC: 0.79 vs 0.72, p=0.004) for all-cause mortality.

In patients with MELD-XI and CONUT scores 1 year after surgery (n=707), ΔMELD-XI (follow-up MELD-XI minus baseline MELD-XI score) and ΔCONUT scores were significantly associated with adverse events (HR 1.08, 95% CI 1.03–1.14, p=0.001 for ΔMELD-XI; HR 1.18, 95% CI 1.02–1.35, p=0.02 for ΔCONUT). Patients remaining with hepatorenal dysfunction and malnutrition experienced worse survival (log-rank χ2 65.2, p<0.001) and adverse events (log-rank χ2 90.4, p<0.001) (Figure 2).

Conclusions

In patients undergoing valvular surgery, hepatorenal function and nutritional status at baseline, and their temporal changes, are strongly linked to clinical outcomes. These results highlight the role of hepatorenal and nutritional assessment for risk-stratification in valvular surgery.

Funding Acknowledgement

Type of funding sources: None. Figure 1Figure 2

Association between non-wire based computational angiography fractional flow reserve treatment threshold and major adverse cardiac events in patients with stable coronary artery disease

Introduction

Despite class IA guideline recommendations, the use of fractional flow reserve (FFR) in guiding percutaneous coronary intervention (PCI) in stable coronary artery disease (CAD) patients remains low due to limitations including the need of guidewire placement and hyperaemic stimulus. A novel non-invasive index, computational pressure-flow dynamics derived FFR (caFFR), was developed for measuring functional myocardial ischemia and overcoming the limitations of FFR. However, the clinical relevance of caFFR remains to be investigated. In the present study, we aim at evaluating the prognostic value of caFFR among stable CAD patients.

Methods

We retrospectively included patients with stable CAD who underwent coronary angiography during 2014–2016 at our center. Based on the caFFR value, patients were considered to be ischemic (caFFR ≤0.8) and non-ischemic (caFFR >0.8). Further, we recombined the patients to form the adherence cohort, where patients were defined as adherent-to-caFFR if they were ischemic with PCI or non-ischemic without PCI, and nonadherent-to-caFFR if they were ischemic without PCI or non-ischemic with PCI. The primary endpoint was major adverse cardiac events (MACE), defined as a composite of all-cause mortality, non-fatal myocardial infarction, and any revascularization. Inverse probability of treatment weighting was used to account for treatment selection bias (PCI vs without PCI, or adherent vs non-adherent), and Cox proportional hazard model was used to evaluate the association with MACE.

Results

A total of 1322 patients, 782 patients in the ischemic cohort and 540 patients in the non-ischemic cohort respectively, were included in our analysis. PCI was associated with a lower risk of MACE in the ischemic cohort (hazard ratio [HR] 0.52; 95% confidence interval [CI], 0.34–0.80; P=0.002), but was not associated with MACE in the non-ischemic cohort. In the adherence cohort, adherent-to-caFFR group (n=803) had a lower risk of MACE compared with nonadherent-to-caFFR group (n=566) (HR, 0.61; 95% CI, 0.44–0.85; P=0.003).

Conclusion

Our study is the first to demonstrate the prognostic value of caFFR, a non-wire based assessment of myocardial ischemia, in patients with stable CAD undergoing PCI. These findings support the use of caFFR that bears the potential of a wider adoption compared with wire-based FFR through a reduction in procedure time, risk and costs.

Funding Acknowledgement

Type of funding sources: None. Weighted Kaplan-Meier curvesWeighted Cox proportional hazards model

Trends and sex differences in characteristics and outcomes in myocardial infarction: a 20-year analysis

Background

There are considerable sex differences in patients with myocardial infarction (MI). However, the recent temporal trends in characteristics and outcomes in women vs. men, particularly in an Asian population, remain poorly understood.

Purpose

We aim to evaluate the sex differences in characteristics and outcomes, and how have these differences evolved over the past 2 decades in patients with MI.

Methods

From a well-validated territory-wide database in Hong Kong, we included patients with incident acute MI from 1999/01/01 to 2018/12/31. Outcomes of interest include, at 30 days, all-cause death, new-onset heart failure (HF), and ischaemic stroke. Trends in sex differences in baseline characteristics were evaluated using linear and Poisson regression, while differences in outcomes were evaluated using Cox proportional hazard model, adjusted with demographics, comorbidities, and baseline medications. A Fine-Gray model was used to evaluate HF and ischaemic stroke to account for competing risk, with all-cause death defined as competing event.

Results

A total of 130,218 patients (age 73.6±13.9 years, 40.0% female) were included. Women were older (79.5±11.7 vs. 69.6±13.8 years, P<0.001) and had a more pronounced increasing trend in age over time (interaction P<0.001). Women were also more comorbid overall (Charlson Comorbidity Index [CCI] 1.25 vs 0.85, age-adjusted P<0.001), but the rising trend in CCI over time was less pronounced than in men (interaction P<0.001) (Figure 1). Women had more baseline hypertension, diabetes, and severe renal disease than men (age-adjusted P<0.001), while the increasing trends in these comorbidities were all more pronounced in men than in women (all interaction P<0.001). Women were more likely to have ST-elevation overall (P<0.001).

Although the crude 30-day mortality rate was higher in women (32.6% vs 23.9%), after adjustment for confounders, they had a lower risk of death (hazard ratio [HR] 0.97, 95% CI [0.96 to 0.99], P=0.003). There was no significant difference in the decreasing trend in 30-day mortality between both sexes (interaction P=0.787) (Figure 1). Women had a higher risk of developing HF (HR 1.04 [1.01 to 1.08], P=0.012) and ischemic stroke (HR 1.36 [1.24 to 1.48], P<0.001) in 30 days.

Among patients aged ≤55 (N=15,324), women (N=2,161, 14.1%) had higher risks of all-cause death (HR 1.61 [1.40 to 1.85], P<0.001), HF (HR 1.64 [1.17 to 2.32], P=0.004), and ischemic stroke (HR 1.69 [1.14 to 2.51], P=0.010) in 30 days, even after adjustment for covariates. The excess mortality in women declined over time (interaction P=0.002).

Conclusions

Women MI patients were older and more comorbid compared to men, which contributed to the higher risk of death, HF, and ischemic stroke among women. Among young MI patients, the increased risk for adverse outcomes among women was particularly pronounced, though the sex differences in mortality reduced over time.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): The Shenzhen Key Medical DisciplineThe Sanming Project of HKU-SZH Cardiology

Prognostic value of per-vessel treatment adherence in stable coronary artery disease based on novel computational pressure-flow dynamics derived fractional flow reserve

Background

Computational pressure-flow dynamics derived fractional flow reserve (caFFR) is a novel index developed to evaluate the extent of myocardial ischemia in patients with coronary artery disease (CAD), which eliminates the need of invasive pressure guidewire and hyperaemic stimulus in conventional fractional flow reserve (FFR) measurement. Studies have shown improved clinical outcomes associated with adherence to functional myocardial ischemia assessment when deciding to perform percutaneous coronary intervention (PCI) at a per-patient level. However, the clinical significance of such treatment adherence at a per-vessel level remains uncertain.

Methods

A total of 928 patients (mean age 66.2±10.5, male 72.7%) with stable CAD were included in this study. The caFFR of all three major coronary vessels were obtained for every patient, and the FFR threshold of 0.8 was adopted as the threshold for caFFR to indicate functionally significant artery stenosis which warrants PCI, and vice versa. Based on the caFFR of each major coronary vessel and whether PCI was performed to the respective vessel, patients were stratified into 0–1 vessel with treatment adherence group (group 1) (n=105), 2 vessels with treatment adherence group (group 2) (n=338), and 3 vessels with treatment adherence group (group 3) (n=485). The primary endpoint was major adverse cardiac events (MACE), defined as a composite of all-cause mortality, non-fatal myocardial infarction and any subsequent revascularization.

Results

The severity of CAD based on SYNTAX score assessment was 18.6±10.2 in group 1, 14.6±8.9 in group 2, and 11.5±9.9 in group 3 (P<0.001). The rates of MACE at 3 years were significantly different across groups 1, 2 and 3 (17.1% vs. 12.1% vs. 7.4%; P=0.004). With reference to group 3, the risk of MACE at 3 years was increased in group 2 (adjusted hazard ratio [HR]=1.597; 95% confidence interval [CI]=1.020–2.501; P=0.041), and further increased in group 1 (adjusted HR=1.933; 95% CI=1.081–3.457; P=0.026).

Conclusion

In stable CAD patients, the risk of MACE is incremental when fewer major coronary vessels are treated with adherence to caFFR threshold of 0.8. Per-vessel treatment adherence significantly affects clinical outcomes in terms of MACE.

Funding Acknowledgement

Type of funding sources: None.

Long-term prognostic implications of PCI in ACS patients without ischemia on the basis of computational pressure-flow dynamics derived fractional flow reserve

Background

A substantial proportion of patients with acute coronary syndrome (ACS) may have intermediate lesion that are non-ischemic during emergency coronary angiography. The prognosis of such patients, compared to those with stable ischemic heart disease (SIHD) without ischemic lesion is however uncertain. Recently, a novel index, computational pressure-flow dynamics derived fractional flow reserve (caFFR), has been developed to assess myocardial ischemia, without the need of invasive pressure wire and hyperaemic stimulus as required in conventional fractional flow reserve (FFR). By utilizing caFFR to assess for ischaemic status during coronary angiography, the aim of our study is first to assess the prognostic difference between ACS and SIHD with non-ischaemia intermediate lesions. Second, we ascertain whether PCI in patients with ACS with non-ischaemia intermediate lesions provides survival benefit in addition to medical therapy.

Methods

We retrospectively recruited 551 patients (mean age 64.4 years; male 59.9%) with absence of myocardial ischaemia, defined as caFFR ≥0.80 in all vessels, from our Hospital. Patients were stratified into those with index presentation of ACS (n=132) and those with SIHD (n=491). Among the ACS cohort, patients were further divided into those with PCI (n=83) and with medical therapy alone (n=49). The SIHD cohort (n=491), all of whom were treated with medical therapy alone, was considered as referent group. The primary end point was major adverse cardiovascular events (MACE) at 3 years, which was defined as a composite of all-cause mortality, non-fatal myocardial infarction (MI), and any unplanned revascularization.

Results

During a median follow-up of 36 months, 54 composite events occurred, including 38 all-cause mortality, 5 MI, and 14 unplanned revascularization. Compared to those with SIHD, patients with ACS was independently associated with MACE even in the absence of myocardial ischaemia (adjusted Hazard Ratios=2.531; 95% confidence interval=1.397–4.586; P=0.002). The 3-year incidence rate of MACE was the highest in ACS patients with medical therapy alone, followed by ACS patients with immediate PCI; the SIHD cohort had the lowest incidence rates (30.6% vs 12.0% vs 5.9%, P<0.001). This was mainly driven by the rate of all-cause death (26.5% vs 12.0% vs 3.1%; P<0.001). Similar findings were observed for hospitalisation due to heart failure (14.3% vs 6.0% vs 3.1%, P=0.031) and cardiac death (8.2% vs 4.8% vs 0.4%, P<0.001) at 3 years.

Conclusion

In patients with intermediate lesion without myocardial ischaemia (defined as caFFR ≥0.8), those presented with ACS had a higher risk of MACE at 3 years compared to SIHD. Among ACS patients with intermediate lesion without myocardial ischaemia, PCI significantly reduces the rate of MACE. In patients with ACS, our finding suggests that PCI should be advocated to intermediate lesion even without myocardial ischaemia.

Funding Acknowledgement

Type of funding sources: None. Kaplan-Meier curve for MACECumulative Events at 3 Years

Adult-onset nasopharyngeal diphtheria: an uncommon but rapidly progressive and potentially fatal infection

Nasopharyngeal diphtheria is an acute infectious upper respiratory tract disease caused by toxigenic strains of Corynebacterium diphtheriae. We report a case of a young adult who presented to us with a short history of fever, sore throat, hoarseness of voice and neck swelling. He claimed to have received all his childhood vaccinations and had no known medical illnesses. During laryngoscopy, a white slough (or membrane) was seen at the base of his tongue. The epiglottis was also bulky and the arytenoids were swollen bilaterally. The membrane was sent to the microbiology laboratory for culture. A diagnosis of nasopharyngeal diphtheria was made clinically and the patient was treated with an antitoxin together with erythromycin, while awaiting the culture result. Nevertheless, the patient's condition deteriorated swiftly and although the laboratory eventually confirmed an infection by toxin-producing C. diphtheriae, the patient had already succumbed to the infection.

Vaccine hesitancy and the resurgence of vaccine preventable diseases: the way forward for Malaysia, a Southeast Asian country

This study engaged health professionals in in-depth, semi-structured interviews to explore their opinions concerning the issues surrounding vaccine hesitancy in Malaysia and strategies to improve vaccination to stamp the rise of vaccine preventable diseases (VPDs). Opinions on how to address the resurgence of VPDs in the era of increasing vaccine hesitancy were obtained. Eight health professionals, including geriatricians, pediatricians, microbiologists, public health specialists, and family medicine specialists were interviewed. The influence of anti-vaccination propaganda, past-experience of adverse event following immunization (AEFI), perceived religious prohibition, a belief that traditional complementary and alternative medicine (TCAM) use is safer, pseudoscience beliefs, and anti-vaccine conspiracy theories were identified as reasons for refusing to vaccinate. The interplay of social, cultural and religious perspectives in influencing perceived religious prohibition, pseudoscience beliefs, and the use of TCAM contributing to vaccine refusal was found. Five broad themes emerged from the health professionals regarding strategies to address vaccine hesitancy, including establishing an electronic vaccination registry, increasing public awareness initiatives, providing feedback to the public on the findings of AEFI, training of front-line healthcare providers, and banning the dissemination of anti-vaccine information via social media. With regards to identifying strategies to address the resurgence of VPDs, mandatory vaccination received mixed opinions; many viewed supplementary immunization activity and the prevention of travel and migration of unvaccinated individuals as being necessary. In conclusion, the present study identified unique local cultural, traditional and religious beliefs that could contribute to vaccine hesitancy in addition to issues surrounding vaccination refusal similarly faced by other countries around the world. This information are important for the formulation of targeted intervention strategies to stamp vaccine hesitancy in Malaysia which are also a useful guide for other countries especially in the Southeast Asia region facing similar vaccine hesitancy issues.

Genetic Basis of Attenuation of Cold-Adapted Influenza Strain B/Leningrad/14/17/55 - Backup Master Donor Virus for Influenza Type B Live Attenuated Vaccines

The reassortant vaccine strain of live attenuated influenza vaccine inherits temperature sensitivity and areactogenicity from cold-adapted attenuated master donor virus. In Russia, B/ USSR/60/69 master donor virus (B60) is currently in use for the preparation of live attenuated type B influenza vaccine candidates. Trivalent live attenuated influenza vaccine based on A/ Leningrad/134/17/57 and B60 are licensed for the use in Russia for single dose vaccination of adults and children over 3 years. B/Leningrad/14/17/55 (B14) cold-adapted virus is a backup master donor virus for live attenuated type B influenza vaccine. According to our preliminary estimates, it is more attenuated than B60, which can allow expanding applicability of this vaccine for children under 3 years of age. In this paper, the role of B14 genes in its attenuation was assessed. Representative collection of reassortants of B14 with epidemic influenza B viruses was obtained, a phenotypic analysis of reassortants was performed, and their pathogenicity for animals was assessed. The leading role of PB2 and PA genes in attenuation of B14 master donor virus was proven.

Barriers to implementing a national health screening program for men in Malaysia: An online survey of healthcare providers

INTRODUCTION

This study aimed to determine the views and practices of healthcare providers and barriers they encountered when implementing the national health screening program for men in a public primary care setting in Malaysia.

METHODS

An online survey was conducted among healthcare providers across public health clinics in Malaysia. All family medicine specialists, medical officers, nurses and assistant medical officers involved in the screening program for adult men were invited to answer a 51-item questionnaire via email or WhatsApp. The questionnaire comprised five sections: participants' socio-demographic information, current screening practices, barriers and facilitators to using the screening tool, and views on the content and format of the screening tool.

RESULTS

A total of 231 healthcare providers from 129 health clinics participated in this survey. Among them, 37.44% perceived the implementation of the screening program as a "top-down decision." Although 37.44% found the screening tool for adult men "useful," some felt that it was "time consuming" to fill out (38.2%) and "lengthy" (28.3%). In addition, 'adult men refuse to answer' (24.1%) was cited as the most common patient-related barrier.

CONCLUSIONS

This study provided useful insights into the challenges encountered by the public healthcare providers when implementing a national screening program for men. The screening tool for adult men should be revised to make it more user-friendly. Further studies should explore the reasons why men were reluctant to participate in health screenings, thus enhancing the implementation of screening programs in primary care.

Vaccine hesitancy and the resurgence of vaccine preventable diseases: the way forward for Malaysia, a Southeast Asian country

This study engaged health professionals in in-depth, semi-structured interviews to explore their opinions concerning the issues surrounding vaccine hesitancy in Malaysia and strategies to improve vaccination to stamp the rise of vaccine preventable diseases (VPDs). Opinions on how to address the resurgence of VPDs in the era of increasing vaccine hesitancy were obtained. Eight health professionals, including geriatricians, pediatricians, microbiologists, public health specialists, and family medicine specialists were interviewed. The influence of anti-vaccination propaganda, past-experience of adverse event following immunization (AEFI), perceived religious prohibition, a belief that traditional complementary and alternative medicine (TCAM) use is safer, pseudoscience beliefs, and anti-vaccine conspiracy theories were identified as reasons for refusing to vaccinate. The interplay of social, cultural and religious perspectives in influencing perceived religious prohibition, pseudoscience beliefs, and the use of TCAM contributing to vaccine refusal was found. Five broad themes emerged from the health professionals regarding strategies to address vaccine hesitancy, including establishing an electronic vaccination registry, increasing public awareness initiatives, providing feedback to the public on the findings of AEFI, training of front-line healthcare providers, and banning the dissemination of anti-vaccine information via social media. With regards to identifying strategies to address the resurgence of VPDs, mandatory vaccination received mixed opinions; many viewed supplementary immunization activity and the prevention of travel and migration of unvaccinated individuals as being necessary. In conclusion, the present study identified unique local cultural, traditional and religious beliefs that could contribute to vaccine hesitancy in addition to issues surrounding vaccination refusal similarly faced by other countries around the world. This information are important for the formulation of targeted intervention strategies to stamp vaccine hesitancy in Malaysia which are also a useful guide for other countries especially in the Southeast Asia region facing similar vaccine hesitancy issues.

Adrenomedullin increases the short-circuit current in the rat prostate: Receptors, chloride channels, the effects of cAMP and calcium ions and implications on fluid secretion

In this study, we have investigated the effects of adrenomedullin on chloride and fluid secretion in the rat prostate. The presence of adrenomedullin (ADM) in rat prostate was confirmed using immunostaining, and the molecular species was determined using gel filtration chromatography coupled with an enzyme-linked assay for ADM. The effects of ADM on fluid secretion were studied by short-circuit current technique in a whole mount preparation of the prostate in an Ussing chamber. The results indicated that the ADM level was higher in the ventral than the dorso-lateral prostate and the major molecular species was the active peptide. ADM increased the short-circuit current through both the cAMP- and calcium-activated chloride channels in the ventral lobe, but only through the calcium-activated channels in the dorso-lateral lobe. These stimulatory effects were blocked by the calcitonin gene-related peptide (CGRP) receptor antagonist, hCGRP8-37. We conclude that ADM may regulate prostatic fluid secretion through the chloride channels, which may affect the composition of the seminal plasma bathing the spermatozoa and hence fertility.

Effects of adrenomedullin on tumour necrosis factor alpha, interleukins, endothelin-1, leptin, and adiponectin in the epididymal fat and soleus muscle of the rat

Adrenomedullin (ADM) is a peptide hormone, which participates in the development of metabolic syndrome. In this study, we have investigated the interaction of ADM and cytokines, endothelin-1 (EDN-1) and adipokines in the epididymal fat and the soleus muscle. Epididymal fat and soleus muscles from adult male Sprague-Dawley rat were incubated with ADM at concentration of 100 nM for the study of the gene expression and secretion of tumour necrosis factor (TNF-α), EDN-1, leptin, adiponectin, interleukin 1β (IL-1β), and IL-6. The effects of TNF-α and EDN-1 on ADM gene expression and secretion were also investigated. The results showed that ADM decreased the gene expression and protein secretion of TNF-α in both the epididymal fat and the soleus muscle and decreased IL-1β gene expression and secretion in the soleus muscle. It also decreased endothelin gene expression and adiponectin gene expression and release and increased IL-6 and leptin gene expression and secretion in the epididymal fat. These effects were effectively blocked by the calcitonin gene-related peptide (CGRP) receptor antagonist, hCGRP8-37, but not by the ADM receptor antagonist, hADM22-52. The reduction of inflammatory cytokines and EDN-1 may help to decrease insulin resistance and increase glucose uptake. As TNF-α also increases ADM levels in the epididymal fat and the soleus muscle and EDN-1 also increases ADM levels in the epididymal fat, they may form a feedback loop with ADM in these tissues. The increase in leptin and the decrease in adiponectin by ADM in the epididymal fat may have opposite effects on metabolism.

An ontogenic study of adrenomedullin gene expression in the rat lung, adrenal, kidney, and heart

In this study, the gene expression of adrenomedullin (Adm) in the peripheral tissues which include lung, adrenal, kidney, and heart during development was investigated in the rat. The preproadrenomedullin (preproAdm) mRNA and mRNAs of its related receptor components, calcitonin receptor-like receptor (Crlr), and receptor activity-modifying proteins (Ramp1, 2 and 3) of the lung, adrenal, kidney, and heart were measured by real-time RT-PCR and the ADM peptide measured by radioimmunoassay in 1-, 7-, 21-day-old rats and the adult rats. From day 1 to 21, preproAdm mRNA levels increased with age in the lung, the kidney, and the heart but decreased with age in the adrenal. ADM levels, however, increased with age in the lung but decreased with age in the kidney, the adrenal, and the heart. The preproAdm levels in the lung, in the kidney, and in the adrenal all increased in the adult rat. ADM peptide levels, however, decreased in the adult rat. Crlr and Ramp2 gene expression increased with age in the lung, in the kidney, and in the heart but decreased with age in the adrenal in the prepubertal rats. The results indicate that the levels of preproAdm mRNA, ADM peptide and its receptor component mRNAs in different tissues followed different patterns of changes during development.

Randomized clinical trial of perioperative systemic warming in major elective abdominal surgery

BACKGROUND

Hypothermia is common in the operating theatre and may increase susceptibility to postoperative complications. Intraoperative systemic warming has been shown to improve outcomes of surgery. This study aimed to examine the effects of additional perioperative systemic warming on postoperative morbidity.

METHODS

All patients admitted for elective major abdominal surgery and fulfilling the inclusion criteria were randomized into control or warming groups. Both groups were warmed during surgery, but patients in the warming group were additionally warmed 2 h before and after surgery using a conductive carbon polymer mattress.

RESULTS

The trial recruited 103 patients (56 in the control group, 47 in the warming group). Both groups were well matched for age, sex and clinical state. Patients in the warming group had lower blood loss (median 200 (range 5-1000) ml versus median 400 (range 50-2300) ml in the control group; P = 0.011) and complication rates (15 (32 per cent) of 47 versus 30 (54 per cent) of 56 in the control group; P = 0.027). There were three deaths; two in the control group (P = 0.566).

CONCLUSION

Extending systemic warming to the perioperative period had additional beneficial effects, with minimal additional cost and patient discomfort.

Antibiotic regimens for secondary peritonitis of gastrointestinal origin in adults

BACKGROUND

Secondary peritonitis is associated with a high mortality rate and if not treated successfully leads to development of abscesses, severe sepsis and multi-organ failure. Source control and adjunctive antibiotics are the mainstay of treatment. However, no conclusive evidence suggest that one antibiotic regimen is better than any other but at the same time have a lower toxicity.

OBJECTIVES

To ascertain the efficacy and adverse effects of different antibiotic regimens in treating intra-abdominal infections in adults. Outcomes were divided into primary (clinical success and effectiveness in reducing mortality) and secondary (microbiological success, preventing wound infection, intra-abdominal abscess, clinical sepsis, remote infection, superinfection, adverse reactions, duration of treatment required, effectiveness in reducing hospitalised stay, and time to defervescence).

SEARCH STRATEGY

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (Cochrane Library, Issue 4, 2004), MEDLINE (from 1966 to November 2004), EMBASE (from 1980 to November 2004) and Cochrane Colorectal Cancer Group specialised register SR-COLOCA. Bibliographies of identified studies were screened for further relevant trials.

SELECTION CRITERIA

Randomised and quasi-randomised controlled trials comparing different antibiotic regimens in the treatment of secondary peritonitis in adults were selected. Trials reporting gynaecological or traumatic peritonitis were excluded from this review. Ambiguity regarding suitability of trials were discussed among the review team.

DATA COLLECTION AND ANALYSIS

Six reviewers independently assessed trial quality and extracted data. Data collection was standardised using data collection form to ensure uniformity among reviewers. Statistical analyses were performed using the random effects model and the results expressed as odds ratio for dichotomous outcomes, or weight mean difference for continuous data with 95% confidence intervals.

MAIN RESULTS

Fourty studies with 5094 patients met the inclusion criteria. Sixteen different comparative antibiotic regimens were reported. All antibiotics showed equivocal comparability in terms of clinical success. Mortality did not differ between the regimens. Despite the potential high toxicity profile of regimens using aminoglycosides, this was not demonstrated in this review. The reason for this could be the inherent bias within clinical trials in the form of patient selection and stringency in monitoring drug levels.

AUTHORS' CONCLUSIONS

No specific recommendations can be made for the first line treatment of secondary peritonitis in adults with antibiotics, as all regimens showed equivocal efficacy. Other factors such as local guidelines and preferences, ease of administration, costs and availability must therefore be taken into consideration in deciding the antibiotic regimen of choice. Future trials should attempt to stratify patients and perform intention-to-treat analysis to allow better external validity.

Utilization of custom electron bolus in head and neck radiotherapy

Conventional methods of treating superficial head and neck tumors, such as the wedge pair technique or the use of multiple electron fields of varying energies, can result in excellent tumor control. However, in some cases, these techniques irradiate healthy tissue unnecessarily and/or create hot and cold spots in junction regions, particularly in patients with complex surface contour modification or varying planning target volume (PTV) thickness. The objective of this work is to demonstrate how bolus electron conformal therapy can be used for these patients. Two patients treated using this technique are presented. The first patient was diagnosed with malignant fibrous histiocytoma involving the right ear concha and was treated with 12-MeV electrons. The second patient was diagnosed with acinic cell carcinoma of the left parotid gland and was treated with 20-MeV electrons after having undergone a complete parotidectomy. Each patient's bolus was designed using bolus design tools implemented in an in-house treatment-planning system (TPS). The bolus was fabricated using a computer-controlled milling machine. As part of the quality assurance process to ensure proper fabrication and placement of the bolus, the patients underwent a second computed tomography (CT) scan with the bolus in place. Using that data, the final dose distribution was computed using the Philips Pinnacle(3) TPS (Philips Medical Systems, Andover, MA). Results showed that the 90% isodose surface conformed well to the PTV and that the dose to critical structures such as cord, brain, and lung was well below tolerance limits. Both patients showed no evidence of disease six months post-radiotherapy. In conclusion, electron bolus conformal therapy is a viable option for treating head and neck tumors, particularly patients having a variable thickness PTV or surface anatomy with surgical defects.

Does sperm morphology play a significant role in increased sex chromosomal disomy? A comparison between patients with teratozoospermia and OAT by FISH

Eight semen samples from men with teratozoospermia (T), along with samples from 3 men with normal fertility and 5 samples from men with oligoasthenoteratozoospermia (OAT) were analyzed for X and Y chromosomal anomalies with the use of fluorescently labeled centromeric probes. This study was undertaken to determine whether patients with abnormal sperm morphology (teratozoospermia) have increased or decreased incidence of a sex chromosomal anomaly. The sex chromosome disomy for the T samples was 0.36% and for the OAT group it was 0.61%, compared with baseline value for the normozoospermia group (0.09%).

Neurocognitive effects of therapeutic irradiation for base of skull tumors

PURPOSE

To determine whether radiation therapy delivered to the paranasal sinuses causes any long-term impairment in neurocognitive function as a result of incidental brain irradiation.

METHODS AND MATERIALS

Nineteen patients who received paranasal sinus irradiation at least 20 months and up to 20 years before assessment were given a battery of neuropsychologic tests of cognitive function. Radiation was delivered by a three-field (one anteroposterior and two lateral) technique. The median radiation dose was 60 Gy (range 50-68 Gy) in fractions of 1.8 to 2 Gy. The volume of irradiated brain was calculated from planning computed tomography slices or simulation films. The results of the neuropsychologic tests were compared to normative control values.

RESULTS

Memory impairment was found in 80% of the patients, and one-third manifested difficulty with visual-motor speed, frontal lobe executive functions, and fine motor coordination. Two of the patients had frank brain necrosis with resultant dementia and blindness, and three had evidence of brain atrophy. Three of the fourteen patients without documented cerebral atrophy or necrosis were disabled from their normal activities. Three patients also developed pituitary dysfunction. Neurocognitive symptoms were related to the total dose of radiation delivered but not to the volume of brain irradiated, side of radiation boost, or chemotherapy treatment. The pattern of test findings was consistent with radiation injury to subcortical white matter.

CONCLUSIONS

Radiation therapy for paranasal sinus cancer may cause delayed neurocognitive side effects. Currently, however, the development of severe adverse effects appears to be decreasing because of improvements in the techniques used to deliver radiation. Lowering the total dose and improving dose distributions should further decrease the incidence of delayed brain injury due to radiation.

Immunohistochemical localization of type-II (AT2) angiotensin receptors with a polyclonal antibody against a peptide from the C-terminal tail

A polyclonal antibody has been prepared against a synthetic peptide derived from the C-terminal tail of the cloned rat AT2 angiotensin receptor, corresponding to amino acid residue 341-351. The antibody was of high titer and displayed monospecific activity toward the synthetic peptide in the ELISA assay. Western blot analysis indicated that the antiserum recognised only a single protein band with a mean apparent molecular mass of 75.4 kDa in the rat adrenals. Immunohistochemical studies with affinity purified antibody localised immunoreactive AT2 angiotensin receptor in medulla cells of the adrenals. Immunoreactivity was also observed in pyramidal tract, but no specific immunoreactivity can be detected in regions of rat brain that are known to express AT2 angiotensin receptors, including inferior olive, locus coeruleus and cerebellum.

Acute injuries in off-road bicycle racing

A descriptive study was conducted to investigate injuries sustained at a major off-road bicycling race at Mammoth Mountain, California, July 6 to 10, 1994. A total of 4027 individual starts in five events during the race were reported. Overall, the total number of competitors in the 5 events was 3624, with some cyclists participating in multiple events. Injuries were considered significant if they occurred during competition and prevented the rider from completing the event. Sixteen cyclists had injuries that met these criteria for an overall injury rate of 0.40%. These 16 cyclists had 44 injuries. Abrasions were the most common injury, followed by contusions, lacerations, fractures, and concussions. The mean injury severity score was 3.0 (range, 1 to 5) with 81.2% of the injuries resulting from cyclists going downhill. Injuries were more severe when the riders were thrown from the bicycles (P = 0.03). We observed different mechanisms of injury in various events, suggesting that the risk factors for sustaining a traumatic injury may vary according to the type of competition involved.

Water bolus for electron irradiation of the ear canal

PURPOSE

To demonstrate that water bolus in the external ear can decrease the dose inhomogeneity caused by auricular surface irregularities when the ear is in an electron-beam field.

METHODS AND MATERIALS

Three-dimensional (3D) dose distributions with and without water bolus in the external ear were calculated for a representative patient. The electron dose calculations were made using the Hogstrom pencil beam algorithm as implemented in 3D by Starkschall. To demonstrate the use of water bolus in the ear clinically, the case of a patient with squamous carcinoma of the concha who was treated with electrons is presented.

RESULTS

Water bolus markedly lessens the dose heterogeneity caused by the surface irregularities of the ear and the air in the external auditory canal. In the test case, the maximum dose was reduced by 25% using this technique.

CONCLUSION

When the ear is in an electron beam field, warm water should be placed in the external auditory canal and concha. This maneuver may reduce the incidence of auricular complications that occur after electron-beam therapy.

Low-calcium diets increase both production and clearance of 1,25-dihydroxyvitamin D3 in rats

Administration of large doses of 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] to animals induces 1,25(OH)2D3 side-chain oxidative pathways. This study determined if the elevated plasma 1,25(OH)2D3 seen in rats fed low-Ca diets is associated not only with an increased production rate (PR) but also with an increased metabolic clearance rate (MCR) of the hormone. In vitamin D-replete rats fed a Ca-deficient diet for 3-4 wk, the PR increased 21-fold, plasma levels 15-fold, and the MCR by 37%. The increased MCR in Ca-deficient rats was associated with a 48% increase in hepatic microsomal UDP glucuronyl transferase enzyme activity, whereas 1,25(OH)2D3 catabolism by homogenates of liver and small intestinal mucosa was unchanged. In contrast to the effects of low-Ca diets, acute (7 h) pharmacological elevation of plasma 1,25(OH)2D3 to 1.5 ng/ml in normal rats did not influence the MCR. Thus chronically elevated 1,25(OH)2D3 levels are necessary to stimulate clearance. In conclusion, 1,25(OH)2D3 clearance in rats can be stimulated not only by chronic pharmacological doses of 1,25(OH)2D3 but also by the physiological stimulus of a low-Ca diet. Hence, plasma 1,25(OH)2D3 levels can be regulated by changes in both PR and MCR.