Association between obstructive sleep apnea severity and endothelial dysfunction in an increased background of cardiovascular burden.

The objective of this study is to examine whether increasing obstructive sleep apnea (OSA) severity is associated with worsening endothelial function. The design is a cross-sectional examination of the baseline assessment of a multi-centre randomized controlled clinical trial examining the effects of oxygen, continuous positive airway pressure (CPAP) therapy or lifestyle modifications on cardiovascular biomarkers. Participants were recruited from cardiology clinics at four sites. Participants with an apnea-hypopnea index (AHI) of 15-50 and known cardio/cerebrovascular disease (CVD) or CVD risk factors were included. OSA severity indices [oxygen desaturation index (ODI), AHI and percentage of sleep time below 90% oxygen saturation (total sleep time <90)] and a measure of endothelium-mediated vasodilatation [Framingham reactive hyperaemia index (F-RHI) derived from peripheral arterial tonometry (PAT)] were assessed. The sample included 267 individuals with a mean AHI of 25.0 ± 8.5 SD and mean F-RHI 0.44 ± 0.38. In adjusted models, the slope of the relationship between ODI and F-RHI differed above and below an ODI of 24.6 (P = 0.04), such that above an ODI of 24.6 there was a marginally significant decline in the geometric mean of the PAT ratio by 3% [95% confidence interval (CI): 0%, 5%; P = 0.05], while below this point, there was a marginally significant incline in the geometric mean of the PAT ratio by 13% (95% CI: 0%, 27%; P = 0.05) per 5-unit increase in ODI. A similar pattern was observed between AHI and F-RHI. No relation was noted with total sleep time <90 and F-RHI. There was evidence of a graded decline in endothelial function in association with higher levels of intermittent hypoxaemia.

Obstructive sleep apnea and diurnal nondipping hemodynamic indices in patients at increased cardiovascular risk.

RATIONALE: We hypothesized increasing obstructive sleep apnea (OSA) severity would be associated with nondipping blood pressure (BP) in increased cardiovascular disease (CVD) risk. METHODS: Baseline data from 298 cardiology patients recruited for a multicenter randomized controlled trial were examined. Dipping was defined as a sleep-related BP or heart rate (HR) reduction of at least 10%. Logistic regression models were fit, adjusting for age, sex, race, BMI, CVD risk factors, CVD, and study site. RESULTS: There was a statistically significant 4% increase in the odds of nondipping SBP per 1-unit increase in both apnea hypopnea index (AHI) and oxygen desaturation index (ODI). There was no significant relationship between AHI and nondipping mean arterial pressure (MAP); however, a 3% increase in the odds of nondipping MAP per 1-unit increase in ODI was observed [odds ratio (OR) = 1.03; 95% confidence interval (CI) 1.00-1.05]. At severe OSA levels, a 10 and 4% increase in odds of nondipping DBP per 1-unit increase in AHI and ODI were observed, respectively. A 6% [OR = 1.06; 95% CI (1.01-1.10)] increase in nondipping HR odds was observed with each increase in ODI until the upper quartile of ODI. CONCLUSION: In patients at cardiovascular risk and moderate-to-severe OSA, increasing AHI and/or ODI were associated with increased odds of nondipping SBP and nondipping MAP. More severe levels of AHI and ODI also were associated with nondipping DBP. These results support progressive BP burden associated with increased OSA severity even in patients managed by cardiology specialty care.

A young female with an unusual cause of dyspnea.

Within the context of coronary artery anomalies, coronary fistulas are classified by termination. A coronary artery fistula (CAF) involves a sizable communication between a coronary artery and a heart chamber (coronary-cameral fistula) or a segment of the systemic or pulmonary system (coronary artery arteriovenous fistula). These are often due to deviations from normal embryological development. CAF may be present in patients at any age, but is usually suspected in early childhood and accounts for 0.08-0.4% of congenital cardiac anomalies. They may also be acquired by trauma or from invasive cardiac procedures. The majority of CAF arises from the right coronary artery (55%) and the left anterior descending coronary artery, with the circumflex rarely involved. The outcome of these connections depends upon the termination site. The pathophysiology of these lesions is identical. Coronary artery anomalies are difficult to detect clinically. Most are benign but some may produce symptoms that can be life threatening. We present a female with an unusual cause of dyspnea found to have a continuous heart murmur, cardiac catheterization showed an evidence of a long tract arising from the origin of the right coronary artery with flow directed towards the right atrium and the right atrial appendage.

Weight control measures among university students in a developing country: a cultural association or a risk behavior.

OBJECTIVE: The purpose of the study was to determine the prevalence of university students, in Lebanon, trying to lose weight and assess the relation of trying to lose weight with demographic, scholastic and health behavioral factors. METHODS: The study was cross-sectional conducted in the academic year 2000-2001. A proportionate random sample of 2,013 students was selected among five public and private universities in Beirut. Participants completed a self-administered anonymous questionnaire that included questions on trying to lose weight, demographic, scholastic, and health behavioral factors including smoking, alcohol, and seat belt use. Bivariate and stepwise logistic regression analyses were performed to examine the association between trying to lose weight and the above-mentioned characteristics. RESULTS: The overall prevalence of students trying to lose weight was 30%, with 71% of them being under weight or normal weight. Use of medications and inducement of vomiting constituted 12% and 11%, respectively. Stepwise logistic regression analysis showed that the variables significantly associated with trying to lose weight were socio-economical factors rather than risky behaviors. Students who were at increased odds of performing such methods were females OR = (2.08, 95% CI = 1.6-2.5), employed (OR = 1.36, 95% CI = 1.01-1.8), and registered in a private university (OR = 1.69, 95% CI = 1.25-2.0). The major of students was also a significant predictor. CONCLUSION: In Lebanon, weight reduction could be re-enforced by socio-economical factors and not necessarily be an adolescent risk behavior.