Cross-ethnic comparison of the association between central sleep apnea and atrial fibrillation/flutter: The Kuakini Honolulu-Asia Aging Study and the Osteoporotic Fractures in Men (Mr.OS) study.

INTRODUCTION: Few studies indicated the impact of ethnicity on an association between central sleep apnea (CSA) and atrial fibrillation/flutter (AF) in older populations. We assessed possible ethnic differences in the association among elderly Japanese-American and White-American men. METHODS: We performed a cross-sectional analysis using two population studies of Japanese-American and White-American men. The Kuakini Honolulu-Asia Aging Study is a longitudinal cohort study of Japanese-American men living in Hawaii. Sleep data were collected between 1999 and 2000. The Osteoporotic Fractures in Men (Mr.OS) Sleep Study was conducted between 2003 and 2005 on the continental U.S. The majority of Mr.OS participants were White-American. We selected 79-90 year old males, who had overnight polysomnography from both studies. Total participants were 690 Japanese-American and 871 White-American men. The central apnea index (CAI) was the measure of the number of central apneas. CSA was defined by CAI>=5. Cheyne-Stokes breathing (CSB) was defined as a minimum consecutive 5-10 min period of a crescendo-decrescendo respiratory pattern associated with CSA. RESULTS: The prevalence of AF was 5.7% in Japanese-American men and 9.0% in White-American men. The prevalence of CSA and CSB in White-Americans were higher than in Japanese-Americans (11.5% vs 6.5% and 5.7% vs 3.3%, respectively). In multivariable-adjusted logistic regression models, CSA was associated with higher odds of AF, and the association was stronger in Japanese-Americans [Odds Ratio (OR) = 4.77, 95% confidence interval (CI): 1.95-11.67] than in White-Americans (OR = 2.09, 95 %CI: 1.09-4.01). CSB showed similar trends as CSA. CONCLUSIONS: After adjustment, CSA and CSB were significantly associated with AF in both Japanese-American and White-American men.

Paradoxical association between atrial fibrillation/flutter and high cholesterol over age 75 years: The Kuakini Honolulu Heart Program and Honolulu-Asia Aging Study.

INTRODUCTION: Several studies have indicated high cholesterol is paradoxically associated with low prevalence of atrial fibrillation/flutter (AF). However, the etiology is uncertain. One potential explanation might be the confounding effect of age exemplifying prevalence-incidence (Neyman's) bias. However, this bias has not often been discussed in depth in the literature. Therefore, we conducted a cross-sectional analysis to test the hypothesis that there is a paradoxical association between lipid profile and AF prevalence. METHODS: This is a cross-sectional study design, using data from the Kuakini Honolulu Heart Program. Participants were 3741 Japanese-American men between 71 and 93 years old living in Hawaii. Serum total cholesterol (TC) level was measured and categorized into quartiles. AF was diagnosed by 12­lead Electrocardiogram. We categorized age into quartiles (71-74, 75-77, 78-80 and 81+ years). RESULTS: We observed opposite associations between AF and TC among different age groups. For participants age ≥75, higher TC levels were paradoxically associated with lower prevalence of AF after multivariable adjustment, i.e. the odds ratios of AF comparing the highest TC quartile with the lowest TC quartile for age 75-77, 78-80 and 81+ years were 0.17 (95% confidence interval [CI], 0.06-0.52), 0.28 (95% CI, 0.07-1.09) and 0.14 (95% CI, 0.03-0.62), respectively. Conversely, for those who were 71-74 years old, the odds ratio of AF was 2.09 (95% CI, 0.76-5.75) between the highest and the lowest TC quartiles. CONCLUSIONS: There is a paradoxical association of TC with AF in Japanese-American men age ≥75, but not <75 years. The paradox might be explained by Neyman's bias.

Association between central sleep apnea and atrial fibrillation/flutter in Japanese-American men: The Kuakini Honolulu Heart Program (HHP) and Honolulu-Asia Aging Study (HAAS).

INTRODUCTION: While several studies have indicated that central sleep apnea (CSA) is associated with atrial fibrillation and atrial flutter (AF) in older populations, few studies have focused on older Asian populations. METHODS: We conducted a cross- sectional analysis using data from the 1999-2000, 7th exam cycle of the Kuakini Honolulu-Asia Aging Study. Participants were 718 Japanese-American men between 79 and 97 years old, who had overnight polysomnography. Obstructive Apnea-Hypopnea Index (OAHI) was the measure of the number of obstructive apneas and hypopneas with >4% oxygen desaturation. Additionally, the Central Apnea Index (CAI) was the measure of the number of central apneas. Obstructive sleep apnea (OSA) was categorized as none (OAHI <5), mild (OAHI 5-14), moderate (OAHI 15-29) and severe (OAHI ≥30). CSA was defined by CAI of 5 or more. Cheyne-Stokes Breathing (CSB) was defined as a minimum consecutive 5-minute period of a crescendo-decrescendo respiratory pattern associated with CSA. RESULTS: AF prevalence was 5.5% (39 of 709). The prevalence proportions of severe OSA, CSA, and CSB were 20.2% (143 of 709), 6.4% (43 of 673) and 3.2% (22 of 673), respectively. In multivariable-adjusted logistic regression models, CSA and CSB were significantly associated with AF prevalence: odds ratio (OR) 5.15, 95% confidential interval (CI), 2.21-12.52 and OR 6.26, 95% CI, 2.05-19.14, respectively. However, OSA was not significantly associated with AF prevalence. CONCLUSION: AF prevalence is associated with CSA and CSB but not OSA in older Japanese-American men. This information could help target AF prevention strategies in this population.

Calcified plaque rupture and very late stent thrombosis after bare-metal stent implantation.

Very late stent thrombosis (>1 year: VLST) is a major concern in the drug-eluting stent (DES) era. VLST occurs not only in patients implanted with DESs but also in those implanted with bare-metal stents (BMSs). We examined intravascular ultrasound (IVUS) findings in patients with VLST after BMS implantation. Five consecutive patients presented with VLST as ST elevation myocardial infarction. VLST occurred at a mean of 9.5 years after BMS implantation. In the IVUS findings, the minimum stent area was 7.8 ± 1.2 mm(2). None of the patients had incomplete stent apposition or stent underexpansion, which was defined as a stent expansion index of <0.8. The mean stent expansion index was 1.01. Calcium deposits in the previous stented segment were observed in 4 patients (80%), and a total of 14 calcium deposits were observed in all patients. The calcification pattern was superficial (78.5%) and spotty (57.1%) within a calcium arc of <90°. The mean calcium arc was 72.5° ± 88.5°. A ruptured plaque with an intraluminal flap was detected in all cases. According to the IVUS findings of ruptured plaque and calcium deposits, VLST after BMS might be caused by a thrombus formation subsequent to a calcified atherosclerotic plaque rupture.