BACKGROUND: 'Masked Hypertension' is a phenomenon of blood pressure that is normotensive by clinic measurement but proves to be hypertensive by 24 hour-AMBP and is associated with many cardiovascular complications and its clinical importance has become the center of public interest. However, in Korea no study concerning masked hypertension has ever been published so far. We investigated the frequency and the related factors of masked hypertension among Koreans. METHODS: Overall, 53 volunteers from Incheon and Seoul, Korea, who were 40 years old and abov were enrolled from August 2003 to August 2004. We checked their blood pressure and pulse rate every hour using an ambulatory blood pressure monitoring device [SpaceLabs 90207] for 24 hours. Masked hypertension was defined as office mean BP less than 140/90 mmHg and daytime mean BP over 135/85 mmHg. RESULTS: Among the total, 15 subjects met the criteria of masked hypertension (28.3%) Current smoking (P=0.021), higher clinic mean SBP (P=0.011) and DBP (P=0.027), and prehypertension (P=0.04) were identified as related factors. And when adjusted for sex by logistic regression, only current smoking was statistically significant (P=0.039) and prehypertension showed borderline significance (P=0.092) (CI=95%). Additionally, mean pulse pressures and mean standard deviation of individual mean SBP were higher in the masked hypertension group. CONCLUSION: The frequency of masked hypertension was 28.3% the and related factors were current smoking and higher office BP, especially prehypertension that was introduced in JNC-7. The fact that the pulse pressure and the variability of individual SBP were higher in the masked hypertension group remains thought-provoking.
Adult ; Blood Pressure ; Blood Pressure Monitoring, Ambulatory ; Heart Rate ; Humans ; Incheon ; Korea ; Logistic Models ; Masked Hypertension* ; Masks* ; Prehypertension ; Seoul ; Smoke ; Smoking ; Volunteers*

Phase transformation, superelastic characteristics and variation of surface residual stress were studied for Nitinol shape memory alloy through application of UNSM technology, and life extension methods of stent were also studied by using elastic resilience and corrosion resistance. Nitinol wire of Oslash1.778 mm showed similar surface roughness before and after UNSM treatment, but drawing traces and micro defects were all removed by UNSM treatment. It also changed the surface residual stress from tensile to compressive values, and XRD result showed less intensive austenite peak and clear martensite and additional R-phase peaks after UNSM treatment. Fatigue resistance could be greatly improved through removal of surface defects and rearrangement of surface residual stress from tensile to compressive state, and development of surface modification system to improve not only bio-compatability but also resistance to corrosion and wear will make it possible to develop vascular stent which can be used for circulating system diseases which run first cause of death of recent Koreans.
Alloys ; Cause of Death ; Corrosion ; Dental Alloys ; Fatigue ; Life Expectancy ; Memory ; Stents ; Ultrasonics