Relationship between coffee consumption and prevalence of metabolic syndrome among Japanese civil servants.

BACKGROUND: Metabolic syndrome has become a major worldwide public health problem. We examined the relationship between coffee consumption and the prevalence of metabolic syndrome among Japanese civil servants. METHODS: The study participants were 3284 employees (2335 men and 948 women) aged 20 to 65 years. Using data from their 2008 health checkup records, we analyzed the relationship between coffee consumption and the prevalence of metabolic syndrome. Metabolic syndrome was defined according to the Japanese criteria. RESULTS: Metabolic syndrome was diagnosed in 374 of the 2335 men (16.0%) and 32 of the 948 women (3.4%). In univariate and multiple logistic regression analyses, the odds ratios (ORs) among men for the presence of metabolic syndrome were 0.79 (95% CI: 0.56-1.03) and 0.61 (0.39-0.95), respectively, among moderate (≥4 cups of coffee per day) coffee drinkers as compared with non-coffee drinkers. Among all components of metabolic syndrome, high blood pressure and high triglyceride level were inversely associated with moderate coffee consumption in men, after adjusting for age, body mass index, smoking status, drinking status, and exercise. However, in women, moderate coffee consumption was not significantly associated with the prevalence of metabolic syndrome or its components. CONCLUSIONS: Moderate coffee consumption was significantly associated with lower prevalence of metabolic syndrome in Japanese male civil servants.

Two Cases of Atraumatic Chylous Ascites Characterized by Hypotriglyceridemia and Partially Managed with an Oral Fat-Free Elemental Diet.

Most cases of chylous ascites occur after surgery, but it also develops in nonoperative cases, although rarely. Such cases are often difficult to treat. In this study, we treated 2 cases of atraumatic chylous ascites, which were controlled by combining diuretic treatment with an oral fat-free elemental diet (Elental®, EA Pharma Co., Ltd., Tokyo, Japan). Elental can provide oral nutrition compatible with a lipid-restricted diet, which may be useful for control of chylous ascites. We report on these cases, including literature review-based considerations.

Health Observation App for COVID-19 Symptom Tracking Integrated With Personal Health Records: Proof of Concept and Practical Use Study.

BACKGROUND: As a counter-cluster measure to prevent the spread of the infectious novel coronavirus disease (COVID-19), an efficient system for health observation outside the hospital is urgently required. Personal health records (PHRs) are suitable for the daily management of physical conditions. Importantly, there are no major differences between the items collected by daily health observation via PHR and the observation of items related to COVID-19. Until now, observations related to COVID-19 have been performed exclusively based on disease-specific items. Therefore, we hypothesize that PHRs would be suitable as a symptom-tracking tool for COVID-19. To this end, we integrated health observation items specific to COVID-19 with an existing PHR-based app. OBJECTIVE: This study is conducted as a proof-of-concept study in a real-world setting to develop a PHR-based COVID-19 symptom-tracking app and to demonstrate the practical use of health observations for COVID-19 using a smartphone or tablet app integrated with PHRs. METHODS: We applied the PHR-based health observation app within an active epidemiological investigation conducted by Wakayama City Public Health Center. At the public health center, a list is made of individuals who have been in close contact with known infected cases (health observers). Email addresses are used by the app when a health observer sends data to the public health center. Each health observer downloads the app and installs it on their smartphone. Self-observed health data are entered daily into the app. These data are then sent via the app by email at a designated time. Localized epidemiological officers can visualize the collected data using a spreadsheet macro and, thus, monitor the health condition of all health observers. RESULTS: We used the app as part of an active epidemiological investigation executed at a public health center. During the investigation, 72 close contacts were discovered. Among them, 57 had adopted the use of the health observation app. Before the introduction of the app, all health observers would have been interviewed by telephone, a slow process that took four epidemiological officers more than 2 hours. After the introduction of the app, a single epidemiological officer can carry out health observations. The app was distributed for free beginning in early March, and by mid-May, it had been used by more than 20,280 users and 400 facilities and organizations across Japan. Currently, health observation of COVID-19 is socially recognized and has become one of the requirements for resuming social activities. CONCLUSIONS: Health observation by PHRs for the purpose of improving health management can also be effectively applied as a measure against large-scale infectious diseases. Individual habits of improving awareness of personal health and the use of PHRs for daily health management are powerful armaments against the rapid spread of infectious diseases. Ultimately, similar actions may help to prevent the spread of COVID-19.

Genetic factors associated with elevation of uric acid after treatment with thiazide-like diuretic in patients with essential hypertension.

We investigated changes in blood pressure (BP) and metabolic adverse effects, especially elevation of uric acid (UA), after treatment with a thiazide-like diuretic (TD) in patients with essential hypertension. Furthermore, the role of genetic factors in the elevation of UA by TD was assessed by a 500 K SNP DNA microarray. The subjects included 126 hypertensive patients (57 women and 69 men, mean age 59 ± 12 years) who registered for the GEANE (Gene Evaluation for ANtihypertensive Effects) study. After one month of the nontreatment period, TD, indapamide, angiotensin II receptor antagonist valsartan, and Ca channel blocker amlodipine were administered to all patients for 3 months each in a randomized crossover manner. BP, renal function, serum UA level, and electrolytes were measured at baseline and at the end of each treatment period. Single nucleotide polymorphisms (SNPs) associated with UA elevation after treatment with indapamide were investigated by a genome-wide association study (GWAS). Indapamide significantly decreased both office and home BP levels. Treatment with indapamide also significantly reduced the estimated glomerular filtration rate and serum potassium and increased serum UA. Patients whose UA level increased more than 1 mg/dl showed significantly higher baseline office SBP and plasma glucose and showed greater decline in renal function compared with those who showed less UA increase (<1 mg/dl). Some SNPs strongly associated with an increase in UA after treatment with indapamide were identified. This study is the first report on SNPs associated with UA elevation after TD treatment. This information may be useful for the prevention of adverse effects after treatment with TD.

Endothelial function and oxidative stress in renovascular hypertension.

BACKGROUND: It has been reported that renovascular hypertension activates the renin-angiotensin system, leading to an increase in oxidative stress. We sought to determine whether renal-artery angioplasty improves endothelial dysfunction in patients with renovascular hypertension through a reduction in oxidative stress. METHODS: We evaluated the response of forearm blood flow to acetylcholine, an endothelium-dependent vasodilator, and isosorbide dinitrate, an endothelium-independent vasodilator, before and after renal-artery angioplasty in 15 subjects with renovascular hypertension and 15 controls without hypertension who were matched for age and sex. Forearm blood flow was measured with the use of a mercury-filled Silastic strain-gauge plethysmograph. RESULTS: The forearm blood flow in response to acetylcholine was less in subjects with renovascular hypertension than in controls, although the forearm blood flow in response to isosorbide dinitrate was similar in the two groups. Angioplasty decreased systolic and diastolic blood pressures, forearm vascular resistance, and urinary excretion of 8-hydroxy-2'-deoxyguanosine and serum malondialdehyde-modified low-density lipoprotein (LDL), indexes of oxidative stress. After angioplasty, the mean (+/-SD) forearm blood flow in response to acetylcholine was increased in the patients with renovascular hypertension (19.3+/-6.8 vs. 29.6+/-7.1 ml per minute per 100 ml, P=0.002). The increase in the maximal forearm blood flow in response to acetylcholine correlated significantly with the decrease in urinary excretion of 8-hydroxy-2'-deoxyguanosine (r=-0.51, P=0.004) and serum malondialdehyde-modified LDL (r=-0.39, P=0.02). Coinfusion of ascorbic acid (vitamin C) augmented the response of forearm blood flow to acetylcholine before angioplasty (P<0.001) but not after angioplasty. CONCLUSIONS: These findings suggest that excessive oxidative stress is involved, at least in part, in impaired endothelium-dependent vasodilatation in patients with renovascular hypertension.

Report of the Working Group for Dietary Salt Reduction of the Japanese Society of Hypertension: (1) Rationale for salt restriction and salt-restriction target level for the management of hypertension.

Salt excess is well known to be involved in the pathophysiology of hypertension, and thus restriction of salt intake is widely recommended for management of the disease. Excessive salt intake induces blood pressure (BP)-dependent as well as -independent progression of cardiovascular disease. Although the human body is considered to be adapted to very low salt intake (0.5-3 g/day), restriction to such a low level of salt intake is extremely difficult to accomplish in developed countries. Significant BP reduction has been reported in large-scale clinical studies in which salt intake was decreased to less than 6 g/day, and the results of a meta-analysis have shown that systolic BP was reduced about 1 mmHg with every decrease in salt intake of 1 g/day in hypertensive subjects. Current guidelines for the treatment of hypertension, including Japanese guidelines, recommend dietary salt reduction to 6 g/day or less in hypertensive patients. However, it appears to be fairly difficult to attain this target of salt intake, especially in Japan. There is thus a need for feasible and effective measures to attain this salt restriction target.

Report of the Working Group for Dietary Salt Reduction of the Japanese Society of Hypertension: (2) Assessment of salt intake in the management of hypertension.

Restriction of dietary salt is widely recommended in the management of hypertension, but assessment of individual salt intake has drawn little attention. The understanding of salt intake is important as a guide for optimizing salt-restriction strategies. However, precise evaluation of salt intake is difficult. More reliable methods are more difficult to perform, whereas easier methods are less reliable. Thus, the method to assess salt intake should be determined as the situation demands. The Working Group for Dietary Salt Reduction of the Japanese Society of Hypertension recommends the assessment of individual salt intake using one of the following methods in the management of hypertension. 1) The measurement of the sodium (Na) excretion from 24-h urine sampling or nutritionist's analysis of the dietary contents, which are reliable but difficult to perform, are suitable for facilities specializing in the treatment of hypertension. 2) Estimation of the Na excretion from the Na/creatinine (Cr) ratio in spot urine is less reliable but practical and is suitable for general medical facilities. 3) Estimation using an electronic salt sensor equipped with a calculation formula is also less reliable but is simple enough that patients can use it themselves. The patients are considered to be compliant with the salt-restriction regimen if salt intake measured by whichever method is less than 6 g (100 mmol)/day.

[Calcium intake and cardiovascular diseases].

Although a great bulk of epidemiologic, experimental and clinical studies for relationship between calcium intake and morbidity and mortality of hypertension, coronary heart diseases and cerebrovascular diseases have been undertaken, they failed to obtain the concurrent results. They also failed to reveal the concurrent preventive and therapeutic effects of calcium supplementation on cardiovascular and cerebrovascular diseases. It is recommended to take the required amounts of calcium (> or = 600 mg/day) and magnesium (> or = 300 mg/day) not only for prevention of cardiovascular diseases but also for the general health, and to restrict salt intake.

Low body mass index is a risk factor for impaired endothelium-dependent vasodilation in humans: role of nitric oxide and oxidative stress.

OBJECTIVES: The purpose of this study was to evaluate the relationship between body mass index (BMI), including low BMIs, and endothelial function. BACKGROUND: Epidemiologic study has demonstrated that not only obesity but also a low BMI may be a risk factor for cardiovascular disease. METHODS: The forearm blood flow (FBF) response to acetylcholine (ACh) and isosorbide dinitrate (ISDN) was measured in 87 healthy young men (15 low BMI, 51 normal, 14 obese, and 7 extremely obese). RESULTS: Plasma concentrations of 8-hydroxy-2'-deoxyguanosine and serum concentrations of malondialdehyde-modified low-density lipoprotein were higher in low BMI, obese, and extremely obese subjects than in normal subjects and were similar among the low BMI, obese, and extremely obese groups. The FBF response to ACh was greater in the normal group than in the other groups (p < 0.001), and was lower in the extremely obese group as compared with the other groups (p < 0.001). The ACh-stimulated vasodilation was similar between the low BMI group and the obese group. The ISDN-stimulated vasodilation was similar in all four groups. There were no significant differences in ACh-stimulated vasodilation between the four groups after the nitric oxide (NO) synthase inhibitor NG-monomethyl-L-arginine infusion. Co-infusion of vitamin C augmented the FBF response to ACh in low BMI, obese, and extremely obese groups--but not in normal BMI group. CONCLUSIONS: These findings suggest that not only obesity but also a low BMI may be a risk factor for impaired endothelium-dependent vasodilation through the increased oxidative stress, leading to the reduced bioavailability of NO.

Estrogen replacement suppresses function of thrombin stimulated platelets by inhibiting Ca(2+) influx and raising cyclic adenosine monophosphate.

OBJECTIVE: Estrogen replacement therapy (ERT) in postmenopausal women reduces the risk of cardiovascular diseases. Beneficial changes in lipid profiles account for only one part, thereby raising the question of other estrogen induced benefit that may be lost at menopause. The purpose of this study was to determine the effects of estrogen replacement therapy (ERT) on platelet function of postmenopausal women. METHODS: The effect of 4 weeks ERT (conjugated estrogens 0.625 mg/day) on platelet function was evaluated ex vivo in 18 postmenopausal women (mean age 53 +/- 5 years, after menopause 3.8 +/- 1.9 years). RESULTS: After ERT, (1) plasma concentrations of estrone and estradiol significantly increased (estrone: 16 +/- 7-211+/- 80 pg/ml, estradiol: 14+/- 3-125 +/- 49 pg/ml, P<0.05) and LDL-cholesterol decreased (129 +/- 23-94 +/- 25 mg/dl, P<0.05). Plasma 6-keto-PG F(1) alpha significantly increased (7.2 +/- 3.4-13.3 +/- 6.7 pg/dl, P<0.05). (2) platelet aggregation and positive staining for P-selectin in thrombin- (0.1 and 1.0 U/ml) stimulated platelets were inhibited (Th 0.1 U/ml: 4.0 +/- 0.9-2.4 +/- 1.0/control, P<0.05), but positive staining for GP IIb-IIIa complex did not alter significantly. (3) Ca(2+) influx induced by thrombin decreased (Th 0.3 U/ml: 345 +/- 29-298 +/- 24 nmol/l, P<0.05). The baseline [Ca(2+)](i), the release of Ca(2+) from internal stores induced by thrombin and the size of internal Ca(2+) stores did not alter. (4) platelet c-AMP increased (Th 0.3 U/ml: 66.4 +/- 9.4-82.6 +/- 13.0 fmol/l, P<0.05), but platelet nitrite/nitrate (NO(x)) or c-GMP did not alter significantly. CONCLUSIONS: These results suggest that modulation of platelet function by decreasing Ca influx and increased production of c-AMP may account in part for the cardiovascular benefit of ERT.

Awareness of the Japanese Society of Hypertension Guidelines for the Management of Hypertension and their use in clinical practices: 2009 survey results.

The objective of this study was to investigate physicians' awareness and use of the Japanese Society of Hypertension (JSH) Guidelines for the Management of Hypertension (JSH2004 and JSH2009), and determine what changes need to be implemented in the future. A questionnaire was used to survey physicians' awareness and their use of JSH2004 and JSH2009. Physicians attending educational seminars on hypertension that were held during the months after the publication of JSH2009 (January-April 2009) were asked to participate in the survey. Of the 5795 respondents, 88% were aware of the JSH2009 publication. Furthermore, physicians were also aware of JSH2004, with about 90% using JSH2004 in their practice. A hypertension blood pressure (BP) reference value of 140/90 mm Hg was used by 55% in office BP, whereas 31% used 135/85 mm Hg for home BP. Target BP levels used by physicians were 130/80 mm Hg for patients with diabetes or kidney disease (52%) and for elderly patients with diabetes or kidney disease (45%), whereas 140/90 mm Hg was used for elderly patients with low cardiovascular disease risk (44%) and for patients with chronic-phase stroke (27%). Answers to the questionnaire varied among physicians according to sex, age, workplace and specialty. The majority of the participating Japanese physicians were familiar with both JSH2004 and JSH2009, with many following the guidelines in their practice. However, some physicians use different reference values for hypertension and target BP levels. Physicians' adherence to and use of the guidelines should be regularly examined and promoted.

Effect of alcohol consumption on endothelial function in men with coronary artery disease.

An inverse relationship between moderate alcohol consumption and coronary artery disease (CAD) has been observed in several epidemiologic studies. Whether improvement of endothelial function is involved in this beneficial effect is unknown. We investigated endothelial function of the brachial artery in 108 men with CAD, 54 of whom consumed alcohol on at least 1 day per week. Brachial artery diameter responses to hyperemic flow (FMD) and to administration of nitroglycerin (NTG) spray were measured using high- resolution ultrasonography. Coronary risk factors and hyperuricemia were present more frequently among drinkers, who also had higher concentrations of triglyceride and apolipoproteins C2, C3, and E. FMD was greater in drinkers (P<0.0001), while NTG-induced dilation was not. Multiple regression analysis showed alcohol consumption to be one of the factors favorably influencing FMD. These findings suggest that alcohol consumption may improve endothelial function in men with CAD.

A frameshift mutation of beta subunit of epithelial sodium channel in a case of isolated Liddle syndrome.

BACKGROUND: Liddle syndrome is an autosomal dominant form of salt-sensitive hypertension caused by mutations in the epithelial sodium channel expressed in the distal nephron playing an essential role in Na absorption. All reported mutations in Liddle syndrome are either missense mutations or frameshift mutations destroying the PY motif closer to the C-terminus of the beta or gamma subunits causing the situation that the epithelial sodium channels are not degraded and sodium is pooled and thus hypertension and hypokalemia are caused. METHODS: We sequenced the C-terminus of the beta or gamma subunits of the epithelial sodium channel in a Japanese family of a patient clinically diagnosed as having Liddle syndrome. RESULTS: As a result, we found in the proband, a frameshift mutation of the beta subunit caused by a single cytosine insertion at the codon 595, introducing a new stop codon at 605 and deleting the last 34 amino acids from the normally encoded protein. CONCLUSION: This mutation is carried by neither parent (with paternity proven) and hence confirms this has occurred as a event within this family.

Tetrahydrobiopterin enhances forearm vascular response to acetylcholine in both normotensive and hypertensive individuals.

BACKGROUND: A deficiency of tetrahydrobiopterin (BH4), an essential cofactor for nitric oxide (NO) synthase, decreases NO synthesis and increases superoxide production. Supplementation of BH4 has been postulated to improve endothelial function in atherosclerotic patients. The purpose of this study was to determine whether BH4 restores endothelium-dependent vasodilation in patients with essential hypertension. METHODS: We evaluated the effects of BH4 on forearm vascular responses to acetylcholine (ACh), an endothelium-dependent vasodilator, and isosorbide dinitrate (ISDN), an endothelium-independent vasodilator, both in patients with essential hypertension and in age- and sex-matched normal control subjects. Forearm blood flow (FBF) was measured using strain gauge plethysmography. RESULTS: The response of FBF to ACh was less in hypertensive patients (n = 8) than in normal control subjects (n = 8). There was no significant difference in FBF response to ISDN in the two groups. During coinfusion of BH4 (500 mg/min), the FBF response to ACh in hypertensive patients increased significantly (14.8 +/- 4.6 to 25.6 +/- 7.3 mL/min/100 mL tissue, P < .05) to the level of normal control subjects. In the control subjects, also, BH4 augmented the FBF response to ACh (27.8 +/- 8.7 to 36.1 +/- 9.6 mL/min/100 mL tissue, P < .05). The increase in FBF after ISDN was not altered by BH4 in either group (each group, n = 6). CONCLUSION: Supplementation of BH4 augments endothelium-dependent vasodilation in both normotensive and hypertensive individuals.

A low-calorie diet improves endothelium-dependent vasodilation in obese patients with essential hypertension.

BACKGROUND: Both obesity and hypertension are associated with endothelial dysfunction. The purpose of this study was to investigate the effects of a low-calorie diet on endothelial function in obese patients with essential hypertension. METHODS: We measured forearm blood flow (FBF) during intra-arterial infusion of acetylcholine (ACh; 7.5, 15, 30 microg/min), an index of endothelium-dependent vasodilation, and isosorbide dinitrate (ISDN; 0.75, 1.5, 3.0 microg/min), an index of endothelium-independent vasodilation, in obese patients with essential hypertension before and after 2 weeks on a low-calorie diet (800 kcal/d). The study included 11 obese hypertensive Japanese patients (mean body mass index, 30.8 +/- 3.6 kg/m2). Fifteen healthy Japanese normotensive individuals were recruited as a control group. RESULTS: In obese patients with hypertension, the response of FBF to ACh was attenuated compared to healthy individuals (P < .001). Caloric restriction reduced body weight from 77.5 +/- 15.0 to 73.2 +/- 13.5 kg (P < .01), the mean blood pressure from 118.4 +/- 8.7 to 105.7 +/- 8.5 mm Hg (P < .01), fasting plasma insulin from 85.8 +/- 22.8 to 64.8 +/- 27.0 pmol/L (P < .05), serum total cholesterol from 5.30 +/- 0.76 to 4.67 +/- 0.58 mmol/L (P < .05), and low density lipoprotein cholesterol from 3.80 +/- 0.48 to 3.29 +/- 0.44 mmol/L (P < .05). Basal FBF was similar before and after weight reduction. Caloric restriction enhanced the response of FBF to ACh (P < .05), but did not alter the response to ISDN. The intra-arterial infusion of NG-monomethyl-L-arginine (8 micromol/min), a nitric oxide synthase inhibitor, decreased the enhanced ACh-induced blood flow response induced by caloric restriction. CONCLUSIONS: The present findings suggest that the caloric restriction improves endothelial-dependent vasodilation through an increased release of nitric oxide in obese hypertensive patients.

Leptin causes vasodilation in humans.

Leptin, a product of the ob gene, plays an important role in the regulation of body fat and has been suggested to cause vasodilation in rats. The purpose of this study was to evaluate whether leptin also has a vasodilating effect in humans. Using a strain-gauge plethysmography, we evaluated forearm blood flow (FBF) during intra-arterial infusion of leptin (1, 10 or 100 ng/kg/min for 5 min) in the absence and presence of the nitric oxide synthase inhibitor N(G)-monomethyl-L-arginine (L-NMMA; 8 micromol/min for 5 min) in ten healthy men (mean age, 23.0+/-1.2 years). Leptin infusion significantly increased the FBF (8.5+/-3.8, 20.3+/-7.0 and 17.7+/-5.4% at 1, 10 and 100 ng/kg/min of leptin, respectively; p<0.05) and the forearm vascular resistance (FVR; -6.9+/-3.1, -14.6+/-4.3 and -13.4+/-3.9% at 1, 10 and 100 ng/kg/min of leptin, respectively; p<0.05). No significant changes in blood pressure or heart rate were detected during infusion of leptin. The intra-arterial infusion of L-NMMA did not alter the FBF response (6.6+/-4.9, 22.1+/-7.5, 13.3+/-3.2% at 1, 10 and 100 ng/kg/min of leptin, respectively) or the FVR response (-4.3+/-4.6, -15.2+/-5.4, -11.1+/-2.5% at 1, 10 and 100 ng/kg/min of leptin, respectively) to leptin. These findings suggest that leptin per se directly causes vasodilation and that leptin-induced vasodilatation is nitric oxide-independent in healthy men.

Sweet elements of Siraitia grosvenori inhibit oxidative modification of low-density lipoprotein.

This study examined the ability of sweet elements extracted from Siraitia grosvenori (SG) to inhibit the oxidation of LDL. We monitored the formation of conjugated diene during copper-mediated LDL oxidation in the presence or absence of sweet elements of whole extract of SG (SG extract) or cucurbitane glycosides (CGs) purified from SG extract as sweet elements. CGs consist of Mogroside IV (Mog.IV), Mogroside V (Mog.V), 11-Oxo-mogroside V (11-Oxo-mog.V), and Siamenoside I (Sia.I). In addition, the effect of these elements on human umbilical vein endothelial cell (HUVEC)- mediated LDL oxidation was tested by measuring production of lipid peroxides. SG extract inhibited copper-mediated LDL oxidation in a dose-dependent fashion, but neither glucose nor erythritol suppressed the oxidation. Among CGs, 11-Oxo-mog.V significantly inhibited LDL oxidation, and prolongation of the lag time during LDL oxidation by 11-Oxo-mog.V was dose-dependent. The lag time (119.7 +/- 8.9 min) in the presence of 200 microM 11-Oxo-mog.V was significantly longer than that (76.8 +/- 5.5 min) of control (p < 0.01). In addition, SG extract and 11-Oxo-mog.V inhibited HUVEC-mediated LDL oxidation in a dose-dependent manner. These results demonstrate that SG extract can inhibit LDL oxidation and that 11-Oxo-mog.V, a sweet element of SG extract, provides the anti-oxidative property of SG which might reduce the atherogenic potential of LDL.

Myocardial bridging increases the risk of coronary spasm.

BACKGROUND: Myocardial bridging (MB) has been associated with cardiac events. Whether coronary spasm is one factor contributing to those events is unknown. HYPOTHESIS: This study investigated whether the likelihood of coronary spasm is increased in patients with MB. METHODS: A spasm-provocation test was performed by infusing acetylcholine into the left coronary artery in 114 Japanese patients with chest pain. The test result was defined as positive when the diameter of the coronary artery was reduced by > or = 50% and ST-segment changes were documented. Myocardial bridging was defined as a > 15% reduction in coronary arterial diameter during systole after intracoronary injection of nitroglycerin. RESULTS: Myocardial bridging was identified in 41 patients (36%) and was located in the mid-segment of the left anterior descending coronary artery (LAD) in all patients. Patients with MB experienced coronary spasm more frequently than patients without MB (MB+: 73%; MB-: 40%, p = 0.0006). Furthermore, among patients with a positive spasm-provocation test, coronary spasm occurred more frequently in the mid-segment of the LAD in patients with MB than in those without MB (MB+: 73%; MB-: 45%, p = 0.0259). Multivariate regression analysis demonstrated that MB was a predictor of coronary spasm (odds ratio: 3.478, p = 0.0088). CONCLUSIONS: These results suggest that MB increases the risk of coronary spasm and that coronary spasm may be the proximate etiology of cardiac events associated with MB.

Preconditioning effect during coronary angioplasty in patients with stable angina pectoris.

OBJECTIVE: To determine whether collateral recruitment is involved in the preconditioning effect on the electrocardiogram, chest symptoms, and lactate metabolism during coronary angioplasty in patients with stable angina pectoris. METHODS AND PATIENTS: Sixteen patients with stable angina pectoris underwent three consecutive 2-min balloon inflations 5-min apart. The greatest ST elevation (deltaSTmax), the sum of ST elevations in all leads (sum(ST)), and QT dispersion (QTd) were measured at the end of each balloon inflation. Chest pain score was evaluated on a scale ranging from no pain (0) to the most severe pain (10). Lactate extraction ratio (LER) was determined by simultaneous blood sampling from the aorta and the coronary sinus. Collateral flow index (CFI) was derived from simultaneous measurements of mean aortic pressure and coronary wedge pressure obtained from a pressure guidewire during balloon inflation. RESULTS: Significant decreases were noted in deltaSTmax (3.3+/-2.1 vs. 3.0+/-1.9 vs. 2.6+/-1.8 mm, p<0.01), sum(ST) (9.7+/-7.2 vs. 8.5+/-6.1 vs. 6.9+/-5.3 mm, p<0.01), QTd (55.3+/-13.8 vs. 46.9+/-9.0 vs. 42.5+/-10.0 ms, p<0.01), and chest pain score (4.3+/-3.1 vs. 2.8+/-2.6 vs. 1.4+/-1.5, p<0.01) during the three sequential balloon inflations. LER significantly increased (-55.5+/-47.8 vs. -36.7+/-34.3 vs. -19.6+/-26.2%, p<0.01), indicating decreased lactate production. No significant difference was observed in CFI (0.16+/-0.10 vs. 0.15+/-0.10 vs. 0.15+/-0.10). CONCLUSION: Repeated balloon inflations during coronary angioplasty elicited a preconditioning effect on ST-segment shift, QT dispersion, chest pain, and lactate production that does not involve collateral recruitment.