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PubMed2002

[Primary and secondary prevention of arteriosclerosis. Risk stratification of hypertension].

Hypertension is one of the important risk factors in the pathogenesis of arteriosclerosis. The differences between primary and secondary prevention in diagnosis and therapeutic strategies are reviewed from international studies. The optimal therapy for hypertension and risk stratification, including all other risk factors, will reduce the incidence and mortality of coronary heart disease and stroke.

Adolescent↗
PubMed2003

[Therapy and risk-stratification in hypertrophic cardiomyopathy--a current survey].

Hypertrophic cardiomyopathy (HCM) is a relatively common disease of the cardiac sarcomere with broad heterogeneity in terms of the disease-causing gene mutation, phenotypic expression, therapy and prognosis. Besides the standard drug treatment, there are several therapeutic options available for severe refractory symptomatic HCM with obstruction. Dual-chamber pacing and transcoronary ablation of septal hypertrophy (TASH) have recently emerged as alternatives to myectomy. However, myectomy remains the current gold standard of therapy for HCM until the promising initial follow-up data for TASH can be transferred into a long-term follow-up period, or prospective randomized comparative trials between these therapies are available. However, even now, TASH represents an important therapeutic alternative in patients with relevant co-morbidities and a high operative risk. Despite significant gradient reduction and amelioration of clinical symptoms, none of these treatment strategies has a proven influence on the natural history of HCM. Hence, regarding the long-term prognosis of the disease, risk stratification of sudden cardiac death using non-invasive risk assessment has become of paramount importance, while genotyping might become the determinant and stratifying marker in the near future. At present, according to secondary prevention, treatment with an implanted cardioverter-defibrillator +/- amiodarone therapy is mandatory, while according to primary prevention treatment should particularly depend on the individual risk profile.

Cardiomyopathy, Hypertrophic↗
PubMed1997

[Acute coronary vessel occlusion after PTCA--possibility of risk stratification using quantitative coronary angiography, clinical determinants and laboratory chemistry parameters].

Abrupt vessel closure of the dilated vessel continues to represent a significant limitation of coronary angioplasty. Despite increasing operator experience and improved technology, abrupt vessel closure continues to represent the most important complication of balloon angioplasty. Intracoronary stent implantation and pharmaceutical blockade of the GPIIb/IIIa receptor serve as effective tools in the prevention of abrupt vessel closure without completely resolving this problem. About 50% of patients presenting with abrupt vessel closure exhibit additional complications including myocardial infarction, necessity of CABG or death occurring in up to 10% of acute occlusions. The purpose of this study is to evaluate if quantitative coronary angiography and assessment of clinical and laboratory data allows risk stratification concerning the probability of abrupt vessel closure. PTCA in the setting of acute coronary syndrome is associated with a markedly increased risk of abrupt vessel closure, indicating that different risk factors may contribute to the development of abrupt vessel closure in patients presenting with stable angina or acute coronary insufficiency syndromes. 798 uncomplicated PTCA procedures for stable angina pectoris were compared with 68 interventions that were complicated by abrupt vessel closure. Furthermore, 133 successful angioplasty procedures for acute coronary syndromes defined as acute myocardial infarction or unstable angina pectoris were matched with 31 procedures for acute coronary syndromes with consecutive abrupt vessel closure. In patients presenting with stable angina pectoris stenosis length, stenosis eccentricity, minimal lumen diameter, degree of the stenosis after angioplasty, female gender, and fibrinogen could be defined as independent predictors of abrupt vessel closure. In acute coronary syndromes, only minimal lumen diameter, recanalization of completely occluded coronary arteries and fibrinogen were associated with an increased risk of abrupt vessel closure.

Aged↗
PubMed2000

[Risk stratification for sudden cardiac death in post-infarct patients and in patients with dilated cardiomyopathy].

In patients with structural heart disease and sustained symptomatic ventricular tachycardia or ventricular fibrillation without reversible cause, the implantable cardioverter-defibrillator has become the therapy of first choice. Besides the "MADIT indication", however, arrhythmia risk stratification with regard to prophylactic ICD implantation is an unsolved problem. This overview summarizes the currently very limited clinical value of potential risk predictors for sudden cardiac death in postinfarct patients and in patients with dilated cardiomyopathy.

Cardiomyopathy, Dilated↗
PubMed2003

Role of nonsustained ventricular tachycardia and programmed ventricular stimulation for risk stratification in patients with idiopathic dilated cardiomyopathy.

BACKGROUND: The prognostic role of asymptomatic nonsustained ventricular tachycardia (NSVT) and programmed ventricular stimulation (PVS) in patients with idiopathic dilated cardiomyopathy (IDC) remains controversial. METHODS: The prognostic significance of ventricular arrhythmias, ejection fraction, NYHA class, atrial fibrillation and age for overall and sudden death mortality was prospectively studied in 157 patients with IDC (group 1) free of documented sustained ventricular arrhythmia and syncope. In 99 patients with asymptomatic NSVT (group 2), PVS with 2 - 3 extrastimuli was performed. Non-inducible patients were discharged without specific antiarrhythmic therapy, whereas those with inducible monomorphic ventricular tachycardia were implanted with an ICD. RESULTS: In group 1, 48% of patients had NSVT. Overall and sudden death mortality were significantly higher in patients with NSVT (34.2 vs. 9.8%, p = 0.0001 and 15.8 vs. 3.7%, p = 0.0037; follow-up 22 +/- 14 months). Multivariate analysis revealed that NSVT independently predicts both overall and sudden death mortality (p = 0.0021 and.0221, respectively; adjusted for EF, NYHA class and age). In group 2, inducibility of sustained ventricular tachyarrhythmia was 7%, but sustained monomorphic VT occurred in 3% only. Two of 7 inducible patients experienced arrhythmic events during a follow-up of 25 +/- 21 months (positive predictive value 29%). Overall and sudden death mortality were 29% and 0% in the inducible group vs. 17 and 4% in the non-inducible group. Both overall and sudden death mortality were significantly lower in non-inducible patients from group 2 as compared to patients from group 1 with NSVT (p = 0.0043 and 0.0048), most likely due to a more common use of betablockers and a higher EF in the former group (p < 0.001, respectively). CONCLUSIONS: In patients with IDC, NSVT independently predicts both overall and sudden death mortality. Due to a low inducibility rate and a poor positive predictive value, PVS seems inappropriate for further arrhythmia risk assessment. However, in spite of documented NSVT, the incidence of SCD in patients on optimized medical treatment including betablockers seems to be very low, questioning the need for specific arrhythmia risk stratification.

Adult↗
PubMed2003

Longitudinal stratification of gait economy in young boys and girls: the locomotion energy and growth study.

The purpose of this study was to determine if the relative ordering of locomotor oxygen consumption ( VO(2)) values remains stable as healthy children age. Beginning at age 6 and ending at age 10, VO(2) during level treadmill walking and running was quantified in 15 boys and 18 girls who were tested on an annual basis. Following 30 min of treadmill accommodation to each exercise mode, subjects walked and ran for 5 min at 1.34 m s(-1) and 2.23 m s(-1), respectively. During the last 2 min of each 5-min stage, expired gas samples were collected and analyzed to quantify VO(2). For both walking (W) and running (R), 27% of subjects showed an average yearly change in VO(2) rank order of </=2 positions, 64% (W) and 61% (R) displayed a mean annual shift in VO(2) rank order of </=4 positions, and 85% exhibited a mean yearly fluctuation in W and R VO(2) rank order of </=6 positions. Reliability analysis of VO(2) responses across the 5-year testing period also yielded high coefficient alpha values for walking ( R=0.91) and running ( R=0.94). These results suggest that the relative ordering of individual gait VO(2) values remains quite stable in young children, indicating a physiological stratification that is fairly resistant to change during a period featuring increases in physical growth and varied exposure to different types of physical activity.

Child↗
PubMed2005

Gene expression and immunolocalisation of a calcium-activated chloride channel during the stratification of cultivated and developing corneal epithelium.

The spatial and temporal localisation of a calcium-activated chloride channel (CLCA) and its mRNA was investigated, during the in vivo and in vitro development of stratified epithelia, by fluorescence immunohistochemistry and quantitative polymerase chain reaction in embryonic chicken corneas and the expansion of excised human corneal stem cells on amniotic membrane. Single-layered human epithelial cultures on amniotic membrane and early day embryonic chicken corneas expressed relatively little human CLCA2 or its chicken homologue. However, as the epithelium in both models matured and the number of cell-layers increased, the gene expression level and protein staining intensity increased, primarily within the basal cells of both the cultured and embryonic tissues. These results demonstrate that human CLCA2 protein and mRNA expression are elevated during epithelial stratification, suggesting that this protein plays a role in the growth of multi-layered corneal epithelia during both natural development and tissue cultivation.

Animals↗
PubMed2000

Preoperative abdominal ultrasound may be misleading in risk stratification for presence of common bile duct abnormalities.

BACKGROUND: Following the advent of laparoscopic cholecystectomy (LC), the preoperative predictors of common bile duct (CBD) abnormalities became more important in perioperative decision making. Preoperative transabdominal ultrasound (US) is used to assess the preoperative risks associated with CBD abnormalities. This study attempts to determine the sensitivity and specificity of US in determining CBD abnormalities in patients prior to LC. METHODS: US measurements of the CBD diameter and presence of stones were ascertained from radiology reports in 100 patients who had LC with a routine intraoperative cholangiogram (IOC). The same information was obtained from the patients' IOC. A supraduodenal CBD diameter of >8 mm was considered dilated. RESULTS: US demonstrated a sensitivity of 25% and a specificity of 70% for the detection of CBD dilatation compared to IOC. The sensitivity of US for predicting CBD dilatation was 55% when the IOC-derived diameter was >10 mm and 100% when it was >15 mm. The overall sensitivity of US for detection of stones was 10%; it improved to 17% in patients with a dilated CBD on US. CONCLUSIONS: Preoperative ultrasound is neither sensitive nor specific for detecting CBD dilatation or presence of stones. A negative preoperative US report may be misleading in risk stratification for the presence of these CBD abnormalities. In order to avoid missing any CBD pathology, we recommend the routine use of intraoperative cholangiography.

Cholangiography↗
PubMed2006

Stand structure and woody species diversity in relation to stand stratification in a subtropical evergreen broadleaf forest, Okinawa Island.

Stand structure and woody species diversity in a subtropical evergreen broadleaf forest grown in a silicate habitat, Okinawa Island, have been investigated on the basis of stand stratification. The forest stand consisted of four layers. The floristic composition of the top and the lower three layers was only slightly similar, although approximately one-third of the species were common to them. Mean tree weight decreased from the top toward the bottom layer whereas tree density increased from the top downward. This trend resembled the mean weight-density trajectory of self-thinning plant populations. The relationship between mean tree height and tree density for the upper two layers supported Yamakura's quasi -1/2 power law of tree height. The values of the Shannon-Wiener index, H', and the equitability index, J', tended to increase from the top layer downward except for the bottom layer. The values of H' and J' were, respectively, 4.83 bit and 0.82 for trees taller than 0.10 m. The lower layers contained many species of smaller height. High species diversity of the forest depended on small trees in the lower layers. Conservation of small trees in the lower layers, especially the bottom layer, is indispensable for sound maintenance of Okinawan evergreen broadleaf forests.

Biodiversity↗
PubMed2006

Temperature measurement and stratification in facultative waste stabilisation ponds in the UK climate.

Temperature measurements were taken at three pilot-scale facultative ponds located at Esholt wastewater treatment works in West Yorkshire, UK over two one-year periods. The measurements were taken at different depths using a technology called Thermochron iButton. The iButton readings were compared with temperature measurements taken by a YSI sonde probe and maximum/minimum thermometers: they were found to be within 1 .C. In the temperature range 3.18 .C the mean weekly and monthly air temperatures were found to be good predictors for the mean weekly and monthly pond water-column temperatures. The level of stratification in the ponds under UK climatic conditions was assessed; the data revealed that the ponds remained thermally stratified for significant periods during the year despite their shallow depth.

Climate↗
PubMed2004

Coronary calcium screening and coronary risk stratification.

Current vital statistics clearly indicate a continuing epidemic of cardiovascular disease in the Western hemisphere and strongly suggest that the most desirable approach to this ailment is prevention rather than delayed treatment. Over 7 million people in the United States suffer from coronary artery disease and more than 500,000 die from its complications annually. In the majority of cases, the event announcing the presence of atherosclerosis is either sudden death or a disabling myocardial infarction or stroke. Though recent trials indicate a need for treatment of very large segments of the population, a review of current clinical practices indicates that the preventive attitude of the majority of physicians is not sufficiently developed and remains limited in most training programs. Additionally, although traditional risk factors are very helpful in predicting the development of cardiovascular disease, many individuals suffer events in the absence of established risk factors for atherosclerosis. To meet the challenge of coronary artery disease, several tools have been developed to identify atherosclerotic disease in its preclinical stages, with the hope of modifying its natural history. In this article, we review the current literature on utilization of electron beam tomography for detection of coronary artery calcification as a tool to conduct risk stratification for coronary artery disease events in the general population.

Animals↗
PubMed2004

Risk stratification and epidemiology of sudden death.

Recent data from the Centers for Disease Control and Prevention show that sudden cardiac death accounts for approximately 400,000 deaths annually in this country. The survival rate for these patients is dismal. Because of the low probability of survival from a cardiac arrest, there has been an increasing focus on primary prevention. The implantable cardioverter defibrillator (ICD) is a highly effective treatment to abort potentially fatal arrhythmic episodes. Thus, various trials have been conducted to determine methods to best identify patients at high risk for sudden arrhythmic death. This review focuses on the epidemiology of sudden cardiac death and risk stratification approaches that have been tested to determine whether they can identify populations likely to benefit from an ICD.

Clinical Trials as Topic↗
PubMed2000

Gender differences in socioeconomic returns to family migration in Malaysia: the role of family decision making versus labor market stratification.

In this article the author examines gender differences in the effect of family migration on socioeconomic attainment in Malaysia. The analysis discerns the relative importance of gender roles in household migration decisions, compared to gender stratification in the labor market. The Malaysian economy has undergone rapid industrialization and great structural changes which have opened up new economic opportunities, particularly for women. Despite the somewhat advantaged position of women compared to men in the Malaysian labor market, the author finds that men experience much greater socioeconomic gains than women from family migration. Hence indicating that family migration decisions in Malaysia, rather than optimizing family gains, compensate for the gender effect in the labor market. However, the gains of Malaysian men are more assured when they move alone. Data for the study come from the second round of the Malaysian Family Life Survey.

Asia↗
PubMed1985

The use of rest and exercise radionuclide ventriculography in risk stratification in patients with suspected coronary artery disease.

The study examined the value of rest and exercise radionuclide ventriculography in risk stratification in patients with suspected coronary artery disease. There were 604 patients, 474 men and 130 women, aged 55 +/- 11 years (mean +/- standard deviation). At a follow-up of 18 +/- 10 months, there were 43 hard cardiac events: 27 patients died of cardiac causes and 16 had nonfatal acute myocardial infarctions. Univariate and multivariate survival analysis of the 10 most important clinical and exercise variables identified the exercise left ventricular ejection fraction as the most important predictor of death and total cardiac events (chi 2 = 18.1 and 29.6, respectively). The exercise heart rate was a significant, independent, but much weaker predictor of cardiac death and total events (chi 2 = 8.4 and 3.9, respectively), while exercise tolerance was a significant independent predictor of cardiac death only (chi 2 = 6.4). Actuarial life table analysis showed that the risk for future cardiac events increased in stepwise fashion as the exercise ejection fraction decreased. Thus, the exercise left ventricular ejection fraction is a useful prognosticator in patients with suspected coronary artery disease. This finding has important implications in patient management.

Actuarial Analysis↗
PubMed1991

Risk stratification in survivors of acute myocardial infarction: routine cardiac catheterization and angiography is a reasonable approach in most patients.

Noninvasive risk assessment in survivors of AMI can effectively subdivide patients into groups with differing risk profiles after hospital discharge, but some patients at risk for late death or recurrent AMI may be incorrectly identified; data from cardiac catheterization and angiography provide complementary and generally more powerful prognostic information. Many patients may derive particular benefit from early cardiac catheterization and angiography, including: (1) patients with AMI complicated by recurrent myocardial ischemia, congestive heart failure, and/or complex ventricular arrhythmias; (2) patients with abnormal or inconclusive results of noninvasive testing or those patients unable to perform an exercise test; (3) patients with abnormal left ventricular global systolic function and those with increased left ventricular end-systolic volume; (4) "young" patients (younger than 50 years of age?); (5) older patients (older than 65 to 70 years of age?); (6) patients with non-Q wave AMI; and (7) patients who are receiving thrombolytic therapy. Performance of early cardiac catheterization and angiography in virtually all survivors of AMI, with selective use of appropriate noninvasive tests, may provide a more efficacious means of risk assessment after AMI; if all tests are performed judiciously, the cost of such an approach need not be excessive. A combination of invasive and selected noninvasive tests probably provides optimal information. The risks to the routine performance of diagnostic cardiac catheterization and angiography in all survivors of AMI are: (1) adequate care and attention may not be paid to proper performance of the procedure(s) and to detailed and proper analyses of the data; (2) the need for additional noninvasive testing in selected patients may be ignored; and most importantly, (3) premature or unnecessary revascularization procedures may be performed subsequently. For optimal patient care, the clinician must obtain all necessary data, avoid unnecessary and repetitive tests, know the accuracy of individual tests at his or her own facility, interpret all data in proper context, and then counsel patients objectively about available management strategies. With this approach, all patients who might appropriately benefit from coronary artery revascularization will be correctly identified, and patients who are truly at very low risk (minimal residual coronary artery disease and preserved left ventricular function particularly if associated with a patent infarct-related artery) may be similarly identified and managed appropriately with elimination of unnecessary additional testing and pharmacologic therapy. Finally, whatever approach to risk stratification one chooses for an individual patient, the importance of and the need to correct and/or ameliorate risk factors for coronary artery disease must be recognized and undertaken.

Age Factors↗
PubMed1993

Prediction of sudden cardiac arrest: risk stratification by anatomic substrate.

The prognostic importance of coronary artery anatomy to specific outcomes including ventricular tachycardia/fibrillation was evaluated in 372 consecutive patients undergoing cardiac catheterization at University Hospital at Stony Brook between 1981 and 1984. The hypothesis that proximal left anterior descending artery narrowing before the first septal perforator had a specific relationship to survival was again tested in this cohort. The population was prospectively followed for 8 years, with all clinical management decisions made independently by the patient's primary or referring physician. Multivariate statistical and life table analyses were performed after comprehensive follow-up. Significant narrowing in the proximal left anterior descending artery was associated with an increased risk of sudden cardiac death (p = 0.0002). Abnormalities of contractility in the diaphragmatic segment of the left ventricle in addition to an elevation of the left ventricular end-diastolic pressure and the presence of congestive heart failure (p < 0.05) were other contributory variables. Outcome in patients with proximal left anterior descending coronary artery disease who underwent aortocoronary artery bypass to the artery demonstrated improved survival (p < 0.05). Risk stratification of patients at high risk for sudden cardiac death is possible and may allow identification for an aggressive approach or interventional trials.

Adult↗
PubMed1983

Stepwise risk stratification soon after acute myocardial infarction.

A stepwise rise stratification procedure sequentially combining historical and clinical characteristics and treadmill exercise test results was applied to 702 consecutive men aged less than or equal to 70 years who were alive 21 days after acute myocardial infarction (MI). Historical characteristics alone (prior MI and prior angina or recurrence of pain in the coronary care unit) identified 10% of patients with the highest rate of reinfarction and death within 6 months (18%). Clinical contraindications to exercise testing identified another 40% of patients with an intermediate rate of cardiac events (6.4%). In the 50% of patients who underwent treadmill testing 3 weeks after MI, the rate of cardiac events within 6 months was 4.4%: 3.9% in patients with a negative test and 9.7% in patients with a positive test (ischemic ST-segment depression greater than or equal to 0.2 mV and a peak heart rate less than or equal to 135 beats/min). Patients with negative treadmill tests, who comprised 46% of patients less than or equal to 70 years and 53% of patients less than or equal to 60 years, had a cardiac death rate of less than 2% in the 6 months after MI. The stepwise classification procedure correctly classified 72% of patients with hard medical events within 6 months. Thus, most patients who experience subsequent cardiac events are correctly classified on the basis of historical and clinical risk characteristics. In patients without these risk characteristics, early treadmill testing is useful for further discriminating high-risk from very low risk patients.

Aged↗
PubMed1985

Cardiac arrest and sudden death in patients treated with amiodarone for sustained ventricular tachycardia or ventricular fibrillation: risk stratification based on clinical variables.

Multivariate analysis of 11 clinical variables was performed in 104 patients with sustained, symptomatic ventricular tachycardia (VT) or ventricular fibrillation treated with amiodarone to determine variables predictive of subsequent cardiac arrest or sudden death. Twenty-five patients (24%) had fatal or nonfatal cardiac arrest after 7.3 +/- 6.2 months (mean +/- standard deviation) of therapy. Multivariate analysis identified an ejection fraction of less than 0.40, syncope or cardiac arrest before amiodarone therapy, and VT (3 or more consecutive ventricular premature complexes) during predischarge ambulatory electrocardiographic monitoring as variables associated with a high risk of subsequent fatal or nonfatal cardiac arrest (p less than 0.03). Patients who had these 3 clinical variables had a much higher predicted incidence of cardiac arrest at 6 months (62%) and 12 months (76%) than did patients with an ejection fraction greater than 0.40, without syncope or cardiac arrest before amiodarone therapy, and without VT during predischarge ambulatory electrocardiographic monitoring (2% and 5%, respectively) (p less than 0.02). Risk stratification using clinical variables can predict which patients are at high risk of recurrent cardiac arrest or sudden death during amiodarone therapy.

Aged↗