Exploiting Distributed, Heterogeneous and Sensitive Data Stocks while Maintaining the Owner’s Data Sovereignty

Background: To achieve statistical significance in medical research, biological or data samples from several bio- or databanks often need to be complemented by those of other institutions. For that purpose, IT-based search services have been established to locate datasets matching a given set of criteria in databases distributed across several institutions. However, previous approaches require data owners to disclose information about their samples, raising a barrier for their participation in the network.

Objective: To devise a method to search distributed databases for datasets matching a given set of criteria while fully maintaining their owner’s data sovereignty.

Methods: As a modification to traditional federated search services, we propose the decentral search, which allows the data owner a high degree of control. Relevant data are loaded into local bridgeheads, each under their owner’s sovereignty. Researchers can formulate criteria sets along with a project proposal using a central search broker, which then notifies the bridgeheads. The criteria are, however, treated as an inquiry rather than a query: Instead of responding with results, bridgeheads notify their owner and wait for his/her decision regarding whether and what to answer based on the criteria set, the matching datasets and the specific project proposal. Without the owner’s explicit consent, no data leaves his/ her institution.

Results: The decentral search has been deployed in one of the six German Centers for Health Research, comprised of eleven university hospitals. In the process, compliance with German data protection regulations has been confirmed. The decentral search also marks the centerpiece of an open source registry software toolbox aiming to build a national registry of rare diseases in Germany.

Conclusions: While the sacrifice of real-time answers impairs some use-cases, it leads to several beneficial side effects: improved data protection due to data parsimony, tolerance for incomplete data schema mappings and flexibility with regard to patient consent. Most importantly, as no datasets ever leave their institution, owners can reject projects without facing potential peer pressure. By its lower barrier for participation, a decentral search service is likely to attract a larger number of partners and to bring a researcher into contact with the right potential partners.

Assessment of trastuzumab-related cardiac dysfunction in the Herceptin Adjuvant (HERA) Trial with 3.6 years median follow- up

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Background: The Herceptin Adjuvant (HERA) Trial is a three-group randomized trial that compared 1 year or 2 years trastuzumab with observation. We investigated cardiac dysfunction in HERA patients randomized to observation or 1 year trastuzumab and report results at a median follow-up of 3.6 years. Methods: Only patients who after completion of (neo)adjuvant chemotherapy with or without radiotherapy had normal left ventricular ejection fraction (LVEF > 55%) were eligible. Cardiac function was monitored throughout the trial. A repeat LVEF assessment was required in case of cardiac dysfunction. Results: There were 1,698 patients randomized to observation and 1,703 randomized to 1 year trastuzumab. The incidence of discontinuation of trastuzumab due to cardiac disorders was low (5.1%). The incidence of cardiac endpoints was low (severe CHF 0.77% in the trastuzumab group). The incidence of cardiac endpoints was higher in the trastuzumab group compared to observation (severe CHF 0.77% vs 0.00%; confirmed significant LVEF drops 3.57% vs 0.64%). In the trastuzumab group, there were no occurrences of severe CHF after the end of the scheduled treatment period of 1 year. Among the patients in the trastuzumab group with confirmed significant LVEF drop, the first occurrence was within the scheduled treatment period of 1 year for 55 out of 60 patients (91.7%). In the trastuzumab group, 59 of 73 patients (80.8%) with a cardiac endpoint reached acute recovery and of these 59 patients 52 (88.1%) were consider to have a favourable long term outcome. Conclusions: The incidence of cardiac endpoints remains low even with longer term follow-up. The cumulative incidence of any type of cardiac endpoint increases during the scheduled treatment period of 1 year, but appears to remain approximately constant after the scheduled treatment period of 1 year is completed.

[Table: see text]

Cardiovascular phenotypes and functional parameters in the general population--results of the MONICA/KORA studies

The MONICA/KORA surveys are characterized by a careful and broad investigation of multiple cardiovascular phenotypes. Particularly, repeated blinded measurements of blood pressure, comprehensive echocardiographic and electrocardiographic evaluations as well as differentiation between fat and fat-free body mass have led to manifold innovative observations. Specifically, genetic and serological markers of the renin angiotensin system could be associated with high blood pressure and left ventricular hypertrophy. The same applies to the importance of parameters of body composition as obesity and muscular mass. Moreover, the prevalence of heart failure in the general population could be determined for the first time in Germany. Additionally, the prevalence of left ventricular systolic and diastolic dysfunction could be obtained in the region of the survey, exemplarily for the Federal Republic of Germany. Finally, the surveys of the population random sample were used to define normal serum levels of natriuretic peptides. In summary, the evaluation of cardiovascular phenotypes in the MONICA/KORA surveys resulted in a -- in the European region unique -- documentation of cardiovascular functional parameters in the general population. Moreover, multiple epidemiological observations as to pathophysiologically relevant topics of heart and vascular diseases could be studied in extraordinary details.

Verteilung, Determinanten und Referenzwerte linksventrikulärer Parameter in der Allgemeinbevölkerung - Resultate der MONICA/KORA-Echokardiographiestudien

For successful fighting against the burden of cardiovascular disease in the community a comprehensive knowledge about the prevalence and the impact of underlying risk factors is important. The present paper summarises some studies undertaken on more than 2000 persons from the MONICA/KORA-studies (parts of S1 and S3) where left ventricular mass (LVM) and other left ventricular parameters were determined by echocardiography. We especially investigated the associations of LVM with blood pressure and obesity. A special focus was on sex-specific factors in the determination of LVM and the influence of different indices of body size when normalising LVM. It could be shown that hypertension and obesity are major determinants of LV hypertrophy. Especially women with both hypertension and obesity on showed a high prevalence of concentric hypertrophy, significantly more than men. We also showed that the prevalence of LV hypertrophy in a representative sample of the general population (25 to 74 years) is 17.5 % for men, and 18.5 % for women. This underscores the need for primary and secondary prevention regarding the development of LV hypertrophy. Finally, our data in a selected group of normal subjects (reference sample) may be used for the development of reference values for left ventricular parameters in the general German population.

Anthracycline and trastuzumab in breast cancer treatment

This study was designed to evaluate the cardiac safety of the combined treatment of HER2-positive metastatic breast cancer patients with trastuzumab (Herceptin) plus epirubicin and cyclophosphamide (EC) in comparison with EC alone in HER2-negative metastatic breast cancer patients. Patients included those with metastatic breast cancer without any prior anti-HER2 treatment, anthracycline therapy, or any other chemotherapy for metastatic disease. This was a nonrandomized, prospective, dose-escalating, multicenter, open-label, phase I study in Germany. A control group of 23 patients received EC 90/600 mg/m2 3-weekly for six cycles (EC90 alone). A total of 26 HER2-positive patients were treated with trastuzumab, or H (2 mg/kg weekly after an initial loading dose of 4 mg/kg), and EC 60/600 mg/m2 3-weekly for six cycles (EC60+H); another 25 HER2-positive patients received H and EC 90/600 mg/m2 3-weekly for six cycles. Asymptomatic reductions in left ventricular ejection fraction (LVEF) of more than 10% points were detected in 12 patients (48%) treated with EC60+H and in 14 patients (56%) treated with EC90+H vs 6 patients (26%) in the EC90 alone cohort. LVEF decreases to <50% occurred in one patient in the EC60+H cohort and in two patients in the EC90+H cohort during the H monotherapy. No cardiac event occurred in the cohort with EC90 alone. The overall response rates for EC60+H and EC90+H were >60%, vs 26% for EC90 alone. The interim results of this study approve the cardiac safety of the combination of H with EC, with low risk of cardiac toxicity. The combination regimen revealed promising efficacy.

Cardiac safety of trastuzumab in combination with epirubicin and cyclophosphamide in women with metastatic breast cancer

This prospective, parallel-group, dose-escalation study evaluated the cardiac safety of trastuzumab (Herceptin) plus epirubicin/cyclophosphamide (EC) in women with human epidermal growth factor receptor-2 (HER2)-positive metastatic breast cancer (MBC) and determined an epirubicin dose for further evaluation. HER2-positive patients received standard-dose trastuzumab plus epirubicin (60 or 90 mg/m(2))/cyclophosphamide (600 mg/m(2)) 3-weekly (EC60+H, n=26; EC90+H, n=25), for four to six cycles; 23 HER2-negative patients received EC alone (90/600 mg/m(2)) 3-weekly for six cycles (EC90). All patients underwent thorough cardiac evaluation. Two EC90+H-treated patients experienced symptomatic congestive heart failure 4.5 and 6 months after the end of chemotherapy. One EC60+H-treated patient experienced an asymptomatic decrease in left ventricular ejection fraction (LVEF) to <50% 6 months after the end of chemotherapy. No such events occurred in control patients. Asymptomatic LVEF decreases of >10% points were detected in 12 (48%), 14 (56%) and 5 (24%) patients treated with EC60+H, EC90+H, and EC90. Objective response rates with EC60+H and EC90+H were >60%, and 26% for EC90 alone. These results indicate that trastuzumab may be combined with EC with manageable cardiotoxicity and promising efficacy.

[Epidemiology of left ventricular systolic dysfunction in the general population of Germany: results of an echocardiographic study of a large population-based sample]

The prevalence of left ventricular systolic dysfunction (LVSD) in the general population is poorly defined. Specifically, the number of asymptomatic individuals with LVSD and, thus, the most appropriate strategy to identify and treat such subjects is still unknown. Therefore, the aim of this study was to document LV dysfunction in a middle-aged (25 to 75 years, mean 51.8+/-13.8) population - based sample in Germany (MONICA Augsburg, n=1678; echocardiography technically adequate n=1418) by M-mode and 2D-echocardiography and to analyze the importance of predisposing contributors. The overall prevalence of an ejection fraction (EF) less than 48% (mean minus 2 SD=LVSD) was 2.3% (n=33), with a slightly higher rate in men than in women (2.8% vs 1.9%, n.s.). LVSD rate increased with age: from 1.5% in individuals younger than 40 years to 4.0% among those older than 60 years of age (p<0.05). Of 33 participants with reduced left ventricular systolic function, 20 presented with at least one cardiovascular disease. The most frequent diagnoses were arterial hypertension, obesity and coronary heart disease. Only 13 subjects (0.9%) of the study population were asymptomatic without a history of cardiovascular disease. Furthermore, only 6 subjects (0.4%, 4 male) in this population presented with a moderate impairment of LV function (EF of 30 to 40%) and only 1 subject (0.07%, male) had severe LVSD (EF less than 30%). Almost all subjects with an EF less than 40% (6 of 7 individuals) had a known history of cardiovascular disease. In conclusion, LVSD is a relatively common finding in the general population. However, severe LVSD is rare in subjects without any concomitant cardiovascular disease. Thus, echocardiographic screening cannot be recommended in the unselected, middle-aged population to identify such patients.

Prevalence of left ventricular diastolic dysfunction in the community. Results from a Doppler echocardiographic-based survey of a population sample

AIMS

The prevalence of left ventricular diastolic abnormalities in the general population is largely unclear. Thus, the aim of this study was, firstly, to identify abnormal diastolic function by echocardiography in an age-stratified population-based European sample (MONICA Augsburg, n=1274, 25 to 75 years, mean 51+/-14) and, secondly, to analyse clinical and anthropometric parameters associated with diastolic abnormalities.

METHODS AND RESULTS

The overall prevalence of diastolic abnormalities, as defined by the European Study Group on Diastolic Heart Failure (i.e. age dependent isovolumic relaxation time (92-105 ms) and early (E-wave) and late (A-wave) left ventricular filling (E/A-ratio, 1-0.5)) was 11.1%. When only subjects treated with diuretics or with left atrial enlargement were considered (suggesting diastolic dysfunction) the prevalence was 3.1%. The prevalence of diastolic abnormalities varied according to age: from 2.8% in individuals aged 25-35 years to 15.8% among those older than 65 years (P<0.01). Significantly higher rates of diastolic abnormalities were observed in men as compared to women (13.8% vs 8.6%, P<0.01). Independent predictors of diastolic abnormalities were arterial hypertension, evidence of left ventricular (LV) hypertrophy, and coronary artery disease. Interestingly, in the absence of these predisposing conditions, diastolic abnormalities (4.3%) or diastolic dysfunction (1.1%) were rare, even in subjects older than 50 years of age (4.6%) and (1.2%), respectively. In addition to these factors, diastolic dysfunction was related to high body mass index, high body fat mass, and diabetes mellitus.

CONCLUSION

The prevalences of diastolic abnormalities and diastolic dysfunction are higher than that of systolic dysfunction and are increased (despite age-dependent diagnostic criteria) in the elderly. However, in the absence of risk factors for diastolic abnormalities or diastolic dysfunction, namely LV hypertrophy, arterial hypertension, coronary artery disease, obesity and diabetes the condition is rare even in elderly subjects. These data allow speculation on whether diastolic heart failure may be prevented by improved implementation of measures directed against predisposing conditions.

[Ultrasonography of the inferior vena cava (IVC) in the diagnosis and monitoring of therapy in patients with chronic congestive heart failure]

OBJECTIVE

This prospective clinical study investigated whether the relatively simple and cost-effective ultrasonography of the inferior vena cava (IVC) represents a valid clinical tool to assess the effectiveness of diuretic therapy in patients with chronic congestive heart failure (CHF).

METHODS

Measurement of the resting and inspiratory diameter of the VCI repeatedly during diuretic therapy in 23 consecutive patients (11 women, 70 +/- 10 years) with CHF and comparing the results to the daily measured body weight and serum creatinine in these patients. Results were compared with the IVC diameter obtained in 33 healthy controls (16 women, 42 +/- 15 years). In addition, the IVC collapse index was calculated to assess inspiratory movements of the IVC in patients on day 1 and 10 of therapy.

RESULTS

The IVC diameter at rest was 2.4 +/- 0.6 cm and decreased to 2.0 +/- 0.7 cm at inspiration, which was significantly greater than in healthy controls (1.4 +/- 0.4 cm at rest and 1.05 +/- 0.5 cm at inspiration; p = 0.008 and p = 0.01, respectively). The IVC diameter decreased continuously and significantly (p < 0.003) from day 1 to day 10 during diuretic therapy without a concomitant rise in serum creatinine. At beginning of therapy, the collapse-index of the IVC was significantly greater in patients than in controls. However, after 10 days of therapy this index reached similar values to those observed in controls.

CONCLUSION

Ultrasonographic measurements of IVC diameter and inspiratory movements are a quantifiable and reliable approach to assess the hypervolemia associated with CHF. Normalization of inspiratory IVC collapse movement correlates with successful diuretic therapy and can be reliably used for bedside assessment and monitoring treatment in CHF patients.

Indexation of left ventricular mass in adults with a novel approximation for fat-free mass

BACKGROUND

Indexation to fat-free mass (FFM) seems to be the best option for adjusting left ventricular (LV) mass. However, measurements of FFM are frequently not available.

OBJECTIVES

To define the relation of FFM with commonly available anthropometric measures in order to derive an approximation formula of FFM that can be used for valid indexation of LV mass.

SUBJECTS AND METHODS

A total of 1,371 subjects from a community survey were examined by echocardiography to measure LV mass and by bioelectrical impedance analyses (BIA) for the determination of FFM. An approximation of FFM was generated in a healthy subgroup of 213 men and 291 women by non-linear regression techniques.

RESULTS

Compared with body height, height2.0, height2.7, (the superscripts following weight and height are raised powers used as a more appropriate method for indexing LV mass) or body surface area, FFM measured by BIA in the healthy subgroups was best predicted by gender-specific equations of the form: FFM = 5.1 x height1.14 x weight0.41 for men and FFM = 5.34 x height1.47 x weight0.33 for women. In the healthy reference group, indexation of LV mass for BIA-determined FFM and approximated FFM (FFMa), respectively, equally eliminated gender differences in LV mass and markedly reduced the influence of body mass index without affecting the associations between blood pressure and LV mass. Validation of FFMa in two independent population-based samples, aged 52 to 67 years, of the same source population confirmed that LV mass indexed by FFMa produced results that were highly consistent with those obtained with indexation by BIA-determined FFM.

CONCLUSIONS

We propose a novel approximation of FFM based on exponentials of body height and weight. It performed well in the indexation of LV mass in middle-aged men and women of this study. Evaluation of the equation in other populations should be awaited before its use is recommended in situations where direct determination of FFM is not possible.

Body composition and prevalence of left ventricular hypertrophy

BACKGROUND

Fat-free mass (FFM) has been proposed as an optimal normalization of left ventricular (LV) mass to body size. We sought to evaluate the novel FFM-based criteria of LV hypertrophy (LVH).

METHODS AND RESULTS

A population sample of 1371 men and women aged 25 to 74 years was examined by echocardiography and bioelectrical impedance analysis. Internal partition values for LVH were generated in a healthy population subgroup on the basis of LV mass divided by FFM and by the traditional indexations to body height, height(2.7), and body surface area. In contrast to the sex-specific criteria required by traditional indexations, the value of LV mass/FFM that divided individuals with and without LVH was identical for men and women (4.1 g/kg). Estimates of LVH prevalence varied significantly by type of indexation used, internally or externally derived cut points, and by population subgroups. Differences were pronounced among hypertensives and the obese. Thus, the application of LV mass/FFM more than halved the risk of LVH in obese versus nonobese women (odds ratio, 2.5; 95% confidence interval, 1.6 to 4.0) compared with criteria based on LV mass/height(2.7) (odds ratio, 5.5; 95% confidence interval, 3.6 to 8.3). Implications among hypertensives were less marked.

CONCLUSIONS

Indexation of LV mass to FFM eliminates sex-specific LVH criteria. The proportion of individuals defined as having LVH using the new criteria deviate markedly from traditional indexations. Prospective investigations will be needed to identify the prognostic implications of different indexations, especially in subgroups such as the obese.

Gender specific differences in left ventricular adaptation to obesity and hypertension

Recent reports indicate that the prognostic implications of left ventricular hypertrophy (LVH) are more profound in women than in men. The prognosis of LVH is also related to the underlying geometric pattern. We therefore assessed the relation of separate and concurrent influences of obesity and hypertension on gender-specific patterns of LV adaptation. Five hundred and twenty participants of a community-based study (aged 52 to 67 years) were examined by M-mode echocardiography. Study subjects were divided into four groups: normals, obese, hypertensives, and subjects presenting with both obesity and hypertension. The groups were compared for various measures of left ventricular mass (LVM) and geometry. Relative to normal subjects, the increments in wall thickness, ventricle diameters, and LVM were all significant and of similar magnitude for obese men and women. Likewise, hypertensive men and women showed similar relative increments of LVM and wall thickness but no changes in end-diastolic internal diameters. Accordingly, obesity was predominantly associated with eccentric hypertrophy (men +/- 14%, women +17%, P<0.05 vs normals) and hypertension with concentric hypertrophy (men +16%, women +30%, P<0.01 vs normals). Women with concurrent obesity and hypertension presented with a further increase of LVM and wall thickness above values in the merely obese or hypertensive (P<0.001) and they displayed LVH more frequently than only obese or hypertensive women (P<0.05). We conclude that the hearts of postmenopausal women respond more susceptibly to the concurrence of hypertension and obesity. In particular the prognostically less favourable concentric LVH is a common finding. Our study may help to explain the higher risk associated with LVH in women.

Differential effects of antihypertensive drugs on neurohormonal activation: insights from a population-based sample

OBJECTIVES

The clinical course of hypertension or heart failure may be modified by the extent of concurrent neurohormonal activation. Factors that regulate neurohormones in patients with these conditions are complex. In the present study, we examined the relative contribution of antihypertensive therapy to the variability of neurohormonal levels in a well defined population based sample.

DESIGN AND SETTING

Cross-sectional study of a mixed urban and rural population.

SUBJECTS

Middle-aged individuals (n = 646) were analysed in order to elucidate determinants of neurohormone levels by uni- and multivariate comparisons. The assessment included anthropometric, echocardiographic and, if appropriate, genotype information.

RESULTS

The intake of antihypertensive drugs was related to significant alterations of neurohormone levels that, in part, exceeded the contribution of all other variables studied. Multivariate analyses revealed that renin levels were independently related to the intake of beta blockers (n = 80; -8.4 mU L-1; P = 0.001), angiotensin-converting enzyme (ACE)-inhibitors (n = 39; +15.9 mU L-1; P = 0.0001), diuretics (n = 62; +14.3 mU L-1; P = 0.0001), and calcium channel blockers (n = 45; +5.9 mU L-1; P = 0.05). Aldosterone levels were related to ACE-inhibition (-156.5 pmol L-1; P = 0.04) and diuretic treatment (+422.4 pmol L-1; P = 0.0001) in an opposite fashion whereas beta blockers and calcium channel blockers had no significant independent effects. The levels of the atrial natriuretic peptide were significantly related to the use of beta blockers (+3.9 pmol L-1; P = 0.002) and calcium channel blockers (+3.1 pmol L-1; P = 0.05). Finally, serum angiotensinogen levels and ACE activity were not found to be significantly affected by antihypertensive medication but were rather related to gender or genotype.

CONCLUSIONS

The data emphasize that antihypertensive treatment with different classes of drugs may modulate serum levels of neurohormones substantially resulting in distinct patterns of activation. These drug-related effects may require consideration when neurohormonal activation is of functional relevance or when neurohormones serve as prognostic predictors in patients with cardiovascular disorders.

The associations of body size and body composition with left ventricular mass: impacts for indexation in adults

OBJECTIVES

We investigated the relationship between body size, body composition and left ventricular mass (LVM) in adults, and assessed the impact of different indexations of LVM on its associations with gender, adiposity and blood pressure.

BACKGROUND

The best way to normalize LVM for body size to appropriately distinguish physiologic adaptation from morbid heart morphology was discussed.

METHODS

We undertook a community survey of 653 men and 718 women, aged 25 to 74 years. Lean body mass (LBM) was determined by bioelectric impedance analyses and LVM was assessed by two-dimensional guided M-mode echocardiography.

RESULTS

After traditional indexations to body height, body height2.7, or body surface area, men had higher LVM than women (p < 0.001). These gender differences disappeared (p > 0.05) when LVM was indexed to LBM. The type of indexation also modified the strength of the association between adiposity and LVM. The estimated impact of body fat on LVM indexed to LBM was less than half that obtained with traditional indexations. In contrast, the magnitude of the associations of blood pressure with LVM was entirely independent of the type of indexation.

CONCLUSIONS

This study showed the prominent influence of body composition on adult heart size. Indexation for LBM removed gender differences for LVM and reduced the impact of adiposity, but left the effects of blood pressure unchanged. We suggest that this approach be used for clinical and research applications.

Associations between circulating components of the renin-angiotensin-aldosterone system and left ventricular mass

OBJECTIVE

Cardiac growth may be modulated in part by the trophic effects of neurohormones. The aim of the present study was to investigate the relation between the basal activity of the renin-angiotensin-aldosterone system and left ventricular mass.

DESIGN

A population based sample of 615 middle-age subjects was studied by standardised echocardiography; anthropometric measurements; and biochemical quantification of renin, pro-renin, angiotensinogen, angiotensin converting enzyme (ACE), and aldosterone.

RESULTS

Echocardiographic left ventricular mass index correlated significantly with arterial blood pressure, age, and body mass index. In addition, in men ACE activity was significantly related to left ventricular mass index in univariate (P = 0.0007) and multivariate analyses (P = 0.008). Men with left ventricular hypertrophy presented with significantly higher serum ACE concentrations than those with normal left ventricular mass index (P = 0.002). In both men and women serum aldosterone was strongly related to septal and posterior wall thickness. Furthermore, in women serum aldosterone was positively and independently associated with left ventricular mass index (P = 0.0001). This effect was most prominent in hypertensive women. Finally, women with left ventricular hypertrophy presented with significantly higher serum aldosterone (P = 0.01). No significant associations with left ventricular mass index were observed for angiotensinogen, renin, or pro-renin.

CONCLUSIONS

The data suggest that the variability of serum ACE or aldosterone, as occurred in this large population based sample, may contribute to the modulation of left ventricular mass.

[Sex differences in the correlation between obesity and hypertension with left ventricular mass and hypertrophy]

Overweight and hypertension are considered to be independent contributors to the development of left ventricular hypertrophy (LVH). We investigated a selected subgroup (n = 520, aged 52 to 67 years) of participants from the MONICA Augsburg cohort to assess gender-specificity of left ventricular adaptation in response to increasing weight and blood pressure degrees. M-mode-echocardiographic measurements were made and calculated according to the Penn-convention in 293 women and 227 men. LVH was defined as left ventricular mass indexed to height (LVMIm) > 143 g/m in men and > 102 g/m in women (Framingham criteria). Men and women were comparable with regard to increase in LVMIm from the lowest weight and blood pressure group to the highest groups, respectively. In men the increase in LVMIm was 31% from lean to severely obese subjects (111 vs. 145 g/m, p < 0.003) and 25% from normotensive to treated hypertensive subjects (116 vs. 145 g/m, p < 0.0001); in women respective values were 36% (83 vs. 113 g/m, p < 0.0001) and 27% (88 vs. 112 g/m, p < 0.0001). The combined occurrence of obesity and hypertension had an additional effect on left ventricular mass, which was much more pronounced in women than in men. In particular, the increase in LVMIm from the group of lean normotensives to the group of severely obese treated hypertensives was 85% (72 g/m vs. 133 g/m, p < 0.0001) in women and 49% (96 g/m vs. 144 g/m, p < 0.002) in men (p-value for the gender-interaction term < 0.05). The odds ratio for the LVH-prevalence in hypertensive obese subjects as opposed to normal weight normotensive subjects were 11.9 (p < 0.0001) in women and 4.9 (p < 0.0004) in men. In conclusion, we observed for both genders independently and similarly pronounced effects of hypertension and obesity. The combined occurrence of hypertension and obesity had an additional impact on left ventricular mass and hypertrophy, however, in women the effects were significantly more pronounced than in men. The data underscore the effects of hypertension and obesity in the development of LVH. In addition, gender specific factors seem to modulate the effects of these risk factors on left ventricular mass.

Association of angiotensin converting enzyme activity and arterial blood pressure in a population-based sample

OBJECTIVE

To investigate the relationship between circulating angiotensin converting enzyme activity and arterial blood pressure in a population-based sample of 646 middle-aged subjects.

RESULTS

After exclusion of subjects taking antihypertensive medication and those with electrocardiographic evidence of myocardial infarction, univariate analyses revealed that systolic blood pressure was significantly correlated with age and with body mass index. Also, angiotensin converting enzyme activity in men (n = 230) was found to be related both to systolic and to diastolic blood pressure. Inclusion of all of the men slightly strengthened the association between angiotensin converting enzyme activity and systolic or diastolic blood pressure. Multilinear regression models that included age, body mass index and antihypertensive therapy as obligatory covariates confirmed an independent correlation between angiotensin converting enzyme activity and systolic or diastolic blood pressure in the men. Furthermore, untreated men from the highest quartile of angiotensin converting enzyme activity displayed significantly higher mean systolic and diastolic blood pressure values than did those from lower quartiles, even after adjustment for covariates. In contrast, untreated women (n = 264) displayed no evidence for such associations between angiotensin converting enzyme activity and blood pressure.

CONCLUSION

The data suggest that the variability of serum angiotensin converting enzyme activity occurring in this large population-based sample might be related to the level of arterial blood pressure levels in men.

[Masked course of Whipple disease with uveitis, infection, endocardial involvement and abdominal lymphomas--case report and review of the literature]

Whipple's disease is a systemic disease which may virtually affect any organ system, but in many cases it involves the small intestine causing gastrointestinal symptoms. The differential diagnosis is difficult since symptoms may be nonspecific. We report the case of a 44-year old white male patient with a history of migrating arthralgia and chronic fatigue. The patient newly developed an uveitis and underwent a vitrectomy; the further clinical work-up including gastroscopy with intestinal biopsy revealed no sufficient diagnosis. Subsequently, the patient's condition deteriorated with marked weight loss, fever and progressive weakness. An anaerobic sepsis with a corynebacterium was confirmed and with i.v.-antibiotics the patients's condition improved markedly. The further examinations disclosed enlarged mesenteric lymph nodes and the involvement of other organs (endocard, liver). CT-guided biopsy only showed fatty degeneration, but operative adenectomy confirmed Whipple's disease. The patient remained without relapse on long-term antibiotic treatment with doxycycline until today. Obviously, in our case the intestinal biopsies failed to detect Whipple's disease after the successful initiation of antibiotic treatment. In the absence of gastrointestinal findings and with concomitant secondary diseases the definitive diagnosis can be difficult. In addition, the previous uveitis and the endocardial involvement are most interesting.

Cerebral embolism due to left ventricular pacemaker lead: removal with cardiopulmonary bypass

Malposition of a cardiac pacemaker lead within the left ventricle represents a source of early and late thromboembolic complications. We report a case of cerebral embolism, caused by an inadvertently misplaced left ventricular electrode, occurring 3 years after implantation. The lead was removed via a transaortic approach with extracorporeal circulation.

[Atrial septum aneurysm as the cause of a thromboembolic infarction of the brain stem and cerebellum?]

A 32-year-old woman with migraine for several years again had a migraine attack with headache, nausea, vomiting and eye-muscle disorder, 14 days after an uncomplicated delivery. Within 24 hours a left-dominant hemiparesis developed, followed 12 hours later by tonic-clonic seizure and deep unconsciousness (Glasgow score: 3); the patient could not be aroused. Cranial computed tomography revealed extensive infarction of the brainstem and cerebellum. Angiography demonstrated occlusion of the basilar artery but not other abnormalities of other vessels. There was no evidence for vascular anomalies and the clotting tests were normal. Transoesophageal echocardiography demonstrated an atrial septal aneurysm. But any interatrial shunt (e.g. through a patent foramen ovale) was excluded by colour Doppler sonography, making it highly unlikely that a paradoxical embolus was the cause of the infarction. The brainstem infarction resulting from the basilar artery occlusion did not respond to treatment and the patient died 10 days after the initial seizure.

[Echocardiographic and Doppler echocardiographic characterization of left ventricular diastolic function]

For noninvasive assessment of diastolic ventricular function, in addition to echocardiography, more recently, in particular, Doppler echocardiography has been employed. M-mode echocardiogram velocity curves for diameter changes as well as Doppler-echocardiographically registered velocity curves of mitral flow characterize the temporal changes of diastolic flow into the left ventricle. They represent the overall result of factors which influence diastolic filling and are functions of the temporal course of the pressure difference between left atrium and left ventricle. Registration of M-mode and Doppler echocardiograms: For determination of M-mode parameters which should describe left ventricular diastolic function, in addition to the motion of the mitral valve, the left ventricular contours of septum and posterior wall between mitral leaflets and papillary muscles are recorded together with the ECG. For evaluation of the index of atrial emptying, an M-mode registration is obtained from the region of the aortic root. Determination of the Doppler echocardiographic parameters is based on analysis of the blood flow velocity in the region of the mitral valve in the apical four-chamber view with the pulsed Doppler method. Additionally, simultaneous to the Doppler curve, a phonocardiogram is registered or, alternatively, a continuous-wave Doppler registration is obtained which delineates the left ventricular outflow signal and the artefact of mitral valve opening. Parameters for characterization of left ventricular diastolic filling: The first peak of the velocity curve of the diameter change in the M-mode echocardiogram corresponds with the maximal diameter change resulting from early-diastolic filling and the second peak with the maximal diameter change of the left ventricle associated with atrial filling. From this curve as well as the diameter curve relative to time and the mitral valve motion, the times for isovolumetric relaxation as well as the rapid, slow and atrial filling phase which characterize the ventricular filling and the diameter changes of the left ventricle during these time intervals can be derived. The maximal velocity of the diastolic diameter change (PFR) is used to characterize the maximal early diastolic flow. The atrial emptying index characterizes the fraction of filling volume in the first third of diastole with respect to total filling volume of the left ventricle. As an indirect parameter for description of the early-diastolic filling, the steepness of the early-diastolic closure of the anterior mitral leaflet is used. From Doppler velocity profiles of the mitral inflow, early and late diastolic maximal velocities and their velocity time integrals as well as the relationships of these parameters to each other are determined.(ABSTRACT TRUNCATED AT 400 WORDS)