Aortic valve implantation-induced conduction block as a framework towards a uniform electrocardiographic definition of left bundle branch block

Introduction

New-onset left bundle branch block (LBBB) following transcatheter or surgical aortic valve replacement (LBBB_AVI) implies a proximal pathogenesis of LBBB. This study compares electrocardiographic characteristics and concordance with LBBB definitions between LBBB_AVI and non-procedure-induced LBBB controls (LBBB_control).

Methods

All LBBB_AVI patients at Ghent University Hospital between 2013 and 2019 were enrolled in the study. LBBB_AVI patients were matched for age, sex, ischaemic heart disease and ejection fraction to LBBB_control patients in a 1:2 ratio. For inclusion, a non-strict LBBB definition was used (QRS duration ≥ 120 ms, QS or rS in V1, absence of Q waves in V5-6). Electrocardiograms were digitally analysed and classified according to three LBBB definitions: European Society of Cardiology (ESC), Strauss and American Heart Association (AHA).

Results

A total of 177 patients (59 LBBB_AVI and 118 LBBB_control) were enrolled in the study. LBBB_AVI patients had more lateral QRS notching/slurring (100% vs 85%, p = 0.001), included a higher percentage with a QRS duration ≥ 130 ms (98% vs 86%, p = 0.007) and had a less leftward oriented QRS axis (−15° vs −30°, p = 0.013) compared to the LBBB_control group. ESC and Strauss criteria were fulfilled in 100% and 95% of LBBB_AVI patients, respectively, but only 18% met the AHA criteria. In LBBB_control patients, concordance with LBBB definitions was lower than in the LBBB_AVI group: ESC 85% (p = 0.001), Strauss 68% (p < 0.001) and AHA 7% (p = 0.035). No differences in electrocardiographic characterisation or concordance with LBBB definitions were observed between LBBB_AVI and LBBB_control patients with lateral QRS notching/slurring.

Conclusion

Non-uniformity exists among current LBBB definitions concerning the detection of proximal LBBB. LBBB_AVI may provide a framework for more consensus on defining proximal LBBB.

Supplementary Information

The online version of this article (10.1007/s12471-021-01565-8) contains supplementary material, which is available to authorized users.

620 Normalized stroke volume in severe aortic stenosis with preserved ejection fraction: reference values and outcome implications

Funding Acknowledgements

none

Background

Appropriate normalization methods to scale Doppler-derived stroke volume (SV) in patients with aortic stenosis (AS) are poorly defined and reference values are lacking.

Purpose

We aim to establish reference values for normalized SV, to compare the prognostic value of SV normalized by different methods in AS and to examine the outcome of low-flow(LF) low-gradient(LG) AS with preserved ejection fraction(LVEF) based on newly defined reference values.

Methods

In 2781 normotensive adults without cardiovascular disease we defined normal relationships between SV and body size by nonlinear regression. We analyzed the prognostic performance of ratiometric and allometric normalized SV in 1450 patients with severe AS and preserved LVEF.

Results

The allometric exponents that described the SV-height (H) and SV-body surface area (BSA) relationships were 1.32 and 0.88, respectively. In males, LF reference values were: &lt;28ml/m²,&lt;30ml/m,&lt;30ml/(m²)^0.88, and, respectively,&lt;26 ml/m^1.32, and in females &lt;27ml/m²,&lt;28ml/m,&lt;29ml/(m²)^0.88, and, respectively,&lt;24 ml/m^1.32. In patients with severe AS, SV/H^1.32 was most consistently associated with mortality and showed better prognostic performance than other normalized SV parameters. Compared to H-normalization, BSA-normalization markedly overestimated the frequency of LF (2% vs. 11%). In 1354 AS patients managed initially medically, LF/LG AS defined based on the 35ml/m² cut-off showed better outcome than high gradient(HG) AS (adjusted HR 0.85[0.62-0.96]). When new reference values were used, the mortality risk of LF/LG AS was higher than that of HGAS (adjusted HR 1.37[1.06-1.89] for SV/BSA and adjusted HR 1.42[1.10-2.15] for SV/H^1.32).

Conclusion

We provide reference values and appropriate normalization methods for SV by Doppler-echocardiography. Patients with LG severe AS, preserved LVEF and "true" LF are at high risk of death during follow-up.

Abstract 620 Figure. Frequency of flow-gradient patterns

P576The first handheld device for autonomic self-detection of symptomatic acute coronary artery occlusion: feasibility, performance and implications for time-efficient self-triage of outpatients with CAD

Background

Time delay between onset of symptoms and seeking medical attention is a major determinant of mortality and morbidity in patients with acute coronary artery occlusion (ACAO). Response time might be reduced by reliable self-detection of ACAO. Currently no self-applicable device can accurately detect ACAO. We have recently shown that an automatic algorithm based upon a three lead system (RELF method) accurately detects ACAO.

Purpose

In this multicenter observational study we tested the operational feasibility, sensitivity and specificity of our RELF method, built into a mobile handheld device, for detection of ACAO.

Methods

Patients with planned elective percutaneous coronary intervention (PCI), who were able to use a smartphone, were asked to perform random ambulatory self-recordings for at least one week. A similar self-recording was made before angioplasty and at 60 s of balloon occlusion.

Results

The operational feasibility of ambulatory self-recordings in enrolled patients with CAD was 59/64 (92.1%, 95% CI: 83.0–96.6). Of all self-recordings 91.1% (n=4567) were automatically classified as successful within one minute. The mean false positive rate during daily life conditions was 4.19% (95% CI: 3.29–5.10). Amongst 65 balloon occlusions, 63 index-tests at 60 s of occlusion were available. The sensitivity for the target conditions “ACAO”, “ACAO with ECG changes” and “ACAO with ECG changes and ST segment elevation myocardial infarction (STEMI) criteria” was respectively 55/63 (0.87; 95% CI: 0.77–0.93), 54/57 (0.95; 95% CI: 0.86–0.98) and 35/35 (1.00). The figure depicts all (n=3936) ST difference vector (STDVn) measurements obtained during ambulatory postural changes, exercise and coronary artery occlusion with and without ECG changes and/or STEMI criteria. Receiver Operator Curve (ROC) for ACAO at different cut-off values of the magnitude of STDVn was 0.973 (95% CI: 0.956–0.990).

Boxplots of all STDVn test recordings

Conclusions

Self-recording with our RELF device is feasible for the majority of patients with CAD. The sensitivity and specificity for automatic detection of the earliest phase of acute coronary artery occlusion support the concept of our RELF device for patient empowerment to reduce delay and increase survival without overloading emergency services. This is the first clinical study that confirms the proof-of-concept of self-detection of acute coronary artery occlusion in outpatients with CAD.

Acknowledgement/Funding

Ghent University, Industrial Research Fund (IOF reference: F2015/IOF-advanced/084).

P3372Prediction of outcome in functional mitral regurgitation using the average pixel intensity method

Background

Functional mitral regurgitation (FMR) is a frequent finding in patients with systolic heart failure. However, the echocardiographic grading of MR is challenging and different severity cut-offs are recommended by international guidelines. We developed and validated a novel echocardiographic parameter to grade MR, the average pixel intensity (API) method, based on pixel intensity analysis of the continuous wave Doppler signal.

Purpose

In this study, we assessed the long-term predictive value of the API method on clinical endpoints in FMR.

Methods

Transthoracic echocardiography was performed in consecutive heart failure patients with reduced EF (HF-REF) (n=221). MR was assessed using the API method, vena contracta width (VCW), effective regurgitant orifice area (PISA-EROA) and regurgitant volume (PISA-RV). The primary clinical events were major adverse cardiac events (MACE: cardiovascular mortality, mitral valve surgery, percutaneous mitral intervention or heart failure hospitalization).

Results

The API method was feasible in 97% of all FMR patients, which was significantly higher than parameters such as VCW, PISA-EROA and PISA-RV. 84 patients (37%) had one or more clinical events during the follow-up period (cardiovascular mortality (20%), mitral valve surgery (5%), percutaneous mitral intervention (5%), heart failure hospitalization (16%) or heart transplantation (2%)). Based on ROC curves, an API cut-off of 121 au was defined as “severe” MVP-MR with an overall better sensitivity and specificity than current guideline-recommended parameters. On multivariate analysis, MR graded with API was independently predictive for clinical events, whereas PISA-based methods were not independent. In addition, pulmonary pressures and NYHA class were powerful independent predictors of clinical outcome in FMR on multivariate analysis.

Conclusions

The API method better predicts clinical events and outcome in FMR compared to established grading methods. Therefore, the API method may be considered for grading FMR severity in clinical practice.

Relationship between Venous and Arterial Haemodynamics during Postural Changes in Venous Insufficiency

Objective:

To study the changes in central haemodynamics and the relationship between arterial blood pressure and the venous dynamics of the lower limbs in patients with venous insufficiency.

Design:

Prospective haemodynamic study during postural changes in 14 patients with venous insufficiency with no other concomitant cardiovascular disease or disturbances in autonomic nervous system.

Setting:

Department of Cardiology and Angiology, University Hospital, Gent, Belgium.

Patients:

Fourteen patients with venous valve insufficiency in the lower limbs.

Interventions:

Measurements of arterial blood pressure, heart rate, stroke volume and cardiac output were performed in the supine position after 30 min rest and 5, 15 and 30 min after standing and during the recovery. Venous pressure at the ankle and calf circumference were also measured.

Main outcome measures:

Changes in cardiac output and total peripheral vascular resistance in order to maintain blood pressure during postural changes.

Results:

Arterial blood pressure was maintained constant owing to an increase in total peripheral vascular resistance despite a decrease in cardiac output. Venous pressure is also related to arterial blood pressure.

Conclusions:

The arterial and venous systems, even in venous insufficiency, are integrated to maintain blood pressure constant during postural changes.

Cardiovascular determinants and prognostic significance of CC Chemokine Ligand-18 (CCL18/PARC) in patients with stable coronary artery disease

Chemokines are important mediators of angiogenesis, hematopoiesis and leucocyte trafficking. CC Chemokine Ligand-18 (CCL18)/ pulmonary and activation-regulated chemokine (PARC) is a circulating chemokine that plays a role in injury healing, physiological homing of mononuclear blood cells and inflammatory responses. CCL18/PARC is also expressed in atherosclerotic plaques. We prospectively evaluated CCL18/PARC levels and their cardiovascular and biological determinants in a large cohort of 285 patients with stable coronary heart disease who were subsequently followed for 3 years for hard cardiac events. It was found that CCL18/PARC levels were associated with decreased cardiac function, decreased exercise capacity and increased inflammatory parameters including interleukin-6 (IL-6) and hs-CRP. More importantly high CCL18/PARC levels were an independent predictor of future cardiovascular events. Therefore, CCL18/PARC is a potential diagnostic and prognostic parameter in patients with stable coronary artery disease.

Numerical validation of a new method to assess aortic pulse wave velocity from a single recording of a brachial artery waveform with an occluding cuff

Recently a new method has been proposed as a tool to measure arterial pulse wave velocity (PWV), a measure of the stiffness of the large arteries and an emerging parameter used as indicator of clinical cardiovascular risk. The method is based on measurement of brachial blood pressure during supra-systolic pressure inflation of a simple brachial cuff [the device is known as the Arteriograph (Tensiomed, Budapest, Hungary)]. This occlusion yields pronounced first and secondary peaks in the pressure waveform, the latter ascribed to a reflection from the aortic bifurcation, and PWV is calculated as the ratio of twice the jugulum-symphysis distance and the time difference between the two peaks. To test the validity of this working principle, we used a numerical model of the arterial tree to simulate pressures and flows in the normal configuration, and in a configuration with an occluded brachial artery. A pronounced secondary peak was indeed found in the brachial pressure signal of the occluded model, but its timing was only related to brachial stiffness and not to aortic stiffness. We also compared PWV's calculated with three different methods: PWVATG (approximately Arteriograph principle), PWVcar-fem (approximately carotid-femoral PWV, the current clinical gold standard method), and PWVtheor (approximately Bramwell-Hill equation). Both PWVATG (R2=0.94) and PWVcar-fem (R2=0.95) correlated well with PWVtheor, but their numerical values were lower (by 2.17+/-0.42 and 1.08+/-0.70 m/s for PWVATG and PWVcar-fem, respectively). In conclusion, our simulations question the working principle of the Arteriograph. Our data indicate that the method picks up wave reflection phenomena confined to the brachial artery, and derived values of PWV rather reflect the stiffness of the brachial arteries.

Poststress left ventricular ejection fraction is an independent predictor of major cardiac events in patients with coronary artery disease and impaired left ventricular function

AIM

The aim of this study was to investigate the prognostic value of myocardial perfusion and function SPECT imaging in patients with coronary artery disease (CAD) and poor left ventricular (LV) function.

METHODS

We studied 261 patients (231 men, age 66+/-10 years) with CAD and a resting LV ejection fraction (LVEF) <or= 40% assessed during myocardial gated SPECT. Perfusion defect extent was calculated using 4D-MSPECT software (Michigan University). Ischemia scoring was performed visually. Considered end points were: 1) major adverse cardiac events (MACE) (cardiac death, non-fatal myocardial infarction or late revascularization), 2) MACE or the need for hospitalization due to heart failure (MACE-HF) and 3) cardiac death or non-fatal myocardial infarction.

RESULTS

During a median follow-up of 31 months, 52 patients (20%) died (35 cardiac deaths), 50 (19%) developed a MACE and 69 (26%) a MACE-HF. In a clinical model, diabetes and angina status were the only predictors of MACE (chi-squared=19.3; P<0.001). By multivariate analysis, poststress LVEF (chi-squared-gain of 6.4; P=0.008) and presence of ischemia (chi-squared-gain of 5.8; P=0.018) were predictive of MACE. Similarly, diabetes mellitus (chi-squared=12.1; P<0.001), poststress LVEF (chi-squared-gain of 5.5; P=0.019) and presence of ischemia (chi-squared-gain of 4.3; P=0.044) were independent predictors of MACE-HF. Diabetes mellitus (chi-squared=17.8; P<0.001), presence of angina complaints (chi-squared-gain of 6.8; P=0.028) and poststress LVEF (chi-squared-gain of 6.3; P=0.008) were independent predictors of cardiac death or non-fatal myocardial infarction.

CONCLUSION

In patients with impaired LV function and CAD, poststress LVEF is an independent predictor of future cardiac events.

Coronary risk factors and inflammation in patients with coronary artery disease and internal cardioverter defibrillator implants

BACKGROUND

The internal cardioverter defibrillator (ICD) is increasingly used to treat ventricular tachyarrhythmias in patients with coronary artery disease (CAD). The burden of coronary risk factors and inflammation is however not well studied in these high risk patients.

STUDY AIMS

The aim of the present study was to describe the prevalence of coronary risk factors (including lipid values) and inflammation (including high sensitive-C-reactive protein, hs-CRP) in patients with CAD and ICD implants.

METHODS

Baseline clinical characteristics and laboratory results of all eligible patients for the Cholesterol Lowering and Arrhythmias Recurrences after Internal Defibrillator Implantation trial (CLARIDI trial) were used. All patients had documented CAD, an ICD implant and were not yet treated with statins. Coronary risk factors, lipid values, glycated haemoglobin (HbA(1c)) and hs-CRP levels were determined.

RESULTS

In the 110 included patients (mean age 68+/-9 years, LVEF 40+/-17%, NYHA class II-III in 47%), a high prevalence of coronary risk factors was documented: current smoking in 18%, body mass index > or =30 kg/m(2) in 16%, blood pressure > or =140/90 mm Hg in 40%, history of diabetes in 12%, and HbA(1c) > or =6% in 16% of patients not known with diabetes. A total cholesterol >175 mg/dl was found in 76% of patients and an LDL cholesterol >100 mg/dl in 83%. Finally, median hs-CRP was 4.8 mg/l (interquartile range 2.5-13.9 mg/l). Hs-CRP values > or =2 mg/l were noted in 83% of all patients and in 68% of patients who had an ICD implant more than 6 months before inclusion.

CONCLUSION

In CAD patients with ICD implants, the burden of coronary risk factors is high, often unrecognized and/or under-treated. Persistent inflammation is found in the majority of these patients.

Assessment of LV diastolic filling using color M-mode Doppler echocardiography: validation in a new hydraulic model

The effect of LV properties on v(p) and the E/v(p) ratio remains a matter of debate. Therefore,the objective of this study is to explore - in a new hydraulic model - the individual contributions of LV relaxation, filling pressure and compliance in changes of E, v(p) and E/v(p) for different stages of diastolic function. A new hydraulic model, consisting of an open cylindrical LA connected to an ellipsoidal LV, is designed. E and v(p) are measured for varying values of tau (45-60-90 ms), LV compliance (0.45-1.35 ml/mmHg) and filling pressure (3-10-30 mmHg). The results are used for predicting the evolution of E, v(p) and E/v(p) during different stages of diastolic function. An increase in compliance decreases E, whereas it augments v(p). v(p) is less load-dependent than E. E decreases with delayed relaxation, increases for the case of pseudonormalisation, and becomes higher than the reference values during restrictive filling. The v(p) value is lower for the case of delayed relaxation than for the reference situation. During pseudonormalisation, the value of v(p) remains lower than the reference value but higher than the value for delayed relaxation. v(p) further decreases during restrictive filling. In conclusion, the effect of simultaneous changes in compliance and loading counterbalance changes in v(p). Therefore, under normal physiologic conditions where load and compliance are coupled, v(p) is apparently load-intensive and E/v(p) increases as filling pressure increases. Moreover, in the different stages of diastolic dysfunction, due to the interference of the co-varying relaxation, the increase in E/v(p) is more pronounced.

Task Force II: blood pressure measurement and cardiovascular outcome

OBJECTIVE

To reach a consensus on the prognostic significance of new techniques of automated blood pressure measurement.

METHODS

A Task Force on the prognostic significance of ambulatory blood pressure monitoring wrote this review in preparation for the Eighth International Consensus Conference (28-31 October 2001, Sendai, Japan). This synopsis was amended to account for opinions aired at the conference and to reflect the common ground reached in the discussions.

POINTS OF CONSENSUS

(1) Prospective studies in treated and untreated hypertensive patients and in the general population have demonstrated that, even after adjusting for established risk factors, the incidence of cardiovascular events is correlated with blood pressure on conventional as well as ambulatory measurement. Ambulatory monitoring, however, significantly refines the prediction already provided by conventional blood pressure measurement. (2) White-coat hypertension is usually defined as an elevated clinic blood pressure in the presence of a normal daytime ambulatory blood pressure. Event-based studies in hypertensive patients have convincingly demonstrated that the risk of cardiovascular disease is less in patients with white-coat hypertension than in those with higher ambulatory blood pressure levels even after controlling for concomitant risk factors. Based on prognostic evidence, white-coat hypertension can now be defined as a conventional blood pressure that is persistently equal to or greater than 140/90 mmHg with an average daytime ambulatory blood pressure of below 135/85 mmHg. The issue of whether or not white-coat hypertension predisposes to sustained hypertension needs further research. (3) There is a growing body of evidence showing that a decreased nocturnal fall in blood pressure (<10% of the daytime level) is associated with a worse prognosis, irrespective of whether night-time dipping is studied as a continuous or a class variable. (4) Intermittent techniques of ambulatory blood pressure monitoring are limited in terms of quantifying short-term blood pressure variability. Proven cardiovascular risk factors such as old age, a higher than usual blood pressure and diabetes mellitus are often associated with greater short-term blood pressure variability. After adjusting for these risk factors, some - but not all - studies have nevertheless reported an independent and positive relationship between cardiovascular outcome and measures of variability of daytime and night-time blood pressure, for example standard deviation. (5) Reference values for ambulatory blood pressure measurement in children are currently based on statistical parameters of blood pressure distribution. In children and adolescents, functional rather than distribution-based definitions of ambulatory hypertension have yet to be developed. (6) Several studies of gestational hypertension have shown that, compared with office measurement, ambulatory blood pressure monitoring is a better predictor of maternal and fetal complications. Pregnancy is a special indication for ambulatory monitoring so that the white-coat effect can be measured and pregnant women are not given antihypertensive drugs unnecessarily. (7) Ambulatory pulse pressure and the QKD interval are measurements obtained by ambulatory monitoring that to some extent reflect the functional characteristics of the large arteries. The QKD interval is correlated with left ventricular mass, and ambulatory pulse pressure is a strong predictor of cardiovascular outcome. (8) Under standardized conditions, the self-measurement of blood pressure is equally as effective as ambulatory blood pressure monitoring in identifying the white-coat effect, but further studies are required to elucidate fully the prognostic accuracy of self-measured blood pressure in comparison with conventional and ambulatory blood pressure measurement.

CONCLUSIONS

Ambulatory blood pressure measurement refines the prognostic information provided by conventional blood pressure readings obtained in the clinic or the doctor's office. Longitudinal studies of patients with white-coat hypertension should clarify the transient, persistent or progressive nature of this condition, particularly in paediatric patients, in whom white-coat hypertension may be a harbinger of sustained hypertension and target-organ damage in adulthood. Finally, the applicability, cost-effectiveness and long-term prognostic accuracy of the self-measurement of blood pressure should be evaluated in relation to conventional blood pressure measurement and ambulatory monitoring.

Vascular changes in workers exposed to carbon disulfide

AIM

To assess the effects of occupational exposure to carbon disulfide (CS2) concentrations below the threshold limit value (31 mg/m3) on the structural and the functional properties of the arteries, heart rate, blood pressure and lipids.

METHODS

Study subjects were 85 male workers in the viscose industry and 35 men without such exposure. The CS2 concentration was determined by personal active sampling. From the common carotid artery diameter, the change in diameter (echography) during the heart cycle and the pulse pressure, local arterial distensibility and compliance were calculated. Global large and small artery elasticity were calculated from registrations of radial artery waveforms. Simultaneously, heart rate and blood pressure were recorded and blood samples were collected for lipid measurements.

RESULTS

CS2 concentrations ranged from 2.34 to 32.4 mg/m3. No significant effect of CS2 on blood pressure, total cholesterol, HDL and LDL cholesterol or triglycerides was found. Among the vascular parameters under study, common carotid artery distensibility was significantly lower, and heart rate significantly higher in exposed workers compared to controls. The differences remained significant after adjustment for age, body mass index, smoking habits, alcohol consumption, heart rate and systolic blood pressure. Common carotid artery intima media thickness and global arterial indices did not differ significantly between the two groups.

CONCLUSIONS

Exposure to CS2 under the current level may already cause alterations in common carotid artery elastic properties in apparently healthy individuals. Even before biochemical and clinical findings occur, important functional changes in the vessel wall were observed, at least in some vascular territories.

Fibrinogen and C-reactive protein on admission as markers of final infarct size after primary angioplasty for acute myocardial infarction

BACKGROUND

In acute myocardial infarction (AMI) treated conservatively or with thrombolysis, marked increases of C-reactive protein (CRP) and fibrinogen have been observed. No data are however available concerning a possible relation between CRP and fibrinogen levels on admission and markers of infarct size after obtaining thrombolysis in myocardial infarction (TIMI) flow III by primary angioplasty.

METHODS

We studied 34 patients with a first AMI (29 men, mean age 54+/-11 years) who were treated with primary angioplasty (TIMI flow III in all patients, no concomitant treatment with glycoprotein IIb-IIIa antagonists) within 6 h of onset of pain. CRP and fibrinogen levels on admission were determined and related to the following markers of infarct size: peak creatine kinase MB (CKMB) levels, radionuclide left ventricular ejection fraction (LVEF) at discharge and thallium-201 single-photon emission computed tomography (SPECT) infarct size at 1 month.

RESULTS

Median CRP levels were 0.4 mg/dl (range 0.09-3 mg/dl), median fibrinogen levels 412 mg/dl (range 198-679 mg/dl), mean CKMB was 178+/-151 U/l, mean LVEF 52+/-8% and mean thallium-201 infarct size 7+/-6%. Although CRP levels were related to fibrinogen levels on admission (r=0.56, P=0.002), only fibrinogen levels were related to markers of infarct size (r=0.58, P=0.001 for CKMB, r=-0.44, P=0.01 for LVEF and r=0.64, P=0.001 for thallium-201 infarct size). No relation was found between CRP or fibrinogen levels on admission and the extent of coronary artery disease or the myocardial area at risk. In multiple regression analysis, the relation between fibrinogen and markers of infarct size was independent of CRP levels and the duration of pain on admission.

CONCLUSIONS

These findings indicate a relation between fibrinogen levels on admission and myocardial infarct size in patients treated with primary angioplasty for AMI. This relation seems to be independent of CRP levels and the duration of pain on admission. If confirmed in larger patient populations, fibrinogen levels on admission could have an important value for risk stratification and more aggressive reduction of infarct size in patients who are treated with primary angioplasty.

Decreased carotid artery distensibility as a sign of early atherosclerosis in viscose rayon workers

Carbon disulphide (CS(2)) is known to accelerate atherosclerosis and to increase the risk for cardiovascular diseases. To assess the effect of CS(2) on the functional (distensibility and compliance) and the structural (intima media thickness) properties of the common carotid artery, and blood pressure and lipid metabolism parameters, a cross-sectional study on 85 workers from a viscose rayon factory and 37 controls was carried out. Exposure to CS(2) was assessed by personal monitoring and was well below the threshold limit value-time weighted average. Carotid arterial wall properties were determined using a non-invasive ultrasound wall movement detector system. No significant effect of CS(2) on blood pressure, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol or triglycerides was found. Among the vascular parameters studied, only distensibility was significantly lower and heart rate was significantly higher in exposed subjects compared with the controls. In conclusion, occupational exposure to CS(2) may cause early alterations in arterial elastic properties in young individuals, and even before lipid and clinical findings have occurred, important functional changes in the vessel wall are present.

Serum vitamin C concentration is low in peripheral arterial disease and is associated with inflammation and severity of atherosclerosis

BACKGROUND

Peripheral arterial disease (PAD) is a severe atherosclerotic condition frequently accompanied by inflammation and oxidative stress. We hypothesized that vitamin C antioxidant levels might be low in PAD and are related to inflammation and disease severity.

METHODS AND RESULTS

We investigated vitamin C (L-ascorbic acid) levels in 85 PAD patients, 106 hypertensives without PAD, and 113 healthy subjects. Serum L-ascorbic acid concentrations were low among PAD patients (median, 27.8 micromol/L) despite comparable smoking status and dietary intake with the other groups (P<0.0001). Subclinical vitamin C deficiency (<11.4 micromol/L), confirmed by low serum alkaline phosphatase activity, was found in 14% of the PAD patients but not in the other groups. Serum C-reactive protein (CRP) concentrations were significantly higher in PAD patients (P<0.0001) and negatively correlated with L-ascorbic acid levels (r=-0.742, P<0.0001). In stepwise multivariate analysis, low L-ascorbic acid concentration in PAD patients was associated with high CRP level (P=0.0001), smoking (P=0.0009), and shorter absolute claudication distance on a standardized graded treadmill test (P=0.029).

CONCLUSIONS

Vitamin C concentrations are lower in intermittent claudicant patients in association with higher CRP levels and severity of PAD. Future studies attempting to relate vitamin C levels to disease occurrence should include in their analysis an inflammatory marker such as CRP.

Extensive deep vein thrombosis in a young woman. Case report

We report a case of a young lady with an extensive deep vein thrombosis (DVT) diagnosed by CT scan and duplex ultrasound examination. Contributory factors were relative immobilisation, oral contraception and hyperhomocysteinemia after methionine loading. No other thrombophilic factors could be found. The three main causes of hyperhomocysteinemia are genetic defects, nutritional deficiencies and insufficient elimination. In our case a genetic defect for one of the key enzymes of homocysteine metabolism, may be the underlying cause. Besides stopping oral contraceptive drugs, anticoagulation and supplementation with pyridoxine and folate was started. Family screening was carried out and revealed other members with hyperhomocysteinemia. Whether therapy with pyridoxine and folate can substantially reduce the recurrence of venous thromboembolic disease remains to be established.

Lipid lowering drugs and recurrences of life-threatening ventricular arrhythmias in high-risk patients

OBJECTIVES

To evaluate a possible effect of lipid lowering drugs on recurrences of ventricular arrhythmias (VA) after implantable cardioverter defibrillator (ICD) implantation.

BACKGROUND

In patients with coronary artery disease (CAD), lipid lowering drugs reduce total and sudden cardiac death. Because the mechanism is not completely understood, we studied whether these drugs have a favorable influence on the occurrence of life-threatening VA in patients with CAD and ICD implants.

METHODS

We conducted an observational study in 78 patients with CAD and life-threatening VA, treated with an ICD. After ICD implantation, 27 patients were on treatment with lipid lowering drugs (group I) and 51 were not (group II). Patients were studied for the following end points: recurrences of VA requiring ICD intervention, cardiac death and hospitalization.

RESULTS

After a mean follow-up of 490 +/- 319 days, 35 patients (45%) had recurrences of VA requiring ICD intervention. In multivariate analysis, the use of lipid lowering drugs (chi-square 6.33, p = 0.012) and poorly tolerated sustained monomorphic ventricular tachycardia as initial presentation (chi-square 4.84, p = 0.028) remained as independent predictors of recurrences of VA. Patients in groups I and II had similar baseline clinical characteristics, but patients in group I had a lower incidence of recurrences of VA (6/27 or 22% vs. 29/51 or 57%, p = 0.004) and of the combined end points of cardiac death and hospitalization (4/27 or 15% vs. 23/51 or 45%, p = 0.015) compared with patients in group II.

CONCLUSIONS

This is the first observation that the use of lipid lowering drugs is associated with a reduction of recurrences of VA in patients with CAD and ICD implants. These data require confirmation in a prospective randomized trial.

Infarct size and recurrence of ventricular arrhythmias after defibrillator implantation

Infarct size as determined by perfusion imaging is an independent predictor of mortality after implantable cardioverter defibrillator (ICD) implantation in patients with coronary artery disease (CAD) and life-threatening ventricular arrhythmias (VA). However, its value as a predictor of VA recurrence and hospitalisation after ICD implantation is unknown. Therefore, the objective of this study was to evaluate whether infarct size as determined by perfusion imaging can help to identify patients who are at high risk for recurrence of VA and hospitalisation after ICD implantation. We studied 56 patients with CAD and life-threatening VA. Before ICD implantation, all patients underwent a uniform study protocol including a thallium-201 stress-redistribution perfusion study. A defect score as a measurement of infarct size was calculated using a 17-segment 5-point scoring system. Study endpoints during follow-up were documented episodes of appropriate anti-tachycardia pacing and/or shocks for VA and cardiac hospitalisation for electrical storm (defined as three or more appropriate ICD interventions within 24 h), heart failure or angina. After a mean follow-up of 470+/-308 days, 22 patients (39%) had recurrences of VA. In univariate analysis, predictors for recurrence were: (a) ventricular tachycardia (VT) as the initial presenting arrhythmia (86% vs 59% for patients without ICD therapy, P=0.04), (b) treatment with beta-blockers (36% vs 68%, P=0.03) and (c) a defect score (DS) > or = 20 (64% vs 32%, P=0.03). In multivariate analysis, VT as the presenting arrhythmia (chi2=5.51, P=0.02) and a DS > or = 20 (chi2=4.22, P=0.04) remained independent predictors. Cardiac hospitalisation was more frequent in patients with a DS > or = 20 (44% vs 13% for patients with DS < 20, P=0.015) and this was particularly due to more frequent hospitalisations for electrical storm (24% vs 3% for patients with DS < 20, P=0.037). The extent of scarring determined by perfusion imaging can separate patients with CAD into high- and low-risk groups for recurrence of VA and cardiac hospitalisation after ICD implantation.

Haptoglobin 1F allele frequency is high among indigenous populations in the state of Durango, Mexico

We studied haptoglobin polymorphism in Mexican populations with high Indian ancestry living in isolated and urban areas in the state of Durango. Analysis with respect to the HP*1F and HP*1S allelic subtypes by isoelectric focusing showed unusually high HP*1F allele frequencies among urban (0.370) and isolated Mexican Indians (0.383). Comparison with other population studies demonstrated a geographical cline of the HP*1F allele increasing in the same direction of the HP*1 allele, while HP*1S frequency does not show racial differences.

Aldosterone and vascular damage

Although the aldosterone escape mechanism is well known, aldosterone has often been neglected in the pathophysiologic consequences of the activated renin-angiotensin-aldosterone system in arterial hypertension and chronic heart failure. There is now evidence for vascular synthesis of aldosterone aside from its secretion by the adrenal cortex. Moreover, aldosterone is involved in vascular smooth muscle cell hypertrophy and hyperplasia, as well as in vascular matrix impairment and endothelial dysfunction. The mechanisms of action of aldosterone may be either delayed (genomic) or rapid (nongenomic). Deleterious effects of aldosterone leading to vascular target-organ damage include (besides salt and water retention) decreased arterial and venous compliance, increased peripheral vascular resistance, and impaired autonomic vascular control due to baroreflex dysfunction.

A non-invasive cardiovascular index for the quantification of arterial load

OBJECTIVE

Our aim is to quantify steady and pulsatile components of arterial load in a concise and sensitive way by means of a new non-invasive cardiovascular index (NICI).

METHODS AND RESULTS

NICI is based on non-invasively measured pressure (sphygmomanometer), stroke volume index and cardiac index (Doppler echocardiography and ECG) and yields a numerical value (in mm Hg). It expresses the difference between the actual arterial load and reference loading conditions as determined in a control group (29 M/35 F, age 34 +/- 13 yr.) of healthy subjects, with blood pressure 116/61 mm Hg (systolic/diastolic), stroke volume index (SVI) 34 +/- 18 ml.m-2 and cardiac index (CI) 2.1 +/- 0.5 l.min-1.m-2. NICI was calculated in the control group and in 23 borderline hypertensive subjects (10 M/13 F, age 65 +/- 12 yr.) with blood pressure 156/79 mm Hg, SVI 36 +/- 10 ml.m-2 and CI 2.4 +/- 0.6 l.min-1.m-2. NICI was higher in borderline hypertensives (33 +/- 51 vs. 0 +/- 34 mm Hg; P < 0.001) and was strongly correlated with total peripheral resistance index (r = 0.89; P < 0.001) and with the ratio of SVI and pulse pressure (r = -0.89; P < 0.001), expressing the combined effect of both known determinants of cardiac load. NICI was also correlated with effective arterial elastance index (r = 0.89; P < 0.001).

CONCLUSIONS

NICI quantifies, within a logical biomechanical framework, the arterial load as seen by the ejecting ventricle. It combines steady and pulsatile components of arterial load and has a single control value of zero mm Hg.

Continuous monitoring of haemodynamic parameters in humans during the early phase of simulated diving with and without breathholding

This study examined the integrative changes of blood pressure (BP) and stroke volume (SV) leading to the initial biphasic heart rate (fc) response (first 15 s) in simulated diving manoeuvres with and without breathholding (BH). Simulated diving was studied in ten young healthy volunteers by application of a gel-filled pack at 0 degree C and 18 degrees C on the forehead with and without BH. Beat-by-beat and second-to-second fc, BP, SV, and total peripheral vascular resistance (TPR) were followed by continuous non-invasive monitoring. In all conditions (BH with forehead cooling at 0 degree and 18 degrees C) there was an early rise in BP triggering the first tachycardial response (fc acceleration) which was immediately counteracted by the concurrent further increase of SV leading to the second phase of early bradycardic response (fc deceleration). Furthermore, the continuous beat-by-beat and second-to-second monitoring allowed the documentation of a highly significant increase of TPR within the first few seconds of the manoeuvres. Our data further indicated that the differences in haemodynamics observed during the stimuli at different temperatures was overruled by BH. Detailed comparisons of the beat-by-beat and second-to-second analyses were unable to show that one method was better than the other. Using continuous non-invasive monitoring of haemodynamic variables during simulated diving manoeuvres it was possible to provide better insights into the physiological principles and meaning of the diving reflex in humans.

Long-term effects of clinical outcome with low and high dose in the Captopril in Heart Insufficient Patients Study (CHIPS)

BACKGROUND

Although angiotensin-converting enzyme inhibitors are recommended as first line therapy in patients with chronic heart failure, the target doses proven to be effective in major morbidity and mortality trials (e.g. captopril 50 mg b.i.d), are generally not used in daily practice in Belgium.

AIM

The objective of this study (CHIPS, Captopril in Heart Insufficient Patients Study) was to compare the long-term effects of a low dose (25 mg b.i.d.) and a high dose (50 mg b.i.d.) of captopril in mild to moderate heart failure. After a titration period of at least 10 days, patients who tolerated 50 mg b.i.d., were randomly assigned to receive either the low dose or the high dose of captopril and followed up to 2 years.

RESULTS

298 patients were included and were followed up for a mean of 12 months. Progression in heart failure seems to be favourably influenced by therapy with high dose in comparison to low dose; a relative difference of 29% in the rates of heart failure worsening was observed between the two doses, 31.5% and 22.4% for low and high dose (p = 0.088), respectively. Treatment with high dose showed also a trend to benefit as compared to low dose in reducing the number of hospitalizations for all causes from 22.4 to 14.5% (p = 0.1) and for congestive heart failure from 14.7 to 7.2% (p = 0.06); moreover, the incidence of fatal and nonfatal cardiac events showed a trend in favour of the high dose of 22% (p = 0.142). The total number of adverse events was comparable for both doses, but dizziness and hypotension were a little more frequently reported in the high-dose group. Serum creatinine values showed no significant changes either in the low-dose or in the high-dose group.

CONCLUSION

In the CHIPS-study, in comparison to a low dose, therapy with a high dose of captopril tends to improve the long-term clinical outcome of patients with mild to moderate heart failure without significantly more toxicity.

Fast determination of haptoglobin phenotype and calculation of hemoglobin binding capacity using high pressure gel permeation chromatography

A new and fast method for haptoglobin (Hp) phenotyping was developed based on high pressure gel permeation chromatography of hemoglobin-supplemented serum. Haptoglobin phenotypes 1-1, 2-1, and 2-2 are resolved on the difference in size of their hemoglobin-haptoglobin complexes. Results are available in less than 15 min. Results of the chromatographic typing correspond to those obtained by conventional starch gel electrophoresis. Next to the phenotyping of haptoglobin, the method allows reproducible calculation of the hemoglobin binding capacity (HBC) of human serum. Using this methodology, reference values for HBC were found to be 0. 75+/-0.25 g/l, with the lowest HBC in Hp 2-2 subjects and the highest in Hp 1-1 subjects (P<0.05). In contrast to earlier findings, the ratio HBC:Hp concentration was found to be comparable for the three Hp types. In conclusion, this method allows a rapid phenotyping in critical clinical conditions where Hp phenotyping can be useful, e.g. determining the donor's phenotype in liver transplantation.

Off-line analysis of red blood cell velocity in renal arterioles

Videomicroscopic methods with off-line analysis of microcirculatory parameters by multifunctional computer-assisted image analysis systems have significant advantages for in vivo microvascular research. A limitation of these methods is, however, that red blood cell velocities (V(RBC)) exceeding 2 mm/s cannot be measured using standard video framing rates. In the present study, a high-speed video camera, recording up to 600 frames per second, was incorporated in the set-up, and V(RBC) was measured off-line with the line-shift-diagram method. The aim of this study was to test the reproducibility and validity of the method using a high-speed video camera and to evaluate its applicability in vivo. V(RBC) were measured in arterioles of the split hydronephrotic kidney. The intra- and interindividual variability was small for V(RBC) below 40 mm/s. The validity of the method was tested using the mass conservation principle and found to be at least as good as that of the dual-slit photometric technique. The present approach extends the application of videomicroscopy coupled to image analysis systems to the analysis of high V(RBC).

Relationship between left ventricular mass index and 24-h urinary free cortisol and cortisone in essential arterial hypertension

OBJECTIVE

Besides arterial blood pressure, nonhemodynamic factors are known to induce cardiac hypertrophy. In Cushing's syndrome, severe ventricular hypertrophy has been linked not only to increased aortic pressure, but also to elevated plasma cortisol. The aim of this study was to examine the relationship between the cortisol/cortisone levels and left ventricular mass index (LVMI) in essential arterial hypertension with and without echocardiographic left ventricular hypertrophy (LVH).

DESIGN

Eighteen untreated Caucasian patients (nine men, nine women, mean age 48+/-6 years) with essential hypertension (163+/-26/100+/-14 mm Hg) were enrolled. An age-matched control group of 13 subjects (seven men, six women) with normotension (121+/-9/79+/-7 mm Hg) were enrolled also. Left ventricular dimensions were echocardiographically assessed and cortisol production evaluated by 24-h urinary free cortisol and cortisone concentrations.

RESULTS

LVMI averaged 115+/-31 g/m2 and 24-h urinary free cortisol and cortisone were 23+/-14 microg per 24 h and 31+/-18 microg per 24 h. Prevalence of echocardiographic LVH was 56%. LVMI correlated significantly with 24-h urinary free cortisol (r = 0.61, P = 0.007) and cortisone (r = 0.60, P = 0.009). Patients with echocardiographic LVH were characterized by higher daytime ambulatory blood pressure, LVMI (particularly the posterior wall), and 24-h urinary cortisol, while office blood pressure, septal: posterior wall ratio and 24-h urinary cortisone were comparable in all patients. In control individuals, LVMI averaged 91+/-18 g/m2 and 24-h urinary free cortisol and cortisone, respectively, were 34.7+/-6.6 microg per 24 h and 64.3+/-10.8 microg per 24 h (P<0.05 versus patients). Neither LVMI nor the contributing ventricular dimensions showed significant correlation with 24-h urinary free cortisol or cortisone in the control group.

CONCLUSIONS

Our data provide evidence for a significant relationship between LVMI and cortisol production independently of arterial blood pressure in untreated mild to moderate hypertension.

Haptoglobin polymorphism and peripheral arterial occlusive disease

Haptoglobin (Hp) 2-2 phenotype is a genetic risk factor in coronary atherosclerosis. In this study, haptoglobin phenotypes were determined in 141 patients with peripheral arterial occlusive disease (PAOD) and compared to a reference population (n = 1000). The relative Hp1 allele frequency was decreased among PAOD patients (0.294 vs. 0.403 for the reference population, P < 0.01) due to an overrepresentation of the Hp 2-2 phenotype (50%, odds ratio 1.82 (95% C.I. 1.28-2.60), P < 0.001). This finding was even more pronounced in non-diabetic and in non-smoking PAOD patients (Hp1 allele frequencies: 0.265 and 0.228, respectively). Serum lipids, inflammatory parameters, and blood pressure levels were comparable among the Hp phenotypes, but serum levels of the antioxidant vitamin C were lower in Hp 2-2 patients than in patients with another phenotype (P < 0.05). In PAOD patients with severe atherosclerotic lesions, maximal walking distance of patients carrying a Hp 2-2 phenotype (225-525 m) exceeded that of other Hp phenotypes (50-242 m) (interquartile ranges) (P < 0.05). The findings demonstrate that, despite an increased risk for developing PAOD, the Hp 2-2 phenotype is associated with a longer maximal walking distance which might be attributed to the earlier reported in vitro angiogenic properties of the Hp 2-2 molecule.

Why is training effective in the treatment of patients with intermittent claudication?

Patients with peripheral arterial obstructive disease (PAOD) often have complaints of intermittent claudication. This causes a great limitation in the quality of life because of reduction in walking ability. PAOD is associated with increased morbidity and mortality. Beside other therapies, training has been shown to be an effective treatment option for patients with intermittent claudication. Exercise training significantly increases walking distance and consequently the functional behaviour of the patient. Several authors have identified different mechanisms involved in this beneficial effect. The most important are discussed in this review, namely adaptation or redistribution of the peripheral blood flow, inhibition of the progression of the atherosclerotic disease, changes in blood rheology, metabolic changes, changes in skeletal muscle morphology, economisation of walking, a change in pain perception and an effect on the cardiovascular system. It is concluded that training works through a combination of mechanisms. Further research is needed to clarify the precise mechanisms.

Reverse redistribution on thallium-201 single-photon emission tomography after primary angioplasty: a one-year follow-up study

The prognostic significance of reverse redistribution (RR) on thallium-201 single-photon emission tomography (SPET) images after acute myocardial infarction (AMI) has not been studied in detail. Moreover, RR data in patients treated with primary angioplasty are lacking. Fifty consecutive patients (including 40 men with a mean age of 54+/-11 years) with a first AMI were treated with primary angioplasty and followed up for 13+/-5 months for the following end-points: death, reinfarction and recurrent angina requiring revascularisation. Admission and peak creatine kinase myocardial enzyme (CKMB) and ejection fraction (EF) at discharge were studied as markers of myocardial damage. Thallium-201 stress-redistribution SPET studies at 1 month were analysed using a 13-segment, 4-point scoring system. Segments showing a worsening of perfusion by at least 1 point on redistribution studies were defined as showing RR. RR was present in 13 (26%) patients (group 1) and absent in 37 (74%) (group 2). Both groups were comparable for age, sex, peak CKMB release, EF and Q-wave myocardial infarctions. TIMI flow 3 was obtained in 92% in group 1 and 95% in group 2 (P = 0.95). On admission, CKMB was significantly lower in group 1 (18+/-14 vs 44+/-41 U/l, P = 0.03). Also, segments showing reversible perfusion were significantly more frequent in group 2 (1/169 vs 57/481, P = 0. 01). During follow-up, no death occurred and the combined documented endpoint of reinfarction and recurrent angina requiring angioplasty or coronary artery bypass grafting was significantly more frequently reached in group 2 (0/13 vs 10/37, P = 0.046). In conclusion, RR is common (26%) after primary angioplasty for a first AMI and is associated with lesser myocardial damage on admission. Patients with RR rarely have reversible segments on 201Tl SPET and tend to have a favourable outcome after 1 year of follow-up.

Mild to moderate hyperhomocysteinaemia in cardiovascular disease

Elevated serum levels of homocysteine, a sulphur-containing amino acid, are increasingly recognized as an independent risk factor for atherosclerotic and thrombotic vascular disease. Presence of a thermolabile variant of methylenetetrahydrofolatereductase and an inadequate folate status are the most common causes of hyperhomocysteinaemia. Homocysteine damages the vessel wall mainly through generation of oxygen radicals and creates a prothrombotic environment. In the majority of cases, normalization of homocysteine levels can be achieved with administration of vitamins of the B-group. The effect of this treatment on cardiovascular outcome, however, remains undefined.

Gallstone recurrence after successful shock wave therapy: the magnitude of the problem and the predictive factors

OBJECTIVE

Reports concerning long term recurrence of gallstones after successful extracorporeal shock wave lithotripsy (ESWL) show a high probability of stone recurrence. There is still discussion on the factors influencing stone recurrence. In this study we wanted to evaluate the long term recurrence of gallstones after stone clearance with ESWL and oral bile acids, and to assess possible risk and preventive factors of stone recurrence.

METHODS

A total of 322 consecutive patients with stone clearance between December 1988 and December 1995 were included. All patients were contacted for ultrasonography and were interviewed for additional information on daily intake of aspirin, NSAIDs, cholesterol lowering medication, estrogen therapy, and biliary pain during follow-up.

RESULTS

A total of 187 patients were still stone-free after a mean follow-up of 35 months (range: 3-89 months); 135 patients had recurrence. There was a significant association between stone recurrence and estrogen intake (p = 0.04), number of lithotripsy sessions (p = 0.0007), time until stone disappearance (p = 0.0003), and biliary pain (p < 0.0001). There was no difference in recurrence rate between solitary and multiple stones.

CONCLUSIONS

Long-term recurrence of gallstones after lithotripsy is high: < or = 69% after 6 yr. We found a significant association of stone recurrence with estrogen intake, number of lithotripsy sessions, and time until stone disappearance. Intake of aspirin or NSAIDs was not associated with decreased stone recurrence. Of the patients with recurrent stones, 57% had biliary pain.

The Selvester 32-point QRS score for evaluation of myocardial infarct size after primary coronary angioplasty

In patients treated successfully with primary angioplasty for a first myocardial infarction, the Selvester 32-point score correlates well with infarct size measured with quantitative thallium-201 perfusion imaging. Therefore, it is a useful parameter for infarct sizing, particularly in patients with anterior infarction or reduced ejection fraction at discharge.

How to study sympatho-vagal balance in arterial hypertension and the effect of antihypertensive drugs?

Blood pressure homeostasis and variability are the resultant of many complicated neurohumoral interactions. The autonomic nervous system plays a key role in the process. Since arterial hypertension is characterized by an increased sympathetic tone, the determination of the sympatho-vagal balance can give more insight in the autonomic nervous function in this pathology. The assessment of sympatho-vagal balance has been derived from reflex manoeuvres as the study of the baroreceptor function by phenylephrine or nitroglycerin test, by the application of negative or positive pressure around the neck or at the lower limbs or by tilting. Other reflex manoeuvres are hand-grip, cold pressure test, Valsalva manoeuvre, mental arithmetics and microneurography, providing information about the sympathetic reflex activity, and deep breathing about vagal reflex activity. These reflex tests have several limitations, because they request cooperation of the patient. Power spectral analysis of beat-to-beat blood pressure and RR-interval recordings permit to evaluate autonomic activity at baseline conditions and to separate the different components of variability which seem to reflect specific regulatory mechanisms. For the RR-interval, the high frequency component (HF) is a marker of vagal activity, while the low frequency component (LF) is a marker of sympathetic and vagal activity. The LF/HF ratio can be considered as a marker of sympatho-vagal balance. The significance of the LF and HF components of arterial blood pressure variability is less clear. Spectral analysis can be used to study the effect of antihypertensive drugs on sympatho-vagal balance.

Effect of haptoglobin phenotypes on growth of Streptococcus pyogenes

The haptoglobin (Hp) 2-1 and 2-2 phenotypes have been shown to agglutinate Streptococcus pyogenes carrying the membrane antigen T4. In this study, the growth rate of two strains of Streptococcus pyogenes (T1 and T4) in human serum was compared among haptoglobin phenotypes in vitro. During incubation for 16 hours in serum of different haptoglobin types, only Hp 2-1 and Hp 2-2 sera showed an inhibitory effect on growth, Hp 2-2 being 1.85 times more potent than Hp 2-1. Growth of Streptococcus pyogenes T4 negatively correlated with the serum concentration of Hp 2-1 (r = -0.908) and Hp 2-2 (r = -0.953). Haptoglobin-depleted serum had no inhibitory effect on bacterial growth. Addition of haemoglobin and ferric citrate to the serum accelerated the growth of Streptococcus pyogenes T4 (P <0.05) but not in Hp 2-2 serum. Haptoglobin types 2-1 and 2-2 can be regarded as inhibitors of Streptococcus pyogenes growth in vitro. These data point towards a potential protective role of Hp 2-2 in Streptococcus pyogenes infection in vivo, independently of iron uptake.

Haptoglobin polymorphism, iron metabolism and mortality in HIV infection

BACKGROUND

Three phenotypes of the antioxidant protein haptoglobin are known: Hp 1-1, Hp 2-1 and Hp 2-2.

OBJECTIVES

To investigate the outcome of HIV infection according to haptoglobin type.

DESIGN AND METHODS

Haptoglobin phenotypes were determined using starch gel electrophoresis in serum obtained from 653 HIV-infected Caucasians in the AIDS reference centers of Gent (n = 184), Antwerp (n = 309), and Luxembourg (n = 160). Survival was compared between haptoglobin types using Kaplan-Meier curves. Plasma HIV-1 RNA was quantified by reverse transcriptase PCR. Serum iron, transferrin saturation, ferritin, and vitamin C were assayed to evaluate iron-driven oxidative stress in 184 HIV-infected patients and 204 controls.

RESULTS

The haptoglobin type distribution amongst the patients (17.6% Hp 1-1, 49.9% Hp 2-1, 32.5% Hp 2-2) corresponded to that of the controls. Kaplan-Meier curves showed a higher mortality for the Hp 2-2 group (P = 0.0001; adjusted mortality risk ratio, 1.78; 95% confidence interval, 1.25-2.54). Median survival time was 11.0 years (Hp 1-1 and Hp 2-1) versus 7.33 years (Hp 2-2). Plasma HIV-1 RNA levels prior to antiviral therapy and their increase over 1 year were highest in Hp 2-2 patients (P = 0.03 and 0.003, respectively). The Hp 2-2 type was associated with higher serum iron, transferrin saturation, and ferritin levels and with low vitamin C concentrations. Furthermore, ferritin concentrations were higher in HIV-infected patients than in controls (P < 0.0001).

CONCLUSION

HIV-infected patients carrying the Hp 2-2 phenotype show a worse prognosis, which is reflected by a more rapid rate of viral replication (in the absence of antiviral treatment). They also accumulate more iron and oxidize more vitamin C, suggesting that less efficient protection against haemoglobin/iron-driven oxidative stress may be a direct mechanism for stimulating viral replication.

Is low serum chloride level a risk factor for cardiovascular mortality?

BACKGROUND

Serum chloride level is routinely assayed in clinical laboratories in the management of patients with kidney disorders and with metabolic diseases. It is a biological parameter that is easily, precisely and relatively cheaply measured. The epidemiological features of serum chloride levels have not been studied before.

METHODS

For the random sample of men and women from the Belgian Interuniversity Research on Nutrition and Health aged 25-74 years, free of symptomatic coronary heart disease at baseline, serum chloride concentrations were measured, among those of other electrolytes. The cohort was followed up for 10 years with respect to subsequent cause-specific mortality.

RESULTS

The results are based on observations of 4793 men and 4313 women. According to Cox regression analysis serum chloride level was one of the strongest predictors of total, cardiovascular disease (CVD) and non-CVD mortalities independently of age, body mass index, sex, smoking, systolic blood pressure, levels of total and high-density lipoprotein cholesterol, uric acid, serum creatinine and serum total proteins and intake of diuretics. This relation was proved to be independent of levels of other serum electrolytes and similar for men and women. The estimated adjusted risk ratio for CVD death for subjects with a serum chloride level < or =100 mmol/l compared with those with levels above that limit was 1.65 (95% confidence interval 1.06-2.57) for men and 2.16 (95% confidence interval 1.11-4.22) for women. The study of adjusted risk ratios for four groups of subjects defined on the basis of their baseline serum chloride levels revealed a decreasing log-linear 'dose-response' relation to total and cardiovascular mortalities.

CONCLUSION

This s the first report from a population-based study to indicate that there is an association between serum chloride level and the incidence of total, CVD and non-CVD mortalities. The risk ratio for CVD mortality associated with a low serum chloride level was comparable to or higher than those observed for well-established CVD risk factors.

Angiotensin I-converting enzyme insertion/deletion polymorphism: clinical implications

Since the identification of an Insertion/Deletion polymorphism in the ACE gene, numerous studies have evaluated the potential risk of the DD genotype in cardiovascular disease and hypertension. The report of many conflicting publications reveals a strong need for reviewing the most important data. There is evidence of the absence of an association between the ACE polymorphism and hypertension in Caucasians. In blacks a positive association between the D allele and high blood pressure was seen, Japanese studies show discrepant results. Several studies showed no association between the ACE polymorphism and the risk of myocardial infarction. However, in certain subpopulations, such as low risk patients or coronary care unit patients, an increased risk of myocardial infarction in DD type is present, and a meta-analysis supports this proposition. Because of conflicting data, the potential association between the ACE polymorphism and coronary artery disease, cerebrovascular disease, left ventricular hypertrophy, hypertrophic and idiopathic dilated cardiomyopathy, carotid artery disease and diabetic and immunoglobin A nephropathy, remains inconclusive.