Heavy Metals, Angiogenesis Factors and Osteopontin in Coronary Artery Disease (CAD)
Condition: Ischemic Heart Disease; Coronary Artery Disease; Heavy Metal Toxicity
MeSH terms: Coronary Artery Disease; Myocardial Ischemia; Coronary Disease; Heart Diseases; Heavy Metal Poisoning
Study type: Observational

Summary: 
      The present study aims is to investigate:

        1. whether patients suffering from acute resp. chronic ischemic heart disease show higher
           levels for cadmium (Cd), lead (Pb) and mercury (Hg) than local and international
           reference levels suggest;

        2. the correlation between severity of coronary artery disease and angiogenic and
           angiostatic factors (endostatin-ES, angiostatin-AS, VEGF-vascular endothelial growth
           factor, osteopontin-OPN) The patient population consists of about 270 female and male
           patients suffering either acute or chronic ischemic heart disease (AIHD:ICD-10 I21;
           CIHD: ICD-10 I25).

        3. whether patients suffering CAD and valve calcification (mitral annulus, aortic valve)
           show higher levels of endostatin, angiostatin, osteopontin and VEGF compared to patients
           with CAD but without valve (annulus) calcification The measurement of cadmium (urine),
           lead, mercury, zinc, endostatin, angiostatin, VEGF (serum) and osteopontin (plasma) in
           patients with angiographically verified coronary artery disease are in the fore.
           Furthermore, basic laboratory diagnostics as well as data from coronary angiography and
           echocardiography will be collected. Additionally, the investigators will inquire heavy
           metal exposition during life by an interview.

      Recruitment will be done during the in-patient stay at the General Hospital of Vienna,
      Medical University of Vienna.
    

Detailed description: 
      Patients with angiographically verified CAD of different severity were recruited at the
      Department of Cardiology, Medical University of Vienna. Detailed anamnestic and clinical data
      was collected incl. cardiovascular risk factor assessment, medication, ECG
      (electrocardiogram), routine laboratory parameters, echocardiography and all patients
      underwent an coronary angiography for diagnostic and/or therapeutic reasons on grounds of
      their underlying disease. The coronary artery system was divided into 17 segments and
      stenosis grade for each segment was measured. The segments were: left main,
      proximal/medial/distal LAD (lad left anterior descending artery), ramus circumflex, first and
      second marginal branch, posterolateral branch, first and second diagonal branch,
      proximal/medial/distal LCX (lcx left circumflex artery), proximal/medial/distal RCA (right
      coronary artery), ramus interventricular posterior and stenosis grade for each segment was
      measured. A simple 3-point-grading system ("Coronary Score") was developed considering both
      frequency and severity of CAD: 0 points for non-stenosed or only calcified segments, 1 point
      for each stenosis from <30-<50 %, 2 points for each stenosis from 50-<70 % and 3 points for
      each stenosis >70 %. Blood samples for determination of ES, AS and VEGF levels were taken at
      least two days before or after an acute event (angina pectoris, STEMI-ST-elevation myocardial
      infarction, NSTEM-Non ST-elevation myocardial infarction) or an invasive intervention
      (angiography). ES, AS and VEGF were analysed in serum, OPN in plasma by ELISA-Enzyme Linked
      Immunosorbent Assay according to the instructions of the manufacturer.

      Echocardiography was performed to evaluate left and right ventricular function (multiple
      cross-sectional views), valve insufficiency/stenosis/calcification and wall movement
      disorders.

      Hg and Pb levels were measured in full-blood, Cd in urine. The outcrop of full-blood samples
      for the determination of Pb and Hg was done by 2 ml ultrapure water and 2 ml nitric acid (68%
      sub-boiled). The sample aliquot was 0,5 ml, backfilling volume 20 ml. The determination of Pb
      and Cd was performed by ICPMS (inductively coupled plasma mass spectrometry) according to the
      ÖNORM EN ISO 17294-2. The determination of Hg was done by AFS (atomic fluorescence
      spectroscopy) according to the ÖNORM EN 17852. The outcrop of urine samples for the
      determination of Cd was done by 2 ml ultrapure water and 2 ml nitric acid (68% sub-boiled).
      The sample aliquot was 5 ml, backfilling volume 20 ml. The detection/quantification limits
      were 0,40/2 μg/l (Pb), 0,067/0,13 μg/l (Hg) and 0,12/0,40 μg/l (Cd). In case the
      quantification limit was undercut, the following expected amounts were used: Cd: 0,3 μg/l,
      Pb: 1 μg/l, Hg: 0,1 μg/l. In case of Cd and Hg Human-Biomonitoring (HBM)-I and II levels and
      in case of Pb reference levels from the German Environmental Agency.

      Physical activity of the patients was defined/quantified as non physical activity, walking
      less 3h/week, walking more than 3 hours/week, sports less than 3 hours/week and sports more
      than 3 hours/week.

      Statistical analysis was done with SPSS 20.0. Continuous and normally distributed data is
      described by means ± standard deviation (SD) and group differences are tested by independent
      sample t-test and correlation were calculated using Pearson's correlation coefficient.
      Continuous data with skew distribution or outliers is described ny median, first and third
      quartile and minimum and maximum. Group differences are tested by Mann-Whitney-U-test and
      correlations were calculated using Spearman's correlation coefficient. For data with values
      below the quantification limit a value below quantification limit was imputed (the same value
      for all these observations) and the non-parametric Mann-Whitney-U-test was used. All tests
      are performed two-sided and p-values ≤ 0,05 were considered significant. The protocol was
      approved by the Ethical Commission of the Medical University of Vienna and informed consent
      was obtained from patients.
    

Time perspective: Retrospective
Sampling method: Non-Probability Sample
Study population: 
        Population will be recruited during their in-patient stay at the General Hospital of Vienna
      
Biospecimen description: 
      Blood, Urine
    
Keywords: cadmium; lead; mercury; zinc; endostatin; angiostatin; VEGF; CAD; osteopontin