Israel Medical Association Journal

Background: Chlamydia pneumoniae has previously been associated with higher prevalence of valvular and cardiac calcifications.

Objectives: To investigate a possible association of seropositivity for C. pneumoniae and the presence of cardiac calcifications (mitral annular or aortic root calcification, and aortic valve sclerosis).

Methods: We retrospectively analyzed serological data (immunoglobulin G TWAR antibodies) from the AZACS trial (Azithromycin in Acute Coronary Syndromes), and correlated the serological findings according to titer levels with the presence of cardiac calcifications as detected by transthoracic echocardiography.

Results: In 271 patients, age 69 ± 13 years, who underwent both serological and echocardiographic evaluation, we found no significant association between the "calcification sum score" (on a scale of 0–3) in seropositive compared to seronegative patients (1.56 ± 1.15 vs.1.35 ± 1.15, respectively, P = 0.26). The median "calcification sum score" was 1 (interquartile range 0–3) for the seronegative group, and 2 (interquartile range 0–3) for the seropositive group (P = 0.2757). In addition, we did not find a significant correlation of any of the individual sites of cardiac calcification and Chlamydia pneumoniae seropositivity.

Conclusion: Our findings suggest that past C. pneumoniae infection may not be associated with the pathogenesis of valvular and cardiac calcifications.
 

Objectives: To determine whether there is an association between the presence and severity of adult calcific aortic stenosis and Chlamydia pneumoniae seropositivity

Methods: Forty adult patients (23 women, 17 men) were divided into three groups according to echocardiographic aortic valve area: Group A – 7 symptomatic subjects (age 67 ± 7 years) with normal aortic valve and normal coronary angiogram, Group B – 16 patients (age 73 ± 6) with moderate ACAS[1] (AVA[2]> 0.8 £ 1.5 cm²), and Group C – 17 patients (age 76 ± 7) with severe ACAS (AVA £ 0.8 cm²). We tested for immunoglobulins M, G and A as retrospective evidence of C. pneumoniae infection using the micro-immunofluorescence method. Past C. pneumoniae infection was defined by IgG titer > 16 £ 512.

Results: No patients in Group A showed positive Ig[3] for C. pneumoniae. IgM was not detected in any of the patients with ACAS (groups B and C) while 2 of 17 patients (12%) in group C showed IgA for the pathogen. High titers of IgG were found in 14 of 33 (42%) of the patients with moderate or severe ACAS: 5 of 16 (31%) in group B and 9 of 17 (53%) in group C (P = 0.2). Both groups had the same prevalence of coronary artery disease (66%). AVA was lower in IgG-seropositive patients than in the seronegative group (0.88 ± 0.3 cm² vs. 1.22 ± 0.4 cm², respectively, P = 0.02).

Conclusions: Past C. pneumoniae infection may be associated with a higher prevalence and greater severity of ACAS.

Background: Recent studies have suggested a possible association between Chlamydia pneumoniae infection and coronary heart disease.

Objectives: To determine titers of antibodies to Chlamydia pneumoniae in patients with acute  myocardial infraction compared with titers in several control groups.

Methods: This prospective case-control study investigated 209 individuals. We assessed the serum IgG antibody titers to Chlamydia pneumoniae in 57 consecutive patients admitted with AMI to our intensive coronary care unit during a 4 month period. A serum sample was drawn upon admission after 6 weeks. Results were compared with those of four control groups: a) patients admitted with community-acquired pneumonia (n=18), b) patients with community-acquired urinary tract infection (n=42), c) patients with angiographically normal coronary artery disease (n=44), and d) patients with stable coronary artery disease (n=48). Serum immunoglobin G antibody titers to C. pneumoniae were determined using standard micro-immunofluorescene technology.

Results: Of 57 patients with AMI, 32 (56%) had a high lgG titer to C. pneumoniae (>=1:256) on the initial test, which remained unchanged (62%) after 6 weeks. The percentage of patients with high titers was significantly lower in the control groups: 5 of 18 patients (28%) in the pneumonia group (P<0.01), 11 of 42 (26%) in the urinary tract infection group (P<0.01), 11 of 44 (25%) with normal coronary arteries (P<0.01), and 17 of 48 (35%) with stable chronic ischemic heart disease (P<0.05).

Conclusion: The detection of high titers of lgG antibodies to C. pneumoniae in many patients with AMI, compared to control groups, suggest that chronic Chlamydia pneumoniae infection plays a role in the pathogenesis of atherosclerosis and acute ischemic events.

Objectives: To evaluate the association between chronic infection with C. pneumoniae, as measured by a high titer of IgG antibody, and CAD. Our study was designed to explore the relationship between seropositivity to C. pneumoniae and serious coronary events, and to assess whether or not there may be an additional association between established cardiovascular factors and infection with this organism.

Methods: The serum of 130 patients with proven CAD was tested for the presence of IgG antibodies to C. pneumoniae using an ELISA test. A titer ≤1:64 using the microinfluorescence method, the recognized "gold standard," correlates with a positive result when using the ELISA method. The mean age was 57 (40-65 years). The patients, 82% male and 18% female, had either myocardial infarction (n=109) or unstable angina (n=21) 6 months before the investigation (range 3-24 months). The serum for the control group was obtained from 98 blood donors from the same area matched for age 52 (40-58 years) and sex. The donors had no known cardiac history.

Results: In the CAD group 75% of patients were positive for C. pneumoniae compared to 33% in the control group (P=0.001). No increased correlation could be demonstrated between traditional risk factors and C. pneumoniae infection, except in those patients with diabetes mellitus. We found a lower prevalence of IgG antibody to C. pneumoniae in the diabetes subgroup than in other subgroups (P<0.006), but a higher prevalence than in the control group.

Conclusions: We demonstrated a more than twofold increase in seropositivity to C. pneumoniae among patients suffering serious coronary events, and this trend was independent of gender, age or ethnic group. These findings suggest that chronic C. pneumoniae infection may be a significant risk factor for the development of CAD, but this correlation should be investigated further.

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CAD= coronary artery disease