Potential Clinical Impact of Abdominal Aortic Calcification on Bone Density Lateral Spine Images

Abdominal aortic calcification (AAC) predicts incident atherosclerotic cardiovascular disease (ASCVD) events and can be accurately identified on densitometric lateral spine images obtained at the time of bone densitometry. Our objective was to estimate the proportion of patients referred for bone densitometry who have a high level of AAC and are not already known to have ASCVD or to be at high risk for ASCVD. AAC was scored on densitometric lateral spine images of 2168 individuals blinded to clinical diagnoses or risk factors using the 24-point Framingham scale. We ascertained preexisting ASCVD diagnoses and risk factors using electronic health record data. We used the risk calculator of the American Heart Association (AHA) and the American College of Cardiology (ACC) to estimate the 10-yr risk of hard ASCVD outcomes (myocardial infarction, death caused by coronary heart disease, or nonfatal or fatal stroke). A high level of AAC (AAC score ≥5) was present in 41 (6.1%, 95% confidence interval [CI]: 4.4%-8.2%) of those aged less than 65 yr, in 253 (23.1%, 95% CI: 20.7%-25.7%) of those aged 65-74 yr, and in 153 (37.8%, 95% CI: 33.0%-42.7%) of those aged 75-80 yr. Among those aged 65-74 yr, 16.9% (95% CI: 14.7%-19.3%) had a high level of AAC and no prior clinical diagnosis of ASCVD, but only 2.4% had a high level of AAC and a predicted 10-yr risk of hard ASCVD outcomes <7.5%. AAC is common among those aged 65 yr and older who were referred for bone densitometry and had no known ASCVD, although these individuals can also be recognized as being at intermediate to high risk using the AHA-ACC ASCVD risk calculator. Further studies regarding the impact of identification of AAC on provider and patient cardiovascular disease risk management choices are warranted.

Semiquantified noncalcified coronary plaque in systemic lupus erythematosus

OBJECTIVE

A major cause of morbidity and mortality in systemic lupus erythematosus (SLE) is accelerated coronary atherosclerosis. New technology (computed tomographic angiography) can measure noncalcified coronary plaque (NCP), which is more prone to rupture. We report on a study of semiquantified NCP in SLE.

METHODS

Patients with SLE (n = 147) with no history of cardiovascular disease underwent 64-slice coronary multidetector computed tomography (MDCT). The MDCT scans were evaluated quantitatively by a radiologist, using dedicated software.

RESULTS

The group of 147 patients with SLE was 86% female, 70% white, 29% African American, and 3% other ethnicity. The mean age was 51 years. In our univariate analysis, the major traditional cardiovascular risk factors associated with noncalcified plaque were age (p = 0.007), obesity (p = 0.03; measured as body mass index), homocysteine (p = 0.05), and hypertension (p = 0.04). Anticardiolipin (p = 0.026; but not lupus anticoagulant) and anti-dsDNA (p = 0.03) were associated with higher noncalcified plaque. Prednisone and hydroxychloroquine therapy had no effect, but methotrexate (MTX) use was associated with higher noncalcified plaque (p = 0.0001). In the best multivariate model, age, current MTX use, and history of anti-dsDNA remained significant.

CONCLUSION

Our results suggest that serologic SLE (anti-dsDNA) and traditional cardiovascular risk factors contribute to semiquantified noncalcified plaque in SLE. The association with MTX is not understood, but should be replicated in larger studies and in multiple centers.

Noncalcified coronary plaque in systemic lupus erythematosus

OBJECTIVE

To study noncalcified coronary plaque (NCP) in systemic lupus erythematosus (SLE).

METHODS

Sixty-four-slice coronary multidetector computed tomography (MDCT) was performed in 39 consecutive patients with SLE. MDCT scans were evaluated semiquantitatively by a radiologist using dedicated software. The presence or absence of NCP in each coronary artery was assessed. Patients with mixed plaque (calcified and noncalcified portions) were included in the NCP group.

RESULTS

The patient group was 90% women, 64% Caucasian, 31% African American, 5% other; mean age 50.5 +/- 9.6 years. Fifty-four percent (21/39) had NCP. Seventy-six percent (16/21) of those with NCP also had coronary calcium (range 0.7 to 1264.1 Agatston units). In univariate analysis, NCP was associated with age (p = 0.01), current nonsteroidal antiinflammatory drug (NSAID) use (p = 0.04), hormone replacement therapy (p = 0.02), current use of immunosuppressive drugs (p = 0.02), current low serum C3 level (p = 0.07), current physician's global assessment of activity (PGA; p = 0.05), and low-density lipoprotein cholesterol (p = 0.04). NCP was not associated with other risk factors for atherosclerosis, including total serum cholesterol, high sensitivity C-reactive protein, and lipoprotein(a).

CONCLUSION

Unlike coronary calcium, which is not associated with SLE activity measures or with active serologies, NCP is more common in patients with SLE with current, 3-, and 6-month activity by PGA. NCP was also associated with the need for current NSAID or immunosuppressive therapy. NCP is an important part of the total atherosclerotic burden in SLE.

Association of coronary aortic calcium with abdominal aortic calcium detected on lateral dual energy x-ray absorptiometry spine images

The association of abdominal aortic calcium (AAC) on lateral spine bone densitometry with coronary artery calcium (CAC) has not been reported. We studied 33 men and 73 women who had CAC scored with electron beam computed tomography at the eighth visit of the Rancho Bernardo study and lateral spine dual-energy x-ray absorptiometry images fully evaluable for AAC at the ninth study visit. The association between CAC level and AAC tertile was assessed by ordinal logistic regression analysis. The odds ratio of having a greater CAC score for those with an AAC score in the top tertile (24-point scale score > or =5) was 6.42 (95% confidence interval 2.28 to 18.1) and using the 8-point scale (score > or =3) was 3.38 (95% confidence interval 1.26 to 9.07) compared with those with AAC scores in the bottom tertiles, adjusted for age, gender, systolic blood pressure, total and high-density lipoprotein cholesterol, smoking status, and diabetes. A 24-point AAC score of > or =5 had a sensitivity of 65% and specificity of 70% to detect a high CAC score (> or =400 points). An 8-point AAC score of > or =3 had a sensitivity of 45% and specificity of 78%. In conclusion, a high level of AAC on lateral spine dual-energy x-ray absorptiometry was strongly associated with coronary artery disease and might be commonly encountered because bone densitometry is indicated for all women aged > or =65 years and all men aged > or =70 years. Its presence should be reported to the patient's physician to identify and manage modifiable risk factors.

Coronary artery disease after radiation therapy for Hodgkin's lymphoma: coronary CT angiography findings and calcium scores in nine asymptomatic patients

OBJECTIVE

Long-term survivors of Hodgkin's lymphoma treated with radiation therapy have an increased incidence of coronary artery disease. The purpose of this study is to describe the coronary CT angiography findings and calcium scores of asymptomatic patients who had mediastinal irradiation for Hodgkin's lymphoma and to evaluate the impact of coronary CT angiography on patient management.

MATERIALS AND METHODS

We evaluated nine consecutive patients, age range 35-60 years, who had been treated for Hodgkin's lymphoma by radiation therapy between the ages of 11 and 27 years. The total mediastinal dose ranged from 34 to 45 Gy. All patients were evaluated with 64-MDCT with calcium scoring followed by CT angiography of the coronary arteries. Imaging findings and clinical follow-up were analyzed.

RESULTS

Eight of nine patients had coronary artery disease. CT showed long segments of diffuse disease; areas of stenosis from soft plaque; and calcification in the proximal right coronary, left anterior descending, and left circumflex arteries. Calcium scores were significantly higher than in other patients of this age group. Additional tests, including selective coronary angiography, were necessary in patients with diffuse disease with calcifications. CT evaluation led to bypass surgery and angioplasty in two patients.

CONCLUSION

Coronary CT angiography and calcium scores are useful tools for evaluation of irradiation-related coronary artery disease. Complementary tests might be necessary in selected patients. Prospective larger studies are needed to better define the role of coronary CT angiography and calcium scores and to establish an algorithm for evaluation and treatment of these patients.

Cancer risks from diagnostic radiology

In recent years, there has been a rapid increase in the number of CT scans performed, both in the US and the UK, which has fuelled concern about the long-term consequences of these exposures, particularly in terms of cancer induction. Statistics from the US and the UK indicate a 20-fold and 12-fold increase, respectively, in CT usage over the past two decades, with per caput CT usage in the US being about five times that in the UK. In both countries, most of the collective dose from diagnostic radiology comes from high-dose (in the radiological context) procedures such as CT, interventional radiology and barium enemas; for these procedures, the relevant organ doses are in the range for which there is now direct credible epidemiological evidence of an excess risk of cancer, without the need to extrapolate risks from higher doses. Even for high-dose radiological procedures, the risk to the individual patient is small, so that the benefit/risk balance is generally in the patients' favour. Concerns arise when CT examinations are used without a proven clinical rationale, when alternative modalities could be used with equal efficacy, or when CT scans are repeated unnecessarily. It has been estimated, at least in the US, that these scenarios account for up to one-third of all CT scans. A further issue is the increasing use of CT scans as a screening procedure in asymptomatic patients; at this time, the benefit/risk balance for any of the commonly suggested CT screening techniques has yet to be established.