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Decrease in Cardiovascular risk on HAART - Coronary Artery Calcification on Electron Beam Computed Tomography: A 6-Year Follow-Up Study of HIV-Infected Patients
[Letters to the Editor]
 
 
  JAIDS Journal of Acquired Immune Deficiency Syndromes:Volume 49(1)1 September 2008pp 113-114
 
Adeyemi, Oluwatoyin M MD; Rezai, Katayoun MD; Akimov, Sergey MD; Hwang, Jessica; Sha, Beverly E MD; Kessler, Harold A MD
 
Rush University Medical Center Chicago, IL "This overall decrease in cardiovascular risk over time, despite continued exposure to antiretroviral therapy, mirrors the observation from the large Veterans Administration (VA) study that showed an overall decrease in cardiovascular or cerebrovascular disease over time.8 It therefore remains important in aging HIV-infected patients to address traditional risk factors such as cigarette smoking and dyslipidemia as important contributors to cardiovascular risk."
 
To the Editor:
 
In 1999 to 2000, a study to determine the prevalence of coronary artery calcification (CAC) measured by electron beam computed tomography (EBCT) was performed in a cohort of 60 asymptomatic HIV-infected male patients 40 years of age, and the results were published in this journal.1 In this study, the first on EBCT in HIV-positive patients, we found that 33% of our patients had detectable CAC and 18% had clinically significant CAC, rates that were not statistically different from those observed in age- and gender-matched controls in the study. Large studies on the incidence of cardiovascular events in patients who had EBCT performed have been published2-5; however, to our knowledge, none have been published in HIV-infected patients.
 
In 2006, we conducted a 6-year follow-up study on our cohort,1 and the goals of the study were to describe the prevalence of cardiac risk factors, the incidence of cardiovascular events (eg, congestive heart failure [CHF], myocardial infarction [MI], cerebrovascular accident [CVA], angina), and the impact of baseline CAC on these events.
 
Chart review and questionnaire formats were used. Data on cardiac events (eg, MI, CVA, CHF, angina), laboratory data, cardiac testing, and medication histories were abstracted from the charts in 59 of the 60 patients. Behavioral data on smoking and lifestyle changes were assessed by a questionnaire administered by telephone to the patients. A 10-year Framingham cardiovascular risk (FCR) score6 was calculated based on current status and also retrospectively to obtain baseline scores in 1999/2000. Patients were classified as low risk (<10% 10-year cardiac risk), moderate risk (10% to 20% 10- year cardiac risk), and high risk (>20% 10-year cardiac risk). All data were analyzed in SPSS 10 (SPSS, Inc., Chicago, IL). The study was approved by the Institutional Review Board (IRB) of Rush University Medical Center (Chicago, IL).
 
At the time of review in 2006, 52 (87%) patients were alive, with a mean age of 53 years. The median CD4 count was 599 cells/mm3, and 58% had an HIV RNA level <50 copies/mL. Data on laboratory values and FCR scores at baseline and follow-up are shown in Table 1. All lipid parameters had improved significantly when compared with baseline values. Mean systolic blood pressure or body mass index (BMI) did not change over time. Compared with baseline, there were fewer smokers (39% vs. 23%), fewer patients on protease inhibitors (68% vs. 45%), and more patients on aspirin (23% vs. 8%) and lipid-lowering medications (35% vs. 0%). There was no association between lifestyle changes such as smoking cessation, exercise, or use of lipid-lowering agents and the presence or severity of CAC at baseline (data not shown).
 
FCR was calculated in the 33 patients who had all baseline and follow-up data available (see Table 1). All 4 patients classified as high risk (>20% 10-year risk) at baseline were smokers. The mean FCR for the cohort did not change over the 6-year period, but fewer patients were classified as high risk when compared with baseline (6% vs. 12%). Two patients with a baseline CAC score of 0 had a positive cardiac stress test during the 6-year follow-up period.

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There were 7 deaths in this cohort, and in 4 of these patients, baseline CAC scores were high (205 to 2119). The 2 cardiac deaths (attributable to MI) occurred in patients with elevated CAC scores of 550 and 2119 at baseline. The cause of death could not be ascertained in the other 5 patients.
 
In this cohort of HIV-infected male patients who had EBCT scans done 6 years ago, 2 patients with extremely high CAC scores died as a result of MI. In 4 large published studies2-5 of more than 4000 patients, CAC score, as determined by EBCT, was an independent predictor of cardiac events, even after controlling for other risk factors. These studies concluded that CAC is associated with an increased risk of coronary heart disease (CHD) events in asymptomatic men and women.
 
In our cohort, lipids and glucose values improved over time significantly despite aging and likely reflect lower protease inhibitor use and increased use of lipid-lowering agents. The increasing use of lipid-lowering agents in HIV-positive patients was well demonstrated in a recent analysis of the large data collection on adverse events of anti-HIV drugs (D:A:D) cohort.7 Interestingly, we noted that modifications in risk factors were independent of CAC score in our cohort. Smoking cessation occurred in 9 (42%) of the baseline smokers, and no patient started smoking after baseline. In patients with baseline and follow up FCR scores, 3 (23%) and 1 (25%) patients in the moderate- and high-risk categories, respectively, quit smoking, a rate higher than the 5% to 16% observed in the D:A:D cohort patients with established cardiovascular disease or diabetes.7 This rate of smoking cessation likely contributed to the overall unchanged FCR scores despite a 6-year increase in age and continued use of highly active antiretroviral therapy (HAART). Also, notably, the proportion of patients classified as high risk based on the FCR score was lower compared with baseline.
 
This overall decrease in cardiovascular risk over time, despite continued exposure to antiretroviral therapy, mirrors the observation from the large Veterans Administration (VA) study that showed an overall decrease in cardiovascular or cerebrovascular disease over time.8 It therefore remains important in aging HIV-infected patients to address traditional risk factors such as cigarette smoking and dyslipidemia as important contributors to cardiovascular risk.
 
In conclusion, we found that in a 6-year follow-up study on EBCT, the 2 confirmed cardiovascular deaths occurred in patients with elevated CAC scores at baseline.
 
 
 
 
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