- Category: Cardiovascular Disease
- Published on Monday, 10 September 2012 00:00
- Written by Liz Highleyman
People with HIV had heart attacks at a younger age than HIV negative individuals and were about 50% more likely to die after an acute myocardial infarction, according to a study presented this week at the 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2012) in San Francisco. A related analysis found that HIV positive people received coronary catheterization at a later stage, after they had more advanced heart damage.
Several studies have shown that people with HIV are at increased risk for cardiovascular disease, though it is not yet clear whether this is due to persistent viral infection, resulting immune activation and inflammation, side effects of antiretroviral therapy (ART), traditional risk factors, or some combination.
Inflammation and metabolic changes related to ART can contribute to atherosclerosis, a process in which artery walls thicken and lose their elasticity as they fill up with plaques of lipids, cell debris, calcium, and scar tissue. Over time, this leads to impaired blood flow to the heart and brain, which can result in a heart attack or stroke. Various procedures may be used to re-expand blocked vessels, but outcomes are better if done early.
HIV and Heart Attacks
Daniel Pearce, DO, from Loma Linda University in California and colleagues compared outcomes between HIV positive and HIV negative patients hospitalized for acute myocardial infarction. They used data from the Nationwide Inpatient Sample, collected from 1997 through 2006, which approximates a 20% sample of all U.S. hospitalizations during this period.
The analysis included a total of 1,428,146 adult participants who spent at least 1 day in the hospital after an acute myocardial infarction; 5984 of them were HIV positive. Most were white men age 55 or older with private health insurance. Co-morbidities were common overall, including hypertension (51%), diabetes (24%), congestive heart failure (20%), and chronic pulmonary disease (16%).
- The in-hospital mortality rate after myocardial infarction was 4.3% for people with HIV, compared with 2.4% for HIV negative participants.
- HIV positive people had a significant 43% higher likelihood of death after admission for myocardial infarction than HIV negative people (hazard ratio [HR] 1.43).
- After adjusting for sex, age, and race/ethnicity, people with HIV had an even greater mortality disparity (adjusted HR 1.64, or 64% higher mortality).
- After adjusting for both demographic and clinical factors including co-morbidities, people with HIV remained at higher risk of death (adjusted HR 1.53, or 53% higher mortality).
- In addition to HIV status, male sex, older age, and greater co-morbidity burden were also significant predictors of death.
- HIV positive patients were younger on average than HIV negative participants --54 vs 64 years -- indicating that they were having heart attacks sooner.
- HIV positive people stayed in the hospital longer on average (6 vs 5 days), incurred higher cost, and were more likely to be on Medicaid or Medicare (62% vs 25%), than HIV negative people.
- People with HIV had more co-morbidity than HIV negative participants, both overall and for specific conditions including congestive heart failure (26% vs 20%), kidney disease (13% vs 5%), and mild liver disease (8% vs 1%).
- However, most other major cardiac and metabolic risk factors -- such as hypertension, diabetes, elevated cholesterol, and smoking -- were less common among people with HIV.
- HIV positive people were significantly less likely than HIV negative people to undergo common coronary procedures:
o Left cardiac catheterization: 52% vs 66%, respectively;
o Coronary arteriography: 48% vs 63%, respectively;
o Left heart angiography: 44% vs 56%, respectively;
o Coronary artery bypass grafting was done less than half as often for HIV positive people.
"A significant additional mortality burden exists" for HIV positive people receiving in-hospital care for acute myocardial infarction, the researchers concluded, and this group has "significantly lower rates" for the most common in-hospital procedures.
Greater risk of acute myocardial infarction and resulting death in people with HIV may be due to direct pathological effects of HIV viremia including arterial endothelial inflammation, intimal fibrosis with luminal narrowing of coronary vessels, endothelial irritation, platelet dysfunction, activation of pro-inflammatory cytokines, thrombosis from reduced coronary blood flow, and ischemia (lack of oxygen), they suggested.
Considering other types of factors that might play a role, they noted that HIV positive people as a group are more likely to be drug or alcohol users and are of lower socioeconomic. However, controlling for these factors did not significantly alter the disparity in mortality.
At an ICAAC media briefing, Pearce suggest that maybe HIV is a "hotter" risk factor than smoking, family history, and other traditional factors.He added that clinicians managing patients with HIV should be more alert for early symptoms such as chest pain, which might not normally raise an alarm in young patients. In addition, HIV positive people might be advised to receive electrocardiograms and start preventive aspirin therapy sooner.
In the second study, Christy Kaiser, MD, Charles Hicks, MD, and colleagues from Duke University Medical Center and the University of North Carolina compared characteristics of HIV positive and HIV negative individuals undergoing first-time coronary catheterization, a procedure in which a catheter is threaded through the blood vessels supplying the heart to diagnose (and sometimes treat) blockages. It is often done when people experience chest pain or have suspected coronary artery disease.
This retrospective analysis included 96 HIV positive people seen at HIV specialty clinics between January 1996 and March 2012. They were matched with 41 HIV negative people of the same sex, age, and socioeconomic status. All participants were in established care (at least 3 visits) before the onset of symptoms leading to catheterization, and they did not have a pre-existing cardiovascular disease diagnosis.
The median age was about 50 years, 75% of HIV positive and 60% of HIV negative participants were men, and approximately 70% were black. Among the HIV positive participants, the average CD4 T-cell count was about 500 cells/mm3. Most were on ART, but the sample size was too small to do an analysis comparing different drugs.
As in Pearce's study, end-stage kidney disease was more common among HIV positive patients (15% vs 0%), but diabetes was more common in the HIV negative group (23% vs 42%). Rates of hypertension, elevated cholesterol, and other traditional cardiovascular risk factors were similar. In contrast with Pearce's findings -- but agreeing with most other studies -- people with HIV were more likely to be tobacco smokers (51% vs 37%), and they were more likely to use cocaine (17% vs 10%).
- More HIV positive people than HIV negative people had "significant" coronary artery disease -- defined as at least 50% blockage of one or more major blood vessels -- at the time of catheterization (63% vs 54%), but the difference did not reach statistically significance.
- HIV positive people were significantly more likely than HIV negative control patients to undergo cardiac catheterization on an urgent basis due to unstable angina or myocardial infarction (54% vs 34%).
- Subsequent clinical management after initial catheterization, including bypass surgery (18% vs 23%) and stent placement (52% vs 46%), was the same in both groups.
"Significant coronary artery disease was common in HIV positive patients going for [catheterization] despite the young median age of 49 years," the researchers concluded.
At the media briefing, Hicks said that it was difficult to find enough HIV negative people who underwent catheterization at such a young age due to suspected coronary artery disease.
Kaiser added that it was also difficult to find matched HIV negative people who were plugged into care, as the team had to exclude 75% of potential participants because they were not in established care. "Young men of low socioeconomic class don’t go to the doctor," she said, adding that being HIV positive might provide an entry into care for other conditions.
"The high proportion of [catheterizations] done in the HIV positive population for myocardial infarction or unstable angina suggests health care providers may not consider coronary artery disease early enough in younger HIV positive patients," the investigators continued. "Earlier recognition of coronary artery disease in HIV-infected patients may help improve outcomes."
"The rates of cardiac stent placement and use [of] cardiac bypass surgery were nearly identical between those with HIV infection and the control population, implying that provider bias against aggressively treating HIV-infected individuals was not an issue," the researchers summarized in an ICAAC press release. "Instead, we suspect that specialist health care providers caring for HIV-infected patients are less experienced than primary care providers at recognizing and treating cardiac risk factors and coronary artery disease."
Hicks suggested that either HIV specialty doctors could become more broadly educated about general medicine, or perhaps many HIV patients could be followed by a generalist for primary care, only going back to specialists when they have HIV-related issues.
"We don't want to be using these tools after heart damage is already done," he cautioned.
C Ani, D Pearce, Y Espinosa-Silva, et al. In-Hospital Mortality from Acute Myocardial Infarction: HIV Sero-positive vs. Sero-negative Individuals. 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2012). San Francisco. September 9-12, 2012. Abstract H-228.
C Kaiser, T Chin, S Napravnik, C Hicks, et al. Early Onset and Late Diagnosis of CAD in HIV+ Persons. 52nd Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2012). San Francisco. September 9-12, 2012. Abstract H-229.
ICAAC/American Society for Microbiology. Unrecognized Heart Disease in HIV+ Patients. Press release. September 9, 2012.