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Improvements in survival after a heart attack

Researchers with a large study called DAD have reviewed cases of heart attacks that occurred between 1999 and 2014 among HIV-positive people. The proportion of participants who died within the first month of a heart attack decreased in the latter years of the study. This effect was likely due to the combination of surgery and prescription medicines to treat cardiovascular disease. Despite this trend in better survival, risk factors for cardiovascular disease remained relatively common throughout the span of the study.

Study details

The DAD study has accumulated health-related information on about 50,000 HIV-positive participants. Data are collected principally from clinics in Europe and also from some sites in the U.S., Argentina, Australia and Israel.

Results

A total of 1,008 heart attacks were recorded between 1999 and 2014—about 2% of participants had heart attacks.

The average profile of participants at the time they had a heart attack was as follows:

  • age – 51 years
  • 91% men, 9% women
  • three common risk factors for heart attack were distributed as follows – 66% of participants had abnormal levels of cholesterol/triglycerides in the blood; 53% smoked tobacco; 43% had higher-than-normal blood pressure
  • 36% were taking drugs for abnormal cholesterol levels and 27% were taking drugs to help reduce elevated blood pressure
  • 90% were taking ART

Results—Trends

DAD obtained information on heart attacks from the clinical records of participants. A team of DAD researchers then reviewed the information on heart attacks and classified heart attacks in the following ways:

  • a heart attack definitely occurred
  • a heart attack possibly occurred
  • unable to classify if a heart attack occurred

Focusing only on cases in which researchers were certain that a heart attack occurred, rates were stable throughout the study. When taking both definite and possible heart attacks into account, researchers found that rates of heart attacks decreased over the course of the study.

Here are some trends:

In the early years of the study, the average age at which a heart attack occurred was 48 years. By the latter years of the study, the average age for this event rose to 54.

Over time, more participants who had a heart attack also had elevated blood pressure and abnormal cholesterol levels in their blood. Also, scores from cardiovascular disease risk calculators, such as the Framingham risk score, rose. This suggests that, over time, the cardiovascular disease risk of participants in DAD was increasing.

Causes of death after a heart attack

On average, people who had a heart attack were monitored for four years. In total, 117 (12%) of 1,008 participants had a second heart attack.

Of the 1,008 participants who had at least one heart attack, 339 (34%) died. These deaths were distributed as follows:

  • 43% of deaths occurred on the same day as the heart attack
  • 11% of deaths occurred within the first month of the heart attack
  • 46% of deaths occurred more than one month after the heart attack

The death rate within the first month of a heart attack changed according to different periods of the study, as follows:

  • 1999 to 2002 – 27% died within the first month of a heart attack
  • 2011 to 2014 – 8% died within the first month of a heart attack

The researchers also sought to assess the impact of a stroke on survival. They found that the proportion of participants dying from a heart attack or stroke fell dramatically from 73% in the period 1999 to 2002 to 41% in the period 2011 to 2014. In contrast, over time, deaths rose from the following causes:

  • AIDS
  • cancers unrelated to AIDS
  • bacterial infections
  • lung disease

After a heart attack

Only some participants underwent invasive cardiac surgery to help improve their flow of blood. Below are the proportions of participants who underwent specific procedures:

  • 1% had endarterectomy – surgery to remove the deposits of plaque from the wall of an artery
  • 9% had coronary bypass surgery – in this type of intervention, surgeons remove one or more blood vessels, usually from the legs, and insert them in the chest to help blood flow around blocked arteries
  • 58% had angioplasty – surgery to widen arteries and keep them open

About two-thirds of these procedures were done on the same day that a heart attack occurred.

Doctors also prescribed the following categories of drugs for a majority of participants who were not already taking them:

  • drugs to lower abnormal lipid levels
  • drugs to decrease the formation of unnecessary blood clots
  • drugs to lower blood pressure

Statistical analysis found that the combination of surgery and medications within the first month of a heart attack was associated with a significant reduction in the risk of short-term death.

Heart attacks and survival

Taking many issues into account, the researchers found that the following factors were associated with an increased risk of death after a heart attack even when interventions (surgery and/or drugs) were made):

  • older age
  • history of injecting street drugs
  • type 2 diabetes
  • history of a heart attack

Bear in mind

In this analysis from DAD, about 2% of 50,000 participants developed a heart attack between 1999 and 2014.

Overall, the risk of a heart attack seemed to decrease during the course of the study. A similar trend has been reported among HIV-negative people in high-income countries.

HIV-positive people who had a heart attack generally were at elevated risk for cardiovascular disease. This finding means that there are opportunities for doctors and their patients to help lower the risk for heart attacks.

Over the course of the study, there was an increase in the use of interventions shortly after a heart attack occurred and this reduced the short-term risk of death.

Toward the latter years of the study, the risk of death in the short term after a heart attack fell about threefold. According to the DAD team, this improvement in survival “appeared to be largely driven by improved clinical management.”

The researchers noted that “there is still a proportion of individuals surviving their heart attacks who do not appear to receive [cardiac surgery and cardiovascular medicines].” The DAD team is not certain why this is the case and advanced this explanation: “complicating [co-existing health conditions] influencing the eligibility of a person to undergo invasive cardiac procedures, the type of heart attack, and differences in clinical practices at different clinical centres may [explain why some people did not receive cardiac surgery and cardiovascular medicines].”

There are limitations to the ability of DAD to analyse the data, as it is an observational study. Also, DAD did not receive information from the clinics that supplied data on whether they provided smoking cessation services or advice about healthy changes to dietary habits or exercise. Hopefully, the clinics that provide care for HIV-positive people with heart attacks will be able to improve the survival of all of their patients in the future.

Resource:

HIV and cardiovascular disease – CATIE fact sheet

—Sean R. Hosein

REFERENCE:

Hatleberg CI, Ryom L, El-Sadr W, et al. Improvements over time in short-term mortality following myocardial infarction in HIV-positive individuals. AIDS. 2016 Jun 19;30(10):1583-96.