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Gender Gaps Persist for Out-of-Hospital MI, Cardiac Arrest (CME/CE)

Action Points

  • While both women and men with STEMI experienced patient delays (the time from symptom onset to contact with a hospital, emergency medical service, or general practitioner), female gender was independently associated with greater patient delay, in a Swiss study.
  • Note that low rates of administration of evidence-based therapies were observed in a large population of women and men with chest pain or out-of-hospital cardiac arrest who were treated by EMS agencies in the U.S.

CME Author: Zeena Nackerdien

Study Authors: Matthias R. Meyer, Alain M. Bernheim et al., and Jannet F. Lewis, Scott L. Zeger, et al.

Target Audience and Goal Statement:

Cardiologists and emergency department physicians

The goal was to clarify to what extent gender differences exist in the treatment of cardiovascular disease (CVD) in Switzerland and the U.S.

Background and Questions Addressed:

When arteries of the heart are narrowed or blocked (almost always due to fatty deposits in the blood vessel), the resulting coronary heart disease (CHD) can have devastating consequences, such as arrhythmias, ischemia (silent and overt), angina (stable and unstable), myocardial infarction (MI, heart attack), heart failure, and sudden death.

Ischemic heart disease is the leading cause of death in both men and women. Most research on hospital and post-hospital interventions have noted that women are less likely to receive evidence-based therapies for acute MI (AMI), but results may have been confounded by sociodemographic characteristics, capacities at point of care, and small sample sizes.

The questions addressed by the two studies reviewed were:

  • Did women benefit equally from management strategies in place in a Swiss hospital setting to reduce the time between calling for help and receiving care, and are there gender differences in factors determining delays?
  • Were there gender disparities in prehospital management of U.S. patients experiencing chest pain (CP) or out-of-hospital cardiac arrest (OHCA)?

Synopsis and Perspective:

Swiss Study

A positive prognosis following a CVD diagnosis depends on timely detection, rapidity of treatment, and initiation of evidence-based management at the point of care. There has been an alarming rise in hospitalizations for acute coronary syndromes (ACS) in women, especially in terms of admissions of women ages 45-54, for ST-elevation MI (STEMI).

Treatment for STEMI has improved over the last decade and primary percutaneous coronary intervention (PCI) is now the standard of care for STEMI in the U.S. and Europe. But results have been conflicting regarding the efficacy of this treatment in women with STEMI.

Gender-specific trends during 2000 and 2016 were retrospectively analyzed by Matthias R. Meyer, MD, of Triemli Hospital in Zurich, and colleagues. Eligible cases were 4,360 patients (967 women; 3,393 men) with acute STEMI. The women had a mean age of 69.1 and the men had a mean age of 60.7. Three additional comparisons were made during 2000-2005, 2006-2011, and 2012-2016.

Primary endpoints were changes in patient delay (the time from symptom onset to contact with a hospital, emergency medical service, or general practitioner), and system delay (the subsequent time until reopening of the vessel). In-hospital mortality served as the secondary endpoint.

While both women and men experienced patient delays during the study period, female gender was independently associated with greater patient delay (P=0.02 vs men). This accounted for a 12% greater total ischemic time among women during 2012-2016 (median 215 vs 192 minutes, P<0.001 vs men). Comparing snapshots across the trial life cycle (2012-2016 vs 2000-2005) showed a trend toward system delay declines of 25 minutes for men and 18 minutes for women (P<0.0001 for trend, no significance in terms of gender difference). Age and Killip class ≥3, rather than gender or delays, were independently associated with death.

Disease presentation for males included total occlusion of the culprit artery, stent thrombosis, and a Killip class ≥3. In addition, presentation during off-hours predicted delays in men, but not in women. After correcting for numerous factors, Meyer and colleagues concluded that delays were not associated with in-hospital deaths.

“As expected, the acute complications of a heart attack, rather than delays, drive in-hospital mortality. But we do know from previous studies that delays predict long-term mortality,” Meyer noted to Cardiology News. Interestingly, women waited 37 minutes longer than men to contact medical services.

Because of the observational study design, any attempt to infer cause-and-effect relationships should be made with caution, according to the authors.

U.S. study

Using the National Emergency Medical Services Information System (NEMSIS), Janet F. Lewis, MD, of the George Washington University School of Medicine in Washington D.C., and colleagues assessed whether gender disparities existed in the out-of-hospital management of adults, ages ≥40, who accessed the 9-1-1 EMS system for CP or OHCA. More than 2 million cases were evaluated for CP by 63,305 EMS agencies and 284,000 OHCA cases were treated by 38,074 EMS agencies.

The researchers found that the proportion of women with CP receiving recommended treatment was lower versus men. Women were significantly less likely to be transported with lights and sirens than men (-4.6%, 95% CI -8.7% to -0.5%). While 90% of OHCA cases were resuscitated, women were significantly less likely to be resuscitated than men (-1.3%, 95% CI -2.4% to -0.2%).

Many prior reports have shown gender disparities in hospital or post-hospital care, noted Rachel Bond, MD, of Northwell Health in New York City, who was not involved in the study.

With this study, “we are now targeting a new subset of healthcare workers even before the patient presents to the hospital,” Bond said to MedPage Today. “This can be ground-breaking as we know when it comes to acute coronary syndrome ‘time is muscle’ and the sooner appropriate, guideline-directed medical therapy is provided, the better the clinical outcomes.”

“Gender disparities in cardiovascular care exist at every level of the healthcare chain and undoubtedly contribute to differences in outcomes,” agreed Karol Watson, MD, PhD, of the University of California Los Angeles.

Commenting on the limitations of the U.S. study, Watson noted that the findings were based on “data from the largest EMS registry in the United States, but it is only one. Documentation for this registry is entirely voluntary and subject to reporting error. In addition, this paper looked at chest pain but not other anginal symptoms that are prominent in women like shortness of breath.”

Source References: Eur Heart J Acute Cardiovasc Care, Nov. 8, 2018; DOI: 10.1177/2048872618810410; and Women’s Health Issues 2018; DOI: 10.1016/j.whi.2018.10.007

Study Highlights: Explanation of Findings

Swiss Study

As would be expected, advanced heart failure (Killip class ≥3) and age, but not gender or delays, were independently associated with hospital mortality. Meyer and colleagues attributed a longer STEMI-related ischemic time in women versus men to persistently greater patient delays. The authors proposed that shorter patient delays and total ischemic time in men versus women, may be due to the fact that women may not recognize symptoms as a condition necessitating treatment. An alternative explanation is that the pathophysiology of STEMI may differ between the genders in that women more often have single-vessel disease and plaque erosions, may be older, and have more cardiovascular risk factors than men.

U.S. Study

Low rates of administration of evidence-based therapies were observed in a large population of women and men with CP and OHCA who were treated by more than 65,000 EMS agencies. “EMS personnel administered recommended tests and medications to fewer than one-half of the 2.4 million EMS activations for CP,” according to the authors.

They hypothesized that there may be an underappreciation of women’s heart disease risk, especially since differences for the genders were larger for individuals ages <65. This result is in line with a separate study, which showed that, among adults (ages 18-55) hospitalized for an AMI, women with a risk profile similar to that of men reported that they were told less often that they were at risk of heart disease.

Both studies add to a larger picture of evidence-based management that, until recently, did not take into account sociodemographic and gender differences (symptoms in women differ from symptoms in men). But tools such as the Women Acute Myocardial Infarction In-Hospital Mortality Risk Score (WAMI) can aid in predicting the in-hospital mortality of women. It is also worth noting that some women with classic symptoms of blocked vessels — chest pain, shortness of breath, and an abnormal cardiac stress test — may have open arteries. Nevertheless, they could experience ischemia and no obstructive coronary artery disease (INOCA).

Unraveling these differences and improving system efficiencies are likely to aid the medical profession in closing a perceived gender treatment gap.

Original story for MedPage Today by Ashley Lyles


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