Operative outcomes in women undergoing coronary artery bypass grafting (CABG) surgery have not improved in the period from 2011 to 2020, according to a newly released study.  For mortality, being female was associated with a 28% to 41% higher risk depending on the year of surgery during the covered period.

The study results confirm the findings of studies based on surgery data from prior decades.  Women have long tended to fare worse than men after CABG, and this cohort study of more than 1 million patients was performed to determine if any improvement in this outcome had occurred over a decade.

Published last month in JAMA Surgery, the study used the Adult Cardiac Surgery Database, maintained by the Society for Thoracic Surgeons, to analyze 1,297,204 bypass surgeries, of which 317,716 (24.5%) were performed in women.

The ‘why’ of women’s worse CABG outcomes

Each year in the United States, at least 240,000 CABG surgeries are performed, according to statistics published by the American Heart Association (AHA).  Over the past few decades, advances in surgical techniques and overall care have brought improved outcomes from these surgeries.

However, since the 1990s, studies of these surgeries have revealed evidence that, compared with male patients, female patients tend to experience worse outcomes.

Women have their own unique set of risk factors.  First, female bypass surgery patients are older on average and more likely to experience co-morbidities such as diabetes, have relatively high testosterone levels prior to menopause, increased hypertension during menopause, and higher levels of stress and depression.  Yet even when researchers have adjusted their analyses to take these factors into account, women still appear to experience worse outcomes on average.

Further, females are also less likely to receive the surgery.  Research presented at the 2021 Society of Thoracic Surgeons (STS) 57th Annual Meeting found that women with coronary artery disease were significantly less likely to undergo CABG than their male counterparts.  Jawitz and colleagues from Duke University and The Johns Hopkins University School of Medicine in Baltimore, Maryland, analyzed the data of more than 1.2 million patients from an STS database—the world’s largest cardiac surgical database—and found that women were 14% to 22% less likely to undergo guideline-recommended revascularization procedures—all of which are associated with improved outcomes (Ann Thorac Surg. 2022).

In addition, Jawitz elucidated, women tend to have a longer time from cardiovascular disease symptom onset to diagnosis, and from diagnosis to medical intervention.  Each of these delays allows the disease to worsen over time, increasing the risk for poor surgical outcomes.

No female mortality, morbidity change in a decade

In the most recent JAMA Surgery study, the primary outcome measures were “operative mortality”—death during surgery or within the 30 days following surgery—and a composite measure defined as operative mortality or a major post-operative complication, such as stroke or kidney failure.  The research team from Weill Cornell Medicine and New York-Presbyterian/Weill Cornell Medical Center found that women had a higher operative mortality and incidence of the composite post-operative complications compared with men.

The attributable risk of female sex for operative mortality varied from 1.28 in 2011 to 1.41 in 2020, with no significant change over the study period, and the attributable risk for the composite of operative mortality and morbidity was 1.08 in both 2011 and 2020, with no significant change over the study period, the researchers reported.

The analysis found the rate of operative mortality following CABG was 2.8% for women, compared with 1.7% for men, and the rate of operative mortality and morbidity among women was 22.9% compared with 16.7% among men.

‘We’re clearly missing something here’

Further investigation into the determinants of operative outcomes in women is “urgently needed,” the authors of the most recent study concluded.

“We’re clearly missing something here,” stated Mario Gaudino, MD, PhD, Stephen and Suzanne Weiss Professor in Cardiothoracic Surgery at Weill Cornell Medicine and cardiothoracic surgeon at New York-Presbyterian/Weill Cornell Medical Center, lead investigator for the study.

“That means we need more data on women—data on the physiology of their coronary artery disease and how it tends to differ from men’s, and data on their responses to different treatments and surgical techniques,” he stated in a communique from New York-Presbyterian Hospital which accompanied release of the study data.

As next steps, he and his colleagues are planning a clinical trial exclusively in female patients to ascertain whether the use of multiple coronary artery bypasses during surgery improves outcomes over single-artery bypasses.

Link to access the full study, “Operative Outcomes of Women Undergoing Coronary Artery Bypass Surgery in the US, 2011 to 2020,” here.

Clinicians’ Bonus:  More To Know

Resources for you and your patients

 For You

Women’s awareness that heart disease is the leading cause of death among women fell over 21% from 2009 to 2019 according to the latest national AHA Survey of Women’s Cardiovascular Disease Awareness.  This concerning decline was observed in women of all ages except those 65 years of age and older, across all racial/ethnic groups, and was greatest among women under 34 years of age.  Be sure to read the full findings—part of the AHA’s escalation of efforts to educate women through awareness campaigns, cardiovascular screening, and counseling.

For Your Patients

The AHA offers a series of brief, easy to read, and easy to follow downloadable Q&A information sheets for your patients called Answers by Heart.  The series provides information about a range of tests and treatments for cardiovascular conditions as well as tips on disease management, recovery, and medication.  Topics include Cardiovascular Conditions, Treatments and Tests, and Lifestyle and Risk Reduction.  Find the no-cost series, many of which many are available in Spanish, here.

The contents of this feature are not provided or reviewed by NPWH.