The Most Common Cardiac Procedure: But Is It Safe for Women?

by: Natalia Collins, Undecided Major ‘27

“I’m still struggling with the fear it will happen again,” writes Susan Leary, after an incomplete vascularization during coronary artery bypass surgery required a second bypass procedure [1]. Known as the most common cardiac procedure, over 370,000 patients undergo coronary artery bypass surgery in a given year in the United States. However, women face over a 22.9% risk for postoperative mortality and morbidity after bypass surgery, compared to a 16.7% risk for men [2]. Coronary artery bypass surgery (CABG) is a well-understood procedure, but differences in the pathology of CABG between men and women are not well-studied, as clinical studies on CABG are performed primarily on men. The underrepresentation of women in studies on procedures like CABG points to critical gender disparities in clinical trials and in its informing of patient treatments. 

For Susan Leary, a retired New York City teacher, her CABG procedure was expected to be routine. But after an incomplete vascularization, she now has to undergo another bypass surgery [1]. Ms. Learly, a few years prior, had a procedure to shrink her varicose veins in her leg and had inadequate vessels for coronary grafting. Unknown to her doctors that she would need these veins for a cardiac procedure in the future, she had to undergo a stent procedure for her third artery after a double bypass was performed as opposed to the necessary triple bypass. Women often require CABG at later ages as opposed to men, and ill preparation can lead to cardiac readmissions and additional procedures. For Ms. Learly, the postoperative complications have caused depression and anxiety out of fear of further complications [1]. 

To address these gender discrepancies, a 2023 study in the Journal of American Medical Association investigated the postoperative outcomes of women undergoing CABG, as compared to men. Through examination of complications and mortality rates for women over a 9-year period, the study found an increased risk of a number of major complications, including myocardial infarction, kidney failure, sternal wound infections and stroke [2]. Adverse complications lead to greater rates of cardiac readmission, prolonged ventilator use, and long-term cardiac treatments [3]. Observed mortality rates following CABG had significant differences between genders: women face a 2.8% mortality rate, while men face a 1.7% mortality rate [2]. Despite these drastic variations in postoperative effects, the procedure selection and revascularization strategy remains uniform for both men and women, and treatment evaluation does not consider physiological differences across genders [4]. 

Anatomical and physiological differences between men and women are understudied, especially as they relate to treatments for CABG, causing postoperative complications unique to female patients. Women have smaller coronary arteries, along with a greater risk of heart failure from preserved ejection fraction caused by higher pressure in the left ventricle [3]. Hormonal differences in women are under examined, and estrogen withdrawal post-menopause may increase postsurgical complication rates [4]. Comorbidity factors like diabetes, obesity, smoking, and chronic kidney disease are more common among women undergoing CABG and can increase the risk of complications like myocardial infarction [4]. An understanding of the variations in pathophysiology between men and women undergoing CABG is required to create diagnostic and treatment procedures properly tailored to gender-based differences. 

Given the variations in physiology between genders, Doctor Mario Gaudino of Weill Cornell Medicine, with a team of researchers, is examining the discrepancies in postoperative outcomes of CABG [5]. The clinical trial compares the operative outcomes of multiple arterial grafting to single arterial grafting in an examination of female-only trial patients, Ms. Leary being one of 2000 women participating in the trial. By investigating the occurrence of adverse cardiac events, including death, stroke, myocardial infarction and revascularization, researchers hope to determine the CABG treatment best suited to female physiology. [6]. Dr. Gaudino emphasizes the importance of performing trials exclusive to female patients to adjust for differences in age and other gender-related health factors in CABG procedures [5]. 

Increased rates of postoperative morbidity in women point to a broader underrepresentation that exists in clinical trials and surgical techniques. Generalized treatments for both men and women create disparities in operative outcomes. Procedures must be tailored to account for gender-related physiological differences. For patients like Ms. Leary, the lack of consideration for variations in operative outcomes poses significant risks for both physical and mental well-being. Advancements in surgical procedures must consider essential differences that exist among underrepresented populations, and future work must be done to account for these differences and strive for equity in the healthcare space. 

References

1. Span, Paula. “The Heart Surgery That Isn’t as Safe for Older Women.” The New York Times, 20 Jan. 2024, www.nytimes.com/2024/01/20/health/heart-bypass-women.html.

2. Gaudino, Mario, et al. “Operative Outcomes of Women Undergoing Coronary Artery Bypass Surgery in the US, 2011 to 2020.” the Journal of the American Medical Association, vol. 158, no. 5, 1 May 2023, pp. 494–494, https://doi.org/10.1001/jamasurg.2022.8156. Accessed 17 July 2023.

3. Robina Matyal, et al. “Update: Gender Differences in CABG Outcomes—Have We Bridged the Gap?” PLOS ONE, vol. 16, no. 9, 15 Sept. 2021, pp. e0255170–e0255170, www.ncbi.nlm.nih.gov/pmc/articles/PMC8443029/, https://doi.org/10.1371/journal.pone.0255170. Accessed 8 Nov. 2023.

4. Kawamoto, Kris R., et al. “Acute Coronary Syndromes: Differences in Men and Women.” Current Atherosclerosis Reports, vol. 18, no. 12, 2 Nov. 2016, link.springer.com/article/10.1007/s11883-016-0629-7, https://doi.org/10.1007/s11883-016-0629-7.

5. “Nationwide Study Finds That Women Have Greater Risk of Mortality than Men after Coronary Artery Bypass Surgery.” WCM Newsroom, 6 Mar. 2023, news.weill.cornell.edu/news/2023/03/nationwide-study-finds-that-women-have-greater-risk-of-mortality-than-men-after.

6. Weill Medical College of Cornell University. “Comparison of the Outcomes of Single vs Multiple Arterial Grafts in Women (ROMA: Women).” Clinicaltrials.gov, 20 Dec. 2023, clinicaltrials.gov/study/NCT04124120.