Do clinically relevant differences in outcomes exist between women and men undergoing treatment for cardiovascular disease?

Buchanan, Gill Louise

Abstract

Introduction
Throughout my own clinical practice, I became aware that differences may exist between men and women in the decisions for treatment and the outcomes after intervention for cardiovascular disease. Clinical trials have corroborated this with women typically presenting at an older age and studies have suggested there are innate differences between the sexes with women believed to have worse outcomes than men. However, historically women have been poorly represented in clinical trials, which has led to biased result interpretation, despite cardiovascular disease remaining the leading cause of death in women. Therefore, extrapolation of results to women may lead to differences in expected outcomes.

The aim of this thesis was to explore the question: ‘Do outcomes differ between women and men in the treatment of cardiovascular disease?’

Methods
The over-arching research question was addressed by integrating results from 5 individual datasets. Following the literature review, the areas identified for investigation were: 1) The role of female sex in the treatment of the left main coronary artery; 2) Bleeding risk in women undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction; 3) Does sex play a role in the activated clotting time during angioplasty; 4) The role of sex on outcomes following transcatheter aortic valve implantation; and 5) Sex differences in the perceived intensity of symptoms in patients with aortic stenosis.

Each of these studies involved observational data from real world patients and allowed for assessment of matched populations to allow for a comparison when appropriate. The datasets were then analysed utilising the constructivist paradigm to identify themes that contribute to robust and generalisable new knowledge in this field.

Results
The treatment of the complex left main coronary artery is first addressed and demonstrates no differences between the sexes in those undergoing percutaneous coronary intervention, however there was an advantage in women undergoing coronary artery bypass grafting. In patients presenting with ST-elevation myocardial infarction, women have more episodes of bleeding, however despite this have the same good outcome as men in hospital and therefore require the same access to treatment. The anti-coagulation regime during percutaneous coronary intervention is then considered and demonstrates that for a similar dose of unfractionated heparin, women are more likely to have a very high activated clotting time which may explain the increased risk of bleeding in the prior chapter.

In the assessment of aortic stenosis, in symptomatic patients undergoing transcatheter aortic valve implantation, women again appear to have an advantage over men, with male sex a predictor of mortality at long-term follow-up. However, finally addressing the symptomatology of aortic stenosis, there were no differences between sexes in the symptoms of breathlessness or in NT-pro-BNP levels.

Conclusions
The analysis demonstrated that despite an older presentation in women who underwent treatment, women can do as well as men (in coronary artery disease) or even fare better (for transcatheter aortic valve implantation) despite more bleeding and vascular complications. This may impact significantly regarding the multi-disciplinary discussion regarding intervention for these patients and needs to be considered by the clinicians involved in the treatment of cardiovascular disease.

The limitations of the studies are that the data are non-randomised and in 2 of the data sets there are small sample sizes. Additionally, there are the difficulties associated with the analysis of mixed methods research in analysing quantitative data qualitatively.

In summary, when determining if patient sex should be a factor when deciding upon the management of acquired cardiovascular disease, the triangulation of data from across a number of data sets in this thesis suggests that sex should not be the primary consideration. Further research is needed to refine clinical understanding of which factors should be taken into account.

Citation

Buchanan, G. L. (2018). Do clinically relevant differences in outcomes exist between women and men undergoing treatment for cardiovascular disease?. (Thesis). Hull York Medical School, the University of Hull and the University of York. Retrieved from https://hull-repository.worktribe.com/output/4222132

• Thesis Type: Thesis
• Deposit Date: Feb 17, 2020
• Publicly Available Date: Feb 23, 2023
• Keywords: Medicine
• Public URL: https://hull-repository.worktribe.com/output/4222132
• Additional Information: Hull York Medical School, The University of Hull and The University of York
• Award Date: Apr 1, 2018