Inspired by the pioneering French physician, Professor C Noel Bairey Merz (Cedars-Sinai Smidt Heart Institute - Los Angeles, USA) will discuss the technological advances that have furthered our understanding of CVD in women in her ESC Rene Laennec Lecture in Clinical Cardiology.
“The emergence of US sex-stratified data in the 1980s showed that while CVD mortality was declining in men, there were no such reductions in women. This observation prompted the US National Heart, Lung, and Blood Institute to sponsor the Women's Ischemia Syndrome Evaluation (WISE) study to address ischaemic heart disease (IHD) recognition and diagnosis specifically in women. In the almost 30 years I have been honoured to chair the WISE study, we have made major insights using technological advancements to explore what couldn’t be seen before.
When the WISE study began, existing diagnostic techniques – including angiography – were geared towards detecting obstructive IHD, the predominant form of disease in men. With the advent of doppler catheters and assessment of blood flow, it was discovered that while arteries are often not blocked in women, there is frequently a reduction in flow in the small vessels [1]. This was a turning point as non-obstructive disease was previously not considered to be clinically problematic and consequently had no management recommendations. From then on, coronary microvascular dysfunction became recognised as a common cause of female IHD. Around the same time, the use of intravascular ultrasound catheters revealed further sex differences. In particular, it was noted that atherosclerotic plaques are often hidden in the artery wall in women due to positive remodelling, preserving lumen size – a finding that could not be observed using traditional angiography [2].
Other technological innovations – magnetic resonance imaging (MRI) and spectroscopy (MRS) – then provided a new way to assess blood flow and to characterise cardiac muscle without the ionising radiation risks associated with catheterisation. It was MRS that revealed coronary microvascular dysfunction was associated with myocardial ischaemia [3]. We were also able to show that small vessel-mediated ischaemia was responsible for angina symptoms [4] and are exploring relationships to metabolic derangement, a contributor to heart failure with preserved ejection fraction (HFpEF).
Looking ahead, we need to harness cardiac MRI and MRS to fill other gaps in our knowledge of the pathophysiology of CVD in women, including the mechanisms responsible for heart, brain and peripheral microvascular disease as well as HFpEF. These tools, and technology advances to come, will allow us to learn more about metabolic dysregulation, whether due to diabetes, arterial fat distribution, impaired oxygen delivery or other abnormalities, so we can develop new treatment targets to reduce CVD in women and men.”
