Novel advanced cardiovascular magnetic resonance imaging study in women with gestational diabetes mellitus and preeclampsia

Pregnant women represent an under-investigated population in clinical research and the mechanisms of long-term cardiovascular complications in women with obstetric complications remain to be elucidated. This is the basis which stemmed our interest in conducting our research in pregnant women with gestational diabetes mellitus (GDM) and preeclampsia(pE). A third of parous women experience adverse pregnancy outcomes; an increased risk of heart failure, stroke and ischemic heart disease. GDM and pE are the leading obstetric complications of pregnancy. Both are associated with a substantial increase in the risk of long-term cardiovascular disease. The aims of my longitudinal cohort study were to assess maternal cardiac alterations during the third trimester of pregnancy and their recovery twelve-months post-partum in women with GDM (n=30) or pE (n=22) compared to women with healthy pregnancies (HP)(n=38). Phosphorus-magnetic resonance spectroscopy (31 P-MRS) and cardiovascular magnetic resonance imaging (CMR) were used to define myocardial phosphocreatine to ATP ratio (PCr/ATP), tissue characteristics, left ventricular (LV) volumes, mass, ejection fraction (EF), global longitudinal shortening (GLS), and diastolic function (mitral in-flow E/A ratio). Participants were monitored to birth, baby birth weights were recorded, placental tissue histology was assessed. Investigations were repeated 12-months postpartum to monitor cardiac changes. With obesity as a major and common risk factor for both GDM and pE, ten overweight and ten normal-weight nulliparous women were recruited as non-pregnant control groups. These studies have demonstrated that despite distinct etiologies, women with GDM and pE exhibit a similar myocardial phenotype during and after pregnancy with persistent subtle abnormalities in myocardial PCr/ATP ratio, LV mass and GLS compared to women with HP during pregnancy and twelve months’ postpartum assessments. Women with GDM and pE show similar myocardial alterations to nulliparous women with obesity, suggesting that the maternal myocardial changes are predominantly driven by obesity-associated metabolic dysfunction. In summary, the work in this thesis demonstrates the role of CMR and MRS in elucidating the cardiac structural, functional and energetic abnormalities in pregnancies complicated with gestational diabetes and preeclampsia. Most importantly, this work highlights that the persistent myocardial changes seen in women with GDM and pE at 12 months are mainly driven by obesity-associated metabolic dysfunction. With obesity becoming a huge worldwide health burden, it is very crucial to create societal awareness to support patients for a healthier lifestyle. This can be implemented through evidence based medicine and population based policies. Further research can be conducted to identify patients at risk and implement lifestyle interventions early to avoid long term complications to both the mother and fetus.