Prognostic significance of diabetes in acute myocardial infarction. Are the differences linked to female gender?

Abstract

Sir at variance with the Diabetes Mellitus and Acute We read with interest the recent paper by GalceraMyocardial Infarction (DIAGAMI) Study [10,11] Tomas et al. [1] in The Journal, which found that where gender was not an independent predictor of diabetes mellitus was not an independent predictor of mortality. mortality post-myocardial infarction. Interestingly, Such variation in outcome following myocardial female gender was associated with an increased risk infarction may be due, in part, to gender-related of adverse events following acute myocardial infarcdifferences in the interaction between the left ventrition but only in the diabetic population. cle and the arterial tree (ventriculo-vascular couThe link between diabetes mellitus and carpling). An important determinant of which is the diovascular disease is well described [2], and previshape of the central pressure waveform. A recent ous studies have demonstrated a worse prognosis for study by Hayward and Kelly demonstrated differdiabetics post-myocardial infarction [3]. However, ences in the aortic pressure waveform between men the effect of gender on cardiovascular risk, and the and women [12]. Augmentation index (AIx) – a interaction between gender and diabetes mellitus is measure of the degree to which systolic pressure is complex. Women have a lower incidence of isaugmented by wave reflection – was consistently chaemic heart disease than men until they reach the greater in women compared with men throughout all menopause [4] or develop diabetes [5]. However, the decades of life [12]. This was due mainly to shorter mechanisms involved in the protective effect of stature and a different ejection pattern in women, female gender remain poorly understood, although resulting in earlier return of the reflected pressure oestrogens may clearly be important. This is despite a wave to the ascending aorta. Increased augmentation greater age-related rise in left ventricular mass, an not only raises central systolic pressure and left important and independent predictor of all cause ventricular workload, which may explain why healthy mortality, amongst women compared with men [6]. women have a greater left ventricular mass compared A number of studies have investigated the effect of with men, but also reduces the subendocardial viabiligender on prognosis following myocardial infarction. ty index [12]. This may account for the correlation In non-diabetics, at least, the results appear to be between short stature and the risk of coronary heart consistent, with higher rates of heart failure postdisease and stroke in both men [13] and women [14]. infarction [7,8], and a significantly greater risk of Moreover, since women are, in general, shorter than ventricular rupture [9] amongst women. Within the men, height may be a potential confounding variable diabetic population, the results are less consistent. in studies assessing the effect of gender on carIndeed, the findings from Galcera-Tomas et al. [1] are diovascular risk. Unfortunately, although body mass