Carotid Intima-Media Thickness and Sheehan’s Syndrome

Dear Sir, Agrawal et al.[1] published an article in the recent issue of the Indian Journal of Endocrinology and Metabolism titled, ‘Cardiovascular Risk Factors in Sheehan’s Syndrome: A Case-Control Study.’ Sheehan’s Syndrome (SS) or postpartum hypopituitarism results from severe postpartum haemorrhage causing pituitary necrosis and consequently hypopituitarism.[1] Associated conditions are obesity, dyslipidaemia and insulin resistance.[1] Agrawal et al.’s[1] study aimed to investigate this poorly understood association between these conditions and SS. In their cross-sectional case–control study, 45 patients with SS (age: 48.1 ± 10 years) and age-, gender- and body mass index (BMI)-matched 45 healthy controls from the community were included.[1] As a surrogate marker for pre-clinical atherosclerosis, carotid intima-media thickness (cIMT), was used.[1] Ultrasound examination to measure cIMT was performed for all subjects.[1] The authors found that cIMT was significantly increased in SS as compared to controls (0.62 ± 0.11 vs. 0.57 ± 0.14, P < 0.05).[1] The authors concluded, ‘SS patients on standard replacement therapy except GH replacement have increased cardiovascular risk,… and may lead to increased mortality’.[1] There are some comments needed to evaluate the results and conclusions of this study in a more balanced way. The cIMT was measured at the common carotid artery (CCA) in proximity to the bifurcation.[1] The average of three measurements was taken during the end of the diastole on each side, and the mean of both sides, the left and right, was taken for an overall cIMT.[1] However, it remains unclear from which CCA wall the measurements occurred. As there is no uniformity in cIMT measurement, the procedure and reason for the adopted measurement protocol need detailing. There are two main lines of recommendation/thoughts, a) a single-site cIMT measurement at the far CCA wall in a plaque-free segment in the proximity of the bifurcation[2] or b) a multiple-site cIMT measurement that includes several internal carotid artery (CA) sections, for example, far/near walls of CCA, bifurcation and internal CA.[3,4] One major reason presented for far wall cIMT measures is the higher spatial resolution of the far wall.[2] However, Bots et al.[3] have already specified in 2003, ‘The reproducibility of near wall cIMT measurements is similar to that reported for far wall cIMT measurements. Combining information on near wall and far wall common cIMT into 1 IMT estimate (average of four sites) provided the strongest association with cardiovascular disease in this study’. A one-site measurement as performed by Agrawal et al.[1] may coincide with a normal CA segment, but still be within an atherosclerotic altered vessel, misclassifying subjects as normal. Combining different CA sites for cIMT determination may reflect/capture, therefore, the asymmetrical presentation of atherosclerosis and therefore also the cIMT estimate in a more accurate way.[3,4] Agrawal et al.[1] also did not specify which cIMT value they used to define pathological cIMT; considering that there is no agreement on this critical aspect within the neuro-vascular community, authors need to explain which cIMT values are used as references to define thresholds.[5] To sum up: The cIMT data in Agarwal et al.’s study can still be considered within the normal range (<0.70 mm) and have no diagnostic nor prognostic value. In light of these methodological considerations and the critical lack of detailed reporting, the conclusions of this study, based on the cIMT data,[1] should be considered with due caution. Financial support and sponsorship Nil. Conflicts of interest There are no conflicts of interest.