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Objective Somatostatin receptor ligands have come to play a pivotal role in the treatment of both ACTH- and GH-secreting pituitary adenomas. Clinical efficacy averages 30-50%, thus a considerable number of patients with Cushing's disease or acromegaly remain unresponsive to this therapeutic approach. HTL0030310 is a new somatostatin receptor ligand selective for subtype 5 over subtype 2, thus with a different receptor profile compared to clinical somatostatin receptor ligands. Design Assessment of the effect of HTL0030310 on hormone secretion in human ACTH- and GH-secreting pituitary adenomas in vitro. Methods Primary cultures from 3 ACTH-secreting and 5 GH-secreting pituitary adenomas were treated with 1, 10 and 100 nM HTL0030310 alone or with 10 nM CRH or GHRH, respectively. Parallel incubations with 10 nM pasireotide were also carried out. ACTH and GH secretion were assessed after 4 and 24 hour incubation; SSTR2, SSTR3, SSTR5 , GH and POMC expression were evaluated after 24 hours. Results HTL0030310 reduced unchallenged ACTH and POMC levels up to 50% in 2 ACTH-secreting adenomas and blunted CRH-stimulated ACTH/ POMC by 20-70% in all 3 specimens. A reduction in spontaneous GH secretion was observed in 4 GH-secreting adenomas and in 2 specimens during GHRH co-incubation. SSTR s expression was detected in all specimens. Conclusions This first study on a novel somatostatin receptor 5-preferring ligand indicates that HTL0030310 can inhibit hormonal secretion in human ACTH- and GH-secreting pituitary adenomas. These findings suggest a potential new avenue for somatostatin ligands in the treatment of Cushing's disease and acromegaly. [ABSTRACT FROM AUTHOR]

Context: Diagnostic accuracy of testing currently used for the differential diagnosis of Cushing disease (CD) vs ectopic adrenocorticotropic hormone secretion (EAS) is difficult to interpret. Objective: The present study aimed to identify and evaluate the diagnostic accuracy of the corticotropin-releasing hormone (CRH) test, the desmopressin test, and the high-dose dexamethasone suppression test (HDDST) when used to establish a CD or EAS diagnosis. Methods: This study is a systematic review of the literature and meta-analysis. MEDLINE, OVID, and Web of Science databases were searched for articles published between 1990 and 2021. Articles included described at least 1 test(s) (CRH, desmopressin, or HDDST) and the diagnostic reference standard(s) (histopathology, petrosal sinus sampling, surgical remission, imaging, and long-term follow-up) used to establish a CD or EAS diagnosis. Results: Sixty-two studies were included: 43 reported the use of the HDDST; 32, the CRH test; and the 21, the desmopressin test. The CRH test was found to have the highest sensitivity in detecting CD (ACTH 86.9%, 95% CI 82.1-90.6, cortisol 86.2%, 95% CI 78.3-91.5) and the highest specificity in detecting EAS (ACTH 93.9%, 95% CI 87-98.3, cortisol 89.4%, 95% CI 82.8-93.7). This resulted in a high diagnostic odds ratio (58, 95% CI 43.25-77.47), large area under the curve, and a receiver operating characteristic of 0.934. The diagnostic accuracy of the HDDST and desmopressin test was lower than that of the CRH test. Conclusion: The meta-analysis indicates that a patient with a positive ACTH response after a CRH test is highly likely to have CD. Further studies analyzing role of dynamic testing in addition to imaging are needed. [ABSTRACT FROM AUTHOR]

Introduction: Pasireotide (PAS) is a novel somatostatin receptor ligands (SRL), used in controlling hormonal hypersecretion in both acromegaly and Cushing's Disease (CD). In previous studies and meta-analysis, first-generation SRLs were reported to be able to induce significant tumor shrinkage only in somatotroph adenomas. This systematic review and meta-analysis aim to summarize the effect of PAS on the shrinkage of the pituitary adenomas in patients with acromegaly or CD. Materials and methods: We searched the Medline database for original studies in patients with acromegaly or CD receiving PAS as monotherapy, that assessed the proportion of significant tumor shrinkage in their series. After data extraction and analysis, a random-effect model was used to estimate pooled effects. Quality assessment was performed with a modified Joanna Briggs's Institute tool and the risk of publication bias was addressed through Egger's regression and the three-parameter selection model. Results: The electronic search identified 179 and 122 articles respectively for acromegaly and CD. After study selection, six studies considering patients with acromegaly and three with CD fulfilled the eligibility criteria. Overall, 37.7% (95%CI: [18.7%; 61.5%]) of acromegalic patients and 41.2% (95%CI: [22.9%; 62.3%]) of CD patients achieved significant tumor shrinkage. We identified high heterogeneity, especially in acromegaly (I2 of 90% for acromegaly and 47% for CD), according to the low number of studies included. Discussion: PAS treatment is effective in reducing tumor size, especially in acromegalic patients. This result strengthens the role of PAS treatment in pituitary adenomas, particularly in those with an invasive behavior, with progressive growth and/or extrasellar extension, with a low likelihood of surgical gross-total removal, or with large postoperative residual tissue. [ABSTRACT FROM AUTHOR]

Adrenocorticotropic Hormone (ACTH)-secreting pituitary adenomas are rare tumors characterized by autonomous ACTH secretion with a consequent increase in circulating cortisol levels. The resulting clinical picture is called Cushing's disease (CD), a severe condition burdened with high morbidity and mortality. Apart from increased cortisol levels, CD patients exhibit a partial resistance to the negative glucocorticoid (GC) feedback, which is of paramount clinical utility, as the lack of suppression after dexamethasone administration is one of the mainstays for the differential diagnosis of CD. Since the glucocorticoid receptor (GR) is the main regulator of negative feedback of the hypothalamic–pituitary–adrenal axis in normal conditions, its implication in the pathophysiology of ACTH-secreting pituitary tumors is highly plausible. In this paper, we review GR function and structure and the mechanisms of GC resistance in ACTH-secreting pituitary tumors and assess the effects of the available medical therapies targeting GR on tumor growth. [ABSTRACT FROM AUTHOR]

Cushing's disease (CD) causes diabetes mellitus (DM) through different mechanisms in a significant proportion of patients. Glucose metabolism has rarely been assessed with appropriate testing in CD; we aimed to evaluate hormonal response to a mixed meal tolerance test (MMTT) in CD patients and analyzed the effect of pasireotide (PAS) on glucose homeostasis. To assess gastro-entero-pancreatic hormones response in diabetic (DM+) and non-diabetic (DM–) patients, 26 patients with CD underwent an MMTT. Ten patients were submitted to a second MMTT after two months of PAS 600 µg twice daily. The DM+ group had significantly higher BMI, waist circumference, glycemia, HbA1c, ACTH levels and insulin resistance indexes than DM− (p < 0.05). Moreover, DM+ patients exhibited increased C-peptide (p = 0.004) and glucose area under the curve (AUC) (p = 0.021) during MMTT, with a blunted insulinotropic peptide (GIP) response (p = 0.035). Glucagon levels were similar in both groups, showing a quick rise after meals. No difference in estimated insulin secretion and insulin:glucagon ratio was found. After two months, PAS induced an increase in both fasting glycemia and HbA1c compared to baseline (p < 0.05). However, this glucose trend after meal did not worsen despite the blunted insulin and C-peptide response to MMTT. After PAS treatment, patients exhibited reduced insulin secretion (p = 0.005) and resistance (p = 0.007) indexes. Conversely, glucagon did not change with a consequent impairment of insulin:glucagon ratio (p = 0.009). No significant differences were observed in incretins basal and meal-induced levels. Insulin resistance confirmed its pivotal role in glucocorticoid-induced DM. A blunted GIP response to MMTT in the DM+ group might suggest a potential inhibitory role of hypercortisolism on enteropancreatic axis. As expected, PAS reduced insulin secretion but also induced an improvement in insulin sensitivity as a result of cortisol reduction. No differences in incretin response to MMTT were recorded during PAS therapy. The discrepancy between insulin and glucagon trends while on PAS may be an important pathophysiological mechanism in this iatrogenic DM; hence restoring insulin:glucagon ratio by either enhancing insulin secretion or reducing glucagon tone can be a potential therapeutic target. [ABSTRACT FROM AUTHOR]

Cushing's syndrome (CS) is a rare disease caused by chronic and excessive cortisol secretion. When adrenocorticotropin hormone (ACTH) is measurable, autonomous adrenal cortisol secretion could be reasonably ruled out in a differential diagnosis of CS. ACTH-dependent CS accounts for 80%-85% of cases and involves cortisol production stimulated by uncontrolled pituitary or ectopic ACTH secretion. Pituitary adenoma is not detected in up to one-third of cases with pituitary ACTH secretion, whereas cases of CS due to ectopic ACTH secretion may be associated with either malignant neoplasia (such as small cell lung carcinoma) or less aggressive neuroendocrine tumors, exhibiting only the typical symptoms and signs of CS. Since the differential diagnosis of ACTH-dependent CS may be a challenge, many strategies have been proposed. Since none of the available tests show 100% diagnostic accuracy, a step-by-step approach combining several diagnostic tools and a multidisciplinary evaluation in a referral center is suggested. In this review, we present a clinical case to demonstrate the diagnostic work-up of ACTH-dependent CS. We describe the most commonly used dynamic tests, as well as the applications of conventional or nuclear imaging and invasive procedures. [ABSTRACT FROM AUTHOR]

Introduction: Italy, since the end of February 2020, is experiencing the corona virus disease 2019 (COVID-19) pandemic that may present as an acute respiratory infection. We report on COVID-19 pneumonia in the context of a complex case of Cushing's disease (CD). Case Report: A 67-year-old man with CD, who was admitted to our hospital, presented with signs and symptoms of adrenal insufficiency with persistent hypotension and glycemia toward the lower limits. We progressively withdrew almost all treatments for diabetes and CD (pasireotide and metyrapone), and i.v. hydrocortisone was necessary. A tendency to hyperkalemia was probably associated to enoxaparin. We summarized the many possible interactions between medications of Cushing's syndrome (CS) and COVID-19. Conclusion: Adrenal insufficiency might be a clinical challenge that needs a prompt treatment also in CS patients during COVID-19 infection. We should consider the possibility to titrate or temporary halt medical therapies of CS in the context of COVID-19 infection. Unexpected hyperkalemia in CS patients under treatment with heparin might be the signal of aldosterone suppression. [ABSTRACT FROM AUTHOR]

Objective: Germline ARMC5 mutations are considered to be the main genetic cause of primary macronodular adrenal hyperplasia (PMAH). PMAH is associated with high variability of cortisol secretion caused from subclinical hypercortisolism to overt Cushing's syndrome (CS), in general due to bilateral adrenal nodules and rarely could also be due to non-synchronic unilateral adrenal nodules. The frequency of adrenal incidentalomas (AI) associated with PMAH is unknown. This study evaluated germline allelic variants of ARMC5 in patients with bilateral and unilateral AI and in patients with overt CS associated with bilateral adrenal nodules. Methods: We performed a retrospective multicenter study involving 123 patients with AI (64 bilateral; 59 unilateral). We also analyzed 20 patients with ACTH pituitary independent overt CS associated with bilateral adrenal nodules. All patients underwent germline genotyping analysis of ARMC5 ; abdominal CT and were classified as normal, possible or autonomous cortisol secretion, according to the low doses of dexamethasone suppression test. Results: We identified only one pathogenic allelic variant among the patients with bilateral AI. We did not identify any pathogenic allelic variants of ARMC5 in patients with unilateral AI. Thirteen out of 20 patients (65%) with overt CS and bilateral adrenal nodules were carriers of pathogenic germline ARMC5 allelic variants, all previously described. The germline ARMC5 mutation was observed in only one patient with bilateral AI; it was associated with autonomous cortisol secretion and showed to be a familial form. Conclusion: The rarity of germline ARMC5 mutations in AI points to other molecular mechanisms involved in this common adrenal disorder and should be investigated. In contrast, patients with overt Cushing's syndrome and bilateral adrenal nodules had the presence of ARMC5 mutations that were with high prevalence and similar to the literature. Therefore, we recommend the genetic analysis of ARMC5 for patients with established Cushing's syndrome and bilateral adrenal nodules rather than patients with unilateral AI. [ABSTRACT FROM AUTHOR]

When hypertension, a pathology that is frequently found in the general population, presents in a young patient, secondary causes such as Cushing's syndrome (CS), a rare disease characterized by long-term elevated cortisol levels, should be considered. Present in ~80% of CS patients independently of their age and sex, hypertension is one of the pathology's most prevalent, alarming features. Its severity is principally associated with the duration and intensity of elevated cortisol levels. Prompt diagnosis and rapid initiation of treatment are important for reducing/delaying the consequences of hypercortisolism. Glucocorticoid excess leads to hypertension via a variety of mechanisms including mineralocorticoid mimetic activity, alterations in peripheral and renovascular resistance, and vascular remodeling. As hypertension in CS patients is caused by cortisol excess, treating the underlying pathology generally contributes to reducing blood pressure (BP) levels, although hypertension tends to persist in approximately 30% of cured patients. Surgical removal of the pituitary tumor remains the first-line treatment for both adrenocorticotropin hormone (ACTH) dependent and independent forms of the syndrome. In light of the fact that surgery is not always successful in curing the underlying disease, it is essential that other treatments be considered and prescribed as needed. This article discusses the mechanisms involved in the pathogenesis of CS and the pros and the cons of the various antihypertensive agents that are presently available to treat these patients. [ABSTRACT FROM AUTHOR]

Associated with important comorbidities that significantly reduce patients' overall wellbeing and life expectancy, Cushing's disease (CD) is the most common cause of endogenous hypercortisolism. Glucocorticoid excess can lead to diabetes, and although its prevalence is probably underestimated, up to 50% of patients with CD have varying degrees of altered glucose metabolism. Fasting glycemia may nevertheless be normal in some patients in whom glucocorticoid excess leads primarily to higher postprandial glucose levels. An oral glucose tolerance test should thus be performed in all CD patients to identify glucose metabolism abnormalities. Since diabetes mellitus (DM) is a consequence of cortisol excess, treating CD also serves to alleviate impaired glucose metabolism. Although transsphenoidal pituitary surgery remains the first-line treatment for CD, it is not always effective and other treatment strategies may be necessary. This work examines the main features of DM secondary to CD and focuses on antidiabetic drugs and how cortisol-lowering medication affects glucose metabolism. [ABSTRACT FROM AUTHOR]

Background and aim Differential diagnosis between Cushing's Disease ( CD) and Ectopic ACTH Syndrome ( EAS) may be a pitfall for endocrinologists. The increasing use in clinical practice of chromatography and mass spectrometry improves the measurement of urinary free cortisol ( UFF) and cortisone ( UFE). We have recently observed that cortisol to cortisone ratio ( FEr) was higher in a small series of EAS; in this study we collected a larger number of ACTH-dependent Cushing's Syndrome ( CS) to study the role of FEr to characterize the source of corticotropin secretion. Materials and methods High-pressure liquid chromatography with UV detection ( HPLC- UV, n=35) or liquid chromatography-tandem mass spectrometry ( LC- MS/ MS, n=72) were used to measure UFF, UFE and FEr in 83 patients with CD and 24 with EAS. Results UFF, UFE and FEr levels were higher in EAS than in CD ( UFF: 6671 vs 549 nmol/24 hours; UFE: 2069 vs 464 nmol/24 hours; FEr: 4.13 vs 0.97; all P<.001). FEr >1.15 (the best ROC-based threshold) was able to distinguish CD from EAS with 75% sensitivity ( SE) and 75% specificity ( SP), AUC 0.811; results were similar between HPLC- UV ( SE 73%, SP 79%, AUC 0.708) and LC- MS/ MS ( SE 77%, SP 73%, AUC 0.834; P=.727). The diagnostic accuracy of FEr was similar to that of CRH test or high-dose dexamethasone suppression test (respectively P=.171 and P=.683), also combined. Finally, FEr was able to increase the number of correct diagnosis in patients with discordant dynamic tests. Conclusions Urinary FEr >1.15 was able to suggest EAS, with a diagnostic accuracy similar to that of other dynamic tests proposed to study ACTH-dependent CS. [ABSTRACT FROM AUTHOR]

Patients with active Cushing's syndrome (CS) exhibit an increase of the visceral adipose tissue, increasing the risk of cardiovascular events. Until now, it is not yet clear whether remission of CS leads to a normalization of body composition, or if different strategies to control hypercortisolism could result in a different clinical outcome concerning adipose tissue distribution. Therefore, we analyzed body composition changes using dual-energy X-ray absorptiometry (DXA) in patients with CS in a prospective and controlled study. We considered 23 patients with CS, whose remission was achieved after surgery in 14 or gained with pharmacological treatment in 9 subjects. Clinical and DXA data (lean and fat mass in total body, trunk, and R1 box) were collected during active hypercortisolism and after sustained remission, defined as the normalization of both late night salivary and 24-h urinary cortisol levels, at least for 6 consecutive months. Healthy subjects, matched with CS for gender, age, and BMI, were considered as controls (n = 25). After remission of hypercortisolism, body compositions of patients were similar to matched controls; fat mass in total body ( - 7.53 %), trunk ( - 3.24 %), and R1- box ( - 12.82 %, all p < 0.01) were decreased from baseline levels. Dividing patients by type of treatment, fat mass reduction was higher in those that achieved surgical remission of CS (total body - 17.26 %, trunk - 22.73 %, and R1 box - 21.21 %, all p < 0.05). Surgical remission of hypercortisolism is characterized by improvement of body composition, particularly fat reduction, easily detectable with DXA during routine clinical practice. [ABSTRACT FROM AUTHOR]

Objective Cushing's disease ( CD) presents a remarkable preponderance in female gender, with a female-to-male ratio of 3-8:1. The aim of this study was to evaluate gender-related differences in the presentation of CD, as regards: biochemical indices of hypercortisolism; sensitivity of diagnostic tests; clinical features and complications of disease. Methods We retrospectively studied 84 adult patients with CD, 67 women and 17 men, evaluated at diagnosis. We compared the features of the disease between the sexes and analysed the effect of gender on CD complications, adjusted for potential confounders (age, gonadal status, BMI, urinary free cortisol values). Results We observed no differences between males and females as regards age at diagnosis, disease duration and BMI. Men, compared with women, presented higher urinary free cortisol values ( P < 0·001) and ACTH values ( P < 0·05). As regards diagnostic tests, men presented a lower ACTH response to DDAVP stimulation ( P < 0·05). The pituitary tumour itself was less easily visualized by pituitary MRI in males compared with females ( P < 0·05). Furthermore, some complications of disease were more frequent or more severe in men, in particular hypokalaemia ( P < 0·05), hypercoagulable state and osteoporosis at lumbar spine ( P < 0·01), with consequent higher risk of vertebral fractures. Male gender was found to be an independent risk factor for dyslipidaemia, severity of hypertension, lumbar osteoporosis and fractures. Conclusions Although CD is less frequent in male patients, in this gender, it presents with more florid clinical manifestations and may imply more diagnostic difficulties. [ABSTRACT FROM AUTHOR]

Objective Cushing's disease ( CD) has an uncertain prognosis because patients achieving remission after transsphenoidal pituitary neurosurgery ( TSS) may relapse. We aimed to identify factors predicting relapse, focusing on desmopressin ( DDAVP) and corticotropin-releasing hormone ( CRH) tests after surgery. Materials and methods Fifty-seven patients with CD (mean age 36 years) after TSS experienced remission (24 cases), late relapse ( LR) (15 cases), or persistent disease (18 cases). Results The median time to relapse was 40 months. ACTH levels increased after both DDAVP and CRH stimulation, with a significantly higher response in the late recurrence group, showing this to be an indicator of increased risk of relapse. In the logistic regression model, a rise in ACTH >9 pg/ml after DDAVP and >36·7 pg/ml after CRH showed a sensitivity of 93% and 73%, respectively, a specificity of 82% and 76% in LR group. The area under the curve was 0·91 for DDAVP, 0·80 for CRH and 0·95 for DDAVP+ CRH test, i.e. the combined tests performed better than each test alone, but not to a statistically significant degree. A response to both tests resulted in a positive predictive value ( PPV) of 100%, while no response to either test in a negative predictive value ( NPV) of 100%. Conclusions ACTH hyper-responsiveness to DDAVP stimulation proved a valuable indicator of relapsing patients with high sensitivity and specificity; in selected cases when a clear high increment of ACTH level is not evident, the CRH test might be used as additional tool to confirm the risk of future relapses. [ABSTRACT FROM AUTHOR]

Objective: Salivary cortisol has recently been suggested for studies on the hypothalamic-pituitary-adrenal (HPA) axis. The lack of circadian rhythm is a marker of Cushing's syndrome (CS), and some authors have reported that low salivary cortisol levels may be a marker of adrenal insufficiency. The aim of our study was to define the role of salivary cortisol in specific diagnostic settings of HPA axis disease. Subjects and methods: We analyzed morning salivary cortisol (MSC) and late-night salivary cortisol (LNSC) levels in 406 subjects: 52 patients with Cushing's disease (CD), 13 with ectopic CS, 17 with adrenal CS, 27 with CD in remission (a mean follow-up of 66±39 months), 45 with adrenal incidentaloma, 73 assessed as having CS and then ruled out for endogenous hypercortisolism, 75 with adrenal insufficiency, and 104 healthy subjects. Results: A LNSC value above 5.24 ng/ml differentiated CS patients from controls with high sensitivity (96.3%) and specificity (97.1%); we found higher LNSC levels in ectopic CS patients than in CD patients. We found no difference in MSC and LNSC levels between patients with CD in remission and healthy subjects. Both MSC and LNSC levels were higher in patients with adrenal incidentaloma than in healthy controls. A MSC value below 2.65 ng/ml distinguished patients with adrenal insufficiency from controls with high sensitivity (97.1%) and specificity (93.3%). Conclusions: Salivary cortisol is a useful tool to assess endogenous cortisol excess or adrenal insufficiency and to evaluate stable CD in remission. [ABSTRACT FROM AUTHOR]

Cushing's syndrome (CS) is a severe condition that results from chronic exposure to elevated circulating cortisol levels; it is a rare but potentially life-threating condition, especially when not timely diagnosed and treated. Even though the diagnosis can be straightforward in florid cases due to their typical phenotype, milder forms can be missed. Despite the availability of different screening tests, the diagnosis remains challenging as none of the available tools proved to be fully accurate. Due to the ubiquitous effect of cortisol, it is easy understandable that its excess leads to a variety of systemic complications including hypertension, metabolic syndrome, bone damages and neurocognitive impairment. This article discusses clinical presentation of CS with an eye on the most frequent cortisol-related comorbidities and discuss the main pitfalls of first- and second-line tests in endogenous hypercortisolism diagnostic workup. [ABSTRACT FROM AUTHOR]

[Display omitted] Endogenous Cushing's syndrome (CS) is a rare condition due to prolonged exposure to elevated circulating cortisol levels that features its typical phenotype characterised by moon face, proximal myopathy, easy bruising, hirsutism in females and a centripetal distribution of body fat. Given the direct and indirect effects of hypercortisolism, CS is a severe disease burdened by increased cardio-metabolic morbidity and mortality in which visceral adiposity plays a leading role. Although not commonly found in clinical setting, endogenous CS is definitely underestimated leading to delayed diagnosis with consequent increased rate of complications and reduced likelihood of their reversal after disease control. Most of all, CS is a unique model for systemic impairment induced by exogenous glucocorticoid therapy that is commonly prescribed for a number of chronic conditions in a relevant proportion of the worldwide population. In this review we aim to summarise on one side, the mechanisms behind visceral adiposity and lipid metabolism impairment in CS during active disease and after remission and on the other explore the potential role of cortisol in promoting adipose tissue accumulation. [ABSTRACT FROM AUTHOR]

The contribution of functional and/or structural remodeling to reduced coronary flow velocity reserve (CFVR), reflecting impaired coronary microcirculation in Cushing's syndrome (CS), has not been clearly elucidated. We aimed to identify the potential mechanisms of coronary microvascular impairment in CS. We studied 15 CS patients (11 female, age 50 ± 9 years) without clinical evidence of cardiovascular disease. Coronary flow velocity in the left anterior descending coronary artery was measured by transthoracic Doppler echocardiography, at rest, and during adenosine infusion. Average peak flow velocities, CFVR, and microvascular resistance in baseline (BMR) and hyperemic conditions (HMR) were assessed. CFVR ≤2.5 was considered a marker of microvascular disease (CMD). Diastolic function (E/e′), global longitudinal strain (GLS) and fractional pulse pressure (fPP), an index of arterial stiffness, were also assessed. CMD was present in 5 patients (33.3%). CMD was primarily driven by increased baseline peak flow velocity (29 ± 12 versus 19.6 ± 4.2 cm/s, p =.03) in the presence of decreased BMR (3.62 ± 0.6 versus 5.46 ± 1.4 mm Hg·s/cm, p =.03). Moreover, urinary cortisol and E/e′ were higher (p =.001 and p =.001, respectively) and GLS was lower (p =.009) in patients with CMD. fPP was higher in patients with CMD (p =.01). Urinary cortisol correlated to CFVR (p =.008), E/e′ (p <.0001) and GLS (p <.0001). fPP directly correlated to average peak flow velocities at rest (p =.01) and inversely to BMR (p =.03). Functional microvascular regulatory impairment seems to be the potential mechanism of CMD in CS. CMD seems to be related to decreased myocardial contractility and diastolic dysfunction associated with cortisol excess. Unlabelled Image • Mechanisms of coronary microvascular impairment in Cushing's syndrome are unknown. • 15 Cushing's syndrome patients without cardiovascular disease were included. • Coronary microvascular dysfunction was present in 33% of patients. • Disturbed autoregulation may be the mechanism of coronary microvascular impairment. [ABSTRACT FROM AUTHOR]