Papers by Michael Demosthenous
Current Cardiology Reviews
: Aortic valve insufficiency (AI) describes the pathology of blood leaking through the aortic val... more : Aortic valve insufficiency (AI) describes the pathology of blood leaking through the aortic valve to the left ventricle during diastole and is classified as mild, moderate or severe according to the volume of regurgitating blood. Intervention is required in severe AI when the patient is symptomatic or when the left ventricular function is impaired. Aortic valve replacement has been considered the gold standard for decades for these patients, but several repair techniques have recently emerged that offer exceptional stability and long-term outcomes. The appropriate method of repair is selected based on the mechanism of AI and each patient’s anatomic variations. This review aims to describe different pathologies of AI based on its anatomy, along with the different surgical techniques of aortic repair and their reported results.
Background: Changes in the myocardial redox state may be a key feature in myocardial pathophysiol... more Background: Changes in the myocardial redox state may be a key feature in myocardial pathophysiology, but their exact role in the development of post-operative complications after coronary bypass grafting (CABG) is unclear. We examined the role of systemic and local myocardial redox state, in the development of post-operative atrial fibrillation (AF) after CABG surgery. We further explored the impact of monocyte chemoattractant protein 1 (MCP-1) as well as IL-6 and CRP on the development of post-operative AF in these patients.Methods: Samples of right atrium appendage as well as blood samples were obtained from 303 patients undergoing elective CABG. Blood samples were obtained in the morning of the surgery. Patients were followed up prospectively for development of postoperative AF until their discharge from the hospital. Myocardial superoxide (O2-.) was determined by lucigenin- enhanced chemiluminescence and peroxynitrite (ONOO-) by urate-inhibitable luminol chemiluminescence. NADP...
Hellenic Journal of Cardiology
Journal of Cardiac Surgery, 2020
Objective: To analyze predictors that influence the learning curve of minimally invasive mitral v... more Objective: To analyze predictors that influence the learning curve of minimally invasive mitral valve surgery (MIMVS). Methods: Patients who underwent MIMVS between March 2010 to March 2015 were retrospectively analyzed. Predictive factors that influence the learning curve were analyzed. Results: One hundred and five patients were included in the analysis. Cardiopulmonary bypass (CPB) time in minutes was 158.72 ± 40.98 and the aortic crossclamp (ACC) time in minutes was 114.48 ± 27.29. There were three operative mortalities, one stroke and five >2+ mitral regurgitation. ACC time in minutes was higher in the low logistic Euroscore II (LES) group (LES < 5% = 118.42 ± 27.94) versus (LES ≥ 5 = 88.66 ± 22.26), P < .05 while creatinine clearance in μmol/L was higher in the LES < 5% group (LES < 5% = 84.32 ± 33.7) versus (LES ≥ 5% = 41.66 ± 17.14), (P < .05). One patient from each group required chest tube insertion for pleural effusion P < .05. The cumulative sum analysis (CUSUM) for the first 25 patients had CPB and ACC times that reached the upper limits. Between 25 to 64 patients the curve remained stable while with the introduction of reoperations and complex surgical procedures the CUSUM reached the upper limits. Conclusions: The learning curve is affected by many factors but this should not desist surgeons from approaching this technique. The introduction of high-risk patients in clinical practice should be carefully measured based on surgeon experience.
Circulation, Nov 3, 2009
Background: Adiponectin is downregulated in obesity, but the existing data regarding its role at ... more Background: Adiponectin is downregulated in obesity, but the existing data regarding its role at different stages of ischaemic heart disease have been conflicting. We evaluated the impact of obesit...
Journal of the American College of Cardiology, 2013
International Journal of Cardiology, 2013
Background: Adiponectin is an adipokine with an important role in cardiovascular system conferrin... more Background: Adiponectin is an adipokine with an important role in cardiovascular system conferring anti-inflammatory and anti-atherogenic effects. Two common single nucleotide polymorphisms (SNP) on adiponectin gene, rs2241766 and rs1501299, have been associated with insulin resistance and diabetes mellitus risk however their effects on cardiovascular risk remain unclear. We examined the impact of rs2241766 and rs1501299 on circulating adiponectin levels, endothelial function and cardiovascular disease risk. Methods: We recruited in total 594 subjects; 462 patients with angiographically confirmed coronary artery disease (CAD) and 132 controls matched for age and gender. rs2241766 and rs1501299 were genotyped by polymerase chain reaction and restriction endonuclease digestion. Serum adiponectin levels were determined by enzyme-linked immunosorbent assay. Endothelial function was assessed by the flow mediated dilatation (FMD) of the brachial artery. Results: rs2241766 had no effects on circulating adiponectin levels or FMD. In subjects without CAD, carriers of the T/T alleles at rs1501299 had lower adiponectin levels (p=0.001) and impaired endothelial function (pb 0.05). After multivariate adjustment none of the SNPs had any effect on CAD risk. However, carriers of the T allele at rs1501299 were at increased myocardial infarction (MI) risk, independently of classic risk factors (OR =2.558 [95%CI =1.587-4.123], p =0.0001). The number of T alleles in both SNPs was strongly associated with MI history (p=0.0001). Conclusions: rs1501299 polymorphism of adiponectin gene affects circulating adiponectin levels and endothelial function in subjects without CAD. Presence of the T variant at rs1501299 on adiponectin gene is independently associated with increased myocardial infarction risk.
Journal of Cardiothoracic and Vascular Anesthesia, 2020
This is a PDF file of an article that has undergone enhancements after acceptance, such as the ad... more This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
Background: Adiponectin (Adpn) is an anti-inflammatory adipokine. In cell culture studies, pro-in... more Background: Adiponectin (Adpn) is an anti-inflammatory adipokine. In cell culture studies, pro-inflammatory cytokines suppress adiponectin’s biosynthesis, however in clinical studies adiponectin le...
Circulation, 2011
Background: Statins improve survival of patients with atherosclerosis, but their direct effects o... more Background: Statins improve survival of patients with atherosclerosis, but their direct effects on human arterial wall are unclear. We examined the effect of atorvastatin on the mechanisms regulati...
European Heart Journal, 2010
International Journal of Surgery and Research, 2015
Background: Intestinal obstruction due to gallstones is a rare condition accounting for 1-4% of c... more Background: Intestinal obstruction due to gallstones is a rare condition accounting for 1-4% of cases of a mechanical small bowel obstruction. Gallstone coleus (gallstone obstruction of the large bowel) is an even more uncommon cause of a mechanical bowel obstruction. Methods: We performed a search of the PubMed database in December 2014. To the best of our knowledge all available case reports and case series were included. Reference sections were searched manually for additional potential cases. Search terms for gallstone coleus were used in all possible combinations. Our exclusion criteria embraced reports of gallstone obstruction of the small bowel, and duplicate cases. We found 57 publications that together produced a total of 63 case reports of gallstone coleus. Conclusion: Gallstone coleus is a rare entity that carries a high mortality. It usually occurs in the elderly, who frequently suffer a wide variety of comorbidities. To lower mortality, it is advocated that in the elderly co-morbid patient, non-invasive options of stone extraction should be trialled as the treatment option of first choice.
European Heart Journal, 2013
netic terms, HNF4A CC genotype (OR=1.50; p=0.006) and PCSK9 GG variant (OR=1.30; p=0.047) showed ... more netic terms, HNF4A CC genotype (OR=1.50; p=0.006) and PCSK9 GG variant (OR=1.30; p=0.047) showed significant increased risk for onset of complication. After logistic regression the two genetic variants remained in the equation: HNF4A CC (OR=3.90; p=0.031) and PCSK9 GG (OR=1.95; p=0.017) with sedentary life (OR=1.71; p<0.0001). Conclusion: According to these results, there are risk factors such as sedentary life and some genetic variants (HNF4A and PCSK9) that are significantly and independently associated with MACE occurrence and allow us to predict vascular complications after CAD diagnosis. If patients have one or more of these conditions, a particularly careful secondary prevention should be ensured.
Clinics in surgery, Sep 23, 2019
Journal of Hypertension, 2018
Objective: PCOS and vitamin D defi ciency are both frequent multifactorial endocrine disorders, l... more Objective: PCOS and vitamin D defi ciency are both frequent multifactorial endocrine disorders, lead to metabolic and early cardiovascular complications. According to actual data, there are an estimated 10.5 million fertile women suffering from PCOS only in the US. With this study we would like to describe the biomechanical changes of small coronary arterioles leading to a higher risk of cardial and cerebral insult.
Journal of Cardiothoracic Surgery, 2018
Introduction: No uniform consensus in the UK or Europe exists, for glycaemic management of patien... more Introduction: No uniform consensus in the UK or Europe exists, for glycaemic management of patients with Diabetes or pre-diabetes undergoing cardiac surgery. Objective: [i] Determine the relationship between glycaemic control and cardiac surgical outcomes; [ii] Compare current vs gold standard management of patients with Diabetes or pre-diabetes undergoing cardiac surgery. Methods: Searches of MEDLINE, NHS Evidence and Web of Science databases were completed. Articles were limited to those in English, German and French. No date limit was enforced.13,232 articles were identified on initial literature review, and 50 relevant papers included in this review. Results: No national standards for glycaemic control prior to cardiac surgery were identified. Upto 30% of cardiac surgical patients have undiagnosed Diabetes. Cardiac surgical patients without Diabetes with pre-operative hyperglycaemia have a 1 year mortality double that of patients with normoglyacemia, and equivalent to patients already diagnosed with Diabetes. Pre-and peri-operative hyperglycaemia is associated with worse outcomes. Evidence regarding tight glycaemic control vs moderate glycaemic control is conflicting. Tight control may be more effective in patients without Diabetes with pre−/peri-operative hyperglycaemia, and moderate control appears more effective in patients with pre-existing Diabetes. Patients with well controlled Diabetes may achieve comparable outcomes to patients without Diabetes with similar glycaemic control. Conclusions: Pre / peri-operative hyperglycaemia is associated with worse outcomes in both patients with, and without Diabetes undergoing CABG. This review supports the pre-operative screening, and optimisation of glycaemic control in patients undergoing cardiac surgery. Optimal glycaemic management remains unclear and clear guidelines are needed.
Takotsubo cardiomyopathy, also known as broken heart syndrome or stress cardiomyopathy, is a form... more Takotsubo cardiomyopathy, also known as broken heart syndrome or stress cardiomyopathy, is a form of transient left ventricular dysfunction. Severe apical and mid left ventricular hypokinesis with hypercontractility of the basal segments is observed. Numerous underlying causes and pathophysiological mechanisms have been proposed including sudden sympathetic activation and increase in the circulating levels of catecholamines resulting in multivessel coronary spasm. Another possible mechanism related to catecholamine-mediated myocardial stunning is direct myocyte injury. Increasing data show that endothelial dysfunction and depleted nitric oxide bioavailability are common in patients with Takotsubo cardiomyopathy. In this chapter we examine in depth the relation between endothelial dysfunction and Takotsubo syndrome.
Journal of Hypertension, 2019
Objective: Sleep Disordered Breathing (SDB) is frequent in stage 5 CKD and in dialysis patients. ... more Objective: Sleep Disordered Breathing (SDB) is frequent in stage 5 CKD and in dialysis patients. Small studies in dialysis patients show that SDB ameliorates in the early months after renal transplantation (Blood Purif 2008) but the long term longitudinal evolution of SDB in renal transplant patients has not been studied. Design and method: We investigated the long term evolution of polysomnographic recordings in 221 renal transplant patients (age: 46.9 ± 11 years). Overall, 404 polysomnographic recordings over a follow up extended up to 110 months (median:52.1) were performed. Longitudinal data analysis was performed by Generalized Estimating Equations (GEE). Results: At baseline, the median value of the apnoea-hypopnea index (AHI) was 1.8 episodes/h [interquartile range (IQR): 0.6-5.0]. One-hundred and sixty-six patients (75%) had a normal AHI (<5). Thirty-seven patients (17%) had mild to moderate SDB (AHI 5 to 14.9) and the remaining 18 (8%) had a severe SDB (AHI>15). AHI was directly related with age (rho = 0.24,P < 0.001), BMI (rho = 0.27,P < 0.001), fi brinogen (rho = 0.16, P = 0.027) and glucose (rho = 0.14,P = 0.035). Episodes of central apnea (n = 173 patients, median: 0.70 episodes/h, IQR: 0.30-1.70) were more frequent than episodes of airways obstruction (n = 79 patients, median:0.40, IQR: 0.20-2.10). The median values of minimum (MinSaO2) and the average nocturnal O2 saturation were 89% and 95.6%. On longitudinal observation, the median AHI rose from 1.8 at baseline to 2.9 and to 3.6 at the second and the third longitudinal visit, respectively (P = 0.009). MinSaO2 significantly worsened over time (1st visit, 87.7 ± 6.7%; 2nd visit, 87.2 ± 7.5%; 3rd visit, 84.8 ± 10.8%, P = 0.048). Central apnoea episodes tended to worsen over time (P = 0.057). In multiple GEE models, BMI (P < 0.001) and C-reactive protein (P = 0.001) emerged as the sole independent longitudinal correlates of AHI and MinSaO2 respectively while male gender associated with MinSaO2 (P = 0.03) but not with the AHI. Conclusions: SDB in renal transplanted patients shows a gradual, linear worsening over a longitudinal observation extended up to 110 months. The BMI rise, a potentially modifi able risk factor, is an important factor underlying the risk for SDB worsening in transplant patients. Infl ammation, an established consequence of overweight/obesity, goes along with SDB worsening in renal transplant patients.
Background: The exact mechanisms by which statins affect endothelial nitric oxide synthase (eNOS)... more Background: The exact mechanisms by which statins affect endothelial nitric oxide synthase (eNOS) biology in human atherosclerosis are unclear. We hypothesized that statin treatment improves nitric...
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Papers by Michael Demosthenous