Konstantinos Lampropoulos

Biomechanical response of ascending thoracic aortic aneurysms: association with structural remodelling

Ascending thoracic aortic aneurysms (ATAA) were resected from patients during graft replacement and non-aneurysmal vessels during autopsy. Tissues were histomechanically tested according to region and orientation, and the experimental recordings reduced with a Fung-type strain–energy function, affording faithful biomechanical characterisation of the vessel response. The material and rupture properties disclosed that ATAA and non-aneurysmal aorta were stiffer and stronger circumferentially, accounted by preferential collagen reinforcement. The deviation of microstructure in the right lateral region, with a longitudinal extracellular matrix and smooth muscle element sub-intimally, reflects the regional differences in material properties identified. ATAA had no effect on strength, but caused stiffening and extensibility reduction, corroborating our histological observation of deficient elastin but not collagen content. Our findings may serve as input data for the implementation of finite element models, to be used as improved surgical intervention criteria, and may further our understanding of the pathophysiology of ATAA and aortic dissection.

Predictive value of inter-atrial block for new onset or recurrent atrial fibrillation: A systematic review and meta-analysis

BACKGROUND AND OBJECTIVES Inter-atrial block (IAB) is characterized by a delay of inter-atrial conduction and is defined electrocardiographically by a P-wave duration (PWD)>120ms. Several studies have implicated IAB in the development of new onset atrial fibrillation (AF), whereas others have reported no significant associations. Moreover, there has been no systematic evaluation of the predictive value of IAB in AF recurrence. Therefore, we conducted a systematic review and meta-analysis to examine whether IAB predicts new onset AF or AF recurrence. METHODS PubMed and Embase databases were searched through 30th July 2017 for studies investigating the relationship between IAB and AF. RESULTS The initial search identified 260 studies, of which 16 studies met the inclusion criteria. This meta-analysis included 18,204 patients (mean age 56±13, 48% male) with a mean follow-up period of 15.1years. IAB significantly predicted new onset AF (hazard ratio [HR]: 2.42, 95% confidence interval [CI]: 1.44 to 4.07, P=0.001; 84%). For partial IAB, the risk of new onset AF did not reach statistical significance (HR: 1.42, 95% CI: 0.85 to 2.34; P=0.18; I2=13%). Contrastingly, advanced IAB was a significant predictor of new onset AF with a pooled HR of 2.58 (95% CI: 1.35 to 4.96; P<0.01; I2=67%). IAB also predicted AF recurrence after ablation (HR: 2.59, 95% CI: 1.35 to 4.96; P<0.01; I2=67%). CONCLUSIONS IAB is a significant predictor of both new onset AF and AF recurrence.

Prosthetic heart valve obstruction: thrombolysis or surgical treatment?

Prosthetic valve thrombosis is a potentially life-threatening complication associated with high morbidity and mortality. Transthorasic and transoesophageal echocardiography play an important role to the diagnosis and provides incremental information about the optimal treatment strategy, while fluoroscopy and cardiac computed tomography may be of added value. Guidelines differ on whether surgical treatment or fibrinolysis should be the treatment of choice for the management of left-sided prosthetic valve thrombosis and these uncertainties underline the need for further prospective randomized controlled trials. Thrombus size, New York Heart Association functional class of the patient, the possible contraindications, the availability of each therapeutic option and the clinician’s experience are important determinants for the management of prosthetic valve thrombosis.

Adverse Bioeffects of Ultrasound Contrast Agents Used in Echocardiography: True Safety Issue or “Much Ado About Nothing”?

Ultrasound contrast agents, consisting of gas-filled microbubbles, have long been used to enhance ultrasonographic imaging of various organs and in several settings. In echocardiography, after their first use for Doppler signal enhancement, their applications have expanded and several studies, combining a range of stress modalities with myocardial contrast echocardiography have shown the clinical utility of these agents. In experimental isolated heart animal models, the interaction of ultrasound with echo-contrast microbubbles was shown to have significant biologic effects when the acoustic energy of the beam exceeded a threshold, leading them to rupture and causing cavitation phenomena; the observed consequences in the experimental setting included microvascular damage, transient decrease of contractile performance and increased lactate production. From the clinical point of view, the reporting of a number of serious adverse events - whose association with the echo-contrast agents was debated - has led to the addition of warning boxes in the prescribing documentation of these preparations. On the other hand, clinical studies including high numbers of patients have shown good safety and tolerance of contrast use during stress echocardiography, both for left ventricle opacification and myocardial perfusion imaging. The present review aims at presenting a balanced account of the existing data regarding the mechanisms and clinical implications of echo-contrast bioeffects, in order to make an informed assessment of their safety in clinical practice.

Pre-loading therapy with statins in patients with angina and acute coronary syndromes undergoing PCI

Statins constitute the most powerful class of drugs for cardiovascular risk reduction associated to atherosclerosis. Their important pharmacological properties include reduction of serum lipid concentrations and non-lipid related, pleotropic effects such as anti-inflammatory action. Previous largescale randomized studies have demonstrated the beneficial effects of statin loading prior to elective percutaneous coronary intervention (PCI) for the reduction of periprocedural myocardial infarction and prevention of major adverse cardiac events at 30 days. The present review summarizes the data from major randomized trials that evaluated the clinical benefit of statin pretreatment in the setting of PCI resulting in a better understanding of their impact on reduction of interventional complications.

Severe tricuspid regurgitation and isolated right heart failure due to thyrotoxicosis

We describe the case of a patient presented with isolated right heart failure with atrial fibrillation and severe tricuspid regurgitation due to hyperthyroidism. Treatment of the thyroid disease resulted in the disappearance of signs of right heart failure and resolution of the valve incompetence and normalization of the heart rhythm. Although thyrotoxicosis may be associated with congestive heart failure, isolated right heart failure with marked tricuspid regurgitation is rarely seen.

Fibroblast growth factor 21 in cardio-metabolic disorders: a systematic review and meta-analysis

BACKGROUND Fibroblast growth factor 21 is a signalling protein involved in cell differentiation, morphogenesis, proliferation and metabolism. Recent studies have associated increased levels of FGF21 in the development of cardiovascular diseases, whereas others have reported no significant associations. Therefore, this systematic review and meta-analysis evaluated the value in predicting the risk of cardio-metabolic disorders and mortality. METHODS PubMed and EMBASE were searched until 5th September 2017 for studies that evaluated the roles of FGF21 levels in cardio-metabolic disorders. RESULTS A total of 183 and 301 entries were retrieved; 24 studies met the inclusion criteria. Four studies were identified by an additional search. Therefore, 28 studies were included in the final meta-analysis. High FGF21 levels significantly predicted the incidence of coronary artery disease (hazard ratio [HR]: 1.29; 95% confidence interval [CI]: 1.06-1.55; P < 0. 01; I2 = 48%) and the risk of metabolic syndrome (HR: 1.70, 95% CI: 1.35-2.15; P < 0.0001 I2 = 24%). In diabetes mellitus, FGF21 predicted disease incidence or progression (HR: 1.35, 95% CI: 1.06-1.72, P < 0.05, I2 = 69%) and worsening renal failure (HR: 1.06, 95% CI: 1.03-1.09, P < 0.0001, I2 = 47%). FGF21 also predicted all-cause mortality (HR: 3.00, 95% CI: 1.23-7.33; P < 0.05; I2 = 51%), and cardiovascular mortality (HR: 2.33, 95% CI: 1.08-4.99, P < 0.05, I2 = 75%). CONCLUSION FGF21 significantly predicts the incidence of coronary artery disease, the risks of metabolic syndrome, diabetes mellitus and renal progression in diabetes. It also predicted all-cause and cardiovascular mortality.

Cancer antigen-125 and risk of atrial fibrillation: a systematic review and meta-analysis

Background Cancer antigen-125 (Ca-125) is traditionally recognised as a tumour marker and its role in cardiovascular diseases has been studied only in recent years. Whether Ca-125 is elevated in patients with atrial fibrillation (AF) and its levels predict the risk of AF remains controversial. Therefore, we conducted a systematic review and meta-analysis of the association between Ca-125 levels and AF. Methods PubMed and EMBASE databases were searched until 1 June 2017 for studies that evaluated the association between Ca-125 and AF. Inclusion criteria included studies that compare Ca-125 in patients with and without AF, or those reporting HRs/ORs for risk of AF stratified by Ca-125 levels. Results A total of 39 entries were retrieved from the databases, of which 10 studies were included in the final meta-analysis. Ca-125 was significantly higher in patients with AF compared with those in sinus rhythm (mean difference=16 U/mL, 95% CI 2 to 30 U/mL, P<0.05; I2: 98%). Ca-125 significantly increased the risk of AF (HR: 1.39, 95% CI 1.06 to 1.82, P<0.05; I2: 84%). Conclusion Ca-125 was significantly higher in patients with AF than in those in sinus rhythm, and high Ca-125 is predictive of AF occurrence. However, the high heterogeneity observed means there is an uncertainty in the relationship between Ca-125 and AF, which needs to be confirmed by larger prospective studies.

Large artery biomechanical, geometrical, and structural remodeling elicited by long-term propranolol administration in an animal model

BACKGROUND Limited attention has been paid to the role of beta-adrenergic blocking agents on large artery function/structure, despite being clinically useful for treating many forms of cardiovascular disease. OBJECTIVE To assess long-term consequences of beta-blocker administration on the biomechanical properties, geometry, and histological structure of two major elastic arteries. METHODS Healthy male rats received water with their food, while beta-blockade was produced in rats by adding propranolol in their drinking water. The thoracic aorta and carotid artery were resected after three months for biomechanical (failure and inflation-extension) testing along with geometrical and histological evaluation. RESULTS The thoracic aorta presented increased strength longitudinally in propranolol-treated than untreated rats, resulting from increased adventitial collagen content. The distensibility of carotid artery increased in propranolol-treated rats at low-to-physiologic pressures, resulting from decreased medial collagen content. Structural remodeling was characterized by reduced lumen diameter, wall mass, and thickness-to-radius ratio. The latter, together with the greater resorption of the media than adventitia, related with the measured opening angle decrease in propranolol-treated rats. CONCLUSIONS The geometrical/biomechanical remodeling was mediated by the hemodynamic effects of propranolol treatment, namely the reduced blood flow, and served to normalize in vivo hoop stresses as well as vessel compliance.

Treatment of mobile right heart thrombi with low-molecular-weight heparin

Treatment of choice in patients with mobile thrombi in the right heart chambers is still controversial owing to the increased risk of recurrent pulmonary embolism (PE). Thrombolysis and surgical or catheter embolectomy are the preferred options. We present a case of an elderly patient with PE and free-floating atrial thrombi who was treated successfully with low-molecular-weight heparin (LMWH).