G. Louridas

Home care delivery through the mobile telecommunications platform: The Citizen Health System (CHS) perspective

Health delivery practices are shifting towards home care. The reasons are the better possibilities for managing chronic care, controlling health delivery costs, increasing quality of life and quality of health services and the distinct possibility of predicting and thus avoiding serious complications. For the above goals to become routine, new telemedicine and information technology (IT) solutions need to be implemented and integrated in the health delivery scene, and these solutions need to be assessed through evidence-based medicine in order to provide solid proof for their usefulness. Thus, the concept of contact or call centers has emerged as a new and viable reality in the field of IT for health and telemedicine. In this paper we describe a generic contact center that was designed in the context of an EU funded IST for health project with acronym Citizen Health System (CHS). Since the generic contact center is composed by a number of modules, we shall concentrate in the modules dealing with the communication between the patient and the contact center using mobile telecommunications solutions, which can act as link between the internet and the classical computer telephony communication means. We further elaborate on the development tools of such solutions, the interface problems we face, and on the means to convey information from and to the patient in an efficient and medically acceptable way. This application proves the usefulness of wireless technology in providing health care services all around the clock and everywhere the citizen is located, it proves the necessity for restructuring the medical knowledge for education delivery to the patient, and it shows the virtue of interactivity by means of using the limited, yet useful browsing capabilities of the wireless application protocol (WAP) technology.

Haemodynamic factors and the important role of local low static pressure in coronary wall thickening

UNLABELLED BACKGROUND/STUDY OBJECTIVES: The purpose of our study was to investigate the possible correlation between blood flow physical parameters and the wall thickening in typical human coronary arteries. METHODS Digitized images of seven transparent arterial segments prepared post-mortem were adopted from a previous study in order to extract the geometry for numerical analysis. Using the exterior outline, reconstructed forms of the vessel geometries were used for subsequent computational fluid dynamic analysis. Data was input to a pre-processing code for unstructured mesh generation. The flow was assumed to be two-dimensional, steady, laminar with parabolic inlet velocity profile. The vessel walls were assumed to be smooth, inelastic and impermeable. Non-Newtonian power law was applied to model blood rheology. The arterial wall thickening was measured and correlated to the wall shear stress, static pressure, molecular viscosity, and near wall blood flow velocity. RESULTS Wall shear stress, static pressure and near wall velocity magnitude exhibit negative correlation to wall thickening, while molecular viscosity exhibits positive correlation to wall thickening. CONCLUSION There is a strong correlation between the development of vessel wall thickening and the blood flow physical parameters. Amongst these parameters the role of local low wall static pressure is predominant.

The citizen health system (CHS): a Modular medical contact center providing quality telemedicine services

In the context of the Citizen Health System (CHS) project, a modular Medical Contact Center (MCC) was developed, which can be used in the monitoring, treatment, and management of chronically ill patients at home, such as diabetic or congestive heart failure patients. The virtue of the CHS contact center is that, using any type of communication and telematics technology, it is able to provide timely and preventive prompting to the patients, thus, achieving better disease management. In this paper, we present the structure of the CHS system, describing the modules that enable its flexible and extensible architecture. It is shown, through specific examples, how quality of healthcare delivery can be increased by using such a system.

Predicting the Risk of Rupture of Abdominal Aortic Aneurysms by Utilizing Various Geometrical Parameters: Revisiting the Diameter Criterion

The authors estimated noninvasively the wall stress distribution for actual abdominal aortic aneurysms (AAAs) in vivo on a patient-to-patient basis and correlated the peak wall stress (PWS) with various geometrical parameters. They studied 39 patients (37 men, mean age 73.7 ± 8.2 years) with an intact AAA (mean diameter 6.3 ± 1.7 cm) undergoing preoperative evaluation with spiral computed tomography (CT). Real 3-dimensional AAA geometry was obtained from image processing. Wall stress was determined by using a finite-element analysis. The aorta was considered isotropic with linear material properties and was loaded with a static pressure of 120.0 mm Hg. Various geometrical parameters were used to characterize the AAAs. PWS and each of the geometrical characteristics were correlated by use of Pearsons rank correlation coefficients. PWS varied from 10.2 to 65.8 N/cm2 (mean value 37.1 ± 9.9 N/cm2). Among the geometrical parameters, the PWS was well correlated with the mean centerline curvature, the maximum centerline curvature, and the maximum centerline torsion of the AAAs. The correlation of PWS with maximum diameter was nonsignificant. Multiple regression analysis revealed that the mean centerline curvature of the AAA was the only significant predictor of PWS and subsequent rupture risk. This noninvasive computational approach showed that geometrical parameters other than the maximum diameter are better indicators of AAA rupture.

In-Hospital and Long-Term Prognostic Value of Fibrinogen, CRP, and IL-6 Levels in Patients with Acute Myocardial Infarction Treated with Thrombolysis

Plasma fibrinogen, C-reactive protein (CRP), and interleukin-6 (IL-6) levels in patients with acute myocardial infarction (AMI) receiving thrombolysis have been related to prognosis. The aim of this study was to investigate the time course of plasma fibrinogen, CRP, and IL-6 levels during the in-hospital phase in patients with AMI receiving thrombolysis, and their relationship to in-hospital and prognosis after 12-months follow-up. In 40 patients presenting with AMI within 6 hours of symptom onset and treated with thrombolysis, plasma fibrinogen, CRP, and IL-6 levels were measured on admission and after 6, 12, 24, 48, and 72 hours; 7 days; and 6 months. Patients with other diseases that can alter fibrinogen, CRP, or IL-6 levels were excluded. Patients had a clinical follow-up at 6 and 12 months, and the following cardiac events were recorded: cardiac death, recurrent angina, recurrent AMI, and heart failure. Plasma fibrinogen concentrations decreased significantly (p<0.01 vs admission levels) at 12 hours (425 ±94 vs 322 ±132 mg/dL), started to increase at 24 hours, reached peak value at 72 hours (602 ±209 mg/dL), remained elevated at 7 days, and were back to admission levels at 6 months (375 ±79 mg/dL). CRP levels increased significantly at 12 hours (0.73 ±0.43 vs 0.23 ±0.11 mg/dL, p<0.01), reached peak value at 72 hours (7.66 ±3.28 mg/dL), decreased significantly on day 7 (2.32 ±1.17 mg/dL), and at 6 months were within normal limits (0.49 ±0.29 mg/dL). IL-6 levels increased significantly at 6 hours (14.03 ±8.13 vs 6.37 ±3.88 pg/mL, p<0.05), reached peak value at 24 hours (59.49 ±23.57 pg/mL), started to decrease at 48 hours, and at 6 months were within normal limits (2.25 ±1.24 pg/mL). During the in-hospital phase 33 patients had an uneventful course and 7 patients had complications (3 post-AMI angina; 4 heart failure). During the 12-month follow-up period 28 patients had an uneventful course, and 12 patients had complications (1 cardiac death, 5 recurrent angina, 2 recurrent AMI, and 4 heart failure). Regarding the in-hospital prognosis, fibrinogen, CRP, and IL-6 levels were significantly higher (p<0.05) in patients with complications from 48 to 72 hours, from 12 hours until day 7, and from 6 hours until day 7, respectively. During the 12-month follow-up period fibrinogen, CRP, and IL-6 levels were significantly higher in patients with complications (at 48, 24, and 24 hours, respectively) only in the subgroup of patients who had complications within the first 6 months following AMI. Multivariate analysis showed that CRP at 48 hours was the most important factor related to in-hospital prognosis (p=0.02), and ejection fraction followed by CRP at 24 hours (p=0.02) to 6-month prognosis (p=0.018). Fibrinogen, CRP, and IL-6 levels alter in patients with AMI receiving thrombolysis, and are related both to in-hospital and to 6-month follow-up prognosis.

Evidence of Left Ventricular Dysfunction in Asymptomatic Elderly Patients with Non-insulin-dependent Diabetes Mellitus

Diabetic cardiomyopathy is a distinct entity in diabetic patients with congestive heart failure, who have no angiographic evidence of significant coronary artery stenosis. The aim of this study was to evaluate left ventricular (LV) function in 24 elderly patients (mean age 67 ±2 years) with type 2 diabetes, who were asymptomatic and had no history of hypertension, or coronary or valvular heart disease. LV systolic indices (ejection fraction [EF] and fractional shortening [FS]), diastolic indices (E wave, A wave, E/A ratio, isovolumic relaxation time [IVRT] and deceleration time [DT]) and the myocardial performance index (MPI) were evaluated with echocardiography. Compared to controls (24 age- and gender-matched normal subjects), the E wave was reduced (0.60 ±0.10 m/sec vs 0.72 ±0.08 m/sec, p<0.05), the A wave was increased (0.77 ±0.07 m/sec vs 0.68 ±0.06 m/sec, p<0.05), the E/A ratio was decreased (0.78 ±0.20 vs 1.06 ±0.18, p<0.001) and both IVRT and DT were prolonged (0.115 ±0.01 sec vs 0.09 ±0.01 sec, p<0.001 and 0.240 ±0.04 sec vs 0.180 ±0.03 sec, p<0.001, respectively). The MPI was significantly increased (0.640 ±0.170 vs 0.368 ±0.098, p<0.001). LV diastolic function and the MPI are markedly impaired in asymptomatic elderly patients with type 2 diabetes.

Usefulness of colour tissue Doppler imaging in assessing aortic elastic properties in Type 1 diabetic patients

Aims  Diabetes mellitus (DM) is associated with macrovascular disease and impaired aortic function. We hypothesized that the change in aortic elastic properties could be investigated with colour tissue Doppler imaging (CTDI) in Type 1 diabetic patients and that these findings could be related to the aortic stiffness index.

Evidence of ischemic preconditioning in patients experiencing first non-ST-segment elevation myocardial infarction (NSTEMI)

BACKGROUND Several studies have demonstrated the protective effects of preinfarction angina in Q wave myocardial infarction, implicating the role of ischemic preconditioning but this role remains uncertain in patients with a NSTEMI. Subendocardial viability in NSTEMI patients, is thought to be less dependent on collateral circulation and thus more likely to be protected by other mechanisms such as preconditioning. METHODS We have studied prospectively 40 patients with first NSTEMI and with angiographically proven poor or no collateral development and compared two groups; those with versus those without preinfarction angina. All in-hospital events, such as recurrent angina, congestive heart failure, arrhythmias and reinfarction were recorded. Serum markers of myocardial necrosis (CPK, CPK-MB, AST) and discharge QTc values were estimated. RESULTS Preconditioned patients suffered less recurrent angina (18 vs. 55% P=0.014), congestive heart failure (0 vs. 22%, P=0.02), arrhythmic events (0 vs. 27%, P=0.008) and had significant smaller values of mean peak CPK (381 +/- 152 vs. 859 +/- 496 I.U./l, P=0.0008), mean peak CPK-MB (45.5 +/- 24.6 vs. 105.2 +/- 87 I.U./l, P=0.01), mean peak AST (59.8 +/- 23.1 vs. 112.4 +/- 64.3 I.U./l, P=0.003) and QTc value at discharge (0.42 +/- 0.03 vs. 0.46 +/- 0.05 s, P=0.005) than patients without preconditioning. Multiple logistic regression analysis confirmed that the absence of preinfarction angina (relative risk 9.10, 95% CI 2.08-40.00, P=0.003) was a significant predictor of in-hospital complications. CONCLUSIONS Preinfarction angina constitutes a strong clinical correlate to ischemic preconditioning in patients with first NSTEMI, offering serious protection, by improving in-hospital outcome and reducing infarct size.

Non-diabetic hyperglycaemia correlates with angiographic coronary artery disease prevalence and severity.

AIM The role of glycaemia as a coronary artery disease (CAD) risk factor is controversial, and the optimal glucose level is still a matter of debate. For this reason, we assessed the prevalence and severity of angiographic CAD across hyperglycaemia categories and in relation to haemoglobin A(1c) (HbA(1c)) levels. METHODS We studied 273 consecutive patients without prior revascularization undergoing coronary angiography for suspected ischaemic pain. CAD severity was assessed using three angiographic scores: the Gensinis score; extent score; and arbitrary index. Patients were grouped, according to 2003 American Diabetes Association criteria, into those with normal fasting glucose (NFG), impaired fasting glucose (IFG) and diabetes mellitus (DM). RESULTS CAD prevalence was 2.5-fold higher in both the IFG and DM groups compared with the NFG group. Deterioration of glycaemic profile was a multivariate predictor of angiographic CAD severity (extent score: P=0.027; arbitrary index: P=0.007). HbA(1c) levels were significantly higher among CAD patients (P=0.016) and in those with two or more diseased vessels (P=0.023) compared with the non-CAD group. HbA(1c) levels remained predictive of CAD prevalence even after adjusting for conventional risk factors, including DM (adjusted OR: 1.853; 95% CI: 1.269-2.704). CONCLUSION Non-diabetic hyperglycaemia, assessed either categorically by fasting glucose categories or continuously by HbA(1c) levels, correlates with the poorest angiographic outcomes.

Coronary arterial tree extraction based on artery tracking and mathematical morphology

An algorithm for the unsupervised extraction of the coronary arterial tree in single-view angiograms is proposed. Its output is a structural description of the coronary arterial tree (skeleton and borders) along with accurate information for the coronary artery dimensions. The method consists of two stages. (i) Arterial tree detection, where the approximate centerline and borders of the coronary arterial tree are extracted through a recursive artery tracking method based on circular template analysis for the local artery border detection. (ii) Artery skeleton and border estimation, where the accurate skeleton and borders of each artery segment of the arterial tree are computed based on the morphological tools of homotopy modification and watershed transform. Specifically, the approximate centerline and borders of each artery segment computed at the first stage are used for constructing its enclosing area where the defined skeleton and border curves are considered as markers. Experimental results using digitized coronary angiograms are presented.