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Biomedical subjects

Konstantinos Toutouzas

Publications and source records attributed to Konstantinos Toutouzas.

At least 19 recordsLinked to original sources
PubMed2006

Alterations of pressure waveforms along the coronary arteries and the effect of microcirculatory vasodilation.

OBJECTIVES: We sought to investigate the differences of pressure waveforms at a distal point of an epicardial coronary artery comparatively to the ostium and to assess the effect of microcirculatory vasodilation on them. BACKGROUND: Pressure waveforms in the systematic circulation and their alterations along the aorta due to wave reflections from the periphery have been extensively studied. However, similar data regarding intracoronary pressure waveforms and the effects of coronary microcirculation on them are limited. METHODS: In 18 patients who underwent diagnostic coronary angiogram or percutaneous coronary intervention in the left circumflex or the right coronary artery, we studied pressure waveforms recorded by a high-fidelity pressure wire, which was advanced to the ostium and to a distal site of the free of significant lesions left anterior descending coronary artery. Pressure recording was performed both at rest and at hyperemia induced by intravenous infusion of adenosine. Analysis of pressure waveforms at the frequency domain was performed with Fast Fourier Transform. RESULTS: At baseline conditions, distal pressure waveforms were characterized by higher pulsatility, higher presystolic wave and higher amplitude of the 11th to the 15th harmonics. Hyperemia increased the pulsatility, compressed the notch and decreased the amplitude of higher than the 10th harmonics of distal waveforms. CONCLUSIONS: This study identifies differences of pressure waveforms between proximal and distal sites of free of significant lesions coronary arteries, which are affected by the status of coronary microcirculation and may therefore facilitate assessment of microvascular disease.

Adenosine↗
PubMed2006

Primary gastric melanoma: a case report.

Melanoma accounts for 1-3 per cent of all malignant tumors. Except cutaneous, other less common melanomas include, among others, those in the GI tract. However, their primary or secondary nature is often difficult to establish. Referring to the stomach, scattered cases of primary melanomas have been reported in the literature. We report a case of a man with an ulcerated sub-mucosal mass at the antrum of the stomach, manifested with dull upper abdominal pain, nausea, vomiting, fatigue and anemia. This lesion was histologically proved to be melanoma. A detailed clinical and laboratory investigation revealed no primary site elsewhere. To our knowledge, very few cases of primary gastric melanoma have been reported. Our case is the fourth ever published and the first located at the antrum of the stomach. The debate upon the primitive nature of such lesions still persists. Thus, specific diagnostic criteria have been proposed.

Abdominal Pain↗
PubMed2006

Relation between local temperature and C-reactive protein levels in patients with coronary artery disease: effects of atorvastatin treatment.

Although previous studies have shown systemic inflammatory activation the relation with the local plaque inflammatory activation has not been extensively studied. The present study investigated the relation between local and systemic inflammatory activation in patients with coronary artery disease and the impact of atorvastatin treatment. We included 215 patients undergoing percutaneous coronary intervention; of them 140 were treated with atorvastatin. Patients with stable angina (SA) and acute coronary syndromes (ACS) were included. Systemic inflammation was assessed by serum C-reactive protein (CRP), soluble adhesion molecules levels and local plaque inflammatory activation by coronary thermography. Temperature difference (DeltaT) was assigned as the difference between the proximal vessel wall temperature from the maximal temperature at the culprit plaque. Patients with ACS (n=78) had increased DeltaT compared to patients with SA (n=137) (0.16+/-0.10 degrees C versus 0.08+/-0.07 degrees C, P<0.001). Patients treated with atorvastatin had lower DeltaT compared to untreated patients (0.10+/-0.07 degrees C versus 0.15+/-0.10 degrees C, P<0.01). DeltaT was less in the treated group compared to the untreated group in patients with SA and ACS (ACS: 0.13+/-0.08 degrees C versus 0.20+/-0.11 degrees C, P<0.01, SA: 0.08+/-0.06 degrees C versus 0.13+/-0.08 degrees C, P=0.03). Although a correlation was found between CRP levels and DeltaT (R=0.29, P<0.01), in certain groups a discrepancy between CRP levels and DeltaT was observed. In 25% of patients with low DeltaT CRP levels were >1mg/dl and in 35.5% of patients with high DeltaT CRP was <2mg/dl. The correlation between soluble adhesion molecules and DeltaT did not reach statistical significance. Although there is a correlation between widespread and local inflammatory activation in patients with coronary artery disease, a discrepancy between culprit plaque and systemic inflammatory activation is observed. Atorvastatin has a parallel effect on systemic and local inflammatory process in patients with coronary artery disease.

Aged↗
PubMed2006

Coronary sinus thermography in idiopathic dilated cardiomyopathy: correlation with systemic inflammation and left ventricular contractility.

BACKGROUND: Previous studies have demonstrated that patients with heart failure have increased myocardial heat production. Coronary sinus (CS) thermography is a new method for the evaluation of left ventricular heat production. AIMS: We investigated whether the CS blood temperature is increased in patients with idiopathic dilated cardiomyopathy (DCM) compared to a control group and whether the CS blood temperature correlates with ejection fraction and systemic inflammatory activation. METHODS AND RESULTS: We included 25 patients with DCM and 22 healthy subjects. Temperature measurements were performed using a new thermography catheter. Temperature difference (DeltaT) was defined as the difference between the CS and RA blood temperature. The CRP levels were also measured. DeltaT was significantly greater in patients with DCM compared to the controls (0.25+/-0.09 vs 0.14+/-0.07 degrees C, p<0.01). DeltaT and EF were inversely correlated in patients with DCM (R=0.43). We categorized patients with DCM into two groups using a CRP cut-off value of < or =1 mg/dL. DeltaT in patients with high CRP was less (0.21+/-0.06 degrees C) compared to patients with low CRP (0.30+/-0.08 degrees C, p=0.01). CONCLUSIONS: In patients with DCM increased heat production from the myocardium, as estimated from the coronary sinus blood temperature, was demonstrated, interestingly there was no correlation with systemic inflammatory activation.

Body Temperature↗
PubMed2006

Elevated plaque temperature in non-culprit de novo atheromatous lesions of patients with acute coronary syndromes.

OBJECTIVES: We investigated whether there is increased temperature in non-culprit lesions, and the correlation of clinical syndrome with heat production of non-culprit lesions. BACKGROUND: There is a controversy regarding whether there is widespread inflammation involving non-culprit lesions, or whether inflammatory involvement is limited to the culprit lesion. Coronary thermography assesses the local inflammatory involvement in atherosclerotic lesions. METHODS: We included patients suffering from stable angina (SA) or acute coronary syndrome (ACS). All patients had two or more angiographically detectable lesions at different arteries. Culprit lesions should be identified in all patients. Patients with chronic total occlusions and multiple significant lesions at the culprit vessel were excluded. We measured at each non-culprit lesion the temperature difference (DeltaT) between the atherosclerotic plaque and the proximal vessel wall temperature. RESULTS: The study population included 42 patients: 23 with SA, 19 with ACS. The DeltaT in non-culprit lesions was 0.08 +/- 0.07 degrees C. Patients with ACS had a higher temperature difference in non-culprit lesions compared with patients with SA (ACS 0.11 +/- 0.08 degrees C vs. SA 0.05 +/- 0.06 degrees C; p < 0.01). The mean value of DeltaT in non-culprit lesions was higher in the untreated group compared with the treated group with statins (0.11 +/- 0.10 degrees C vs. 0.06 +/- 0.05 degrees C; p = 0.05). CONCLUSIONS: The results of this study show that heat is generated in non-culprit lesions. Moreover, in patients with ACS, temperature difference is increased compared with patients with stable angina.

Aged↗
PubMed2006

Right ventricular infarction mimicking anterior infarction.

It is rare to observe ST elevation in anterior derivations caused by right ventricular branch occlusion. We described the case of a patient with unstable angina who developed acute right ventricular myocardial infarction with ST-segment elevation in anterior precordial leads (V(1)-V(4)) shortly after coronary angiography. Coronary angiogram revealed total occlusion of the right coronary artery (RCA) proximally to the right ventricular branch. This reminds us that the presence of diffuse ST-segment elevation in the precordial leads could be due to acute RCA occlusion. The differentiation of these two entities is important, as their therapies are quite different.

Angina, Unstable↗
PubMed2005

Eight-year clinical and angiographic follow-up after implantation of autologous arterial graft covered stent in a de novo thrombus-containing lesion.

In this case report, we present the clinical and angiographic follow-up 8 years after implantation of autologous arterial graft covered stent in a thrombus-containing lesion in the proximal segment of left anterior descending artery. The patient was asymptomatic after the implantation of the covered stent until 2 months prior to the coronary angiography. In the repeat angiography, the left anterior descending artery was patent at the site of the covered stent implantation. At the proximal and distal sites of the covered stent, there was no restenosis. In this case report, there were no long-term technique-related complications after the successful autologous arterial covered stent deployment.

Blood Vessel Prosthesis Implantation↗
PubMed2005

Intracoronary thermography: does it help us in clinical decision making?

The concept of the "vulnerable" plaque has recently emerged to explain how quiescent atherosclerotic lesions evolve to cause clinical events. The morphologic and immunologic determinants specific for the vulnerable plaque have been reported: a large lipid core (>or=40% plaque volume) composed of free cholesterol crystals, cholesterol esters, and oxidized lipids impregnated with tissue factor; a thin fibrous cap depleted of smooth muscle cells and collagen; an outward (positive) remodeling; inflammatory cell infiltration of fibrous cap and adventitia (mostly monocyte-macrophages, some activated T cells, and mast cells); and increased neovascularity. Despite the large amount of information regarding the morphological characteristics of remote lesions, we lack studies with functional assessment of non-culprit lesions. Coronary thermography is a technique for functional assessment of coronary atherosclerotic plaques. Several catheter designs have been proposed. There are catheters with thermistor(s) and wires with thermal sensors at the distal tip. All designs have several advantages and disadvantages. Despite the current limitations of coronary thermography, we gained important pathophysiological and clinical information regarding the vulnerability of atheromatic plaques. It has been documented both experimentally and clinically that increased heat generation is associated with increased macrophage concentration within the plaque. The correlation between local inflammatory involvement and local heat generation has also been observed with the peripheral inflammatory markers such as C-reactive protein. Whether systemic treatment, with agents such as statins or interventional techniques, such as drug-eluting stents, will have an impact on stabilizing vulnerable plaques need to be determined in future studies. In conclusion, although there are several techniques for evaluating morphologically atheromatic plaques, thermography is a promising method for the functional assessment of vulnerable plaque and has been introduced into clinical practice, with a good predictive value for clinical events in patients with increased temperature in the atherosclerotic plaque.

Coronary Artery Disease↗
PubMed2005

Increased heat generation from atherosclerotic plaques in patients with type 2 diabetes: an increased local inflammatory activation.

OBJECTIVE: Patients with coronary artery disease (CAD) and diabetes show increased inflammatory activation. Thermography detects local inflammatory involvement as heat generation. The aim of this study was to investigate whether patients with CAD and diabetes have increased local heat generation compared with nondiabetic patients. RESEARCH DESIGN AND METHODS: We enrolled patients undergoing percutaneous coronary interventions: 45 diabetic patients and 63 nondiabetic patients, serving as the control group, matched for age, type of clinical syndrome, statin and aspirin intake, and angiographic stenosis (%). Coronary thermography was performed, and temperature difference (DeltaT) between the atherosclerotic plaque and the proximal vessel wall was measured. RESULTS: Patients with diabetes had increased temperature difference compared with nondiabetic patients (DeltaT: 0.17 +/- 0.18 degrees C vs. 0.09 +/- 0.02 degrees C, P = 0.01). Twenty-one diabetic and 22 nondiabetic patients suffered from acute coronary syndromes (ACSs) (P = 0.22). Patients with diabetes and ACSs had increased temperature difference compared with nondiabetic patients with ACSs (DeltaT: 0.29 +/- 0.31 degrees C vs. 0.15 +/- 0.21 degrees C, P = 0.02), which is the same as patients with diabetes and chronic stable angina (DeltaT: 0.09 +/- 0.08 degrees C vs. 0.05 +/- 0.04 degrees C, P = 0.006). Twenty-three diabetic and 30 nondiabetic patients were under therapy with statins (P = 0.72). Patients with diabetes under statins had lower temperature difference compared with untreated patients (DeltaT: 0.11 +/- 0.12 degrees C vs. 0.22 +/- 0.21 degrees C, P = 0.02), which is the same as nondiabetic patients under statins (DeltaT: 0.05 +/- 0.04 degrees C vs. 0.13 +/- 0.18 degrees C, P = 0.01). CONCLUSIONS: Patients with diabetes have increased temperature difference compared with nondiabetic patients. Patients with diabetes under statins showed decreased temperature difference compared with untreated patients, suggesting that statins have a favorable effect in patients with diabetes and CAD.

Angioplasty, Balloon, Coronary↗
PubMed2004

Temperature of blood in the coronary sinus and right atrium in patients with and without coronary artery disease.

We measured the blood temperature of the coronary sinus and the right atrium in control subjects and patients with significant stenoses in the right or left coronary arteries. Coronary sinus temperature was increased in patients with coronary artery disease compared with the control group and was found to be a prognostic factor for mid-term clinical outcome.

Body Temperature↗
PubMed2004

Detection of increased temperature of the culprit lesion after recent myocardial infarction: the favorable effect of statins.

BACKGROUND: Increased thermal heterogeneity has been demonstrated in atherosclerotic plaques, with the higher temperature recorded in acute myocardial infarction (MI). Dietary or treatment interventions reduce heat production. The purpose of the present study was to investigate whether increased plaque temperature is maintained for a prolonged period after MI and the role of statin administration. METHODS: We enrolled 55 patients, 29 with recent MI and 26 with chronic stable angina (CSA). Total cholesterol, C-reactive protein (CRP), interleukin-6 (IL-6) and soluble adhesion molecules were measured in the study population. All patients underwent coronary plaque temperature measurements. Temperature difference (DeltaT) was designated as the temperature of the culprit atherosclerotic plaque minus the temperature of the proximal healthy vessel wall. RESULTS: Under treatment with statins were 19 patients with recent MI and 14 with CSA. In patients with recent MI DeltaT was 0.19 +/- 0.18 degrees C, while in patients with CSA was 0.10 +/- 0.08 degrees C (P = .03). Patients treated with statins had lower DeltaT compared to untreated patients (0.10 +/- 0.11 versus 0.20 +/- 0.18 degrees C, P = .01). Treated patients with recent MI had similar DeltaT compared to CSA patients treated with statins (0.13 +/- 0.13 versus 0.07 +/- .06 degrees C, P = .14), while untreated patients with recent MI had substantially increased DeltaT compared to untreated patients with CSA (0.28 +/- 0.22 versus 0.14 +/- 0.10 degrees C, P = .04). DeltaT was positively correlated with CRP (R = 0.50, P < .01), IL-6 (R = 0.58, P < .01), and intercellular adhesion molecule-1 (R = 0.40, P = .03) levels. CONCLUSION: Increased plaque temperature is observed for an extended period after myocardial infarction, indicating that the inflammatory process is sustained after plaque rupture. Statins have a beneficial effect after MI on plaque temperature.

Aged↗
PubMed2004

Inflammation and restenosis after percutaneous coronary interventions.

The role of inflammation in the development of restenosis after percutaneous coronary interventions has been investigated in several studies. There is an interaction of inflammatory activation and vascular wall response to injury leading to intimal hyperplasia. Percutaneous interventions trigger inflammatory reactions leading to the development of intimal hyperplasia. This reaction is even more prominent in atheromatic plaques in which inflammatory cells have already been activated. In the clinical setting there are several methods for the recognition of the inflammatory activation. In this article we review the data for the role of inflammatory process in restenosis and the significance of identifying the inflamed lesions prior to the intervention. Moreover, the therapeutic implications for the inhibition of inflammatory activation are mentioned.

Angioplasty, Balloon, Coronary↗
PubMed2004

Lack of increased left main coronary artery dimensions in hypertensive patients with left ventricular hypertrophy and coronary artery disease. An intracoronary ultrasound study.

OBJECTIVES: Left main coronary artery dimensions were evaluated in patients with and without arterial hypertension, in the presence of coronary artery disease, and correlated to left ventricular mass. METHODS AND RESULTS: Intracoronary ultrasound was performed in 25 patients (pts) with coronary artery disease and hypertension (+HTN) and in 25 pts with coronary artery disease only (-HTN). Maximal left main dimensions and left ventricular mass index (LVMI) were measured. +HTN pts had greater LVMI compared to -HTN, (+HTN = 183 +/- 17 g/m2 vs. -HTN = 82 +/- 22 g/m2, p < 0.0001), while maximal left main vessel area was similar (25.99 +/- 5.01 mm2 vs. 25.62 +/- 3.3 mm2, p = 0.8). No correlation was found between LVMI and left main vessel area in + HTN. CONCLUSIONS: Pts with +HTN despite the increased LVMI do not manifest increased LM dimensions. This may affect mid-term clinical outcome.

Adrenergic beta-Antagonists↗
PubMed2004

The cooling effect of coronary blood flow on heart: a new approach.

We tested the hypothesis that blood flow through the coronary arteries may have a cooling effect on heart. The difference (?T) of blood temperature between coronary sinus and right atrium was calculated, during and after acute complete occlusion of blood flow in left coronary artery by balloon dilatation and confirmed by a Doppler guidewire. Coronary sinus blood temperature increased during interruption of coronary blood flow with balloon dilatation.

Blood Flow Velocity↗
PubMed2003

Thermal heterogeneity in stable human coronary atherosclerotic plaques is underestimated in vivo: the "cooling effect" of blood flow.

OBJECTIVES: This study investigated whether temperature measurements are influenced by blood flow. BACKGROUND: Previous ex vivo studies showed marked thermal heterogeneity in atheromatic plaques. In stable lesions, however, trivial in vivo temperature variations are recorded, perhaps due to the "cooling effect" of blood flow. METHODS: Eighteen patients with effort angina were studied. Coronary flow velocity was continuously recorded; over another guidewire, temperature measurements were performed at the proximal vessel wall and at the lesion before, during, and after complete interruption of blood flow by inflation of a balloon. The DeltaTp was assigned as the difference between the proximal vessel wall temperature and the maximal temperature during and after balloon inflation. The DeltaTl was assigned as the difference between the atherosclerotic plaque and the proximal vessel wall. RESULTS: The procedure was not complicated. During and after complete interruption of flow, DeltaTp was 0.012 +/- 0.01 degrees C and -0.006 +/- -0.01 degrees C (p < 0.001), respectively. The DeltaTl was 0.08 +/- 0.04 degrees C at baseline and went to 0.18 +/- 0.05 degrees C (60.5 +/- 14.1% increase) during and 0.08 +/- 0.04 degrees C after flow interruption (p < 0.001). The DeltaTl was greater than DeltaTp during and after impairment of flow (p < 0.001). A correlation between the baseline average peak velocity and DeltaTl during flow interruption was found (R = 0.57, p = 0.01). In seven patients thermal heterogeneity was not detected at baseline, and during balloon inflation DeltaTl increased by 76.0 +/- 8.4%. CONCLUSIONS: Thermal heterogeneity is underestimated in atherosclerotic plaques in patients with effort angina. Potential in vivo underestimation of heat production locally in human atherosclerotic is due to the "cooling effect" of coronary blood flow.

Aged↗
PubMed2003

High success with nonoperative management of blunt hepatic trauma: the liver is a sturdy organ.

HYPOTHESIS: Nonoperative management of liver injuries (NOMLI) is highly successful and rarely leads to adverse events. DESIGN: Prospective observational study. SETTING: High-volume academic level I trauma center. PATIENTS: For 26 months, 78 consecutive unselected patients with liver injuries were followed up prospectively. In the absence of hemodynamic instability or signs of hollow visceral trauma, NOMLI was offered irrespective of the magnitude of the liver injury. Main Outcome Measure Failure of NOMLI, defined as a laparotomy after an initial decision to treat the patient nonoperatively. RESULTS: Of the 78 patients, 23 (29%) were operated on immediately, but only 12 (15%) for bleeding from the liver. All 12 patients required packing in addition to other maneuvers (hepatorrhaphy [n = 8], resection [n = 4], and liver isolation [n = 1]). Of the remaining 55 patients selected for NOMLI, the method failed in 8 for reasons unrelated to the liver injury: 2 underwent a splenectomy, 1 underwent a nephrectomy, 1 had a small-bowel repair, 1 underwent abdominal decompression for abdominal compartment syndrome, and 3 underwent a nontherapeutic laparotomy. The success rate of NOMLI was 85% (47 of 55 patients), but the liver-specific success rate was 100%. Compared with those in whom NOMLI was successful, patients in whom it failed had a higher Injury Severity Score and underwent more blood transfusions, but they had similar liver injury grades. In total, 66 (85%) of liver injuries did not bleed significantly. No adverse events were attributed to NOMLI. CONCLUSIONS: Nonoperative management of liver injuries is safe and effective regardless of the grade of liver injury. Failure of NOMLI is caused by associated abdominal injuries and not the liver. Fluid and blood requirements, the degree of injury severity, and the presence of other abdominal organ injuries may help predict failure.

Abdominal Injuries↗
PubMed2003

A new dedicated stent and delivery system for the treatment of bifurcation lesions: preliminary experience.

We report the first clinical experience in eight patients with a new stent and delivery system specifically designed for the treatment of bifurcational lesions. The device (AST SLK-View system) consists of a premounted stent and a delivery system. The stent has a side aperture, which orients toward the ostium of the side branch. The system allows deployment of the stent while the access to both main and side branches is maintained by two wires. We evaluated this system in nine bifurcations. The location of bifurcations was left descending artery/diagonal branch in four lesions, left circumflex/obtuse marginal branch in three lesions, and postero-lateral branch/posterior descending artery in two lesions. Predilation was performed in six lesions of the main branches and in five lesions of the side branches. The stent was effectively delivered to all bifurcations except for one, in which the target lesion was located at a distal segment and the device could not be delivered. Following stent implantation in the main branch, two lesions at the side branches were treated by stent, while the other lesions were treated by balloon angioplasty without difficulty. Final kissing balloon was performed in four bifurcation lesions. No adverse event was observed during 1 month of clinical follow-up. Treatment of bifurcation lesions with this new dedicated device appears to be feasible. This new device may introduce a new approach for the treatment of coronary bifurcation lesions.

Aged↗