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Biomedical subjects

K Toutouzas

Publications and source records attributed to K Toutouzas.

At least 19 recordsLinked to original sources
PubMed2006

Increased coronary sinus blood temperature: correlation with systemic inflammation.

BACKGROUND: Recent studies have shown that patients with single vessel coronary artery disease (CAD) suffering from acute coronary syndromes (ACS) have increased coronary sinus (CS) blood temperature compared with the right atrium (RA). The aim of this study was to investigate whether there is a correlation between systemic inflammatory indexes and CS temperature and whether there is a difference in CS temperature between patients with single vs. multivessel disease. MATERIALS AND METHODS We included consecutive patients scheduled for coronary angiography for recent-onset chest pain evaluation. We measured C-reactive protein (CRP) levels in the study population. Coronary sinus and RA blood temperature measurements were performed by a 7F thermography catheter. DeltaTau was calculated by subtracting the RA from the CS blood temperature. RESULTS: The study population comprised 53 patients with ACS, 25 patients with stable angina (SA) and 22 subjects without CAD (control group). DeltaTau was greater in patients with ACS and with SA compared with the control group (0.22 +/- 0.10 degrees C, 0.18 +/- 0.04 degrees C vs. 0.14 +/- 0.07 degrees C, P < 0.01 for both comparisons). The ACS group had greater DeltaTau compared with the SA group, although the difference did not reach statistical significance (P = 0.09). Eighteen (39.1%) out of 46 patients with multivessel disease had three-vessel disease and 28 (60.8%) had two-vessel disease. DeltaTau between patients with multivessel and single vessel disease was similar (0.22 +/- 0.01 degrees C, 0.19 +/- 0.01 degrees C, P = 0.17). The levels of CRP were well correlated with DeltaTau (R = 0.35b, P < 0.01). CONCLUSIONS: Systemic inflammation is well correlated with CS temperature; thus, an inflammatory process could be the underlying mechanism for increased heat production from the myocardium.

Aged↗
PubMed2002

Microalbuminuria is associated with unfavourable cardiac geometric adaptations in essential hypertensive subjects.

We sought in this study to examine the relationship between microalbuminuria and cardiac geometry since a slight increased urinary albumin excretion (UAE) and increased left ventricular (LV) mass have both been identified as predictors of cardiovascular events in hypertensive subjects. For this purpose, microalbuminuria was determined in three non-consecutive 24-h urine samples as UAE of 20-200 mg/24 h in a group of 249 untreated hypertensive subjects. Echocardiographic classification of patients into LV geometric patterns was based on relative wall thickness values and on gender-specific values for LV mass index (LVMI). The group of patients with microalbuminuria (n = 119) was matched for age, sex, body mass index, smoking status and plasma cholesterol level with the group of patients without microalbuminuria (n = 130). Subjects with microalbuminuria had significantly increased LVMI (111 vs 90 g/m(2), P < 0.0001), relative wall thickness (0.46 vs 0.41, P < 0.001) and office systolic and diastolic blood pressure (161 vs 148 and 101 vs 97 mmHg, respectively, P < 0.005). For the pooled population, UAE was positively correlated to LVMI (r = 0.46, P < 0.001) and relative wall thickness (r = 0.47, P < 0.001). In the entire population, normal LV geometry, concentric LV remodelling, eccentric and concentric LV hypertrophy was found in 34%, 33%, 12% and 21%, respectively. The prevalence of normal LV geometry was significantly higher in normoalbuminuric compared with microalbumnuric subjects (55 vs 14%, P < 0.001) while the prevalence of concentric LV hypertrophy was significantly higher in microalbuminuric compared with normoalbuminuric subjects (32 vs 5%, P < 0.0001). Multiple regression analysis revealed that concentric LV hypertrophy was significantly associated with increased values of UAE and mean arterial pressure. In conclusion, the higher prevalence of unfavourable LV geometric patterns in hypertensive subjects with microalbuminuria compared with those without microalbuminura, may account for the worse cardiovascular outcomes associated with the presence of an increased UAE in hypertensive subjects.

Adult↗
PubMed2002

Statin treatment is associated with reduced thermal heterogeneity in human atherosclerotic plaques.

AIMS: Heat released from atherosclerotic plaques as a result of the local inflammatory process, may be measured in vivo by a thermography catheter. Statins seem to have an antiinflammatory effect which results in plaque stabilization. The aim of this study was to investigate the effect of statins on plaque temperature. METHODS AND RESULTS: The study population included 72 patients: 21 with effort angina, 32 with unstable angina and 19 with acute myocardial infarction. In the study group, 37 patients received statins for more than 4 weeks and 35 were not receiving statins. We measured the temperature difference (deltaT) between the atherosclerotic plaque and the proximal vessel wall (background temperature) using a thermography catheter. The statistical analysis showed that the mean value of deltaT was higher in the untreated group compared to the treated-with-statin, group (0.56+/-0.41 vs 0.29+/-0.33 degrees C, P<0.01). Moreover, a progressive increase in deltaT by type of clinical syndrome was observed in both groups (statin group; effort angina: 0.24+/-0.15, unstable angina: 0.26+/-0.26, acute myocardial infarction: 0.40+/-0.28, vs untreated group; effort angina: 0.41+/-0.26, unstable angina: 0.44+/-0.28, acute myocardial infarction: 0.84+/-0.52, P<0.05). Multivariate analysis showed that treatment with statins was an independent factor in temperature variation, after taking into account the effect of the clinical syndrome (P<0.05). CONCLUSIONS: Patients on statin treatment produce less heat from the culprit coronary lesion than those not treated. Thus, statins seem to have a favourable effect on heat release from atherosclerotic plaques, and whether this effect has an impact on plaque stabilization needs to be investigated in future studies.

Arteriosclerosis↗
PubMed2001

Laparoscopic cholecystectomy in adults with sickle cell disease.

BACKGROUND: Chronic hemolysis predisposes adults with sickle cell disease (SCD) to the formation of bilirubinate cholelithiasis. METHODS: To study the impact of laparoscopic cholecystectomy (LC) on this groups, we reviewed our records of all patients with SCD and cholelithiasis treated electively from 1991 to 1999. During that period, 13 consecutive patients with SCD underwent elective LC for symptomatic cholelithiasis. Nine patients (69.2%) were managed with a preoperative transfusion regimen to achieve a hemoglobin value of >/=10 g/dl, independent of hemoglobin S percentage. Five patients who presented with jaundice were referred for preoperative endoscopic retrograde cholangiopancreatography (ERCP), which identified choledocholithiasis in two of them. Three other patients underwent intraoperative cholangiography, which revealed common bile duct stones in one patient. RESULTS: One patient developed pyrexia for 2 days. There were no vaso-occlusive crises or deaths. The mean hospital stay was 3.3 days. CONCLUSIONS: LC has proven to be a safe and efficacious method for the treatment of symptomatic cholelithiasis in this high-risk population. Hematologists are now more willing to refer early, well-prepared patients with SCD and uncomplicated gallbladder disease for elective LC.

Adult↗
PubMed2001

Stent deployment in calcified lesions: can we overcome calcific restraint with high-pressure balloon inflations?

Although significant coronary artery (CA) calcification is believed to affect stent deployment, the exact impact on stent deployment after high-pressure balloon inflations is unknown. Intracoronary intravascular examination (ICUS) was performed in 27 moderate-severe calcified CA lesions before and after stent implantation. In case of unsatisfactory results (in-stent area < 90%, minimal in-stent diameter/maximal in-stent diameter < 0.8), further inflations up to 20 atm guided by ICUS were applied. Initially, stent expansion was adequate in 10 stents (37%) and symmetric in 19 (70%). After inflation at 20 atm, stents with adequate expansion increased to 16 (59%, P = 0.0036), but stents with symmetry decreased to 13 (48%, P = 0.0045). Stent expansion was inversely correlated to the arc of calcium (r = -0.8, P < 0.0001). There were five patients with clinical restenosis at 6 months (18%). Increases in stent lumen area with high-pressure balloon inflations in moderate-severe calcified CA lesions are at the expense of symmetry. This may affect clinical restenosis.

Aged↗
PubMed2001

Thermography of human arterial system by means of new thermography catheters.

In this case report, we present the first clinical application of three thermography catheters for temperature measurements in the coronary arteries, the aorta, and the femoral arteries. The entire procedure was performed successfully without complications. Larger clinical studies are required in order to examine the feasibility for the application of the aortic and the peripheral artery thermography catheters and the clinical significance of temperature measurements in these arteries. Cathet Cardiovasc Intervent 2001;54:51-58.

Aorta↗
PubMed2001

Increased local temperature in human coronary atherosclerotic plaques: an independent predictor of clinical outcome in patients undergoing a percutaneous coronary intervention.

OBJECTIVES: We investigated the midterm clinical significance of human coronary atherosclerotic plaques temperature after a successful percutaneous coronary intervention. BACKGROUND: Previous studies have shown an increased temperature in human atherosclerotic plaques. However, the prognostic significance of atherosclerotic plaque temperature in patients undergoing a successful percutaneous intervention is unknown. METHODS: We prospectively investigated the relation between the temperature difference (deltaT) between the atherosclerotic plaque and the healthy vessel wall and event-free survival among 86 patients undergoing a successful percutaneous intervention. Temperature was measured by a thermography catheter, as previously validated. The study group consisted of patients with effort angina (EA) (34.5%), unstable angina (UA) (34.5%) and acute myocardial infarction (AMI) (30%). RESULTS: The deltaT increased progressively from EA to AMI (0.132 +/- 0.18 degrees C in EA, 0.637 +/- 0.26 degrees C in UA and 0.942 +/- 0.58 degrees C in AMI). The median clinical follow-up period was 17.88 +/- 7.16 months. The deltaT was greater in patients with adverse cardiac events than in patients without events (deltaT: 0.939 +/- 0.49 degrees C vs. 0.428 +/- 0.42 degrees C; p < 0.0001). The deltaT was a strong predictor of adverse cardiac events during the follow-up period (odds ratio 2.14, p = 0.043). The threshold of the deltaT value, above which the risk for an adverse cardiac event was significantly increased, was 0.5 degrees C. The incidence of adverse cardiac events in patients with deltaT > or = 0.5 degrees C was 41%, as compared with 7% in patients with deltaT < 0.5 degrees C (p < 0.001). CONCLUSIONS: Increased local temperature in atherosclerotic plaques is a strong predictor of an unfavorable clinical outcome in patients with coronary artery disease undergoing percutaneous interventions.

Aged↗
PubMed2000

Heat production of atherosclerotic plaques and inflammation assessed by the acute phase proteins in acute coronary syndromes.

Several studies have shown that inflammation plays an important role in the pathogenesis of coronary heart disease (CHD). Serum amyloid A (SAA) and C-reactive protein (CRP) reactants of the acute phase of inflammation, have been shown to be increased in patients with CHD. Recently ex vivo studies demonstrated that some types of atherosclerotic plaques show substantially warmer regions. A catheter-based technique has been developed to measure the temperature of human arteries in vivo. Therefore, the aim of the present study was to measure the luminal surface temperature in patients with CHD and to correlate it with the acute phase proteins in order to discriminate the role of inflammation in heat production in acute coronary syndromes. Sixty patients were studied with CHD (20 with stable angina, 20 with unstable angina and 20 with acute myocardial infarction) and 20 sex- and age-matched controls without coronary artery disease, by measuring plasma levels of SAA, CRP, plasma lipids and intracoronary arterial luminal wall temperature. Intracoronary temperature was measured with a thermography catheter developed in our Institution: a thermistor probe with a temperature accuracy of 0.05 degrees C, was attached at the distal end of a long 3F polyurethane shaft. It was found that the median temperature differences at the site of the lesion from the core temperature was increased in patients with unstable angina (1.025 degrees C) and acute myocardial infarction (2.150 degrees C) compared with stable angina (0.300 degrees C), P<0.001 for each comparison. Furthermore, stable angina has increased temperature differences compared with controls (0.200 degrees C, P<0.001). There were very good correlations between CRP and SAA with the temperature (r=0.796, P=0.01 and r=0.848, P=0.01, respectively). Local heat at the site of lesion is increased in patients with acute coronary syndromes and may arise from an aggressive inflammatory response occurring in these situations. The sensitive measurement of plaque temperature as a prognostic marker may be useful in the management of coronary heart disease.

Angina Pectoris↗
PubMed2000

Aortic pressure-diameter relation in patients with non-insulin dependent diabetes mellitus: new insights.

AIMS/HYPOTHESIS: Type II (non-insulin-dependent) diabetes mellitus is associated with macrovascular disease. Therefore, we investigated the aortic elastic properties by a new method in patients with diabetes and control patients matched with them. METHODS: Patients with Type II diabetes (n = 20) and control patients without diabetes (n = 21) were enrolled in the study. All patients had coronary artery disease. Instantaneous aortic diameter was measured by an intravascular catheter developed in our institution. Instantaneous aortic pressure was measured simultaneously at the same aortic level with a catheter-tip micromanometer. Thus, aortic pressure-diameter loops were obtained and slope and intercept were calculated. Aortic distensibility, stiffness constant and energy loss were also calculated. RESULTS: The mean age and the heart rate were similar in the two groups. The pulsatile changes in aortic diameter were greater in the control group (0.94 +/- 0.4 vs 1.28 +/- 0.4 mm, p < 0.01). The stiffness of the aortic wall was greater in diabetic patients as indicated from the following variables: the distensibility was less in patients with diabetes (1.16 +/- 0.6 vs 1.95 +/- 0.9 cm2 x dyne(-1) x 10(-6), p <0.01); the slope was greater (113.4 +/- 120.1 vs 51.61 +/- 3.3 mmHg/mm, p < 0.01) and the intercept was less in diabetic patients (-2301.9 +/- 2692.9 vs -1114.45 +/- 295.6 mmHg, p < 0.01); the stiffness constant was greater in patients with diabetes (1.66 +/- 1.8 vs 0.77 +/- 0.8 mm(-1), p < 0.03). Aortic energy loss was, however, similar between the groups. CONCLUSION/INTERPRETATION: In patients with non-insulin dependent diabetes aortic elastic properties, evaluated by pressure-diameter relation, are impaired. This could play an important part in the development of vascular complications related to diabetes.

Aorta, Thoracic↗
PubMed2000

Stents covered by autologous venous grafts: feasibility and immediate and long-term results.

BACKGROUND: Previous experimental studies with a new covered stent, the autologous venous graft-covered stent (AVGCS), have shown favorable results. The aim of this study was to evaluate the feasibility and safety of this new technique in human coronary arteries and to compare the long-term outcome with uncovered stents. METHODS AND RESULTS: A venous graft was removed from an upper limb. A conventional stent then was covered by the venous graft. Fifty-eight AVGCS were implanted in 56 patients, including 16 patients with acute coronary syndromes (ACS). Additionally, in 114 patients, 138 uncovered stents were implanted, serving as a control group, including 38 patients with ACS. The procedure was successful in all patients. Stent thrombosis was observed in 3 patients in the control group and in 1 patient with an AVGCS. There was a trend for the minimal luminal diameter to be greater in the AVGCS group at follow-up (P =.07), and statistical significance was observed in patients with ACS (P <.01). The target vessel revascularization and the restenosis rates were similar between the 2 groups. In patients with ACS, the restenosis rate was less (P <.04) and there was a trend for target vessel revascularization to be less in covered stents (P =.09). The event-free survival rate at 4 years was 85% in the AVGCS group versus 81% in the control group (P = not significant); in ACS it was 94% versus 78%, respectively (P = not significant). Stents covered by thicker venous grafts were associated with improved clinical outcome. CONCLUSIONS: Stents covered by autologous venous grafts may be safely prepared without complications. This technique may prove to be a useful means, especially in patients with ACS.

Coronary Angiography↗
PubMed2000

Implantation of stents covered by autologous arterial grafts in human coronary arteries: a new technique.

UNLABELLED: A renewed interest in radial artery conduits for bypass surgery has emerged during the last few years. In order to combine a surgical with a percutaneous technique, stents were covered by radial arterial grafts. The purpose of this study was to evaluate the feasibility of, and the immediate and long-term results after, intracoronary implantation of stents covered by autologous arterial grafts. METHODS: A graft was removed from the radial artery. A conventional stent was then covered by the arterial graft. The autologous arterial graft was stabilized on the stent by sutures. Fifteen covered stents were implanted in 15 patients (56.1 +/- 17.3 years old) in all coronary vessels. RESULTS: The procedure of stent covering was feasible and short in duration. Procedural success was 100% with no in-hospital stent thrombosis, Q-wave myocardial infarction or death. In 14 patients (93.3%), including the patients with clinical restenosis, a repeat angiography was performed (minimum lumen diameter immediately after procedure: 3.01 +/- 0.22 mm, at follow-up: 2.56 +/- 0.90 mm). Target lesion revascularization was required in 2 patients. The event-free survival rate at 2 years was 87%. CONCLUSION: Intracoronary implantation of stents covered by an autologous arterial graft may be performed safely with excellent long-term results. A multicenter study is required to assess the efficacy.

Adult↗
PubMed1999

Thermal heterogeneity within human atherosclerotic coronary arteries detected in vivo: A new method of detection by application of a special thermography catheter.

BACKGROUND: Activated macrophages play an important role in the pathogenesis of acute ischemic syndromes. It has been postulated that detection of heat released by activated inflammatory cells of atherosclerotic plaques may predict plaque rupture and thrombosis. Previous ex vivo studies have shown that there is thermal heterogeneity in human carotid atherosclerotic plaques. METHODS AND RESULTS: To measure the temperature of human arteries in vivo, we developed a catheter-based technique. Ninety patients (45 with normal coronary arteries, 15 with stable angina [SA], 15 with unstable angina [UA], and 15 with acute myocardial infarction [AMI]) were studied. The thermistor of the thermography catheter has a temperature accuracy of 0.05 degrees C, a time constant of 300 ms, and a spatial resolution of 0.5 mm. Temperature was constant within the arteries of the control subjects, whereas most atherosclerotic plaques showed higher temperature compared with healthy vessel wall. Temperature differences between atherosclerotic plaque and healthy vessel wall increased progressively from SA to AMI patients (difference of plaque temperature from background temperature, 0. 106+/-0.110 degrees C in SA, 0.683+/-0.347 degrees C in UA, and 1. 472+/-0.691 degrees C in AMI). Heterogeneity within the plaque was shown in 20%, 40%, and 67% of the patients with SA, UA, and AMI, respectively, whereas no heterogeneity was shown in the control subjects. CONCLUSIONS: Thermal heterogeneity within human atherosclerotic coronary arteries was shown in vivo by use of a special thermography catheter. This heterogeneity is larger in UA and AMI, suggesting that it may be related to the pathogenesis.

Aged↗
PubMed1999

Stents covered by an autologous arterial graft in porcine coronary arteries: feasibility, vascular injury and effect on neointimal hyperplasia.

OBJECTIVE: The use of stents has improved results after balloon coronary angioplasty. Several materials have been proposed for covering the metallic surface of the stent to reduce the rate of subacute thrombosis and restenosis. In our institution, an autologous arterial graft was used for covering the external surface of a conventional stent. The angiographic and histological response in a porcine coronary artery model was investigated. METHODS: An autologous arterial graft was removed from the femoral artery and carefully prepared. Subsequently, a conventional stent was covered externally by the arterial graft. Twenty-two covered stents and 22 uncovered regular stents were implanted alternatively in the coronary arteries of 22 pigs. One animal died immediately after the procedure, due to thrombus formation in the uncovered stent. Six animals were sacrificed at seven days and the remaining animals were sacrificed at two months. Before the sacrifice, coronary angiography was performed in all animals. RESULTS: Thrombosis was detected in two control segments and in one covered stented segment. After seven days, the luminal surface of the covered stents was covered by a new endothelial layer in contrast to partial endothelial cell appearance in the control group. The angiographic parameters were similar between the two groups. Histologically, the covered stents were associated with less vascular injury compared to uncovered stents. In covered stents a trend towards reduction of maximal intimal hyperplasia was detected (covered: 116.6 +/- 47.75 vs uncovered: 150.25 +/- 46.81 microns, p = 0.08); also the thickness of the arterial media was reduced (covered: 21.34 +/- 10.28 vs uncovered: 102.63 +/- 18.71 microns, p = 0.02). The luminal and vessel areas were similar in the two groups. CONCLUSIONS: The preparation and implantation of the autologous arterial graft-covered stent is technically safe and feasible. This type of covered stent results in accelerated endothelialization, less vascular injury, thinning of the arterial media and a trend to reduce the intimal hyperplasia in normal coronary arteries.

Animals↗
PubMed1999

Coronary artery distensibility in diabetic patients with simultaneous measurements of luminal area and intracoronary pressure: evidence of impaired reactivity to nitroglycerin.

OBJECTIVES: This study investigated whether noninsulin dependent diabetes mellitus (NIDDM) adversely affects the elastic properties of the coronary arteries in patients with coronary artery disease (CAD) and NIDDM. BACKGROUND: Attenuated vascular smooth muscle dilation to exogenous donors of nitric oxide, such as nitroglycerin, has been observed with forearm blood flow studies in patients with NIDDM. METHODS: Twenty patients with CAD and NIDDM (diabetics), and 20 patients with only CAD (nondiabetics) were evaluated. Intracoronary ultrasound (ICUS) imaging with simultaneous intracoronary pressure (P2) recordings were performed at the imaging site with 0.014 in fiber-optic high fidelity pressure monitoring wire. The same wire was used as guide wire for the ICUS catheter. Sites with less than 50% luminal stenosis by ICUS were studied. Recordings were done before and after 300 microg of intracoronary nitroglycerin (IC-NTG). Electrocardiographic tracings recorded simultaneously with ICUS images were used for timing. Systolic and diastolic cross-sectional lumen area (CSLA) and coronary artery distensibility (C-DIST) were measured, C-DIST = [(systolic CSLA-diastolic CSLA)/[(intracoronary pulse pressure) x (diastolic CSLA)]] x 1,000. RESULTS: Diabetics had smaller CSLA (diabetics = 8.6 +/- 0.6 mm2, nondiabetics = 11.5 +/- 0.5 mm2, p < 0.01). Although C-DIST was similar before IC-NTG in the two groups, it became significantly lower in diabetics after IC-NTG (diabetics C-DIST = 3.02 +/- 0.14 mm Hg(-1), nondiabetics C-DIST = 4.21 +/- 0.15 mm Hg(-1), p < 0.01). Degrees of circumference involved, total plaque burden and composition were similar in both groups. CONCLUSIONS: Noninsulin dependent diabetes mellitus reduces C-DIST after IC-NTG administration.

Adult↗