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Biomedical subjects

P Toutouzas

Publications and source records attributed to P Toutouzas.

At least 19 recordsLinked to original sources
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↗
PubMed2001

Genotype-phenotype assessment in autosomal recessive arrhythmogenic right ventricular cardiomyopathy (Naxos disease) caused by a deletion in plakoglobin.

OBJECTIVES: The purpose of this study was to examine the genotype-phenotype relation with respect to penetrance, age and severity of expression, disease progression and prognosis in a recessively inherited arrhythmogenic right ventricular cardiomyopathy (ARVC). BACKGROUND: Naxos disease is a recessively inherited ARVC caused by a mutation in the gene encoding plakoglobin (cell adhesion protein) in which the cardiac phenotype is associated with palmoplantar keratoderma and woolly hair. METHODS: Twelve families with Naxos disease underwent cardiac and molecular genetic investigation. Serial cardiac assessment with annual resting 12-lead and 24-h ambulatory electrocardiogram (ECG) and two-dimensional echocardiography was performed during 1 to 16 years, median 7 +/- 6 years in all 78 surviving members. RESULTS: Twenty-eight surviving members were homozygous and 40 were heterozygous for the mutation. All adults who were homozygous (n = 26) fulfilled the diagnostic criteria for ARVC, the youngest by the age of 13 years. In eight who were heterozygous, minor ECG or echocardiographic abnormalities were observed. Of the 26 subjects who were affected homozygotes, 92% showed ECG abnormalities, 92% ventricular arrhythmias, 100% right ventricular structural alterations and 27% left ventricular involvement. During follow-up (10 +/- 6 years), 16 (62%) developed structural progression, 12 (46%) arrhythmic events and 7 (27%) heart failure. The annual disease-related and sudden death mortality was 3% and 2.3%, respectively. CONCLUSIONS: Autosomal recessive ARVC caused by a mutation in plakoglobin was 100% penetrant by adolescence. Affected subjects who were homozygous experienced progressive disease with adverse prognosis. A minority of subjects who were heterozygous showed minor ECG/echocardiographic changes, but clinically significant disease did not develop.

Abnormalities, Multiple↗
PubMed2001

Biochemical changes involved in the mechanism of vasovagal syncope.

Vasovagal syncope elicits one of the most powerful transient vasodilatory responses in humans. Many studies have shown an altered neurohumoral response to tilting in patients with vasovagal syncope. Vasopressin (VP) has been of particular interest, but its exact role remains unclarified, whereas the possible role of the potent vasoactive end products of arachidonic acid metabolism has not yet been addressed. We determined the changes in plasma levels of VP, thromboxane (TXA2), and prostacyclin (PGI2) in 34 syncopal patients undergoing a standardized head-up tilt-table testing protocol and compared these changes between patients with positive and negative test results. Blood samples were collected at baseline, 15 minutes in the head-up position, and at the termination of the tilt test (the induction of syncope or the completion of a negative test). Sixteen patients had a positive test result, whereas 18 completed the test without developing any syncopal symptoms. In the tilt-positive group, VP levels presented a 20-fold increase at the time of syncope when compared with baseline levels (p = 0.0000), without any increase at earlier stages. No change was detected at any stage in the tilt-negative patients. We did not find any difference in the levels of PGI2 at any stage in any group of patients or between the 2 groups. TXA2 levels increased significantly at 15 minutes in the upright position in both tilt-positive and tilt-negative patients. No further increase was noticed at the time of syncope in the tilt-positive group, whereas in patients with a negative test result, there was a tendency to decline at the time of the test's completion. It is concluded that although VP is markedly increased during tilt-induced vasovagal syncope, vasoactive amines such as TXA2 and PGI2 play a minor role in the vasodilatory component of the response.

Adolescent↗
PubMed2001

Therapeutic modification of the L-arginine-eNOS pathway in cardiovascular diseases.

L-Arginine is the substrate for nitric oxide production. Endothelium dysfunction could be attributed to L-arginine deficiency or the presence of L-arginine endogenous inhibitors. This hypothesis leads to the assumption that provision of L-arginine could be the key for endothelial function improvement. Many studies have proven that L-arginine has a beneficial effect on endothelium dependent vasoreactivity, as well as on the interaction between vascular wall, platelets and leucocytes. Therefore, individuals with risk factors for atherosclerosis and patients with coronary artery disease or heart failure, could benefit from therapy with L-arginine.

Animals↗
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

Identification of patients with coronary artery disease by assessing diastolic abnormalities during isometric exercise.

BACKGROUND: Previous clinical studies using invasive and noninvasive methods have shown handgrip-induced diastolic abnormalities in patients with coronary artery disease (CAD). HYPOTHESIS: The study was undertaken to determine the utility of Doppler echo- and pressocardiography during hand-grip in discriminating patients with coronary artery disease (CAD) and in those with normal coronary arteries. METHODS: Both methods were obtained in 96 patients with suspected CAD within 24 h before coronary angiography. An abnormal handgrip-Doppler was defined by an early (E) to late (A) transmitral flow velocities ratio (E/A) < 1 during handgrip and a positive handgrip pressocardiographic test (HAT) by an abnormal increase in the A wave/total excursion or prolongation of the absolute or relative (heart-rate corrected) total relaxation time during isometric exercise. RESULTS: Of the 96 patients studied, 23 had normal coronary arteries and 73 showed CAD. In patients with normal coronary arteries, handgrip-Doppler showed an abnormal average E/A at rest and during handgrip, whereas all variables of HAT were within normal limits. In patients with CAD, handgrip-Doppler showed only a moderate handgrip-induced increase in average A (+ 19%, p < 0.001), whereas HAT showed a significant (p < 0.001) increase in mean A wave/total excursion (+ 60%) and decrease in the relative total relaxation time (- 17%). Furthermore, handgrip-Doppler and HAT were abnormal in 15 of 23 (65%, specificity 35%) and the HAT in 5 of 23 (22%, specificity 78%) patients with normal coronary arteries, as well as in 57 of 73 (sensitivity 78%) and 69 of 73 (95%) patients with CAD. CONCLUSIONS: Our study demonstrates that these noninvasive stress tests can become a useful new diagnostic modality for detecting patients with unknown or suspected CAD.

Adult↗
PubMed2001

Chemokines in patients with ischaemic heart disease and the effect of coronary angioplasty.

Percutaneous coronary transluminal angioplasty (PTCA) may release inflammatory mediators such as chemokines. Monocyte chemoattractant protein-1 (MCP-1) and eotaxin (EOX) are monocyte- and eosinophil-specific chemokines involved in the inflammation and pathogenesis of coronary atherosclerosis. A total of 28 patients undergoing elective PTCA, 20 coronary artery disease (CAD) patients undergoing coronary angiography and 28 healthy controls were studied. In PTCA patients before the procedure, MCP-1 plasma levels (441+/-64 pg/ml) were similar to those of CAD patients (430+/-24 pg/ml), and significantly higher compared with controls (145+/-17 pg/ml, P<0.01). MCP-1 rose significantly after 3 and 6 months following PTCA (696+/-89 and 876+/-86 pg/ml, respectively, P<0.01 vs. before PTCA). EOX plasma levels (155+/-14 pg/ml) were similar to those of CAD patients (157+/-14 pg/ml), but significantly higher compared with controls (83.2+/-10 pg/ml, P<0.05). EOX rose significantly 24 h (273+/-41 pg/ml, P<0.05) but not 3 months after PTCA (160+/-20 and 158+/-19 pg/ml, respectively). These findings indicate that chemokine-induced monocyte- and eosinophil-specific chemoattraction is stimulated in patients with coronary artery disease. MCP-1 levels remain significantly elevated for at least 6 months following elective PTCA, suggesting an inflammatory stimulation.

Angioplasty, Balloon, Coronary↗
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↗
PubMed2001

Radiofrequency catheter ablation of posteroseptal accessory pathways--results of a step-by-step ablation approach.

INTRODUCTION: Transcatheter radiofrequency ablation of posteroseptal accessory pathways (AP) is challenging. A number of different interventional approaches have been suggested by different groups. The selection of the initial approach is crucial in order to reduce radiation exposure and the number of unsuccessful lesions applied. We present our ablation technique as guided by a simplified electrocardiographic analysis of the delta wave polarity and the electrophysiologic mapping results. METHODS AND RESULTS: Out of 35 manifest APs encountered in the right (n=17) or the left posteroseptum (n=18) in 35 patients, 34 were successfully ablated. Despite their left sided location, 7 of the 18 "left" sided APs were ablated after switching from an initial arterial to a venous approach looking for an appropriate target site in the right posteroseptal space or within the coronary sinus network. The other 11 left sided APs were ablated in the mitral ring, on 2 occasions, on their atrial aspect through a retrograde transmitral approach. On the contrary, 16 of the 17 "right" sided APs were successfully ablated exclusively through a venous approach. Fourteen of these were ablated in the right posteroseptum, in 2 cases, only after reaching their ventricular aspect. Two right sided APs were interrupted in the coronary sinus os and the middle cardiac vein respectively. CONCLUSION: It appears that even though the electrocardiographic and electrophysiologic location of the AP in the posteroseptal space helps select the appropriate initial approach, it does not always guarantee a successful ablation procedure in the expected site of the corresponding atrioventricular ring. Not uncommonly, it will be necessary to look after intermediate target sites within the coronary sinus to improve the overall ablation success rate.

Adolescent↗
PubMed2001

Acute effect of clonidine on left ventricular pressure-volume relation in hypertensive patients with diastolic heart dysfunction.

We sought to assess the haemodynamic effects of clonidine on left ventricular (LV) pressure-volume relation in patients with diastolic heart dysfunction due to essential hypertension. Towards this end, simultaneous recordings of LV volume (acoustic quantification) and LV pressure (micromanometer) were obtained in 10 such patients before and after drug administration and compared to baseline findings on 10 matched normal controls. The following measurements and calculations were obtained: maximal positive and negative first derivative of LV pressure (peak +dP/dt and peak -dP/dt, respectively), LV minimal and end-diastolic pressure, peak systolic blood pressure, time constant of relaxation (TAU), LV stroke work and LV stiffness constant. The two invasive indexes, LV stiffness constant and TAU classified 10/10 patients as having abnormal LV diastolic function compared with 7/10 patients so classified by Doppler studies. Central sympathetic suppression by a single oral dose of clonidine 0.125 mg in these patients resulted within 60 min in a decrease of heart rate and mean arterial pressure as well as a significant improvement of LV diastolic function indexes. Specifically, the LV stiffness constant (ml(-1)), in normal subjects was 0.0028 vs 0.0152 (P < 0.001) in hypertensive subjects at baseline, vs 0.0053 in hypertensive after clonidine (P < 0.001 vs baseline). Likewise, the E/A ratio, was 1.08 in normal subjects vs 0.88 (P < 0.0001) in hypertensives at baseline, vs 1.28 in hypertensives after clonidine (P < 0.0001 vs baseline). With clonidine the diastolic portion of the pressure-volume curve was displaced downward. In conclusion, clonidine can improve diastolic dysfunction without depressing systolic LV performance. The improvement may be attributable in part to withdrawal of direct sympathetic influence on the myocardium and in part to the indirect effect of systemic, pulmonary and coronary artery relaxation.

Aged↗
PubMed2001

Increased plasma adhesion molecule levels in patients with heart failure who have ischemic heart disease and dilated cardiomyopathy.

BACKGROUND: Inflammatory mechanisms, including leukocyte activation, appear to play a pathogenetic role in the development of heart failure. Vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) are important mediators of leukocyte adhesion to vascular endothelium. The plasma levels of the soluble form of these molecules may be elevated in chronic inflammation. METHODS AND RESULTS: We measured plasma VCAM-1 and ICAM-1 levels (in nanograms per milliliter) with the commercially available enzyme-linked immunosorbent assay method in 12 patients (9 male, 3 female, aged 64 +/- 8 years) with dilated cardiomyopathy and heart failure, in 23 patients (23 male, aged 65 +/- 9 years) with ischemic cardiomyopathy and heart failure, and in 11 healthy control subjects (8 male, 3 female, aged 49 +/- 14 years). Plasma ICAM-1 levels were higher both in patients with dilated cardiomyopathy (363 +/- 77 ng/mL, P <.05) (mean +/- SEM) and in those with ischemic heart disease (320 +/- 32 ng/mL, P <.05) than in control subjects (225 +/- 29 ng/mL). VCAM-1 levels were also higher in both groups with heart failure (664 +/- 73 ng/mL) than in control subjects (551 +/- 60 ng/mL). VCAM-1 levels were higher in patients with class IV compared with those with class II and III heart failure. CONCLUSIONS: Plasma adhesion molecule levels are increased in patients with heart failure and are unrelated to the presence or absence of angiographically demonstrable atherosclerotic coronary artery disease. The plasma level of VCAM-1 correlates with the severity of heart failure.

Aged↗
PubMed2001

Echocardiographic and signal averaged ECG indices associated with non-sustained ventricular tachycardia after repair of tetralogy of fallot.

OBJECTIVE: To identify any possible association between different readily available non-invasive indices and potential malignant ventricular arrhythmias in patients with repaired tetralogy of Fallot. DESIGN: 27 consecutive patients, mean (SD) age 27.3 (11.7) years, were studied 15.7 (6.7) years after corrective surgery for tetralogy of Fallot, using 12 lead ECG, 24 hour Holter recordings, signal averaged ECG, and echocardiography. The following variables were measured: standard QRS duration, filtered QRS duration (fltQRS), low amplitude signal duration, and root mean square voltage of the last 40 ms of the fltQRS (RMS-40), as well as right ventricular systolic pressure, right ventricular ejection fraction, and the ratio of the maximum short axis diameters of the right and left ventricles (RD:LD). RESULTS: All patients had right bundle branch block, with a mean QRS duration of 137.1 (14.9) ms. There were no patients with sustained arrhythmia. Five patients had runs of non-sustained ventricular tachycardia (group A) and the other 22 patients did not (group B). Univariate analysis showed that fltQRS and RD:LD ratio were significantly associated with non-sustained ventricular tachycardia. In addition, a fltQRS >/= 148 ms, low amplitude signal >/= 32.5 ms, RMS-40 </= 23 microV, and RD:LD ratio >/= 1.05 were cut off points with a high sensitivity for detecting patients with non-sustained ventricular tachycardia. CONCLUSIONS: Abnormal signal averaged ECG and echocardiographic variables are associated with potentially malignant ventricular arrhythmias on the Holter recordings in asymptomatic patients with repaired tetralogy of Fallot.

Adult↗