Biomedical subjects

Katerina K Naka

Publications and source records attributed to Katerina K Naka.

10 recordsLinked to original sources

PubMed2006

Long-term clinical outcome of patients treated with beta-brachytherapy in routine clinical practice.

BACKGROUND: Only limited data exist regarding the long-term efficacy of beta-brachytherapy (beta-VBT) in routine clinical practice and the impact of the prolonged (>6 months) combined antiplatelet therapy after beta-VBT. Our aim is to examine the long-term clinical efficacy of routine beta brachytherapy (beta-VBT) followed by indefinite administration of combined antiplatelet therapy in patients at high restenotic risk. METHODS: Sixty-one patients with 65 lesions [de novo: 41, in-stent restenotic (ISR): 24] underwent intracoronary beta-VBT and were followed prospectively. All patients received indefinite administration of aspirin and clopidogrel, underwent routine angiography 6 months later and were followed-up clinically for 43.7 months (range: 32 to 52 months). RESULTS: Acute success was achieved in 60/61 (98.4%) patients. Lesion length was 36.1 (+/-17.6) mm for the de novo and 22.0 (+/-9.8) mm for the ISR (p=0.001). Stents were implanted in 35/41 de novo and 7/24 ISR lesions (p<0.01). Six-month binary restenosis after successful beta-VBT was 35.9% (23/64). During follow-up patients with de-novo lesions who received a new stent during index procedure had a higher incidence of major cardiac events than patients with ISR lesions without a new stent (log rank test, p=0.02). Acute and late thrombotic events were reported at 6 patients, all with de novo lesions and stent implantation. CONCLUSIONS: Beta-VBT plus stenting in de novo lesions is related to an unacceptable high rate of thrombotic complications and clinical restenosis despite prolonged administration of combined antiplatelet therapy. Brachytherapy remains a reasonable option for patients with ISR lesions until full data from large randomized trials comparing drug eluting stents with brachytherapy are available.

Aspirin↗

PubMed2006

Premature ovarian failure, endothelial dysfunction and estrogen-progestogen replacement.

Cardiovascular disease, including coronary artery disease, stroke and peripheral vascular disease, is the leading cause of death among women. Vascular endothelial dysfunction is an early marker of atherosclerosis. Women with premature ovarian failure (or premature menopause) present an increased risk for cardiovascular disease, which might be attributed to the early onset of vascular endothelial dysfunction, associated with sex steroid deficiency. Cyclical estrogen and progestogen therapy has been shown to restore endothelial function in these young women. Further research is required to assess primarily the long-term effects of hormone replacement therapy on cardiovascular and overall prognosis in young women with premature ovarian failure, as well as the effects of different doses, duration and routes of hormone administration in these women.

Adult↗

PubMed2005

Flow-mediated changes in pulse wave velocity: a new clinical measure of endothelial function.

AIMS: To test whether measuring hyperaemic changes in pulse wave velocity (PWV) could be used as a new method of assessing endothelial function for use in clinical practice. METHODS AND RESULTS: Flow-mediated changes in vascular tone may be used to assess endothelial function and may be induced by distal hyperaemia, while endothelium-mediated changes in vascular tone can influence PWV. These three known principles were combined to provide and test a novel method of measuring endothelial function by the acute effects of distal hyperaemia on upper and lower limb PWV (measured by a recently developed method). Flow-mediated changes in upper and lower limb PWV were compared in 17 healthy subjects and seven patients with stable chronic heart failure (CHF), as a condition where endothelial function is impaired but endothelium-independent dilator responses are retained. Corroborative measurements of PWV and brachial artery diameter responses to endothelium-dependent and -independent pharmacological stimuli were performed in a further eight healthy subjects. Flow-mediated reduction of PWV (by 14% with no change in blood pressure) was found in normal subjects but was almost abolished in patients with CHF. PWV responses appear to be inversely related to and relatively greater than brachial artery diameter responses. CONCLUSION: The method may offer potential advantages of practical use and sensitivity over conduit artery diameter responses to measure endothelial dysfunction.

Adult↗

PubMed2005

Predictors of endothelial dysfunction in young women with polycystic ovary syndrome.

CONTEXT: Women with polycystic ovary syndrome (PCOS) may be at increased risk for cardiovascular disease. Endothelial dysfunction is an early marker of atherosclerosis. OBJECTIVES: The objectives of this study were to 1) compare endothelial function in young women with PCOS and regularly menstruating control women, and 2) to identify the determinants of endothelial function and investigate its relationship with body mass index in women with PCOS. DESIGN: This was a cross-sectional study. SETTING: This study was conducted at a tertiary cardiovascular research center. PATIENTS: Sixty-two young women with PCOS (mean age, 22.7 yr) and 17 control women, matched as a group for age and body mass index, were studied. Twenty-three women with PCOS were lean, 21 were overweight, and 18 were obese. MAIN OUTCOME MEASURES: Endothelium-dependent and -independent vascular function was assessed by measuring flow-mediated dilation (FMD) and nitrate-mediated dilation in the brachial artery (diameter change during hand hyperemia and after sublingual glyceryl trinitrate administration, respectively). RESULTS: FMD and nitrate-mediated dilation were significantly lower in PCOS than in control women (reduced by approximately 50 and 25%, respectively; both P < 0.0005). Insulin resistance, total testosterone, and total cholesterol were independent predictors of FMD, accounting for 21, 10, and 9% of the variance, respectively (P < 0.005 for all). A trend of deterioration in FMD from lean to overweight and obese PCOS women was observed, but differences among groups were not statistically significant. CONCLUSIONS: Women with PCOS have significant endothelial dysfunction at an early age (i.e. early 20s), and largely independent of obesity. This suggests that women with PCOS are at increased risk for early onset cardiovascular disease and may gain particular benefit from measures to improve endothelial function.

Adult↗

PubMed2005

Enoxaparin versus tinzaparin in non-ST-segment elevation acute coronary syndromes: results of the enoxaparin versus tinzaparin (EVET) trial at 6 months.

BACKGROUND: We have previously reported significant benefits of using enoxaparin, compared to tinzaparin, in the 7- and 30-day incidence of the composite triple end point of death, myocardial infarction (MI), or recurrent angina in patients with non-ST-segment elevation acute coronary syndromes (NSTACS). In the present study, we aimed to determine whether the observed benefits of enoxaparin were maintained beyond the early phase and report the results of the 6-m follow-up of patients in the EVET study. METHODS: We recruited 438 patients with NSTACS. All patients received oral aspirin and were randomized to also receive enoxaparin, 100 IU/kg subcutaneously twice daily (equivalent to 1 mg/kg twice daily; n = 220), or tinzaparin, 175 IU/kg subcutaneously once daily (n = 218), for up to 7 days. RESULTS: At 6 m, the incidence of the composite triple end point of death, MI, or recurrent angina was lower among patients receiving enoxaparin compared to those receiving tinzaparin (25.5% vs 44.0%, P < .001). A lower incidence of the secondary composite end point of death or MI was also found in the enoxaparin group compared to tinzaparin group (2.7% vs 6.9%, P = .046). The need for revascularization procedures was also lower in the enoxaparin group compared to tinzaparin group (23.2% vs 37.2%, P = .002). CONCLUSIONS: In patients with NSTACS, enoxaparin significantly reduced the rates of recurrent ischemic events and therapeutic procedures in the short term, with sustained benefit at 6 m compared to tinzaparin.

Acute Disease↗

PubMed2004

Impaired endothelial function in young women with premature ovarian failure: normalization with hormone therapy.

Normal menopause is associated with vascular endothelial dysfunction, an early stage of atherosclerosis. The effect of premature ovarian failure (or premature menopause) on endothelial function in young women is unknown. Endothelial function was assessed in 18 women with premature ovarian failure before and after 6 months of hormone therapy and was compared with the endothelial function of 20 age- and body mass index-matched premenopausal women. Brachial artery diameter was measured both during hyperemia (an index of endothelium-dependent vasodilation) and in response to glyceryl trinitrate (an index of endothelium-independent vaso-dilation). Flow-mediated dilation was significantly lower in women with premature ovarian failure at baseline (increase in brachial artery diameter during hyperemia by 3.06 +/- 4.33%) than in control women (increase by 8.84 +/- 2.15%; P < 0.0005). Glyceryl trinitrate-induced vasodilation did not differ between the groups. After hormone therapy for 6 months, flow-mediated dilation was improved in women with premature ovarian failure, increasing by more than 2-fold (7.41 +/- 3.86%; P < 0.005 compared with pretreatment) and reaching normal values (P not significant compared with control women). Glyceryl trinitrate-induced vasodilation did not change after treatment in women with premature ovarian failure. Young women with premature ovarian failure have significant vascular endothelial dysfunction. Early onset of endothelial dysfunction associated with sex steroid deficiency may contribute to the increased risk of cardiovascular disease and mortality in young women with premature ovarian failure. Hormone therapy restores endothelial function within 6 months of treatment.

Adult↗

PubMed2003

Enoxaparin versus tinzaparin in non-ST-segment elevation acute coronary syndromes: the EVET trial.

BACKGROUND: Low-molecular weight heparins have different pharmacokinetic and pharmacodynamic characteristics and may vary in efficacy. We compared the efficacy of enoxaparin with that of tinzaparin in the management of non-ST-segment elevation acute coronary syndromes (NSTACS). METHODS: A total of 438 patients with NSTACS were randomized to receive subcutaneous treatment with enoxaparin, 100 IU/kg twice daily (equivalent to 1 mg/kg twice daily; n = 220), or tinzaparin, 175 IU/kg once daily, (n = 218) for as long as 7 days. The primary composite end point was recurrent angina, myocardial infarction (or reinfarction), or death at day 7. Secondary end points were the primary end point at day 30 and the occurrence of individual events at days 7 and 30. RESULTS: The incidence of the primary end point was 12.3% in the enoxaparin group and 21.1% in the tinzaparin group (P =.015). At day 7, the rate of recurrent angina was lower with enoxaparin than with tinzaparin (11.8% vs 19.3%). At day 30, the incidences of the composite end point, recurrent angina, and myocardial infarction were also lower with enoxaparin, 17.7% vs 28.0% (P =.012), 17.3% vs 26.1% and 0.5% vs 2.8%, respectively. The rate of revascularization was lower in the enoxaparin group, 8.6% vs 17.9% (P =.010) at day 7 and 16.4% vs 26.1% (P =.019) at day 30. Rates of bleeding complications were similar in the 2 treatment groups. CONCLUSIONS: This study indicates a benefit of enoxaparin (100 IU/kg twice daily) as compared with tinzaparin (175 IU/kg once daily) in the treatment of patients with NSTACS, which is sustained for at least 30 days.

Aged↗

PubMed2003

Transient intraventricular conduction delay associated with concurrent intake of propafenone and antineoplastic agents.

An 82-year old man was admitted with acute pulmonary edema. Myocardial ischemia and electrolyte abnormalities were excluded and he responded promptly to frusemide, nitrates and morphine. On admission, the duration of the QRS interval was markedly abnormal at 240 ms with a nonspecific intraventricular conduction defect pattern, of left bundle branch block type. This finding was not present three weeks prior to his admission, and was felt to be the result of drug interaction between propafenone and antineoplastic agents, as evidenced by resolution of the clinical and electrocardiographic picture after discontinuation of these agents.

Acute Disease↗

PubMed2002

Arterial distensibility: acute changes following dynamic exercise in normal subjects.

The time course of acute changes in large artery distensibility immediately and for 60 min following maximum treadmill exercise in normal subjects was characterized by simultaneously measuring upper and lower limb pulse wave velocity (PWV). A new oscillometric technique was used, which has proven to be sensitive to changes in distensibility induced by acute changes in vascular tone independently of blood pressure. The observed changes in PWV are attributable to changes in vascular tone corresponding to recovery from a systemic net constrictor response and a local net dilator response to exercise with persisting postexercise vasodilatation. They are inadequately explained by associated changes in blood pressure and cannot be attributed to changes in heart rate or viscosity. Modeled as a system of n coupled linear differential equations, the minimum (and adequate) order required to reproduce these patterns was n = 1 for the upper and n = 2 for the exercising lower limb. The economy of the solution suggests entrainment among the multiple interactive mechanisms governing vasomotor control.

Adolescent↗

PubMedDate not supplied

Radiofrequency catheter ablation for electrical storm in a patient with dilated cardiomyopathy.

We report a case of successful radiofrequency catheter ablation in a patient with dilated cardiomyopathy, who presented with multiple, haemodynamically poorly tolerated episodes of monomorphic ventricular tachycardia, resistant to antiarrhythmic drug treatment. The ablation procedure consisted of focal ablation of three mapped left ventricular sites, using pace and activation mapping. Additional linear ablation lesions were created across these sites. After the procedure, the patient remained free of tachycardia episodes and seven days post-ablation he underwent implantation of a cardioverter-defibrillator. During a twelve-month follow-up period, the patient has remained free of monomorphic ventricular tachycardia episodes. Radiofrequency catheter ablation is feasible in electrical storm, using conventional mapping techniques, even in haemodynamically unstable tachycardias.

Aged↗