Biomedical subjects

Georgios I Papaioannou

Publications and source records attributed to Georgios I Papaioannou.

6 recordsLinked to original sources

PubMed2004

Brachial artery reactivity in asymptomatic patients with type 2 diabetes mellitus and microalbuminuria (from the Detection of Ischemia in Asymptomatic Diabetics-brachial artery reactivity study).

Microalbuminuria is a novel atherosclerotic risk factor in patients with type 2 diabetes mellitus (DM) and predicts future cardiovascular events. Endothelial dysfunction and systemic inflammation have been proposed as common links between microalbuminuria and cardiovascular disease. However, no study has assessed the relation between microalbuminuria and vascular dysfunction as measured by brachial artery reactivity (BAR) in DM. We evaluated 143 patients (85 men; mean age 60.0 +/- 6.7 years) with DM (mean duration 8.2 +/- 7.4 years) enrolled in the Detection of Ischemia in Asymptomatic Diabetics study. Subjects were categorized as those with microalbuminuria (ratio of urinary albumin to creatinine 30 to 299 microg/mg creatinine, n = 28) and those with normoalbuminuria (ratio of urinary albumin to creatinine 0 to 29.9 microg/mg creatinine, n = 115). High-resolution ultrasound BAR testing was used to measure endothelium-dependent and endothelium-independent vasodilations. C-reactive protein was measured as a marker of systemic inflammation. Patients with microalbuminuria and normoalbuminuria had similar baseline characteristics, with the exception that those with microalbuminuria had a longer duration of DM (p = 0.03). Endothelium-dependent vasodilation at 1 minute (p = 0.01) and endothelium-independent vasodilation at 3 minutes (p = 0.007) were significantly less in patients with microalbuminuria. In addition, 96% of patients with microalbuminuria and 76% of those with normoalbuminuria had impaired endothelium-dependent vasodilation (<8%, p = 0.01). Microalbuminuria was an independent predictor of endothelium-dependent vasodilation in the entire cohort (p = 0.045) and after excluding patients on hormone replacement therapy (p = 0.01). Levels of C-reactive protein were significantly higher in patients with microalbuminuria than in those with normoalbuminuria (p = 0.02). We conclude that in DM the presence of microalbuminuria is associated with impaired endothelium-dependent and endothelium-independent vasodilations of the brachial artery and a higher degree of systemic inflammation. In addition, microalbuminuria is an independent predictor of endothelial dysfunction in asymptomatic patients with DM, especially in the absence of hormone replacement therapy.

Age Factors↗

PubMed2004

Usefulness of electrocardiographic-gated stress technetium-99m sestamibi single-photon emission computed tomography to differentiate ischemic from nonischemic cardiomyopathy.

The noninvasive differentiation between ischemic and nonischemic cardiomyopathy is frequently difficult. We examined the clinical value of stress electrocardiographic gated (ECG-gated) single-photon emission computed tomography (SPECT) to identify ischemic cardiomyopathy and detect coronary artery disease (CAD) in 164 patients without known CAD, ejection fraction < or =40% by ECG-gated SPECT, and subsequent coronary angiography. Summed stress, rest, and difference scores were measured from the SPECT studies, and regional wall motion variance was calculated from the ECG-gated images. Sensitivity and 95% confidence intervals for the diagnosis of ischemic cardiomyopathy and for detection of any CAD (>50% diameter stenosis) were estimated using previously defined cutoffs for summed stress score and regional wall motion variance. For the diagnosis of ischemic cardiomyopathy, sensitivity of stress SPECT (summed stress score >8) was 87% (95% confidence interval [CI] 78 to 95), with a specificity of 63% (95% CI 60 to 82). The addition of wall motion information (summed stress score >8 or regional wall motion variance >0.114) increased sensitivity to 88% (95% CI 80 to 96) and decreased specificity to 45% (95% CI 35 to 55). If reversibility was also taken into account (summed stress score >8, regional wall motion variance >0.114, or summed difference score >0), sensitivity further increased to 94% (95% CI 88 to 100) and specificity decreased to 32% (95% CI 23 to 41). For detection of any CAD, the combined approach using stress perfusion, reversibility, and region of wall motion had a sensitivity of 94% (95% CI 89 to 99) and a specificity of 45% (95% CI 35 to 57). Therefore, ECG-gated SPECT is very sensitive for detection of ischemic cardiomyopathy and CAD among patients with moderate to severe systolic dysfunction.

Adult↗

PubMed2004

Treating hypothyroidism improves endothelial function.

Hypothyroidism patients have increased cardiovascular risk, although the mechanism is not defined. Endothelial dysfunction may initiate atherosclerosis, is present in patients with hypothyroidism, and therefore may link hypothyroidism and vascular disease. We are unaware of studies examining the effect of thyroid replacement therapy on endothelial function in hypothyroid patients. The present study examined the effect of treatment of hypothyroidism on brachial artery reactivity. Consequently, we measured endothelium-dependent (EDV) and endothelium-independent (EIV) vasodilation using brachial artery ultrasonography in 8 hypothyroid patients (5 men, mean age 48.9 +/- 5.5 years; mean thyrotropin [TSH] 49.0 +/- 37.0 mIU/L) before and after thyroxine treatment. Thyroxine treatment reduced average TSH to 2.9 +/- 0.5 mIU/L and improved EDV (8.0% +/- 4.4% v 3.4% +/- 2.5%, P <.05), whereas EIV was unchanged (20.3% +/- 6.1% v 19.2% +/- 9.4%, P = not significant [NS]). Thyroxine treatment did not alter serum lipids. Thyroid replacement therapy improves endothelium-dependent vascular reactivity in patients with hypothyroidism irrespective of lipid changes.

Adult↗

PubMed2002

Ineffective ICD therapy due to excessive alcohol and exercise.

A 49-year-old man with dilated cardiomyopathy and an ICD received eight unsuccessful shocks for a single episode of ventricular tachycardia after excessive alcohol intake and exercise. The patient had low defibrillation thresholds just 8 days prior to his event during a routine 6-week postimplant electrophysiological study. Defibrillation threshold testing after his incident confirmed the low energy requirement for ventricular tachycardia termination. A previous animal study reported that intravenous ethanol elevates the defibrillation energy in a dose dependent manner. However, a recent study in humans showed that modest alcohol intake had no effect on defibrillator thresholds. This case report supports the animal data and suggests that excessive alcohol consumption can cause a life-threatening situation in ICD patients.

Alcohol Drinking↗

PubMedDate not supplied

Value of peripheral vascular endothelial function in the detection of relative myocardial ischemia in asymptomatic type 2 diabetic patients who underwent myocardial perfusion imaging.

BACKGROUND: Endothelial dysfunction precedes overt atherosclerosis and is present in patients with type 2 diabetes mellitus (T2DM). Myocardial perfusion imaging (MPI) is an effective method of detection of coronary artery disease (CAD); however, the relationship between endothelial function and MPI in asymptomatic patients with T2DM has not been examined. METHODS AND RESULTS: This study used a subset of the population from the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study. Endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation (EIV) were measured by use of brachial artery ultrasonography in 75 asymptomatic patients with T2DM (56 men; mean age, 58.6 +/- 6.4 years; mean duration of diabetes, 8.4 +/- 7.5 years) who underwent adenosine MPI. Of the patients, 15 (20%) had evidence of relative ischemia (MPI(+)) whereas 60 (80%) had a normal study (MPI(-)). Both EDV (3.5% +/- 3.7% vs 4.5% +/- 6.6%, P = not significant) and EIV (15.1% +/- 7.5% vs 16.8% +/- 8.4%, P = not significant) were similar in the 2 groups. On the basis of a receiver-operator analysis, an EDV response of 8% was selected as a cut point, with a negative predictive value of 93% (13/14 subjects with EDV >or=8% were MPI(-)). CONCLUSIONS: Endothelial function in asymptomatic patients with T2DM is not associated with the presence of relative myocardial ischemia by MPI; however, an EDV of 8% or greater has a high negative predictive value for the exclusion of CAD.

Adult↗

PubMedDate not supplied

Risk assessment by myocardial perfusion imaging for coronary revascularization, medical therapy, and noncardiac surgery.

Stress myocardial perfusion imaging (MPI) has become an important tool in risk stratification of patients with known coronary artery disease. A normal myocardial perfusion scan has a high negative predictive value and is associated with low annual mortality rate (< 1%). Patients with extensive ischemia (> 20% of the left ventricle), defects in more than 1 coronary vascular territory, transient or persistent left ventricular cavity dilation, and ejection fraction less than 45% have a high annual mortality rate (> 3%). Those patients should undergo coronary revascularization whenever feasible, as the cardiac event rate increases in proportion to the magnitude of the jeopardized myocardium. Stress MPI can be used to demonstrate ischemia in patients with symptoms early after coronary artery bypass surgery (< 5 years) or in those without symptoms late (>/= 5 years) after coronary artery bypass surgery. With respect to patients who underwent percutaneous interventions, stress MPI can help detect in-stent restenosis early after the intervention (3-6 months) or assess the progression of native coronary disease afterward. Since preliminary data suggest that a reduction in the perfusion defect size may translate to a reduction of coronary events, stress MPI can help assess the efficacy of medical management of coronary disease. Finally, stress MPI is indicated for perioperative cardiac risk stratification for noncardiac surgery in patients with intermediate risk predictors (mild angina, prior myocardial infarction or heart failure symptoms, diabetes mellitus, renal insufficiency) and poor functional capacity or in those who undergo high-risk surgery with significant implications in further preoperative management.

Algorithms↗