Phenotyping vs. genotyping for prediction of clopidogrel efficacy and safety: the PEGASUS-PCI study.

BACKGROUND: Prognostic values of genotyping and phenotyping for assessment of clopidogrel responsiveness have been shown in independent studies. OBJECTIVES: To compare different assays for prediction of events during long-term follow-up. METHODS: In this prospective cohort study polymorphisms of CYP2C19*2 and CYP2C19*17 alleles, vasodilator-stimulated phosphoprotein phosphorylation (VASP) assay, multiple electrode aggregometry (MEA), cone and platelet analyser (CPA) and platelet function analyser (PFA-100) were performed in 416 patients undergoing percutaneous coronary intervention. The rates of events were recorded during a 12-month follow-up. RESULTS: Platelet aggregation by MEA predicted stent thrombosis (2.4%) better (c-index = 0.90; P < 0.001; sensitivity = 90%; specificity = 83%) than the VASP assay, CPA or PFA-100 (c-index < 0.70; P > 0.05; sensitivity < 70%; specificity < 70% for all) or even the CYP2C19*2 polymorphism (c-index < 0.56; P > 0.05; sensitivity = 30%; specificity = 71%). Survival analysis indicated that patients classified as poor responders by MEA had a substantially higher risk of developing stent thrombosis or MACE than clopidogrel responders (12.5% vs. 0.3%, P < 0.001, and 18.5% vs. 11.3%, P = 0.022, respectively), whereas poor metabolizers (CYP2C19*1/*2 or *2/*2 carriers) were not at increased risks (stent thrombosis, 2.7% vs. 2.5%, P > 0.05; MACE, 13.5% vs. 12.1%, P = 0.556). The incidence of major bleedings (2.6%) was numerically higher in patients with an enhanced vs. poor response to clopidogrel assessed by MEA (4% vs. 0%) or in ultra-metabolizers vs. regular metabolizers (CYP2C19*17/*17 vs. CYP2C19*1/*1; 9.5% vs. 2%). The classification tree analysis demonstrated that acute coronary syndrome at hospitalization and diabetes mellitus were the best discriminators for clopidogrel responder status. CONCLUSIONS: Phenotyping of platelet response to clopidogrel was a better predictor of stent thrombosis than genotyping.

Inhomogeneous vasomotor effects of moderate selective and non-selective endothelin-receptor blockade in stable coronary artery disease.

OBJECTIVE: To explore the morphological and functional effect of selective and non-selective endothelin (ET)-receptor blockade in coronary artery disease (CAD). DESIGN: Prospective randomised controlled trial. SETTING: University hospital. PATIENTS: 26 patients with stable CAD. INTERVENTIONS: Intracoronary infusion (30 minutes) of the ET-A receptor blocker BQ-123 (40 nmol/min, group A, n = 13) alone or with the ET-B receptor blocker BQ-788 (10 nmol/min, group AB, n = 13) as well. MAIN OUTCOME MEASURES: Fractional flow reserve (FFR), coronary flow reserve (CFR) and intramyocardial resistance (IMR) by PressureWire, mean arterial blood pressure (MAP), minimal lumen diameter (MLD) and average angiographic lumen diameter (mean LD) of the target vessel before and after intracoronary infusion of ET antagonists. Concentrations of C-terminal pro-endothelin-1 (CT-proET1) in arterial blood were determined before and after infusion. RESULTS: Mean MLD, mean LD, FFR, CFR, IMR and MAP remained unaffected by ET-receptor blockade in both groups; their changes were comparable. Concentrations of CT-proET-1 increased by 6.2 (SD 5.9) pmol/l (95% CI 1.2 to 11.1 pmol/l; p = 0.022) in group A and by 4.1 (SD 4.3) pmol/l (95% CI 1.1 to 7.2 pmol/l; p = 0.014) in group AB. CONCLUSIONS: We found a broad variety of individual haemodynamic responses to ET-receptor antagonists with an overall neutral effect after an infusion period of 30 minutes despite an overall effective blockade of ET-receptors. Prolonged infusion time may be needed to cause a more distinct vasomotor response. TRIAL REGISTRATION NUMBER: NCT00427232.

Hemodynamic effects of a continuous infusion of levosimendan in critically ill patients with cardiogenic shock requiring catecholamines.

BACKGROUND: Levosimendan, a novel inodilator, has been shown to improve hemodynamic function in patients with decompensated heart failure with preserved arterial blood pressure. Data on its use in patients with cardiogenic shock are rare. The present series describes the 24-h hemodynamic effects of levosimendan as add-on therapy in desperately ill patients with cardiogenic shock requiring catecholamines. METHODS: Ten patients with cardiogenic shock received levosimendan as continuous infusion of 0.1 microg kg(-1) min(-1) for 24 h. The patients were otherwise unselected. Hemodynamic measurements were routinely performed at baseline (time 0) and at 1, 8, 16 and 24 h after start of levosimendan (LS) using a Swan-Ganz thermodilution catheter. RESULTS: During the levosimendan infusion there was a significant increase in cardiac index from 1.8 +/- 0.4 to 2.4 +/- 0.6 L*min-1*m-2 (P = 0.023) and a significant decrease in systemic vascular resistance from 1559 +/- 430 to 1109 +/- 202 dyn*s*cm-5 (P = 0.001), respectively. Changes in catecholamine dose, and in systolic and diastolic blood pressure were not significant. Given the individual response to LS, 8/10 patients showed an increase in left ventricular stroke work index under reduced or roughly unchanged preload conditions after 8 h. CONCLUSION: This series shows that a LS infusion is feasible and able to improve hemodynamics in severely compromized, critically ill patients with cardiogenic shock requiring catecholamine therapy. Its potential advantages when compared with other inotropes are unclear. To clarify the potential role of LS in this clinical setting randomized controlled trials on hemodynamic and mortality endpoints are needed.

Endothelial dysfunction in patients with polycythaemia vera.

Patients with polycythaemia vera (PV) are at increased risk of developing arterial and venous thromboembolic complications. We investigated whether endothelium-dependent, flow-mediated vasodilatation (FMD) is impaired in PV patients without clinical evidence of artery disease as observed in patients with conventional cardiovascular risk factors. FMD and endothelium-independent, nitroglycerine-induced vasodilatation (NMD) were assessed using high-resolution ultrasound in the brachial artery of 20 patients with PV and 20 sex- and age-matched control subjects (CTL). FMD was markedly impaired in PV patients compared with CTL (7.6 +/- 2.9% versus 11.6 +/- 5.7%, P = 0.009) whereas NMD was similar in both study groups. The impairment of FMD was independently related to the presence of PV (r = -0.434, P = 0.009) and vessel size (r = -0.107, P = 0.038) but was not related to haematocrit values and platelet counts. The results demonstrate that PV is associated with endothelial dysfunction in the pre-clinical phase of arterial disease. However, the precise mechanisms by which PV leads to this altered vascular reactivity remain unclear.

Amiodarone versus diltiazem for rate control in critically ill patients with atrial tachyarrhythmias.

OBJECTIVE: To compare the rate-lowering effect of diltiazem and two amiodarone regimens in critically ill patients with recent-onset atrial tachyarrhythmias. DESIGN: Prospective, randomized, controlled study. SETTING: Medical cardiologic intensive care unit in a university hospital. PATIENTS: Sixty critically ill patients (Acute Physiology and Chronic Health Evaluation [APACHE] III score 70 +/- 30, age 67 +/- 10 yrs). INTERVENTIONS: Patients with atrial fibrillation (n = 57), atrial flutter (n = 2), or atrial tachycardia (n = 1, and a heart rate consistently >120 beats/min over 30 mins were randomly assigned to one of three intravenous treatment regimens. Group 1 received diltiazem in a 25-mg bolus followed by a continuous infusion of 20 mg/hr for 24 hrs, group 2 received amiodarone in a 300-mg bolus, and group 3 received amiodarone in a 300-mg bolus followed by 45 mg/hr for 24 hrs. MEASUREMENTS AND MAIN RESULTS: The primary study end point was a >30% rate reduction within 4 hrs. The secondary study end point was a heart rate <120 beats/min (a patient was considered to have uncontrolled tachycardia if heart rate was >120 beats/min 4 hrs after study drug). The primary study end point was achieved in 14/20 (70%), 11/20 (55%), and 15/20 (75%) of patients in groups 1, 2, and 3, respectively (chi2 = 1.95, p =.38). Uncontrolled tachycardia was more frequently observed in group 2 (0/20, 9/29 [55%], and 1/20 [5%] of patients in groups 1, 2, and 3, respectively; chi2 = 17, p =.00016). In patients achieving tachycardia control, diltiazem showed a significantly better rate reduction (p =.0001 group 1 vs. group 3, p =.0001 over time; p =.0001 group 1 vs. group 2, p =.001 over time) when compared with the amiodarone groups. Premature drug discontinuation due to hypotension was required significantly more often in group 1 (6/20 [30%], 0/20, and 1/20 [5%] for groups 1, 2, and 3, respectively; chi2 = 10, p =.01). CONCLUSION: Sufficient rate control can be achieved in critically ill patients with atrial tachyarrhythmias using either diltiazem or amiodarone. Although diltiazem allowed for significantly better 24-hr heart rate control, this effect was offset by a significantly higher incidence of hypotension requiring discontinuation of the drug. Amiodarone may be an alternative in patients with severe hemodynamic compromise.

Effects of endothelin a receptor blockade on endothelial function in patients with chronic heart failure.

BACKGROUND: Chronic heart failure (CHF) is associated with impaired endothelium-dependent vasodilation and increased basal vascular tone due, in part, to elevated endothelin-1 plasma levels. In the present study, we investigated whether a reduction of vascular tone using an endothelin A receptor blocker attenuates the impairment of endothelium-dependent, flow-mediated vasodilation (FMD). METHODS AND RESULTS: Twenty-one patients with CHF randomly received either the endothelin A receptor blocker LU 135252 (30 mg/d, n=7; 300 mg/d, n=7) or a placebo (n=7). Using high-resolution ultrasound, FMD and endothelium-independent, nitroglycerin-induced dilation of the brachial artery were assessed at baseline in the 21 patients with CHF and in 11 controls and after 3 weeks treatment in the 21 patients with CHF. FMD at baseline was impaired in all 21 patients with CHF (3.2+/-2%) when compared with the 11 controls (9.7+/-4.9%; P=0.0005). In comparison with baseline, FMD significantly improved after 3 weeks of treatment with LU 135252 in all 14 patients receiving it (from 3.0+/-2.0% to 4.9+/-2.9%; P=0.04), but FMD remained unchanged with placebo. Subgroup analysis, according to different dosages, revealed a significant increase of FMD compared with baseline (from 2.4+/-1.5% to 5.5+/-2.4%; P=0.03) in the patients treated with the low-dose (30 mg/d), whereas a high dose of 300 mg/d failed to increase FMD significantly. Improvement in the high-dose group, however, may have been masked by reduced vasodilator capacity due to a significant increase in vessel size (from 4.8+/-0.4 to 5.1+/-0.7 mm; P=0.03). CONCLUSIONS: These results suggest that endothelin A receptor blockade improves FMD in CHF patients.

Successful emergency percutaneous cardiopulmonary support during coronary intervention in an 80-year old patient.

In an 80-year old patient with acute coronary syndrome emergency institution of stand-by percutaneous cardiopulmonary support (PCPS; Bio-Medicus; Medtronic Inc, Minneapolis MN) for hemodynamic collapse in the cardiac catheterization laboratory resulted in successful hemodynamic stabilization and enabled safe performance of a complex coronary intervention. Weaning from PCPS was effectuated after 4 hours total extracorporal circulation time. Despite development of a systemic inflammatory response syndrome and prolonged weaning from mechanical ventilation the patient could be discharged from the intensive care unit after 14 days and eventually from hospital another 28 days later with favorable outcome. Although an increased complication rate with prolonged rehabilitation has to be taken into account percutaneous cardiopulmonary support may constitute a live-saving option even in selected elderly patients.

Effects of successful parathyroidectomy on altered arterial reactivity in patients with hypercalcaemia: results of a 3-year follow-up study.

OBJECTIVE: Serum calcium was found to be an independent, prospective risk factor for myocardial infarction. We have previously shown that altered arterial reactivity in the course of primary hyperparathyroidism, a disease characterized by hypercalcaemia, may predominantly involve the arterial media and not the endothelium as observed in patients with various stages of atherosclerosis. The present study was performed to test whether successful parathyroidectomy can improve vascular reactivity in patients with primary hyperparathyroidism. SUBJECTS AND DESIGN: Endothelium-dependent, flow-mediated and endothelium-independent, nitroglycerin-induced dilatation were assessed by brachial artery ultrasound (7 MHz) in 18 patients with primary hyperparathyroidism (mean +/- SD; age, 55.1 +/- 12.6) prior to and 3 years after successful parathyroidectomy. RESULTS: Parathyroidectomy resulted in significant decreases of PTH (242 +/- 186 vs. 34 +/- 24 ng/l, P = 0. 0001) and serum calcium levels (2.8 +/- 0.3 vs. 2.4 +/- 0.1 mm/l, P = 0.00001) and in an increase of serum phosphate levels (0.78 +/- 0. 23 vs. 1.17 +/- 0.18 mm/l, P = 0.00001). However, normalization of hormone and electrolyte levels did not lead to an improvement of flow-mediated dilatation (12.1 +/- 3.1 vs. 11.0 +/- 5.4&, P = 0.49) or nitroglycerin-induced dilatation (12.5 +/- 3.1 vs. 13.2 +/- 6.8%, P = 0.68) within the follow-up period. No changes were observed with respect to the risk factor profile, vessel size and blood flow. CONCLUSION: These data suggest that restoration of normocalcaemia by parathyroidectomy cannot improve vascular reactivity in patients with primary hyperparathyroidism but may prevent further progression of vascular disease within this period of time.

Transient swallow syncope during periods of hypoxia in a 67-year-old patient after self-extubation.

OBJECTIVE: To describe the case of an adult patient with swallow syncope after bypass surgery, possibly related to hypoxia. DESIGN: Case report. SETTING: University hospital, medical-cardiologic intensive care unit. PATIENT: A 67-yr-old patient after second aortocoronary bypass operation for unstable angina. MAIN RESULTS: After the patient managed to extubate himself, he was in a borderline respiratory condition with an oxygen mask. When drinking for the first time after extubation, asystole was observed coincidentally with interruption of oxygen insufflation. During the next days, similar events occurred during food ingestion or when drinking liquids after a fall of oxygen saturation. The bradyarrhythmia was readily reversible on administration of atropine and ventricular backup pacing via temporary pacing wires. After normalization of gas exchange, no more episodes of swallowing-associated asystole were observed and the patient was discharged without a permanent pacemaker. There was no esophageal or gastrointestinal disease. Pre- and postoperative PR and QRS durations were normal. CONCLUSION: Extrinsic and transient mechanisms, rather than intrinsic conduction system disease, seem to have been operative in this case. It is suggested that hypoxia reinforced the vagal pharyngocardiac reflex as described in pediatric patients.

Effects of vitamin E on chronic and acute endothelial dysfunction in smokers.

OBJECTIVES: The aims of this study were to determine whether chronic or acute impairment of flow mediated vasodilation (FMD) in the brachial artery of smokers can be restored or preserved by the antioxidant vitamin E. BACKGROUND: Transient impairment of endothelial function after heavy cigarette smoking and chronic endothelial dysfunction in smokers result at least in part from increased oxidative stress. METHODS: We studied 22 healthy male smokers (mean +/- SD, 23 +/- 9 cigarettes per day) randomly assigned to receive either 600 IU vitamin E per day (n = 11, age 28 +/- 6 years) or placebo (n = 11, age 27 +/- 6 years) for four weeks and 11 age-matched healthy male nonsmokers. Flow mediated vasodilation and endothelium-independent, nitroglycerin-induced dilation were assessed in the brachial artery using high resolution ultrasound (7.5 MHz) at baseline and after therapy. Subjects stopped smoking 2 h before the ultrasound examinations. At the end of the treatment period, a third scan was obtained 20 min after smoking a cigarette (0.6 mg nicotine, 7 mg tar) to estimate transient impairment of FMD. RESULTS: Flow mediated vasodilation at baseline was abnormal in the vitamin E (5.3 +/- 3.8, p < 0.01) and in the placebo group (6.4 +/- 3.5, p < 0.05) compared with nonsmoking controls (11.6 +/- 4.7). Using a two-way repeated measures analysis of variance (ANOVA) to examine the effects of vitamin E on FMD, we found no effect for the grouping factor (p = 0.5834) in the ANOVA over time but a highly significant difference with respect to time (p = 0.0065). The interaction of the time factor and the grouping factor also proved to be significant (p = 0.0318). Flow mediated vasodilation values remained similar after treatment for four weeks in both groups but declined faster after smoking a cigarette in subjects taking placebo compared with those receiving vitamin E (p values from successive differences for the time/group factor: 0.0001/0.0017). The transient attenuation of FMD (calculated as the percent change in FMD) was related to the improvement of the antioxidant status, estimated as percent changes in thiobarbituric acid-reactive substances (r = -0.67, p = 0.0024). Nitroglycerin-induced dilation did not differ between study groups at baseline or after therapy. CONCLUSIONS: These results demonstrate that oral supplementation of vitamin E can attenuate transient impairment of endothelial function after heavy smoking due to an improvement of the oxidative status but cannot restore chronic endothelial dysfunction within four weeks in healthy male smokers.

IV milrinone for cardiac output increase and maintenance: comparison in nonhyperdynamic SIRS/sepsis and congestive heart failure.

OBJECTIVE: To characterize the effect of the phosphodiesterase inhibitor (PDEI) milrinone in adult patients with a non-hyperdynamic condition during the course of the systemic inflammatory response syndrome (SIRS) or sepsis when compared with patients with congestive heart failure (CHF). PDEIs are potent inhibitors of cytokine production and expression. We hypothesized that there might be an outstanding beneficial effect of PDEIs in the setting of SIRS/sepsis. DESIGN: Prospective, open labeled, protocol-driven pilot study. PATIENTS: Nine patients with a nonhyperdynamic hemodynamic condition during SIRS/sepsis (group 1) and seven patients with CHF (group 2) requiring inotropic support. All patients were having heart disease. All patients had a combination of various catecholamines at the time of inclusion in the study and had received fluid resuscitation to an extent that left ventricular stroke work index (LVSWI) did not increase further. INTERVENTION: Milrinone infusion at a rate of 0.5 microg/kg per min in addition to preexisting catecholamine therapy. MEASUREMENTS AND RESULTS: Measurements of cardiac index (CI; thermodilution) and calculation of vascular resistance and LVSWI was done every 8 h for at least 40 h during milrinone infusion. CI and LVSWI significantly increased in both groups (p < 0.001 and p = 0.006, respectively). There were no significant differences between groups in these parameters (p > 0.11 and p > 0.13, respectively). The LVSWI increase occurred while there was a decrease in pulmonary capillary wedge pressure, suggesting a true and comparable improvement in cardiac function relatively independent of loading conditions. Preexisting catecholamines had to be increased in both groups (NS). Milrinone had to be discontinued in one patient due to hypotension. CONCLUSION: Milrinone administration is feasible in selected patients with a non-hyperdynamic condition during SIRS/sepsis and with preexisting heart disease. Under the conditions of this study, milrinone was no better in terms of CI and LVSWI maintenance in septic cardiac dysfunction when compared with CHF. These results do not necessarily extend to other cohorts with no preexisting heart disease.

Additional benefit of vitamin E supplementation to simvastatin therapy on vasoreactivity of the brachial artery of hypercholesterolemic men.

OBJECTIVES: The aim of this study was to determine whether the combination of lipid-lowering therapy and vitamin E supplementation improves peripheral endothelial function and whether it is more effective than lipid-lowering therapy alone. BACKGROUND: Endothelium-dependent vasodilation is impaired in coronary and peripheral arteries of patients with hypercholesterolemia. Coronary endothelial function has been shown to improve under lipid-lowering and antioxidant therapy, but the effect of additive vitamin E supplementation in the brachial artery is unknown. METHODS: Seven patients with hypercholesterolemia (mean+/-SD; age 51+/-10 yr) were studied. Endothelium-dependent, flow-mediated dilation (FMD) and endothelium-independent nitroglycerin-induced dilation (NMD) were assessed in the brachial artery using high resolution ultrasound 1) at baseline (BL I), 2) after 8 weeks of simvastatin (20 mg) and vitamin E (300 IU) therapy (Comb I), 3) after withdrawal of vitamin E for 4 weeks (Statin), 4) after therapy as in #2 for 4 weeks (Comb II) and 5) after withdrawal of both drugs for 4 weeks (BL II). RESULTS: Combined simvastatin and vitamin E therapy reduced total cholesterol (Comb I vs. BL I: 276+/-22 vs. 190+/-14 mg/dl, p < 0.0001) and low-density lipoprotein (LDL)-C (197+/-22 vs. 106+/-22 mg/dl, p < 0.00001), augmented alpha tocopherol levels normalized to LDL (12.2+/-4.1 vs. 4.9+/-0.9 microg alpha-T/100 mg% LDL-C, p < 0.01) and resulted in significant improvements in FMD (16.4+/-4.7 vs. 4.9+/-2.5%, p < 0.001) as well as NMD (17.9+/-4.3 vs. 11.2+/-2.8%, p < 0.01). The ratio of FMD to NMD (0.92+/-0.17 vs. 0.46+/-0.24%, p < 0.05) also increased under combination therapy, indicating a greater improvement of FMD than that of NMD. After withdrawal of vitamin E, both FMD (Comb I vs. Statin: 16.4+/-4.7 vs. 7.9+/-4.7%, p < 0.01) and NMD (17.9+/-4.3 vs. 10.9+/-4.5%, p < 0.05) decreased significantly such that simvastatin alone only tended to improve FMD and did not change NMD. Results under combination therapy (Comb II vs. BL II) were reproducible. CONCLUSIONS: Combined vitamin E and simvastatin therapy leads to an improvement of FMD and NMD in the brachial artery of patients with hypercholesterolemia. The improvement of FMD is more pronounced after combination therapy than after lipid-lowering therapy alone, similar to previous findings in the coronary circulation.

Impairment of endothelium-independent vasodilation in patients with hypercalcemia.

OBJECTIVE: Patients with primary hyperparathyroidism (PHPT) and/or hypercalcemia are at increased risk for myocardial ischemia. Whether PHPT is associated with altered endothelium-dependent dilation, vascular smooth muscle cell function, or both is unknown. This study was performed to test the hypothesis that endothelium-dependent, flow-mediated dilation (FMD) and/or endothelium-independent, nitroglycerin-induced dilation (NMD) is impaired in the preclinical phase of vascular disease in patients with PHPT. METHODS: Twenty-six PHPT patients (mean +/- SD; age 55 +/- 15 y, serum calcium 3.00 +/- 0.37 mmol/l, serum phosphate 0.79 +/- 0.21 mmol/l, iPTH 249 +/- 262 pg/ml) with no evidence of coronary artery disease (CAD) as well as 26 normocalcemic control subjects (CTL; age 51 +/- 12 y) were studied. FMD following reactive hyperemia and NMD after 0.8 mg nitroglycerin (NTG) were assessed in the brachial artery by using high resolution ultrasound (7 MHz). RESULTS: NMD was impaired in PHPT patients compared to CTL (11.9 +/- 3.9% vs. 15.6 +/- 5.7%; p = 0.012). FMD was similar in both study groups (11.6 +/- 4.6% vs. 12.6 +/- 4.9; NS). The ratio of FMD to NMD was significantly different between PHPT patients and CTL (0.98 +/- 0.19 vs 0.81 +/- 0.25, p = 0.0009). On multiple stepwise regression analysis serum calcium was independently associated with the FMD/NMD ratio (r = 0.34, p = 0.017). CONCLUSIONS: Endothelium-independent vasodilation is impaired in PHPT patients without clinical evidence of coronary artery disease compared to normocalcemic CTL, while endothelium-dependent dilation was similar in both study groups. Thus, altered arterial reactivity in the course of PHPT may predominantly involve the arterial media and not the endothelium as observed previously in patients with various stages of atherosclerosis.

Relation of hemodynamic variables to augmentation of left anterior descending coronary flow by intraaortic balloon pulsation in coronary artery disease.

Recent studies suggest prophylactic intraaortic balloon-pulsation (IABP) in patients undergoing coronary reperfusion therapy. However, variable effects of IABP on coronary blood flow are reported. It is suggested that augmentation of coronary flow is more effective in patients with a compromised hemodynamic status, which might have potential relevance in selecting IABP treatment in patients undergoing reperfusion therapy.

Documented sudden onset of pseudothrombocytopenia.

A 66-year-old male patient was hospitalized for severe heart failure. Within 3 days after admission his platelet count dropped from 148 x 10(9)/l to 3 x 10(9)/l. Pseudothrombocytopenia was diagnosed based on the platelet count of 3 x 10(9)/l in K3-EDTA anticoagulated blood as opposed to 110 x 10(9)/l in sodium citrate. Platelet reactive antibodies were not detectable. To the best of our knowledge, this is the first report of a documented onset of pseudothrombocytopenia.

Systemic endothelial dysfunction is related to the extent and severity of coronary artery disease.

Flow-mediated vasodilation (FMD) of systemic arteries, a non-invasive parameter of endothelial function, is correlated with cardiovascular risk factors. The relationship between FMD and morphologically and clinically evident coronary artery disease has not been described. This study was performed to test the hypothesis that an impairment of FMD in the brachial artery is related to the presence and/or extent and severity of coronary artery disease (CAD). We examined 74 patients with angina pectoris and 14 control subjects (age 17 36 years). Angiography revealed coronary artery disease (> or = 30% diameter stenosis) in 44 patients (CAD, age 32 67 years) and smooth coronary arteries in 30 patients (non-CAD, age 22-73 years). Vasodilation following reactive hyperemia and after sublingual nitroglycerin (NTG) was assessed in the brachial artery using B-mode high resolution ultrasound. CAD patients showed markedly impaired FMD compared to the non-CAD group (5.7 +/- 4.8 versus 12.6 +/- 6.7%, P < 0.0001) and to controls (5.7 +/- 4.8 versus 15.7 +/- 3.9%, P < 0.00001). NTG induced similar degrees of vasodilation in the CAD and non-CAD groups but less vasodilation in the CAD patients compared to controls (12.2 +/- 6.3 versus 20.4 +/- 6.9%, P < 0.01). On univariate analysis, impaired FMD in CAD patients and non-CAD patients was related to the extent of coronary disease (1-, 2- or 3-vessel disease; r = -0.67, P < 0.0001), to the maximum percent diameter stenosis in one of the major coronary vessels (r = -0.52, P < 0.0001), brachial artery diameter (r = -0.46, P < 0.0001) and plasma cholesterol level (r = -0.34, P < 0.001). On multiple stepwise regression analysis the extent of coronary disease (r = -0.51, P < 0.0001) and the baseline brachial artery diameter (r = -0.37, P < 0.0001) were independently associated with FMD in CAD and non-CAD patients. The present findings suggest that the impairment of FMD in the brachial artery, a marker of systemic endothelial function, is closely related to the angiographic extent of CAD.

Is oxidative stress causally linked to unstable angina pectoris? A study in 100 CAD patients and matched controls.

OBJECTIVE: Unstable angina pectoris often leads to acute myocardial infarction. Since lipid peroxidation is thought to be causally related to chronic and acute events in atherosclerosis and coronary artery disease, we measured lipid peroxidation products and vitamin E in 100 patients with coronary artery disease and compared them to a matched control group. METHODS: 50 consecutive patients with stable angina pectoris (SAP) and 50 consecutive patients with unstable angina pectoris (UAP) were studied and compared to 100 clinically healthy individuals. In addition to conventional lipid and lipoprotein analysis, malondialdehydes were measured as thiobarbituric acid reactive substances (TBARS). Lipid hydroperoxides were assayed with the colorimetric methylene blue method. alpha-Tocopherol was quantitated by HPLC after extraction of serum with hexane-ethanol. In the patient group conjugated dienes were also measured. RESULTS: As expected, patients had significantly higher cholesterol, triglyceride LDL-C and Lp(a) values and lower HDL-C values than controls. When patients were divided into groups with SAP and UAP respectively, peroxides and TBARS were significantly higher in the latter group as compared to patients with SAP and to controls. Conjugated dienes were also significantly higher in patients with UAP as compared to patients with SAP. Total plasma alpha-tocopherol was comparable in all three groups, whereas the alpha-tocopherol content per LDL particle was lowest in patients with UAP, followed by patients with SAP and then controls. CONCLUSION: It is concluded that lipid peroxidation parameters are increased in patients with UAP and discriminate SAP from UAP patients.