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Results for “Coronary Circulation”

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At least 91 records · Page 5Linked to original sources

PubMed2005

[Changes of neutrophil myeloperoxidase in coronary circulation among patients with acute coronary syndrome].

OBJECTIVE: To investigate the changes of neutrophil myeloperoxidase (MPO) blood concentration gradient between the systemic circulation and the coronary circulation among patients with acute coronary syndrome and its clinical value. METHODS: Fifty patients underwent coronary angiography, which including 10 patients in AMI group, 20 patients in UA group, 10 patients in SA group and 10 subjects served as control. The levels of MPO and hs-CRP were measured in the serum of blood collected from femoral vein, aortic artery root and coronary sinus. RESULTS: Compared with the control, concentrations of LDL in the AMI, UA and SA groups were significantly increased, while the latter three groups did not differ from each other. In the UA patients, the in-gate percentage of MPO decreased in the coronary sinus compared with that in the root of aortic artery (P < 0.01); the in-gate percentage of MPO decreased through coronary circulation more than through systemic circulation (P < 0.001); the average fluorescent intensity of MPO and the concentrations of hs-CRP showed no difference between samples from the coronary sinus and that from the root of aortic artery. In the AMI patients, the average fluorescent intensity of MPO in the coronary sinus was weakened compared with that in the root of aortic artery (P < 0.05); it decreased through coronary circulation more than through systemic circulation (P < 0.001); neither the in-gate percentage of MPO nor the concentrations of hs-CRP showed significant difference between samples from the coronary sinus and that from the root of aortic artery. In the control and SA groups, samples from the femoral vein, the root of aortic artery, and the coronary sinus did not show differences at the serum level of MPO and hs-CRP. In the UA group, the in-gate percentage of MPO correlated positively with the concentration of hs-CRP (r = 0.78, P < 0.01), and with the level of LDL as well (r = 0.52, P < 0.05); In the AMI group, the average fluorescent intensity of MPO correlated negatively with the concentration of hs-CRP (r = -0.80, P < 0.01), and showed no correlation with the level of LDL (r = 0.22, P > 0.05). CONCLUSIONS: MPO is a better marker for inflammation of the local plaques. It may be one of the mechanisms that MPO induces the transforming from LDL to ox-LDL in plaques vulnerability.

Acute Coronary Syndrome↗

PubMed1995

Nitric oxide activity in the human coronary circulation. Impact of risk factors for coronary atherosclerosis.

The bioavailability of nitric oxide (NO) in the human coronary circulation at rest and after acetylcholine (ACH)-induced vasodilation was investigated in 32 patients with angiographically normal coronary arteries. The effects of intracoronary L-NG monomethyl arginine (L-NMMA) were investigated at rest and after ACH, sodium nitroprusside, and adenosine. L-NMMA (64 mumol/min) increased resting coronary vascular resistance by 22% (P < 0.001), reduced distal epicardial coronary artery diameter by 12.6% (P < 0.001), and inhibited ACH-induced coronary epicardial and microvascular vasodilation. These effects were reversed with intracoronary L-arginine. L-NMMA did not inhibit dilation in response to sodium nitroprusside and adenosine. 23 patients were exposed to one or more coronary risk factors. The vasoconstrictor effect of L-NMMA on the epicardial and microvessels was greater in patients free of risk factors: Coronary vascular resistance was 36% higher in patients without risks, compared to 17% higher in patients with risks (P < 0.05). Both epicardial and microvascular dilator effects of ACH were greater in patients without risk factors, and the inhibition of these effects by L-NMMA was also greater in patients without risk factors. Thus: (a) NO contributes importantly to resting epicardial and coronary microvascular tone, (b) coronary vascular dilation in response to ACH is predominantly due to increased production of NO, and (c) despite the absence of angiographic evidence of atherosclerosis, exposure to coronary risk factors is associated with reduced resting and stimulated bioavailability of NO from the human coronary circulation.

Acetylcholine↗

PubMed2005

Effects of interleukin-6 produced in coronary circulation on production of C-reactive protein and coronary microvascular resistance.

We measured plasma levels of interleukin-6 and C-reactive protein at the orifice of the left coronary artery and at the great cardiac vein in patients who had coronary artery disease and those who had angiographically normal coronary arteries (controls). We also measured coronary microvascular resistance in the control group. We found increased levels of interleukin-6 in the coronary circulation of patients who had coronary artery disease compared with controls. This increase correlated with C-reactive protein production in the coronary circulation and coronary microvascular resistance. These findings suggest that a localized cytokine/inflammatory pathway functions in the coronary circulation and that interleukin-6 is involved in modulating coronary vascular tone.

Adult↗

PubMed1996

Endothelin-1 production in coronary circulation in a new canine model of coronary thrombosis.

OBJECTIVE: The purpose of this study was to investigate whether endogenous endothelin-1 (ET-1) production in coronary circulation is associated with acute coronary thrombotic events in vivo. To achieve this goal, we have designed a new experimental canine model of coronary thrombosis. METHODS: In vivo occlusive thrombus was induced by the intracoronary application of radiofrequency energy (660 kHz, 50 W) in closed-chest dogs. Pathological and immunohistochemical examinations of thrombosed coronary artery were performed. In 12 dogs, plasminogen activator was administered intravenously and serial measurements of ET-1, thromboxane B2 (TXB2) and thrombin-antithrombin III complex (TAT) levels in plasma from the coronary sinus, aortic root and inferior vena cava were examined. RESULTS: Occlusive platelet-rich thrombi were attached to the deeply injured intimal surface. TAT and TXB2 increased rapidly soon after the intimal injury and declined after successful thrombolysis. In contrast, ET-1 in the coronary sinus was elevated after reperfusion and was significantly higher than in the aorta. Net ET-1 production in the coronary circulation showed a significant positive correlation with the peak TAT levels (r = 0.69, P < 0.05), but not with TXB2 or total occlusion time as an index of ischemic severity. CONCLUSIONS: Deep intimal injury leads to occlusive coronary thrombus. Thrombus formation and its subsequent lysis is associated with the activation and deactivation, respectively, of the coagulation cascade and platelets. Thrombin generation may stimulate ET-1 production in the coronary endothelium in acute coronary thrombotic events.

Acute Disease↗

PubMed2002

Collateral coronary circulation in the absence of obstructive coronary artery disease.

The presence of collateral coronary circulation almost always accounts for significant obstructive coronary artery disease and its development remains unclear. We present two cases wherein there was a large collateral artery in a patient with angiographically normal coronary arteries. In both cases, the vessel ran in the atrioventricular groove, between the distal right coronary artery and the circumflex artery. We believe that this vessel is of congenital origin and after reviewing the literature we describe the angiographic features that distinguish such a vessel from collaterals that are secondary to coronary stenosis or hypoxia.

Aged↗

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