[Problem of adrenalin and acetylcholine in the coronary vessels].
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Acetylcholine↗
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Electron microscopic autoradiographic localization of carbocromene in the coronary vessel walls and myocardium.
The ultrastructural distribution of 14-C- and the 3-H-carbocromene in monkeys and rats showed a characteristic pattern in the coronary artery wall and the heart muscle. The radioactivity was found to be located on the coronary vessel wall mainly in the tunica media over the smooth muscle cells and in the myocardium over the contractile elements and the mitochondria.
Administration, Oral↗
Remodeling of coronary vessels during aging in purebred beagles.
We compared six young (1 year) and six senescent (11 years) purebred beagles to determine the effects of aging on the coronary microvasculature. The hearts were perfusion-fixed in vitro, and myocardial specimens were subjected to microscopic image analysis. Absolute left ventricular mass increased by 55% with age, while cardiocyte cross-sectional area increased by 10% and 30% in the midmyocardium and endomyocardium, respectively. Although capillary numerical density was lower in the senescent dogs (16% in midmyocardium and 19% in endomyocardium), volume density was similar in the two groups because capillary diameter increased significantly with age in both regions. Capillary length density was reduced by 27% with age in the endomyocardium of the old beagles. Wall/lumen ratios of arterioles of three size classes (less than or equal to 15, 16-25, and 26-50 microns) were found to be nearly identical for the two age groups. Mean arteriolar diameter increased within the smallest size class in both ventricular regions. In contrast, a twofold or greater increase in wall thickness with age occurred in the left anterior descending coronary artery and its first branch, which was mainly due to expansion of the medial interstitium. The connective tissue fraction of the myocardium was significantly higher in the senescent than in the young in the epimyocardium and midmyocardium but not in the endomyocardium. These data provide evidence for three conclusions regarding aging of coronary vessels in beagles. First, a decline in capillary length density is limited to the endomyocardium.(ABSTRACT TRUNCATED AT 250 WORDS)
Aging↗
Inappropriate constriction of small coronary vessels as a possible cause of a positive exercise test early after successful coronary angioplasty.
BACKGROUND: The mechanism responsible for exercise-induced myocardial ischemia early after successful coronary angioplasty (PTCA) is poorly understood. METHODS AND RESULTS: Twelve patients who underwent one-vessel PTCA were studied. Exercise testing was performed before and on day 7 after PTCA, which was repeated after 10 mg sublingual isosorbide dinitrate if the test was positive. Quantitative coronary arteriography was also performed on day 8 after PTCA in the basal state, after intracoronary infusion of 0.9% saline, 1, 5, 10, and 20 micrograms ergonovine, and after 300 micrograms nitroglycerin. All patients had a positive exercise test before PTCA but on day 7, six patients had a positive exercise test (group 1) and six patients (group 2) had a negative exercise test. In group 1, all positive exercise tests on day 7 became negative when repeated after isosorbide dinitrate. Intracoronary ergonovine was associated with a dose-dependent constriction of the PTCA segment, a segment distal to it, and a control segment, with no significant difference in the magnitude of the response between the two groups; maximum constriction for group 1 was 19 +/- 3%, 23 +/- 2%, and 16 +/- 3% (p less than 0.001 versus basal), and in group 2 was 20 +/- 4%, 18 +/- 4%, and 9 +/- 2% (p less than 0.01 versus basal). No angina, ischemic ST segment changes, occlusive, or subocclusive spasm occurred in any patient of either group. CONCLUSIONS: We could find no evidence that exercise-induced myocardial ischemia early after PTCA is related to the presence of fixed angiographic restenosis or to dynamic constriction of any epicardial coronary segment. Therefore, inappropriate small coronary vessel constriction responsive to nitrates should be considered as a possible alternative explanation.
Adult↗
Radionuclide left ventricular volume curves in angiographically proved normal subjects and patients with three-vessel coronary disease.
To determine the diagnostic value of measurements obtained from radionuclide left ventricular volume curves, we compared 12 patients with normal coronary arteries (NL) to 12 patients with three-vessel coronary artery disease (3V CAD). Maximum and mean rates of ejection and filling, times of maximum ejection and filling, durations of systole and diastole, and percentages of ejection and filling during each third were measured at rest and during exercise. The only group differences at rest were a 39 msec (p = 0.002) delay in the time of maximal filling and a 6% (p = 0.04) decrease in first third filling fraction in the 3V CAD patients. The overlap in values for these two parameters, however, did not allow good separation of the patients into NL and 3V CAD groups. During exercise, maximal and mean rates of ejection and filling were significantly lower in the 3V CAD group, but these measurements did not improve on the discriminative value of heart rate and ejection fraction alone. Thus, in both the resting and exercise states, measurements of instantaneous changes in left ventricular volume added little diagnostic information.
Aged↗
[The nerve supply of the coronary vessels of the heart].
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Coronary Vessels↗
Coronary vessels contain enzymes that liberate kinin-like vasodilator substances.
The presence of an acid optimum (pH 6) enzyme capable of generating a spasmogenic, vasodilator polypeptide from human plasma kininogen has been demonstrated in dog coronary arteries, veins and in the wall of the left ventricle. This enzyme also cleaved the tripeptide kallikrein substrate Val-Leu-Arg-pNA. Highest amounts were present in the coronary arteries. Gel filtration (Sephacryl S-300) of coronary artery extracts gave a peak for this acid optimum enzyme of 38, 300 +/- 800 Daltons. Its activity was inhibited by pepstatin but not by aprotinin or soya bean trypsin inhibitor. This enzyme, which is similar to a cathepsin, may play a role in the processing of peptide hormones in the heart and coronary vessels.
Animals↗
A pulsating coronary vessel phantom for two- and three-dimensional intravascular ultrasound studies.
The evaluation of new techniques for 2-D and 3-D intravascular ultrasound (US) imaging (IVUS) often requires the use of a pulsating coronary phantom. This study describes the design, construction and evaluation of a phantom simulating the pulsation of a human coronary artery for IVUS studies. Polyvinyl alcohol (PVA) cryogel was used as a tissue mimic for the coronary vessel, which was incorporated in a custom-built assembly. The phantom was programmed to pulsate under servomotor control, to model the pulsation of a normal coronary artery and 2-D IVUS images were obtained using an IVUS imaging catheter. To evaluate the performance of the phantom, the lumen area variation of the phantom was determined and compared with the programmed pulsation waveforms. Our results showed that phantom pulsation correlated well with the programmed pulsation waveform (r = 0.97). The deviation of the least squares line from the line of identity was calculated to be < 4%.
Coronary Vessels↗
[Age related decrease of high density lipoproteins (HDL) in women after menopause. Quantification of HDL with genetically determined HDL arylesterase in women with healthy coronary vessels and in women with angiographically verified coronary heart disease].
BACKGROUND: The decline in the concentration of high density lipoproteins (HDL) observed in postmenopausal women is thought to contribute to the increasing incidence of coronary artery disease (CAD) after menopause. Human serum arylesterase (EC 3.1.1.2) is exclusively associated with HDL. We therefore investigated possible differences in the decline of HDL-levels and of HDL-subfractions HDL2 and HDL3 between postmenopausal women without and with angiographically documented CAD. PATIENTS AND METHODS: HDL-, HDL2-and-HDL3- concentrations were studied in postmenopausal women with angiographically documented CAD (n = 24; 51 to 72 years mean: 62 years) and compared to HDL-parameters of women without CAD (n = 22; 51 to 81 years, mean: 58 years). Arylesterase activities of HDL2-and HDL3-subfractions and HDL2-cholesterol concentrations were determined after differential precipitation with polyethylene glycol (4.7 mM PEG). Phenotyping of HDL-arylesterase was achieved in CAD patients and in women without CAD after determining hydrolysis of arylesterase substrates paraoxon (PO) and phenylacetate (PA) by calculating paraoxonase/arylesterase activity ratios R (R = [PO]/[PA] x 1000): phenotype A (n = 26) with R < 2.5, phenotype AB (n = 16) with 5.0 < R < 10.7, and phenotype B (n = 4) with R > 13.5. RESULTS: In postmenopausal women with documented CAD, as compared to women without CAD, HDL-cholesterol (55 +/- 3 mg/dl vs. 69 +/- 3 mg/dl HDL2-arylesterase (25 +/- 1 kU/l vs. 33 +/- 2 kU/l), and HDL3-arylesterase (89 +/- 4 kU/l vs. 106 +/- 5 kU/I) were found to be significantly reduced. Analysis of the correlation of lipid parameters and age revealed in CAD patients, but not in postmenopausal women without CAD, a significant increase of total cholesterol (r = 0.42), and significant reductions of both HDL2-arylesterase (r = -0.47) and HDL3-arylesterase (r = 0.74) with increasing age. In contrast, HDL-cholesterol (r = -0.14) and HDL2-cholesterol (r = -0.06) of CAD patients showed only slight and non-significant reductions with age. Since HDL3-arylesterase was found to be age-dependently reduced in women without CAD (r = 0.17), HDL2-arylesterase of postmenopausal women, among all lipid parameters showed the most pronounced differences between women without CAD and CAD patients. The age-dependent decrease of HDL2-arylesterase in postmenopausal women with CAD does not result from an increased frequency of B-allele carriers in the subgroup of CAD patients with an age above the median (64 years). CONCLUSION: Genetically determined serum HDL-arylesterase is well suited to quantify HDL in postmenopausal women without and with CAD. HDL2-arylesterase of postmenopausal women should be evaluated as a screening parameter for both primary and secondary CAD prevention.
Aged↗
[Coronary-bronchial artery fistula and two-vessel coronary disease treated by embolisation of the anastomosis and coronary angioplasty].
Coronary-bronchial artery fistulae are rare and may present with broncho-pulmonary haemorrhage and myocardial ischaemia. The authors report the case of a coronary-bronchial artery fistula associated with bronchiectasis responsible for haemoptysis and discovered at coronary angiography performed during an acute coronary syndrome. Radical treatment by embolisation of this fistula allowed the use of platelet inhibitors and anticoagulants for the coronary angioplasty performed secondarily. This method is an interesting alternative to surgical ligature.
Aged↗
[Retrograde dissection of the common trunk of the left coronary vessel during angioplasty of left anterior descending coronary artery. Apropos of 2 cases].
Acute dissection of the left main coronary artery during coronary angiography or angioplasty is a rare but well known complication; it is attributed to a mechanical trauma caused by the tip of the catheter guide wire. The authors present two cases of dissection at the site of coronary angioplasty with a retrograde extension to the left main stem requiring emergency coronary surgery.
Aged↗
[Hemodynamics in persons without coronary vessel disorders and in patients with stenosing coronary arteriosclerosis].
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Adult↗
[Transluminal angioplasty of the coronary vessels. Preliminary results].
Transluminal coronary angioplasty is a new therapeutic procedure perfected by Gruntzig in 1977 consisting of compressing atheromatous plaques and dilating the arterial lumen with an inflatable balloon-tipped catheter of fixed external diameter. This catheter is introduced into the coronary artery through a preformed catheter guide under radioscopic control. The authors describe their experience of 36 attempts at coronary angioplasty performed over a one year period. The stenosis was catheterised in 30 cases and a good immediate result was obtained in 28 patients (77%). The percentage narrowing was reduced from an average of 79 +/- 8% to 26 +/- 12% (p less than 0.001) and the trans stenotic gradient from 40 +/- 11 mm Hg to 4 +/- 8 mm Hg (p less than 0.001). No serious complications were observed during these procedures. The 8 other patients underwent aorto-coronary bypass surgery as an emergency (2 cases) or otherwise (5 cases). 26 patients with good immediate results are asymptomatic at medium term follow-up, 1 has improved from functional Class IV to II, and I has recurrent Class IV effort angina. 15 patients have been followed up after six months. 14 remain asymptomatic with negative maximal exercise stress testing; 1 has angina. 14/15 stenoses remain dilated, 1 stenosis has progressed (60%). 2 patients developed a new stenosis, 1 of whom underwent another angioplasty procedure (functional Class III). In the 13 remaining patient, clinical improvement was confirmed by exercise stress testing. With strict selection of patients and a prudent operative technique this method seems to be an attractive intermediate therapeutic procedure (over 60% good results at medium term) between medical and surgical management of patients with severe angina and a tight monotruncular stenosis.
Adult↗
Impact of coronary vasa vasorum functional structure on coronary vessel wall perfusion distribution.
Noncoronary vasa vasorum have been described as networks of microvessels in the wall of arteries and veins. However, we have shown, using microcomputerized tomography (micro-CT) imaging methods, that porcine coronary vasa vasorum have a tree-like branching structure similar to the vasculature in general. In this study, we elucidate functional aspects of coronary vasa vasorum perfusion territories. Three pig hearts were injected with radiopaque Microfil via the coronary sinus to fill the left anterior descending coronary arteries (LADs) retrogradely at atmospheric pressure. In three other hearts, LADs were injected antegradely at 100-mmHg pressure via the left main carotid artery. Additionally, six LADs were injected in vivo with a suspension of 100- or 300-microm-diameter microspheres before harvesting of the hearts and injection of the LADs with Microfil. All harvested LADs were scanned intact with micro-CT (20 microm cubic voxels). The spatial density of vasa vasorum (no. of vasa/mm2) was measured in 20-microm-thick cross sections (at 0.4-mm intervals). Retrogradely injected LADs showed high and uniformly distributed vasa vasorum densities in the adventitia (means +/- SE; 5.38 +/- 0.09 vs. 3.58 +/- 0.1 vasa/mm2 in antegradely prepared LADs; P < 0.001). Antegradely prepared LADs showed patchy distributed, low-vasa-vasorum-density territories especially on the myocardial side of the coronary artery wall (epicardial density: 4.29 +/- 0.13 vasa/mm2 vs. myocardial density: 2.80 +/- 0.1 vasa/mm2, P < 0.001). Microembolization reduced vasa vasorum densities significantly (100-mum-diameter microspheres: 3.26 +/- 0.07 vasa/mm2, P < 0.05; 300-microm-diameter microspheres: 2.66 +/- 0.07 vasa/mm2, P < 0.001 vs. antegrade controls) and increased the size of low-vasa-vasorum-density territories. We conclude that coronary vasa vasorum are functional endarteries not connected via a plexus. This characteristic may have a significant impact on the spatial distribution of perfusion and drainage of the coronary vessel wall.
Animals↗
Effect of chronic denervation on pharmacological responsiveness of coronary vessels.
We have hypothesized that the well-established regional heterogeneity of the properties of the vascular smooth muscle results from peculiarities of the microenvironment in every region. In particular, the coronary vasculature has well-established differences between large and small coronary arteries in their responsiveness to alpha and beta agonists, nitroglycerin and adenosine. To test our hypothesis, we altered the micro-environment of coronary vessels by chronic surgical sympathectomy in dogs. Our in vitro studies on vessels from normally innervated hearts confirmed previous studies and showed that in large vessels, alpha and beta epinephrine or norepinephrine responses can be demonstrated; the alpha effect is dominant and epinephrine is a more potent alpha agonist than is norepinephrine. In small vessels only a beta catecholamine effect can be demonstrated. Chronically sympathectomized blood vessels show an alpha norepinephrine effect in small vessels. Denervation caused a reduction in the sensitivity to K+-induced contraction in both large and small vessels. In large vessels the responses to nitroglycerin were not affected by denervation, whereas in small vessels the sensitivity to adenosine was reduced. These results indicate that chronic denervation alters the pharmacological responsiveness of the vasculature to various agonists indicating that vascular smooth muscle possesses the ability to respond to long-term modulatory influences arising in the immediate environment.
Adenosine↗
[Inflammatory etiology of changes of the coronary vessels].
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Coronary Disease↗
Risk stratification of single or double vessel coronary artery disease and impaired left ventricular function using exercise radionuclide angiography.
Patients with 3-vessel coronary artery disease (CAD) and normal left ventricular (LV) function have a worse prognosis if they manifest ischemia during exercise testing. The present study determines if exercise radionuclide angiography can aid in the risk stratification of patients with 1- or 2-vessel CAD and impaired LV function (ejection fraction less than 50%). Sixty-five consecutive patients with these findings were followed for a median duration of 24 months (range 12 to 49). Eleven of the 65 patients (17%) had severely ischemic exercise radionuclide angiograms, defined as: a decrease in ejection fraction with exercise; greater than or equal to 1.0 mm of ST-segment depression; and peak exercise workload less than or equal to 600 kg-m/min. During follow-up 11 patients had initial significant cardiac events: 4 cardiac deaths, 1 cardiac arrest, 4 myocardial infarctions and 2 bypass or angioplasty procedures for unstable angina greater than or equal to 3 months after the exercise study. Four of 11 patients (36%) with severely ischemic exercise radionuclide angiograms had events, compared to 7 of 54 patients (13%) without ischemic radionuclide angiograms. Event-free survival at 18 months was 73% for patients with severe exercise ischemia versus 92% for those without ischemia (p less than 0.05). Univariate analysis showed that severe ischemia on radionuclide angiography was the only variable of several tested that significantly predicted future cardiac events (chi-square = 8.16, p less than 0.005). Among patients with 1- or 2-vessel CAD and impaired resting LV function, severe ischemia on exercise radionuclide angiography identifies a subgroup at high risk for future cardiac events.
Coronary Disease↗
Coronary vessel development requires activation of the TrkB neurotrophin receptor by the Wilms' tumor transcription factor Wt1.
The formation of intramyocardial blood vessels is critical for normal heart development and tissue repair after infarction. We report here expression of the Wilms' tumor gene-1, Wt1, in coronary vessels, which could contribute to the defective cardiac vascularization in Wt1-/- mice. Furthermore, the high-affinity neurotrophin receptor TrkB, which is expressed in the epicardium and subepicardial blood vessels, was nearly absent from Wt1-deficient hearts. Activation of Wt1 in an inducible cell line significantly enhanced TrkB expression. The promoter of NTRK2, the gene encoding TrkB, was stimulated approximately 10-fold by transient cotransfection of a Wt1 expression construct. The critical DNA-binding site for activation of the NTRK2 promoter by Wt1 was delineated by DNase I footprint analysis and electrophoretic mobility shift assay. Transgenic experiments revealed that the identified Wt1 consensus motif in the NTRK2 promoter was necessary to direct expression of a reporter gene to the epicardium and the developing vasculature of embryonic mouse hearts. Finally, mice with a disrupted Ntrk2 gene lacked a significant proportion of their intramyocardial blood vessels. These findings demonstrate that transcriptional activation of the TrkB neurotrophin receptor gene by the Wilms' tumor suppressor Wt1 is a crucial mechanism for normal vascularization of the developing heart.
Animals↗