The effect of the carotid sinus reflex on large coronary artery diameter in anaesthetized dogs

1. The diameter of, and blood flow in, the left circumflex coronary artery was measured in anaesthetized dogs and the carotid sinus reflex was stimulated by bilateral occlusion of the carotid arteries (BCO) for 2 min. 2. The effect of BCO on coronary artery diameter and late diastolic coronary resistance was examined: (a) after bilateral vagotomy; (b) after vagotomy plus antagonism of beta-adrenoceptors with propranolol (1 mg/kg, i.v.); and (c) after vagotomy, antagonism of beta-adrenoceptors and antagonism of alpha-adrenoceptors with phentolamine (0.5 mg/kg, i.v.). 3. After vagotomy BCO increased mean arterial pressure (delta = 72 +/- 7 mmHg), heart rate (16 +/- 3 beats/min), coronary blood flow (37 +/- 11 ml/min) and coronary artery diameter (0.14 +/- 0.04 mm). Late diastolic coronary resistance initially fell (-0.26 +/- 0.13 mmHg min/ml at 30 s) but at the end of the 2 min occlusion it had returned to the baseline level (delta = 0.04 +/- 0.08 mmHg min/ml). 4. In the presence of propranolol BCO increased arterial pressure (28 +/- 12 mmHg), but did not alter heart rate (0.6 +/- 0.4 beats/min) or coronary blood flow (2 +/- 2 ml/min). There was a significant decrease in large artery diameter (-0.24 +/- 0.07 mm) and an increase in late diastolic coronary resistance (0.46 +/- 0.12 mmHg min/ml). A mechanical increase in afterload did not affect large coronary artery diameter or coronary resistance. 5. Antagonism of alpha-adrenoceptors abolished the reflex-induced constriction of the large coronary artery (delta = -0.02 +/- 0.02 mm) and the coronary resistance vessels (delta LDCR = -0.02 +/- 0.03 mmHg min ml).(ABSTRACT TRUNCATED AT 250 WORDS)     

辛伐他汀对高胆固醇血症患者大动脉僵硬度的影响

目的观察辛伐他汀(降血脂药)对未合并冠心病的高胆固醇血症患者动脉僵硬度的影响。方法 51例高胆固醇血症患者应用辛伐他汀20 mg.d-1治疗12周,分别在0,12周测定患者的代谢指标、肱踝脉搏波传导速度(baPWV)。结果辛伐他汀治疗后,患者血浆总胆固醇(TC)、低密度脂蛋白胆固醇(LDL-C)水平均明显降低((P<0.01,P<0.05);与治疗前相比,双侧baPWV水平均显著降低(双侧均P<0.01)。结论辛伐他汀可改善无明确冠心病的高胆固醇血症患者动脉血管硬化程度。     

Effects of adenosine analogs and ouabain on rhythmicity in human coronary artery

The effects of adenosine receptor agonists and ouabain on rhythmicity were studied in coronary arteries obtained from 12 human donors. Ring segments of left anterior descending coronary arteries were suspended in organ baths for measurement of isometric tension. Prostaglandin F2 alpha (PGF2 alpha:10 microM) produced tonic contractions followed by phasic relaxations. The phasic relaxations were completely abolished by either 100 nM ouabain or 50 mM KCl and changed to tonic contraction. The rhythmicity was also inhibited in K+-free medium. The adenosine analogs, 5'-N-ethylcarbo-xamidoadenosine (NECA) and 2-chloroadenosine (CAD) caused a concentration-dependent relaxation of the maximum force, minimum force, and decreased the frequency of rhythmicity. In rings that did not show phasic activity in response to PGF2 alpha, NECA and CAD produced concentration-dependent relaxation of the tonic contraction. Prior treatment with ouabain (100 nM) prevented the relaxing response of these compounds and the development of rhythmicity. Our data show that PGF2 alpha-induced rhythmicity in human coronary arteries could be inhibited by ouabain, alterations in K+ concentrations and by adenosine analogs. The relaxations produced by adenosine analogs could also be inhibited by ouabain.     

Effect of nisoldipine on de-endothelialized large coronary artery in isolated working rabbit hearts

The effect of nisoldipine on coronary vascular resistances, cardiac performance and myocardial oxygen consumption was determined. Rabbit hearts were perfused with a perfluorochemical (FC-43) emulsion. Endothelium was removed from the obtuse marginal and the upper portion of the anterior descending coronary artery. Changes in the internal diameter of these arteries were visualized using injection of Patent Blue Dye (color arteriography). Mean internal diameter of coronary arteries and surface area/unit length were computer calculated. Nisoldipine reduced the constriction of coronary arteries and the decrease on coronary flow induced by histamine. Nisoldipine abolished or reduced the decrease in cardiac output, LVESP, dP/dt and myocardial oxygen consumption. The results demonstrate that in the supported rabbit heart preparation, nisoldipine is an effective dilator of large subepicardial coronary arteries, deprived of endothelial lining, and counteracts constriction of coronary resistance vessels. As a consequence nisoldipine improves performance of the ischemic myocardium.     

Differential vasodilator profile of calcitonin gene-related peptide in porcine large and small diameter coronary artery rings.

The vasodilator profile of calcitonin gene-related peptide (CGRP) was compared in large diameter (3-4 mm outer diameter) and small diameter (less than 1 mm outer diameter) rings from porcine left anterior descending coronary arteries (LAD). CGRP relaxed both sized rings in an endothelium-independent manner but was 10 X more potent in small compared to large diameter rings. Repeated administration of CGRP to small diameter rings did not cause the development of tolerance to its effects, whereas in the large diameter rings marked tolerance developed. Pretreatment with the CGRP peptide fragment, CGRP-(8-37) antagonised the vasodilator effects of CGRP in a concentration-dependent manner, but in large diameter rings, the antagonistic potency of CGRP-(8-37) was 10 X less than that seen in the small diameter rings. This differing vasodilator profile of CGRP in small and large diameter rings of pig LADs may be related to a differential CGRP receptor distribution along their length.     

苯环利定对犬冠状动脉的作用

目的：研究苯环利定（Ｐｈｅ）对犬冠状动脉的作用．方法：利用冠脉条生物检定，电磁流量计记录犬血流量等技术分别观察Ｐｈｅ对犬冠脉螺旋条和麻醉犬冠状动脉血流量的影响，同时观察Ｐｈｅ受体拮抗剂右美沙芬（Ｄｅｘ）的拮抗效应．结果：Ｐｈｅ０１－１００μｍｏｌ·Ｌ－１量效依赖地使冠脉条收缩，Ｄｅｘ非竞争性拮抗Ｐｈｅ效应．Ｐｈｅ１０ｍｇ·ｋｇ－１使麻醉犬冠脉左旋支主干流量增加，从３３４（３５ｍＬ·ｋｇ－１·ｍｉｎ－１增加到５１０（５８ｍＬ·ｋｇ－１·ｍｉｎ－１．左室内压和血压缓慢升高，Ｄｅｘ５ｍｇ·ｋｇ－１对整体Ｐｈｅ作用有拮抗效应．结论：Ｐｈｅ离体与整体的冠脉调节不同，提示Ｐｈｅ中枢和外周调节效应可能不一致，Ｐｈｅ整体调节的复杂性．     

经皮冠状动脉介入术治疗冠状动脉左主干病变疗效观察

目的 观察经皮冠状动脉介入术(PCI)治疗无保护冠状动脉左主干(ULMCA)病变的疗效.方法 对40例ULMCA病变患者采用PCI治疗,随访6～20个月,观察心血管不良事件(MACE)的发生情况.结果 所有患者经PCI治疗即时成功率100.0％,术中无严重并发症.住院期间未发生严重心血管不良事件.术后随访6～20(7±2)个月,术后4周发生急性心肌梗死l例,CAG证实回旋支开口亚急性支架内血栓形成,再次PCI治愈;术后动员28例患者在6～12个月进行CAG复查,其中回旋支开口支架内再狭窄3例,左主干远端-前降支开口再狭窄1例,2例再狭窄患者有心绞痛症状,3例再次行PCI,无需要CABG患者.随访期间无死亡病例.心血管不良事件总的发生率12.5％ (5/40),再狭窄率10.0％(4/40).结论 对经过选择的ULMCA病变进行PCI是安全可行的,有良好的近远期预后.     

Effects of nicorandil on large epicardial coronary artery in conscious dogs

The effect of 2-nicotinamidoethyl nitrate (nicorandil, SG-75, Sigmart) on coronary circulation was studied in conscious dogs, instrumented previously under sterile condition with sonomicrometers for the external coronary diameter measurement, and an electromagnetic flow plobe on the left circumflex coronary artery and a catheter into the thoracic aorta. Intravenous administration of nicorandil in doses of 10, 30, 100 and 300 micrograms/kg increased coronary blood flow dose-relatedly by 13 +/- 2, 24 +/- 3, 144 +/- 18 and 309 +/- 36%, respectively. Nicorandil also increased the diameter of the large epicardial coronary artery by 38 +/- 6, 71 +/- 11, 150 +/- 24 and 173 +/- 26 microns in doses of 10, 30, 100 and 300 micrograms/kg, respectively. To eliminate flow-dependent dilation of the coronary artery, the external diameter of the large epicardial coronary artery was measured during fixing the amount of coronary blood flow constant by a cuff occluder after intravenous administration of nicorandil, however, the degree of coronary diameter increase was not attenuated. Thus, nicorandil dilates both large and small coronary arteries in conscious dogs, the former dilation being independent from changes in coronary blood flow.     

Effect of electrical cardioversion on stented coronary artery

Direct current cardioversion, which produces electrical energy, is highly effective for the termination of cardiac arrhythmia and sometimes is indicated in patients with coronary artery stents due to arrhythmias. Only a few reports have been published describing the potential adverse interactions between foreign bodies and electrical cardioversion. The aim of this animal study was to investigate the acute effect of repeated external defibrillation on coronary artery tissue and adjacent myocardium at the implantation site of coronary stents. Custom-made stainless steel stents were implanted in the coronary arteries of 7 dogs. Rapid ventricular pacing was performed to induce ventricular fibrillation. Defibrillation was achieved [5 J/kg; n=2 and 8 J/kg; n=3]. In 2 animals, coronary stent was implanted but defibrillation was not performed [control group]. The animal’s heart were excised and sent for microscopic examination. The light and electron micrographs of heart muscles showed no histological and ultrastructural changes in defibrillated and control dogs. It is concluded that nickel coating provides good resistance to heat in coronary stents and repeated defibrillation does not cause histopathological changes typical of thermal injury at the implantation site of coronary stent.     

Haemodynamic and coronary actions of ouabain during coronary infusion

Summary The investigations were carried out on 24 mongrel dogs which were anaesthetized with chloralose or sodium pentobarbital. Ouabain was added to the coronary blood (50, 100 and 200 ng/ml coronary blood or 0.7, 1.4 and 2.8×10^–7 M) over periods of 30 or 60 min by intracoronary infusion of the glycoside.Under chloralose anaesthesia, ouabain at concentrations of 100 and 200 ng/ml coronary blood augmented left ventricular dp/dt significantly. No significant changes were observed in coronary resting flow and flow per beat at the same time. Likewise, the maximum reactive hyperaemic blood flow remained constant, indicating the absence of any changes in the tone of the large extramural arteries.Under sodium pentobarbital anaesthesia small decreases in heart rate and increases in left ventricular dp/dt were seen only at the highest ouabain concentration (200 ng/ml). All flow parameters remained unchanged.These experiments provide evidence that concentrations of ouabain which 100- and 200-fold exceed therapeutic maintenance levels and 10- and 20-fold exceed the concentrations that produce constriction of helically cut pig and rabbit coronary arteries in vitro, do not diminish the coronary blood supply of the anaesthetized dog in vivo     

Effects of subcutaneous naratriptan on systemic and pulmonary haemodynamics and coronary artery diameter in humans.

Naratriptan, an effective antimigraine agent, is a selective 5-hydroxytryptamine (5-HT1 )-receptor agonist with a pharmacologic profile similar to that of sumatriptan. The object of this study was to assess the haemodynamic effects of naratriptan in a clinical model previously applied to sumatriptan. Cardiac haemodynamics and coronary artery diameter were measured at baseline and after subcutaneous injections of placebo and naratriptan (1.5 mg, s.c.) in 10 patients undergoing diagnostic cardiac catheterisation. No statistically significant change in mean coronary artery diameter was observed after naratriptan [95% confidence interval (CI), -0.27-0.11 mm: p = 0.37]. Naratriptan injection was associated with statistically significant increases in systolic arterial pressure (95% CI, 7.6-22.0 mm Hg; p = 0.0015), total systemic vascular resistance (95% CI, 74-253 dyn/s/cc; p = 0.003), pulmonary artery systolic pressure (95% CI, 2.0-6.9 mm Hg; p = 0.003), pulmonary vascular resistance (95% CI, 3-34 dyn/s/cc; p = 0.025), and pulmonary artery wedge pressure (95% CI, 1.9-2.4 mm Hg; p = 0.009). Naratriptan, a selective 5-HT1-receptor agonist, caused a vasopressor response in the systemic and pulmonary arterial circulations but was not associated with coronary artery vasoconstriction.     

桡动脉在全动脉化冠状动脉旁路移植术中的应用

目的探讨以桡动脉(radialartery,RA)为主的动脉材料在全动脉化冠状动脉旁路移植术(coronaryarteryby鄄passgrafting,CABG)中的疗效。方法从2000年2月至2005年4月,进行72例全动脉化CABG。每例均采集RA与左内乳动脉(1eftinternalmammaryartery,LIMA)进行CABG。术后密切随访。结果平均每例植入动脉桥3.7±0.91支,其中LI鄄MA72支,RA桥124支。RA单纯端侧吻合45支,序贯吻合79支。Y型桥32支。全组病例仅1例(1.39%)死于室壁瘤切除后发生低心排并急性肾功能衰竭,另有3例术后出现急性肾功能衰竭,2例出现脑血管意外,3~4周后恢复出院。无一例出现术后围手术期心肌缺血。术后平均随访31±1.4月(6～51月),无一例出现心绞痛或心肌缺血。结论以RA为主的全动脉化CABG安全而且疗效好,RA有望在CABG中发挥重要的作用。     

卡托普利对冠状动脉扩张症的治疗

目的评价卡托普利对冠状动脉扩张症的疗效。方法将冠状动脉造影证实为冠状动脉扩张的稳定性心绞痛患者,患者总数40例,随机分为硝酸异山梨酯组和卡托普利组,疗程1年,观察心绞痛发作、平板运动试验、冠状动脉造影等项的影响。结果治疗后卡托普利组总有效率87.5%,硝酸异山梨酯组总有效率17.7%,两组对比有显著差异,P〈0.05。结论卡托普利治疗冠状动脉扩张中明显改善平板运动试验的结果,减少心绞痛的发病,冠脉血流明显改善,所以卡托普利是治疗冠状动脉扩张的有效药物。     

莲心碱对离体猪冠状动脉条收缩性能的影响

目的：观察莲心碱（Lien）拮抗氯化钾（KCl），乙酰胆碱（Ach）和组铵（Hist）所致猪冠状动脉条收缩的作用。方法：离体平滑肌实验方法。结果：不同剂量莲心碱对Kcl,Ach,Hist量效曲线均呈非竞争性拮抗作用，pD'2值分别为4．78，3．85和4．25。莲心碱和维拉帕米（Ver）均能抑制组胺诱导的依内钙收缩，而对氯化钙诱导的依外钙收缩作用较弱。结论：莲心碱具有扩张冠脉的作用，且对冠脉平滑肌细胞依内钙性收缩及依外钙性收缩均有抑制作用。     

二乙酰基莲心碱对猪冠状动脉条的影响

目的:观察二乙酰基莲心碱拮抗氯化钾、乙酰胆碱(Ach)和组胺(His)所致猪冠状动脉条收缩的作用.方法:离体平滑肌实验方法,观察二乙酰基莲心碱对氯化钾,Ach,His所致猪冠状动脉条收缩曲线的影响以及在无钙克氏液中,对His引起猪冠状动脉条第一相收缩和钙引起第二相收缩的影响.结果:不同剂量二乙酰基莲心碱可使氯化钾,Ach,His所致冠脉条收缩量效曲线呈非竞争性拮抗作用,对冠脉条第一相和第二相收缩都有明显的抑制作用结论:二乙酰基莲心碱具有扩张冠脉的作用,此作用与拮抗细胞内钙的释放和抑制外钙内流有关.     

Effect of energostim on myocardial damage during coronary artery occlusion

In contrast to traditional therapy (beta-adrenoblocker and nitrates), energostim improves the systolic and diastolic functions of myocardium during 120-min occlusion of the left descending coronary artery. The energostim-induced improvement in the central hemodynamics is correlated with an adaptive increase in activity of the antioxidant system enzymes in response to the ischemic production of reactive oxygen species, which is evidence of the mobilization of reserves of the enzymatic link in the antioxidant defense system of cardiomyocytes. Analogous pattern is observed in the blood. In the control group of traditional therapy, a decrease in the superoxide dismutase (SOD) activity and the redox potential (NAD/NADH) in myocardium are correlated with a decrease in the maximum rate of pressure increase in the left ventricle (R 6.4, p < 0.01) observed 2 h after the coronary occlusion. In the energostim treated group, there is a correlation between the SOD activity and the content of cytochrome C in mitochondria (R 6.1, p < 0.01): a change in the level of cytochrome C during 2-h acute ischemia is correlated with the decrease in redox potential (NAD/NADH) and in the ratio of glutathione peroxidase to Mn-dependent SOD (r 0.64, p < 0.01). Thus, disturbances in the antioxidant defense system of both myocardium and blood plasma of the patients with acute myocardium infarction are correlated with inability of the energy supply system to utilize oxygen in the process of glycolysis and oxidative phosphorylation in mitochondria. Stable adaptive increase in activity of the antioxidant defense system enzymes and a decrease in the content of cytochrome C in the blood plasma are probably the independent indications of beneficial prognosis and high efficacy of the proposed treatment of the ischemic damage of myocardium.     

Interaction of epoprostenol (PGI2) with vasoconstrictors on diameter of large coronary arteries of the dog

The platelet release products thromboxane A2 (TxA2) and serotonin (5-HT) might contribute to coronary vasoconstriction in humans. We have examined the effects of a TxA2-like analogue (U46619), 5-HT, and epoprostenol (PGI2) on the left anterior descending coronary artery of the dog. Changes in diameter were measured by sonomicrometry during perfusion of the vessel with blood from a support dog, at constant flow and distal resistance. Intra-arterial infusions of 5-HT (0.01-1 mumol/L) and U46619 (0.003-0.1 mumol/L) reduced external diameter of the artery (about 2.0 mm) by 0.12 mm and 0.16 mm, respectively. Intra-arterial PGI2 (0.01-0.1 mumol/L) increased the diameter of the artery (by 0.08 mm) and reduced blood pressure of the support dog (by 23 mm Hg), but did not significantly (p greater than 0.05) reduce the vasoconstrictor effects of either 5-HT (0.3 mumol/L) or U46619 (0.1 mumol/L) infused simultaneously. Indomethacin (5 mg/kg i.v.) doubled the direct dilator effect of PGI2, and increased the sensitivity of the artery to 5-HT (by 11.5-fold) and to U46619 (by 2.8-fold). After indomethacin infusion, intra-arterial PGI2 (0.1 mumol/L) reduced the constriction induced by continuous infusion of 5-HT or U46619. These data suggest that PGI2 may be of limited usefulness in preventing constriction of large coronary vessels because it causes hypotension. However, endogenous PGI2 produced by the coronary vessels or pericardium may modulate the influence of coronary vasoconstrictors, and these tissues are therefore potential targets for PGI2-releasing drugs.     

高血压病程及血脂对冠状动脉造影病变程度的影响

目的探讨高血压病程及血脂与冠状动脉造影病变程度的关系。方法502例住院患者作为研究对象,所有病例均经选择性冠状动脉造影分组,按照有无冠状动脉狭窄及其程度分为：无病变及狭窄性病变、斑块浸润性病变、单支病变、双支病变、三支病变及弥漫病变五组;所有患者入院后测量血压,并对每一个患者进行高血压和糖尿病病史的调查,测定血脂水平;经桡动脉或股动脉途径进行选择性冠状动脉造影。结果随着冠状动脉造影病变程度分级的加重,高血压组患者数逐渐增加,卡方检验示P＆lt;0.01,有显著性统计学意义。在冠状动脉造影病变程度的分级各组中,随着病变程度的加重高血压患者的比例逐渐增多,说明高血压病是冠状动脉病变严重程度的相关因素。高血压病患者的发病病程,随着冠状动脉造影病变程度分级的加重,高血压组患者病程数值逐渐增加,One-WayANOVA过程检验示P＆lt;0.01,有显著性统计学意义。随着冠状动脉狭窄程度的加重,血浆总胆固醇、低密度脂蛋白胆固醇、载脂蛋白B、三酰甘油、脂蛋白（a）水平呈逐渐增高趋势;载脂蛋白A1（ApoAl）、高密度脂蛋白胆固醇有下降的趋势;年龄愈大,冠脉病变的严重程度愈重;体质量、三酰甘油水平在冠心病各组中无明显差别。结论高血压病是冠状动脉病变严重程度的相关因素,高血压病患者病程愈长冠状动脉造影病变程度及范围愈重。     

Active and passive effects of antihypertensive drugs on large artery diameter and elasticity in human essential hypertension.

The effects of antihypertensive drugs on the large arteries consist of two parts: the passive effect due to the change in pressure and the active effect, the drug action per se. This study proposes a method of dissociating the passive effect from the active effect. The diameter of the arterial artery was determined by the pulsed Doppler method and the pulse wave velocity of the brachioradial artery by mecanography. Arterial compliance was calculated by the Bramwell-Hill formula. Active and passive effects were determined by a logarithmic pressure-diameter model. This model was supported by in situ direct measurements of blood pressure and diameter in a segment of the femoral artery in dogs. Six drugs, cadralazine, ketanserin, medroxalol, nitrendipine, captopril, and isosorbide dinitrate, administered orally, were tested in 70 essential hypertensive patients. For all drugs, the pressure reduction induced a passive decrease in arterial diameter (p less than 0.02 to p less than 0.01). Cadralazine actively decreased arterial diameter (p less than 0.01), ketanserin had no active effect on diameter, and medroxalol, nitrendipine, captopril, and isosorbide dinitrate actively increased arterial diameter (p less than 0.05, p less than 0.01, p less than 0.01, and p less than 0.01, respectively). For all drugs, the pressure reduction also induced a passive increase in arterial compliance (p less than 0.05 to p less than 0.01). However, only nitrendipine, captopril, and isosorbide dinitrate actively increased arterial compliance (p less than 0.01, p less than 0.05, and p less than 0.01, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)     

性别对非阻塞性冠状动脉疾病患者冠状动脉微血管功能障碍的影响

目的 分析非阻塞性冠状动脉疾病患者冠状动脉微血管功能障碍(CMD)的影响因素。方法 根据左心室整体冠状动脉血流储备(LV-CFR)界值,经冠状动脉造影证实不存在任何冠状动脉直径狭窄≥50%病变的408例患者分为CMD组(LV-CFR<2,139例)和对照组(LV-CFR≥2,269例)。分析CMD发生以及LV-CFR的影响因素。结果 男性和女性患者CMD发病率相仿(32.5%vs.35.0%)(P>0.05)。CMD组BMI和LDL-C较对照组升高(P<0.05)。Logistic回归分析显示,相对于男性患者,女性CMD发生风险并未增加(P>0.05),而高LDL-C和高BMI是CMD发生的独立危险因素(P<0.05)。多重线性回归分析显示,LV-CFR与LDL-C呈负相关(P<0.05),而与性别没有明显相关性(P>0.05)。结论 性别对CMD的发生和LV-CFR无明显影响。