Relatively few cases of myocardial infarction associated with coronary artery atherosclerosis have been described previously in macaques. In this study the authors report the prevalence and characteristics of coronary artery atherosclerosis and myocardial infarction in 10 rhesus (Macaca mulatta) and two cynomolgus (Macaca fascicularis) macaques that were fed atherogenic diets for 16 months or longer. Our findings show clearly that myocardial infarction occurs in macaques with diet-induced atherosclerosis. The frequency seems to be related to the species, composition of the atherogenic diet, and length of time fed the atherogenic diet. The myocardial lesions are remarkably similar to those described in human beings in terms of location and gross and microscopic characteristics. The characteristics of coronary artery atherosclerosis, including the occurrence of thrombosis, severe stenosis, mineralization, atheronecrosis, and sterol clefts, especially in animals fed the atherogenic diets for longer periods of time, also closely resemble those of the arterial lesions found in human beings. The greatest prevalence of myocardial infarcts was found in rhesus monkeys fed a cholesterol-containing diet with 40% of calories supplied by peanut oil and in cynomolgus macaques from Malaya that were fed the same amount of cholesterol with 40% of calories from lard. Electrocardiographic abnormalities as well as the occurrence of unexpected and relatively sudden death in several of these nonhuman primates are also consistent with signs frequently observed in human beings.
Atherosclerosis impairs endothelium-dependent relaxation of large conduit arteries. Because coronary resistance vessels are spared from the development of overt atherosclerosis, endothelium-dependent responses were examined in these vascular segments. Malaysian cynomolgus monkeys (n = 6) were made atherosclerotic by being fed a 0.7% cholesterol diet for 18 months. Control monkeys (n = 6) were fed a standard diet. Coronary microvessels (122-220 microns) were studied in a pressurized (20 mm Hg), no-flow state using a video-imaging apparatus. Relaxations of microvessels, preconstricted with the thromboxane analogue U46619, were determined in response to acetylcholine, bradykinin, the calcium ionophore A23187, adenosine, and sodium nitroprusside. Microvascular relaxations to bradykinin and A23187 were reduced in atherosclerotic monkeys compared with controls, whereas acetylcholine produced additional contraction in atherosclerotic monkeys. Responses of preconstricted microvessels to adenosine and sodium nitroprusside were identical in atherosclerotic and control animals. Indomethacin did not alter responses in control or atherosclerotic animals. Histologic examination revealed neither intimal thickening nor plaque formation in microvessels of this size class despite marked changes in conduit arteries. Electron microscopy showed minor alterations of endothelial cell morphology in microvessels of atherosclerotic animals. In conclusion, long-term hypercholesterolemia markedly impairs endothelium-dependent vascular relaxation in the coronary microcirculation where overt atherosclerosis does not develop. These changes in endothelial cell function may significantly alter regulation of myocardial perfusion by neurohumoral stimuli.
A 17 year old girl with a congenital right coronary artery to coronary sinus fistula presented with recurrent septic pulmonary embolism secondary to tricuspid valve endocarditis. The diagnosis was made on the basis of echocardiography and cardiac angiography.
This is a review of the first 100 coronary stents implanted for the indications of PTCA restenosis, acute or threatened closure and De Novo lesions. The success rates were high and complications rates were low. Subacute stent thrombosis rates were low and stenting for De Novo lesions in > 3.0 mm arteries provide the best short and long term results. Six months restenosis rate was low. Stent assisted high pressure balloon angioplasty is an important advance.
The present study was conducted to examine the effect of bradykinin and bradykinin 2 receptor antagonist on survival time in rats with coronary artery ligation for 15 min and continuously. We also evaluated the heart rate and blood pressure responses in the presence and absence of bradykinin and its antagonist. Bradykinin treatment (4 microg and 8 microg/kg IV) significantly (p < 0.05) increased the survival time of rats compared with saline-treated rats with coronary artery ligation for 15 min and continuously. The heart rate and blood pressure responses were significantly (p < 0.001) altered in the presence of coronary artery ligation. Bradykinin antagonist treatment (4 microg/kg IV) abolished the effect of bradykinin and thus reduced the survival time of rats with coronary artery ligation. The mean value of survival time between saline-treated and bradykinin antagonist- plus bradykinin-treated rats did not differ significantly (p > 0.05).
Coronary sinus perforation is a relatively uncommon but much feared complication that may occur during the placement of left ventricular pacing lead. Coronary sinus perforation, especially in the presence of an obstructive flap, usually indicates the need to abandon the implantation attempt, as there are difficulties in crossing the obstructive flap as well as uncertainty of whether the lead is in the true lumen or into the pericardial space. We describe our experience in successfully placing the left ventricular lead safely despite the problems arising from these circumstances.
Background: Kawasaki Disease (KD) and acute rheumatic fever are the two leading causes of acquired heart disease in children in the developing countries. Objectives: To determine the epidemiology of KD and its short-term outcome in Malaysian children. Materials & Methods: A retrospective study of patients with a diagnosis of KD at the Kuala Lumpur Hospital from January 1999 to December 2003. Results: 84 patients with KD were seen over the 5 year period. Of these, 52 (61.90%) were male and 32 (38.10%) female. Malays comprised 51 (60.71%), Chinese 30 (35.71%) and Indian 3 (3.57%). Their ages ranged from 2 months to 11 years 1 month old. There were 25 (29.76%) patients less than one year old, 50 (59.52%) aged 1-4 years, 4 (4.76%) aged 5-7 years and 5 (5.95%) were more than 7 years old. Echocardiographic examination during the acute phase showed that 24 patients (28.57%) had coronary artery dilatation; 23 had mild dilatation and one had giant aneurysm involving both coronary arteries. Echocardiographic examination at 8 weeks showed that 5 (21.74%) of the 23 patients with mildly dilated coronary arteries had resolved; the bilateral giant coronary aneurysms remained the same. There was no death due to KD over the 5 year period. Conclusion: KD occurred most commonly in children aged 1-4 years old with a peak at 17 months. There was male preponderance with a male to female ratio of 1.6:1. Despite immunoglobulin therapy, 29% of patients had coronary artery involvementduring the acute phase; 22% of those with mild coronary artery dilatation resolved at 8 weeks after disease onset.
This is a case report of 16-year-old adolescent school boy who died due to unusual calcification of coronary arteries. He died while cycling with his friends. While cycling fast he fell. He was brought dead to hospital. At times unsuspected cardiac lesions cause sudden death during extraneous physical activities in healthy persons. Sudden death in adolescents is not very common. It is an unusual case as apparently healthy adolescent boy actively participating in sports had stony hard coronary arteries. The coronaries showed advanced calcification and early bone formation. The myocardial septum had extensive fibrosis. The pathogenesis and other possible similar conditions are also discussed in the report.
Coronary artery stent dislodgement during angioplasty is a rare complication. Stent dislodgement was more frequent in the past when stents were manually crimped onto the balloon. Newer and improved balloon-mounted stents with better radio-opacity have reduced the incidence of stent dislodgement but do not completely eliminate it. We report a case of balloon-mounted stent dislodgement in the proximal left anterior descending (LAD) coronary artery prior to deployment. This patient however was successfully treated with re-wiring of the artery with two parallel wires and the stent's reposition prior to deployment with the help of a small balloon.
While selective non-steroidal anti-inflammatory drugs, namely cyclo-oxygenase-2 (COX 2) inhibitors, are known to be associated with acute myocardial infarction, little is known about the cardiovascular safety of the non-selective non-steroidal anti-inflammatory drugs. We report the case of a 44-year-old man who developed anaphylactic reaction and acute inferior myocardial infarction following ingestion of a non-selective anti-inflammatory drug, diclofenac sodium. Coronary angiography revealed a large thrombus in the right coronary artery which was partially removed by intracoronary catheter aspiration. Complete resolution of the remaining thrombus was achieved after treatment with an oral anticoagulant.
We report a-56-year old army pensioner who presented initially to a peripheral hospital with acute ST-elevation inferior myocardial infarction thrombolysed with streptokinase. He was subsequently referred to the National Heart Institute (Institut Jantung Negara, Malaysia) for coronary revascularization. Coronary angiogram revealed an ectatic right coronary artery with discrete lesions at the proximal and distal segments stented with bare metal stents (BMS). Post dilatation shots revealed a wire-induced, distal dissection at the posterior left ventricular artery remedied by balloon angioplasty but resulting in balloon-induced crumpling of the distal BMS. We discuss the importance of sequential, distal-to-proximal coronary intervention, stent crumpling and remedial strategies.
Coronary Artery Disease (CAD) is responsible for most of the deaths in patients with cardiovascular diseases. Diagnostic coronary angiography analysis offers an anatomical knowledge of the severity of the stenosis. The functional or physiological significance is more valuable than the anatomical significance of CAD. Clinicians assess the functional severity of the stenosis by resorting to an invasive measurement of the pressure drop and flow. Hemodynamic parameters, such as pressure wire assessment fractional flow reserve (FFR) or Doppler wire assessment coronary flow reserve (CFR) are well-proven techniques to evaluate the physiological significance of the coronary artery stenosis in the cardiac catheterization laboratory. Between the two techniques mentioned above, the FFR is seen as a very useful index. The presence of guide wire reduces the coronary flow which causes the underestimation of pressure drop across the stenosis which leads to dilemma for the clinicians in the assessment of moderate stenosis. In such condition, the fundamental fluid mechanics is useful in the development of new functional severity parameters such as pressure drop coefficient and lesion flow coefficient. Since the flow takes place in a narrowed artery, the blood behaves as a non-Newtonian fluid. Computational fluid dynamics (CFD) allows a complete coronary flow simulation to study the relationship between the pressure and flow. This paper aims at explaining (i) diagnostic modalities for the evaluation of the CAD and valuable insights regarding FFR in the evaluation of the functional severity of the CAD (ii) the role of fluid dynamics in measuring the severity of CAD.
Biodegradable stents are considered to be a recent innovation, and their feasibility and applicability have been proven in recent years. Research in this area has focused on materials development and biological studies, rather than on how to transform the developed biodegradable materials into the stent itself. Currently available stent technology, the laser cutting-based process, might be adapted to fabricate biodegradable stents. In this work, the fabrication, characterization and testing of biodegradable Fe-Mn stents are described. A standard process for fabricating and testing stainless steel 316L stents was referred to. The influence of process parameters on the physical, metallurgical and mechanical properties of the stents, and the quality of the produced stents, were investigated. It was found that some steps of the standard process such as laser cutting can be directly applied, but changes to parameters are needed for annealing, and alternatives are needed to replace electropolishing.
We report a 13-year-old girl diagnosed with systemic lupus erythematosus (SLE) who presented with left-sided chest pain, with ECG changes and elevation troponins that were suggestive of an acute inferior wall myocardial infarction (MI). Her multi-slice computed tomography coronary angiogram and standard angiogram were normal. The cardiac magnetic resonance imaging revealed an area of infarcted myocardium that was in the right coronary artery territory. We believe her MI was most likely secondary to coronary vasospasm. MI is rare and coronary vasospasm is an uncommon cause of MI in children and adolescents with SLE.
Identifying susceptible genes associated with the pathogenesis of atherosclerosis (ATH) may contribute toward better management of this condition. This preliminary study was aimed at assessing the expression levels of 11 candidate genes, namely tumor protein (TP53), transforming growth factor, beta receptor II (TGFBR2), cysthathionenine-beta-synthase (CBS), insulin receptor substrate 1 (IRS1), lipoprotein lipase (LPL), methylenetetrahydrofolate reductase (MTHFR), thrombomodulin (THBD), lecithin-cholesterol acyltransferase (LCAT), matrix metallopeptidase 9 (MMP9), low density lipoprotein receptor (LDLR), and arachidonate 5-lipoxygenase-activating protein (ALOX5AP) genes associated with ATH. Twelve human coronary artery tissues (HCATs) were obtained from deceased subjects who underwent post-mortem procedures. Six atherosclerotic coronary artery tissue (ACAT) samples representing the cases and non-atherosclerotic coronary artery tissue (NCAT) samples as controls were gathered based on predetermined inclusion and exclusion criteria. Gene expression levels were assessed using the GenomeLab Genetic Analysis System (GeXP). The results showed that LDLR, TP53, and MMP9 expression levels were significantly increased in ACAT compared to NCAT samples (p < 0.05). Thus, LDLR, TP53, and MMP9 genes may play important roles in the development of ATH in a Malaysian study population.
Functional assessment of a coronary artery stenosis severity is generally assessed by fractional flow reserve (FFR), which is calculated from pressure measurements across the stenosis. The purpose of this study is to investigate the effect of porous media of the stenosed arterial wall on this diagnostic parameter. To understand the role of porous media on the diagnostic parameter FFR, a 3D computational simulations of the blood flow in rigid and porous stenotic artery wall models are carried out under steady state and transient conditions for three different percentage area stenoses (AS) corresponding to 70% (moderate), 80% (intermediate), and 90% (severe). Blood was modeled as a non Newtonian fluid. The variations of pressure drop across the stenosis and diagnostic parameter were studied in both models. The FFR decreased in proportion to the increase in the severity of the stenosis. The relationship between the percentage AS and the FFR was non linear and inversely related in both the models. The cut-off value of 0.75 for FFR was observed at 81.89% AS for the rigid artery model whereas 83.61% AS for the porous artery wall model. This study demonstrates that the porous media consideration on the stenotic arterial wall plays a substantial role in defining the cut-off value of FFR. We conclude that the effect of porous media on FFR, could lead to misinterpretation of the functional severity of the stenosis in the region of 81.89 %-83.61% AS.