Improvement In Coronary Perfusion Research Articles

Evolution of surgical repair of intraseptal anomalous left coronary artery with myocardial ischaemia.

Anomalous aortic origin of the left coronary artery with intraseptal course is a rare coronary anomaly associated with an increased risk of myocardial ischaemia. The role and techniques for surgical intervention are evolving, with numerous novel surgical techniques for this challenging anatomy reported in the last 5 years. We report our single-centre experience with surgical repair of intraseptal anomalous left coronary artery in the paediatric population, including clinical presentation, evaluation, and short- to mid-term outcomes. All patients with coronary anomalies presenting to our institution undergo standardised clinical evaluation. Five patients aged 4 to 17 years underwent surgical intervention for intraseptal anomalous aortic origin of the left coronary artery between 2012 and 2022. Surgical techniques included coronary artery bypass grafting (n = 1), direct reimplantation with limited supra-arterial myotomy via right ventriculotomy (n = 1), and transconal supra-arterial myotomy with right ventricular outflow tract patch reconstruction (n = 3). All patients had evidence of haemodynamically significant coronary compression, and three had evidence of inducible myocardial ischaemia pre-operatively. There were no deaths or major complications. Median follow-up was 6.1 months (range 3.1-33.4 months). Patients who underwent supra-arterial myotomy (with or without reimplantation) had improved coronary flow and perfusion based on stress imaging and catheterisation data. Surgical approaches to intraseptal anomalous left coronary artery with evidence of myocardial ischaemia continue to evolve, with new techniques demonstrating promising improvement in coronary perfusion. Further studies are warranted to determine long-term outcomes and refine indications for repair.

Coronary Interventions in Pediatric Congenital Heart Disease

Coronary artery lesions represent rare conditions in pediatric congenital heart disease and mainly include coronary artery stenoses (CAS) or coronary artery fistulae (CAF). Due to the small vessel size, pediatric percutaneous coronary interventions (PCI) are demanding and studies concerning long-term results are missing. In this retrospective study, we analyzed indications, procedural details, and post-procedural outcomes in pediatric patients who underwent PCI in our institution. For CAS treatment, procedural success was defined as efficient coronary revascularization with a significant improvement of coronary perfusion. CAF treatment was considered successful, when no residual shunt was detectable. From 1995 to 2020, 32 pediatric patients aged ≤ 18 years received interventional treatment for CAS (n = 24/32) or CAF (n = 8/32). Reasons for CAS were post-surgical (n = 15/24) or post-transplant (n = 9/24). Interventional treatment strategies included coronary angioplasty (20/43), stent placement (10/43), and a combination of both (13/43). In-hospital mortality occurred in 6/24 patients and late mortality in 5/24 patients leading to an overall 5-year survival of 62.5%. Early mortality mainly occurred due to post-ischemic myocardial failure. CAF occlusion was performed using coil embolization (n = 3), placement of vascular plugs (n = 3), a combination of both (n = 1), or a combination of coil embolization and a covered stent (n = 1). Treatment of coronary fistulae was successful in all patients with excellent post-procedural results and no follow-up death. PCI in pediatric patients with congenital heart disease can be performed safely and effectively. However, the overall 5-year survival probability of patients with CAS is reduced due to severe ischemic myocardial damage.

Three-Dimensional Computational Modeling of an Extra-Descending Aortic Assist Device Using Fluid-Structure Interaction

BackgroundThe incidence of heart failure is anticipated to rise by 2030, resulting in more than 8 million adults with this condition in US. Despite the advancement in pharmacological and surgical treatments, some patients progress to severe forms of cardiac dysfunction requiring cardiac transplantation as a last-resort treatment. Cardiac assist devices play an essential role in the recovery of normal cardiac performance through reversible remodeling or in assisting the weak organ to prolong survival rate. However, these devices need to be monitored carefully, as prolonged use may lead to physiological maladaptation and further cardiac complications. The optimization of such devices has done through the development and use of numerical simulations that allow the analysis of in-vivo hemodynamic patterns of blood flow. This study aims to investigate the performance of a model of extra-aortic assist device surrounding the descending aorta through three-dimensional patient-specific modeling. MethodsA three-dimensional model of the aorta was constructed from patient-specific cardiac CT images of a 60-year-old male diagnosed with left ventricular failure at the Tehran Heart Center (THC). Numerical simulation was conducted for two complete cardiac cycles using fluid-structure interaction (FSI) analysis under the assumption that the balloon and the aortic vessel behave as linear elastic materials, and that blood is a Newtonian and incompressible fluid. ResultsThe numerical simulation demonstrated a high correlation between the FSI analysis and clinical data of the patient-specific anatomical and physiological conditions. Blood velocity, pressure, deformation, and strain contours were simulated and analyzed through three-dimensional modeling. Compared to the unassisted aorta, the device provided an increase in blood flow displacement of an additional 15 ml of blood in the descending aorta, brachiocephalic, carotid, and subclavian arteries. The maximum von Mises stress distribution across the aortic vessel was higher than the stress imposed on the system in the unassisted heart, with values of 3.3 MPa and 0.28 MPa, respectively. Numerical investigation of structural responses revealed that no remarkable force was exerted on the aortic valve by the device at the descending aorta. ConclusionWe present the numerical investigation of a counterpulsation device around the descending aorta that has not previously been tested on human or animal models. While this extra-aortic balloon pump (EABP) did not show a significant improvement in coronary perfusion, there is room for improvement in further studies to optimize the geometry of the balloon. Additional investigations are required to determine the efficacy of this device and its safety before in-vivo experimental studies are pursued. This simulation has clinical relevance when choosing an appropriate cardiac assist device to address patient-specific physiological and pathological conditions.

Outcomes with intra-aortic balloon pump in high risk cardiac surgery patients

ABSTRACT Introduction: In high-risk cardiac surgical patients the intra-aortic balloon pump (IABP) is the most frequent used tool for temporary mechanical circulatory support during the perioperative phase. The effects of IABP are an increase in diastolic blood pressure, an improvement in coronary perfusion and a reduction of ventricular afterload, so it increases the stroke volume and cardiac output. Objective: To study the effect of preoperative use of intra-aortic balloon pump (IABP) on the outcome of high-risk patients that were subjected to coronary artery bypass graft (CABG) surgery. Methods: From June 2009 to June 2011. Group of 100 patients considered as high-risk patients were subjected to elective bypass cardiac surgery at our center. Forty patients subjected to preoperative IABP as a prophylactic measure and 60 patients were not subjected to IABP. This is retrospective study of prospectively collected data .The definition of High risk was the presence of two or more known risk factors. The patient’s outcome is compared regarding the predicted mortality of the Euro SCORE. The preoperative effect of IABP on the outcome, mortality and 30 days follow-up was statistically analyzed. Results: Forty patients subjected to preoperative IABP as prophylactic measure due to higher Euro SCORE-predicted mortality than other 60 patients did not subject to IABP(60% vs 40 %, P = ˂0.05). Seventy patients (70%) were male while (30%) were female with a mean age of 58.62 ± 9.65 years. Patients subjected to preoperative IABP had increased a percentage of hospital mortality (P = ˂0.05) but this percentage is relatively lower than predicted by Euro SCORE. Patients subjected to preoperative IABP had lower rate of postoperative complication (acute kidney insult (P = 0.045), cardiac surgical intensive care unit (CSICU) stay (P = 0.032) and decrease the need for postoperative inotrope (P = 0.046)) compared to patients without preoperative IABP use. Other complications postoperative were low and similar in both groups. Conclusions: We conclude that patients have high-risk CABG, the preoperative IABP in this group with higher predicted mortality was associated with a relative reduction than predicted by Euro score. The preoperative IABP in this group has a reliable and acceptable outcome on postoperative complications. Keywords: intra-aortic balloon pump, High Risk, Cardiac Surgery

OUTCOMES WITH INTRA-AORTIC BALLOON PUMP IN HIGH RISK CARDIAC SURGERY PATIENTS

ABSTRACT Introduction: In high-risk cardiac surgical patients the intra-aortic balloon pump (IABP) is the most frequent used tool for temporary mechanical circulatory support during the perioperative phase. The effects of IABP are an increase in diastolic blood pressure, an improvement in coronary perfusion and a reduction of ventricular afterload, so it increases the stroke volume and cardiac output. Objective: To study the effect of preoperative use of intra-aortic balloon pump (IABP) on the outcome of high-risk patients that were subjected to coronary artery bypass graft (CABG) surgery. Methods: From June 2009 to June 2011. Group of 100 patients considered as high-risk patients were subjected to elective bypass cardiac surgery at our center. Forty patients subjected to preoperative IABP as a prophylactic measure and 60 patients were not subjected to IABP. This is retrospective study of prospectively collected data .The definition of High risk was the presence of two or more known risk factors. The patient’s outcome is compared regarding the predicted mortality of the Euro SCORE. The preoperative effect of IABP on the outcome, mortality and 30 days follow-up was statistically analyzed. Results: Forty patients subjected to preoperative IABP as prophylactic measure due to higher Euro SCORE-predicted mortality than other 60 patients did not subject to IABP(60% vs 40 %, P = ˂0.05). Seventy patients (70%) were male while (30%) were female with a mean age of 58.62 ± 9.65 years. Patients subjected to preoperative IABP had increased a percentage of hospital mortality (P = ˂0.05) but this percentage is relatively lower than predicted by Euro SCORE. Patients subjected to preoperative IABP had lower rate of postoperative complication (acute kidney insult (P = 0.045), cardiac surgical intensive care unit (CSICU) stay (P = 0.032) and decrease the need for postoperative inotrope (P = 0.046)) compared to patients without preoperative IABP use. Other complications postoperative were low and similar in both groups. Conclusions: We conclude that patients have high-risk CABG, the preoperative IABP in this group with higher predicted mortality was associated with a relative reduction than predicted by Euro score. The preoperative IABP in this group has a reliable and acceptable outcome on postoperative complications. Keywords: intra-aortic balloon pump, High Risk, Cardiac Surgery

Limitation of Infarct Size and the Open Artery Hypothesis: A Conversation With Eugene Braunwald, MD.

Eugene Braunwald received an MD from the New York University School of Medicine. He completed an internal medicine residency at Johns Hopkins Hospital and cardiology fellowships at Mount Sinai Hospital, Columbia University, and the National Heart Institute. He served as chief of cardiology and subsequently clinical director of the institute. From 1968 to 1972, he was the founding chair of medicine at the University of California, San Diego. From 1972 to 1996, he served as chair of medicine at the Brigham and Women’s Hospital. In 1975, he was elected to the National Academy of Sciences. He is now the Distinguished Hersey Professor of Medicine at Harvard Medical School and a senior investigator of the TIMI Study Group, which he founded in 1984. Dr Braunwald replies: I became aware of the importance of AMI in 1951 during an elective in cardiology during my senior year at the New York University School of Medicine. At the time, AMI was by far the most common cause of death in adults in the United States. Of the patients who survived to be admitted to hospitals (no one knew how many AMI patients failed to reach hospital emergency departments), about one third died before discharge, either suddenly, presumably from an arrhythmia, or secondary to pump failure. Of the patients who were discharged alive, about one quarter died within a year, most frequently as a consequence of heart failure or recurrent MI. Pathologists had taught that AMI was usually associated with coronary thrombosis. Indeed, during my cardiology elective, Herrick’s classic article describing AMI was required reading. Its title, “Clinical Features of Sudden Obstruction of the Coronary Arteries,” showed how these 2 conditions (coronary occlusion and AMI) were intertwined.1 My direct involvement in the care of several patients who did not survive the acute event left …

The ivabradine journey: Table 1

Large body of epidemiological evidence showed strong correlation between heart rate and total or cardiovascular (CV) mortality. These data do not, however, clarify the role of increased heart rate in CV disease, basically because they do not distinguish whether increased heart rate is a risk marker or a risk factor. The distinction is relevant for therapeutic value, since if it is the cause—or one of the causes—of the disease and its progression; its reduction corresponds to a prognostic benefit. Ivabradine, a selective heart rate-lowering agent, provides an opportunity to assess the effects of lowering heart rate without directly altering other aspects of cardiac function. Experimental and clinical data with ivabradine illustrate important therapeutic benefits resulted from this therapy—improvement in coronary perfusion (myocardial perfusion, collateral coronary flow) and cardiac efficiency (improvement in LV function, reversing of remodelling). For this reason, consideration of the ‘Ivabradine journey’ is particularly relevant, not only to establish its therapeutic role in treating different manifestations of the CV continuum but also to establish the role of heart rate in this continuum. Results of SHIFT trial demonstrated that an increased heart rate actively contributes to the outcome as a risk factor, and selective heart rate reduction with ivabradine provides a prognostic benefit. In patients with angina, heart rate is a major determinant of ischaemia and myocardial perfusion time; therefore, heart rate reduction is an integral part of antianginal therapy. In setting of stable coronary artery disease without LVSD, the results of SIGNIfY helped to determine that an elevated heart rate is a risk marker and its reduction does not improve the outcome while improving the symptoms of angina.

Ivabradine in practice

Ivabradine is an innovation in the cardiovascular fraternity with specific heart rate-lowering property, which expresses selective action on pacemaker activity in the sinoatrial node of the heart, resulting into important clinical benefits for improvement in coronary perfusion and pump efficiency. Ivabradine demonstrated substantial antianginal and anti-ischemic efficacy, improvement in exercise capacity and in quality of life in monotherapy or in combination with beta-blockers. The analysis of pooled data from ivabradine angina development programme assessing the antianginal efficacy of ivabradine across several different subgroups provided clinical evidence that ivabradine diminishes angina in all types of patients, whatever their age, sex, severity of angina, and revascularization status, history of previous myocardial infarction, peripheral vascular disease, or diabetes. These clinical benefits make ivabradine an important agent for symptomatic treatment of patients with angina pectoris. The important role of ivabradine in the management of patients with chronic heart failure (HF) is well established and supported by its benefits in prevention of morbidity and mortality demonstrated in SHIFT trial. Efficacy and tolerability of ivabradine in patients with HF, including those with different clinical profiles (elderly; severe disease; low blood pressure; comorbidities, including renal dysfunction, diabetes, chronic obstructive pulmonary disease), make ivabradine particularly pertinent for achievement of all targets in the treatment of HF, including improvement of symptoms and well-being, as well as outcomes. The available wealth of evidence supports the important place of ivabradine as an essential therapeutic modality to enhance the management of patients with angina or chronic HF.

Myxedema coma and cardiac ischemia in relation to thyroid hormone replacement therapy in a 38-year-old Japanese woman

Introduction: Although thyroid hormone deficiency, either clinical or subclinical, is an established risk factor for cardiovascular disease, coronary ischemia in a premenopausal woman in her 30s is relatively rare. Case summary: A 38-year-old woman was referred to our hospital with severe breathlessness and depressed consciousness. Physical examination found facial, abdominal, and pretibial edema; coarse hair, hoarse voice, and dry skin; engorged jugular veins; a distant heart sound; and reduced bilateral entry of air into the chest. Laboratory examinations revealed severe hypothyroidism, hyperlipidemia, and elevated serum levels of carcinoembryonic antigen (CEA) and carbohydrate antigen 125 (CA125). A computed tomography scan showed massive pleural and pericardial effusions. After 3 months of levothyroxine replacement therapy (initial dose: 12.5 μg/d; maintenance dose: 125 μg/d), all abnormal laboratory values associated with hypothyroidism returned to within normal ranges, with the exception of a transient and paradoxical rise in serum thyroid-stimulating hormone levels. However, 3 weeks after the initiation of therapy, the patient reported intermittent chest pains during the course of therapy, and a coronary artery angiogram revealed diffuse stenosis of all 3 branches. The patient underwent coronary artery bypass grafting, with subsequent improvement in coronary perfusion. Discussion: Careful cardiovascular evaluation is recommended before the start of thyroid hormone replacement therapy. In addition, care should be taken in the interpretation of serum biomarkers of malignancy (eg, CEA, CA125) in patients with myxedema, as values may be elevated in a hypothyroid state. Conclusions: Long-standing hypothyroidism may be associated with severe coronary atherosclerosis, even in a relatively young, premenopausal woman. The potential adverse cardiovascular effects of thyroid hormone must be considered during replacement therapy, even in relatively young patients.

Childhood origins of lifestyle-related risk factors for coronary heart disease in adulthood.

Research over the past 40 years clearly points to childhood as a critical period when dietary and lifestyle patterns are initiated which have longterm implications for coronary heart disease risk in adult life. Smoking, high habitual dietary intake of total fat and saturated fat, low exercise level, and excessive alcohol consumption often occur in family aggregates. They are correlated with elevated serum cholesterol, obesity, and hypertension in children, as well as with a predisposition to premature death from coronary heart disease. Intervention studies in children and adolescents show, however, that these lifestyle-risk factors are controllable through education and dietary counselling of the affected individual and their family. Equally important are the emerging data in adults showing that vigorous longterm intervention involving reduction of dietary fat and work-related stress, increased exercise, and elimination of smoking all contribute to a significant improvement in coronary perfusion. Hence, effective dietary and lifestyle management of coronary heart disease can occur at early or later stages of the disease and needs better support from health authorities at the national and international level.

Beta adrenergic blockade: Hemodynamics and myocardial energy metabolism in patients with ischemic heart disease

Systemic and coronary hemodynamics and myocardial intermediary metabolism were studied before and after beta adrenergic blockade with propranolol in 9 patients with ischemic heart disease. A significant reduction was produced in heart rate, left ventricular isometric tension development (dp/dt) and pressure-time per minute, whereas left ventricular end-diastolic pressure rose. Cardiac output and left ventricular mean systolic pressure and mechanical work did not change consistently. Myocardial oxygen consumption was influenced by left ventricular external work and pressure-time per min., the latter having the predominant effect. Myocardial oxygen consumption was not closely related to the consistent reduction of dp/dt, presumably because of wide variations in stroke volume. Coronary blood flow was reduced in 5 of 8 patients, changes in coronary diastolic vascular resistance in most cases favoring the preservation of an autoregulatory mechanism. A constant or reduced coronary arteriovenous oxygen extraction in 6 of 9 patients suggested that changes in perfusion rather than in extraction accommodated the altered myocardial oxygen needs. Propranolol appeared to have no direct action on vasomotor tone but probably reduced extravascular compression resistance. Myocardial efficiency did not change consistently. External efficiency was generally reduced, but internal efficiency rose in 3 patients. When a reduction in efficiency indexes resulted from decreased cardiac work but increased coronary flow and myocardial oxygen consumption, the overstressed myocardium may have benefited. Total myocardial substrate oxygen extraction ratios exceeded 100 per cent under control conditions and after beta blockade; therefore the respective energy contributions of carbohydrates and fatty acids were obscure, and conversion and storage seemed likely. The NAD +/NADH redox potential gradient was consistently changed to a more positive value. Arterial levels of inorganic phosphate and creatine phosphokinase activity rose, and the myocardial balance of creatine phosphokinase became positive after propranolol. The antianginal action of propranolol may be related to the following mechanisms: (1) myocardial work is reduced, thus lessening the disparity between oxygen demand and supply; (2) a relative or absolute improvement in coronary perfusion and myocardial oxygen delivery may result, subject to arteriolosclerotic limitations; (3) changes in myocardial intermediary metabolism and enzyme systems favor lessened cellular hypoxia and enhanced aerobiosis.

Failure of counterpulsation to assist circulation in canine hemorrhagic shock

Summary o 1. A canine irreversible hemorrhagic shock preparation is described. It is produced by lowering the blood pressure to 20 mm. Hg for 40 minutes in the anesthetized, ventilated animal, followed by retransfusion of the shed blood in 15 minutes. 2. Arterio-arterial counterpulsation in animals subjected to hemorrhagic shock caused increased diastolic and decreased systolic pressures. This is known to increase coronary perfusion and decrease the pressure work of the heart. Measurements of flow and cardiac function studied showed no significant differences in the control and counterpulsated groups. 3. It would seem that improvement in coronary perfusion and decreased pressure work of the heart failed to alter the course of the experimental animal with hemorrhagic shock.