ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The advent of cardiopulmonary bypass in the early 1960s allowed surgeons to safely perform complex reconstructions on the heart. Since then, the field of cardiac surgery has progressed to where surgical myocardial revascularization, or coronary artery bypass grafting (CABG), has become the most exhaustively studied operation in the history of surgery, and it has achieved widespread use because its benefits have been so thoroughly documented. The paradoxical fact is that more elderly and debilitated patients benefit the most from cardiac surgery compared with medical therapy, yet they sustain greater risk of morbidity and mortality after cardiac surgery. Most of the recent innovations and refinements in the treatment of coronary artery disease aim toward reduction of trauma without deviating much from the safety and efficacy of the conventional procedures. As a consequence, a greater number of high-risk elderly patients have become candidates for coronary artery bypass grafting (CABG). All of the amendments are caused by changing clinical scenarios brought on by an increased number of aging patients, a greater number of patients requiring re-operations, cost containment, increased discernment about outcome assessment, and also the dominance of coronary bypass being threatened by the success of interventional cardiology.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

Cerebral injury is a major cause of mortality and morbidity of coronary artery bypass grafting. Stroke occurs in 3% of patients and is largely caused by embolization of atheromatous debris during manipulation of the diseased aorta. Cognitive impairment, which is predominantly caused by microembolization of gaseous and particulate matter, mainly generated by cardiotomy suction, is more common. Demonstration of similar cognitive impairment in patients operated on without cardiopulmonary bypass indicates that other pathophysiological mechanisms, such as anaesthesia and hypoperfusion, are also involved. Advances in medical, anesthetic, and surgical management have resulted in a reduction in the incidence of neurological injury in CABG patients over the past decade. On the other hand, an increasingly elderly population with more severe comorbidity, who are more prone to cerebral injury, are increasingly being referred for CABG. Possible mechanisms to reduce overt and subtle cerebral injury are discussed. The use of composite arterial grafts performed on the beating heart may be the most effective way of minimizing the risk of cerebral injury associated with CABG.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The long-term prognosis of patients with ischemic cardiomyopathy is highly variable, depending on the extent of myocardial viability and the success and completeness of the revascularization techniques used. Other important factors include left ventricular function, extent of coronary artery disease (CAD), and patient age. Chronic left ventricular dysfunction in ischemic cardiomyopathy is the result of a mixture of scarred as well as hibernating myocardium. In fact, most patients have both scarring and hibernation in different regions. Transmural biopsies of dysfunctional segments reveals that recovery of function is inversely proportional to the extent of fibrosis and that endocardial fibrosis extending over 30% of the myocardial thickness precludes recovery of function.Naguehet al.[1]evaluated the relation of contractile reserve and thallium uptake in hibernating myocardium to myocardial structure in humans. The authors found that segments with postoperative functional recovery had more wall thickening at low-dose dobutamine echocardiography (DE), higher thallium uptake, and less fibrosis (2.0vs28%) than those segments without recovery. Also, segments with viability on DE had less fibrosis, less vimentin and fibronectin, more glycogen, and higher thallium uptake, than those segments without viability. Importantly, segments viable by single-photon emission computed tomography (SPECT) and DE had significantly less fibrosis (1%) than those viable by only one of the two techniques. In this review, we discuss recent developments in the detection of myocardial viability, including echocardiography, nuclear cardiac imaging, magnetic resonance imaging (MRI), and other techniques.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

While the concept of plaque `vulnerability' implies a propensity towards thrombosis, the term vulnerable was originally intended to provide a morphologic description consistent with plaques that are prone to rupture. It is now known that the etiology of coronary thrombi is diverse and can arise from entities of plaque erosion or calcified nodules. These findings have prompted the search for more definitive terminology to describe precursor lesions associated with rupture, now referred to asthin-cap fibroatheromas. This review focuses on thethin-cap fibroatheroma, as a specific cause of acute coronary syndromes. To put these issues into current perspective, we need to revisit some of the older literature describing plaque morphology in stable and unstable angina, acute myocardial infarction, and sudden coronary death. The morphology, frequency, and precise location of thesethin-cap fibroatheromasare further discussed in detail. Potential mechanisms of fibrous cap thinning are also addressed, in particular emerging data, which suggests the role of cell death “apoptosis” in cap atrophy.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

The use of coronary stents improves the outcomes of percutaneous coronary intervention (PCI). This has led to a rapid increase in their use. Coronary stenting is not without problems and is complicated by both early ischemic events and late restenosis. The combination of anticoagulation with unfractionated heparin (UFH) and the use of antiplatelet agents including aspirin, thienopyridines, and glycoprotein IIb/IIIa inhibitors has led to a major reduction in early ischemic events after stenting. Low molecular weight heparin (LMWH) and direct thrombin inhibitors have a number of theoretical advantages over UFH. Their role as an adjunct to coronary stenting is still under investigation. Trials of systemic pharmacotherapy aimed at reducing in-stent restenosis have been consistently disappointing. Preliminary results of stents coated with agents that inhibit neointimal proliferation are extremely promising. The results of ongoing phase III trials of these coated stents are eagerly awaited.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

A number of mechanical adjuncts to intracoronary stenting are now available to the interventional cardiologist. These devices have assisted in the development of a safer and more effective stenting practice. Intravascular ultrasound-guided stenting has been shown to reduce the rate of subacute thrombosis and subsequent restenosis. It allows a greater appreciation of lesion structure and severity so that an appropriate intervention strategy can be devised. Debulking techniques may allow the optimal deployment of stents so that restenosis is reduced; however, the results of large randomized studies are still awaited. The use of thrombectomy and distal embolization protection devices is emerging as a safer alternate to stenting alone in difficult patient subsets, such as those with thrombus-laden lesions and degenerated vein grafts. Doppler and pressure wires may be useful in determining optimal stent deployment and predict subsequent patient outcomes. An understanding of the indications and limitations of these devices is of increasing importance to the interventional cardiologist as the coming decade threatens to yield an impressive array of high-tech innovations.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

For more than three decades, conventional coronary artery bypass grafting (full sternotomy, cardiopulmonary bypass, and cardioplegic arrest) has been the treatment of choice for patients with multi-vessel coronary artery disease. However, neurologic injury secondary to ascending aortic manipulation and systemic inflammatory reaction related to cardiopulmonary bypass are major causes of morbidity. During the past decade research efforts have been focused on the development of innovative revascularization techniques to minimize these deleterious effects. Minimally invasive direct coronary artery bypass surgery was developed to reduce chest trauma and to accelerate patient recovery. The relatively recent introduction of mechanical stabilizers and positioning devices has allowed for the safe performance of off-pump coronary artery bypass for patients with multi-vessel disease. Robotic technology has offered the possibility of myocardial revascularization through limited access using endoscopic principles. Recently, emphasis has been placed on the development of new sutureless anastomotic devices that may revolutionize the field of myocardial revascularization and allow a broader acceptance of minimally invasive CABG. Despite the increasing availability of new technologies, the validity of these procedures must be evaluated carefully. Prospective randomized studies and longitudinal follow-up will be required.

ISSN:0268-4705    

出版商:OVID    

年代:2001

数据来源: OVID