Percutaneous coronary intervention: historical perspectives, current status, and future directions

In the twenty-six years since Gruntzig introduced a simple balloon angioplasty technique, percutaneous coronary intervention has undergone extraordinary growth and has now surpassed bypass surgery in frequency of performance. Several critical breakthrough technologies account for this remarkable progress: intracoronary stents have increased success rates and reduced restenosis, adjunctive antiplatelet therapy has reduced periprocedural complications, and restenosis after stent placement has been effectively treated with local radiation. Most recently, drug-eluting stents coated with cell-cycle inhibitors have shown great promise for further reducing restenosis, possibly to negligible levels.     

Cardiac resynchronization therapy: current trends and future directions

Despite the clear cut indications for cardiac resynchronization therapy (CRT) laid down by guideline forming bodies, there are numerous unresolved issues. This review article primarily focuses on the current trends in CRT and the challenges encountered in patient selection, procedure related and postimplantation patient management issues. The high rate of non-response to CRT warrants a critical appraisal of the patient selection criteria, with the role of QRS duration and use of imaging to quantify ventricular dyssynchrony being the major points of discussion. Likewise the role of CRT in relatively asymptomatic heart failure patients, those with atrial fibrillation and the benefits of providing an implantable cardioverter defibrillator backup to all CRT devices has yet to be clearly defined. The development of effective and minimally invasive surgical techniques, dependable and reproducible means for optimal pacing site localization and comparative trials on superior mode of lead positioning, pacing sites and optimized CRT programming encompassing diverse patient populations would further advance current standards of CRT. Innovative approaches to resolve these controversies and future goal directed research is needed. Development of novel, comprehensive prediction tools to identify responders to CRT and the possibility of 'leadless' pacing would be interesting futuristic prospects.     

Evolving trends and future directions in echocardiography

The foundation for echocardiography was laid many years ago. From its beginning, the story of echocardiography is replete with translation of creative concepts to reality, that have found wide clinical application. This is eloquently borne out by the events of the last decade, a golden decade that has seen cardiovascular ultrasound blossom as an art and science, and find a clinical niche of its own. Echocardiography combines low-cost with high-technology and easy portability, all attributes that are unmatched by other noninvasive techniques and essential in today's medical world. Newer concepts and evolving advances could only make echocardiography stronger, while we continue to use it to serve the ultimate objective, that is, aiding someone who is ailing. The world of echocardiography has changed and continues to change; the brave new world of echocardiography beckons ...A mind that is stretched to a new idea, never returns to its original dimension. (Oliver Wendell Holmes)     

Percutaneous coronary angioscopy Current status and future directions

Major advances in catheter technology and miniaturization of fiberoptics have allowed clinical percutaneous coronary angioscopy to become a reality. Percutaneous angioscopy yields highly detailed images of intracoronary morphology and pathology. Ongoing clinical trials are investigating the feasibility, safety, and clinical utility of coronary angioscopy, particularly in relation to interventional techniques such as percutaneous coronary angioplasty and the identification of intracoronary thrombi.     

The setting of coronary angioplasty in multivessel disease: current status and future directions

In summary, the use of coronary angioplasty in the setting of multivessel coronary disease has become more common in recent years. Reports indicate that, in carefully selected patients, a high initial success rate and low incidence of complications can be achieved. We have presented a schema for the triage of multivessel disease patients. Examples of each subgroup have been presented to illustrate the basis for this categorization. Our experience using this schema at the San Francisco Heart Institute has been valuable in understanding the initial and long-term results of coronary angioplasty in these patients. It is important that this paradigm (or a similar classification schema) be adopted to assist clinicians in making judgments about alternative approaches in patients with multivessel disease and to provide a common organization for the dissemination of research findings and collaboration among members of the medical community.     

The history of the coronary care unit

The first coronary care units were established in the early 1960s in an attempt to reduce mortality from acute myocardial infarction. Pioneering cardiologists recognized the threat of death due to malignant arrhythmias in the postinfarction setting, and developed techniques for successful external defibrillation. The ability to abort sudden death led to continuous monitoring of the cardiac rhythm and an organized system of cardiopulmonary resuscitation, incorporating external defibrillation with cardiac drugs and specialized equipment. Arrhythmia monitoring and cardiopulmonary resuscitation could be performed by trained nursing staff, which eliminated delays in treatment and significantly reduced mortality. These early triumphs in aborting sudden death led to the development of techniques to treat cardiogenic shock, limit infarct size and initiate prehospital coronary care, all of which laid the foundation for the current era of interventional cardiology.     

Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: New trends and future directions

Fibromyalgia (FM) and chronic fatigue syndrome (CFS) patients often have memory and cognitive complaints. Objective cognitive testing demonstrates long-term and working memory impairments. In addition, CFS patients have slow information-processing, and FM patients have impaired control of attention, perhaps due to chronic pain. Neuroimaging studies demonstrate cerebral abnormalities and a pattern of increased neural recruitment during cognitive tasks. Future work should focus on the specific neurocognitive systems involved in cognitive dysfunction in each syndrome.     

Imaging techniques for coronary artery disease: Current status and future directions

We review the current status and future directions of sestamibi single-photon emission-computed tomography (SPECT), positron emission tomography (PET), magnetic resonance imaging (MRI), and contrast perfusion echocardiography (CPE) for coronary artery disease evaluation. Diagnostic accuracy and adjunctive assessment of ventricular function make sestamibi SPECT the currently favored stress imaging radioisotope technique. Tissue attenuation correction will likely enhance these capabilities of SPECT in the near future. PET potentially offers valuable diagnostic information, as it may be a superior technique where body habitus limits cardiac imaging. We project that it is unlikely to become routinely used for cardiac imaging because of improvements in routine radionuclide imaging and the lack of evidence that the small resolution gain with PET is of importance, given the much larger cost. Cardiac MRI for assessing cardiac function, perfusion, and coronary angiography is an exciting new modality at an early stage of development. The possible comprehensive nature of MRI for coronary artery disease evaluation, potential cost savings related to utilization of a single, noninvasive test, and availability of scanning equipment in current community settings all project an important role for MRI in the future. Contrast perfusion echocardiography is also a relatively new and untested imaging modality which offers great future promise. The recent development of intravenous contrast agents and the current widespread availability of echocardiographic expertise and equipment throughout the country suggest that the speed of development as well as the dispersion of technologic advances will be rapid. We project that these techniques will play important roles in future coronary artery disease testing and will result in improved diagnostic efficacy and possibly cost utility.     

Intravascular ultrasound of the coronary arteries: Current applications and future directions

Although angiography is widely applied in the diagnosis of the coronary artery disease (CAD), studies have questioned the accuracy of radiographic methods. Miniaturized intravascular ultrasound devices offer several potential advantages, including a tomographic orientation and the ability to characterize atherosclerotic plaques. Two dissimilar technical approaches to transducer design have emerged: mechanically rotated devices and multi-element arrays, each yielding small coronary catheters (1.1–1.8 mm in diameter). Initial studies of coronary ultrasound have demonstrated few serious untoward effects. In most normal subjects, the vessel wall is laminar in appearance with an intimal leading edge and subintimal sonolucent layer averaging ≤0.20 mm in thickness. In most CAD patients, the thickness of the leading-edge or sonolucent zone is abnormally increased. Atherosclerotic abnormalities are frequently evident in segments with no angiographic lesion. At sites with a circular lumen shape, minimum diameter by ultrasound and angiography correlate closely, R = 0.93. At sites with an eccentric lumen, significant disagreement between angiography and ultrasound diameter is evident, R = 0.78. Correlation between angiography and ultrasound from percent stenosis is moderate, R = 0.63. Following balloon angioplasty percutaneous transluminal coronary angioplasty (PICA), morphologic findings include complex cracks, splits, and dissections, and minimum lumen diameter by angiography and intravascular ultrasound correlate poorly. Recent advances have improved the utility of coronary ultrasound, including smaller catheters and a device combining a miniature imaging transducer (1.16 mm) with a low profile balloon (0.028–0.033 inch). Important current limitations include inability to visualize the smallest coronaries and tight stensoses. The future of coronary ultrasound is promising, propelled by the unique capability of this modality to image atherosclerotic plaques directly.     

Percutaneous transluminal coronary angioplasty: state of the art and future directions

Summary Current developments in the practice of percutaneous transluminal coronary angioplasty concern increasing the safety of the procedure and reducing the incidence of lesion recurrence. Technical improvements and increased operator experience have greatly expanded the indications for the procedure. With experience, success in dilating proximal discrete lesions is now almost absolute. Old, calcified lesions and chronic total occlusions remain the barriers to total success. Careful case selection and expert anaesthesiology and surgical support are paramount in maintaining low complication rates. The largely unpredictable occurrence of acute vessel reclosure in approximately 2% of patients remains the major problem. This complication is usually the result of uncontrolled intimai dissection. These risks are considerably increased in patients with multivessel and diffuse disease and long lesions. Randomized trials are required to determine if such patients are best managed with bypass graft surgery. Early detection of less advanced coronary disease will ultimately lead to the most effective application of PTCA. Lesion recurrence mav be reduced, in part, by careful attention to achieving an optimal, initial arteriographic and haemodynamic result. Otherwise, the solution to restenosis will depend on the development of pharmacological agents which prevent the rapid regrowth of atheromatous plaque.