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Department of Anesthesiology, Rush-Presbyterian-St. Luke’s Medical Center, Chicago, Illinois
Address correspondence and reprint requests to Kenneth J. Tuman, MD, Department of Anesthesiology, Rush-Presbyterian-St. Luke’s Medical Center, 1653 West Congress Pkwy., Chicago, IL 60612.
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The advent of the new millennium, together with the occasion of the World Congress of Anesthesia, provides an excellent opportunity to review and anticipate accomplishments in our specialty. Recognizing that the unique make-up of our Editorial Board—with its focus on subspecialty expertise—gives us the ability to provide this overview from several different perspectives, I asked our Section Editors to review the major past achievements in their respective areas and to attempt a forecast of things to come. The following articles are their responses to that request.— Ronald D. Miller, MD, Editor-in-Chief, Anesthesia & Analgesia
During the last decade, there have been major advances in cardiovascular anesthesiology in many areas, including preoperative cardiovascular risk stratification, identification of management strategies important for cardiovascular outcome, as well as an enhancement of our knowledge and role in perioperative transesophageal echocardiography (TEE).
The evolution of current understanding regarding preoperative cardiovascular risk assessment and stratification began before the last decade, with efforts to define predictors of adverse outcome in specific high-risk populations. These efforts have culminated in the development of cardiovascular risk assessment guidelines, developed by multidisciplinary expert consensus opinion, including expertise from the specialty of anesthesiology (1). Parenthetically, as this knowledge was gained during the last decade, the importance of the anesthesiologist in preoperative evaluation was established, and a reduction in the number of unnecessary cardiology consults demonstrated with the use of effective assessment in a preoperative evaluation clinic (2). The current state of thought regarding perioperative cardiovascular risk assessment is based on the principles of considering both the spectrum of intrinsic patient risk and the risk conferred by the nature and extent of the surgical intervention. Although these principles will likely undergo continual modification as further knowledge is gained, they serve as a useful template for working decisions about perioperative cardiac evaluation (1). Knowledge gained over the last decade now mandates the application of selective, rather than routine, preoperative cardiovascular testing as the approach that most cost effectively identifies those patients requiring aggressive perioperative medical management and most likely to benefit from intensive monitoring during and after noncardiac surgery. It is now known that the nonselective use of noninvasive cardiac evaluation as a preoperative screen is an inefficient use of resources, because at extremes of very low or very high cardiovascular risk, it does not add significant predictive information. What remains controversial and will require further study in the next few years are questions about the type and timing of coronary revascularization as an intervention to reduce cardiovascular morbidity and mortality when high-risk patients require noncardiac surgery.
It is now widely (albeit not universally) accepted that coronary artery revascularization before noncardiac surgery in high-risk patients should be recommended only if there is an anticipated long-term benefit of revascularization. However, there are conflicting data concerning the short-term benefit of coronary artery surgery versus percutaneous transluminal coronary angioplasty (PTCA) to reduce perioperative cardiovascular morbidity and mortality after noncardiac surgery in such patients. Although, PTCA has appeal compared with coronary artery surgery when coronary revascularization is deemed necessary before high risk noncardiac surgery, recent data indicate that the outcome effects may depend on the timing of PTCA before noncardiac surgery as well as the specific type of noncardiac surgery (e.g., abdominal aortic reconstructive surgery versus infrainguinal revascularization) (3,4). It can be reasonably anticipated that these and related issues will be better clarified during the early years of the new millennium.
Cardiovascular research conducted during the last decade has confirmed several fundamental concepts relevant to the perioperative management of patients with ischemic heart disease. For example, it is now widely accepted that postoperative myocardial ischemia is more frequent, typically more severe, and of longer duration, and more likely to be associated with serious adverse cardiac outcomes than preoperative or intraoperative ischemia. Although myocardial ischemia occurs at a finite rate even in the absence of obvious hemodynamic aberrancy, the efficacy of heart rate control to reduce the incidence and severity of myocardial ischemia has also been established in the last several years.
The utility of ß-adrenoreceptor (BAR) blockade to control heart rate and reduce perioperative myocardial ischemia has been demonstrated convincingly in clinical studies in the last decade (5). Findings from studies of BAR blockade in the perioperative setting have been consistent with those beneficial effects observed in nonsurgical patients with ischemic heart disease (6). However, it was not until the very end of the last century that evidence of a definite perioperative outcome benefit (reduction in perioperative myocardial infarction) was demonstrated with perioperative BAR blockade (7). After validation and further elucidation, this dramatic finding, observed in patients with documented high cardiac risk (established with noninvasive testing), and undergoing high-risk vascular surgery, can result in widespread changes in clinical practice. Whether it is appropriate and cost effective to routinely apply this approach to lower risk (as well as "at risk") patients, remains to be answered. Analogous to the recent findings questioning the utility of routine preoperative electrocardiographic testing of elderly patients undergoing low risk surgery (8), the recent findings of outcome benefits of perioperative BAR blockade in high risk patients raises the yet unanswered question of whether routine application of perioperative BAR blockade can eliminate the need for even selective, but nonetheless expensive, noninvasive preoperative cardiac testing. Furthermore, future research will likely answer the questions of when perioperative BAR blockade should begin, what are the proper doses or endpoints of such therapy, and how long postoperatively such therapy should be continued. The development over the last decade of more sensitive methods for clinically detecting myocardial injury (e.g., troponin testing) has resulted in the finding that the greatest risk for perioperative myocardial infarction may occur during the first 24–48 hours postoperatively (9) rather than during the traditionally cited two to four days after surgery. The importance of this recent finding relates to both the appropriate duration of aggressive postoperative medical management as well as intensive monitoring. These aspects of care will likely be better defined in the next few years, as will the role of other interventions such as the use of 
2 agonist drugs, which have shown some potential for improved perioperative hemodynamics and reduced myocardial ischemia in high-risk surgical patients (10). Unfortunately, no study of 2 agonists has yet been adequately powered to demonstrate more than a trend toward reducing the risk of perioperative myocardial infarction.
As the importance of postoperative management of cardiovascular patients was realized in the last decade, there has been a concomitant concern for cost-effective care of the cardiovascular patient. This resulted in the development of clinical pathways focused on rapid recovery and cost savings, prompting the evaluation of the outcome effects of such "fast tracking" approaches to cardiac patients (11). Although the safety of this approach has been validated, it has also been recognized in the last few years that any changes in anesthetic techniques that facilitate rapid recovery are useful only to the extent that they are part of an overall clinical pathway directed at moving the patient to the next phase of recovery in a progressive, nonstagnant fashion. Important differences in overall costs between tracheal extubation at zero to four hours versus four to six hours after cardiac surgery have not been identified, so that as we enter the new millennium, the choice of anesthetic drugs for the cardiovascular patient still has not been shown to be critical to outcome. Maintenance of physiologic homeostasis remains more important than the specific anesthetic technique chosen to accomplish this goal. Although the choice of general anesthesia versus regional anesthesia for intraoperative management of high-risk cardiovascular patients undergoing a variety of surgical procedures has not been shown to have a significant impact on serious cardiovascular outcome, the outcome benefit of postoperative regional analgesia remains controversial, because some data, primarily reported in the 1990s, suggest an outcome benefit of postoperative epidural analgesia in certain high-risk populations, especially those undergoing vascular surgery (12,13). Additional studies are likely to refine our understanding of the role of epidural analgesia in high-risk cardiovascular patients and whether the benefits reported in some studies can be achieved with other methods that are less invasive and labor intensive.
Within the last decade, in addition to "fast tracking," cardiac surgery has changed in other ways that directly involve anesthesiologists and that have required the application of new management and monitoring techniques. Two examples of these changes are the development of "minimally invasive" coronary artery revascularization procedures and the increasing application of valvular repair procedures as an alternative to valve replacement. Although "minimally invasive" techniques for coronary revascularization may reduce the risks of neurologic sequelae by avoiding exposure to cardiopulmonary bypass, these techniques present formidable challenges to the anesthesiologist faced with the demands of pharmacologically slowing the heart to facilitate revascularization without cardioplegic arrest while preserving myocardial and cerebral perfusion. Postoperative pain management is also more complex whenever rib-splitting techniques are involved. Regardless of the more complicated perioperative management required by "minimally invasive" techniques of cardiac surgery, the challenge for the next few years will be to determine, from carefully designed and well conducted studies, whether these techniques are associated with definitive outcome benefit. Similar issues exist for the newer endovascular procedures that are gaining popularity for managing vascular disease of the aorta and peripheral arteries, including the carotid artery.
The increasing frequency of valvular repair for treatment of valvular heart disease has been only one influence motivating the growing use of perioperative TEE by anesthesiologists. With this interest and demand for intraoperative TEE, leaders in the subspecialty of cardiovascular anesthesiology, with the help of the Society of Cardiovascular Anesthesiologists, have been active during the last decade in multidisciplinary efforts to develop guidelines for perioperative TEE as well as to promote the demonstration of skills via a certifying examination (14). TEE is now well established as a useful perioperative tool for assessing cardiac anatomy and function, as well as for evaluating extracardiac structures, primarily the aorta. The challenges for the future will be the development of less costly TEE devices that will facilitate wider application and the incorporation of miniaturized ultrasonographic technology into esophageal probes that could remain in place postoperatively (similar to a nasogastric tube) to facilitate continual cardiac ultrasonographic imaging in the intensive care unit for selected high-risk patients.
In summary, significant advances have been made in the last decade in the perioperative care of surgical patients with cardiovascular disease. The next few years will likely bring further developments and refinements in our approaches to cardiovascular risk stratification, with greater emphasis on better defining management approaches that effectively reduce the risk of adverse cardiovascular outcomes. As newer surgical techniques for management of cardiovascular disease are introduced into broader clinical practice in the next few years, additional clinical challenges will likely be encountered.
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