In Reply:—
The comments by Lena et al. , Kleinman, and Lustik in response to my review article 1are appreciated, as they attest to the importance and clinical relevance of the subject of preoperative cardiology consultation. An acute, evolving myocardial infarction (AMI) that Lena et al. refer to would be considered a major clinical predictor in the American College of Cardiology/American Heart Association guidelines. 2Unless the proposed surgery is an emergency operation for a life-threatening indication, the presence of such a major indicator should lead to a cardiology consultation, as delineated in the review (step 2 in fig. 1 of reference 1). The American College of Cardiology/American Heart Association has published the recommended role of percutaneous transluminal coronary angioplasty (PTCA) and thrombolysis in the setting of an AMI. 3Class I indications for PTCA are as an alternative to thrombolytic therapy in (a) patients with AMI and ST-segment elevation or new or presumed new left bundle branch block who can undergo PTCA of the infarct-related artery within 12 h of symptom onset, or even beyond 12 h with symptom persistence; or (b) patients who are within 36 h of an AMI with ST-segment elevation or new left bundle branch block who develop cardiogenic shock, are younger than 75 yr, and in whom revascularization can be performed within 18 h of onset of shock. I do not disagree with Lena et al. that a patient with an AMI needs immediate attention, in the absence of an overriding consideration of emergency surgery (such as repair of a ruptured abdominal aortic aneurysm), and that PTCA as well as thrombolytic therapy has an important role in the management of such a patient. The relative priority of PTCA and thrombolysis in such a setting is still being worked out. 4
On the other hand, an emergency operation for a life-threatening indication should take priority even over the management of an AMI. “Most true surgical emergencies (e.g. , such as a ruptured abdominal aortic aneurysm, perforated viscus, or major trauma) do not permit more than a cursory cardiac evaluation.”2In such a situation, the anesthesiologist is faced with the challenge of resuscitating the patient and attempting to achieve hemodynamic stability in a way that optimizes coronary perfusion and minimizes myocardial stress. Should the patient survive such an operation, any further necessary coronary intervention may take place postoperatively.
If the proposed surgery is not an emergency but is nevertheless urgent, and if the patient has an AMI, the guideline calls for preoperative management of the major predictor (AMI) by a cardiology consultant. In such a situation, the management strategy chosen for the AMI should consider (1) the increased risk of myocardial infarction and death in patients having noncardiac surgery within 2–4 weeks of coronary stenting 5,6or within 3–4 weeks of coronary artery bypass surgery 7,8; and (2) how long the urgent surgery may be safely delayed. Close collaboration between the anesthesiologist, cardiologist, and surgeon would be essential.
Although Kleinman's candid comments about the value (or lack thereof) of preoperative cardiac consultations are appreciated, I do not believe that the data are available yet to unequivocally state that the consultations are “an exercise in wasted time, money, and effort.” I agree that as anesthesiologists, we should have the tools and data to assess the perioperative risk on the basis of the patient's comorbidities and functional status and the risk of the proposed surgery. In fact, the review 1advocates that we should not seek a consultation to “determine whether cardiology consultation is indicated, and if so, to take the necessary diagnostic and therapeutic measures.”1,,p 755The need for consultation exists (a) for the management of major clinical predictors such as acute coronary syndromes (as Kleinman agrees); and (b) for additional diagnostic workup that is under the purview of the cardiologists, such as stress testing and cardiac catheterization, when such is deemed indicated based on our initial assessment of comorbidities and functional status and the risk of proposed surgery. Note that in the case of the second indication of consultations, the review advocates perioperative β-adrenergic blockade, whenever possible, followed by postoperative cardiac follow-up—as Kleinman agrees. Increasingly, the criteria for ordering additional preoperative cardiac testing are being questioned as being too cost-ineffective and leading to few additional interventions: Morgan et al. , 9for example, found in a retrospective chart review that when dobutamine stress echocardiography is performed in accordance with the American College of Cardiology/American Heart Association guidelines, only 4.7% of the patients had a positive result. Even when they have a positive stress test, they can have a relatively low perioperative complication rates with the use of β-adrenergic blockade, 10,11further questioning the utility of preoperative testing. The day may yet come when the only indication for preoperative cardiac consultations may be for the management of acute coronary syndromes, as Kleinman suggests, but we must gather more prospective data to support such a practice.
In most practices, performance and interpretation of the stress test is currently under the purview of the cardiologists, unlike what Lustik may be implying. Therefore, after we determine a need for such a test, a cardiology consultant should then be involved in the testing. Aronson et al. have demonstrated the feasibility of intraoperative dobutamine echocardiography 12and, as our collective expertise in intraoperative echocardiography increases, performance of preoperative/intraoperative stress echocardiography may possibly come under the purview of our specialty in the future.
The review notes that the studies by O'Keefe et al. 13and by Raymer and Yang 14suggest that severe aortic stenosis may not be a major clinical predictor which necessitates postponement of all nonemergent noncardiac surgery, so the condition may be worked up and treated first. Indeed, a similar conclusion is reached in the review article by Carabello, 15which Lustik quotes. Admittedly, the studies by O'Keefe et al. 13and by Raymer and Yang 14had small n's and were retrospective in nature; however, there are no retrospective or prospective studies with results to the contrary (i.e. , no studies with data indicating that correction of severe aortic stenosis is needed prior to noncardiac surgery). Certainly, severe aortic stenosis is not a condition to be taken lightly, and patients with severe aortic stenosis should be managed intraoperatively with knowledge of the implications of the pathophysiologic changes associated with aortic stenosis. Moreover, there should be an appropriate postoperative follow-up, so that any indicated intervention may be performed, especially if the patient is symptomatic of angina, syncope, and/or dyspnea.
