Journal of Cardiothoracic and Vascular Anesthesia
Volume 22, Issue 6 , Pages 803-805, December 2008

Coronary Stents and Noncardiac Surgery: Treat the Patient, Not the Stent!

Department of Anesthesiology, University of Florida College of Medicine, Gainesville, FL

Article Outline

 

FOR MORE THAN A thousand years, the oracle of Delphi stood at the foot of mount Parnassus as the ultimate source of knowledge. Those seeking answers to their questions were brought in front of the priestess of the God Apollo (Pythia) who appeared in a trance-like state (presumably from inhalation of ethylene and other vapors venting through the floor).1 Her unintelligible sounds were then “interpreted” by the other temple priests in the form of a coherent statement, and the individuals were sent away. Frequently, such answers were laced with ambiguity, thereby rendering the individuals ultimately responsible for the correct interpretation of the oracular dictum.

Unlike those seeking the oracle's advice, patients demand specific and concise answers from physicians, who frequently must make decisions without the luxury of sufficient or total evidence. In fact, the advocacy of evidence-based medicine covers a broad array of data that at times may be incomplete, outdated, or even of questionable relevance to particular patients.

When evidence is conflicting and a particular problem has significant health care implications, task forces of experts are convened and guidelines are created to decrease uncertainty and to assist individual physicians in decision-making strategies.2, 3, 4 Subsequently, such recommendations undergo revisions and further refinement as new evidence becomes available to replace the old. The magnitude and frequency of change are often related to the prevalence and complexity of the problem and the amount of new information. Such is the case in patients with coronary stents undergoing noncardiac surgery.

The dilemma and approach to these patients have undergone an evolutionary process. Shortly after the introduction of the first-generation bare metal stents (BMSs) into medical practice, it was recognized that such devices carry a significant thrombotic burden, with potentially devastating consequences.5, 6 Therefore, dual antiplatelet therapy was necessary during periprocedural implantation and for a few weeks thereafter. Initial reports of perioperative stent thrombosis shortly after implantation, following abrupt presurgical discontinuation of antiplatelet therapy, led to an initial set of guidelines recommending a waiting period between 2 and 4 weeks before the surgical procedures.6

Longer waiting periods were not advocated because of the risk of restenosis, which was known to occur within a few months in 30% to 40% of patients, thereby leading to ischemic syndromes or to reintervention.6 Because of these concerns, the introduction of the drug-eluting stents (DESs) with sirolimus and paclitaxel was met by an explosive demand for their use, since they proved remarkably effective against the problem of restenosis. This initial enthusiasm was tempered by several reports of increased late thrombosis in response to the discontinuation of dual antiplatelet therapy.7, 8, 9, 10 This problem was noted particularly with off-label use, and it occurs because of delayed endothelial healing of the stent, hypersensitivity to the drug contained within the stent, and other procedural factors not addressed within the initial clinical trials.11, 12, 13 The net outcome has been a partial return to the use of BMSs, although the long-term mortality with either stent is not significantly different.14 Because various definitions of stent thrombosis were used during different DES trials, a task force was convened to standardize the nomenclature.15 Under these new definitions, the occurrence of DES thrombosis, although lower than initially reported, still exceeds that for BMS and with either device it is higher with off-label use. This latter issue is particularly important because off-label use is estimated to be 50% to 60% of all procedures.15, 16

The turmoil over DES and thrombosis mobilized scientific and regulatory agencies as well as the industry to review and update the evidence, and to help educate physicians and patients.17 Yet, it is acknowledged that much uncertainty remains about the long-term safety of these devices. Current guidelines, endorsed by several scientific organizations, address the role of antiplatelet therapy in patients with coronary stents.3, 4, 17 They have extended the period of dual antiplatelet therapy with clopidogrel and aspirin to at least 6 weeks for patients with BMS and 12 months for those with DES, followed by aspirin for life. It is important to emphasize that these recommendations are somewhat arbitrary. They are not based on hard evidence but rather expert opinion, and multiple modifiers have been identified that may extend the so-called “risk” period beyond 12 months.18, 19

The evidence is even scarcer regarding the perioperative approach to these patients. There is no accepted standard or optimal approach regarding management.13, 18 Despite the limitations contained within the current guidelines, they provide a consistent framework to assist the physician in decision making. However, recent publications have cautioned against the uncritical adoption of such recommendations. They report minimal or no stent-related complications in patients undergoing noncardiac surgery, despite temporary discontinuation of antiplatelet therapy during the risk period for late thrombosis (30 days to 1 year after DES placement).20, 21, 22 Thus, clinicians are reminded that guidelines are published to assist sound clinical judgment rather than to substitute for it. To further compound the problem, a lack of physician and patient understanding has significant repercussions on adherence to therapy and may result in adverse perioperative outcomes.21

In this issue of the Journal, Trentman et al23 report the results of their survey of patients with a history of coronary artery stent implantation, addressing their understanding of the importance of the stent and antiplatelet therapy before noncardiac surgery. Their findings reflect the experience of many anesthesiologists confronting these patients. A wide variety of responses were exhibited by health care providers and patients, fostered by ignorance, unawareness, personal beliefs, and excessive concerns for perioperative bleeding. As with a previous survey on beta-blockers by the same authors, they concluded that an important and pressing opportunity for physician and patient education is needed to address this substantial problem.24 The results of Trentman et al are concerning but not surprising. Nonadherence to evidence-based therapy in cardiac patients is well documented in the literature and is associated with bad outcomes.25 Reports suggest that 10% to 20% of patients discontinue long-term therapy with antiplatelet medications within 6 months even when participating in clinical trials in which oversight is substantial.25, 26 Many patients do so either under physician's supervision or on their own. The latter may be caused by prescription errors, lack of understanding, perceived efficacy of treatment and misconceptions of their disease, or adverse effects. Studies of medication compliance have yielded a complex picture of human behavior that incorporates beliefs, attitudes, knowledge, and socioeconomic and demographic factors.27, 28

Similarly, there seems to be wide variability among physicians' (particularly surgeons') understanding about the importance of antiplatelet therapy in patients with cardiovascular disease, including coronary stents. Recent surveys among spinal and orthopedic surgeons in Europe revealed a widespread lack of consensus whether to continue or withhold aspirin or clopidogrel.29, 30 The main deciding factor was personal experience with perioperative bleeding in the presence of antiplatelet therapy, without concerns for a prothrombotic state or reference to published guidelines.

Effective communication between the physician and patient is a key determinant for compliance with treatment. Such communication must occur in a concise, simple, and collegial manner. If patients understand why a drug is given, its correct dose and duration of treatment, and the potential consequences of not taking it as directed, they will be more likely to continue the treatment. This statement presupposes that prescribing physicians have a clear understanding of the benefits and risk of such therapy, an element that appears to be lacking among many surgeons and medical consultants.

As shown by Trentman et al, by the time patients with coronary stents present to a preanesthesia clinic, they have interacted with multiple health care providers. These individuals include the interventional cardiologist, perhaps a regular cardiologist who is responsible for follow-up, a primary care physician or internist, a surgeon, and even a nonphysician midlevel provider; thus, patients are potentially exposed to a multiplicity of opinions that at times may be contradictory. Frequently, the anesthesiologist is placed in the unenviable and precarious position of making last-minute decisions on the day of surgery when patients prematurely have discontinued antiplatelet therapy under physician's orders because of a misguided concern for bleeding. Although reinstitution of antiplatelet therapy, cancellation of cases, or consideration of last-minute alternate strategies can be implemented, they are poor substitutes for the need for increased education and awareness by surgeons and medical consultants.

There is little argument that cardiologists by virtue of their heightened exposure to clinical trials, related journals, and guidelines are constantly reminded of the importance of stenting and monitoring of evidence-based decisions. Because cardiovascular issues are their main focus, they are in a unique position to reinforce guideline recommendations. The results of Trentman et al reflect the experience in many institutions. Thus, cardiologists need to realize that the publication of guidelines and reviews is but one step, and they must take a more active role in educating surgeons and medical consultants within their local institutions. Similarly, surgeons must put aside their narrow concerns about bleeding caused by antiplatelet agents and must seriously consider the potential consequences of their abrupt discontinuation.13, 18, 31 With the current state of knowledge, it is inexcusable for a surgeon to wait until a perioperative catastrophic stent thrombosis occurs before “getting the message.” Automatic decisions to withhold antiplatelet therapy during the presurgical visit must yield to a multidisciplinary approach, including the routine involvement of local cardiologists and anesthesiologists who have evidence-based knowledge of the subject.

This multifaceted approach should be instituted with each patient in order to provide maximum individual benefit. The recognition of additional risk factors in any given patient and frequent examination of newly published evidence will allow physicians to place these patients in the right context and to optimize their perioperative risk/benefit. As clinicians look at the challenges ahead, plagued with many uncertainties and unanswered questions, the author is reminded again of the wisdom of the ancients. Unlike the vague responses given by the Delphic oracle, Hippocrates' teachings unambiguously remind physicians that “each patient is different” and to “treat the patient, not the stent.”32

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References 

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PII: S1053-0770(08)00279-6

doi:10.1053/j.jvca.2008.09.003

Journal of Cardiothoracic and Vascular Anesthesia
Volume 22, Issue 6 , Pages 803-805, December 2008

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