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My 70 year old female patient with history of hypertension and hyperlipidemia is scheduled to undergo an elective cholecystectomy. She is a nonsmoker and exercises 5 days a week for 30 minutes. Does she need any further noninvasive cardiac testing in addition to an electrocardiogram (ECG)?

Dr. Parimal Maniar: No, according to American College of Cardiology (ACC)/American Heart Association (AHA) guideline, the patient has minor clinical predictors for coronary artery disease (CAD) and good performance status for undergoing an intermediate-risk surgical procedure. Therefore, no further cardiovascular testing is required.

The ACC/AHA guideline recommend preoperative history, physical examination, and ECG assessment that focuses on identifying cardiac diseases that might increase the surgical risk. The guideline advocates an approach that considers major, intermediate, and minor clinical predictors of increased perioperative cardiovascular risk (Table 1).

Perioperative cardiac risk is also affected by variables such as patient’s functional capacity and the type and urgency of surgery a patient requires. If a major risk predictor is present, nonemergency should be delayed for medical management, risk-factor modification and possible invasive cardiac workup. In patient with one or more intermediate risk predictors, functional status should be assessed. Poor functional status is defined as inability to perform activities such as climb a flight of stairs, doubles tennis, and heavy work around the house that require 4 or more metabolic equivalents (METs). Patients with poor functional status should undergo further noninvasive cardiac testing unless low risk surgery such as cataract or breast surgery is planned. Patients with good or excellent functional status require noninvasive cardiac testing only if high risk surgery such as vascular surgery is planned. Finally, patients with minor risk predictors or no risk predictors should have noninvasive cardiac testing if they have poor functional status and are planned to undergo high risk surgery.

In general, the indications for additional cardiac testing and treatment are the same as those in the nonoperative setting, but their timing is dependent on such factors as the urgency of surgery, patient’s clinical risk predictors and specific surgical considerations. Preoperative testing should be limited to circumstances in which the results will affect patient treatment and outcome.

Do all patients undergoing noncardiac surgery benefit from perioperative beta blocker therapy and what should be the duration and dosage of such therapy?

Dr. Parimal Maniar: According to ACC/AHA guidelines, appropriately administered beta blockers reduce perioperative ischemia and may reduce the risk of myocardial infarction and death in high-risk patient. However, in a recent large trial, there was no benefit of perioperative beta-blocker therapy in moderate-risk patients and potential harm detected in the lowest-risk groups. This suggests that careful patient selection remains necessary. The cardioprotective effect of beta-blockers is related to bradycardia and reduced myocardial oxygen demand. The beneficial effect of beta blocker therapy seems to be a drug class effect rather than a particular agent. When possible, beta blockers should be started daysa or weeks before elective surgery, with the dose titrated to achieve a resting heart rate between 50 and 60 beats per minute. Patient should continue taking oral beta-blocker therapy for up to 30 days after the surgery.

My patient with history of CAD and a recent drug eluting stent (DES) placement about 3 months ago needs oral surgery. Patient’s dentist has asked him to discontinue his aspirin and Plavix one week prior to surgery. Is it safe to discontinue his antipletlet therapy for this elective surgery?
Dr. Parimal Maniar: No, drug eluting stents (DES) have dramatically decreased the incidence of coronary artery restenosis from about 20% - 30% with bare metal stents to less than 10% with DES. Thus, in United States today, the majority of patient currently undergoing coronary artery intervention will have a DES implanted. Patients with DES placement require a longer period of antiplatelet therapy than bare-metal stent due to increased risk of stent thrombosis that can result in a myocardial infarction or death. Patients with DES should take both aspirin and a Plavix for periods of up to at least one year after stenting and aspirin indefinitely and patients should not discontinue either aspirin or the Plavix within the first year without consulting their treating cardiologist.
Unfortunately, at present there are no direct data to guide us in care of patients with DES who need noncardiac surgery. If the surgery is elective, than it should be delayed at least 3 months or longer and if possible aspirin should be continued and Plavix should be restarted as soon as possible. If the surgery is urgent, the decision is more complex and it requires a discussion involving the primary care physician, surgeon and the cardiologist.

Primary care physicians are frequently asked to be involved in preoperative evaluation and this should be seen as an opportunity to provide recommendation for long-term care. I would highly suggest that all health care providers caring for these patients review the AHA/ACC guidelines for further details as this article only represents a brief synopsis.



February 2008

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