Perioperative Medicine
Divya Gollapudi, MD
A 70 year-old man with history of coronary artery disease with prior stent placement, atrial fibrillation, hypertension, and type 2 diabetes mellitus is admitted with a right-displaced femur fracture after a ground level fall. He denies chest pain, dyspnea, or presyncope. His troponin is negative, and ECG demonstrates atrial fibrillation without ST-T changes. The patient recently underwent a dobutamine stress echocardiogram for evaluation of chronic stable dyspnea on exertion, which demonstrated a small inferolateral wall motion abnormality with stress. You consider if this patient requires a delay in surgery to potentially undergo further evaluation of his coronary artery disease prior to surgery.
What is the role of coronary revascularization in reducing perioperative cardiac complications for patients with stable coronary artery disease?
Coronary revascularization is not recommended for patients with stable coronary artery disease prior to noncardiac surgery exclusively to decrease perioperative cardiac events.
This question was considered in the Coronary Artery Revascularization Prophylaxis (CARP) trial,1 which studied patients with stable coronary artery disease undergoing elective vascular surgery. In CARP, 5859 patients considered at increased risk for
perioperative cardiac complications (as determined by a cardiologist) underwent coronary angiogram. Of these, the 510 with at least 70% stenosis in a coronary vessel were subsequently randomized to either receive or not receive preoperative revascularization with percutaneous coronary intervention or coronary artery bypass grafting prior to surgery (for an expanding abdominal aortic aneurysm or severe symptoms of arterial occlusive disease of the legs). Exclusion criteria included left main disease, left ventricular ejection fraction <20%, or severe aortic stenosis, and prior revascularization without evidence of recurrent ischemia. The primary outcome was long-term mortality (as ascertained via follow-up and longitudinal database), and secondary outcomes included 30-day mortality and myocardial infarction (MI).
perioperative cardiac complications (as determined by a cardiologist) underwent coronary angiogram. Of these, the 510 with at least 70% stenosis in a coronary vessel were subsequently randomized to either receive or not receive preoperative revascularization with percutaneous coronary intervention or coronary artery bypass grafting prior to surgery (for an expanding abdominal aortic aneurysm or severe symptoms of arterial occlusive disease of the legs). Exclusion criteria included left main disease, left ventricular ejection fraction <20%, or severe aortic stenosis, and prior revascularization without evidence of recurrent ischemia. The primary outcome was long-term mortality (as ascertained via follow-up and longitudinal database), and secondary outcomes included 30-day mortality and myocardial infarction (MI).
The median time from randomization to vascular surgery was longer among those receiving preoperative revascularization (54 vs. 18 days among not receiving revascularization, P < .001). After a median of 2.7 years, there was no difference in long-term mortality (22% vs. 23%, RR 0.98, 95% CI 0.70-1.37; P = .92). There was also no difference in 30-day postoperative death or MI. One caveat relates to the fact that the majority of patients in both groups were on medical therapy with beta-blockers, aspirin, and/or statins preoperatively, which could have itself provided perioperative cardiac protection and diminished the differences in long-term mortality between the study groups. A subsequently published analysis2 of the randomized and nonrandomized (excluded) patients of the initial CARP trial cohort revealed that patients with left main coronary disease had improved survival with preoperative coronary revascularization (RR = 0.84 vs. 0.52 among patients without perioperative revascularization; P < .01).
Due to the lack of compelling evidence for coronary vascular intervention preoperatively in this high-risk population, the 2014 ACCAHA guidelines on perioperative cardiac evaluation3 recommend that preoperative coronary revascularization be reserved only for unstable coronary syndromes or circumstances for which practice guidelines for
revascularization already exist, such as left main disease (class I recommendation, level C evidence). This recommendation, although based on data from elective vascular surgery patients, has been broadly applied to noncardiac surgeries.
revascularization already exist, such as left main disease (class I recommendation, level C evidence). This recommendation, although based on data from elective vascular surgery patients, has been broadly applied to noncardiac surgeries.
The patient is scheduled for operative repair of his femur fracture with orthopedic surgery for the next day. His outpatient medication list includes warfarin, amlodipine, aspirin, diltiazem, atorvastatin, and metformin. You notice that his medication list does not include a β-blocker, and the patient confirms that he is not currently taking a β-blocker. Given his upcoming surgery and known coronary artery disease, you consider if a β-blocker should be initiated tonight.
What are the risks and benefits of perioperative β-blocker therapy?
Although perioperative β-blocker therapy can reduce risk of perioperative MI, initiation of beta-blocker therapy within 1 day of surgery or in patients considered low risk for perioperative cardiac complications can increase perioperative stroke and mortality.
This question was addressed in a 2014 systematic review4 that compared perioperative β-blocker therapy with placebo during noncardiac surgery. The review included 17 studies (16 randomized controlled trials, 1 cohort study) and evaluated several cardiac outcomes, including perioperative MI, all-cause mortality, and stroke. The authors reported that among the randomized controlled trials, preoperative initiation of β-blockers decreased nonfatal MI (RR 0.68, 95% CI 0.57-0.81; P < .001) and increased nonfatal stroke (RR 1.79; 95% CI 1.09-2.95; P = .02), hypotension (RR 1.47; 95% CI 1.34-1.60; P < .001), and bradycardia (RR 2.61; 95% CI 2.18-3.12; P < .001). All-cause mortality appeared similar between β-blocker and no-β-blocker therapy (RR 0.96; 95% CI 0.62-1.47; P = .633).
One caveat of this systematic review is that the cumulative data included data from the DECREASE-I5 and DECREASE-IV6 trials, the results of which have been seriously questioned due to concerns of scientific misconduct. DECREASE-I and DECREASE-IV were the only trials to demonstrate a mortality benefit of perioperative β-blocker therapy and the only trials included in the meta-analysis to start β-blockers >1 day prior to noncardiac surgery. After excluding these trials, the remaining studies demonstrated an increase in all-cause mortality with β-blocker therapy (RR 1.30, 95% CI 1.03-1.64; P = .03), suggesting that initiating β-blockers within 1 day of surgery can cause substantial harm.
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