Perioperative medicine ACP 2013...non invasive cardiac testing

A 73 year old female scheduled for a left femoral to popliteal arterial bypass graft to treat claudication. She has type 2 diabetes which is well controlled on oral agents, mild chronic kidney disease with a baseline creatinine of 1.4 mg/dL, and a history of coronary artery disease. She had an inferior myocardial infarction five years ago. She did not have revascularization and has done well with medical management since that time. Her functional capacity is limited due to the claudication; she is able to walk less than a block, but does not experience angina or dyspnea, only claudication.
On examination, her blood pressure is 140/80. Her pulse is 74 beats per minute and regular. The rest of the physical examination is non-contributory other than diminished pulses in her left lower extremity. Her medications include lisinopril, hydrochlorothiazide, aspirin, atorvastatin, metoprolol, metformin and glipizide.
An electrocardiogram reveals normal sinus rhythm with Q waves in lead 3 and AVF and non-specific ST- T wave abnormalities. A dipyridamole-sestamibi test revealed a fixed inferior wall defect with a small amount of peri-infarct reversibility. The ischemia involves less than 5% of the myocardium. The left ventricular ejection fraction is estimated to be 50%.
What should you recommend?

1. Proceed with surgery, recommending adequate beta blockade and blood pressure control in the perioperative period
   
2. Postpone surgery, refer the patient for dobutamine stress echocardiography
   
3. Postpone the surgery, refer the patient for coronary angiography, and if indicated,
   revascularization
   
4. Cancellation of the surgery because of high surgical risk
   

Correct Answer: A
Discussion:
This patient has a history of an inferior myocardial infarction and her electrocardiogram and myocardial perfusion imaging study confirm this. Most of the defect in the inferior wall is fixed, indicating non- functioning myocardium. However, there is evidence of a small to moderate amount of reversibility around the infarcted area. Because this area of reversibility involves such a small area, it is likely not to increase this patient’s risk of postoperative cardiac outcomes. A meta-analysis of semiquantitative dipyridamole perfusion imaging for cardiac risk assessment prior to non-cardiac vascular surgery found that patients with reversible defects in less than 20% of the myocardial segments did not have an increased risk of perioperative cardiac complications. However, this study did demonstrate an increasing risk of postoperative cardiac complications when greater extents of reversible defects were present. It is therefore most appropriate to proceed with the planned surgical procedure with the appropriate risk reduction strategies of heart rate and blood pressure control. Obtaining another non-invasive stress test is unlikely to change management in this patient, so a dobutamine stress echo would not be indicated. Similarly, coronary angiography is also not indicated. The indications for preoperative coronary angiography are similar to those in the non-operative setting. Recently published appropriate use criteria for diagnostic cardiac catheterization have suggested that cardiac catheterization would be inappropriate in a patient with known previous obstructive coronary disease who is medically managed, asymptomatic and has low-risk non-invasive study findings. Cancellation of the surgery based on high surgical risk in the patient would also be inappropriate. The estimated risk of postoperative myocardial infarction or cardiac death would be in the acceptable range to proceed.

Clinical Pearl:

Patients with low risk findings on non-invasive stress testing do not have an increased risk of postoperative adverse cardiac outcomes and do not need additional testing.
References:

1. Etchells E, Meade M, Tomlinson G and Cook D. Semiquantitative dipyridamole myocardial stress perfusion imaging for cardiac risk assessment before noncardiac vascular surgery: A metaanalysis. J Vasc Surg 2002;36:534-40.
   
2. Fleisher LA, Beckman JA, Brown KA et al. 2009 ACCF/AHA focused update on perioperative beta blockade incorporated into the ACC/AHA 2007 guidelines on perioperative cardiovascular evaluation and care for noncardiac surgery: a report of the American college of cardiology foundation/American heart association task force on practice guidelines. Circulation. 2009;120(21):e169.
   
3. Patel MR, Bailey SR, Bonow RO, et al. ACCF/SCAI/AATS/AHA/ASE/ASNC/HFSA/HRS/SCCM/SCCT/SCMR/STS 2012 appropriate use criteria for diagnostic catheterization. Catheterization and Cardiovascular Interventions. 2012;80:E50–E81.