Preoperative risk assessment using coronary CTA in a patient with aortic valve endocarditis
Manju Goyal, MD, Todd C. Villines, MD, Lance E. Sullenberger, MD, Eddie Hulten, MD, MPH, and Irwin M. Feuerstein, MD
Background
Conventional coronary angiography (CCA) prior to aortic valve surgery has been traditionally recommended in the majority of patients so that significant obstructive coronary artery disease (CAD) can be addressed at the time of surgery. However, catheter-based CCA is associated with a small risk of serious complications directly related to its invasive nature. Based on the specificity and sensitivity of modern 64-slice cardiac computed tomography angiography (CTA) for detecting obstructive CAD, 1 many advocate and some have reported the successful use ofcoronary CTA to exclude CAD in low-to-intermediate cardiovascular risk patients prior to valve surgery.2 Current appropriateness criteria developed jointly by the American College of Cardiology and American College of Radiology do not address the use of coronary CTA in patients prior to undergoing cardiac surgery.3
Case History
The patient reported here is a 54-year-old man with a history of hypertension, hyperlipidemia, and recurrent urinary tract infections of hisileal neobladder, which was created following resection of transitional cell carcinoma. He was admitted for new-onset New York Heart Association class III heart failure, subjective fevers, and a new diastolic murmur. Transesophageal echocardiogram (TEE) showed a bicuspid aortic valve with 2-cm vegetation (Figure 1), severe aortic insufficiency, and a possible perivalvular abscess. A comparison transthoracic echocardiogram performed 6 months earlier showed no vegetation or aortic insufficiency. Blood and urine cultures grew Enterococcus faecalis, and hewas treated with intravenous penicillin and gentamicin based on organism sensitivities.
Because of the presence of heart failure secondary to severe aortic insufficiency and possible perivalvular abscess, the patient was referredfor aortic valve replacement, in accordance with current guidelines.4 There was concern that invasive CCA could lead to septic emboli causedby dislodgement of the highly mobile aortic vegetation located near his coronary artery ostia. Given his low-to-intermediate risk for obstructiveCAD, we elected to use coronary CTA for preoperative assessment. Imaging was performed using a 64-row multidetector CT scanner(LightSpeed VCT, GE Healthcare, Waukesha, WI) with the following parameters: 120 kVP, gantry rotation time 0.35 seconds, 0.625-mm detector thickness, 700 mA, cardiac helical application, and retrospective gating. Following a timing bolus, contrast (Isovue 370, Bracco Diagnostics,Princeton, NJ) was infused at a rate of 5 mL/sec for a total 85 mL, followed by 20 mL of saline. The cardiac CTA showed a heavily calcifiedbicuspid aortic valve (aortic valve Agaston calcium score of 2973) with a long vegetation ((Figure 2 and Figure 3). The left ventricle was mildly dilated with normal systolic function. Coronary CTA images showed only a nonobstructive mixed (calcified and noncalcified) lesion in the mid leftanterior descending artery (Figure 4). There was no significant CAD seen in the left main, left circumflex, or right coronary arteries (Figure 5 and Figure 6). Additionally, no perivalvular abscess was seen, and the aorta was normal. The possible perivalvular abscess seen on theTEE was actually a dilated left atrial appendage.
The patient underwent uncomplicated aortic valve replacement with a 2-mm SJM Regent valve (St. Jude Medical, Inc., St. Paul, MN). Culture of his aortic valve was positive for E faecalis, and no evidence of perivalvular abscess was appreciated intraoperatively. The patient has since recovered well.
Conclusion
Based on this case, our experience in similar patients, and current literature, we believe that modern 64-slice CTA is an accurate method toassess for obstructive CAD prior to valve surgery in patients who are at low-to-intermediate risk for CAD or in patients who are deemed highrisk for cardiac catheterization, such as those with aortic valve endocarditis. Furthermore, cardiac CTA may help to better define possible structural abnormalities seen on other noninvasive imaging modalities.
REFERENCES
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- Meijboom WB, Mollet NR, Van Mieghem CA, et al. Pre-operative computed tomography coronary angiography to detect significant coronary artery disease in patients referred for cardiac valve surgery. J Am Coll Cardiol. 2006;48:1658-1665.
- Hendel RC, Patel MR, Kramer CM, et al. ACCF/ACR/SCCT/ SCMR/ASNC/NASCI/SCAI/SIR 2006 appropriateness criteria for cardiaccomputed tomography and cardiac magnetic resonance imaging: A report of the American College of Cardiology Foundation Quality Strategic Directions Committee Appropriateness Criteria Working Group, American College of Radiology, Society of Cardiovascular ComputedTomography, Society for Cardiovascular Magnetic Resonance, American Society of Nuclear Cardiology, North American Society for CardiacImaging, Society for Cardiovascular Angiography and Interventions, and Society of Interventional Radiology. J Am Coll Cardiol. 2006;48:1475-1497.
- Bonow RO, Carabello BA, Chatterjee K, et al. ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: A report of the American College of Cardiology/ American Heart Association Task Force on Practice Guidelines (Writing committee to revise the1998 guidelines for the management of patients with valvular heart disease). J Am Coll Cardiol. 2006;48:e1-148. Erratum in: J Am Coll Cardiol. 2007; 49:1014.
