Should we cross the valve: the risk of retrograde catheterization of the left ventricle in patients with aortic stenosis.

CLINICAL SCENARIO: A 67-year-old man is referred to your cardiology clinic complaining of worsening angina and dyspnea on exertion. Physical examination reveals a harsh grade IV/VI late-peaking crescendo-decresendo systolic murmur, loudest at the upper sternal border. The aortic closure sound is diminished. Echocardiography demonstrates left ventricular hypertrophy, an ejection fraction of 50%, no evidence of mitral regurgitation, and severe aortic stenosis (AS) with a peak aortic gradient of 4.8 m/s (92 mm Hg) and a mean aortic gradient of 55 mm Hg. You schedule him for coronary angiography but wonder whether you should reevaluate his aortic valve gradient invasively. LITERATURE SEARCH: Combining the keywords "aortic valve stenosis" and "heart catheterization/adverse effects," you find 72 articles. From these you choose the following: Omran H, Schmidt H, Hackenbroch M, et al. Silent and apparent cerebral embolism after retrograde catheterization of the aortic valve in valvular stenosis: a prospective randomized study. Lancet 2003;361:1241-6. QUESTION: What is the stroke risk of retrograde catheterization of the aortic valve in patients with AS?
DESIGN: The study was prospective and randomized; unblinded treatment but with blinded assessment of outcomes.
SETTING: The study was conducted at a single center in Bonn, Germany. PATIENTS: A total of 152 patients with known or suspected AS undergoing cardiac catheterization were randomized to catheterization with or without retrograde passage of the aortic valve in a 2:1 randomization format. Patients underwent brain magnetic resonance imaging (MRI) the day before and within 48 hours after cardiac catheterization. Patients with unclear echo findings or contraindications to MRI or transesophageal echocardiography were excluded. There were no significant baseline differences between the 2 groups: mean age 70.5 years, left ventricular ejection fraction 62%, and mean aortic valve gradient 51 mm Hg. All patients were evaluated in the groups to which they had been randomized and, other than the experimental intervention, the 2 groups were treated similarly (with the exception of the administration of 5000 units of intravenous heparin to the group receiving retrograde aortic catheterization). A control group of 32 patients without aortic valvular stenosis was evaluated as well. INTERVENTION: The intervention consisted of retrograde passage of the aortic valve for the purpose of obtaining an invasive aortic valve pressure gradient. MAIN OUTCOME MEASURES: The main outcome measures were acute cerebral embolic events, defined by MRI findings within 48 hours after catheterization (as compared to precatheterization MRI) and by clinical examination. MAIN
RESULTS: Twenty-two of 101 patients (22%) assigned to retrograde catheterization developed new focal MRI abnormalities consistent with acute cerebral embolic events. Three of these patients (3%) demonstrated clinically apparent neurologic deficits. None of the patients who did not undergo retrograde catheterization--and none of the control patients--had MRI or clinical evidence of cerebral embolism.

RCT Entities:   Population Interventions Outcomes