Retrograde catheterization to determine degree of aortic valve stenosis significantly increases risk for silent and clinically apparent cerebral embolic events, according to an article in the April 12th issue of the Lancet.

As the authors noted, invasive determination of degree of aortic stenosis can be assessed noninvasively with use of echocardiography. However, retrograde catheterization is often performed as the definitive imaging test, especially for patients who are candidates for valve replacement. The risk for post-procedural cerebral embolic events, especially clinically silent ones, has not been rigorously assessed.

In the current study, German investigators prospectively randomized 152 consecutive patients with aortic valve stenosis at one university hospital to catheterization with (101 patients) or without (51 patients) passage through the valve. All patients received brain magnetic resonance imaging studies and neurological assessment within 48 hours before and after their procedures. A total of 32 patients without valvular stenosis who underwent coronary angiography represented the control group.

Of the101 patients who underwent retrograde catheterization, 22 (22 percent) had signs of an acute cerebral embolic event on their post-procedural imaging test, and 3 had clinically apparent neurological deficits. In contrast, none of the cardiac patients whose study was done without passage through the valve and none of the controls had any evidence of an acute cerebral embolic event in their imaging studies.

The authors wrote, "We have shown that patients undergoing retrograde catheterization of a stenotic aortic valve are at a substantial risk of clinical neurological complications. Furthermore, we noted a far greater frequency of clinically silent cerebral embolic lesions than clinical embolism in these patients. Thus, the substantial risk of structural ischemic brain damage related to the passage of a stenotic aortic valve has been underestimated in the past. We should inform patients about these procedure-related risks, and retrograde catheterization of the stenotic aortic valve should only be undertaken when patients' echocardiographic findings are unclear and additional information is essential for clinical management."