Clinical outcome of transcatheter aortic valve implantation in patients with low-flow, low gradient aortic stenosis.

BACKGROUND: Low-flow, low-gradient aortic stenosis is associated with relevant postoperative mortality whereas conservative management results in dismal prognosis. We present the initial experience of low-flow, low-gradient aortic stenosis treated with transcatheter aortic valve implantation (TAVI).

METHODS: From June 2008 to December 2010 167 consecutive patients with native severe aortic stenosis and an excessive operative risk underwent TAVI. Of these, 15 patients presented with low-flow, low-gradient aortic stenosis (aortic valve area < 1 cm(2) , left ventricular (LV) ejection fraction < 40%, aortic mean gradient < 40 mm Hg). The CoreValve prosthesis 18-F-generation (Medtronic, Minneapolis, Minnesota) was inserted retrograde. Clinical follow-up and echocardiography were performed 6 months after procedure.

RESULTS: Patients with low-flow, low-gradient aortic stenosis (mean LV ejection fraction 32 ± 6%, mean aortic gradient 27 ± 7 mm Hg) had higher all-cause mortality 6 months after TAVI compared to patients without low-flow, low-gradient aortic stenosis (33% vs. 13%, P = 0.037). In the surviving 10 patients with low-flow, low-gradient aortic stenosis, LV ejection fraction increased (34 ± 6% before vs. 46 ± 11% 6 months after TAVI, p = 0.005) and more distance covered in the 6-minute walk test (218 ± 102 meters before vs. 288 ± 129 meters 6 months after TAVI, p = 0.038).

CONCLUSION: Our study suggests that TAVI is feasible in patients with severe co-morbidities and low-flow, low-gradient aortic stenosis. Within the first 6 months after treatment all-cause mortality was considerable high, but the surviving patients showed symptomatic benefit and significant improvement of myocardial function and exercise capacity.