TAVI without predilation
Transcatheter aortic valve implantation (TAVI) is being accepted more and more as an effective treatment for severe symptomatic aortic stenosis in patients at high surgical risk. Technical success rates have risen to 97 percent in some series. The important complications are AV conduction problems requiring permanent pacemaker implantation, paravalvar regurgitation, complications at access sites and embolic manifestations. Embolic stroke is due to the fragments of the degenerated valve material released into the circulation during the predilation of the stenosed valve. Conduction disturbances can also be attributed to the predilation as the conduction system is close to the aortic annulus.
Grube E and associates conducted a pilot study to know the feasibility of TAVI without balloon predilation . TAVI without predilation would theoretically reduce the embolic complications and complete heart block. So far, performing balloon valvuloplasty prior to device placement has been considered mandatory to facilitate good device implantation and to reduce the radial radial counterforce which might prevent optimal device expansion. In addition to embolic episodes and complete heart block, balloon dilation also lead to hemodynamically significant severe aortic regurgitation in some cases.
In this study by Grube et al, a total of sixty patients with a mean age of around eighty years underwent TAVI using a self expanding device at thirteen international centers. They could achieve a reduction of mean gradients from about fifty to four. The final valve orifice was circular in 41 cases and non circular in 19 cases. Both had good improvement in valve areas from a mean of about 0.67 square centimeter to about 1.7 square centimeter. In hospital mortality was 6.7 percent, there were no myocardial infarctions and there was a 5 percent incidence of stroke. Major vascular complication occurred in ten percent of patients. New permanent pacing was required in 11.7 percent. The authors conclude that TAVI without balloon predilation is feasible and safe with similar acute safety and efficacy as compared with current standard procedure with predilation. Seventeen percent of cases in this series needed post dilatation, which is similar to that in other conventional series. High frequency temporary ventricular pacing, which is usually performed during balloon valvuloplasty to reduce the movements of the heart is not needed in this new approach. This may have an advantage in this patient population who is already compromised by heart failure or reduced ejection fraction.
- Grube, Naber C, Abizaid A, Sousa E, Mendiz O, Lemos P, Kalil Filho R, Mangione J, Buellesfeld L. Feasibility of Transcatheter Aortic Valve Implantation Without Balloon Pre-Dilation. JACC Cardiovasc Interv. 2011 Jul;4(7):751-7