A 29-year-old female with gradually progressive dyspnea for the last 4 years presented with recent worsening dyspnea and was admitted to the cardiology ICU. On echocardiography, she was found to have rheumatic heart disease with severe mitral valve (MV) stenosis (MV area 0.8cm²), trivial MV regurgitation, mild tricuspid valve regurgitation and with anatomy suitable of percutaneous trans mitral commissurotomy (PTMC).

After initial stabilisation with diuretics and other supportive measures, she was worked up and taken up in the cath lab for PTMC. After giving local anaesthesia, right femoral venous and arterial access was taken followed by 8F & 6F femoral sheath insertion respectively. A 6F pigtail catheter was placed in the non-coronary sinus of the aorta, while a 6F multipurpose catheter advanced over 0.032” wire to the left brachiocephalic vein.

The transseptal puncture was done using a Brockenbrough needle and  coiled wire parked in left atrium (LA) followed by dilatation done using a septal dilator. A 26 mm Accura balloon was advanced over coiled wire to LA. However, MV crossing of the balloon was challenging with stylet and could not be done using standard technique. At this point, one alternative was to remove the balloon assembly over the coiled wire followed by advancing JR or AL catheter across MV, which requires double exchange.

In contrast to other techniques which required double exchange of hardware, we performed the “Single Over the wire Navigation and Balloon Inflation (SONI technique)" as shown in figure 1-3. In this technique, balloon was not removed from the LA. After removing the stretching tube, a 0.035’’x 260cm Terumo wire was advanced through the balloon into the MV to the Left ventricle (LV).The wire was advanced further from LV to cross the aortic valve and was parked into the descending aorta (DTA). However, the balloon could not be navigated across the MV, as it was giving resistance just before MV and further advancement could result in pulling back of the wire. Thus, 0.035’’ wire which was parked in the DTA was snared through the right femoral artery to avoid pulling and thus ensured access.  The balloon was then partially inflated to allow smooth entry near MV orifice, followed by deflation just before entering MV. As the wire was already there across the MV, only with a gentle push balloon was navigated into the LV. Then the balloon was partially inflated and pulled back from LV to place it across the MV followed by full inflation to get the desired result. A successful procedure was done with the splitting of lateral commissure and post-procedure valve area (by planimetry) of 1.8 cm2 and mild mitral regurgitation.

Single over-the-wire navigation and balloon inflation (SONI) Technique for percutaneous trans-mitral-commissurotomy is a bail-out approach for complex cases where crossing the mitral valve cannot be done using standard technique.