Coronary guide catheter and PTCA balloon inflation at OM lesion
Inflation of PTCA (percutaneous transluminal coronary angioplasty) balloon positioned across the stenosis of obtuse marginal (OM) branch of the left circumflex coronary artery. This step was the final step in angioplasty in yesteryears, but now most of the lesions are stented with either a bare metal stent (BMS) or a drug eluting stent (DES). Stenting reduces the chances of acute and subacute vessel closures and also stabilizes dissections if any. The floppy end of the coronary guide wire can be seen distal to the balloon. The guide wire tip can be seen to be curved back on itself, forming a loop. A small distal loop like this prevents wire perforations while advancing the wire. It may be noted that the floppy end of the guide wire is more radiopaque than the rest of the wire. This helps in easy tracking of the guide wire tip fluoroscopically while advancing in order to avoid abnormal tracks and potential complications.
The PTCA balloon inflation is done in a controlled manner using and indeflator which displays the inflation pressure. For each type of balloon there is a nominal inflation pressure at which it achieves the nominal diameter. Usually it is around 6 – 8 atmospheres . If you go beyond that the diameter increases and safety decreases. There is also a rated burst pressure for each balloon. Inflating beyond the rated burst pressure is not advisable. Rated burst pressure one below which 99.9% of balloons will not burst on single inflation. Median burst pressure is the average pressure at which 50% of balloons will burst.