Here is an illustrated review of steps in percutaneous transluminal coronary angioplasty (PTCA) of left anterior descending (LAD) coronary artery:
Balloon inflation in LAD
Guide wire is cautiously passed across the total occlusion taking care that it does not produce a false lumen. If the wire is able to pass back and forth easily into multiple side branches, we can be sure that the wire is in the true lumen. There should not any contrast staining or extravasation with check shots of angio. Balloon is passed over the guidewire and inflated and deflated with the indeflator. Patient status and ST segment on the ECG monitor are watched during inflation, though no change is likely while inflating a total occlusion. If it was a near total occlusion or tight stenosis, there is a high chance of angina, ST shift and even hypotension or arrhythmia during balloon inflation, especially if it is prolonged. The deflated balloon is then removed from the coronary artery and the catheter slowly, under negative pressure, taking care not to displace the guidewire.
Check angio after balloon dilatation of LAD
Check angiogram after balloon dilatation of LAD shows good flow throughout the extent of LAD, also visualising the side branches. Now the vessel is ready for stent insertion after measuring the size of the lesion (length and diameter). If the lesion is not fully expanded after the initial balloon inflation, serial dilatation with different sizes of balloon may be used, with due precautions to avoid vessel injury like dissection and perforation. In some cases, if the lesion is calcified, rotablation using the diamond burr of a rotablator may be needed for preparing the lesion for stenting. Inadequate lesion preparation often leads to incomplete stent apposition, enhancing the risk of stent thrombosis and symptomatic restenosis.
LAD after stent insertion and balloon dilatation
The pre dilatation balloon is removed and the balloon mounted stent is inserted over the guide wire. The stent balloon is inflated to the rated nominal pressure and sometimes even beyond that level, taking care not to exceed the rated burst pressure. Balloon inflation pressure is monitored in the pressure gauge attached to the indeflator.The stent balloon is deflated and removed under negative suction. Check angio after stent expansion shows good TIMI 3 flow and the stented segment stands out as a slight bulge in the vessel profile at the distal end. The bulge is because of the natural tapering of the vessel from the proximal to distal portion of the stent. If the stent is not fully expanded, serial post dilatations with noncompliant balloons are given. Use of intravascular ultrasound (IVUS) is beneficial in recognizing good stent apposition. Use of IVUS to assess stent apposition is desirable in critical positions like the left main coronary artery as incomplete apposition leads to suboptimal lumen improvement and enhances the potential for catastrophic stent thrombosis.