Coronary angioplasty – unclog your blood vessels: Coronary arteries are blood vessels supplying oxygenated blood to the heart. Blockage of these vessels abruptly results in a heart attack (acute myocardial infarction). Percutaneous Transluminal Coronary Angioplasty (PTCA) or just coronary angioplasty for short, is the procedure in which small balloons attached to the tip of small tubes are used to remove the blocks in coronary arteries. Percutaneous Transluminal Coronary Angioplasty (PTCA) was originally described by Andreas Gruentzig in 1975. He used balloon catheters to dilate narrowed coronary arteries. PTCA success rates and quality of hardware have improved a lot from the days of Gruentzig.
A small opening is made under local anaesthesia in the groin or at the wrist for introducing small tubes known as angiographic catheters to inject radiocontrast dye to the coronary arteries. The cine X-ray video of passage of the dye across the coronary arteries is known as coronary angiogram. After diagnostic coronary angiography has localised the lesion(block in the coronary artery), a guide catheter (a tube with a better lumen and wall thickness than the catheter used for diagnostic angiography) is introduced and kept in the opening of the involved artery. Guide catheters have a wider lumen and braided wall to give better support. A guide wire is introduced into the culprit vessel using a manifold and connector. The wire is gently pushed and if necessary rotated with torquer to cross the coronary lesion (obstruction). Once the floppy tip of the guide wire has crossed the lesion, it is introduced further down the vessel, well beyond the obstruction. Check injections of contrast through the guide catheter enables visualisation of the coronary arteries to show the final position of the guide wire. Once the guide wire is in position, a balloon catheter is threaded over the guidewire and the balloon is positioned across the lesion. After verifying the position of the balloon across the lesion, it is inflated using an indeflator (inflation deflation device with a pressure gauge). The inflation pressure is monitored in the pressure gauge attached to the indeflator. Care is taken to avoid exceeding the rated burst pressure of the balloon. After maintaining the inflation for about 20 seconds, the balloon is deflated and placed on negative pressure. The balloon is gradually withdrawn and check injection of contrast given to visualise the result of balloon angioplasty. In the earlier days, only plain balloon angioplasty was being practiced, while now-a-days, most balloon dilatations are followed by stenting to prevent vessel recoil and abrupt closure. Stents are tiny spring like metal structures which scaffold the coronary artery lesion after balloon dilatation. Newer stents have medicines to prevent reformation of the blocks instilled into them. These are known as drug eluting stents, in contrast to bare metal stents. Stenting is also useful in walling off dissections if any, which had occurred during balloon dilatation.
Bioabsorbable stents (bioabsorbable vascular scaffolds) have also been developed. These get reabsorbed after a few months leaving the vessel in its natural structure so that the sharp angles affecting the smooth flow of blood when usual stents are implanted are avoided. Moreover there is no foreign body remaining in the blood vessel after a certain period. But these stents did not become popular due to poor long term results in spite of higher costs.