Coronary angioplasty and thrombolysis – The interventions that protect your heart || Part 2

Cardiovascular disease is responsible for major mortality rates, of which acute myocardial infarction is the most prominent condition. Until a few years ago, mortality rate due to acute myocardial infarction was extremely high, as was the severe outcome for survivors. New cardiac intervention techniques, such as angioplasty, revolutionised this scenario. During the past decade the Hospital Particular in Alvor has played an important role in this area with the vast experience it has gained with its Hemodynamic Laboratory.

Once the diagnosis of acute myocardial infarction is confirmed, treatment consists in restoring blood flow in the shortest period of time possible.

There are two possible ways of doing this, both with advantages and disadvantages: thrombolytic medical therapy (intravenous drugs, explained in the previous article) and angioplasty (a mechanical procedure). In both cases the object is to remove the blood clot which is causing the obstruction.

A cardiac angioplasty is performed when a catheter is introduced in the main artery to try restoring coronary circulation. It is then possible to introduce a balloon positioned at the tip of the catheter in the narrowed artery which is then inflated, increasing the diameter of the artery. This procedure can solve the tightening of the artery or stenosis in the acute stage, subsequently unblocking the coronary artery. In the long term, in the majority of cases the artery becomes blocked again (restenosis) and complications arise.

An Angioplasty consists of the introduction of a small 2mm diameter catheter (tube) which is inserted into the artery in the inguinal region, under local anaesthesia. A contrast is then injected into the coronary arteries using this catheter, which is then viewed by radiology in order to detect where exactly the obstruction is located.

Once the location is detected, a guide wire is inserted into the artery in order to pierce the clot, which is then placed distally to the obstruction. Through this wire a balloon is introduced, which then crushes the obstructive clot, and finally a metal ring called a stent is introduced subsequently, allowing the restoration of the coronary circulation.

Initially, angioplasty was performed only with balloon catheters, but technical advances have been made and improved patient outcome has been achieved with the placement of small metallic spring-like devices called stents.

A successful angioplasty can reduce the mortality rate after a myocardial infarction by 1/3 or 1/4 compared to what would be the case if this procedure was not used.

Approximately 5 to 10% of patients will experience an obstruction of the implanted stent. This phenomenon is the result of an abnormal healing mechanism known as restenosis and normally occurs in the first year after a stent implant, although its prevalence has been greatly reduced by the use of stents impregnated with anti-proliferative drugs.

Despite the efficient results of an angioplasty, patients in the acute stages of the disease submitted to this intervention need to be regularly monitored by their cardiologist.

Clinical trials comparing thrombolytic therapy and angioplasty, have been more favourable to angioplasty, namely by reducing complications such as haemorrhages and re-infarction.

However, in some patients it may not be technically possible to perform an angioplasty and the only treatment possible may be medical therapy in order to prevent a myocardial infarction and its complications, or coronary surgery to create alternative pathways for the passage of blood, known as coronary artery bypass.

Currently, the average hospital stay for a myocardial infarction, when there are no associated complications is five to seven days. This period is important as it is during this phase that most complications occur where an effective treatment is only possible in a hospital setting.

The most frequent complications are arrhythmias and heart failure resulting from damage to the heart muscle and scar tissue.

The only limitation in using this technique is the need for a Hemodynamic Laboratory and a highly-trained professional team. The HPA in Alvor was the first hospital in the Algarve to have this type of laboratory, which has been operational since 2001. This has permitted many lives to be saved in the Algarve.

Article written by the team of cardiologists of the HPA Health Group