Coronary Angiography: a technique to diagnose arterial blockage and prevent heart attack

By Dr Ranganath Nayak,

Heart attacks are becoming more common in young people specially in Indian context where data has shown that 20 to 25% of the attacks are in the age group of below 45 years. The best way to diagnose and prevent them is to undergo a scheduled check-up and not ignore the symptoms.

BACKGROUND

Coronary arteries supply blood to the heart. These arteries are prone to narrowing or complete blockage due to the deposition of cholesterol or plaque with super added clot. It results in reduced blood supply to the heart causing heart attack. Coronary angiography is a technique to determine the presence, size, and extent of blockage in the coronary arteries.  

Coronary angiography is an imaging technique for evaluating the health of coronary arteries. Coronary angiography is a minimally invasive procedure and helps to determine the presence of any blockage. Injectable dye and X-rays assist in creating detailed images of the coronary artery. The patient experiences no or little pain during the technique. 

INDICATIONS

Coronary angiography may be recommended in the following conditions:

• Symptoms of coronary artery disease, such as chest pain radiating to the jaws, neck or arms, chest heaviness, breathlessness, dizziness, unconsciousness, etc
• Non-invasive heart stress test results are abnormal
• Heart valve problem that requires surgical intervention

TECHNIQUE

Conventional angiography is the oldest form of angiography which involves passing a catheter to the heart through a blood vessel located in the wrist or groin region.  A special dye is injected through the catheter inserted into the coronary vessels to identify the blockage in the blood vessels. 

The doctor obtains necessary information about the health of the coronary artery. The result may interpret:

• The number of vessels affected with the plaque

• Site and severity of blockage in the coronary artery

• The success of the previously performed bypass surgery / Angioplasty.

A non-invasive form of coronary angiogram is called CT coronary angiogram the dye is injected rapidly in a peripheral vein.  A series of X-rays are taken as the dye flows through the blood vessels to create images which are commonly known as angiograms.  With the advancement of medical technology, it is now possible to combine traditional angiography with a CT scan or MRI that enables higher resolution imaging which is sensitive to detect changes in muscle and structural defects. The procedure takes about 30 mins to 2 hours and the patient is usually discharged on the same day.

PROCEDURE

Before the procedure, the team at the hospital will comprehensively evaluate the patient symptoms and clinical findings to determine if the patient is fit for an angiography. The team will go through the medical history to seek information about the drug allergies. 

The procedure is carried out in a specialised hospital setting known as a Catheterisation Laboratory (Cath Lab). The patient is mildly sedated to help him/her relax but remains conscious throughout the procedure. During the procedure, the patient is connected to an ECG to monitor the functioning of the heart. A small cut is made in one of the arteries in the groin or wrist area and a very thin flexible tube known as a catheter is inserted through it to reach the blood vessel under examination. Local anaesthesia is used to make the procedure painless. A dye is injected into the catheter and a series of X-rays are taken. 

After the angiogram, the doctor removes the catheter and closes the incision. The paramedical staffs shift the patients into the recovery area where the patient is under continuous monitoring. The doctor discharges the patients once the vital parameters are stable. 

RECOVERY 

The nursing staffs provide detailed instructions during discharge about how to take care at home. The patient may be advised to apply pressure on the injection site for some time to avoid bleeding and drink plenty of water to flush out the dye. The patient should also avoid strenuous exercise or lifting heavy weights for a few days.

RISKS AND SIDE EFFECTS

Side-effects are mild, but rarely may lead to

• Injury to the artery at the site of injection
• Infection
• Excessive bleeding
• Allergic reactions to dye or other medications used during the procedure
• Heart attack and stroke
• Kidney injury
• Irregular heartbeats
• Low blood pressure

The patients are advised to seek immediate medical help post-procedure if they 

• Experiences numbness or weakness in the hand or leg 
• Redness, infection, or abscess at the site of injection
• Chest pain
• Bleeding at the site of injection .

(The author is the Consultant Cardiologist at Manipal Hospital, Millers Road. The article is for informational purposes only. Please consult medical experts and health professionals before starting any therapy, medication and/or remedy. Views expressed are personal and do not reflect the official position or policy of the Financial Express Online.)