Taking a picture of heart blood vessels (known as coronary artery) is called 'Coronary Angiography' (CAG). Click here for more information on coronary angiography and angioplasty. Your cardiologist may request for CAG if he/she suspects blockages in your heart blood vessels. Such suspicion may arise from routine medical encounter, or if any specific abnormalities are seen in investigations like echocardiogram or stress test. Certain basics of CAG were discussed in my previous blog. Here I will expand the discussion further.
The Procedure:
CAG involves placing a small flexible tube in blood vessel of wrist or groin, through which another long flexible tube (called catheter) is threaded up to the heart. Contrast (or dye) is a special liquid which when injected into heart blood vessel via catheter allows the blood vessels to be seen under x-ray. An animation of angiography can be found here. The Heart foundation summarizes basics of CAG which can be found here.
Basics:
CAG typically takes about 20 minutes of preparation time and another 15 minutes to perform the procedure. CAG can be performed via wrist almost 95% of the time. In 5% of cases, due to various reasons, CAG is done from leg (groin area). Although there are many differences between doing CAG from wrist versus groin, from patient's standpoint basic differences are two: First, groin has slightly higher chance of bleeding. Second, patients need to be on strict bed rest for few hours (typically 4 to 6 hours) after the procedure to reduce the risk of bleeding. Many factors determine which site should be chosen for CAG and should be best left to the performing physician to decide. The procedure is performed in a special suite called Cardiac Catheterization Laboratory (Cath Lab). CAG is typically performed under local anesthesia, with mild sedation to keep patients comfortable. Majority of the patients undergoing CAG experience no or minimal discomfort. Results are available immediately.
Results:
Angiography can have one of the following findings:
1. Normal: This is when heart blood vessels appear normal without any apparent disease or blockages. These patients have very small risk of future heart attack and typically require minimal or no heart medications at all.
2. Mild disease: Here, blood vessels have mild blockages (typically <50%). These patients don't require any stents or bypass surgery but need medications because even low grade blockages have certain risk of progressing in the future. A healthy lifestyle and certain proven medications are standard of care.
3. Significant blockage: When one or more arteries have significant blockage (typically >70%) medicines alone may not able to provide the required benefit. Here, along with lifestyle modifications and medications, stents may be required. Medical decision is tailored to individual patients such that few blockages <70% may require stents based on a particular patient's clinical scenario while there are others with >70% blockage that may not require stent at all.
4. Severe disease: When patients have multiple significant blockages, they are best served with bypass surgery called CABG (Coronary Artery Bypass Grafting). Here also decision making is not at all algorithmic. Location, complexity, age, other medical issues etc. are among few of the patient parameters considered before deciding whether CABG is a good option or not.
Acuity (Urgency of decision making):
An important aspect of CAG is under which circumstances the procedure is done. If CAG is done for active heart attack and reveals major blockage, such situation should be handled in a time sensitive manner. There is continuous cell death during heart attack and delay in opening up a blocked blood vessel increases the incurred damage. Here time is essence and all attempts should be made to quickly halt any further heart damage by opening up the blocked blood vessel as soon as possible. When CAG is done for other indications like chest discomfort but no heart attack, abnormal stress test etc., here we have more time to make a thoughtful decision. In many such scenarios, if significant blockage is identified in one or two blood vessels which are amenable to stents with low risk, its advisable to go ahead with stents in the same setting (ad-hoc) rather than bringing the patient back in for a second procedure (staged). Procedural risks add up with every repeat procedure and should be avoided if possible. More than 90% of all stenting in developed countries are done on ad-hoc basis. When there is any doubt in decision making and there is no active heart attack, it is advisable to pause and seek second opinion with another cardiologist before proceeding with stents or CABG.
Complications:
Since CAG involves catheter movement inside the body, placing the catheter in and around the heart, and injecting contrast, there is always a chance of things not going as planned. With technological advancements and procedural skills, such complications have become quite uncommon. CAG, if done by experts, carries less than 1% risk of major complication, with 99 out of 100 patients completing the procedure without any major issue. There is no down time after the procedure which means most of the activities can be resumed the following day. This is particularly true if the procedure is performed via wrist. There are certain situations where risks of the procedure can be higher than average. Such scenarios demand extra precautions. Inform your doctor if you have any of the following as he/she may be able to do make certain adjustments to the procedure to minimize the risk. Those conditions are: active or past kidney disease, active or past lung disease, active infection (or if you are taking antibiotics), being on blood thinners, allergy to contrast/dye or any other medication, any stents placed in the groin/thigh/leg region, allergy to latex, pregnant women etc. Also, please disclose all the medications you are currently taking to avoid any undesirable medicine interactions.
Things to know:
1. If you plan to seek second opinion after CAG, obtain a CD containing angiography videos. Looking at report alone is not sufficient for any cardiologist to give a sound opinion. WhatsApp images have poor resolution and can't be relied upon for professional opinion.
2. Although there are alternatives to CAG, they all have their limitations, and CAG remains the gold standard.
3. It is ok to ask the operating physician about his/her training and experience in doing CAG.
Things to look out for after CAG:
Please keep an eye on the procedural site (wrist or groin). The area should be kept clean and dry for about 24 hours. It is ok to take a shower after 24 hours. Report to the nearest hospital immediately if you notice rapidly developing swelling, redness, pain, sensation changes etc. Also, any worsening heart related symptoms like chest pain or breathing discomfort, dizziness, excessive nausea vomiting etc. deserves a hospital visit. While likelihood of such things are very low, one should be aware of the possibilities.
If procedure is done through leg then heavy weight lifting (anything more than 5 kg) should be avoided for 48 hours. Similarly, any brisk leg motion like kick starting a motorbike, running up and down the stairs, or kicking a football should be avoided for few days. All these precautions are to ensure no late bleeding occurs at the procedural site.
Drink generous amount of fluids after the procedure for first 24 hours to flush off contrast/dye given during the procedure. Obviously, if instructed by doctor to limit fluid intake, one should follow that. This is done on a case by case basis.
It's likely that this article didn't address all the questions or concerns that you may have about CAG. Feel free to contact me regarding any queries and I will gladly answer those.