Angioplasty stent

Is stenting superior to conventional angioplasty?

Balloon expandable stents were introduced to prevent complications and sudden closure after ordinary angioplasty. The stent was first approved by Food and Drug Administration (FDA) in 1992 for the emergency management of abrupt vessel closure after angioplasty the so called bailout indication. But few trials have proved tant routine placement of stent (not bail out stenting) may reduce the restenosis rate of angioplysty, which is a great draw back of conventional PTCA. Some studies has document that stenting may reduce the incidence of restenosis after the procedure. In one study restenosis rate was 32% in conventional angioplasty and 22% in stentiion group and in another study restenosis rate was 43% in angioplasty patients and 30% in stented patients. So it is believed that coronary stenitng may be superior to ordinary balloon angioplasty and can reduce reocclusion rate significantly.

What is stent

What is a stent?

A coronary stent is a small, stotted, stainless steel tube mounted on a balloon catheter. It looks like a spring used in ordinary ball pen. It is introduced into the artery just after balloon angioplasty into the artery just after balloon angioplasty and is positioned at the site of the obstruction. The procedure is almost lie balloon angioplasty, so the patient can not understand the difference between ordinary stenting. The stent remains wrapped around the deflated balloon. When the balloon is inflated, the stent expands and is pressed against the inner walls of the coronary artery. After the balloon is deflated and removed, the stent remains in place, keeping patients artery. It helps to old the artery open, improves blood flow and relieves symptoms of chest pain.

During the first few days of stent implantation, the daily activities well are restricted. The patient must lie flat until the day following the procedure. The patient will stay in the hospital for up to 2 to 8 days before being discharged. If the patient experienced any chest discomfort, pain or bleeding of any kind after returning home, he/she should contact the doctor or hospital immediately. After 6 months the patients may be asked to return to hospital for a follow-up stress test/check coronary angiogram.

There are many types of stent at present in use. They are Gianturco-Roubin, Palmaz-Schatz, Wallstent, Medronic- Wiktor stents, Bard XT, AVE stent etc. All stents mentioned above are made of stainless steel except Wiktor stent which is made of Tantalum. All the stents are thrombogenic so it may re-occlude after placement. So it is extremely important to follow the medication exactly after implantation of a stent. These medicines keep the blood thin and prevent re-occlusion. Within about four weeks, the lining of the artery slowly grows over the stent, incorporating it into he arterial wall. During this time the patient must be treated with medications to thin the blood and to prevent blood clogging inside the metal surface of the stent. At earlier days combination of aspirin, warfarin and dipyridamole were used to prevent stent occlusion. But now the trend has changed. Now-a-days warfarin or coumadin are not used routinely. Combination of aspirin and ticlopidine has been proved more superior than aspirin and warfarim combination. Patient is advised to take ticlopidine 250 mg twice daily and aspirin combination for 4-8 weeks then only aspirin indefinitely. Any patient taking ticlopidine must check his blood count at an interval of 2 weeks to 1 month because white cell count may fall in 1-2% of patients taking this drug. Combination of aspirin and clopidogrel (plavix) 75 mg once a day may be used instead of combination of aspirin and ticlopidine.

Cardiac Stent

Advice to a stent patient

1.     You must follow your medications erectly.

2.     Do not stop taking any of the prescribed medicines unless you are instructed to do so by the doctor who implanted the doctor who implanted the stent.

3.     If you experience any side effects of the medications, such as headaches, nauseas, vomiting or skin rash, notify your doctor immediately.

4.     After stent implantation, if you develop chest pain or dyspnea immediately report to your doctor.

5.     Keep all appointments for follow-up care including blood testing.

6.     Do not go for a magnetic resonance imaging (MIR) scan within 8 weeks of stent implantation with out clearance from your cardiologist.

7.     Do not use antacids routinely unless prescribed by your doctor, as antacid decrease the absorption of aspirin.

Echocardiogram

Echo-cardiogram test

Echocardiogram is nothing but cardiac ultrasonography. In this sophisticated technique sound waves are used for direct visualization of heart. Doctors can see or scan the heart in a screen, which is almost like television screen. So echocardiogram is the technique of ultrasound imaging of the living heart using ultrasound waves to image various structures within the heart. It is a noninvasive procedure so patient does not feel any pain during echocardiography. Not only the doctor, but also the patient can see his heart movement in the television screen during the procedure. This technique provides detailed anatomical information on cardiac chambers, valves, holes in the heart, abnormal fluid collection around the heart and abnormal intracardiac masses such as tumors, blood clot and infective material. In this procedure a hand-held transducer housing the ultrasound crystal is applied to the patient’s anterior (front) chest wall. Through this, a beam of ultrasound waves is transmitted into the patient’s heart and the returning echoes are then converted into images which are displayed on a video monitor to be recorded on tape in real-time for easy play-back and hard-copy print-out. Doctor can take multiple two dimensional pictures of heart in different positions during the procedure. Doppler echocardiography is used along with the two dimensional echocardiography for detecting flow direction, for measuring blood flow velocity and pressure gradient. Now a day, through colour Doppler imaging, doctor can see the actual blood flow in and around the heart. Obstruction of the values and any trivial leaking can also be demonstrated by colour flow imaging. Heart can also be scanned by using transesophageal echocardiography. Here, the ultrasound crystal is mounted at the tip of an endoscope which is similar to that used by gastroenterologists for studying the stomach and intestines. This tube is introduced through the patient’s mouth in to the esophagus (food-pipe) which lies immediately behind the heart. This technique is usually used when conventional transthoracic (through external chest wall) images are technically suboptimal or inadequate for definitive interpretation.

In patients with coronary heart disease echocardiography usually detect left ventricular wall motion abnormality. In a patient with history of previous heart attack, echo can demonstrate that the wall affected previously either is not moving at all or contracting sub normally. So this procedure is an excellent diagnostic tool for assessing left ventricular function (heart pump function). But in patients with only angina pectoris with out any previous heart attack echo may not show any abnormality. So a normal echo study does not exclude the possibility of significant block in coronary circulation. But newer technique which is called tress echo can detect angina pectoris by stressing the heart and simultaneously real time imaging of heart function. Echocardiography can also document blood clot (solidified blood) inside heart. Now a day’s bed side echocardiography is used to diagnose heart attack at a very early stage when ECG interpretation gives equivocal result.