Hidden dangers of coronary angioplasty and stenting


  • Letters
  • Monday, 24 Nov 2003

I READ with interest the letter from Dr T.S. Tan and Dr T.K. Khoo, Better to leave it to the cardiologists to choose the best procedure(The Star, Nov 6), emphasising the safety and benefits of coronary angioplasty and stenting as compared to surgery. 

Recently, a study from the Cleveland Clinic in the United States looked at the effects of coronary angioplasty and stenting in patients undergoing elective procedures and who did not have myocardial infarction to begin with.  

Of 8,490 patients, 17.2 % had evidence of myocardial damage as determined by the increase in cardiac enzymes. 

These patients were found to be at a higher risk of death in the first four months following the procedure. 

The risk increases the higher the enzyme level is detected. The actuarial four-month risk of death was a staggering 8.9% in patients who had more than a five-fold increase in the level of the enzymes. 

Many of these deaths would have occurred after the patients had been discharged from the hospital, since most of these patients only stayed in hospitals for one to two days following coronary angioplasty and stenting. 

Coronary angioplasty and stenting, although superficially relatively non-invasive since the skin puncture is only a few millimetres in diameter, may well be more challenging internally. 

First, cardiologists have to introduce catheters, wires, balloons and metallic stents into the body. Patients invariably end up with more metal bits in their coronary arteries at the end of the procedures. 

Furthermore, since coronary arteries do not show up on X-ray screens, cardiologists have to inject contrast into the body to see the coronary arteries. 

All these are potentially hazardous to the body. 

Avoiding surgery is one of the strongest argument put forward to gullible patients to induce them to undergo coronary angioplasty and stenting. 

The American Heart Association guidelines on management of patients undergoing coronary angioplasty and stenting listed, in addition to myocardial infarction and death, the following risks associated with this procedure. 

Firstly, allergic reactions to the iodine-based contrast agents used during the procedure. 

This is particularly important in patients with a previous history of allergic reaction to contrast, where the risk is 17% to 35%.  

Also, as the result of using a large amount of contrast medium, patients can develop constrast-induced nephropathy. 

This is especially important in diabetic patients with pre-existing renal disease where the risk of renal damage is 11% to41%. 

The risk appears to be related to the amount of contrast used. In treating high-risk patients with multiple diseased vessels, cardiologists sometimes are forced to use a large amount of contrast. 

Many patients with coronary artery disease have pre-existing arterial disease elsewhere in the circulation. 

Since cardiologists can only get to the coronary arteries from another, far away artery, they have to introduce various implements into the circulation. 

Vascular complications are ever present. Excessive bleeding occurs in 0.7% to 1.7% of patients. Groin or retroperitoneal haematomas may occur in 0.15% to 0.44%.  

Stroke can occur in 0.1% to 0.38% of patients undergoing coronary angioplasty and stenting. About half of these strokes are haemorrhagic. 

The major complication, however, is the restenosis or renarrowing of the coronary artery following coronary angioplasty and stenting. 

Even in patients with single vessel disease, the benefits from surgery are evident in reducing the need for repeat procedures. 

If the initial cost of the coronary stenting already doubles that of surgery, surely patients should be made aware of the financial implications of his treatment. 

 

ENG JI BAH, 

Cardiothoracic Surgeon, 

Penang. 

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