Lithotripsy

[George K]

When I was finishing my training, and in the early years of practice, the ability of cardiologists to perform an "angioplasty" was just coming into common use.

Angioplasty greatly reduced the need for open heart surgery. The technique, simply put, involves passing a wire past the lesion in the coronary artery. Built into the catheter/wire, is a balloon. The balloon is inflated, frequently fracturing the plaque and potentially opening the obstructed artery. It was revolutionary, but not without risk. Rupture of the coronary artery by high pressure in the ballon and inability to cross the lesion were sources of concern. In the early days, whenever an angioplasty was performed, the open-heart team was "on call", required to stay in house, until the procedure was completed, should a disaster occur. Fortunately these were uncommon, and after a few years, the need for backup became remote.

Link to video

The next big advance was the development of technology to insert a stent, basically a tube, across the lesion, preventing, it's hoped, the vessel from closing down after an angioplasty. THere's been all kinds of science on the material for stents - bare metal, drug-eluting, etc. However, the risks of angioplasty were still there.

Lithotripsy was first used in treating kidney stones, and our practice had the contract with a local stone center for ESWL (Extra-corporeal Shockwave Lithotripsy). I've given anesthesia for hundreds of these cases - as many as 55 in one week sometimes. It's been tried in treating gallstones, but met with failure because breaking up the stone frequently caused sludge which could obstruct the bile ducts.

Today, I saw that Boston Scientific has bought a company that does intravascular lithotripsy. Apparently, it's used for treating peripheral artery disease as well as coronary artery disease.

Cool beans.

Link to video

[Jolly]

Had a good friend who wanted the medicated stints so badly, he had another MI before he got them. Those two extra weeks weren't worth it.

[George K]

By the way, wrt kidney stones, in the last 10 years or so, the use of ESWL has dropped off dramatically. Today's urologists are trained to snag the stone using ureteroscopy and other non-invasive techniques. Much higher success rate. With ESWL, you're looking at about a 20% need for redo. When the only other option was to have a major operation (pyelolithotomy or ureterolithotomy), it was a good choice.

Today, not so much.

I haven't looked or asked, but the kidney stone center where we worked and did up to 50 cases a week is no longer profitable, and there are rumors of it shutting down.

[jon-nyc]

ureteroscopy and other non-invasive techniques

Sorry dude. Putting a scope up my johnson is the polar opposite of non-invasive.

[George K]

@jon-nyc You said "Pole-ar"...lol.

[Axtremus]

@George-K said in Lithotripsy:

Today, I saw that Boston Scientific has bought a company that does intravascular lithotripsy. Apparently, it's used for treating peripheral artery disease as well as coronary artery disease.

It's cool. The video says it modifies the calcium structure. I take that means it will not be useful where there blockage/constriction is not caused by calcium, is that right?

Are artery diseases mostly caused by substances with calcium?

[jon-nyc]

George - what happens to the calcium bits that get dislodged? Filtered in the kidneys? Any risk of large pieces doing damage either at the kidney or along the way?

[George K]

@Axtremus said in Lithotripsy:

Are artery diseases mostly caused by substances with calcium?

ChatGPT:

Artery diseases, particularly atherosclerosis (the buildup of plaque in the arteries), are often influenced by several factors, and while calcium plays a role in the process, it is not the only cause. Atherosclerosis is primarily driven by the buildup of a combination of substances inside the arterial walls, including:

1. Cholesterol:
   • Low-density lipoprotein (LDL) cholesterol is commonly known as “bad” cholesterol, and when it accumulates in the artery walls, it can lead to plaque formation.
   • High-density lipoprotein (HDL) cholesterol, or “good” cholesterol, helps remove excess cholesterol from the bloodstream, but its levels can be affected by lifestyle and genetics.

2. Fatty Deposits:
   • Saturated fats and trans fats in the diet can lead to the accumulation of fatty deposits in the blood vessels, contributing to plaque buildup.

3. Calcium:
   • Calcium is an essential mineral, but in atherosclerosis, it can accumulate in the plaque that forms in the arteries, making the plaque harder and less flexible.
   • This calcification of plaque can lead to the narrowing and stiffening of the arteries, restricting blood flow and increasing the risk of heart attacks, strokes, and other cardiovascular events.

4. Other Substances:
   • Inflammation: Chronic inflammation in the body can contribute to the development of plaque in the arteries. Inflammatory molecules can encourage the buildup of fatty deposits and calcium in the arterial walls.
   • Sugar: High blood sugar levels, especially in conditions like diabetes, can damage the lining of blood vessels and promote plaque buildup.
   • Toxins: Smoking and exposure to environmental toxins can also damage the arteries, making them more prone to plaque formation.

5. Risk Factors:
   • Several factors increase the risk of developing artery disease, including smoking, high blood pressure, high cholesterol, lack of physical activity, poor diet, and genetic predisposition.

Summary:

While calcium does contribute to the calcification of arterial plaque in conditions like atherosclerosis, the development of artery diseases is multifactorial. It results from a combination of genetic, lifestyle, and environmental factors, and other substances like cholesterol and fats also play a significant role in the process.

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My take: It's a multifactorial process, with calcium being an important competent of arterial disease. One leads to another. This is far out of my area of expertise, but at least I understand the language.

[George K]

@jon-nyc said in Lithotripsy:

George - what happens to the calcium bits that get dislodged? Filtered in the kidneys? Any risk of large pieces doing damage either at the kidney or along the way?

In the case of arterial disease, the embolization of calcium is insignificant in obstruction of blood flow, according to the folks that are promoting this. The "pieces" are small enough to not be of concern.

In the case of urologic ESWL, there are standards for how things should be handled. If a stone is >2 cm in size, a ureteral stent (a tube that goes from renal pelvis to bladder) should be inserted to allow fragments of the stone to pass down the ureter while urine flow is unobstructed due to the stent.