Ⅰ. Basic situation of coronary balloon angioplasty
1. Overview
Coronary balloon angioplasty is an interventional treatment method in which the balloon dilation catheter is delivered to the target lesion of the coronary artery along the guide wire track, and the balloon is pressurized and filled to generate expansion force to dilate the narrowed coronary artery, which is also the basis of all interventional treatment techniques for coronary heart disease.
The role of balloon dilatation catheter (balloon for short) in PCI has gradually expanded from the initial simple balloon angioplasty (POBA), and has been endowed with many functions such as lesion pre-expansion, auxiliary stent delivery and post-expansion, and drug-loaded (drug-coated balloon, DCB) treatment.
Balloons are divided into compliance, semi-compliance and non-compliance balloons according to design characteristics; rapid exchange and overall exchange balloons (OTW) according to operating characteristics; according to special functions, they have developed from perfusion balloons before the advent of stents to new balloon series such as cutting balloon, spinous process balloon, double guide wire balloon and DCB are commonly used in clinical practice at present.
2. Technical characteristics
(1) Basic composition: The structure of the coronary balloon dilatation catheter includes the tip, the balloon, the transition section, and the pusher rod, all of which are closely related to the passage of the balloon.
(2) Compliance: Compliance refers to the ability of the balloon diameter to change with pressure.
(3) Pushability: it refers to the ability of the balloon dilatation catheter to push the balloon forward, which mainly depends on the design of the tip of the balloon and the transition zone and the material of the push rod. The larger the pushability, the better.
(4) Flexibility: Flexibility refers to the ability of the balloon catheter to follow the curved blood vessel.
(5) Basic parameters of the balloon:
3. Indications and contraindications
(1) Applicable situations:
① POBA is the earliest interventional treatment method, but the restenosis rate is as high as 30% to 60%;
②Balloon pre-dilation is suitable for the pretreatment of most lesions before stent implantation, and can also assist in the measurement of vessel diameter, assessment of lesion length, and understanding of the nature of lesions to a certain extent;
③Balloon post-expansion is mainly suitable for further high-pressure expansion in the stent after stent implantation to ensure complete expansion and wall attachment of the stent. ④ DCB, also known as drug-eluting balloon, releases anti-proliferative drugs locally to the coronary artery wall while the balloon is inflated, so as to achieve the effect of inhibiting vascular intimal hyperplasia.
(2) Not applicable:
①Coronary artery stenosis <50%, without objective evidence of myocardial ischemia;
②For severe multivessel diffuse disease, simple balloon dilatation or stent implantation is not effective, while coronary artery bypass surgery is safer and has a better prognosis.
4. Operating procedures and technical points
Rapidly exchanged monorail balloons are currently the most widely used. The following takes monorail balloons as an example to introduce the operating procedures and technical points of balloon dilation.
(1) Select the appropriate coronary balloon catheter.
(2) Feed the balloon catheter along the guide wire.
(3) Avoid repeated forceful angiography after pre-dilation, so as not to aggravate the tearing of blood vessels.
(4) For lesions with severe stenosis and complex lesions, or when stent passage is expected to be difficult, adequate pre-dilation should be routinely performed.
(5) The post-expansion balloon after stent implantation can be guided by intracavitary images. In principle, a balloon of the same diameter can be selected for high-pressure expansion. It is not recommended to exceed the edge of the stent during expansion.
5. Complications and treatment
(1) Coronary artery spasm:
(2) Coronary artery dissection and intramural hematoma:
(3) Branch occlusion:
(4) Coronary artery rupture or perforation:
(5) Balloon rupture or incarceration:
(6) No-reflow or slow blood flow:
Ⅱ. Semi-compliant balloon for coronary angioplasty
1. Overview
It is mainly used for pre-expansion of lesions before stent implantation, with a nominal pressure of 6-8 atm and a burst pressure of 14-16 atm. For every atm increase in filling pressure in the working range, the balloon diameter increases by about 8%-10%.
2. Device characteristics
Commonly used semi-compliant balloons have a diameter of 1.0-3.0mm and a length of 8-20mm.
3. Indications and contraindications
(1) Applicable situations:
① Pre-dilation of conventional lesions;
②Balloon dilatation for PTCA alone;
③ During the treatment of bifurcation lesions, cross the trabeculae of the stent and expand the mesh of the stent;
④ It is used for branch expansion when the kissing balloon is expanded in the treatment of bifurcation lesions;
⑤Used as an anchoring balloon; ⑥Used as a detention balloon.
(2) Situations where the effect is poor or not applicable:
① When the balloon cannot pass through the high resistance lesion;
② Pretreatment of severe calcified lesions.
4. Operating procedures and technical points
5. Complications and treatment
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