Risk factors associated with calcification:
- Diabetes mellitus
- Renal disease
- Parathyroid hormone abnormalities
Computed tomography coronary angiography
The key noninvasive technique for the identification of calcified lesions is computed tomography coronary angiography (CTCA). Coronary artery calcium scoring (CACS) is commonly used to measure coronary artery calcium (CAC) in CTCA. Research is suggestive of CAC having a favourable association with ECG and atherosclerosis. Most importantly, in reclassifying people with an intermediate risk of CAD (coronary artery disease), CACS plays an important role. The CACS calculation is important as most cardiovascular events occur in people with intermediate-risk, and intervention is best known for high-risk individuals to minimize risk than for those with intermediate-risk.
There are various strategies like balloon angioplasty, cutting balloon, rotational atherectomy, stenting, and laser for the treatment of coronary calcified lesions. However, it can get complicated due to vessel dissection, perforation, and vessel occlusion.
Balloon-based techniques do not extract calcium, but seek to increase the elasticity of the plaque and enable stent expansion in one or several areas by cracking calcified zones. Standard calcified lesion balloon dilatation also results in non-uniform balloon expansion and consequent overexpansion of more compliant vessel segments and injury to them. The newer non-compliant OPN balloon allows uniform expansion up to 40 atm of super-high pressures.
A diamond-coated elliptical burr is used in rotational atherectomy (RA) to rotate concentrically when progressing in a forward direction. Differential cutting enables the non-elastic, fibrocalcific plaque to be mechanically ablated while sparing adjacent compliant elastic vessel tissue. Calcium eccentricity, luminal region, burr scale, and degree of guidewire bias depend on the effect of RA on severely calcified lesions.
Intravascular lithotripsy (IVL) system is a novel balloon catheter-based device that utilizes pulsatile mechanical energy for disrupting calcified lesions. Miniature emitters turn electrical energy into transient acoustic circumferential pressure, which pulses along the length of a semi-compliant balloon that disrupts both superficial and deep calcium within the vascular plaque. Usually, the balloon is sized 1:1 to the diameter of the reference vessel, and inflated with subnormal pressures to allow contact with the vessel wall while reducing static barotrauma. IVL changes calcium, both circumferentially and transmurally, in a particular way and has a preferential impact on deep calcium, relative to other techniques of ablation.
Cutting and Scoring Balloons
Cutting and scoring balloons do not remove calcium in the coronary artery. However, they enhance vessel enforcement by making distinct incisions in the atherosclerotic plaque, allowing greater lesion expansion and reducing recoil while preventing uncontrolled dissections. In lesions with mild to moderate CAC, the cutting and scoring balloon scan should be done. The sign for the cutting balloon is that the lesion is relatively short.
Coronary artery bypass graft surgery
In patients with Class III to IV CAC based on intravascular ultrasound, coronary artery bypass (CABG)/open heart surgery is recommended, as is the expected difficulty in performing PCI, including the following characteristics:
The most accurate diagnostic technique for detecting coronary calcium with high tissue penetration is intravascular ultrasound (IVUS). IVUS, however, shows the calcified arc without determining its thickness due to acoustic shadowing. Despite more limited depth penetration, optical coherence tomography, with the higher spatial resolution, offers more accurate quantification of calcific plaque such as calcium area, thickness, length and 3D volume. This provides a better predictive response to the balloon dilatation.
Optical Coherence Tomography
To recognize CAC, optical coherence tomography (OCT) has high sensitivity and specificity. In addition, because light penetrates through calcium, optical coherence tomography can be used to measure the thickness and volume of calcification.