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Updated: August 17, 2022 5:12 p.m. STI

New Delhi [India]August 17 (ANI/ATK): As India celebrates 75 years of independence with Azadi ka Mahotsav, the field of interventional cardiology since its inception by Adreas Gruntzig in 1977, can it celebrate the absence of restenosis in-stent (ISR)?
SRI can be considered the “Achilles’ heel” of modern percutaneous coronary interventions (PCI).

Restenosis: Restenosis is a progressive narrowing of the stented segment that mainly occurs between 3 and 12 months after stent placement. The rate of in-stent restenosis decreased significantly with ISR rates of 30.1%, 14.6%, and 12.2% for BMS, first-generation DES, and second-generation DES, respectively.ISR still occurs in about 3 to 10 percent of patients within six to nine months.
Factors associated with in-stent restenosis (ISR)
We have learned that restenosis is a very complex process. Thanks to advances in technology, heart science is able to achieve a very low rate of restenosis.
Imaging technology-IVUS: intravascular ultrasound and OCT: optical coherence tomography
This imaging technique aids in proper characterization of lesions, assessment of vessel diameters and stent apposition, all of which aid in optimizing PCI, resulting in long-term low rate of SRI. Intracoronary imaging is playing an increasing role in guiding and optimizing PCI, especially as PCI in more complex and high-risk subsets. Imaging should be used before, during, and after stent deployment to get the most benefit from the use of imaging as it has an important role to play in all stages of an ICP procedure.
Stent Technology: Stents graduated from bare metal stents, first-generation drug-eluting stents (DES), second-generation DES, ultra-thin spacers, and third-generation DES, especially biodegradable polymers, polymer-free stents and biodegradable stents based on poly-L-lactide (PLLA) or magnesium. With improvements in stent design and technology, there is a gradual decrease in the rate of in-stent restenosis from 30% to nearly 3% with the current generation of DES.
Polymer-free stent: Currently, A9 biolimus-eluting stents without polymer or with biodegradable polymer sirolimus-eluting stent or polymer-free sirolimus and probucol-eluting stents are currently in clinical use. In clinical trials, these polymer-free stents have shown non-inferiority or numerically better results than stable polymer-based stents. Ten-year clinical results of a next-generation drug-eluting stent without polymer versus a durable polymer in patients with coronary artery disease with and without diabetes mellitus intracoronary stent outcomes and angiographic outcomes: sirolimus test efficacy – and probucol- and zotarolimus- The Eluting Stents trial (ISAR-TEST 5) showed comparable clinical results.
Bioresorbable Stent: Bioresorbable scaffolds (BRS) represent the fourth evolution of myocardial revascularization therapies with considerable technological development and advancements. This stent is made of a metal that safely dissolves automatically in the body two to three years after implantation and the patient’s artery returns to its normal position. The main metals in this category are magnesium-based and iron-based alloys, although recently zinc has also been studied.

Rotablation and intravascular lithotripsy (shock wave therapy)
For calcified lesions, rotablation has been in place for a long time, but the recent addition of user-friendly IVLs has provided more arsenals to the interventional cardiologist’s arsenal.
Intravascular shock wave lithotripsy (IVL) is a new device used in patients with calcified blockages. The Shockwave Medical Coronary IVL Catheter is a single-use, disposable catheter that is connected to an integrated balloon and equipped with multiple lithotripsy machines. This machine creates a sonic pressure wave for the affected area. This sonic pressure wave breaks down the calcium, creating space in the artery.
The popularity of IVL has increased due to a friendlier and shorter learning curve.
Plaque Modification-Cutting/Scoring Balloon and Open -NC- With the advent of these balloons, fibrocalcic lesions can be properly treated. This leads to proper preparation of the vascular bed which results in better clinical outcomes.
Balloons to cut out/mark
Cutting balloons consist of standard balloon catheters mounted with lateral metal blades which, upon inflation of the balloon, incise the treated stenotic plaque. Scoring balloons have a broadly similar mechanistic basis but use low profile nitinol wires (on the order of 125 µm) on the surface of the balloon catheter in a spiral formation.
OPEN -NC Balloon – OPN NC is a unique, Swiss-made, CE-marked plaque modification device designed to work in all complex lesions at ultra-high pressures. OPN NC uses ultra-high pressures to induce calcium fracture or oppose calcium to the arterial wall. OPN NC is engineered with dual-layer technology to withstand ultra-high pressures which leads to uniform expansion even at pressures as high as 45 bar.
Metabolic and Lifestyle Factors – Aggressive cholesterol control, better diabetes management, and healthy lifestyle measures are other factors that can prevent RSI. Lifestyle measures such as not smoking, maintaining an ideal body weight, daily physical activity and a healthy balanced diet. Aim for good physical health and a stress-free mind.
Appropriate use of these technologies in properly selected patients can result in a very low in-stent restenosis (ISR) rate and very low future clinical events. Achieving near-zero ISR is a dream of every cardiologist and a requirement for every patient and with further developments in cardiac technology, that day is not far off. Believe me, the conglomeration of lifestyle changes with good ICP optimization can work wonders.
This article is written by Dr (Prof). Tarun Kumar, MD, DM, FSCAI, FACC, Professor of Cardiology, ABVIMS & DR RML Hospital, New Delhi.
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