Advances in catheter based physical treatments
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Alberto Castro Molina, M.D.
Overview
Advances in catheter based physical treatments
Interventional procedures have been plagued by restenosis due to the formation of endothelial tissue overgrowth at the lesion site. Restenosis is the body's response to the injury of the vessel wall from angioplasty and to the stent as a foreign body. As assessed in clinical trials during the late 1980 and 1990s, using only balloon angioplasty (POBA, plain old balloon angioplasty), up to 50% of patients suffered significant restenosis but that percentage has dropped to the single to lower two digit range with the introduction of drug-eluting stents. Sirolimus and paclitaxel are the two drugs used in coatings which are currently FDA approved in the United States. As opposed to bare metal, drug eluting stents are covered with a medicine that is slowly dispersed with the goal of suppressing the restenosis reaction.
The key to the success of drug coating has been;
- choosing effective agents,
- developing ways of adequately binding the drugs to the stainless surface of the stent struts (the coating must stay bound despite marked handling and stent deformation stresses) and
- developing coating controlled release mechanisms that release the drug slowly over about 30 days.
Contemporary role of catheter based revascularization
In patients with chronic coronary disease (CCD) and lifestyle limiting angina despite guideline-directed medical therapy (GDMT), coronary revascularization is recommended to improve symptoms.[1] In selected patients with multivessel coronary artery disease (CAD) appropriate for either coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI), revascularization in addition to GDMT is reasonable to reduce spontaneous myocardial infarction, unplanned urgent revascularization, or cardiac death.[1]
Physiologic lesion assessment before PCI
In patients with CCD who have angina or an anginal equivalent, no previous evaluation for ischemia, and angiographically intermediate stenoses, physiologic lesion assessment with fractional flow reserve (FFR) or other proven nonhyperemic pressure ratios such as instantaneous wave-free ratio (iFR) is recommended before proceeding with PCI.[1] FFR guided PCI is also considered a high economic value intervention in patients undergoing coronary angiography without prior stress testing.[1]
Patient selection and Heart Team decision making
Selection of PCI should be individualized according to anatomic complexity, comorbidities, surgical risk, and patient goals.[1] In patients with CCD with complex 3 vessel disease or when the optimal treatment strategy is unclear, a Heart Team approach that includes interventional cardiology and cardiac surgery is recommended to improve patient outcomes.[1] CABG is generally preferred over PCI in patients with significant left main involvement associated with high complexity CAD, in patients with diffuse or complex multivessel CAD such as a SYNTAX score >33, and in many patients with diabetes and multivessel CAD who are suitable surgical candidates.[1]
Imaging and follow up after prior catheter based treatment
In patients with CCD and a change in symptoms or functional capacity that persists despite GDMT and who have undergone previous coronary revascularization, coronary computed tomography angiography (CCTA) is reasonable to evaluate bypass graft or stent patency when the stent diameter is 3 mm or greater.[1] Routine periodic anatomic or ischemic testing is not recommended in asymptomatic patients without a change in clinical or functional status.[1] Routine follow up invasive coronary angiography in asymptomatic patients may increase repeat revascularization of nonischemic lesions without improving subsequent rates of cardiac death or myocardial infarction.[1]
Symptom relief and limitations of invasive management
The principal benefit of PCI in stable CCD is relief of angina and improvement in quality of life, with the greatest benefit observed in patients who have more frequent angina at baseline.[1] In asymptomatic patients, routine invasive management has not been shown to improve major adverse cardiovascular outcomes compared with conservative care.[1]
Other physical therapies for no option refractory angina
In patients with CCD, refractory angina, and no other treatment options, enhanced external counterpulsation may be considered for relief of symptoms.[1] Contemporary guideline review does not support a recommendation for direct percutaneous transmyocardial laser revascularization because sham controlled evidence failed to show benefit and suggested possible harm.[1]
Drug coated balloon angioplasty
Drug coated balloons (DCBs) are catheter based balloons coated with an antiproliferative drug, mainly paclitaxel or sirolimus, that is transferred to the vessel wall during balloon inflation to inhibit neointimal hyperplasia.[2] DCB angioplasty has emerged as a contemporary catheter based physical treatment because it avoids the implantation of an additional metal scaffold while still providing local drug delivery.[2]
Potential advantages of drug coated balloons
Potential advantages of DCBs over drug eluting stents include preservation of epicardial vasoreactivity, avoidance of an additional permanent metallic layer, avoidance of late stent thrombosis related to metal or polymer, facilitation of future surgical revascularization, faster reendothelialization, and the possibility of shorter dual antiplatelet therapy.[2] These characteristics make DCBs particularly attractive in selected lesions such as in-stent restenosis, small vessel disease, diffuse coronary disease, bifurcation lesions, and in some patients with high bleeding risk.[2]
Lesion preparation for drug coated balloon treatment
Adequate lesion preparation is pivotal for successful DCB use.[2] Predilatation is generally performed with semi compliant or noncompliant balloons using a 1:1 balloon to vessel ratio, with the goal of creating intimal disruption that facilitates drug transfer.[2] In heavily calcified lesions, additional plaque modification may be required with high pressure balloons, cutting balloons, scoring balloons, atherectomy, or intravascular lithotripsy.[2] A satisfactory result before DCB use includes residual stenosis less than 30%, TIMI 3 flow, a 1:1 balloon to vessel ratio, and absence of flow limiting dissection, while non flow limiting type A or B dissection is generally acceptable.[2]
Drug coated balloon technology
Current coronary DCB platforms use either paclitaxel or sirolimus.[2] Paclitaxel remains the most extensively studied drug for DCBs because of its rapid tissue uptake and prolonged retention in the vessel wall, whereas sirolimus coated balloons have been developed to exploit the favorable safety profile of limus based therapy despite slower tissue transfer and shorter retention.[2] Because balloons differ in drug, dose, excipient, release kinetics, and tissue persistence, a class effect should not be assumed across all DCB technologies.[2]
Paclitaxel and sirolimus coated balloons
Paclitaxel coated balloons are cytotoxic, have rapid tissue absorption and long tissue retention, and remain the most clinically validated DCB platform.[2] Sirolimus coated balloons are cytostatic, have slower tissue uptake and shorter tissue retention, and have required dedicated delivery technologies such as nanoparticle carriers or microreservoir polymer systems to improve vessel wall retention.[2] Commercially available DCBs include several paclitaxel based platforms and newer sirolimus based devices such as Selution, Magic Touch, SeQuent Please SCB, and Mozec SEB.[2]
In stent restenosis
The best established use of DCBs is the treatment of in-stent restenosis (ISR).[2] In this setting, DCB therapy has shown superiority over plain balloon angioplasty and favorable angiographic and clinical outcomes compared with several stent based strategies, while avoiding placement of an additional stent layer.[2] BMS ISR and DES ISR represent different pathophysiologic entities, with BMS ISR more often related to diffuse neointimal hyperplasia and DES ISR more often associated with focal neoatherosclerosis.[2] Repeat DES implantation may still provide somewhat better angiographic lumen gain in some comparisons, but DCBs remain an important option because they treat ISR without creating further metal layers.[2]
Small vessel disease
DCBs have shown particular promise in de novo small vessel disease, where late lumen loss occupies a larger proportion of total vessel diameter after stent implantation.[2] Contemporary randomized data summarized in the review support DCBs as an effective and safe alternative to DES in selected small vessel lesions when lesion preparation is meticulous.[2] In addition, some studies reported lower rates of vessel or stent thrombosis and less serious bleeding with DCB strategies compared with DES, with a more pronounced benefit in patients with diabetes mellitus.[2]
Large vessel and diffuse coronary disease
The role of DCBs in de novo large vessel disease is evolving.[2] Potential advantages include avoidance of stent underexpansion or malapposition, especially in calcified segments or lesions requiring long treatment lengths.[2] For diffuse coronary disease, hybrid strategies using DES proximally and DCB distally have been proposed to reduce total stent burden, limit overlap, and avoid a full metal jacket, while observational data suggest similar midterm outcomes compared with DES only treatment in selected patients.[2]
Bifurcation lesions
In coronary bifurcation lesions, DCB therapy may be particularly useful for the side branch because it preserves the native bifurcation geometry and provides antiproliferative drug delivery without leaving an additional scaffold in the side branch.[2] Studies summarized in the review reported reductions in late lumen loss and restenosis compared with plain balloon angioplasty in side branch treatment, although routine use in de novo bifurcation lesions is still not universally recommended because comparative evidence versus DES remains limited.[2]
Chronic total occlusions
DCBs may also have a role in selected chronic total occlusion interventions, especially when full stent expansion is uncertain or when minimizing stent length is desirable.[2] Preliminary studies suggest feasibility, low restenosis rates, and the potential value of hybrid approaches combining DES and DCB to reduce the overall metallic burden while preserving scaffolding where needed.[2]
Acute coronary syndromes and high bleeding risk
Use of DCBs in selected acute coronary syndrome presentations has been explored, but current evidence remains limited and caution is advised, particularly in lesions with significant angiographic thrombus because thrombus may impair drug delivery to the vessel wall.[2] In patients with high bleeding risk, DCB treatment is attractive because it may allow shorter durations of dual antiplatelet therapy after PCI.[2] Consensus statements cited in the review support 1 month of dual antiplatelet therapy after elective PCI with a DCB only strategy in appropriate cases.[2]
Technical limitations
DCBs are generally less deliverable than standard balloons because of a larger crossing profile.[2] Delivery may be difficult in very tortuous, severely calcified, or distal lesions.[2] Careful handling is required to minimize drug loss during device delivery, and the balloon should generally extend beyond the lesion margins to optimize drug transfer to the entire treated segment.[2]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 Virani SS, Newby LK, Arnold SV et al. (2023). "2023 AHA/ACC/ACCP/ASPC/NLA/PCNA guideline for the management of patients with chronic coronary disease: a report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines". J Am Coll Cardiol. 82 (9): 833–955. doi:10.1016/j.jacc.2023.04.003.
- ↑ 2.00 2.01 2.02 2.03 2.04 2.05 2.06 2.07 2.08 2.09 2.10 2.11 2.12 2.13 2.14 2.15 2.16 2.17 2.18 2.19 2.20 2.21 2.22 2.23 2.24 2.25 2.26 2.27 2.28 2.29 2.30 2.31 2.32 2.33 Verde N, Ciliberti G, Pittorino L et al. (2024). "Contemporary Use of Drug-Coated Balloons for Coronary Angioplasty: A Comprehensive Review". J Clin Med. 13 (20): 6243. doi:10.3390/jcm13206243.