Forgot your password?
Management of Coronary Calcified Nodules
Ayman Helal, Cardiology MD
Interventional cardiologist, Kettering General Hospital, The UK
Introduction:
Coronary artery calcification is becoming increasingly prevalent and is linked to elevated rates of immediate procedural failure and adverse clinical consequences. Severe calcification stands out as a primary contributor to procedural PCI failure. It can impede device advancement, render stenosis resistant to dilation, or trigger PCI-related complications, including dissection, perforation, or mechanical problems with stents (such as under expansion, distortion, or loss) which collectively increase the procedural risk. The recent progress in both invasive and non-invasive coronary imaging methods can be integrated with the calcium modification techniques to facilitate targeted and precise approaches to percutaneous coronary intervention (PCI). [1]
Calcified nodules (CN) represent a major challenge in intervention due to their association with increased procedural complexity and risk of adverse events as the nodules are usually eccentric, hard, and difficult to treat. This article aims to provide a comprehensive review of the current strategies and techniques for the interventional management of calcified coronary nodules.
A calcified nodule is identified as a calcium mass exhibiting a convex structure within the vessel’s lumen, often accompanied by a heavily calcified plaque underneath. It may manifest as an eruptive lesion with disruption of the fibrous cap and the presence of luminal thrombus. It presents in 22-40% of patients undergoing plaque modification.[2] Presence of calcific nodules is associated with 3-fold risk of adverse events in observational studies. It can hinder the progress of devices, make stenosis non-dilatable, or provoke complications related to PCI, such as dissection, perforation, or mechanical issues with stents (such as stent under expansion, distortion, dislodgement, or loss). These complexities collectively elevate the procedural risk. [3]
Accurate assessment of CN is essential for planning optimal intervention strategies. Multimodal imaging techniques such as intravascular ultrasound (IVUS), optical coherence tomography (OCT), and coronary computed tomography angiography (CCTA) play crucial roles in characterizing the extent, distribution, and morphology of calcified lesions. SCAI Expert Consensus (2024) recommend using intracoronary imaging to identify CN in relation to overall calcium distribution, assess guide wire bias, and provide reference vessel size to assist in calcium modification device selection. [4]
2.1 IVUS assessment:
IVUS-detected CN were categorized into 5 types based on the IVUS observations (Figure 1). Type 1 denoted an eccentric calcified nodule lacking superficial calcification on the opposite side. Type 2 denoted an eccentric calcified nodule with extensive (≥180˚ arc) superficial calcification on the opposite side. Type 3 denoted an eccentric calcified nodule with a narrow (<180˚ arc) pattern of superficial calcification on the opposite side. Type 4 indicated multiple CN within the lumen. Type 5 represented a calcified nodule accompanied by visible luminal thrombus. The most dominant type of IVUS-CN is eccentric calcified nodule without calcification at the opposite site of the calcified nodule (Type 1). Normal vessel structure at the opposite site of the IVUS-calcified nodule usually allow adequate stent expansion. [5]
Figure 1: The classification of IVUS-CN: Upper panels show the schemes of CN, and lower panels show the corresponding IVUS images. Black represents calcification, yellow represents non-calcified plaques, orange represents visible thrombus, white represents vessel lumen, and red represents vessel wall.
2.2 OCT assessment:
Calcific nodules were identified in 5-6% of patients dying of acute coronary syndromes (ACS). Such findings have been corroborated in recent years through optical coherence tomography (OCT) studies. OCT precisely identifies calcific nodules and discerns between calcified nodule with (CND) or without (CNWD) disruption of the intimal fibrous layer (Figure 2). A sub analysis of CLIMA study, which was a large prospective registry on plaque vulnerability assessed by means of OCT, concluded that the presence of CND was associated with a high one-year incidence of cardiac death and/or target lesion MI. [6]
Figure 2: Calcified nodule without “CNWD” fibrous layer disruption (arrow in the left panel) and with (CND) fibrous layer disruption plus thrombus “arrow in right panel”.
2.3 Computed tomography coronary angiography (CTCA) assessment:
CTCA is a good non-invasive tool to assess coronary plaque morphology based on CT values into low-attenuation, fibrous, and calcified plaques, allowing for quantitative analysis of plaque volumes. In a recent study, CTCA is useful for predicting OCT-detected CNs in PCI target vessels, and quantitative measurements of the calcium burden in coronary vessels can help to identify the presence of CNs (Figure 3). [7]
Figure 3: Representative CTCA and OCT images of calcified plaques.
Interventional cardiologists may occasionally opt not to utilize calcium modification techniques in cases involving CN. Nevertheless, all the calcium modification techniques can be used.
3.1 Intravascular Lithotripsy (IVL)
A recent analysis highlighted the role of Intravascular Lithotripsy (IVL) in addressing differential stent expansion parameters for lesions with and without CNs. The analysis revealed that IVL effectively closed the gap in stent expansion parameters between these two lesion types. This finding underscores the efficacy of IVL in optimizing stent deployment and ensuring uniform expansion across both calcified and non-calcified lesions, ultimately contributing to improved procedural outcomes. This provides valuable insights into the safety and effectiveness of IVL for the treatment of CN in coronary artery disease. [10]
SCAI (Society for Cardiovascular Angiography & Interventions) Expert Consensus (2024) recommend that IVL sizing in CN should be 1:1 with the reference vessel diameter, and more pulses are often required to modify CN vs non-CN lesions. Then to perform NC 1:1 balloon dilatation prior to stenting, ideally followed by imaging to confirm the presence of calcium fracture [4]
3.2 Rotational atherectomy (RA)
The effectiveness of rotational atherectomy in managing CN remains uncertain. Watanabe et al. found no disparity in terms of 1-year ischemia-driven target vessel revascularization (TVR) in patients treated with RA compared to a matched group treated without RA, as detected by IVUS. However, this study was constrained by the relatively small sample size, with 42 patients in each group. [5] In another investigation, Morofuji et al. examined the impact of CN on the outcomes of patients undergoing RA. Their analysis revealed that patients with CN (128 patients) exhibited a higher incidence of 5-year clinically driven target lesion revascularization (TLR) and stent thrombosis compared to patients without CN (136 patients). [8]
To optimize stent outcomes, more aggressive lesion preparation techniques such as RA combined with orbital atherectomy or RA with cutting balloon or intravascular lithotripsy might be necessary. Nonetheless, due to the unstable characteristics and varying degrees of hardness of CN, there is a risk of distal embolization following RA. [9]
SCAI Expert Consensus (2024) recommend upsizing the RA burr-to-artery ratio to 0.6 or 0.7 in CN if the lumen is large and there is unfavourable guide wire bias or consider using the RotaWire Extra Support to change the guide wire bias, as needed. Then to perform NC 1:1 balloon dilatation prior to stenting, ideally followed by imaging to confirm the presence of calcium fracture [4]
3.3 Orbital atherectomy (OA)
Orbital atherectomy has emerged as a valuable tool in the management of calcified coronary lesions, including CN, offering a means to modify and debulk calcified plaque to facilitate successful stent deployment and optimize clinical outcomes. This was published in several case reports; however, up to this point there is no randomized controlled trial to investigate its outcome.
SCAI Expert Consensus (2024) recommend slow OA device motion (1 mm/s), a high number of passes (>5), and higher speed (120,000 rpm) in CN. Then to perform NC 1:1 balloon dilatation prior to stenting, ideally followed by imaging to confirm the presence of calcium fracture [4]
3.4 Future prospective for Calcium modification technique of choice:
The ROLLERCOASTR trial presents a promising avenue for advancing the management of calcified coronary stenosis by comparing the efficacy and safety of rotational atherectomy (RA), intravascular lithotripsy (IVL), and laser atherectomy. It has the potential to inform evidence-based decision-making and guide personalized treatment strategies for patients with calcified coronary stenosis in general and CN in particular. [11]
Despite advances in interventional techniques, the management of complications associated with calcified coronary nodules remains challenging. Strategies for addressing complications such as coronary perforation, distal embolization, and no-reflow phenomenon include the use of covered stents, embolic protection devices, vasodilators, and adjunctive .
Several studies have demonstrated favourable outcomes following intervention for calcified coronary arteries, including improved myocardial perfusion, reduced rates of major adverse cardiovascular events, and enhanced long-term survival [5]. However, the optimal treatment strategy should be individualized based on patient-specific factors, lesion characteristics, and operator experience.
Conclusion:
Interventional management of calcified coronary nodules requires a multidisciplinary approach and utilization of advanced technologies to achieve optimal procedural success and improve clinical outcomes.
References: