Percutaneous and Non-fluoroscopic Technique Basics: How and Who

Structural heart disease (SHD), an emerging speciality in cardiovascular medicine, encompasses structural abnormalities affecting cardiac valves, the myocardium and pericardium, as well as major vascular malformations. As a leading cause of global morbidity and mortality, SHD presents particular public health challenges in tropical and other low-resource settings. Advanced maternal age at first childbirth is associated with an elevated risk of cardiovascular disease during pregnancy. Gestation during late reproductive years (ages 40–50) correlates with a higher prevalence of cardiovascular risk factors.¹ This trend is exacerbated by demographic shifts toward delayed childbearing and population aging, which collectively drive an increase in the incidence of SHD. An increase in this complex patient population requires expanded access to safe and effective cardiovascular intervention therapies.²

Cardiovascular intervention therapy has undergone tremendous transformation over recent decades. Since 1929, when Forssmann performed self-catheterisation under X-ray guidance, catheter-based interventions have matured rapidly, surpassing traditional surgery in various fields and becoming the primary treatment modality for patients with SHD.^3-5 However, traditional fluoroscopy-guided intervention treatment faces three major challenges: iatrogenic injury, limited accessibility and limitations to the information provided in the images.^6-8

Radiation exposure can affect the function of human bone marrow, the kidneys and other organs.^9,10 Cancer risks have been reported to increase slowly with radiation doses <55 mSv, but to increase rapidly for doses above 55 mSv.¹¹ In addition, widely used contrast agents may cause allergic reactions, impaired renal function or even renal failure, limiting their use in patients with contrast allergy, renal insufficiency, pregnancy and immunosuppression.^12,13 For medical operators, accumulated radiation exposure can reach thousands of minutes annually, and long-term radiation exposure significantly increases tumour incidence.^14,15 To protect against radiation exposure, medical personnel must wear lead aprons weighing several kilograms, increasing the physical burden placed upon them and potentially causing cervical and lumbar spine injuries, severely affecting work efficiency and comfort.¹⁶

Traditional fluoroscopy-guided intervention equipment is expensive and requires specialised radiation protection facilities and dedicated technical teams, limiting its widespread application in primary hospitals and underdeveloped regions. X-Ray imaging provides uniplanar images, is unable to clearly show cardiac structures and blood flow and is only used for guidance during critical steps rather than continuous real-time monitoring.¹⁷

To overcome these challenges, the percutaneous and non-fluoroscopic (PAN) technique was developed. This concept was first proposed in 2007 by Xiangbin Pan’s team at Fuwai Hospital, Chinese Academy of Medical Sciences, who integrated multidisciplinary advantages to establish an ultrasound-guided percutaneous intervention system.¹⁸ Based on the principle of ‘capturing everyone’s excellence’, Pan et al. combined the advantages of non-invasiveness and precise positioning to pioneer a new cardiac treatment model without the need for scalpels, radiation or tracheal intubation.¹⁹ After more than a decade of exploration and clinical application, the PAN technique can now be safely and effectively used for percutaneous intervention treatment for atrial septal defect, patent foramen ovale, perimembranous ventricular septal defect (VSD), patent ductus arteriosus, pulmonary valve stenosis, aortic valve stenosis, mitral regurgitation, AF and coarctation of the aorta, with a success rate of 99% and no serious complications such as cardiac perforation, cardiac tamponade, valve injury or immediate occluder dislodgement.²⁰

However, implementation of the PAN technique still faces numerous challenges, primarily high technical difficulty and a steep learning curve. This primarily stems from fundamental differences between the working principles of ultrasound and fluoroscopy: fluoroscopy operates based on projection, whereas ultrasound examines 3D objects by scanning individual sections, making it difficult to clearly display the overall contour of catheters and guidewires. To address these issues, a series of specialised instruments and surgical techniques have been developed, significantly reducing the learning curve and enabling younger physicians to perform these techniques more quickly and safely.²⁰ This article details the implementation methods and indications for the PAN technique, providing cardiovascular interventionists with comprehensive, systematic technical guidance to promote the global application of this safe, effective and economical technology.

The Percutaneous and Non-fluoroscopic Technique

Definition

The PAN technique is a fluoroscopy-free, minimally invasive approach to diagnose and treat cardiovascular diseases (especially congenital and acquired SHDs) through peripheral vessels, using echocardiographic guidance and intervention tools. Unlike conventional approaches, the PAN technique allows patients to remain conscious without a thoracotomy or radiation exposure. By eliminating iatrogenic risks, the PAN technique not only enhances patient safety but also significantly improves healthcare accessibility.

Technical Fundamentals

The PAN technique revolutionises interventional cardiology by overcoming challenges from the heart’s dynamic anatomy. Unlike static organs, cardiac motion complicates catheter navigation, traditionally limiting ultrasound guidance. The PAN technique overcomes these limitations by integrating advanced echocardiography with specialised instrumentation for precise, radiation-free intervention in real time.

Echocardiography serves as the technological foundation, providing comprehensive cardiac assessment through real-time visualisation of cardiac anatomy, function and detailed haemodynamic evaluation.²¹ The echocardiogram includes M-mode echocardiography, 2D and 3D echocardiography and Doppler echocardiography, among others. In clinical practice, although transthoracic echocardiography (TTE) provides standard parasternal, apical, subxiphoid and suprasternal views, its imaging may be limited by patient anatomy. In contrast, transoesophageal echocardiography (TOE) delivers superior visualisation of key structures, including the atrial septum, left atrial appendage and valvular apparatus.

To overcome the limitations of traditional echocardiographic guidance, a novel 3D curved ultrasound-guided delivery system was developed, adapting to cardiac anatomy. Its rotational capability converts passive single-plane scanning into active 3D detection, improving the probability of echocardiography detection fivefold.²² In addition, an echocardiography-guided catheter featuring a large-cavity-and-thin-edge design creates metal–liquid–polyurethane interfaces, leveraging density variations to enhance signal reflection and boost decibel levels by 20–30%.¹⁸ Another advance is the adaptive guidewire (Panna™ wire, Hangzhou Dexin Medical Technological Company) with a spindle-shaped expandable tip that dynamically adjusts volume for optimal ultrasound detection. Combined with the effective echo view method, this integrated system significantly improves clinical outcomes, raising novice operators’ surgical success rates from 69% to 100% in randomised trials.¹⁹

The PAN procedure integrates innovative techniques to enhance the precision of intracardiac intervention. The key anatomical structure detection method uses stable vascular landmarks (e.g. entrance of the inferior vena cava, aortic isthmus) to establish fixed imaging planes. This enables reliable echocardiographic tracking of device tips, increasing positioning success rates from 50% to over 98%.¹⁹ Two additional methods further optimise safety: the working length marking method ensures controlled insertion depth, minimising sheath over-advancement and reducing the rate of complications from 6.5% to <0.2%, whereas the effective echo view method visualises device trajectories (>1 cm) for precise distal tip positioning.²² By synergising these echocardiographic advances with intervention tools, the PAN procedure overcomes the fundamental ‘find, locate, orient’ challenge, achieving unmatched accuracy in structural heart interventions and redefining standards in minimally invasive cardiology.

Echocardiography remains indispensable in intervention therapy, providing critical structural and functional assessment throughout treatment. Its preoperative use enables precise evaluation of the morphology and spatial relationships of cardiac defects, which is critical for patient selection and procedural planning beyond radiographic capabilities. Preoperative echocardiographic assessment of cardiac function, pulmonary artery pressure and other haemodynamic parameters enables accurate prediction of surgical risks and patient outcomes. The synergistic use of TTE during interventions significantly reduces radiation exposure while maintaining procedural precision. Although uncommon, postoperative complications such as pericardial effusion, device-related valve perforation and atrial wall injury can have serious clinical implications. Consequently, systematic echocardiographic follow-up during the postoperative period is an indispensable safety measure, ensuring the timely detection and management of potential complications. This comprehensive echocardiographic approach, which encompasses preoperative evaluation, intraprocedural guidance and postoperative surveillance, establishes an optimal safety framework for interventional cardiac procedures while minimising radiation hazards (Figure 1).

How to Perform the Percutaneous and Non-fluoroscopic Procedure

Preoperative Preparation and Planning

The PAN procedure, as a radiation- and contrast-free minimally invasive cardiac intervention, requires meticulous preoperative preparation and comprehensive planning for successful implementation. Detailed patient assessment, including cardiac lesion type, severity, location and surrounding anatomical relationships, is essential for appropriate device selection and determining the intervention approach. Echocardiography serves as the core preoperative evaluation tool, with TTE and TOE selected according to patient condition to ensure clear visualisation of lesion sites.

To ensure procedural safety, particularly for new centres, the PAN technique should be performed in surgical operating rooms, allowing immediate conversion to open heart surgery if emergency situations arise. Regarding team configuration, operators must have extensive experience in percutaneous interventions, proficiency in completing routine percutaneous interventions under fluoroscopic guidance and fundamental knowledge of ultrasound imaging.

Technical Workflow

The PAN technique follows a standardised three-step workflow. First, operators should establish vascular access under ultrasound guidance using puncture needles, selecting appropriate routes based on lesion type. For example, femoral vein access is typically preferred for closure of atrial septal defects, whereas femoral artery or jugular vein approaches may be chosen for VSD closure depending on the distance between the defect and the aortic valve. Second, the operator should use the working length marking method to measure the distance in vitro and mark it on the catheter and guidewire, confirming the precise in vivo catheter and guidewire insertion depth. Third, after confirming the location of the affected areas by using the effective echo view method, an occluder/stent/balloon/clip/heart valve can be released or implanted (Figure 1).

Management Strategies for Intraoperative Complications

Continuous monitoring of changes in patient vital signs and ultrasound images is crucial during the PAN technique, and medical staff should remain prepared to address emergency situations. In addition, back-up support equipment, including defibrillators, extracorporeal circulation machines, thoracotomy instruments and endotracheal intubation equipment, should be available to maximise patient safety.

Pitfalls in Early Adoption

Early application of the PAN technique was first reported by Fuwai Hospital, Chinese Academy of Medical Sciences, from February 2014 to March 2015, involving 42 select patients with perimembranous VSD who underwent purely ultrasound-guided VSD closure.²³ The procedure was successfully completed in 38 patients. Two patients required conversion to ultrasound-guided minithoracotomy closure due to an inability to advance the catheter along the guidewire through the VSD, whereas another two patients were converted to conventional surgical repair because of residual shunts exceeding 2 mm. Immediate post-procedure evaluation revealed trivial residual shunts in four patients, all of which resolved by the 1-month follow-up. Three patients developed new-onset right bundle branch block, with two recovering before discharge. At the 6-month follow-up, no complications such as pericardial effusion, device embolisation, atrioventricular block or haemolysis, were observed in any patient.²⁴

The purely ultrasound-guided transfemoral approach for perimembranous VSD closure demonstrates excellent safety and efficacy profiles, achieving comparable outcomes to fluoroscopy-guided procedures while eliminating radiation exposure and the use of a contrast agent. This technique offers distinct advantages in preventing valvular damage by obviating the need to establish a femoral artery–VSD–femoral vein rail.²⁵ However, compared with conventional intervention methods, fluoroscopy provides projective imaging that facilitates clear catheter localisation, whereas ultrasound’s tomographic approach often yields less precise positional information. Successful implementation requires operators experienced in conventional percutaneous interventions, preferably conducted in hybrid operating rooms to enable emergency conversion when necessary. Critical technical aspects include accurate catheter length marking measured from chest wall to vascular access site to prevent cardiac injury from over insertion and using recorded insertion depths during device exchanges to guide optimal sheath advancement. These patient-specific measurements account for anatomical variations, ensuring precise lesion targeting while avoiding complications from excessive device advancement or premature guidewire removal. Specialised equipment, such as ultrasound-compatible guidewires (Panna^TM wire) and preshaped catheters, further enhances outcomes in patients with complex anatomy, with careful patient selection and individualised procedural planning being paramount.²⁰

Although the technique demands operator expertise and entails a steep learning curve, it holds significant clinical potential when performed by properly trained teams following strict indications and standardised protocols.

Who Might Benefit from the Percutaneous and Non-fluoroscopic Procedure?

Indications

A systematic comparison of SHD indications between the PAN technique and conventional percutaneous interventions reveals distinct clinical advantages of the PAN procedure (Supplementary Table 1).^26-29 The eligibility criteria for the PAN technique are expanded through three principal dimensions: a broader patient age range, adjusted symptomatic thresholds, and the inclusion of specific demographic or clinical groups. The PAN technique overcomes traditional age restrictions by eliminating the 60-year upper age limit for patent foramen ovale closure in elderly patients while also enabling the treatment of younger paediatric patients with perimembranous VSDs, regardless of lower body weight.^30,31 In addition, the PAN technique covers a wider spectrum of clinical symptoms, such as in pulmonary valve stenosis, where it can be used in symptomatic patients (exertional dyspnoea, syncope or presyncope) with pressure gradients ≥30 mmHg (1 mmHg=0.133 kPa), compared with the conventional 40-mmHg threshold required by traditional percutaneous techniques.²⁰ Furthermore, the PAN technique can be used in people with aortic valve stenosis who were previously excluded from interventional procedures, such as competitive athletes, pregnant women and asymptomatic patients with risk factors, thereby affording greater flexibility in real-world clinical scenarios.³⁰

The PAN technique results in superior clinical benefits through two key innovations. First, its ultrasound-guided approach eliminates risks associated with radiation and the use of contrast, significantly improving safety for vulnerable populations like infants and pregnant women. Second, specialised instrumentation, including the Panna wire system and dedicated occluders, reduces complications, enabling broader therapeutic applications across diverse patient groups.

Clinical Significance

Radiation exposure presents substantial health hazards, particularly for vulnerable populations such as paediatric, obstetric, oncological and renally impaired patients.³² The US Food and Drug Administration’s 2015 safety alert highlighted 10 cases of infantile hypothyroidism following the administration of iodinated contrast media to neonates with congenital heart disease or prematurity.³³ A 2016 retrospective study cited an increased risk of stillbirth/neonatal death, as well as increased risk of rheumatological, inflammatory or infiltrative skin conditions in the offspring, after exposure to gadolinium-based contrast agents during pregnancy.³⁴ In 2023, CT scans performed in the US were projected to cause around 103,000 additional cancer cases.³⁵ If current trends continue, cancers linked to CT scans may eventually represent 5% of all new annual cancer diagnoses.³⁶ The WHO states that when the effective dose of ionising radiation exposure surpasses 100 mSv, the risk of cancer rises significantly.³⁷ For patients with chronic kidney disease (CKD), the risks extend to nephrogenic systemic fibrosis, with estimated incidence rates of 1–7% after exposure to gadolinium-based contrast agents in patients with advanced CKD (estimated glomerular filtration rate <30 ml/min/1.73 m²), particularly among those with end-stage renal disease (Stage 5 CKD) or severe impairment (Stage 4 CKD).^38-40 Conventional cardiac interventions inevitably entail radiation exposure, posing significant clinical challenges.

The PAN procedure tackles this therapeutic dilemma through its radiation-free platform, establishing itself as the intervention of choice for high-risk cohorts. Its clinical implementation has successfully bridged critical gaps in interventional cardiology, enabling definitive treatment for previously ineligible patients while maintaining optimal therapeutic outcomes. The methodology has demonstrated particular efficacy in mitral valve repair procedures, achieving comparable outcomes to conventional approaches while eliminating radiation-associated morbidity.⁴¹ Such advances position the PAN procedure not merely as an alternative but also as the emerging standard for high-risk cardiovascular interventions in the modern era. The PAN procedure enables medical staff to work without the burden of heavy lead shielding, reducing long-term radiation risks. This safer, more comfortable environment enhances clinical performance, allowing healthcare providers to optimise patient care and treatment efficacy.

Precise visualisation is fundamental to successful cardiac interventions. Conventional X-ray fluoroscopy provides only uniplanar projection imaging, which lacks the ability to display detailed cardiac anatomy or dynamic blood flow. Moreover, its guidance is intermittent and typically limited to critical procedural steps, rather than providing continuous monitoring. Sole reliance on X-ray guidance is comparable to navigating a complex route with only occasional visual references, which significantly increases procedural risks. Unlike alternative methods, echocardiography enables uninterrupted 3D imaging that clearly shows cardiac structures such as valves and chordae tendineae, along with dynamic blood flow patterns throughout the intervention. This continuous, high-resolution guidance significantly enhances procedural accuracy and safety, reducing complications and improving clinical outcomes.

The PAN procedure represents a transformative advance in cardiovascular care by delivering cost-effective treatment without the infrastructure demands of traditional cath labs (US$4.14–5.52 million), which typically require a minimum investment of US$0.15 million.⁴² This innovative approach circumvents the need for expensive cath lab facilities and specialised radiation equipment. By using mobile surgical units, the PAN procedure can be deployed across diverse clinical environments, from community hospitals to remote villages. These compact, vehicle-based operating theatres replace conventional radiation shielding with space-efficient designs and laminar airflow systems, enabling safe interventions in resource-constrained areas. The system directly addresses the global shortage of intervention specialists through its robotic-assisted platform, which facilitates precise remote operations, thereby extending specialist-level care across geographical barriers. Notably, the robotic system has demonstrated clinical efficacy by successfully performing transcatheter mitral valve edge-to-edge repairs at distances exceeding 2,500 km.⁴³ By combining robotics with mobile surgical technology, the PAN procedure not only breaks through workforce limitations but also enhances the efficiency of mobile units, allowing procedures to be conducted in standard clinical or outpatient settings without hospitalisation. This paradigm shift yields substantial healthcare economic benefits, significantly reducing capital and operational expenditures while maintaining therapeutic efficacy.

The PAN procedure provides substantial clinical advantages for treating diverse cardiovascular conditions, with proven effectiveness in managing heart valve diseases.^43–46 It also serves as an important therapeutic option for arrhythmias, particularly in treating AF and facilitating pacemaker implantation.^47–49 Beyond these applications, the PAN procedure is especially valuable for patients who cannot undergo traditional interventions due to contraindications involving radiation or contrast agents. This includes pregnant women, infants, young children, individuals with contrast allergies, renal insufficiency or those with cancer and immunosuppression, offering them a safer and more accessible treatment option.

Discussion

The PAN procedure represents a major breakthrough in interventional cardiology, combining enhanced imaging guidance with optimised catheter strategies to improve procedural safety and precision while eliminating radiation exposure. This innovative approach offers significant advantages over conventional fluoroscopy, including improved patient accessibility and cost-effectiveness, ushering in a new era of minimally invasive cardiovascular therapy.

However, the learning curve for operators transitioning from traditional methods is steep. For optimal training outcomes, a structured training pathway should be followed, beginning with simpler procedures such as atrial septal defect closures before progressing to more complex interventions. TOE is preferred for initial training due to its superior imaging quality, particularly for posterior cardiac structures, whereas TTE may be adequate for select patients with favourable anatomy. Ultimately, this graduated approach ensures both patient safety and the development of operator competency in this evolving field. With accumulated experience and refined operative skills, this approach promises broad application prospects in interventional cardiology.

The PAN procedure is an internationally acclaimed medical platform validated for safety, efficacy and accessibility, recognised by the WHO (Innovation Award) and China’s National Technological Invention Award.^50–52 Standardised via the IEEE and codified in two international standards and three guidelines, the system uses 23 specialised devices (12 CE-certified).^18,30,53,54 Over 10 years, the PAN techniques have been implemented in 68 countries across Europe, Asia and Africa, including France, Germany, Japan, Russia, Thailand and Kenya.⁵¹ Its clinical success across diverse healthcare settings has established it as a paradigm-shifting advance in interventional medicine. As part of the UN Sustainable Development Goals, the PAN procedure initiative has expanded access to cardiac care to underserved populations, supported by an international training program spanning over 30 countries.^22,50 The Beijing-based training program has certified 1,192 professionals from 32 countries, supported by 12 mobile surgical units for global deployment.²⁰ The technology has earned international acclaim, with WHO Director-General Margaret Chan, CSI Chairman Mario Carminati and PCR London Valve Chairman Francesco Maisano endorsing its clinical value.^50,55 The PAN procedure’s reproducible outcomes and ability to resolve critical unmet needs continue to drive its global adoption as a transformative medical innovation.

Conclusion

The PAN technique represents a significant innovation in cardiovascular intervention therapy, successfully overcoming the limitations of traditional fluoroscopy-guided methods. By eliminating the use of radiation and contrast agents, the PAN procedure substantially reduces iatrogenic injury risks while enhancing healthcare accessibility and affordability. Implementation relies on innovative positioning methods and specially designed devices, such as the key anatomical structure detection method and echo-guided wires, which significantly shorten learning curves and improve success rates. In conclusion, the PAN technique represents a technological revolution in cardiovascular intervention therapy, addressing the challenges that traditional techniques struggle to overcome through innovative methods. Guided by the principles of ‘protecting patients, protecting doctors, saving costs and suitable for promotion’, the PAN technique will continue to develop and benefit more patients globally, making a significant contribution to achieving the goal of heart health for all.

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