A new case series published in Frontiers in Cardiovascular Medicine on 15 October 2026 documents this danger in three men with repaired tetralogy of Fallot, all considered candidates for PPVI with self-expandable valves. The report, led by Rujira Buntharikpornpun and Supaporn Roymanee of Prince of Songkla University in Thailand, together with Worakan Promphan of Queen Sirikit National Institute of Child Health in Bangkok and Phuoc Duong of Alder Hey Children’s Hospital in Liverpool, shows how meticulous multimodal imaging can expose the risk before it strikes, and how, in two of the three cases, careful planning converted a high-risk situation into a successful implantation.

Coronary artery compression is uncommon but serious. With balloon-expandable valve platforms, the complication has been reported in roughly 5 to 10 percent of PPVI cases. Self-expandable valves, which exert less radial force on the surrounding tissue, are generally believed to carry a lower risk, and many published cohorts have reported zero instances of coronary compression or myocardial infarction. The new report challenges the assumption that this safety margin can be taken for granted. In all three patients, invasive testing during the procedure revealed evidence of coronary compression when the outflow tract was temporarily occluded with a balloon, even though two of the three ultimately received a valve without harm.

The first patient, a 20-year-old man evaluated 13 years after his original repair, illustrates how unusual coronary anatomy can turn a routine valve implantation into a hazard. Cardiac computed tomography revealed a single coronary artery arising from the left posterior-facing sinus, giving rise to the left circumflex, the left anterior descending artery, and two separate branches of the right coronary system. One of those branches followed a retropulmonary course, looping in front of the main pulmonary artery trunk along the valve annular groove before heading toward the right ventricular free wall. The distance between the planned valve landing zone and the nearest coronary artery measured just 1.5 millimeters.

During balloon sizing, the team inflated a 30-millimeter compliant balloon inside the outflow tract while simultaneously injecting contrast into the coronary arteries. At a waist diameter of 21 to 23 millimeters, the right coronary branch was visibly compressed against the expanding balloon. Because the outflow tract measured 25 to 26 millimeters on pre-procedural imaging but only 21 to 23 millimeters on balloon testing, implanting a valve large enough to anchor securely would have required significant oversizing, and no alternative landing position was feasible because the left anterior descending artery lay close to the supra-annular region. The team abandoned the procedure, sparing the patient a potentially catastrophic event.

The second patient, a 21-year-old man, presented a different anatomical puzzle. Computed tomography showed a single coronary artery system from which both the left and right coronary arteries arose, with the entire right coronary artery coursing anomalously in front of the outflow tract, closest to the pulmonary valve annulus. The clearance between the landing zone and the coronary artery was 2.7 millimeters. Balloon interrogation with a 34-millimeter Amplatzer sizing balloon demonstrated reduced flow to the distal right coronary artery at full inflation, with waist diameters of 28.9 and 29.3 millimeters in two planes.

Here, the deciding factor was dimensional distensibility. The valve annular measurement during balloon testing matched the pre-procedural computed tomography almost exactly, suggesting the tissue at that level was relatively non-compliant and would hold a valve without requiring oversizing. The team selected a 28 to 25 millimeter VenusP valve, delivered through a 26 French Gore Dryseal sheath that could double as a retriever in case of emergency. Post-implantation angiography showed normal flow to the distal right coronary artery. Follow-up computed tomography at three months confirmed the valve had conformed to roughly half of the original annular perimeter where the coronary crossed over, with uniform caliber and good distal perfusion. The patient remained asymptomatic, and cardiac magnetic resonance at three years showed no evidence of coronary compression.

The third patient, a 39-year-old man with severe pulmonary regurgitation, added yet another layer of complexity. His original repair had used a transannular patch extending into the main pulmonary artery, with significant calcification occupying up to a quarter of the perimeter at the valvar level. The main pulmonary artery was folded at nearly a right angle to the outflow tract, and the aortic root was dilated with clockwise-rotated coronary ostia. Computed tomography identified the distal main pulmonary artery in close contact with the left main coronary artery, just 2 millimeters from the landing zone. Balloon testing confirmed reduced flow to the left coronary artery at a waist of 24 by 25 millimeters, matching the computed tomography measurement of 25 by 25 millimeters.

Before the procedure, the team had also turned to three-dimensional printing. Using the patient’s computed tomography data, HARN Engineering Solutions fabricated a rigid model in acrylonitrile butadiene styrene, allowing the team to physically place a VenusP valve in both annular and supra-annular positions. The model showed that a supra-annular position would keep the valve’s distal flare much farther from the coronary artery than an annular position, supporting the geometrical assessment, though it could not predict the actual mechanical risk of compression. The team proceeded with a supra-annular placement of a 30 to 25 millimeter valve, avoiding oversizing and preserving future access to the left pulmonary artery for stenting. No ischemic electrocardiographic changes or ventricular dysrhythmias occurred during the procedure, and follow-up imaging at two months and again at three years showed unobstructed coronary flow.

Beyond the individual stories, the case series carries a broader technical message. Prior studies have proposed imaging thresholds for predicting coronary compression, including a coronary-to-landing-zone distance under 2 millimeters, a landing-zone-to-chest-wall distance under 8 millimeters, and the presence of anomalous coronary arteries. In all three patients reported here, the coronary distance fell below 3 millimeters while the chest wall distance exceeded 8 millimeters, yet the outcomes diverged based on tissue compliance and valve positioning rather than distance alone. The authors argue that patients showing coronary compression during balloon interrogation should not be automatically excluded from PPVI if the landing zone has a distinct fixed waist allowing non-oversized valve selection, if a supra-annular position is anatomically viable, and if alternative valve designs can avoid vulnerable compression zones. These preliminary hypotheses, the team acknowledges, will need validation in larger studies, but they suggest that the safety margins established for balloon-expandable valves in surgical conduits may not transfer directly to self-expandable devices in native outflow tract anatomy. Coronary artery compression, the report concludes, remains a persistent concern regardless of normal or abnormal coronary patterns, and vigilant multimodal imaging evaluation combined with operator awareness plays a pivotal role in identifying high-risk patients and preventing these complications proactively.

Subject of Research: Coronary artery compression in percutaneous pulmonary valve implantation: a case series

Article Title: Coronary artery compression in percutaneous pulmonary valve implantation: a case series

Article References: Buntharikpornpun, R., Roymanee, S., Promphan, W., & Duong, P. (2026). Coronary artery compression in percutaneous pulmonary valve implantation: a case series. Frontiers in Cardiovascular Medicine, 13, Article 1917017. https://doi.org/10.3389/fcvm.2026.1917017

Image Credits: AI Generated

DOI: 10.3389/fcvm.2026.1917017

Keywords: Coronary, artery, compression, percutaneous, pulmonary, valve, implantation, case, series, scientific research

The research, led by Belarmino Gonçalves of the Portuguese Oncology Institute of Porto and Thiago Franchi Nunes of Interventix in Campo Grande, Brazil, brought together ten tertiary referral centers across South America and Europe. Between January 2018 and July 2025, the investigators analyzed 68 diagnostic percutaneous transhepatic cholangioscopy, or PTCS, procedures performed in patients whose cross-sectional imaging and prior endoscopic evaluation had been nondiagnostic, or whose anatomy made standard endoscopic access impossible. Crucially, cases performed primarily to treat gallstones were excluded, isolating a cohort in which the sole purpose of the camera voyage into the ducts was to determine whether cancer was present.

The technique itself is a remarkable feat of interventional radiology. Using ultrasound and fluoroscopic guidance, physicians thread a needle through the liver into the bile ducts and establish a percutaneous tract, typically secured with a 10 to 12 French introducer sheath. Through that sheath, flexible cholangioscopes, single-operator platforms, or single-use ultra-slim endoscopes measuring roughly 2.8 to 3.5 millimeters in outer diameter are advanced directly into the biliary tree. Saline irrigation clears the field, allowing the operator to inspect the duct lining in real time — something computed tomography and magnetic resonance cholangiopancreatography fundamentally cannot do, since they offer only indirect views of the biliary mucosa. Some centers perform the cholangioscopic inspection in the same session when tract and sheath conditions permit; others prefer a staged approach roughly 48 to 72 hours later to allow decompression and reduce infection risk in patients with cholangitis or complex anatomy.

During each procedure, operators recorded two kinds of optical judgments before any tissue results were known. The first was a global impression — a binary real-time call of benign versus malignant that integrated everything seen during the examination. The second was a checklist of five predefined visual criteria: tumor vessels appearing as tortuous neovessels, hypervascular mucosa, nodular or polypoid masses, papillary projections, and infiltrative lesions marked by irregular mucosa and loss of normal duct architecture. When recorded images or videos were available, blinded investigators independently reviewed the material against the checklist, with disagreements resolved by consensus, adding a layer of methodological rigor to what has historically been a subjective art.

The results against the gold standard of histopathology were striking. Malignancy was ultimately confirmed in 57 of the 68 procedures, reflecting the referral-enriched, high-risk nature of the population. Against that benchmark, the operator’s global impression achieved 84.2 percent sensitivity, 90.9 percent specificity, and 85.3 percent accuracy. Most notable was the positive predictive value of 98.0 percent: when an experienced operator called a lesion malignant on direct visualization, that call was almost always right. The negative predictive value of 52.6 percent, by contrast, shows that a benign-appearing duct cannot safely rule out cancer — tissue sampling remains essential. The authors caution that these predictive values must be interpreted in light of the unusually high cancer prevalence in this cohort.

Among the individual visual criteria, two emerged as the most trustworthy warning signs. An infiltrative appearance showed 90.9 percent specificity and was strongly associated with malignant histopathology, carrying an odds ratio of 13.75 and a positive predictive value of 97.1 percent. Tumor vessels were also significantly linked to cancer, with an odds ratio of 4.57. Hypervascular mucosa, by comparison, offered little discriminatory power. The researchers then explored combined decision rules: using the permissive rule of tumor vessels or infiltrative appearance raised sensitivity to 84.2 percent at moderate specificity, while the restrictive rule requiring both features achieved 100 percent specificity — a powerful rule-in finding when tissue is scarce — albeit with sensitivity dropping to 36.8 percent. These PTCS-specific heuristics remain hypothesis-generating and await prospective validation.

Safety data were equally informative. Adverse events occurred in 10 of 68 procedures, or 14.7 percent, graded using the modified CIRSE classification system. Two events were grade I, five were grade II, and three were grade IV — the latter all infectious complications requiring intensive care-level support such as vasopressors or ventilation, rather than mechanical injury from the instruments themselves. The predominance of low-grade complications underscores the importance of standardized antibiotic prophylaxis, careful biliary decompression, controlled irrigation strategies, and structured post-procedure monitoring for anyone undergoing antegrade cholangioscopy.

The study’s context matters. In patients with surgically altered anatomy — bilioenteric anastomoses or Roux-en-Y reconstructions accounted for nearly a third of the cohort — conventional endoscopic retrograde cholangiopancreatography is often impossible or has already failed. Traditional blind or fluoroscopy-guided biopsies perform poorly for infiltrative, flat, or submucosal tumors, frequently returning nondiagnostic or discordant samples. Prior meta-analyses have shown that cholangioscopy-guided targeted biopsy outperforms fluoroscopy-guided sampling for indeterminate strictures, and consensus guidelines now frame cholangioscopy as a problem-solving tool. What has been missing, the authors argue, is multicenter real-world evidence about how the percutaneous, antegrade version of the technique performs across diverse devices, operators, and health systems — a gap this Brazil-and-Europe network directly addresses.

The investigators are candid about the limitations. The retrospective design limits control of confounding and standardization, and partial verification bias is possible. The high prevalence of malignancy limits generalizability to lower-risk populations, and procedural heterogeneity — different scopes, sheath sizes, sedation protocols, and timing — reflects the reality of a varied referral network but complicates interpretation. Confidence intervals around some analyses were wide, and inter-observer reproducibility was not formally assessed. Still, the single-session design, which avoided within-patient clustering, and the combination of operator impression with structured criteria strengthen the findings considerably.

Looking ahead, the authors call for prospective validation of PTCS-specific optical reporting frameworks, standardized documentation of procedural variables such as tract maturation and irrigation strategy, and quantification of how cholangioscopic findings actually change patient management. Emerging technologies, including standardized image annotation and artificial intelligence-assisted pattern recognition, could sharpen interobserver agreement and refine the visual criteria tailored to percutaneous referral populations. For now, the message for patients with mysterious bile duct blockages is encouraging: a camera threaded through the liver, guided by a trained eye and a disciplined checklist, can bring clarity where scans and standard endoscopy leave only doubt — with a safety profile that is, in most cases, reassuringly benign.

Subject of Research: Diagnostic performance and safety of percutaneous transhepatic cholangioscopy for complex, indeterminate biliary lesions

Article Title: Percutaneous transhepatic cholangioscopy for complex biliary lesions: multicenter real-world diagnostic performance and safety study

Article References: Gonçalves, B., Nunes, T. F., Leitão, L., de Oliveira Leite, T. F., Stefanini, F. S., Fornazari, V. A. V., De Santi, G. F., Pazinato, L. V., Szejnfeld, D., Mosconi, C., Ierardi, A. M., Sousa, M. J., Dezman, R., Krokidis, M., & Hatzidakis, A. (2026). Percutaneous transhepatic cholangioscopy for complex biliary lesions: multicenter real-world diagnostic performance and safety study. CVIR Oncology, 2(1), Article 14. https://doi.org/10.1007/s44343-026-00045-3

Image Credits: AI Generated

DOI: 10.1007/s44343-026-00045-3

Keywords: percutaneous transhepatic cholangioscopy, biliary strictures, cholangiocarcinoma, indeterminate biliary lesions, targeted biopsy, interventional radiology, diagnostic accuracy, adverse events, multicenter study, bile duct cancer, Percutaneous, transhepatic