Japan's aging population is placing unprecedented demands on cardiovascular care, with calcified coronary arteries emerging as a major challenge in percutaneous coronary intervention (PCI), the minimally invasive procedure used to treat blocked heart arteries. Heavily calcified lesions—hardened plaque deposits that resist standard balloon angioplasty and stenting—complicate up to 20-30% of PCI cases in elderly patients, leading to higher risks of procedural failure, stent underexpansion, and long-term complications like restenosis or thrombosis. Juntendo University researchers have now provided compelling evidence that a pivotal 2020 policy shift has made advanced treatment more accessible without sacrificing safety.

This development underscores Juntendo University's leadership in cardiology research, leveraging the nation's comprehensive Japanese PCI (J-PCI) registry to deliver real-world insights that shape clinical practice and health policy.

Understanding Rotational Atherectomy in PCI

Rotational atherectomy (RA), often called 'rotablation,' employs a high-speed diamond-coated burr (typically 1.25-2.5 mm in diameter) rotating at 140,000-180,000 RPM to ablate calcified plaque, creating a smooth luminal path for subsequent stenting. Introduced in the 1980s, RA is recommended by global guidelines for severe calcification where balloons fail, improving procedural success from ~70% to over 90% in complex cases.

In Japan, where the population over 65 exceeds 29%—the world's highest—calcified lesions are prevalent, affecting roughly 17-35% of PCI patients. Traditional PCI tools struggle here: balloons may rupture, stents underexpand (increasing thrombosis risk by 2-3 fold), and surgery carries 3-5% mortality. RA addresses this by mechanically modifying calcium, but pre-2020 access was limited.

Pre-2020 Restrictions: A Barrier to Care

Prior to April 2020, Japan's Ministry of Health, Labour and Welfare (MHLW) and the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) mandated RA only in 'training facilities': high-volume centers performing ≥200 PCIs annually with on-site cardiac surgery backup. This excluded ~60% of hospitals, forcing patient transfers—delays averaging 2-4 days that elevate mortality risk by 10-20% in acute cases—and geographic disparities, particularly in rural areas.

Only board-certified operators in these elite centers could perform RA, limiting annual cases to ~4-6% of PCIs despite rising need. Low-volume hospitals treated calcified lesions conservatively, often with suboptimal outcomes: procedural success ~75% vs. 95% with RA.

The 2020 Policy Revision: Key Changes

In response to clinician advocacy, CVIT and MHLW revised criteria in April 2020. Board-certified PCI operators completing CVIT-mandated RA training (hands-on workshops, ≥20 supervised cases) can now perform RA in non-training facilities (<200 PCIs/year, no surgical backup). Facilities must conduct regular training if performing ≤10 RAs biennially.

This democratized access: by 2023, RA-capable hospitals rose from ~500 to 781 (66% of 1,181 PCI sites). The change aligned with Japan's universal health insurance, reimbursing RA uniformly while emphasizing operator competency over facility volume.

Juntendo University's Landmark Study

Led by Assistant Professor Tadao Aikawa from Juntendo University Graduate School of Medicine's Department of Cardiovascular Biology and Medicine, a multi-institutional team analyzed 1,161,862 PCIs from the J-PCI registry (covering >90% of Japan's ~600,000 annual PCIs) across 1,243 hospitals (2019-2023). Collaborators included Kyoto University, Harvard-affiliated Beth Israel Deaconess, and CVIT experts.

Using quasi-experimental difference-in-differences (DiD) design—comparing training (control) vs. non-training (exposed) facilities pre (2019-2020) and post (2021-2023) revision—the study assessed if expanded access compromised safety. Published March 2026 in JACC: Advances (full paper), it validates the policy empirically.

Study Methods: Rigorous Real-World Evidence

DiD modeled policy impact via interaction term (facility × time), adjusting for age, comorbidities (diabetes 40%, hypertension 70%), lesion complexity, and hospital traits. Primary endpoint: in-hospital mortality. Secondary: composite death/complications (MI, thrombosis, tamponade, shock, surgery, bleeding transfusion).

Sensitivity analyses used observed-to-expected (O/E) mortality ratios from a training-facility prediction model. Exploratory RA-specific cohort confirmed trends. Robustness against COVID-19 confounders (parallel trends verified) strengthens causal inference.

Key Results: Increased Access, Stable Safety

RA use rose from 4.2% (2019) to 5.2% (2023), with non-training facilities jumping from 0% to 2.7%. Yet, 34% of hospitals still performed no RA, highlighting adoption gaps.

In-hospital mortality edged up slightly (1.6-1.9% both groups), but DiD showed no significant difference (adjusted P=0.55). Composite complications stable in non-training (3.2-3.3%), rose modestly in training (3.1-3.7%; P=0.006 interaction). RA-specific: training facilities had lower mortality (OR 0.66).

O/E ratios increased post-revision in non-training (1.13→1.26), stable in training—suggesting case selection or learning curve, not policy failure. Press release highlights no safety compromise.

Implications for Patients and Healthcare Equity

For Japan's 1.3 million annual CAD patients (many elderly, rural), local RA reduces transfers, cutting risks/delays. Procedural success nears 95%, stents expand optimally, long-term events drop 20-30% vs. non-RA.

Policy proves operator training trumps volume/surgery backup, a model for aging nations. Reduced disparities: rural PCI mortality gaps narrowed ~15% post-revision.

Juntendo University's Cardiology Excellence

Founded 1838, Juntendo University boasts a top-tier cardiology department, training 20% of Japan's interventionalists. Recent outputs: RA registries, imaging innovations. Aikawa's team exemplifies translational research, influencing CVIT guidelines.

Juntendo's Urayasu/Shizuoka hospitals pioneer complex PCI, with RA volumes >100/year. This study cements its policy-shaping role.

Expert Perspectives and Quotes

"Expanding RA use in newly accredited non-training facilities could increase complications, but our data verifies safety," says Aikawa. "Regulators can relax restrictions with enforced training—evidence-based reform model."

CVIT echoes: Revision boosted operators/facilities, outcomes stable. Kyoto's Yamaji notes: "Low adoption persists; education key." Harvard's Kuno adds global relevance for calcified PCI.

Challenges and Future Directions

Adoption lags (33% no RA); barriers: training access, cost (¥500k/case), device familiarity. O/E rise suggests initial learning; mandatory audits proposed.

Emerging: Orbital atherectomy (1.5%), intravascular lithotripsy (Shockwave, registry-limited). Juntendo eyes hybrid strategies, AI lesion prediction. Policy 2.0: Incentives for rural RA, volume thresholds revisited.

Photo by Fratto Kenchiku on Unsplash

Broader Impact on Japanese Higher Education and Health

Juntendo exemplifies universities driving policy via registries/real-world evidence. Amid Japan's doctor shortage (2.5/1000 vs. OECD 3.5), such research optimizes resources, supports universal care.

Globally, informs aging societies (e.g., Italy, Korea). Juntendo's work fosters cardiologist training, jobs in interventional fields.