Onassis Cardiac Surgery Center

What Onassis Cardiac Surgery Center does

Onassis Cardiac Surgery Center (Ωνάσειο Νοσοκομείο) is a Greek public non-profit hospital and the largest specialized cardiac surgery center in Southeast Europe, operated as a Private Legal Entity (ΝΠΙΔ) under supervision of the Greek Ministry of Health. Originally donated by the Onassis Foundation in 1992 and opened in 1993, the hospital was substantially expanded in October 2025 into a 185-bed / 54-ICU-bed complex comprising three units: the Onassis Cardiac Surgery Center, the Onassis National Transplant Center (ΩΕΜΕΚ), and Onassis Pediatrics (Onassis Παίδων). It serves Greek citizens as the national referral center for adult and pediatric cardiac surgery, interventional cardiology, heart and lung transplantation, and pediatric solid-organ transplantation, and is the only hospital in Greece certified for the development and provision of cardiac surgery and cardiology services.

The hospital's core technology stack centers on being the first fully digitized hospital in Greece, integrating artificial intelligence across imaging, clinical workflows, and patient data management. Proprietary or licensed-differentiated components include the Syngo digital imaging platform (CT, MRI, ultrasound, angiography), a SOMATOM Drive dual-source CT scanner, a MAGNETOM Sola MRI with BioMatrix patient-adaptive technology, ARTIS icono biplane and ARTIS Pheno robotic angiography systems, an ACUSON Origin cardiovascular ultrasound with BioAcoustic technology, MOBILETT Elara Max portable X-ray, hybrid operating theaters, and a new cold static preservation system for cardiac grafts deployed in 2026. AI is used for computer vision in imaging optimization, process automation across imaging workflows, and predictive analytics supporting clinical decision-making and personalized therapeutic strategies.

Revenue is generated primarily through reimbursement from Greece's national social insurance funds (EOPYY) and private insurance for covered medical services, supplemented by capital donations from the Onassis Foundation (€82M for the new building, €25M for medical equipment, €10M planned for the "Hospital of the Future" program). The center fulfills a social-mission mandate by providing free cardiac and transplant care to uninsured and impoverished children referred from Aghia Sophia Children's Hospital. Go-to-market is institutional: patients are accessed through outpatient clinics (phone scheduling at 210 94 93 000), a dedicated Emergency Department (TEP), and a hospital-to-hospital referral network across Greece, with recent expansion into military medicine via a strategic cooperation with the 251 General Military Hospital of the Hellenic Air Force.

Name

Onassis Cardiac Surgery Center

Legal name

Ωνάσειο Νοσοκομείο

Website

https://onasseio.gr

Company type

Private

Founded year

1992

Operating status

Operating

Headcount range

1–10 employees

Short description

Onassis Cardiac Surgery Center is a Greek public non-profit hospital and the largest specialized cardiac center in Southeast Europe, serving adult and pediatric patients through cardiac surgery, interventional cardiology, and organ transplantation. It operates as Greece's first fully digitized hospital with integrated AI diagnostics.

Ownership category

akta.pro rank

Product category

Cardiac Surgery Services

NAICS

Specialty (except Psychiatric and Substance Abuse) Hospitals (62231), Specialty (except Psychiatric and Substance Abuse) Hospitals (622310), Specialty (except Psychiatric and Substance Abuse) Hospitals (6223)

SIC

Services-Hospitals (8060), Services-General Medical & Surgical Hospitals, Nec (8062)

akta.pro primary industry

Cardiac & Cardiothoracic Specialty Hospitals (HLAFAHAA)

akta.pro secondary industries

Transplant Specialty Hospitals (HLAFAHAE), Cardiovascular / Cath Lab & Electrophysiology Centers (HLAFAIAI)

Keywords

• Cardiac surgery services
• Pediatric cardiology
• Heart transplantation
• Interventional cardiology
• Organ transplant services

Headquarters

HQ city

Kallithéa

HQ country

Greece

HQ region

Europe

Offices1 record

Markets served

GTM type

B2C

Offering type

Services

Cost components

Personnel, Infrastructure, Technology or R&D, Operations

Revenue model

1. Public Healthcare Reimbursement: As a public hospital operating under the Greek Ministry of Health, the center generates revenue through reimbursement from public social insurance funds (EOPYY) and private insurance providers for covered medical services. Patient admissions and treatments are billed through the national health system.
2. Charitable Care (Uncompensated): The center provides free cardiac care to uninsured and impoverished pediatric patients referred from Aghia Sophia Children's Hospital without any financial charge to families, in fulfillment of its social mission. This represents a cost center rather than revenue generation.
3. Onassis Foundation Donation (Capital): The Onassis Foundation provided a landmark donation of €82 million for the construction and equipment of new hospital facilities, including €25 million for state-of-the-art medical equipment and digital transformation. Additional €10 million is planned for future innovation investments under the 'Hospital of the Future' program.

Pricing tiers

Go-to-market motion1 record

Distribution channels4 records

Marketing channels6 records

Core offering

Onassis Cardiac Surgery Center is a public specialized hospital delivering comprehensive cardiac surgery, interventional cardiology, pediatric cardiac care, and solid organ transplantation (heart, lung, and pediatric kidney) services in Athens, Greece. As the national referral center for cardiac and cardiothoracic cases, it operates the first fully digitized hospital infrastructure in Greece with AI-integrated diagnostics, hybrid operating theaters, and a Heart and Lung Transplant Unit, while also providing free cardiac care to uninsured children under its social mission.

Differentiator

Problem solved

Functional benefit

Brands

• Ωνάσειο Καρδιοχειρουργικό Κέντρο (Onassis Cardiac Surgery Center): The main cardiac surgery and cardiology center, operating since 1993, offering advanced cardiac surgery, interventional cardiology, and cardiac care services.
• Ωνάσειο Εθνικό Μεταμοσχευτικό Κέντρο (Onassis National Transplant Center)
• Ωνάσειο Παίδων (Onassis Children's Hospital)

Products and services

• Adult Cardiac Surgery (Onassis Cardiac Surgery Center) Specialized adult cardiac surgery service delivered through the Onassis Cardiac Surgery Center (ΩΚΚ), offering advanced cardiac procedures, heart transplantation (since 1995), and comprehensive cardiac care as the largest cardiac surgery unit in Southeast Europe.
• Interventional Cardiology Diagnostic and interventional cardiology procedures including cardiac catheterizations, performed by the Interventional Cardiology Department using state-of-the-art imaging and robotic angiography systems (ARTIS Pheno, ARTIS icono).
• Pediatric Cardiac Care (Onassis Children's Hospital / Ωνάσειο Παίδων) Comprehensive pediatric cardiology and cardiac surgery service for newborns, infants, and children with congenital heart disease, delivered through a 33-bed pediatric clinic with 12 PICU beds; covers the largest share of pediatric cardiac surgery cases in Greece with over 15,500 pediatric hospitalizations recorded and outcomes tracked on the European Pediatric Cardiac Surgery Platform.
• Solid Organ Transplantation (Onassis National Transplant Center / ΩΕΜΕΚ) Solid organ transplantation service delivering heart, lung, and pediatric kidney transplants as Greece's national transplant hub, operated in collaboration with the Hellenic Transplant Organization (EOM); heart transplantation program operating since 1995, lung transplantation program since 2020 (in collaboration with Attikon Hospital), with 50 lung transplants completed since launch and 12 heart transplants plus 8 lung transplants performed in 2024 alone.
• Free Charitable Cardiac Care for Uninsured Children Social-mission service providing free cardiac care — including surgeries, catheterizations, and transplant services — to uninsured and impoverished pediatric patients referred from Aghia Sophia Children's Hospital, with no financial burden to families.

Quantifiable outcome

• 15,500+ pediatric hospitalizations completed, covering the largest share of pediatric cardiac surgery cases in Greece
• +4 more outcomes

Named customers3 records

Segments4 records

Ideal customer profiles5 records

Technology focussed No

API detail

Has API

No

API docs

API detail

Core technology

AI maturity

App detail

AI capability6 records

Feature11 records

Partnerships

Eight partnerships are on record, tiered minor and core.

• International Humanitarian Aid NGO 'Panagia' of CyprusminorStrategic or Co-development Partner · 1 July 2025Onassis Hospital participated in a multi-dimensional humanitarian mission to Toliara, Southern Madagascar, in cooperation with the International Humanitarian Aid NGO 'Panagia' of Cyprus and under the auspices of the Patriarchate of Alexandria. An 8-member medical team provided medical-nursing care, donated medical equipment (10 ICU beds, 10 defibrillators, 2 cardiographs), and conducted CPR training, ultrasound training, and clinical lectures.
• 251 General Military Hospital of Air Force (251 ΓΝΑ)coreStrategic or Co-development Partner · 3 June 2025A strategic cooperation memorandum was signed between Onassis Hospital and 251 General Military Hospital of Air Force. The agreement provides for the care of selected cardiac and cardiothoracic cases from 251 ΓΝΑ, including active-duty Air Force personnel, their family members, and retired Air Force officers at Onassis facilities. Cooperation also extends to scientific research and education, including participation of 251 ΓΝΑ medical and nursing staff in specialized training programs.
• Transatlantic Educational Network (TEN)minorStrategic or Co-development Partner · 1 January 2024The Anesthesiology Department participates in the Transatlantic Educational Network (TEN) alongside leading hospitals from the USA and Europe including Massachusetts General Hospital/Harvard, Yale University Hospital, Cleveland Clinic Foundation, Harefield Hospital/Imperial, Royal Papworth/Cambridge, and Bad Oeynhausen/Ruhr-University Bochum. The program facilitates knowledge exchange in clinical, educational, and research domains, with participating institutions exchanging speakers via web platform.
• Great Ormond Street HospitalcoreStrategic or Co-development PartnerOnassis collaborates with Great Ormond Street Hospital, one of Europe's largest pediatric hospitals with a world-renowned Pediatric Cardiac Surgery and Cardiology unit. Under Onassis Foundation sponsorship, the collaboration includes external evaluation aimed at continuous improvement of medical care provided to pediatric patients. The partnership leverages the UK hospital's expertise to enhance quality standards at Onassis Pediatrics.
• Hellenic Transplant Organization (EOM)coreStrategic or Co-development PartnerThe Onassis National Transplant Center (ΩΕΜΕΚ) operates under the national transplant strategy coordinated by the Hellenic Transplant Organization (EOM). Collaboration focuses on developing a national network of transplant cooperation, supporting existing transplant structures, enhancing healthcare professional training, and promoting organ donation culture. The partnership drives Greece's transformation into a center of excellence for organ transplantation.
• Attikon University HospitalcoreStrategic or Co-development PartnerOnassis collaborates with Attikon Hospital for the Lung Transplantation Program, which has been operating since 2020. The program has conducted 50 total lung transplants, including a cross-border transplant from Romania in August 2024.
• Laiko General HospitalminorStrategic or Co-development PartnerCollaborates with Laiko General Hospital for pediatric kidney transplant services, where the Onassis Hospital's Pediatric Nephrology and Transplant Department works in coordination with Laiko's Kidney Transplant Clinic.
• Aghia Sophia Children's HospitalcoreStrategic or Co-development PartnerCoordinates with Aghia Sofia Children's Hospital for referrals of uninsured pediatric cardiac patients who receive free treatment at Onassis without financial burden to their families. Also collaborates on pediatric kidney transplant services.

Scale indicators8 records

Recent moves10 records

Expansion highlights6 records

Direct peers

• Aghia Sophia Children's Hospital: Greece's largest pediatric hospital and Onassis's referral partner for uninsured pediatric cardiac patients and pediatric kidney transplants. Directly comparable in serving complex pediatric cases within the Greek public system.
• Harefield Hospital: One of Europe's largest cardiothoracic transplant centers, part of Royal Brompton & Harefield NHS Trust. Closely comparable to Onassis in heart and lung transplantation focus, interventional cardiology, and academic medical training.
• Attikon University Hospital: Greek university hospital collaborating with Onassis on the Lung Transplantation Program since 2020. Directly comparable as a Greek tertiary hospital involved in advanced cardiac and transplant care, and an active operational partner.
• Laiko General Hospital: Major Athens tertiary hospital that collaborates with Onassis on pediatric kidney transplant services. Comparable as a Greek public academic hospital providing advanced surgical and transplant care.
• Royal Papworth Hospital: UK NHS specialist cardiothoracic hospital and major heart and lung transplant center. Directly comparable to Onassis as a dedicated cardiac and transplant specialty hospital with deep research and education programs, and a named partner in Onassis's Transatlantic Educational Network.
• Bad Oeynhausen Heart and Diabetes Center (HDZ NRW): German specialty cardiac hospital (Ruhr-University Bochum affiliation) with one of Europe's largest cardiac surgery and transplant volumes. Closely comparable to Onassis as a European specialty cardiac center and TEN network participant.
• Great Ormond Street Hospital: World-leading UK pediatric specialty hospital with a renowned Pediatric Cardiac Surgery and Cardiology unit. Directly comparable to Onassis Pediatrics, and an active collaboration partner for external quality evaluation.

Broad incumbents

• Massachusetts General Hospital: Harvard-affiliated academic medical center with leading cardiology, cardiac surgery, and transplant programs. Peer to Onassis in advanced cardiac care delivery and academic collaboration, and a TEN network partner.
• Cleveland Clinic: US-based broad incumbent health system with a globally ranked cardiology and cardiac surgery program and significant transplant volume. Comparable to Onassis as a flagship cardiac destination, though operating at a vastly larger scale across multiple specialties.
• Yale New Haven Hospital: US academic medical center with advanced cardiac and transplant services. Comparable to Onassis through its TEN educational partnership and as a broad incumbent with specialty cardiac depth.

Market position

Strengths4 records

Weaknesses5 records

Competitive moat6 records

Key risks5 records

Key highlights6 records

Customer concentration

• LinkedInlinkedin.com/company/onassis-cardiac-surgery-center

Revenue estimate

Valuation estimate

Number of profiles

Profiles7 records

Funding overview

Funding rounds

Investors

Funding detail is available on the Subscription and Enterprise plan.Contact sales →

M&A

Investments

M&A and investment is available on the Subscription and Enterprise plan.Contact sales →

Frequently asked questions about Onassis Cardiac Surgery Center