Background 

Cardiac disease is a major cause of morbidity and mortality in the African population. In fact, 38% of all non-communicable disease (NCD) related mortality in Africa is reportedly due to cardiac disease or cardiovascular disease.1 Furthermore, the African continent has yet to rid itself of cardiac complications related to rheumatic fever and rheumatic heart disease.2 Therefore, medical therapy alone might be insufficient for cardiac disease management, necessitating surgical intervention in some cases, but as with most major surgical procedures, cardiac surgery is not without risks.
Major postoperative complications including mortality, cardiovascular complications, renal failure, intensive care unit admission, reoperation, and sepsis/infection are on the rise. As these postoperative complications continue to rise, the uncertainty about the rate of their occurrence has gravely limited the ability to plan for any mitigation strategies and interventions.

A continental audit of cardiac surgery procedures and perioperative complications is needed. Information from this process can be used to build capacity for cardiac surgery in the African continent. It can also be used to drive quality improvement initiatives, and to provide more accurate information on postoperative complications of patients undergoing cardiac surgery in this setting.

Study Objective

The primary objectives of this study are:
1. To determine the in-hospital mortality (28-day in-hospital mortality) rate for patients undergoing cardiac surgery in Africa.
2. To determine the incidence of in-hospital postoperative complications in adult cardiac surgical patients in Africa

The secondary objectives include:
1. To determine the rate of mortality on the day of surgery for patients undergoing cardiac surgery in Africa.
2. To describe the relationship between cardiac postoperative complications and postoperative mortality.
3. To describe the proportional contribution of communicable, non-communicable diseases and traumatic injuries to in-hospital mortality and critical care admissions in Africa.
4. To develop a contextual preoperative adult cardiac mortality prediction tool.

Study Design

A 28-day, prospective, observational African national multi-centre cohort study of all (adult and paediatric) patients undergoing open and closed cardiac surgery.

Data on the characteristics of sites providing cardiothoracic surgery and anaesthesia, and infrastructure (cardiothoracic department, cardiology department, functional cardiothoracic surgery theatres) in the recruited hospitals will be collected.

Importance of this Study

The differences in the surgical characteristics and the predictors of morbidity between SASOS and EuSOS suggested that African surgical outcomes data was necessary to identify predictors of morbidity which could be targeted to make surgery safer in Africa, and potentially in other lower- and middle-income countries across the globe. It can be posited that, the need of research that will identify predictors that may be targeted to make cardiac surgeries safer in Africa is even more pronounced. Only once we understand the complexity, and the burden of morbidity and mortality associated with cardiac surgery in Africa will we be able to allocate resources appropriately and finally consider interventions to improve patient outcomes. This study therefore has important public health implications for Africa.

Study Dates

Data collection for the study will start in March 2026. National leaders will determine (with their teams) the start date for their country/territory.

FAQs

Administrative Questions

What is the screening log?

All studies need to report the number of eligible patients during the recruitment period. This is the screening log. It is important that the ACSOS Hospital Lead Investigator reports the number of eligible ACSOS patients from the previous 24 hours in the screening log every morning.

Where can I find all the up to date study documents?

All study documents are available on the ACSOS Website (https://asos.org.za/index.php/acsos).

What is APON and why do I need to register on this platform?

APON is a digital platform designed for researchers in Africa to connect, share and collaborate on various research projects across the continent. To register, go to: https://periopnetwork.org

Which CRFs need to be completed for the study?

When recruiting, a CRF for every patient and a daily CRF for the number of eligible patients (the screening log) needs to be completed. Before recruitment starts, a hospital information document also needs to be completed.

Enrolment/Recruitment Questions

What are the inclusion criteria for the study?

All consecutive patients admitted to participating centres undergoing elective and non-elective open and closed cardiac surgery commencing during a 28-day study cohort period with a planned overnight hospital stay following surgery. The recruitment week will run between March and June 2026, with the option to extend the recruitment period if needed.

Which patients should be excluded from the study?

Patients undergoing planned day-case surgery or radiological procedures not requiring anaesthesia.

Are interventions where there was not an anaesthetic given included? (e.g. coronary stents under sedation given by a cardiologist)

Yes we are collecting data from such cases.

Is a bedside septostomy in the NICU included? Baby sedated by NICU Intensivist and procedure done by paeds cardiologist.

Yes this may be included, as a closed cardiac procedure.

On the CRF procedure list under acquired vs congenital, are these a list of all the surgical procedures to be included in the study?

Yes, these are broadly represented

Are procedures not listed on the procedure list to be excluded? (e.g. Coronary stenting, atrial septostomy, RVOT stent, PDA stent or ligation should be distinguished?)

There is provision for PDA ligation. A PDA stent would possibly be as part of stage one of palliation that may include bridging, stents, and banding. Atrial septostomy would be a palliative procedure.

Should syndromic, paediatric congenital and grown up congenital heart be included in the list of procedures as they are patient categories not surgical procedures?

Syndromic, paediatric congenital and grown up congenital heart should be included with the lesion, these are important in risk stratification and scores. Also important to add whether it is cyanotic.

CRF/Definitions Questions

Do you have any definitions document for the study/CRF terms?

A study definitions document has been prepared and can be accessed here

Can you define anaesthetic as sometimes the sedation doses are quite high? Does an anaesthetist have to be present? Is the presence of an anaesthetic doctor indicative of the fact that an anesthetic was given? Is sedation included? And what separates sedation from an anaesthetic?

We should use the standard definitions of an anaesthetic and sedation.
General Anesthesia: state of complete unconsciousness, unresponsiveness, and with no memory of the procedure
Sedation: ranges from minimal (relaxed but fully awake and able to talk) to deep (dozing heavily, though can still be roused with physical or verbal stimuli)

There is a section that asks for the anaesthetic/ sedationist practitioner as in some countries there are nurse practitioners

Please explain what 30 day in-hospital mortality means.

Mortality in hospital within 30 days of admission for those who stay for long periods in hospital; with a cutoff at 30 day for those staying for more than 30 days. Once discharged, if this falls before 30 days, mortality out of hospital for the index admission cannot be included.

Participating Countries and Nations

Countries and nations confirmed to be participating in ACSOS:

  • Algeria

  • Angola

  • Benin

  • Botswana

  • Burkina Faso

  • Burundi

  • Cameroon

  • Côte d'Ivoire

  • Democratic Republic of the Congo

  • Egypt

  • Ethiopia

  • Gambia

  • Ghana

  • Kenya

  • Libya

  • Malawi

  • Mali

  • Mauritania

  • Mauritius

  • Morocco

  • Mozambique

  • Niger

  • Nigeria

  • Senegal

  • Somalia

  • South Africa

  • Sudan

  • Tanzania

  • Tunisia

  • Uganda

  • Zambia

  • Zimbabwe

    • If you want to participate in the ACSOS Study, feel free to contact us at This email address is being protected from spambots. You need JavaScript enabled to view it.