Countries participating in the International Registry of Acute Aortic Dissection.
Central Message
Thoracic aortic dissections are understudied in low- and lower-middle-income countries.
Collaborative efforts such as the International Registry of Acute Aortic Dissection
may change this reality.
The knowledge surrounding the global epidemiology of thoracic aortic disease is mostly
confined to high-income countries, where thoracic aortic aneurysms (TAAs) have an
incidence of at least 5.3 per 100,000 people per year and acute thoracic aortic dissections
(ATADs) occur in approximately 3 to 4 cases per 100,000 person-years.
1
,
2
The true prevalence of TAAs is likely underestimated because more than 90% of people
who live with TAAs remain asymptomatic until dissection or rupture occurs, which may
explain why epidemiological estimates of TAAs and ATADs are nearly comparable. Nevertheless,
in high-income countries, thoracic aortic surgery already makes up a considerable
share of total cardiac surgical volumes: in the United States, 8% of all cardiac surgery
procedures involve the thoracic aorta.
3
In low- and middle-income countries (LMICs), detailed epidemiological studies on TAAs
and ATADs are lacking, although the overall cardiovascular and aortic disease burdens
are increasing: The global morbidity and mortality due to any aortic pathology increased
by 67.0% between 1990 and 2019, particularly among LMICs, which experienced an increase
of up to 150.6%.
4
These trends are driven by countries’ epidemiological transition away from communicable
(infectious) diseases and toward noncommunicable diseases, with an overlapping transition
period of a double burden. As life expectancy improves, rates of hypertension and
resulting aortic pathology are expected to increase. Between 2000 and 2019, the healthy
life expectancy in sub-Saharan Africa increased by 10 years, with overall life expectancy
increasing even further, contributing to the rise in noncommunicable diseases and
aortic pathology, especially in working-age adults.
5
Unlike high-income countries, LMICs will continue to observe high rates of HIV/AIDS,
syphilis, and tuberculosis for many years to come, each of which may contribute to
aortic pathology in younger populations. Indeed, evidence suggests the age at ATAAD
onset in LMICs is lower compared to high-income countries.
6
Concurrently, traumatic injuries are an important cause of thoracic aortic injury,
responsible for 2% to 3% of deaths from road traffic incidents.
7
Despite possessing only 60% of the world’s vehicles, LMICs face more than 90% of deaths
due to road traffic injuries worldwide.
8
As a result of these unique challenges, an understanding of the thoracic aortic burden
and management in LMICs is crucial to inform health care planning and reduce countries’
aortic morbidity and mortality.
The International Registry of Acute Aortic Dissection (IRAD) is an international,
multicenter effort focused on acute thoracic aortic dissections and recently celebrated
its 25th anniversary. During these 25 years, 97 studies on acute aortic dissections
were published.
9
As such, IRAD has been foundational to informing the clinical and surgical management
of ATADs, with findings informing guidelines and practice worldwide. IRAD’s growth
and scientific contributions are commendable and provide an example for similar initiatives
in other areas of cardiothoracic surgery; however, 1 crucial gap remains: IRAD represents
58 aortic surgery centers in 13 countries, of which 56 centers are based in high-income
countries (Figure 1). Two centers are based in China and India, and are, respectively,
among the world’s highest-volume centers and a private center, thereby not representing
the realities of most centers and patients in LMICs.
Figure 1
Countries participating in the International Registry of Acute Aortic Dissection.
In this article, we summarize access to cardiac surgery in LMICs with a focus on thoracic
aortic surgery and briefly summarize the available evidence on scheduled and emergency
surgical outcomes for thoracic aortic disease in variable-resource contexts. Herein,
we define LMICs according to the World Bank’s Country and Lending Groups classification
for the 2024 fiscal year as countries with a gross national income per capita ≤$13,845.
We acknowledge that LMICs, home to 6.7 billion people, are heterogeneous in terms
of their disease burdens, overall health care capacity, and sociocultural and political
systems. Nevertheless, several key challenges, including insufficient cardiac surgical
capacity, health coverage, and underrepresentation in cardiac surgical research, are
shared, and illustrated through the example of thoracic aortic surgery delivery in
Cameroon, an LMIC in sub-Saharan Africa. We conclude by highlighting opportunities
to generate contextual evidence for management of thoracic aortic disease in LMICs
through IRAD and beyond.
Access to Cardiac Surgery in LMICs
Access to safe, timely, and affordable cardiac surgical care in LMICs is poor because
6 billion people lack access when needed and more than 100 countries and territories
do not have a single cardiac surgeon or cardiac surgical center.
10
,
11
High-income countries rely on 7.15 cardiac surgeons and 2.18 cardiac surgery centers
per million population; by contrast, low-income countries have only 0.04 cardiac surgeons
and 0.04 centers per million people.
11
,
12
Regionally, sub-Saharan Africa is disproportionately affected: the subcontinent has
only 92 cardiac surgery centers to cater for more than 1 billion people. Whereas LMICs
face a substantial mismatch between their cardiac surgical needs and capacity, various
countries continue to show leadership in terms of surgical volumes (eg, the world’s
largest centers are in China and India), procedural costs (eg, centers in India and
Vietnam perform cardiac surgery at as little as $1500-$3000), training programs (eg,
South Africa, Morocco, and Egypt train cardiac surgeons from across the sub-Saharan
African subcontinent), and health coverage (eg, most Latin American countries have
comprehensive health coverage, whereas Nepal has introduced a microinsurance scheme
to enable children, elderly, and those in poverty to access cardiac surgery for free).
13
,
14
The care provided by surgeons in LMICs is often focused on procedures that minimize
resource utilization (eg, less complex congenital heart surgery) and length of stay
(eg, need for postoperative intensive care), and are associated with favorable outcomes
(eg, lower-risk procedures). This is the result of small overall health budgets and,
especially, a lack of prioritization of and investment into cardiac surgical services.
10
Indeed, communicable diseases make up more than half of all global health financing
for less than one-third of deaths in LMICs; by contrast, noncommunicable diseases,
which notably include cardiovascular disease, receive <2% of funds but account for
74% of all deaths.
15
,
16
This discrepancy between disease burden and political and economic action is sustained
by both a focus on smaller, population-level interventions providing potentially faster
marginal health gains, despite not necessarily having greater cost-effectiveness,
and prevailing myths surrounding care for complex conditions, such as cardiac surgical
disease.
17
As such, noncommunicable diseases are on the rise in LMICs without concurrent health
systems strengthening efforts to manage this growing burden. Primordial, primary,
and secondary preventive efforts are key to mitigate cardiovascular disease burdens,
but cannot eradicate cardiovascular disease nor meet the needs of those already living
with cardiac surgical disease. Scaling cardiac surgical services requires considerable
time for training teams and setting up the necessary infrastructure; waiting to act
will only cause greater health system gaps in the future.
Thoracic Aortic Surgery in LMICs
Reports from LMICs without local cardiac surgical capacity are rare but illustrate
the dire situation with patients expiring or requiring costly and traumatizing travel
abroad for a glimpse of hope of survival.
18
,
19
In LMICs with local cardiac surgical capacity, thoracic aortic pathology is less frequently
managed compared with high-income countries, whether as a result of no diagnosis (eg,
death in the community or lack of imaging), no or delayed referral, limited emergency
care and surgery capacity, and/or a lack of staffing or resources.
20
Despite these challenges, select centers perform cardiac surgery for thoracic aortic
pathology in both scheduled and emergency settings. Although outcomes differ, experienced
but lower-volume centers are able to achieve favorable outcomes.
20
For example, several publications from Cameroon illustrate the ability to perform
scheduled and emergency thoracic aortic surgery in an LMIC influenced by political
instability and conflict.20, 21, 22 There, the local cardiac-aortic surgeon (senior
author of this manuscript: Dr Mvondo) was trained abroad and acquired further expertise
through visiting team partnerships, now independently performing thoracic aortic procedures
in Cameroon. Between 2010 and 2018, 28 patients were operated on for TAAs (N = 18
[64.3%]), ATADs (N = 9 [32.1%]), and a nonsyphilitc pseudoaneurysm (N = 1 [3.6%]).
21
After surgery, the 30-day mortality was 10.7% (5.6% for TAAs; 22.2% for ATADs). More
recent findings suggest that, despite delayed referrals and management of patients
in the subacute or chronic phase, composite aortic root replacement for type A ATADs
(n = 12) with 75% (n = 9) of patients undergoing concomitant aortic arch surgery had
an operative mortality of 16.7%, thus comparing favorably to outcomes reported by
IRAD.
9
,
20
Lastly, aortic root enlargement with double (mitral and aortic) valve replacements
(n = 25) have been successfully performed in young patients (mean age at surgery,
23.3 ± 12.9 years) with predominantly (96%) rheumatic heart disease; the 8% operative
mortality rate was higher than that observed in nonrheumatic, high-income country
series (<2%).
22
,
23
Patients’ experiences and outcomes could be optimized even further if timely screening,
diagnostics, and more experienced and trained professionals across the care continuum
were available. Moreover, locoregional registries to track thoracic aortic surgical
outcomes in the sub-Saharan subcontinent could provide further insight into the optimal
management of local patients to inform quality improvement initiatives.
Data from centers in most LMICs, especially low- and lower-middle-income countries,
are limited, resulting in the contemporary evidence and clinical guidelines being
rooted in populations and high-resourced contexts from (mostly) high-income countries.
By contrast, patients managed in LMICs are generally younger, have higher rates of
uncontrolled hypertension, and poorer adherence to medical therapy compared with patients
in high-income countries.
23
Moreover, aortic consequences of endemic diseases, such as HIV/AIDS, syphilis, and
tuberculosis, as well as genetic and biological differences require further study.
As such, it is unclear whether existing guidelines may be directly applied in populations
unrepresented in the evidence base.
It must also be acknowledged that the costs, risks, and needs of thoracic aortic surgery
are considerable. In variable-resource contexts, where triage decisions have to be
made amidst considerable cardiac surgical waiting lists, noncardiac surgical health
agendas, and limited budgets, the decision to perform complex cardiac surgery is potentially
contentious.
24
From a purely utilitarian point of view, which seeks to maximize health benefits across
the population for a given amount of a good (eg, health budget), thoracic aortic surgery
may not be high on the list of priorities. Conversely, egalitarian and prioritarian
views may suggest that those worst off should not be neglected and the rule of rescue
comes at the forefront; indeed, conditions that are as life-threatening as thoracic
aortic pathology would fall under such an umbrella. Regardless of the ethical lens
taken, investments into thoracic aortic (and broader cardiac) surgical capacity do
not need to come at the cost of other health priorities. LMICs’ spending on health
care as part of their health budgets remains considerably below past commitments,
whereas global health financing by foreign aid agencies and private organizations
should be directed toward overall health systems instead of earmarked to individual
disease silos that do not necessarily match local needs.
12
,
15
,
24
The heterogeneous needs and models to establish cardiac centers fall outside the scope
of this article but have been described elsewhere.
10
Similarly, thoracic aortic programs in LMICs have different origins, ranging from
their introduction through the aortic training of local cardiac surgeons (as observed
in Cameroon) to twinning programs between centers.
Moving the Center of Thoracic Aortic Research Gravity
Evidence from and guidelines for managing populations in high-income countries cannot
be assumed to translate directly to the distinct populations and contexts in LMICs,
requiring a shift in thoracic aortic research paradigms. Beyond clinical challenges,
underreporting of data from LMICs is partially the result of other time pressures
and limited research capacity and funding on the ground, as well as the traditional
barriers to academic collaborations and publishing.
24
Addressing these hurdles will require proactive support and increased opportunities
by existing initiatives to level the playing the field and more comprehensively inform
our understanding of ATAD in different populations and regions of the world.
Participation in existing database efforts, such as IRAD, can shed light on the current
thoracic aortic practices in LMICs. However, barriers to participation must be thoroughly
assessed and addressed to avoid skewing of participation toward well-resourced centers
that may not be representative of the realities of resources and patient presentations
in most cardiac centers in LMICs. Barriers may include a lack of electronic health
records, linguistic challenges for data entry, administrative and legal issues, and
potential costs surrounding human resources, data infrastructure, or database participation.
Addressing these barriers may involve efforts by overarching data infrastructures,
organizations, or societies to waive or subsidize costs and provide logistical support
to overcome any learning curve. In addition, translations of data input, information,
and capacity-building should be provided to move away from an anglophone-dominated
research field, which excludes a considerable part of LMICs where English is not frequently
spoken (eg, Latin America and francophone African countries).
Research efforts may further be supported by clinical efforts to provide virtual continued
medical education. In recent years, there has been a surge in online educational platforms
and webinars in cardiac surgery, many of which are widely attended across the globe,
including by health care professionals from LMICs.
25
For congenital heart surgery, the International Quality Improvement Collaborative
has provided a platform for participating congenital heart surgery centers and teams
to not only contribute LMIC data to an international outcomes registry but also receive
regular training for all team members through recurring webinars.
26
Such an approach engages not merely surgeons but can also ensure research empowerment
of all health care professionals engaged in thoracic aortic care and provides further
opportunity for clinical team-based training. This may enable aortic team models to
be more embedded across the globe and further optimize patient outcomes. In addition,
in-person educational opportunities and scholarships, such as those supported by the
Thoracic Surgery Foundation, as well as twinning programs between cardiac centers
with a focus on thoracic aortic surgery should be further encouraged and supported
to scale thoracic aortic surgical care in LMICs.
As thoracic aortic surgical efforts and research scale in LMICs, a focus on research
equity will be paramount. Evidence from the global surgical literature suggests that
authors from high-income countries are disproportionately in first and last authorship
positions for research conducted in LMICs,
27
suggesting potential power imbalances or a lack of sponsorship of local authors. Although
this may be the result of limited research experience and training, LMIC authors should
be supported in developing the research and writing skills necessary to lead their
own research efforts.
27
Such research capacity-building may be done in the context of international partnerships
with support of high-income country experts, but should, akin to budding cardiac surgical
centers, move toward south-south partnerships and, ultimately, full local ownership.
Additionally, professional societies play a leading role in raising awareness of the
issue of thoracic aortic care in LMICs. For example, annual meetings are increasingly
placing global cardiac surgery discussions on their agendas
28
; in the future, conference organizers may consider thoracic aortic disease as part
of these sessions or at dedicated aortic meetings, where such topics remain undiscussed.
Furthermore, existing societal efforts, such as the Cardiac Surgery Intersociety Alliance,
29
can better recognize and integrate all aspects of the cardiac surgical care continuum
to recognize the systems-wide issues influencing practice, including health policy,
health care financing, supply chains, and lifelong care into the community.
Lastly, and perhaps most importantly, patients must remain at the center of any global
cardiac surgical effort. Among patients with thoracic aortic disease, proper informed
consent and shared decision-making practices are essential and must be tailored to
patients’ and families’ level of health literacy. In addition, because follow-up after
thoracic aortic care is challenging even in high-income countries, telemedicine modalities
must be explored. In LMICs, there is a wide availability of smartphones in part due
to their use for a variety of purposes, including education and mobile payments; as
such, mobile health and telemedicine in LMICs have been successful for a range of
cardiovascular prevention and care purposes.
30
Conclusions
The efforts of IRAD in the past 25 years are remarkable and have contributed to many
lives saved around the world. Geographically expanding IRAD’s efforts to underrepresented
countries and populations in the next 25 years can help dissect the realities facing
the majority of the world’s population and exponentially increase the influence of
IRAD through both clinical evidence and academic and clinical capacity-building.
Conflict of Interest Statement
The authors reported no conflicts of interest.
The Journal policy requires editors and reviewers to disclose conflicts of interest
and to decline handling manuscripts for which they may have a conflict of interest.
The editors and reviewers of this article have no conflicts of interest.