First Series of Ascending Aorta Surgery in a Sub-Saharan African Country (Benin) ()
1. Introduction
Diseases of the thoracic aorta, notably thoracic aortic aneurysm (TAA) and acute aortic dissection (AAD), are of growing concern worldwide. In high-income countries, the incidence of TAAs is estimated to be at least 5.3 per 100,000 people per year, while AADs affect around 3 to 4 people per 100,000 person-years [1] [2]. In addition, thoracic aortic surgery already represents a significant proportion of cardiac activity, corresponding, for example, to 8% of the total volume of cardiac surgery in the United States [3].
In sub-Saharan Africa, epidemiological data on these diseases remain limited. Restricted access to specialist care, lack of appropriate infrastructure, scarcity of cardiac surgeons and lack of early diagnosis often lead to lethal complications [4] [5]. In these regions, the true prevalence of TAA and AAD remains unknown, but between 1990 and 2019, morbidity and mortality linked to aortic disease rose by 67% worldwide, and by up to 150.55% in certain low- and middle-income countries [6]. In Sub‑Saharan Africa, the hospital frequency of aortic dissection has been reported to vary between 0.24% and 0.6%, suggesting an emerging burden in the region [7] [8].
Historically, West Africa saw its first open-heart surgeries in the 1970s, with notable milestones including January 1974 in Enugu (Nigeria) and March 1978 in Abidjan (Côte d’Ivoire) [9]. In contrast, Benin’s access to ascending aorta surgery has long been constrained by inadequate technical infrastructure and limited opportunities for medical evacuation to specialized centers. Recognizing these challenges, Benin introduced cardiac surgery in March 2021 with the aim of improving access to advanced cardiovascular care. This article reports the short-term results, over a 90-day period, of the first cases of ascending aorta pathology managed surgically in Benin.
2. Methods
This prospective, descriptive study was conducted from March 2021 to October 2024 at the Hubert Koutoukou Maga National University Hospital Center (CNHU-HKM). All patients who underwent surgical repair for an ascending aortic aneurysm or type A aortic dissection during the study period were included. The majority of patients were referred from other healthcare facilities or physicians after the discovery of ascending aortic disease. The diagnosis was confirmed by imaging (CT angiography and/or transthoracic echocardiography) and validated by a multidisciplinary consensus involving cardiac surgeons, cardiologists, and anesthesiologists. Free and informed consent was obtained from each patient and their family following a detailed explanation of the procedure’s risks and benefits. We collected sociodemographic, clinical, and surgical data, as well as postoperative outcomes. Data were collected and analysed using kobocollect. For the descriptive analysis, the quantitative variables were described in the form of mean ± standard deviation or median with the interquartile range after verification of normality using the Shapiro-Wilk test. Qualitative variables were described as proportions or frequencies. The various authorisations from the Hubert Koutoukou Maga National University Hospital Center were received.
3. Results
3.1. Preoperative Data
Fifteen patients (15) underwent ascending aortic surgery out of 128 open-heart surgeries performed during the study period, representing a frequency of 11.7%. Twelve patients (80%) were male, with a sex ratio of 4:1. The mean age was 50.4 ± 7.4 years (range 29 to 62 years). The mean body mass index was 22.7 ± 4.9 kg/m2 with a mean body surface area of 1.8 ± 0.1 m2. Dyspnea was present in 66.7% of patients. In 14 patients (93.3%), the chest X-ray revealed mediastinal widening. The electrocardiogram (ECG) showed left ventricular hypertrophy in 93.3%. Preoperative risk factors included hypertension in 10 patients (66.7%), a rheumatic etiology in 3 patients (20%), Marfan syndrome in 1 patient (6.7%), and Laubry-Pezzi syndrome in 1 patient (6.7%) (Table 1).
A total of 11 ascending aortic aneurysms (73.3%) and 4 chronic type A aortic dissections (26.7%) were noted. The mean left ventricular ejection fraction (LVEF) was 54.3% ± 9.9% with extremes of 35 and 68%. Mean left ventricular end-diastolic diameter (LVEDD) was 68.3 ± 10.4 mm with extremes ranging from 52 to 86 mm. Severe aortic regurgitation was noted in 13 patients (93.3%). The mean diameter of the ascending aorta was 55 ±12.7 mm, with extremes of 35 and 106 mm (Table 1).
Table 1. Preoperative data of patients who underwent ascending aortic surgery in Benin (N = 15).
|
Values |
Gender |
|
Male, n (%) |
12 (80) |
Female, n (%) |
3 (20) |
Average age, mean ± SD (range) |
50.4 ± 7.4 years (29 - 62) |
Average BMI, mean ± SD (range) |
22.7 ± 4.9 kg/m2 |
Average body surface area, mean ± SD (range) |
1.8± 0.1 m2 |
Symptoms |
|
Dyspnea, n (%) |
10 (66.7) |
Stage II, n (%) |
5 (33.3) |
Stage III, n (%) |
2 (13.3) |
Stage IV, n (%) |
3 (20) |
Chest pain, n (%) |
8 (53.3) |
Radiographic signs |
|
Mediastinal widening, n (%) |
14 (93.3) |
Electrocardiographic signs |
|
Left ventricular hypertrophy, n (%) |
14 (93.3) |
Left atrial hypertrophy, n (%) |
6 (40) |
First-Degree Atrioventricular Block, n (%) |
2 (13.3) |
Atrial fibrillation, n (%) |
1 (6.7) |
Etiology |
|
Hypertension, n (%) |
10 (66.7) |
Rheumatic, n (%) |
3 (20) |
Marfan’s disease, n (%) |
1 (6.7) |
Laubry-Pezzi syndrome, n (%) |
1 (6.7) |
Average LVEF, mean ± SD (range) |
54.3 ± 9.9% (35 - 68) |
Average diameter of the aorta, mean ± SD (range) |
55 ± 12.7 mm (35 - 106) |
Average LVEDD, mean ± SD (range) |
68.3 ± 10.4 mm (52 - 86) |
Associated valve disease |
|
Aortic regurgitation, n (%) |
13 (86.7%) |
Mitral regurgitation, n (%) |
1 (6.7%) |
3.2. Operating Data
The surgical approach was a total median sternotomy in all cases. Cannulation was aorto-bicaval in 10 patients, aorto-atriocaval in 4, and brachiocephalic artery–atriocaval in 1. Normothermic blood cardioplegia was used in all patients. The mean cardiopulmonary bypass time was 124.5 ± 31.2 minutes, and the mean cross-clamping time was 96.5 ± 14.4 minutes. Hypothermia with circulatory arrest and cerebral perfusion was performed in three patients (20%) using selective antegrade cerebral perfusion through the carotid arteries.
Eight (8) patients underwent a Bentall procedure with mechanical valve (Figure 1 and Figure 2), while six (06) patients underwent a supracoronary ascending aortic replacement (SCAAR) with aortic valve (AV) replacement with mechanical prosthesis. Only one (01) Tirone David procedure was performed. Additionally, two patients underwent a hemiarch replacement of the aorta during the procedure. The associated procedures are listed in Table 2.
3.3. Surgical Outcomes
During the first 90 days post-operatively, functional improvement was observed in all patients (NYHA stage I-II). Postoperative complications included two cases of third-degree atrioventricular block, all of which required pacemaker implantation, as well as one stroke, one instance of acute kidney injury not requiring dialysis, and one reoperation for bleeding. One death occurred in the context of SARS-CoV-2 infection, corresponding to a hospital mortality rate of 6.6% (Table 2).
Figure 1. Transthoracic ultrasound image showing an aneurysm of the ascending aorta.
(a) (b) (c) (d)
Figure 2. Operative view of Bentall procedure with mechanical valve. (a) Operative view of an ascending aortic aneurysm; (b) Attaching the valved tube to the aortic annulus; (c) Reimplantation of coronary arteries with a dacron prosthetic tube; (d) Result of Bentall procedure.
Table 2. Operative and outcome data for patients who underwent ascending aortic surgery in Benin (N = 15).
|
Values |
Cardioplegia |
|
Blood, n (%) |
15 (100%) |
Central temperature |
|
Normothermia, n (%) |
15 (100) |
Cardiopulmonary bypass time, mean ± SD (range) |
124.5 ± 31.2 [86 - 207] |
Cross-Clamping time, mean ± SD (range) |
96.5 ± 14.4 [70 - 127] |
Canulation |
|
Aorto-atriocaval, n (%) |
10 (66.7) |
Aorto-bicaval, n (%) |
4 (26.7) |
Brachiocephalic artery-atriocaval, n (%) |
1 (6.7) |
Hypothermia + Circulatory arrest + Cerebral perfusion (temperature-duration) |
|
30˚C - 1 min 30 s, n (%) |
1 (6.7) |
18˚C - 32 min, n (%) |
1 (6.7) |
20˚C - 37 min, n (%) |
1 (6.7) |
Surgical procedure performed |
|
Bentall procedure with mechanical valve, n (%) |
7 (46.6) |
SCAAR with AV replacement, n (%) |
5 (33.3) |
Tirone-David, n (%) |
1 (6.7) |
Bentall procedure with mechanical valve + Hemiarch replacement, n(%) |
1 (6.7) |
SCAAR with AV replacement + Hemiarch replacement, n (%) |
1 (6.7) |
Associated surgical procedure |
|
Tricuspid valve repair, n (%) |
3 (20.0) |
Mitral valve repair, n (%) |
1 (6.7) |
Ventricular septal defect closure, n (%) |
1 (6.7) |
Aortic graft diameter |
|
30 mm dacron aortic graft, n (%) |
12 (80.0) |
32 mm dacron aortic graft, n (%) |
2 (13.3) |
28 mm dacron aortic graft, n (%) |
1 (6.7) |
Average post-operative LVEF, mean ± SD (range) |
48.1 ± 14.1 (15 - 62) |
Post-operative complications |
|
Third-Degree Atrioventricular Block, n (%) |
2 (13.3) |
Stroke, n (%) |
1 (6.7) |
Acute renal failure without replacement therapy, n (%) |
1 (6.7) |
Bleeding, n (%) |
1 (6.7) |
90-day mortality |
1 (6.7%) |
Median time to death (days) |
3 |
4. Discussion
The frequency of ascending aorta surgery was 11.5% compared with 2% reported by Majdoub et al. in Morocco [10]. This type of surgery accounts for a considerable proportion of cardiac surgery in developed countries, notably 8% in the United States [3]. This low proportion in sub-Saharan Africa reflects persistent difficulties in diagnosing and treating these diseases rather than any real rarity. Indeed, recent epidemiological and autopsy studies highlighting an increase in mortality from aortic aneurysms and dissections in sub-Saharan Africa reinforce this impression. The front-line involvement of nurses and General Practitioners, who are prone to misinterpretation, and the lack of local resources for advanced cardiovascular imaging, which is difficult to access, could also explain this observation [11] [12].
The mean age of our cohort is in line with the literature, ranging from 43.8 to 69 years [13]-[15]. Male predominance is the rule in several series [13] [16] [17]. Similarly, hypertension emerges as the main etiology, in line with the findings of previous studies conducted in the sub-region [14]. Other studies have also highlighted a rheumatic etiology in their series [10].
The most frequently operated aortic pathology is ascending aortic aneurysm (73.3%). In the literature, a similar observation is found with a rate of 64.2% [14]. This could be explained by the high pre-hospital mortality of acute aortic lesions, which justifies the preponderance of chronic lesions.
The mean times for cardiopulmonary bypass (124 minutes) and cross-clamping (96 minutes) are within the ranges reported in other series, varying respectively between 115 and 179.7 minutes and between 78.5 and 120.7 minutes [17] [18]. Bentall procedure was the most frequently performed procedure, accounting for 53% of cases in our study. Authors in the sub-region have reported a higher preponderance of this procedure, ranging from 78% to 80% [10] [14]. Similar to many centers in our region, we favor the Bentall procedure for the majority of ascending aortic surgeries, particularly due to the prevalent valvular lesions and the fact that this technique generally requires less specialized valve-repair expertise.
Hospital mortality was 6.6%, which is lower than most series in the sub-region (9.2% to 20%) [10] [14] [18]. One key factor may be the lower proportion of acute aortic dissections, which often account for the majority of deaths in those cohorts. We therefore recommend focusing on prevention and early diagnosis (systematic hypertension screening, training of primary care practitioners, and enhancing imaging access), improving the rapidity of management for type A acute aortic dissections, further expanding cardiac surgery infrastructure, and creating a national or regional registry to standardize care and improve overall quality in aortic surgery.
Finally, the inherent limitations of our study are similar to those encountered in regional research on ascending aortic surgery, in particular the small number of participants [10] [14].
5. Conclusion
In Benin, the main indications for surgery on the ascending aorta are aneurysms and chronic type A aortic dissections. Bentall procedure remains the most commonly used surgical method for these procedures. Short-term results are generally satisfactory. This demonstrates the efficacy and viability of this therapeutic approach in the Beninese context. These initial data suggest that it would be worthwhile continuing to develop surgical capabilities. This will help optimise results and ascending aorta surgery in sub-Saharan Africa.