RESEARCH

 

A cross-sectional study of patients with prosthetic mitral valves at a tertiary centre in Johannesburg, South Africa

 

 

P Sumaraj^I; R Meel^II

^IMB ChB, FCP (SA); Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand and Life Bedford Gardens Hospital, Johannesburg, South Africa
^IICert Cardiology (SA), PhD; Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand and Sandton Mediclinic, Johannesburg, South Africa

Correspondence

 

 

---

ABSTRACT

BACKGROUND. There is a high incidence of rheumatic valvular heart disease involving the mitral valve in Soweto, Johannesburg. Many of these patients go on to have mitral valve replacement (MVR). Data regarding clinical and echocardiographic characteristics of patients with prosthetic mitral valves are scarce in South Africa.
OBJECTIVE. To document the clinical and echocardiographic profiles of contemporary patients with MVR.
METHODS. Clinical, electrocardiographic and echocardiographic data in these patients were collected prospectively from March 2020 to August 2021 at Chris Hani Baragwanath Academic Hospital prosthetic valve clinic.
RESULTS. The study included 186 participants with a median (interquartile range (IQR)) age of 52 (41 - 60) years. Of these, 96% were of black African ethnicity (79% female). The median (IQR) body mass index (BMI) among participants was 27 (23.5 - 30.4) kg/m², with 29% of participants classified as obese (BMI >30 kg/m²). Eighty-two percent of patients had New York Heart Association class 1 dyspnoea. The most common complications were atrial fibrillation (AF, 39%), heart failure (HF, 25%) and stroke (13%). There were two cases of previously documented prosthetic valve thrombosis, two cases of prosthetic valve endocarditis, two of paravalvular regurgitation and one with structural valve deterioration. Seventy percent of patients had subtherapeutic international normalised ratios (INRs), with a median (IQR) INR of 2.55 (2.03 - 2.92). Forty-seven percent of patients had a left ventricular ejection fraction (EF) of <40%. Seventy-four percent of participants were on some combination of guideline-directed medical therapy for HF with reduced EF, although only 12% were on at least three medications. Pulmonary hypertension was present in 37% of patients, with a median (IQR) pulmonary artery systolic pressure of 28.5 (17 - 41) mmHg. Tricuspid annuloplasty ring was noted in a minority (12 patients).
CONCLUSION. The contemporary patients with MVR were middle-aged obese females with significant AF burden, residual left ventricular dysfunction that was suboptimally managed, and subtherapeutic INR.

Keywords: cardiology, valvular heart disease, prosthetic heart valves, heart failure

---

 

 

In the peri-urban setting of Soweto, Johannesburg, South Africa (SA),valvular heart disease is prevalent.^[1] Rheumatic heart disease (RHD) is a common aetiology in this setting, with a recent estimated incidence of 23.5 cases per 100 000 population per year.^[1] Previous studies show that ~36% of all newly diagnosed valvular lesions are due to RHD, with 89% of cases involving the mitral valve.^[1] Additionally, patients with mitral valve disease in this setting tend to be older and have morphological characteristics that favour replacement over repair.^[2] There is also an increasing incidence of infective endocarditis among younger patients in urban settings in SA, and up to 50% of these cases require surgical intervention.^[2-5] In addition, with an ongoing epidemiological transition towards more diseases of lifestyle and elderly age, it can be expected that there will be more cases of degenerative valvular disease.^[6]

Despite recent improvements in technology, medical therapy and surgical techniques, many patients still have ongoing medical issues after valve replacement surgery (an entity termed 'prosthetic valve disease').^[7,8] The complications of prosthetic valve disease include paravalvular regurgitation, structural valvular deterioration, pannus formation, endocarditis, thrombosis and embolism, anticoagulation-related haemorrhage and haemolysis. Thus these are complex patients who require adequate monitoring and appropriate therapy. In this way, complications can be prevented, detected early and managed timeously.^[7]

Developed nations have large databases describing their prosthetic valve populations - the primary aetiology being degenerative.^[8,9] In comparison, there are minimal data in the SA setting. We therefore sought to systematically document the clinical and echocardiographic outcomes of these patients in our setting.

 

Objectives

To document the clinical and echocardiographic profiles and to evaluate the types of morbidity of patients with prosthetic mitral valve replacement (MVR).

 

Methods

This was a cross-sectional descriptive study of patients with prosthetic mitral valves at Chris Hani Baragwanath Academic Hospital. It was conducted from March 2020 to August 2021 (while the initial study period was planned from March 2020 to August 2020, the coronavirus pandemic delayed data collection). The investigator collected demographic, clinical and electrocardiographic data, while the cardiac technologist collected echocardiographic data (all part of the routine care of patients). This was done once-off and with the informed consent of the participants.

Each patient had their vital signs (including blood pressure, pulse rate, respiratory rate and temperature), weight and height recorded. This was followed by a clinical interview by the primary investigator, specifically inquiring about the history of their valve replacement, indications, complications, functional status and associated comorbidities. Finally, this information was supplemented with data from their available clinical records (including their international normalised ratio (INR) clinic records).

Transthoracic echocardiography was then performed on all patients in the study using the Philips EPIQ 7C iE33 (Philips, the Netherlands), and images were obtained according to standard protocol. Measurements were done according to the American Society of Echocardiography chamber quantification guidelines of 2015,^[10] as well as the European Society of Cardiology and American Heart Association guidelines for managing patients with valvular heart disease,^[11,12] and were indexed to body surface area. In all cases, assistance from an experienced cardiologist was sought.

The biochemical profiles of patients were obtained from recent routine measurements (such as full blood counts, urea, creatinine, electrolytes, lactate dehydrogenase and international normalised ratios (INRs)).

We recruited 186 patients to obtain a statistically significant result. Inclusion criteria were age >18 years and patients with prosthetic MVR (with or without other prosthetic valves). Exclusion criteria were refusal to participate and isolated non-mitral valve replacement.

Ethical approval was obtained from the University of the Witwatersrand Human Research Ethics Committee (ref. no. M200905). The study was performed per the World Medical Association Declaration of Helsinki ethical principles for medical research involving human subjects.

 

Statistical analysis

The data analysis was done using descriptive statistics, where categorical data were expressed as percentages, and continuous variables were expressed as either mean or median (standard deviation (SD)) or interquartile range (IQR). Continuous variables were compared using Student's f-test, and data with non-parametric distribution were assessed by Fisher's exact test. A p-value <0.05 was considered statistically significant. Pearson's correlation was used to correlate variables.

Poisson regression with robust error variance was used to determine the strength and direction of association between demographic, clinical, electrocardiographic and echocardiographic findings of patients who had MVR with the left ventricular ejection fraction (LVEF) <40%. Variables that had p-values <0.2 in univariable analysis were eligible for inclusion in an initial multivariable model, but were eliminated in a stepwise backwards approach until eight variables remained in the model. Prevalence rate ratios associated with the variables were reported with 95% confidence intervals (CIs).

 

Results

Ninety-six percent of participants were of black African descent (Table 1). The study population had a median (IQR) age of 52 (40 - 61) years, and was predominantly of female biological sex (79%). Most patients were overweight, with a median body mass index (BMI) of 26.6 kg/m², while 29% were obese, with a BMI >30 kg/m². The most common comorbidities noted were hypertension (36%) and diabetes mellitus (8%). Most patients were normotensive, not tachycardic and not in overt heart failure (HF) during assessment. Approximately two-thirds of patients had only had surgical intervention and replacement of the mitral valve (66%); the remaining patients had mitral valve and a combination of aortic and/or tricuspid valve surgery. In terms of functional status, 82% of patients were classified as New York Heart Association (NYHA) class I dyspnoea. The rest (17.2%) were classified as NYHA class II dyspnoea. As shown in Fig. 1, most patients in this study were operated on after the year 2000.

Thirty-nine percent of patients were in persistent/permanent atrial fibrillation (AF). HF admissions had occurred in 25% of all patients, and cerebrovascular accidents (CVAs) occurred in 13% of all patients. However, the aetiology of these (embolic v. haemorrhagic or other) was not reliably documented. There were two cases each of previously documented prosthetic valve endocarditis, thrombosis and paravalvular regurgitation, and only one of structural valve deterioration. This is further illustrated in Fig. 2.

Fig. 3 shows the number of patients on guideline-directed medical therapy for HF, with 74% on some combination of treatments.

Biochemical analysis (Table 2) revealed that 65% of patients had normal haemoglobin values at the last measurement, although only 109 in total had this measurement available. Of note, 17% of patients had anaemia of moderate to severe classification, as per World Health Organization definitions.^[13] Renal function was normal in almost all patients (n=110; 86%) with these measurements available. Regarding anticoagulation, the INRs for patients on long-term warfarin therapy were striking, with 70% of patients having <70% of their measurements in a suitable therapeutic range, i.e. between 2.5 and 3.5. The median (IQR) INR among all participants was 2.55 (2.03 - 2.92). Approximately 10% of participants were HIV positive, and all these patients were on antiretroviral therapy (ART), with 14 of them virally suppressed. Three HIV-positive patients did not have any accessible record of recent CD4 counts or viral load.

 

Echocardiographic features

Approximately 50% of patients in this study had left ventricular systolic dysfunction, defined as an ejection fraction (EF) <40%^[14] (Table 3). Most patients had evidence of possible elevated left ventricular filling pressures, as evidenced by a median (IQR) lateral E/e' (ratio of early diastolic filling to mitral annular velocity) of 17.4 (13.6 - 21.7) and a median (IQR) medial E/e' of 22.6 (16.4 - 28.8). Interestingly, only 18% of participants reported a NYHA functional class of II or higher. This could be due to the subjective nature of symptom reporting and the presence of mitral valve prostheses, which may offset mitral annular tissue Doppler measurements. Most patients (71%) had significant left atrial enlargement, with a median indexed left atrial volume of 44.4 mL/m². The median right ventricular (RV) basal diameter was 42 mm, while the median RV S' (RV systolic wave velocity) was 8.7 cm/s, indicating that most patients had enlarged and dysfunctional right ventricles. Pulmonary hypertension was present in 36.6% of patients, with a median (IQR) pulmonary artery systolic pressure of 28.5 (17 - 41) mmHg. A tricuspid annuloplasty ring was evident in 12 patients. Ninety-five percent of patients had metallic valves, and all of these were bileaflet in nature. The median mean pressure gradient across the mitral valve was 3.5 mmHg. The median Doppler velocity index was 1.77, with an upper quartile of 2.36. These findings indicate that most patients did not exhibit any features of possible stenosis. Paravalvular regurgitation was evident in only two patients. No cases of endocarditis, structural valve deterioration, or pannus formation were found during the echocardiographic assessments. Approximately 10% of patients had a pericardial effusion, most of which were mild. Three percent of patients had a thickened pericardium.

 

 

The characteristics of patients with reduced v. preserved LVEF are compared in Table 4. Of note, patients with a reduced LVEF tended to have higher creatinine and more AF. In both univariate and multivariate analyses, the presence of AF was shown to be a strong predictor of poor LVEF, while renal function did not demonstrate a strong association.

 

Discussion

Our study attempts to bridge the gap in knowledge regarding outcomes of patients with mechanical MVRs in the SA setting.

The patient population was predominantly middle-aged, black African, female and overweight or obese - this underscores the expected epidemiological shift in our setting.^[6] Further, a significant proportion of patients had comorbidities, such as hypertension and diabetes mellitus. These findings are similar to those of a previous study conducted in a preoperative population with mitral valve disease at Chris Hani Baragwanath Academic Hospital, Johannesburg,^[15] although there was a higher incidence of comorbidities, especially hypertension (36% v. 30%) and diabetes mellitus (8% v. 4%) in our study, which may reflect changing socioeconomic and lifestyle factors. A similar, though perioperative, study investigating the perioperative outcomes of valve replacement surgeries at another centre in Johannesburg documented similar rates of comorbidities.^[16] However, studies in high-income settings showed significantly higher rates of comorbid disease, with 50 - 73% of patients having hypertension and 35% with dyslipidaemia, for example.^[17] This is likely explained by the fact that patients undergoing valve replacement in high-income settings are generally older, with an average age of 66 years in one study.^[17]

There was a statistically significant association between female sex and isolated MVR, with 84% of all isolated MVR surgeries occurring in female patients (p=0.013). Previous studies have noted the higher incidence of mitral valve disease in female patients, which may account for this finding.^[18-20] Interestingly, male patients were as likely to have isolated MVR (20 patients) v. multiple valve replacement (19 patients). Female patients were more likely to be obese, with almost all patients (94%) with a BMI >30 kg/m² being female (p<0.001). This association also extended to the incidence of hypertension (p=0.009) and diabetes (p=0.037). Multiple studies in the African and sub-Saharan setting have shown a higher incidence of metabolic syndrome and its associated conditions (including obesity and hypertension) among female patients of black African ethnicity.^[21] Obese patients were also noted to be more likely to have had an isolated MVR (likely owing to most of them being of female sex), therefore with a higher BMI on average in this study, although the effects of obesity itself cannot be ruled out, which is a potential area for future study. More patients were HIV positive among those operated on after the year 2000, likely due to the introduction of combined ART for these patients during that time period, as well as a high incidence of HIV during that period.^[22]

The available data gave the impression that the majority of valve replacements took place post 2000. We cannot conclude whether this finding is a result of patients lost to follow-up, death, or simply fewer patients operated on prior to 2000. It may be due to increasing incidence of chronic RHD and related complications, improved screening techniques for RHD, or improved access to medical and cardiology services in the last two decades; however, a lack of data makes it difficult to draw a reliable conclusion. Previous studies have shown an increasing prevalence of RHD (and sadly increasing mortality), which may account at least partially for the greater numbers of valve replacements in recent years.^[23,24

Most patients had subtherapeutic INRs and tended towards the lower end of the recommended range for patients with mechanical mitral valves. This is probably multifactorial, involving inadequate monitoring and adjustment of warfarin dosage, lack of adequate education regarding long-term vitamin K antagonist therapy (patients are given information leaflets, but these are only available in English) and socioeconomic factors.^[23] This finding is consistent with numerous other studies in SA and other low- to middle-income countries,^[25-27] but at odds with the findings at another academic hospital in Johannesburg.^[28] Many patients (24 in this study) had had a CVA of undefined aetiology, and some had also had re-do surgery with an undocumented indication. It is reasonable to assume some contribution from chronically subtherapeutic INRs, as this commonly contributes to re-operation in the SA setting,^[29] and CVAs in patients with prosthetic valves are often attributable to embolic disease.

Nearly 40% of patients were still in AF years after their MVR. None of the participants had evidence of patient-prosthesis mismatch or prosthetic valve stenosis, ruling out these potential reasons for the persistence of AF. The high incidence of AF may reflect a delay in time to surgery, with further progression of disease and consequent atrial remodelling, or may be indicative of late detection of disease and index presentation in a more advanced stage. Also, only four patients had maze procedures done during their valve replacement, which may explain the high incidence of persistent AF in these patients. It has previously been shown that the performance of a maze procedure in patients being operated on for valvular RHD reduces the incidence of both AF and thromboembolic complications postoperatively.^[30]

A minority of patients (n=12; 6%) had tricuspid annuloplasty evident during their assessment. This is somewhat surprising given the frequency of tricuspid annular dilatation noted (median (IQR) tricuspid annular diameter of 38 (35 - 43) mm, and 40% >40 mm). Current guidelines suggest repairing the annulus in the presence of even mild to moderate secondary tricuspid regurgitation (TR), should the annulus measure >40 mm, or in the presence of features of right HF.^[31] The benefits of such repair are evident, improving reverse remodelling of the right ventricle and functional status without much associated risk.^[31] This is important as the risk of reoperation for TR after left-sided surgery is particularly aggravated by the entity of restriction-dilatation syndrome, originally described by Barlow.^[32] The restriction-dilatation syndrome refers to worsening RV systolic function, from TR, causing diastolic shifting of the interventricular septum into the left ventricle (LV), thereby increasing LV filling pressures and further worsening the TR - this is aggravated by the presence of adhesions from previous left thoracotomy.^[33]

Approximately half (47%) of all patients had biventricular dysfunction. This likely reflects the previous disease process and possible delay in presentation or definitive treatment, i.e. residual biventricular dysfunction. Other factors that may explain or contribute include comorbidities, such as HIV, obesity, hypertension, ischaemic heart disease and diabetes mellitus. The presence of AF was strongly associated with poor LV function. This may be explained in two ways: firstly, it may lend further credence to the possibility of a delay in presentation and treatment, thereby worsening both atrial and ventricular remodelling; another possibility is AF directly worsening LV function or preventing reverse remodelling (tachyarrhythmia-induced HF). A study by Suri et al.^[34] lends credence to this hypothesis, showing a greater drop in postoperative EF in patients with AF undergoing mitral valve surgery. Many patients also had significant LV diastolic dysfunction with elevated filling pressures, which is likely due to previous disease processes, delay in time to treatment and possibly the presence of comorbidities such as hypertension, diabetes mellitus and obesity.

Interestingly, there were only two documented cases of prosthetic valve endocarditis. This is far fewer than in another study conducted at a hospital in Cape Town, SA.^[35] There are two possible reasons for this: (i) prosthetic valve endocarditis carries a high mortality, therefore survivorship bias may play a role; and (ii) the relative lack of robust documentation and/or the absence of an electronic health record result in a loss of the relevant data.

Overall, our study suggests that it would be beneficial to perform MVR sooner, that maze procedures should be considered more often in patients with concomitant AF and that tricuspid annuloplasty must be offered to all patients undergoing MVR, as per standard guideline recommendations, to prevent late tricuspid regurgitation.^[11] Consideration of bioprosthetic valve replacement as per guideline indications will help relieve the burden of complications related to the use of warfarin. Continued education of the public regarding RHD and related complications will result in earlier presentation and better long-term postoperative outcomes. Education regarding long-term vitamin K antagonist therapy (for both clinicians and patients) and stricter monitoring of INR should also be considered. Future studies could focus on the impact of such potential interventions, and examine the ever-changing demographic profile of our patient population. An emphasis should also be placed on the initiation and titration of guideline-directed medical therapy for HF, especially given the significant discrepancy between the number of patients with reduced EFs (almost half of the cohort) and the number of patients on at least three medications (only 12% in this study).

The strengths of this study include the significant numbers recruited, the prospective nature of data collection and the wide array of parameters examined, particularly when compared with similar studies in our setting. Weaknesses include once-off data collection, missing information in patient files and a lack of pre- and postoperative data (such as LVEF, tricuspid annular measurements and the rate of AF), including the number of MVR operations performed over time.

 

Conclusion

Contemporary patients with MVR were obese, middle-aged, black African females with associated comorbidities, such as hypertension and diabetes mellitus. A significant portion of patients had residual biventricular dysfunction, which was strongly correlated with the presence of AF. The most common complications were AF, HF and inadequate warfarinisation, followed by valve-specific complications. The majority of patients with HF were not on optimal guideline-directed medical therapy. These findings underline the need for more ready access to timely valve replacement, improved management of anticoagulation therapy and optimisation of guideline-directed medical therapy for HF in these patients.

Data availability. The authors will share raw data upon reasonable request from readers.

Declaration. None.

Acknowledgements. The authors would like to express their gratitude to the patients for participating in this research, and to the staff in the Chris Hani Baragwanath Academic Hospital cardiology clinic.

Author contributions. Concept and design of the study: RM, PS. Acquisition of data: PS, RM. Drafting the manuscript: PS, RM. Revising the manuscript for important intellectual content: RM, PS. Approval of the manuscript to be published: RM, PS.

Funding. None.

Conflicts of interest. None.

 

References

1. Sliwa K, Carrington M, Mayosi BM, Zigiriadis E, Mvungi R, Stewart S. Incidence and characteristics of newly diagnosed rheumatic heart disease in urban African adults: Insights from the heart of Soweto study. Euro Heart J 2010;31(6):719-727. https://doi.org/10.1093/eurheartj/ehp530        [ Links ]

2. Meel R, Peters F, Libhaber E, Essop MR. The changing spectrum of rheumatic mitral regurgitation in Soweto, South Africa. Cardiovascular J Africa 2017;28(4):215-220. https://doi.org/10.5830/CVJA-2016-086        [ Links ]

3. Meel R, Essop MR. Striking increase in the incidence of infective endocarditis associated with recreational drug abuse in urban South Africa. S Afr Med J 2018;108(7):585-589. https://doi.org/10.7196/SAMJ.2018.v108i7.13007        [ Links ]

4. Pecoraro AJ, Doubell AF. Infective endocarditis in South Africa. Cardiovasc Diagn Ther 2020;10(2):252-261. https://doi.org/10.21037/cdt2019.06.03        [ Links ]

5. De Villiers MC, Viljoen CA, Manning K, et al. The changing landscape of infective endocarditis in South Africa. S Afr Med J 2019;109(8):592-596. https://doi.org/10.7196/SAMJ.2019.v109i8.13888        [ Links ]

6. Moloi AH, Watkins D, Engel ME, Mall S, Zühlke L. Epidemiology, health systems and stakeholders in rheumatic heart disease in Africa: A systematic review protocol. BMJ Open 2016;6(5):e011266. https://doi.org/10.1136/bmjopen-2016-011266        [ Links ]

7. Pibarot P, Dumesnil JG. Prosthetic heart valves. Circulation 2009;119(7):1034-1048. https://doi.org/10.1161/CIRCULATIONAHA.108.778886        [ Links ]

8. Durko AP, Head SJ, Pibarot P, et al. Characteristics of surgical prosthetic heart valves and problems around labelling: A document from the European Association for Cardio-Thoracic Surgery (EACTS) -The Society of Thoracic Surgeons (STS) - American Association for Thoracic Surgery (AATS) Valve Labelling Task Force. Euro J Cardio-Thoracic Surg 2019;55(6):1025-1036. https://doi.org/10.1093/ejcts/ezz034        [ Links ]

9. Garver BA, Kaczmarek RG, Silverman BG, Gross TP, Hamilton PM. The epidemiology of prosthetic heart valves in the United States. Tex Heart Inst J 1995;22:86-91.         [ Links ]

10. Zoghbi WA, Chambers JB, Dumesnil JG, et al. Recommendations for evaluation of prosthetic valves with echocardiography and Doppler ultrasound. J Am Soc Echocardiography 2009;22(9):975-1014. https://doi.org/10.1016/j.echo.2009.07.013        [ Links ]

11. Vahanian A, Beyersdorf F, Praz F, et al. 2021 ESC/EACTS guidelines for the management of valvular heart disease. Euro Heart J 2021;43(7):561-632.         [ Links ]

12. Otto CM, Nishimura RA, Bonow RO, et al. 2020 ACC/AHA guideline for the management of patients with valvular heart disease: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation 2021;143(5):e35-e71. https://doi.org/10.1161/CIR.0000000000000923        [ Links ]

13. World Health Organization. Haemoglobin concentrations for the diagnosis of anaemia and assessment of severity. Geneva: WHO, 2011. http://www.who.int/vmnis/indicators/haemoglobin (accessed 15 February 2023).         [ Links ]

14. McDonagh TA, Metra M, Adamo M, et al. 2023 Focused update of the 2021 ESC guidelines for the diagnosis and treatment of acute and chronic heart failure. Euro Heart J 2023;44(37):3631-3634. https://doi.org/10/1093/eurheartj/ehad195        [ Links ]

15. Banderker E, Roozen G, Tsitsi M, Meel R. A cross-sectional study of the spectrum, aetiology and clinical characteristics of adult mitral valve disease at Chris Hani Baragwanath Academic Hospital. Cardiovasc J Africa 2023;34:1-7. https://doi.org/10.5830/cvja-2023-009        [ Links ]

16. Tabane TMM, Leonard T, Kleyenstuber T. Peri-operative outcomes of mitral valve surgery at Charlotte Maxeke Johannesburg Academic Hospital. SA Heart 2021;18(2):118-125. https://doi.org/10.24170/18-2-4884        [ Links ]

17. Bonnet V, Boisselier C, Saplacan V, et al. The role of age and comorbidities in postoperative outcome of mitral valve repair. Medicine 2016;95(25):e3938. https://doi.org/10.1097/MD.0000000000003938        [ Links ]

18. Movahed MR, Ahmadi-Kashani M, Kasravi B, Saito Y. Increased prevalence of mitral stenosis in women. J Am Soc Echocardiography 2006;19(7):911-913. https://doi.org/10.1016/j.echo.2006.01.017        [ Links ]

19. Pasca I, Dang P, Tyagi G, Pai RG. Survival in patients with degenerative mitral stenosis: Results from a large retrospective cohort study. J Am Soc Echocardiography 2016;29(5):461-469. https://doi.org/10.1016/j.echo.2015.12.012        [ Links ]

20. Mantovani F, Clavel M, Michelena HI, Suri RM, Schaff HV, Enríquez-Sarano M. Comprehensive imaging in women with organic mitral regurgitation. JACC Cardiovasc Imaging 2016;9(4):388-396. https://doi.org/10.1016/j.jcmg.2016.02.017        [ Links ]

21. Gradidge PJL, Crowther NJ. Review: Metabolic syndrome in black South African women. Ethnicity Dis 2017;27(2):189. https://doi.org/10.18865/ed.27.2.189        [ Links ]

22. South African National AIDS Council. HIV/AIDS and STD strategic plan for South Africa 2000 - 2005. Pretoria: National Department of Health, 2000. https://sanac.org.za/wp-content/uploads/2019/02/NSP-2000-2005.pdf (accessed 25 May 2025).         [ Links ]

23. Zilla P, Human P, Pennel T. Mechanical valve replacement for patients with rheumatic heart disease: The reality of INR control in Africa and beyond. Front Cardiovasc Med 2024;11. https://doi.org/10.3389/fcvm.2024.1347838        [ Links ]

24. Roth GA, Mensah GA, Johnson CO, et al. Global burden of cardiovascular diseases and risk factors, 1990 - 2019: Update from the GBD 2019 study. J Am Coll Cardiol 2022;76(25):2982-3021. https://doi.org/10.1016/j.jacc.2020.11.010        [ Links ]

25. Ntlokotsi S, Moshesh MF, Mntla P, Towobola OA, Mogale M. Optimum INR intensity and therapeutic INR control in patients with mechanical heart valve prosthesis on warfarin oral anticoagulation at Dr George Mukhari academic hospital: A three-year retrospective study. S Afr Fam Pract 2018;60(6):192-196. https://doi.org/10.4102/safp.v60i6.4927        [ Links ]

26. Alphonsa A, Sharma KK, Sharma G, Bhatia R. Knowledge regarding oral anticoagulation therapy among patients with stroke and those at high risk of thromboembolic events. J Stroke Cerebrovasc Dis 2015;24(3):668-672. https://doi.org/10.1016/j.jstrokecerebrovasdis.2014.11.007        [ Links ]

27. Oldgren J, Healey JS, Ezekowitz M, et al. Variations in cause and management of atrial fibrillation in a prospective registry of 15 400 emergency department patients in 46 countries: The RE-LY Atrial Fibrillation Registry. Circulation 2014;129(15):1568-1576. https://doi.org/10.1161/CIRCULATIONAHA.113.005451        [ Links ]

28. Schapkaitz E, Jacobson BF, Becker P, Conway G. Thrombo-embolic and bleeding complications in patients with mechanical valve replacements - a prospective observational study. S Afr Med J 2006;96(8):710-713. https://pubmed.ncbi.nlm.nih.gov/17019493/ (accessed 22 May 2024).         [ Links ]

29. Kistan D, Booysen M, Alexander G, Madiba TE. A South Africa tertiary centre experience with redo mitral valve replacement. S Afr J Surg 2022;60(1):44-48. https://doi.org/10.17159/2078-5151/2022/v60n1a3192        [ Links ]

30. Jatene MB, Marcial MB, Tarasoutchi F, Cardoso RA, Pomerantzeff P, Jatene AD. Influence of the maze procedure on the treatment of rheumatic atrial fibrillation - evaluation of rhythm control and clinical outcome in a comparative study. Euro J Cardio-thoracic Surg 2000;17(2):117-124. https://doi.org/10.106/s1010-7940(00)00326-2        [ Links ]

31. Baumgartner H, Falk V, Bax JJ, et al. 2017 ESC/EACTS guidelines for the management of valvular heart disease. Euro Heart J 2017;38(36):2739-2791.         [ Links ]

32. Barlow JB. Aspects of mitral and tricuspid regurgitation. J Cardiol Suppl 1991;25:3-33. https://pubmed.ncbi.nlm.nih.gov/1888464/ (accessed 16 July 2024).         [ Links ]

33. Antunes MJ, Barlow JB. Management of tricuspid valve regurgitation. Heart 2005;93(2):271-276.         [ Links ]

34. Suri RM, Schaff HV, Dearani JA, et al. Determinants of early decline in ejection fraction after surgical correction of mitral regurgitation. J Thoracic Cardiovasc Surg 2008;136(2):442-447.         [ Links ]

35. Mkoko P, Cupido BJ, Hitzeroth J, Chin A, Ntsekhe M. Profile, presentation and outcomes of prosthetic valve endocarditis in a South African tertiary hospital: Insights from the Groote Schuur Hospital Infective Endocarditis Registry. S Afr Med J 2022;112(4):288. https://doi.org/10.7196/SAMJ.2022.v112i4.16146        [ Links ]

 

 

Correspondence:
R Meel
ruchikameel@gmail.com

Received 26 September 2024
Accepted 9 June 2025