CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 1, January – April 2024 22 AFRICA treatment and outcomes of patients with rheumatic MS in LMICs. In this study, left atrial thrombi were present in five patients, four of which could not be detected with a TTE but only with a TEE. This finding highlights the importance of pre-PBMV TEE. Similarly, other studies have reported that the sensitivity of TTE in detecting a thrombus in the left atrium or its appendages (posteriorly located) in patients with RHD was 32–50%.23,29 The sensitivity and specificity of TEE in identifying left atrial thrombi was 99% in another study.29 Among patients with left atrial thrombus, two were in normal sinus rhythm (their left atrial volume indexes were 88 and 90 ml/ m2). It is possible that these patients in sinus rhythm may have experienced paroxysmal AF owing to the dilated left atrium. In this cohort, one patient with left atrial thrombus had a history of stroke. Similarly, previous studies have shown the risk of arterial–systemic embolism is increased by left atrial thrombus and LASEC, particularly in left atrial thrombi with irregular surfaces and LASEC with moderate to severe intensity.23,30-33 In our study, all patients with left atrial thrombus had associated LASEC. Previously, it has been reported that LASEC increased the risk of left atrial thrombi and hence the expression ‘when there is smoke, there is fire’.34,35 In this study, nine patients in normal sinus rhythm had moderate- to severe-intensity left atrial spontaneous echo contrast (so-called ‘smoke’). The mean size of the left atrium for the occurrence of LASEC was 55.34 ± 11.24 mm. Left atrial thrombus (and ≥ grade 2/4 mitral regurgitation, bilateral commissural fusion) absolutely contra-indicate eligibility for PBMV.14,15 However, depending on certain clinical circumstances, experienced operators may deviate from these guidelines.23 For example, the approach for patients with left atrial thrombus is controversial.11 While most operators agree with the ACC/AHA guidelines to avoid PBMV,14,15 others argue that the risk of dislodging a thrombus is reduced by the low profile and manoeuverability of the Inoue balloon when done in experienced hands.36 Indications for anticoagulation are: history of systemic embolism, thrombus in the left atrium, prosthetic heart valve, AF or left atrium > 50 mm diameter/left atrium volume > 60 ml/m2.14,15 However, controversy exists on whether patients with rheumatic MS in normal sinus rhythm based on enlarged left atrium or LASEC should be anticoagulated.14,15,37,38 Patients with left atrial thrombus should be given a four-to-six-week pre-PBMV treatment with warfarin.11 There is an unmet need for alternative anticoagulation strategies (apart from vitamin K antagonists) in patients with moderate to severe MS and prosthetic heart valves because the new oral anticoagulants are neither safe nor effective, as evidenced by the Randomized Evaluation of Dabigatran in Patients after Heart Valve Replacement (RE-ALIGN) trial.39 Indeed, the INVestigation of rheumatiC AF Treatment (INVICTUS) trial results, which have just been published, have shown that rivaroxaban is outmatched by vitamin K antagonists for rheumatic AF.40 Findings from the INVICTUS trial underscore a need to improve anticoagulation control in LMICs, for instance, by ensuring the availability of point-of-care international normalised ratio (INR) devices at different levels of health facilities, including primary healthcare. Currently, in sub-Saharan Africa, there are great challenges with anticoagulation, with wide variation in its use and time in the therapeutic range of 27–56%.41,42 In our study, the mean Wilkins score was 8.6 ± 0.9, with a range of 8–12. Seven patients had a score ≥ 10, implying an ‘unfavourable’ Wilkins score. However, we obtained successful results in 10/12 patients with no immediate postprocedural complications. The improvement in the MVA and haemodynamics were similar between patients with Wilkins scores ≤ 8 and those with scores of 9–11. Similarly, previous studies13,43,44 have shown that in a population of young patients or those with fewer co-morbidities, PBMV gave a better survival rate despite an unfavourable Wilkins score (mean score of 9.5). In our cohort, the patients were young and with no co-morbidities. That is an important observation in selecting a candidate for PBMV, as it should not solely rely on Wilkins score. In addition, Almeida et al.45 have reported that PBMV is safe and effective in patients with rheumatic MS in patients with Wilkins scores ≤ 8 and 9–11; and with similar improvement in the MVA. Recently, Carvalho et al.46 reported no difference in all-cause/composite of all-cause mortality between the two groups after a follow up of 10 years. Another study from Khartoum by Suliman et al.47 that comprised patients with an average Wilkins score of 9 showed good immediate PBMV outcomes, similar to our findings. In its original description, a Wilkins score ≥ 12 predicted poor results with PMBV.8 In one large analysis, approximately 60% of patients with Wilkins scores 9–11 achieved a successful result with PMBV.48 Wilkins score ≥ 12 achieved significant improvement in MVA, although full success was uncommon (30%). PBMV relies on the mechanism of commissural splitting.14,15 The ideal valve anatomy would have commissural fusion, pliable leaflets and limited subvalvular apparatus calcification.23 If there is minimal commissural fusion, a successful result is unlikely.8 In patients with RHD, commissural fusion is the hallmark. On the contrary, in the Western world, most patients with significant MS are older with degenerative, calcified, less-pliable leaflets, making PBMV unsuitable.14,23 Our study showed that PBMV has good short-term outcomes in selected patients. In countries where RHD is endemic, PBMV is an alternative to mitral valve surgery, offering a similar survival rate despite a lower event-free duration, and its main advantage over surgery is the lower cost. Ambari and his colleagues48 have recently presented survival data of patients with rheumatic MS after PMBV in a LMIC, showing that PBMV was non-inferior to mitral valve surgery in terms of survival. On the contrary, in high-income countries, PBMV is still performed occasionally, not only because of the lower incidence of RHD but also because they are strict with the scoring system in selecting appropriate patients predicting safety and success.49 Furthermore, in high-income countries there is a higher level of skill and techniques among cardiothoracic surgeons, such as using minimally invasive techniques, which have been shown to provide quick recovery and long-term survival.50 PBMV is important in an LMICs where haemodynamically severe MS presents earlier in life, and young patients have thickened valve leaflets, presenting with or without concurrent regurgitation.51 It is also a bridging therapy to open-heart surgery for MS patients during pregnancy, postponement of valvular replacement for women to finish their childbearing time
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