CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 2, May – August 2024 AFRICA 113 mmHg (–17.0 to –1.0 mmHg) at six months; and –15.0 mmHg (–29.0 to –6.0 mmHg) at 12 months. The majority of patients receiving RDN treatment had ≥ 10 mmHg reduction in office systolic BP, with 64% achieving this goal at three months, 70% at six months and 68% at 12 months (Fig. 2). Despite the fact that the median number of antihypertensive medications remained constant throughout the follow-up period, 39% of patients receiving RDN treatment had a ≥ 20-mmHg reduction in office systolic BP at three and six months, and 45% had a reduction ≥ 20 mmHg at 12 months. Among the South African GSR subpopulation, there were no adverse events up to 12 months, except for a single spontaneous myocardial infraction. There were no incidences of death from any cause, stroke, new-onset renal disease or cardiac-related hospitalisation in the follow-up patients. Discussion In the analysis presented here of South African patients enrolled in the GSR, RDN was shown to lower both office and 24-hour ambulatory systolic BP in patients with uncontrolled hypertension, with durable reductions up to 12 months, which is consistent with previously reported GSR analyses.17-19 Since the report of the neutral efficacy results from the SYMPLICITY HTN-3 trial comparing sham and treatment groups,21 numerous randomised, sham-controlled RDN trials have demonstrated a treatment benefit in reducing office and 24-hour ambulatory systolic BP in hypertensive patients.11,12,22 More recent followup interim analyses of various high-risk groups from the GSR provide further evidence supporting the efficacy of RDN in reducing BP in a broad population with subgroups with different baseline risks and various co-morbidities.23,24 The efficacy results fromtheGSRSouthAfrica are particularly encouraging as South Africa has the highest prevalence of hypertension among sub-Saharan African countries, with patients of African descent having more complications from hypertension.15,25 Ten of the enrolled patients from the GSR South Africa were of African descent. This study of the South African GSR subpopulation also demonstrates the safety of the RDN procedure up to 12 months, with no instances of renal artery re-intervention or stenosis. The safety of RDN reported here is consistent with previously reported results from a metaanalysis of RDN, which found no major procedural or clinical adverse events up to three months.22 Nearly half the enrolled patients from South Africa had type 2 diabetes mellitus (Table 1). A recent study of high-risk hypertensive groups in the GSR reported that patients with type 2 diabetes mellitus had a 13.4 ± 25.9-mmHg reduction in office systolic BP 12 months after RDN.23 By comparison, the South Africa GSR cohort had a reduction of 16.9 ± 24.2 mmHg 12 months after RDN (Fig. 1). These studies underscore the potential benefit of RDN treatment in high-risk patients, such as those with type 2 diabetes mellitus. Non-adherence to prescribed antihypertensive medication is a prevailing challenge in controlling BP in hypertensive patients.7-9 For example, in the recent SPYRAL HTN-ON MED pilot study comparing RDN safety and efficacy between treatment and sham-control groups, patients were informed that medication adherence would be monitored at each follow up, yet by six months, nearly 40% of patients were non-adherent to their prescribed medications, based on liquid chromatography analysis of urine and plasma samples.12 The South Africa GSR cohort had a median of four antihypertensive medications prescribed at baseline, which was maintained throughout the 12-month follow up, although medication adherence was not evaluated in the GSR with drug or urine testing. Given the sizeable fraction of hypertensive patients world-wide that are unresponsive to traditional treatment options, including pharmacological medication, and persistent issues with non-adherence to medication, RDN may provide an attractive alternative treatment strategy to durably reduce BP in patients with uncontrolled hypertension. Limitations This analysis has several limitations. First, as the GSR is an all-comer registry, there was no control arm to account for potential placebo or Hawthorne effects on outcomes. Second, the GSR did not standardise follow-up procedures, therefore potentially limiting reporting of relevant events after RDN. It should be noted that the number of patients enrolled in the South African cohort was modest, and moreover, not all patients enrolled from South Africa completed 12 months of follow up at the time of this analysis. However, the office and 24-hour ambulatory systolic BP reductions over 12 months reported from this analysis of the South African cohort were consistent with previously published results from other GSR analyses.17 Conclusions RDN treatment safely reduced systolic BP in hypertensive patients enrolled in the GSR from South Africa to levels similarly reported in other GSR studies. Additionally, office and 24-hour ambulatory BP reductions from RDN observed in the registry were consistent with the benefits of RDN reported in randomised, sham-controlled clinical trials, demonstrating the potential of RDN as an alternative or complimentary strategy to traditional treatment options in lowering BP in patients with uncontrolled hypertension. Beth Ferri, PhD, CMPP and Benjamin Woods, PhD of Medtronic provided medical writing and editorial support. Marianne Wanten of Medtronic provided clinical study oversight. We thank Netcare Unitas Hospital and Life 3 months (n = 28) 6 months (n = 23) 12 months (n = 22) 64.3 39.3 69.6 39.1 68.2 45.5 100 90 80 70 60 50 40 30 20 10 0 Patients (%) ≥ 10 mmHg reduction ≥ 20 mmHg reduction Fig. 2. Percentage of patients with reduction in office SBP by 10 and 20% from baseline.
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