Initial Experience with Renal Denervation for the Treatment of Resistant Hypertension - The Utility of Novel Anesthetics and Metaiodobenzylguanidine Scintigraphy (MIBG)

Abstract

Background:The Symplicity-HTN 3 trial failed to show significant difference in blood pressure (BP) lowering between patients undergoing catheter-based renal denervation (RDN) and the sham-procedure arm of the study. However, there is still optimism about the role of RDN in the treatment of resistant hypertension, because identification of patients with increased sympathetic activity thus being good RDN responders, improvements in the RDN procedure and new technology RDN catheters are all expected to lead to better RDN results. We present our initial experience with RDN for the treatment of resistant hypertension, and the utility of novel anesthetics and cardiac 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG).Methods and Results:Seven patients with resistant hypertension underwent RDN and were followed up for 6 months. MIBG was performed before RDN, in order to estimate sympathetic activity and predict the response to RDN. All patients were sedated with dexmedetomidine and remifentanil during RDN. All patients tolerated the procedure well, were hemodynamically stable and their peri-procedural pain was effectively controlled. A median of 7.6 ± 2.1 and 6 ± 1.4 ablations were delivered in the right and left renal artery respectively, making an average of 6.8 burns per artery. No peri-procedural or late complications - adverse events (local or systematic) occurred. At 6 months, mean reduction in office BP was -26.0/-16.3 mmHg (p=0.004/p=0.02), while mean reduction in ambulatory BP was -12.3/-9.2 mmHg (p=0.118/p=0.045). One patient (14.3%) was a non-responder. None of the cardiac 123I-MIBG imaging indexes(early and late heart-to-mediastinum (H/M) count density ratio, washout rate (WR) of the tracer from the myocardium) were different between responders and non-responders.Conclusion:Patients with resistant hypertension who underwent RDN in our department had a significant reduction in BP 6 months after the intervention. 123I-MIBG was not useful in predicting RDN response. Dexmedetomidine and remifentanil provided sufficient patient comfort during the procedure, allowing an adequate number of ablations per renal artery to be performed, and this could probably lead to improved RDN results.

Estratificação de Risco e Avaliação da Atividade Simpática Cardíaca Utilizando Imagem Miocárdica com [123I] MIBG na Denervação Renal

“…A MIBG-C foi realizada em pequenas coortes de pacientes com DR para avaliar a atividade simpática, mas os resultados foram bastante divergentes, relatando diminuições na WR, 5 aumentos na RCM 10 tardia ou nenhuma alteração. 11 Esse método de imagem também tem sido considerado útil para avaliar a atividade simpática cardíaca no contexto de insuficiência cardíaca, podendo estimar o prognóstico e a resposta ao tratamento. De fato, no estudo ADMIRE-HF, uma taxa significantemente menor de eventos e morte cardíaca foi observada em pacientes com um RCM tardia ≥ 1,6.…”

Contribuição da cintilografia com metaiodobenzilguanidia-123 na predição da resposta pressórica e na quantificação da denervação simpática renal em pacientes com hipertensão arterial sistêmica resistente

“…Estudos com pequenas coortes de pacientes com HAR utilizaram a cintilografia com MIBG-123I após DSR para avaliar a atividade simpática cardíaca. Os resultados não foram reprodutíveis, apresentando diminuições na WR (99), aumentos na RCM tardia (100) ou nenhuma alteração (101). Já no contexto de insuficiência cardíaca, a utilidade está bem estabelecida, estimando o prognóstico e a resposta ao tratamento medicamentoso (102); vale ressaltar que a quantidade de dados publicados sobre cintilografia com MIBG-123I para a avaliação da inervação simpática renal é muito limitada.…”