The results of a really interesting clinical trial were just reported at the annual meeting of the American College of Cardiology and simultaneously published online before print by the New England Journal of Medicine .
The trial, SIMPLICITY-HTN3, was designed to test the efficacy of renal artery denervation by radiofrequency (RF) ablation in the treatment of medication resistant hypertension. For those of you unfamiliar with the technique, it utilizes catheters similar to those used in intra-cardiac ablations by cardiac electrophysiologists. In this case, the ablation catheters are positioned in the renal arteries, and deliver RF energy through the arterial wall to the nexus of nerves in the surrounding tissue. In early reports of the technique, this “catheter based sympathectomy” led to stunning reductions in systolic blood pressure, and cardiologists were jumping on the bandwagon to do the procedure.
Cooler heads prevailed, and the recent trial was designed to address several methodologic limitations of the earlier reports. For me, the most interesting difference was the inclusion of a blinded control group, which was “treated” with a sham procedure. The sham included insertion of catheters into the renal arteries, along with renal artery angiography, but no ablation. The patients were all sedated, and the duration of the procedures was adjusted so that neither the patient nor family members could tell what had been done. The effectiveness of the blinding efforts was confirmed with patient questionnaires.
Here’s the really interesting part. There was no difference, not because the ablation failed to lower BP, but because the sham procedure lowered BP just as much as the “real” intervention. Once again we are reminded of the power of patients’ believing that they had undergone a therapeutic procedure.
I believe that tapping in to the strength of patients’ beliefs is one of the “unmeasurable” things that separate great doctors from technically proficient ones. Great doctors develop a therapeutic bond, characterized by mutual respect and trust. That trust leads to faith in the prescribed course of action, which leads to better results. Every “medicine-man” or shaman knew that to be the case. We should remember it too.
What do you think?