Hypertension Treatment Failure

Blood pressure is rather a squirrelly thing.  We know that it increases with exertion, aging, for some with increased salt intake, and that chronic high blood pressure is associated with strokes, or cerebrovascular accidents, to use the vernacular, and can have pronounced ill effects on the heart and kidneys.  Thus the medical establishment has for many years striven to keep blood pressure under control, ideally about 120/80mm Hg, and that a multitude of medicines working by different mechanisms have been developed for this purpose.  But, as Rick and I discuss on PodMed this week, what about the 5-15% of people whose blood pressure is very high and who don't seem to respond to medical therapy?  Ah, ever resourceful, enter nerve ablation to the blood supply to the kidneys, the renal arteries. The darling of the intractable hypertension treatment world, this week's New England Journal of Medicine reports a trial in which this intervention falls from grace with a resounding thud. What happened?

Incredibly, this trial reports the first randomized, blinded prospective study to examine the utility of ablating the sympathetic nerves to the kidney using radiofrequency ablation in the control of hypertension.  For the non-medical types who may read this, the sympathetic nervous system provides us with our 'fight or flight' response, where we can go from a resting state to ready for anything in mere moments, largely because of two hormones, epinephrine and norepinephrine. A chronic state of chatter in this system has been linked to hypertension in the past. Previous unblinded trials seemed to show a huge benefit in treatment refractory high blood pressure or hypertension by ablating those nerves and the procedure is in use worldwide.  In this trial, in a 2:1 ratio, 535 patients with treatment resistant hypertension were assigned respectively to either radiofrequency ablation or a sham procedure.  That, as Rick opines, is the key, as the sham procedure bears every resemblance to the actual ablation, allowing for much more revelatory comparison.

The endpoints of the trial included office-measured blood pressure 6 months after the procedure or its likeness, and 24 hour ambulatory blood pressure, and the conclusion is simple: it didn't work.  The change in systolic blood pressure (the high number) for those who had the actual ablation was a reduction of about 14mm Hg while those who were sham-treated saw reductions of about 12 mm Hg.  Reductions were even more modest in the 24 hour ambulatory measurements.  Okay, then.  Time to turn toward other strategies for blood pressure management, and by the way, those numbers are being recalculated all the time as normal aging is considered as well as other factors. As I am so fond of advocating, avoidance of procedures is almost always a good thing, and here's another for the seemed like a good idea at the time heap.

Can a common erectile dysfunction medication help men who are having radiation therapy for prostate cancer avoid ED? That's another topics this week from JAMA, and in the same journal a look at transfusion risk.  Another for NEJM: what about bariatric surgery in people with diabetes after three years of follow-up?  Until next week, y'all live well.

 

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