Interview Prof. Schmieder: Predictability of blood pressure reduction after RDN

Recor: Prof. Schmieder, you presented a poster¹  on predicting blood pressure reduction after renal denervation. Can you explain the key aspects of the study?

Prof. Roland Schmieder: The core question of the study was how to predict blood pressure reduction from renal denervation. When you look at the literature, it consistently shows that baseline blood pressure is the strongest predictor of the therapy’s effect. In our analysis, we wanted to quantify this influence.

For this study, we analyzed data from over 3,000¹  patients and compared their baseline blood pressure with the change in blood pressure after renal denervation. Unsurprisingly, a linear relationship emerged: the higher the initial blood pressure, the greater the reduction after treatment.

To illustrate: as a rule of thumb – with a baseline blood pressure of 150 mmHg, you can expect a reduction of about 5 mmHg. At 160 mmHg, it’s about 10 mmHg; at 170 mmHg, 15 mmHg; and at 180 mmHg, around 20 mmHg.

Recor: How reliable is this rule of thumb?

Prof. Roland Schmieder: It’s an average observation, but of course, there are confidence intervals that can be looked up in tables. But when a patient is sitting in front of you, you can say: “Well, the baseline blood pressure is the best predictor of how well your response will be.” This principle also applies to other parameters – for example, a high heart rate treated with a heart rate-lowering drug like ivabradine shows a similar relationship.

Recor: Is there a scientific explanation for this?

Prof. Roland Schmieder: The higher the initial value, the greater the effect of the treatment. This principle is known as the “law of initial value.” It was first described in 1931 by Wilder, a German scientist, who formulated it as the “the principle of initial value.”

So, if you start a program with patients who already have high blood pressure, you can expect a greater reduction. This way, you can give patients a realistic idea of what to expect based on average values.

Recor: So that means patients with very high blood pressure can benefit especially strongly?

Prof. Roland Schmieder: Exactly!

Recor: Was this effect solely due to denervation, or did medications also play a role?

Prof. Roland Schmieder: Both patients who were on medication and those without drug therapy were included. The rule applies regardless of the situation.

Recor: So this rule works both with and without medication?

Prof. Roland Schmieder: Yes, it doesn’t matter – it applies to patients with or without comorbidities. Because it’s a biological law. I often explain it to my patients like this: Based on previous studies, we know that with a baseline value of 160 mmHg, about three out of four patients experience a blood pressure reduction of at least 10 mmHg. That’s a simple and practical way to explain it.

References:

Prof. Roland Schmieder remarked: “It did not matter what type of RDN technology was used. This is because systolic blood pressure was also the strongest predictor in studies of renal denervation with ultrasound RDN, as we saw in the RADIANCE program. The RADIANCE program comprises RADIANCE HTN, RADIANCE II and TRIO – a total of over 500 patients.”

Recor Medical on uRDN: Individual results may vary.

Disclaimer: The interview features Prof. Schmieder’s medical expertise sharing insights on renal denervation. The views and opinions expressed are those of the doctor and do not necessarily reflect those of Recor Medical or other experts.