Practice Update - ESC Congress 2017

guidelines, it recommends physicians provide supplemental oxygen only when arterial oxygen saturation drops below 90% (class I indication). A fear that oxygen therapy could be harm- ful arose after the multicenter, randomized, controlled Air Versus Oxygen In myocar- Dial infarction (AVOID) trial, in 2015, which reported a larger infarct size in patients receiving oxygen therapy. “Routine oxy- gen therapy seems unnecessary in this patient group, but fortunately our data do not give any indication of increased risk for patients on oxygen,” said Dr. James. “So all of us who have used oxygen for decades can rest assured.” The DETO2X-AMI trial was the first large- scale randomized trial of oxygen therapy in patients with suspected myocardial infarction that was large enough to reveal meaningful findings on mortality and morbidity. The study enrolled six times more patients than all previous randomized trials of this therapy combined, and included a much broader range of patients, rendering the results relevant to everyday clinical practice. Dr. Boehm presented 3-month results of the first 80 patients, 38 of whom received renal denervation and 42 the sham proce- dure. Compared to baseline, at 3 months after the procedure, office-based systolic and diastolic blood pressure had declined by 10.0 mmHg (P < .001) and 5.3 mmHg (P = .008) in the renal denervation arm, respectively, vs declines of 2.3 and 0.3 mmHg (neither significant) in the sham arm, respectively. Regarding 24-h ambulatory blood pres- sure vs baseline, systolic and diastolic blood pressure of patients undergo- ing renal denervation decreased by 5.5 mmHg (P = .04) and 4.8 mmHg (P < .001), respectively. In the sham control arm, systolic and diastolic blood pressure decreased by 0.5 and 0.4 mmHg, respec- tively (neither significant). Decreases in systolic and diastolic office and 24-h blood pressure were confirmed by directly comparing between the renal denervation and sham groups. No major safety events were reported in either arm, even with the revised proce- dural approach. The latter increased the total number of ablations and included denervation in the branch arteries. Dr. Boehm explained that the results – published simultaneously online in The

highly focused ultrasound), not only to support these preliminary results but also to investigate whether an escape phenomenon might occur in hyperten- sion in the long term (reports exist of renal nerve regrowth after catheter-based renal denervation in animal models) and the unknown risk of de-novo renal artery stenoses associated with the new cathe- ters.”

Lancet – provided biological proof of prin- ciple of the efficacy of renal denervation and will inform the design of a larger, more definitive trial of the approach. Dr. Boehm concluded, “The effective- ness of renal denervation in this study may have been due to the new proce- dural approach, which aimed to achieve complete denervation, and the fact that patients were not taking antihypertensive medications, which may have confounded the results of previous studies.”

PracticeUpdate Editorial Team

He added, “With consistent and significant drops across ambulatory and office-based blood pressure – including both systolic and diastolic measurements – we are con- fident to be moving forward with a pivotal trial so that doc- tors and patients may have an alternative approach to lowering blood pressure.” In a recent editorial about the study in The Lancet , Michel Azizi, MD, PhD, with the Paris Descartes University, France, noted that “More studies are needed with the Spyral and other catheters and using different technologies (e.g.,

© ESC Congress 2017 – European Society of Cardiology

know if oxygen is beneficial and that’s why we have to do this [study] – they could accept that,” he said. “Now we have good data, with many patients, and I think practice will change.” “We saw that myocardial infarction meas- ured by very sensitive biomarkers was virtually identical between the groups, which is good for us because we’ve been using this stuff for ages,” said Dr. Hofmann. “Can you imagine if we had harmed our patients? It would have been terrible.” In an accompanying editorial in the New England Journal of Medicine , Joseph Loscalzo, MD, PhD, of Brigham and Women’s Hospital, Boston, wrote that while themechanisms underlying the adaptation to myocardial ischemia are complicated, the results of DETO2X-AMI were straight- forward and indisputable: “supplemental oxygen provides no benefit to patients with acute coronary syndromes who do not have hypoxemia – it is clearly time for clinical practice to change to reflect this definitive evidence.”

The study’s registry-based randomized clinical trial protocol employed national registries including SWEDEHEART for randomization, case record forms, and follow-up. Dr. Hofmann said, “Using this design, we could enroll 6629 patients with high-quality data in less than 3 years and keep overall costs to a fraction of a conventional randomized trial.” Dr. Hofmann noted that for the general patient with suspected myocardial infarc- tion, widespread use of supplemental oxygen is no longer warranted, despite being a firmly entrenched among physi- cians and emergency providers who treat patients with acute coronary syndrome. Dr. Hofmann explained that when they began the trial there was resistance, with physicians arguing that oxygen shouldn’t be taken away from patients with acute coronary syndrome. He and colleagues argued that there was simply no evidence to support supplemental oxygen, that it was simply “one of those things” that had always been done. “When it came down to it, and you explained it to physicians – that we don’t

PracticeUpdate Editorial Team

ESC Congress 2017 • PRACTICEUPDATE CONFERENCE SERIES 9