Is moderate sedation safer than general anesthesia for transcatheter aortic valve replacement (TAVR), or is it that lower-risk patients are more likely to receive moderate sedation? That is the question raised by a new 11,000-patient study that found 30-day mortality rates were 38% lower among TAVR patients who received moderate sedation than those who were administered general anesthesia.
“These results support our hypothesis that moderate sedation can lead to better clinical outcomes, and could have significant implications for patient care and for the process of the TAVR procedure,” said senior author Jay Giri, MD, MPH, assistant professor in the Cardiovascular Medicine Division at the Perelman School of Medicine at the University of Pennsylvania, in Philadelphia.
Dr. Giri, who presented the data at the Society for Cardiovascular Angiography and Interventions 2016 Scientific Sessions (abstract 14823), said his team knew anecdotally that they had good outcomes with moderate sedation for TAVR, “but we didn’t know what rigorous study of institutional data would reveal.”
Moderate Sedation Increasing
To determine whether their experience was reflective of larger clinical outcomes, Dr. Giri and his team turned to the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy Registry. They reviewed data from 10,997 registered TAVR patients who had undergone elective percutaneous transfemoral TAVR across nearly 400 institutions in the United States between April 2014 and June 2015.
According to the data, 15.8% (1,737/10,997) of the study patients had received moderate sedation for TAVR, and a steady increase in use of moderate sedation was noted over time (Figure). Patients who received moderate sedation were slightly older than general anesthesia recipients (82.4 vs. 81.8 years, respectively; P=0.01) and were more likely to have severe lung disease (14.6% vs. 12.7%, respectively; P=0.04).
Dr. Giri reported that 5.9% of TAVR procedures initiated with moderate sedation required conversion to general anesthesia.
Propensity-matched analyses that accounted for 51 clinical and demographic variables known to affect 30-day TAVR-related mortality showed that moderate sedation recipients were 28% less likely to die within that time frame than those who received general anesthesia. Moderate sedation recipients also were 31% less likely than general anesthesia recipients to meet a combined end point of stroke or death within 30 days, the findings showed.
Outcomes With Moderate Versus General Anesthesia for TAVR
Moderate Sedation General Anesthesia Odds Ratio P Value
30-day mortality 2.96% 4.01% 0.72 0.001
30-day death/stroke 4.80% 6.36% 0.69 0.001
TAVR, transcatheter aortic valve replacement
Dr. Giri and his team also examined resource utilization data and found the average hospital length of stay was six days among moderate sedation recipients, compared with an average of 6.7 days among general anesthesia patients (P<0.0001). Dr. Giri said his team expected a “much shorter length of stay, considering there is no need for intubation with moderate sedation.
“I think the study suggests that, when it comes to reducing hospital stay length, it’s not only a function of what we do in the operating room, but also of what we do outside the TAVR room,” Dr. Giri said. “There’s a historical precedent to treating TAVR patients in a certain way following their procedure, which means we need to create a culture change through the use of new clinical pathways in order to shorten hospital stays further.”
Possible Selection Bias?
While applauding the researchers for conducting the largest study on TAVR anesthesia-related outcomes to date, Laeben Lester, MD, assistant professor of anesthesiology and critical care medicine at the Johns Hopkins University School of Medicine, in Baltimore, said the retrospective study design limits the strength of the findings.
Specifically, he said, this study design leaves open the possibility of patient selection bias.
“For example, it is possible that patients who received general anesthesia were less likely to be able to lie flat, more likely to have pulmonary hypertension or had poor femoral artery access, which could mean they were sicker and at higher risk of worse outcomes to begin with,” explained Dr. Lester, who was not involved in the study.
For his part, Dr. Giri said the study’s statistical analyses were robust, and his team employed a validated TAVR risk model that was published in JAMA Cardiology (2016;1:46-52).
“And we added a few other variables, such as valve type and right ventricular systolic pressure, for example, which that model did not include—so it was a very thorough analysis,” Dr. Giri said.
Two conclusions that Dr. Lester believes can be drawn from the study are that the rate of conversion to general anesthesia is roughly 6%, which “underscores the need for continuous vigilance and preparation for urgent or emergent induction of general anesthesia,” and that TAVR can be performed successfully using moderate sedation in some patients.
“At Johns Hopkins, we now perform roughly half of our TAVR cases under mild to moderate sedation,” Dr. Lester emphasized.
As cardiologists at other institutions become more proficient at performing the procedure and anesthesiologists gain a “stronger sense” of which patients are ideal candidates for sedation, use of sedation for TAVR will likely increase, Dr. Lester said.