Among patients undergoing transfemoral transcatheter aortic valve replacement (TAVR), implanting the balloon-expandable Edwards SAPIEN 3 valve with higher placement — in a position just 1.5 mm under the noncoronary cusp — led to greater than 50% reductions in rates of conduction abnormalities and 30-day permanent pacemaker implantation compared with conventional valve deployment.
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So found a study comparing outcomes in more than 1,000 patients who underwent TAVR at Cleveland Clinic before or after transition to the new deployment method. The results were published online January 12 in Circulation: Cardiovascular Interventions.
“As TAVR use increases among patients with longer life expectancy, finding new ways to improve the procedure is especially important,” says the study’s senior author, Samir Kapadia, MD, Chair of Cardiovascular Medicine at Cleveland Clinic. “We found that the high deployment technique for aortic valve implantation appears to be a significant step forward, as outcomes improved without compromising procedural safety or valve hemodynamics.”
Conventional TAVR puts conduction tissue at risk
Although TAVR is considered a safe alternative to surgery for patients with severe, symptomatic aortic valve stenosis, it is well known to be associated with risk of new-onset conduction disturbances and permanent pacemaker requirement. Conventional deployment of the balloon-expandable SAPIEN 3 valve results in a ratio of valve frame in the aorta to left ventricular outflow tract of 70:30 or 80:20, a level that may put pressure on conduction tissue at and below the annular plane (see Figure).
Figure. Differences between the conventional and high deployment techniques for placing the SAPIEN 3 valve. LAO = left anterior oblique; RAO = right anterior oblique; LCC = left coronary cusp; RCC = right coronary cusp; NCC = noncoronary cusp.
In April 2017, Cleveland Clinic TAVR operators started to use a novel high deployment technique to achieve higher implantation of the SAPIEN 3 valve, with the goal of reducing impairment of the conduction system. From January 2018 on, all TAVR procedures using the SAPIEN 3 valve performed at the institution employed the high deployment technique.
All consecutive patients who underwent transfemoral TAVR with the SAPIEN 3 valve at Cleveland Clinic between April 2015 and December 2018 were included in this retrospective study. Of the 1,028 total patients, 622 (60.5%) underwent the conventional deployment technique and 406 (39.5%) underwent the high deployment technique. Overall, the median patient age was 82.7 years, and the median Society of Thoracic Surgeons risk score was 4.9 (interquartile range, 3.6-7.3).
Patients with a preexisting permanent pacemaker were included in the overall analysis but were excluded from the endpoint analyses of the need for a new permanent pacemaker and new onset of conduction abnormalities.
Key changes observed with adoption of the high deployment technique included the following:
- Implantation depth into the left ventricular outflow tract was significantly reduced. Specifically, the mean depth declined from 3.2 ±9 mm with the conventional deployment technique to 1.5 ± 1.6 mm with the new technique (P < 0.001). Although implantation depth using the conventional technique declined significantly over the course of the study, the mean depth remained larger than with the high deployment technique.
- 30-day permanent pacemaker requirements significantly fell. The rate decreased from 13.1% with conventional deployment to 5.5% with high deployment (P < 0.001).
- Conduction abnormalities became significantly less frequent. Rates of complete heart block dropped from 11.2% to 3.5% (P < 0.001), and rates of new-onset left bundle branch block declined from 12.2% to 5.3% (P < 0.001).
Additional key outcomes were similar between the two techniques:
- Successful implantation occurred in both groups. There was no conversion to open-heart surgery, second valve implantation with the first TAVR, or coronary occlusion during TAVR. One patient in the high deployment group (0.2%) had valve embolization (P = 0.216). There was no difference in mortality between the two groups, and 30-day stroke rates were comparable.
- Hemodynamic measures were comparable. No significant differences were found in mild or moderate-to-severe aortic regurgitation at one year. Although the high deployment technique resulted in slightly higher one-year mean and peak gradients that reached statistical significance (P = 0.042 and P = 0.026, respectively), the differences were not clinically meaningful, and the Doppler velocity index was similar between the two groups.
Careful placement is critical
The study report describes the technique for achieving high valve deployment. The technique was applied to all types of aortic root anatomy, in different angulations and with varying degrees of the valve being centered in the annulus. The authors share the following tips:
- Make sure the valve is in the appropriate position according to the noncoronary cusp (usually the deepest of the sinuses) in the right anterior oblique/caudal projection.
- Optimize fluoroscopic angles to remove any parallax from the valve.
- Identify the coplanar view on intraoperative angiography, which is achieved by pre-procedural planning using contrast-enhanced multidetector CT of the aortic root.
- Position the valve based on the superior aspect of the most proximal (or inferior) set of stent struts, seen as a radiolucent line on the crimped SAPIEN 3 valve.
“As a result of our experience, we recommend that high deployment of the SAPIEN 3 valve be adopted to decrease implantation depth and improve patient outcomes after TAVR,” concludes Dr. Kapadia.