Study Focuses on Permanent Pacemaker Predictors in TAVI vs. Surgery

NEW ORLEANS, LA—Permanent pacemaker implantation occurs at a higher rate after balloon-expandable transcatheter aortic valve procedures (TAVI) compared with surgery, often occurring early and as a result of atrioventricular block (AVB). According to data presented April 5, 2011, at the annual American College of Cardiology Scientific Session/i2 Summit, right bundle branch block (RBBB) is a major predictor of pacemaker implantation with TAVI, but not surgery.

According to Josep Rodés-Cabau, MD, of Laval University (Quebec City, Canada), while the higher likelihood of permanent pacemaker implantation is a known risk of TAVI, the factors that contribute to this conundrum are not well understood in balloon expandable valves compared with surgery.

Dr. Rodés-Cabau and colleagues analyzed the incidence of permanent pacemaker implantation within 30 days in 822 elderly patients with severe symptomatic aortic stenosis who were matched 1:1 based on ECG findings between 2002 and 2010 at their institution. The patients either received TAVI using the Edwards Sapien balloon-expandable aortic valve system (Edwards Lifesciences, Irving, CA) or underwent surgical valve repair

TAVI Patients Sicker

The average age was 81 years in the TAVI group and 80 years in the surgery group. About half of the patients had conduction abnormalities at baseline, including AVB, RBBB, and LBBB. In the TAVI group (n = 411), slightly more than half of the patients (54%) received a transfemoral procedure, while the rest (46%) were transapical. The TAVI group had a much higher disease burden than the surgical patients (n = 411), including more hypertension, higher STS score, lower LVEF, and smaller aortic valve area.

Following the procedures, permanent pacemaker implantation was more frequent in the TAVI group, with most patients in both groups requiring the procedure for complete AVB. Among just these patients, pacemaker implantation was again more frequent in the TAVI group, while among patients with severe bradycardia, which represented a minority, pacemaker implantation rates were similar regardless of treatment (table 1).

Table 1. Permanent Pacemaker Following Aortic Valve Procedure

The majority of conduction abnormalities occurred either during the procedure or within 24 hours in both the TAVI (83.4%) and surgery (78.6%) groups. In particular, all cases of AVB occurred within the 2 days following the procedure, and there were no new cases within 30 days in each group. Conversely, severe bradycardia occurred up to 7 days after each procedure.

The median time to pacemaker implantation was shorter in the TAVI group (2 days vs. 6 days; P < 0.001), with 30% of patients in the TAVI group receiving a pacemaker either during or within hours of the procedure. At hospital discharge, most patients in each group were on pace rhythm (80% with TAVI vs. 73% with surgery; P = 0.68). This was true for almost all of the TAVI patients with complete AVB (94%).

No clinical or procedural variables were associated with the need for permanent pacemaker implantation following TAVI. However, preprocedural RBBB was an independent predictor in the TAVI group (OR 8.61; 95% CI 3.14-23.67; P < 0.0001). There were no procedural, clinical, or ECG predictive factors in the surgical group.

Among the TAVI patients, those with RBBB had much higher rates of permanent pacemaker implantation (table 2).

Table 2. Pacemaker Implantation in TAVI Patients

The pacemaker implantation rate in surgical patients with RBBB was about 5%.

TAVI was associated with a higher rate of permanent pacemaker implantation compared to surgical aortic valve repair in elderly patients with severe aortic stenosis and similar baseline ECG findings, Dr. Rodés-Cabau concluded.

“Most patients in both groups needed pacemaker implantation because of complete AV block occurring either during or within 24 hours following the procedure,” he said. “The presence of baseline right bundle branch block predicted the need for pacemaker implantation in the TAVI group but not in the surgical group. These results should help to better identify the patients at risk for permanent pacemaker implantation following TAVI with a balloon-expandable valve and contribute to an improved clinical decision making process in patients eligible for either TAVI or surgical aortic valve replacement.”

Commenting on the results, panel member Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), referred to the recently released PARTNER findings.

Watch Out for Right Bundle Branch Block

“With the data presented by Craig Smith with the PARTNER trial, which is a randomized comparison, I think most people are pretty secure with this device in terms of a relatively low rate of pacemaker implantation,” he said. “There are device specific differences and that’s something we’re going to have to follow over the long term”

Panel member Andrew C. Eisenhauer, MD, of Brigham and Women's Hospital (Boston, MA), posited that “perhaps in the TAVI patients, the sicker they are the more conduction disease they have. And the more other clinical characteristics they have the more likely they are to have early heart block.”

Regardless, he added, “it’s good to know that right bundle branch block should be continually watched in our practice, and it’s also important to know that if heart block doesn’t happen early, it doesn’t happen.”

Source:

Rodés-Cabau J. Need for permanent pacemaker as a complication of aortic valve procedures: Comparison of transcatheter aortic valve implantation and surgical aortic valve replacement in elderly patients with severe aortic stenosis and similar baseline ECG findings. Presented at: American College of Cardiology Scientific Session/i2 Summit; April 5, 2011; New Orleans, LA.

Disclosures:

• Dr. Rodés-Cabau reports serving as a consultant for Edwards Lifesciences.

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• PARTNER: All-Cause, CV Mortality Lower in Patients Treated with TAVI vs. Standard Therapy at 1 Year