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Transcatheter aortic valve replacement (TAVR) appears to be a safe and effective treatment for patients with severe aortic valve regurgitation alone who are not candidates for surgery, according to a study published online February 20, 2013, ahead of print in the Journal of the American College of Cardiology.

The findings, from a small registry, were previously presented at the annual Transcatheter Cardiovascular Therapeutics scientific symposium in October 2012 in Miami, FL.

Investigators led by David A. Roy, MD, of St. George’s Hospital (London, United Kingdom), evaluated 43 nonsurgical patients with severe aortic regurgitation but no stenosis who underwent off-label TAVR with a CoreValve bioprosthesis (Medtronic, Minneapolis, MN) at 14 centers in Europe and Israel up to July 2012.

Almost 1 in 5 Needs a Second Valve

The devices were successfully implanted in all but 1 patient (97.7%). However, 8 patients (18.6%)—all without valve calcification—required a second valve during the index procedure due to residual regurgitation. By comparison, none of 17 patients with calcification needed a repeat procedure to achieve an acceptable result (P = 0.014). One patient required conversion to open surgery.

After TAVR, grade I or lower regurgitation was present in most patients (79.1%). However, 5 of the 8 valve-in-valve patients had grade II regurgitation and 1 had grade III. Taking the latter results into account, overall success, as defined by Valve Academic Research Consortium (VARC) criteria, was 74.4%.

At 30 days, the majority of patients were in NYHA functional class I or II, and mean LVEF had improved from 45.5 ± 12% at baseline to 49.6 ± 14.2%  (P = 0.02). There were only 2 major strokes, 1 death due to cardiovascular causes, and no MIs (table 1). A permanent pacemaker was required for new conduction abnormalities in 5 patients (16.3%).

Table 1. Safety and Clinical Outcomes^a

^a According to VARC criteria.

Neither need for a second valve nor postprocedural regurgitation predicted 30-day mortality (P = 0.18 and P = 0.13, respectively).

Explaining why use of TAVR has been uncommon in patients with severe aortic regurgitation alone, the authors observe that the condition is far less prevalent than aortic stenosis or a mixed etiology of stenosis and regurgitation. Also, pure regurgitation tends to occur in younger individuals, who are more likely to be eligible for surgery. Moreover, patients solely with regurgitation have a more complex and variable anatomy, making a transcatheter strategy more difficult than in conventional TAVR patients, they note.

Residual Regurgitation a Sticking Point?

Despite demonstration of the feasibility of TAVR in this registry, the authors stress that residual regurgitation is an important issue since several studies have shown that regurgitation greater than grade II after treatment is associated with worse outcomes.

Noting the high incidence of need for a second valve, the investigators say this phenomenon appears to correlate with the absence of valvular calcification, which in turn reduces fixation of the valve frame at the annulus and results in malpositioning. “This problem may be overcome by valve designs that are fully retrievable and respositionable, and valvular fixation may be improved, even in the absence of calcium, with new anatomically oriented valve designs,” they suggest.

In a telephone interview with TCTMD, Josep Rodés-Cabau, MD, of Laval University (Quebec City, Canada), congratulated the authors for exploring “a new frontier” for TAVR. “This is a very different game compared with patients with predominant insufficiency but aortic calcification, which is the disease for which [TAVR has] been very successful thus far,” he said.

A Challenging Cohort

However, TAVR is definitely more challenging in this group, Dr. Rodés-Cabau said, as evidenced in part by the fact that a significant proportion of patients needed a second valve during the procedure. Even so, he commented, rates of major complications such as stroke and mortality were no worse than those seen in stenosis patients.

Despite the relatively small number of patients studied, the authors venture some technical recommendations, Dr. Rodés-Cabau noted, such as using 2 pigtails to define the level of the annulus and facilitate accurate valve positioning. Whether another practice—higher-than-recommended valve oversizing, as was done in a few patients—is associated with better results remains to be seen, he said, adding, “I’m sure we’ll learn a lot more over the next 2 or 3 years.” 

Dr. Rodés-Cabau said the choice of CoreValve, which was used exclusively in this study, makes sense because the device’s design tends to minimize the risk of ventricular embolization. 

In addition, he observed that the centers in the registry all have a high level of experience with TAVR. Given the technical challenges of the procedure in this population, its use should be restricted to highly skilled operators, he advised, adding, “That is the best way to ensure that education regarding this novel application is advanced. 

“TAVR in this patient niche is a work in progress,” Dr. Rodés-Cabau concluded. “The authors have opened the door, and no doubt we will see more series in these types of patients with probably some technical improvements. We have to be cautious, but this is an important step forward.” 

Study Details

Mean age was 75.3 years and slightly more than half of patients were female (53%). Severe comorbidities were common, with a mean logistic EuroScore of 26.9 ± 17.9% and mean Society of Thoracic Surgeons score of 10.2 ± 5.3%.

Mean annulus size, assessed by CT or transesophageal echocardiography, was 24 ± 2.3 mm. In general, devices were oversized by 20% with respect to the annulus diameter, according to standard recommendations. TAVR was performed via transfemoral access in the majority of subjects (n = 35), but 4 patients were treated via the subclavian route, 3 via the direct aortic approach, and 1 by carotid access.

Source:

Roy DA, Schaefer U, Guetta V, et al. Transcatheter aortic valve implantation for pure severe native aortic valve regurgitation. J Am Coll Cardiol. 2013;Epub ahead of print.

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