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Structural heart disease
August 2013
Transcatheter Valve News Transcatheter approaches to managing isolated aortic regurgitation
SANJEEVAN PASUPATI
COMMENT & ANALYSIS
Successful outcomes have been reported with the off-label use of transcatheter aortic valve implantation (TAVI) in patients with pure aortic regurgitation. However, there are several challenges of using TAVI in this group of patients (eg. they have poor fixation properties). Sanjeevan Pasupati reviews the data for TAVI in patients with aortic regurgitation and also discusses data for a device that has been specifically designed to enable the use of TAVI in these patients
T
he 10-year mortality rate of untreated severe aortic regurgitation is 34% and the 10-year heart failure rate is 50%. Additionally, 50% of patients with significant symptoms die within one to two years if they do not undergo corrective surgery; therefore, aortic regurgitation is a lethal disease in its own right. Furthermore, late surgical intervention for aortic regurgitation is associated with a higher mortality rate compared with early intervention.
The Euro survey showed that one third of patients with severe, symptomatic, single-valve heart disease do not undergo a corrective intervention—most frequently due to comorbidities. This survey also showed that 8% of patients with pure aortic regurgitation did not undergo aortic valve replacement when indicated. The number of TAVI procedures is growing exponentially and the procedure is finding its niche as a treatment for severe aortic stenosis. In TAVI, the valves are anchored in the calcified annulus and leaflets of the native valve, which is somewhat constrained due to the calcification. However pure aortic regurgitation patients have poor fixation properties due to poor leaflet and annular calcification with large and unconstrained annulus, increasing the risk of early and late malposition or embolisation of the percutaneous heart valves.
With no dedicated system on the horizon, off-label
CoreValve (Medtronic, Minneapolis) and Sapien (Edwards Lifesciences) TAVI valves have been implanted in selected high-risk patients with pure aortic regurgitation. Valves are oversized, risking annular rupture, to help anchoring. After initial reports showed good results, use of TAVI in patients with pure aortic regurgitation has become more widespread. In a small series, the CoreValve was implanted in 43 patients with pure aortic regurgitation using the transfemoral approach. In these patients, 21% resulted in residual moderate-to-severe regurgitation; 18.6% required a second valve due to the residual regurgitation due to poor anchoring; after receiving the second valve, 75% of patients were still left with significant regurgitation. Additionally, after undergoing TAVI with the CoreValve, one patient in the series crossed over to cardiac surgery because they continued to have severe regurgitation. These results illustrate the challenges in implanting a transcatheter valve in this anatomy. The 30-day survival in this series was 91%. Another, recently published, series reported the three-month follow-up outcomes of using (off-label) the JenaValve (JenaValve Technology) with the transapical approach in five patients with pure aortic regurgitation.
The positioning feelers and the lower stent portion of the JenaValve clips the native aortic leaflets to aid the anchoring, eliminating the need for leaflet and annular calcification and over sizing of the transcatheter valve. The results of the series indicated complete (100%) device success was achieved in all patients with trivial or no residual aortic regurgitation. However, bicuspid aortic valve or significant native leaflet calcification may possess a challenge for such a device to be implanted and may prove a relative contraindication.
The Helio aortic dock
The Helio aortic dock (Edwards Lifesciences) is the first dedicated system designed to address pure aortic regurgitation. The self-expanding, cloth-covered nitinol docking system is brought transfemorally to sit outside the native aortic leaflets and the current version of the Edwards transcatheter heart valve is brought transapically and deployed, sandwiching and anchoring on the native leaflets. At EuroPCR (21–24 May, Paris, France), we presented the one-year follow-up data for four first in human high-risk patients with severe aortic regurgitation who had undergone TAVI with the Helio dock system at our centre. In these patients, 100% device success was achieved with no procedural mortality. Additionally, no device embolisation or dislocation was noted at early or at late follow-up. There was no significant residual aortic regurgitation noted immediately or up to one year with all patients achieving symptom improvement. The next step will be to use the TF-TF system so that both the Helio dock and the heart valve are delivered transfemorally—making the procedure a pure percutaneous approach. In the absence of calcium, using the native leaflet to anchor the heart valve seems to be efficacious in achieving valve position and providing a good seal to reduce aortic regurgitation. Long-term stability of such systems and favourable remodelling of the aortic root is yet to be seen in future studies.
Sanjeevan Pasupati, Specialist in Coronary and Structural Heart Disease Intervention, Waikato Hospital, Hamilton, New Zealand
Transcatheter aortic valve system demonstrates excellent 30-day outcomes
A
t EuroPCR (21–24, Paris, France) Direct Flow Medical announced that it had met its primary endpoint in the fully-enrolled, 100-patient DISCOVER CE mark trial by achieving 99% freedom from all- cause mortality at 30 days.
Patients were treated with the Direct Flow Medical transcatheter aortic valve system and demonstrated excellent results relative to overall patient haemo- dynamics, as well as the avoidance of post-procedural aortic regurgitation and adverse events. The DISCOVER trial full 30-day outcomes were recently presented by trial investigator Joachim Schofer
from the Medical Care Center, Hamburg, Germany.
The Direct Flow Medical transcath- eter aortic valve system is designed to minimise the risk of aortic regurgita- tion following transcatheter aortic valve implantation (TAVI). In the DISCOVER trial, 99% of patients experienced mild or less aortic regurgitation, with 73% experiencing none/trace aortic regurgita- tion. The mean gradients pre-procedure, at discharge and out to 30 days of 46mmHg, 14.1mmHg and 12.6mmHg, respectively, demonstrated the system’s ability to significantly reduce, and then maintain, low gradients over time. All
haemodynamic outcomes were assessed and reported by an independent imaging core laboratory. The Valve Academic Research Consortium (VARC) defined Combined Safety rate was 89%. Within 30 days, there were two strokes (major or minor) and one patient experienced a myocardial infarction. There were only two major vascular complications, despite accessing vessels as small as 5.2mm. The VARC defined Device Success rate was 91%. No patient required rapid pacing during deployment or post-dilatation follow- ing deployment, minimising the risk of haemodynamic stress for patients.
At 30 days, 83% of patients had improved by more than one New York Heart Association (NYHA) functional class, and 68% were classified as NYHA class I. The average age of patients in the trial was 83.1 years, with a mean logistic euroSCORE of 22.5%.
“These results are unprecedented for a
TAVI device,” said Schofer. “The Direct Flow Medical system is demonstrating in this landmark trial that it can successfully treat aortic stenosis with low mortal- ity, whilst addressing the issue of aortic regurgitation in a clinically meaningful way in order to significantly improve patient outcomes.”
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