Tue 24 May_l 2016
Transcatheter aortic valve implantation is a technique for replacing the diseased aortic valve via keyhole techniques. This method was initially proposed to treat those patients who were deemed too risky for traditional surgery. By avoiding large incisions, and the need for a heart lung machine, there was a general, and understandable belief that where surgical risk was high, surgeons could still offer relief of the crippling symptoms of aortic stenosis (narrowed valve) such as shortness of breath and heart failure.
Well, interestingly, although the early outcome data in high risk patients undergoing TAVI has shown great promise, newer data is now beginning to raise predicted concerns around the longer term outcome following TAVI. Whilst this may not be important in higher risk patients with reduced life expectancy, it is very important for those patients who may have longer predicted life span. Some even argue that the financial interests in TAVI are, perhaps inappropriately widening the indications for TAVI to lower risk patients, and controversy prevails.
Recent data presented at the prestigious international conference EuroPCR 2016 certainly supports concerns about long term durability:
A Canadian and French team have reported the first long term durability of TAVI valves in 704 patients who underwent TAVI more than 5 years previously between 2001 and 2011. These patients had a mean age of 82 years and one would argue represent a medium to high risk cohort. After excluding patients who died within 30 days of TAVI, those with device failure immediately after TAVI and those having complex valve-in-valve procedures, 378 were left for analysis. These were followed up for up to 10 years with echocardiographic analysis. The types of TAVI valves included Edwards SAPIEN XT (36%), Edwards SAPIEN (50%) and Cribier-EdwardsTM valves (14%).
Only one hundred patients survived for at least five years after TAVI and were investigated for valve degeneration. Over this time the study identified 35 cases of valve degeneration. Approximately two-thirds of the failed valves were associated with intra-valvular regurgitation and the remaining third displayed valvular stenosis. A few rare cases also showed a mixture of stenosis and regurgitation. A significant number of valves showed degeneration between five and seven years after TAVI.
Kaplan-Meier estimates for the eight-year rate of structural valve degeneration was as high as 50%.
Commenting on the new findings, Pieter Kappetein, from Erasmus Medical Center, Rotterdam, the Netherlands stated:
“This is extremely important data and addresses the concerns that many people had when transcatheter heart valve were introduced: will they last as long as surgical bioprostheses? Can we therefore expand the indication to younger patient?” He adds, “Hopefully, the new generation of TAVI will last longer and there might also be a need for self-regenerating tissue-engineered heart valves. He concludes, “Expansion of TAVI indication should only take place in the confines of a randomised trial.”
TAVI remains a very exciting technology but we strongly believe that the technique should be restricted to surgically inoperable patients. Any expansion outside of this clinical indication should only be within the context of randomized trials. We have found the use of sutureless valves during traditional surgery to be a very reliable technology:
Credit to: Kardionet Sağlık
The Intuity sutureless valve is exactly the same as the sutured Perimount bovine valve and we expect the long term durability to be equally predictable and in excess of 80% and 10 years. The benefit of this technology over traditional sutured valves is much speedier implantation times, thus reducing the time on the heart lung machine. For now, we use this technology to expand our operative case mix, reserving TAVI for only the sickest patients, where symptom relief and swift recovery are favoured and where durability is not a compromise based upon the already limited life span of this group of patients.