TAVI Annual Report 2011

TAVI Annual Report 2011

TAVI (Transcatheter Aortic Valve Implantation).

Summary

TAVI outcomes in Sweden are at least as good as or better than previously presented in international datareports. Especially gratifying is the low frequency of stroke at 30 days, at 1.5 % and the low 30-day mortality of 6.4 %. The number of procedures increased in the last year from 144 implants in 2010 to 209 implants in 2011, with no apparent indication drift in indication. The selection of patients seems to have been adequate. The mean age and risk-factor load score of patients treated continue to be high, and most were -decidedly symptomatic prior to the procedure.
Even for a selected group of the very elderly patients, ≥ 90 years, the outcomes are very good very good outcomes are shown.

Background

Aortic valve stenosis is the most common indication for valve replacement in Sweden today. As Because aortic stenosis is in most cases is a degenerative disease, rising life expectancy will likely lead to increased prevalence of patients with symptomatic aortic stenosis. Untreated, symptomatic aortic stenosis has a poor prognosis, with rapid progress to heart failure and death.

Open surgical treatment with replacement of the degenerated valve with a mechanical or biological valve prosthesis is the prevailing method for treatment of aortic stenosis. Surgical Aaortic valve operation replacement (SAVR) has a well documented effect for relief of good symptoms-relieving effect and entails a virtuallyleads to a normalized prognosis life expectancy for the patients compared to the general population within their age group. In recent years there has been a trend to more frequently implant choice has been to use biological valves in SAVRopen surgery to a greater extent than in the past.

TAVI has been developed as an alternative catheter basedpercutaneous therapymethod for treating aortic stenosis in patients who for various reasons are deemed to be inoperable or at too high riskfragile for SAVRopen surgery. The first implant in a human was carried out in 2002. The first implant in Sweden was then performeddone in 2008. Currently more than 50 000 implants have been performed worldwide.

The TAVI Registry was established in 2010 in response to the express wishes from the authorities that developments in the country and the outcomes of treatment should be monitored and evaluated systematically.

This year’s report also includes analyses of patients treated in 2008 and onwards. The development and operation of the registry is done performed under the aegis of UCR. The TAVI Registry is directed by a working group with participants from all units hospitals performing implantsTAVI.

Degree of coverage

All patients undergoing TAVI in the country have been registered, thus the degree of coverage is 100 %.

Purpose

The purpose of the registry is, among other things, to create an instrument to enable quality control at both the centre and national level. The registry also makes it possible to follow up adherence to existing guidelines, thereby enabling the detection of any indication drift.

As the method is relatively new, long-term follow-up is crucial, regarding both long-term performance of the implanted valves as well as prostheses and complications and survival.

Achieved outcomes must also be evaluated in relation to published data, and in the long term, comparisons with surgical aortic valve replacements open surgery may be performedmade.

The registry may also come to serve as a tool for future studies.

Outcomes/methods

Procedures are primarily done transfemorally (via the fermoralgroin artery) or transapically (via the apex of the heart) but can also be done via the arteria subclavian artery (the artery under the collar bone) and throughvia direct puncture of the aorta.

Currently two systems are used in Sweden, Edwards Sapien and Medtronics CoreValve. The Edwards Sapien prosthesis consists of a tubular metal frame with a biological tissue valve of bovine pericardium that is balloon-expanded in the aortaic position. The initial Sapien Earlier models required a femoraln introducer sheath of 223–245 F (8 mm), which limited the number of suitable patients entailed difficulty in transfemoral procedures owing to the large sheath dia-meter. Currently a 18–19 F (6 mm) is required for the third generation Sapien XT is required. The system can be used for transapical and transfemoral procedures and for direct puncture of the aorta.

The CoreValve prosthesis consists of a self--expanding nitinol frame in which a biological valve of porcine pericard is mounted. The CoreValve prosthesis can be used for transfemoral implants, implants via thea. subclavian artery, and for direct puncture of the aorta From the beginning the CoreValve prosthesis has featured an 18 F introducer.

TAVI is currently only performed today only at university hospitals with access to cardiothoracic surgery: Sahlgrenska University Hospital in Gothenburg, Scania Skåne University Hospital-Lund, Linköping University Hospital, Linköping, Örebro University Hospital, Örebro, Karolinska University Hospital, Uppsala University Hospital, and Norrland University Hospital, Umeå.

The various hospitals have thus far chosen to use only one of the two available systems. Thus, CoreValve is used by Karolinska University Hospital, Uppsala Univesity Hospital, and -Sahlgrenska University Hospital; the others
use the Sapien valve.

In 2011, 209 implants were performed in Sweden and the accesss sites were as follows, , 9 via a. subclaviasubclavian, 45 transapically, and 155 transvia a. femoralis. The distribution across hospitals and by implant method is shown in Figure 1.

A total of 87 Sapien valves and 122 CoreValves were used. Compared with 2010, the share of CoreValves has grown, which is explained by major activity at Karolinska and a dramatic increase in activity at Uppsala University Hospital.

There has been a continuous increase in the number of implants in during 2008–2011, as is shown in Figure 2.

A trend towards a greater share for transfemoral procedures can be seen, probably for several reasons. Among other things, better delivery systems have enabled transfemoral procedures in more patients treated with the Sapien prosthesis (Figure 3).

The gender distribution among patients treated is shown in Figure 4. The distribution was relatively even, with 116 men and 93 women. This differs from 2010 figures, where women were somewhat more frequently represented than men somewhat more than men (74/69).

The mean age of patients treated was over 80 years (Figure 5).

Logistic Euroscore

The Logistic Euroscore is a measure used to estimate the operative risk for coronary bypass surgery. The risk is generally over-estimated by the Logistic Euroscore by 50–70 %. A score of 20 % is supposed to indicate an estimated operative mortality of 20 %, but in reality this turns out to be around 7–10 %. Even though the Logistic Euroscore was not developed for use with valve surgery and even less with TAVI, it remains the dominant way of describing patient risk in the procedure.
It is also used as a criterion for selection for whichof high risk patients are regarded suitable for TAVI, where a score of > 20 % is normally required. A new Euro-score (Euroscore II) has been developed and is being registered continuously both in the Heart Surgery Registry and the TAVI Registry. As yet there are no limits adopted for Euroscore II and for the TAVI indication for TAVI. Logistic Euroscores by procedure and type of instrument device are shown in Figures 6 and 7.

It can be established observed that procedures using the transapical and the subclavian approach for access procedures and procedures via a. subclavia are performed on patients with a somewhat higher estimated operative risk compared to transfemoral patients, which accords well with international experience.

Logistic Euroscores by centre in 2011 are shown in Table 1.

It seems reasonable to assume that the occurrence of aortic stenosis should be is relatively evenly spread across the country. However, there are rather large differences among counties regarding the number of TAVI/100 000 inhabitants that are performed, as is illustrated in Figure 8.

Symptoms

TAVI is intended both to prolong survival and to relieve symptoms. Symptomatology is often presented as NYHA class (New York Heart Association), which is a model for classifying the degree of heart failure, where class I is a symptom-free patient and class IV indicates complaints even at rest. Figure 9 shows the dominance of severely symptomatic patients among those treated.

Severity of the disease

The degree of severity is shown in Figures 10–11. It can be seen here that current guidelines for patient selection have been followed. Only patients with severe aortic stenosis have been treated.

Operation variables

Technical operation data are presented in Figures 12–14. It is gratifying to see that virtually all procedures are judged to be primarily successful. There does not seem to be any difference between types of procedure or between type of prosthesis. This accords well with data from previously published registry studies, which have reported technically successful implants in ca 98–99 % of the cases.

The fluoroscopy time is longer in transfemoral procedures, which is expected as fluoroscopy is needed also for the artery arterial puncture and other parts of the procedure. A tendency towards shorter fluoro-scopy times is discernible over the years.

Consumption of contrast media does not differ much across the types of procedures. Here, too,
a tendency can be seen towards less consumption of contrast media with time.

Data have emerged that indicate that even mild post-operative aortic insufficiency has a prognostically unfavourable effect regarding survival. Major efforts are being undertaken to develop methods to reduce paravalvular leakage (leakage around the outside of the valve prosthesis) in TAVI procedures. It is very common to see minimal leakage post-operatively, which is probably is of little prognostic significance. Fortunately, moderate leakage (≥2)degree II leakage or higher more occurred only to a very limited extent in our material
(Figure 15).

Complications

In the registry data reported, differences can be found in frequency of complications, owing partly to what access site used type of procedure was used and to some extent partly to what type of prosthesis was chosen. 30-day mortality has been around 12 % and risk of stroke around 3–4 %. However, later data have shown a declining frequency of stroke. Among product-specific complications, a higher frequency of newly arising need for a pacemaker has been reported when the CoreValve prosthesis was used.

Frequency of complications during the procedure and during the subsequent care period is presented in Tables 2–3. As previously, there is an increased need for a permanent pacemaker for CoreValve. Otherwise there are no noteworthy differences between the groups. It is natural to find more arterial complications in the CoreValve group as the majority of these procedures are transfemoral. Similarly, unplanned general anaesthesia is only applicable to CoreValve as the majority these procedures are (largely) done initially performed using only with local anaesthesia.

The low occurrence of stroke in 2011 is remarkable – a total of three patients (1.5 %).

Occurrence of stroke during the care period 2008–2011 is shown in Figure 16.

Only two patients required dialysis; the share with significant creatinine effect is shown in
Figure 17.

Survival

30-day and 1-year mortality is reported for all types of implants 2008–2011 (Figure 18–21). 30-day mortality among our patients is around 6.4 %, and 1-year mortality ca 15 %. These are highly viable figures internationally, and they indicate that Swedish TAVI activities are of high quality.

Figure 22 presents 1-year mortality by type of instrument. No difference is seen observed between the two types of prosthesis.

Follow-up

The registry also includes a follow-up of patients regarding prosthesis function and clinical parameters. A considerable lowering of NT-Pro BNP can be seen at follow-up after the procedure. Improvement can also be seen regarding distance walked in 6-minute walk tests. However, the patient group in question has many other complaints that significantly affect the distance walked, which renders this more difficult to interpret (Figures 23–24).

The most elderly

This year’s SWEDEHEART is focusing on characterising the giving an account of what treatment extended to our of our oldest patients, > 80 years, looks like. As the TAVI Registry primarily consists of registrations of elderly patients, no real comparison can be made to younger patients.such grouping has been done. Instead, outcomes are reported for patients aged 90 years or older. A total of 17 patients were treated in 2011 (Figure 25). From the beginning of 2008, 40 patients were followed up regarding 30-day mortality. At 30 days, two patients had died, corresponding to 5 % (Table 4). Regarding 1-year mortality, 23 patients were followed, one of whom died, representing 4.4 % (Table 5). This patient group is not the most common, but with correct patient selection they can be treated with low risk.