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Heart Online First, published on June 29, 2015 as 10.1136/heartjnl-2014-307008 Education in Heart
TAVI in 2015: who, where and how? Neil Ruparelia,1,2 Bernard D Prendergast3 ▸ Additional material is published online. To view please visit the journal (http:// dx.doi.org/10.1136/heartjnl2014-307008)
CURRICULUM TOPIC
1
INTRODUCTION
Oxford Heart Centre, John Radcliffe Hospital, Oxford, UK Hammersmith Hospital, London, UK 3 St Thomas’ Hospital, London, UK Correspondence to Dr Bernard D Prendergast, St Thomas’ Hospital, Westminster Bridge Road, London, SE1 7EH. UK; bernard. [email protected]
Invasive imaging: angiography.
cardiac
catherisation
and
Aortic stenosis (AS) is the most common valvular pathology in the elderly and prevalence is estimated at 4.6% in patients greater than 75 years of age.1 As the ageing population expands this is projected to increase rapidly in forthcoming decades.2 The majority of patients remain asymptomatic for many years and AS is associated with a low mortality risk in this setting.3 However, patients with severe AS who develop symptoms have very poor prognosis with significant reduction in survival and a 50% mortality within 2 years without treatment.4 Surgical aortic valve replacement (SAVR) has been the gold standard treatment for AS over the past 50 years. Careful patient selection, improved operative techniques and advances in valve design have resulted in excellent outcomes in contemporary series.5 6 However, in spite of these advances, SAVR is associated with a 5–10% risk of major adverse perioperative events and a mortality of up to 20% at 1 year7 8 in elderly patients. Consequently, a significant proportion of individuals are not offered or do not undergo SAVR and are managed conservatively with very poor outlook. The emergence of transcatheter aortic valve implantation (TAVI) has revolutionised the treatment of symptomatic severe AS. Following ex vivo and in vivo testing,9 the first human procedure was undertaken by Cribier and colleagues in 200210 via an antegrade trans-septal approach. Subsequently, a number of registries,11 12 and randomised controlled trials,13–18 have demonstrated significant benefits of TAVI in inoperable and high-risk surgical candidates. To date, over 100 000 TAVI procedures have been performed worldwide. Within this article, we aim to discuss the contemporary status of TAVI, current indications, patient selection and other applications of this technology.
CURRENT STATUS OF TAVI Evidence
To cite: Ruparelia N, Prendergast BD. Heart Published Online First: [please include Day Month Year] doi:10.1136/heartjnl2014-307008
The first successful TAVI procedure10 demonstrated the feasibility of this treatment approach for the management of symptomatic severe AS and was subsequently confirmed by many single- and multicentre registries.11 19–21 The Placement of AoRTic TraNscathetER valves (PARTNER) I trial13 14 was the first large randomised study conducted to test the efficacy of TAVI using the balloon-expandable (BE) Edwards Sapien valve. High-risk surgical candidates were randomised to either SAVR or TAVI (Cohort A), while individuals deemed inoperable were randomised to TAVI or medical therapy (Cohort B).
Learning objectives ▸ To understand the current indications for transcatheter aortic valve implantation. ▸ To appreciate the importance of appropriate patient selection and the central role of the ‘Heart Team’. ▸ To understand the current limitations of transcatheter aortic valve implantation. The PARTNER I Cohort B trial randomised patients to TAVI (n=179) or standard medical therapy (n=179) including the use of balloon valvuloplasty if indicated.14 TAVI resulted in a significant reduction in 1-year mortality (30.7% vs 50.1%), which was sustained at 2- (43.3% vs 68%)17 and 3-year follow-up (54.1% vs 80.9%).18 Long-term 5-year follow-up data have been recently presented demonstrating the superiority of TAVI over medical therapy with a mortality rate of 71.8% in the TAVI group compared with 93.6% in controls.22 These findings were supported by the recent Medtronic CoreValve US Pivotal Trial, where TAVI using the self-expandable (SE) Medtronic CoreValve was associated with a 40% reduction in the combined endpoint of all-cause mortality and stroke at 1 year in the ‘extreme risk’ arm.15 In PARTNER I Cohort A, TAVI was compared with SAVR in 699 high-risk surgical candidates randomized to TAVI (n=348) or SAVR (n=351). All-cause mortality was slightly lower with TAVI at 30 days (3.4% vs 6.5%, p=0.07) but comparable at 113 (24.2% vs 26.8%), 2 (33.9% vs 35%)16 and 3-year (44.2% vs 44%) follow-up. Although there were more vascular complications reported in the TAVI group at 30 days (11% vs 3%, p10%) have been used to identify ‘high-risk’ patients. However, it is increasingly apparent that these scores have their limitations and are poorly predictive of mortality in the TAVI setting.28 Moreover, factors such as patient frailty which have been demonstrated to be associated with adverse outcomes are not incorporated within current models.29 A broad range of factors
contribute to patient frailty30 and a number of different scores have been developed to reflect these (table 2). However, these assessments are complex and time consuming with limitations imposed by a large element of subjectivity when assessing patients. Nonetheless, frailty is an important aspect of patient screening and should be part of formal assessment by the ‘Heart Team’ in conjunction with more established surgical risk scores when determining the best treatment strategy.
PATIENT SCREENING It is imperative that appropriate investigations are performed to assess anatomical and functional characteristics which assess the suitability for TAVI (or contraindication for conventional surgery) (table 3). Many (or all) of these investigations can be carried out either by the referring team or within the TAVI centre. However, it is critically important that all of these investigations are available to the ‘Heart Team’ when making an informed decision with regards to the suitability of a patient for TAVI.
ANATOMICAL ASSESSMENT Transthoracic echocardiography, transoesophageal echocardiography (TOE) and CT are complementary imaging techniques used to evaluate aortic valve function and anatomy. In addition to confirmation of AS, identification of valve anatomy (bicuspid/tricuspid), presence and distribution of calcium and assessment of aortic annular dimensions are important when determining the suitability of TAVI. Left and right ventricular function, associated valve disease, the presence of left ventricular thrombus or outflow obstruction and the distance between the aortic annulus and coronary ostia are fundamental to appropriate patient, device and vascular access site selection (figure 1A).
Table 2 Frailty risk scores McArthur study of successful aging
Motor fitness scale
Fried frailty score
Comprehensive assessment of frailty
▸ ▸ ▸ ▸
▸ ▸ ▸ ▸ ▸
▸ ▸ ▸ ▸ ▸
▸ ▸ ▸ ▸ ▸ ▸
Grip strength >16 kg Low levels of physical activity 6 min walk 5 kg in year Get up an go >17 s MMSE
Heart Online First, published on June 29, 2015 as 10.1136/heartjnl-2014-307008 Education in Heart
TAVI in 2015: who, where and how? Neil Ruparelia,1,2 Bernard D Prendergast3 ▸ Additional material is published online. To view please visit the journal (http:// dx.doi.org/10.1136/heartjnl2014-307008)
CURRICULUM TOPIC
1
INTRODUCTION
Oxford Heart Centre, John Radcliffe Hospital, Oxford, UK Hammersmith Hospital, London, UK 3 St Thomas’ Hospital, London, UK Correspondence to Dr Bernard D Prendergast, St Thomas’ Hospital, Westminster Bridge Road, London, SE1 7EH. UK; bernard. [email protected]
Invasive imaging: angiography.
cardiac
catherisation
and
Aortic stenosis (AS) is the most common valvular pathology in the elderly and prevalence is estimated at 4.6% in patients greater than 75 years of age.1 As the ageing population expands this is projected to increase rapidly in forthcoming decades.2 The majority of patients remain asymptomatic for many years and AS is associated with a low mortality risk in this setting.3 However, patients with severe AS who develop symptoms have very poor prognosis with significant reduction in survival and a 50% mortality within 2 years without treatment.4 Surgical aortic valve replacement (SAVR) has been the gold standard treatment for AS over the past 50 years. Careful patient selection, improved operative techniques and advances in valve design have resulted in excellent outcomes in contemporary series.5 6 However, in spite of these advances, SAVR is associated with a 5–10% risk of major adverse perioperative events and a mortality of up to 20% at 1 year7 8 in elderly patients. Consequently, a significant proportion of individuals are not offered or do not undergo SAVR and are managed conservatively with very poor outlook. The emergence of transcatheter aortic valve implantation (TAVI) has revolutionised the treatment of symptomatic severe AS. Following ex vivo and in vivo testing,9 the first human procedure was undertaken by Cribier and colleagues in 200210 via an antegrade trans-septal approach. Subsequently, a number of registries,11 12 and randomised controlled trials,13–18 have demonstrated significant benefits of TAVI in inoperable and high-risk surgical candidates. To date, over 100 000 TAVI procedures have been performed worldwide. Within this article, we aim to discuss the contemporary status of TAVI, current indications, patient selection and other applications of this technology.
CURRENT STATUS OF TAVI Evidence
To cite: Ruparelia N, Prendergast BD. Heart Published Online First: [please include Day Month Year] doi:10.1136/heartjnl2014-307008
The first successful TAVI procedure10 demonstrated the feasibility of this treatment approach for the management of symptomatic severe AS and was subsequently confirmed by many single- and multicentre registries.11 19–21 The Placement of AoRTic TraNscathetER valves (PARTNER) I trial13 14 was the first large randomised study conducted to test the efficacy of TAVI using the balloon-expandable (BE) Edwards Sapien valve. High-risk surgical candidates were randomised to either SAVR or TAVI (Cohort A), while individuals deemed inoperable were randomised to TAVI or medical therapy (Cohort B).
Learning objectives ▸ To understand the current indications for transcatheter aortic valve implantation. ▸ To appreciate the importance of appropriate patient selection and the central role of the ‘Heart Team’. ▸ To understand the current limitations of transcatheter aortic valve implantation. The PARTNER I Cohort B trial randomised patients to TAVI (n=179) or standard medical therapy (n=179) including the use of balloon valvuloplasty if indicated.14 TAVI resulted in a significant reduction in 1-year mortality (30.7% vs 50.1%), which was sustained at 2- (43.3% vs 68%)17 and 3-year follow-up (54.1% vs 80.9%).18 Long-term 5-year follow-up data have been recently presented demonstrating the superiority of TAVI over medical therapy with a mortality rate of 71.8% in the TAVI group compared with 93.6% in controls.22 These findings were supported by the recent Medtronic CoreValve US Pivotal Trial, where TAVI using the self-expandable (SE) Medtronic CoreValve was associated with a 40% reduction in the combined endpoint of all-cause mortality and stroke at 1 year in the ‘extreme risk’ arm.15 In PARTNER I Cohort A, TAVI was compared with SAVR in 699 high-risk surgical candidates randomized to TAVI (n=348) or SAVR (n=351). All-cause mortality was slightly lower with TAVI at 30 days (3.4% vs 6.5%, p=0.07) but comparable at 113 (24.2% vs 26.8%), 2 (33.9% vs 35%)16 and 3-year (44.2% vs 44%) follow-up. Although there were more vascular complications reported in the TAVI group at 30 days (11% vs 3%, p10%) have been used to identify ‘high-risk’ patients. However, it is increasingly apparent that these scores have their limitations and are poorly predictive of mortality in the TAVI setting.28 Moreover, factors such as patient frailty which have been demonstrated to be associated with adverse outcomes are not incorporated within current models.29 A broad range of factors
contribute to patient frailty30 and a number of different scores have been developed to reflect these (table 2). However, these assessments are complex and time consuming with limitations imposed by a large element of subjectivity when assessing patients. Nonetheless, frailty is an important aspect of patient screening and should be part of formal assessment by the ‘Heart Team’ in conjunction with more established surgical risk scores when determining the best treatment strategy.
PATIENT SCREENING It is imperative that appropriate investigations are performed to assess anatomical and functional characteristics which assess the suitability for TAVI (or contraindication for conventional surgery) (table 3). Many (or all) of these investigations can be carried out either by the referring team or within the TAVI centre. However, it is critically important that all of these investigations are available to the ‘Heart Team’ when making an informed decision with regards to the suitability of a patient for TAVI.
ANATOMICAL ASSESSMENT Transthoracic echocardiography, transoesophageal echocardiography (TOE) and CT are complementary imaging techniques used to evaluate aortic valve function and anatomy. In addition to confirmation of AS, identification of valve anatomy (bicuspid/tricuspid), presence and distribution of calcium and assessment of aortic annular dimensions are important when determining the suitability of TAVI. Left and right ventricular function, associated valve disease, the presence of left ventricular thrombus or outflow obstruction and the distance between the aortic annulus and coronary ostia are fundamental to appropriate patient, device and vascular access site selection (figure 1A).
Table 2 Frailty risk scores McArthur study of successful aging
Motor fitness scale
Fried frailty score
Comprehensive assessment of frailty
▸ ▸ ▸ ▸
▸ ▸ ▸ ▸ ▸
▸ ▸ ▸ ▸ ▸
▸ ▸ ▸ ▸ ▸ ▸
Grip strength >16 kg Low levels of physical activity 6 min walk 5 kg in year Get up an go >17 s MMSE
