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Transcatheter aortic valve implantation: indications

Transcatheter aortic valve implantation (TAVI) has developed rapidly since the first-in-man implantation performed by Alain Cribier in Rouen in 2002. This new approach for the treatment of symptomatic patients with severe aortic stenosis (AS) has been shown to be feasible and safe in patients at very high or prohibitive surgical risk. The procedure should only be performed in hospitals with cardiac surgery on-site. The indication should be decided by a multidisciplinary heart valve team. As TAVI is currently only considered in high-risk patients, risk assessment is mandatory and consists in predicting the risk of the intervention by the STS and/or EuroSCORE II, and considering procedure impediment, major organ compromise and the frailty of the patient. Candidates are symptomatic; severe AS needs to be established (stage D according to the 2014 AHA/ACC valvular heart disease guidelines). Eligible patients should have a life expectancy of more than one year. The decision should be individualized. High-risk surgery corresponds to a EuroSCORE II >15-20% or STS score >8-10%.

TAVI is not recommended in patients with comorbidities precluding a significant benefit from the intervention.

Invasive and Interventional Cardiology, Cardiovascular Surgery


Introduction

After several years of animal studies, the first in vivo transluminal aortic valve implantation (TAVI) was performed by Alain Cribier in Rouen in 2002 [1]. The procedure is feasible and safe. The success rate is high. The possible procedure-related complications are stroke, need for a new pacemaker (more frequently for the self-expanding system than for the balloon-expandable system) and paravalvular regurgitation which, when moderate to severe, is associated with a higher mortality rate [2]. Currently, TAVI is indicated in patients considered not suitable for aortic valve replacement. Ongoing studies will evaluate whether the procedure is indicated in patients with intermediate risk. Guideline updates require appropriately designed and executed studies providing significant results.

Confirmation of severe aortic stenosis

AS is considered to be severe when peak aortic velocity is >4 m/sec or mean pressure gradient is ≥40 mmHg [3] . Transvalvular pressure gradients are flow-dependent. A valve area <1.0 cm² is considered severe and should be indexed to body surface area (cut-off value <0.6 cm²/m²) in patients with a small body surface area. In patients with low-flow, severe AS can be present with lower velocities and lower valve gradients. In the presence of symptomatic severe low-flow/low-gradient and reduced left ventricular ejection fraction (LVEF), dobutamine echocardiography should be performed at low to moderate doses (up to 20 µg/kg/min). An aortic valve area ≤1.0 cm² with peak velocity ≥4 m/sec at any flow rate confirms severe AS. This implies the presence of contractile reserve, defined as a >20% increase in stroke volume [4] . In the absence of contractile or flow reserve, the severity of AS is more difficult to ascertain [5] . If dobutamine induces an increase in valve area with no or minimal increase in mean gradient, the patient has pseudo-severe AS and should not be submitted to an intervention for valve disease. Patients with low-gradient and normal LVEF called paradoxical low-flow (stroke volume index <35 ml/m²), low-gradient severe AS have a guarded prognosis in the absence of surgical aortic valve replacement [6] . Severity is confirmed by an increased LV relative wall thickness, small LV dimensions, high BNP values and severe calcifications of the valve, easily quantitated with computed tomography. It is important to remember that the aortic valve calcium score suggesting severe AS is different in men and women, >2,065 AV and >1,275 AV, respectively.

The major pitfall in the assessment of AS severity is an underestimation of stroke volume and thus aortic valve area by the continuity equation which implies a circular LV outflow tract. LV outflow tract is, however, frequently oval and the minor dimension is measured by echocardiography. An underestimation of the diameter is squared in the continuity equation. Other imaging studies may be useful, such as three-dimensional echocardiography, computed tomography or cardiac magnetic resonance imaging.

Risk assessment

Risk assessment should combine risk estimates, procedure impediment, major organ dysfunction and frailty. An STS score >8-10% or a EuroSCORE II >15-20% indicates high risk. However, the EuroSCORE has been shown to overestimate the risk of aortic valve replacement but it is still the scoring system of choice according to the ESC/EACTS guidelines of 2012 [7] . The parameters used to calculate and predict risk are indicated in Table 1. However, none of the risk scores was designed for candidates of TAVI. Current surgical risks correlate poorly with the observed outcome of patients undergoing TAVI, even for the transapical approach [8] . Other models are available, such as the university health system consortium (UHC) which demonstrates better performance for postoperative complications after surgery but should not be used for TAVI indications [9].

Table 1. Patient-related factors in risk scores.

STS

Aortic valve replacement

(with or without coronary artery bypass grafting)

Procedure type

Ejection fraction

Age, sex, height, weight, race

Creatinine level

Heart failure

Symptoms at the time of admission and at time of surgery

Prior myocardial infarction

Arrhythmias

Chronic lung disease

Cerebrovascular disease

Peripheral arterial disease

Immunocompromised status

Diabetes, hypertension

Coronary anatomy

Risk factors for endocarditis

Resuscitation

Cardiogenic shock

Intra-aortic balloon pump

Valve disease

Mitral tricuspid and aortic insufficiency

Inotrope previous cardiac intervention

First cardiovascular surgery or reoperation

 

EuroSCORE II

Age, gender

Renal impairment

Extracardiac arteriopathy

Poor mobility

Chronic lung disease

Previous cardiac surgery

Diabetes on insulin

Critical preoperative state

Active endocarditis

Pulmonary hypertension and operation related factors: urgency, weight of the intervention

Left ventricular function

Myocardial association class

Surgery on thoracic aorta

Recent myocardial infarction

Canadian Cardiovascular Society class IV angina

Procedure impediment may represent an indication for TAVI even if the risk scores are not very high - heavily calcified ascending aorta, porcelain aorta, mediastinal radiation damage or coronary bypass grafts [10] . Major organ compromise includes severe cardiac dysfunction, severe chronic obstructive pulmonary disease with forced expiratory volume <1 L/s, renal failure ≥ stage 3, cancer, liver cirrhosis and cerebral dysfunction.

Several frailty indices are available to determine whether frailty is moderate to severe.

Frailty is not captured by the STS or EuroSCORE. Frailty indices predict surgical outcome [11], weight loss ≥10 pounds in the last year, decreased grip strength, exhaustion, low activity (weekly kilocaloric expenditure in the lowest 20th percentile for their gender [men <383 kcal/week; women <270 kcal/week]), slowed walking speed (walking speed <20th percentile, adjusted for gender and height [men: height and walk time ≤173 cm and ≥7 seconds or >173 cm and ≥6 seconds; women: ≤159 cm and ≥7 seconds or >159 cm and ≥6 seconds, respectively]). Other parameters can also be used: grip strength, standing balance, serum albumin [12] . Gait speed and STS score together predict outcome after surgery [13] .

TAVI has been shown to be superior to medical treatment in patients not suitable for surgery [14] and not inferior to surgical aortic valve replacement in high-risk patients [15] .

The heart team and heart valve clinic

The management of elderly patients with severe symptomatic AS should be decided by a Heart Team, including a cardiologist, a valve interventionalist, a cardiac surgeon, an imaging specialist, anesthesiologists, geriatricians and intensive care specialists. The patient, the family and the patient’s physician should be clearly educated by the Heart Team when several options for treatment are possible [7,10] .

Heart valve clinics and centers of excellence have developed. In the heart valve clinic the patient is evaluated by a cardiologist who is an expert in valvular heart diseases and who can select the appropriate tests required for the individual patient, e.g., imaging techniques, biological tests including renal function, coagulation status, natriuretic peptides. The patient is educated; follow-up and preoperative exams are organized [16] . The Heart Team integrates all information for an appropriate proposal.

Indications for TAVI

The recommendations produced by European and American guidelines are rather similar [7,10] . Both sets of guidelines indicate that a decision should be made by the multidisciplinary Heart Team. TAVI should only be performed in hospitals with cardiac surgery on-site. The European and American recommendations are indicated in Table 2.

Table 2. Indications for TAVI according to the ESC/EACTS and ACC/AHA guidelines.

ESC/EACTS

ACC/AHA

TAVI should only be undertaken with a multidisciplinary Heart Team

I C

When TAVR or high-risk surgical AVR is considered, members of a Heart Team should collaborate

I C

TAVI should only be performed in hospitals with cardiac surgery on-site

I C

 

 

TAVI is indicated in patients with severe symptomatic AS who are not suitable for AVR, have a >1-year life expectancy and are likely to gain improvement in quality of life

I B

TAVR is recommended in patients who meet an indication of intervention for AS who have a prohibitive surgical risk and a predicted post TAVR survival >12 months

I B

TAVI should be considered in high-risk patients with symptomatic AS who may still be suitable for surgery but in whom TAVI is favored by the Heart Team

IIa B

TAVR is a reasonable alternative to surgery in patients who meet an indication for AVR and who have a high surgical risk

IIa B

ACC: American College of Cardiology; AHA: American Heart Association; AS: aortic stenosis; EACTS: European Association for Cardio-Thoracic Surgery; ESC: European Society of Cardiology; TAVI: transcatheter aortic valve implantation; TAVR: transcatheter aortic valve replacement

Adapted from Vahanian et al (Eur Heart J 2012) and Nishimura et al (JACC 2014).

Contraindications for TAVI

The European guidelines indicate that absolute and relative contraindications, both clinical and anatomical, should be identified [7] .

Absolute contraindications

Absolute contraindications include the absence of a Heart Team and no cardiac surgery on-site, appropriateness of TAVI not confirmed by the Heart Team, estimated life expectancy <1 year, comorbidity suggesting lack of improvement of quality of life, inadequate annulus size (<18 mm, >29 mm), active endocarditis, symmetric valve calcification, short distance between the annulus and the coronary ostium, and plaques with mobile thrombi in the ascending aorta.

Relative contraindications

Relative contraindications include inadequate vascular access for transfemoral or subclavian approach (such patients could be treated from the transapical approach), bicuspid valve (no longer applicable), haemodynamic instability, and severe LV dysfunction.

TAVI in intermediate-risk patients

Current guidelines do not yet recommend TAVI in intermediate-risk patients. Randomized studies are ongoing: the SURTAVI trial, PARTNER II trial (intermediate-risk cohort). The BERMUDA trial tested propensity-matched cohorts: the 1-year mortality was similar in patients submitted to TAVI (16.5%) or aortic valve replacement (16.9%) (hazard ratio with 95% confidence interval: 0.9 [0.57-1.42]; p=0.64) [17] . An important finding was that, during the course of the study, the matched STS fell from 6% to 4.3%. The Bern low-intermediate risk study showed a low 1-year mortality in intermediate (3-8) STS patients (16.1%), whereas the low STS (<3) patients had a 10.1% mortality and the high STS (>8) patients had a 34.5% mortality (low vs. high: relative risk=0.27 [0.09-0.77]; intermediate vs. high: relative risk=0.41 [0.24-0.67], p<0.001 for both) [18] .

Conclusions

The European guidelines will be updated. The results of ongoing studies could potentially widen the indications for TAVI to include patients with intermediate risk. However, many centers have already adopted TAVI in patients at intermediate risk in daily practice. Circumspection is needed with respect to terminal, irreversible diseases.

References


  1. Cribier A, Eltchaninoff H, Bash A, Borenstein N, Tron C, Bauer F, Derumeaux G, Anselme F, Laborde F, Leon MB. Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description. Circulation. 2002;106(24):3006-8.
  2. Kodali SK, Williams MR, Smith CR, Svensson LG, Webb JG, Makkar RR, Fontana GP, Dewey TM, Thourani VH, Pichard AD, Fischbein M, Szeto WY, Lim S, Greason KL, Teirstein PS, Malaisrie SC, Douglas PS, Hahn RT, Whisenant B, Zajarias A, Wang D, Akin JJ, Anderson WN, Leon MB; PARTNER Trial Investigators. Two-year outcomes after transcatheter or surgical aortic-valve replacement. N Engl J Med. 2012;366(18):1686-95.
  3. Baumgartner H, Hung J, Bermejo J, Chambers JB, Evangelista A, Griffin BP, Iung B, Otto CM, Pellikka PA, Quiñones M; EAE/ASE. Echocardiographic assessment of valve stenosis: EAE/ASE recommendations for clinical practice. Eur J Echocardiogr. 2009;10(1):1-25.
  4. Monin JL, Monchi M, Gest V, Duval-Moulin AM, Dubois-Rande JL, Gueret P. Aortic stenosis with severe left ventricular dysfunction and low transvalvular pressure gradients: risk stratification by low-dose dobutamine echocardiography. J Am Coll Cardiol. 2001;37(8):2101-7.
  5. Monin JL, Quere JP, Monchi M, Petit H, Baleynaud S, Chauvel C, Pop C, Ohlmann P, Lelguen C, Dehant P, Tribouilloy C, Guéret P. Low-gradient aortic stenosis: operative risk stratification and predictors for long-term outcome: a multicenter study using dobutamine stress hemodynamics. Circulation. 2003;108(3):319-24.
  6. Clavel MA, Fuchs C, Burwash IG, Mundigler G, Dumesnil JG, Baumgartner H, Bergler-Klein J, Beanlands RS, Mathieu P, Magne J, Pibarot P. Predictors of outcomes in low-flow, low-gradient aortic stenosis: results of the multicenter TOPAS Study. Circulation. 2008;118(14 Suppl):S234-42.
  7. Joint Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology (ESC); European Association for Cardio-Thoracic Surgery (EACTS), Vahanian A, Alfieri O, Andreotti F, Antunes MJ, Barón-Esquivias G, Baumgartner H, Borger MA, Carrel TP, De Bonis M, Evangelista A, Falk V, Iung B, Lancellotti P, Pierard L, Price S, Schäfers HJ, Schuler G, Stepinska J, Swedberg K, Takkenberg J, Von Oppell UO, Windecker S, Zamorano JL, Zembala M. Guidelines on the management of valvular heart disease (version 2012). Eur Heart J. 2012;33(19):2451-96.
  8. Osswald BR, Gegouskov V, Badowski-Zyla D, Tochtermann U, Thomas G, Hagl S, Blackstone EH. Overestimation of aortic valve replacement risk by EuroSCORE: implications for percutaneous valve replacement. Eur Heart J. 2009;30(1):74-80.
  9. Kozower BD, Ailawadi G, Jones DR, Pates RD, Lau CL, Kron IL, Stukenborg GJ. Predicted risk of mortality models: surgeons need to understand limitations of the University HealthSystem Consortium models. J Am Coll Surg. 2009;209(5):551-6.
  10. Nishimura RA, Otto CM, Bonow RO, Carabello BA, Erwin JP 3rd, Guyton RA, O'Gara PT, Ruiz CE, Skubas NJ, Sorajja P, Sundt TM 3rd, Thomas JD; American College of Cardiology/American Heart Association Task Force on Practice Guidelines. 2014 AHA/ACC guideline for the management of patients with valvular heart disease: executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. J Am Coll Cardiol. 2014;63(22):2438-88.
  11. Makary MA, Segev DL, Pronovost PJ, Syin D, Bandeen-Roche K, Patel P, Takenaga R, Devgan L, Holzmueller CG, Tian J, Fried LP. Frailty as a predictor of surgical outcomes in older patients. J Am Coll Surg. 2010;210(6):901-8.
  12. Sundermann S, Dademasch A, Praetorius J, Kempfert J, Dewey T, Falk V, Mohr FW, Walther T. Comprehensive assessment of frailty for elderly high-risk patients undergoing cardiac surgery. Eur J Cardiothorac Surg. 2011;39(1):33-7.
  13. Afilalo J, Eisenberg MJ, Morin JF, Bergman H, Monette J, Noiseux N, Perrault LP, Alexander KP, Langlois Y, Dendukuri N, Chamoun P, Kasparian G, Robichaud S, Gharacholou SM, Boivin JF. Gait speed as an incremental predictor of mortality and major morbidity in elderly patients undergoing cardiac surgery. J Am Coll Cardiol. 2010;56(20):1668-76.
  14. Leon MB, Smith CR, Mack M, Miller DC, Moses JW, Svensson LG, Tuzcu EM, Webb JG, Fontana GP, Makkar RR, Brown DL, Block PC, Guyton RA, Pichard AD, Bavaria JE, Herrmann HC, Douglas PS, Petersen JL, Akin JJ, Anderson WN, Wang D, Pocock S; PARTNER Trial Investigators. Transcatheter aortic-valve implantation for aortic stenosis in patients who cannot undergo surgery. N Engl J Med. 2010;363(17):1597-607.
  15. Smith CR, Leon MB, Mack MJ, Miller DC, Moses JW, Svensson LG, Tuzcu EM, Webb JG, Fontana GP, Makkar RR, Williams M, Dewey T, Kapadia S, Babaliaros V, Thourani VH, Corso P, Pichard AD, Bavaria JE, Herrmann HC, Akin JJ, Anderson WN, Wang D, Pocock SJ; PARTNER Trial Investigators. Transcatheter versus surgical aortic-valve replacement in high-risk patients. N Engl J Med. 2011;364(23):2187-98.
  16. Lancellotti P, Rosenhek R, Pibarot P, Iung B, Otto CM, Tornos P, Donal E, Prendergast B, Magne J, La Canna G, Piérard LA, Maurer G. ESC Working Group on Valvular Heart Disease position paper--heart valve clinics: organization, structure, and experiences. Eur Heart J. 2013;34(21):1597-606.
  17. Piazza N, Kalesan B, van Mieghem N, Head S, Wenaweser P, Carrel TP, Bleiziffer S, de Jaegere PP, Gahl B, Anderson RH, Kappetein AP, Lange R, Serruys PW, Windecker S, Jüni P. A 3-center comparison of 1-year mortality outcomes between transcatheter aortic valve implantation and surgical aortic valve replacement on the basis of propensity score matching among intermediate-risk surgical patients. JACC Cardiovasc Interv. 2013;6(5):443-51.
  18. Wenaweser P, Stortecky S, Schwander S, Heg D, Huber C, Pilgrim T, Gloekler S, O'Sullivan CJ, Meier B, Jüni P, Carrel T, Windecker S. Clinical outcomes of patients with estimated low or intermediate surgical risk undergoing transcatheter aortic valve implantation. Eur Heart J. 2013;34(25):1894-905.

Notes to editor


Author:

Professor Luc A. Pierard, MD, PhD, FESC

Professor of Medicine Liège University,

Head of Cardiology Department,

CHU Sart Tilman,

Domaine Universitaire du Sart Tilman B35,

B-4000 Liege,

Belgium

Tel: + 32.4.366.71.94

E-mail: lpierard@chu.ulg.ac.be

Author disclosures: The author declares there is no conflict of interest regarding the matter and material of this article.

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.