when is it too late for aortic valve · pdf filewhen is it too late for aortic valve surgery...

AORTIC VALVE SURGERY | REVIEW

Aortic stenosis

(AS) is currently the most common cause of AS in adults and the most frequent reason for aor-tic valve replacement (AVR) in these patients. Its incidence is on the rise since this pathology is a disease of ageing and the population is get-ting older.1 The natural history of AS has shown that in the absence of surgical management the patient develops progressive invalidating symptoms of syncope and angina. The mortality

-tively, from congestive heart failure.2 Indication for surgery arises when the severity of the ste-

0.6 cm²/m² body surface area) or the patient be-comes symptomatic.3

Conventional surgical AVR is the reference treat-ment and is performed under cardiopulmonary bypass, cardiac arrest and aortic cross-clamping. The native cusps are excised and a prosthesis is sutured into the aortic annulus replacing the na-tive valve (Figure 1).

CORRESPONDENCE

Prof Nawwar Al-Attar, Department of Cardiac Surgery, Bichat Hospital, 46 rue Henri Huchard, 75018 Paris, France.

Tel : +33140257132Fax : +33140257229E-mail : [email protected]

ISSN 2042-4884

ABSTRACT

Determining operability in patients with aortic valve disease is dependent on two major factors: The extent of damage induced by strain on the myocardium from stenotic and regurgitant lesions and technical and anatomical considerations related to the surgical procedure itself. The decision to

intervention. Indications recommend performing corrective procedures before establishment of severe myocardial damage. Thus the treating physician may believe that it is too late to refer a

co-morbidities, and when myocardial contractile reserve is poor.

On the other hand, the surgeon may be reluctant to perform the intervention in the presence of technical challenges. In either case, management of valve disease has witnessed major advances permitting surgical intervention in these high-risk patients. Anaesthetic care has improved with perioperative and intensive care protocols allowing better preparation of patients for the surgical procedure and smoother postoperative periods. Surgical techniques have become less aggressive

better myocardial protection. Recently, transcatheter techniques allowing endovascular access precluding the need for cardiopulmonary bypass and aortic cross clamping altogether have opened new horizons in patients for whom technical complexity would contraindicate the procedure or the

centre experience, available technology and should be taken by a heart team including surgeons, cardiologists and anaesthesiologists.

When is it Too Late for Aortic Valve Surgery Nawwar Al-Attar, FRCS, FETCS, PhD & Patrick Nataf, FETCS, MDAssistance Publique-Hôpitaux de Paris (AP-HP), Department of Cardiac Surgery, Bichat – Claude Bernard Hospital, University Paris 7 Denis Diderot, Paris, France

Received 31/12/2010, Reviewed 10/1/2011, Accepted 18/01/2011Keywords: valve disease, percutaneous valve therapy, surgery-valveDOI: 10.5083/ejcm.20424884.25

Isolated AVR carries an average 30 day mortality of 3.8±1.5%.4 AVR is the “gold standard” treat-ment for symptomatic aortic stenosis and has shown to improve outcome and survival. Fol-lowing AVR and removal of the obstruction to

rapidly improves in part because the ventricle has been preconditioned to generate higher pressures. Thus, there are few contraindications to valve replacement for severe aortic stenosis when left ventricular function is not depressed.5

Moreover, the indications for intervention have been revised to perform corrective procedures before establishment of severe myocardial dam-age and according to some authors even prior to onset of symptoms.6 A multivariate analysis of almost 6,000 patients having AVR, showed

mortality were age≥80 years, NYHA class≥III, EF≤30% associated with previous MI, emergent AVR and concomitant coronary artery bypass graft (CABG) surgery.7

32 EUROPEAN JOURNAL OF CARDIOVASCULAR MEDICINE VOL I ISSUE III 33EUROPEAN JOURNAL OF CARDIOVASCULAR MEDICINE VOL I ISSUE III

Limits related to age:

Cardiologists are reluctant to refer elderly and high-risk patients for AVR. Age was a recurrent factor for refusing surgery for 31.8% of pa-tients with AS of the Euro Heart Survey on Valvular Heart Disease8 and 62% of patients with AS in another study from the USA.9 Ad-vanced age is an important predictor of operative risk and survival in cardiac surgery. It has repeatedly and consistently been shown to be a predictor of both poor in-hospital outcome and long-term survival.

In a series of 6,359 patients undergoing aortic valve replacement, Hannan et al. showed an incremental increase in the adjusted hazard ratio for 30-month survival from 1.57 to 2.18 to 3.96 in age ranges 65-74 y, 75-84 y and ≥85 y, respectively. After isolated AVR, the 30-month survival was 90.1% for patients of age <75 and 86.2% for patients >75 years of age.10 A study in octogenarians with severe AS showed that

survival rates of 87, 78 and 68%, respectively, compared with 52, 40 and 22%, respectively, in those who had no AVR.11 Elderly patients on the other hand experience increased operative mortality and also are at higher risk for valve-related events. 12,13

Nevertheless, age is not, per se, a contraindication to AVR according to published guidelines.3,14,15,16 Analysis of determinants of opera-tive mortality in regard to age showed that age is not linearly related to the mortality rate after AVR10,17 and there is considerable func-tional improvement after valve replacement.18

Limits related to comorbidity:

Additionally, patients can be refused surgery because of severe co-morbidities known to be associated with poor outcome. Since the prevalence of AS increases with age, and as longevity within the gen-eral population is increasing, the proportion of patients for whom surgery may be too late due to multiple comorbidities is also ex-pected to increase. These comorbidities may be related to concomi-tant cardiac diseases which further compromise myocardial function such as poor left ventricular ejection fraction (LVEF), previous cardiac surgery and associated coronary artery disease (CAD). Other comor-bidities related to the general condition of the patient such as neu-rological dysfunction, chronic lung disease, liver cirrhosis and renal

These patients are prone to severe postoperative complications as infections and bleeding; and the procedure itself may further com-promise vital organ function.10,19,20 The contribution of these fac-tors can increase the odds ratio for operative mortality by a factor of 10.6 for emergency versus elective surgery, 4.9 for renal failure, 3.1 for NYHA class (III-IV versus I-II) and 4.3 for neurological dysfunction.3 Thus it may too late to perform elective valve replacement on pa-tients with terminal end-organ failure of the liver (Child-Pugh class B or C cirrhosis) or lung.

Despite the increased risk with several comorbidities, survival in el-derly patients (≥80 years) with severe AS and low LVEF (≤30%) and/or chronic renal failure was still better in patients who had AVR as compared to those who did not.11

Limits related to presence of concomitant coronary artery disease:

due to the presence of a concomitant cardiac pathology and im-paired LV function from an ischaemic myocardium.12 Patients with acute myocardial infarction (AMI) <24 hours or who were haemody-namically unstable had a risk-adjusted 30-month survival of 59.6%, compared with 83.6% for patients with neither AMI <24 hours nor haemodynamic instability.10

has changed with patients presenting with several comorbidities particularly CAD, concomitant CABG and a greater incidence of left heart failure. The operative mortality of AVR doubles with the addi-tion of a concomitant CABG procedure which cannot be explained by the simple increment in cross clamping and cardiopulmonary by-pass times.7 Concomitant CABG had an adjusted 30-month mortal-ity hazard ratio of 1.26 in comparison with isolated AVR. After AVR, LV dimensions normalise more quickly in the group with isolated AVR compared to those with concomitant CABG further suggesting that CAD has a negative impact on postoperative myocardial recov-ery. The operative risk in patients with CAD requiring concomitant

cerebrovascular disease, peripheral vascular disease, extensive aortic atherosclerosis, diabetes and renal failure.10 Nevertheless, there is a consensus that the addition of CABG to AVR slightly improves long-term survival, even in high-risk populations.22

Limits related to contractile reserve:

Delay in the management of patients with AS may give rise to certain

after AVR. When the aortic valve area is less than half of normal, the gradient across the valve becomes important and the increased af-terload is associated with concentric myocardial hypertrophy which maintains systolic performance. The EF is decreased because of in-creased afterload and impaired diastolic function, but contractility is maintained and AVR has an excellent outcome with EF returning to normal values once the afterload excess is removed.23 However in other patients, hypertrophy fails to normalise wall stress causing the abnormal afterload to reduce ventricular ejection, reducing cardiac output, adding to the heart failure syndrome.24

This subset of patients with low gradient AS and low EF is known to be associated with poorer outcomes after AVR. It is seen in 5–10% of all cases of severe AS25 -dient <30 mmHg (or 40 mm Hg), an aortic valve area <1 cm², and an EF<35% (or 40%).21,22 In patients with low gradient and low car-diac output, there is severe decrease in EF in excess of what would have occurred through afterload increase alone.26 The associated myocardial dysfunction contributes to a poor prognosis. Since the transvalvular gradient is small, there is a correspondingly smaller re-duction in afterload and thus a smaller improvement in EF following surgery.27 AVR in this group of patients carries a poor prognosis with an operative mortality reported as high as 21% with a 50% death rate within four years of the procedure.28 Although AVR is superior to medical management in terms of short-term survival, surgery is not

of patients before surgery may decide whether medical or surgical therapy is best.

1) stenosis severity2) inotropic reserve3) the presence or absence of CAD or other valve disease, and 4) other comorbidities.

LIMITS OF SURGERY IN AORTIC VALVE DISEASE

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Figure 1: Conventional surgical aortic valve replacement is performed under cardiopulmonary bypass, cardiac arrest and aortic cross-clamping. The aorta is opened, the native valve is removed and the aortic annulus cleaned from remnants allowing suturing of a prosthesis (in this case, a bioprosthesis) into the aortic annulus. Insert: A severely calcified aortic valve causing stenosis.











































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HEALTHCARE BULLETIN | AORTIC VALVE SURGERY
























Patients without inotropic reserve and those with a large increase

from AVR and are generally considered a contraindication because of “pseudo-aortic stenosis”. Nevertheless, in a recent international multicentre registry of low EF/low gradient AS, AVR was associated with superior survival and was advocated when mean pressure gra-dient was >20 mm Hg and in the absence of excessive comorbidities or severe CAD with large scarring caused by extensive myocardial infarction. The authors conclude that the lack of contractile reserve in these patients may not systematically be related to irreversible LV dysfunction but probably due to an afterload mismatch that is not corrected by inotropic stimulation with dobutamine infusion.29

Technical limits to surgical AVR:

In addition to comorbidities, patients may present with technical -

form. This is particularly true in patients undergoing redo surgery with patent coronary artery bypass grafts, where the risk of injury to the graft during dissection can be prejudicious to myocardial vascularisation. The matter is further complicated by issues related to cardioplegia when the patent grafts are the internal thoracic ar-teries. Patients those with previous mediastinal radiotherapy and radiation damage to the myocardium are also known to have poor

-matous ascending aorta (porcelain aorta), cross clamping and aor-totomy can be impossible.

Since operative mortality is a standard parameter of operative suc-

good measure of quality of cardiac surgical care, as long as patient risk factors are taken into consideration, thus several risk scores have been described to calculating predicted operative mortality for patients undergoing cardiac surgery.30 The most employed sur-gical scores, namely the EuroSCORE31 and STS score32 -titative assessment to establish whether patients are at high risk

for this population, these scores do not capture all relevant vari-ables.15,33 Moreover they collect a large number of preoperative data that are not all incorporated in the calculation of predicted mortality. Thus out of more than 50 variables collected by the STS score, only 24 are actually used in its mortality algorithm for pa-tients having valve surgery.15 Variables such as hepatic disease, previous chest wall irradiation, nutritional status and frailty that can

STS risk algorithm. 34,35

Amber et al. described a risk model that can be applied to patients undergoing valve surgery, with or without concomitant CABG surgery based on data from the Great Britain and Ireland national cardiac surgical database.36 While scores are useful tools to predict operative mortality in a broad sense, clinical judgement and care-ful preoperative assessment of patients are the key determinants in decision making.

Transcatheter aortic valve implantation (TAVI) techniques

Transcatheter aortic valve implantation (TAVI) techniques have been developed to provide alternative approaches to patients for whom conventional AVR is fraught with a considerable risk (Figure 2). These techniques are performed without cardiopulmo-nary bypass or aortic cross clamping under general or locoregional

-raphy (TEE) guidance.

They have been performed via two distinct approaches, namely the transfemoral (TF) and transapical (TA) approaches with established feasibility and have been described in detail.37,38,39 Each approach has its advantages and the selection strategy of patients for one technique or the other depends on centre and physician prefer-ence.40

The decision for performing TAVI is considered in patients with severe symptomatic AS having: 41

• Contraindications to, or high risk for AVR

• Life expectancy >1 year

• Favourable anatomy for valve implantation

Patients undergo complete clinical examination, transthoracic echocardiography (TTE), TEE, coronary angiography, aortic and femoroiliac angiography and multislice computed tomography prior to surgery. This screening process is necessary to establish feasibility of TAVI and conformity of the aortic root geometry and anatomy. The contraindications for TAVI are listed in Table 1. Despite opening new horizons for patients refused or contraindicated con-ventional surgery, several questions remain unanswered concern-

leaks on survival, and LV function, and the incidence of endocarditis after TAVI.

I. Related to the aortic valve

1. Congenital aortic stenosis, unicuspid or bicuspid aortic valve 2. Non-valvular aortic stenosis 3. Aortic annulus <18mm or >27mm

II. Associated cardiac disease

1. Presence of intracardiac mass, thrombus or vegetation

requiring revascularisation3. Hypertrophic cardiomyopathy (HOCM) 4. Active bacterial endocarditis or other active infections

III. Related to the approach

A. TF approach

atheroma or diameter <6-7mm

3. Patients with bilateral iliofemoral bypasses 4. Severe angulation or aneurysm of the abdominal aorta with thrombosis

B. TA approach

1. Previous surgery of the LV

3. Non-reachable LV apex

Table 1: Contraindications and limits for TAVI






























A. TF approach



B. TA approach




Figure 2: Heavily calcified and atheromatous ascending (porcelain) aorta (arrows). Conventional AVR would be a considerable technical challenge and fraught with hazards. A transcatheter valve has been successfully inserted into the aortic annulus (asterisk).


LIMITS OF SURGERY IN AORTIC VALVE SURGERY






























A. TF approach



B. TA approach




REFERENCES



Otto CM, Lind BK, Kitzman DW, et al: Association of aortic valve sclerosis with cardiovascular mortality and morbidity in the elderly. N Engl J Med 1999; 341:142

Chizner MA, Pearle DL, deLeon Jr AC. The natural history of aortic stenosis in adults Am Heart J 1980;99:419-424. Vahanian A, Baumgartner H, Bax J, et al. Guidelines on the manage-ment of valvular heart disease. The Task Force on the management of valvular heart disease of the European Society of Cardiology. Eur Heart J 2007; 28: 230-268. STS National Database. STS US Cardiac Surgery Database: 1997 Aortic Valve Replacement Patients: Preoperative Risk Variables. Chicago: Society of Thoracic Surgeons; 2000. http://www.ctsnet.org/doc/3031 (accessed 30 Dec 2010). Akins, CW. Invited commentary. Ann Thorac Surg 2009;87:1749-1750. Mihaljevic T, Nowicki ER, Rajeswaran J, et al. Survival after valve replacement for aortic stenosis: implications for decision making. J Thorac Cardiovasc Surg. 2008;135:1270-8. . Nowicki ER, Birkmeyer NJ, Weintraub RW, et al; Northern New England Cardiovascular Disease Study Group and the Center for Evaluative Clinical Sciences, Dartmouth Medical School. Multivari-able prediction of in-hospital mortality associated with aortic and mitral valve surgery in Northern New England. Ann Thorac Surg. 2004;77:1966-77. Iung B, Baron G, Butchart EG, et al. A prospective survey of patients with valvular heart disease in Europe: The Euro Heart Survey on Valvular Heart Disease. Eur Heart J 2003;24:1231-1243. Varadarajan P, Kapoor N, Bansal RC, Pai RG. history of 453 nonsurgically managed patients with severe aortic stenosis. Ann Thorac Surg 2006;82:2111-2115. . Hannan EL, Samadashvili Z, Lahey SJ, et al. Aortic Valve Replacement for Patients With Severe Aortic Stenosis: Risk Factors and Their Impact on 30-Month Mortality. Ann. Thorac. Surg. 2009;87:1741-1749. Varadarajan P, Kapoor N, Bansal RC, et al. Survival in elderly patients with severe aortic stenosis is dramatically improved by aortic valve replacement: Results from a cohort of 277 patients aged > or =80 years. Eur J Cardiothorac Surg. 2006;30:722-7. Asimakopoulos G, Edwards MB, Taylor KM. Aortic valve replacement in patients 80 years of age and older: survival and cause of death based on 1100 cases: collective results from the UK Heart Valve Registry. Circulation. 1997 18;96:3403-8.

Dewey TM, Brown D, Ryan WH, et al. Reliability of risk algorithms in predicting early and late operative outcomes in high risk patients undergoing aortic valve replacement. J Thorac Cardiovasc Surg 2008;135:180-187

Alexander KP, Anstrom KJ, Muhlbaier LH, et al. Outcomes of cardiac surgery in patients age > 80 years: results from the National Cardiovascular Network. J Am Coll Cardiol 2000;35:731–8

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They have been performed via two distinct approaches, namely the transfemoral (TF) and transapical (TA) approaches with established feasibility and have been described in detail. 37,38,39 Each approach has its advantages and the selection strategy of patients for one technique or the other depends on centre and physician prefer-ence.40







Aortic regurgitation

In aortic regurgitation (AR), the main strain comes from volume overload on the LV increasing left ventricular work and leading to ventricular remodelling. Initially this allows the heart to cope with the increased load but will eventually lead to the development of heart failure. AVR improves LV function and forward cardiac output and is should be performed before LVEF falls below 50% or when end-systolic dimension increases above 55 mm. It may be too late in patients with extremely dilated LV with depressed LVEF to gain

hypertension in patients with severe AR also increases the surgical risk. However, AVR in patients with severe AR and LVEF<40% was

medical management.42 Likewise, AVR in patients with pulmonary hypertension was associated with an acceptable operative risk

better (62%) when compared to the conservatively treated group (22%).43

CONCLUSIONS

The prevalence of valvular heart disease is rising with the ageing -

ly by degenerative disease. Valve surgery is currently the reference treatment of stenotic and regurgitant lesions. However, if left un-treated severe valvular disease may lead to severe myocardial dam-age with poor ventricular function and loss of inotropic reserve and

-cal intervention may also been fraught with high risk in the pres-ence of several severe comorbidities or technical problems making the procedure hazardous. Advances in monitoring systems and perioperative pharmacological manipulation together with surgi-cal experience and novel transcatheter approaches push the limits of surgery and can further improve outcomes for selected patients with aortic valvular heart disease.



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CONCLUSIONS




REFERENCES (Continued)



Florath I, Rosendahl UP, Mortasawi A, et al. Current determinants of operative mortality in 1400 patients requiring aortic valve replacement. Ann Thorac Surg 2003;76:75– 83. Bonow RO, Carabello B, Chatterjee K, et al. ACC/AHA 2006 guidelines 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 (Writing Committee to Develop Guidelines for the Management of Patients with Valvular Heart Disease). Circulation 2006;114:e84 –231. Edwards MB, Taylor KM. Outcomes in nonagenarians after heart valve replacement operation. Ann Thorac Surg 2003;75:830-834. Florath I, Albert A, Rosendahl U, et al. Mid term outcome and quality of life after aortic valve replacement in elderly people: mechanical versus stentless biological valves. Heart. 2005;91:1023-9. Bouma BJ, van Den Brink RB, Zwinderman K, et al.

surgical treatment? An aid to clinical decision making. J Heart Valve Disease 2004;13:374–81. Iung B, Cachier A, Baron G, et al. Decision making in elderly patients with severe aortic stenosis : Why are so many denied surgery? Eur Heart J 2005; 26: 2714-2720. Langanay T, De Latour B, Ligier K, et al. Surgery for aortic stenosis in

on hospital mortality. J Heart Valve Dis. 2004;13:545-52 Kobayashi KJ, Williams JA, Nwakanma L, et al. Aortic Valve Replacement and Concomitant Coronary Artery Bypass: Assessing the Impact of Multiple Grafts. Ann Thorac Surg, 2007;83:969-978. Huber D, Grimm J, Koch R, et al. Determinants of ejection performance in aortic stenosis. Circulation 1981;64:126–34. Carabello BA, Paulus WJ. Aortic stenosis. Lancet. 2009 14;373:956-66. Levy F, Laurent M, Monin JL, et al. Aortic valve replacement for

long-term outcome: a European multicenter study. J Am Coll Cardiol 2008;51:1466–72. Carabello BA, Green LH, Grossman W, et al. Hemodynamic determinants of prognosis of aortic valve replacement in critical aortic stenosis and advanced congestive heart failure. Circulation 1980;62:4208. Carabello BA. Is it ever too late to operate on the patient with valvular heart disease? J Am Coll Cardiol. 2004 21;44:376-83.

Severe aortic stenosis with low transvalvular gradient and severe left ventricular dysfunction: result of aortic valve replacement in 52 patients. Circulation 2000;101: 1940–6.

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Tribouilloy C, Lévy F, Rusinaru D, et al. Outcome after aortic valve

contractile reserve on dobutamine stress echocardiography. J Am Coll Cardiol. 2009;53:1865-73. Roques F, Michel P, Goldstone AR, Nashef SA. The logistic EuroSCORE. Eur Heart J. 2003;24:882-3. Roques F, Nashef SA, Michel P, et al. Risk factors and outcome in European cardiac surgery: analysis of the EuroSCORE multinational database of 19030 patients. Eur J Cardiothorac Surg. 1999;15:816-22 http://209.220.160.181/STSWebRiskCalc261/ (accessed 30 Dec 2010). Osswald BR, Gegouskov V, Badowski-Zyla D, et al. Overestimation of aortic valve replacement risk by EuroSCORE: implications for percutaneous valve replacement. Eur Heart J. 2009;30:74-80. Engleman DT, Adams DH, Byrne JG, et al. Impact of body mass index and albumin on morbidity and mortality after cardiac surgery. J Thorac Cardiovasc Surg 1999;118:866-873 Chang A, Smedira N, Chang C, et al. Cardiac surgery after

J Thorac Cardiovasc Surg 2007;133:404-413. Ambler G, Omar RZ, Royston P, et al. model for heart valve surgery. Circulation. 2005;112:224-31. Al-Attar N, Nataf P. Development of aortic valve implantation. Herz. 2009;34:367-73. Himbert D, Descoutures F, Al-Attar N, et al. Results of transfemoral or transapical aortic valve implantation following a uniform assessment in high-risk patients with aortic stenosis. J Am Coll Cardiol. 2009;54:303-11. Al-Attar N, Ghodbane W, Himbert D, et al. Unexpected complications of transapical aortic valve implantation. Ann Thorac Surg. 2009;88:90-4. Al-Attar N, Himbert D, Descoutures F, et al. Transcatheter Aortic Valve Implantation: Selection Strategy is Crucial for Outcome. Ann Thorac Surg. 2009;88:90-4.

Transcatheter valve implantation for patients with aortic stenosis: a position statement from the European Association of Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J 2008; 29: 1463-70. Kamath AR, Varadarajan P, Turk R, et al. Survival in patients with severe aortic regurgitation and severe left ventricular dysfunction is improved by aortic valve replacement: results from a cohort of 166 patients with an ejection fraction < or =35%. Circulation. 2009;120:S134-8 Khandhar S, Varadarajan P, Turk R, et al. valve replacement in patients with severe aortic regurgitation and pulmonary hypertension. Ann Thorac Surg. 2009;88:752-6.

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