Treatment of aortic stenosis associated with coronary arteriosclerosis

It is widely accepted that the treatment for symptomatic aortic stenosis is aortic valve replacement (AVR). Balloon dilatation provides only a limited and transient improvement and does not influence the natural history of the disease. However, concern remains as regards the optimal treatment of aortic stenosis and associated coronary artery disease according to the respective severity of both pathologies.

Symptomatic aortic stenosis associated with significant coronary artery disease Although the benefits are not irrevocably proven, it is generally accepted that patients with significant aortic stenosis associated with significant coronary artery disease (stenosis > 50% or 70% of vessel diameter) should be treated by combined AVR and coronary artery bypass grafting (CABG).1 Many series have reported immediate and late results of combined valvar and coronary surgery in patients with aortic and coronary disease and compared these results with those obtained after isolated AVR in patients with aortic stenosis without coronary lesions. It is difficult to summarise the results of all these series, because they are het-erogenous in regard to the type of aortic valve disease (aortic stenosis or mixed aortic stenosis and regurgitation), the severity of coronary disease, and the period of operation (table 19.1).7-12 Patients treated in the 1980s and '90s were older and had more frequent coronary diseases.2 This evolution may explain the persistence of a relatively high operative mortality of combined AVR and CABG, between 5-10% in most series. The improvement of perioperative management is probably partly counterbalanced by the increasing proportion of elderly patients with comorbidities.

Comparative studies most often reported higher perioperative mortality rates after com bined surgery than after AVR alone. The relevance of such comparisons is, however, limited by the fact that patients with or without coronary artery disease differ by many characteristics. In particular, patients with coronary artery disease are generally older, more symptomatic, and more frequently have left ventricular dysfunction. We attempted to diminish the effect of these confounding factors in a study comparing patients undergoing combined aortic and coronary surgery with patients having normal coronary arteries and undergoing isolated AVR, who were matched for age, sex, functional class, left ventricular ejection fraction, and the date of operation.11 Despite matching in some important predictive factors, there remained a trend towards a higher operative mortality (10.4% v 4.9%, p = 0.08) in patients undergoing combined aortic and coronary surgery. In multivariate analysis taking into account other patient characteristics, combined CABG is associated with a lower increase in operative mortality than in univariate analysis.2 These findings do not indicate that CABG in itself increases the risk of AVR, but should be interpreted as the adverse influence of an associated atherosclerotic disease on the result of cardiac surgery.

Long term results after AVR associated with CABG are generally good, with survival rates > 60% at nine and 10 years in recent studies, despite the high risk profile of the patients (table 19.1).10 11 The comparison of late results after isolated AVR in patients with normal coronary arteries reveals the same limitations as the comparison of early mortality, because of the differences in the patients involved. In matched populations, mortality was not significantly higher in patients undergoing combined surgery up to nine years after the postoperative period.11 Relative survival, compared with a standard population, was not influenced by CABG until 10 years after surgery in another series.2 Apart from survival, late functional results are excellent in most series, most patients being in New York Heart Association (NYHA) class I—II, without a low incidence of angina and acute coronary events.9-11

Despite a trend towards an increase in perioperative mortality compared with patients with normal coronary arteries, the immediate results of AVR associated with CABG are satisfying according to the characteristics of the patients involved. These results support the current practice which is to bypass significant coronary artery stenosis (50% for left main and 50-70% for other arteries) when possible in

Figure 19.1. Calcified aortic stenosis associated with a 50% distal left main stem stenosis.
Figure 19.2. Calcified aortic stenosis with a tight stenosis on the second segment of a diffusely atherosclerotic right coronary artery.

patients who should have AVR for aortic valve stenosis (figs 19.1 and 19.2).1 The extrapolation of large series on CABG suggests that the use of the left internal mammary artery should be recommended for the grafting of the left anterior descending artery in those patients more frequently operated on at an advanced age, and for whom late reoperation should be avoided.

Isolated AVR inpatients with coronary artery stenosis

Published series comprise only a few patients who had coronary stenosis associated with aortic stenosis and who underwent isolated AVR without CABG. Moreover, these patients constitute a particularly heterogeneous group, because the absence of CABG can be related to very different situations, whether it is deliberate in moderate stenosis (approximately 50%) or impossible in significant stenosis because of anatomical conditions. The absence of CABG was deliberate in all cases only in the Bonow series,13 which reported a favourable outcome

Table 19.1 Results of aortic valve replacement combined with coronary artery bypass grafting in patients with aortic valve disease associated with coronary artery disease

Years of


Mean age

3 vess*

el or LM Operative




AS (n)



deaths (%)

Late survival (%)








49 at 10 years














52 at 10 years*








41 at 10 years








62 at 10 years








67 at 9 years









*Among postoperative survivors.

AVR, aortic valve replacement; AS, aortic stenosis; CABG, coronary artery bypass grafting, LM, left main stenosis.

*Among postoperative survivors.

AVR, aortic valve replacement; AS, aortic stenosis; CABG, coronary artery bypass grafting, LM, left main stenosis.

Figure 19.3. Calcified aortic stenosis with atherosclerosis of left anterior descending and circumflex arteries, no stenosis being more than 50%.

but whose interpretation should take into account the majority of mono-vessel diseases and the short follow up. In our experience, mid term outcome after isolated AVR in patients who had aortic stenosis associated with moderate coronary artery stenosis (40-60%) is excellent and identical to patients with normal coronary arteries (fig 19.3).11 As regards patients who had aortic stenosis and significant coronary disease which could not be bypassed for technical reasons, there was a trend towards a higher postoperative mortality and a more rapid decrease of the survival curve after a four year follow up.7 10 11 However, mid term survival was satisfying (60% at five years) and functional results were good, with more than 90% of the patients being free from angina in the absence of CABG.11 It is necessary to be cautious given the small number of patients, but these results strongly suggest that AVR should be performed in patients with symptomatic aortic stenosis, even if they have significant coronary lesions which cannot be bypassed for technical reasons. Immediate and late results seem less satisfying than those in patients who underwent combined aortic and coronary surgery but are far better than the natural history of aortic stenosis. Future studies are needed to evaluate the association of transmyocardial laser revascularisation with AVR in such patients.

Moderate aortic stenosis associated with significant coronary artery disease In patients who have moderate aortic stenosis and significant coronary artery disease for which there is an indication for revascularisation, percutaneous coronary angioplasty should be considered if possible. In patients who have coronary artery disease requiring CABG, the therapeutic choice is between :

• associating AVR and CABG, which is a radical treatment but exposes the patient to a higher operative risk and, later, to prosthetic related complications;

• performing only CABG, which will expose the patient to a subsequent AVR in case of progression of the aortic stenosis.

The mean rate of progression of aortic stenosis has been estimated at between 5-8 mm Hg per year for mean gradient, with a mean decline between 0.1-0.2 cm2 per year in valve area.14 However, it is very difficult to predict the progression of aortic stenosis in any given patient. Valve replacement in a patient who has previously undergone CABG can be technically complex and associated with an increased mortality.15 The possible evolution of moderate aortic stenosis and the risk of subsequent surgery leads to AVR, associated with CABG, being recommended in patients who have moderate aortic stenosis associated with coronary lesions requiring surgery. Valve replacement should be performed if valve area is below 1 cm2 and considered if between 1-1.5 cm2, and/or if mean aortic gradient is between 30-50 mm Hg.1

Choice of prosthesis

The major determinant of the choice between a mechanical prosthesis and a bioprosthesis is the comparison between the presumed life expectancy of the patient and the duration of the prosthesis. Bioprostheses are clearly recommended for patients over 80 years old, while mechanical prostheses are generally preferred in patients aged <70 years. The choice may be difficult between 70 and 80 years. Coronary disease is frequently associated in this age group and can be considered as a promoting factor for a mechanical prosthesis, though this point is controversial.16 Patients undergoing combined aortic and coronary surgery may have a life expectancy that will expose them to primary degeneration of the bioprosthesis. The risk of reoperation, which is still high in the elderly, is even more increased in patients who have previously undergone combined aortic and coronary surgery.

Medical treatment after combined aortic and coronary surgery

Patients who have undergone AVR with a mechanical prosthesis can benefit from moderate anticoagulation (target international normalised ratio 2-3), provided their thrombo-embolic risk is low—that is, patients in sinus rhythm, without previous embolism and with no severe enlargement of the left atrium.17 Moderate anticoagulation ensures an efficient protection against embolic events at a lower haemorrhagic risk. This point is particularly important after combined aortic and coronary surgery because patients should also be treated with aspirin. The combination of anticoagulants and aspirin is not recommended in all patients with prosthetic heart valves, but its use is supported by the results of clinical trials in patients who have mechanical heart valves associated with atherosclerotic disease.

Patients with CABG particularly benefit from treatment with statins. It is logical to consider prescribing a statin in most, if not all, patients who have undergone combined aortic and coronary surgery. The choice ofthe type of statin must take into account the possibility of drug interaction with oral anticoagulant treatment.

Combined aortic valve replacement and coronary artery bypass grafting (CABG)

• CABG should be conducted in association with aortic valve replacement, when possible, for all coronary arteries with significant stenosis.

• In patients who have significant, non-bypassable coronary artery stenosis, aortic valve replacement, if otherwise indicated, should not be contraindicated on the basis of coronary status.

• The progression of aortic stenosis and the problems related to valve replacement after previous coronary surgery support wide indications for aortic valve replacement in patients who have moderate aortic stenosis and in whom CABG is indicated.

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