Review
An Approach to the Rational Use of Revascularization in Heart Failure Patients

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Abstract

The most common cause of heart failure with reduced ejection fraction (HFrEF) is coronary artery disease. A multitude of factors come into play when deciding whether a patient with HFrEF and coronary artery disease should have coronary artery bypass graft (CABG) surgery, percutaneous coronary intervention, or medical therapy alone. For candidates for percutaneous coronary intervention and CABG, evidence from large registries would suggest that patients with 2-vessel coronary artery diseases and proximal left anterior descending disease and all patients with 3-vessel coronary artery disease do better with CABG. For patients that are candidates for medical therapy with or without CABG, the results of the Surgical Treatment for Ischemic Heart Failure (STICH) trial indicate that with CABG, the reduction of mortality is not statistically significant (hazard ratio [HR], 0.86; P = 0.12). However, CABG is superior in reducing cardiovascular deaths (HR, 0.81; P = 0.05), and the combination of cardiovascular deaths and cardiovascular hospitalizations (HR, 0.74; P < 0.001). Patients undergoing CABG have an upfront risk that is eliminated by 2 years and thereafter do better. The assessment of cardiac viability or reversible ischemia does not appear to be helpful in determining which individuals will improve more with CABG. Patients with severe mitral regurgitation who undergo CABG appear to benefit from simultaneous valve repair but not from the addition of surgical ventricular reconstruction of the left ventricle, although in specific patients this might be considered. The totality of evidence would thus suggest that patients with HFrEF should be evaluated for the possibility of coronary revascularization if they are candidates for CABG.

Résumé

La coronaropathie est la cause la plus fréquente de l’insuffisance cardiaque à fraction d’éjection réduite (ICFER). De nombreux facteurs entrent en jeu lorsque vient le temps de décider si un patient ayant une ICFER et une coronaropathie devrait subir un pontage aortocoronarien (PAC), une intervention coronarienne percutanée ou un traitement médical seul. Pour ce qui est des candidats à l’intervention coronarienne percutanée et au PAC, les données scientifiques provenant d’importants registres ont montré que les patients ayant des coronaropathies bitronculaires et une sténose de l’artère interventriculaire antérieure proximale, et que tous les patients ayant une coronaropathie tritronculaire bénéficieraient plus d’un PAC. Pour ce qui est des patients qui sont des candidats au traitement médical associé ou non au PAC, les résultats de l’étude STICH (Surgical Treatment for Ischemic Heart Failure) indiquent qu’avec le PAC la réduction de la mortalité n’est pas statistiquement significative (rapport de risque [RR], 0,86; P = 0,12). Cependant, le PAC est supérieur en ce qui a trait à la réduction des décès liés à la maladie cardiovasculaire (RR, 0,81; P = 0,05), et à la combinaison des décès et des hospitalisations liés à la maladie cardiovasculaire (HR, 0,74; P < 0,001). Les patients subissant un PAC ont un risque à court terme qui est éliminé au cours des 2 années subséquentes et s’améliorent par la suite. L’évaluation de la viabilité cardiaque ou de l’ischémie réversible n’apparaît pas utile pour déterminer les individus qui s’amélioreront le plus après un PAC. Les patients ayant une régurgitation mitrale grave qui subissent un PAC semblent bénéficier de la réparation valvulaire simultanée, mais non de la reconstruction chirurgicale du ventricule gauche, bien que cela puisse être envisagé chez certains patients. L’ensemble des données scientifiques montrerait donc que les patients ayant une ICFER devraient être évalués quant à la possibilité de revascularisation coronarienne s’ils sont candidats au PAC.

Section snippets

CABG in Patients With LV Systolic Dysfunction

Hypothesis 1 of the STICH trial, which compared modern medical management with and without CABG in patients with a LVEF ≤ 35% and CAD amenable to CABG, served to update our approach to revascularization of patients with HFrEF. In STICH, patients were eligible for medical therapy alone if they did not have stenosis of 50% or more of the diameter of the left main coronary artery and if they did not have Canadian Cardiovascular Society class III or IV angina while receiving medical therapy. The

Subgroup Analyses of STICH Patients

Patients enrolled into the STICH trial all had CAD amenable to CABG, so any subgroup analyses of the STICH population presupposes that patients could have either CABG or medical therapy. Thus, many patients with CAD and HFrEF were excluded from STICH. These include those in whom CABG is clearly indicated, such as patients with significant left main-stem coronary obstruction or with severe anginal symptoms, and patients in whom CABG is clearly contraindicated because of the very high risk of

Role of Assessing Myocardial Viability and Ischemia

Numerous studies over the past few decades have indicated that HFrEF in patients with CAD is not always an irreversible process, because LV function might improve substantially after CABG. Imaging protocols with echocardiography, nuclear imaging, and cardiac magnetic resonance designed to detect viable myocardium are useful in predicting the likelihood of recovery of LV function with revascularization, and these imaging protocols are often used to select patients with HFrEF for CABG. Numerous

Role of CABG vs PCI

No clinical trial comparing revascularization with CABG or PCI of patients with HFrEF exists. All available data comparing the revascularization of such patients comes from large observational studies.26 Accepting this limitation, all observational studies suggest superiority of CABG over PCI in most patient subgroups with HFrEF. The largest of these databases is the New York database for coronary revascularization. In that database, patients with a LVEF < 40% and 2-vessel CAD, but without

Role of SVR With CABG

In hypothesis 2 of the STICH trial, patients who had a clear indication for CABG, a LVEF ≤ 35%, and anterior akinesis/dyskinesis thought to be amenable to SVR were randomized to CABG with or without SVR.28 The addition of SVR was found to have no effect on survival or subsequent hospitalization for cardiovascular disease (Fig. 5). Prespecified subgroup analyses demonstrated no significant interaction with SVR suggesting, that as a whole, SVR surgery was not beneficial for STICH patients. This

Role of Mitral Valve Repair With CABG

It is well known that patients with moderate to severe mitral regurgitation (MR) and HFrEF have a worse prognosis than those with mild or no MR. The STICH trial confirmed the detrimental role of MR in patients with HFrEF and demonstrated improved survival when moderate to severe MR was repaired.30 The results of STICH notwithstanding, at this time no large definitive prospective randomized controlled study supporting improved survival with mitral valve surgery performed alone or at the time of

Funding Sources

Supported by the National Heart, Lung and Blood Institute (NHLBI).

Disclosures

The authors have no conflicts of interest to disclose.

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