In this issue of the Indian Journal of Thoracic and Cardiovascular Surgery, Honda et al. report their institutional experience with concomitant transcatheter aortic valve implantation (TAVI) and both off-pump coronary artery bypass grafting (OPCAB) and minimally invasive coronary artery bypass grafting (MICS-CABG) [1]. After analyzing 20 cases of TAVI with OPCAB and 7 cases of TAVI with MICS-CABG, the authors report overall safety of the procedure in their series with no 30-day or in-hospital mortality and 100% graft patency at 6 months in all patients (23 out of 27) who underwent scheduled coronary computed tomography or magnetic resonance imaging. However, incomplete revascularization occurred in one in three patients.

This study adds to the limited but growing body of observational evidence that concomitant TAVI and OPCAB or MICS-CABG is feasible [2, 3]. Slowly but surely, the question of performing TAVI + OPCAB or TAVI + MICS-CABG is moving from “can we?” to “should we?”. Thus far, the evidence suggests that we “should,” but only in institutions with off-pump and minimally invasive expertise and in very carefully selected patients.

In most institutions, the debate centers around whether patients undergoing TAVI who have coronary artery disease (CAD) require coronary intervention at all. Transcatheter aortic valve implantation with percutaneous coronary intervention (TAVI + PCI) is a class IIa indication for patients with proximal or left main disease in the 2020 ACC/AHA Valvular Heart Disease guidelines; however, current evidence has shown that not all patients undergoing TAVI with CAD require coronary intervention and there is some evidence of higher bleeding risk post-TAVI when PCI is performed prior, due to dual antiplatelet therapy use [4]. The ACTIVATION trial compared TAVI with or without PCI in patients with primarily single-vessel disease and demonstrated no significant difference in death, re-hospitalization, or major adverse cardiovascular events at 1 year, but an increased risk of bleeding in the PCI group at 30 days post-TAVI [5]. In an observational analysis of patients undergoing TAVI with PCI as indicated, patients with an initial SYNTAX score < 22 or residual SYNTAX score < 8 had similar long-term mortality compared with patients without CAD [6]. A study investigating the natural history of untreated coronary disease after TAVI showed that only 3.4% of patients with single vessel disease and 7.4% of patients with multivessel disease required unplanned PCI at 10 years follow-up [7].

Although evidence increasingly points to the safety of conservative therapy in mild concomitant coronary disease, decision-making differs as disease severity increases. In low- to moderate-risk patients who have severe multivessel CAD with a SYNTAX score ≥ 33, guidelines recommend surgical aortic valve replacement and coronary artery bypass grafting (SAVR + CABG) in preference to TAVI + PCI. However, equipoise remains, particularly when the coronary disease is less severe and is amenable to both PCI and CABG. The TCW trial (NCT03424941) is comparing SAVR + CABG with TAVI + PCI in patients ≥ 70 with two or more lesions or single lesion involving the left anterior descending artery, seeking to answer this question. Until then, SAVR + CABG should remain standard of care in patients without contraindications for surgery [8].

With increasing age, frailty, and co-morbidities, the risk–benefit ratio shifts back towards conservative management. In these patients, when coronary disease is severe, TAVI + PCI may be the preferred option, although comparative data are very limited. When PCI is not amenable or suitable, concomitant MICS-CABG or OPCAB are reasonable alternatives to consider in the setting of a Heart Team discussion. Patient factors that would portend to TAVI + OPCAB would include patients with severe CAD and a SYNTAX score > 33, porcelain aorta, and/or chronic kidney disease. TAVI + MICS-CABG may be preferred in patients with left-sided CAD alone, previous sternotomy, and increased anteroposterior chest diameter. Regardless, institutional expertise and comfort with OPCAB and MICS-CABG along with careful patient selection is crucial to the safety and effectiveness of these procedures, as prior studies on TAVI + OPCAB have reported 30-day mortality rates up to 14.3% [9]. Although the short-term outcomes in this study were encouraging, as the authors mention, there was a learning curve and their operative times were over 100 min longer in their early experience compared to their late experience. For concomitant CAD when PCI is not preferred, the decision to choose SAVR + CABG compared to TAVI + OPCAB may ultimately depend on institutional specific practices and outcomes. In Japan, where OPCAB is much more commonly performed, a TAVI + OPCAB approach to repairing severe aortic stenosis and CAD may indeed be the safer option in the hands of experienced off-pump surgeons.

The topic of incomplete revascularization also warrants discussion. In Honda et al., one in three patients were incompletely revascularized, which is associated with increased mortality after TAVI [1]. It is thought that the primary mechanism of benefit for CABG compared to PCI is through protecting myocardium from proximal plaque rupture and myocardial infarction, which provides a potential mechanistic explanation for the importance of achieving complete revascularization [10]. In this regard, the decision on revascularization strategy should not sacrifice long-term gains for short-term wins, and reducing the number of unprotected lesions should be considered an important therapeutic goal, although treatment decisions should be individualized to the patient’s life-expectancy and clinical status.

In their work, Honda et al., by focusing on a cohort of higher risk, elderly patients with severe concomitant CAD not amenable to PCI have shown that in an institution with expertise and through careful patient selection, TAVI + OPCAB and TAVI + MICSCABG can be performed with favorable short-term outcomes and graft patency [1]. These procedures provide the Heart Team with another tool in the armamentarium for the treatment of concomitant severe aortic stenosis and CAD. Determining the generalizability and effectiveness of these procedures will require longer term follow-up and greater patient volume, preferably through a propensity score–matched multicenter cohort study or ideally a randomized controlled trial. Until we have further evidence to guide our practices, these procedures should be performed only in carefully selected patients located in centers with adequate expertise.