**7. Reoperation for isolated tricuspid regurgitation**

One critical question we aim to highlight in this article is: could ignoring the RV-free wall revascularization at the time of CABG have a late clinical impacts, such as RV dysfunction and functional TR in patients with extended RCA disease? Patients


### **Table 1.**

*Prevalence of coronary artery disease in patients undergoing transcatheter intervention for tricuspid regurgitation.*

### *Perspective Chapter: Right Ventricular Free Wall – The Forgotten Territory for Revascularization DOI: http://dx.doi.org/10.5772/intechopen.114819*

presenting for surgery for isolated tricuspid regurgitation, especially in the setting of reoperation after previous CABG, are often considered high-risk and likely will not be offered another surgery. This could be related to the high mortality rates reported among different groups [35]. These patients commonly present with clinical right heart failure manifestations secondary to RV dysfunction, including liver congestion, renal dysfunction, thrombocytopenia, and volume overload, which adds to the risk of the operation in addition to the technical aspects of re-operation after CABG with patent grafts. In that sense, there might be a group of patients developing right heart failure late after a CABG procedure who will not be referred to the surgeons by the cardiologists, knowing they are high-risk patients. In the current era of evolving trans-catheter therapies, a number of high-risk surgical patients could be referred to tricuspid valve catheter therapies [36]. History of coronary artery disease, PCI, and/or CABG with RV dysfunction can be observed in the reports of trans-catheter tricuspid valve intervention along with common etiologies of functional TR such as pulmonary hypertension, atrial fibrillation, and pacemaker leads (**Table 1**). In these reports, approximately one-third of patients had a history of CAD, PCI, and CABG, however no granular data was available about the extent of RCA disease or the status of revascularization. Additionally, trans-catheter intervention reports do not include all patients developed TR after CABG as some of these patients may not be candidates for available trans-catheter trials. Thus, it would be difficult to estimate how many patients present with significant TR after CABG as this is not a common long-term outcome to study, which is primarily focused on survival and graft patency [12, 15, 16, 46, 47].

## **8. Conclusions**

RV-free wall ischemic disease is not routinely addressed during the current CABG practice. The impact of ignoring the RV-free wall revascularization is not well examined in dedicated studies. In the early era of CABG evolution, there was more attention to RV-free wall ischemic disease; however, less attention continued toward RV revascularization. Due to the nature of the RV tolerance to ischemia and the presence of collateralization between the RCA and the left coronary system, the majority of patients with extended RCA disease may not have a prominent early impact of RV dysfunction if they underwent standard distal bypass. Perhaps this is the rationale for surgeons deviating away from RV-free wall revascularization in modern CABG practice, as they may not observe an early impact. However, the available data in the literature that we presented in this review suggests late RV dysfunction after CABG with worsening functional TR in some patients. This in part could be related to pulmonary hypertension or left-sided cardiac pathology, but it could also be very well related to ongoing RV-free wall ischemia that results in RV cardiomyopathy and functional TR, mimicking ischemic MR. At this point, further dedicated studies focusing on the long-term impact of ignoring RV-free wall ischemia are needed to develop a consensus, if proven significant. Addressing RV-free wall ischemic disease does not require additional complex procedures, but simply adding a bypass to an acute marginal branch or mid-RCA in patients with extended RCA disease (**Figure 1**). This may avoid the development of late RV dysfunction and functional TR in certain groups of patients with extended RCA disease without robust collateralization.

### **Figure 1.**

*A: Preoperative coronary angiogram showing significant in-stent stenosis lesion (arrow) of the proximal right coronary artery (RCA), significant lesion (arrow) in the proximal posterior descending artery (PDA), and a medium sized marginal artery branch (AMB) originating between the two lesions. B: Operative photo of bypass grafting to acute marginal branch (AMB, dashed line) using side-to-side sequential anastomosis technique (arrow) of the bypass graft to posterior descending artery (SVG to PDA). RA: Right atrium, RV: Right ventricle.*

*Perspective Chapter: Right Ventricular Free Wall – The Forgotten Territory for Revascularization DOI: http://dx.doi.org/10.5772/intechopen.114819*
