4 | DISCUSSION
To the best of our acknowledgement, the literature of TVS is based on retrospective studies with multiple criteria inclusion - ischemic heart disease with or without concomitant coronary surgeries [1-4,6-7,9-10], active infective endocarditis [8]– or contemplating a selected group of patients [5], which narrows down the true effect of TVS. With this research, we tried to focus only on the outcomes of isolated triple valve disease.
As mentioned above, reported operative mortality in modern era ranges between 5 and 17% [1-4,6-10]. Akay reported a very low operative mortality (2.5%), but it was from a young population with rheumatic valve disease and, consequently, lower surgical risk [5]. Our experience, including patients only with valvular disease, detected a similar mortality rate (12%). Of note, our series included almost 2/3 of patients in NYHA class III or IV, 1/4 with previous valve surgery, important pulmonary hypertension and with a substantial operative risk (mean EuroSCORE II 7.5%).
Age, NYHA class IV, depressed LVEF, prolonged CPB, arterial hypertension, previous cardiac surgery, peripheral vascular disease, preoperative shock, and preoperative renal disfunction were already identified as independent risk factors for perioperative mortality after TVS [2-3,7,9,10]. Our study underlines the important role of normal renal function in patients submitted to TVS, identifying it as a marker of increased perioperative survival. We also consider DM as a challenge on TVS in-hospital mortality.
Another fact that emphasizes TVS as a serious procedure is the high operative major complication rate, reported in the recent registries as 43-53% [1-2,5]. This study reports a lower complication rate (28.7%), possibly explained by the inclusion criteria in the different series. To our acknowledgement, there is no evidence of predictors of perioperative morbidity after TVS in literature [1-10]. However, our study identified the increase of sPAP and obesity as independent predictors of early morbidity. DM and normal renal function are also important clinical factors respecting post-operative complications. This study highlights the importance of the comorbidities not only for mortality issues, but also for early morbidity. This might have important implications as some of these risk factors are potentially modifiable before surgery. Whereas pulmonary hypertension depends on the correction of the underlying valve disease, obesity is clearly modifiable and a potential target for preoperative intervention strategies to improve outcomes.
Former reports had shown that TVS is associated with 5- and 10-year survival rates of 55-87% and 35-65%, respectively [1-4,6]. In the present research, late mortality rates were 66% at 5 years and 45% at 10 years, which fall within the range of previously reported results. Noack identified older age, NYHA class IV, preoperative liver failure, preoperative HD and depressed LVEF as risk factors of late mortality [4]. We identified DM as a risk factor for long-term mortality and the increase of creatinine clearance as predictor of long-term survival. Patients with gastrointestinal diseases seem to have also a higher risk of long-term mortality.
The rates of freedom from reoperation at 5-10 years have been reported from 84.3 to 97% [3,8-9]. At our institution, only 3,5% required late reoperation, which supports the late good results of this surgery.
This study has multiple limitations. It is based on the retrospective analysis of a population submitted to several combinations of procedures and operated by different surgeons. It is also limited by the small sample size of our study population, with low number of events, turning the statistical analysis into a difficult procedure with associated inherent uncertainty. The constrained access to other institutions’ records limited us to accurately identify morbidity during follow-up.