Preprocedural characteristics
The optimal approach for managing aortic valve disease is still a hot topic, with continuous updates on recommendations and guidelines [14, 15]. In this study, we presented our experience in TAVR and compared hospital and long-term outcomes between SAVR and TAVR. The baseline characteristics of TAVR patients varied widely from those who had SAVR. TAVR patients were significantly older than SAVR patients. This finding is expected since the value of TAVR in young patients has not been established yet [8]. The age of our TAVR patients is comparable to those in PARTNER trials [2, 4, 6]. This fundamental difference in age is attributed to SAVR being the standard of care in young patients. Those patients will benefit from having mechanical valves to decrease the odds of aortic valve reoperations [16]. Consequently, TAVR patients had higher EuroSCORE II and more prevalence of comorbidities. Patients were recruited until 2019, and the evidence to use TAVR in low-risk patients was introduced recently [7], and high-risk surgical patients are assigned to TAVR.
Gender distribution significantly differed between TAVR and SAVR, and female patients were significantly higher in the TAVR group. Calcific aortic stenosis has no sex predilection; however, rheumatic and degenerative aortic valve diseases are more common in females [17]. The high prevalence of females who underwent TAVR in our series could be attributed to the surgical risk in females. Surgery in women is more demanding, and the incidence of stroke and operative mortality after SAVR was higher in women compared to men [18,19,20]. Additionally, the PARTNER trial showed that women randomized to TAVR had better survival compared to those randomized to SAVR [2].
Patients with aortic regurgitation were more in the SAVR group. This finding is because most TAVR studies were performed on aortic stenosis, and the aortic dilatation in patients with regurgitation may not be suitable for TAVR. Alharbi and associates evaluated the results of TAVR in patients with pure aortic regurgitation, and there was no difference in hospital mortality between TAVR and SAVR [11].
Procedural outcomes
In our series, postoperative pacemaker insertion was higher in TAVR patients. This difference was significant in the unmatched cohort and non-significant after matching. Heart block after TAVR is one of the most encountered complications [21]. Several mechanisms could contribute to this, including the proximity to the conduction system and the nature of the expanding valves [22]. There was no difference in the postoperative PPM between groups after matching, which could be related to using sutureless valves in the SAVR group. On the other hand, new-onset atrial fibrillation was significantly higher in the SAVR group, which is similar to other series [23]. Therefore, TAVR could be recommended in high-risk patients for atrial fibrillation. The paravalvular leak was extensively studied after TAVR, and its incidence ranged from 7 to 40% due to various definitions and grading used in different studies [24]. Paravalvular leak reported in our series was 11% in a 5-year follow-up.
Hospital mortality did not differ significantly between TAVR and SAVR; however, long-term survival was better in SAVR patients. In a meta-analysis by Swift and colleagues, the risk of all-cause mortality was increased after TAVR but did not reach a significant level [1]. Meanwhile, Siontis and colleagues reported a reduced risk of death with TAVR, and the survival benefit was evident in patients who had transfemoral TAVR [25]. However, this difference was not evident over longer follow-up periods.
We reported no significant difference between groups in the composite endpoint of stroke, aortic valve reintervention, and heart failure rehospitalization. Swift and colleagues reported a decreased risk of stroke with TAVR but did not reach a significant level [1]. PARTNER 3 trial reported a reduced cardiac rehospitalization rate after TAVR [26]. Few studies evaluated aortic valve reintervention after TAVR; however, the durability of TAVR valves was comparable to SAVR valves after 5 and 6 years [27, 28].
Additionally, we evaluated the long-term echocardiographic follow-up in our series, specifically the change in EF and peak aortic valve pressure gradient. TAVR and SAVR were associated with improvement in ejection fraction, while the pattern was different. TAVR was associated with an immediate improvement in the EF, while the effect of SAVR on ejection fraction was evident after six months. The peak gradient was significantly lower in TAVR, which could be attributed to the larger valves used in TAVR. The delayed change in EF in the SAVR group could be attributed to cardiopulmonary bypass and myocardial protection.
The debate about the optimal approach for aortic valve surgery will continue. Several gaps need to be addressed, and the evolving technology makes the comparison uneven. The comparison did not consider some technical issues, including the miniaturized cardiopulmonary bypass [29], aortic valve repair [29, 30], the minimally invasive approach, and robotic SAVR [31,32,33]. In a meta-analysis, minimally invasive SAVR was associated with lower mid-term mortality compared to TAVR [34]. The future inclusion of these factors in the comparison could be a game changer.
Study limitations
The study has several major limitations. First, the design is retrospective with its inherent selection bias. The propensity score matched the measured data; however, several patients’ characteristics and comorbidities could affect the treatment outcomes but were not included in the analysis. Second, the study is a single-center experience, and the generalization of the results may not be applicable. Third, there was great variability in the baseline characteristics of the included patients, which affected the number of matched patients and the results. Fourth, the timeline for TAVR and SAVR is different, which may have introduced selection bias. Fifthly, the number of patients with SAVR is low because we included isolated aortic valve procedures only. In the era of TAVR, patients with single valves and a high risk of surgery were assigned to the TAVR group. Additionally, rheumatic fever is the most common cause of valve lesions in our region, and it rarely affects the aortic valve without mitral affection. Lastly, the number of events is low, and this could be a reason for not detecting the statistical significance of some outcomes.