After the removal of duplicates, a total of 319 manuscripts were identified; full-text eligibility was assessed for 35 of them and, finally, 9 articles could be included (Fig. 2 and Table 1)[12–16, 22, 35–37]. Figure 3 summarizes the quality assessment of selected reports using AXIS tool. Quality resulted in being high in 4 (44%) of studies and medium in 5 (56%). Quality assessment of each manuscript is provided in Supplemental Fig. 1.
Table 1
Selected studies (n = 9) and demographic characteristics of patients.
Author | Year | Cohort Period | Cases | | Controls | Age at TV repair (years) | Male | Follow-up (years) | Timing of TV repair (n) |
(n) | | (n) | median (IQR) / mean (SD) | (n) | median (IQR) / mean (SD) | At Norwood | Interstage I | At Glenn | Interstage II | At Fontan | After Fontan |
Hoda | 2022 | 2007–2021 | 16 | | - | 0.3 (0.02-3) [range] | 11 | 0.4 (0–3) [range] | 2 | 3 | 5 | 1 | 5 | 0 |
Wamala | 2022 | 2006–2017 | 18 | | 35 | 0.02 (0.01–0.03) | 11 | - | 18 | 0 | 0 | 0 | 0 | 0 |
Ono | 2020 | 1999–2018 | 44 | | 205 | 0.4 (0.3–1.6) | - | 4.8 (2.3–6.7) | 0 | 4 | 23 | 3 | 14 | 0 |
Alsoufi | 2018 | 2002–2012 | 30 | | - | 0.5 (0.01–4.1) | 16 | 7.8 (3.8) | 4 | 0 | 17 | 0 | 8 | 1 |
Huang | 2016 | 2004–2013 | 11 | | 37 | 0.02 (0.01–0.03) | - | - | 11 | 0 | 0 | 0 | 0 | 0 |
Bautista-Hernandez | 2014 | 2000–2012 | 35 | | - | 1.9 (0.5–16.2) | - | 3.3 (0.1–14.8) | 0 | 0 | 15 | 4 | 27 | 7 |
Ruzmetov | 2014 | 1988–2012 | 11 | | 46 | 0.8 (0.5–2.3) | 4 | 7.9 (6.5) | 1 | 0 | 4 | 3 | 2 | 1 |
Sugiura | 2014 | 1991–2010 | 26 | | - | 0.7 (0.8) | - | 4.9 (4.4) | 9 | 0 | 13 | 3 | 3 | 0 |
Nakata | 2010 | 1999–2008 | 12 | | - | - | - | 3.1 (3.1) | 5 | 2 | 2 | 1 | 2 | 0 |
IQR: interquartile range; SD: standard deviation; TV: tricuspid valve. |
Patient characteristics
We identified a total of 203 patients who underwent surgical repair of TVR across series. Median/mean age at TV repair ranged from 0.02 to 1.9 years (Table 1). The majority of operations occurred concomitantly to the scheduled palliation procedures: 50 (24.6%) at the time of Norwood operation, 9 (4.4%) during interstage I period, 79 (38.9%) at bidirectional cavo-pulmonary connection (bidirectional Glenn) surgery, 15 (7.4%) during interstage II period, 61 (30%) at Fontan operation, and 9 (4.4%) after Fontan completion (Supplemental Fig. 2). Median/mean follow-up ranged from 0.4 to 7.9 years.
Surgical strategy
The most common surgical technique for TV repair was commissuroplasty (139/191 patients, 72.8%), followed by annuloplasty (113/191, 59.2%), neo chordae implantation (24/191, 12.6%), leaflet adaptation (20/191, 10.5%), cleft closure (16/191, 8.4%), edge-to-edge stitch (12/191, 6.3%), and other less frequent procedures (13/191, 6.8%). The study of Nakata and colleagues[37] did not report a detailed description of TV repair techniques for HLHS patients, thus was excluded from this sub-analysis. Table 2 and Supplemental Fig. 3 summarize the adopted surgical techniques in each selected manuscript.
Table 2
Surgical techniques for TV repair adopted in the selected studies (n = 8).
Author | Year | TV repair techniques (can be multiple in the same patient) |
Annuloplasty | Commissuroplasty | Neo Chordae | Edge-to-Edge | Cleft Closure | Leaflet Adaptation | Other |
Hoda | 2022 | 8 | 9 | 0 | 3 | 0 | 0 | 1 |
Wamala | 2022 | 8 | 12 | 8 | 0 | 0 | 0 | 0 |
Ono | 2020 | 11 | 47 | 10 | 7 | 10 | 20 | 9 |
Alsoufi | 2018 | 25 | 12 | 0 | 0 | 2 | 0 | 3 |
Huang | 2016 | 8 | 3 | 0 | 0 | 1 | 0 | 0 |
Bautista-Hernandez | 2014 | 20 | 45 | 6 | 0 | 2 | 0 | 0 |
Ruzmetov | 2014 | 11 | 2 | 0 | 0 | 1 | 0 | 0 |
Sugiura | 2014 | 22 | 9 | 0 | 2 | 0 | 0 | 0 |
TV: tricuspid valve |
Early outcomes and transplant-free survival
From pooled analysis of the included studies, in-hospital mortality after TV repair was 9% [95% CI = 1–21%; I2 = 76.9%, p < 0.001, Fig. 4). The rate of patients undergoing TV repair at the time of Norwood operation acted as a modifier effect on the meta-analysis (estimate 0.004 [95% CI:0.0005–0.007] per 1% increase of Norwood rate, p = 0.024). Age at surgery (estimate − 0.16 [95% CI:-0.33-0.01], p = 0.066), follow-up period (estimate − 0.011 [95% CI:-0.097-0.076], p = 0.810), and cohort period (estimate − 0.024 [95% CI:-0.065-0.017], p = 0.253) did not present a modifier effect on the analysis.
The pooled risk of early (in-hospital) TV reoperation resulted to be 1% [95% CI = 0–5%; I2 = 32.9%, p = 0.15, Fig. 4). None of the considered variables had a modifier effect on the meta-analysis.
Five manuscripts[13, 15, 16, 22, 35] (for a total of 104 patients) reported Kaplan-Meyer curves with a follow-up starting from the time of Norwood operation, which allowed for the reconstruction of transplant-free survival data. The meta-analysis conducted on the identified studies estimated a transplant-free survival at 1, 2, 5, and 10 years of follow-up of 75.5% [95% CI = 67.6–84.3%], 69.4% [95% CI = 60.9–79%], 63.6% [95% CI = 54.6–73.9%], and 61.9% [95% CI = 52.7–72.6%], respectively (Fig. 5). Age at surgery (HR: 0.66, 95% CI = 0.20–2.19, p = 0.497), the rate of patients undergoing TV repair at the time of Norwood operation (HR: 1.00, 95% CI = 0.99–1.01, p = 0.631), follow-up time (HR: 0.93, 95% CI = 0.77–1.14, p = 0.491), and publication year (HR: 0.95, 95% CI = 0.84–1.08, p = 0.437) did not act as effect modifiers on the meta-analysis.
Pooled transplant-free survival of patients undergoing TV repair did not differ from the one of 323 patients with HLHS without TVR used as controls [13, 15, 16, 35] (p = 0.59, Fig. 5). When selecting those patients with TVR requiring surgery (n = 84) only from studies reporting controls[13, 15, 16, 35], transplant-free survival between the two groups was still comparable (p = 0.88, Supplemental Fig. 4), with a pooled HR of mortality of 1.12 (95% CI = 0.77–1.62, p = 0.568).
Freedom from TVR recurrence and freedom from reoperation
Four studies[13, 22, 36, 37] (including a total of 91 patients) reported estimates of freedom from recurrence of clinically significant TVR after TV repair. Pooled analysis revealed freedom from TVR recurrence at 1, 2, 5, and 10 years of follow-up of 65.9% [95% CI = 56.7–76.7%], 63.2% [95% CI = 53.8–74.3%], 57% [95% CI = 46.7–69.7%], and 48.7% [95% CI = 37.3–63.7%], respectively (Fig. 6). Age at surgery had a modifier effect on the freedom from regurgitation (HR: 0.32, 95% CI = 0.19–0.54, p < 0.001), with younger patients experiencing an increased risk of recurrence of TVR. Parallelly, the rate of patients undergoing TV repair at the time of Norwood operation acted as an effect modifier (HR: 1.02, 95% CI = 1.00-1.03, p = 0.021), increasing the risk of TVR recurrence. Follow-up time (HR: 1.27, 95% CI = 0.33–4.96, p = 0.730) and publication year (HR: 1.04, 95% CI = 0.85–1.27, p = 0.708) had not a modifier effect on the meta-analysis.
Five studies[13–16, 37] (for a total of 115 patients) estimated the freedom from TV reoperation after TV repair. Pooled analysis showed freedom from TV reoperation at 1, 2, 5, and 10 years of follow-up of 77% [95% CI = 69.4–85.4%], 71.4% [95% CI = 63.1–80.7%], 63.6% [95% CI = 54.5–74.3%], and 63.6% [95%CI = 54.5–74.3%], respectively (Fig. 6). Age at surgery acted as an effect modifier (HR: 0.05, 95% CI = 0.01–0.25, p < 0.001) and younger patients displayed an increased risk of TV reoperation. The rate of patients requiring TV repair at the time of Norwood operation had a modifier effect on the freedom from TV reoperation (HR: 1.02, 95% CI = 1.01–1.02, p < 0.001). Neither follow-up time (HR: 0.85, 95% CI = 0.67–1.07, p = 0.173) nor publication year (HR: 1.08, 95% CI = 0.92–1.26, p = 0.351) acted as effect modifiers on the meta-analysis.
Publication bias
The funnel plots, in addition to the traditional bands to identify publication bias, contain three shaded regions; these regions identified statistically significant effects for a significance level between 0.1 and 0.05, 0.05 and 0.01, and < 0.01. Concerning the in-hospital mortality outcome only two studies fail outside the funnel plot bounds indicating a controlled publication bias; the only reporting a significant effect despite the high standard error is Nakata et al[37].
The studies reporting the early (in-hospital) TV reoperation rate outcome fall all inside the funnel plot bounds indicating a substantial absence of publication bias.