Discussion
Minimally invasive cardiac surgery has been reported since the
1990’s14. Described benefits includes: reduced blood
loss and pain, shorter LoS, and generally, superior patient
satisfaction20. MI was also found beneficial in
high-risk patients to reduce surgical trauma7.
Due to the rarity of intra cardiac masses few studies comparing the
outcomes of MI and MS surgery have been published. The present
meta-analysis, by aggregating data from 11 studies, confirms that the MI
approach for cardiac tumor resection is as safe as MS, with excellent
early and late outcomes, very low recurrence rates, and rare need for
reoperation at follow-up.
Among the total number of 653 tumors described, 601 (92%) were myxomas,
22 (3.3%) papillary fibroelastoma, 13 (1.9%) thrombus, 6 (0.9%)
vascular malformation, 2 (0.3%) lipoma, 1 (0.1%) fibroma, 1 (0.1%)
rhabdomyoma, 1 (0.1%) chondrosarcoma, 1 (0.1%) hamartoma, and 5
(0.7%) classified as ‘other’. Only Ravikumar9included a case of secondary atrial chondrosarcoma.
This study confirms that the MI approach requires prolonged operative
time due to longer CPB and CC time. However, there was no demonstrable
effect on clinical outcomes and MI had similar rates of post-operative
complications as the MS approach. In line with previous studies, LOS was
significantly shorter in the MI group20. The same
results were observed in the subgroup analysis of the high-quality
studies10-14, 16.
Notably, we did not find significant differences in terms of tumor size
between groups. We may speculate that large masses may preclude the MI
approach. Nevertheless, even in cases of large size of the tumor, the MI
approach may be still feasible21.
Regarding the incidence of recurrences, our results are in line with
previously published literature. A retrospective study from the Mayo
Clinic spanning over 50 years reported a recurrence rate of 5.6% with a
MS approach22. Similarly, Keeling et al reported a
rate of 2%23 and in a prospective single cohort
series of patients treated with a minimally invasive approach, Bianchi
et al24 reported an incidence of recurrence of 3.3%.
With cardiac myxoma, while a stalk base resection is generally indicated
to avoid tumor recurrence, its superiority over endocardial resection is
under debate. The Mayo Clinic22 study demonstrated
that there were no differences in tumor recurrence based in resection
margin. Nevertheless, we could not analyze the impact of different
surgical techniques (e.g. resection with patch, endocardial resection,
single vs double atrial approach) on late recurrences.
In our meta-analysis, there were no conversions to sternotomy and the
rate of reopening for bleeding was similar between the two groups
(safety end-point). The presence of a right atrial tumor has been
reported as possible contraindication for a minimally invasive approach
due to fragmentation during cannulation procedures25.
Importantly, there was no difference in the occurrence of post-operative
neurological events and no clinically relevant embolization events were
observed in the MI group.
All series included in the analysis were low-medium volume, likely due
to the rarity of cardiac tumors. With this in mind, we could not
evaluate the effect of the surgical cumulative volume on clinical
outcomes4.
While a majority of patients included in this study had benign cardiac
tumors, it worth noting that the use of MI has been described in
literature in the context of primary malignant
tumors26. The MI approach has largely been utilized
with benign tumors rather than malignant tumors probably due to the
greater ease of resection, the less invasive nature of benign tumors,
and the lack of need for very complex cardiac reconstructions, which
would be difficult with MI access.
Sensitivity analysis of the robotic studies was undermined by the
limited sample size; no analysis in terms of survival and relapse at
follow-up could be carried out; while we may conclude that the robotic
approach may be as safe as MS, we cannot validate the long-term results.
A main limitation inherent to the study design stems from the use of
retrospective cohort studies in our pooled analyses. There was a certain
degree of clinical heterogeneity; while most of the studies included
exclusively myxoma at the level of the left or right atrium, others have
included masses at the level of the aortic valve or ventricles.
Follow-up times in this analysis were short with respect to tumor
recurrence/survival and long-term follow-up was not always available.
Finally, no cost-analysis could be performed.