As is customary in the Thoracic and Cardiovascular Surgeon, and consistent with its tradition over the past decade, once again they provide a summary of the most interesting and significant articles in cardiac surgery for the year 2022. In this blog entry, our objective is to provide a coherent and structured account of these highlighted studies from 2022 and to attempt to emphasize in the commentary the most relevant conclusions of these studies, while also outlining some of the new trends in cardiac surgery that emerged throughout 2023. Given the abundance of evidence and the complexity of synthesizing it without losing essential information, this article will exceptionally have a longer length than usual. The innovations and trends in 2023 are based on selected articles and were exhaustively analyzed week by week in our blog “Cirugía Cardíaca Hoy,” allowing us to offer a contextualized analysis of the research from the previous year.
– Ischemic Heart Disease:
In 2022, two prominent clinical trials raised concerns regarding the impact of invasive treatments on chronic coronary syndrome. One of these was the ISCHEMIA trial, which showed no improvement in survival with invasive diagnosis and treatment in symptomatic patients with inducible ischemia under medical management. The other was the REVIVED study, which demonstrated that percutaneous coronary intervention (PCI) had no significant impact on survival compared to medical treatment in patients with ischemic heart failure (ejection fraction equal to or less than 35%) and inducible ischemia. It is important to note that the invasive arm of the ISCHEMIA study included a minimal percentage of patients undergoing coronary artery bypass grafting (CABG). Grouping CABG and PCI under the generic term “revascularization” is unhelpful in this context, as both methods use completely different revascularization mechanisms, and their outcomes vary considerably depending on the context, as demonstrated repeatedly in the literature.
Interestingly, during 2022, cardiology literature tended to downplay the proven efficacy of CABG (compared to PCI) in improving survival for most patients with left main coronary artery disease (LMCA) and triple-vessel disease, particularly those with complex coronary anatomy, or in other words, with an intermediate or high Syntax SCORE.
In this regard, a meta-analysis conducted by Gaudino et al. in the same year, based on contemporary clinical trials and encompassing a total of 2,523 patients (all receiving at least aspirin, statins, and beta-blockers), reaffirmed findings established over 30 years ago (when optimal medical treatment was not yet available): improved survival with CABG compared to PCI.
Furthermore, in 2022, evidence continued to accumulate regarding the benefits of medical treatment in the context of CABG. For instance, a sub-analysis of the ticagrelor clinical trial in CABG, published by Heer et al., revealed that optimal medical therapy reduces morbidity and mortality. Another meta-analysis, which included four clinical trials, demonstrated that the use of ticagrelor in the postoperative period after CABG improves graft patency, though with the drawback of an increased bleeding risk.
Senior et al., after analyzing the ISCHEMIA trial population, concluded that stress testing alone is insufficient to detect LMCA disease, highlighting the necessity of anatomical imaging tests. Meanwhile, Ono et al. suggested that the presence of proximal lesions in the left anterior descending artery in SYNTAXES trial patients should not influence the selection between PCI or CABG. However, Ninomiyha et al. demonstrated that CABG is superior to PCI for bifurcation lesions. In a sense, the advantage of CABG over PCI does not stem from addressing an isolated lesion but from mitigating the overall risk of coronary events, as Gaudino et al. demonstrated in another meta-analysis. In other words, if the risk of coronary events is high, CABG is superior to PCI, whereas if the risk is low, PCI is not inferior. This hypothesis has been tested repeatedly in the evidence and cannot be ignored.
Caldonazo et al. demonstrated a significant advantage in mortality and long-term major events with CABG compared to PCI by analyzing the most relevant registries from 18 different countries, without finding significant differences in periprocedural mortality. These results are, moreover, consistent with previously published clinical trials. Additionally, very similar outcomes were replicated in the study by Derrick et al., who compared CABG with PCI in left main coronary artery disease among Canadian patients with chronic coronary disease through propensity score analysis.
In specific cases of acute coronary syndromes, CABG has also recently shown benefits over PCI, as observed in diabetic patients in the study by Ram et al. A similar survival benefit was found in the study by Rocha et al. in patients with multivessel disease treated with CABG. Additionally, the meta-analysis by Tasoudis et al. corroborated this benefit, this time in patients on dialysis.
Although CABG’s reiterated superiority over PCI is mostly observed in clinical registries, with the inherent biases these entail, the overwhelming amount of studies supporting CABG and the scarcity of studies in favor of PCI underscore the importance of making decisions in consensus with the Heart Team. This consensus approach is essential to counteract the documented tendency to favor PCI in centers lacking a systematically implemented Heart Team with cardiac surgery representation, as demonstrated by El-Andari et al. in an interesting Canadian study that same year.
There is no doubt that optimizing CABG outcomes requires maintaining graft patency. In a post hoc analysis of the COMPASS study, Alboom et al. reported a higher-than-expected graft failure rate of the right internal thoracic artery (27% within a year of surgery), detected by computed tomography. Conversely, a retrospective study reaffirmed the excellent results of the radial artery as a second graft option. Gaudino et al., analyzing data from the four largest clinical trials, concluded that the radial artery as a second graft is superior to the saphenous vein or the right internal thoracic artery. To clarify this topic, Urso et al., in a dual meta-analysis, demonstrated that using a bilateral internal thoracic artery is superior to a combination of internal thoracic and radial arteries, although significant differences only emerge after more than 10 years of follow-up. Other authors, like Doenst et al., also emphasized that surgical precision and experience in performing anastomoses may play a role as crucial as graft type selection.
– Aortic Valve Disease:
Following the publication of the new valve disease guidelines in 2021, the advancement of transcatheter aortic valve implantation (TAVI) over surgical aortic valve replacement (SAVR) for severe aortic stenosis (AS) gained momentum. In 2022, Myer et al. published a position statement from surgical societies highlighting the strengths and limitations of the VARC 3 definitions.
The only randomized study that compared TAVI with SAVR was the UK TAVI trial, which found no significant differences in 1-year mortality between the groups when analyzing patients over 70 years with moderate risk, reinforcing the evidence for equally favorable or slightly better short-term outcomes with TAVI. In another original study, Chung et al. showed that high-risk patients with CoreValve spent more time at home (an additional 4 weeks in the first year) compared to those who underwent surgery, with no other significant differences after 4 years of follow-up.
In summary, it appears well established that SAVR results in slightly higher transvalvular gradients and an increased incidence of atrial fibrillation, while TAVI procedures are associated with a greater need for pacemaker implantation, a higher tendency for thrombosis (with clinically uncertain implications in many cases), more paravalvular leakage, and possibly slightly lower long-term survival. In this regard, in 2022, a Polish registry showed better 5-year survival with SAVR but equally favorable or slightly better short-term results with TAVI. These findings confirm results previously observed in German, Italian, and French registries. However, a post hoc analysis by O’Hair et al. of patients from three intermediate- to high-risk trials (U.S. CoreValve High Risk Pivotal, SURTAVI, and CoreValve Extreme Risk Pivotal) revealed that structural valve degeneration (SVD) at 5 years was lower with TAVI than with surgical bioprostheses. Therefore, the potential survival difference favoring SAVR likely results from a combination of factors rather than a single one. Given these results, along with the guidelines that set an arbitrary age threshold of over 75 years for TAVI and under 75 years for SAVR in low-risk patients, it is crucial to adopt a flexible approach, considering individual patient characteristics within the context of the local Heart Team.
In patients with mild to moderate renal insufficiency, studies such as the GARY registry found no differences between TAVI and SAVR after five years. Other studies, such as the PROTECTED TAVR trial, showed no reduction in stroke incidence with TAVI when using embolic protection devices.
The AVATAR clinical trial demonstrated improved morbidity and mortality outcomes in asymptomatic patients with severe aortic stenosis who underwent surgical treatment compared to conservative management.
Other authors have focused on specific complications. Fukui et al. demonstrated that TAVI bioprostheses undergoing deformation during implantation represent a risk factor for prosthetic thrombosis, also referred to as hypoattenuated leaflet thickening (HALT).
On the other hand, Squiers et al., through a meta-analysis, demonstrated that the Carpentier Edwards® Magna Ease® surgical bioprosthesis has greater durability than the Mitroflow®/Crown® or St. Jude Trifecta® bioprostheses. The St. Jude Trifecta® valve, specifically, was withdrawn from the market the following year due to its high risk of SVD after 5 years. In any case, the study suggests that it is not simply whether the prosthesis is porcine or bovine pericardial but rather the specific design characteristics of each prosthesis that determine the long-term performance of a bioprosthesis. These positive results for the Carpentier Edwards® Perimount® bioprosthesis (predecessor of the Carpentier Edwards® Magna Ease®) were confirmed in the Swedish SWEDEHEART registry, which analyzed nearly 17,000 patients with surgical bioprostheses. Lastly, Sotade et al. demonstrated similar outcomes when comparing biological and mechanical valves in patients aged 55 to 64 years over a 10-year follow-up; however, with longer follow-up, mechanical valves showed a mortality advantage, likely due to a reduced incidence of reoperations.
The Ross procedure was evaluated in two studies in 2022, with an average patient age of 40 years. In the study by El-Hamansy et al., superior survival and lower incidence of valve-related complications at 15 years were observed in patients undergoing the Ross procedure, after matching this group with those receiving mechanical and biological prosthetic aortic valve replacements. In another study by Mazine et al., these same differences were found when comparing the Ross procedure with bioprostheses. Therefore, these two publications reaffirm that the Ross, once considered a high-risk option, is now a feasible and real alternative.
A similar shift has occurred in aortic valve replacement reoperations, which carried nearly a 4% risk in the 1980s. Studies like the one by Mahboubi et al. currently place this risk at 1.3%, a level comparable to primary intervention for a native aortic valve. This is an important consideration for Heart Teams in decision-making for these patients.
– Mitral Valve Disease:
As with the aortic valve, direct comparisons between interventional and surgical treatments for the mitral valve have become increasingly rare over the past two years, aligning with established clinical guidelines and the drastic reduction in surgical indications. In a meta-analysis by Nappi et al., which evaluated the impact of 12 clinical trials on the invasive treatment of functional mitral regurgitation (MR), it was concluded that functional MR is a complex entity in which MitraClip® only reduces hospital readmissions compared to medical treatment. However, in a retrospective study, Sannino et al. found no significant improvement in MR when comparing MitraClip® with conservative treatment, but they did observe better survival in patients who no longer had severe MR, regardless of the treatment type. Similar results were obtained a year earlier in a two-year analysis of the COAPT study. Both studies suggest that durable elimination of MR, irrespective of the mechanism or treatment modality, appears to offer the greatest potential to increase survival.
Conversely, surgical mitral repair continues to show superior outcomes in terms of survival compared to mitral valve replacement, as reflected in two publications from 2022. Other studies also showcase the relentless progress in the surgical field of the mitral valve. Sabatino et al. demonstrated that it is possible to safely discharge selected patients three days postoperatively. Additionally, other studies reinforce the excellent long-term results of surgical mitral repair for structural MR. Increasingly, research confirms the trend toward non-sternotomy approaches with favorable results, though robotic surgery does not demonstrate a significant improvement in pain management.
– Tricuspid Valve Disease:
Undoubtedly, the most relevant publication in 2022 was the CTSN Tricuspid trial, in which 401 patients were randomized to concomitant tricuspid annuloplasty versus isolated mitral valve surgery in patients with mild to moderate tricuspid regurgitation (TR). The study demonstrated greater freedom from TR progression in the tricuspid annuloplasty group, though at the cost of a higher incidence of pacemaker implantation (2.5% vs. 14.1%). Other publications also emphasized isolated TR, increasingly recognized as a more harmful condition than previously thought.
Russo et al. suggested that isolated tricuspid surgery, performed on a beating heart, is associated with improved survival. Additionally, new predictive scales for prognosis in tricuspid surgery have begun to emerge. Färber et al. demonstrated that the MELD score (Model for End-Stage Liver Disease) with a score above 20 points is a much better predictor of mortality than traditional cardiac surgery scores. Meanwhile, Dreyfus et al. proposed the TRI-SCORE with exactly the same objective.
– Aortic Diseases:
In 2022, multiple publications pointed to the positive outcomes associated with frozen elephant trunk techniques in aortic dissection surgery, especially in specialized centers and in younger patients with specific anatomical criteria.
In terms of alternative treatments, a retrospective series from Italy reported on high-risk type A aortic dissection patients treated using aortic wrapping with Teflon sheets, without the use of extracorporeal circulation. This study demonstrated an acceptable short-term mortality rate (9%) and very favorable three-year outcomes (83% survival), suggesting this less invasive approach could be viable for borderline patients, particularly those with limited life expectancy.
In the context of malperfusion syndrome, a meta-analysis revealed improved outcomes when revascularization was performed prior to aortic repair surgery, compared to an approach prioritizing aortic repair first. This may signal a paradigm shift from current practices.
– Advanced Heart Failure (AHF):
In the field of advanced heart failure, 2022’s highlight was undoubtedly the first xenotransplant performed on a 57-year-old patient using a genetically modified pig heart. However, after the initial days, the patient required mechanical circulatory support and ultimately passed away 60 days later, with cytomegalovirus infection suggested as the primary cause. This milestone opens the door to an unexplored path.
Regarding long-term left ventricular assist devices (LVADs), the MOMENTUM3 trial provided a new tool, the HM3 score, which appears to accurately predict outcomes for these patients, facilitating future decision-making.
COMMENTARY:
– Ischemic Heart Disease:
Summarizing the 2022 publications in this field, we can conclude that:
– Evidence supporting coronary surgery as the gold standard for treating coronary artery disease, especially in cases of multivessel and/or high anatomical complexity, continues to grow.
– Among patients selected for CABG worldwide, long-term survival appears superior to those treated with PCI, regardless of geographic location. Importantly, there seems to be no difference in 30-day mortality between CABG and PCI in risk-adjusted patients.
– Graft patency is essential for achieving the benefits of CABG treatment. In 2022, evidence favoring the radial artery as the best second graft continued to accumulate, and long-term patency of the right internal thoracic artery was called into question.
Furthermore, the accumulated evidence in 2023 does not contradict the previous year’s findings and offers new insights:
– Following the controversial REVIVED study in 2023, new reviews evaluated revascularization in ischemic dilated cardiomyopathy. Although the role of viability studies remains unclear, complete revascularization and next-generation optimal medical therapy (OMT) are essential for improving prognosis in these patients.
– In 2023, a substantial amount of information regarding coronary grafts was again accumulated, reaffirming the preference for arterial grafts and an individualized revascularization strategy, as reflected in the consensus document published by EACTS and STS on the indications and surgical management of various graft types in coronary artery bypass surgery.
– Additionally, numerous articles confirm the ongoing advancement of coronary surgery as a primary option for LMCA disease, with PCI downgraded to a class IIa recommendation for SYNTAX scores below 22.
– In 2023, further significant publications recommended surgical revascularization for coronary arteries with patent stents, particularly if the stents are non-drug-eluting, showing that graft patency is unaffected when revascularizing an occluded right coronary artery. The trend toward hybrid revascularization was addressed last year, highlighting favorable outcomes. Consensus documents on revascularization in stable coronary artery disease proved highly practical and useful. Furthermore, evidence continued to accumulate in the field of mechanical complications; for instance, the importance of ECMO in the management algorithm for ventricular septal defects was confirmed in most European hospitals with cardiac surgery units.
– Aortic Valve Disease:
Perhaps the most relevant takeaway from 2022 is that in the treatment of severe aortic stenosis, TAVI yields similar or slightly better short-term results compared to SAVR, while the latter has fewer long-term complications and possibly better five-year survival. In younger patients, the Ross operation may offer superior long-term outcomes compared to SAVR, primarily due to a lower incidence of valve-related complications.
With the 2023 publications in mind, we could add that the expansion of sutureless surgical prostheses continued to show favorable results, with lower pacemaker implantation rates and excellent overall performance, and their use in combined surgeries now seems well-established. The elevated risk associated with surgical intervention in patients with a prior TAVI (with mortality above 10%) has also been increasingly recognized, an adjustment we will inevitably need to make.
Regarding TAVI, there has been an extensive volume of publications. Some continue to emphasize the poor prognosis associated with paravalvular leaks (even minor ones) and the need for pacemaker implantation post-implant. Other authors describe acceptable results with TAVI in bicuspid valves and even in cases of aortic insufficiency. There is also growing evidence on the good results of non-transfemoral TAVI (an area in which surgeons have a significant role to play), especially the transcarotid approach.
In low-risk patients, the three-year favorable outcomes of the Evolut Low-Risk trial for TAVI and the five-year favorable outcomes of the PARTNER 3 trial for surgery will undoubtedly shape future meta-evidence and clinical guideline recommendations. Additionally, studies with positive outcomes for redo-TAVI (valve-in-valve) have begun to emerge, establishing it as a real option that expands the decision-making spectrum for patients with dysfunctional percutaneous prostheses.
– Mitral Valve Disease:
In summary, in the field of mitral surgery during 2022, the evidence supported the concept that the most significant long-term benefits, including survival, are associated with the degree of MR reduction and the durability of the repair, regardless of treatment type.
In 2023, the five-year outcomes of the COAPT study confirmed the trend toward clinical improvement and reduced mortality that had already been observed in the initial 48-month study on MitraClip® compared to OMT in patients with moderate-to-severe secondary MR. Other publications delved into a better understanding and classification of primary MR, clearly differentiating five phenotypes.
In strictly surgical terms, additional evidence accumulated in 2023 supporting left ventricular reverse remodeling with any type of mitral repair. Large case series with the Commando operation position this technique as a feasible and definitive solution for surgically addressing complex diseases of the fibrous skeleton of the heart. Moreover, the mitral valve-in-valve option was established as a viable alternative in cases of degenerated bioprostheses, and the open surgical implantation of balloon-expandable valvular prostheses for severe mitral annular calcification may now provide a solution for previously inoperable cases.
– Tricuspid Valve Disease:
Summarizing 2022 in this field, growing evidence supports concomitant treatment of TR during cardiac surgery, as this seems to prevent its progression, although at the cost of a higher incidence of pacemaker implantation. Additionally, isolated TR surgery shows that perioperative risk is influenced by the degree of systemic congestion, where liver function plays a significant role. Surgery performed on a beating heart could offer benefits and mitigate risks concerning early postoperative right ventricular function.
In 2023, the most relevant publications continued along the same lines, with increasing attention given to isolated TR, an aspect previously less emphasized. The importance of early surgery for severe isolated TR has been highlighted more and more, along with new and more comprehensive classifications of TR and the application of VARC criteria to standardize the results of invasive treatments. Additionally, the increasingly utilized TRI-SCORE appears to accurately assess the risk-benefit balance of invasive treatment options versus conservative management. Meanwhile, the MELD score has proven useful in risk assessment, as traditional risk stratification systems have limited predictive capacity, particularly in cases of secondary hepatic dysfunction.
Finally, in 2023, new insights emerged regarding percutaneous procedures. The TRILUMINATE study concluded that edge-to-edge transcatheter tricuspid valve repair (TTVR) in severe TR reduces TR grade and is associated with improved quality of life, suggesting a growing role for interventional treatment in this field.
– Aortic Disease:
During 2023, evidence continued to accumulate, reinforcing findings from the previous year and further supporting the suitability of frozen elephant trunk techniques for specific patients. However, an even greater emphasis has been placed on the importance of a personalized strategy for managing type A aortic dissections. Additionally, significant publications continued to support the growing trend toward using TEVAR for non-complicated type B aortic dissections. The importance of the TEM classification in decision-making for these patients has been underscored, reflecting the complexity of acute aortic pathology as a whole.
Other studies provided new insights into various surgical strategies and neuroprotection techniques in aortic arch surgery, among many other innovations.
– Advanced Heart Failure:
In addition to the xenotransplant performed in 2022, the year 2023 marked a significant exploration of innovative and impactful topics in the field of transplantation, highlighting the excellent outcomes achieved in both national and international transplants from controlled donation after circulatory death (DCD) donors. Moreover, the implementation of new prioritization criteria on the waiting list in Spain has reshaped the landscape of transplants, as previously discussed. Evidence continues to support expanding the donor pool, including donors with a history of hepatitis C (HCV) positivity.
In 2023, research continued to expand the bibliography supporting both the short- and long-term benefits of durable assist devices, reaffirming their status as indispensable devices. Additionally, numerous publications have reinforced the utility, appropriate use, and excellent outcomes of veno-arterial ECMO, particularly in cases of cardiogenic shock or secondary to myocardial infarction. These devices, increasingly common in our practice, have become integral to our clinical approach.
As we can see, cardiac surgery, much like other specialties, is closely linked to technological and scientific developments. Mahatma Gandhi once said that “technology becomes a tool when it reaches the hands of people capable of doing extraordinary things.” In our clinical practice, these devices serve as the fundamental instruments enabling us to perform extraordinary acts directly benefiting our patients.
REFERENCE:
Doenst T, Schneider U, Caldonazo T, Toshmatov S, Diab M, Siemeni T, Färber G, Kirov H. Cardiac Surgery 2022 Reviewed. Thorac Cardiovasc Surg. 2023 Aug;71(5):356-365. doi: 10.1055/s-0043-57228.
