Abstract
Noteworthy in Cardiothoracic Surgery 2024 summarizes a few of the most high-impact trials and provocative trends in cardiothoracic surgery this past year. Specifically, this year saw the release of many in-depth reports comparing the long-term outcomes of transcatheter aortic valve replacement (TAVR) vs surgical approaches for aortic valve replacement, data which is expected to move the transcatheter pendulum. In particular, this included a national analysis of trends reporting the rapid increase of post-TAVR surgical aortic valve replacement (SAVR). This year’s literature also reported ground-breaking milestones related robotics in cardiothoracic surgery, with publication of the first multicenter series of robotic aortic valve replacements, the first entirely robotic double lung and heart transplants, as well as the first combined robotic aortic valve replacement and coronary artery bypass grafting. Specific to lung cancer, data continues to emerge regarding the de-escalation of magnitude of surgical resection from lobectomy to sublobar when able, and in the benefit of immunotherapy in the neoadjuvant treatment of non-small cell lung cancer. Frequent in the literature this year were concerns about toxicity, surgical challenges after therapy, and potential increases in perioperative complications following neoadjuvant chemoimmunotherapy, with calls for surgeons to crucially assess these effects on surgical outcomes to help refine patient selection criteria. Finally, 2024 saw many advancements in intraoperative tumor localization focused on enhancing precision, minimizing invasiveness, and improving surgical outcomes, including robotic-assisted bronchoscopy, electromagnetic navigation bronchoscopy (ENB), and encouraging data regarding intraoperative molecular imaging.
New Data Moving the Transcatheter Pendulum
Transcatheter valve interventions have transformed the management and treatment of pathology involving all four cardiac valves, offering a less invasive alternative to traditional open-heart surgery. One of the most studied interventions, transcatheter aortic valve replacement (TAVR) has expanded the population of patients eligible for valve intervention, as well as replaced surgical valve repair or replacement for many patients who would previously have had surgery as their only option. With advancements in imaging, device technology, and procedural experience, transcatheter interventions continue to redefine cardiac care, prioritizing shorter recovery times, lower procedural complications, and improved quality of life for patients worldwide.
The Rise of Cardiac Surgery Following TAVR
Since the introduction of TAVR in the early 2000s, this field has rapidly expanded. 1 A series of landmark clinical trials evaluated the non-inferiority 1–2 year outcomes of TAVR compared to SAVR in first inoperable or high-risk patients (2010–2011), 2 then intermediate-risk patients (2016–2017), 3 and finally low-risk patients (2019). 4 In 2017, TAVR supplanted SAVR as the most common approach to aortic valve replacement in the United States. 5 Based on the short-term outcomes data in these trials, the 2020 AHA/ACC Valve guidelines were updated to include recommendations on when to consider TAVR over SAVR and vice versa. 6
Given the increased utilization of TAVR, data availability from real-world registries report cardiac operations after initial TAVR, including both SAVR following TAVR and early TAVR explanation, has increased. Published in the Annals of Thoracic Surgery in early 2024, Bowdish et al. 7 documented trends and outcomes of cardiac surgery after initial TAVR using the Society of Thoracic Surgeons (STS) Adult Cardiac Surgery Database, analyzing both non-aortic valve operations and SAVR following TAVR. Over the study period between 2012 and 2023, the frequency of cardiac surgery after TAVR increased 4235.3% overall and 144.6% per year, with a total of 5457 patients identified. Between 2012 and 2019, the increase in post-TAVR surgery was evenly split between SAVR and non-SAVR cardiac surgeries (coronary artery bypass grafting, mitral valve repair or replacement and non-SAVR aortic procedures). However, between 2020 and 2023, TAVR explant followed by SAVR increased at a more rapid rate than operations not involving SAVR. 7
Of particular interest were the 2972 patients who underwent SAVR following TAVR, most commonly for endocarditis and valvular degeneration. Notably, the rapid increase of post-TAVR SAVR was observed after low-risk TAVR approval in 2019, highlighting the question of whether heart teams adequately weigh the longitudinal evidence of SAVR and TAVR in their clinical decision-making. This is of particular importance as the results of this study found that the risk of mortality and major morbidity of a SAVR after TAVR are between 5- and 10-fold higher than with a primary SAVR operation. 7 As TAVR can be performed safely in most centers, patients and providers may naturally gravitate to this option due to non-inferior short-term outcomes, as well as its minimally invasive nature and shorter hospital length of stay. However, life-long valve management and longitudinal (>5 year) implications should be considered by patients and treatment teams.
An early 2024 study by Thourani et al. 8 established the benchmark to which long-term TAVR outcomes may be compared. This group studied patients undergoing isolated SAVR in the STS-database between 2011 and 2019 who met inclusion and exclusion criteria for the two largest and most vigorous TAVR trials, The Placement of Aortic Transcatheter Valves (PARTNER) 3 and Evolut Low Risk.4,9,10 The study demonstrated excellent overall survival of patients undergoing isolated SAVR, with 95.5% 3-year survival, 92.9% 5-year survival and over 87% survival through 8 years. By closely matching the criteria used for the two contemporary low-risk trials comparing TAVR and SAVR, with nearly identical age and STS predicted risk of mortality, Thourani et al.’s study may serve as the new benchmark for current and future trials that may examine long-term TAVR outcomes.
Robotic Milestones in Cardiac and Thoracic Surgery
The evolution of robotics in surgery, and cardiothoracic surgery specifically, represents a remarkable intersection of technology and medicine, revolutionizing the way complex surgical procedures are performed. From its early beginnings in the 1980s with computer-assisted technologies to the ground-breaking introduction of the da Vinci™ Surgical System (Intuitive Surgical, Sunnyvale, CA, USA) in the early 2000s, robotic surgery has steadily advanced in precision, dexterity, applicability, and accessibility. These innovations have enabled minimally invasive approaches to intricate cardiac and thoracic procedures, such as coronary artery bypass, valve repairs, and sublobar anatomic lung resections, significantly improving patient outcomes and recovery times.11,12 While challenges such as cost and the steep learning curve remain, ongoing advancements in imaging, artificial intelligence, and surgical simulation promise an exciting future, further solidifying robotics as a cornerstone of modern cardiothoracic surgery. In 2024 we saw several advancements of the robotic platform in cardiothoracic surgery.
Robotic Aortic Valve Replacement: An Emerging Alternative to TAVR
In January of 2024, Badhwar et al. 13 published the first international series of 212 patients undergoing robotic aortic valve replacement (RAVR), including 30-day outcomes. The series included 71.2% biological prostheses and 28.8% mechanical prostheses, with a median CPB time of 166 minutes and a cross-clamp time of 117 minutes, with no operative conversions to sternotomy. Evaluation of postoperative outcomes demonstrated a median length of stay of 5 days, with 4.7% of patients requiring prolonged ventilation, 1.4% of patients experiencing renal failure, and 0.9% of patients sustaining a stroke. There were two 30-day operative mortalities (0.9%).
Following this series, Jagadeesan et al 14 shared propensity-matched data comparing RAVR and TAVR. The study focused on 288 low- to intermediate-risk patients where the STS predicted risk of mortality was <8%. Patients were matched into RAVR (n = 144) and TAVR (n = 144) groups and the study had several important findings. Primarily, the study demonstrated significantly higher rates of postoperative adverse events in the TAVR group, including higher requirements for new permanent pacemakers (7.6% vs 2.1%, P = 0.028) and vascular complications (9.0% vs 0.0%, P < 0.0001) when compared to RAVR. However, rates of in-hospital mortality were similar (RAVR: 0.7% vs TAVR: 2.1%, P = 0.314), with RAVR patients staying longer (5 vs 2 days, P < 0.0001). After discharge, NYHA class III or IV symptoms at 30 days were present in 9.4% of TAVR patients and 0.0% of RAVR patients (P = 0.014), and significant perivalvular leak at 30 days was higher following TAVR (21.5%) compared to RAVR (0.7%) (P < 0.001). At one year, the data favored RAVR, with lower rates of 1-year mortality (RAVR: 1.3% vs TAVR: 12.5%, P < 0.0001).
Ultimately, these data add to the ongoing discussion regarding the optimal approach to aortic valve replacement in the low- to intermediate-risk patient with symptomatic severe aortic stenosis, for which RAVR may provide a safe and effective minimally invasive alternative to TAVR. In particular, RAVR may be preferable in patients with a bicuspid aortic valve, low coronary heights, significant left ventricular outflow tract narrowing, steep aortic root angles, or high annular calcific burden as these factors may adversely affect TAVR outcomes with respect to durability, second valve options, risk of perivalvular leak, patient-prosthesis mismatch, valvular embolization, stroke, and annular rupture.15-18 Additionally, RAVR allows for the implantation of mechanical prostheses that could offer younger patients advantages in long-term durability and mitigate structural valve degeneration concerns.
Robotic Transplantation
While the first application of robotic-assisted lung transplantation was pioneered by surgeons at Cedars-Sinai Medical Center in early 2022, it was first published in 2024 by Emerson et al. in the Journal of Heart and Lung Transplantation. 19 In this case, a 6-cm open incision was made at the right fourth intercostal space to facilitate the recipient pneumonectomy and then later to insert the whole donor lung into the chest cavity. The da Vinci™ system was then docked for creation of the anastomoses. Following this, the first fully robotic lung transplantation in the United States was performed at NYU Langone Health in October 2024, led by Dr Stephanie H. Chang, where the team used the da Vinci™ system for both the double lung explantation and implantation, for a 57-year-old woman with chronic obstructive pulmonary disease (COPD). 20
Similarly, in 2024 we saw the first fully robotic heart transplant led by Dr Feras Khaliel and his heart team at King Faisal Specialist Hospital and Research Center (KFSHRC) in Riyadh, Saudi Arabia. Amazingly, the procedure lasted roughly two and half hours, and was performed on a 16-year-old patient with end-stage heart failure. 21 Additional details are limited as the full case has not been published, but has led to increased optimism in the surgical community regarding the application of robotics in cardiothoracic surgery. This sentiment is echoed in another first in 2024, where surgeons at the West Virginia University Heart and Vascular Institute, led by Dr Vinay Badhwar, performed the world’s first combined robotic aortic valve replacement and coronary artery bypass grafting in October of 2024 for a 73-year-old woman with reports of a successful surgery and rapid recovery. 22 The cardiothoracic surgical community anxiously awaits the formal publication of these landmark cases as we seek to expand the utilization of robotics in cardiothoracic surgery.
A Shift Toward Sublobar Resections for Lung Cancer
Historically, lobectomy, was considered the gold standard for the surgical treatment of non-small cell lung cancer (NSCLC), as it was believed to offer the best chance for long-term survival. However, recent advancements in early detection, imaging, and surgical techniques have prompted a shift towards sublobar resections, such as segmentectomy and wedge resection. A 2024 systematic review of sublobar resection by Merrit et al. found that use of sublobar resection for the management of stage I NSCLC has demonstrated comparable oncologic outcomes and complication rates as lobectomy.
In particular, they examined randomized trials comparing sublobar resection with lobectomy in patients who were candidates for lobectomy. This is notable as previously sublobar resections were only utilized in patients with compromised lung function or other comorbidities. The CALGB 140503 trial 23 demonstrated that sublobar resections can offer survival outcomes comparable to lobectomy for early-stage, small tumors, particularly those less than 2 cm in size and without lymph node involvement. Similarly, the JCOG 0802 trial, 24 demonstrated there were no significant differences in 5-year relapse-free survival, citing 88.0% for segmentectomy and 87.9% for lobectomy.
Until more definitive data emerges, we must also rely on expert consensus opinions to guide management. For example, the Thoracic Surgery Outcomes Research Network (ThORN) Consensus Document on Defining a High Quality Wedge Resection for Early Stage Lung Cancer was recently published. 25 The work was classified into five categories: (1) Preoperative Considerations; (2) Technical Aspects; (3) Lymph Node Assessment; (4) Margin Assessment; and (5) Tissue Handling by Pathology. Overall, the group cautioned that the excellent outcomes observed in the CALGB 140503 trial for patients in the wedge resection cohort could largely be attributed to the surgeons’ strong clinical judgment in selecting appropriate candidates for wedge resection rather than segmentectomy. In practice, not every clinical decision can be validated through randomized clinical trials, and the real-world, point-of-care decision-making of the surgeon remains crucial.
Similar sentiments were discussed in the October 2024 STS expert consensus statement on the multidisciplinary management and resectability of locally advanced NSCLC. 26 Here, the STS emphasized that the management of locally advanced NSCLC requires a comprehensive, multidisciplinary approach to determine the best treatment strategy for each patient. This includes careful assessment of resectability, consideration of neoadjuvant (including perioperative) and adjuvant therapies, and collaboration among thoracic surgeons, medical oncologists, and radiation oncologists. The document provided updated insights based on the latest literature and clinical experience, focusing on the appropriateness of surgical therapy and emerging data regarding neoadjuvant and adjuvant therapies.
Surgical Implications of Neoadjuvant Immunotherapy for Lung Cancer
Over the past decade, lung cancer treatment has experienced a paradigm shift. Advances in understanding lung cancer biology have driven the development of highly effective targeted therapies and immunotherapies. Immune checkpoint inhibitors, in particular, have demonstrated remarkable benefits in treating non-small cell lung cancer (NSCLC). In a 2024 meta-analysis of eight randomized-control trials examining the effect of neoadjuvant immune checkpoint inhibitors plus chemotherapy for patients with early-stage non-small cell lung cancer (NSCLC), Banna et al. 27 reported consistent associations between the addition of immunotherapy and improved event-free survival and pathologic complete response rates. Following the demonstrated success of these therapies, including Nivolumab and Pembrolizumab, there has been rapid adoption of their use. Immune checkpoint inhibitors are now utilized as first-line options for metastatic disease, as consolidation therapy after chemoradiation for unresectable locally advanced cases, and as adjuvant treatment following surgical resection and chemotherapy for resectable cases.
While the usefulness of immunotherapy in the neoadjuvant setting has shown promising results regarding pathological response rates, more recently questions have been raised regarding toxicity, surgical technical challenges after treatment, and a potential increase in perioperative surgical complications following neoadjuvant therapy. These concerns were summarized in a 2024 “Controversies in Thoracic Oncology” article by Figueroa et al. 28 The authors began by cross examining four carefully performed, randomized clinical trials for neoadjuvant therapy for resectable stage II to III NSCLC: CheckMate-816, 29 Keynote-671, 30 Aegean, 31 and NeoTORCH. 32 Briefly, CheckMate-816 assessed neoadjuvant Nivolumab plus chemotherapy vs chemotherapy alone, demonstrating improved pathological complete response (pCR) rates and event-free survival (EFS) with the combination therapy. Similarly, the KEYNOTE-671 trial evaluated Pembrolizumab added to neoadjuvant and adjuvant chemotherapy, showing significant improvements in pCR and EFS, underscoring its potential in multimodal treatment. The AEGEAN trial investigated Durvalumab combined with neoadjuvant chemotherapy followed by adjuvant Durvalumab, which also yielded improvements in pCR and EFS, supporting its inclusion in therapeutic protocols. Finally, the NeoTORCH trial examined Toripalimab with chemotherapy in the neoadjuvant setting, revealing higher pCR rates and a favorable safety profile, further validating the efficacy of this combination. Collectively, these studies highlight the transformative role of immunotherapy in advancing the treatment of resectable NSCLC.
In their review article, Figueroa et al. called into question whether the benefits of chemoimmunotherapy with respect to pCR and EFS should be balanced with their implications on subsequent surgical resection. First, the authors noted the not-infrequent occurrence of cancellation of surgery after reception of neoadjuvant chemoimmunotherapy: across the four trials, serious secondary adverse events occurred after neoadjuvant treatment in 15% to 63% of patients, which is notable as adverse events can interfere with treatment completion including continuing to surgery. In fact, only 40% to 71% of patients completed treatment across these trials, with 16% to 22% of patients not undergoing resection of NSCLC as planned at the outset of treatment.
Figueroa et al. also raised the concern of the completeness of resection, the type of resection performed, and whether the surgery was converted from a minimally invasive approach to a thoracotomy to serve as an indicator of surgical technical difficulty after immunochemotherapy. It should be noted that none of the major phase 3 clinical trials included a thorough evaluation of technical challenges encountered during resection after neoadjuvant immunotherapy treatment. However, other studies have done so. Bott et al. 33 reported surgical outcomes for 20 patients who underwent chemoimmunotherapy with Nivolumab followed by resection, with conversion to thoracotomy occurring in 25% of patients with stage I, 50% with stage IIA, and 71% with stage IIB or IIIA NSCLC, primarily due to inflammatory responses, including dense adhesions and fibrosis at the fissure and surrounding hilar and mediastinal nodes. Similarly, Baek et al. 34 observed fibrotic changes and adhesions in all patients undergoing resection after treatment with immunotherapy, particularly in the fissure and interlobar lymph nodes. Overall, these results suggest that surgeons and operative teams should have increased awareness for the possibility of conversion from robotic to open approach in patients who have received immunotherapy prior to operative intervention.
Overall, the adoption of neoadjuvant chemoimmunotherapy as a standard care strategy for resectable NSCLC remains uncertain. Currently, upfront surgery followed by tailored adjuvant systemic therapy is often preferred for patients without N2 lymph node involvement, partly due to recent advancements in adjuvant therapies and resistance to drastic changes in surgical practices. We look forward to more real-world data to assess the practical impact of neoadjuvant chemoimmunotherapy, including its effects on lymphadenectomy, upstaging rates, and surgical challenges. In addition, a direct comparison of neoadjuvant vs adjuvant chemoimmunotherapy could clarify which patients benefit most from each approach. As surgical challenges post-immunotherapy are better understood, the question persists whether the field is ready for widespread adoption of neoadjuvant chemoimmunotherapy for early-stage, resectable NSCLC.
Advances in Intraoperative Localization of Lung Tumors
Recent advancements in intraoperative tumor localization for lung cancer have focused on enhancing precision, minimizing invasiveness, and improving surgical outcomes. Among the most notable recent developments include advancements in robotic-assisted bronchoscopy, namely, the Ion Endoluminal System™ (Intuitive Surgical, Sunnyvale, CA, USA), Monarch Platform™ (Johnson & Johnson, Redwood City, CA, USA), and Galaxy System™ (Noah Medical, San Carlos, CA, USA), aimed at improving the accuracy and safety of diagnosing and localizing lung nodules, particularly in early-stage lung cancer. This year, several studies emerged providing narrative reviews of the technology and early supporting data.
The Ion™ Endoluminal System is designed for minimally invasive lung biopsies and features a thin, flexible catheter equipped with shape-sensing technology that provides real-time feedback on its position within the airway to optimize endoluminal biopsies of lung nodules. Fernandez-Bussy et al.’s 35 2024 review of the existing literature found a navigational success rate between 96.6% and 98.7% and a diagnostic yield ranging from 79.3%–84.8% with minimal complications. Similarly, the Monarch™ Platform uses electromagnetic navigational bronchoscopy (ENB) to track the bronchoscope’s position, enabling accurate access to peripheral lung areas. ENB has emerged as a valuable tool, particularly for accessing peripheral or subcentimeter lesions that are otherwise challenging to palpate. When combined with dye marking or fiducial placement, ENB provides a reliable method for guiding resection.
The Navigation of video-assisted thoracoscopic surgery using electromagnetic vs CT-guided localization (NOVEL) trial protocol was introduced in 2024. 36 NOVEL is an active, multicenter, randomized, controlled, non-inferiority phase III study designed to compare the safety and efficacy of ENB-guided localization with traditional computed tomography (CT)-guided localization for small pulmonary nodules prior to video-assisted thoracoscopic surgery. Primary outcomes include procedural success rates and complication rates for both techniques, while secondary outcomes assess procedure times and lesion margins. As of now, the NOVEL trial is ongoing, and specific results comparing the two localization methods have not yet been published. The study’s findings are anticipated to provide valuable insights into the relative advantages and potential limitations of ENB-guided vs CT-guided localization techniques, potentially influencing future clinical practices in the localization of small pulmonary nodules. Similarly, the Transbronchial Biopsy Assisted by Robot Guidance in the Evaluation of Tumors of the Lung (TARGET) study 37 is an ongoing multicenter prospective trial aimed at evaluating the safety and diagnostic accuracy of Monarch Platform™. The TARGET study is expected to provide strong evidence supporting the adoption of robotic bronchoscopy as a standard approach for diagnosing lung cancer, offering a safer and more precise alternative to percutaneous or surgical biopsies.
Noteworthy Cardiothoracic Surgery Articles From 2023.
Abbreviations: SAVR, surgical aortic valve replacement; TAVR, transcatheter aortic valve replacement; RAVR, robotic-assisted aortic valve replacement; NSCLC, non-small cell lung cancer; ICI, immune checkpoint inhibitor; CT, computed tomography.
Footnotes
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) received no financial support for the research, authorship, and/or publication of this article.
Disclosure
RAM reports that he consults for Medtronic, Inc.
