There are numerous approaches to minimally invasive CABG, the most common of which is MIDCAB, which accounted for 46.9 percent of minimally invasive procedures performed between 1996 and 2019. Meanwhile, robotic MIDCAB represents 15.8% of these procedures. Other variations of minimally invasive CABG include totally endoscopic CABG (TECAB) and robotic TECAB [1].

MIDCAB typically involves a mini-left thoracotomy with stabilization of the target vessel on the beating heart. The single graft is typically the left internal mammary artery (LIMA); however, the right internal mammary artery (RIMA) can also be harvested, requiring an average of 28.5 minutes compared with 22.2 minutes for LIMA harvesting [1, 2]. The 5-year survival rate was similar at approximately 91% [3]. Video-assisted MIDCAB is performed with the patient in the right lateral decubitus position. The LIMA is then harvested through two thoracoscopic ports, and the anastomosis is completed via a left mini-thoracotomy. LIMA harvesting times are nearly twice those of conventional MIDCAB, adding roughly an hour to the total operating time. Across several studies, operative times ranged from 2 to 5.3 hours [4, 5, 6, 7, 8].

Robotic MIDCAB similarly uses a camera port and two instrumental ports in conjunction with a mini-thoracotomy. It has been reported to require an average of 4 hours per graft, most commonly using the LIMA [1]. Meanwhile, postoperative complication rates are comparable to those of non-robotic MIDCAB, although the conversion rate to a larger incision is higher (6.6% versus 1.7%). Robotic MIDCAB has been associated with a reduction in length of stay by approximately 4 days and a similar 5-year survival rate (94%) compared with sternotomy.

On-pump CABG via a mini-thoracotomy is similar to MIDCAB but uses cardiopulmonary bypass established through peripheral vessels, typically the femoral artery and vein. Although this exposes the patient to cardiopulmonary bypass, the technique eliminates the challenges of beating-heart bypass and provides improved exposure by unloading the heart. Although operative times are similar to MIDCAB, with IMA harvesting times comparable to those of video-assisted MIDCAB, some surgeons were able to perform an average of three bypasses in a single operation [9].

TECAB eliminates the need for a mini-thoracotomy, with camera and instrument ports positioned similarly to those in robotic MIDCAB. TECAB is reportedly technically challenging but the least invasive option, with a reported conversion rate to a larger incision of up to 45.1% and longer LIMA harvesting times (average of 77 minutes) [10, 11]. Robotic TECAB uses a robotic platform similar to that used for MIDCAB but without a sternotomy. Notably, robotic assistance has facilitated the effective application of TECAB by improving IMA harvesting times, 55 minutes for the LIMA and 32 minutes for the RIMA [12]; meanwhile, the mean number of bypass grafts per procedure was 1.4. The conversion rate to a larger incision has been reported at 10.3%, and the 3-year survival approached 96% [13, 14].

Minimally invasive coronary artery bypass has been shown to decrease hospital stay and eliminate the exposure to the potential complications associated with cardiopulmonary bypass. Although patients generally prefer the least invasive approach, there remains significant potential for conversion to a sternotomy, and broader applicability to the general population is limited by the experience of the surgeon with the robot. Existing studies on minimally invasive coronary artery bypass are not randomized for direct comparison with sternotomy. Furthermore, these approaches are generally limited to high-volume, specialized centers that offer a specific approach, which prevents adequate comparison across different types of minimally invasive procedures. Moreover, controlling patient-specific factors that can significantly affect postoperative outcomes, such as the extent of coronary artery disease and the experience of the surgeon using minimally invasive approaches, is challenging. Therefore, these procedures may be more likely to be offered to lower-risk operative candidates.

Given that operative times for robotic MIDCABG are longer than those for sternotomy, proponents have advocated a hybrid approach combining minimally invasive coronary bypass with percutaneous coronary intervention (PCI), which can offer similar postoperative benefits, including reduced hospital length of stay, infection rates, and ventilator time. The argument for hybrid coronary revascularization is supported by evidence of superior 1-year patency with the newest drug-eluting stents compared with saphenous vein grafts (95% versus 80%) [15]. Hybrid revascularization offers survival rates (99%) and stroke rates (1%) similar to those of traditional coronary bypass, with a shorter length of stay [16].

However, hybrid revascularization is limited to carefully selected patients, typically those with complex left anterior descending artery disease and focal right coronary and circumflex artery disease suitable for stenting. Although MIDCABG can be performed either before or after PCI, some argue for performing MIDCABG before PCI to avoid the increased risk of bleeding associated with antiplatelet therapy. The HREVS trial compared hybrid revascularization with PCI and traditional CABG, using a protocol in which MIDCABG was performed 3 days before PCI and Plavix was initiated on the day of PCI [17]. Hospital length of stay was similar between the hybrid and sternotomy groups. There was no significant difference in repeat revascularization at 1 year among groups, although the CABG group had the lowest rate of repeat revascularization and a significantly higher bleeding rate. The POLMIDES study compared the hybrid strategy with CABG and found similar 12-month rates of survival, myocardial infarction, and repeat revascularization [18], with comparable bleeding between groups. Ding et al. [19] compared off-pump CABG with PCI and simultaneous hybrid revascularization, and found that hybrid therapy was associated with longer operative times and a higher cumulative 10-year repeat revascularization rate. The authors attributed these findings to higher SYNTAX scores and longer follow-up in their study population.

Although the operative costs of hybrid PCI are higher than those of traditional CABG, decreased ventilation and intensive care unit (ICU) length of stay, along with reduced postoperative length of stay, may offset these costs [20]. Since hybrid PCI and CABG account for only 0.48% of CABG volume, further research on outcomes is needed to clarify the postoperative benefits and cost-effectiveness of robotic and hybrid revascularization, particularly when considering the conversion rate to sternotomy [15]. Despite the significant learning curve and increased operative times associated with MIDCAB, the associated cost–benefit analysis, minimally invasive approach, shorter hospital stay, and avoidance of cardiopulmonary bypass support the continued application and long-term study of MIDCAB. Ultimately, decisions regarding hybrid revascularization, MIDCAB, and traditional CABG should be patient-centered and aim to offer improved benefits without completely replacing traditional sternotomy.

Robotic valvular procedures require peripheral cannulation for cardiopulmonary bypass, typically via the femoral, axillary, or jugular vessels. These procedures are performed via a right transaxillary thoracotomy incision, with additional thoracoscopic ports placed bilaterally.

Femoral cannulation during robotic procedures carries a risk of lower-extremity ischemia, and further studies are needed to identify complications specific to the robotic approach. Concomitant robotic procedures have been described with valve surgery, and additional research is warranted in higher-risk patients with prior sternotomy and mediastinal adhesions.

Further studies are also needed to assess outcomes in higher-risk populations, as robotic aortic valve replacement may represent a viable alternative to transcatheter therapies in select high-risk patients. With broader adoption of the robotic approach, operative times may decrease while still offering shorter lengths of stay and reduced postoperative pain compared with conventional sternotomy.

Surgeons should continue to remain proficient in the traditional sternotomy approach while also preparing to adopt robotic minimally invasive approaches for valvular surgery. Robotic valvular procedures have a significant learning curve and should be undertaken only after gaining adequate experience with sternotomy approaches. Furthermore, valvular calcification can preclude adequate repair via robotic assistance; if debridement is required, sternotomy is necessary [29]. As with robotic coronary artery bypass approaches, the higher operative costs can be offset by shorter lengths of stay; however, successful implementation usually requires a high-volume center to optimize efficiency and operative times for robotic valve procedures.

Transcatheter aortic valve implantation (TAVI) continues to evolve, with ongoing improvements in bioprosthetic design that have facilitated the use of this approach in intermediate- and low-risk surgical patients. TAVI implant modifications have included external cuffs for improved intra-annular seating and anti-calcification treatments. Current TAVI options include balloon-expandable and self-expandable devices, some of which are repositionable or retrievable [30].

The MitraClip system, a form of transcatheter edge-to-edge repair (TEER), received approval from the United States Food and Drug Administration (FDA) for primary mitral regurgitation in 2013 and for secondary mitral regurgitation in 2019. The PASCAL transcatheter device, currently under investigation, uses two clasps and paddles to grasp the mitral leaflets, while a central spacer reduces regurgitation. All transcatheter edge-to-edge repair techniques require specific anatomic criteria to achieve optimal outcomes. Transcatheter mitral valve replacement (TMVR) offers an alternative for high-risk surgical patients who are not candidates for TEER and is deployed via a transapical or transseptal approach. Transcatheter mitral annuloplasty represents another addition to the armamentarium of transcatheter devices.

TEER for the tricuspid valve (T-TEER) has been studied in patients with symptomatic tricuspid regurgitation who are high-risk for cardiac surgery [31]. For patients with large tricuspid annuli, excessive coaptation gaps, complex anatomy, or advanced disease, transcatheter tricuspid valve replacement (TTVR) represents another promising alternative option.

Transcatheter therapies were initially introduced for patients considered high-risk surgical candidates, but have the potential to be applied to an expanded population. The use of these devices requires that patients meet anatomical and physiologic criteria, while long-term outcome data remain limited in lower-risk and younger patients, who may have concerns about potential complications arising decades later. Transcatheter therapy avoids the need for cardiopulmonary bypass and sternotomy, thereby reducing hospital length of stay and postoperative complications.

Transcatheter therapies are best offered through shared decision-making between patients and the multidisciplinary heart team. These procedures may be performed by either interventional cardiologists or surgeons, with each specialty providing valuable insight regarding the optimal procedural approach for a specific patient. These discussions should also include long-term planning for potential redo transcatheter or surgical procedures following transcatheter therapy, as well as concomitant procedures. Surgeons need to be on standby in case of a failure during device deployment.

Open sternotomy atrial ablation, known as the MAZE procedure, has long been considered the gold standard therapy for persistent atrial fibrillation. However, owing to the invasive nature of open sternotomy atrial ablation, patients who are not undergoing other cardiac surgical procedures commonly elect for catheter-based endocardial ablation. Recent innovations have included complete thoracoscopic ablation and hybrid ablation combining the thoracoscopic and catheter-based approaches.

Catheter ablation is typically not durable, with a reported success rate as low as 28% at 5 years, compared with 97% for surgery in patients with persistent atrial fibrillation [51]. The hybrid approach involves creating thoracoscopic epicardial lesions followed by catheter-based endocardial lesions. This strategy has demonstrated superior 16-month freedom from recurrence of persistent atrial fibrillation compared with a catheter-based approach without antiarrhythmic drugs (86.7% versus 53.3%) [52]. Performing complete thoracoscopic MAZE lesions was reported to be non-inferior to open sternotomy, with shorter ICU length of stay, lower operative mortality, and shorter hospital stay [53]. Almousa et al. [54] reported that complete biatrial lesion creation via a robotic approach achieved freedom from recurrence of persistent atrial fibrillation greater than 90% at 1 year off antiarrhythmic drugs; however, longer follow-up is needed.

With further development and practice of minimally invasive lesion-based approaches for atrial fibrillation, patients may be more amenable to surgical approaches, allowing for more sustained freedom from recurrent atrial fibrillation without antiarrhythmic medications. However, long-term evidence for minimally invasive surgical approaches remains limited, which prevents their widespread adoption. Additionally, patients may also be hesitant to pursue surgical ablation while catheter-based ablation is available. Nevertheless, the hybrid approach may enable more effective treatment of atrial fibrillation in patients who would otherwise choose catheter-only based ablation. Although hybrid approaches and total thoracoscopic MAZE may approach the short-term outcomes of traditional sternotomy MAZE, long-term analysis is necessary to evaluate non-inferiority.

Hybrid thoracoscopic and catheter-based approaches, as well as complete thoracoscopic approaches, have a substantial learning curve and are therefore limited to high-volume centers with adequate infrastructure and surgical experience. Successful implementation of the hybrid approach requires a heart team to manage atrial fibrillation, with collaboration among cardiac electrophysiologists, surgeons, and cardiologists for therapeutic planning and appropriate selection of surgical candidates.

The Impella has been used as a temporary ventricular assist device. This microaxial pump is placed in the left ventricle, thereby improving cardiac output, increasing coronary perfusion, and decreasing ventricular load. Use of the Impella has increased in the United States, as evidenced by the rising application of this device among patients with Medicare being managed for acute myocardial infarction or cardiogenic shock [55]. The Impella CP can deliver up to 4 L/min of flow and, similar to the Impella 2.5, can be inserted percutaneously. The Impella 5.5 can provide up to 5.0 L/min of flow and requires surgical insertion via the femoral or axillary arteries. The Impella RP Flex provides temporary mechanical circulatory support for right ventricular failure refractory to medical management and may be used as a bridge to recovery or to additional surgical procedures.

The first generation of LVADs provided pulsatile flow and included the HeartMate Extended Vented Electric and Novacor N100 [56]. The HeartMate II and Jarvik 2000 LVADs comprised the second generation of devices providing continuous flow via axial-flow pumps with fewer mechanical components. These devices are smaller and less susceptible to mechanical wear; however, continuous flow is associated with a higher risk of bleeding, attributed to degradation of von Willebrand factor (vWF) multimers. The HeartMate II can be implanted via a thoracoabdominal approach without a percutaneous ventilator, and the Jarvik 2000 axial-flow rotor is implanted into the left ventricle via a left lateral thoracotomy. Third-generation LVADs provide centrifugal flow and use magnetically levitated rotating components (MAGLEV technology) to minimize wear, thrombosis, and hemolysis [56]. The additional sensory and suspensory components require more energy [57]. The HeartMate III incorporates centrifugal flow, while the HeartWare device additionally includes hydrodynamic support, allowing blood flow to provide suspension between components [58].

In a propensity-adjusted analysis of 2156 patients from the Premier Healthcare database, the Impella reduced the risk of myocardial infarction by 71% and cardiogenic shock by 46% when used pre-emptively in patients undergoing high-risk PCI. The reduction in cardiogenic shock was associated most strongly with mortality [59]. Iannaccone et al. [60] reported improved survival among patients receiving the Impella CP for cardiogenic shock; however, the IMPRESS trial showed no significant difference in 30-day or 6-month mortality between Impella CP and IABP [61]. The DANGER trial compared routine Impella CP insertion for cardiogenic shock secondary to myocardial infarction to the standard of care and found significantly lower 180-day mortality with Impella CP (45.8% versus 58.5%) [62].

Outcomes following Impella placement vary significantly, reflecting the diverse applications of this device, including pre-emptive insertion during cardiac procedures and emergent restoration of flow during circulatory collapse. Maigrot et al. [63] reported that patients who received an Impella 5.5 in earlier stages of cardiogenic shock were more likely to be successfully transitioned to permanent circulatory support or heart transplantation than patients with impending circulatory collapse. Further study is warranted regarding the use of Impella 5.5 in high-risk patients undergoing cardiac procedures, particularly in anticipation of decompensation to cardiogenic shock. Eisenga et al. [64] reported in a cohort of 10 patients undergoing high-risk cardiac surgery (median EF 25%) that perioperative use of the Impella 5.5 was associated with a 90% hospital discharge rate and an 80% 30-day survival. Benke et al. [65] reported a 30-day survival of nearly 93% in 14 patients who received Impella 5.0/5.5 support before high-risk CABG.

The RECOVER RIGHT study was a prospective study of 30 patients receiving the Impella RP Flex, 18 of whom developed right ventricular failure after LVAD implantation [66]. Hemodynamic benefits included a statistically significant improvement in cardiac index and a decrease in central venous pressure, with a 30-day survival of 73.3%. In a retrospective study of 22 patients, 15 of whom received left ventricular support, overall survival was 68%, accompanied by a reduction in mean lactate levels post-insertion [67]. Larger clinical studies are needed to develop guidelines that establish criteria and indications for the use of the Impella RP Flex.

Slaughter et al. [68] compared outcomes in patients receiving the HeartMate II versus those receiving the HeartMate I and found significantly higher 2-year survival free from disabling stroke or reoperation to repair or replace the LVAD with the HeartMate II (46% versus 11%). The 2-year mortality rate was also significantly lower with the HeartMate II (33% versus 41%). The MOMENTUM 3 study is a randomized controlled trial comparing outcomes in patients receiving either the HeartMate III or HeartMate II LVAD [69]. Per protocol analysis, the HeartMate III was associated with significantly lower rates of pump thrombosis (1.4% versus 13.9%), stroke (9.9% versus 19.4%), and bleeding (43.7% versus 55.0%) [70]. In a retrospective observational study, no significant differences in mortality or major adverse cardiovascular events were observed between the HeartMate III and HeartWare; however, the HeartWare was associated with a significantly higher malfunction rate of 20%.

tMCS provides patients with a bridge to LT-MCS, which can be used either as destination therapy or a bridge to transplant. Evidence strongly suggests improved survival with the Impella CP in cardiogenic shock, and recently established guidelines for Impella insertion will enable more standardized implementation. A small but significant percentage of patients are candidates for weaning from mechanical circulatory support. In patients with ventricular failure refractory to intensive medical management, mechanical circulatory support devices provide an additional measure to prolong survival and allow for either heart transplant or recovery of cardiac function.

Guidelines for LT-MCS implantation are available but not definitive, and require consideration of anticipated recovery, comorbidities, and the social context of patients. Furthermore, cardiologists and cardiac surgeons must be familiar with the management and surgical implantation of multiple devices, which entails a substantial learning curve in a continually evolving landscape of device therapies. Current efforts to improve LVAD therapy include reducing device size and the number of components, particularly the subcutaneous lines, which are prone to infection. A miniature ventricular assist device has been studied in an ovine preclinical model and has the potential benefit of applicability in smaller patients. Moreover, this device provides a comparable flow rate of up to 7 L/min with acceptable hemocompatibility and biocompatibility [71]. Future improvements may include implementing transcutaneous energy to avoid the need for a subcutaneous line. Although the device has been previously tested, reports of device failure and electromagnetic interference with transcutaneous energy transfer indicate that further improvement is necessary [56].

SynCardia/CardioWest were the first devices to be approved for bridge-to-transplantation in patients with biventricular failure, using diaphragm-pneumatically driven pumps [72]. The Carmat TAH, approved in 2020, uses bioprosthetic material and biological valves that come into contact with blood to reduce the risk of thrombosis and is currently being evaluated in human trials. The ReinHeart device is being developed with a transcutaneous battery-charging system, thereby avoiding the potential for power-line infection. One drawback of these devices is the associated large size, which restricts use in patients with small thoracic cavities, particularly women. To address this, the BiVACOR is being developed with a displaceable, rotary magnetic propulsion system that enables implantation of a smaller device in smaller patients [72]. Similarly, the Cleveland Clinic Continuous-Flow TAH is a valveless, pulsatile model under development that aims to increase applicability for smaller patients while avoiding the need for a percutaneous pneumatic cable through the use of a rotary propulsion system [73].

Although robotics has not been as widely adopted in the surgical management of heart failure as in other cardiac procedures, reports have illustrated its potential. Khalpey et al. [74] described a robotic approach to LVAD implantation via bilateral mini-thoracotomy, which was associated with a reduced length of stay. Khaliel et al. [75] describe the first robotic orthotopic heart transplant in a 16-year-old boy, and in the United States, a Baylor robotic heart transplant was performed successfully in an adult [76].

Xenotransplantation remains predominantly in the preclinical stage. Reports of genetically modified porcine hearts implanted into human recipients highlight the feasibility of xenotransplantation; however, the rejection of donor specimens despite porcine donor genetic modification and aggressive immunosuppression shows that further investigation into immunogenic targets is necessary [77].

A partial heart transplant was first performed in 2022 in a 17-day-old patient with truncus arteriosus. Subsequent procedures included partial heart transplants involving the mitral valve and right ventricular-to-pulmonary artery conduit [78].

Currently, Syncardia is the only FDA-approved TAH. In a 20-year retrospective study of 196 patients in Germany, Razumov et al. [79] found 1-month, 6-month, and 1-year mortality rates of 28%, 56%, and 61%, respectively. Overall, 35.2% of patients survived to transplantation, with a median post-transplant survival time of 5.8 years. TAHs are typically indicated for patients with severe biventricular failure or for those with contraindications to bilateral ventricular assist device implantation. In a retrospective study, 90-day post-transplant mortality was significantly higher among patients with TAH compared with those with LVAD or undergoing de novo transplants (12.2% versus 6.4% versus 5.4%, respectively); however, patients with TAH before transplant had higher rates of renal dysfunction, dialysis, and functional limitation [80]. Ferrall et al. [81] found similar post-transplant survival between State as biventricular assist device (BiVAD) and TAH recipients at high-volume centers. In a prospective single-institution study of 100 patients, TAH support was associated with a 1-year mortality of 34%, a transplantation rate of 46%, and a 95.1% survival at 6 months post-transplant [82].

The TAH is a practical alternative to BiVAD because this option enables synchronized operation of the associated components and avoids the need for reoperation to place a right-sided ventricular assist device (VAD) when indicated. However, device availability and experience with TAH remain limited, and this option applies only to patients with thoracic cavities large enough to accommodate a TAH. Xenotransplantation requires continued research into immunogenic targets and immunosuppression regimens before successful long-term application in humans. Benefits of partial heart transplant include the availability of donor hearts that are not otherwise suitable for orthotopic heart transplant and the potential for reduced doses of immunosuppressive therapy; however, further clinical application and research are needed to evaluate outcomes and optimize immunosuppression. Nevertheless, partial heart transplants have the potential for successful outcomes, as cases have shown the growth capacity of transplanted tissue in pediatric recipients [78].

Ferrall et al. [81] reported a higher incidence of multiple organ dysfunction and dialysis in patients with TAH, as well as a higher post-transplant survival in patients with previous BiVAD compared with those with TAH, even when comparing single-organ transplant recipients. These findings suggest that dialysis is not the only factor affecting post-transplant outcomes and that TAH may be better suited for patients with multiple organ dysfunction [81]. The choice between BiVAD and TAH depends on center volume and device availability, in addition to the clinical history unique to each patient. Further development is needed to ensure long-term device functionality and applicability to a wider range of patients, particularly those with smaller thoracic cavities. Partial heart transplantation has the potential to increase the availability of donor tissue, as recipients can have their own tissue donated, and donor hearts can be used to supply tissue to multiple recipients. Ethical considerations include whether orthotopic transplants should take precedence over a partial heart transplant for a specific patient [78].