Robotic CABG and Hybrid Approaches: The Current Landscape

Review of Contemporary Techniques for Minimally Invasive Coronary Revascularization

Minimally invasive coronary revascularization techniques aim to avoid median sternotomy with its associated complications, while facilitating recovery and maintaining the benefits of surgical revascularization. The 3 most common procedures are minimally invasive coronary artery bypass grafting, totally endoscopic coronary artery bypass, and hybrid coronary revascularization. For a variety of reasons, including cost and technical difficulty, not many centers are routinely performing minimally invasive coronary revascularization. Nevertheless, many studies have assessed the safety and efficacy of each of these procedures in different clinical contexts. Thus far results have been promising, and with the evolution of procedural techniques, these approaches have the potential to redefine coronary revascularization in the future. This review highlights the current state of minimally invasive coronary revascularization techniques by exploring their benefits, identifying barriers to their adoption, and discussing future potential paradigms.

Hybrid coronary revascularization: are we there yet?

PURPOSE OF REVIEW

With advances in minimally invasive surgical and percutaneous coronary therapies, hybrid coronary revascularization (HCR) is well positioned to be an ideal strategy for revascularization in selected patients with multivessel coronary artery disease (CAD). The purpose of this review is to highlight recent outcomes and comparative effectiveness studies of HCR.

RECENT FINDINGS

Patients undergoing HCR have comparable outcomes compared with coronary artery bypass grafting (CABG) and percutaneous coronary intervention (PCI). The major benefits compared with CABG appear to be related to short-term morbidity and resource utilization. Compared with PCI, HCR may decrease repeat revascularization rates by decreasing reintervention of the left anterior descending coronary artery.

SUMMARY

Although HCR is associated with a significant learning curve, specifically with minimally invasive CABG techniques, the early outcomes remain promising and should be considered as a viable option for revascularization in select patients with multivessel CAD.

Robotic Cardiac Surgery Part II: Anesthetic Considerations for Robotic Coronary Artery Bypass Grafting

Coronary artery bypass grafting represents one of the most commonly performed cardiac surgeries worldwide. Recently, interest has increased in providing patients with a less invasive approach to cardiac surgery, such as thoracotomy and endoscopic techniques using robotic technology as an alternative to traditional sternotomy. As the population gets older, the need for additional methods to provide care for sick patients will continue to expand. These advancements will further allow physicians to provide cardiac surgical procedures with less pain and faster recovery for patients.

Factors causing prolonged mechanical ventilation and peri-operative morbidity after robot-assisted coronary artery bypass graft surgery

Robot-assisted coronary artery bypass graft [robot-assisted (coronary artery bypass grafting (CABG)] surgery is the latest treatment for coronary artery disease. However, the surgery extensively affects cardiac and pulmonary function, and the risk factors associated with peri-operative morbidity, including prolong mechanical ventilation (PMV), have not been fully examined. In this retrospective cohort study, a total of 382 patients who underwent robot-assisted internal mammary artery harvesting with mini-thoracotomy direct-vision bypass grafting surgery (MIDCABG) from 2005 to 2012 at our tertiary care hospital were included. The definition of PMV was failure to wean from mechanical ventilation more than 48 h after the surgery. Risk factors for PMV, and peri-operative morbidity and mortality were analyzed with a multivariate logistic regression model. Forty-three patients (11.3%) developed PMV after the surgery, and the peri-operative morbidity and mortality rates were 38 and 2.6%, respectively. The risk factors for PMV were age, left ventricular ejection fraction (LVEF), the duration of one-lung ventilation for MIDCABG (beating time), and peak airway pressure at the end of the surgery. Furthermore, age and anesthesia time were found to be independent risk factors for peri-operative morbidity, whereas age, LVEF, and anesthesia time were the risk factors for peri-operative mortality. These findings may help physicians to properly choose patients for this procedure, and provide more attention to patients with higher risk after surgery to achieve better clinical outcomes.

Hybrid Revascularization: A Review

Hybrid coronary revascularization (HCR) combines surgical bypass with percutaneous coronary intervention (PCI) performed either during the same procedure or in a staged approach within 60 days. Coronary artery bypass grafting using the left internal mammary artery (LIMA) has shown excellent long-term patency with improved patient survival. It remains the gold standard treatment for the majority of patients with multivessel coronary artery disease. However, saphenous vein grafts have poor long-term patency. Advances in stent technology have resulted in reduced rates of thrombosis and restenosis, making PCI a viable alternative to coronary surgery in selected patients. HCR is attractive as a less invasive method of coronary revascularization which preserves the benefits of the LIMA performed with less invasive surgical techniques with the efficacy of newer generation stents.

Short-Term and Mid-Term Clinical Outcomes Following Hybrid Coronary Revascularization Versus Off-Pump Coronary Artery Bypass: A Meta-Analysis

BACKGROUND

Off-pump coronary artery bypass grafting (OPCAB) is one of the standard treatments for coronary artery disease (CAD) while hybrid coronary revascularization (HCR) represents an evolving revascularization strategy. However, the difference in outcomes between them remains unclear.

OBJECTIVE

We performed a meta-analysis to compare the short-term and mid-term outcomes of HCR versus OPCAB for the treatment of multivessel or left main CAD.

METHODS

We searched the PubMed, EMBASE, Web of Science and Cochrane databases to identify related studies and a routine meta-analysis was conducted.

RESULTS

Nine studies with 6121 patients were included in the analysis. There was no significant difference in short-term major adverse cardiac and cerebrovascular event (MACCE) rate (RR: 0.55, 95% CI: 0.30-1.03, p = 0.06) or mortality (RR: 0.51, 95% CI: 0.17-1.48, p = 0.22). HCR required less ventilator time (SMD: -0.36, 95% CI: -0.55- -0.16, p < 0.001), ICU stay (SMD: -0.35, 95% CI: -0.58 - -0.13, p < 0.01), hospital stay (SMD: -0.29, 95% CI: -0.50- -0.07, p < 0.05) and blood transfusion rate (RR: 0.57, 95% CI: 0.49-0.67, p < 0.001), but needed more operation time (SMD: 1.29, 95% CI: 0.54-2.05, p < 0.001) and hospitalization costs (SMD: 1.06, 95% CI: 0.45-1.66, p < 0.001). The HCR group had lower mid-term MACCE rate (RR: 0.49, 95% CI: 0.26-0.92, p < 0.05) but higher rate in mid-term target vessel revascularization (TVR, RR: 2.20, 95% CI: 1.32-3.67, p < 0.01).

CONCLUSIONS

HCR had similar short-term mortality and morbidity comparing to OPCAB. HCR decreased the ventilator time, ICU stay, hospital stay, blood transfusion rate and increased operation time and hospitalization costs. HCR has a lower mid-term MACCE rate while OPCAB shows better in mid-term TVR.

Intracoronary delivery of recombinant TIMP-3 after myocardial infarction: effects on myocardial remodeling and function

Ischemia-reperfusion (IR) and myocardial infarction (MI) cause adverse left ventricular (LV) remodeling and heart failure and are facilitated by an imbalance in matrix metalloproteinase (MMP) activation and the endogenous tissue inhibitors of metalloproteinase (TIMPs). We have identified that myocardial injections of recombinant TIMP-3 (rTIMP-3; human full length) can interrupt post-MI remodeling. However, whether and to what degree intracoronary delivery of rTIMP-3 post-IR is feasible and effective remained to be established. Pigs (25 kg) underwent coronary catheterization and balloon occlusion of the left anterior descending coronary artery (LAD) for 90 min whereby at the final 4 min, rTIMP-3 (30 mg, n = 9) or saline was infused in the distal LAD. LV echocardiography was performed at 3-28 days post-IR, and LV ejection fraction (EF) and LV end-diastolic volume were measured. LV EF fell and LV end-diastolic volume increased from baseline (pre-IR) values (66 ± 1% and 40 ± 1 ml, respectively, means ± standard deviation) in both groups; however, the extent of LV dilation was reduced in the rTIMP-3 group by 40% at 28 days post-IR (P < 0.05) and the fall in LV EF was attenuated. Despite equivalent plasma troponin levels (14 ± 3 ng/ml), computed MI size at 28 days was reduced by over 45% in the rTIMP-3 group (P < 0.05), indicating that rTIMP-3 treatment abrogated MI expansion post-IR. Plasma NH2-terminal pro-brain natriuretic peptide levels, an index of heart failure progression, were reduced by 25% in the rTIMP-3 group compared with MI saline values (P < 0.05). Although the imbalance between MMPs and TIMPs has been recognized as a contributory factor for post-MI remodeling, therapeutic strategies targeting this imbalance have not been forthcoming. This study is the first to demonstrate that a relevant delivery approach (intracoronary) using rTIMP can alter the course of post-MI remodeling.NEW & NOTEWORTHY Myocardial ischemia and reperfusion injury remain significant causes of morbidity and mortality whereby alterations in the balance between matrix metalloproteinase and tissue inhibitor of metalloproteinase have been identified as contributory biological mechanisms. This novel translational study advances the concept of targeted delivery of recombinant proteins to modify adverse myocardial remodeling in ischemia-reperfusion injury.

Coronary Atherosclerosis: Pathophysiologic Basis for Diagnosis and Management

Coronary atherosclerosis is a long lasting and continuously evolving disease with multiple clinical manifestations ranging from asymptomatic to stable angina, acute coronary syndrome (ACS), heart failure (HF) and sudden cardiac death (SCD). Genetic and environmental factors contribute to the development and progression of coronary atherosclerosis. In this review, current knowledge related to the diagnosis and management of coronary atherosclerosis based on pathophysiologic mechanisms will be discussed. In addition to providing state-of-the-art concepts related to coronary atherosclerosis, special consideration will be given on how to apply data from epidemiologic studies and randomized clinical trials to the individual patient. The greatest challenge for the clinician in the twenty-first century is not in absorbing the fast accumulating new knowledge, but rather in applying this knowledge to the individual patient.