The Use of Intraoperative Transit Time Flow Measurement for Coronary Artery Bypass Surgery: Systematic Review of the Evidence and Expert Opinion Statements

Intraoperative Transit-Time Flow as a Predictor of Failure after Infrainguinal Revascularization with Heparin-Bonded Expanded Polytetrafluoroethylene Graft

BACKGROUND

The heparin-bonded expanded polytetrafluoroethylene (He-ePTFE) conduit is an option for patients requiring infrainguinal revascularization (iIR), but the risk of failure may be unpredictable, especially in cases with poor run-off. Intraoperative transit-time flow (TTF) provides an automated and quantitative analysis of flow and may serve as an adjunct evaluation during surgical revascularization. The aim of this study was to assess TTF in patients undergoing iIR with He-PTFE at 3 referral hospitals and to establish a predictive flow threshold for graft occlusion.

METHODS

A prospective registry initiated in 2020 enrolled patients undergoing iIR using He-PTFE for critical limb ischemia or severe claudication, and TTF measurement was analyzed. Preoperative assessments of anatomical and clinical characteristics were available for all patients. The HT353 Optima Meter (Transonic Systems Inc., Ithaca, NY, USA) was used in all procedures according to a standardized protocol. The institutional ethics committee approved the study. A predictive model using receiver operating characteristic curve analysis was utilized to establish the threshold of flow, and variables were compared. Anatomical and clinical evaluation were reported according to Rutherford grade, Global Limb Anatomic System and Wound, Ischemia, and foot Infection classification. The main outcome considered was the correlation between TTF and graft occlusion. Secondary outcomes included survival, other predictors of graft occlusion, freedom from major adverse cardiovascular events, and freedom from major amputation.

RESULTS

Among 68 patients, 55.8% had Rutherford 5-6, 45.6% had Global Limb Anatomic System 3 and 73.5% had Wound, Ischemia, and foot Infection 3-4. Distal anastomosis was at tibial level in 23.5% and mean diameter of conduit was 6.4 mm. Basal and postoperative TTF were 27.8 ± 15.6 ml/min and 109.0 ± 53.0 ml/min, respectively. After a mean follow-up of 18 ± 13 months, 7 (10.9%) patients presented graft occlusion and 5 (7.8%) required major amputation. TTF threshold = 80 ml/min revealed a sensitivity and specificity of 81.8% (95% confidence interval 48.2-97.7) and 80.7% (95% confidence interval 68.1-90.0) respectively, and it was selected as cut-off for graft occlusion. Freedom from graft occlusion in patients with TTF >80 ml/min vs. TTF ≤80 ml/min at 6, 12, and 24 months was 95.7% (standard error (SE) = 0.030) vs. 65.5% (SE = 0.115), 95.7% (SE = 0.030) vs. 58.9% (SE = 0.120) and 90.9% (SE = 0.054) vs. 51.6% (SE = 0.126), P = 0.0003. No statistical difference in primary patency, secondary patency and limb salvage was observed. At multivariate analysis, distal anastomosis at tibial vessel (odds ratio 8.50) and TTF ≤80 ml/min (odds ratio 9.39) were independent predictors of graft occlusion.

CONCLUSIONS

These results suggest that TTF may serve as a valuable tool in the management of iIR. A TTF measurement of ≤80 ml/min should be regarded as a predictor of graft occlusion, prompting consideration of additional intraoperative maneuvers to enhance arterial flow. Caution should be exercised in patients requiring direct tibial artery revascularization, as it represents a predictor of failure independent of TTF levels. Larger cohorts of patients and longer follow-up periods are necessary to confirm these findings.

Intraoperative Prediction of Coronary Graft Failure Based on Transit Time Flow Measurement: A PRELIMINARY STUDY

Myocardial revascularization has been known to not affect the prognosis in some patients. Coronary artery bypass graft (CABG) failure may develop one year after CABG surgery. This is accompanied by a high risk of developing myocardial infarction after complete myocardial revascularization in obstructive coronary artery disease (CAD) due to microvascular dysfunction. The study of microvascular dysfunction using intraoperative stress tests with adenosine triphosphate (ATP) allows for the assessment of the coronary bypass flow reserve (CBFR) and the risk of graft failure one year after surgery. The study included 79 CAD patients (238 grafts) who underwent dynamic single-photon emission computed tomography (SPECT) before CABG and dynamic transit time flow measurement (TTFM) during CABG at rest and at stress. The CBFR was calculated by the ratio of the mean graft flow (MGF) at stress to the MGF at rest. A multivariate regression model showed that the MGF at rest (p = 0.043), the MGF at stress (p = 0.026) and the CBFR (p = 0.0001) were significant independent predictors of graft failure. As a result of ROC analysis, the threshold CBFR < 1.67 units correlated with graft failure more closely (sensitivity 82%, specificity 90%) The CBFR is a significant independent predictor of graft failure for up to 16 months.

Mid-term outcomes of endoscopic vein harvesting in coronary artery bypass grafting: a retrospective cohort study

OBJECTIVES

Endoscopic vein harvesting (EVH) is an alternative technique to obtain the saphenous vein for coronary artery bypass grafting (CABG) surgery. We aimed to evaluate the early and mid-term outcomes of patients with EVH in CABG.

METHODS

This cohort study included consecutive isolated CABG patients in Nanjing First Hospital from July 2020 to December 2022 using propensity score matching methods. Patients were classified to EVH group and open vein harvesting (OVH) group according to the vein harvesting methods. The primary outcome was the all-cause death, and the secondary outcomes were major adverse cardiovascular events (MACEs) including cardiovascular death, heart failure, myocardial infarction and revascularization and asymptomatic survival in the follow-up.

RESULTS

Totally 1247 patients were included in the study with 849 in OVH group and 398 in EVH group. Patients with EVH were more female, diabetes, higher body mass index, more multi-vessel and left main diseases. 308 pairs were formed after the matching. There was no significant difference in the rates of in-hospital death (EVH vs. OVH, 2.3% vs. 1.3%, P = 0.543). During the 3 years follow-up, EVH grafts were considered not inferior to OVH grafts, no differences were found in all-cause death [8.5% vs. 5.0%, hazard ratio (HR) 1.565, 95% confidence interval (CI): 0.77-3.17, P = 0.21], MACEs (8.1% vs. 7.1%, HR 1.165, 95CI: 0.51-2.69, P = 0.71) and asymptomatic survival (66.7% vs. 72.5%, HR 1.117, 95%CI: 0.65-1.92, P = 0.68).

CONCLUSIONS

EVH grafts were considered comparable to OVH grafts in patients following CABG in the 3 years follow-up.

Performance of left internal thoracic artery-left anterior descending artery anastomosis by residents versus attendings and coronary artery bypass grafting outcomes

OBJECTIVES

Performance of a technically sound left internal thoracic artery to left anterior descending artery (LITA-LAD) anastomosis during coronary artery bypass grafting (CABG) is critically important. We used prospectively collected data from the multicentre, randomized REGROUP (Randomized Endograft Vein Perspective) trial to investigate CABG outcomes based on whether a resident or an attending surgeon performed the LITA-LAD anastomosis.

METHODS

This was a post hoc subanalysis of the REGROUP trial, which randomized veterans undergoing isolated on-pump CABG to endoscopic versus open vein harvest from 2014 through 2017. The primary end point was major cardiac adverse events, defined as the composite of all-cause deaths, nonfatal myocardial infarctions or repeat revascularizations.

RESULTS

Among 1,084 patients, 344 (31.8%) LITA-LAD anastomoses were performed by residents and 740 (68.2%), by attending surgeons. Residents (compared to attendings) operated on fewer patients with high tercile SYNTAX scores (22.1% vs 37.4%, P < 0.001), performed fewer multiarterial CABGs (5.2% vs 14.6%, P < 0.001) and performed more anastomoses to distal targets with diameters > 2.0 mm (19.0% vs 10.9%, P < 0.001) and non-calcified landing zones (25.1% vs 21.6%, P < 0.001). During a median observation time of 4.7 years (interquartile range 3.84-5.45), major cardiac adverse events occurred in 77 patients (22.4%) in the group treated by residents and 169 patients (22.8%) in the group treated by attendings (unadjusted HR 1.00; 95% confidence interval, 0.76-1.33; P = 0.99). Outcomes persisted on adjusted analyses.

CONCLUSIONS

Based on this REGROUP trial subanalysis, under careful supervision and with appropriate patient selection, LITA-LAD anastomoses performed by the residents yielded clinical outcomes similar to those of the attendings.

Transient time flow measurement in arterial grafts

Coronary artery bypass grafting (CABG) is one of the foundations of treatment for coronary artery disease. While it has improved substantially since its inception more than 50 years ago, including a rising use of multiple arterial grafting, intraoperative quality assessment is yet to be disseminated as an integral part of the procedure. Herein we review the fundamentals of intraoperative quality assessment in CABG using transient time flow measurement (TTFM) with a focus on its use in arterial grafting.

Less Invasive and Hybrid Surgical/Interventional Coronary Disease Management: The Future Is Now

Coronary artery bypass grafting (CABG) has evolved to become the criterion standard in elective revascularisation for coronary artery disease (CAD), particularly in patients with complex or multivessel CAD, left main involvement, diabetes mellitus, or left ventricular dysfunction. Despite the superiority of CABG in patients with the most advanced forms of CAD, a standard CABG operation, through a median sternotomy and with the use of cardiopulmonary bypass, carries well recognised challenges. In this article, we describe newer approaches, such as off-pump CABG, minimally invasive bypass grafting, robotic CABG, and hybrid coronary revascularisation, which we consider as necessary ways to minimise invasion, reduce recovery time, provide the benefits of arterial grafting to more patients, and offer alternatives to mitigate the adverse effects of conventional sternotomy and cardiopulmonary bypass.

Identification of a Dissection Site in the Internal Thoracic Artery Using Fluorescence Imaging: A Case Report

A 66-year-old man with a history of type 2 diabetes mellitus who was undergoing hemodialysis presented with angina. Coronary angiography revealed triple-vessel coronary artery disease. He underwent multiple percutaneous coronary interventions due to recurrent restenosis and was referred for coronary artery bypass grafting (CABG). The left internal thoracic artery and bilateral saphenous veins were harvested under general anesthesia. Four CABGs were performed: left internal thoracic artery to the left anterior descending artery; saphenous vein graft to the obtuse marginal branch of the circumflex artery; and saphenous vein graft to two sites in the right coronary artery. Intraoperative assessment with transit-time flow measurements showed no abnormalities, and the surgery was completed. On postoperative day seven, coronary and graft angiography revealed dissection of the left internal thoracic artery at its midportion with restricted flow. On postoperative day eight, a surgical intervention was performed to excise the dissected segment of the left internal thoracic artery. The dissection site was identified by fluorescence imaging. The dissected segment was excised, and the artery was re-anastomosed. The postoperative course was uneventful, and graft angiography performed on postoperative day 22 confirmed good blood flow. Fluorescence imaging was valuable in identifying the dissection site in the left internal thoracic artery.

Coronary Artery Bypass Surgery: Evidence-Based Practice

Coronary artery bypass graft (CABG) surgery remains a pivotal cornerstone, offering established symptomatic alleviation and prognostic advantages for patients grappling with complex multivessel and left main coronary artery diseases. Despite the lucid guidance laid out by contemporary guidelines regarding the choice between CABG and percutaneous coronary intervention (PCI), a notable hesitation persists among certain patients, characterized by psychological reservations, knowledge gaps, or individual beliefs that sway their inclination toward surgical intervention. This comprehensive review critically synthesizes the prevailing guidelines, modern practices, and outcomes pertaining to CABG surgery, delving into an array of techniques and advancements poised to enhance both short-term and enduring surgical outcomes. The exploration encompasses advances in on-pump and off-pump procedures, conduit selection strategies encompassing the bilateral utilization of internal mammary artery and radial artery conduits, meticulous graft evaluation methodologies, and the panorama of minimally invasive approaches, including those assisted by robotic technology. Furthermore, the review navigates the terrain of hybrid coronary revascularization, shedding light on the pivotal roles of shared decision-making and the heart team in shaping treatment pathways. As a comprehensive compendium, this review not only navigates the intricate landscape of CABG surgery but also aligns it with contemporary practices, envisioning its trajectory within the evolving currents of healthcare dynamics.

Analysis of a multicenter registry on evaluation of transit-time flow in coronary artery disease surgery

Objective

The Evaluation of Transit-Time Flow in Coronary Artery Disease Surgery (EFCAD) registry aims to assess the influence of transit-time flow measurement (TTFM) in daily practice.

Methods

EFCAD is a prospective, multicenter study involving 9 centers performing TTFM during isolated coronary artery bypass grafting. Primary end point was occurrence and risk factors of major adverse cardiac events, including perioperative myocardial infarction, urgent postoperative coronary angiogram and/or revascularization, and hospital mortality. Secondary end points were rate of graft revision during surgery and factors affecting graft flow. We respected the limit values set by the experts: mean graft flow >15 mL/minute and pulsatility index ≤5.

Results

Between May 2017 and March 2021, 1616 patients were registered in the EFCAD database. After review, 1414 were included for analyses. Of those, 1176 were eligible for primary end point analysis. Graft revision, mainly due to inadequate TTFM values, occurred in 2% (29 patients). The primary end point occurred in 46 (3.9%) patients, and it was related with left anterior descending artery graft flow ≤15 mL/minute (odds ratio, 3.64; P < .001). Graft flow was related with number of grafts (3 vs 1-2, β = -1.6; 4-6 vs 1-2, β = -4.1; P < .001; β > 0 indicates higher flow), and graft origin (aorta vs Y, β = 9.2; in situ left internal thoracic artery vs Y, β = 3.2; in situ right internal thoracic artery vs Y, β = 2.3; P < .001).

Conclusions

Data from EFCAD study suggest that TTFM is reliable to evaluate graft flow, and acceptance of inadequate flow on left anterior descending artery anastomosis influence postoperative outcomes. In our opinion, TTFM assessment should be routinely used in coronary artery bypass procedures, even if interpretation depends on learning curves.

Designing the coronary artery bypass surgery operation of the future

PURPOSE OF REVIEW

This article discusses current shortcomings in coronary artery bypass surgery and ways to overcome them.

RECENT FINDINGS

Minimally invasive coronary bypass surgery, robotic coronary bypass, and hybrid approaches aim to avoid sternotomy, employ arterial grafts, and minimize the use of cardiopulmonary bypass. Other considerations such as bypass graft validation, the optimization of guideline-directed medical therapy, and the development of coronary surgery specialists are also crucial to further the benefits of coronary artery bypass grafting on future patients.

SUMMARY

Coronary artery bypass grafting must become less invasive, be better validated, and be carried out with an even higher emphasis on quality, including graft validation and preoperative/postoperative optimization, if it is to remain the best treatment for advanced, severe coronary artery disease.

Combining Minimally Invasive Direct Coronary Artery Bypass Grafting with Transapical Aortic Valve Implantation-The Next Level Heart Team Approach

We present the results of a combined approach for transapical aortic valve replacement and minimally invasive coronary artery bypass grafting (taTAVI-MIDCAB) in patients with combined aortic stenosis and coronary artery disease.

BACKGROUND

For patients presenting with aortic stenosis and coronary artery disease, a simultaneous procedure addressing both diseases is recommended to reduce operative risk. In high-risk patients with hostile femoral or coronary axis, taTAVI-MIDCAB can be an alternative minimally invasive approach, offering the benefits of left interior mammary artery to left anterior descending coronary artery (LIMA-LAD) grafting.

METHODS

From 2014 to 2022, 10 patients underwent taTAVI-MIDCAB for combined coronary and severe aortic stenosis in the hybrid operation theater at our institution. We assessed perioperative outcomes and follow-up outcomes.

RESULTS

The median age was 83 years (81 to 86). The procedure was successfully performed in all patients without conversion to sternotomy. The median length of hospital and intensive care unit stay was 9 days (7 to 16) and 2.5 days (1 to 5), respectively. The median flow over the coronary artery bypass was 31 (22 to 44) mL/min, with a pulsatility index (PI) of 2.4 (2.1 to 3.2). Mild paravalvular leak occurred in 2 patients (10%). There were no neurological events nor acute kidney injury. Pacemaker implantation was required in 1 patient (10%).

CONCLUSIONS

Simultaneous surgical coronary revascularization and interventional valve implantation in the setting of a hostile femoral and coronary axis appears to be safe and beneficial.

The Feasibility and Early Results of Multivessel Minimally Invasive Coronary Artery Bypass Grafting for All Comers

OBJECTIVES

Cardiovascular surgery advancements have emerged with various minimally invasive approaches for treating multivessel coronary disease to improve outcomes and minimize the burden associated with conventional cardiac surgery. We present our clinical experience and minimally invasive coronary bypass techniques through minithoracotomy, which we apply without selection to patients who have decided to have elective surgery for multivessel isolated coronary artery disease.

METHODS

It consists of 230 consecutive patients operated by the same team with this method between July 2020 and September 2022. The patients were assigned to one of the two methods preoperatively to their accompanying comorbidities and operated on either with blood cardioplegia via 5 to 7 cm left anterior minithoracotomy, with on-pump clamped technique or without pump via left anterolateral minithoracotomy.

RESULTS

Mortality was observed in two of our patients (0.9%), but myocardial infarction was not observed in our patients in the early postoperative period. None of our patients required conversion to sternotomy (0%). Five patients' needed reoperation from the same incision due to postoperative bleeding (2.2%), and atrial fibrillation developed in 17 patients in the postoperative period (7.4%). The mean number of bypasses was found to be 3.0 ± 0.9.

CONCLUSIONS

Minimally invasive coronary artery bypass surgery via minithoracotomy can be routinely reproduced safely. More long-term results and more multicenter studies are needed for more widespread acceptance of the technique.

Evaluating the Arteriotomy Size of a New Sutureless Coronary Anastomosis Using a Finite Volume Approach

OBJECTIVES

The ELANA® Heart Bypass creates a standardized sutureless anastomosis. Hereby, we investigate the influence of arteriotomy and graft size on coronary hemodynamics.

METHODS

A computational fluid dynamics (CFD) model was developed. Arteriotomy size (standard 1.43 mm2; varied 0.94 - 3.6 mm2) and graft diameter (standard 2.5 mm; varied 1.5 - 5.0 mm) were independent parameters. Outcome parameters were coronary pressure and flow, and fractional flow reserve (FFR).

RESULTS

The current size ELANA (arteriotomy 1.43 mm2) presented an estimated FFR 0.65 (39 mL/min). Enlarging arteriotomy increased FFR, coronary pressure, and flow. All reached a maximum once the arteriotomy (2.80 mm2) surpassed the coronary cross-sectional area (2.69 mm2, i.e. 1.85 mm diameter), presenting an estimated FFR 0.75 (46 mL/min). Increasing graft diameter was positively related to FFR, coronary pressure, and flow.

CONCLUSION

The ratio between the required minimal coronary diameter for application and the ELANA arteriotomy size effectuates a pressure drop that could be clinically relevant. Additional research and eventual lengthening of the anastomosis is advised.

Considerations on the Management of Acute Postoperative Ischemia After Cardiac Surgery: A Scientific Statement From the American Heart Association

Acute postoperative myocardial ischemia (PMI) after cardiac surgery is an infrequent event that can evolve rapidly and become a potentially life-threatening complication. Multiple factors are associated with acute PMI after cardiac surgery and may vary by the type of surgical procedure performed. Although the criteria defining nonprocedural myocardial ischemia are well established, there are no universally accepted criteria for the diagnosis of acute PMI. In addition, current evidence on the management of acute PMI after cardiac surgery is sparse and generally of low methodological quality. Once acute PMI is suspected, prompt diagnosis and treatment are imperative, and options range from conservative strategies to percutaneous coronary intervention and redo coronary artery bypass grafting. In this document, a multidisciplinary group including experts in cardiac surgery, cardiology, anesthesiology, and postoperative care summarizes the existing evidence on diagnosis and treatment of acute PMI and provides clinical guidance.

Defining the Role of Anaortic Coronary Artery Bypass Grafting

As the population ages and co-morbidities become more prevalent, the complexity of patients presenting for coronary artery bypass surgery is increasing. Cardiopulmonary bypass and aortic cross-clamping in these patients carry increased risk and, indeed, in some patients, with ascending aortic disease, the risks are prohibitive. Total-arterial anaortic coronary artery surgery is a technique that provides complete surgical coronary artery revascularization without cardiopulmonary bypass and without manipulating the ascending aorta. The technique essentially eliminates the risk of cerebral embolization of aortic atheroma and aortic injury. Anaortic techniques are an essential skillset for coronary artery surgery centers treating higher-risk patients.

Right-Sided Minimally Invasive Direct Coronary Artery Bypass: Clinical Experience and Perspectives

Objective: Minimally invasive direct coronary artery bypass grafting (MIDCAB) using the left internal thoracic artery to the left descending artery is a clinical routine in the treatment of coronary artery disease. Far less is known on right-sided MIDCAB (r-MIDCAB) using the right internal thoracic artery (RITA) to the right coronary artery (RCA). We aimed to present our experience in patients with complex coronary artery disease who underwent r-MIDCAB. Materials and Methods: Between October 2019 and January 2023, 11 patients received r-MIDCAB using RITA to RCA bypass in a minimally invasive technique via right anterior minithoracotomy without using a cardiopulmonary bypass. Underlying coronary disease was complex right coronary artery stenosis (n = 7) and anomalous right coronary artery (ARCA; n = 4). All procedure-related and outcome data were evaluated prospectively. Results: Successful minimally invasive revascularization was achieved in all patients (n = 11). There were no conversions to sternotomy and no re-explorations for bleeding. Furthermore, no myocardial infarction, no strokes, and, most importantly, no deaths were observed. During the follow-up period (median 24 months), all patients were alive and 90% were completely angina free. Two patients received a repeated revascularization after surgery but independently from the RITA-RCA bypass, which was fully competent in both patients. Conclusion: Right-sided MIDCAB can be performed safely and effectively in patients with expected technically challenging percutaneous coronary intervention of the RCA and in patients with ARCA. Mid-term results showed high freedom from angina in nearly all patients. Further studies with larger patient cohorts and more evidence are needed to provide the best revascularization strategy for patients suffering from isolated complex RCA stenosis and ARCA.

The use of intraoperative transit time flow measurement can reduce postoperative myocardial injury

OBJECTIVE

This study investigates the relationship between the use of transit time flow measurement (TTFM) and postoperative myocardial injury in off-pump coronary artery bypass grafting (OPCABG).

METHODS

In this retrospective study, we collected basic data from patients hospitalized for OPCABG in the Department of Cardiothoracic Surgery, Changzhou Second People's Hospital Affiliated with Nanjing Medical University. According to the academic research consortium (ARC)-2 definition of significant myocardial injury, we used cardiac troponin I >2380 ng/L as a criterion for significant postoperative myocardial injury. We use logistic regression and forest plots to assess the association of TTFM use with myocardial injury outcomes.

RESULTS

One hundred and forty-six patients were included in this study. The overall median age of these patients was 65.05 years, and 32 (21.92%) experienced a postoperative myocardial injury. TTFM was independently associated with the incidence of postoperative myocardial injury (odds ratio = 0.34 [95% confidence interval = 0.15-0.78]; p = .01), and we found similar trends in regression analyses across subgroups of sex, age, number of bridging vessels, hypertension, diabetes mellitus, BMI, and percutaneous coronary revascularization. One hundred and six patients were followed for 1-year vessel permeability, and seven patients (6.6%) were occluded.

CONCLUSIONS

The use of TTFM is independently associated with a reduced incidence of postoperative myocardial lesions during off-pump coronary bypass surgery. The TTFM procedure in OPCABG deserves to be actively promoted to reduce the incidence of postoperative myocardial injury.

Minimally invasive off-pump anaortic coronary artery bypass (MACAB)

BACKGROUND

Minimally invasive direct coronary artery bypass has enabled coronary artery bypass graft to compete with the appeal of less invasive percutaneous coronary procedures. Favorable results of coronary artery bypass surgery performed without the use of cardiopulmonary bypass and without touching the aorta (anOPCAB) have enabled the development and use of minimally invasive methods.

METHODS

Between 2016 and 2021, 112 patients underwent multivessel coronary bypass surgery performed using a minimally invasive method through a small thoracotomy in the left chest with off-pump, anaortic, and all-arterial grafts (Minimally Invasive Off-Pump Anaortic Coronary Artery Bypass [MACAB]). Patient data were collected and retrospectively analyzed. Eight series from the literature using the multivessel mini-OPCAB and MACAB technique were also evaluated.

RESULTS

Collectively, from the literature, 2729 patients underwent an average of 2.4 bypasses with an early mortality rate of 0.7% and a stroke rate of 0.16%. In our MACAB case series, 112 patients underwent an average of 2.9 bypasses with a mortality rate of 1.8% and a stroke rate of 0%.

CONCLUSION

MACAB can be performed safely by experienced surgeons and reduces neurological injury and surgical trauma and may be a good alternative for multivessel stenting. Simulation systems are essential for its dissemination, and teams dedicated to coronary surgery-with subspecialty expertise-are necessary to achieve good outcomes.

Left main coronary disease: evolving management concepts

Remarkable advances in the management of coronary artery disease have enhanced our approach to left main coronary artery (LMCA) disease. The traditional role of coronary artery bypass graft surgery has been challenged by the less invasive percutaneous coronary interventional approach. Additionally, major strides in optimal medical therapy now provide a rich menu of treatment choices in selected circumstances. Although a LMCA stenosis >70% is an acceptable threshold for revascularization, those patients with a LMCA narrowing between 40 and 69% present a more complex scenario. This review examines the relative merits of the different treatment options, addresses key diagnostic and therapeutic unknowns, and identifies future work likely to advance progress.

Transit time flow measurement guiding the surgical treatment for anomalous origin of the right coronary artery: A case report

Anomalous origin of a coronary artery from the opposite sinus of Valsalva (ACAOS) in symptomatic patients is a rare but serious finding whose treatment consists of a surgical correction. The surgical treatment has a level of complexity that could vary from unroofing and ostioplasty to coronary artery bypass grafting. We present our management of a 59-year-old woman presenting with chest pain and dyspnea for right ACAOS with an interarterial route. The right coronary artery (RCA) was bypassed with the right internal thoracic artery. An intraoperative transit time flowmetry (TTFM) showed a competitive flow from the native RCA. RCA proximal ligation site was identified intraoperatively, considering the best mean graft flow (MGF) and the absence of ischemic events. The patient was discharged after a week without adverse events. The 1-year follow-up was uneventful. The intraoperative use of TTFM could guide the surgeon's hand making straightforward the surgical treatment for ACAOS.

Randomized evidence on graft patency after off-pump versus on-pump coronary artery bypass grafting: An updated meta-analysis

BACKGROUND

The debate between off-pump CABG (OPCAB) and on-pump CABG (ONCAB) has been ongoing for decades. We aimed to provide a comprehensive update of the current randomized controlled trials (RCTs) in evaluating the graft patency of OPCAB versus ONCAB.

MATERIALS AND METHODS

A literature search was conducted in PubMed, EMBASE, and the Cochrane Library databases until April 30, 2021. All RCTs from 2003 to 2020 comparing the results of graft patency between OPCAB and ONCAB were included. We compared the overall graft occlusion between the two groups, and subgroup analyses were conducted based on different types of conduits and target territories, crossover from off-pump to on-pump rate, and the length of follow-up.

RESULTS

Sixteen RCTs were identified, with 5743 grafts in the OPCAB group and 5898 in the ONCAB group. OPCAB was associated with a higher risk of occlusion in the overall graft (RR: 1.31; 95% CI, 1.17-1.46), saphenous vein graft (SVG) (RR: 1.40; 95% CI, 1.23-1.59), grafts to left anterior descending (LAD) territory (RR: 1.52; 95% CI, 1.11-2.08) and left circumflex artery (LCX) territory (RR: 1.45; 95% CI, 1.19-1.76), while no significant difference was observed between the two groups in respect of arterial conduits and grafts to right coronary artery (RCA) territory. Furthermore, the lower crossover rate and longer length of follow-up appeared to reduce the association between OPCAB and lower graft patency.

CONCLUSIONS

The current meta-analysis indicates that, compared with ONCAB, graft patency is poorer with OPCAB for overall grafts, SVG grafts, grafts to LAD and LCX territories, whereas the results remain comparable for arterial conduits and grafts to RCA territory.