Frequency and Predictors of Internal Mammary Artery Graft Failure and Subsequent Clinical Outcomes: Insights From the Project of Ex-vivo Vein Graft Engineering via Transfection (PREVENT) IV Trial

Impact of Multiarterial Revascularization on Long-term Major Adverse Cardiovascular Events After Coronary Bypass in 23,798 Patients

BACKGROUND

This study evaluated the association between bypass grafting with multiarterial grafts (MAG) and single arterial grafts (SAG) and all-cause mortality and major adverse cardiovascular and cerebrovascular events (MACCE), overall and across different patient subgroups from a Middle Eastern nation.

METHODS

This single-center retrospective cohort study included 23,798 patients. MAG and SAG groups were balanced using inverse probability weighting (IPW). Associations between MAG and outcomes were assessed using Cox regression. A series of covariate-adjusted Cox models were conducted to evaluate the effect of MAG on outcomes at different levels of independent variables, including age, sex, and cardiovascular risk factors.

RESULTS

In the study population (73.9% were men, 65.11 ± 9.94 years), 986 patients (4.1%) underwent MAG. Compared with the SAG group, MAG had lower crude mortality (14.1% vs 21.6%) and MACCE (28.8% vs 34.7%) rates during a median follow-up of 9.23 years (quartile 1-quartile 3, 9.13-9.33 years). Although MAG was significantly associated with reduced risk of study outcomes at the univariate level, these associations disappeared after matching (all-cause mortality (IPW hazard ratio, 0.90; 95% CI, 0.67-1.22) and MACCEs (IPW hazard ratio, 0.94; 95% CI, 0.76-1.15). However, covariate-adjusted models indicated that MAG was associated with a significantly reduced risk of adverse events, particularly MACCEs, in men, younger patients, and those without risk factors.

CONCLUSIONS

MAG was not associated with improved postsurgery outcomes among the total coronary artery bypass graft population. Our findings, however, should be interpreted in the context of a relatively low total institutional MAG burden. Choosing a second arterial conduit over saphenous vein grafts in specific patient subgroups might be reasonable. This hypothesis-generating finding should be investigated in future clinical trials in these patients.

Multi-slice CT coronary angiography versus invasive coronary angiography in the assessment of graft patency after coronary artery bypasses graft surgery

BACKGROUND

The long-term patency of arterial and venous grafts is crucial for the success of CABG. This study was designed to investigate graft patency using 128-slice coronary computed tomography angiography (CCTA) and compared the results with those obtained using invasive coronary angiography (ICA). In this observational cross-sectional study, we included 40 symptomatic post-CABG patients underwent CCTA and ICA within the same month.

RESULTS

Fifty-five percent were aged more than 60 years, and 80% were males. 67.5% had diabetes, 90% had hypertension, and 30% were smokers. Mean body mass index was 28.89 ± 5.17 kg/m2. Mean duration since CABG was 5.25 ± 4.04 years. In total, 124 native vessels and 97 grafts were assessed using CCTA and ICA. CCTA delineated 8 non-cannulated venous grafts and 6 non-cannulated left internal mammary artery grafts. CCTA required a significantly lower radiation dose (1165.77 ± 123.54 vs. 47,589.78 ± 6967.53, p < 0.001).

CONCLUSION

CCTA can be as accurate as ICA in assessing bypass grafts with less radiation dose, providing a non-invasive reliable tool for evaluation.

Graft Failure After Coronary Artery Bypass Grafting and Its Association With Patient Characteristics and Clinical Events: A Pooled Individual Patient Data Analysis of Clinical Trials With Imaging Follow-Up

BACKGROUND

Graft patency is the postulated mechanism for the benefits of coronary artery bypass grafting (CABG). However, systematic graft imaging assessment after CABG is rare, and there is a lack of contemporary data on the factors associated with graft failure and on the association between graft failure and clinical events after CABG.

METHODS

We pooled individual patient data from randomized clinical trials with systematic CABG graft imaging to assess the incidence of graft failure and its association with clinical risk factors. The primary outcome was the composite of myocardial infarction or repeat revascularization occurring after CABG and before imaging. A 2-stage meta-analytic approach was used to evaluate the association between graft failure and the primary outcome. We also assessed the association between graft failure and myocardial infarction, repeat revascularization, or all-cause death occurring after imaging.

RESULTS

Seven trials were included comprising 4413 patients (mean age, 64.4±9.1 years; 777 [17.6%] women; 3636 [82.4%] men) and 13 163 grafts (8740 saphenous vein grafts and 4423 arterial grafts). The median time to imaging was 1.02 years (interquartile range [IQR], 1.00-1.03). Graft failure occurred in 1487 (33.7%) patients and in 2190 (16.6%) grafts. Age (adjusted odds ratio [aOR], 1.08 [per 10-year increment] [95% CI, 1.01-1.15]; P=0.03), female sex (aOR, 1.27 [95% CI, 1.08-1.50]; P=0.004), and smoking (aOR, 1.20 [95% CI, 1.04-1.38]; P=0.01) were independently associated with graft failure, whereas statins were associated with a protective effect (aOR, 0.74 [95% CI, 0.63-0.88]; P<0.001). Graft failure was associated with an increased risk of myocardial infarction or repeat revascularization occurring between CABG and imaging assessment (8.0% in patients with graft failure versus 1.7% in patients without graft failure; aOR, 3.98 [95% CI, 3.54-4.47]; P<0.001). Graft failure was also associated with an increased risk of myocardial infarction or repeat revascularization occurring after imaging (7.8% versus 2.0%; aOR, 2.59 [95% CI, 1.86-3.62]; P<0.001). All-cause death after imaging occurred more frequently in patients with graft failure compared with patients without graft failure (11.0% versus 2.1%; aOR, 2.79 [95% CI, 2.01-3.89]; P<0.001).

CONCLUSIONS

In contemporary practice, graft failure remains common among patients undergoing CABG and is strongly associated with adverse cardiac events.

Internal thoracic artery graft failure and recurrence of symptoms following single-vessel coronary artery bypass graft surgery

OBJECTIVES

Coronary events and disease recurrence following coronary artery bypass (CABG) surgery could derive from either failure in the internal thoracic artery (ITA) graft, failure in other conduits or progressive disease in the coronaries. We aim to estimate the contribution of ITA graft failure to the recurrence of symptoms after CABG surgery.

METHODS

Within the Swedish Web System for Enhancement and Development of Evidence-Based Care in Heart Disease Evaluated According to Recommended Therapies registry, we identified patients who had coronary artery bypass grafting from 1997 to 2020 with a single-vessel ITA graft bypass. Deaths, postoperative incidence of coronary angiography and the presence of a failed graft at the time of the angiography were recorded.

RESULTS

The study population consisted of 1939 patients with a mean follow-up time (SD) of 17.2 (5.6) years. The cumulative incidence (95% CI) at 20 years for a first clinically-driven postoperative angiography was 38.6% (36.2-41.1). A failed ITA graft was reported in 16.4% of the angiographies.

CONCLUSIONS

A substantial part of recurrent symptoms of coronary artery disease do not seem to be related to ITA failure. Disease progression in the native coronary vessels may instead be the main driver of symptom recurrence.

Instantaneous wave free ratio value impact on left internal mammary artery graft patency

OBJECTIVES

To assess whether instantaneous wave - free ratio (iFR) value is associated with left internal mammary artery (LIMA) graft failure at 12 months follow-up post coronary artery bypass graft (CABG).

BACKGROUND

Data suggests bypass to a non-significant left anterior descending artery (LAD) lesion due to visual over-estimation may lead to LIMA graft failure. Implementing iFR may result in better arterial graft patency.

METHODS

In iCABG (iFR guided CABG) study patients planned to undergo an isolated CABG procedure was prospectively enrolled and iFR was performed for LAD. Coronary computed tomography angiography was performed at 2 and 12 months follow-up. The primary endpoint of this study was to determine the rate of LIMA graft occlusion or hypoperfusion at 2 and 12-months follow-up. We considered a composite secondary endpoint of Major adverse cardiovascular and cerebrovascular event (MACCE) as a secondary outcome.

RESULTS

In total 69 patients were included with no differences regarding age, sex and risk factors. At 2 months, 50 of LIMAs with pre-CABG iFR median 0.855 (0.785 - 0.892) were patent. Hypoperfusion was found in 8 LIMAs (median iFR 0.88 (0.842 - 0.90)). While, 7 LIMAs (median iFR 0.91 (0.88 - 0.96)) were occluded (p = 0.04). At 12 months, when iFR of LAD was >0.85: just 12 (31.6% out of all patent LIMAS) grafts were patent and 24 (100.0% out of all hypoperfused/occluded) grafts were hypoperfused or occluded (p < 0.001). In terms of MACCE, no difference (p = 1.0) was found between all 3 groups divided according to iFR value.

CONCLUSIONS

Instantaneous wave - free ratio value above 0.85 in LAD is a powerful tool predicting LIMA graft failure at 1-year follow up period.

Clinical implications of inflammation in atheroma formation and novel therapies in cardiovascular diseases

Cardiovascular diseases (CVD) are the leading causes of death and disability in the world. Among all CVD, the most common is coronary artery disease (CAD). CAD results from the complications promoted by atherosclerosis, which is characterized by the accumulation of atherosclerotic plaques that limit and block the blood flow of the arteries involved in heart oxygenation. Atherosclerotic disease is usually treated by stents implantation and angioplasty, but these surgical interventions also favour thrombosis and restenosis which often lead to device failure. Hence, efficient and long-lasting therapeutic options that are easily accessible to patients are in high demand. Advanced technologies including nanotechnology or vascular tissue engineering may provide promising solutions for CVD. Moreover, advances in the understanding of the biological processes underlying atherosclerosis can lead to a significant improvement in the management of CVD and even to the development of novel efficient drugs. To note, over the last years, the observation that inflammation leads to atherosclerosis has gained interest providing a link between atheroma formation and oncogenesis. Here, we have focused on the description of the available therapy for atherosclerosis, including surgical treatment and experimental treatment, the mechanisms of atheroma formation, and possible novel therapeutic candidates such as the use of anti-inflammatory treatments to reduce CVD.

Long-term outcomes of percutaneous revascularization for internal mammary artery-left anterior descending artery bypass failure

Despite the excellent long-term results of internal mammary artery (IMA)-left anterior descending (LAD) bypass, percutaneous revascularization of IMA is sometimes required for IMA-LAD bypass failure. However, its clinical outcomes have not been fully elucidated. The aim of this study was to investigate the long-term clinical outcomes, including target lesion revascularization (TLR) following contemporary percutaneous revascularization of failed IMA bypass graft. We examined data of 59 patients who had undergone percutaneous revascularization of IMA due to IMA-LAD bypass failure at nine hospitals. Patients with IMA graft used for Y-composite graft or sequential bypass graft were excluded. The incidence of TLR was primarily examined, whereas other clinical outcomes including cardiac death, myocardial infarction, and target vessel revascularization were also evaluated. Mean age of the enrolled patients was 67.4 ± 11.3 years, and 74.6% were men. Forty patients (67.8%) had anastomotic lesions, and 17 (28.8%) underwent revascularization within three months after bypass surgery. Procedural success was achieved in 55 (93.2%) patients. Stent implantation was performed in 13 patients (22.0%). During a median follow-up of 1401 days (interquartile range, 282-2521 days), TLR was required in six patients (8.5% at 1, 3, and 5 years). Patients who underwent percutaneous revascularization within 3 months after surgery tended to have a higher incidence of TLR. Clinical outcomes of IMA revascularization for IMA-LAD bypass failure were acceptable.

Strategies to counteract adverse remodeling of vascular graft: A 3D view of current graft innovations

Vascular grafts are widely used for vascular surgeries, to bypass a diseased artery or function as a vascular access for hemodialysis. Bioengineered or tissue-engineered vascular grafts have long been envisioned to take the place of bioinert synthetic grafts and even vein grafts under certain clinical circumstances. However, host responses to a graft device induce adverse remodeling, to varied degrees depending on the graft property and host's developmental and health conditions. This in turn leads to invention or failure. Herein, we have mapped out the relationship between the design constraints and outcomes for vascular grafts, by analyzing impairment factors involved in the adverse graft remodeling. Strategies to tackle these impairment factors and counteract adverse healing are then summarized by outlining the research landscape of graft innovations in three dimensions-cell technology, scaffold technology and graft translation. Such a comprehensive view of cell and scaffold technological innovations in the translational context may benefit the future advancements in vascular grafts. From this perspective, we conclude the review with recommendations for future design endeavors.

Impact of diabetes mellitus on long-term clinical and graft outcomes after off-pump coronary artery bypass grafting with pure bilateral skeletonized internal thoracic artery grafts

BACKGROUND

The effect of diabetes mellitus (DM) on the long-term outcomes of coronary artery bypass graft (CABG) remained debatable and various strategies exist for CABG; hence, clarifying the effects of DM on CABG outcomes is difficult. The current study aimed to evaluate the effect of DM on clinical and graft-related outcomes after CABG with bilateral internal thoracic artery (BITA) grafts.

METHODS

From January 2001 to December 2017, 3395 patients who underwent off-pump CABG (OPCAB) with BITA grafts were enrolled. The study population was stratified according to preoperative DM. The primary endpoint was cardiac death and the secondary endpoints were myocardial infarction (MI), revascularization, graft failure, stroke, postoperative wound infection, and a composite endpoint of cardiac death, MI, and revascularization. Multiple sensitivity analyses, including Cox proportional hazard regression and propensity-score matching analyses, were performed to adjust baseline differences.

RESULTS

After CABG, the DM group showed similar rates of cardiac death, MI, or revascularization and lower rates of graft failure at 10 years (DM vs. non-DM, 19.0% vs. 24.3%, hazard ratio [HR] 0.711, 95% confidence interval [CI] 0.549-0.925; P = 0.009) compared to the non-DM group. These findings were consistent after multiple sensitivity analyses. In the subgroup analysis, the well-controlled DM group, which is defined as preoperative hemoglobin A1c (HbA1c) of < 7%, showed lower postoperative wound infection rates (well-controlled DM vs. poorly controlled DM, 3.7% vs. 7.3%, HR 0.411, 95% CI 0.225-0.751; P = 0.004) compared to the poorly controlled DM group, which was consistent after propensity-score matched analysis.

CONCLUSIONS

OPCAB with BITA grafts showed excellent and comparable long-term clinical outcomes in patients with and without DM. DM might have a protective effect on competition and graft failure of ITA. Strict preoperative hyperglycemia control with target HbA1c of < 7% might reduce postoperative wound infection and facilitate the use of BITA in CABG.

One-stage hybrid coronary revascularization for the treatment of multivessel coronary artery disease— Periprocedural and long-term results from the “HYBRID-COR” feasibility study

Background

The constant growth of interest in hybrid coronary artery revascularization (HCR) is apparent. Yet, few studies report outcomes of the one-stage HCR. Consequently, the status of such procedures is not adequately supported in clinical guidelines. The aim of this study was to report the safety, feasibility, and long term-outcomes of the one-stage HCR.

Methods and results

Patients were enrolled in the prospective one-stage hybrid coronary revascularization program (HYBRID-COR). They underwent a one-stage hybrid revascularization procedure while on double antiplatelet therapy (DAPT) with Ticagrelor: endoscopic atraumatic coronary artery bypass grafting (EACAB) for revascularization of the left anterior descending (LAD) artery and percutaneous intervention in non-LAD arteries with contemporary drug-eluting stents. The composite primary endpoint included MACCE (major adverse cardiac and cerebrovascular events: death, myocardial infarction, stroke, and repeated revascularization) in long-term observation. The study cohort consisted of 30 patients (68% male) with stable coronary artery disease (26.7%) and unstable angina (73.3%). Procedural success was 100%. No death, myocardial infarction (MI), or stroke were observed in the perioperative period. One patient (3.3%) required chest revision and blood transfusion due to surgical bleeding. Kidney injury was noted in two patients (6.6%). In a long-term follow-up (median; IQR: 4.25; 2.62–4.69 years), two patients (6.6%) underwent repeated revascularization and one patient (3.3%) died due to MI. The overall primary endpoint rate was 9.9%.

Conclusion

One-stage hybrid revascularization, on DAPT, is a feasible, safe, and efficient way of achieving complete revascularization in selected patients. The complication rate is low and acceptable. Further randomized trials are required.

Diagnostic and Management Strategies in Patients with Late Recurrent Angina after Coronary Artery Bypass Grafting

PURPOSE OF REVIEW

This review will outline the current evidence on the anatomical, functional, and physiological tools that may be applied in the evaluation of patients with late recurrent angina after coronary artery bypass grafting (CABG). Furthermore, we discuss management strategies and propose an algorithm to guide decision-making for this complex patient population.

RECENT FINDINGS

Patients with prior CABG often present with late recurrent angina as a result of bypass graft failure and progression of native coronary artery disease (CAD). These patients are generally older, have a higher prevalence of comorbidities, and more complex atherosclerotic lesion morphology compared to CABG-naïve patients. In addition, guideline recommendations are based on studies in which post-CABG patients have been largely excluded. Several invasive and non-invasive diagnostic tools are currently available to assess graft patency, the hemodynamic significance of native CAD progression, left ventricular function, and myocardial viability. Such tools, in particular the latest generation coronary computed tomography angiography, are part of a systematic diagnostic work-up to guide optimal repeat revascularization strategy in patients presenting with late recurrent angina after CABG.

Competitive Flow in Vein Composite Grafts Based on the Left Internal Thoracic Artery: Early and 1-Year Angiographic Analyses

We assessed the incidence of competitive flow with early postoperative angiograms in patients who received a "no-touch" saphenous vein (NT SV) composite graft and reexamined the status of competitive flow at 1-year. Early postoperative angiograms were performed in 806 patients who underwent myocardial revascularization using a NT SV Y-composite graft based on the in situ left internal thoracic artery (LITA). Competitive conduit flow was observed in 102 distal anastomoses (102 of 3039 [3.4%] anastomoses) of 94 patients (94 of 806 [11.7%]; NT SV competitive flow in 74 and LITA competitive flow in 20). Of the 94 patients, 63 patients (50 with NT SV competition and 13 with LITA competition) were re-evaluated with 1-year postoperative angiograms. Fifty-six competitive NT SV conduits in 50 patients were reevaluated at 1-year postoperatively: 44 (78.6%) early competitive anastomoses had become patent and 12 (21.4%) were occluded. NT SV with pedicle tissue showed a higher tendency of being perfectly patent at 1-year postoperatively than NT SV without pedicle tissue (17 of 40 [42.5%] vs 2 of 16 [12.5%]; P = 0.007). Thirteen competitive LITA conduit anastomoses in 13 patients were reevaluated 1-year postoperatively: 9 (69.2%) early competitive anastomoses had become patent and 4 (30.8%) were occluded. Competitive flow was shown on early postoperative angiograms in 3.4% of distal anastomoses in patients who received NT SV Y-composite grafts. Approximately 80% of the competitive NT SV conduits were patent 1-year postoperatively, and perfect patency rates were higher in patients who had received NT SV with pedicle tissue than in patients who had received NT SV without pedicle tissue.

Three-dimensional QCA-based vessel fractional flow reserve (vFFR) in Heart Team decision-making: a multicentre, retrospective, cohort study

OBJECTIVES

To evaluate the feasibility of three-vessel three-dimensional (3D) quantitative coronary angiography (QCA)-based fractional flow reserve (FFR) computation in patients discussed within the Heart Team in whom the treatment decision was based on angiography alone, and to evaluate the concordance between 3D QCA-based vessel FFR (vFFR)-confirmed functional lesion significance and revascularisation strategy as proposed by the Heart Team.

DESIGN

Retrospective, cohort.

SETTING

3D QCA-based FFR indices have not yet been evaluated in the context of Heart Team decision-making; consecutive patients from six institutions were screened for eligibility and three-vessel vFFR was computed by blinded analysts.

PARTICIPANTS

Consecutive patients with chronic coronary syndrome or unstable angina referred for Heart Team consultation. Exclusion criteria involved: presentation with acute myocardial infarction (MI), significant valve disease, left ventricle ejection fraction <30%, inadequate quality of angiogram precluding vFFR computation in all three epicardial coronary arteries (ie, absence of a minimum of two angiographic projections with views of at least 30° apart, substantial foreshortening/overlap of the vessel, poor contrast medium injection, ostial lesions, chronic total occlusions).

PRIMARY AND SECONDARY OUTCOME MEASURES

Discordance between vFFR-confirmed lesion significance and revascularisation was assessed as the primary outcome measure. Rates of major adverse cardiac events (MACE) defined as cardiac death, MI and clinically driven revascularisation were reported.

RESULTS

Of a total of 1003 patients were screened for eligibility, 416 patients (age 65.6±10.6, 71.2% male, 53% stable angina) were included. The most important reason for screening failure was insufficient quality of the angiogram (43%). Discordance between vFFR confirmed lesion significance and revascularisation was found in 124/416 patients (29.8%) corresponding to 149 vessels (46/149 vessels (30.9%) were reclassified as significant and 103/149 vessels (69.1%) as non-significant by vFFR). Over a median of 962 days, the cumulative incidence of MACE was 29.7% versus 18.5% in discordant versus concordant patients (p=0.031).

CONCLUSIONS

vFFR computation is feasible in around 40% of the patients referred for Heart Team discussion, a limitation that is mostly based on insufficient quality of the angiogram. Three vessel vFFR screening indicated discordance between vFFR confirmed lesion significance and revascularisation in 29.8% of the patients.

Contemporary coronary artery bypass graft surgery and subsequent percutaneous revascularization

Patients who have undergone coronary artery bypass graft (CABG) surgery are susceptible to bypass graft failure and progression of native coronary artery disease. Although the saphenous vein graft (SVG) was traditionally the most-used conduit, arterial grafts (including the left and right internal thoracic arteries and the radial artery) have improved patency rates. However, the need for secondary revascularization remains common, and percutaneous coronary intervention (PCI) has become the most common modality of secondary revascularization after CABG surgery. Procedural characteristics and clinical outcomes differ considerably from those associated with PCI in patients without previous CABG surgery, owing to altered coronary anatomy and differences in conduit pathophysiology. In particular, SVG PCI carries an increased risk of complications, and operators are shifting their focus towards embolic protection strategies and complex native-vessel interventions, increasingly using SVGs as conduits to facilitate native-vessel PCI rather than pursuing SVG PCI. In this Review, we discuss the differences in conduit pathophysiology, changes in CABG surgery techniques, and the latest evidence in terms of PCI in patients with previous CABG surgery, with a particular emphasis on safety and long-term efficacy. We explore the subject of contemporary CABG surgery and subsequent percutaneous revascularization in this complex patient population.

Impact of Conventional Cardiovascular Risk Factors on Left Internal Mammary Artery Graft Disease

Background:

The development of atherosclerosis was considered as the common cause of the stenosis of coronary artery grafts. Left internal mammary artery (LIMA) was the best artery graft for further effectiveness of coronary artery bypass grafting (CABG). We sought to assess the impact of known conventional cardiovascular risk factors (RFs) on LIMA graft stenosis.

Methods:

A retrospective study including 618 participants, who had recurrence of chest pain after CABG, aged ≥18 years, hospitalized for coronary angiography in Beijing Anzhen hospital between 2010 and 2017 was performed. All the participants were confirmed to have LIMA graft. Multivariate analysis was conducted to determine the relationship between conventional RFs and LIMA graft stenosis.

Results:

Of the study, 220 (35.6%) participants continued to smoke, 504 (81.6%) were overweight or obese, and 411 (66.5%) and 242 (39.2%) reported concomitant hypertension and diabetes, respectively. LIMA graft stenosis occurred in 161 participants (26.1%). Postoperative smoking, a CABG duration of ≥10 years and hyperglycemia without diabetes had an increased risk of LIMA graft stenosis, the odds ratio (OR) was 1.86 [95% confidence interval (CI): 1.26–2.78], 2.24 (95%CI:1.33–3.478), and 2.44(95% CI:1.39–4.32), respectively. Statin use (OR, 0.28; 95% CI: 0.25–0.5) and low-density lipoprotein cholesterol (LDL-C) &lt; 1.8 mmol/L (OR, 0.27; 95% CI: 0.14–0.53) had a significantly decreased risk of LIMA graft stenosis. While, only 15.4% (95/618) achieved the target LDL-C level.

Conclusions:

Postoperative smoking and hyperglycemia without diabetes had an increased risk of LIMA graft stenosis. Statin use and LDL-C &lt;1.8 mmol/L decreased the risk.

CCL2 loaded microparticles promote acute patency in silk-based vascular grafts implanted in rat aortae

Cardiovascular disease is the leading cause of death worldwide, often associated with coronary artery occlusion. A common intervention for arterial blockage utilizes a vascular graft to bypass the diseased artery and restore downstream blood flow; however, current clinical options exhibit high long-term failure rates. Our goal was to develop an off-the-shelf tissue-engineered vascular graft capable of delivering a biological payload based on the monocyte recruitment factor C-C motif chemokine ligand 2 (CCL2) to induce remodeling. Bi-layered silk scaffolds consisting of an inner porous and outer electrospun layer were fabricated using a custom blend of Antherea Assama and Bombyx Mori silk (lyogel). Lyogel silk scaffolds alone (LG), and lyogel silk scaffolds containing microparticles (LGMP) were tested. The microparticles (MPs) were loaded with either CCL2 (LGMP+) or water (LGMP-). Scaffolds were implanted as abdominal aortic interposition grafts in Lewis rats for 1 and 8 weeks. 1-week implants exhibited patency rates of 50% (7/14), 100% (10/10), and 100% (5/5) in the LGMP-, LGMP+, and LG groups, respectively. The significantly higher patency rate for the LGMP+ group compared to the LGMP- group (p = 0.0188) suggests that CCL2 can prevent acute occlusion. Immunostaining of the explants revealed a significantly higher density of macrophages (CD68+ cells) within the outer vs. inner layer of LGMP- and LGMP+ constructs but not in LG constructs. After 8 weeks, there were no significant differences in patency rates between groups. All patent scaffolds at 8 weeks showed signs of remodeling; however, stenosis was observed within the majority of explants. This study demonstrated the successful fabrication of a custom blended silk scaffold functionalized with cell-mimicking microparticles to facilitate controlled delivery of a biological payload improving their in vivo performance. STATEMENT OF SIGNIFICANCE: This study outlines the development of a custom blended silk-based tissue-engineered vascular graft (TEVG) for use in arterial bypass or replacement surgery. A custom mixture of silk was formulated to improve biocompatibility and cellular binding to the tubular scaffold. Many current approaches to TEVGs include cells that encourage graft cellularization and remodeling; however, our technology incorporates a microparticle based delivery platform capable of delivering bioactive molecules that can mimic the function of seeded cells. In this study, we load the TEVGs with microparticles containing a monocyte attractant and demonstrate improved performance in terms of unobstructed blood flow versus blank microparticles. The acellular nature of this technology potentially reduces risk, increases reproducibility, and results in a more cost-effective graft when compared to cell-based options.

Saphenous Vein Graft Failure: From Pathophysiology to Prevention and Treatment Strategies

Saphenous vein grafts (SVGs) remain the most frequently used conduits in coronary artery bypass graft surgery (CABG). Despite advances in surgical techniques and pharmacotherapy, SVG failure rates remain high, often leading to repeat coronary revascularization. The no-touch SVG harvesting technique (minimal graft manipulation with preservation of vasa vasorum and nerves) reduces the risk of SVG failure, whereas the effect of the off-pump technique on SVG patency remains unclear. Use of buffered storage solutions, intraoperative graft flow measurement, careful selection of the target vessels, and physiological assessment of the native coronary circulation before CABG may also reduce the incidence of SVG failure. Perioperative aspirin and high-intensity statin administration are the cornerstones of secondary prevention after CABG. Dual antiplatelet therapy is recommended for off-pump CABG and in patients with a recent acute coronary syndrome. Intermediate (30%-60%) SVG stenoses often progress rapidly. Stenting of intermediate SVG stenoses failed to improve outcomes; hence, treatment focuses on strict control of coronary artery disease risk factors. Redo CABG is associated with higher perioperative mortality compared with percutaneous coronary intervention (PCI); hence, the latter is preferred for most patients requiring repeat revascularization after CABG. SVG PCI is limited by high rates of no-reflow and a high incidence of restenosis during follow-up. Drug-eluting and bare metal stents provide similar long-term outcomes in SVG PCI. Embolic protection devices reduce no-reflow and should be used when feasible. PCI of the corresponding native coronary artery is associated with better short- and long-term outcomes and is preferred over SVG PCI, if technically feasible.

Skeletonized vs Pedicled Internal Mammary Artery Graft Harvesting in Coronary Artery Bypass Surgery: A Post Hoc Analysis From the COMPASS Trial

Importance

The relative safety and patency of skeletonized vs pedicled internal mammary artery grafts in patients undergoing coronary artery bypass graft (CABG) surgery are unknown.

Objective

To investigate the association of skeletonized vs pedicled harvesting with internal mammary artery graft patency and clinical outcomes 1 year after CABG surgery.

Design, Setting, and Participants

This study was a post hoc analysis of the multicenter, randomized, double-blind, placebo-controlled Cardiovascular Outcomes for People Using Anticoagulation Strategies (COMPASS) clinical trial, which enrolled 27 395 patients from 602 centers in 33 countries from March 2013 through May 2016. Eligibility criteria for the trial included CABG surgery for coronary artery disease with at least 2 grafts implanted and an estimated glomerular filtration rate of at least 30 mL/min. A total of 1002 of 1448 patients were randomized to the CABG arm of the COMPASS trial and underwent skeletonized (282 [28.1%]) or pedicled (720 [71.9%]) internal mammary artery harvesting. The patients had evaluable angiography results 1 year after surgery. Data were analyzed from October 11, 2019, to May 14, 2020.

Interventions

Patients underwent graft harvesting with either the pedicled technique or skeletonized technique.

Main Outcomes and Measures

The primary outcome was graft occlusion 1 year after CABG surgery, as assessed by computed tomography angiography.

Results

A total of 1002 patients underwent skeletonized (282 [28.1%]; mean [SD] age, 65.9 [8.1] years; 229 men [81.2%]; 194 White patients [68.8%]) or pedicled (720 [71.9%]; mean [SD] age, 64.8 [7.6] years; 603 men [83.8%]; 455 White patients [63.2%]) internal mammary artery harvesting. Rates of internal mammary artery graft occlusion 1 year after CABG surgery were higher in the skeletonized group than in the pedicled group (33 of 344 [9.6%] vs 30 of 764 [3.9%]; graft-level adjusted odds ratio, 2.41; 95% CI, 1.39-4.20; P = .002), including the left internal mammary artery to left anterior descending artery (21 of 289 [7.3%] vs 25 of 725 [3.4%]; graft-level adjusted odds ratio, 2.10; 95% CI, 1.14-3.88, P = .02). After a mean follow-up of 23 months, skeletonized graft harvesting was also associated with a higher rate of major adverse cardiovascular events (20 [7.1%] vs 15 [2.1%]; adjusted hazard ratio, 3.19; 95% CI, 1.53-6.67; P = .002) and repeated revascularization (14 [5.0%] vs 10 [1.4%]; adjusted hazard ratio, 2.75; 95% CI, 1.10-6.88; P = .03).

Conclusions and Relevance

This post hoc analysis of the COMPASS randomized clinical trial found that harvesting of the internal mammary artery during CABG surgery using a skeletonized technique was associated with a higher rate of graft occlusion and worse clinical outcomes than the traditional pedicled technique. Future randomized clinical trials are needed to establish the safety and patency of the skeletonized technique.

Trial Registration

ClinicalTrials.gov Identifier: NCT01776424.

Aortic remodeling and competitive flow after surgical treatment of aortic dissection

Aortic remodeling after dissection is poorly understood and remains a focus of current research. In the present report, we have described the cases of two patients with acute lower extremity ischemia related to malperfusion from aortic dissection treated with extra-anatomic axillobifemoral bypass. During long-term follow-up, aortic remodeling led to reinstitution of flow through the native aorta. This resulted in competitive flow, leading to complete thrombosis of the extra-anatomic conduits. These cases highlight the occurrence of spontaneous aortic recanalization and subsequent competitive flow, two vascular phenomena that are not well understood but can significantly affect patient outcomes.

The association between coronary graft patency and clinical status in patients with coronary artery disease

The concept of a direct association between coronary graft patency and clinical status is generally accepted. However, the relationship is more complex and variable than usually thought. Key issues are the lack of a common definition of graft occlusion and of a standardized imaging protocol for patients undergoing coronary bypass surgery. Factors like the type of graft, the timing of the occlusion, and the amount of myocardium at risk, as well as baseline patients' characteristics, modulate the patency-to-clinical status association. Available evidence suggests that graft occlusion is more often associated with non-fatal events rather than death. Also, graft failure due to competitive flow is generally a benign event, while graft occlusion in a graft-dependent circulation is associated with clinical symptoms. In this systematic review, we summarize the evidence on the association between graft status and clinical outcomes.

Extracellular Vesicles Derived from Primary Adipose Stromal Cells Induce Elastin and Collagen Deposition by Smooth Muscle Cells within 3D Fibrin Gel Culture

Macromolecular components of the vascular extracellular matrix (ECM), particularly elastic fibers and collagen fibers, are critical for the proper physiological function of arteries. When the unique biomechanical combination of these fibers is disrupted, or in the ultimate extreme where fibers are completely lost, arterial disease can emerge. Bioengineers in the realms of vascular tissue engineering and regenerative medicine must therefore ideally consider how to create tissue engineered vascular grafts containing the right balance of these fibers and how to develop regenerative treatments for situations such as an aneurysm where fibers have been lost. Previous work has demonstrated that the primary cells responsible for vascular ECM production during development, arterial smooth muscle cells (SMCs), can be induced to make new elastic fibers when exposed to secreted factors from adipose-derived stromal cells. To further dissect how this signal is transmitted, in this study, the factors were partitioned into extracellular vesicle (EV)-rich and EV-depleted fractions as well as unseparated controls. EVs were validated using electron microscopy, dynamic light scattering, and protein quantification before testing for biological effects on SMCs. In 2D culture, EVs promoted SMC proliferation and migration. After 30 days of 3D fibrin construct culture, EVs promoted SMC transcription of the elastic microfibril gene FBN1 as well as SMC deposition of insoluble elastin and collagen. Uniaxial biomechanical properties of strand fibrin constructs were no different after 30 days of EV treatment versus controls. In summary, it is apparent that some of the positive effects of adipose-derived stromal cells on SMC elastogenesis are mediated by EVs, indicating a potential use for these EVs in a regenerative therapy to restore the biomechanical function of vascular ECM in arterial disease.

Imaging Features of Complications after Coronary Interventions and Surgical Procedures

Coronary artery interventions and surgical procedures are used in the treatment of coronary artery disease and some congenital heart diseases. Cardiac and noncardiac complications can occur at variable times after these procedures, with the clinical presentation ranging from asymptomatic to devastating symptoms. Invasive coronary angiography is the reference standard modality used in the evaluation of coronary arteries, with intravascular US and optical coherence tomography providing high-resolution information regarding the vessel wall. CT is the mostly commonly used noninvasive imaging modality in the evaluation of coronary artery intervention complications and allows assessment of the stent, lumen of the stent, lumen of the coronary arteries, and extracoronary structures. MRI is limited to the evaluation of the proximal coronary arteries but allows comprehensive evaluation of the myocardium, including ischemia and infarction. The authors review the clinical symptoms and pathophysiologic and imaging features of various complications of coronary artery interventions and surgical procedures. Complications of percutaneous coronary interventions are discussed, including restenosis, thrombosis, dissection of coronary arteries or the aorta, coronary wall rupture or perforation, stent deployment failure, stent fracture, stent infection, stent migration or embolism, and reperfusion injury. Complications of several surgical procedures are reviewed, including coronary artery bypass grafting, coronary artery reimplantation procedure (for anomalous origin from opposite sinuses or the pulmonary artery or as part of surgical procedures such as arterial switching surgery and the Bentall and Cabrol procedures), coronary artery unroofing, and the Takeuchi procedure. Online supplemental material is available for this article. ^©RSNA, 2021.

Pedicled versus skeletonized internal thoracic artery grafts: a randomized trial

OBJECTIVE

Concerns have been raised regarding whether skeletonization of the internal thoracic artery could damage the graft and thereby reduces its patency. The objective of this study was to compare patency rates at mid- and long-term follow-up between pedicled and skeletonized left internal thoracic artery grafts.

METHODS

This randomized controlled trial included 109 patients undergoing coronary artery bypass surgery. The patients were assigned to receive either one pedicled or one skeletonized left internal thoracic artery graft to the left anterior descending artery. Follow-up was performed at 3 years with conventional angiography, and at 8 years with computed tomography angiography. Differences between patency rates were analyzed with Fisher's exact test and a generalized linear model.

RESULTS

The patency rates for pedicled and skeletonized left internal thoracic artery grafts were 46/48 (95.8%) versus 47/52 (90.4%), p = 0.44 at 3 years, and 40/43 (93.0%) versus 37/41 (90.2%), p = 0.71 at 8 years, respectively. The difference in patency rates for pedicled and skeletonized grafts was 5.4% (95% confidence interval: -4.2-14.5) at 3 years and 2.8% (95% confidence interval: -9.9-14.1) at 8 years. All failed grafts, except for one with a localized stenosis, were anastomosed to native coronary arteries with a stenosis less than 70%. Three patients suffered sternal wound infections (two in the pedicled group, one in the skeletonized group).

CONCLUSIONS

The skeletonization technique can be used without jeopardizing the patency of the left internal thoracic artery. The most important factor in graft failure was target artery stenosis below 70%.

The role of fractional flow reserve in coronary artery bypass graft surgery: a meta-analysis

OBJECTIVES

Fractional flow reserve (FFR) measures the drop in perfusion pressure across a stenosis, therefore representing its physiological effect on myocardial blood flow. Its use is widespread in percutaneous coronary interventions, though its role in coronary artery bypass graft (CABG) surgery remains uncertain. This systematic review and meta-analysis aims to evaluate current evidence on outcomes following FFR-guided CABG compared to angiography-guided CABG.

METHODS

A literature search was conducted following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify all relevant articles. Patient demographics and characteristics were extracted. The following outcomes were analysed: repeat revascularization, myocardial infarction (MI) and all-cause mortality. Pooled relative risks were analysed and their 95% confidence intervals (CIs) were estimated using random-effects models; P-value <0.05 was considered statistically significant. Heterogeneity was assessed with Cochran's Q score and quantified by I2 index.

RESULTS

Nine studies with 1146 patients (FFR: 574, angiography: 572) were included. There was no difference in MI or repeat revascularization between the 2 groups (relative risk 0.76, 95% CI 0.41-1.43; P = 0.40, and relative risk 1.28, 95% CI 0.75-2.19; P = 0.36, respectively). There was a significant reduction in all-cause mortality in the FFR-guided CABG group compared to angiography-guided CABG, which was not specifically cardiac related (relative risk 0.58, 95% CI 0.38-0.90; P = 0.02).

CONCLUSIONS

There was no reduction in repeat revascularization or postoperative MI with FFR. In this fairly small cohort, FFR-guided CABG provided a reduction in mortality, but this was not reported to be due to cardiac causes. There may be a role for FFR in CABG, but large-scale randomized trials are required to establish its value.

Development of a Semi-Automated, Bulk Seeding Device for Large Animal Model Implantation of Tissue Engineered Vascular Grafts

Vascular tissue engineering is a field of regenerative medicine that restores tissue function to defective sections of the vascular network by bypass or replacement with a tubular, engineered graft. The tissue engineered vascular graft (TEVG) is comprised of a biodegradable scaffold, often combined with cells to prevent acute thrombosis and initiate scaffold remodeling. Cells are most effectively incorporated into scaffolds using bulk seeding techniques. While our group has been successful in uniform, rapid, bulk cell seeding of scaffolds for TEVG testing in small animals using our well-validated rotational vacuum technology, this approach was not directly translatable to large scaffolds, such as those required for large animal testing or human implants. The objective of this study was to develop and validate a semi-automated cell seeding device that allows for uniform, rapid, bulk seeding of large scaffolds for the fabrication of TEVGs appropriately sized for testing in large animals and eventual translation to humans. Validation of our device revealed successful seeding of cells throughout the length of our tubular scaffolds with homogenous longitudinal and circumferential cell distribution. To demonstrate the utility of this device, we implanted a cell seeded scaffold as a carotid interposition graft in a sheep model for 10 weeks. Graft remodeling was demonstrated upon explant analysis using histological staining and mechanical characterization. We conclude from this work that our semi-automated, rotational vacuum seeding device can successfully seed porous tubular scaffolds suitable for implantation in large animals and provides a platform that can be readily adapted for eventual human use.

Outcomes following revascularization with radial artery bypass grafts: Insights from the PREVENT-IV trial

BACKGROUND

The optimal role of radial artery grafts in coronary artery bypass grafting (CABG) remains uncertain. The purpose of this study was to examine angiographic and clinical outcomes following CABG among patients who received a radial artery graft.

METHODS

Patients in the angiographic cohort of the PREVENT-IV trial were stratified based upon having received a radial artery graft or not during CABG. Baseline characteristics and 1-year angiographic and 5-year clinical outcomes were compared between patients.

RESULTS

Of 1,923 patients in the angiographic cohort of PREVENT-IV, 117 received a radial artery graft. These patients had longer surgical procedures (median 253 vs 228 minutes, P < .001) and had a greater number of grafts placed (P < .0001). Radial artery grafts had a graft-level failure rate of 23.0%, which was similar to vein grafts (25.2%) and higher than left internal mammary artery grafts (8.3%). The hazard of the composite clinical outcome of death, myocardial infarction, or repeat revascularization was similar for both cohorts (adjusted hazard ratio 0.896, 95% CI 0.609-1.319, P = .58). Radial graft failure rates were higher when used to bypass moderately stenotic lesions (<75% stenosis, 37% failure) compared with severely stenotic lesions (≥75% stenosis, 15% failure).

CONCLUSIONS

Radial artery grafts had early failure rates comparable to saphenous vein and higher than left internal mammary artery grafts. Use of a radial graft was not associated with a different rate of death, myocardial infarction, or postoperative revascularization. Despite the significant potential for residual confounding associated with post hoc observational analyses of clinical trial data, these findings suggest that when clinical circumstances permit, the radial artery is an acceptable alternative to saphenous vein and should be used to bypass severely stenotic target vessels.

Angiographic patency after robotic beating heart totally endoscopic coronary artery bypass grafting facilitated by automated distal anastomotic connectors

OBJECTIVES

Robotic totally endoscopic coronary artery bypass (TECAB) on the beating heart has been facilitated in our experience using distal coronary anastomotic connectors. In this study, we retrospectively reviewed graft patency in all robotic TECAB patients who underwent formal angiography at our current institution over a 5-year period.

METHODS

Between July 2013 and June 2018, 361 consecutive patients underwent robotic beating-heart TECAB. Of these patients, 121 had a follow-up angiogram, which assessed graft patency. Eighty-four patients had an angiogram as part of planned hybrid procedures and 37 patients underwent an unplanned angiogram for clinical indications. Retrospective analysis of angiographic patency and clinical outcomes was performed.

RESULTS

The mean Society of Thoracic Surgeons predicted risk of mortality was 1.8%. Single-vessel bypass was performed in 40 (33%) patients and multivessel grafting in 81 (67%). Average flow (ml/min) and pulsatility index in the grafts was 74.7 ± 39.1 and 1.42 ± 0.52, respectively. The number of grafts evaluated was 204 (130 left internal mammary artery and 74 right internal mammary artery grafts). The median time to angiography was 1.0 and 16.0 months and graft patency was 98% and 91% in the hybrid and non-hybrid groups, respectively. Overall graft patency was 95.6% (left internal mammary artery = 96%; right internal mammary artery = 93%). Left internal mammary artery to left anterior descending artery graft patency was 97%. Clinical follow-up was available for 316 (88%) patients at mean 22.5 ± 15.1 months. Freedom from major adverse cardiac events at 2 years was 92%.

CONCLUSIONS

In this consecutive series of patients undergoing formal angiography after robotic single and multivessel TECAB, we found satisfactory graft patency and 2-year clinical outcomes. Longer-term follow-up is warranted.

Incidence and Prognostic Impact of Incomplete Revascularization Documented by Coronary Angiography 1 Year After Coronary Artery Bypass Grafting

Complete revascularization (CR) at the time of coronary artery bypass graft (CABG) surgery improves long-term cardiac outcomes. No studies have previously reported angiographically confirmed CR rates post-CABG. This study's aim was to assess the impact upon long-term outcomes of CR versus incomplete revascularization (IR), confirmed by coronary angiography 1 year after CABG. Randomized On/Off Bypass Study patients who returned for protocol-specified 1-year post-CABG coronary angiograms were included. Patients with a widely patent graft supplying the major diseased artery within each diseased coronary territory were considered to have CR. Outcomes were all-cause mortality and major adverse cardiovascular events (MACE; all-cause mortality, nonfatal myocardial infarction, repeat revascularization) over the 4 years after angiography. Of the 1,276 patients, 756 (59%) had CR and 520 (41%) had IR. MACE was 13% CR versus 26% IR, p <0.001. This difference was driven by fewer repeat revascularizations (5% CR vs 18% IR; p <0.001). There were no differences in mortality (7.1% CR vs 8.1% IR, p = 0.13) or myocardial infarction (4% in both). Adjusted multivariable models confirmed CR was associated with reduced MACE (odds ratio 0.44, 95% confidence interval 0.33 to 0.58, p <0.01), but had no impact on mortality. In conclusion, CR confirmed by post-CABG angiography was associated with improved MACE but not mortality. Repeat revascularization of patients with IR, driven by knowledge of the research angiography results, may have ameliorated potential mortality differences.

FFR-guided versus coronary angiogram-guided CABG: A review and meta-analysis of prospective randomized controlled trials

BACKGROUND

Fractional flow reserve (FFR) is a well-established method for the evaluation of coronary artery stenosis before percutaneous coronary intervention. However, whether FFR assessment should be routinely used before coronary artery bypass graft surgery (CABG) remains unclear. A meta-analysis of prospectively randomized controlled trials (PRCTs) was carried out to compare the outcomes of FFR-guided CABG vs coronary angiography (CAG)-guided CABG.

METHOD

The meta-analysis adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two PRCTs (the FARGO and GRAFFITI trials) were found and included reporting data on 269 patients with 6 and 12 month follow-up. Primary endpoints were rates of overall death, MACCE, target vessel revascularization, and spontaneous myocardial infarction (MI). Secondary endpoints were overall graft patency and patency of arterial and venous grafts.

RESULTS

There were no significant differences between the FFR-guided and CAG-guided groups in the rates of overall death, MACCE, target vessel revascularization, spontaneous MI and graft patency. Meta-analysis of FARGO and GRAFFITI PRCTs showed that FFR-guided CABG and CAG-guided CABG produced similar clinical outcomes with similar graft patency rates up to a year postoperatively.

CONCLUSION

Currently available PRCTs showes no sufficient evidence to support the use FFR in CABG.

Extracellular Vesicles Enhance the Remodeling of Cell-Free Silk Vascular Scaffolds in Rat Aortae

Vascular tissue engineering is aimed at developing regenerative vascular grafts to restore tissue function by bypassing or replacing defective arterial segments with tubular biodegradable scaffolds. Scaffolds are often combined with stem or progenitor cells to prevent acute thrombosis and initiate scaffold remodeling. However, there are limitations to cell-based technologies regarding safety and clinical translation. Extracellular vesicles (EVs) are nanosized particles released by most cell types, including stem and progenitor cells, that serve to transmit protein and RNA cargo to target cells throughout the body. EVs have been shown to replicate the therapeutic effect of their parent cells; therefore, EVs derived from stem or progenitor cells may serve as a more translatable, cell-free, therapeutic base for vascular scaffolds. Our study aims to determine if EV incorporation provides a positive effect on graft patency and remodeling in vivo. We first assessed the effect of human adipose-derived mesenchymal stem cell (hADMSC) EVs on vascular cells using in vitro bioassays. We then developed an EV-functionalized vascular graft by vacuum-seeding EVs into porous silk-based tubular scaffolds. These constructs were implanted as aortic interposition grafts in Lewis rats, and their remodeling capacity was compared to that observed for hADMSC-seeded and blank (non-seeded) controls. The EV group demonstrated improved patency (100%) compared to the hADMSC (56%) and blank controls (82%) following eight weeks in vivo. The EV group also produced significantly more elastin (126.46%) and collagen (44.59%) compared to the blank group, while the hADMSC group failed to produce significantly more elastin (57.64%) or collagen (11.21%) compared to the blank group. Qualitative staining of the explanted neo-tissue revealed improved endothelium formation, increased smooth muscle cell infiltration, and reduced macrophage numbers in the EV group compared to the controls, which aids in explaining this group's favorable pre-clinical outcomes.

A case report of myocardial ischemia improvement despite early bypass graft occlusion: Efficiency of physiological reassessment

Patients with functional ischemia often do not complain of chest symptoms even in early occlusion after coronary artery bypass grafting (CABG). The clinical evidence indicating the necessity of revascularization for these patients is unclear. A 70-year-old man who underwent 3 stent implant procedures to treat repeated in-stent restenosis to the left anterior descending artery (LAD) felt effort-related chest pain. Coronary angiography revealed that the patient's jailed diagonal had severe stenosis with delay and the LAD had intermediate stenosis. The instantaneous wave-free ratio (iFR) value of the LAD equalled 0.75. The patient underwent sequential CABG, where the left internal mammary artery (LIMA) to the LAD and diagonal artery grafts were performed. Although his effort-related chest pain disappeared, coronary and bypass angiography did not show flow competition in the diagonal branch and early occlusion in the LIMA to LAD graft was confirmed. The physiological assessment of the LAD did not reveal myocardial ischemia (iFR = 0.89 and fractional flow reserve = 0.87). This case highlights the importance of physiological assessment to detect cases of early graft occlusion. Although the LAD was not perfused from the CABG, the iFR value improved dramatically and pharmacological therapy without revascularization was successful for this patient. .

Beyond patency: Functional assessment of adequacy using internal mammary artery grafting to the left anterior descending artery

INTRODUCTION

Arterial graft physiology influences the long-term outcome of coronary artery bypass grafting (CABG). We studied factors that can affect the overall resistance to flow using internal mammary artery grafting to the left anterior descending artery.

METHODS

This was a prospective, nonrandomized observational study of 100 consecutive patients who underwent elective on-pump isolated or combined valve surgery and CABG. Coronary stenoses were assessed using conventional and quantitative coronary angiography assessment. The flow and pulsatility index (PI) of the grafts were assessed by transit-time flowmetry during cardioplegic arrest and at the end of the operation. Fractional polynomials were used to explore linearity, followed by multivariable regression analysis.

RESULTS

Univariate analysis demonstrated higher flows at the end of the operation in patients who had higher flows with the cross-clamp on (P < .001), in males (P = .004), in patients with a low PI at the end of the operation (P = .04), and in patients with a larger size of the recipient artery (P = .005). Multivariable regression analysis showed that the graft flow at the end of the operation was significantly associated with the mean flow with the cross-clamp on (P < .001), sex (P = .003), and PI at the end of the operation (P = .003). Concomitant valve surgery did not influence flows. Male patients had 18 mL/min higher flow.

CONCLUSIONS

The graft flow at the end of the operation can be determined by the flow with the cross-clamp on, the PI with the cross-clamp off and coronary artery. We reported differences in the graft flows between sexes, and for first the time, we introduced the concepts of "adequate flow" and "resistance-to-forward-flow" for patent coronary grafts.

Patency of Individual and Sequential Coronary Artery Bypass in Patients with Ischemic Heart Disease: A Meta-analysis

Objective

To evaluate the patency of individual and sequential coronary artery bypass in patients with ischemic heart disease.

Methods

We searched PubMed, Cochrane Library, Excerpta Medica Database, and ClinicalTrials.gov databases for controlled trials. Endpoints included graft patency, anastomosis patency, occluded rates in left anterior descending (LAD) system and right coronary artery (RCA) system, in-hospital mortality, and follow-up mortality. Pooled risk ratios (RRs) and standardized mean difference (SMD) were used to assess the relative data.

Results

Nine cohorts, including 7100 patients and 1440 grafts under individual or sequential coronary artery bypass. There were no significant differences between individual and sequential coronary artery bypass in the graft patency (RR=0.96; 95% CI=0.91-1.02; P=0.16; I²=87%), anastomosis patency (RR=0.95; 95% CI=0.91-1.00; P=0.05; I²=70%), occluded rate in LAD system (RR=1.03; 95% CI=0.92-1.16; P=0.58; I²=37%), occluded rate in RCA system (RR=1.36; 95% CI=0.72-2.57; P=0.35; I²=95%), in-hospital mortality (RR=1.57; 95% CI=0.92-2.69; P=0.10; I²=0%), and follow-up mortality (RR=0.96; 95% CI=0.36-2.53; P=0.93; I²=0%).

Conclusion

No significant differences on clinical data were observed regarding anastomosis patency, occluded rate in LAD system, occluded rate in RCA system, in-hospital mortality, and follow-up mortality, indicating that the patency of individual and the patency of sequential coronary artery bypass are similar to each other.

Percutaneous coronary intervention versus coronary arterial bypass grafting in patients with multi-vessel coronary revascularization (from the CREDO-Kyoto PCI/CABG registry/cohort-2)

OBJECTIVE

To assess long-term outcomes after percutaneous coronary intervention (PCI) with drug-eluting stent only compared with coronary artery bypass grafting (CABG) in patients with triple-vessel disease.

BACKGROUND

Selection between PCI and CABG is still a clinically relevant issue in the management of patients with multi-vessel coronary artery disease.

METHODS

Among 15,939 patients enrolled in the CREDO-Kyoto PCI/CABG registry/cohort-2, the current study population consisted of 2,193 patients who underwent elective multi-vessel coronary revascularization including left anterior descending coronary artery (LAD) either by PCI with sirolimus-eluting stent (SES) only (N = 945) or CABG (N = 1,248).

RESULTS

The cumulative 5-year incidence of and the adjusted risk for the primary outcome measure (a composite of all-cause death, myocardial infarction [MI], or stroke) were not significantly different between PCI and CABG groups (22.6% vs. 23.0%, p = .40, and HR: 1.13, 95%CI: 0.91-1.40, p = .26). The risk of PCI relative to CABG for all-cause death and stroke was also insignificant (HR: 1.19, 95%CI: 0.92-1.53, p = .19; HR: 0.89, 95%CI: 0.62-1.27, p = .51). The adjusted 5-year risk for MI, hospitalization for heart failure (HF), any coronary revascularization and major bleeding was significantly different between the groups (HR: 1.59, 95%CI: 1.10-2.30, p = .01; HR: 1.49, 95%CI: 1.05-2.11, p = .02; HR: 3.70, 95%CI: 2.91-4.70, p < .0001; HR: 0.18, 95%CI: 0.14-0.22, p < .0001).

CONCLUSIONS

In patients who underwent coronary revascularization for multiple vessels including LAD, PCI using SES as compared with CABG was associated with a comparable 5-year risk for death/MI/stroke as well as for mortality, but with a markedly higher risk for any coronary revascularization.

Percutaneous coronary intervention for distal coronary graft anastomosis le-sions: a case series

BACKGROUND

Management of coronary artery graft failure, especially at the site of a recent distal anastomosis, is a challenging clinical situation, and literature data are scarce.

CASE SERIES

We present a case series of patients with coronary artery bypass graft failure up to six months after surgical revascularization, who were treated with percutaneous coronary intervention at the site of distal graft anastomosis through the graft or the native vessel.

CONCLUSIONS

Percutaneous coronary intervention at distal graft anastomotic lesions is challenging, it can be performed from either the graft or the native vessel, and the angiographic result may not always be optimal. HIPPOKRATIA 2019, 23(2): 87-91.

Post Coronary Artery Bypass Grafting Failure-Don't Always Blame the Blues!!

Long term outcomes following coronary artery bypass grafting are governed by patency of vascular grafts. In this regard, the use of arterial grafts, (preferably the left internal mammary artery) has demonstrated improved survival relative to venous their counterparts. These benefits are a consequence of greater patency of LIMA at 10 years vis-a-vis venous grafts.Howevr, uncommonly there is a possibility of occlusion of LIMA early in the post operative period due to proecudral reasons.We report an unusual case of late occlusion of LIMA after seven years of CABG.

Internal mammary artery graft failure: Clinical features, management, and long-term outcomes

Objective

Data on long-term outcomes after internal mammary artery (IMA) coronary graft failure are scarce. Our objective was to describe the clinical characteristics, management, and prognosis after angiographically confirmed IMA graft failure following coronary revascularization.

Methods

A three-hospital retrospective registry, observational and descriptive, with prospective follow-up of all consecutive cases of IMA graft failure between 2004 and 2014 was conducted. After treatment, clinical and procedural features were compared between those with and without cardiovascular events.

Results

Fifty-seven patients were included (89% male, mean age: 62 years, at surgery) in the registry. Most patients underwent an IMA angioplasty (percutaneous coronary intervention [PCI], 74%). In nine cases, the PCI failed at the graft level, and seven underwent a native vessel revascularization. Native vessel treatment was performed in 20% of the study subjects, all with stents. Finally, medical management was decided in three cases. Events after treatment for IMA graft failure were frequent (50.8%), during a median follow-up of 7.5 years. Acute presentation (hazard ratio_MACE = 1.35; 95% confidence interval (CI): 1.12–3.00, p < 0.01), age of the patient (hazard ratio_MACE = 1.85, 95% CI: 1.17–2.11, p < 0.01), presence of diabetes mellitus (hazard ratio_MACE = 2.75, 95% CI: 1.13–6.69, p = 0.02), and the management modality used (IMA-simple angioplasty VS IMA-stenting: hazard ratio_MACE = 5.5, 95% CI: 1.40–21.15, p = 0.01) displayed prognostic relevance on multivariate analysis. All-cause mortality occurred in 21.1% and presentation as infarction (hazard ratio_DEATH = 1.05, 95% CI: 1.01–2.17, p = 0.01), age (hazard ratio_DEATH = 9.08, 95% CI: 2.52–32.69, p < 0.01), and left ventricular ejection fraction (hazard ratio_DEATH = 3.68, 95% CI: 1.65–8.18, p < 0.01) were independent predictors of the same.

Conclusions

In this long-term registry, most patients presented with an acute condition (myocardial infarction, progressive angina) within 12 months after surgery. Acute presentation, age, diabetes mellitus, reduced left ventricular ejection fraction, IMA graft failure segment affected, and the management strategy were related with long-term prognosis.

Intraoperative transit-time flowmetry in patients undergoing coronary surgery to determine relationships between graft flow and patency and prior coronary interventions and flow demand: a retrospective study

Background

The aim of this study was to delineate impacts of percutaneous coronary intervention (PCI), flow demand, and status of myocardium on graft flow.

Methods

We retrospectively assessed 736 individual coronary artery bypass grafts that had been created as the sole bypass graft for a vascular region in 405 patients. The grafts comprised 334 internal thoracic artery (ITA) to left anterior descending (LAD), 129 ITA and 65 saphenous vein grafts (SVG) to left circumflex (LCX), and 142 gastroepiploic artery (GEA) and 66 SVG to right coronary artery (RCA). Minimal luminal diameter, size of revascularized area, history of myocardial infarction, and PCI in the relevant area were examined to determine whether these factors are associated with flow insufficiency (FI), which was defined as ≤ 20 mL/min.

Results

FI developed in 123/736 grafts (16.7%) and correlated significantly with stenosis in the distal portion (23.0% vs. 12.8%, p = 0.0003). Prior myocardial infarction significantly correlated with FI in GEA–RCA (p = 0.002) and ITA–LCX grafts (p = 0.04). There was a history of PCI to the LAD (PCI group) in 54 ITA to LAD bypass grafts (16.2%), whereas the remaining 280 had no history of PCI to the LAD (no-PCI group). Graft flow was significantly greater in the no-PCI than in the PCI group (53 ± 29 vs. 42 ± 27; p = 0.006). The incidences of FI and graft failure were significantly higher in the PCI than the no-PCI group (22.2%, vs. 8.2%; p = 0.003; 9.2% vs. 1.8%; p = 0.003, respectively).

Conclusions

Prior PCI has a negative impact on graft flow. The influences of small revascularized area, myocardial infarction, and PCI are greater, necessitating consideration of factors associated with flow demand or microvasculature when planning revascularization.

Coronary artery bypass graft surgery complications: A review for emergency clinicians

INTRODUCTION

Coronary artery bypass graft (CABG) surgery remains a high-risk procedure, and many patients require emergency department (ED) management for complications after surgery.

OBJECTIVE

This narrative review provides an evidence-based summary of the current data for the emergency medicine evaluation and management of post-CABG surgery complications.

DISCUSSION

While there has been a recent decline in all cardiac revascularization procedures, there remains over 200,000 CABG surgeries performed in the United States annually, with up to 14% of these patients presenting to the ED within 30 days of discharge with post-operative complications. Risk factors for perioperative mortality and morbidity after CABG surgery can be divided into three categories: patient characteristics, clinician characteristics, and postoperative factors. Emergency physicians will be faced with several postoperative complications, including sternal wound infections, pneumonia, thromboembolic phenomena, graft failure, atrial fibrillation, pulmonary hypertension, pericardial effusion, strokes, renal injury, gastrointestinal insults, and hemodynamic instability. Critical patients should be evaluated in the resuscitation bay, and consultation with the primary surgical team is needed, which improves patient outcomes. This review provides several guiding principles for management of acute complications. Understanding these complications and an approach to the management of hemodynamic instability is essential to optimizing patient care.

CONCLUSIONS

Postoperative complications of CABG surgery can result in significant morbidity and mortality. Physicians must rapidly diagnose these conditions while evaluating for other diseases. Early surgical consultation is imperative, as is optimizing the patient's hemodynamics, including preload, heart rate, cardiac rhythm, contractility, and afterload.