Spasm in Arterial Grafts in Coronary Artery Bypass Grafting Surgery

A Rare Case of Nitroglycerin Resistant Coronary Arterial Vasospasm During Coronary Artery Bypass Surgery

BACKGROUND

Coronary artery vasospasm following coronary artery bypass grafting (CABG) is a rare but potentially life-threatening complication that can lead to myocardial ischemia, arrhythmias, and cardiogenic shock. Nitroglycerin-resistant vasospasm, particularly involving the left main coronary artery (LMCA), poses significant diagnostic and therapeutic challenges.

CASE PRESENTATION

We report the case of a 47-year-old female with a history of hypertension, hyperlipidemia, and ADHD on dextroamphetamine-amphetamine, who presented with chest pain and was found to have a suspected severe LMCA lesion. Coronary angiography revealed a 95% LMCA stenosis that was unresponsive to intracoronary nitroglycerin, raising concern for catheter-induced vasospasm versus true stenosis. The patient underwent urgent CABG. Intraoperatively and postoperatively, she experienced recurrent, diffuse coronary vasospasm refractory to nitroglycerin, necessitating multiple interventions including mechanical circulatory support with intra-aortic balloon pump and percutaneous ventricular assist device. Coronary angiography confirmed severe diffuse coronary and peripheral vasospasm. The patient was managed with intravenous vasodilators, vasopressors, and supportive care, and eventually recovered with restoration of cardiac function and discharge to cardiac rehabilitation.

DISCUSSION

This case underscores the difficulty in differentiating vasospasm from true atherosclerotic disease in the LMCA, the potential for nitroglycerin resistance, and the risk of severe complications during CABG. The use of adjunctive imaging modalities, vasodilators beyond nitroglycerin, and early mechanical circulatory support may be critical in managing such complex cases.

CONCLUSION

Nitroglycerin-resistant coronary vasospasm, especially in the LMCA, can mimic fixed stenosis and lead to inappropriate surgical intervention and life-threatening complications. A multidisciplinary, imaging-guided approach is essential for accurate diagnosis and optimal management.

Sequential Grafting of the Left Internal Thoracic Artery to the Left Anterior Descending Artery and Graft Failure

BACKGROUND

There is concern that left internal thoracic artery (LITA)-to diagonal (D)-to left anterior descending artery (LAD) grafts may be more susceptible to failure compared with single LITA-LAD grafts.

METHODS

Pooled individual patient data from 8 clinical trials with systematic graft imaging were analyzed to assess the incidence of sequential LITA-D-LAD vs single LITA-LAD grafts. Mixed-effects multivariable logistic regression, adjusting for patient characteristics and clustering within trials, was used.

RESULTS

Of 3969 patients with LITA-LAD grafts, 283 patients (7.1%) received sequential LITA-D-LAD grafts. Patients with sequential LITA-D-LAD grafts were older (66 vs 65 years, P = .009) and more often men (88% vs 83%, P = .03). Overall, graft failure occurred in 9.3% of patients with LITA-LAD grafts, with more graft failure occurring in single (9.5%) than in sequential LITA-D-LAD grafts (6.4%, P = .08) at a median time to imaging of 1.0 years (interquartile range, 1.0-1.1 years). After multivariable adjustment, sequential LITA-D-LAD grafting was not associated with graft failure (adjusted odds ratio, 1.22; 95% CI, 0.68-2.18; P = .55). There was no difference between groups in mortality (2.8% vs 5.3%, P = .06), myocardial infarction (1.4% vs 1.6%, P = .90), revascularization (4.5% vs 7.3%, P = .08), or stroke (1.7% vs 1.2%, P = .40).

CONCLUSIONS

In selected patients, LITA-D-LAD grafting was not associated with higher risk of graft failure or adverse clinical events at 1 year.

Surgical Revascularization Decisions in Ischemia and Heart Failure

Coronary artery bypass grafting is the major modality of coronary revascularization in patients with ischemic cardiomyopathy as it provides surgical collateralization of the coronary bed protecting the functional myocardium. Myocardial viability testing does not have an established role in the surgical evaluation. Concomitant surgical ventricular restoration does not improve symptoms or survival, though patients with large aneurysms and significant reduction in ventricular size could benefit. Correction of functional mitral regurgitation does not improve survival, and severe functional mitral regurgitation should be addressed via mitral valve replacement. Temporary mechanical circulatory support can be used as a bridge to recovery.

Reducing vasospasm of vein and arterial conduits used in coronary artery bypass surgery: are solutions the solution or is preserved perivascular fat the answer?

The three main conduits used for myocardial revascularization in patients with coronary artery disease (CAD) are the internal thoracic artery (ITA), radial artery (RA) and saphenous vein (SV). In coronary artery bypass grafting (CABG) conduits may be harvested with perivascular adipose tissue (PVAT) intact (pedicled) or removed (skeletonized). Various studies have shown that the patency rate of these bypass grafts may be affected by the preservation or removal of PVAT. Vasospasm is often encountered at harvesting, a condition that has both immediate and long term effects on graft performance. During surgery a variety of antispastic solutions are routinely used on conduits that have anti-contractile and/or vasorelaxant actions. Spasm may be abolished or reduced when PVAT is left intact at harvesting and this is particularly the case for the SV. The protective properties of PVAT are multifactorial, ranging from its mechanical properties in supporting the graft after implantation to the beneficial effect of adipocyte-derived factors. This review aims to outline the possible mechanisms through which preserved PVAT could alleviate vasospasm and improve conduit performance in CABG. Moreover, since preservation of PVAT reduces spasm at and after surgery this review also considers whether antispastic solutions are needed if conduits are harvested with PVAT intact.

Intra-operative and post-operative management of conduits for coronary artery bypass grafting: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Surgery and the European Association for Cardio-Thoracic Surgery Coronary Task Force

The structural and functional integrity of conduits used for coronary artery bypass grafting is critical for graft patency. Disruption of endothelial integrity and endothelial dysfunction are incurred during conduit harvesting subsequent to mechanical or thermal injury and during conduit storage prior to grafting, leading to acute thrombosis and early graft failure. Late graft failure, in particular that of vein grafts, is precipitated by progressive atherogenesis. Intra-operative management includes appropriate selection of conduit-specific harvesting techniques and storage solutions. Arterial grafts are prone to vasospasm subsequent to surgical manipulation, and application of intra-operative vasodilatory protocols is critical. Post-operative management includes continuation of oral vasodilator therapy and selection of antithrombotic and lipid-lowering agents to attenuate atherosclerotic disease progression in conduits. In this review, the scientific evidence underlying the key aspects of intra- and post-operative management of conduits for coronary artery bypass grafting is examined. Clinical consensus statements for best clinical practice are provided, and areas requiring further research are highlighted.

Impact of Norepinephrine Use on Free Flap Survival in Breast Reconstructive Microsurgery

OBJECTIVE

The optimal method for maintaining intraoperative blood pressure during microsurgical procedures remains controversial. While intravenous fluid administration is essential, overfilling can lead to complications. Vasopressor agents are used cautiously due to their vasoconstrictive effects, which could potentially lead to flap failure. Numerous studies have explored the possible link between amine administration and free flap failure, yielding inconsistent results. This study aims to determine whether intraoperative norepinephrine administration increases the flap failure rate in microsurgical breast reconstructions.

METHODS

All women (n = 335) who underwent breast reconstruction using DIEP or PAP flaps (n = 400) in 2018 and 2022 in the Plastic Surgery Department of Georges-Pompidou European Hospital (Paris, France) were included in the study. These patients were classified into two groups based on the intraoperative administration of norepinephrine: the N+ group (50 patients) and the N- group (285 patients). Norepinephrine was administered when systolic blood pressure fell below 90 mmHg or mean arterial pressure (MAP) dropped below 65 mmHg, following fluid resuscitation in 2018, or without prior fluid loading in 2022. The primary endpoint was total flap loss. Secondary endpoints included arterial and venous thrombosis and the need for revision surgeries.

RESULTS

Norepinephrine administration significantly increased the risk of total flap loss in DIEP and PAP flap surgeries (p < 0.001). It also heightened the risk of arterial thrombosis (p = 0.002) and venous thrombosis (p = 0.04), and led to a greater number of revision surgeries (p < 0.001). Subgroup analysis indicated that PAP flaps are more sensitive to norepinephrine compared to DIEP flaps.

CONCLUSIONS

Our study suggests that the intraoperative administration of any dose of norepinephrine is associated with an increased risk of flap failure in breast reconstructive microsurgery using DIEP and PAP flaps.

Intra-operative and post-operative management of conduits for coronary artery bypass grafting: a clinical consensus statement of the European Society of Cardiology Working Group on Cardiovascular Surgery and the European Association for Cardio-Thoracic Surgery Coronary Task Force

The structural and functional integrity of conduits used for coronary artery bypass grafting is critical for graft patency. Disruption of endothelial integrity and endothelial dysfunction are incurred during conduit harvesting subsequent to mechanical or thermal injury and during conduit storage prior to grafting, leading to acute thrombosis and early graft failure. Late graft failure, in particular that of vein grafts, is precipitated by progressive atherogenesis. Intra-operative management includes appropriate selection of conduit-specific harvesting techniques and storage solutions. Arterial grafts are prone to vasospasm subsequent to surgical manipulation, and application of intra-operative vasodilatory protocols is critical. Post-operative management includes continuation of oral vasodilator therapy and selection of antithrombotic and lipid-lowering agents to attenuate atherosclerotic disease progression in conduits. In this review, the scientific evidence underlying the key aspects of intra- and post-operative management of conduits for coronary artery bypass grafting is examined. Clinical consensus statements for best clinical practice are provided, and areas requiring further research are highlighted.

Consensus statement-graft treatment in cardiovascular bypass graft surgery

Coronary artery bypass grafting (CABG) is and continues to be the preferred revascularization strategy in patients with multivessel disease. Graft selection has been shown to influence the outcomes following CABG. During the last almost 60 years saphenous vein grafts (SVG) together with the internal mammary artery have become the standard of care for patients undergoing CABG surgery. While there is little doubt about the benefits, the patency rates are constantly under debate. Despite its acknowledged limitations in terms of long-term patency due to intimal hyperplasia, the saphenous vein is still the most often used graft. Although reendothelialization occurs early postoperatively, the process of intimal hyperplasia remains irreversible. This is due in part to the persistence of high shear forces, the chronic localized inflammatory response, and the partial dysfunctionality of the regenerated endothelium. "No-Touch" harvesting techniques, specific storage solutions, pressure controlled graft flushing and external stenting are important and established methods aiming to overcome the process of intimal hyperplasia at different time levels. Still despite the known evidence these methods are not standard everywhere. The use of arterial grafts is another strategy to address the inferior SVG patency rates and to perform CABG with total arterial revascularization. Composite grafting, pharmacological agents as well as latest minimal invasive techniques aim in the same direction. To give guide and set standards all graft related topics for CABG are presented in this expert opinion document on graft treatment.

Proper Treatment and Management of Postcardiotomy Refractory Vasospasm

We present here a unique case in which a 63-year-old man developed diffuse coronary vasospasm on postoperative day (POD) 1 following uneventful aortic valve replacement, replacement of ascending aorta, and coronary artery bypass. Subsequent emergent coronary angiogram demonstrated diffuse native coronary artery vasospasm that was only transiently responsive to intracardiac nitroglycerin, resulting in persistent cardiogenic shock and severe biventricular dysfunction. The patient was, thus, placed on femoral-femoral venoarterial (VA) extracorporeal membrane oxygenation (ECMO) with Impella support. This strategy allowed the weaning of vasopressors and enabled the resolution of the vasospasm. The patient was ultimately discharged on POD 17 without further complications. This case demonstrates our management strategy to provide life-saving support for patients facing postcardiac surgery refractory vasospasm.

Coronary artery bypass grafting in left ventricular dysfunction: when and how

PURPOSE OF REVIEW

The surgical management of patients undergoing coronary artery bypass grafting (CABG) with low ejection fraction presents unique challenges that require meticulous attention to details and good surgical technique and judgement. This review details the latest evidence and best practices in the care of such patients.

RECENT FINDINGS

CABG in patients with low ejection fraction carries a significant risk of perioperative mortality and morbidity related to the development of postcardiotomy shock. Preoperative optimization with pharmacological or mechanical support is required, especially in patients with cardiogenic shock. Rapid and complete revascularization is what CABG surgeons aim to achieve. Multiple arterial revascularization should be reserved to selected patients. Off-pump CABG, on-pump breathing heart CABG, and new cardioplegic solutions remain of uncertain benefit compared with traditional CABG.

SUMMARY

Tremendous advancements in CABG allowed surgeons to offer revascularization to patients with severe left ventricular dysfunction and multivessel disease with acceptable risk. Despite that, there is a lack of comprehensive and robust studies particularly on long-term outcomes. Individualized patient assessment and a heart team approach should be used to determine the optimal surgical strategy for each patient.

To reverse or not to reverse the radial artery in coronary artery bypass graft surgery? Histopathologic concerns and media thickness

Background and aims

Radial artery (RA) is a popular coronary artery bypass grafting (CABG) conduit. The challenging issue is vasospasm. A few studies are available on histopathological differences between RA's proximal and distal ends. This study aims to compare histopathological features of the proximal and distal end of RA to find the best technique for anastomosis.

Methods

In this matched case-control study, 80 patients were included who underwent CABG and used RA as a graft. Ten subjects were excluded. RA was harvested by open technique, and a cocktail of Papaverine, Verapamil, and Nitroglycerine was frequently applied topically. One centimeter of proximal and distal ends of the RA was evaluated considering its Histopathology. Clinical signs of RA graft vasospasm were monitored from harvesting until the post-operative period. Intima, media, and intima-media thickness (IMT) index were compared between the two cohorts.

Results

Vasospasm occurred in 1.41% of patients. The mean intimal thickness in the proximal and distal ends were, respectively, 0.20 (standard deviation [SD] 0.17 mm) vs. 0.31 (SD 0.18 mm) (p < 0.001). The mean media thickness in the distal end was higher than the proximal end (0.98 [SD 0.36] vs. 1.09 [SD 0.37], p = 0.004). IMT index of the proximal and distal ends showed a statistically significant difference (0.22 [SD 0.17] vs. 0.31 [SD 0.19]) (p < 0.001).

Conclusion

The overall incidence rate of vasospasm in our study is comparable with other studies using the same cocktail. Proximal RA has a relatively lower medial thickness compared to the distal part, which may induce less vasospasm in CABG patients.

Effect of Nicorandil, Diltiazem, or Isosorbide Mononitrate for Oral Antispastic Therapy After Coronary Artery Bypass Grafting Using Radial Artery Grafts-A Pilot Randomized Controlled Trial (ASRAB-Pilot): Rationale and Study Protocol

INTRODUCTION

The current evidence for chronic oral antispastic medication use after coronary artery bypass grafting using radial artery grafts (RA-CABG) is controversial. Calcium channel blockers, such as diltiazem, are the most commonly used antispastic medications after RA-CABG; other options include nitrates and nicorandil, but to date no sufficiently powered randomized controlled trials have been conducted to compare their efficacy.

METHODS

This is a single-center, open-label, parallel three-arm, pilot randomized controlled trial. Patients without contraindications to any study medications and who successfully underwent RA-CABG surgery will be consecutively screened. Eligible patients will be randomized in a ratio of 1:1:1 (a total of 150 patients, 50 per arm) to receive nicorandil 5 mg orally thrice daily, diltiazem 180 mg orally once daily, or isosorbide mononitrate 50 mg orally once daily for 24 weeks. The primary outcomes are RA graft failure at week 1 and week 24. The secondary outcomes include major adverse cardiovascular event (MACE, a composite of all-cause death, myocardial infarction, stroke, and unplanned revascularization) and angina recurrence. The safety outcomes include hypotension occurrence, withdrawal of renin angiotensin aldosterone system inhibitors, serious adverse events, and other concerned adverse events within 24 weeks.

CONCLUSION

This pilot trial will compare the preliminary effects of nicorandil, diltiazem, and isosorbide mononitrate on angiographic and clinical outcomes in patients who have undergone RA-CABG. Recruitment began in June 2020, and the estimated primary completion date is early 2023. Results of this study will provide much needed information for design of large confirmatory trials on the effectiveness of oral antispastic medications after RA-CABG.

Antispastic Effect of Fasudil and Cocktail of Fasudil and Nitroglycerin in Internal Thoracic Artery

BACKGROUND

Spasm of arterial grafts in coronary artery bypass grafting is a clinical problem and can occasionally be lethal. Perioperative spasm in the internal thoracic artery (ITA) and coronary arteries occurs in 0.43% of patients. This study aimed to investigate the antispastic effect of a RhoA/Rho-kinase (Rho-associated coiled-coil-containing protein kinase [ROCK]) inhibitor (fasudil) with and without nitroglycerin in combination in the ITA.

METHODS

Isolated human ITA rings taken from 68 patients who were undergoing coronary bypass were studied in a myograph. Cumulative concentration-relaxation curves for fasudil (-9 to -3.5 log M) were established in the ITA, which was precontracted with potassium chloride or U46619. The inhibitory effect of fasudil (-6.3 or -5.3 log M) or fasudil in combination with nitroglycerin were also tested. The ROCK2 protein was measured by Western blot.

RESULTS

Fasudil caused similar relaxation in ITA rings contracted by potassium chloride or U46619. Pretreatment with -5.3 log M fasudil significantly depressed contraction induced by potassium chloride (P = .004 vs control; P = .017 vs -6.3 log M) and U46619 (P = .010 vs control; P = .041 vs. -6.3 log M). Fasudil in combination with nitroglycerin had more effect and more rapid and sustained relaxation than either vasodilator alone. Fasudil caused a decrease of ROCK2 protein content (P = .014).

CONCLUSIONS

Fasudil fully relaxes some vasoconstrictor-induced contraction and decreases ROCK2 protein content in the ITA. The combination of fasudil and nitroglycerin has a superior effect than either vasodilator alone. The new cocktail solution composed of fasudil and nitroglycerin (pH 7.4) has effective antispastic action and may prove to be a new antispastic method for arterial conduits during coronary bypass surgery.

Diffuse Coronary Vasospasm After Mitral Valve Replacement, Maze Procedure, and Tricuspid Valve Repair

Coronary vasospasm is a known complication after coronary artery bypass grafting surgery but has rarely been described in non-coronary cardiac operations. We report the case of a 51-year-old male with nonischemic cardiomyopathy and paroxysmal atrial fibrillation. He presented with severe mitral and tricuspid regurgitation and was taken for mitral valve replacement, tricuspid valve repair, and Maze procedure. Postoperative emergent coronary angiography demonstrated diffuse coronary vasospasm. Injection of intracoronary nitroglycerin led to clinical and angiographic improvement. This demonstrates the possibility of coronary vasospasm following mitral valve replacement and effective treatment with intracoronary administration of vasodilating agents.

The Effects of Vasodilation Induced by Brachial Plexus Block on the Development of Postoperative Thrombosis of the Arteriovenous Access in Patients with End-Stage Renal Disease: A Retrospective Study

Although brachial plexus block (BPB)-induced vasodilation reduces the incidence of arteriovenous access (AC) thrombosis, BPB cannot completely prevent its development. Therefore, we retrospectively investigated the factors affecting BPB-induced vasodilation and their effects on AC thrombosis development. Ninety-five patients undergoing AC surgery under BPB were analyzed. Vessel diameters were measured before and 20 min after BPB. The surgery abandoned before the BPB placement was performed when the BPB-induced increases in vessel diameters met its indications. Complete occlusive access thrombosis (COAT) was defined as loss of pulse, thrill, or bruit. Fourteen patients (14.7%) developed COAT. The outflow vein was more dilated by BPB than the inflow artery (0.6 versus 0.1 mm in median, p < 0.001). The original surgery plan was changed for seven patients (7.4%). Diabetes mellitus (DM) and ischemic heart disease (IHD) decreased the extent of increases in the inflow artery by -0.183 mm (95% confidence interval [CI] [-0.301, -0.065], p = 0.003) and outflow vein diameters by -0.402 mm (95% CI [-0.781, -0.024], p = 0.038), respectively. However, DM, IHD, and changes in the vessel diameters had insignificant effects on the development of COAT. In conclusion, although DM and IHD attenuate the vasodilating effects of BPB, they do not contribute to the development of COAT.

Perioperative diltiazem therapy was not associated with improved perioperative and long-term outcomes in patients undergoing on-pump coronary artery bypass grafting

Background

Diltiazem has been used during the perioperative period in patients undergoing coronary artery bypass grafting (CABG) to prevent arterial graft spasm. However, its long-term outcome effects remain unclear.

Methods

Patient records obtained from the Society of Thoracic Surgeons and the Geisinger Clinic electronic health records between October 2008 and October 2018 were screened. Adult patients who had isolated CABG with cardiopulmonary bypass were included. Cohorts of patients who received diltiazem (DILT) and those who did not (non-DILT) were matched by propensity scores based on age, gender, surgical year, Society of Thoracic Surgeons mortality and morbidity scores, and number of arterial grafts. Incidence rate ratios (IRRs) were estimated for DILT vs non-DILT on short-term adverse outcomes. Long-term survival over time was compared between DILT vs non-DILT using Kaplan-Meier curves.

Results

Among the 1004 patients included in the analyses, IRRs for the DILT group relative to the non-DILT group were: 30-day all-cause mortality, IRR: 2.33, 95% confidence interval (CI): 0.91-5.96, P=0.07; postoperative myocardial ischaemia, IRR: 1.10, 95% CI: 0.60-2.02, P=0.75; new onset atrial fibrillation, IRR: 1.06, 95% CI: 0.78-1.43, P=0.73; stroke/transient ischaemic attack, IRR: 0.76, 95% CI: 0.17-3.38, P=0.71. For long-term survival, Kaplan-Meier curves stratified by diltiazem revealed no differences in survival rates between DILT and non-DILT groups.

Conclusion

For patients undergoing on-pump CABG, perioperative diltiazem therapy did not show significant short- or long-term outcome advantages over those who did not receive diltiazem.

Impact of acute dynamic exercise and arterial shear rate modification on radial artery low-flow mediated constriction in young men

Purpose

Leg cycling exercise acutely augments radial artery low-flow mediated constriction (L-FMC). Herein, we sought to determine whether this is associated with exercise-induced changes in arterial shear rate (SR).

Methods

Ten healthy and recreationally active young men (23 ± 2 years) participated in 30 min of incremental leg cycling exercise (50, 100, 150 Watts). Trials were repeated with (Exercise + WC) and without (Exercise) the use of a wrist cuff (75 mmHg) placed distal to the radial artery to increase local retrograde SR while reducing mean and anterograde SR. Radial artery characteristics were measured throughout the trial, and L-FMC and flow mediated dilatation (FMD) were assessed before and acutely (~ 10 min) after leg cycling.

Results

Exercise increased radial artery mean and anterograde SR, along with radial artery diameter, velocity, blood flow and conductance (P < 0.05). Exercise + WC attenuated the exercise-induced increase in mean and anterograde SR (P > 0.05) but also increased retrograde SR (P < 0.05). In addition, increases in radial artery blood flow and diameter were reduced during Exercise + WC (Exercise + WC vs. Exercise, P < 0.05). After Exercise, L-FMC was augmented (− 4.4 ± 1.4 vs. − 13.1 ± 1.6%, P < 0.05), compared to no change in L-FMC after Exercise + WC (− 5.2 ± 2.0 vs. − 3.0 ± 1.6%, P > 0.05). In contrast, no change in FMD was observed in either Exercise or Exercise + WC trials (P > 0.05).

Conclusions

These findings indicate that increases in L-FMC following exercise are abolished by the prevention of increases radial artery diameter, mean and anterograde SR, and by elevation of retrograde SR, during exercise in young men.

Perioperative coronary artery spasm after off-pump coronary artery bypass grafting in the non-manipulated coronary artery

BACKGROUND

Perioperative coronary artery spasm (CAS) following coronary artery bypass grafting (CABG) is a severe or lethal condition that is rarely reported. In addition, rare cases with CAS following CABG in the non-manipulated coronary artery are angiographically documented in the perioperative period. We aimed to report our experiences on the diagnosis and treatment of a case with CAS following off-pump CABG in the non-manipulated coronary artery.

METHODS

A 57-year old male with coronary heart disease and unstable angina willing to undergo CABG was admitted to our department. CABG was recommended as he showed 90% stenosis in distal left anterior descending artery, 90% stenosis in intermediate branch, 90% stenosis in left circumflex coronary artery, as well as 50% stenosis in proximal right coronary artery (RCA).

RESULTS

After CABG, the patient showed Adams-Stokes syndrome and ST-segment elevation. Then CPR was conducted and coronary angiography indicated perioperative CAS in the non-manipulated posterior descending artery. For the treatment, the patient received nitroglycerin injection into the coronary artery by catheter and pumping of diltiazem. Finally, the patient was discharged on day 7 after surgery. A comprehensive literature search was conducted to summarize the studies focused on the diagnosis and treatment of such condition, which indicated that all of the CAS cases occurred in the manipulated vessels, except one study showing CAS in the untouched native coronary artery which was similar with our case.

CONCLUSIONS

Perioperative CAS in the non-manipulated coronary artery following CABG is a severe or lethal condition that is rarely reported, which deserves close attention by the clinicians in clinical practice.

Comparative study on the effect of aspirin, TP receptor antagonist and TxA2 synthase inhibitor on the vascular tone of human saphenous vein and internal mammary artery

AIMS

Thromboxane (TxA₂) is synthesized from arachidonic acid (AA) via thromboxane synthase (TxS) enzyme and induces vasoconstriction via TP receptor. Our aim is to compare the effects of aspirin, TxS inhibitor and TP receptor antagonist on vascular reactivity of bypass grafts (saphenous vein and internal mammary artery).

MAIN METHODS

Using isolated organ bath, saphenous vein and internal mammary artery preparations were incubated with TP receptor antagonist, TxS inhibitor, aspirin, IP or EP4 receptor antagonist. Then prostaglandin (PG)E₂, PGF_2α, phenylephrine and AA were administered in concentration-dependent manner. The expression of prostanoid receptor and PGI₂ synthase (PGIS) enzyme was determined by Western Blot.

KEY FINDINGS

TP receptor antagonist inhibited the contraction induced by PGE₂, PGF_2α, and AA but not that induced by phenylephrine in both types of vessels. Aspirin increased phenylephrine-induced contraction only in internal mammary artery and decreased AA-induced contraction in saphenous vein. TxS inhibitor decreased both PGE₂ and AA-induced contraction in both types of vessels. This decrease was reversed by co-incubation of TxS inhibitor and IP/EP4 receptor antagonists. The expressions of EP3 receptor and PGIS enzyme were greater in internal mammary artery compared to saphenous vein while IP and TP receptors expressed at similar levels.

SIGNIFICANCE

TP receptor antagonist and TxS inhibitor are more effective to reduce contraction induced by different spasmogens in comparison to aspirin. Our results suggest that TP receptor antagonist and TxS inhibitor might have an advantage over aspirin due to their preventive effect on increased vascular reactivity observed in post-operative period of coronary artery bypass grafting.

Coronary artery bypass grafting in low ejection fraction: state of the art

PURPOSE OF REVIEW

As the number of patients with reduced ejection fraction secondary to ischemic cardiomyopathy (ICM) increases, coronary artery bypass grafting is being used with increasing frequency. In this review, we summarize the different operative considerations in this vulnerable patient population.

RECENT FINDINGS

Preoperative optimization with mechanical circulatory support devices, especially in the setting of hemodynamic instability, can reduce perioperative morbidity and mortality. The advantage of advanced techniques, such as off-pump CABG and multiple arterial grafting remains unclear. Concomitant procedures, such as ablation for atrial fibrillation remain important considerations that should be tailored to the individual patients risk profile.

SUMMARY

Despite improvements in perioperative care of patients undergoing CABG, patients with a reduced ejection fraction remain at elevated risk of major morbidity and mortality. Preoperative optimization and careful selection of intraoperative techniques can lead to improved outcomes.

The Effect of Very Low Concentrations of Ethanol on Microvascular Artery and Vein Anastomosis: An Experimental Study

OBJECTIVES

This study investigated the effect of very low concentrations of ethanol on artery and vein anastomosis. Also, it was aimed to determine the appropriate ethanol concentration to be used in vasospasm.

METHODS

Rats were divided into five groups of eight rats, each group, as follows: Group i: saline; Group ii: 2.5% ethanol; Group iii: 5% ethanol; Group IV: 7.5% ethanol; and Group V: 10% ethanol. During the femoral artery and vein anastomosis, 1ml of the agent was used for irrigation in each group. Vessel diameters were measured before the anastomosis, at the fifth and 15th minutes, and the third week after the anastomosis. Histopathological samples were taken in the third week.

RESULTS

In Groups ii and iii, the mean vessel diameters were found to increase 15th minute. Also observed was an increase in mean vessel diameter that continued in the third week. Although acute vasodilation was detected in Groups IV and V, arterial and venous thrombosis was observed in the third week. Intima and media thickness decreased in Group ii, while it increased in Group iii. Perivascular inflammation and fibrosis increased as the ethanol concentration increased.

CONCLUSION

2.5% ethanol causes acute and prolonged vasodilation and does not cause endothelial cell damage, perivascular inflammation, and fibrosis. 2.5% ethanol will be a powerful alternative use in many situations that occur with vasospasm.

Comparative study of coronary artery bypass graft materials: reduced contraction and ADMA levels in internal mammary artery versus saphenous vein

BACKGROUND

Vasospasm and atherosclerosis due to low endothelial capacity are the most important causes of coronary artery bypass graft failure observed in internal mammary artery (IMA) and saphenous vein (SV). Vasospasm can be mimicked in in vitro studies by inducing vasoconstriction of graft materials. In the present study, we aimed to compare the vascular contraction induced by several spasmogens including prostaglandin E2 (PGE2), prostaglandin F2 alpha (PGF2α), phenylephrine (PE), leukotriene C4 (LTC4), LTD4, potassium chloride (KCl), and arachidonic acid between IMA and SV preparations. Furthermore, endothelial capacity, nitrite and asymmetric dimethylarginine (ADMA) levels were compared between two grafts.

METHODS

By using organ bath, contractile responses induced by different spasmogens were compared between IMA and SV preparations derived from patients underwent coronary artery bypass surgery (n=35). The endothelial capacity was determined by acetylcholine (ACh) -induced relaxation in PE-precontracted vessels. Nitrite and ADMA levels were measured in organ culture supernatant of IMA and SV preparations.

RESULTS

Contractile responses induced by PGE2, PGF2α, PE, LTC4, LTD4, KCl and arachidonic acid were significantly lower in IMA preparations versus SV preparations. ACh-induced relaxation was significantly more prominent in IMA than SV preparations. Nitrite levels were greater and ADMA levels were lower in IMA versus SV preparations.

CONCLUSIONS

IMA has reduced capacity to constrict to several vasoconstrictor agents. Furthermore, IMA has greater endothelial capacity associated with higher nitrite levels and lower ADMA levels. Our results support the greater patency rate observed in IMA versus SV preparations.

Reopening of the occluded saphenous vein composite grafts after coronary artery bypass grafting

BACKGROUND

We have observed reopening of the occluded "no-touch" saphenous vein (NT SV) composite grafts on follow-up angiograms in patients who underwent coronary artery bypass graftings (CABGs).

METHODS

Between 2008 and 2018, 1283 patients received NT SV conduits without or with surrounding pedicle tissue as composite grafts based on the in situ left internal thoracic artery (ITA) for CABG and underwent early postoperative angiographies. Among the 1283 patients, 53 patients showed 55 occluded SV conduit anastomoses, and 46 patients who had 48 occluded SV anastomoses were re-evaluated by 1-year postoperative angiographies.

RESULTS

Early postoperative angiographies in 1283 patients demonstrated overall occlusion rates of 1.2% (56/4518); occlusion rates of the ITA and SV were 0.08% (1/1259) and 1.7% (55/3260), respectively. One-year angiograms demonstrated that 14 occluded SV anastomoses (29.2% [14/48 occluded SV]) of 14 patients became patent. Reopening of occluded SV conduits occurred more frequently in NT SV with pedicle tissue than in NT SV without pedicle tissue (45.0% [9/20] vs. 17.9% [5/28]; p = .057). When we examined the preoperative and 1-year postoperative angiograms, reopening of the occluded SV conduits was not related with progression (p = .258) or preoperative reversibility score (p = .115) of native target coronary artery disease.

CONCLUSIONS

More than a quarter of the occluded SV composite grafts on early postoperative angiograms were patent in the 1-year angiograms. The reopening rates were higher in patients who had received NT SV conduits with pedicle tissue than those who had received NT SV conduits without pedicle tissue.

How to build a multi-arterial coronary artery bypass programme: a stepwise approach

Observational evidence shows that the use of multiple arterial grafts (MAG) is associated with longer postoperative survival and improved clinical outcomes. The current European Society of Cardiology/European Association for Cardio-Thoracic Surgery Guidelines on myocardial revascularization recommend the use of MAG in appropriate patients. However, a significant volume-to-outcome relationship exists for MAG, and lack of sufficient experience is associated with increased operative risk. A stepwise approach to building experience with MAG allows successful implementation of this technique into routine coronary surgery practice.

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.

Combined effect of left stellate ganglion blockade and topical administration of papaverine on left internal thoracic artery blood flow in patients undergoing coronary revascularization

Background:

Left stellate ganglion blockade (LSGB) may have additive effect to topical administration of papaverine on prevention of vasospasm of left internal thoracic artery (LITA).

Aims:

This study aims to compare LITA blood flow with topical application of papaverine alone or in combination with LSGB.

Setting:

Tertiary care hospital.

Design:

Prospective randomized controlled study.

Materials and Methods:

A total of 100 patients operated for coronary revascularization were randomly and equally allocated into two groups. In control Group-C, papaverine was applied topically during the dissection of LITA. In Group-S, the additional LSGB was performed. Blood flow was measured from cut end of the LITA for 15 s. Primary objectives of the evaluation were to observe differences in the LITA blood flow. Observing incidence of radial-femoral arterial pressure difference after cardiopulmonary bypass (CPB) was secondary objective.

Statistical Analysis:

Student's unpaired t-test and Fisher's exact test to find out a significant difference between the groups.

Results:

LITA flow in Group-S was insignificantly more (49.28 ± 7.88 ml/min) than Group-C (47.12 ± 7.24 ml/min), (P = 0.15). Radio-femoral arterial pressure difference remained low for 40 min after termination of CPB in the Group-S compared to the Group-C (−0.99 ± 1.85 vs. −1.92 ± 2.26).

Conclusion:

Combining LSGB with papaverine does not increase the LITA blood flow compared to when the papaverine is used alone. However, ganglion blockade reduces radial-femoral arterial pressure difference after CPB. Blockade can be achieved successfully under the ultrasound guidance without any complications.

Tam D, Hare DL, Girardi LN, Biondi‐Zoccai G, E. Fremes S. Angiographic Patency of Coronary Artery Bypass Conduits: A Network Meta-Analysis of Randomized Trials

Background Several randomized trials have compared the patency of coronary artery bypass conduits. All of the published studies, however, have performed pairwise comparisons and a comprehensive evaluation of the patency rates of all conduits has yet to be published. We set out to investigate the angiographic patency rates of all conduits used in coronary bypass surgery by performing a network meta-analysis of the current available randomized evidence. Methods and Results A systematic literature search was conducted for randomized controlled trials comparing the angiographic patency rate of the conventionally harvested saphenous vein, the no-touch saphenous vein, the radial artery (RA), the right internal thoracic artery, or the gastroepiploic artery. The primary outcome was graft occlusion. A total of 4160 studies were retrieved of which 14 were included with 3651 grafts analyzed. The weighted mean angiographic follow-up was 5.1 years. Compared with the conventionally harvested saphenous vein, both the RA (incidence rate ratio [IRR] 0.54; 95% CI, 0.35-0.82) and the no-touch saphenous vein (IRR 0.55; 95% CI, 0.39-0.78) were associated with lower graft occlusion. The RA ranked as the best conduit (rank score for RA 0.87 versus 0.85 for no-touch saphenous vein, 0.23 for right internal thoracic artery, 0.29 for gastroepiploic artery, and 0.25 for the conventionally harvested saphenous vein). Conclusions Compared with the conventionally harvested saphenous vein, only the RA and no-touch saphenous vein grafts are associated with significantly lower graft occlusion rates. The RA ranks as the best conduit. Registration URL: https://www.crd.york.ac.uk/prospero; Unique identifier: CRD42020164492.

Long-term Outcome 10 Years After Free Gastroepiploic Artery Graft for Coronary Artery Bypass Surgery

BACKGROUND

The long-term benefits of "free" gastroepiploic artery (GEA) grafts remain unclear. The aim of this study is to investigate the long-term patency and clinical results of en bloc free GEA grafts.

METHODS

Of the 1478 patients undergoing coronary artery bypass graft surgery at our institution between January 1997 and December 2009, 137 patients underwent en bloc free GEA grafting. Graft patency, late survival, and freedom from major adverse cardiovascular events were examined. Propensity score matching was used to compare the patency of free GEA grafts with the saphenous vein grafts, and 134 matched pairs were generated.

RESULTS

The early patency rate of free GEA grafts was 98.6%. The long-term patency rates of the free GEA grafts was 96.5% at 5 years, 95% at 10 years, and 86.6% at 15 years. In the 134 matched pairs, the long-term patency rates of free GEA grafts anastomosed to the right coronary artery were significantly higher than those of saphenous vein grafts to the right coronary artery (97% vs 91.8% at 5 years; 95.3% vs 79.6% at 10 years; 85.9% vs 61.7% at 15 years; P < .001). Survival was 94% at 5 years, 86.6% at 10 years, and 66.8% at 15 years; and freedom from major adverse cardiovascular events was 93.2% at 5 years, 91.3% at 10 years, and 73.1% at 15 years.

CONCLUSIONS

En bloc free GEA grafts had favorable long-term performance and can be considered as an effective option for patients who need to receive as many arterial grafts as possible.

Quantitative estimation of LIMA blood flow between extraluminal papavarine vs extraluminal papavarine plus intraluminal vasodilator cocktail in CABG patients

Objective:

In this study, we aimed at a comparative quantitative estimation of the difference in LIMA blood flow between LIMAs treated with topical papaverine alone and LIMAs treated with a combination of topical papaverine plus an intraluminal cocktail of papaverine, nitroglycerine, and milrinone.

Methods:

Nearly 50 consecutive patients with similar demographics undergoing elective on-pump CABG were recruited for the study. After pedicled LIMA harvest, topical papaverine was sprayed on the pedicle and kept enveloped in papaverine soaked gauze. LIMA flow was then estimated. Later, intraluminal vasodilator solution of papaverine, NTG, milrinone, and heparinized blood were instilled in LIMA, and LIMA flows were estimated.

Results:

The mean LIMA flows with topical papaverine alone was 47.19 mL/min whereas the mean LIMA flows with topical papaverine plus intraluminal cocktail was 104 mL/min. There was a significant difference between the two flows as their mean was 56.815 mL/min and the paired t-test for significance had a P value of 0.0001.

Conclusion:

There was a significant difference in the LIMA flow when the LIMA had been treated with the intraluminal instillation of the vasodilator cocktail in addition to the topical application of papaverine solution. Therefore, intraluminal vasodilator cocktail of milrinone, NTG, and papaverine mixed with heparinized blood in addition to topical papaverine is a simple and effective method for LIMA preparation in CABG.

Visualization of Spatially-Controlled Vasospasm by Sympathetic Nerve-Mediated ROCK Activation

Contraction of vascular smooth muscle is regulated primarily by calcium concentration and secondarily by ROCK activity within the cells. In contrast to the wealth of information regarding regulation of calcium concentration, little is known about the spatiotemporal regulation of ROCK activity in live blood vessels. Here, we report ROCK activation in subcutaneous arterioles in a transgenic mouse line that expresses a genetically encoded ROCK biosensor based on the principle of Fӧrster resonance energy transfer by two-photon excitation in vivo imaging. Rapid vasospasm was induced upon laser ablation of arterioles, concomitant with a transient increase in calcium concentration in arteriolar smooth muscles. Unlike the increase in calcium concentration, vasoconstriction and ROCK activation continued for several minutes after irradiation. Both the ROCK inhibitor, fasudil, and the ganglionic nicotinic acetylcholine receptor blocker, hexamethonium, inhibited laser-induced ROCK activation and reduced the duration of vasospasm at the segments distant from the irradiated point. These observations suggest that vasoconstriction is initially triggered by a rapid surge of cytoplasmic calcium and then maintained by sympathetic nerve-mediated ROCK activation.

Different vasoreactivity of arterial bypass grafts versus native coronary arteries in response to acetylcholine

BACKGROUND

Coronary angiography is often performed in patients with recurrent angina after successful coronary artery bypass grafting (CABG) in search of the progression of atherosclerosis. However, in many of these patients, no relevant stenosis can be detected. We speculate that coronary spasm may be associated with angina in these patients.

METHODS

From 2307 patients with unobstructed coronaries who underwent intracoronary acetylcholine spasm provocation testing (ACh-test) between 2012 and 2016, 54 consecutive patients who fulfilled the following inclusion criteria were included in this cohort study: previous left internal thoracic artery (LITA) bypass on the left anterior descending (LAD) coronary artery, ongoing/recurrent angina pectoris, no significant (< 50%) coronary artery or bypass stenosis. In all participants, the ACh-test was performed via the LITA bypass.

RESULTS

In 14 patients (26%) the ACh-test elicited epicardial spasm of the LAD distal to the anastomosis (≥ 90% diameter reduction with reproduction of the patient's symptoms and ischemic ECG shifts). Microvascular spasm (reproduction of symptoms and ischemic ECG-changes but no epicardial spasm) was seen in 30 patients (55%). The ACh-test was normal in the remaining 10 patients (19%). ACh-testing did not elicit any relevant vasoconstriction in the LITA bypasses in contrast to the LAD on quantitative coronary analyses (4.89 ± 7.36% vs. 52.43 ± 36.07%, p < 0.01).

CONCLUSION

Epicardial and microvascular coronary artery spasm are frequent findings in patients with ongoing or recurrent angina after CABG but no relevant stenosis. Vasoreactivity to acetylcholine is markedly different between LITA bypasses and native LAD arteries with vasoconstriction almost exclusively occurring in the LAD.

Differential myocardial strain in the early postoperative period in patients receiving arterial vs venous bypass grafts: A hypothesis-generating study

OBJECTIVE

Revascularization via coronary artery bypass grafting (CABG) remains a common therapy for coronary artery disease. CABG-based revascularization is most commonly performed via either single arterial graft (SAG) or multiple arterial grafting (MAG) strategies. Echo-derived global and regional longitudinal strain was used to test where SAG or MAG results in immediate differences in left ventricular (LV) function after CABG.

MATERIALS AND METHODS

Pre- and postprocedural intraoperative transesophageal echos were prospectively collected. Two-dimensional LV images were analyzed for global and regional longitudinal strain (GLS), LV ejection fraction, end-diastolic volume, end-systolic volume, and stroke volume (SV).

RESULTS

Twenty patients underwent open, on-pump CABG (63.9 ± 10 years old, 85% male; 10 with SAG and 10 with MAG. Preprocedural GLS significantly differed between patients with SAG and MAG, with patients with MAG having greater GLS (mean [standard deviation, SD], 20.41 [5.54]) than patients with SAG (16.28 [3.48]). After CABG, in patients with MAG, LV strain decreased both globally (-1.13 [3.15]) and regionally in the anterior-lateral (-1.22 [3.84]) and inferior-lateral regions (-1.32 [5.69]), along with LVEF. In patients with SAG, LV strain increased after CABG globally (1.34 [2.73]) and regionally in the anterior-lateral (1.20 [6.49]) and inferior-lateral regions (0.39 [7.26]), as did LVEF and SV. Postprocedure, more patients with MAG were given vasopressor (100% vs 60%) and inotrope infusions (70% vs 40%) than patients with SAG.

CONCLUSIONS

After CABG, LV function quantified through GLS changes both globally and regionally increased after SAG and decreased after MAG. This finding may have important clinical implications in terms of optimizing intraoperative management for patients with CABG and have the potential to guide the improvement of clinical outcomes.

Reasons for Conversion and Adverse Intraoperative Events in Robotically Enhanced Minimally Invasive Coronary Artery Revascularization

OBJECTIVE

The transition from sternotomy access to minimally invasive coronary artery bypass grafting is associated with steep learning curves. This study reports the reasons for sternotomy conversions from robotically enhanced minimally invasive direct coronary artery bypass grafting (RE-MIDCAB) and describes potential risk reduction strategies.

METHODS

The perioperative data of 759 RE-MIDCAB patients (mean age 65.9 ± 10 years, 25.5% female, 30.2% multivessel disease) operated between July 1, 2002 and November 30, 2018 were reviewed for the reasons of conversion and adverse intraoperative events. Hybrid revascularization was planned in 204 (26.9%) patients.

RESULTS

Sternotomy conversion occurred in 30 (4.0%) patients. Lung adhesions and unsuccessful single-lung ventilation prohibited safe RE-MIDCAB internal thoracic artery (ITA) harvesting in 11 (36.7%) and 1 (3.3%) patients, respectively. ITA dysfunction (n = 11, 36.7%) and inadequate target vessel visualization (n = 3, 10.0%) were among the anatomical reasons for conversions. Adverse intraoperative events included ventricle perforation (n = 1, 3.3%) and sustained ventricular arrhythmia (n = 1, 3.3%). The in-hospital mortality and mean length of hospitalization for sternotomy conversion were 3.3% (n = 1 of 30) and 13.4 ± 14.5 days, respectively. Perioperative morbidities included pneumonia (n = 4, 13.3%). Premorbid renal dysfunction predicted sternotomy conversion at the 5% level of significance.

CONCLUSIONS

RE-MIDCAB provides an attractive surgical platform for primary- or hybrid coronary artery procedures. The progressive increase in patient risk profiles, strict quality control, and focus on clinical governance require awareness of reasons that potentially contribute RE-MIDCAB to sternotomy conversion to ensure safe and sustainable programs.

Is the result of modified Allen’s test still accurate after endoscopic thoracic sympathectomy?

Background

The radial artery (RA) is increasingly being used for coronary artery bypass grafting (CABG). Endoscopic thoracic sympathectomy (ETS) has been shown to block innervation of sympathetic nerves of upper limbs, which reduces sweating of hands and dilates blood vessels. The modified Allen’s test (MAT) is one of the commonest methods of assessing collateral arm flow prior to RA harvest, though it has limitations. However, the reliability of MAT after ETS remains unclear. We therefore investigated the effects of ETS on the results of MAT.

Methods

A retrospective cohort study was conducted on 164 consecutive Chinese patients with palmar hyperhidrosis who underwent ETS between January 2016 and January 2019. The medical records were reviewed concerning the ultrasound examination and MAT results of their RAs and ulnar arteries (UAs) in both forearms before and after ETS.

Results

The performance of ETS significantly increased the diameter of the right RA from 2.731±0.122 to 3.102±0.114 mm in men and from 2.347±0.074 to 2.915±0.162 mm in women. Similar effects of ETS were observed in expanding the diameters of the left RA and the UA. Meanwhile, there was no significant effect of ETS on systolic blood pressure (BP) and heart rate (HR). Overall, retesting of patients following ETS with a preoperative positive MAT result revealed a transition to a negative result.

Conclusions

ETS was effective in dilating RA in both men and women, which could lead to a false negative preoperative MAT result. Patients should be questioned about their history of ETS if their RAs are to be harvested for CABG. More studies are warranted to evaluate the safety of RA as a coronary artery graft after ETS.

Preventing spasm of the radial artery conduit during coronary artery bypass grafting: Nicardipine versus verapamil

BACKGROUND AND AIM OF THE STUDY

In vitro studies have shown a reduction in radial artery spasm with the use of calcium antagonists. The purpose of this study was to evaluate the efficacy of topical treatment of the radial artery conduit using either verapamil or nicardipine before the anastomoses.

METHODS

This prospective randomized study included 131 patients, who underwent coronary artery bypass grafting surgery with the use of the radial artery as a conduit. In 65 patients, the harvested radial artery was topically treated with verapamil and in 66 patients with nicardipine. After harvesting the radial artery, the direct flow through the conduit was measured in vitro before 5-minute incubation in nicardipine or verapamil and measured again after incubation. The flow before and after incubation was compared. Postincubation flow was also compared in the two groups. After performing the anastomosis, the flow through the radial artery was measured in vivo.

RESULTS

The mean flow after NaCl incubation was 19.93 ± 12.66 mL/min and after incubation in the Ca+ channel blocker 47.16 ± 14.58 mL/min (P < .001). No significant difference in postincubation free flow was found between verapamil (46.29 ± 15.43 mL/min) and nicardipine (48.01 ± 13.77 mL/min; P = .503).

CONCLUSION

Topical treatment with Ca+ channel blockers reduces radial artery spasm and significantly increases the free flow through the radial artery conduit. Nicardipine is a safe and effective alternative of verapamil in preventing spasm of radial artery conduit.

How do surgeons decide? Conduit choice in coronary artery bypass graft surgery in the UK†

OBJECTIVES

Conduits used in coronary artery bypass grafting may have significant impact on outcomes, but evidence is mixed and there is large variation in practice. This study provides insights into the opinions of the UK surgeons on conduit use and their decision-making processes.

METHODS

A questionnaire was created using the Ottawa Decision Support Framework to elicit the importance that surgeons placed on bilateral internal mammary artery grafting, skeletonization, total arterial revascularization and sequential anastomoses on a scale of 1-10. Scores ≥8 were deemed 'important' and ≤3 'not important'. Surgeons were asked to specify changes to practice in frail patients or emergencies. Additional questions included conduit type used, factors affecting decision-making and vein harvesting methods. Questionnaires were administered in person with data analysed centrally.

RESULTS

Ninety-seven consultant cardiac surgeons from 25 centres responded. Thirty-two percent surgeons routinely used radial arteries and 36% used right internal mammary artery. High-quality evidence contributed most to decision-making receiving a total of 328/960 points, with consultant experience being the second (255/960 points). There was a bimodal distribution of perceived importance of bilateral internal mammary artery use, with 29 (30%) 'important' and 'not important' scores each. 23% of surgeons found total arterial revascularization important. Most surgeons (64%) preferred pedicled mammary arteries. Twenty-six percent of surgeons considered sequential grafting to be important.

CONCLUSIONS

Low uptake of total arterial revascularization and bilateral internal mammary artery among the UK consultants may be due to the lack of high-quality evidence demonstrating a significant benefit. It is also possible that reluctance to use certain conduits may stem from low levels of exposure to conduits or inadequate training, particularly given the importance of consultant experience on decision-making.

Right internal thoracic or radial artery as the second arterial conduit for coronary artery bypass surgery

PURPOSE OF REVIEW

To summarize the available evidence on the use of the right internal thoracic artery (RITA) and the radial artery as the second arterial graft in coronary artery bypass surgery.

RECENT FINDINGS

The current data support the equipoise of the two conduits in terms of clinical and angiographic outcomes. Both RITA and radial artery have better patency than saphenous vein grafts. The use of the RITA carries an increased risk of deep sternal wound infection (DSWI) if the artery is harvested as pedicle. Bilateral internal thoracic artery grafting is more technically demanding than radial artery use and there is a volume-outcome relationship in terms of mortality and incidence of DSWI. The radial artery is preferable over RITA in right-sided or distal circumflex artery targets with high-degree stenosis and in patients at higher risk for DSWI, whereas it is not recommended to graft vessels with moderate stenosis and in cases of insufficient collateralization from the ulnar artery or previous transradial procedures.

SUMMARY

The patency rate and clinical outcomes of radial artery and RITA are similar. The use of one or the other should be based on a careful evaluation of the patient's coronary anatomy and comorbidities, the conduit availability and the surgeon's and center's experience.

Role of botulinum neurotoxin-A in cerebral revascularization graft vasospasm prevention: current state of knowledge

Graft stenosis and occlusion remain formidable complications in cerebral revascularization procedures, which can lead to significant morbidity and mortality. Graft vasospasm can result in early postoperative graft stenosis and occlusion and is believed to be at least partially mediated through adrenergic pathways. Despite various published treatment protocols, there is no single effective spasmolytic agent. Multiple factors, including anatomical and physiological variability in revascularization conduits, patient age, and comorbidities, have been associated with graft vasospasm pathogenesis and response to spasmolytics. The ideal spasmolytic agent thus likely needs to target multiple pathways to exert a generalizable therapeutic effect. Botulinum toxin (BTX)-A is a powerful neurotoxin widely used in clinical practice for the treatment of a variety of spastic conditions. Although its commonly described paradigm of cholinergic neural transmission blockade has been widely accepted, evidence for other mechanisms of action including inhibition of adrenergic transmission have been described in animal studies. Recently, the first pilot study demonstrating clinical use of BTX-A for cerebral revascularization graft spasm prevention has been reported. In this review, the mechanistic basis and potential future clinical role of BTX-A in graft vasospasm prevention is discussed.

Botulinum toxin to improve vessel graft patency in cerebral revascularization surgery: report of 3 cases

Surgical revascularization continues to play an important role in the management of complex intracranial aneurysms and ischemic cerebrovascular disease. Graft spasm is a common complication of bypass procedures and can result in ischemia or graft thrombosis. The authors here report on the first clinical use of botulinum toxin to prevent graft spasm following extracranial-intracranial (EC-IC) bypass. This technique was used in 3 EC-IC bypass surgeries, 2 for symptomatic carotid artery occlusions and 1 for a ruptured basilar tip aneurysm. In all 3 cases, the harvested graft was treated ex vivo with botulinum toxin before the anastomosis was performed. Post-bypass vascular imaging demonstrated patency and the absence of spasm in all grafts. Histopathological analyses of treated vessels did not show any immediate endothelial or vessel wall damage. Postoperative angiograms were without graft spasm in all cases. Botulinum toxin may be a reasonable option for preventing graft spasm and maintaining patency in cerebral revascularization procedures.

RhoA/rho-kinase, nitric oxide and inflammatory response in LIMA during OPCABG with isoflurane preconditioning

Background

Grafting vessel with LIMA to the left anterior descending coronary artery plays a most important role in the long-term prognosis of OPCABG surgery. The aim of this study was to compare the effects of isoflurane preconditioning on miRs and mRNAs levels in the left internal mammary arterie (LIMA) graft with propofol in patients undergoing off-pump coronary artery bypass surgery (OPCABG).

Methods

Patients were randomly assigned to receive either propofol (n = 15), or interrupted isoflurane (n = 15). In group P, propofol administration was continued at 3–5 mg/kg/h intravenous injection for the duration of surgery. Five minutes prior to incision, patients of the isoflurane group (group Iso) received 2 cycles of 1 MAC isoflurane.

Results

miR-221 were significantly lower in group Iso (P < 0 .05). E-selectin mRNA, RhoA mRNA and ROK mRNA were significantly lower at specimens of LIMA in group Iso compared with those in group P patients (P < 0 .05). The expression of NOS3 mRNA was significantly higher in group Iso patients (P < 0 .05).

Conclusion

Our findings provide some insight that prior interrupted isoflurane administration could regulate miR-221, and downstream effectors (mRNAs) and resulted in actual attenuation of inflammation and spasm of LIMA in patients undergoing OPCABG surgery.

Trial registration

NCT No. (ClinicalTrials.gov): NCT02678650; Registration date: January 23, 2016.

Fatal Vasospasm of the Coronary Arteries in a Patient Undergoing Distal Bypass Surgery and Endovascular Therapy for Threatened Lower Limbs Due to Acute Exacerbation of Peripheral Arterial Disease

A 79-year-old man with a heavy smoking history presented with threatened lower limbs due to acute exacerbation of peripheral artery disease (PAD). He underwent emergent distal bypass surgery for the right leg and external iliac stenting for the left leg. Fatal coronary artery spasm (CAS) with ST segment changes on electrocardiography was observed 28 h after the procedures, resulting in cardiac arrest. Coronary angiography showed widespread CAS with improvement after intra-arterial nitroglycerin infusion. We should keep in mind that CAS may occur more frequently than expected in PAD patients, especially those who have not stopped smoking prior to revascularization.

How I deploy arterial grafts

There are currently around one million coronary artery bypass graft (CABG) procedures performed worldwide annually and despite two decades of evidence to support the use of a second arterial graft, if not total arterial grafting, the stark reality is that in contemporary practice 80% of all grafts used for CABG are saphenous vein grafts (SVG). The following description of how I deploy arterial grafts has been developed over more than two decades of clinical practice and largely self-taught by a process of "trial and error" and most importantly dictated by "ease of use" rather than personal robust angiographic data of long-term patency (although there is other such existing data in the literature for some of these techniques). The fact that there are numerous potential variants of deploying multiple arterial grafts underpins the fact that there is no single operation that is ideal in every patient-it is not a case of "one size fits all" as would be the situation for the use of a single internal thoracic artery (ITA) and supplemental vein grafts.