The internal mammary artery perforator flap in pharyngoesophageal, cervical tracheal, and cutaneous neck reconstruction

The internal mammary artery perforator (IMAP) flap is an evolution of the deltopectoral flap that is harvested based upon a single perforator from the internal mammary artery. Its favorable characteristics include pliability as a fasciocutaneous flap, ease of harvest, and minimal donor site morbidity. In this paper, we report our harvest technique and the versatility of the IMAP flap for pharyngoesophageal, cervical tracheal, and cutaneous neck defects. We seek to highlight the IMAP as a useful regional reconstructive option in both the primary and salvage reconstructive setting. As such, this flap is an important option in the head and neck reconstructive surgeon's armamentarium.

Long-term observational angiographic patency and perfect patency of radial artery compared with saphenous vein or internal mammary artery in coronary bypass surgery

OBJECTIVES

It is uncertain if the long-term biological behavior of the radial artery as a conduit for coronary bypass surgery has a similar resistance to the development of atherosclerosis as for the internal mammary artery. We aimed to examine long-term angiographic patency and disease-free patency (perfect patency) for internal mammary artery, radial artery, and saphenous vein grafts.

METHODS

A retrospective, single-center, individual patient cohort study of angiographic observations from patients' latest postoperative angiogram from 1997 to 2020 was performed. Analysis was per anastomosis and assessed for patency and perfect patency. A generalized linear mixed model premised upon logistic regression was used to minimize confounding bias.

RESULTS

A total of 983 patients with 3064 grafts were included, with a median follow-up of 8.6 (interquartile range, 4.4-12.6) years after the operation. Multivariable analysis revealed differences for radial (patency, 86.9%; perfect patency, 86.4%) and internal mammary artery (patency, 93.9%; perfect patency, 93.5%) versus saphenous vein graft (patency, 72.8%; perfect patency, 46.2%). There were no differences between the 2 arterial conduits for patency (odds ratio, 1.40; 95% CI, 0.85-2.33; P = .189) and perfect patency (odds ratio, 1.14; 95% CI, 0.71-1.84; P = .578). If a conduit was patent, then 99.4% of radial artery, 99.6% of internal mammary artery, and 63.5% of saphenous vein graft were reported as perfectly patent.

CONCLUSIONS

Radial artery and internal mammary artery had similar patency and perfect patency while both were superior to saphenous vein graft.

Outcomes of Radial Artery Versus Saphenous Vein as A Second Conduit After Coronary Artery Bypass Grafting

Despite the advantages of multiarterial grafting, saphenous vein (SV) configurations predominate in coronary artery bypass grafting (CABG). In addition, the benefits of radial artery (RA) utilization in multivessel CABG remain unclear. This study aims to compare the clinical outcomes of patients who received RA grafts during CABG with those of patients who received SV grafts. A retrospective, single-institution cohort study was performed in 8,774 adults who underwent isolated CABG surgery with multiple grafts between 2010 and 2022. To balance graft cohorts, propensity score matching (PSM) was performed using a 1:2 (RA/SV) match ratio. Long-term postoperative survival was compared in RA and SV graft groups. Similarly, major adverse cardiac and cerebrovascular event (MACCE) rates were compared in the cohorts, with MACCE comprising death, myocardial infarction (MI), coronary revascularization, and stroke. Kaplan-Meier estimation was performed for both mortality and MACCE. A total of 7,218 patients (82.3%) who underwent multivessel CABG were included in this analysis. Of these patients, 341 (4.7%) received RA grafts, and 6,877 (95.3%) received SV grafts secondary to left internal mammary artery use. PSM yielded a cohort of 335 patients with RA and 670 patients with SV. After matching, groups were well balanced across all baseline variables. No significant differences were observed in either immediate postoperative morbidities or long-term survival. However, Kaplan-Meier estimates of long-term postoperative freedom from MACCE were significantly greater in matched patients with SV (73.3%) than in those with RA (67.4%) (p = 0.044, cluster log-rank), with patients with SV also possessing significantly greater freedom from coronary revascularization and MI. In conclusion, RA and SV secondary conduits for CABG were associated with comparable immediate postoperative complications and long-term survival after PSM. SV grafting was associated with significantly decreased rates of postoperative MACCE, likely owing to lower rates of coronary revascularization and MI than in RA grafting.

Traumatic Pseudoaneurysms of the Internal Mammary Artery: Two Cases and Percutaneous Intervention

Pseudoaneurysms involving the internal mammary artery/internal thoracic artery (IMA/ITA) are rare occurrences, and the presentation and treatment approaches for such cases can be variable. Due to the potentially life-threatening risk of rupture, leading to conditions like hemothorax, it is important to have a comprehensive understanding of safe and effective diagnostic and therapeutic techniques. We present two cases of IMA/ITA artery pseudoaneurysms. A 91-year-old male presented to the emergency department following a motor vehicle accident. A CT scan of the chest revealed an anterior mediastinal hemorrhage with active extravasation. Percutaneous intervention revealed a pseudoaneurysm arising from a left IMA/ITA side branch. Coil embolization effectively treated the pseudoaneurysm. In the second case, a 79-year-old male presented with a sternal fracture after a ground-level fall, with parasternal hematoma and active bleeding (pseudoaneurysm) on Trauma Computerized Tomography of the chest with contrast. He underwent coil embolization, and subsequent post-procedure angiograms confirmed the effective occlusion of the left IMA/ITA, with no further visualization of the pseudoaneurysm. These two cases underscore the importance of tailored approaches in treating internal mammary artery pseudoaneurysms.

Impact of Preoperative Quantitative Flow Ratio of the Left Anterior Descending Artery on Internal Mammary Artery Graft Patency and Midterm Patient Outcomes After Coronary Artery Bypass Grafting

Background In coronary artery bypass grafting, grafting a target vessel with nonsignificant stenosis increases the risk of graft failure. The present study aims to investigate the impact of preoperative quantitative flow ratio (QFR), a novel functional assessment of the coronary artery, on internal mammary artery graft failure rate and midterm patient outcomes. Methods and Results Between January 2016 and January 2020, we retrospectively included 419 patients who underwent coronary artery bypass grafting who had received preoperative angiography and postoperative coronary computed tomographic angiography in our center. QFR of the left anterior descending (LAD) artery was computed based on preoperative angiograms. The primary end point was the failure of the graft on the LAD artery assessed by coronary computed tomographic angiography at 1 year, and the secondary end point was major adverse cardiac and cerebrovascular events including death from any cause, myocardial infarction, stroke, or repeat revascularization. Grafts on functionally nonsignificant LAD arteries (QFR >0.80) had a significantly higher failure rate than those on functionally significant LAD arteries (31.4% versus 7.2%, P<0.001). QFR outperforms degree of stenosis in discriminating graft failure (C statistic, 0.76 versus 0.58). Clinical follow-up (3.6 years, interquartile range [3.3-4.1]) was accomplished in 405 patients, and the rate of major adverse cardiac and cerebrovascular events was significantly higher among patients with functionally nonsignificant LAD arteries (10.1% versus 4.2%; adjusted hazard ratio, 3.08 [95% CI, 1.18-8.06]; P=0.022). Conclusions In patients receiving internal mammary artery to LAD artery coronary artery bypass grafting, preoperative QFR of the LAD artery of >0.80 was associated with a higher graft failure rate at 1 year and worse patient outcomes at the 3.6-year follow-up.

Late Clinical Outcomes of Total Arterial Revascularization or Multiple Arterial Grafting Compared to Conventional Single Arterial with Saphenous Vein Grafting for Coronary Surgery

Coronary surgery provides better long-term outcomes than percutaneous coronary intervention. Conventional practice is to use a single arterial conduit supplemented by saphenous vein grafts. The use of multiple arterial revascularization (MAG), or exclusive arterial revascularization (TAR), however, is reported as having improved late survival. Survival is a surrogate for graft failure that may lead to premature death, and improved survival reflects fewer graft failures in the non-conventional strategy groups. The reasons for not using MAG or TAR may be due to perceived technical difficulties, a lack of definitive large-scale randomized evidence, a lack of confidence in arterial conduits, or resources or time constraints. Most people consider radial artery (RA) grafting to be new, with use representing approximately 2-5% worldwide, despite select centers reporting routine use in most patients for decades with improved results. In conclusion, the current body of evidence supports more extensive use of total and multiple arterial revascularization procedures in the absence of contraindications.

Quantification of the internal mammary artery size in Aboriginal and Torres Strait islanders

BACKGROUND

Variation in size of the internal mammary artery has been demonstrated in ethnic groups, but not reported in Aboriginal patients. We hypothesised that the left internal mammary artery is smaller in Aboriginal patients compared to non-Aboriginal patients and aimed to determine the impact on survival following coronary artery bypass graft (CABG) surgery.

METHODS

Left internal mammary artery size was compared between Aboriginal (n = 345) and non-Aboriginal (n = 1819) in 2343 patients undergoing CABG at Flinders Medical Centre from January 2010 to June 2021. To determine the association with-survival we used Kaplan-Meier survival analysis and Cox proportional hazard models adjusted for preoperative variables.

RESULTS

There was a significant difference in left internal mammary artery (LIMA) size-Aboriginal 1.8 ± 0.4 mm; non-Aboriginal 2.1 ± 0.4 mm (P < 0.001)-and left anterior descending (LAD) artery size-Aboriginal 1.7 ± 0.3 mm; non-Aboriginal 1.9 ± 0.3 mm (P < 0.001). Aboriginal patients were more likely to have the LIMA discarded (9.3% vs. 0.4%) and to receive a LAD vein graft (17% versus 3%) (P < 0.001). There was no difference in 30-day mortality or survival <5 years.

CONCLUSION

This study supports the hypothesis that the left internal mammary artery is smaller in Aboriginal patients compared to non-Aboriginal patients. Although Aboriginal patients were more likely to receive a venous conduit to the LAD, we observed no difference in survival up to 5 years. This data contrasts with reported outcomes of other ethnic groups.

Right Internal Mammary Artery Occlusion in a Patient With Failed Left Internal Mammary Artery Coronary Artery Bypass Graft Surgery Post a Laparoscopic Appendectomy for Acute Appendicitis

Patients who present with acute myocardial infarction are often urgently evaluated for possible revascularization via coronary artery bypass graft surgery (CABG), percutaneous coronary intervention (PCI), or medical therapy alone. CABG has been shown to provide symptomatic relief as well as increased long-term survival for patients with multivessel coronary artery disease (CAD). Though venous grafts can be used to revascularize the ischemic territory, long-term patency is most successful when using pedicled coronary grafts such as the left internal mammary artery (LIMA) or right internal mammary artery (RIMA) graft. Only a fraction of patients who undergo a RIMA or LIMA will occlude their graft, and mid-graft lesions presumed secondary to atherosclerosis are even rare. For our case report, we evaluate a 72-year-old female who has had a very rare acute coronary occlusion of her mid-RIMA graft resulting in an acute apical left ventricular infarct. A heart catheterization confirmed a 100% thrombotic occlusion of the mid-RIMA-LAD, which was stented with a 2.5 x 20 mm drug-eluting stent.

Internal Mammary Arteries as a Model to Demonstrate Restoration of the Impaired Vasodilation in Hypertension, Using Liposomal Delivery of the CYP1B1 Inhibitor, 2,3',4,5'-Tetramethoxystilbene

A significant number of patients with severe cardiovascular disease, undergoing coronary artery bypass grafting (CABG), present with hypertension. While internal mammary arteries (IMAs) may be a better alternative to vein grafts, their impaired vasodilator function affects their patency. Our objectives were to (1) determine if inhibition of the cytochrome P450 enzyme CYP1B1, using liposome-encapsulated 2,3′,4,5′-tetramethoxystilbene (TMS), can potentiate vasodilation of IMAs from CABG patients, and (2) assess mechanisms involved using coronary arteries from normal rats, in an ex vivo model of hypertension. PEGylated liposomes were synthesized and loaded with TMS (mean diameter 141 ± 0.9 nm). Liposomal delivery of TMS improved its bioavailability Compared to TMS solution (0.129 ± 0.02 ng/mL vs. 0.086 ± 0.01 ng/mL at 4 h; p < 0.05). TMS-loaded liposomes alleviated attenuated endothelial-dependent acetylcholine (ACh)-induced dilation in diseased IMAs (@ACh 10−4 M: 56.9 ± 5.1%; n = 8 vs. 12.7 ± 7.8%; n = 6; p < 0.01) for TMS-loaded liposomes vs. blank liposomes, respectively. The alleviation in dilation may be due to the potent inhibition of CYP1B1 by TMS, and subsequent reduction in reactive oxygen species (ROS) moieties and stimulation of nitric oxide synthesis. In isolated rat coronary arteries exposed to a hypertensive environment, TMS-loaded liposomes potentiated nitric oxide and endothelium-derived hyperpolarization pathways via AMPK. Our findings are promising for the future development of TMS-loaded liposomes as a promising therapeutic strategy to enhance TMS bioavailability and potentiate vasodilator function in hypertension, with relevance for early and long-term treatment of CABG patients, via the sustained and localized TMS release within IMAs.

Transient phrenic nerve palsy induced by cardiac catheterisation in an infant

We report on a 7-month-old male with transient phrenic nerve palsy induced by diagnostic cardiac catheterisation. The phrenic nerve palsy, which is a rare complication, was due to extravascular bleeding from a branch of the internal mammary artery.

Setting things "right": right internal mammary artery on anomalous right coronary artery - a case report

Anomalous aortic origin of a coronary artery (AAOCA) is a rare pathology that may cause episodic ischemia owing to possible vessel compression during systolic expansion of the aortic root. This anomaly can lead to myocardial infarction, malignant arrhythmias and sudden cardiac death (SCD). Several surgical techniques have been described; however, there are no defined guidelines regarding the treatment of AAOCA. We report the case of a 47-year-old woman with ectopic origin of the right coronary artery (RCA) from the left sinus of Valsalva, with an interarterial course of the proximal segment of the artery, running between the aorta and the pulmonary trunk. Revascularization was accomplished by harvesting the right internal mammary artery (RIMA) and anastomosing it to the anomalous RCA, given the small portion of the RCA following an intramural course and our familiarity with the procedure. The RCA was ligated proximal to the anastomosis to avoid the string sign phenomenon. This procedure is safe and fast and can be considered an alternative to coronary reconstruction.

First case report of bilateral breast necrosis following coronary artery bypass graft using left internal mammary artery

Coronary artery bypass grafting (CABG) using internal mammary artery is a frequently performed procedure for the treatment of coronary artery disease nowadays. Ipsilateral breast necrosis is a rare and seldom reported complication that may mimic breast cancer on presentation. However, contralateral breast necrosis has not been reported to date. We are reporting the first case of bilateral breast necrosis after CABG using the left internal mammary artery. We discuss the different underlying mechanisms and possible co-factors behind the development of this rare complication, and we also share a successful management approach to conserve the breast and improve the patient's outcome.

Extracardiac coronary steal induced by upper limb hyperemia: a feature of internal mammary artery arteriogenesis

Function of naturally existing internal mammary artery (IMA)-to-coronary artery anastomoses has been shown by augmented blood supply to the coronary collateral circulation in response to IMA occlusion. Theoretically, this beneficial functional connection is invertible and can be linked to coronary steal, the verification of whose hypothesis would provide alternate proof to the mentioned functional evidence. This was an observational study including 40 patients with chronic coronary syndrome, distal IMA occlusion, and upper limb hyperemia (verum group), and 40 propensity score matched controls (placebo group) without IMA occlusion or hyperemia. Primary study end point was the intergroup difference and temporal development in coronary collateral function (i.e., collateral flow index; CFI) as obtained at 30, 45, and 60 s following a proximal coronary artery balloon occlusion. CFI is the ratio between simultaneous mean coronary occlusive pressure divided by mean aortic pressure both subtracted by central venous pressure. To provoke a steal phenomenon, upper limb hyperemia was induced by upper arm blood pressure cuff deflation following a 5-min suprasystolic inflation ipsilateral to the sensor-wired coronary artery with release immediately after the first CFI measurement. Between the first and the second CFI measurement, CFI change (i.e., CFI@45s - CFI@30s) was absent in the verum group whereas there was CFI recruitment in the placebo group: 0.000 ± 0.023 and +0.009 ± 0.013, respectively; P = 0.032. Among patients with artificial distal IMA occlusion, induction of ipsilateral upper limb hyperemia provokes extracardiac coronary steal as expressed by temporarily absent collateral recruitment as it normally takes place without upper limb hyperemia.NEW & NOTEWORTHY Induction of ipsilateral upper limb hyperemia provokes extracardiac coronary steal among patients with artificial distal internal mammary artery occlusion. Coronary steal via the occluded internal mammary arteries serves as alternate proof of concept of the already existing evidence of their functional extracoronary collateral supply.

Does the Nuss procedure for treating pectus excavatum compromise the long term internal mammary artery flow? A systematic review

INTRODUCTION

The Nuss procedure is the most common procedure used to treat patients with pectus excavatum. The effect of the Nuss bars on the long-term internal mammary artery flow (IMA) is not well studied. This could have an impact on patients requiring a coronary artery bypass grafting surgery after the Nuss procedure. We performed a systematic review to study the impact of the Nuss bars on the IMA long term flow.

METHODS

A Medline search from January 1990 to August 2020 was performed using [Nuss OR thoracoscopic pectus OR minimally invasive pectus] AND [Internal mammary OR Internal thoracic OR IMA OR ITA]. English language papers only were included. This trial was registered with PROSPERO under registration number CRD42021234010.

RESULTS

A total of 48 papers were identified using the reported search, of which three represented the best evidence to answer the clinical question. One study looked at the IMA flow via computed tomography (CT)-angiography on the 10th postoperative day after the Nuss procedure and found 15 out of 34 patients (44%) to have abnormal IMA blood flow but with no clinical consequences. Two studies looked at the IMA flow after removal of the Nuss-bar. The first study utilized CT-angiography on the 5th postoperative day after Nuss-bar removal and found four out of the six patients studied (67%) to have abnormal flow. The last study was composed of 19 patients and looked at IMA flow during the presence of the Nuss-bars and after its removal utilizing Doppler-angiography. It found 11 out of 19 patients (58%) to have abnormal blood flow with the bars in place. After removal of the bars, only two patients (10%) were found to have unilateral IMA obstructed flow.

CONCLUSION

In patients undergoing the Nuss procedure for management of pectus excavatum, the internal mammary artery flow is compromised in 44%-58% of patients with the bar in situ. When these patients are assessed 10 days following removal of the bar, some reversal of compromised IMA flow is evident. However, in up to 67% of patients, abnormal IMA flow remains. Further studies are required to determine whether this abnormal flow is permanent, which will require examining patients at longer follow-up intervals. Patients undergoing coronary artery bypass grafting who have a history of a Nuss procedure should receive preoperative IMA imaging.

Technical Aspects: Coronary Artery Bypass Grafting in a Case of Dextrocardia With Situs Inversus

Dextrocardia with situs inversus is a rare congenital anomaly in which the heart and the abdominal organs orient themselves in a mirror-image reversal of the normal anatomy. Coronary artery disease incidence is similar to that of the normal population. Performing coronary artery bypass grafting in this subset of the population poses few difficulties. These limitations can be overcome by few technical adjustments by the surgeon and the team which will be discussed in our article.

Conduits' Biology Regulates the Outcomes of Coronary Artery Bypass Grafting

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Accelerated atherosclerosis is common when SVGs, but not arterial grafts, are used for myocardial revascularization during CABG.

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This review will provide an overview of the available data on the most commonly used conduits in CABG, highlighting the differences in their cellular biology, mechanical, biochemical, and vasoconstrictive properties.

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Clinical and scientific evidence support the use of arterial grafts over venous conduits at the time of CABG. These arterial conduits seem to be more protected toward the development of atherosclerosis. Exploring the molecular and cellular mechanisms, of the various cell populations within these conduits, will help unveil the pathways responsible for these protective effects.

Coronary artery bypass graft (CABG) is the gold standard for coronary surgical revascularization. Retrospective, prospective, and meta-analysis studies looking into long-term outcomes of using different conduits have pointed to the superiority of arterial grafts over veins and have placed the internal mammary artery as the standard conduit of choice for CABG. The superiority of the internal mammary artery over other conduits could be attributable to its intrinsic characteristics; however, little is known regarding the features that render some conduits atherosclerosis-prone and others atherosclerosis-resistant. Here, an overview is provided of the available data on the most commonly used conduits in CABG (internal mammary artery, saphenous vein, radial artery, gastroepiploic artery), highlighting the differences in their cellular biology, mechanical, biochemical, and vasoconstrictive properties. This information should help in furthering our understanding of the clinical outcomes observed for each of these conduits.

Unmasking the Coronary-Subclavian Steal Syndrome: The Culprit Lies in the Subclavian Artery. A Report of a Case and Review of the Literature

The coronary-subclavian steal syndrome is a hemodynamic phenomenon in which a subclavian artery stenosis or occlusion impairs blood flow at the origin of the left internal mammary artery used for coronary artery bypass grafting (CABG), causing retrograde blood flow and thus provoking symptoms of cardiac ischemia and its complications. Once considered the gold-standard operation of choice, open revascularization has now been abandoned as a first line treatment and replaced by endovascular techniques. In all cases, detailed and oriented physical examination in combination with further imaging in high clinical suspicion for coronary-subclavian steal syndrome remains the sine qua non of the preoperative examination of the patient. We report the case of a 50-year-old male patient suffering from acute onset angina post- coronary artery bypass grafting and managed by endovascular means.

Coronary artery size as a predictor of Y-graft patency following coronary artery bypass surgery

This study aims to evaluate the association between target vessel size and graft patency in the right IMA-right coronary territory anastomosis.A total of 402 patients who underwent CABG between 2005 and 2016 using the right IMA Y-graft to the posterolateral branch or posterior descending artery were enrolled. Preoperative coronary angiography was utilized to measure the size of the target coronary arteries in the right territory. Follow-up angiography and computed tomography at 6 to 12 months were used to determine graft patency.Thirty patients (7.5%) were found to have occluded graft. Larger target vessel size was associated with lower risk of graft occlusion (OR: 0.18, 95% CI:0.05-0.62, P = .007). The receiver operating characteristic (ROC) curve showed that the cutoff-value of 1.93 mm was found to have the maximum sum of sensitivity and specificity for graft patency (Area under the curve (AUC): 0.65, P = .01). Excluding patients with right coronary artery total occlusion, the discriminative performance of target vessel size became more prominent (AUC: 0.76, P < .01), with same cutoff value.In the setting of bilateral IMA composite grafting, the patency of right IMA to right coronary territory was influenced by the size of the target coronary artery. The influence of target coronary artery size was prominent in non-total occlusion patients. Careful selection of a target anastomosis site is recommended.

Avoiding the Internal Mammary Artery During Parasternal Blocks: Ultrasound Identification and Technique Considerations

Fascial plane chest wall blocks are an integral component to optimal multimodal postoperative analgesia in breast and cardiothoracic surgery, facilitating faster functional recovery and earlier discharge. Pectoral nerves block and serratus plane block have been used to treat postsurgical pain after breast and cardiothoracic surgeries; however, they cannot be used to anesthetize the anterior chest wall. Ultrasound parasternal block, or pectointercostal fascial block and transversus thoracis muscle plane block are two novel ultrasound-guided anesthetic and analgesic techniques that block the anterior cutaneous branches T2 to T6 intercostal nerves, providing anesthesia and analgesia to the anterior chest wall. Ultrasound parasternal block/pectointercostal fascial block and transversus thoracis muscle plane block are performed in the region of the internal mammary artery and could be considered to treat post-thoracotomy pain. This anatomic region is innervated by the anterior cutaneous branches T2-to-T6 intercostal nerves, which are obliterated during cardiac surgery artery harvesting. At the level of the fourth parasternal rib interspace, the internal mammary artery can be identified between the internal intercostal muscle and transversus thoracis muscle as a longitudinal pulsatile structure approximately 1.5 cm from the lateral border of the sternum. The transversus thoracis muscle is variable in many people and, thus, is an unreliable target and is difficult to visualize with ultrasound. Moreover, patients with a history of coronary artery bypass grafting could have tissue disruption in the transversus thoracis plane because of the internal mammary artery harvest, making transversus thoracis muscle identification more difficult. Despite ultrasound parasternal block and transversus thoracis muscle plane block having good safety profiles and reduced risk of complications, pneumothorax, local anesthetic systemic toxicity, and internal mammary artery injury or hematoma should be considered. If the block is performed before cardiac surgery, both the right and left internal mammary arteries could be damaged. The injury could render the internal mammary artery unusable for bypass grafting. If the block is performed after left internal mammary artery harvesting at the end of coronary artery bypass grafting, only the right internal mammary artery could be damaged. In patients in whom the internal mammary artery has been surgically used and the transversus thoracis muscle is difficult to visualize, ultrasound parasternal block should be considered. In patients in whom the internal mammary artery could be difficult to visualize or considering that it is in the vicinity of the transversus thoracis muscle plane block target and that the transversus thoracis muscle is difficult to visualize with ultrasound after internal mammary artery harvesting, then ultrasound parasternal block should be considered. The authors believe that ultrasound parasternal block is the safer regional technique for protecting the internal mammary artery and the pleura because it is more superficial. For this reason, ultrasound parasternal block also could be performed by inexperienced anesthesiologists. Although ultrasound parasternal block is more superficial, its superiority in terms of safety is yet to be proven. Additional studies are warranted to validate the authors' hypothesis.

Quality of life in patients after coronary artery bypass grafting with bilateral internal thoracic artery versus single internal thoracic artery

Introduction

The left internal thoracic artery to the left anterior descending artery graft is recognized as the gold standard for coronary revascularization. We compared quality of life (QoL) in patients who received bilateral internal thoracic arteries (BITA) and those with a single internal thoracic artery (SITA) graft.

Aim

To assess QoL during a 10-year follow-up in patients who underwent coronary artery bypass grafting (CABG) with BITA vs. SITA.

Material and methods

We recruited 300 patients with multivessel coronary artery disease who underwent CABG from January 2005 to October 2010. Mean duration (standard deviation – SD) of follow-up was 3568 ±409 days. QoL was measured subjectively using a Likert scale and objectively by the WHOQOL-BREF questionnaire. Patients were interviewed by telephone.

Results

BITA patients reported marked improvement and improvement more often than SITA patients (58% vs. 43.3%, p = 0.02). Marked deterioration was noted by 2% of BITA patients and 3.3% of SITA patients (p = 0.03). Summarized results of the WHOQOL-BREF questionnaire showed significantly better QoL in the BITA group (median: 15.0) vs. SITA group (median: 14.75) (p = 0.02). There were more angina-free patients in the BITA group (84%) compared to SITA patients (72.7%) (p = 0.006). QoL did not correlate with patients’ body mass index (p = 0.10) or residence status (p = 0.51), but there was a weak negative correlation between QoL and patients’ age (r = –0.14, p = 0.01).

Conclusions

Surgical coronary revascularization using BITA improves QoL, particularly when measured by a Likert scale.

Delayed bleeding complication due to internal mammary artery injury after ultrasound-guided percutaneous catheter drainage for liver cyst infection

Background

Ultrasound-guided percutaneous catheter drainage (PCD) is widely accepted as a primary treatment for pyogenic liver abscess. Severe PCD-related complications have been reported; however, delayed bleeding complications due to internal mammary artery injury are unknown.

Case Presentation

An 84-year-old man undergoing hemodialysis owing to chronic kidney disease due to focal segmental glomerulosclerosis was admitted to our hospital for liver cyst infection. Ultrasound-guided PCD was carried out through the normal liver at the upper abdominal midline at the level of the sixth intercostal space. Two days later, an abdominal hematoma occurred at the puncture site. Contrast-enhanced computed tomography revealed extravasation of the distal right internal mammary artery, which was successfully treated with percutaneous coil embolization.

Conclusion

Internal mammary artery injury should be considered as a differential diagnosis when a progressing hematoma develops after PCD.

A false aneurysm of internal mammary artery: A case report

A false aneurysm of the internal mammary artery is a very rare clinical entity. Early and accurate diagnosis and treatment of false aneurysms of internal mammary artery are critical, as it may result in rupture, severe bleeding, and even death. Currently, endovascular therapeutic approaches such as stenting and coil embolization have been considered the first-line treatment. Herein, we report a case of false aneurysm of the internal mammary artery in the light of literature data.

A comparison of immediate postoperative complications in using left internal mammary artery + vein versus only vein as conduit in patients undergoing off-pump coronary artery bypass grafting

Objective:

The objective of the study is to compare the immediate postoperative cardiac complications in patients undergoing off-pump coronary artery bypass grafting (OPCABG) using mixed (arterial and venous grafts) versus only venous grafts and to compare the requirement of packed red cell units and intra-aortic balloon pump (IABP) in both the groups.

Materials and Methods:

This was an observational, analytical, prospective study.

Sample Size:

Fifty new patients were included in the study.

Inclusion/Exclusion Criteria:

Patients diagnosed with triple-vessel coronary artery disease (CAD) undergoing OPCABG with an ejection fraction (EF) of more than 30%. Patients who have undergone prior CABG, EF <30%, preexisting valvular heart disease, any evidence pulmonary hypertension, preoperative IABP, any history of neurological dysfunction, left atrium size more than 5.5 cm, and history of coagulation disorder was excluded from the study.

Results:

The most common immediate postoperative cardiac complication observed was atrial fibrillation followed by ventricular arrhythmias in both the groups. There was no statistically significant difference in complication rate between the two groups. Postoperative requirement of IABP and requirements of blood products were also similar in both the groups.

Conclusion:

Patients undergoing off-pump CABG have similar immediate postoperative complications irrespective of the type of conduit used.

Internal Mammary Artery Compression After Pectus Excavatum Repair Does Not Increase Risk of Hemorrhagic Complications in Pediatric Patients

Objectives: Minimal invasive repair of pectus excavatum (MIRPE) described by Nuss is the most popular correction nowadays of this deformity. During the introduction of the bars, they can hurt or compress the internal mammary arteries (IMA). The aim of this study was to observe the prevalence of IMA compression in children after MIRPE. Also, we examined if IMA obstruction increases the risk of complications at bar removal, and if these vascular changes are reversible. Materials and Methods: All patients operated on pectus excavatum in our tertiary pediatric surgical center between 2013 and 2019 were involved in the study. Data of age, sex, number of bars and characteristics of the deformity were examined. IMA flow was checked by Doppler ultrasound (DUS) after MIRPE and after bar removal, too. Results: Among 41 patients with mean age of 15.2 years there were 18 asymmetrical deformities, 23 sternal rotations. Mean pectus index was 4.01. After the Nuss procedure 7(9%) stenoses and 10(12%) occlusions of IMA were found on DUS. After bar removal 3 of 4 stenoses have resolved, but all examined occlusions (3/3) persisted. There were no complications during bar removals. Conclusion: IMA compression after MIRPE in children is uncommon, and is not influenced by severity of deformity. Obstruction of these vessels does not increase the risk of hemorrhagic complications at bar removal. Data of larger cohort are needed to determine reversibility of these changes.

Calcium-activated potassium channel family in coronary artery bypass grafts

OBJECTIVES

We examined the expression, distribution, and contribution to vasodilatation of the calcium-activated potassium (K_Ca) channel family in the commonly used coronary artery bypass graft internal thoracic artery (ITA) and saphenous vein (SV) to understand the role of large conductance K_Ca (BK_Ca), intermediate-conductance K_Ca (IK_Ca), and small-conductance K_Ca (SK_Ca) channel subtypes in graft dilating properties determined by endothelium-smooth muscle interaction that is essential to the postoperative performance of the graft.

METHODS

Real-time polymerase chain reaction and western blot were employed to detect the messenger RNA and protein level of K_Ca channel subtypes. Distribution of K_Ca channel subtypes was examined by immunohistochemistry. K_Ca subtype-mediated vasorelaxation was studied using wire myography.

RESULTS

Both ITA and SV express all K_Ca channel subtypes with each subtype distributed in both endothelium and smooth muscle. ITA and SV do not differ in the overall expression level of each K_Ca channel subtype, corresponding to comparable relaxant responses to respective subtype activators. In ITA, BK_Ca is more abundantly expressed in smooth muscle than in endothelium, whereas SK_Ca exhibits more abundance in the endothelium. In comparison, SV shows even distribution of K_Ca channel subtypes in the 2 layers. The BK_Ca subtype in the K_Ca family plays a significant role in vasodilatation of ITA, whereas its contribution in SV is quite limited.

CONCLUSIONS

K_Ca family is abundantly expressed in ITA and SV. There are differences between these 2 grafts in the abundance of K_Ca channel subtypes in the endothelium and the smooth muscle. The significance of the BK_Ca subtype in vasodilatation of ITA may suggest the potential of development of BK_Ca modulators for the prevention and treatment of ITA spasm during/after coronary artery bypass graft surgery.

Atypical Kawasaki disease: A patient with coronary, brain, and internal mammary arteritis

Here we report a rare case of atypical Kawasaki disease (KD) in a patient presenting with systemic arteritis affecting the coronary arteries, brain, and internal mammary arteries (IMAs). A 25-year-old man was referred to our institute with angina pectoris. Coronary angiography revealed coronary artery aneurysms and triple-vessel disease. Three-dimensional brain computed tomography showed multiple small saccular aneurysms on the vertebral and posterior inferior cerebellar arteries. Off-pump coronary artery bypass (OPCAB) grafting ​​​​​​was performed; however, the bilateral IMAs were tightly adhered and not patent. OPCAB was completed using the bilateral radial and gastroepiploic arteries. This is the first report of KD involving the IMA.

Reduction of plasma angiopoietin-like 2 after cardiac surgery is related to tissue inflammation and senescence status of patients

OBJECTIVES

A strong relationship between high circulating angiopoietin-like 2 (ANGPTL2) levels, a proinflammatory adipokine, and cardiovascular diseases has been reported. Our objective was to determine whether plasma ANGPTL2 and high-sensitivity C-reactive protein (hs-CRP) levels change postoperatively in patients who underwent heart valve surgery and/or coronary artery bypass grafting. We hypothesized that a corrective cardiac surgery would decrease ANGPTL2 levels.

METHODS

In 47 prospectively recruited patients who underwent coronary artery bypass grafting (n = 16), valve replacement (n = 16), or both (n = 15), we measured plasma ANGPTL2 and hs-CRP levels preoperatively, at 24 hours, at 3 to 5 days (hospital discharge), and at 30 to 90 days (follow-up) after surgery. Mediastinal adipose tissue and distal fragments of the left internal mammary artery (IMA) were harvested during surgery and mRNA expression of inflammatory and senescence markers was assessed using real-time quantitative polymerase chain reaction.

RESULTS

ANGPTL2 and hs-CRP levels were elevated 24 hours after surgery and then returned to baseline levels. We noted, however, a dichotomy among patients: compared with baseline, plasma ANGPTL2 levels either significantly decreased (n = 21/47) or increased (n = 26/47) after surgery. In contrast, hs-CRP levels were identical between groups (P = .997). Patients in the increased group were older (P = .002) with a higher systolic blood pressure (P = .038) at baseline. Moreover, changes in ANGPTL2 levels (ΔANGPTL2 = final minus initial levels) positively correlated with mRNA expression of tumor necrosis factor α and interleukin 8 in mediastinal adipose tissue and IMA (P < .05) and with the senescence-associated marker cyclin-dependent kinase inhibitor 1 in IMA (P = .009).

CONCLUSIONS

In younger patients with lower levels of tissue inflammation and arterial senescence load, ANGPTL2, but not hs-CRP levels decreased after cardiac surgery, suggesting that circulating ANGPTL2 reflects tissue inflammation and senescence.

[Endoscopic harvesting of internal mammary artery for coronary artery bypass grafting]

Endoscopic harvesting of internal mammary artery for minimally invasive coronary artery bypass surgery seems to be highly justified and expedient. Technical features of this procedure are reviewed in the article. There are certain advantages of this method including ligation of proximal branches, reduced surgical trauma, better cosmetic results and enhanced postoperative rehabilitation.

Robotic lymphadenectomy of an internal mammary lymph node metastasis

A 58-year-old woman was diagnosed with a left-sided lone internal mammary swollen lymph node on a routine follow-up computer tomography, 42 months after a left mastectomy in the context of a ductal carcinoma grade III. The suspected metastasis was successfully removed in toto using a 3-port-da Vinci robotic procedure and the patient was discharged home without any complication on the third postoperative day. Robotically assisted oncological lymph node removal is safe, easily performed and economically affordable.

Mechanisms Responsible for Serotonin Vascular Reactivity Sex Differences in the Internal Mammary Artery

Background

The increased adverse cardiac events in women undergoing coronary artery bypass grafting are multifactorial and may include clinical, psychosocial, and biological factors. Potential contributing biological factors could include vascular hyperreactivity of the internal mammary artery (IMA) to endogenous vasoconstrictors in women, resulting in a predilection to myocardial ischemia. This study evaluated sex differences in serotonin and thromboxane A₂ dependent vasoconstriction in human isolated IMA, with the mechanistic role of (1) the endothelium, (2) nitric oxide (NO), (3) prostaglandins, and (4) receptor activity investigated for any observed sex difference.

Methods and Results

Viable isolated human IMA segments were obtained from 116 patients (44 women [mean age, 66.8±12.2 years] and 72 men [mean age, 66.6±10.4 years]) undergoing coronary artery bypass grafting. Cumulative concentration‐response curves for serotonin and thromboxane A₂ mimetic, U46619, were determined and revealed an increased sensitivity to serotonin but not U46619 in women. This sex difference to serotonin was further assessed by the following: (1) endothelial denudation, (2) endothelial NO synthase inhibition and NO quantification using electron paramagnetic resonance, (3) cyclooxygenase inhibition and prostaglandin metabolite quantification using mass spectrometry, and (4) quantification of receptor activity status. The female hyperreactivity to serotonin was (1) abolished by endothelial denudation; (2) unaffected by NO synthase inhibition, with no difference in electron paramagnetic resonance–assessed NO levels; (3) abolished by cyclooxygenase inhibition (quantification of prostaglandins in IMA revealed a trend towards reduced 6‐keto prostaglandin F1α in female IMA; P=0.08); and (4) unrelated to receptor activity.

Conclusions

These data indicate that female IMAs are hyperreactive to serotonin but not U46619, with the former attributable to an endothelium‐dependent cyclooxygenase pathway.

Effect of Permanent Right Internal Mammary Artery Closure on Coronary Collateral Function and Myocardial Ischemia

BACKGROUND

The objective of this study is to test the effect of permanent right internal mammary artery device closure on coronary collateral function and myocardial ischemia.

METHODS AND RESULTS

This was a prospective, open-label clinical trial in 50 patients with coronary artery disease. The primary study end point was coronary collateral flow index as obtained during a 1-minute proximal right coronary artery (RCA) and left coronary artery balloon occlusion at baseline before and at follow-up examination 6 weeks after distal right internal mammary artery device closure. Collateral flow index is the ratio between simultaneously recorded mean coronary occlusive pressure divided by mean aortic pressure, both subtracted by central venous pressure. Secondary study end points were fractional flow reserve during vessel patency, the quantitative intracoronary ECG ST-segment elevation, and angina pectoris during the same 1-minute coronary occlusion. Collateral flow index in the untreated RCA and left coronary artery changed from 0.071±0.082 at baseline to 0.132±0.117 (P<0.0001) at follow-up examination and from 0.106±0.092 to 0.081±0.079 (P=0.29), respectively. RCA fractional flow reserve increased significantly (P=0.0029) from baseline to follow-up examination, despite deferral of coronary intervention in all patients. There was a decrease in intracoronary ECG ST-elevation during RCA occlusion from baseline to follow-up examination (P=0.0015); it did not change in the left coronary artery. Angina pectoris during RCA occlusion tended to occur in fewer patients at follow-up versus baseline examination (P=0.06).

CONCLUSIONS

Permanent right internal mammary artery device closure seems to augment extracardiac ipsilateral coronary supply to the effect of reducing ischemia in the dependent myocardial region.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT02475408.

Association of Internal Mammary Artery Flow with Different Comorbidities and Post-Coronary Artery Bypass Graft Complications

Objective

The internal mammary artery (IMA) is commonly used arterial graft for coronary artery bypass surgery (CABG). The IMA has a better patency and survival. This study considers different comorbidities and conditions where IMA flow may be low. Therefore, the main objective is to determine the flow of IMA in different diseases, its relation to gender, age, and in different blood groups in order to prevent possible complications.

Methods

A prospective study was conducted at the Cardiac Surgery Unit, Civil Hospital Karachi from January 2013 to December 2015. The data of 158 patients who underwent primary, isolated, and CABG surgery was collected. Free flow of IMA was measured immediately after harvesting for 30 seconds within a syringe, and its relationship with different diseases and conditions was examined. Data was collected using a structured questionnaire from the patients' medical record files and it was later analyzed and entered into the Statistical Package for Social Sciences (SPSS) software, V17 (IBM SPSS Statistics, Armonk, NY).

Results

The mean flow was 11.6 ± 9.6 ml. There was no difference in flow related to gender, diabetes, smoking, renal disease, and chronic obstructive pulmonary disease (COPD). There was significantly higher flow in the age group of 50 to 60 years (p = 0.002), hypertensive patients (p = 0.016), patients with liver disease (p = 0.001), BMI > 30 (p = 0.041), and the blood group AB+ (p = 0.02). The atrial fibrillation and readmissions were higher in patients who had low flow. Low flow IMA, which was used on left anterior descending (LAD) artery stenosis patients, showed a significantly higher need of pharmacological and mechanical support.

Conclusion

IMA should be used carefully in patients where its flow is low; conditions must be analyzed where flow may be low to avoid complications. Further studies are warranted.

Decellularization of Human Internal Mammary Artery: Biomechanical Properties and Histopathological Evaluation

This study undertook to create small-diameter vascular grafts and assess their structure and mechanical properties to withstand arterial implantation. Twenty samples of intact human internal mammary arteries (IMAs) were collected and decellularized using detergent-based methods. To evaluate residual cellular and extracellular matrix (ECM) components, histological analysis was performed. Moreover, collagen typing and ECM structure were analyzed by Picrosirius red and Movat's pentachrome staining. Scanning electron microscopy was also applied to assess microarchitecture of both endothelial and adventitial surfaces of native and decellularized arterial samples. Furthermore, mechanical tests were performed to evaluate the rigidity and suture strength of the arteries. Human IMAs were completely decellularized in all three segments (proximal, middle, and distal). ECM proteins such as collagen and elastic fibers were efficiently preserved and no structural distortion in intima, media, and adventitial surfaces was observed. The parameters of the mechanical tests revealed no significant differences in the mechanical properties of decellularized arteries in comparison to native arteries with considerable strength, suture retention, and stress relaxation (Young's modulus [MPa] = 0.22 ± 0.023 [native] and 0.22 ± 0.015 [acellular]; and suture strength 0.56 ± 0.19 [native] vs. 0.56 ± 0.12 [acellular], respectively). Decellularized IMA represents a potential arterial scaffold as an alternative to autologous grafts for future arterial bypass surgeries. By this technique, microarchitecture and mechanical integrity of decellularized arteries were considerably similar to native arteries. The goal of this study was to introduce an efficient method for complete decellularization of human IMA and evaluate the ECM and biomechanical properties.

A side-hole catheter for catheterization of a difficult internal mammary artery

Background The internal mammary artery (IMA) can be a source of hemoptysis in patients with chronic lung disease. Intervention via the IMA can be a challenge due to anatomic variations and lead to excessive contrast use and radiation exposure. Purpose To evaluate safety and efficiency of a new side-hole catheter for the catheterization of the IMA in patients with hemoptysis. Material and Methods From January 2011 to August 2014, a total of 96 transarterial embolization procedures required exact evaluation of the IMA due to chronic lung disease involving the anterior thorax. In 17 cases (18%) of these 96 procedures, the conventional selective IMA angiography failed and instead a novel side-hole catheter as a modification of a cobra-type curved catheter was used. The side hole allowed passage of a micro-wire and catheter. Results Failed catheterizations were due to severe vascular tortuosity, acutely angulated subclavian artery, or abnormal takeoff of the IMA. The Cobra shaped catheter with the microcatheter through the side-hole catheter yielded a technical success rate of 100%. Longer time was required to catheterize the IMA with the Cobra shaped catheter than with the side-hole catheter (17 vs. 2 min, P < 0.05). There were no procedure-related complications. Conclusion Side-hole catheter technique is useful in patients whose internal mammary artery is difficult to access. Further design revisions are needed to improve the ease and speed of IMA catheterization and angiography.

Using a Single Internal Mammary Artery as Retrograde and Antegrade Flow for Bilateral Deep Inferior Epigastric Artery Perforator Reconstruction: A Case Report

Deep inferior epigastric artery perforator (DIEP) flaps have become an attractive option for autologous breast reconstruction. The internal mammary artery (IMA) is the usual artery of choice for reconstruction. Unfortunately, there are certain situations when the IMA may not be suitable for usage as in previous radiation or diminutive size. Several options have been documented, such as using the thoracodorsal vessels. In this case report, we report usage of the distal and proximal ends of a contralateral single mammary artery to supply antegrade and retrograde flow to bilateral DIEP flaps. With increasing complexity of patient populations, the use of alternate approaches to recipient vessel in DIEP reconstruction becomes essential for effective outcomes.

Histologic comparison between the internal mammary artery and the deep inferior epigastric artery and clinical implications for microsurgical breast reconstruction

BACKGROUND

The internal mammary artery (IMA) is one of the most popular recipients for microsurgical breast reconstruction. However, it is often separated into sleeve-like layers when it is handled. This study tried to explain this unique behaviour of the IMA through histologic observation.

METHODS

Nine pairs of IMAs and DIEAs were harvested and subject for haematoxylin-eosin and Verhoeff's elastic staining. Thickness of the tunica media and the number of elastic lamellae were compared. Samples of the IMA, the DIEA, and the thoracodorsal artery from another patient were observed through the transmission electron microscope to further show the structural differences.

RESULTS

The most notable difference was presence of multiple elastic lamellae in tunica media in the IMAs, which was barely present in the DIEAs. The mean number of elastic lamellae was 9.2 in the IMA group and 1.0 in the DIEA group (p < 10(-9)). A transmission electron microscope showed that the tunica media of the DIEA and the TDA was densely packed with smooth muscle cells, while the muscle cells distributed sparsely in the IMA.

CONCLUSIONS

The IMA is an elastic artery which is characterised by multiple layers of elastic lamellae while relatively lacking in smooth muscle cells. The wall of the IMA is easily dissected between the tunica media and the adventitia, or at the outer 1/3 of the tunica media. The inner structure is easily torn if microsutures do not engage the tunica adventitia.

Arterial territory-specific phosphorylated retinoblastoma protein species and CDK2 promote differences in the vascular smooth muscle cell response to mitogens

Despite recent advances in medical procedures, cardiovascular disease remains a clinical challenge and the leading cause of mortality in the western world. The condition causes progressive smooth muscle cell (SMC) dedifferentiation, proliferation, and migration that contribute to vascular restenosis. The incidence of disease of the internal mammary artery (IMA), however, is much lower than in nearly all other arteries. The etiology of this IMA disease resistance is not well understood. Here, using paired primary IMA and coronary artery SMCs, serum stimulation, siRNA knockdowns, and verifications in porcine vessels in vivo, we investigate the molecular mechanisms that could account for this increased disease resistance of internal mammary SMCs. We show that the residue-specific phosphorylation profile of the retinoblastoma tumor suppressor protein (Rb) appears to differ significantly between IMA and coronary artery SMCs in cultured human cells. We also report that the differential profile of Rb phosphorylation may follow as a consequence of differences in the content of cyclin-dependent kinase 2 (CDK2) and the CDK4 phosphorylation inhibitor p15. Finally, we present evidence that siRNA-mediated CDK2 knockdown alters the profile of Rb phosphorylation in coronary artery SMCs, as well as the proliferative response of these cells to mitogenic stimulation. The intrinsic functional and protein composition specificity of the SMCs population in the coronary artery may contribute to the increased prevalence of restenosis and atherosclerosis in the coronary arteries as compared with the internal mammary arteries.

Clinical and angiographic results after hybrid coronary revascularization

BACKGROUND

With hybrid coronary revascularization (HCR), minimally invasive left internal mammary artery (LIMA) to left anterior descending coronary artery (LAD) grafting is combined with percutaneous coronary intervention (PCI) of non-LAD vessels. The purpose of this study was to examine the short-term clinical and angiographic results in one of the largest HCR series to date.

METHODS

From 2003 to 2012, 300 consecutive patients (aged 64±12 years, female 31.7%, predicted risk of mortality 1.6%±2.1%) underwent HCR on an intent-to-treat basis at a single institution. After robotic or thoracoscopic LIMA harvest, off-pump LIMA to LAD grafting was performed through a 3- to 4-cm sternal-sparing, non-rib-spreading thoracotomy. PCI was utilized to treat non-LAD lesions either before, after, or concomitant with the surgical procedure.

RESULTS

Of the 300 patients undergoing HCR on an intent-to-treat basis, HCR was performed with surgery first in 192 patients (64.0%), PCI first in 56 (18.7%), and as a concomitant procedure in 21 (7.0%). Of the 31 patients (10.1%) who did not undergo HCR, 24 patients (8.0%) did not have PCI and thus were incompletely revascularized. For all patients, 30-day mortality, stroke, and nonfatal myocardial infarction occurred in 4 (1.3%), 3 (1.0%), and 4 (1.3%), respectively. Angiographic LIMA evaluation was performed in 248 patients and revealed a FitzGibbon A LIMA patency rate of 97.6% (242 of 248 patients). Repeat revascularization was required in 13 of 300 patients (4.3%).

CONCLUSIONS

Hybrid coronary revascularization represents an alternative approach for patients with multivessel coronary disease with excellent short-term outcomes. It provides a minimally invasive alternative to traditional coronary artery bypass graft surgery and may prove more durable than multivessel PCI.

Arterial grafts balance survival between incomplete and complete revascularization: a series of 1000 consecutive coronary artery bypass graft patients with 98% arterial grafts

OBJECTIVE

Coronary artery bypass grafting (CABG) with incomplete revascularization (ICR) is thought to decrease survival. We studied the survival of patients with ICR undergoing total arterial grafting.

METHODS

In a consecutive series of all-comer 1000 patients with isolated CABG, operative and midterm survival were assessed for patients undergoing complete versus ICR, with odds ratios and hazard ratios, adjusted for European System for Cardiac Operative Risk Evaluation category, CABG urgency, age, and comorbidities.

RESULTS

In this series of 1000 patients with 98% arterial grafts (2922 arterial, 59 vein grafts), 73% of patients with multivessel disease received bilateral internal mammary artery grafts. ICR occurred in 140 patients (14%). Operative mortality was 3.8% overall, 8.6% for patients with ICR, and 3.2% for patients with complete revascularization (P = .008). For operative mortality using multivariable logistic regression, after controlling for European System for Cardiac Operative Risk Evaluation category (P < .001) and CABG urgency (P = .03), there was no evidence of a statistically significant increased risk of death due to ICR (odds ratio, 1.73; 95% confidence interval, 0.80-3.77). For midterm follow-up (median, 54 months [interquartile range, 27-85 months]), after controlling for European System for Cardiac Operative Risk Evaluation category (P < .001) and comorbidities (P = .017) there was a significant interaction between age ≥ 80 years and ICR (P = .017) in predicting mortality. The adjusted hazard ratio associated with ICR for patients older than age 80 years was 5.7 (95% confidence interval, 1.8-18.0) versus 1.2 (95% confidence interval, 0.7-2.1) for younger patients.

CONCLUSIONS

This is the first study to suggest that ICR in patients with mostly arterial grafts is not associated with decreased survival perioperatively and at midterm in patients younger than age 80 years. Arterial grafting, because of longevity, may balance survival between complete revascularization and ICR.

Adoption and effectiveness of internal mammary artery grafting in coronary artery bypass surgery among Medicare beneficiaries

OBJECTIVES

The aim of this study was to assess the pattern of the adoption of internal mammary artery (IMA) grafting in the United States, test its association with clinical outcomes, and assess whether its effectiveness differs in key clinical subgroups.

BACKGROUND

The effect of IMA grafting on major clinical outcomes has never been tested in a large randomized trial, yet it is now a quality standard for coronary artery bypass graft (CABG) surgery.

METHODS

We identified Medicare beneficiaries ≥66 years of age who underwent isolated multivessel CABG between 1988 and 2008, and we documented patterns of IMA use over time. We used a multivariable propensity score to match patients with and without an IMA and compared rates of death, myocardial infarction (MI), and repeat revascularization. We tested for variations in IMA effectiveness with treatment × covariate interaction tests.

RESULTS

The IMA use in CABG rose slowly from 31% in 1988 to 91% in 2008, with persistent wide geographic variations. Among 60,896 propensity score-matched patients over a median 6.8-year follow-up, IMA use was associated with lower all-cause mortality (adjusted hazard ratio: 0.77, p < 0.001), lower death or MI (adjusted hazard ratio: 0.77, p < 0.001), and fewer repeat revascularizations over 5 years (8% vs. 9%, p < 0.001). The association between IMA use and lower mortality was significantly weaker (p ≤ 0.008) for older patients, women, and patients with diabetes or peripheral arterial disease.

CONCLUSIONS

Internal mammary artery grafting was adopted slowly and still shows substantial geographic variation. IMA use is associated with lower rates of death, MI, and repeat coronary revascularization.

How I choose conduits and configure grafts for my patients-rationales and practices

Coronary artery bypass grafting (CABG) continues to be an effective therapy for many patients with lasting long-term durability and consistent outcomes, despite the development of percutaneous revascularization. The long-term outcome for surgical revascularization depends on multiple variables, including the choice of conduits. However, the choice of coronary conduits has been studied and debated for decades now. In this review article, we examined the current evidences and described our choice on coronary conduits and grafting strategies at our medical center.

Fractional flow reserve-guided coronary artery bypass grafting: can intraoperative physiologic imaging guide decision making?

OBJECTIVES

Fractional flow reserve-guided coronary artery bypass grafting is emerging in cardiac surgery, in which the nature (anatomic and functional characteristics) of the target vessel epicardial coronary artery stenosis is important in graft site selection. The nature of the stenosis might determine a different physiologic response to bypass grafting. We report our recent experience using near infrared fluorescence complex angiography and perfusion analysis to identify the nature of stenoses in the target vessel by imaging the physiologic response to grafting.

METHODS

In 167 patients who underwent consecutive multivessel coronary artery bypass grafting cases (63% off-pump coronary artery bypass grafting) with traditional anatomy-based revascularization, we imaged and analyzed 359 grafts (53% arterial). This platform provides angiographic data of both the target vessel epicardial coronary artery and graft simultaneously (to assess the imaged competitive flow); and because a change in fluorescence intensity is proportional to the change in blood flow and perfusion, the quantified change (if any) in regional myocardial perfusion surrounding the grafted target vessel epicardial coronary artery.

RESULTS

The patient outcomes in our series were excellent. All 359 grafts were widely patent by angiography, and 24% of the arterial and 22% of the saphenous vein grafts showed no regional myocardial perfusion change in response to bypass grafting. In 165 in situ internal mammary artery grafts to the left anterior descending artery (>70% stenosis), 40 had no change in regional myocardial perfusion, and 32 of the 40 had competitive flow imaged.

CONCLUSIONS

An important number of angiographically patent bypass grafts demonstrated no change in regional myocardial perfusion, suggesting anatomic, but nonfunctional, stenoses in those target vessel epicardial coronary arteries. In in situ arterial grafts, imaged competitive flow is associated with nonfunctional stenoses in the target vessel epicardial coronary artery. Imaging these physiologic responses to target vessel revascularization might be useful in the emerging fractional flow reserve-guided era.

Impact of lipid-lowering medications and low-density lipoprotein levels on 1-year clinical outcomes after coronary artery bypass grafting

BACKGROUND

Studies investigating lipid-lowering medication (LLM) use and LDL levels in coronary artery bypass grafting patients are limited.

STUDY DESIGN

The Veterans Affairs Randomized On/Off Bypass Trial's patient records were analyzed for LLM use and 1-year LDL levels. Mortality, acute MI (AMI), and repeat revascularization rates were compared at 1 year between patients with and without LLM at discharge. In addition, AMI, repeat revascularization, and graft patency were compared between patients that did and did not achieve a 1-year LDL target level of <100 mg/dL.

RESULTS

The LLM data were available for 86.4% (1,904 of 2,203) of patients. Rates of LLM use were 83.4% (1,316 of 1,577) at discharge and 90.0% (1,713 of 1,904) at 1 year. Patients discharged after coronary artery bypass grafting on LLMs had a significantly lower 1-year mortality rate (1.9% vs 5.4%; p < 0.01) than those not discharged on LLM, and 1-year AMI and repeat revascularization rates were not significantly different. Of the patients with 1-year LDL measurements, 69.4% (1,200 of 1,729) achieved an LDL target level of <100 mg/dL. No differences were seen in AMI, revascularization, or graft occlusion rates between patients who achieved target LDL levels and those who did not.

CONCLUSIONS

Rates of LLM use among veterans post-coronary artery bypass grafting are high. Discharge on LLM might be associated with improved intermediate-term survival. Patients who achieved an LDL target of <100 mg/dL at 1-year did not experience improved 1-year clinical outcomes or graft patency. Longer-term follow-up might reveal differences in cardiac outcomes related to achievement of target LDL levels.

Elevation of miR-221 and -222 in the internal mammary arteries of diabetic subjects and normalization with metformin

Diabetes is a major risk factor for cardiovascular disease and is associated with increased intimal thickening and accelerated vascular smooth muscle cell (VSMC) proliferation. We measured the expression of two microRNAs that promote intimal thickening, miR-221/222, and mRNA encoding a downstream target, p27(Kip1), in internal mammary artery (IMA) segments collected from 37 subjects undergoing coronary artery bypass grafting. The segments were stratified into three groups: non-diabetic subjects (ND), diabetic subjects not on metformin (DMMet-), and diabetic subjects on metformin (DMMet+). The DMMet- group exhibited a significant increase in miR-221/222 and decrease in p27(Kip1) mRNA compared to both the ND and DMMet+ groups. miR-221/222 levels inversely correlated with metformin dose. VSMCs isolated from the IMAs of the DMMet- group proliferate at a faster rate than those of the ND and DMMet+ groups. Further studies into the importance of miR-221/222 in the increased intimal thickening observed in diabetic subjects is warranted.

The history of arterial revascularization: from Kolesov to Tector and beyond

Coronary artery bypass grafting (CABG) is the one of the most effective revascularization strategies for patients with obstructive coronary artery disease. Total arterial revascularization using one or both internal thoracic and radial arteries has been shown to improve early outcomes and reduce long-term cardiovascular morbidity. Although CABG has evolved from an experimental procedure in the early 1900's to become one of the most commonly performed surgical procedures, there is still significant variation in grafting strategies amongst surgeons. We review the history and development of CABG with a particular emphasis on the early pioneers and the evolution of arterial grafting.

Total Arterial Off-pump Coronary Revascularization with a Bilateral Internal Mammary Artery Y Graft (208 cases)

Objective:

The aim was to evaluate the early outcome of off-pump coronary artery bypass grafting (OPCABG) with a bilateral internal mammary artery (BIMA) Y configuration graft to achieve total arterial myocardial revascularization.

Materials and Methods:

From October 2002 to December 2008, 208 patients (196 male and 12 female patients) underwent OPCABG by only using a BIMA Y configuration graft. The average age of the patients was 56.5±11.3 years, with the age range being 33–78 years. A total of 167 (80.2%) cases had triple-vessel disease. Left main stem disease was found in 33 (15.9%) cases, and double-vessel disease was found in 8 (3.9%) cases. The semiskeletonization skill was used to harvest the two IMAs, and then the free right internal mammary artery was anastomosed end-to-side to the in situ left internal mammary artery to composite a Y configuration graft. Off-pump and sequential anastomosis methods were used to perform coronary artery bypass surgery for the patients. Graft patency was assessed by using the HT311 transit time flowmeter (USA Transonic Systems Inc.), intraoperatively.

Results:

We performed distal anastomoses of the grafts in 728 patients, the average being 3.5±1.3 per person. No one died and got recurrent angina within 30 days after operation.

Conclusion:

OPCABG by using the BIMA Y graft was safe and effective to achieve total arterial revascularization, and avoid surgical operation on the ascending aorta, and other incisions.

Clampless off-pump surgery reduces stroke in patients with left main disease

BACKGROUND

Surgical revascularization is the most appropriate therapy for patients with significant left main coronary-artery disease (LMD). An incidence of perioperative stroke remains an issue when compared to the early outcomes to percutaneous coronary intervention (PCI). This study evaluates the safety and impact of standardized "clampless" OPCAB techniques, composed of either complete in situ grafting or "clampless" device enabled techniques for stroke reduction in patients undergoing surgical revascularization for LMD.

METHODS

Between 1999 and 2009, 1031 patients with LMD underwent myocardial-revascularization at our institution. Of these, 507 patients underwent "clampless" OPCAB and 524 patients underwent conventional on-pump CABG (ONCABG). Data-collection was performed prospectively and a propensity-adjusted regression-analysis was applied to balance patient characteristics. LMD was defined as a stenosis >50% and endpoints were mortality, stroke, a cardiac-composite (including death, stroke and myocardial-infarction); a non-cardiac composite and complete-revascularization.

RESULTS

In OPCAB patients, the cardiac composite (3.0% vs. 7.8%; propensity-adjusted (PA)OR=0.27; CI95% 0.12-0.65; p=0.003) as well as the occurrence of stroke (0.4% vs. 2.9%; PAOR=0.04; CI95% 0.003-0.48; p=0.012) were significantly lower while the mortality-rate was well comparable between groups (1.8% vs. 2.5%; PAOR=0.44; CI95% 0.11-1.71; p=0.24). The non-cardiac composite was also significantly decreased after OPCAB (8.9% vs. 19.7%; PAOR=0.55; CI95% 0.34-0.89; p=0.014) and complete revascularization was achieved for similar proportions in both groups (95.1% vs. 93.7%; p=0.35).

CONCLUSIONS

This study shows the superiority of OPCAB for patients with LMD with regards to risk-adjusted outcomes other than mortality. A "clampless OPCAB strategy", effectively reduces stroke yielding similar early outcomes as PCI.

Role of gender, smoking profile, hypertension, and diabetes on saphenous vein and internal mammary artery endothelial relaxation in patients with coronary artery bypass grafting

The aim of this study was to investigate if there was a link between the relaxant responses in saphenous vein (SV) and internal mammary artery (IMA) segments obtained from patients undergoing coronary artery bypass grafting and the patients' cardiovascular risk factors. Endothelium-(in)dependent relaxations were assessed by isometric tension studies. Endothelium-dependent relaxant responses were greater in IMA than SV and gender, smoking profile and history of hypertension but not diabetes appeared to have an influence on these responses. Endothelium-dependent relaxant responses in both IMA and SV were greater in males than females and relaxant responses in IMA segments were attenuated in smokers, whereas the opposite effect was noted in SV segments. Endothelium-dependent relaxant responses in SV were lower in patients with hypertension. Endothelium-independent relaxant responses were greater in IMA than SV. Endothelium-independent responses were greater in male patients' SV segments, but gender played no role in IMA segments. Diabetes had no effect on endothelium-independent responses in IMA, but SV segments from diabetic patients had greater responses. Neither conduit's endothelium-independent response was affected by hypertensive status. The relationship between risk factor status and endothelial responses is multifactorial, with gender, hypertension, diabetes and smoking status all contributing.