Congenital Absence of Pericardium: A Case Report and Technical Considerations in Cardiac Surgery

This case report describes a rare instance of left-sided congenital pericardial agenesis (CPA) encountered during coronary artery bypass grafting (CABG) in a 77-year-old male. In this unique case, the presence of an unusual strip of left pericardium containing the phrenic nerve posed significant surgical challenges. Special attention was required for the graft lay, ensuring adequate filling of the heart during assessment before closure, as well as emphasis on the need for generous graft length. Additionally, the evaluation of graft positioning prior to cardiopulmonary bypass was crucial. Despite these complexities, CABG was successfully performed with no complications to note. This case underscores the importance of adaptability in surgical technique to manage the unique challenges posed by CPA, leading to a positive outcome despite the atypical cardiac anatomy.

Bilateral versus Single Internal Thoracic Artery Grafting Strategies Supplemented by Radial Artery Grafting

PURPOSE

It is unclear if a second or third arterial graft can improve clinical outcomes in coronary artery bypass graft surgery. We compared the outcomes of bilateral internal thoracic artery (BITA) plus radial artery (RA) grafting versus left internal thoracic artery (LITA) plus RA grafting after off-pump coronary artery bypass grafting.

MATERIALS AND METHODS

Between January 2009 and December 2020, a total of 3007 patients with three-vessel coronary artery disease who underwent off-pump coronary artery bypass were analyzed. Among them, 971 patients received total arterial grafting using LITA. We divided the patients into two groups [group A, BITA+RA grafting (n=227) and group B, LITA+RA grafting (n=744)], and compared the survival and major adverse cardiac and cerebrovascular event (MACCE) rates between the two groups at 10 years.

RESULTS

After risk adjustment with inverse probability treatment weighting methods, the freedom from all-cause mortality was 93.1% and 88.3% in groups A and B, respectively (p=0.140). The freedom from MACCE rates were 68.3% and 89.0%, respectively (p<0.0001). LITA plus RA grafting [hazard ratio (HR): 1.3, 95% confidence interval (CI): 1.05-2.37, p=0.025] and incomplete revascularization (HR 1.2, 95% CI: 0.70-2.15, p=0.046) were significant risk factors for MACCEs in multivariable Cox regression analysis.

CONCLUSION

The rates of MACCEs were lower with LITA plus RA grafting than with BITA plus RA grafting in total arterial revascularization. Furthermore, complete revascularization improved long-term outcomes following total arterial grafting.

Left or bilateral internal mammary artery employment in coronary artery bypass grafting: midterm results

BACKGROUND

The gold standard for coronary artery bypass grafting to the left anterior descending artery is use of the left internal mammary artery. Better long-term survival has been reported using bilateral internal mammary arteries compared to left internal mammary artery only, but many surgeons are reluctant to employ bilateral internal mammary arteries in coronary artery bypass grafting. This study aimed to evaluate the effectiveness and safety of bilateral internal mammary artery use.

METHODS

From 2014 to 2017, 1703 patients underwent coronary artery bypass grafting in our institute. Of these, 772 met the inclusion criteria and were randomly assigned to receive bilateral (n = 387) or left (n = 385) internal mammary artery grafts. The mean age was 67.1 ± 6.0 years (range 48-85 years) and 474 (61.4%) were male. The mean number of diseased vessels was 3.1 ± 0.9, and mean EuroSCORE II was 3.4% ± 1.1%.

RESULTS

Hospital mortality was 1.2% in the left internal mammary artery group vs. 1.8% in the bilateral internal mammary artery group (p = 0.55). There was no difference in procedure-related complications between groups. Mean follow-up was 65.9 months. Survival in the bilateral internal mammary artery group at 1, 3, and 5 years was 98.7%, 98.7%, and 94.8% vs. 98.1%, 98.1%, and 90.9%, respectively, in the left internal mammary artery group (p = 0.63).

CONCLUSION

Application of bilateral internal mammary arteries in coronary artery bypass grafting is safe and effective, with comparable midterm results to those with the left internal mammary artery only.

Branched internal mammary conduit permits non-sequenced total arterial revascularization

Recent trends in cardiac surgery have encouraged total arterial coronary revascularization, citing advantages in long-term patency and overall mortality. Often relying on sequenced, composite, and free-graft strategies, total arterial coronary revascularization is limited by conduit availability and surgical complexity. We present the use of bilateral internal mammary artery grafts to achieve nonsequential 3-vessel total arterial coronary revascularization using the preserved distal bifurcation of the right internal mammary artery. Utilization of distal internal mammary artery branches should be considered a viable strategy in select patients and can broaden the opportunities for total arterial coronary revascularization in patients with multivessel coronary disease.

Coronary-coronary bypass grafting: artery or vein?

BACKGROUND

The method of coronary-coronary bypass grafting was described in 1987 but has not been widely used, and there are only a few studies that report good short-term and mid-term results as well as some individual cases of long-term follow-up. In our medical institution, we carried out an analysis of the long-term results of coronary-coronary bypass grafting, which are presented in this study.

METHODS

This was a retrospective single-center study on 95 patients who underwent coronary-coronary bypass grafting as a supplement to the standard coronary bypass grafting procedure. All patients underwent angiographic assessment of the coronary bypass grafts during the long-term follow-up period. The observation period was up to 123 months. Angiographic assessment of 109 coronary-coronary grafts was carried out.

RESULTS

Twelve (7.6%) arterial and 11 (19.3%) venous conduits were found to be occluded, and 8 (10.3%) arterial and 10 (31.3%) venous coronary-coronary grafts were occluded during the observation period.

CONCLUSION

Arterial coronary-coronary artery bypass grafting represents an alternative technique that allows complete myocardial revascularization.

Internal thoracic artery harvesting with a LigaSure device

Use of the internal thoracic artery is the gold standard for coronary bypass surgery. Bilateral internal thoracic artery use is encouraged, especially in young patients. There are various techniques of harvesting. The LigaSure device has been used successfully as a low heat generating electrothermal vessel sealer in laparoscopic and open surgery for a long time. An internal thoracic artery harvesting technique is described, using a LigaSure Maryland Jaw 23-cm open sealer/divider through a thoracotomy and LigaSure Exact Dissector through a sternotomy. LigaSure devices can be used for pedicled or skeletonized internal thoracic artery harvesting with almost equal precision and safety.

Antegrade filling of mammary graft by inappropriately revascularized artery

A 57-year-old man underwent multiple-arterial revascularization including a sequential left internal mammary artery graft to the diagonal branch and left anterior descending coronary artery. Twenty-one months later, repeat angiography due to a new onset of chest discomfort confirmed string sign and nonfunctional proximal left internal mammary artery, and antegrade filling of the distal leg of the sequential graft and the left anterior descending artery through the diagonal branch. This is a known but uncommon angiographic finding that confirms the importance of eventual competitive flow.

Coronary artery surgery in a patient with grossly emphysematous lung

The pedicled left internal thoracic artery graft is the mandatory conduit in coronary artery bypass surgery. A grossly emphysematous lung may sometimes present a significant problem for positioning of the pedicled left internal thoracic artery conduit. An inverted pedicled left internal thoracic artery graft (internal thoracic artery transected near its origin, thus supplied by retrograde flow from superior epigastric and musculophrenic arteries) might occasionally be the conduit of choice for those patients.

Which is the best graft for the right coronary artery?

Bilateral internal mammary arteries directed to the left coronaries are gaining popularity; an increasing level of evidence nowadays supports this surgical strategy. On the other hand, composite right internal mammary artery, radial artery, and gastroepiploic artery targeting high-grade stenotic lesions in the right coronary artery system may confer improved mid- and long-term patency compared to long saphenous veins. This analysis looks into the evidence comparing data of the third best available conduit for grafting the right coronary artery, and by extrapolating this report, compares total arterial revascularization vs. conventional coronary artery bypass grafting.

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.

Surgical approach to aortic valve replacement after previous bilateral internal thoracic artery grafting

The authors present a manubrium-sparing sternotomy technique for aortic valve replacement in patients who have undergone previous myocardial revascularization with both internal thoracic arteries. They have found that preoperative 64-multislice computed tomographic imaging facilitates surgical planning by delineating the course of patent grafts and, in particular, the relationship between the sternum and the right internal thoracic artery graft. A manubrium-sparing sternotomy can in such instances avoid injury to the right internal thoracic artery graft during both resternotomy and adhesion dissection, thus reducing surgical risk and operative time.

Hybrid coronary revascularization in high-risk patients

From January 2002 through June 2004, 17 patients (2% of all coronary cases) were treated with off-pump coronary artery bypass grafting combined with percutaneous coronary intervention. There were 13 men and 4 women, whose ages ranged from 54 to 78 years (mean, 63.1 +/- 20.9 yr). Preoperative angiography revealed 2-vessel coronary artery disease in 12 patients and 3-vessel disease in the remaining 5 patients. In all patients, extensive lesions (>50%) in the circumflex and right coronary arteries were treated first with a percutaneous intervention, followed by beating-heart coronary artery bypass grafting within 3 hours to treat the remaining obstructed vessels. Coronary angiography was performed 12 months after the operation to evaluate the effectiveness of the procedure. Procedure-related complications did not occur, and there was no in-hospital death. All patients underwent a successful left internal mammary artery-left anterior descending artery anastomosis with the exception of 1 patient, in whom we used a saphenous vein because of previous chest radiotherapy. The postoperative courses were uneventful, and no deterioration of preoperative organ dysfunction was noticed in any patient. There was no cardiac-related death or myocardial infarction. In follow-up angiography, all left internal mammary artery-left anterior descending artery anastomoses were patent. Three patients with restenosis were treated medically, which resulted in substantial reduction of angina. Hybrid coronary revascularization enables complete revascularization and may be an alternative method of treating selected patients who have concomitant disease.

Effects of pleurotomy on respiratory sequelae after internal mammary artery harvesting

The preservation of pleural integrity during mammary artery harvesting may decrease atelectasis and pleural effusion during the postoperative period. We designed this retrospective study to evaluate the effects on postoperative pulmonary function of pleural integrity versus opened pleura, in patients who receive a left internal mammary artery graft. The study group consisted of 1141 patients who underwent elective coronary artery bypass grafting. The patients were retrospectively evaluated and divided into 2 groups: those who underwent internal mammary artery harvesting with opened pleura (n=873) or with pleural integrity (n=268). To monitor pleural effusion and atelectasis, chest radiography was performed routinely 1 day before operation and on the 2nd, 5th, and 7th postoperative days. The preoperative, after extubation, and 1st postoperative day values of partial oxygen pressure (PaO2), partial carbon dioxide pressure (PaCO2), and oxygen (O2) saturation were recorded for comparison, as was the hematocrit. The mean age of the patients was 574 +/- 8.81 years. There were no significant differences between the groups in mean values of PaO2, PaCO2, O2 saturation, and hematocrit after extubation or on the 1st postoperative day. Atelectasis on the 5th and 7th postoperative days, pleural effusion on the 2nd, 5th, and 7th days, and postoperative bleeding were significantly less in the group with preserved pleural integrity. We showed that preservation of pleural integrity during internal mammary artery harvesting decreases postoperative bleeding, pleural effusion, and atelectasis. We conclude that preservation of pleural integrity, when possible, can decrease these postoperative complications of coronary artery bypass grafting.

Arterial conduits should be evaluated preoperatively in coronary artery bypass patients with pseudoxanthoma elasticum

A 74-year-old man who had pseudoxanthoma elasticum presented with unstable angina and underwent urgent coronary artery bypass grafting. Preoperative angiography did not include the internal mammary arteries. Intraoperatively, the left internal mammary artery was found to be diseased and could not be used. This case lends support to the need for thorough preoperative evaluation, including angiography, of potential arterial conduits in patients with pseudoxanthoma elasticum.

Effects of previously well-developed collateral vessels on left internal mammary artery graft flow after bypass surgery

Transthoracic Doppler ultrasonography can assess left internal mammary artery patency and flow after coronary artery bypass grafting. We aimed to show, by transthoracic Doppler ultrasonography, the early effects upon left internal mammary artery graft flow of preoperative collateral vessels supplying the left anterior descending artery. Thirty-four consecutive patients undergoing coronary artery bypass were prospectively enrolled: 19 patients with collateral vessels supplying the left anterior descending were compared with 15 patients without collaterals. After bypass, end-diastolic velocity, mean velocity, flow volume, and ejection fraction were significantly greater, and the resistivity index was lower in patients with collateral vessels. The changes in velocities, volume, resistivity index, and pulsatility index were also found to be greater in patients with collateral vessels than in those without collaterals. Collateral vessels were the only factor affecting the changes in end-diastolic volume, mean velocity, flow volume, and resistivity index in multivariate analysis. Three factors affected postoperative left ventricular ejection fraction: collateral vessels, preoperative ejection fraction, and changes in left internal mammary flow volume. We conclude that patients with well-developed collaterals to the left anterior descending have better flow in the left internal mammary graft and more significant improvement in left ventricular function after coronary bypass. The flow volume of the mammary graft and the improvement of ventricular systolic functions after coronary bypass might be presumed with the presence of grade 2 or 3 preoperative collateral vessels.