Fractional flow reserve measured via left internal mammary artery after coronary artery bypass grafting:Two case reports

BACKGROUND The fractional flow reserve(FFR)has made the treatment of coronary heart disease more precise.However,there are few reports on the measurement of FFR via the left internal mammary artery(LIMA).Herein,we described the determination of further treatments by measuring FFR via the LIMA in 2 cases after coronary artery bypass grafting(CABG).CASE SUMMARY Case 1 was a 66-year-old male who was admitted due to“chest tightness after CABG.”The patient underwent CABG 7 years prior due to coronary heart disease.Coronary artery angiography showed complete occlusion of the left anterior descending artery(LAD),and subtotal occlusion of the third segment of the right coronary artery.On arterial angiography,there was 85%stenosis at the distal end of the anastomosis of the LIMA-LAD graft.FFR via LIMA was determined at 0.75.Thus,balloon dilation was performed in Case 1.FFR after balloon dilation was 0.94.Case 2 was a 60-year-old male who was admitted due to“chest tightness after CABG.”The patient underwent CABG 6 years prior due to coronary heart disease.There was 60%segmental stenosis in the middle segment of LAD and 75%anastomotic stenosis.FFR measured via LIMA was 0.83(negative);thus the intervention was not performed.Case 2 was given drug treatments.At the 3-mo follow-up,there was no recurrence of chest tightness or shortness of breath in both cases.They are currently under continual follow-up.CONCLUSION We provided evidence that FFR measurement via grafted blood vessels,especially LIMA,after CABG is a good method to determine the intervention course.

Off-pump sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system

Background Off-pump coronary artery bypass surgery （OPCAB） has been widely applied in recent years as a less invasive method of myocardial revascularization. This study evaluated the sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system during OPCAB.Methods From April 2004 to August 2010, patients with diffuse right coronary lesions were studied retrospectively and divided into two groups. Group 1 included seventeen patients who underwent this surgery while group 2 included twenty-one patients without right coronary artery surgical therapy. All patients presented with symptoms of angina. Blood flow of bridged vessels was measured. The perioperative ventricular parameters including left ventricular ejection fraction and end diastolic diameter were compared. During follow-up, myocardial nuclide imaging and coronary angiography were carried out.Results Off-pump coronary artery bypass was performed with an average of 3.6 grafts per patient. Hospital mortality was zero. At the time of follow-up, the patients in group 1 recovered better than in group 2 （P〈0.05）. In both groups, the mean New York Heart Association （NYHA） class and ejection fraction increased significantly （P〈0.001） and the mean left ventricular end-diastolic diameter decreased significantly （P 〈0.05）. Myocardial blood supply of inferior wall in group 1 was obviously improved by myocardial nuclide imaging. Coronary angiography for eight patients in group 1 verified that there was blood flow to myocardium in the arterialized vein.Conclusions Sequential bilateral internal mammary artery grafting combined with selective arterialization of the coronary venous system can be performed during OPCAB. A postoperative improvement in the cardiac functions and the quality of life was documented, increasing our expectation for extensive application.

Flexible Subclavian Artery Closure for an Inadvertent Injury to the Internal Mammary Artery During Internal Jugular Vein Catheterization

Central vein catheter （CVC） placement, which is widely utilized in clinical departments, is also highly important in preoperative preparations for radiofrequency catheter ablation （RFCA）. The internal jugular vein or subclavian vein is the routine target. Arterial injury is not uncommon during the procedure but is potentially devastating in spite of the safety and advantages of the Seldinger technique. Compressing of the airway by a hematoma, as well as hemothorax, pseudoaneurysm, arteriovenous fistula, stroke, and even death, has been well-described.

Semi-skeletonized Internal Mammary Grafts and Phrenic Nerve Injury:Cause-and-effect analysis

Summary： Phrenic nerve injury after cardiac surgery increases postoperative pulmonary complications. The purpose of this study was to analyze the causes and effects of phrenic nerve injury after cardiac surgery. Prospectively collected data on 2084 consecutive patients who underwent cardiac surgery from Jan. 1995 to Feb. 2002 were analyzed. Twenty-eight preoperative and operation related variables were subjected to logistic analysis with the end point being phrenic nerve injury. Then phrenic nerve injury and 6 perioperative morbidities were included in the analysis as variables to determine their independent predictive value for perioperative pulmonary morbidity. An identical approach was used to identify the independent risk factors for perioperative mortality. There were 53 phrenic nerve injuries （2.5 %）. There was no phrenic nerve injury in non-coronary surgery or coronary surgery using conduits other than the internal mammary artery. The independent risk factors for phrenic nerve injury were the use of internal mammary artery （Odds ratio （OR）=14.5） and the presence of chronic obstructive pulmonary disease （OR=2.9）. Phrenic nerve injury was an independent risk factor （OR=8.1） for perioperative pulmonary morbidities but not for perioperative mortality. Use of semi-skeletonized internal mammary artery harvesting technique and drawing attention to possible vascular or mechanical causes of phrenic nerve injury may reduce its occurrence. Unilateral phrenic nerve injury, although rarely life-threatening, is an independent risk factor for postoperative respiratory complications. When harvesting internal mammary arteries, it should be kept in mind avoiding stretching, compromising, or inadvertently dissecting phrenic nerve is as important as avoiding damage of internal mammary artery itself.

Bilateral vs unilateral internal mammary revascularization in patients with left ventricular dysfunction

AIM To investigate the survival benefit of bilateral internal mammary artery(BIMA) grafts in patients with left ventricular dysfunction.METHODS Between 1996 and 2009,we performed elective,isolated,primary,multiple cardiac arterial bypass grafting in 430 consecutive patients with left ventricular ejection fraction ≤ 40%. The early and long-term results were compared between 167 patients undergoing BIMA grafting and 263 patients using left internal mammary artery(LIMA)-saphenous venous grafting(SVG).RESULTS The mean age of the overall population was 60.1 ± 15 years. In-hospital mortality was not different between the two groups(7.8% vs 10.3%,P = 0.49). Early postoperative morbidity included myocardial infarction(4.2% vs 3.8%,P = 0.80),stroke(1.2% vs 3.8%,P = 0.14),and mediastinitis(5.3% vs 2.3%,P = 0.11). At 8-year follow-up,Kaplan-Meier-estimated survival(74.2% vs 58.9%,P = 0.02) and Kaplan-Meier-estimated event-free survival(all cause deaths,myocardial infarction,stroke,target vessel revascularization,heart failure)(61.7% and 41.1%,P < 0.01) were significantly higher in the BIMA group compared with the LIMA-SVG group in univariate analysis. The propensity score matching analysis confirmed that BIMA grafting is a safe revascularization procedure but there was no long term survival(P = 0.40) and event-free survival(P = 0.13) in comparison with LIMA-SVG use.CONCLUSION Our longitudinal analysis suggests that BIMA grafting can be performed with acceptable perioperative mortality in patients with left ventricular dysfunction.

Prevention of Sternal Dehiscence Following Use of Bilateral Internal Mammary Arteries in OPCAB

Purpose: We harvested bilateral Internal Mammary Arteries and made LIMA-RIMA Y in all the patients undergoing OPCAB at our center irrespective of the presence or absence of various risk factors for sternal dehiscence. The purpose of this study was to find an effective way of sternal closure in patients undergoing OPCAB with both the Internal Mammary Arteries harvested for grafting. Method: The patients who did not have any risk factors were placed in group I and all of them had a standard six wire closure of sternotomy. The patients having any risk factors were placed in group II. The patients in group II were randomized by including every alternate patient from group II to subgroup II A and every other alternate patient from group II to subgroup II B. Patients in subgroup II A again had a standard closure of sternotomy while in patients of subgroup II B bilateral Robiscek repair and four-five interlocking figure of eight wires were used for closure of sternotomy. Results: The patients who had risk factors for sternal dehiscence had higher risk for sternal dehiscence as compared to patients without any risk factors if bilateral Internal Mammary Arteries were harvested for OPCAB. But if we used bilateral Robiscek repair with four to five interlocking figure of eight wires for sternal closure then the rate of sternal complications in the patients with risk factors for sternal dehiscence was not more than the patients without risk factors. Conclusion: We can harvest bilateral Internal Mammary Arteries for OPCAB without fear of sternal complications even in patients with high risk for sternal dehiscence if we use bilateral Robiscek repair with four to five interlocking figure of eight wires for sternal closure.

Comparison of Sternal Wound Complication after Off-Pump CABG between Skeletonized and Pedicled LIMA Harvesting: A Single Centre Experience in Bangladesh

Background: Off-pump coronary artery bypass grafting (OPCAB) is a surgical procedure that has gained popularity due to its potential benefits over traditional coronary artery bypass grafting, including reduced morbidity and mortality. However, sternal wound complication (SWC) remains challenging following the procedure. The technique of left internal mammary artery (LIMA) harvesting has been shown to impact the incidence of SWC. This study aimed to compare the incidence of SWC between two techniques of LIMA harvesting, i.e., skeletonized and pedicled. Methods: The study was conducted at the Department of Cardiac Surgery, Bangabandhu Sheikh Mujib Medical University, and included 60 patients who underwent OPCAB. The patients were divided into two groups of 30 each based on the technique of LIMA harvesting used, i.e., skeletonized (group A) or pedicled (group B). The postoperative ICU care was given to each patient as per the protocol. The statistical analysis was conducted using the SPSS version 26.0 for Windows software. Results: The results showed that 5 (8.33%) patients developed SWC, with 1 (1.67%) patient in group A and 4 (6.66%) patients in group B. However, the occurrence of SWC was not statistically significant between the two groups (p = 0.35). The mean age, gender distribution, and comorbidities such as hypertension, diabetes, dyslipidemia, and anemia were also not statistically significant between the two groups. The number of smokers was statistically significant between the two groups (p = 0.03), and the occurrence of SWC was found to be higher in smoker patients in group B (p = 0.04). Preoperative and postoperative parameters such as duration of operation, duration of mechanical ventilation, duration of chest drains, duration of the central venous line, and amount of postoperative mediastinal bleeding were also not statistically significant between the two groups. The distribution of wound complications, duration of ICU stays, and hospital stay between the two groups was also not statistically significant. Conclusion: In conclusion, this study found that the incidence of SWC was less in skeletonized LIMA harvesting than in pedicled LIMA harvesting after OPCAB. However, this finding was not statistically significant. Further studies with larger sample sizes may be needed to confirm these results and determine the appropriate technique of LIMA harvesting to decrease the incidence of SWC after OPCAB.

Total Arterial Off-Pump Coronary Artery Bypass Grafting： A 1O-Year Experience

Background： Arterial grafts had better mid-term and long-term patency than saphenous vein grafts in coronary artery bypass grafting （CABG）. We summarized our experience with total arterial off-pump coronary artery bypass grafting （OPCAB） and assessed the early clinical results, surgical complications, and follow-up. Methods： From January 2007 to May 2017,508 coronary artery disease patients undergoing total arterial OPCAB were enrolled. Clinical features, approaches, outcomes of surgical treatments, and follow-up data of these patients were studied retrospectively. A total of 122 patients underwent single left internal mammary artery （IMA）-left anterior descending artery grafts, whereas the other 386 patients underwent multiple vessel grafts. Results： The average distal anastomosis was 2.34 ± 0.97 （range： 1-4）. All the patients were discharged from hospital except one died. A total of 457 （90.32%） patients were followed up. In the 4-, 7-, and 10-year follow-up groups, the rate of death from any cause was 1.19%, 6.47%, and 10.67%; rate of cardiac death was 0.60%, 2.88%, and 3.33%; rate of repeat revascularization was 0.00%, 3.60%. and 8.67%; rate ofischemic symptoms was 1.79%, 7.91%, and 11.33%; and incidence of stroke was 2.38%, 4.32%, and 6.67%, respectively. Poor medication adherence was observed in 9.38% of the follow-up population. Conclusions： Total arterial OPCAB with bilateral IMA, radial artery, and right gastroepiploic artery grafting yielded satisfactory early and midterm outcomes in this patient group, without a significant increase in early mortality or morbidity. Moreover, the long-term outcomes are also positive.