Coronary Artery Bypass Grafting Using a Bifurcated Internal Thoracic Artery

Coronary artery bypass grafting was performed successfully on a patient by anastomosing the left internal thoracic artery and its pericardiacophrenic branch to the obtuse marginal and the posterior descending coronary artery, respectively, to form a Y graft. Preoperative angiography of the internal thoracic artery had revealed the presence of an unusually large pericardiacophrenic branch almost the size of the main trunk, which allowed us to plan for bifurcated artery grafting.

Prospective validation of a predictive scoring system for deep sternal wound infection after routine bilateral internal thoracic artery grafting

OBJECTIVES

The Gatti score is a weighted scoring system based on risk factors for deep sternal wound infection (DSWI) that has been specifically created to predict DSWI risk after routine bilateral internal thoracic artery (BITA) grafting. It has not undergone an external validation. The aim of the present study was to perform this validation.

METHODS

BITA grafts were used as skeletonized conduits in 304 (90.7%) of 335 consecutive patients with multivessel coronary artery disease who underwent isolated coronary bypass surgery at the authors' institution between January 2014 and July 2015. Baseline characteristics, operative data and immediate outcomes of every patient were prospectively collected in a computerized data registry. A score was assigned to each patient preoperatively. The goodness-of-fit and the discrimination power of both models, preoperative and combined, of the Gatti score were assessed with the Hosmer-Lemeshow test and the calculation of the area under the receiver-operating characteristic curve, respectively.

RESULTS

Eighteen (5.9%) patients suffered from DSWI. Major differences were found between the original series whence the Gatti score has been derived and the present prospective series. The Gatti score goodness-of-fit was satisfactory for both the preoperative (P = 0.61) and the combined model (P = 0.81). The area under the receiver-operating characteristic curve was 0.82 (95% confidence interval: 0.72-0.91) for the preoperative model and 0.8 (95% confidence interval: 0.71-0.9) for the combined model.

CONCLUSIONS

On the basis of the results of the present prospective study, the Gatti score has proved to be effective in predicting DSWI following BITA grafting despite some differences between the original and the present series of patients. More studies have to be performed in order to strengthen the evidence of this first external validation.

Efficacy of multiple arterial coronary bypass grafting in patients with diabetes mellitus

OBJECTIVES

Use of the left internal mammary artery in patients with diabetes mellitus and multivessel coronary artery disease is known to improve survival after coronary artery bypass grafting (CABG); however, the survival benefit of multiple arterial grafts (MAGs) in diabetic patients is debated. We investigated the efficacy of CABG performed with MAGs in diabetic patients.

METHODS

The overall patient group comprised 2618 consecutive patients who underwent isolated CABG at our hospital between 1990 and 2014. Perioperative characteristics, in-hospital outcomes and long-term outcomes were compared between diabetic (n = 1110) and non-diabetic patients (n = 1508). The long-term outcomes of diabetic and non-diabetic patients were analysed between those who received a single arterial graft (SAG) and those who received MAGs. Both full unmatched patient population and propensity-matched patient population analyses (diabetic cohort = 431 pairs, non-diabetic cohort = 577 pairs) were performed.

RESULTS

Preoperative comorbidities were much more common in the diabetic patients than in the non-diabetic patients; however, comorbidities were not associated with in-hospital outcomes (diabetes versus non-diabetes group, in-hospital mortality: 2.2 vs 1.5%; deep sternal wound infection: 2.2 vs 1.8%, P > 0.05). Although survival and freedom from major cardiac and cerebrovascular events (MACCEs) at 15 years were lower in the diabetes group than in the non-diabetes group (survival: 48.6 vs 55.0%, P = 0.019; MACCE-free survival: 40.8 vs 46.1%, P = 0.02), cardiac death-free survival at 15 years was similar (81.7 vs 83.9%, P = 0.24). Overall, 12-year survival was higher in both diabetic and non-diabetic patients treated with MAGs than in those treated with an SAG (64.9 vs 56.8%, P = 0.006, and 71.9 vs 60.5%, P < 0.001). Propensity-matched patient cohort analysis revealed improved 12-year survival with MAGs versus SAG in both the diabetes group (64.9 vs 58.8%, P = 0.041) and non-diabetes group (71.4 vs 63.8%, P = 0.014). Similarly, MACCE-free survival was improved in both groups.

CONCLUSIONS

A long-term survival advantage, with no increase in perioperative morbidity, is conferred with the use of multiple arterial bypass grafts not only in non-diabetic patients but also in diabetic patients.

Myocardial Revascularization Exclusively With Bilateral Internal Thoracic Arteries in T-Graft Configuration: Effects on Late Survival

BACKGROUND

We studied long-term survival using bilateral internal thoracic artery (BITA) grafting in a T-configuration exclusively versus using single internal thoracic artery (SITA) grafting in patients with multivessel disease.

METHODS

Consecutive coronary operations performed at a single center between 1996 and 2014 were reviewed. Long-term survival among patients receiving coronary revascularization exclusively with BITA grafting in a T-configuration (n = 2,098) versus SITA grafts plus other types of conduits (saphenous vein graft [SVG] and radial artery [RA]) grafts (n = 1,659). In patients who underwent BITA grafting, the left internal thoracic artery (LITA) was grafted mainly to the left anterior descending artery, whereas the right internal thoracic artery (RITA) was used more commonly to graft the circumflex (Cx) artery and the right coronary system as T-grafts. A total of 485 pairs of patients were matched using propensity scores. Cox proportional hazard models were generated to examine the association of arterial BITA grafting with mortality.

RESULTS

Patients in the BITA group were more likely to be younger (BITA, 63.7 ± 9.1 versus SITA, 65.0 ± 9.9; p < 0.0001). At 30 days, patients who underwent BITA grafting experienced reduced unadjusted mortality (BITA, 1.2% versus SITA, 4.4%; p < 0.0001). At 10 years, patients who underwent BITA grafting experienced superior unadjusted survival (BITA, 82.6% ± 1.8% versus SITA, 76.1% ± 1.3%; p = 0.001). Cox regression analysis in the entire study cohort showed that BITA grafting was associated with improved survival (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.58-0.87; p < 0.001). In the propensity-score-adjusted analysis, patients who underwent BITA grafting had similar in-hospital mortality (BITA, 1.6% versus SITA, 2.9%; p = 0.196). Patients who underwent BITA grafting still showed improved survival at 10 years (BITA, 81.0% ± 4.1% versus SITA, 71.8% ± 2.5%; p = 0.039).

CONCLUSIONS

This study suggests that coronary artery operations exclusively with BITA grafting in a T-configuration may be associated with better long-term survival than grafting with SITA plus other types of conduits.

Minimally Invasive Coronary Artery Bypass Grating Using Bilateral In Situ Internal Thoracic Arteries

When performing minimally invasive coronary artery bypass grafting (MICS CABG), it is difficult to access the right internal thoracic artery (ITA) under direct vision. We successfully performed off-pump MICS CABG using the bilateral in situ ITAs through a 8-cm left thoracotomy under direct vision for a 76-year-old man. His postoperative course was uneventful and all the grafts were patent. This novel, minimally invasive approach safely preserves the sternum and delivers the benefits of bilateral in situ ITA grafting, providing an alternative to conventional CABG and off-pump CABG.

Total arterial anaortic off-pump coronary artery bypass grafting for diffuse coronary disease - A case report

Surgical treatment of diffuse coronary artery disease remains challenging. We present here a diabetic patient, with diffuse coronary disease, revascularized using total arterial anaortic off-pump coronary artery bypass grafting. He received total nine distal grafts. He continues to be asymptomatic after more than 2 years. CT angiography follow-up shows eight out of nine grafts are patent. Anaortic off-pump coronary artery bypass grafting has the least incidence of stroke and arterial grafts have the best long-term patency rate. This is the first case report of nine arterial bypass graft performed off-pump using both internal mammary and both radial arteries. Anaortic total arterial off-pump coronary artery bypass grafting has achieved excellent intermediate term result in this patient of diffuse coronary artery disease.

[Policy of using the right internal thoracic artery "in situ" for coronary artery bypass grafting]

The authors analysed the outcomes in a total of 73 patients subjected to coronary artery bypass grafting with the use of the "in situ" the right internal thoracic artery. Of these, 14 patients endured bypass grafting with assessment of the conformity of the length of the "in situ" right ITA as a conduit for the distal third of the right coronary artery (RCA). 16 patients underwent grafting of the RITA "in situ" with the RCA by passing through the pleural cavity. The remaining 43 patients were subjected to bilateral mammary composite bypass grafting using the radial artery (RA). A total of 22 segments of the RA were subjected to a comparative morphometric examination depending on the method of exposure. We additionally analysed 56 cases of utilizing the RA with the use of the pharmacological protocol of preventing spasm. The results were regarded statistically significant if p<0.05. We used the non-parametric criterion of Mann-Whitney. The obtained results showed that the right ITA "in situ" may be used for bypass grafting of the RCA system, excluding the risk of graft tension, if the perpendicular from the 6th intercostal space crosses the sharp edge of the heart 1.5-2 cm distal to the medial point, with the minimum number of complications after 1.5±0.3 years (7.1%). When the above-mentioned perpendicular is located proximal to the middle point of the sharp edge of the heart it is possible to use the right ITA "in situ" for the RCA system thanks to passing the conduit through the right pleural cavity under the anterior segment of the upper lobe and the medial segment of the middle lobe of the right lung with no complications after 1 year. The method of composite bypass grafting by means of the proximal segment of the right ITA "in situ" and the RA makes it possible to effectively revascularize any portions of the coronary bed (latency 94.7% after 3.0±0.8 years), to avoid manipulations on the aorta, and to save the bed of the right ITA in the middle and distal third of the sternum with no postoperative complications. It was revealed that in the conditions of decreased osmotic pressure the increase in the thickness of the vascular wall is more pronounced in the skeletonized segments of the RA (1.38±0.05 mm) as compared with the segments surrounded by connective and fatty tissue (1.09±0.04 mm). The pharmacological protocol for prevention of radial artery spasm used in 56 patients resulted in a small number of complications observed after 3.0±0.8 years (myocardial infarctions - 1.75%, angina pectoris relapse - 7%). Hence, the developed methods of using the right ITA "in situ" widen possibilities of bilateral mammary bypass grafting, excluding the existing problems of routine use of the both ITAs "in situ".

Internal mammary artery graft dissection: a case-based retrospective study and brief review

The left internal mammary artery is the preferred graft for treating left anterior descending coronary artery disease. Dissection is a rare but grave sequela of internal mammary artery graft angiography. The available medical literature is scant, perhaps as a result of under-reporting. We report a case in which dissection of the internal mammary artery graft occurred during diagnostic angiography, and we discuss its management. In addition, we review the available literature and provide a retrospective analysis of the data from our own catheterization laboratory. In our single-center analysis of 542 cases of selective internal mammary artery graft angiography, we found only the single case of internal mammary artery graft dissection (0.2%) that we report here. Our review of the literature revealed 7 reported cases of internal mammary artery graft dissection, 3 of which were iatrogenic. There were no identifiable risk factors for such dissection. After treatment with angioplasty and stenting, all patients had good outcomes during follow-up.

Aortocoronary bypass graft patency assessed by coronary computed tomography angiography--unicentric study

Coronary artery bypass graft (CABG) surgery is used to revascularize ischemic myocaydium affected by coronary artery obstruction. Conventional coronary angiography (CCA) is an invasive method used for graft evaluation. Nowadays, in post CABG patients grafts can be assessed noninvasively by using coronary computed tomography angiography (CCTA).

AIM

To determine the late patency rate in coronary bypass grafts using CCTA.

METHODS

To assess graft patency, sixty post CABG patients (51/60 males and 9/60 females) were evaluated using dual source computed tomography (DSCT) angiography. All patients underwent a primary isolated CABG surgery between January 2000 and December 2004, performed by a single surgeon, at the Dartment of Cardiovascular Surgery, "Prof. Dr. George I. M. Georgescu" Institute for Cardiovascular Diseases, Iaşi, Romania. The grafts were classified as patent, occluded and stenotic (stenosis >50%).

RESULTS

The mean age of patients was 68.05-7.59 years and the mean time after graft implantation was 129.53-16.74 months. The number of assessed grafts was 200, including 146 saphenous vein grafts (SVG) and 54 in situ left internal mammary artery (LIMA) grafts. A total number of 105/146 (71.92%) venous grafts and 52/54 (96.3%) arterial grafts were patent.

CONCLUSION

Nowadays, computed tomography angiography is a modern noninvasive imaging modality used to evaluate the aortocoronary graft patency in early and late postoperative settings. In our study, the late saphenous graft patency rate was superior to that found in earlier angiographic studies.

The descending branch of the lateral femoral circumflex artery is a good option in CABG with arterial grafts

INTRODUCTION

The descending branch of the lateral femoral circumflex artery is an option for coronary artery bypass grafting.

OBJECTIVE

To evaluate the early patency and adaptation of lumen diameter using multidetector computed angiotomography.

METHODS

Thirty-two patients were selected to undergo coronary artery bypass grafting using the descending branch of the lateral circumflex artery, the internal thoracic artery, and other grafts. Evaluations were carried out through high resolution computed tomography performed on the 7th and 90th postoperative day. Diameters of the descending branch of the lateral circumflex artery and the left internal thoracic artery were measured 3 cm before the distal anastomosis, in the middle portion, and 3 cm after the proximal anastomosis. Diameters were compared using paired t-test (P<0.05).

RESULTS

Descending branch of the lateral femoral circumflex artery wDescending branch of the lateral femoral circumflex artery was used in 26 patients, as its use was not viable in six patients (18%). It was used as composite graft in all cases. The anterior descending branch was revascularized by the left internal thoracic artery in all cases. Patency rates of the descending branch of the lateral femoral circumflex artery were 96% and 92%, respectively. No occlusions were observed in the left internal thoracic artery (LITA) and no ischemic events were observed in the descending branch of the lateral circumflex. Descending branch of the lateral femoral circumflex artery increased the lumen diameter in the middle (P=0.001) and distal portions (P=0.006); the left internal thoracic artery (LITA) increased in the middle portion (P=0.001).

CONCLUSION

Similar to the left internal thoracic artery, the descending branch of the lateral femoral circumflex artery showed high patency rate and positive luminal adaptation. This early evaluation confirms the descending branch of the lateral femoral circumflex artery as a potential alternative for grafting. Due to anatomical variations, preoperative femoral angiographic evaluation appears to be mandatory.

Initial experience with internal mammary artery harvesting with the da Vinci Surgical System for minimally invasive direct coronary artery bypass

PURPOSE

We evaluated the feasibility of off-pump minimally invasive direct coronary artery bypass (MIDCAB) in combination with robotic harvesting of the left internal mammary artery (LIMA).

METHODS

Since 2004, 33 patients [average age, 64 years; 27 males (82%)] have undergone MIDCAB with robotic LIMA harvesting performed through the fourth or fifth intercostal space with guidance by enhanced computed tomography (CT).

RESULTS

No deaths or major adverse cardiac events occurred. Robotic LIMA harvesting was completed in 30 cases (91%), while three cases (9%) required conversion to a median sternotomy due to bleeding. The risk of LIMA injury significantly increased with age (p = 0.0012). For the 30 successful cases, the average harvest time was 68 min, and the average intraoperative blood loss was 306 ml, with only three patients (9%) requiring a transfusion. The graft flow was measurable in all cases (average, 34 ml/minute). All grafts were shown to be patent in postoperative evaluations, although CT revealed that the LIMA in one patient was anastomosed to an untargeted artery.

CONCLUSIONS

Off-pump MIDCAB in combination with robotic harvesting of the LIMA is a reasonable and less invasive procedure than the standard procedures. Potential problems include difficulty controlling bleeding from the graft, especially in elderly patients, and proper identification of the target artery.

Outcomes of off-pump coronary bypass grafting with the bilateral internal thoracic artery for left ventricular dysfunction

This study evaluated the outcomes of off-pump coronary artery bypass surgery (OPCAB) with severe left ventricular dysfunction using composite bilateral internal thoracic artery grafting. From January 2001 to December 2008, 1,842 patients underwent primary isolated OPCAB with composite bilateral internal thoracic artery grafting. A total of 131 of these patients were diagnosed with a severely depressed preoperative left ventricle ejection fraction (LVEF) (≤ 0.35). These patient outcomes were compared with the outcomes of 830 patients that had mildly or moderately depressed LVEF (0.36 to 0.59) and 881 patients with normal LVEF (>0.6). The early mortality for patients with severe LVEF was 2.3%. The 3-yr and 7-yr survival rate for patients with severe LV dysfunction was 86.0% and 82.8%, respectively. Multivariate analysis showed that severe LV dysfunction EF increased the risk of all-cause death (P=0.012; hazard ratio [HR],2.14; 95% confidence interval [CI],1.19-3.88) and the risk of cardiac-related death (P=0.008; HR,3.38; 95% CI, 1.37-8.341). The study identified positive surgical outcomes of OPCAB, although severe LVEF was associated with two-fold increase in mortality risk compared with patients who had normal LVEF.

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.

Bilateral internal thoracic artery harvest and deep sternal wound infection in diabetic patients

BACKGROUND

Coronary artery bypass graft surgery is superior to percutaneous intervention in diabetic patients with multivessel disease. The use of bilateral internal thoracic arteries (BITA) may provide better long-term graft patency, but the risk of postoperative deep sternal wound infection has limited its use in diabetic patients. However, studies have reported conflicting results, and require systematic evaluation.

METHODS

MEDLINE, EMBASE, World of Science, and the Cochrane library were searched for randomized controlled trials and observational studies comparing the incidence of deep sternal wound infection in diabetic patients undergoing either left internal thoracic artery (LITA) or BITA harvest. We used random effect models to compare risk ratios within groups.

RESULTS

One randomized controlled trial and 10 observational studies (126,235 diabetic patients: 122,465 LITA, 3,770 BITA) met inclusion criteria. Deep sternal wound infection occurred in 3.1% and 1.6% for the BITA and LITA cohorts, respectively. The risk ratio for deep sternal wound infection development was 1.71 (1.37 to 2.14) for BITA compared with LITA. Patients who underwent skeletonized BITA harvest had a similar risk of deep sternal wound infection compared with LITA (0.9 [0.42 to 2.09]), although pedicled harvest demonstrated increased risk (1.77 [1.4 to 2.23]). Early mortality was comparable in the LITA cohort (2.5%) and the BITA cohort (2.3%; p = 0.8).

CONCLUSIONS

The risk of deep sternal wound infection can be minimized in diabetic patients undergoing coronary artery bypass graft surgery by performing ITA harvested in a skeletonized manner with meticulous attention to preserving sternal blood flow. Pedicled harvest is to be discouraged when utilizing both ITA owing to a significant increase in the risk of postoperative deep sternal wound infection.

Transthoracic Doppler echocardiography of the left internal mammary artery graft

Assessment of the left internal mammary artery (LIMA) graft patency currently requires invasive investigation through coronary angiography. In the last years the successful application of noninvasive Doppler spectrum analysis has been reported for patency assessment of the LIMA graft after myocardial revascularization. Echocardiography is considered to be a sensitive noninvasive screening modality to diagnose critical narrowing of LIMA grafts and angiography should be reserved for cases in which Doppler echocardiography fails to visualize the LIMA or reveals an abnormal flow pattern.

[Intraoperative assessment of composite bypass grafts by means of ultrasonic Doppler flowmetry]

The use of the both internal thoracic arteries while forming a composite bypass graft has been suggested as a method making it possible to carry out total myocardial revascularization. However, controversial still remain the problem of the distribution of blood in these bypass grafts, as well as that concerning T-grafts' capability of providing the sufficient blood inflow to the basin of the coronary arteries being bypassed. The method of ultrasonic Doppler flowmetry was used to perform the intraoperative assessment of 59 composite bypass grafts along such parameters as the pulsatility index (PI), mean volume blood flow velocity (Qmean), and percentage of diastolic volumetric filling (DF). The obtained findings were statistically processed making it possible to obtain the average parameters of blood flow for the composite bypass grafts and their branches. A dependence was established between blood flow distribution in the composite conduit and the degree of the lesion of the artery being bypassed.

In vitro effects of lidocaine hydrochloride on coronary artery bypass grafts

AIM

Coronary artery bypass grafting (CABG) is one of the most common procedures performed to improve blood supply to myocardium. The characteristics of grafts, mechanical stress and pharmacological agents have substantial influence on the short and long term graft patency. Lidocaine is among the most frequently used antiarrhythmic agents perioperatively. The aim of this study was to evaluate the in vitro effects of lidocaine on internal mammarian artery (IMA), radial artery (RA) and saphenous vein (SV) grafts.

METHODS

Using standard tissue bath techniques, responses to increasing concentrations of lidocaine hydrochloride were obtained, in segments of IMA, RA and SV grafts. Twenty patients were enrolled in the study with a total number of 48 grafts (16 for IMA, RA and SV grafts each). In vitro lidocaine concentrations between 10(-9)M and 10(-3.5)M were studied to represent therapeutic plasma concentration of 1.5-5 mcg/mL.

RESULTS

In IMA and RA grafts, lidocaine hydrochloride caused vasodilatation (40.5±1.9% and 39.1±2.6 % respectively) at concentrations between 10(-9) to 10(-7.5) M while causing a dose dependent vasoconstriction response at concentrations above 10(-7.5) M. In SV graft samples, lidocain hydrochloride caused vasodilatation (24.4±1.9 %) at concentrations between 10(-9) to 10(-7) M while causing dose dependent vasoconstriction at concentrations above 10(-7) M. For vasoconstriction effect, mean±SD values for E(max) were calculated as: 120.1±6.6% in IMA, 83.35±5.06% in RA, and 154.0±13.8% in SV. The vasoconstriction in the SV samples was higher than in the RA and IMA. The mean ±SD LogEC(50) values were -5.15±0.27, -5.76±0.11 and -5.56±0.19 for SV, IMA and RA grafts respectively.) There was a statiscally significant differences in the Log EC(50) values between SV, IMA and RA (P<0.005)

CONCLUSION

Based on the results of our study, we conclude that, increasing doses of lidocaine in the perioperative period may cause vasospasm in IMA, RA and SV grafts. Thus, avoiding high doses may have a role in improving perioperative and long term mortality.