Resilience of the Internal Mammary Artery to Atherogenesis: Shifting From Risk to Resistance to Address Unmet Needs.

Fueled by the global surge in aging, atherosclerotic cardiovascular disease reached pandemic dimensions putting affected individuals at enhanced risk of myocardial infarction, stroke, and premature death. Atherosclerosis is a systemic disease driven by a wide spectrum of factors, including cholesterol, pressure, and disturbed flow. Although all arterial beds encounter a similar atherogenic milieu, the development of atheromatous lesions occurs discontinuously across the vascular system. Indeed, the internal mammary artery possesses unique biological properties that confer protection to intimal growth and atherosclerotic plaque formation, thus making it a conduit of choice for coronary artery bypass grafting. Its endothelium abundantly expresses nitric oxide synthase and shows accentuated nitric oxide release, while its vascular smooth muscle cells exhibit reduced tissue factor expression, high tPA (tissue-type plasminogen activator) production and blunted migration and proliferation, which may collectively mitigate intimal thickening and ultimately the evolution of atheromatous plaques. We aim here to provide insights into the anatomy, physiology, cellular, and molecular aspects of the internal mammary artery thereby elucidating its remarkable resistance to atherogenesis. We propose a change in perspective from risk to resilience to decipher mechanisms of atheroresistance and eventually identification of novel therapeutic targets presently not addressed by currently available remedies.

A New Current to The Armamentarium: Is the CHA2DS2-Vasc-HS Score Predictive of Low Left Internal Mammary Artery (LIMA) Flow in Patients Underwent Coronary Bypass Surgery?

INTRODUCTION: Left internal mammary artery (LIMA) grafts should be used in patients undergoing CABG. No other procedure results in patency equivalent to that of the left anterior descending coronary artery (LAD)-LIMA bypass graft. The CHA2DS2-Vasc-HS scoring system can be used to successfully predict CAD severity in stable CAD patients. We aimed to investigate the relationship between LIMA flow and the CHA2DS2-Vasc-HS score. METHODS: A total of 684 patients, who underwent CABG surgery, were included in this study. Previous history of bypass surgery, emergency operations, patients with Leriche syndrome and patients with severe obstructive pulmonary and subclavian artery disease were excluded from our study. Patients with a LIMA flow that was suitable for bypass grafting, as determined during the intraoperative evaluation, were included in the low LIMA flow group, and the CHA2DS2-Vasc-HS score was calculated for all patients. RESULTS: Patients in the low LIMA flow group (Group 1) were older. The CHA2DS2-Vasc-HS score (P < 0.001), presence of mild or moderate COPD (P = 0.022), number of severely diseased vessels (P = 0.036), and BMI (P < 0.001) were independent predictors of poor LIMA flow. The cutoff value of the CHA2DS2-VASc-HS score for the prediction of poor LIMA flow was >5.5, with a sensitivity of 92.9% and specificity of 83.4% (AUC: 0.938, 95% Cl: 0.906 - 0.970, P < 0.001). CONCLUSION: A preoperative high CHA2DS2-Vasc-HS score can be used to predict low intraoperative LIMA flow. The CHA2DS2-Vasc-HS score is an easy-to-use and reliable estimation method and can be used as an additional preoperative of LIMA flow in patients undergoing CABG due to severe CAD.

Patency of conduits in patients who received internal mammary artery, radial artery and saphenous vein grafts.

BACKGROUND: Where each patient has all three conduits of internal mammary artery (IMA), saphenous vein graft (SVG) and radial artery (RA), most confounders affecting comparison between conduits can be mitigated. Additionally, since SVG progressively fails over time, restricting patient angiography to the late period only can mitigate against early SVG patency that may have occluded in the late period. METHODS: Research protocol driven conventional angiography was performed for patients with at least one of each conduit of IMA, RA and SVG and a minimum of 7 years postoperative. The primary analysis was perfect patency and secondary analysis was overall patency including angiographic evidence of conduit lumen irregularity from conduit atheroma. Multivariable generalized linear mixed model (GLMM) was used. Patency excluded occluded or "string sign" conduits. Perfect patency was present in patent grafts if there was no lumen irregularity. RESULTS: Fifty patients underwent coronary angiography at overall duration postoperative 13.1 ± 2.9, and age 74.3 ± 7.0 years. Of 196 anastomoses, IMA 62, RA 77 and SVG 57. Most IMA were to the left anterior descending territory and most RA and SVG were to the circumflex and right coronary territories. Perfect patency RA 92.2% was not different to IMA 96.8%, P = 0.309; and both were significantly better than SVG 17.5%, P < 0.001. Patency RA 93.5% was also not different to IMA 96.8%, P = 0.169, and both arterial conduits were significantly higher than SVG 82.5%, P = 0.029. Grafting according to coronary territory was not significant for perfect patency, P = 0.997 and patency P = 0.289. Coronary stenosis predicted perfect patency for RA only, P = 0.030 and for patency, RA, P = 0.007, and SVG, P = 0.032. When both arterial conduits were combined, perfect patency, P < 0.001, and patency, P = 0.017, were superior to SVG. CONCLUSIONS: All but one patent internal mammary artery or radial artery grafts had perfect patency and had superior perfect patency and overall patency compared to saphenous vein grafts.

Can the Wall Shear Stress Values of Left Internal Mammary Artery Grafts during the Perioperative Period Reflect the One-Year Patency?

PURPOSE: The left internal mammary artery (LIMA) is the preferred graft for coronary artery bypass grafting, but the reasoning for LIMA occlusion is unclear. We sought to examine whether the wall shear stress (WSS) values of LIMA grafts during the perioperative period reflected the 1-year patency by using combining computational fluid dynamics (CFD) and coronary computed tomography angiography (CCTA) images. METHODS: CCTA was performed in 233 patients with LIMA graft perioperatively and 1 year later from October 2014 to May 2017. LIMA occlusion was detected in six patients at the 1-year follow-up CCTA. Two patients were excluded due to poor imaging quality. The remaining four patients were enrolled as occlusive (OCC) group, and eight patients with patent LIMA were recruited as patent (PAT) group. The WSS values of LIMA during perioperative period were calculated. LIMA graft was artificially divided into three even segments, proximal (pLIMA), middle (mLIMA) and distal (dLIMA) segments. The independent samples t-test and the Student-Newman-Keuls test were used. RESULTS: The WSS values of dLIMA were significantly higher in the PAT group than in the OCC group (4.43 vs. 2.56, p < 0.05). The WSS values of dLIMA in the PAT group were significantly higher than pLIMA, which was absent in the OCC group. CONCLUSIONS: A higher WSS value of the distal segment of LIMA and a higher WSS value of the distal segment compared with the proximal segment of LIMA in the PAT were observed; this tendency might be helpful in predicting the 1-year patency of LIMA.

Patency When Grafted to Coronary Stenosis More Than 50% in LIMA-RA-Y Grafts.

BACKGROUND: Recent coronary surgery practice is to graft arterial conduits to more severely stenosed coronary targets than in the past. We aimed to investigate postoperative arterial graft patency with native coronary stenosis at the time of surgery, using the left internal mammary artery and radial artery (RA) as a composite Y graft (LIMA-RA-Y). In the study timeframe, it was routine clinical practice to graft coronary arteries with >50% stenosis. METHODS: Of 464 patients previously reported 1996-1999, 346 who underwent LIMA-RA-Y at the Royal Melbourne Hospital, 76 had postoperative angiograms at the same institution. Each anastomosis was considered separately. For arterial grafts a "string sign" was analysed as being occluded. Predictor of patency was performed with a generalised linear mixed model (GLMM). RESULTS: Seventy-six (76) patients had postoperative angiograms at 5.8±5.4 years (range 0.23-19.4; interquartile range 1.7-10.0) years postoperative; with age at operation 62.5±10.7 years and 3.4±0.8 grafts per patient, 82% were male. Of 256 anastomoses, 230 were to coronary targets >50% stenosis. Overall patency was 84.0% (214/256). For coronary stenosis >50%, patency was 88% (201/230) and varied by coronary territory left anterior descending (LAD) 94% (87/93), circumflex 90% (71/79) and right coronary artery (RCA) 74% (43/58). Interaction for coronary territory was significant (p=0.022). Higher preoperative coronary stenosis predicted higher patency; with odds ratio for improved patency of 1.83 (95% CI 1.51, 2.22), p<0.001 for each 10% increase in stenosis. CONCLUSIONS: Late patency of composite arterial grafts is acceptable when grafted to coronary arteries of greater than 50% stenosis.

Endothelial nitric oxide synthase enhancer AVE3085 reverses endothelial dysfunction induced by homocysteine in human internal mammary arteries.

Homocysteine (Hcy) is an independent risk factor for endothelial dysfunction in cardiovascular diseases. We hypothesized that the eNOS transcription enhancer AVE3085 may protect the endothelial function damaged by Hcy in the human internal mammary artery (IMA). Cumulative concentration-relaxation curves to acetylcholine (-10 to -4.5 log mol/L) or sodium nitroprusside were established in IMA from patients undergoing coronary artery surgery precontracted by U46619 (-8 log mol/L) in the absence/presence of Hcy (100 µmol/L) with/without AVE3085 (30 µmol/L) in vitro in a myograph. RT-qPCR and ELISA were used to quantify the mRNA and protein levels of eNOS. Colorimetric assay method was used to detect the production of nitric oxide (NO). Maximal relaxation was significantly attenuated by Hcy in human IMA. Co-incubation with AVE3085 protected endothelium from the impairment by Hcy and increased the production of NO. Exposure to Hcy for 24 h downregulated eNOS protein expression (P < 0.05) whereas it upregulated the expression of eNOS at mRNA levels (P < 0.05). The presence of AVE3085 in addition to Hcy significantly increased the eNOS protein (P < 0.05) and slightly decreased the mRNA level. The study for the first time revealed that in the human blood vessels (IMA) the clinically-relevant high concentration of Hcy directly causes endothelial dysfunction by downregulating eNOS protein that may be reversed by AVE3085. These findings not only provide new direction for protecting endothelium during coronary artery bypass grafting and improving long-term patency of the grafts, but also provide evidence to the use of eNOS enhancer in the patients with endothelial dysfunction in various pathological conditions.

Responsiveness of internal thoracic arteries to nitroglycerin in patients with renal failure.

Nitroglycerin is commonly used as an antispasmodic for treating spasm of coronary artery bypass grafts. This study investigated whether the presence of renal failure affects reactivity to nitroglycerin in internal thoracic arteries obtained from patients undergoing coronary bypass surgery. The patients were divided into three groups according to estimated glomerular filtration rate (eGFR, mL/min/1.73 m2): without renal failure (60 ≤ eGFR, n = 13), with moderate renal failure (30 ≤ eGFR < 60, n = 10), and with severe renal failure (eGFR < 30, n = 10). Organ chamber technique was used to evaluate concentration-related responses of isolated internal thoracic arteries to vasodilators. Nitroglycerin induced a concentration-dependent relaxation, which was significantly augmented in patients with severe but not moderate renal failure than in those without renal failure. In addition, there was a negative correlation between eGFR and the relaxant efficacy of nitroglycerin (P = 0.016). On the other hand, relaxant responses to BAY 60-2770 (which enhances cGMP generation as with nitroglycerin) were similar among three grades of renal function. An inverse relationship of eGFR to the relaxant efficacy of BAY 60-2770 was not observed, either (P = 0.314). These findings suggest that severe renal failure specifically potentiates nitroglycerin-induced relaxation in internal thoracic artery grafts.

A Study Demonstrating the Quantitative Relationship Between Internal Thoracic Artery Length and Free Flow.

BACKGROUND: The left internal thoracic artery (LITA) is the most commonly used arterial bypass conduit in coronary artery bypass graft (CABG) patients and inadequate LITA flow can result in an increase in morbidity and mortality. In this study, we evaluated the effect of excision of the distal spasmodic segment of the LITA on the free flow in CABG patients. METHODS: This study consisted of 47 patients who underwent elective CABG performed with or without other cardiac surgery, between July 2015 and December 2015. Excised LITA length was shorter than 15mm in group 1, between 15mm and 30mm in group 2 and longer than 30mm in group 3. Left ITA free flow was measured for 60seconds into a container before and after the distal LITA excision. The inter-measurement differences were calculated for the three groups. Thereafter, the comparison was performed in terms of free flow difference amongst the three groups. RESULTS: The mean difference of LITA free flow was 27.6±22.7ml/minute in group 1, 35.4±26.7ml/minute in group 2, and 52.6±26.1ml/minute in group 3. There were significant differences in terms of free flow difference between the groups (p=0.008). Also, differences were statistically significant in group 1 versus group 3 (p=0.003) and group 2 versus group 3 (p=0.038) in the intergroup comparisons. CONCLUSIONS: The distal part of the LITA has more spasmodic potential than other segments. This spasm may result in low flow of LITA grafts. Therefore, an as long as possible excision of the distal LITA segment may be required to avoid the spasmodic effect.

In Situ Skeletonized Right Internal Mammary Artery Bypass Grafting to Left Anterior Descending Artery.

This study aimed to evaluate the feasibility and the mid-term efficacy of an in situ skeletonized right internal mammary artery (IMA) bypass grafting to a left anterior descending artery (LAD), and to determine risk factors for IMA graft failure in a single-center study.From January 2012 to December 2015, 189 patients (173 males, 50.6 ± 6.0 years old) undergoing first isolated coronary artery bypass grafting surgery with the in situ skeletonized right IMA grafting to the LAD were included in this study. Baseline characteristics, peroperative data, and follow-up outcomes were investigated and analyzed.The length of the in situ skeletonized right IMA grafts was 18.6 ± 1.2 cm (17.0-22.0 cm). Intraoperative graft flow of the in situ skeletonized right IMA grafting to LAD was 42 ± 9 mL/minute (18-72 mL/minute) associated with measured pulsatility index of 0.8-4.3. In-hospital mortality was 0.5%. Postoperative morbidity included acute myocardial infarction (0.5%), stroke (0.5%), and deep sternal wound infections (1.1%). The mid-term survival was 97.2% and the incidence of repeat revascularization was 0.6%. The patency rate of the in situ skeletonized right IMA grafting to the LAD was 97.1% by computed tomography angiography examination during the follow-up period of 23.2 ± 9.7 months. Additionally, logistic regression analysis showed that intraoperative graft flow had an independent influence on the risk of the mid-term right IMA graft failure.The strategy of the in situ skeletonized right IMA grafting to the LAD is feasible and effective. Intraoperative graft flow was an independent risk factor for the mid-term right IMA graft failure.

Blood transfusions may impair endothelium-dependent vasodilatation during coronary artery bypass surgery.

OBJECTIVE: The hemolytic product free-hemoglobin (fHb) reduces nitric oxide (NO) bioavailability. The present study aims to establish whether administration of different blood transfusions result in increased circulating fHb levels and NO consumption with effects on arterial NO-dependent blood flow in patients undergoing CABG surgery. METHODS: Ninety-five consecutive patients undergoing elective CABG surgery were prospectively divided in four groups based on blood transfusion requirements during surgery: stored blood cells (SBC, n. 21), intraoperative autologous salvaged blood (ASB, n. 25), SBC and ASB (n.22), no transfusion (control, n. 27). Blood samples were collected before and after intervention to analyse plasma levels of fHb and NO consumption. Endothelium-dependent relaxation was assessed in left internal mammary artery (LIMA) rings harvested before chest closure. Peripheral artery tonometry was assessed after intervention. RESULTS: Transfusions with SBC increased plasma fHb (p<0.05). Transfusions of ASB resulted in higher plasma fHb compared to SBC (p<0.01). fHb concentrations directly correlated with NO consumption (r=0.65, p<0.001). Maximal endothelium-dependent relaxation in LIMA was significantly attenuated in SBC and ASB patients compared to control (15.2±3.1% vs 21.1±2.5% vs 43±5.0% respectively; p<0.01). Significant correlations were identified between the aortic pressure wave velocity, plasma fHb concentration and NO consumption (p<0.01). CONCLUSIONS: Intraoperative blood transfusions and particularly autologous salvaged blood impair endothelium-dependent relaxation through NO scavenging by fHb. These findings obtained in vitro and in vivo provide new insights into the adverse relation between blood transfusions and patient outcome.

On the relationship between competitive flow and FFT analysis of the flow waves in the left internal mammary artery graft in the process of CABG.

BACKGROUND: During coronary artery bypass grafting (CABG), the ratio of powers of the fundamental frequency and its first harmonic (F0/H1) in fast Fourier transformation (FFT) analysis of the graft's flow waves has been used in the field of evaluation of the patency in anastomosis. But there is no report about using the FFT method to evaluate the magnitude of competitive flow. This study is aiming at exploring the relationship between competitive flow and FFT analysis of the flow waves in left internal mammary artery (LIMA) graft, and finding a new method to evaluate the magnitude of competitive flow. METHODS: At first, establishing the CABG multiscale models of different stenosis in left anterior descending artery (LAD) to get different magnitude of competitive flows. Then, calculating the models by ANSYS-CFX and getting the flow waves in LIMA. Finally, analyzing the flow waves by FFT method and comparing the FFT results with the magnitude of competitive flow. RESULTS: There is no relationship between competitive flow and F0/H1. As for F0/H2 and F0/H3, they both increase with the reduction of the stenosis in LAD. But the increase of F0/H3 is not obviously enough and it can't identify the significant competitive flow clearly, so it can't be used as the evaluation index. It is found that F0/H2 increases obviously with the increase of the competitive flow and can identify the significant competitive flow. CONCLUSION: The FFT method can be used in the evaluation of competitive flow and the F0/H2 is the ideal index. High F0/H2 refers to the significant competitive flow. This method can be used during CABG to avoid the risk of competitive flow.

Change of luminal diameter of skeletonized and non-skeletonized radial artery graft at early and late postoperative period.

The radial artery is increasingly used as a second arterial conduit for myocardial revascularization. However, the radial artery is susceptible to vasospasm, which is thought to be the principal cause of graft failure. The radial artery is harvested as a skeletonized or a non-skeletonized graft, but the effect of different harvesting technique remains unknown. In this study, we compared the early- and mid-term angiographic findings to elucidate its influence on the graft luminal diameter. We harvested 39 radial arteries either as a skeletonized (n = 18) or a non-skeletonized graft (n = 21) using an ultrasonic scalpel. We constructed a composite straight graft by combining a right internal thoracic artery and a radial artery. All the radial artery grafts were sequentially anastomosed to coronary arteries. We measured the diameters of the radial arteries before the operation, within 1 month and 1 year after the operation. At early postoperative period, graft diameter was significantly larger in skeletonized grafts. Graft diameter at the point before the first and the second anastomosis was similar in skeletonized grafts, although that was significantly smaller before the second anastomosis in non-skeletonized grafts. However, 1 year after the operation, the graft diameter was comparable and equally reduced after the first anastomosis in both groups. Skeletonization with an ultrasonic scalpel increases the luminal diameter of the radial artery graft at early postoperative period, which, however, reduces possibly as adaptation to graft flow 1 year after the operation.

Potassium induced contraction of the internal thoracic artery in vitro is time related: the potential consequences in the analysis of the mechanism of the spasm after coronary artery bypass grafting and in the analysis of the results of in vitro studies.

The aim of the present study was to examine how, under in vitro conditions, the human left internal thoracic artery (LITA) reacts to contractile agonist:potassium chloride (KCL) as a function of time, as well as to examine whether a change in the LITA reactivity can correlate with the occurrence of the refractory vascular spasm (RVS). Distal segments of LITA obtained from 33 patients aged 38-73, at the time of routine coronary artery surgical revascularization (CABG). Contractile response to 80 mmol K(+) was recorded under isometric conditions. In 16 (48,5 %) LITA segments, contractile reaction to K(+) after experiments ranging 1-10 h were registered. No contractile response even after 10 h of incubation was observed in 17 (51.5 %) LITA segments. Between 120 and 300 min after the beginning of the experiment, the reaction was maximum and amounted up to 300 % control reaction, then decreased. First, with respect to in vitro research isolated by LITA rings, while analyzing the results of the research, one should take into consideration the possibility that during the research, the functional state of the tissues changes and in particular its sensitivity to depolarization of the cell membrane. Second, the change in the sensitivity to depolarization of the cell membrane of the smooth muscles' LITA might be the potential mechanism causing the occurrence of the postoperative spasm after the CABG treatment.

True Aneurysm of the Left Internal Thoracic Artery.

Aneurysms of the internal thoracic artery (ITA) are rare and can have many etiologies. Hyperflow is an exceptional etiology. We report the case of a 56-year-old woman who presented with a stress-induced ischemia of the left arm. Computed tomography angiography showed occlusion of the subclavian artery and a true aneurysm of the ITA. The ITA aneurysm was resected without restoration of the ITA continuity and a carotid-subclavian bypass was performed. Pathological examination of the aneurysm sac was not specific.

Cabrol-Type Aortocoronary Anastomosis Technique in Coronary Artery Bypass Surgery.

BACKGROUND: In conventional coronary artery bypass grafting (CABG), multiple anastomoses in the ascending aorta are needed for multiple coronary targeting. We have introduced a single-site proximal anastomosis technique for multiple coronary targeting. A single anastomosis between the ascending aorta and graft was performed using a side-to-side maneuver (Cabrol type). Additionally, the graft was connected to another graft by end-to-end anastomosis for the coronary artery on the opposite side. We evaluated the long-term clinical outcome and graft patency of this Cabrol-type aortocoronary anastomosis technique. METHODS: From 2002 to 2012, a total of 483 patients (mean age, 64.6 years) underwent CABG using our Cabrol-type aortocoronary anastomosis technique. The average number of target coronary arteries per person was 3.4 ± 0.6. The mean follow-up duration was 74.2 ± 31.3 months; 98.7% of hospital survivors completed the follow-up. Postoperative coronary computed tomography angiography was performed in 377 patients (81.8%). RESULTS: Operative mortality was 4.6%. The actuarial overall survival rates at 1, 5, and 10 years were 97.8 ± 0.7%, 89.3 ± 1.5%, and 69.0 ± 3.9%, respectively. The actuarial major adverse cardiac and cerebrovascular event-free survival rates at 1, 5, and 10 years were 95.7 ± 0.9%, 80.1 ± 2.0%, and 60.8 ± 3.7%, respectively. One- and 5-year patency rates of the Cabrol-type aortocoronary graft were 81.1 ± 2.2% and 61.3 ± 3.6%, respectively. CONCLUSION: Our Cabrol-type aortocoronary anastomosis technique did not have superior clinical outcomes and graft patency compared with conventional CABG. However, this technique might be an alternative option in select patients with atherosclerotic disease of the ascending aorta, or other embarrassing situations.

The impact of ligation of proximal side branches on blood flow and functional status of the internal thoracic artery in coronary anastomosis.

BACKGROUND: The effect of proximal side branches on the patency of the internal thoracic artery (ITA) is controversial. We used echocardiography and Doppler to verify the effect of ligation of branches on the flow and coronary flow reserve (CFR) of the grafted ITA in patients after coronary artery bypass grafting (CABG). METHODS: We prospectively investigated 53 patients with preserved left ventricular ejection fraction (LVEF >50%) who underwent CABG of the ITA. In Group I (25 patients), major branches were ligated during ITA anastomosis to the left anterior descending (LAD) coronary artery, whereas no ligation was performed in Group II (28 patients). Systolic flow (SF), diastolic flow (DF), and total flow (TF = SF + DF) were measured by Doppler echocardiography at the proximal level of the ITA preoperatively, at early postoperative stage, and 6 months after surgery. Dobutamine stress echocardiography (DSE) was performed at 6 months to determine CFR. RESULTS: The ITA flow was predominantly systolic before surgery and diastolic in the postoperative period. We found no differences between the groups in DF. On DSE, SF (19.5±9 mL/min vs 32.7±19 mL/min; P=.003) and TF (79±21 mL/min vs 101±47 mL/min; P=.037) were higher in Group II. There were no differences in CFR (1.9±0.46 vs 2.11±0.56; P=.143). CONCLUSION: In patients with preserved LVEF, ligation of major side branches during anastomosis to the LAD does not alter ITA flow or CFR.

Vertebral and internal mammary artery steal syndrome in patients with hemodialysis access.

BACKGROUND: Increased flow in the subclavian artery feeding a vascular access for hemodialysis can induce steal phenomena in the vertebral (VA) and internal mammary artery (IMA). The aim of this study was to describe the hemodynamic effects of access flow on the VA and IMA in patients with native fistulas and grafts. PATIENTS AND METHODS: Peak systolic (PSV) and end diastolic (EDV) velocity measurements of the VA, IMA and carotid arteries, as well as flow volume measurements of the subclavian artery, were performed. Flow measurements at the side of the vascular access were compared with the contralateral side. Fifty-five patients were consecutively included, most with a radio-cephalic fistula on the left arm with a mean shunt volume of 1156 ml/min. RESULTS: Pathologic flow patterns were observed in the ipsilateral VA in four patients (7.3 %); contralateral VA flow was normal in all patients. Peak systolic velocity of the VA was significantly decreased at the side of the shunt arm with a PSV of 42.6 ± 11.8 cm/s compared to 48.4 ± 15.6 cm/s contralateral (p < 0.05). The IMA flow pattern were normal in all patients. The PSV of the IMA was significantly decreased (p < 0.01) at the side of the shunt arm (87.5 ± 29.1 cm/s) compared to the non-shunt arm (95.9 ± 27.4 cm/s). CONCLUSION: We describe significant hemodynamic effects of fistulas to the vertebral and internal mammary arteries. Doppler spectral analysis of the vertebral and internal mammary arteries should be integrated in ultrasound, especially in patients with cerebrovascular or cardiac symptoms.

Transit-time flow measurement as a predictor of coronary bypass graft failure at one year angiographic follow-up.

BACKGROUND: Transit-time flow measurement (TTFM) is a commonly used intraoperative method for evaluation of coronary artery bypass graft (CABG) anastomoses. This study was undertaken to determine whether TTFM can also be used to predict graft patency at one year postsurgery. METHODS: Three hundred forty-five CABG patients with intraoperative graft flow measurements and one year angiographic follow-up were analyzed. Graft failure was defined as more than 50% stenosis including the "string sign." Logistic regression analysis was used to analyze the risk of graft failure after one year based on graft vessel type, anastomatic configuration, and coronary artery size. RESULTS: Nine hundred eighty-two coronary anastomoses were performed of which 12% had signs of graft failure at one year angiographic follow-up. In internal mammary arteries (IMAs), analysis showed a 4% decrease in graft failure odds for every 1 mL/min increase in TTFM (OR = 0.96, CI = [0.93; 0.99], p = 0.005). ROC analysis showed good discriminative ability for TTFM alone AUC = 69.5% in IMA grafts. For single-vein grafts the decrease in graft failure odds was 2% for every 1 mL/min increase in TTFM (OR = 0.98; CI = [0.97; 1.00], p = 0.059) and AUC of 59.9%. There were no significant relationships between TTFM and graft failure in other graft types or graft configurations. CONCLUSION: The TTFM method has good discriminative ability for assessing the risk of graft failure in certain graft types within the first year after CABG surgery and is a valuable instrument for intraoperative quality assessment of bypass grafts.

Optimal treatment of unligated side branch of internal mammary artery: Coil, amplatzer vascular plug or graft stent? A case report and literature review.

Coronary artery steal syndromes may occur following coronary artery bypass grafting as a result of the presence of large side-branches arising from the internal mammary artery (IMA). Coil embolization, Amplatzer Vascular Plug and graft stents are all used for the treatment of such syndromes. The literature contains limited data on the long-term success of these treatment methods. There is no large series regarding occluded IMA side branches causing coronary steal phenomena, and data on long-term follow-up of this treatment method is also very limited. This report presented two cases and their treatment, and reviewed the advantages and disadvantages of treatment methods and the factors that affect successful treatment.