Internal thoracic artery: Prevalence of atherosclerotic changes

Effect of skeletonisation and pedicled bilateral internal mammary artery grafting in coronary artery bypass surgery on post-operative wound infection: A meta-analysis

The results showed that different internal thoracic artery (ITA) was associated with the rate of postoperative wound infection and the severity of pain following coronary artery bypass grafting (CABG). In order to ascertain if there was any genuine difference in the rate of postoperative infection and severity of the pain, we conducted a meta-analysis to evaluate if there was any actual difference in the wound complication that had been identified with the ITA method. Through EMBASE, Cochrane Library and Pubmed, and so forth, we systematically reviewed the results by August 2023, which compared the impact of skeletonised versus pedicled internal mammary artery (IMA) on wound complications following CABG. The trial data have been pooled and analysed in order to determine if a randomisation or fixed-effect model should be applied. The meta-analysis of data was performed with Revman 5.3 software. The results of this meta-study included 252 related articles from four main databases, and nine articles were chosen to be extracted and analysed. A total of 3320 patients were treated with coronary artery transplantation. Based on current data analysis, we have shown that the rate of postoperative wound infections is reduced by the use of the skeletonised internal mammary artery (SIMA) (OR, 1.84; 95% CI, 1.13, 3.01; p = 0.01). But the results showed that there were no statistically significant differences in the post-operation pain score of the patients (MD, 0.09; 95% CI, -0.58, 0.76; p = 0.79). Furthermore, the duration of the operation was not significantly different between the SIMA and pedicled internal mammary artery (PIMA) (MD, 3.30; 95% CI, -3.13, 9.73; p = 0.31). Overall, the SIMA decreased the rate of postoperative wound infection in CABG patients than the PIMA.

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.

Long-Term Results of Bilateral Internal Thoracic Artery Grafting in Dialysis Patients

BACKGROUND

We evaluated the perioperative and long-term results of bilateral internal thoracic artery grafting in dialysis patients.

METHODS

One hundred one consecutive patients on chronic dialysis who underwent isolated coronary artery bypass grafting were retrospectively compared according to the surgical technique, bilateral internal thoracic artery (BITA) grafting (n = 76) or single internal thoracic artery (SITA) grafting (n = 25).

RESULTS

Hospital mortality was 5.3% in the BITA group and 8.0% in the SITA group (p = not significant). The incidence of mediastinitis was not different (7.9% in the BITA group and 8.0% in the SITA group). The median duration of follow-up was 3.1 years (range, 0.1 to 10.9). Survival and freedom from cardiac mortality were not different between the two groups, but the BITA group had a trend toward better results. Freedom from cardiac events (including cardiac-related death, myocardial infarction, percutaneous coronary intervention, redo coronary artery bypass grafting, and congestive heart failure) was superior in the BITA group (p = 0.03). Calcification of the ascending aorta, peripheral vascular disease, insulin-dependent diabetes mellitis, and age were the independent risk factors of late death.

CONCLUSIONS

Perioperative results of BITA grafting in dialysis patients were not different from the results of SITA grafting. However, the long-term results of BITA grafting in dialysis patients were better than the results of SITA grafting. Overall, our results support the continued use of BITA grafting in dialysis patients.

Disturbed endothelial function of the internal thoracic artery in patients with coronary artery disease

OBJECTIVES AND BACKGROUND

The internal thoracic artery is an established arterial graft for myocardial revascularization. It never had been investigated, whether there are functional differences in this vessel between patients with or without coronary artery disease.

METHODS

We investigated the left internal thoracic artery of 28 patients (15 with and 13 without coronary artery disease) with a duplex-system at rest and with a handgrip exercise.

RESULTS

Concerning the measured flow velocities at rest there was only a significant difference between the diastolic mean and peak velocity between the two groups, the other investigated parameters demonstrate no significant difference. The peak diastolic and the mean diastolic velocity was less in patients with coronary artery disease during the handgrip-test. The flow reserve was decreased in patients with coronary artery disease (12.6+/-24.0% vs. 32.3+/-30.9%, P < 0.05).

CONCLUSIONS

We demonstrated, that patients with coronary artery disease have a higher peripheral resistance and a lower diastolic velocity of the internal thoracic artery during stress testing. This corresponds to a disturbed vasomotion and may be an early marker of arteriosclerosis.

Vascular profile of patients with multivessel coronary artery disease

PURPOSE

Early and accurate diagnosis of peripheral atherosclerosis is of paramount importance for global management of patients with known coronary artery disease (CAD). We sought to retrospectively evaluate the clinical relevance of significant subclavian artery stenosis (SAS) and abdominal vessel stenosis or aneurysm (AVA) in patients undergoing coronary angiography.

SUBJECTS AND METHODS

Medical records of consecutive patients underwent coronary angiography at two public institutions over a 12-month period were evaluated. Angiographic results of patients underwent coincident diagnostic abdominal aorta angiography to evaluate abdominal vessels or subclavian angiography on the basis of clinical and angiographic criteria were analyzed.

RESULTS

During the study period, 724 consecutive patients (535 males, mean age 68.1+/-11 years) were enrolled (Table 2): a significant atherosclerotic disease of at least one arterial segments were observed in 198 patients (27.3%). Angiographically significant SAS was observed in 18/220 patients (8.1%) undergoing concomitant subclavian artery angiography and candidates to coronary surgery using the internal mammary artery. Ten patients with subclavian artery stenosis and upper limb ischemia underwent subclavian artery angioplasty and stenting and bypass surgery using LIMA. AVA were reported in 180 (35.7%) of 504 consecutive patients: renal artery stenosis was found in 13.1% of cases (66 patients), aortoiliac artery disease in 13.7 % (69 patients), and aortic aneurismal disease in 8.9% (45 patients). Logistic regression analyses revealed > or =3-vessel CAD (odds ratio [OR] 9.917, p=0.002), age>60 years old (OR 3.817, p=0.036), > or =3 risk factors (OR 2.8, p=0.048) as independent predictors of SAS and AVA.

CONCLUSION

Patients with multivessel CAD are frequently aged, have an high risk profile and multiple vascular atherosclerotic distributions, suggesting the usefulness of a more global and comprehensive cardiovascular approach.

Malpractice in Invasive Cardiology: Is Angiography of Abdominal Aorta or Subclavian Artery Appropriate in Patients Undergoing Coronary Angiography?

BACKGROUND

Identification of peripheral vascular disease by angiography in patients undergoing coronary angiography may be considered as malpractice but sometimes seems to be justified under clear entry criteria. The present mata-analysis is aimed to analyze the appropriateness and results of screening angiography of subclavian or abdominal aorta performed at the time of coronary angiography.

METHODS

A search of published literature for peripheral angiography in patients undergoing coronary angiography over the last 10 years was performed using the MEDLINE database. No language restriction was employed. Only studies enrolling more than 100 patients for abdominal aortography and 50 patients for subclavian/internal mammary artery angiography were considered. Reference lists from identified studies were also reviewed to identify other potentially relevant references.

RESULTS

Twenty-nine studies were retrieved: 8 articles about subclavian artery (SA) and internal mammary (IMA) angiography and 21 about renal (RA) and aortoiliac (AOI) angiography. The total number of patients enrolled was 27,936. Nine studies out of 29 were prospective. Defined entry criteria were reported in 24 out of 29 studies. Significant SA and IMA stenosis were reported in 5.5 and 9% of patients, respectively. RA stenosis >50% was present in 12.7% of patients with CAD. Finally, undetected AOI disease was reported in 35.5% of patients undergoing coronary angiography. Mean complication rate was 0.8 +/- 0.6%. Predictors of SA and IMA stenosis were unclear. Age, multi-risk profile, multi-vessel CAD, history of PVD or carotid disease, severe hypertension, unexplained renal dysfunction or decreased creatinine clearance have been reported most frequently as predictors of RA and AOI disease in patients undergoing coronary angiography.

CONCLUSIONS

Consistent evidence of appropriateness of renal angiography in selected patients undergoing coronary angiography have been produced in literature. IMA and AOI angiography seem to be not justified unless they are part of SA in patients scheduled for arterial conduit with brachial differential pressure, thoracic irradiation or surgery, or of abdominal angiography to detect RA stenosis in laboratories with radiological digital peripheral equipment.

Early clinical and angiographic outcome of the pedicled right internal thoracic artery graft to the left anterior descending artery

BACKGROUND

The left internal thoracic artery (LITA) graft to the left anterior descending (LAD) artery became the gold standard graft in coronary surgery. Subsequently, the right internal thoracic artery (RITA) graft was increasingly used. However, there is still some debate about the optimal way of using this conduit. The aim of the present study was to assess our experience in grafting the pedicled RITA graft to LAD in 212 consecutive patients.

METHODS

The records of 212 consecutive patients who underwent isolated coronary artery bypass grafting with the pedicled RITA graft to the LAD artery at Harefield Hospital between January 1998 and May 2001 were retrospectively reviewed. We approached the last 35 consecutive patients to obtain an angiographic control group. All 35 patients (16.5%) consented and, before discharge, underwent angiography to look at the quality of anastomoses and the patency of grafts.

RESULTS

Successful catheterization and engagement of the RITA grafts was performed in 32 patients. Angiography showed that 32/32 (100%) of the RITA grafts were widely patent with excellent flow. The distal anastomoses of these RITA grafts were also satisfactory. There were no deaths among the study patients.

CONCLUSIONS

Our results show that the use of the pedicled RITA graft to the LAD artery provides a good early clinical and angiographic outcome, and suggests that the pedicled RITA graft to the LAD artery is a good alternative to the pedicled LITA graft to the LAD artery.

An unusual case of left internal mammary artery ostial disease: clarifying role of intravascular ultrasound

Stenosis at the origin of the left internal mammary artery graft is rare. We present a case with a suspected stenosis involving the origin of the left internal mammary artery that conventional angiography failed to demonstrate convincingly. Intravascular ultrasound illustrated a severe stenosis and the patient underwent successful stenting of the left internal mammary artery origin. The intravascular ultrasound finding of a dissection flap, just distal to the left internal mammary artery origin, suggests that local trauma to the vessel from prior catheterization procedures may have been responsible for the progressive narrowing at the left internal mammary artery ostium.

Lambda graft with the radial artery or free left internal mammary artery anastomosed to the right internal mammary artery: flow dynamics

BACKGROUND

The aim of this study was to evaluate the outcome and flow dynamics of the lambda graft configuration, relative to a second arterial graft.

METHODS

From 1998 to 2000, 47 patients (mean age 55.5 +/- 4.7 years) with triple-vessel disease underwent arterial revascularization using the lambda graft. The in situ left internal mammary artery (LIMA) and right internal mammary artery (RIMA) were anastomosed to the left anterior descending (LAD) and obtuse marginal arteries, respectively. In 21 patients (group I) presenting proximal or middle-third LAD or right coronary (RC) arterial stenoses, the lambda graft was constructed by anastomosing the distal LIMA, as a free LIMA graft, to the RC and proximally to the in situ RIMA. In the other 26 patients (group II) presenting with middle-distal third LAD or RC arterial stenoses, the radial artery (RA) was used to construct the lambda graft. All patients underwent transthoracic echo color Doppler before and after an adenosine test at 1 week and 3 months after operation.

RESULTS

There were no hospital deaths. Overall, 47 lambda grafts were constructed. There was no difference between baseline and maximal flows and coronary flow reserve (CFR) between groups. CFR at IMA stems increased in both groups within 3 months versus 1 week [(LIMA)CFR = 2 +/- 0.3 vs 2.3 +/- 0.3 (p = 0.002) and (RIMA)CFR = 2.2 +/- 0.4 vs 2.5 +/- 0.3 (p = 0.009) in group I, and (LIMA)CFR = 2.12 +/- 0.33 vs 2.4 +/- 0.35 (p = 0.005) and (RIMA)CFR = 2.17 +/- 0.32 vs 2.52 +/- 0.26 (p = 0.001) in group II]. At 3 months versus 1 week, the (RIMA)diameter(i) (mm) at rest was 1.69 +/- 0.32 versus 1.48 +/- 0.2 (p = 0.015) in group I and 1.66 +/- 0.3 versus 1.47 + 0.2 (p = 0.01) in group II. At 6 +/- 2.4 months, all patients were free of angina.

CONCLUSIONS

These data, almost identical for free LIMA and RA to RIMA using the lambda graft, demonstrate that RIMA flow reserve is adequate for multiple coronary anastomoses irrespective of the second arterial graft.

Percutaneous transluminal angioplasty of ostial lesions of internal mammary artery grafts

The internal mammary artery (IMA) is currently the best graft for coronary bypass surgery and is therefore preferentially anastomosed to major arteries, usually the left anterior descending (LAD) artery. This graft may develop a stenosis, most often at the distal anastomosis. Ostial stenoses are rare and their pathophysiology uncertain. While angioplasty of distal anastomotic lesions provides adequate results, the very small number of published cases of angioplasty of ostial lesions explains the lack of knowledge on results of this type of procedure. The authors report six procedures of this type on five patients, including two with stenting. The primary success rate was 100%, with only one hospital complication in the form of pulmonary edema. Mean follow-up for 35 months revealed one sudden death due to probable restenosis, another death 3 years after angioplasty from rapid fatal shock without complementary investigation, and one case of unstable angina secondary to intrastent restenosis. These results suggest that this type of angioplasty is technically feasible with low risk, and that the restenosis rate seems relatively high, potentially presenting as sudden death, in the same way as unprotected dilatation of the native left main artery. A very close clinical follow-up of these patients is therefore necessary, with angiographic control in case of suspected ischemia.

The impact of chronic renal failure on atherosclerosis of the internal thoracic arteries

BACKGROUND

Little is known about the impact of renal failure on atherosclerotic changes in the internal thoracic artery (ITA).

METHODS

A total of 20 consecutive patients on chronic dialysis who underwent coronary artery bypass grafting (CABG) during April 1998 through September 1999 were investigated. The 20 control patients were selected from the same interval to rigorously match risk factors. Atherosclerosis of the ITA collected from each patient was analyzed using the subjective evaluation proposed by Kay and colleagues.

RESULTS

There were no cases of greater than 25% atherosclerotic luminal narrowing among a total of 35 ITA specimens from dialysis patients. The degree of atherosclerosis was not significantly different from that of the specimens from matched patients (p = 0.18). No calcification was found in ITA grafts either microscopically or macroscopically. The number of elastic lamellae, an index of the elasticity of the ITA graft, was not significantly different from those obtained from the matched patients. Analysis of preoperative coronary angiography revealed that coronary calcification was significantly more frequent in dialysis patients (15 patients, 75%) than in matched patients (p < 0.05). By analysis of postoperative angiography in dialysis patients, no evidence of atherosclerotic changes was found in 28 opacified ITAs. In addition, despite the presence of calcification in the native coronary, no calcification was evident along the entire length of the ITAs.

CONCLUSIONS

This study revealed the minimal impact of chronic renal failure on atherosclerotic changes in the ITA. The results of this study support the continued use of ITA grafting in dialysis patients.

Right Y-graft, a new surgical technique using mammary arteries for total myocardial revascularization

BACKGROUND

We report a new technique that consists of a right Y-graft using only skeletonized internal mammary arteries (IMA) for total arterial myocardial revascularization.

METHODS

This technique consists of anastomosing the in situ left IMA (LIMA) and right IMA (RIMA) to the left anterior descending and obtuse marginal artery, via the transverse sinus, respectively. The distal free LIMA was anastomosed to the right coronary artery and afterwards in a Y fashion to the RIMA stem. Eleven patients with triple-vessel disease underwent coronary artery bypass grafting using this technique. Postoperatively and at follow-up all patients underwent color Doppler contrast-enhanced transthoracic echocardiography (TTE) before and after an adenosine provocation test.

RESULTS

Overall, 33 IMA-coronary anastomoses were made and 11 right Y-grafts were constructed. At 1 week after operation color Doppler contrast-enhanced TTE before and after the adenosine provocation test, respectively, showed an increase in LIMA stem diameter of 0.31 mm and in mean flow 62 mL/min. Coronary flow reserve (CFR) was 2+/-0.3. The increase in RIMA stem diameter was 0.2 mm and in mean flow was 121.7 mL/min. Coronary flow reserve was 2.5+/-0.4. Only 1 patient demonstrated an anomalous Doppler pattern, suggesting a partial Y-graft closure.

CONCLUSIONS

Such a technique permits total myocardial revascularization using only mammary arteries and left ventricular perfusion from both IMAs simultaneously. The color Doppler contrast-enhanced TTE is a rapid, accurate, and noninvasive test allowing a good assessment of IMA patency.

Elective stenting of a de novo ostial lesion of the right internal mammary artery

Elective stenting for severe stenosis involving the origin of a right internal mammary artery graft was performed in a 60-year-old patient with severe unstable angina 2 yr after surgical revascularization. The procedure had an excellent immediate result which persisted at 6-mo angiographic follow-up. This unusual localization of arterial narrowing will probably be increasingly recognized as the right internal mammary artery becomes a first-choice conduit for right coronary artery bypass.

Pathology of the radial and internal thoracic arteries used as coronary artery bypass grafts

BACKGROUND

This investigation compared the incidence and the degree of atherosclerosis present in radial artery (RA) and internal thoracic artery segments remaining after coronary artery bypass grafting.

METHODS

One hundred seventy specimens from 102 patients were histologically analyzed, including 106 RA specimens.

RESULTS

The mean degree of pathology for the RA was 0.89 on a 0 (none) to 4 (lumen completely obliterated) scale; the mean grade of pathology for the internal thoracic artery was 0.30 (p < 0.001). Presence of diabetes, aortofemoral disease, femoral-popliteal disease, age, and male gender correlated with an increase in RA pathology. Flow in the in situ RA did not correlate with the degree of pathology.

CONCLUSIONS

Study of the excess RA and internal thoracic artery segments remaining after coronary artery bypass grafting demonstrated that the RA had a higher degree of atherosclerosis than the internal thoracic artery at the time of harvest. Overall severity of disease in the RA was low. The long-term performance of RA grafts will determine whether this level of atherosclerotic disease has any clinical significance.

Conduit options in coronary artery bypass surgery

The choice of graft conduit is crucial to the success of coronary artery bypass grafting (CABG) because the patency of a coronary conduit is closely associated with an uneventful postoperative course and a better long-term patient survival. The standard conduits used for CABG are the greater saphenous vein (GSV) and the internal thoracic artery (ITA). An excellent substitute conduit for coronary bypass operations that can be taken "off the shelf" is certainly the dream of every practicing cardiac surgeon. However, virtually every synthetic and biologic alternative to arterial conduits or autologous fresh saphenous vein has proved disappointing. Fortunately, patients with absolutely no autologous conduit alternatives are uncommon. Circumstances exist, however, that often necessitate the use of alternative conduits such as young hyperlipemic patients, absent or unsuitable autologous ITAs and GSV as a result of previous myocardial revascularization, peripheral arterial reconstruction, and varicose vein ligation procedures. This review provides an update on the clinical work done with all coronary conduits available for myocardial surgical revascularization.