Internal mammary artery graft angioplasty: acute and long-term outcome

Percutaneous management of ostial stenosis of the left internal mammary artery graft

A 61-year-old man, who had undergone coronary artery bypass surgery 10 years earlier, presented with a non-ST segment elevation myocardial infarction. He was treated with medical therapy and taken to the Cardiac Catheterization Laboratory. A left heart catheterization demonstrated an ostial stenosis in the left internal mammary artery graft, which was felt to be the culprit lesion. This was successfully repaired with a drug eluting stent. This case is presented as an unusual location for a de novo coronary stenosis. The pathophysiology of these lesions is not well understood.

Preventing graft restenosis after coronary artery bypass grafting with tissue-type plasminogen activator

Objective

To explore the feasibility and safety of using tissue-type plasminogen activator (t-PA) to prevent graft restenosis after coronary artery bypass grafting (CABG).

Methods

In this prospective observational study, 37 patients underwent CABG between June 2009 and May 2013. These patients were grouped according to the anti-coagulation strategy after surgery: t-PA (n = 12) and conventional treatments (n = 25). In the t-PA group, the patients received acetylsalicylic acid (ASA) and clopidogrel plus intravenous infusion of t-PA (0.25 mg/kg/day) starting at 24 h after surgery and that lasted for 3 days. In the conventional group, the patients received only ASA and clopidogrel. 64-row spiral computed tomographic coronary angiography was performed at 1 week, 1, and 3 months after surgery to evaluate the patency of the graft vessel.

Results

The mean stenosis severity of the saphenous vein grafts was lower in the t-PA group compared with the conventional group at 3 months after surgery (p < 0.05), but there was no significant difference at 1 week and 1 month (p > 0.05). The patency rate of the grafts was not significantly different between the two groups at 1 week, 1, and 3 months after surgery (p > 0.05).

Conclusion

Early application of t-PA after CABG was feasible and safe, and might help prevent early restenosis of SV grafts. Additional clinical randomized trials are necessary to address this issue.

Immediate and Long-Term Results of Drug-Eluting Stents in Mammary Artery Grafts

Percutaneous intervention of a coronary graft is the treatment of choice when the graft fails. The objective is to report the long-term results of drug-eluting stents (DES) in mammary artery grafts (MAG). Patients who had been treated with DES for MAG in 27 centers were selected. The baseline and procedural clinical data were included prospectively, and the follow-up was performed with the patients, families, and medical records. Two hundred and sixty-eight patients were included: age 65.5 ± 10.1 years, diabetes 47.8%, ejection fraction 55.5 ± 14.9%.

INDICATION

stable angina 28.4%, unstable angina 38.1%, non-ST-elevation myocardial infarction 21.6%, ST-elevation myocardial infarction 5.3%, and heart failure 6.7%; 1.19 ± 0.59 stents/patient were implanted measuring 18.8 ± 8.8 mm in length and 2.68 ± 0.35 mm in diameter. Rapamycin was used in 78 cases (29.1%), paclitaxel in 77 (28.7%), everolimus in 70 (26.1%), zotarolimus in 34 (12.7%), and biolimus in 9 (3.4%). All cases were successful except for 1 in which the patient died 30 minutes after the procedure. There were no other inhospital events. After a follow-up of 41 months (Q25: 23.7 to Q75: 57.8), 24 patients (9%) died of heart-related causes and 20 (7.5%) of noncardiac causes. Repeat revascularization was necessary in 31 cases, and in 1 additional patient, there was total occlusion, which was not treated. These 32 patients represented 11.9% of the total. In conclusion, the implantation of DES in MAG shows very high procedural success and also low long-term event rates.

Acute occlusion of the left internal mammary artery graft in the late postoperative period

The left internal mammary artery (LIMA) graft used in coronary artery bypass grafting (CABG) reliably revascularizes the left anterior descending artery (LAD) and has excellent long-term patency. Here, we report a rare case of ST-elevation myocardial infarction caused by acute occlusion of the LIMA in the late postoperative period. A 62-year-old man who underwent CABG for a myocardial infarction 15 years previously was transferred to our hospital for the recurrence of acute anterior myocardial infarction. Emergent cardiac catheterization revealed complete occlusion from the mid-portion of the LIMA to the LAD. We successfully treated this patient with primary stent implantation to the culprit LIMA lesion using intravascular ultrasound guidance. <Learning Objective: The left internal mammary artery (LIMA) is commonly used as the conduit to bypass the left anterior descending artery (LAD) and has shown excellent long-term patency. However, we have experienced a rare case with acute myocardial infarction due to acute occlusion of LIMA in late postoperative period. We should carefully monitor, considering that the LIMA could possibly undergo arteriosclerotic changes.>.

Distal anastomotic lesions after coronary artery bypass surgery: incidence, pathogenesis, and treatment approach

Distal anastomotic lesions are the most common reason for venous and arterial graft failure. Redo coronary artery bypass surgery carries a higher risk for mortality and non-fatal myocardial infarction. Many operators therefore consider percutaneous coronary intervention as a good alternative for relieving angina symptoms in this subset of patients with anastomotic lesions. However, the best percutaneous method for treating these lesions is still controversial. Here we review reported data on the incidence, pathogenesis, and treatment of distal anastomotic lesions in both venous and arterial bypass grafts.

Resistance of the Internal Mammary Artery to Restenosis: A Histomorphologic Study of Various Porcine Arteries

BACKGROUND/AIMS

Restenosis after percutaneous transluminal angioplasty (PTA) of the internal mammary artery (IMA) grafts is much less pronounced than in other arteries and venous grafts. The aim of the study was to test whether various arteries respond differently to dilatation.

METHODS

PTA of the IMA, carotid, renal and circumflex coronary (RCx) arteries was performed in 9 pigs (balloon to artery ratio of 1:1.5). After 8 weeks, angiography was repeated and vessels prepared for histological analysis. Immunohistochemical staining was done to examine proliferative activity (Ki67) and to identify the vasa vasorum of the adventitia (F VIII-RA).

RESULTS

The intima-media ratio after PTA was lowest in the IMA (0.06), followed by the carotid (0.27) and renal arteries (0.49) and the RCx (0.69). Proliferation of the intima was seen at 287 degrees of the vessel circumference in the RCx, at 286 degrees in the renal and at 166 degrees in the carotid artery. No proliferative activity was seen in the IMA. The intima-adventitia ratio was lower in the IMA than in the RCx and renal arteries (p < 0.05).

CONCLUSION

Intima proliferation after PTA varies between the different vessels, with best results seen in the IMA. There are differences in remodeling after PTA between muscular, muscular/elastic and elastic arteries.

Drug-eluting stents for the percutaneous treatment of the anastomosis of the left internal mammary graft to left anterior descending artery

BACKGROUND

Data on the treatment of left internal mammary to left anterior descending artery (LIMA-to-LAD) anastomotic disease are scarce and not homogeneous. Both surgery and percutaneous interventions (PCI) have been attempted, but the most effective treatment has not yet been established. In particular, should PCI be performed, the role of stenting seems to be limited by less favorable results than in other subsets of lesions.

OBJECTIVE

To assess the clinical impact of drug-eluting stent (DES) use in this particular subset of lesions.

METHODS

We describe a cohort of patients treated with PCI on LIMA-to-LAD anastomoses, reporting acute 1-year clinical and angiographic outcomes. The clinical impact of DES use was evaluated as the requirement for target lesion revascularizations (TLR).

RESULTS

Fifty-six consecutive patients were evaluated. Acute procedural success was achieved in 52 patients (92.8%). Plain balloon angioplasty allowed acute procedural success in 15 patients (28.8%), whereas stenting was required in 37 patients (71.2%) with suboptimal results or to treat complications. Bare-metal stents (BMS) were used in 17 and DES in 20 patients, without differences in acute results. One-year clinical follow-up was available in 96.1% of patients. TLR were needed in 17.3% of patients. No significant differences were detected in TLR rates after treatment with BMS and DES (26.6% vs. 25%; P=0.99). Two late stent thromboses were observed after DES deployment.

CONCLUSION

PCI of the stenoses of LIMA-to-LAD anastomoses with DES did not provide any clinical improvement over BMS use in long-term outcomes; DES use was associated with some cases of late thrombosis.

Successful angioplasty and stenting of bilateral internal mammary artery grafts from the left radial approach. Case report and review of the literature

We describe a case of successful percutaneous transluminal coronary angioplasty and stenting from the left radial approach in a patient with effort angina due to two tight stenoses at the distal anastomosis site of the internal mammary artery grafts. The left radial approach has several advantages compared with the conventional femoral approach: a lower rate of vascular complications and an easier vascular access to the left internal mammary artery graft. The distance from the access site to the origin of the artery is shorter and involves less angulation than the femoral approach. The radial approach is not only safe but it enables faster patient mobilisation and seems also useful in reducing management costs with a hospital stay that can be reduced to 6 h in low-risk cases.

Long drug-eluting stent implantation for a diffusely diseased right internal mammary artery

The frequent use of the internal mammary artery as a bypass graft has brought about an increasing need for angioplasty to treat stenotic arterial grafts. Percutaneous interventions of internal mammary artery grafts by balloon angioplasty or stenting with bare-metal stents have been described in the past. However, implantation of bare-metal stents was associated with high rates of restenosis. The introduction of drug-eluting stents for the treatment of diseased native coronary vessels has been associated with a reduced need for repeat intervention compared with bare-metal stents for both low-risk lesions and high-risk, complex lesions, including the 'long lesion' subset. We describe a case of long drug-eluting stent implantation for a diffusely diseased right internal mammary artery.

Mobile stenosis in a left internal mammary artery graft: a case report

The authors report a case of percutaneous transluminal angioplasty (PTA) with coronary stent for stenosis in a left internal mammary artery (IMA) graft, which led to newly developed stenosis at both sides of the stent in the IMA graft. The intravascular ultrasound (IVUS) revealed that the stenotic lesion consisted of intramural hematoma, which had shifted owing to the stent deployment. They suggest that the cause of stenotic lesions in IMA grafts at the early postoperative period is luminal compression by intramural hematoma, which can be visualized by use of IVUS. The strategy of PTA for IMA grafts performed at the early postoperative period should include consideration for hematoma shift.

Impact of internal mammary artery conduit on long-term outcomes after percutaneous intervention of saphenous vein graft

BACKGROUND

The influence of an internal mammary artery (IMA) graft on long-term outcomes after percutaneous saphenous vein graft (SVG) intervention is currently unknown.

METHODS AND RESULTS

To examine the impact of IMA on outcomes in patients undergoing SVG interventions, we analyzed 2119 patients from the Duke Cardiovascular Disease Database (1986-2003) with prior coronary artery bypass surgery undergoing cardiac catheterization who had at least 1 SVG graft. Patients were categorized into 4 groups: group I, SVG intervention and patent IMA; group II, no SVG intervention and patent IMA; group III, SVG intervention without patent IMA; and group IV, no SVG intervention without patent IMA. At a median follow-up of 4.8 years (interquartile range, 2.1 to 8.8 years), adjusted survival rates in groups I, II, III, and IV were 72.8%, 72.3%, 64.5%, and 58.9%, respectively. Multivariate Cox proportional hazards modeling showed similar survival for groups I and II (P=0.63) and for groups III and IV (P=0.33). The presence of IMA graft was related to lower long-term mortality (adjusted hazard ratio [HR], 0.69; 95% CI, 0.58 to 0.82), whereas SVG intervention was not associated with long-term mortality (adjusted HR, 0.94; 95% CI, 0.81 to 1.10). In contrast, the adjusted event-free rates for nonfatal myocardial infarction were lower in the SVG intervention groups (groups I and III) than in the non-SVG intervention groups (groups II and IV) (HR for SVG intervention versus no SVG intervention, 3.19; 95% CI, 2.18 to 4.66), with the presence of patent IMA conferring no significant benefit on this outcome (HR, 1.37; 95% CI, 0.91 to 2.08).

CONCLUSIONS

In patients undergoing SVG interventions, survival, but not nonfatal myocardial infarction, is favorably influenced by the presence of patent IMA. In contrast, SVG intervention had no measurable survival benefit but was associated with an increased risk of nonfatal myocardial infarction.

Endovascular Control of Patent Internal Thoracic Artery Graft in Aortic Valve Surgery

Aortic valve replacement in patients who underwent previous coronary artery bypass with a patent internal thoracic artery is often a challenge because of the risk of graft injury during dissection or difficulties to obtain optimum myocardial protection. Different approaches to myocardial protection or internal thoracic graft dissection and control have been described. Endovascular control of the internal thoracic graft by an angioplasty balloon catheter positioned in the operating room before the operation can be a safe and simple alternative. We report the case of a patient who underwent this technique for aortic valve replacement.

Angioplasty of the internal thoracic artery bypass-graft an alternative to reoperation

BACKGROUND

This review presents an overview of interventional revascularization procedures of the internal thoracic artery after prior implantation as a coronary-artery bypass graft.

METHODS

Our search was concentrated on the MEDLINE-database to identify all articles on internal thoracic artery-graft-angioplasties and reoperation after internal thoracic artery bypass grafting published between 1968 and 2000.

RESULTS

Surgical revascularization and reoperation were reported in five papers including a total of 785 patients. The overall mortality of these patients was 4.2%. The presence of a patent internal thoracic artery-graft at the time of reoperation was not a risk factor for higher morbidity and mortality. Revascularization with percutaneous transluminal coronary angioplasty of the internal thoracic artery or the native left anterior descending artery via the internal thoracic artery-graft used as a conduit was performed in 327 patients. The primary success rate was 87%, the angiographically assessed rate of restenosis was 30% and the rate of complications approximately 1%.

CONCLUSIONS

In spite of technical problems the percutaneous transluminal coronary angioplasty in or via internal thoracic artery-graft presents a safe and feasible option to be recognized before a potential reoperation.

Results of angioplasty (with or without stent) at the site of a narrowed coronary anastomosis of the left internal mammary artery graft or via the internal mammary artery

During the past 6 years, 50 patients underwent percutaneous transluminal coronary angioplasty (PTCA) of a narrowed coronary anastomosis of a left internal mammary artery (LIMA) graft or PTCA of a left anterior descending coronary artery stenosis via LIMA grafts at the investigators' institution. The success rate was high at 88%. Thirty-four of the 44 successfully treated patients (77%) underwent repeat angiography, which showed restenosis in 14 patients (41%). In cases of stent implantation at the coronary LIMA graft anastomosis angioplasty site, the restenosis rate was 80%, but it was only 14% in cases of pure balloon dilation (p = 0.001). Therefore, in cases of coronary LIMA graft anastomosis, stent implantation should be avoided, because it implicates an excessively high restenosis rate.

Clinical outcomes following stent implantation in internal mammary artery grafts

We evaluated our experience with percutaneous coronary intervention (PCI) of internal mammary artery (IMA) grafts. From the institution's database we identified 288 patients with 311 IMA lesions. Of these, 82 (26.4%) had stents placed during PCI. Angiographic success was 92%. Mortality at 1 month was 1.7%, myocardial infarction (MI) 15.7%, and target lesion revascularization (TLR) 0.4%. Cumulative 1-year event rates were mortality 6.4%, MI 20.4%, and TLR 8.0%. TLR rates were significantly higher in the stented lesions than lesions treated with angioplasty alone (19.2% vs. 4.9%; P = 0.004). The higher TLR rate in stented lesions was most apparent at the anastomotic site (25.0% vs. 4.2%; P = 0.006). Percutaneous revascularization of IMA grafts can be performed safely with high procedural success and excellent short- and long-term results. Stenting, particularly at the anastomotic site, was associated with significantly greater rates of TLR than angioplasty alone.

The VB-1 catheter: an improved catheter for difficult-to-engage internal mammary artery grafts

As patients with prior coronary artery bypass grafting age, internal mammary artery grafts are more frequently encountered in the cardiac catheterization laboratory. Angiography and interventions involving these grafts are often difficult, particularly in patients with tortuous subclavian anatomy and/or proximal internal mammary artery origins. We describe a new catheter shape, the Cordis Behar Internal Mammary, VB-1, which allows selective intubations of both right and left internal mammary arteries that are not possible with conventional catheters.

Percutaneous interventions in radial artery grafts: clinical and angiographic outcomes

In the modern era, radial artery graft is being used with increasing frequency to replace saphenous vein as a conduit for coronary artery bypass surgery. Several reports have shown encouraging early results of radial grafts compared to saphenous grafts. Despite these advantages, radial artery graft failure requiring revascularization does occur. We report on the clinical, angiographic, and technical characteristics and the follow-up results of 22 patients who underwent percutaneous intervention of radial grafts.

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.

Comparison of event and procedure rates following percutaneous transluminal coronary angioplasty in patients with and without previous coronary artery bypass graft surgery [the ROSETTA (Routine versus Selective Exercise Treadmill Testing after Angioplasty) Registry]

To compare 6-month post-percutaneous transluminal coronary angioplasty (PTCA) outcomes and cardiac procedure use among patients with and without prior coronary artery bypass graft (CABG) surgery, we examined 791 patients who were enrolled in the Routine versus Selective Exercise Treadmill Testing after Angioplasty (ROSETTA) Registry. The ROSETTA Registry is a prospective, multicenter registry that examines the use of functional testing after successful PTCA. Most patients were men (76%, mean age 61 +/- 11 years) who underwent single-vessel PTCA (85%) with stent implantation (58%). Baseline and procedural characteristics differed between patients with a prior CABG (n = 131) and patients with no prior CABG (n = 660), including Canadian Cardiovascular Society angina class III to IV (60% vs 49%, respectively, p = 0.03) and stenosis involving the proximal left anterior descending coronary artery (10% vs 22%, p = 0.004). Event rates among patients with prior CABG were higher than among patients with no prior CABG, including unstable angina (19% vs 11%, p = 0.02), myocardial infarction (2% vs 1%, p = 0.2), death (4% vs 2%, p = 0.08), and composite clinical events (22% vs 12%, p = 0.003). Furthermore, patients with prior CABG had higher rates of follow-up cardiac procedures, including angiography (24% vs 14%, p = 0.008) and PTCA (13% vs 7%, p = 0.04), but not repeat CABG (2% vs 3%, p = 0.8). A multivariate analysis that included baseline clinical and procedural characteristics demonstrated that prior CABG was a significant independent predictor of clinical events and cardiac procedure use (odds ratio 2.3, 95% confidence interval 1.5 to 3.5, p = 0.0001). Within the prior CABG group, patients with a PTCA of a bypass graft had a higher composite clinical event rate than patients with a PTCA of a native vessel (32% vs 17%, p = 0.05). In contrast, patients with a PTCA of a native vessel had event rates similar to those of patients with no prior CABG (17% vs 12%, p = 0.2). Thus, post-CABG patients have an increased risk of developing a cardiac event or needing a follow-up cardiac procedure during the 6 months after PTCA.

Brachytherapy for in-stent restenosis through the internal mammary artery

We report five cases treated with brachytherapy through the internal mammary artery (IMA) for in-stent restenosis at the distal anastomosis (n = 3) and in the left anterior descending coronary artery beyond the distal anastomosis (n = 2). After angioplasty, catheter-based gamma radiation was performed. There was no delivery failure of the radiation system. All cases had angiographic success and no procedural or in-hospital complications.

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.

Reoperative revascularization of a left internal mammary artery ostial stenosis

A severe ostial stenosis of the left internal mammary artery graft was responsible for unstable angina in a patient with a previous coronary artery bypass graft. Successful revascularization of the lesion was achieved with a subclavian artery-to-left internal mammary artery bypass using a saphenous vein conduit. This procedure was performed through a left thoracotomy incision to avoid potential hazards of a redo median sternotomy.

Percutaneous revascularization of the internal mammary artery graft: short- and long-term outcomes

OBJECTIVES

We evaluated the short- and long-term clinical outcomes after percutaneous revascularization of the internal mammary artery (IMA) graft.

BACKGROUND

Previous reports in a relatively small number of patients have indicated the safety of balloon angioplasty for the treatment of stenoses in the IMA graft. However, the use of alternative interventional techniques and their long-term results have not yet been evaluated.

METHODS

We analyzed the in-hospital and one-year clinical outcomes of 174 consecutive patients who underwent percutaneous revascularization of 202 lesions located in the IMA graft, by either balloon angioplasty or stenting.

RESULTS

Anastomotic lesions were evident in 128 cases (63%), and they were more commonly treated with balloon angioplasty (116/128, 91%), whereas lesions located at the ostium (n = 16, 8%) were more frequently treated with stents (11/16, 69%). Procedural success was 97% with excellent in-hospital outcome: 0.6% mortality rate, no Q-wave myocardial infarction (MI) and 0.6% rate of urgent bypass surgery. Cumulative one-year rates were: mortality 4.4%, MI 2.9% and target lesion revascularization (TLR) 7.4%.

CONCLUSIONS

Revascularization of the IMA graft can be performed safely, with high procedural success and a low rate of in-hospital complications. Long-term follow-up showed very low TLR rate.