Patent Left Internal Mammary Artery Research Articles

Resolution of Iatrogenic Aortic Dissection Illustrated by Computed Tomography

An 83-year-old man with known history of known coronary artery disease (prior coronary artery bypass surgery and percutaneous coronary intervention), hypertension, and hypercholesterolemia presented with ongoing exertional angina and dyspnea despite medical therapy. A dipyridamole rubidium-82 stress test showed moderate-sized ischemia in the inferior and inferolateral territory. An echocardiogram showed mild segmental left ventricular dysfunction with an ejection fraction of 45% and mild mitral regurgitation. Angiography showed severe native triple vessel disease, patent left internal mammary artery graft to left anterior descending artery, patent stents in saphenous vein graft to obtuse marginal, and occluded vein graft to right coronary artery (RCA; previously known to be occluded). The native RCA was diffusely diseased with subtotal occlusions in its mid and distal segments including severe proximal posterior descending artery disease and was partly collateralized from obtuse marginal (Figure 1A). Given the ongoing symptoms on medical therapy, decision was made to proceed with percutaneous coronary intervention to RCA. Figure 1. RCA angiographic appearance: preprocedure (A), contrast in the false lumen of the aortic root dissection originating from RCA ostium (image at the time of ostial stent deployment) (B), and final angiographic appearance (C). The RCA ostium was engaged with an 8F Amplatz (AL 0.75) guide (chosen for extra support in a calcified, diffusely diseased artery), and the total occlusions in the mid and distal RCA were crossed using a PT Graphix guide wire (Boston Scientific, Natick, Mass). Rotational atherectomy with 1.50-mm burr was performed to …

Comparison of graft patency for off-pump and conventional coronary arterial bypass grafting using 64-slice multidetector spiral computed tomography angiography

Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years and its use is increasing frequently, but it remains an open question whether OPCAB provides similar patency to conventional coronary artery bypass graft (CCABG) surgery with cardiopulmonary bypass. The present study assessed the graft patency in patients that had coronary arterial bypass grafting (CABG) performed on-pump and off-pump. A total of 237 patients with CABG performed by a single surgeon were retrospectively studied, in which 100 patients underwent CCABG and 137 patients underwent OPCAB; the two groups were well matched according to relative factors and no significant differences were found in both groups. Postoperatively, systematic assessment on the graft patency of all the patients was conducted with 64-slice multidetector spiral computed tomography angiography (MSCTA) at one month, 1 year, 2 years, 3 years and 4 years, respectively, to provide 641 grafts for analysis. Patency of left internal mammary artery (LIMA) was higher than that of saphenous vein (SVG) in both groups; no significant difference was seen in LIMA patency and SVG patency in both groups. Results of 64-slice MSCTA indicate that OPCAB provides similar patency to CCABG surgery with CPB.

Percutaneous Revascularization Is the Preferred Strategy for Patients With Significant Left Main Coronary Stenosis

In the early 1970s, coronary artery bypass graft (CABG) was found to improve late survival in comparison to medical therapy in patients with significant left main stenosis.1–3 Once CABG became the standard of care for left main disease, a distinction between “protected”—by at least 1 patent bypass graft to the left coronary artery—and “unprotected left main (UPLM)”— no patent bypass graft to the left coronary artery—was made. In the 1980s, early attempts at balloon angioplasty of UPLM stenoses were associated with poor early outcomes because of coronary dissection, abrupt closure, and restenosis. Mortality rates as high as 30% at 1 year were reported.4–6 In the 1990s, bare metal stents were introduced and soon used to treat UPLM disease. Several small registries found a low rate of procedural complications, but repeat revascularization rates of 20% to 30% because of restenosis were considered unacceptable.7–12 Early bare metal stent registries for UPLM also found high mortality rates, particularly in high-risk patients, such as patients with acute coronary syndromes and poor left ventricular function. Importantly, high-risk subgroups often presented with late sudden death after stenting.11,13 In the early 2000s, the introduction of drug-eluting stents (DES), with the promise of vastly reduced rates of restenosis,14–17 raised the possibility of improved late outcomes in this challenging patient group. Response by Smith p 1033 Clinical outcomes after treatment of UPLM disease with either the sirolimus-eluting stent or the paclitaxel-eluting stent from >20 small registries have been published. Results reported in these registries vary widely.18–40 As depicted in Table 1, cardiac mortality between 6 and 12 months after the procedure ranges from 0% to 11%. Target lesion revascularization (TLR) or target vessel revascularization (TVR) rates range from 2% to 38%. This wide variation in clinical outcome appears largely because of variation …

Late thrombotic occlusion of a left internal mammary artery graft causing ST-elevation myocardial infarction

Late occlusion of the left internal mammary artery (LIMA) is rare, and its pathological basis is unknown. We present a case of acute occlusion of the LIMA in a 77-year-old woman, 7 years after graft surgery, causing fatal myocardial infarction. Diagnostic angiography of the LIMA revealed a proximal occlusion just beyond the LIMA origin which re-canalised after repeated injection of contrast with near complete restoration of LIMA patency and flow with smooth angiographic appearance. Despite initial diminution of pain and electrocardiographic changes with recanalisation, pain and ST changes returned and the patient died. Restoration of near normal vessel patency with angiography suggests that the basis of this occlusion is not atherosclerotic plaque rupture, but is more likely to represent in situ thrombosis or, less likely, localized spasm. Early recognition of the possibility of LIMA occlusion may direct initial angiography to the LIMA rather than the native circulation, and reduce the time to reperfusion.

Systemic Hyperkalemia for Cardiac Arrest on CPB with or without Cross‐Clamping

Myocardial protection may be compromised in situations with a patent left internal mammary artery (LIMA) graft or an unclamped aorta. Because of collateral coronary blood flow, electrical arrest may not be achieved. Currently, hypothermia is often used to augment myocardial protection and provide cardiac arrest in these situations. We report a simple, novel technique of systemic hyperkalemia during cardiopulmonary bypass to achieve rapid and complete electromechanical arrest. By providing complete diastolic arrest, uniform myocardial protection is ensured.

Mitral valve repair in redo cardiac surgery.

An increasing number of patients are being referred for mitral valve repair in the redo cardiac surgery setting. The most common clinical scenarios involve prior coronary bypass surgery or aortic valve replacement, each presenting special challenges in terms of gaining valve exposure to enable repair while limiting dissection as much as possible. A right anterior thoracotomy approach is preferred in most patients, coupled with hypothermic fibrillatory arrest. A repeat sternotomy may be favored in select circumstances such as when there is a need for bypass grafting or moderate aortic insufficiency is present. Special attention to cannulation techniques, perfusion conditions, valve exposure, and de-airing maneuvers are all important to ensure good clinical results. Using a tailored approach we have performed mitral valve repair in 22 patients with a patent left internal mammary artery graft following coronary artery bypass grafting between July 1992 and February 2000 with acceptable morbidity and low mortality.

Can the Left Subclavian Artery be Safely Covered during Endovascular Repair of the Descending Thoracic Aorta?

: Routine preoperative carotid-subclavian bypass or transposition is frequently recommended in patients undergoing endovascular repair of the descending thoracic aorta (DTA). We reviewed our comprehensive thoracic endografting experience with regards to coverage of the left subclavian artery (LSA) to assess whether mandatory preoperative carotid-subclavian bypass or transposition is necessary. : Between February 2000 and November 2005, 255 patients were successfully treated with an endoluminal graft (ELG) to the DTA. Indications for intervention included atherosclerotic aneurysms (109/255, 42.7%), acute and chronic dissections (75/255, 29.4%), miscellaneous (41/255, 16.1%), and penetrating aortic ulcers (30/255, 11.8%). There were 151 males (151/255, 59.2%) and 104 females (104/255, 40.8%) with a mean age of 71 years (range, 23-91 years). : The LSA was completely covered with an ELG in 71 patients (71/255, 27.8%) and partially covered in 47 patients (47/255, 18.4%). In patients who had complete coverage of the LSA, 30 patients (30/71, 42.3%) had acute or chronic Type B dissections, 26 patients (26/71, 36.6%) had aneurysms, 11 patients (11/71, 15.5%) had miscellaneous aortic pathologies, and 4 patients (4/71, 5.6%) had pseudoaneurysms associated with prior coarctation repair. Fifteen patients (15/255, 5.9%) underwent preoperative carotid-subclavian bypass or transposition and subsequently underwent complete coverage of the LSA with an ELG. One patient (1/56, 1.8%) with complete coverage of the LSA required elective postoperative carotid-subclavian bypass secondary to left arm claudication. : Routine preoperative carotid-subclavian bypass is not necessary, except in select patients with a patent left internal mammary artery to the left anterior descending artery bypass graft or contralateral vertebral artery disease.

Impact on Contrast, Fluoroscopy, and Catheter Utilization from Knowing the Coronary Artery Bypass Graft Anatomy Before Diagnostic Coronary Angiography

To what extent the unavailability of coronary artery bypass graft (CABG) anatomy complicates the performance of diagnostic coronary angiography has not been studied. The medical and catheterization records and coronary angiograms of 367 consecutive CABG surgery patients who underwent 394 diagnostic coronary angiographic studies from October 1, 2004, to May 31, 2007, were retrospectively reviewed. The patients' mean age was 65+/-9 years, and 97% were men. The mean interval from CABG surgery to angiography was 8.3+/-6.1 years. Patent left internal mammary artery grafts were found in 75%, and the mean number of patent grafts was 2.1+/-1.0. Compared with angiograms with known CABG anatomy, angiograms with unknown CABG anatomy (26%) required significantly higher amounts of contrast (189+/-7 vs 158+/-4 ml), longer fluoroscopy times (14.0+/-0.7 vs 10.6+/-0.4 minutes), and more diagnostic catheters (3.0+/-0.1 vs 2.5+/-0.05) (p<0.001 for all comparisons). The unavailability of CABG anatomy remained associated with increased contrast, fluoroscopy, and catheter use after multivariate adjustment. Proximal anastomotic bypass markers were associated with lower contrast use but were seen in only 9% of patients. In conclusion, the unavailability of CABG anatomy significantly and independently increases the use of contrast, fluoroscopy, and catheters during diagnostic coronary angiography. Every effort should be made to obtain CABG anatomy before diagnostic angiography is performed.

Coronary Steal Due to Bilateral Internal Mammary Artery—Pulmonary Artery Fistulas: A Rare Cause of Chest Pain After Coronary Artery Bypass Grafting

A 54-year-old man with a history of coronary artery bypass grafting (CABG) presented with chest pain and was found to have non-ST-segment elevation myocardial infarction. Left heart catheterization with coronary angiography demonstrated 100% occlusion of the right internal mammary artery (IMA) to the right coronary artery graft in its midsegment and a patent left IMA to the left anterior descending graft. An unusually large extensive fistulous collateral formation was observed between the right IMA and the left IMA to the pulmonary arterial system, causing left to right shunting. His angina was attributed to substantial coronary steal caused by the shunt. The patient refused any further intervention or surgery and opted for medical treatment. As a complication of CABG, IMA to pulmonary artery (PA) fistulas are rare. Thus far, more than 20 cases have been reported; most have been unilateral. This is the second reported case to date of bilateral IMA-PA fistula formation after CABG. An IMA-PA fistula should be considered in the differential diagnosis of patients presenting with chest pain after CABG and can be diagnosed by selective angiography of IMA grafts.

Hybrid Coronary Revascularization

Hybrid coronary revascularization combines left internal mammary artery (LIMA) to left anterior descending artery (LAD) grafting integrated with percutaneous coronary intervention (PCI) on stenoses in the non-LAD territories. Hybrid coronary revascularization offers multivessel revascularization with minimal morbidity in high risk patients. Usually hybrid coronary revascularization performs minimally invasive direct coronary artery bypass grafting (MIDCAB) without cardiopulmonary bypass. The concept is now 10 year old. This procedure has been developed from MIDCAB plus percutaneous transluminal coronary angioplasty (PTCA) to totally endoscopic coronary artery bypass grafting (TECAB) procedures plus PTCA and drug-eluting stenting (DES). The hybrid coronary revascularization procedure may be especially useful in complex LAD lesions, restenotic lesions in LAD, acute myocardial infarction in “non-LAD” territory, high-risk elderly patients with multiple comorbidities and patients with severe left ventricular systolic dysfunction who are not ideal candidates for conventional bypass surgery. Hybrid coronary revascularization results according to the literature are very attractive. LIMA patency rates were found to be in the 98% range and restenosis rates in the PCI part of the procedure are in a 12% range.16) The wider introduction of hybrid revascularization is limited chiefly by the high number of repeat interventions compared with off-pump coronary artery bypass grafting, which occurs because of the target vessel failure rate of percutaneous coronary intervention. Drug-eluting stents substantially decrease the reintervention rate. However, the future role of hybrid coronary revascularization is unclear in patients with multivessel coronary artery disease involving the LAD if comparable results may be attained with multivessel PCI.

Can Late Supraclavicular Echo Doppler Reliably Predict Angiographical String Sign of Lima to Lad Area Grafts?

To investigate whether supraclavicular ultrasonography of left internal mammary artery (LIMA) to left anterior descending (LAD) area grafts can reliably predict (distal) string sign grafts on arteriography. Fifty-five patients (42 M, 61 +/- 7 years) with the LIMA to LAD area grafting were prospectively studied. Control arteriography was performed at 1.4 +/- 0.8 years postoperatively. Angiography demonstrated in 46 patients (group I) functional grafts, in 4 patients (group II) sequential distal string sign grafts and in 5 patients (group III) total string sign grafts. Ultrasonography was performed at 1.8 +/- 0.8 year postoperatively and compared with control angiography. Data were tested by unpaired t- and ANOVA tests. The diagnostic accuracy was assessed by the area under the curve of the Receiver Operator Characteristic. A formula was developed to predict the probability of (distal) string sign phenomena of sequential as well as single LIMA grafts. Between the groups all duplex parameters showed a highly significant linear relation (p < or = 0.004) and all parameters between group I and III are significantly different with high Area Under Curve values. The model for the probability of (distal) string sign grafts fitted best with diastolic and systolic peak velocities as the most discriminative factors for (distal) string sign grafts. Postoperative supraclavicular duplex as a method to assess the patency of LIMA to LAD area grafts allows discriminating functional grafts from (distal) string sign grafts.

A Non-Biased Assessment of the Usefulness of Computed Tomographic Angiography

The report by Shapiro et al1 on the accuracy of computed tomographic angiography (CTA) is a breath of fresh air in an area of cardiac imaging that is based more on financial self-interest and flashy marketing than on science. The investigators compared the results of CTA with direct coronary angiography and found that this technique is accurate when the amount of calcium is small. However, patients with minimal calcification tend to have normal coronary arteries or less severe disease, and presumably, standard techniques for identifying the presence of significant coronary obstructions would suffice in this group, without exposure to the higher dose of radiation associated with CTA.

Detection of Patency of Internal Mammary Artery Grafts to the Left Anterior Descending Artery by Transthoracic Doppler Echocardiography

To determine whether a coronary artery bypass graft (CABG) is patent, we examined the flow of the left internal mammary artery (LIMA) to the left anterior descending artery (LAD) by transthoracic Doppler echocardiography (TTDE). Eighty-seven patients with CABG (LIMA to distal LAD) were enrolled in the study. The flows from each subject were analyzed by three criteria: mosaic flow at the anastomosis site, distal anterograde flow (ante flow), and proximal retrograde flow (retro flow). On angiography, 79 grafts were patent and eight were not. TTDE study of 79 patent grafts demonstrated mosaic, ante, and retro flow in 63 (79.7%), 74 (93.7%), and 35 grafts (49.4%), respectively. The averaged diastolic peak velocity of ante flow was 26.3 +/- 11.0 cm/sec, significantly higher than that (4.8 +/- 7.1 cm/sec, P < or = 0.0001) in eight patients without patent grafts. These eight patients had no mosaic or retro flow and only three had ante flow. The accuracies to predict patency were 81.6%, 90.8%, and 49.4% for mosaic, ante, and retro flows, respectively. The existence of mosaic, retro, or sufficient ante flows strongly indicated the patency of LIMA to the LAD. When symptoms are possible to be derived from the occlusion of CABG to LAD, TTDE is a promising method to examine whether a LIMA to LAD bypass is patent.

Integrated Coronary Revascularization

Robotic totally endoscopic coronary artery bypass (TECAB) of the left anterior descending artery (LAD) coupled with percutaneous coronary intervention (PCI) of a second coronary artery has been investigated in patients with multivessel disease to provide a minimally invasive therapeutic option. TECAB of the LAD was performed using the left internal mammary artery (LIMA). A second lesion was treated with PCI before surgery, simultaneously, or after surgery. Three-month angiographic follow-up was performed in all patients and was subject to independent review. A total of 27 patients requiring double vessel revascularization were treated at 7 centers. Eleven patients underwent PCI before surgery, 12 patients underwent PCI after surgery, and 4 patients underwent simultaneous surgical and percutaneous intervention. Ten patients (37%) were treated with bare metal stents, whereas 17 patients (63%) were treated with drug-eluting stents. Postoperative angiographic evaluation demonstrated an overall LIMA anastomotic patency of 96.3% and PCI vessel patency of 66.7%. There were no deaths or strokes. One patient experienced a perioperative myocardial infarction. Eight of 27 patients (29.6%) required reintervention, 1 LIMA anastomotic stenosis (3.7%), 3 after bare metal stent (30%), and 4 after drug-eluting stent placement (23.5%). Integrated revascularization treatment plans provide minimally invasive options for patients with multivessel coronary artery disease. This approach may be accomplished with no mortality, low perioperative morbidity, and excellent angiographic LIMA patency. The reintervention rate after PCI in this series was higher than that reported elsewhere and should be investigated further. The choice of suitable vessel, type of stent and timing of the treatment must be carefully considered before implementing this hybrid strategy.

Aortic Arch Aneurysm and Patent Left Internal Mammary Artery: Technique of Transposition of Supra-aortic Vessels and Embolization of the Subclavian Artery

Endovascular treatment of aortic arch aneurysms poses unique problems because of vascularization of the carotid arteries. Transposition of supra-aortic vessels is becoming an established and accepted strategy for expanding the applicability of stent graft repair. left subclavian artery (LSA) is not usually transposed because its overstenting does not produce relevant complications. Nevertheless, some selected cases need high-pressure revascularization of the LSA, such as in the presence of a patent left internal mammary artery. We present a technique of revascularization of supra-aortic vessels and "balloon protected" embolization of the origin of the LSA.

Aortic Arch Aneurysm and Patent Left Internal Mammary Artery: Technique of Transposition of Supra-aortic Vessels and Embolization of the Subclavian Artery

Aortic Arch Aneurysm and Patent Left Internal Mammary Artery: Technique of Transposition of Supra-aortic Vessels and Embolization of the Subclavian Artery

The radial artery as a coronary bypass conduit: dealing with hyperreactivity

The radial artery as a coronary bypass conduit: dealing with hyperreactivity

Long-term patency of saphenous vein and left internal mammary artery grafts after coronary artery bypass surgery: Results from a Department of Veterans Affairs Cooperative Study

This study defined long-term patency of saphenous vein grafts (SVG) and internal mammary artery (IMA) grafts. This VA Cooperative Studies Trial defined 10-year SVG patency in 1,074 patients and left IMA patency in 457 patients undergoing coronary artery bypass grafting (CABG). Patients underwent cardiac catheterizations at 1 week and 1, 3, 6, and 10 years after CABG. Patency at 10 years was 61% for SVGs compared with 85% for IMA grafts (p < 0.001). If a SVG or IMA graft was patent at 1 week, that graft had a 68% and 88% chance, respectively, of being patent at 10 years. The SVG patency to the left anterior descending artery (LAD) (69%) was better (p < 0.001) than to the right coronary artery (56%), or circumflex (58%). Recipient vessel size was a significant predictor of graft patency, in vessels >2.0 mm in diameter SVG patency was 88% versus 55% in vessels </=2.0 mm (p < 0.001). Other positive significant predictors of graft patency were use of aspirin after bypass, older age, lower serum cholesterol, and lowest Canadian Functional Class (p < 0.001 to 0.058). The 10-year patency of IMA grafts is better than SVGs. The 10-year patency for SVGs is better and the 10-year patency for IMA grafts is worse than expected. The 10-year patency of SVGs to the LAD is better than that to the right or circumflex. The best long-term predictors of SVG graft patency are grafting into the LAD and grafting into a vessel that is >2.0 mm in diameter.

Crush stenting of bifurcational left subclavian‐vertebral artery stenosis

Left internal mammary artery (LIMA) has the best long-term patency in patients undergoing coronary artery bypass surgery. Stenosis of the proximal left subclavian artery (SA) may reduce flow to the LIMA, causing myocardial ischemia. We report a novel technique (crush stenting) for the treatment of a complex bifurcational left SA-vertebral artery (VA) stenosis in the presence of a patent LIMA bypass conduit. This technique limited plaque shifting, restored normal flow to all vessels, including the LIMA, and avoided devastating consequences of VA occlusion.

Fistulous connection between internal mammary graft and pulmonary vasculature after coronary artery bypass grafting: a rare cause of continuous murmur

A 58-year-old male who had undergone coronary artery bypass grafting (CABG) using left internal mammary artery and a sequential saphenous vein graft 2 years ago presented with new onset angina. His initial physical examination revealed an unexpected continuous murmur over the left sternal border, and two-dimensional echocardiography has failed to identy the cause. Cardiac catheterization then performed and revealed patent left internal mammary artery and saphenous vein grafts. Besides, selective injection of the left internal mammary artery graft also showed a fistula formation between left internal mammary artery graft and pulmonary vasculature of the left upper lobe. He was managed conservatively because of the severely diseased left anterior descending artery distal to internal mammary artery anastomosis and low pulmonary artery pressure. The development of fistulous connection between internal mammary artery and pulmonary vasculature is an extremely rare complication following CABG. Patients with such fistulae usually present with chest pain due to coronary steal syndrome. A new heart sound, especially a continuous murmur, may be detected during physical examination. Surgical correction is indicated in the event of refractory angina, growing fistula causing heart failure or endarteritis. Otherwise, a conservative approach with instruction of the patient for prophylactic precautions of subacute bacterial endocarditis may be recommended for asymptomatic patients.