Long-term serial angiographic studies after coronary artery bypass surgery

Arterial grafts do not counteract target vessel occlusion

OBJECTIVES

Grafted, non-occluded coronary arteries might contribute substantially to the myocardial blood supply and serve as a basis for vascular collateralization which preserves the myocardium in the event of graft occlusion. Early studies indicated that grafting with saphenous vein, but not internal mammary arteries, accelerates coronary atherosclerosis. This has not been extensively studied for the radial artery, which like the internal mammary artery (IMA) is largely resistant to atherosclerosis. A differential effect of various grafts might facilitate identification of disease-modifying principles. Our surgical cohort represented an opportunity to analyse new native coronary occlusions by comparison with preoperative angiograms.

METHODS

One hundred and two patients underwent angiography 1.3-3.9 years after coronary artery bypass surgery, primarily in order to compare the patency of radial artery, IMA and saphenous vein grafts.

RESULTS

Out of 290 stenotic, grafted vessels, 67 (23%) occluded during follow-up. Native occlusion occurred in 47% of the patients and correlated with serum-cholesterol. In a per target analysis, independent predictors of postoperative native occlusion were the right coronary artery territory, patent corresponding graft, the corresponding graft being an IMA and end-to-side anastomosis.

CONCLUSIONS

Target vessel occlusion is similar with radial artery and saphenous vein grafts and proceeds rapidly even in the current era of secondary prophylaxis against atherosclerosis. Competitive graft flow appears to promote occlusion. Contrary to previous studies, we do not find vein grafts to be inferior to IMA grafts with respect to preservation of native vessel patency.

Saphenous vein graft failure after coronary artery bypass surgery: pathophysiology, management, and future directions

OBJECTIVE

To review our current understanding of the epidemiology and pathogenesis of vein graft failure (VGF), give an overview of current preventive and interventional measures, and explore strategies that may improve vein graft patency.

BACKGROUND

VGF and progression of native coronary artery disease limit the long-term efficacy of coronary artery bypass graft surgery.

METHODS

We reviewed the published literature on the pathophysiology, prevention, and/or treatment of VGF by searching the MEDLINE (January 1, 1966-January 1, 2012), EMBASE (January 1, 1980-January 1, 2012), and Cochrane (January 1, 1995-January 1, 2012) databases. In addition, we reviewed references from the selected articles for studies not identified in the initial search. Basic science and clinical studies were included; non-English language publications were excluded.

RESULTS

Acute thrombosis, neointimal hyperplasia, and accelerated atherosclerosis are the 3 mechanisms that lead to VGF. Preventive measures include matching and quality assessment of conduit and target vessel, lipid-lowering drugs, antithrombotic therapy, and cessation of smoking. Treatment of VGF includes medical therapy, percutaneous intervention, and redo coronary artery bypass graft surgery. In patients undergoing graft intervention, the use of drug-eluting stents, antiplatelet agents, and embolic protection devices may improve clinical outcomes.

CONCLUSIONS

Despite advances in management, VGF remains one of the leading causes of poor in-hospital and long-term outcomes after coronary artery bypass graft surgery. New developments in VGF prevention such as gene therapy, external graft support, fully tissue-engineered grafts, hybrid grafts, and synthetic conduits are promising but unproven. Future efforts to reduce VGF require a multidisciplinary approach with a primary focus on prevention.

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.

The composite aortic wall graft technique: an option for a short coronary artery bypass graft

SUMMARY

During coronary artery bypass graft (CABG) surgery, the saphenous vein is sutured through its proximal segment to the aorta. Intimal hyperplasia is one of the possible causes of graft occlusion. Notably, blood turbulence can induce wall shear stress that may also play an important role in this process.

OBJECTIVE

We propose a new technique for performing proximal anastomosis to avoid CABG failure.

METHOD

An 80 kg pig was subjected to open heart surgery. Four stitches were placed in the anterior ascending aorta, which formed a 2 cm by 4 cm patch. This patch was isolated through the application of a tangential clamp that was oriented parallel to the axis of the aorta. After releasing the patch, which was held to the aorta through its cranial end pedicle, the rims were sutured to each other creating a conduit with a length of 4 cm and an internal diameter of 4 mm. The rest of the aortotomy was closed by placing a direct suture between its rims.

RESULT

This novel technique created an "in situ" aortic wall graft that was 4 cm long and characterized as being of uniform 4 mm caliber.

Clinical correlates of long-term mortality after percutaneous interventions of saphenous vein grafts

BACKGROUND

Increasing number of patients undergo percutaneous intervention of saphenous vein grafts (SVGs). However, the clinical factors associated with long-term mortality after SVG interventions are currently less known. Accordingly, the goal of present study was to evaluate clinical correlates of long-term mortality and to develop a simple bedside tool for risk stratification in patients undergoing SVG interventions.

METHODS

We analyzed 1019 patients undergoing SVG interventions from the Duke Cardiovascular Disease Database (1986-2003). Cox proportional hazards model was used to identify baseline variables associated with long-term mortality, and the model variables were then used to construct a nomogram for survival probability at 4 years.

RESULTS

At a median follow-up of 4 years, 24% of those undergoing SVG interventions died (interquartile range 2-7 years). Independent correlates of death at follow-up on multivariable analysis included presenting heart rate (hazard ratio [HR] 1.02, 95% CI 1.01-1.03), diabetes (HR 1.73, 95% CI 1.37-2.18), presenting heart failure (HR 1.62, 95% CI 1.27-2.06), age (per 10-year increase, HR 1.29, 95% CI 1.13-1.46), peripheral vascular disease (HR 1.59, 95% CI 1.23-2.04), renal insufficiency (HR 2.01, 95% CI 1.36-2.97), patent internal mammary graft (HR 0.67, 95% CI 0.53-0.86), body mass index < or = 25 kg/m2 (HR 0.91, 95% CI 0.85-0.97), carotid bruit (HR 1.44, 95% CI 1.12-1.85), S3 ventricular gallop (HR 1.83, 95% CI 1.11-3.03), and hypertension (HR 1.38, 95% CI 1.04-1.83) (c-index 0.83). Bootstrap validation confirmed excellent internal validity of the model (mean c-index 0.84, 95% CI 0.80-0.85).

CONCLUSION

Long-term survival after SVG intervention is poor, with one fourth of patients dying at median follow-up of 4 years. The nomogram developed using the model variables provides a method for clinicians to advise patients undergoing SVG interventions regarding their long-term prognosis, thereby enhancing discharge and long-term follow-up planning and setting up of realistic expectations.

Non-invasive half millimetre 32 detector row computed tomography angiography accurately excludes significant stenoses in patients with advanced coronary artery disease and high calcium scores

OBJECTIVE

To show an overall diagnostic accuracy > or = 90% for detection of > or = 50% stenoses by coronary half millimetre 32 detector row computed tomography angiography (32 x 0.5-MDCTA) in patients with advanced coronary artery disease (CAD) and a high likelihood of raised calcium scores.

METHODS

ECG gated 32 x 0.5-MDCTA (32 x 0.5 mm cross sections, 0.35 x 0.35 x 0.35 mm3 isotropic voxels, 400 ms rotation) was performed after injection of iodixanol (120 ml, 320 mg/ml) in 30 consecutive patients (25 men, mean (SD) age 59 (13) years, body mass index 26.2 (4.9) kg/m2). Native arteries, including > or = 1.5 mm branches, and bypass grafts were screened for > or = 50% stenoses. Stents were excluded. Conventional coronary angiography (performed 18 (12) days before 32 x 0.5-MDCTA) was analysed by quantitative coronary angiography.

RESULTS

Median Agatston calcium score was 510 (range 3-5066). Sensitivity, specificity, and positive and negative predictive values for detection of > or = 50% stenoses in native arteries were 76% (29 of 38), 94% (190 of 202), 71% (29 of 41), and 96% (190 of 199), respectively. Overall diagnostic accuracy was 91% (219 of 240). Due to the following artefacts 20% (69 of 352) of the vessels were excluded: motion, noise, and low contrast enhancement isolated or in combination (45 of 69 (65%)); image distortion by implantable cardioverter-defibrillator or pacemaker leads (18 of 69 (26%)); and blooming secondary to severe calcification (6 of 69 (9%)).

CONCLUSIONS

Coronary 32 x 0.5-MDCTA accurately excludes > or = 50% stenoses in patients with advanced CAD and high calcium scores with an overall diagnostic accuracy of 91%.

Drug-eluting stenting is superior to bare metal stenting in saphenous vein grafts

This study compared the outcomes of percutaneous coronary intervention (PCI) of saphenous vein grafts (SVGs) with drug-eluting stents (DES) with bare metal stents (BMS). PCI of degenerated SVG is associated with worse outcomes and high incidence of in-stent restenosis compared with PCI of native coronary arteries. There is a paucity of data on the outcomes of PCI of SVG with DES. Data from 223 consecutive patients who underwent PCI of SVG were imputed into a dedicated clinical database. We assessed the clinical outcomes at a mean follow-up of 9.1+/-2.1 months. A total of 139 patients underwent PCI of SVG with DES and 84 patients with BMS. The mean age of the SVG was 7.6+/-3.8 years in the DES group and 7.7+/-2.8 years in the BMS group (P=0.38). Procedural success was achieved in all patients except for one patient in the BMS group who underwent emergent coronary artery bypass graft surgery for SVG dissection. There were no other in-hospital cardiac events in both groups. There was one cardiac death in the DES group and three deaths in the BMS group (P=0.03). When compared to the BMS, PCI of SVG with DES was associated with a lower incidence of myocardial infarction (4.3% vs. 20.2%; P=0.04) and target vessel revascularization (10.1% vs. 36.9%; P=0.035). When compared with BMS, PCI of SVG with DES was associated with a lower incidence of death, myocardial infarction, and target vessel revascularization.

Embolic protection devices

The limiting factor in coronary artery bypass surgery is the relatively rapid progression of atheromatous disease in the saphenous vein grafts. Greater than one-half of these vein grafts will fail by 10 years, and the risks associated with repeat coronary artery bypass surgery are significantly greater than that of the initial surgery. Yet, catheter-based interventional treatment of saphenous vein grafts is hindered by distal embolization of friable lipidrich plaque. This is one mechanism responsible for reduced antegrade flow (i.e., "no-reflow" phenomenon), including spasm of the distal microcirculation and platelet clumping. This complication increases the risk of a major adverse clinical event (i.e., myocardial infarction or late mortality). Distal protection devices are designed to provide protection of the distal microcirculation during percutaneous intervention. One device type is a balloon occlusive system that temporarily occludes the distal vessel during the intervention followed by the aspiration of liberated atheromatous and thrombotic material before it reaches the arteriolar and capillary bed. The other device type is a nonocclusive, filter-based system that preserves coronary blood flow through tiny pores, as low as 100 microns. Atheromatous and thrombotic material is trapped in the filter-based systems and then removed with the retrieval of the device through a retrieval catheter. This article discusses the current distal protective devices.

Long-term clinical outcome after endoluminal reconstruction of diffusely degenerated saphenous vein grafts with less-shortening wallstents

OBJECTIVES

This study was designed to evaluate the immediate and long-term clinical results of patients undergoing endoluminal reconstruction in diffusely degenerated saphenous vein grafts (SVGs) with elective implantation of one or more less-shortening Wallstents.

BACKGROUND

The optimal treatment strategy for patients with diffusely degenerated SVGs is controversial. Endoluminal reconstruction by stent implantation is one proposed strategy; however, there are few data regarding long-term clinical outcome.

METHODS

Between May 1995 and September 1998, 6,534 consecutive patients underwent angioplasty in our institution, including 440 who were treated for SVG lesions. Of these, 126 (115 men, 11 women, median age 69.5 years, range: 33-86 years) with old SVGs (mean age: 13+/-5 years) diffusely degenerated stenosed or occluded (mean lesion length: 27+/-12 mm) were treated electively with implantation of one or multiple (total 197) less-shortening Wallstents.

RESULTS

Before discharge, 13 patients (10.3%) sustained at least one major cardiovascular event, including 4 deaths (3.2%), 11 myocardial infarctions (MI) (8.7%), and 3 repeat revascularizations (target vessel = 1, nontarget vessel = 2, 2.4%). Surviving patients were followed for 22+/-11 months: 13 patients (11.1%) died, 11 (9.4%) sustained an MI, 37 underwent angioplasty (31.6%), and 4 (3.4%) underwent bypass surgery. The estimated three-year event-free survival rates (freedom from death, and freedom from death/MI/target vessel revascularization) were (mean +/- SE) 81.1+/-7.8% and 43.2+/-18.5%, respectively.

CONCLUSIONS

The long-term clinical outcome of patients undergoing endoluminal reconstruction in diffusely degenerated SVG is relatively poor, mainly because of a high incidence of death or MI and the frequent need for repeat angioplasty. It is unlikely that percutaneous intervention alone will provide a satisfactory or definitive solution for these patients.

Progression of atherosclerosis after venous coronary artery bypass graft surgery: a 15-year follow-up study

We investigated the influence of progression of atherosclerosis on clinical outcome in a cohort of 428 consecutive patients with isolated venous coronary artery bypass graft surgery followed prospectively for 15 years. In 189 patients 307 repeat coronary angiograms were performed because of recurrent signs of ischemia. Progression in the native coronary circulation only was found in 38 angiograms (12%), in both the native circulation and in venous grafts in 66 angiograms (21%), in venous grafts only in 135 angiograms (44%), and no progression was found in 68 angiograms (22%). In all the angiographies with a proven progression in the native coronary arteries, 40% was found to be distal to a vein graft insertion. In multivariate analysis the number of distal anastomoses predicts progression in both the native circulation and in venous grafts. Thus, progression is determined by the extensiveness of coronary artery disease at operation. Also, the interval between operation and repeat angiography predicts progression in the native circulation. We conclude that clinical outcome is also determined by progression in the native coronary circulation. Secondary prevention may, therefore, benefit not only the long-term result in patients with venous bypass grafts but probably also in patients with any type of coronary bypass surgery.

Long-term clinical outcome after stent implantation in saphenous vein grafts

OBJECTIVES

We sought to determine the role of stent implantation in vein grafts by evaluating the long-term clinical outcome and estimated event-free survival at 5 years in 62 patients and by comparing our data with those of other treatment modalities previously reported.

BACKGROUND

Patients with recurrent angina after coronary artery bypass graft surgery pose a problem. Stent implantation has been advocated in an effort to avoid repeat operation and to address the limitations of balloon angioplasty.

METHODS

Patients undergoing stenting of a vein graft were entered into a dedicated data base. They were screened for death, infarction, bypass surgery and repeat angioplasty. Procedure-related events were included in the follow-up analysis. Survival and event-free survival curves were constructed by the Kaplan Meier method.

RESULTS

A total of 93 stents (84 Wallstent and 9 Palmaz-Shatz) were implanted in 62 patients. During the in-hospital period seven patients (11%) sustained a major cardiac event: two deaths (3%), two myocardial infarctions (3%) and three urgent bypass surgeries (5%). The clinical success rate, therefore, was 89%. During the follow-up period (median 2.5 years, range 0 to 5.9), another five patients (8%) died, 14 (23%) sustained a myocardial infarction, 12 (20%) underwent bypass surgery, and 14 (23%) underwent angioplasty. The estimated 5-year survival and event-free survival rates (free from infarction, repeat surgery and repeat angioplasty) were (mean +/- SD) 83 +/- 5% (95% confidence interval [CI] 73% to 93%) and 30 +/- 7% (95% CI 16% to 44%), respectively.

CONCLUSIONS

The in-hospital outcome of patients who underwent stent implantation in a vein graft is acceptable, but the long-term clinical outcome is poor. It is unlikely that mechanical intervention alone will provide a satisfactory or definite answer for the patient with graft sclerosis over the long term.

Late patency of long saphenous vein bypass grafts to the anterior and posterior cerebral circulation

To evaluate the late results and the natural history of long saphenous vein bypass grafts (SVGs) between the extracranial and intracranial circulation, the authors retrospectively analyzed 202 consecutive SVGs performed at the Mayo Clinic from 1979 to 1992. The distal anastomosis was to the vertebrobasilar system in 98 patients and to the carotid artery system in 103 patients. Surgical indications were advanced cerebroocclusive disease in 63% (127 cases), giant aneurysm in 37% (74 cases), and neoplasm in one patient. In 125 patent SVGs follow-up information was obtained for longer than 1 year and in 23 patent SVGs it was over 10 years (maximum 13 years, median 6.5 years). Most of the graft failures (76%) occurred during the 1st year after surgery, with 42% of all graft failures found during the first 24 hours after operation. Late graft attrition occurred in only 10 patients (8%). Cumulative patency at 1 year was 86% +/- 3%, at 5 years 82% +/- 4%, and at 13 years 73% +/- 19%. Neurological worsening at the time of occlusion developed in 72% of patients with early occlusion, whereas 80% of patients with late graft occlusion had no new neurological symptoms. Long-term patency of SVGs for cerebral revascularization appears to be excellent, with an average failure rate of 1% to 1.5% per year following the 1st year after surgery. To minimize early graft thrombosis, meticulous attention must be paid to technical detail.

Aneurysm of saphenous vein graft to coronary artery presenting as non-Q-wave myocardial infarction secondary to mass effect

Large aneurysms (> 4 cm) of saphenous vein grafts (SVG) to coronary arteries are a rare complication of coronary artery bypass graft surgery (CABG). A 64-year-old male, status post-CABG 14 years ago, presented with dyspnea and diaphoresis. Pneumonia and non-Q-wave myocardial infarction (MI) were diagnosed. Cardiac catheterization and chest computed tomography demonstrated a 5 x 7-cm aneurysm of a SVG. At the time of surgery, the left internal mammary artery (grafted to the left anterior descending artery) was found to be stretched tautly over the aneurysm, resulting in impaired flow. The aneurysm was successfully resected. This is the first published case implicating a SVG aneurysm as the direct cause of a MI by mass effect.

Percutaneous transluminal coronary angioplasty in patients with prior coronary artery bypass grafting: ten years' experience

We evaluated the acute and long-term results of percutaneous transluminal coronary angioplasty in 140 patients with prior coronary artery bypass grafting treated over a 10-year period (1981-1991). Angioplasty was technically successful in 85% of 122 nonoccluded native vessels and in 86% of 50 saphenous vein grafts. Two patients (1.4%) had a myocardial infarction and there were three procedure-related deaths (2.1%). The cumulative probability of survival was 91.5% and 74.5% at 1 and 5 years, respectively. Survival free from myocardial infarction and repeat bypass grafting at 1 and 5 years was 77.3% and 53.9%, respectively. At census, 31% of the 117 survivors were asymptomatic, and 47% were improved by at least two angina grades. Coronary angioplasty provides an apparently safe and effective alternative method of revascularization in selected patients with prior coronary artery bypass grafting. This treatment strategy potentially avoids reoperation with its attendant risks.

Angiographic predictors of a rise in serum creatine kinase (distal embolization) after balloon angioplasty of saphenous vein coronary artery bypass grafts

Distal coronary embolization is thought to be increased in the balloon angioplasty of coronary by-pass vein grafts. One hundred fifty-five procedures of balloon angioplasty involving single vein graft dilatation were successfully performed. Distal coronary embolization was defined as an elevation of creatine phosphokinase greater than twice the preangioplasty value and positive MB fraction. Twenty procedures were found to have embolism by this definition. Forty preangioplasty angiograms were randomly selected from the remaining procedures and analyzed as a control group. Eight angiographic features were evaluated as possible risk factors for distal coronary embolization, i.e., diffusely diseased vein graft, presence of thrombus, ulcerated lesion surface, marked eccentricity, large plaque volume, lesion angulation, abrupt proximal face and ectasia. A diffusely diseased vein graft (p = 0.002), presence of thrombus (p = 0.006), irregular or ulcerated lesion surface (p = 0.007), large plaque volume (p = 0.02) and marked eccentricity (p = 0.03) were found to be important predictors by univariate analysis. A diffusely diseased vein graft and a large plaque volume were found to be important independent predictors by multivariate analysis. The presence of thrombus and an irregular or ulcerated lesion surface frequently coexist with a diffusely diseased vein graft. It is concluded that a diffusely diseased vein graft and a large plaque volume are important independent predictors of distal embolization, and thrombus and an ulcerated lesion surface are also important.

Palmaz-Schatz stent implantation in stenosed saphenous vein grafts: clinical and angiographic follow-up

Balloon-expandable stents may reduce the restenosis rate following coronary angioplasty. To evaluate this potential in saphenous vein grafts, 26 patients with 30 discrete stenoses underwent conventional balloon dilation and successful Palmaz-Schatz stent implantation as part of a multicenter trial. All patients had resolution of their angina following the procedure. In a mean 5-month follow-up period, 14 patients (54%, 16 lesions) had repeat arteriography; two patients (14%) developed recurrent ischemia ascribed to their venous grafts from in-stent restenosis (2 of 16 lesions, 13%). Two asymptomatic patients (8%) died: one from cardiac arrest (stent patent) and one from stroke (no autopsy). The clinical recurrence rate (cardiac death, myocardial infarction, bypass surgery, repeat angioplasty, or symptom recurrence) was 15%. These preliminary results show trends toward an improved primary success rate with combined vein graft angioplasty/stenting and a lower restenosis rate in stented saphenous vein grafts, but continuing follow-up will be needed to verify these observations.

Coronary angioplasty for medically refractory unstable angina in patients with prior coronary bypass surgery

Percutaneous transluminal coronary angioplasty (PTCA) has been applied with good results to selected patients with unstable angina and to selected patients who have had prior bypass surgery. The population with prior bypass and unstable angina has not been specifically evaluated. This report reviews the results of angioplasty of 45 vessels in 34 patients with medically refractory unstable angina and at least one prior bypass heart surgery. Of these 34 patients, 32 had rest angina; 14 had resting electrocardiographic changes, all 34 were on aspirin 325 mg QD, 31 were on a calcium blocker, 22 were on a beta blocker, 9 were on intravenous nitroglycerin, and 5 required intraaortic balloon counterpulsation for temporary stabilization. Angioplasty of a vein graft was attempted in 17 patients; the left internal mammary was attempted in 4 patients; 24 native coronary arteries in 15 patients were attempted; 3 of the native arteries were protected left main arteries. Of the LIMA angioplasties, 3 were successful; in the 1 unsuccessful case, the occluded anterior descending artery was opened. Of the 17 vein grafts, 16 were successful: 1 had an acute occlusive syndrome and went to surgery with a balloon pump and bail out catheter; his recovery was uneventful. Of the 24 native artery angioplasties, 22 were successful: one patient was technically unsuccessful in the only vessel attempted; he went to semiemergent surgery and recovered uneventfully. In the other, a right coronary lesion was successfully dilated, but an occluded anterior descending artery was not opened. There were no deaths or in-hospital myocardial infarctions.(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous transluminal angioplasty in patients greater than or equal to 5 years after their last coronary bypass graft surgery

Angioplasty (PTCA) was successfully performed in 257 of 304 patients (85%) greater than or equal to 5 years after their last bypass surgery. A lesion was successfully dilated in 496 of 566 vessels attempted (88%): 332/386 coronary arteries (86%) and 164/180 vein grafts (91%). Significant complications included: 8 (2.6%) mortalities, 4 (1.3%) emergency surgeries, 13 (4.3%) Q-wave myocardial infarctions, and 14 (4.6%) distal embolizations. Distal embolization occurred in 13/180 (7%) vein graft lesions dilated and usually resulted in a non-Q-wave infarction (4/13 distal embolizations). A second PTCA was performed on 89 (35%) patients: 44% of them had lesion recurrence; 20% a new lesion requiring dilatation; and 30% both recurrence and new lesion. Follow-up (mean 3.7 years) revealed 78% of patients having an improved anginal status, and 58% no angina. The cumulative probability of survival at 60 months was 88 +/- 3%. Angioplasty can be effectively employed in patients greater than or equal to 5 years remote from their last bypass surgery in native arteries or saphenous vein grafts with good procedural and long-term success. Vein graft age inherently does not appear to be a contraindication to angioplasty.

Percutaneous transluminal angioplasty of saphenous vein graft stenosis: long-term follow-up

Percutaneous transluminal angioplasty was used to treat 101 patients with saphenous vein bypass graft stenosis at a mean of 50.1 months (range 2 to 196) after coronary artery bypass surgery. The patients presented between March 1981 and April 1987. A total of 107 saphenous vein grafts were dilated at 117 sites. The primary success rate was 91.8%. The incidence of cardiac complications was 7.1%. There were no cardiac complications in 53 patients with grafts implanted less than 36 months before angioplasty (Group 1). The 48 patients with grafts implanted for greater than 36 months (Group 2) had a 12.5% incidence rate of myocardial infarction, a 4% incidence rate of emergent bypass surgery and a 4% incidence rate of death for an overall cardiac complication rate of 14.9% (p less than 0.01). Follow-up was obtained at a mean of 16.8 +/- 13.9 months (range 1 to 54) in 87 patients (97% of successful cases). Repeat coronary angiography was performed in 49 patients and revealed restenosis in 30 patients (61.2%), with no difference in recurrence rates for proximal, mid or distal graft sites. Clinical recurrence (defined as recurrence of symptoms, myocardial infarction, repeat angioplasty, surgery or death) was 33.1% for Group 1 patients and 64.1% for Group 2 patients (p less than 0.01). The complication and recurrence rates of saphenous vein graft angiography are significantly higher when performed for late (greater than 36 months) vein graft failure. All therapeutic options should be carefully examined before proceeding with angioplasty for saphenous vein graft stenosis in this type of patient.

Venospastic phenomena of saphenous vein bypass grafts: possible causes for unexplained postoperative recurrence of angina or early or late occlusion of vein bypass grafts

Angina recurred in a 54 year old white man after multivessel coronary artery bypass surgery. Fourteen months after operation the frequency and intensity of his mixed angina increased and cardiac stress testing was positive. Repeat cardiac catheterisation showed that all the bypass grafts were widely patent; however, spasms of a vein graft to right coronary artery system were clearly seen. Treatment with calcium blocking agents and long acting nitrates abolished the symptoms during 16 months of clinical follow up.

Percutaneous transluminal angioplasty in patients with prior myocardial revascularization surgery

Direct myocardial revascularization surgery using either the saphenous vein or internal mammary artery has become the definitive surgical treatment for coronary artery occlusive disease. Certain patients who have undergone these procedures, however, have recurrent myocardial ischemia due to progression of disease in unbypassed vessels, to obstruction in the arteries distal to the insertion of the bypass conduit, or to disease of the conduit itself. Balloon angioplasty may be used to relieve myocardial ischemia in these situations; however, initial studies suggested a low primary success rate coupled with excessive mortality and morbidity. Improvements in patient selection, equipment and technical expertise now allow angioplasty to be performed in this patient population with results comparable to that in the general coronary angioplasty population. Of the 3,016 angioplasty procedures performed between September 1980 and June 1987, 236 patients had previously undergone revascularization surgery. The primary success rate was 93% (390 of 419 stenoses successfully dilated). Overall, clinical restenosis was observed in 39%, including a 43% restenosis rate in patients undergoing only saphenous vein graft angioplasty. This did not differ appreciably from the restenosis rate in postbypass patients undergoing angioplasty of only native vessels (37%) or internal mammary arteries (42%). Emergency revascularization surgery was required in 7 of 236 patients (3%), each of whom had myocardial infarction. One of 236 patients (0.4%) died. Thus, angioplasty may be used to relieve recurrent myocardial ischemia in patients with prior direct myocardial revascularization procedures with a high initial success rate and acceptable risk. Early (less than 6 months) restenosis is not infrequent and remains the largest obstacle to a satisfactory clinical outcome.(ABSTRACT TRUNCATED AT 250 WORDS)

Haemoptysis caused by aneurysm of saphenous bypass graft to a coronary artery

In a 51-year-old man, coronary artery bypass surgery for severe angina pectoris was followed by protracted mediastinal infection. After recovery the patient had several haemoptyses. Angiography revealed aneurysm of a graft near its distal anastomosis. Upper left lobectomy and ligation of the graft were necessitated by bleeding from the aneurysm into a segmental bronchus. Angina pectoris recurred but was successfully treated with verapamil.

Exercise radionuclide assessment of left ventricular function before and after coronary bypass surgery

The effects of elective saphenous vein coronary artery bypass surgery on left ventricular ejection fraction were assessed by using exercise first-pass radionuclide angiography in 66 consecutive patients. All patients with left main coronary artery or concomitant valvular disease were eliminated from the study. Before surgery, 7 patients had normal postexercise left ventricular function (Group 1), 33 had normal resting left ventricular function with an abnormal response to exercise (Group 2), and 26 had an abnormal resting left ventricular ejection fraction with an abnormal response to exercise (Group 3). Following surgery, patients in all three groups had no change in mean resting left ventricular ejection fraction; however, patients in Groups 2 and 3 had significant improvement in mean postexercise left ventricular ejection fraction (p less than 0.0001 and p less than 0.0054 respectively), whereas patients in Group 1 did not. Previous studies reported improvement in postexercise ejection fraction in patients with reduced resting left ventricular function and with an ischemic response to exercise (Group 3). But this is the first study to confirm improvement in postexercise function in patients with normal resting function and an ischemic response to exercise (Group 2).

Principles of preparation of vein bypass grafts to maximize patency

Experience in cardiovascular and peripheral vascular surgery with saphenous vein bypass conduits is reviewed. It is clear that meticulous technique and graft preparation are crucial to short-term and long-term patency. The risk of early thrombosis is related to damage to the graft's native intima, graft flow, and coagulability of the patient's blood. Attention to atraumatic harvesting techniques and perfection of anastomoses are crucial to minimizing intimal damage. Graft inflow and outflow are fundamental principles. The use of vitamin K antagonists and platelet inhibitors may improve graft survival. Subacute occlusion is related to structural alterations in the grafts themselves. These include intimal hyperplasia and medial fibrosis as the grafts become "arterialized," valve fibrosis, aneurysmal dilatation, clamp stenosis, and suture stenosis. Long-term patency is threatened primarily by atherosclerosis in the graft itself. There is some evidence that care in vein harvesting and implantation as well as the use of anticoagulant agents affect the development of this complication. A technique for graft preparation is presented that is based on the experience of the authors in harvesting grafts for both cerebral and coronary bypass conduits.

Percutaneous transluminal angioplasty of stenotic coronary artery bypass grafts: 5 years' experience

In a 60 month period (January 1981 to December 1985), 82 patients (79% male with a mean age of 60 years) had 83 saphenous vein grafts and 5 internal mammary artery grafts with a total of 101 stenotic sites treated with percutaneous transluminal coronary angioplasty. The mean time between bypass surgery and angioplasty was 51.2 months. The procedure was technically successful in 85% of patients, 86% of grafts and 85% of the sites attempted. In these cases, the mean diameter stenosis was reduced from 77 +/- 14 to 27 +/- 20% (p less than 0.001), the mean pressure gradient from 49 +/- 16 to 7 +/- 6 mm Hg (p less than 0.001). Emergency coronary artery bypass graft surgery was necessary in one patient (1.2%) whereas myocardial infarction occurred in three patients (3.6%). There were no hospital deaths. Clinical follow-up was obtained in all 82 patients. Before angioplasty, 23% were in Canadian Cardiovascular Society functional class II, 60% in class III and 17% in class IV. With a mean clinical follow-up period of 21.4 +/- 2.3 months, 71% are in class I, 17% in class II and 12% in class III. There were two deaths, 3 months or more after angioplasty, one probably due to graft closure. So far, angiographic follow-up (at 7.9 +/- 2.1 months) has been available in 26 patients. Ten patients (with 10 grafts) exhibited graft restenosis; six of them have had second successful repeat angioplasty. Among the many variables analyzed, statistically significant predictors of success were a higher measured balloon/graft ratio (p less than 0.001), smaller diameter graft (p less than 0.001), and shorter lesion length (p less than 0.01). The only predictor of complication was diffuseness of disease in the graft (p less than 0.05). The statistically significant predictors of recurrence were the residual stenosis after the initial angioplasty (p less than 0.01) and the measured balloon/graft ratio (p less than 0.01). Angioplasty of coronary artery grafts appears to be a feasible and efficacious procedure with a low complication rate. The technique is a satisfactory alternative to repeat surgery in selected patients.

Angioplasty for aortocoronary bypass graft stenosis

During the period November 1979 to October 1984, 19 patients at our institution underwent balloon angioplasty of partial or complete obstruction of aortocoronary artery saphenous vein bypass grafts. The procedures were performed a mean of 38 months after a coronary bypass operation to relieve recurrent angina of at least class 2 in the Canadian Cardiovascular Association functional classification. Graft angioplasty was successful in 16 of the 19 patients, and the location of the lesion (in the origin, body, or distal insertion of the graft) did not seem to be an important factor in achieving a successful result. At a mean follow-up interval of 20 months (range, 1 to 40 months), 14 patients had symptomatic improvement. Two patients required late repeat operation and four had repeat angioplasty because of restenosis. Our experience supports the use of balloon angioplasty in selected patients with bypass graft stenosis, but restenosis remains a substantial problem.

Percutaneous transluminal coronary angioplasty after previous coronary artery bypass surgery

To improve symptomatic status and avoid repeat coronary artery bypass graft surgery (CABG), 115 lesions were approached for transluminal coronary angioplasty (PTCA) in 94 patients (82 men, 12 women) with angina pectoris and prior CABG at a mean of 60 months (range 4 to 192) after CABG. Fifteen patients were in Canadian Cardiovascular Society functional class I, 32 were in class II, 31 were in class III, and 16 were in class IV. Patients were 37 to 76 years old (mean 57). PTCA was successful (at least a 40% reduction in stenosis diameter and improvement in symptomatic status) in 83 patients (88%) and 103 (90%) lesions. Mean stenosis was reduced from 80 +/- 14% to 20 +/- 16% (mean +/- standard deviation) and mean pressure gradient from 41 +/- 7 mm Hg to 14 +/- 6 mm Hg. Seven patients had lesions that could not be crossed for technical reasons and these patients underwent non-emergency CABG. Four patients required emergency CABG after PTCA; 1 patient subsequently died and 2 survived acute myocardial infarction. One patient had a femoral artery laceration, which required surgical repair. At a mean follow-up of 8 +/- 4 months, 63 patients (76%) with initially successful results were free of angina or in improved condition. Of the remaining 20 patients, 18 consented to repeat coronary angiography. Four patients did not have restenosis. Of the 14 patients with documented restenosis, 5 underwent successful repeat PTCA, 5 had repeat CABG, and 4 were treated medically. Thus, when coronary anatomy is suitable, PTCA is an effective alternative to reoperation in symptomatic patients with prior CABG.

Competitive blood flow in the coronary circulation simulating progression of proximal coronary artery disease after saphenous vein bypass surgery

We report a case of competitive blood flow in the left coronary circulation after saphenous vein bypass grafting that resulted in the apparent progression of a proximal stenosis to total occlusion at coronary angiography. Repeat angiography with careful attention to catheter position and adequate injection of contrast agent demonstrated the actual anatomy and showed that there was no postoperative change in the native coronary circulation. The true incidence of progression of proximal coronary disease after saphenous vein bypass surgery is unknown, and reported figures may be falsely elevated because of unrecognized competitive flow patterns simulating obstruction.

Percutaneous transluminal coronary angioplasty in patients with prior coronary bypass surgery

To improve symptomatic status and avoid reoperation, 122 initial and 7 repeat percutaneous transluminal coronary angioplasty procedures were performed in 116 patients with disabling angina pectoris at a mean of 26.8 months (range 2 to 132) after coronary bypass surgery. Marked angiographic improvement (greater than 30% reduction in diameter stenosis) was obtained in 107 (88%) of the 122 initial procedures and in all 7 repetitions. Mean stenosis was reduced from 78 +/- 13% (mean +/- standard deviation) to 25 +/- 13% (p less than 0.0001) and mean pressure gradient from 49 +/- 15 to 11 +/- 8 mm Hg (p less than 0.0001). Complications were: emergency surgery (three patients), Q wave infarction (one patient), myocardial infarction by enzyme criteria only (four patients) and non-occluding coronary dissection (one patient). There were no neurologic or peripheral vascular complications and no early deaths. One late death occurred 14 months after an unsuccessful but uncomplicated angioplasty procedure. At a mean follow-up of 8.3 months, 88 patients (76%) were free of angina or in improved condition. In patients followed up for at least 6 months, evidence of restenosis occurred in 9 (53%) of 17 saphenous veins, 1 (50%) of 2 proximal graft anastomoses, 4 (18%) of 22 distal graft anastomoses and 5 (14%) of 37 native coronary arteries. When coronary anatomy is suitable, percutaneous transluminal angioplasty is an attractive alternative to reoperation in symptomatic patients with prior coronary bypass surgery.

Internal mammary artery versus saphenous vein graft. Comparative performance in patients with combined revascularisation

Thirty three patients with coronary artery disease undergoing combined myocardial revascularisation with internal mammary artery and saphenous vein grafts underwent angiographic studies up to 10 years after operation. Each patient had one internal mammary artery graft and one or more saphenous vein grafts. Eleven symptom-free patients, studies one month to five years (mean 1.9 years) after operation, had intact internal mammary artery and saphenous vein grafts in a good state of preservation. Of the six patients developing symptoms within the first year after surgery, three had evidence of poor flow in the internal mammary artery graft because of large side branches and the other three had stenosis or occlusion of the saphenous vein grafts. Sixteen patients developed symptoms after several years free of symptoms and were studied three to 10 years (mean six years) after operation. Of the 23 saphenous vein grafts in this group, 17 (74%) were either occluded or severely stenosed and six (26%) were in good condition. One internal mammary artery graft was occluded and the remaining 15 were in good condition. Saphenous vein graft failure was the predominant cause of late development of symptoms in patients with combined revascularisation. Long term performance of the internal mammary artery grafts is far superior to the saphenous vein grafts.

Transcatheter embolization of a leaking pseudoaneurysm of saphenous vein aortocoronary bypass graft

We present a case of successful transcatheter embolization of a leaking pseudoaneurysm of an autogenous saphenous vein aortocoronary graft that developed 9 years following bypass surgery.