Microscopic analysis of saphenous veins used for aortocoronary bypass

The Authors describe a study performed on a sample of 88 saphenous veins used as aorto-coronary bypass grafts. The patients underwent surgery in the Department of Cardiovascular Surgery of Ancona from Jan. 1981 to Dec. 1984. The morphological analysis (light and electron microscope) was conducted with a comparative method between two surgical techniques (ST). The first refers (Group I) to 1981-82, the second (Group II) to 1983-84. In Group I the veins were taken with a conventional surgical technique. In Group II the ST was performed using an atraumatic procedure, topic vasodilators, distension of the vein with autologous blood and driving pressure less than 150 mmHg, and storage of the vein in blood at room temperature. The results show that in Group II there is better preservation of the endothelial venous layer. The distending pressure of the venous graft (less than 150 mmHg) and prevention of venous spasm were statistically relevant (p less than 0.05). The AA. conclude that vein graft damage during surgery can be avoided by means of the following procedures: dissection of the vein with atraumatic technique; prevention of venous spasm with topic vasodilators; distension of the vein at pressure less than 150 mmHg.     

Changes in saphenous veins used as aortocoronary bypass grafts.

This report describes morphologic changes in saphenous veins used as aortocoronary bypass conduits, and discusses the relative contribution of various factors to these changes. The three primary changes are: (1) medial fibrous replacement, (2) adventitial fibrous proliferation, and (3) intimal fibrous proliferation. Medial fibrous replacement is caused by vein wall ischemia with loss of smooth muscle cells; adventitial fibrous proliferation is the result of organization of fibrin deposits and repair of ischemic injury; and intimal fibrous proliferation results from some stimulus, probably fibrin deposition on injured intima, which causes stimulation of smooth muscle cells to become fibroblasts or "myointimal cells". Although all grafts show some changes, the degree and severity of these three changes is variable along the length of the grafts and among separate grafts in the same patient.     

Morphologic observations after percutaneous transluminal balloon angioplasty of early and late aortocoronary saphenous vein bypass grafts

Clinical and morphologic observations from two patients undergoing percutaneous transluminal angioplasty of stenotic aortocoronary saphenous vein bypass grafts early (3 months) and late (56 months) after graft insertion are described. Each patient had one or more clinically successful graft dilations resulting in an angiographic increase in luminal diameter and a decrease in mean trans-stenotic gradient, and each had restenosis of the graft at the site of previous angioplasty within 2 months of dilation. Both operatively excised grafts had diffuse but variable amounts of intimal fibrous thickening and severe narrowing at the previous angioplasty site. The early graft had no evidence of dilation injury, and the intimal thickening consisted solely of fibrocollagenous tissue free of calcific deposits. In contrast, the late graft had a healing intimal dissection at the angioplasty site, and the intimal thickening consisted of atherosclerotic plaque with calcific deposits. Angiographic and morphologic correlations suggest that the mechanism of saphenous vein angioplasty early (less than or equal to 1 year) after insertion is by graft "stretching," while late (greater than 1 year) after insertion it is by atherosclerotic plaque "fracture" similar to that observed in atherosclerotic coronary arteries subjected to angioplasty procedures.     

Percutaneous transluminal angioplasty of stenosed aortocoronary bypass grafts

During the period between October 1980 and December 1982, percutaneous transluminal angioplasty of stenosed aortocoronary bypass grafts was attempted 44 times in 31 patients who had developed disabling angina pectoris four months to seven years after coronary bypass surgery. The primary success rate was 93%. Two (4.5%) patients developed myocardial infarction related to the procedure. No emergency aortocoronary bypass surgery was required and there was no mortality. Although the primary success rate was high, the incidence of recurrence after one or more angioplasties was 50%. Despite this recurrence rate the condition of 10 of the first 16 (62%) patients was clinically improved after a mean follow up of 26 months.     

A possible application of percutaneous transluminal angioplasty: remodelling of an occluded aortocoronary bypass

The authors report the case of a 53 year old patient who had undergone triple coronary bypass surgery for unstable angina. Recurrence of chest pain 4 months after surgery led to control coronary angiography which showed severe stenosis of the proximal and distal parts of the aorto-right coronary graft. Endoluminal dilatation was performed a few days later but, during angiography, complete occlusion of the graft was observed. This was repermeabilised without difficulty and a "remodelling" of the graft was carried out. The outcome was favourable with the complete regression of symptoms. The following alternatives to surgery are discussed: in cases of thrombosis which usually occur in the month following surgery, fibrinolysis may be attempted with a high success rate but a significant risk of haemo-pericardium: in cases of fibrous proliferation of the intima leading to stenosis or occlusion, endoluminal dilatation seems to be the procedure of choice, but this must always be carried out under surgical cover.     

Percutaneous angioplasty of totally occluded saphenous aortocoronary bypass graft

We describe a case of successful percutaneous transluminal angioplasty of a totally occluded saphenous aortocoronary bypass graft with improvement of clinical symptoms and disappearance of collaterals.     

Percutaneous transluminal angioplasty of stenosed aortocoronary bypass grafts.

During the period between October 1980 and December 1982, percutaneous transluminal angioplasty of stenosed aortocoronary bypass grafts was attempted 44 times in 31 patients who had developed disabling angina pectoris four months to seven years after coronary bypass surgery. The primary success rate was 93%. Two (4.5%) patients developed myocardial infarction related to the procedure. No emergency aortocoronary bypass surgery was required and there was no mortality. Although the primary success rate was high, the incidence of recurrence after one or more angioplasties was 50%. Despite this recurrence rate the condition of 10 of the first 16 (62%) patients was clinically improved after a mean follow up of 26 months.     

Intravascular ultrasonic differences between aorto-ostial and shaft narrowing in saphenous veins used as aortocoronary bypass grafts

Previous studies have reported differences in interventional complication rates that depend on saphenous vein graft (SVG) lesion location. However, little is known about morphologic differences between lesions in different SVG locations. We evaluated preintervention intravascular ultrasound (IVUS) images of 75 de novo SVG lesions (aorto-ostial, n = 15; shaft, n = 60) in 63 patients. IVUS data were measured at the minimal lumen area and at 2 proximal and 2 distal references. Positive remodeling was defined as a lesion site SVG area that was larger than the average of the 2 distal references. Shaft lesions more often contained soft plaque (60.0% vs 26.7%, p = 0.02). Minimal lumen areas were identical (4.5 +/- 2.9 vs 4.3 +/- 1.5 mm2, p = 0.3); however, plaque burden at the minimal lumen area was greater in shaft locations (79.3 +/- 9.4% vs 72.1 +/- 9.2%, p = 0.01). The frequency of positive remodeling in shaft versus aorto-ostial lesions was 70.2% versus 26.7% (p = 0.002). SVG shaft lesions have more soft plaque and larger plaque burdens and undergo positive remodeling more frequently than SVG aorto-ostial lesions. These IVUS differences may account for some of the location-specific differences in interventional complications.     

Renal arterial pathology after percutaneous transluminal angioplasty

Percutaneous transluminal angioplasty (PTA) has been shown to cause cracking of the intimo and atherosclerotic plaque in the renal arteries of two cases, who died from incidental causes about a week after the procedure. In addition, movement or redistribution of atheromatous gruel was seen into the cracks and dissections at the intima-medial junction and media. Thus, enlargement of the lumen by redistribution of the lipid mass by 'warm flow' may be an important beneficial result of angioplasty. One case also showed severe fragmentation of medial elastic fibres at the orifice, with rupture of the internal elastic membrane.     

Clinical experience of percutaneous transluminal coronary angioplasty

PTCA (percutaneous transluminal coronary angioplasty) was performed on 44 patients with angina pectoris during the 18-month period from April 10, 1981 to September 30, 1982. It was successful in 36 of the 44 patients (82%), resulting in a subsidence of the symptoms and a considerable increase in exercise tolerance. Successful dilatations were achieved in 30 of 35 left anterior descending arteries (86%) and 7 of 11 right coronary arteries (64%). Five patients had complications: myocardial infarction in 2, unstable angina pectoris in 1, and dissection of the coronary artery in 2. One of these patients underwent an urgent A-C bypass operation. The patients were followed up for 0.5 to 18 months (average: 7.4 +/- 0.9 months). Stenosis recurred in 6 patients (16.7%), but repeat PTCA disclosed successful dilatations of stenotic lesions in 3 patients. No deaths occurred throughout the study period including the follow-up period. Our experience suggests that PTCA is of use in the treatment of certain groups of angina pectoris patients if case selection is appropriate.     

Surgical experience following percutaneous transluminal coronary angioplasty

Percutaneous transluminal coronary angioplasty (PTCA) was attempted in 600 patients, 97 of which were considered unsuccessful. Review of our surgical experience in a large series of these procedures helps to confirm some facts regarding the unique interaction between these two modalities of myocardial revascularization. Serious complications are still relatively common, even when PTCA is performed in centers with broad experience. While emergency operation is not required in all major complications, about 7% of patients need immediate surgical intervention, which is usually performed on unstable patients, and thus associated with increased morbidity and mortality. The combined incidence of major complications, such as coronary dissection, occlusion, and spasms, still approaches 20% of attempts. In contrast to other studies, surgical mortality and morbidity do not appear to be higher in our series of operations on patients with complicated PTCA than in coronary bypass operations in general. This fact may attest to our practice of alerting all surgical services in anticipation of problems. Our short complication-to-operation completion time, averaging 123 minutes, may be partially responsible for the good results. We conclude that standby open-heart services for PTCA are warranted in most hospitals; however, it should not be performed in hospitals without surgeons who are experienced in the practice of open-heart surgery.     

Alteration of "jetlike" laminar flow after percutaneous transluminal angioplasty of saphenous vein bypass graft stenosis

Coronary angiography in a patient with a stenosis in a saphenous vein graft 7 years after surgical anastomosis demonstrated a striking angiographic "jetlike" laminar flow pattern. Both the severe stenosis and "jet" appearance were markedly altered after percutaneous transluminal coronary angioplasty (PTCA). We believe this unusual angiographic finding represents visual evidence of a pressure gradient and severe disturbance of laminar flow across the lesion, which was improved after PTCA.     

Results of emergency bypass operation following percutaneous transluminal coronary angioplasty

Between 1980 and 1988, percutaneous transluminal coronary angioplasty (PTCA) was performed in 1,514 patients. Fifty-five patients (3.6%) underwent emergency coronary bypass surgery because of an acute occlusion of the vessel or a dissection with sustained angina and signs of ischemia on the electrocardiogram. Twenty-five of these 55 patients had a myocardial infarction and 5 patients died, 3 perioperatively, 2 after hospital discharge. The degree of stenosis of the dilated vessel significantly influenced the incidence of infarction, while left ventricular ejection fraction prior to PTCA significantly influenced mortality. Patients who underwent surgery with an occluded vessel experienced myocardial infarction significantly more often (87%) than patients with a patent vessel (24%). The incidence of infarction was 27% when reperfusion of the vessel occluded during PTCA was achieved with a reperfusion catheter, repeated PTCA or intracoronary lysis. The patients' age, presence of unstable angina, left ventricular ejection fraction prior to PTCA, the dilated vessel, the extent of coronary artery disease, collateralization of the dilated vessel, and the time between the onset of the event necessitating bypass surgery and the beginning of extracorporeal circulation were found to have no influence on the incidence of infarction. Patients who died had a significantly lower ejection fraction before PTCA than survivors and all patients who died had experienced a large perioperative myocardial infarction.     

Emergent saphenous vein graft stenting for acute occlusion during percutaneous transluminal coronary angioplasty

This report describes the initial use in the United States of emergency intravascular stenting for the treatment of acute coronary occlusion complicating elective saphenous vein graft angioplasty. This case adds further support to the role of the balloon expandable stent as an effective "bail out" device for failed angioplasty.