Patch Graft Angioplasty Research Articles

A New Clamp for Patch Graft Angioplasty of Coarctation of the Aorta

A new clamp controls the great vessels in the region of aortic coarctation, allowing unhampered access to the aortotomy in patch graft angioplasty.

Surgical technique for creation of an arteriovenous fistula using a looped bovine graft.

We have used bovine grafts in a looped configuration in the forearn in 150 patients for chronic hemodialysis and have evolved a simple technique for their successful implantation. The critical technical points include: 1) use of large-diameter long grafts (7.0-8.0 mm diameter; 34-40 cm in length); maintenance of the heterograft in a distended and pulsating state throughout the procedure to prevent distortion and twisting; 3) creation of a wide smooth-looped tunnel with Bakes dilators; and 4) anastomosis to the largest avialable antecubital vein. Thirteen cases of late graft occlusion (3-36) months) have been found to be produced by a localized obstructive lesion just distal to the venous anastomosis. These grafts were easily restored to a functional status by thrombectomy and patch graft angioplasty of the stenotic segment. The looped graft technique is not applicable to all patients requiring hemodialysis but it is especially helpful when distal vessels have been obliterated by previous procedures or when home-dialysis is planned. This surgical technique should be among the alternatives considered by surgeons concerned with problems of vascular access in patients with chronic renal failure.

Coronary gas endarterectomy

ince the development of selective coronary angiography, the direct surgical repair of obstructive coronary disease has attracted widespread interest. Direct intervention employing standard endarterectomy and patch graft angioplasty for localized lesions achieved only limited application because of either excessive mortality rates or failure to regularly achieve long term patency of the operated vessels. Consequently, these procedures were abandoned in favor of indirect revascularization with internal mammary artery implantation. While the implants have been successfully performed and subsequently proved to be functional angiographically, a desire to perform successful direct surgery continued to attract experimental and clinical interest. In 1967 the first use of gas endarterectomy in coronary arteries was reported. It was felt at that time that certain technical advantages of this new approach would lead to a more favorable and widespread application of the endarterectomy principle in coronary disease. A careful analysis of the earlier attempts at mechanical endarterectomy revealed the following important considerations to be responsible for the unsatisfactory results previously obtained : 1. Preoperative assessment of the location and extent of coronary lesions was impaired due to the unavailability of suitable coronary radiography. 2. Incomplete “cleanout” of a diffusely diseased vessel occurred. 3. Technical difficulties related to closure of the arteriotomy site were present. 4. Failure to reopen side branches (“snow plow” effect) with consequent impaired runoff occurred. 5. Application of endarterectomy to the left coronary tree with its attendant high mortality was a factor. 6. A lack of appreciation of the ability of the dominant right coronary artery to collateralize the left coronary tree was also responsible. With the problem of accurate coronary angiography solved, and having overcome the technical difficulties related to endarterectomy described above, gas endarterectomy has now become a part of the surgical armamentarium available to treat obstructive coronary disease. In the past three years it has been applied in more than 75 cases in five medical centers in this country. Complete removal of disease from a dominant right coronary artery via one or two arteriotomies is readily accomplished. Less than 60 min. of cardiopulmonary bypass time has been usual. Three to 6 inch multibranched casts of the right coronary artery from coronary ostia to posterior descending

Surgical Considerations in Extracranial Occlusive Lesions

The criteria for selection of a patient with symptomatic cerebral arterial insufficiency as a candidate for surgical therapy differ in various institutes. For this reason it is difficult to interpret the data on incidence provided by large statistics. The symptomatology differs according to the main type of the occlusion: The carotid type with recurrent dizziness or instability, contralateral numbness or even paralysis of one limb, transient ipsilateral blurring of vision, and deterioration of the ability to do mental work; the vertebrobasilar type with transient periods of vertigo, weakness of the limbs, visual disturbances (of both eyes), and cerebellar ataxia. In the past decade major surgical principles in reconstructive arterial surgery have been stabilized to a large extent. The most favored methods are: Endarterectomy eventually combined with a patch graft angioplasty. This procedure is specifically suitable for lesions of the carotid bifurcation and in the internal carotid and vertebral artery area. Resection of the diseased segment and insertion of a venous or heteroplastic prosthesis bypass procedures are employed in lesions of branches of the aortic arch, especially if there are multiple segmental lesions. The application of this technique depends on the extent and location of the lesion and the condition of the patient (intraversus extrathoracic approach). The best candidates for operation are patients with intermittent attacks of cerebral arterial insufficiency who are neurologically intact. Second best are the patients with progressive neurologic deficits and those with a stable neurologic deficit.

Lesions of the renal artery: Surgical technic and results

1. 1. An analysis is presented of our experience during the past five years with 225 hypertensive patients having occlusive lesions of the renal arteries in whom some type of vascular surgical procedure designed to restore normal circulation to the kidneys was performed. 2. 2. Atherosclerosis was the most common etiologic basis for the occlusive process, accounting for 83 per cent of the patients. The next most common type of occlusive lesion was fibromuscular hyperplasia, occurring in 13 per cent of the patients. In the remaining patients the lesions were the result of aneurysms of the renal arteries and an unusual form of coarctation of the abdominal aorta in the region of the origin of the renal arteries. 3. 3. The occlusive process involved the main renal arteries in 90 per cent and an accessory renal artery in 10 per cent of the patients. Bilateral involvement was present in 30 per cent. 4. 4. Associated diseases of the abdominal aorta in the form of aneurysms or occlusive lesions requiring simultaneous surgical treatment were present in 30 per cent of these patients. 5. 5. The age distribution of these patients ranged from eight to seventy-two years, with 82 per cent being in the third through seventh decades of life. The male sex predominated in a ratio of about 2:1. In the group with fibro-muscular hyperplasia, however, the female sex predominated in a ratio of about 5:1. 6. 6. The duration of hypertension was less than two years in 42 per cent and more than five years in 33 per cent of the patients. The onset of hypertension was symptomatic in 60 per cent. 7. 7. Although various screening methods were employed in the study of these patients and found to be useful, the most reliable definitive diagnostic procedure has been found to be arteriography. In this connection determination of a pressure gradient across the lesion by intra-arterial blood pressure measurements during operation has been found to be particularly significant. 8. 8. Several surgical principles with certain technical variations designed to overcome the occlusive process in the renal arteries and to restore normal circulation to the kidneys may be employed, depending upon the type, location and extent of the lesion and upon associated diseases of the abdominal aorta. Among these the three most commonly employed are endarterectomy, patch graft angioplasty and the bypass procedure. 9. 9. The results of operation in this series have been quite gratifying. Followup studies ranging up to five years, with an average of about two years, have been made on all patients. Blood pressure has been restored to normal in 81 per cent of the patients. In 8 per cent a significant lowering of diastolic blood pressure. The total mortality, including both operative and subsequent deaths, was 5.8 per cent.

Experience with 200 Renal Artery Reconstructive Procedures for Hypertension or Renal Failure

Renovascular hypertension is the most common form of reversible hypertension. An analysis of 200 renal artery reconstructive procedures identified atherosclerosis as the arteriopathic lesion in 83 per cent of cases and fibromuscular hyperplasia in 13 per cent of cases. Bilateral renovascular disease was found in 31 per cent of cases. Renal arteriography is the most significant factor in the diagnostic evaluation of the hypertensive subject. Bypass graft and patch-graft angioplasty were the most commonly employed principles of renal artery reconstruction in this series. The occlusive process in the renal artery produced a pressure gradient exceeding 25 mm. Hg in 76 per cent of cases. The average period of observation following operation in these 200 patients was 1.6 years, ranging between 3 months and 5 years. Eighty per cent of patients are now normotensive. The primary goal of operation in 12 patients was reversal of renal failure due to severe bilateral renal artery occlusive disease. Disappearance of azotemia with improved renal function followed revascularization in 11 of 12 patients.

Treatment of hypertension associated with renal arterial occlusive disease

Renal artery stenosis is a common cause of diastolic hypertension. Recent development of arterial reconstructive technics provides the opportunity to cure most patients with renovascular hypertension and to salvage the involved kidney or kidneys. Resectional therapy provides a second type of treatment when definitive arterial reconstruction is impossible. Patch graft angioplasty and renal artery bypass are the two most satisfactory technical means of renal revascularization. Selection of patients with renal artery stenosis for revascularization is primarily a matter of exclusion. Specific contraindications include cerebrovascular insufficiency and coronary artery disease. Eighty per cent of 140 patients having renal revascularization procedures were cured of hypertension.

Renovascular hypertension: Experience with renal artery reconstruction in 115 patients

Renovascular hypertension as produced by narrowing of one or both renal arteries is the most common surgically curable form of unremitting high blood pressure. Frequently, renal artery constriction is produced by atherosclerosis, usually localized in the proximal arterial segment. Other forms of renal artery narrowing include fibromuscular intimal and medial hyperplasia, as commonly observed in young patients, and aneurysms of the renal artery. Selection of hypertensive patients for renovascular study or operative treatment is fundamentally a matter of exclusion. Subjects with serious cerebrovascular insufficiency or coronary artery disease make poor candidates for surgical reduction of arterial pressure. Renal arteriography is the cardinal feature in the diagnostic study of patients with severe hypertension. Selection of technic for renal artery reconstruction depends upon varying anatomic and pathologic considerations. In this surgical series of 115 hypertensive patients renal artery bypass and patch graft angioplasty were the methods of renal revascularization most frequently used. Blood pressure following operation ultimately became normal in 80 per cent of patients, and significant improvement was observed in an additional 8 per cent.