John G. Pollock

Experimental and Clinical Experience with a Gelatin Impregnated Dacron Prosthesis

Laboratory and clinical evaluation of a knitted Dacron graft impregnated with gelatin to confer zero porosity is described. Graft performance was tested by standard methods for biodegradation of the sealant and in vitro thrombogenicity. The gelatin sealant was removed after seven to nine days and there was no platelet adhesion to Gelseal compared with unsealed Dacron. Animal experiments revealed normal macroscopic appearances in the graft and histological disappearance of the gelatin impregnate between five and ten days, allowing a cellular response similar to unsealed Dacron. The first 100 patients to have Gelseal aortic bifurcation graft implanted at Glasgow Royal Infirmary are described. The graft did not require preclotting. Blood transfusion was not necessary in 74% of patients. There is 100% patency at 21 months. A knitted Dacron graft sealed with gelatin is a safe, nonporous prosthesis at implantation.

Long-Term Survival in Patients Undergoing Resection of Abdominal Aortic Aneurysm

The long-term survival of patients undergoing abdominal aortic aneurysm surgery is presented. Three-hundred and thirty-eight patients who presented with elective, urgent, or emergency abdominal aortic aneurysms, have been followed retrospectively for five years. We found no statistical difference in the long-term survival in these three groups of patients. As expected patients who had successful operation survived better than patients who were not offered surgery because of their poor medical condition. Interestingly, advancing years, history of myocardial infarction or hypertension did not significantly influence long-term survival.

Sealed versus Unsealed Knitted Dacron Prostheses: a Comparison of the Acute Phase Protein Response

Twenty patients were randomized to receive either an untreated Dacron aortic bifurcation graft (n = 10), or a similar graft impregnated with gelatin (n = 10). Venous blood samples were taken preoperatively and at frequent intervals until five weeks after surgery. C-reactive protein (normal range less than 10 mg/l) and alpha l-acid glycoprotein (normal range 0.3-1.0 g/l) were measured. The peak mean value of C-reactive protein for the sealed group was 226.3 +/- 49.2 mg/l and 221.3 +/- 56.4 mg/l for the unsealed group. The corresponding values for alpha 1-acid glycoprotein were 1.49 +/- 0.25 g/l and 1.44 +/- 0.3 g/l. The C-reactive protein response returned more quickly to normal, with only two patients in each group having a slightly elevated response after four weeks, while the value for alpha l-acid glycoprotein remained elevated at five weeks for the same two patients in each group. There was no significant difference between the serum acute phase protein response in either group. This suggests that a knitted Dacron graft sealed with gelatin does not exaggerate the inflammatory response.

A Prospective Study of 100 Gelatin-Sealed Aortic Grafts

A gelatin-sealed knitted Dacron graft has been developed which has zero porosity at Implantation and does not require preclotting. Its patency rate up to 57 months and effectiveness at saving blood loss have been studied. Gelatin-sealed aortic grafts were implanted into 100 consecutive patients-77 men, 23 women. Surgery was performed for aneurysm in 36 patients (including four with rupture), intermittent claudication in 44, rest pain in 17, and gangrene in three, over an 18 month period. The patients were followed up prospectively for 57 months. Perioperative mortality was 1%. Cumulative primary graft patency was 99%. There was no measurable blood loss at implantation. Forty-seven patients required blood transfusion: mean volume transfused was 430 ml. There were no problems related to the sealant.

Ruptured Aortic Aneurysms: Postoperative Complications and Their Management

Postoperative complications in 92 patients undergoing repair of ruptured abdominal aortic aneurysms are reviewed. Renal failure and cardiac complications were fatal in 74% and 85% of the patients, respectively. Preoperative renal function at the time of presentation had no correlation with the development of renal failure. All but one patient in whom the left renal vein was divided developed renal failure postoperatively. There also was a preponderance of this complication in the patients needing suprarenal aortic control. Respiratory complications were seen in 29% of patients with 22% mortality. Peripheral emboli and ischemic colitis developed in 8% and 9% of the patients, respectively.

Percutaneous Angioplasty, Endothelial Markers, and Fibrin Turnover:

Purpose: A number of thrombotic mediators have been related to peripheral arterial disease in both epidemiological and pathological studies. Methods: We measured preoperative levels of fibrinogen, cross-linked fibrin degradation products (FDP), and the endothelial markers, von Willebrand factor (vWF), tissue plasminogen activator (tPA), and plasminogen activator inhibitor (PAD, in the venous blood of 43 claudicants undergoing percutaneous transluminal angioplasty (PTA). Samples were repeated 4 months later, and changes in the levels of thrombotic mediators were compared with ten controls undergoing angiography alone. Additional perilesional arterial samples were obtained from 11 of the patients. Results: Arterial sampling indicated that successful PTA led to an immediate fall in tPA levels and a rise in arterial vWF (p < 0.05), together with a trend toward a significant rise in cross-linked FDP levels. Only the increase in FDP following successful PTA (36 cases) (p < 0.05) was observed in 4-month postangioplasty venous samples, whereas all variables remained unchanged in cases of restenosis (4 patients) and in controls (all comparisons made by Wilcoxon matched pairs test). Conclusions: These findings suggest that successful PTA in patients with intermittent claudication results in acute endothelial disturbance and increased fibrin turnover at the site of angioplasty and in sustained increases in fibrin turnover (as reflected by FDP levels). The observation that this increase in fibrin turnover is absent in cases of restenosis within 4 months of PTA merits further study to determine whether increases in fibrin turnover are necessary to maintain patency following PTA.

Evaluation of Factors Influencing Survival in Ruptured Aortic Aneurysms

During the six year period ending in December 1986, 103 patients with ruptured abdominal aneurysms presented to the unit. Ninety-two patients underwent surgery with a mortality of 39%. There was an increase in mortality with preoperative risk factors, extent of surgery, prolonged stay in ICU, complications and amount of blood transfused. However, only the latter was statistically significant. Age, the distance traveled by the patient before arrival at the hospital, systolic blood pressure on presentation and duration of operation did not affect the mortality.

Monoclonal antibody immunoassay in the study of thrombogenicity of preclotted and gelatin-impregnated aortic prostheses.

The Dimertest Enzyme Immunoassay has been used to compare the degree of thrombogenicity of the standard knitted Dacron prosthesis (n = 10) and the gelatin-impregnated Dacron prosthesis (n = 10) after infrarenal aortic reconstruction. After surgery there was a similar rise in cross-linked fibrin degradation products with both types of prostheses. Although on the third day the D-Dimer level in the gelatin-impregnated prosthesis was lower, there was no significant difference in the D-Dimer level at six weeks. This suggests that the potential risk of thrombogenicity in the gelatin-impregnated prosthesis is similar to the standard preclotted type.

Book Review: Endovascular Grafting TechniquesEndovascular Grafting Techniques Editors: ParodiJuan C., MD VeithFrank J., MD MarinMichael L., MD Williams and Wilkins, Baltimore, 1999ISBN 0-0683-30209-4,

This is a beautifully bound hardback book on endoluminal grafting predominantly for aortic aneurysm. In the beginning, the editors predict that 45% to 65% of major vascular operations could be replaced by endovascular techniques in the near future. The subsequent 17 chapters, each by well-known authors giving their experiences with endografting, go far in persuading the reader that this prediction is accurate. Unfortunately, one drawback in producing a book with such a quality finish is the difficulty that the editors have in keeping the text current in a field where developments happen so quickly. For example, there are only 8 references beyond 1997, and noticeably absent are investigators experienced with the more modern devices, such as the AneuRx, Endologix, and newer endoluminal grafts for peripheral arteries. Indeed, some techniques in the text describe homemade devices, which are no longer commonly used. One bonus of this book is that most of the authors describe their own principles of endoluminal grafting. Another is the account by Drs. Parodi and Schönholz of their experience with the original endoluminal graft procedure for abdominal aortic aneurysm. Early chapters introduce the concept of endoluminal grafting, preoperative assessment, and imaging. Results with a variety of early devices, including the EVT, Vanguard, Chuter, and Cook systems, are provided from US and European investigators. Notable is a chapter by the Sydney (Australia) group that gives a much larger experience of endoluminal aortic grafting; it is excellent and provides some comparison with open repair. There are also well-done chapters on endoluminal grafting for thoracic aneurysm, vascular injury, and occlusive aortoiliac and femoropopliteal disease. However, up-to-date data are lacking. The reviewers praise this book for its quality and finish but are compelled to point out to the prospective reader that some portions of the text are already dated.

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This is a beautifully bound hardback book on endoluminal grafting predominantly for aortic aneurysm. In the beginning, the editors predict that 45% to 65% of major vascular operations could be replaced by endovascular techniques in the near future. The subsequent 17 chapters, each by well-known authors giving their experiences with endografting, go far in persuading the reader that this prediction is accurate. Unfortunately, one drawback in producing a book with such a quality finish is the difficulty that the editors have in keeping the text current in a field where developments happen so quickly. For example, there are only 8 references beyond 1997, and noticeably absent are investigators experienced with the more modern devices, such as the AneuRx, Endologix, and newer endoluminal grafts for peripheral arteries. Indeed, some techniques in the text describe homemade devices, which are no longer commonly used. One bonus of this book is that most of the authors describe their own principles of endoluminal grafting. Another is the account by Drs. Parodi and Schönholz of their experience with the original endoluminal graft procedure for abdominal aortic aneurysm. Early chapters introduce the concept of endoluminal grafting, preoperative assessment, and imaging. Results with a variety of early devices, including the EVT, Vanguard, Chuter, and Cook systems, are provided from US and European investigators. Notable is a chapter by the Sydney (Australia) group that gives a much larger experience of endoluminal aortic grafting; it is excellent and provides some comparison with open repair. There are also well-done chapters on endoluminal grafting for thoracic aneurysm, vascular injury, and occlusive aortoiliac and femoropopliteal disease. However, up-to-date data are lacking. The reviewers praise this book for its quality and finish but are compelled to point out to the prospective reader that some portions of the text are already dated.