A prospective study of 100 gelatin-sealed aortic grafts

Improved outcomes with an implantable left ventricular assist system: a multicenter study

BACKGROUND

Cumulative experience with the Novacor wearable electric left ventricular assist system (LVAS) now exceeds 850 recipients. The pump inflow conduit (IFC) has been implicated in embolic complications.

METHODS

Clinical outcomes were compared for two IFC designs in a retrospective, nonrandomized, multicenter study. The original IFC (woven, unsupported, crimped polyester: control group) and an alternative IFC (knitted, gelatin-sealed, integrally supported, uncrimped polyester: test group) were utilized upon availability in North American and European centers. Differences in cerebral embolism to 180 days postimplant were analyzed.

RESULTS

Four hundred ninety patients implanted between August 1996 and August 1999, were studied. Two hundred eighty-eight received the control IFC and 202 received the test IFC. The groups (control, test) were well matched for age (48, 49 years), etiology (idiopathic 53%[152 of 288], 55% [112 of 202]; ischemic 34% [97 of 288], 33% [66 of 202]) and mean observation time (97, 91 days). The incidence of embolic cerebrovascular accidents (CVA) was 21% (60 of 288) in the control and 12% (24 of 202) in the test group (p = 0.010). Independent risk factors for embolic CVA were found to be preimplant acute myocardial infarction (odds ratio 4.3), age above 50 years (odds ratio 2.1), and ischemic etiology (odds ratio 1.7). There was no difference in survival between the groups (71% [205 of 288], 68% [137 of 202]).

CONCLUSIONS

The alternative (test) IFC has significantly reduced the incidence of embolic CVA. This improvement is likely due to increased resistance to deformation at implant, improved neointimal adhesion, and more favorable blood flow characteristics within the conduit.

Impregnated polyester arterial prostheses: performance and prospects

Impregnated polyester arterial prostheses have gained wide acceptance by most vascular surgery teams, probably because these prostheses are easy to use, without any preclotting. We offer here a synthesis of the main studies that have appraised the experimental and clinical performance of these prostheses, and we delineate their major prospects.

Albumin-impregnated prosthetic graft for infrarenal aortic replacement: effects on the incidence and volume of perioperative blood transfusion

We retrospectively reviewed 290 cases in which an albumin-impregnated polyester prosthetic graft was used for surgical management of aortic bifurcation disease between November 1987 and December 1990. The purpose of this review was to determine the incidence and volume of blood transfusion and to evaluate the rate of patency and the incidence of infection achieved using this type of prosthesis. The indication for surgery was abdominal aortic aneurysm (AAA) in 218 cases (190 elective procedures and 28 emergency procedures) and occlusive disease of the aortic bifurcation (ODAB) in 72 cases. Mean follow-up was 25.5 +/- 13.4 months (range: 1 and 50 months). The incidence of blood transfusion for elective AAA and ODAB surgery was 30.2% and 32.3% intraoperatively, 21.3% and 12.9% postoperatively, and 40.4% and 42.6% overall. The mean number of red cell packs transfused for elective AAA and ODAB surgery was respectively 1 and 0.8 intraoperatively, 0.4 and 0.6 postoperatively, and 1.4 and 1 overall. No immediate or late graft infection prosthesis was observed in any patient in this series. Primary and secondary patency was 95.5% and 97.5% at 6 months with no graft thrombosis during further follow-up. The fact that use of an impregnated graft in management of aortic bifurcation disease was accompanied by a high incidence and volume of blood transfusion suggests that these grafts do not reduce perioperative blood loss. Use of an impregnated prosthesis had no effect on the rate of patency and the incidence infection.

Clinical, biochemical, and rheologic factors affecting the outcome of infrainguinal bypass grafting

PURPOSE

The purpose of this study was to determine the effects of patient characteristics, blood rheology, and plasma biochemistry on the outcome of infrainguinal bypass grafting.

METHODS

Blood rheology, plasma fibrinogen, cross-linked fibrin degradation products, von Willebrand factor (vWf) and other endothelial products, and clinical variables including smoking markers were determined before surgery in patients with 184 consecutive infrainguinal bypass grafts (90 vein, 94 synthetic grafts).

RESULTS

Fifty (27%) graft occlusions and 17 (9%) deaths occurred within 1 year of surgery. On univariate analysis a poor outcome was associated with elevated preoperative plasma fibrinogen, fibrin degradation products, vWf, and platelet levels, reduced hemoglobin and systolic ankle pressure, a below-knee anastomosis, a decrease in patent calf vessels, and the presence of tissue necrosis (all p < 0.001). On multivariate analysis increased preoperative vWf levels were predictive of poor postoperative outcome (relative hazard for upper quartile versus lower quartile = 1.82), as were a low systolic ankle pressure (relative hazard = 2.51), presence of tissue necrosis (relative hazard = 2.73), and female sex (relative hazard = 1.9). None of the other variables studied was related to outcome. With a preoperative risk score derived from the results, graft patency rates within 3 months of surgery fell to less than 25% with risk scores in the upper quartile.

CONCLUSIONS

Preoperative measurement of plasma vWf may enable more accurate prediction of the outcome of infrainguinal revascularization and when combined with other variables could assist in patient selection for these procedures. The association of vWf with graft occlusion supports a role for endothelial disturbance in graft occlusion.

Albumin-impregnated polyester vascular prosthesis for abdominal aortic surgery: an improvement?

AIM

To compare the peroperative blood loss and the postoperative systemic inflammatory reaction in patients receiving either a Vasculour II Albumin pre-impregnated prosthesis (VA group, n = 32) or a preclotted Vasculour II prosthesis (V group, n = 33) for elective surgery of the abdominal aorta.

SETTING

University Hospital.

DESIGN

Prospective, randomised study.

METHODS

Peroperative blood loss was measured over two different periods: Phase I from the beginning of the operation to the completion of the proximal anastomosis, when blood loss cannot be related to the model of prosthesis implanted and phase II after the completion of the proximal anastomosis to the end of the operation. Postoperative blood loss was evaluated by the determination of the retroperitoneal drainage volume over a period of 2 days immediately following the operation. The presence of periprosthetic fluid was measured with echography at days 4, 9, 30 and 60. The postoperative systemic inflammatory reaction was evaluated by measuring the sedimentation rate and the C reactive protein levels daily from day 1 to day 9, and at days 14, 21, 28, 45, and 60, and by measuring the body temperature daily from day 1 to day 9.

RESULTS

No significant differences of peroperative blood loss were observed. The same proportion of patients (35%) in both groups received homologous transfusion. The mean number of units of homologous blood transfused per patient was respectively 0.77 and 0.91 for the VA and the V group. The retroperitoneal drainage volume and the percentage of patients with periprosthetic fluid did not differ significantly. No significant differences in systemic postoperative inflammatory reaction were observed.

CONCLUSION

There were no benefits in using albumin-impregnated prosthesis as opposed to preclotted prosthesis in terms of peroperative and postoperative blood loss, or by looking at the incidence of homologous blood transfusion. However, the glutaraldehyde cross-linked albumin did not induce any systemic inflammatory reaction.

Albumin-coated vascular prostheses: A five-year follow-up

In June 1989, we set out to implant 200 albumin-coated aortic bifurcation grafts and to track the patients for a period of 5 years to determine whether coating the prosthesis with albumin affected the patency or the incidence of complication. Two hundred and one prostheses were implanted between June 1989 and July 1991. The primary and secondary patency at 5 years was 95% and 98%, respectively. No relation between gender and patency or between the state of the runoff and patency was found, but there was a statistically significant relation between age and patency (p = 0.00). Graft infection was recorded in three patients (1.5%). There were no instances of bleeding through the graft at the time of implantation. The mean intra- and postoperative blood requirement was 2 units. There have been no incidences of false aneurysm in the groin. We conclude that there are no disadvantages of coating the prosthesis with albumin, and a trial of coated versus uncoated prostheses would be impractical.

Inflammatory reactions after vascular prosthesis implantation: a comparison of gelatin-sealed and unsealed Dacron prostheses

Despite widespread use of the gelatin-sealed knitted Dacron prosthesis (GDP) in clinical practice owing to its zero porosity, the biological impacts of this graft are still controversial. We conducted a randomized controlled study on 50 patients undergoing abdominal aortic aneurysm repair to evaluate the inflammatory reaction to GDP (n = 25) and unsealed knitted Dacron prostheses (UDP, n = 25). There were no significant differences in the mean age, size of the aneurysm, operative time, blood loss, or transfusion requirements between the GDP and UDP groups. During the first 7 postoperative days (PODs), slight fever and leukocytosis were noticed in both groups. Significant differences in maximum body temperature, leukocyte count, and plasma C-reactive protein concentration were observed between the GDP and UDP groups on POD 14:37.2 +/- 0.5 degrees C vs 36.9 +/- 0.3 degrees C (P = 0.019), 8,151 +/- 1,788/microliters vs 6,914 +/- 1,501/microliters (P = 0.015), and 32.6 +/- 27.5 mg/l vs 19.0 +/- 15.8 mg/l (P = 0.048), respectively. By POD 21, however, there were no detectable differences in these variables. Thus, we concluded that GDP caused an inflammatory reaction in the 2nd week after implantation, but ultimately there were no significant differences from UDP by the 3rd week.

Transfusion and surgery

In this survey of transfusion in surgery, we have attempted to provide the surgeon with an understanding of the problems associated with homologous transfusion and a practical knowledge of treatment strategies and alternatives designed to reduce homologous blood exposure. Such a review cannot be encyclopedic. Our hope is that it will serve the reader as a stimulus to examine his or her transfusion practices and as a guide for future self-learning.