Retrospective analysis of bovine pericardium (Vascu-Guard) for patch closure in carotid endarterectomies

Long-term durability and clinical outcome of a prospective randomized trial comparing carotid endarterectomy with ACUSEAL polytetrafluoroethylene patching versus pericardial patching

BACKGROUND

Several studies have shown the superiority of carotid endarterectomy (CEA) with patch closure over primary closure. However, no definite study has shown any significant differences in clinical outcome between various types of patches. Because more vascular surgeons have used pericardial patching recently, this study will analyze the late clinical outcome (≥10 years) of our previously reported prospective randomized trial comparing CEA with ACUSEAL (polytetrafluoroethylene) vs pericardial patching.

METHODS

A total of 200 CEAs were randomized (1:1) to either Vascu-Guard pericardial patching or ACUSEAL patching. All patients had immediate duplex ultrasound imaging, which was repeated at 6 months and annually thereafter. Kaplan-Meier analysis was used to estimate rates of freedom from stroke, stroke-free survival, and rates of freedom from ≥50% and ≥80% restenosis.

RESULTS

Overall demographic and clinical characteristics were somewhat similar with a mean follow-up of 80 months (range: 0-149 months). The rates of freedom from stroke were 97, 97, 97, 96, 93 for ACUSEAL vs 99, 98, 97, 97, 92 for pericardial patching (P = .1112) at 1, 2, 3, 5, and 10 years, respectively. Similarly, the rates of freedom from stroke/death were 94, 93, 90, 76, 50 for ACUSEAL vs 99, 96, 91, 78, 47 for pericardial patching (P = .8591). The rates of freedom from ≥50% restenosis were 98, 98, 96, 89, 79 for ACUSEAL vs 87, 83, 83, 81, 71 for pericardial patching (P = .0489). The rates of freedom from ≥80% restenosis were 99, 99, 99, 96, 85 for ACUSEAL vs 96, 96, 96, 93, 93 for pericardial patching (P = .9407). The overall survival rates were 95, 94, 91, 77, 51 for ACUSEAL vs 100, 98, 93, 79, 50 for pericardial patching (P = .9123). Other patch complications (eg, rupture, aneurysmal dilation, infection, etc) were similar.

CONCLUSIONS

Both CEA with ACUSEAL (polytetrafluoroethylene) and pericardial patching are durable and have similar clinical outcomes at 10 years except that ACUSEAL patching has significantly better rates of freedom from ≥50% restenosis.

Selection criteria for patch angioplasty material in carotid endarterectomy

Background:

Carotid endarterectomy (CEA) with patch angioplasty has been favored due to its lower reoccurrence of restenosis compared to primary CEA. There are multiple types of patch angioplasty material available. However, selection of patch material is based on uncertain criteria. The aim of this study is to determine the ideal criteria for selecting the best patch material for CEA.

Methods:

We conducted a comprehensive literature search for studies that describe the ideal criteria for selecting patch material for CEA. We compiled all of the criteria mentioned into one table and selecting the criteria which were most frequently mentioned with a simple scoring system.

Results:

A total of 65 studies out of 784 studies were assessed for its full-text eligibility. Thus, we found 23 studies that were eligible for analysis. There are 22 ideal criteria that were mentioned in the analyzed studies. We grouped these criteria into physical characteristics, safety, contribution to hemodynamic, contribution in tissue healing, economic aspect, and ability to prevent postsurgical complication. We proposed 10 ideal criteria for guiding vascular surgeon in selecting the best patch angioplasty material.

Conclusion:

To this day, no material has been discovered which meets all ten criteria. This study’s proposed ideal criteria serve as the foundation for the creation of the best patch angioplasty material.

Recurrent pseudoaneurysm after carotid endarterectomy

Pseudoaneurysms and patch infections are known complications of carotid endarterectomy with patch angioplasty. Although they are rare occurrences, they carry high morbidity and almost uniformly require surgical intervention. Infectious pathogens are often gram-positive bacteria, most commonly Staphylococcus species, whereas gram-negative infections are less frequently observed. We present a case of recurrent pseudoaneurysm in a patient who had a carotid endarterectomy with bovine pericardial patch angioplasty complicated by Pasteurella multocida infection. This case demonstrates the need for recognition and consideration of a broad differential of pathogens in evaluating and treating vascular infections.

Durability of Carotid Endarterectomy with Bovine Pericardial Patch

BACKGROUND

Multiple studies have shown that patch angioplasty after carotid endarterectomy (CEA) reduces the risk of stroke and restenosis when compared with primary closure. Biological, synthetic, or vein patches have been traditionally used in CEA. This article reports the early and long-term outcomes of bovine pericardium (BP) for patch angioplasty in CEA.

METHODS

A retrospective, consecutive analysis of 874 patients who underwent CEA during the past 17 years at Mayo Clinic, Florida, was performed. BP patch (BPP) was used in 680 patients. Other CEA techniques were used in 194 patients (standard without patch, 78; standard with Dacron, 74; standard with vein patch, 16; and other techniques: bypasses, 26). We defined group 1 as those who underwent BPP angioplasty and group 2 as those who underwent all other techniques. Early and late clinical outcomes and patch-related complications (restenosis, infection, and hematoma) were recorded and analyzed.

RESULTS

Median follow-up for the entire series was 39.6 months. There were no statistically significant differences in 30-day mortality and morbidity between the 2 groups, except that BP group has less 30-day stroke (0.1%, 1 of 680) versus other techniques (1.5%, 3 of 194, P = 0.03). Thirty-day postoperative mortality rate was 0.1% (1 of 680) in BPP group and 1.0% (2 of 194) in other technique group (P = 0.13). No statistically significant difference was noted in 30-day postoperative major complications (transient ischemic attack [TIA], wound infection, hematoma requiring surgical evacuation, and nerve injury) between the 2 groups. Ten-year freedom from stroke/TIA were 97.8% in the BP group compared with 98.5% in the other group (P = 0.86). Ten-year freedom from restenosis was also similar between groups (89.0% BP vs. 90.4% others, P = 0.69). Ten-year survival rate was 38.4% in BP group and 45.0% in other technique group, and this was statistically significant on univariate analysis only.

CONCLUSIONS

CEA with BP angioplasty has excellent early and late outcomes with minor morbidity and mortality.

Extracellular Matrix Bioscaffolds as Immunomodulatory Biomaterials<sup/>

Suppression of the recipient immune response is a common component of tissue and organ transplantation strategies and has also been used as a method of mitigating the inflammatory and scar tissue response to many biomaterials. It is now recognized, however, that long-term functional tissue replacement not only benefits from an intact host immune response but also depends upon such a response. The present article reviews the limitations associated with the traditionally held view of avoiding the immune response, the ability of acellular biologic scaffold materials to modulate the host immune response and promote a functional tissue replacement outcome, and current strategies within the fields of tissue engineering and biomaterials to develop immune-responsive and immunoregulatory biomaterials.

Biologic Scaffolds

Biologic scaffold materials composed of allogeneic or xenogeneic extracellular matrix are commonly used for the repair and functional reconstruction of injured and missing tissues. These naturally occurring bioscaffolds are manufactured by the removal of the cellular content from source tissues while preserving the structural and functional molecular units of the remaining extracellular matrix (ECM). The mechanisms by which these bioscaffolds facilitate constructive remodeling and favorable clinical outcomes include release or creation of effector molecules that recruit endogenous stem/progenitor cells to the site of scaffold placement and modulation of the innate immune response, specifically the activation of an anti-inflammatory macrophage phenotype. The methods by which ECM biologic scaffolds are prepared, the current understanding of in vivo scaffold remodeling, and the associated clinical outcomes are discussed in this article.

Results of Carotid Endarterectomy Using Bovine Pericardium Patch Closure, with a Review of Pertinent Literature

Patch closure after carotid endarterectomy lowers risk of recurrent stenosis and perioperative neurologic events. Although vein patches have theoretic benefits, few differences between vein and nonautologous patches have been noted. Bovine pericardium has been increasingly used in carotid surgery over the last 15 years, with favorable reports. This study reviews a large carotid surgery series using this patch. Data were gathered on 464 consecutive carotid operations using the bovine pericardium patch; all complications were analyzed and pertinent literature review was performed. Of 464 procedures, 218 (47%) were performed for symptomatic disease. Total peri-operative ipsilateral stroke rate was 0.65 per cent. A low rate of postoperative bleeding was noted. Recurrence of >70 per cent stenosis was 1.6 per cent at follow-up of 26 months in 410 patients. Handling was subjectively described as excellent. Literature review comprising 3239 carotid operations revealed low risks of stroke, bleeding requiring intervention, or high rates of recurrent stenosis. Bovine pericardium patch angioplasty has low perioperative and late complications and good handling characteristics, making it an acceptable choice for use in carotid surgery.

Emerging Implications for Extracellular Matrix-Based Technologies in Vascularized Composite Allotransplantation

Despite recent progress in vascularized composite allotransplantation (VCA), limitations including complex, high dose immunosuppression regimens, lifelong risk of toxicity from immunosuppressants, acute and most critically chronic graft rejection, and suboptimal nerve regeneration remain particularly challenging obstacles restricting clinical progress. When properly configured, customized, and implemented, biomaterials derived from the extracellular matrix (ECM) retain bioactive molecules and immunomodulatory properties that can promote stem cell migration, proliferation and differentiation, and constructive functional tissue remodeling. The present paper reviews the emerging implications of ECM-based technologies in VCA, including local immunomodulation, tissue repair, nerve regeneration, minimally invasive graft targeted drug delivery, stem cell transplantation, and other donor graft manipulation.

Biologic scaffolds for regenerative medicine: mechanisms of in vivo remodeling

Successful regenerative medicine strategies for functional tissue reconstruction include the in situ placement of acellular materials composed of the extracellular matrix (ECM) or individual components of the ECM. The composition and ultrastructure of these materials vary depending on multiple factors including the tissue source and species from which the materials are harvested, the methods of manufacture, the efficiency of decellularization, post-processing modifications such as chemical cross-linking or solubilization, and the methods of terminal sterilization. Appropriately configured materials have the ability to modulate different stages of the healing response by inducing a shift from a process of inflammation and scar tissue formation to one of constructive remodeling and functional tissue restoration. The events that facilitate such a dramatic change during the biomaterial-host interaction are complex and necessarily involve both the immune system and mechanisms of stem cell recruitment, growth, and differentiation. The present manuscript reviews the composition of biologic scaffolds, the methods and recommendations for manufacture, the mechanisms of the biomaterial-host interaction, and the clinical application of this regenerative medicine approach.

Prospective randomized trial of ACUSEAL versus Vascu-Guard patching in carotid endarterectomy

BACKGROUND

Multiple studies have been conducted that demonstrate the superiority of patch angioplasty over primary closure for carotid endarterectomy (CEA). Patch angioplasty with polytetrafluorethylene patches (ACUSEAL) have shown results comparable to patch angioplasty with saphenous vein and polyester patches. This is a prospective randomized study to compare the clinical outcomes of CEA using ACUSEAL versus bovine pericardium patching (Vascu-Guard).

METHODS

Two hundred patients were randomized (1:1) to either ACUSEAL or Vascu-Guard patching. Demographic data/clinical characteristics were collected. Intraoperative hemostasis times and the frequency of reexploration for neck hematoma were recorded. All patients received immediate and 1-month postoperative duplex ultrasound studies, which were repeated at 6-month intervals. A Kaplan-Meier analysis was used to estimate the risk of restenosis and the stroke-free survival rates.

RESULTS

The demographics were similar in both groups, except for a higher incidence of current smokers in the ACUSEAL group and more patients with congestive heart failure in the Vascu-Guard group (P = 0.02 and 0.03, respectively). The mean operative internal carotid artery diameter and the mean arteriotomy length were similar in both groups. The mean hemostasis time was 4.90 min for ACUSEAL patching vs. 3.09 min for Vascu-Guard (P = 0.027); however, the mean operative times were similar for both groups (ACUSEAL 2.09 hr vs. Vascu-Guard 2.16 hr, P = 0.669). The incidence of reexploration for neck hematoma was higher in the Vascu-Guard group; 6.12% vs. 1.03% (P = 0.1183). The incidence of perioperative ipsilateral neurologic events was 3.09% for ACUSEAL patching vs. 1.02% for Vascu-Guard patching (P = 0.368). The mean follow-up period was 15 months. The respective freedom from ≥70% carotid restenosis at 1, 2, and 3 years were 100%, 100%, and 100% for ACUSEAL patching vs. 100%, 98%, and 98% for Vascu-Guard patching (P = 0.2478). The ipsilateral stroke-free rates at 1, 2, and 3 years were 96% for ACUSEAL and 99% for Vascu-Guard patching.

CONCLUSIONS

Although CEA patching with ACUSEAL versus Vascu-Guard differed in hemostasis time, the frequency of reexploration for neck hematomas was more frequent in the pericardial patch group; however, only 1 patient had documented suture line bleeding and the surgical reexploration rate is not likely to be patch related. There were not any significant differences in perioperative/late neurologic events and late restenosis in the 2 groups.

Use of the vascu-guard bovine pericardium patch for arteriotomy closure in carotid endarterectomy. Early and long-term results

BACKGROUND

To report the early and long-term results of Vascu-Guard bovine pericardium (BP) for patch angioplasty in carotid endarterectomy (CEA).

METHODS

We retrospectively analyzed the data of 256 CEAs with BP patch closure performed in 238 patients during the past 12 years in our department. Patch-related complications (restenosis, infection, and aneurysm formation) and early and late (12 to 144 months follow-up) clinical outcomes were recorded and statistically analyzed.

RESULTS

Thirty-day postoperative stroke rate was 1.2% (3/256) with zero mortality. Major complications occurred in 3.5% (9 of 256) of the procedures and cranial nerve injury in 4.3% (11 of 256). At 12 years, cumulative estimates of freedom from any stroke, stroke-free survival, and freedom from restenosis were 88.4% (standard error [SE]: 3.3%), 60% (SE: 7.8%), and 98.3% (SE: 0.8%), respectively. No patient experienced patch infection or aneurysm formation.

CONCLUSIONS

This series shows the efficacy, safety, and durability of CEA with BP patch closure, in both the short and long term. BP combines the advantages of vein and synthetic patches, representing a suitable option when performing CEA.

Pericardial patch ring Roux-en-Y gastric bypass: a preliminary report

BACKGROUND

Laparoscopic Roux-en-Y gastric bypass (RYGB) is an effective treatment for morbid obesity. Failure of weight loss has been reported in 10 to 30% of RYGB patients. Silastic ring RYGB was introduced to minimize failure rate, however, with higher complication rate. The aim of our study is to evaluate the safety of utilizing pericardial patch as a ring on RYGB patients.

METHODS

Between March 2010 and June 2011, a total of 189 patients underwent pericardial patch ring RYGB at the Bariatric and Laparoscopy Center. A retrospective review of a prospectively collected database was performed for all pericardial patch ring RYGB patients, noting the outcomes and complications of the procedure.

RESULTS

Pericardial patch ring RYGB patients demonstrated a mean percentage of excess weight loss of 57.4% at a mean follow-up of 11 months. Out of 164 patients with follow-up, five (3.0%) patients required endoscopic balloon dilation due to dysphagia, abdominal pain, and/or gastric outlet obstruction. All patients did well after the procedure. Three (1.8%) patients underwent diagnostic laparoscopy for abdominal pain. Of these patients, one (0.6%) had dilated and enlarged blind limb, and two (1.2%) patients had partial small bowel obstruction. No patient was readmitted or reoperated due to pericardial patch ring.

CONCLUSIONS

Longer follow-up is needed to prove the true efficacy of this procedure in reducing weight gain. Pericardial patch ring RYGB seems to be a safe alternative for banded RYGB of other materials.

Reconstruction of portal vein and superior mesenteric vein after extensive resection for pancreatic cancer

PURPOSE

Tumor invasion to the portal vein (PV) or superior mesenteric vein (SMV) can be encountered during the surgery for pancreatic cancer. Venous reconstruction is required, but the optimal surgical methods and conduits remain in controversies.

METHODS

From January 2007 to July 2012, 16 venous reconstructions were performed during surgery for pancreatic cancer in 14 patients. We analyzed the methods, conduits, graft patency, and patient survival.

RESULTS

The involved veins were 14 SMVs and 2 PVs. The operative methods included resection and end-to-end anastomosis in 7 patients, wedge resection with venoplasty in 2 patients, bovine patch repair in 3 patients, and interposition graft with bovine patch in 1 patient. In one patient with a failed interposition graft with great saphenous vein (GSV), the SMV was reconstructed with a prosthetic interposition graft, which was revised with a spiral graft of GSV. Vascular morbidity occurred in 4 cases; occlusion of an interposition graft with GSV or polytetrafluoroethylene, segmental thrombosis and stenosis of the SMV after end-to-end anastomosis. Patency was maintained in patients with bovine patch angioplasty and spiral vein grafts. With mean follow-up of 9.8 months, the 6- and 12-month death-censored graft survival rates were both 81.3%.

CONCLUSION

Many of the involved vein segments were repaired primarily. When tension-free anastomosis is impossible, the spiral grafts with GSV or bovine patch grafts are good options to overcome the size mismatch between autologous vein graft and portomesenteric veins. Further follow-up of these patients is needed to demonstrate long-term patency.

Restenosis after microsurgical non-patch carotid endarterectomy in 586 patients

Background

Carotid endarterectomy (CEA) reduces the risk of stroke in patients with symptomatic (>50%) and asymptomatic (>60%) carotid artery stenosis. Here we report the midterm results of a microsurgical non-patch technique and compare these findings to those in the literature.

Methods

From 1998 to 2009 we treated 586 consecutive patients with CEA. CEA was performed, under general anesthesia, with a surgical microscope using a non-patch technique. Somatosensory evoked potential and transcranial Doppler were continuously monitored. Cross-clamping was performed under EEG burst suppression and adaptive blood pressure increase. Follow-up was performed by an independent neurologist. Mortality at 30 days and morbidity such as major and minor stroke, peripheral nerve palsy, hematoma and cardiac complications were recorded. The restenosis rate was assessed using duplex sonography 1 year after surgery.

Results

A total of 439 (75%) patients had symptomatic and 147 (25%) asymptomatic stenosis; 49.7% of the stenoses were on the right-side. Major perioperative strokes occurred in five (0.9%) patients [n = 4 (0.9%) symptomatic; n = 1 (0.7%) asymptomatic patients]. Minor stroke was recorded in six (1%) patients [n = 4 (0.9%) symptomatic; n = 2 (1.3%) asymptomatic patients]. Two patients with symptomatic stenoses died within 1 month after surgery. Nine patients (1.5%) had reversible peripheral nerve palsies, and nine patients (1.5%) suffered a perioperative myocardial infarction. High-grade (>70%) restenosis at 1 year was observed in 19 (3.2%) patients [n = 12 (2.7%) symptomatic; n = 7 (4.7%) asymptomatic patients].

Conclusions

The midterm rate of restenosis was low when using a microscope-assisted non-patch endarterectomy technique. The 30-day morbidity and mortality rate was comparable or lower than those in recently published surgical series.

Ten-year comparative analysis of bovine pericardium and autogenous vein for patch angioplasty in patients undergoing carotid endarterectomy

BACKGROUND

To evaluate early and late clinical outcomes of carotid endarterectomy (CEA) with bovine pericardium patch in comparison with autogenous vein.

METHODS

During a 10-year period, 456 CEAs were performed using patch closure of the arteriotomy with bovine pericardium (252 cases) and autogenous vein (204 cases). Retrospectively, surgical outcomes were evaluated and compared regarding CEA-related parameters, early and late mortality and morbidity rates, and the incidence of restenosis and aneurysmal dilatation between patients with bovine pericardium patch closure and those with autogenous vein closure.

RESULTS

The two groups were comparable regarding basic demographics, clinical data, and anatomic data, except the incidence of coronary or peripheral arterial diseases. In patients with bovine pericardium patch closure, the total operating time and carotid clamping duration were statistically significantly shorter than in those with autogenous vein closure (P < 0.01). During the early postoperative period, 10 major (stroke and death) complications (2.2%) occurred without statistically significant difference between the two groups. The incidence of early minor postoperative complications was less with bovine pericardium patch closure (5.6% vs. 10.8%; P < 0.05). With a mean follow-up of 62 months for bovine pericardium patch closure and 67 months for autogenous vein closure, the incidence of restenosis was similar, but aneurysmal dilatation was higher in patients with autogenous vein closure with a statistically significant difference (0% vs. 2.0%; P < 0.05).

CONCLUSION

CEA with bovine pericardium patch angioplasty showed excellent early and late clinical outcomes. Our results demonstrated bovine pericardium to be a suitable patch material for routine use in CEA.

Bovine pericardium retail preserved in glutaraldehyde and used as a vascular patch

Background

In this study we evaluated the performance of bovine pericardium preserved in glutaraldehyde used as a vascular patch.

Methods

Fourteen young pigs, six females and eight males, weighting 10.3 - 18.4 kg were used in our study. We implanted three remnants in each pig, two in the abdominal aorta and one was juxtaposed to the peritoneum. The smooth face (SF) and rough face (RF) of each remnant were implanted turned to the vessel inner portion and one remnant was juxtaposed to the peritoneum. The animals were sacrificed in 4.5 - 8 months after surgery (75 - 109 kg). The remnants were assessed for aorta wall, fibroses formation in inner apposition and calcification related to the face turned to the vessel inner portion.

Results

The rough face showed a lower dilatation level compared to the face implanted in adjacent aorta. There was no difference between intensity and/or incidence of graft calcification when the superficies were compared. The bovine pericardium preserved in glutaraldehyde did not show alterations in its structure when implanted with different faces turned to the inner portion of vessel.

Conclusion

When turned to the inner portion of the vessel, the rough face of the remnant presented a lower dilatation in relation to the adjacent aorta and a better quality of endothelium layer and did not show a difference between intensity and/or incidence of graft calcification.