Blowout of carotid venous patch angioplasty

Experimental comparative assay of tensile resistance of greater saphenous vein from ankle and groin

Background

The great saphenous vein is used as patch material in several types of arterial reconstruction, including trauma and carotid and femoral endarterectomy. There have been reports of saphenous patch blowout, particularly of patches constructed with veins harvested from the ankle. There is a need for objective measurement of the resistance of saphenous vein tissues.

Objectives

To measure the tensile strength of the great saphenous vein harvested at the ankle and groin and analyze the correlation between diameter and tissue strength.

Methods

Venous samples were harvested during elective saphenous stripping in patients with symptomatic varicose veins. Only segments without reflux were included. Ten limbs from eight patients were studied, providing 20 samples in total. Venous segments were opened along their longitudinal axis and fitted to electronic traction assay equipment to obtain values for material maximum tension in kilograms-force per square centimeter (kgf/cm²; the maximum force resisted by the segment, divided by its cross-sectional area).

Results

The average maximum tension in the ankle saphenous vein group ranged from 74.02 to 190.10 kgf/cm² and from 13.53 to 69.45 kgf/cm2 in the groin saphenous vein group (p < 0.0001). The Pearson coefficient for the correlation between vein diameter and maximum tension was -0.852 (moderate to strong inverse correlation).

Conclusions

Ankle saphenous vein tissue from female patients operated for varicose veins has significantly higher resistance than saphenous vein tissue from the groin and there is an inverse relation between vein diameter and resistance of tissue from the same population.

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.

Outcomes of Carotid Endarterectomy with Primary Closure

Carotid endarterectomy (CEA) reduces the risk of stroke in patients with internal carotid artery stenosis, although the optimal surgical technique is debated. The literature suggests that patch angioplasty reduces complication risk, although primary closure shortens cross-clamp time and eliminates complications associated with grafts. The objective of this study was to assess the complication rate after CEA with primary closure. Retrospective review of 240 consecutive patients between 2002 and 2010. Of these patients, 70% returned for follow-up visits for at least 2 or more years. Primary closure was used in all patients. The average cross-clamp time was 18 minutes. Complications in the immediate postoperative period within 30 days were as follows: stroke (n = 3; 1.1%), transient ischemic attack (TIA; n = 4; 1.5%), myocardial infarction (MI; n = 3; 1.1%), and death (n = 1; 0.4%). Short-term follow-up revealed eight patients who were found to have significant restenosis (>80%) by carotid duplex imaging. Two to ten year postoperative complication rates were as follows: stroke (n = 7; 4.2%), TIA (n = 7; 4.2%), amaurosis fugax (n = 1; 0.6%), MI (n = 8; 4.8%), and death (n = 28; 17%). Mortality was due to stroke or heart attack (n = 2; 1.2%), cancer (n = 7; 4.2%), and unknown causes (n = 19; 11%). This study presents our experience with complications after primary closure after CEA. In our experience, CEA is a safe and effective surgical means of preventing stroke in the short term. Well-designed prospective studies are needed to confirm specific patient characteristics in which primary closure and patch angioplasty are indicated.

Selective Patch Angioplasty and Intraoperative Shunting in Carotid Endarterectomy: A Single-Center Review of 141 Procedures

Objective: Open surgical treatment of carotid artery stenosis, namely, carotid endarterectomy (CEA), has evolved since its inception in 1953. Despite improvements in the treatment of carotid occlusive disease through technological and surgical innovations, the use of patch grafting in CEA’s remains controversial. We evaluate the durability of the primary closure and the safety of selective shunting during carotid endarterectomy (CEA) as determined by intraoperative EEG and postoperative outcomes.

Methods: A consecutive series of CEA’s performed by the senior author at a single academic medical center from 2001 to 2012 were reviewed. All cases were performed under continuous intraoperative electroencephalography (EEG). Patch angioplasty was used in cases where there was tortuosity of the vessel within the region of the endarterectomy and narrow vessel diameter at the distal end of the arteriotomy. Shunting was used when intraoperative EEG showed a > 50% reduction in a waveform in any lead. Patients were evaluated for restenosis via imaging or ultrasound at six months and subsequently annual follow-up.

Results: One hundred and forty-one CEA’s were performed on 132 (76 male, 56 female) patients with an average age of 71 years (range: 40–95 years). Four (3%) cases required patch angioplasty and three (2%) required intraoperative shunts. The cross-clamp time ranged from 22 to 74 minutes, and the duration increased with the use of shunts and patches. Complications were rare and included recurrent stenosis (n=2), postoperative transient ischemic attack (n=1), ischemic stroke in (n=1), temporary hypoglossal nerve weakness (n=2), temporary marginal mandibular nerve weakness (n=6), and neck hematoma (n=1).

Conclusion: Intraoperative EEG data suggests that primary closure and selective shunting in CEA can result in outcomes comparable with routine patch angioplasty and shunting.

Patches for carotid artery endarterectomy: current materials and prospects

Patch angioplasty is commonly performed after carotid endarterectomy. Randomized prospective trials and meta-analyses have documented improved rates of perioperative and long-term stroke prevention as well as reduced rates of restenosis for patches compared with primary closure of the arteriotomy. Although use of vein patches is considered to be the gold standard for patch closure, newer generations of synthetic and biologic materials rival outcomes associated with vein patches. Future bioengineered patches are likely to optimize patch performance, both by achieving minimal stroke risk and long-term rates of restenosis as well as by minimizing the risk of unusual complications of prosthetic patches such as infection and pseudoaneurysm formation. In addition, lessons from bioengineered patches will likely enable construction of bioengineered and tissue-engineered bypass grafts.

Resistência tensional do pericárdio bovino fixado em glutaraldeído comparada com a da veia safena magna

CONTEXTO: O uso do pericárdio bovino como remendo na endarterectomia de carótida é uma alternativa à veia safena magna. As vantagens do pericárdio incluem facilidade de obtenção, menor tempo operatório e principalmente menor índice de ruptura. OBJETIVO: Avaliar a resistência tensional do pericárdio bovino tratado com glutaraldeído e compará-la com a da veia safena magna. MÉTODOS: Os remendos de pericárdio bovino (grupo I, n = 20) e de veia safena magna (grupo II, n = 20) foram recortados em dimensões iguais (50 x 5 mm) e preparados de modo habitual a sua utilização. Os grupos foram submetidos a ensaio de tração e comparados em relação a força de ruptura, força máxima e tensão de ruptura utilizando-se o teste t de Student. A correlação da espessura do remendo com a força de ruptura também foi analisada utilizando-se o coeficiente de correlação linear de Pearson. RESULTADOS: Os parâmetros força de ruptura e força máxima foram significativamente maiores no grupo dos remendos de pericárdio bovino: 1,97 versus 1,36 kgf (p = 0,001230) e 2,27 versus 1,51 kgf (p = 0,0001087), respectivamente. A tensão de ruptura média para o material pericárdio bovino também foi maior (193,99±43,05 versus 49,19±22,96 kgf/cm², p = 7,603e-16) do que na veia safena. A correlação entre a espessura e a força de ruptura foi considerada moderada (r = 0,5032993) para o pericárdio bovino e baixa (r = 0,3062166) para o grupo da veia safena. CONCLUSÃO: Os autores concluem que a resistência do pericárdio bovino à ruptura foi considerada adequada neste estudo, e é significativamente maior que a da veia safena magna, retirada da região da coxa. Além disso, a espessura do remendo em ambos os grupos não apresenta boa correlação com sua resistência a ruptura.

Sequential cohort study of Dacron patch closure following carotid endarterectomy

BACKGROUND

Carotid endarterectomy reduces the risk of stroke and death in patients with severe carotid artery stenosis. This study examined whether the technique used to close the arteriotomy influenced the rate of perioperative transient ischaemic attack (TIA), stroke or death.

METHODS

A cohort of 236 patients undergoing carotid endarterectomy at a single centre was studied; 117 patients had primary closure of the arteriotomy and 119 patients in a sequential series had closure with a Dacron patch. A standard endarterectomy with completion intraoperative duplex imaging and digital subtraction angiography was used throughout.

RESULTS

Patch closure was associated with a significant reduction in the 30-day combined death, stroke and TIA rate: 10.3 per cent for primary closure versus 2.5 per cent for patch closure (P = 0.017). The risk of any cerebral event (stroke or TIA) was also significantly reduced (7.7 versus 1.7 per cent; P = 0.033). Residual stenosis on completion angiography was more common after primary closure (24.6 versus 7.4 per cent; P = 0.003).

CONCLUSION

Dacron patch closure had a higher technical success rate on completion imaging and was associated with a significant reduction in the risk of perioperative stroke, TIA and death.

Postoperative complications of carotid patching: pseudoaneurysm and infection

Patch angioplasty after carotid endarterectomy has been advocated to improve results by decreasing the incidence of recurrent stenosis and postoperative carotid thrombosis. Aneurysmal and infectious complications may be secondary to use of prosthetic materials in arterial reconstruction. We report four patients who developed late operative site complications related to carotid patching. All four of our patients had delayed pseudoaneurysms and three had infection related to the Dacron patch. In a typical case, a 57-year-old who had a right carotid endarterectomy in 1994 presented with a 1-month history of an enlarging right neck mass 7 years later. Imaging revealed a 6 x 4 cm pseudoaneurysm originating from an opening between the patch graft and the old endarterectomized carotid wall. Analysis of the literature disclosed an additional 45 patients who had pseudoaneurysms and/or infection related to carotid patching, most frequently with Dacron. We postulate that a low-grade Staphylococcus epidermidis infection of the foreign body patch may be the etiology. Autogenous saphenous vein interposition graft and antimicrobials effective against gram-positive organisms corrected the pseudoaneurysm. Although the benefits of routine carotid patching may include a decrease in restenosis, this advantage must be weighed against the risk of late pseudoaneurysm and/or infection when a prosthetic patch is used to closed the endarterectomy site.

Saphenous vein versus polytetrafluoroethylene carotid patch angioplasty

BACKGROUND

The optimal material for carotid patch angioplasty after endarterectomy remains uncertain. This study compares the early outcome and recurrent stenosis rates between saphenous vein (SV) and expanded polytetrafluoroethylene (ePTFE) carotid patch angioplasty.

METHODS

The results of 421 consecutive carotid endarterectomies performed over a 72-month period were reviewed. Postoperative complications and restenosis rates, defined as > OR = 60% narrowing measured by color flow duplex, were compared.

RESULTS

Patch angioplasty was performed with SV in 287 and with ePTFE in 110 cases. Patients who had undergone primary closure (n = 20) or whose form of closure was unknown (n = 4) were excluded. The mean age of patients and length of follow-up was similar between groups. Women were more likely to be patched with ePTFE than were men (36% versus 23%, P = 0.02). One death occurred in each group (0.3% SV, 0.9% ePTFE, P = 0.47), and four strokes occurred in each group (1.4% SV, 3.6% ePTFE, P = 0.22). Cervical hematomas requiring operative evacuation occurred in five SV closures and in three ePTFE closures (1.7% versus 2.7%, P = 0.69). Vein harvest site complications occurred in 6 patients (2%) who had undergone SV patch angioplasty. Recurrent stenosis occurred in 3 patients with SV closure and in 3 patients with ePTFE closure (1.0% versus 2.7%, P = 0.35). The 60-month restenosis rates by life table analysis were 2.6% +/- 2.1% for SV and 10.7% +/- 7.9% for ePTFE (P = 0.17).

CONCLUSIONS

The incidence of postoperative complications is similar with SV or ePTFE patch angioplasty; however, vein harvest site complications are avoided with the use of ePTFE. Recurrent stenosis at 5 years occurs infrequently with either SV or ePTFE.

Acute platelet deposition after carotid endarterectomy in sheep: vein patch compared with gelatin-sealed Dacron and polytetrafluoroethylene patch closure

PURPOSE

Patch angioplasty is commonly used to close the arteriotomy after carotid endarterectomy is performed. The purpose of this study was to determine whether any significant variations were present in platelet deposition for different patch sizes and materials.

METHOD

The study measured 111-indium-labeled uptake in the sheep to compare thrombus deposition for three different patch materials: autologous vein, gelatin-sealed Dacron, and polytetrafluoroethylene and for 6- and 12-mm patch widths. Platelet uptake was measured on the patch itself and on the artery wall that was opposite to the patch and that had undergone endarterectomy. Scanning electron microscopy was used to confirm the localization of the labeled platelets on the patch and on the surface that had undergone endarterectomy.

RESULTS

Although considerable variation was seen among animals, platelet accumulation was lowest in the vein patches compared with the prosthetic patches (p < 0.01), but the deposition on the gelatine-sealed Dacron was not significantly different from that on polytetrafluoroethylene patches. Platelet deposition on the artery wall that had undergone endarterectomy was considerably less than on the patch but was higher when a synthetic patch was used rather than a vein patch (p < 0.05).

CONCLUSIONS

Acute thrombus deposition after carotid endarterectomy was considerably less for vein patch closure than for synthetic patches. A 6-mm patch width caused less thrombus deposition both on the patch itself and on the artery wall compared with a 12-mm patch, but the difference was proportional to the patch width.

Surgical treatment of recurrent carotid artery stenosis

Ninety-two surgical procedures were performed in 82 patients for recurrent carotid artery stenosis. The etiology was recurrent atherosclerosis in 45 cases, myointimal hyperplasia in 20, organized thrombus without a significant underlying plaque in 20, and scarring along the proximal arteriotomy site in seven. The operations included a repeat endarterectomy in 66 cases and reconstruction with an interposition graft in 22. All five major neurological complications occurred in symptomatic patients, and included three instances of intraoperative embolization during exposure of the carotid artery. The majority of neurological complications occurred in symptomatic patients who had intraluminal thrombus confirmed at surgery. There were four perioperative deaths, due to cerebral hemorrhage in two patients and myocardial infarction in two. In the patients whose original surgery was performed at the Mayo Clinic, the risk of recurrent carotid artery stenosis was 3.1% with a primary closure compared to 1.6% when a patch graft was used. These results indicate that surgery for recurrent carotid artery stenosis is technically more difficult and carries a significantly higher risk than surgery for primary disease. The difficulty is due to the friable recurrent plaque associated with intraluminal thrombus, which increases the risk of embolization during carotid artery exposure. In the majority of patients with recurrent atherosclerosis, a repeat endarterectomy can be achieved. However, in some patients, there is scarring without a definite plane of cleavage between the recurrent disease and the underlying media, making an endarterectomy difficult. In these cases, excision of the diseased segment and reconstruction with an interposition graft is the best treatment. The findings presented here also suggest that closure of the original arteriotomy with a patch graft decreases the risk of recurrent carotid artery stenosis.