COVID-19-Associated Carotid Atherothrombosis and Stroke

We present a radiology-pathology case series of 3 patients with coronavirus disease 2019 (COVID-19) with acute ischemic stroke due to fulminant carotid thrombosis overlying mild atherosclerotic plaque and propose a novel stroke mechanism: COVID-associated carotid atherothrombosis.

Increasing incidence of midterm and long-term complications after endovascular graft repair of abdominal aortic aneurysms: a note of caution based on a 9-year experience

OBJECTIVE

To analyze the late complications after endovascular graft repair of elective abdominal aortic aneurysms (AAAs) at the authors' institution since November 1992.

SUMMARY BACKGROUND DATA

Recently, the use of endovascular grafts for the treatment of AAAs has increased dramatically. However, there is little midterm or long-term proof of their efficacy.

METHODS

During the past 9 years, 239 endovascular graft repairs were performed for nonruptured AAAs, many (86%) in high-risk patients or in those with complex anatomy. The grafts used were Montefiore (n = 97), Ancure/EVT (n = 14), Vanguard (n = 16), Talent (n = 47), Excluder (n = 20), AneuRx (n = 29), and Zenith (n = 16). All but the AneuRx and Ancure repairs were performed as part of a U.S. phase 1 or phase 2 clinical trial under a Food and Drug Administration investigational device exemption. Procedural outcomes and follow-up results were prospectively recorded.

RESULTS

The major complication and death rates within 30 days of endovascular graft repair were 17.6% and 8.5%, respectively. The technical success rate with complete AAA exclusion was 88.7%. During follow-up to 75 months (mean +/- standard deviation, 15.7 +/- 6.3 months), 53 patients (22%) died of unrelated causes. Two AAAs treated with endovascular grafts ruptured and were surgically repaired, with one death. Other late complications included type 1 endoleak (n = 7), aortoduodenal fistula (n = 2), graft thrombosis/stenosis (n = 7), limb separation or fabric tear with a subsequent type 3 endoleak (n = 1), and a persistent type 2 endoleak (n = 13). Secondary intervention or surgery was required in 23 patients (10%). These included deployment of a second graft (n = 4), open AAA repair (n = 5), coil embolization (n = 6), extraanatomic bypass (n = 4), and stent placement (n = 3).

CONCLUSION

With longer follow-up, complications occurred with increasing frequency. Although most could be managed with some form of endovascular reintervention, some complications resulted in a high death rate. Although endovascular graft repair is less invasive and sometimes effective in the long term, it is often not a definitive procedure. These findings mandate long-term surveillance and prospective studies to prove the effectiveness of endovascular graft repair.

Efficacy of a proximal occlusion catheter with reversal of flow in the prevention of embolic events during carotid artery stenting: an experimental analysis

OBJECTIVE

The role of percutaneous angioplasty and stenting of carotid bifurcation lesions has been limited by its potential for producing embolic debris. We evaluated the efficacy of a proximal occlusion catheter (POC) in the prevention of embolic events during carotid artery stenting. In addition, pressure measurements relevant to the clinical application of this device were obtained from 10 patients undergoing carotid endarterectomy.

METHODS

The POC is a guiding catheter with an occlusion balloon attached on the outside of the catheter at its distal end. Occlusion of the common carotid artery (CCA) was achieved by inflating the balloon while access to carotid bifurcation lesions was obtained through the inner lumen. The POC was inserted in the CCA of 10 dogs via the femoral artery. The side port of the POC was connected to a sheath placed in the femoral vein, thereby creating an external arteriovenous shunt. Ten artificial radiopaque particles simulating embolic particles and contrast agent were introduced in the CCA and monitored fluoroscopically. As a control, the same procedure was performed with a standard guiding catheter without an occlusion balloon. In 10 patients undergoing carotid endarterectomy, the internal carotid artery (ICA) and external carotid artery stump pressures and the pressure in the internal jugular vein were measured.

RESULTS

Without the external arteriovenous shunt, in all animals there was prograde flow in the distal CCA despite CCA occlusion. This flow was derived from the thyroid artery. However, once the arteriovenous shunt was activated, reversal of flow in the distal CCA was achieved in each animal, and all the artificial particles were recovered from the side port of the POC. In the control group, each particle embolized to the brain (100%, P <.01). In the patients, the mean stump pressures in the ICA and external carotid artery and the jugular vein pressure were 51.8 +/- 14.2, 62.2 +/- 15.1, and 6.5 +/- 3.5 mm Hg, respectively. In each case, the jugular vein pressure was the lowest among the three.

CONCLUSIONS

Obtaining proximal CCA control by inflating the POC does not sufficiently prevent embolization. However, reversal of flow in the ICA can always be created with the external shunt, which effectively prevents embolization. Thus, POC may markedly lower procedural stroke rates during carotid artery stenting. The ability of POC to prevent embolization before crossing the lesion with a guidewire may be an important advantage over other distal protection devices.

Diameter changes in isolated iliac artery aneurysms 1 to 6 years after endovascular graft repair

OBJECTIVE

Precise diameter changes in iliac artery aneurysms (IAAs) after endovascular graft (EVG) repair are yet to be determined. This report describes the midterm size changes in isolated IAAs 13 to 72 months after treatment with an EVG.

METHODS

From January 1993 to April 1999, 31 patients with 35 true isolated IAAs (32 common iliac and 3 hypogastric) had these lesions treated with EVGs and coil embolization of the hypogastric artery or its branches. The EVG used in this study consisted of a balloon-expandable stent attached to a polytetrafluoroethylene graft. Contrast-enhanced spiral computed tomographic scans were performed at 3- to 6-month intervals to follow the aneurysms for change in diameter and endoleaks.

RESULTS

Thirty patients had a decrease in the size of their iliac aneurysms with EVG repair. All EVGs remained patent. All patients, except for one, were followed up for 13 to 72 months (mean, 31 months). The pretreatment aneurysm size ranged from 2.5 to 11.0 cm in diameter (mean, 4.6 +/- 1.62 cm). After EVG treatment, the aneurysms ranged from 2.0 to 8.0 cm in diameter (mean, 3.8 +/- 1.36 cm). The change in aneurysm diameter ranged from 0.5 to 3.1 cm (mean, 1.1 +/- 0.62 cm) with an average change of -0.516 +/- 0.01 cm/y for the first year. Five patients died of their intercurrent medical conditions during the follow-up period. One of the patients had a new endoleak and an increase in common iliac aneurysm size 18 months after EVG treatment, despite an early contrast-enhanced computed tomographic scan that showed no endoleak. This patient's aneurysm ruptured, and a standard open surgical repair was successfully performed. Another patient had a decrease in hypogastric aneurysm size after EVG treatment and no radiographic evidence of an endoleak, but eventually the aneurysm ruptured. He was successfully treated with a standard open surgical repair.

CONCLUSIONS

EVGs can be an effective treatment for isolated IAAs. Properly treated with EVGs, IAAs decrease in size. The enlargement of an IAA, even if no endoleak can be detected, appears to be an ominous sign suggestive of an impending rupture. IAAs that enlarge should be closely evaluated for an endoleak. If an endoleak is detected, it should be eliminated if possible. If an endoleak cannot be found, open surgical repair should be considered.

Alternative techniques for management of distal anastomoses of aortofemoral and iliofemoral endovascular grafts

PURPOSE

Techniques for managing the distal anastomoses of aortofemoral and iliofemoral endovascular grafts are described.

METHODS

Over a 2(1/2)-year period 46 endovascular grafts were successfully placed to treat severe iliac artery occlusive disease. Endovascular grafts were anchored proximally in the distal aorta or iliac arteries with Palmaz balloon-expandable stents. The distal anastomoses were performed with the use of open, sutured anastomotic techniques. In contrast to stented distal anastomoses, these techniques allowed us to (1) treat occlusive lesions extending from the distal aorta to below the inguinal ligament, (2) terminate endovascular grafts in the groin where stents are contraindicated, (3) vary the distal anastomotic site depending on the local pattern of disease, and (4) standardize the preinsertion length of the endovascular graft.

RESULTS

Two distal perianastomotic stenoses and one graft occlusion were detected postoperatively in 11 bypass grafts that had distal anastomoses sewn endoluminally without an overlying patch angioplasty. Only one perianastomotic stenosis was found among 35 anastomoses performed with other techniques. There were no significant differences in primary and secondary patency between grafts originating in the distal aorta or iliac arteries.

CONCLUSIONS

Hand-sewn distal anastomoses can simplify the insertion of endovascular grafts used for the treatment of aortoiliac occlusive disease. These anastomoses permit tailoring of the graft according to the patients' pattern of disease and eliminate the need to precisely measure the length of the graft preoperatively. In addition, because a distal stent is not required, endovascular grafts can be safely terminated in the groin instead of the external iliac artery where disease progression can lead to graft failure. Finally, endovascular distal anastomoses should be closed with a patch or the hood of a more distal bypass graft to prevent perianastomotic stenoses or occlusions in the postoperative period.

Can duplex scan arterial mapping replace contrast arteriography as the test of choice before infrainguinal revascularization?

PURPOSE

Arteriography is the diagnostic test of choice before lower extremity revascularization, because it is a means of pinpointing stenotic or occluded arteries and defining optimal sites for the origin and termination of bypass grafts. We evaluated whether a duplex ultrasound scan, used as an alternative to arteriography, could be used as a means of accurately predicting the proximal and distal anastomotic sites in patients requiring peripheral bypass grafts and, therefore, replace standard preoperative arteriography.

METHODS

Forty-one patients who required infrainguinal bypass grafts underwent preoperative duplex arterial mapping (DAM). Based on these studies, an observer blinded to the operation performed predicted what operation the patient required and the best site for the proximal and distal anastomoses. These predictions were compared with the actual anastomotic sites chosen by the surgeon.

RESULTS

Whether a femoropopliteal or an infrapopliteal bypass graft was required was predicted correctly by means of DAM in 37 patients (90%). In addition, both anastomotic sites in 18 of 20 patients (90%) who had femoropopliteal bypass grafts and 5 of 21 patients (24%) who had infrapopliteal procedures were correctly predicted by means of DAM.

CONCLUSION

DAM is a reliable means of predicting whether patients will require femoropopliteal or infrapopliteal bypass grafts, and, when a patient requires a femoropopliteal bypass graft, the actual location of both anastomoses can also be accurately predicted. Therefore, DAM appears able to replace conventional preoperative arteriography in most patients found to require femoropopliteal reconstruction. Patients who are predicted by means of DAM to require crural or pedal bypass grafts should still undergo preoperative contrast studies to confirm these results and to more precisely locate the anastomotic sites.

Congenital diaphragmatic hernia: survival treated with very delayed surgery, spontaneous respiration, and no chest tube

This report suggests that stabilization of the intrauterine to extrauterine transitional circulation combined with a respiratory care strategy that avoids pulmonary overdistension, takes advantage of inherent biological cardiorespiratory mechanics, and very delayed surgery for congenital diaphragmatic hernia results in improved survival and decreases the need for extracorporeal membrane oxygenation (ECMO). This retrospective review of a 10-year experience in which the respiratory care strategy, ECMO availability, and technique of surgical repair remained essentially constant describes the evolution of this method of management of congenital diaphragmatic hernia.