Combined Surgical and Endovascular Removal of Thrombus Entirely Occluding a Bifurcated Aortic Stent-Graft

Purpose:

To explore a method combining interventional, endovascular, and conventional surgical techniques for treating a completely occluded bifurcated stent-graft after endovascular aortic aneurysm repair.

Methods and Results:

A 60-year-old patient underwent endovascular repair of an abdominal aortic aneurysm (AAA) with a Talent bifurcated stent-graft. Five months later, after chronic thrombotic occlusion of the right iliac limb, he presented with acute occlusion of the entire stent-graft. Local intra-arterial infiltration thrombolysis successfully reconstituted flow through the main aortic segment and left iliac limb. With a combination of conventional surgical and intraoperative endovascular procedures, thrombectomy and recanalization of the right iliac limb was completed by stenting a severe stenosis of the proximal iliac limb.

Conclusions:

A combination of techniques may be essential for successful management of thrombotic complications after endovascular AAA repair.

Quality Control during Endovascular Aneurysm Repair: Monitoring Aneurysmal Sac Pressure and Superficial Femoral Artery Flow Velocity

Purpose:

To use intraoperative aneurysmal sac pressure measurement and flow monitoring of the superficial femoral artery (SFA) to ensure complete exclusion of the aneurysm from the circulation.

Methods:

A 5F catheter was positioned in the aneurysmal sac of 15 consecutive patients undergoing endovascular aortomonoiliac aneurysm repair between February and September 1997. The catheter was connected to an external pressure transducer allowing pressure monitoring throughout the operation and for 24 hours postprocedurally. Flow velocity was monitored in the contralateral SFA by insonation with a 2-MHz Doppler ultrasound probe.

Results:

No technical defect was observed in the deployment of 10 endografts, which demonstrated marked reduction in sac pressure and good flow in the lower limb. The mean aneurysm pressure dropped from 123 to 57 mmHg after graft insertion. In 5 cases, monitoring detected problems during the endograft procedure. In 3, incomplete stent deployment was detected by a failure of sac pressure to fall following stent inflation and by the presence of flow in the contralateral femoral artery. In the other 2 cases, a distal endoleak was detected by direct injection of contrast into the sac.

Conclusions:

Measuring aneurysm pressure in combination with SFA Doppler flow monitoring can detect complications of endovascular aneurysm repair.

Changes in Referral Practice, Workload, and Operative Mortality after Establishment of an Endovascular Abdominal Aortic Aneurysm Program

Purpose:

To determine the change in referral practice following establishment of an endovascular abdominal aortic aneurysm (AAA) program.

Methods:

A prospective audit of all elective admissions for AAA was established in January 1994 at the initiation of an endovascular AAA program. A comparison was made between this cohort and the elective AAA repairs performed between 1981 and 1993.

Results:

Since January 1994, 213 AAA patients (177 men; median age 73 years, range 54 to 88) have been referred for potential endovascular aneurysm repair. To date, 142 patients have undergone elective surgery (41 endovascular and 101 conventional). Between 1981 and 1993, 304 patients (255 men; median age 69 years, range 45 to 86) had elective aneurysm repair. Comparison of the two time periods has revealed significant increases in the number of tertiary referrals (41.8% versus 9.5%, p < 0.01), annual operations (50 versus 23, p < 0.05), and overall mortality (12% versus 6.7%, p < 0.05), the latter attended by a significant increase in cardiorespiratory comorbidity.

Conclusions:

The higher elective AAA mortality rate since the establishment of an endovascular program reflects a change in referral practice and may be directly attributable to an increase in the number of high-risk patients. An endovascular AAA program has clinical and financial implications for the hospital concerned.

Distal Peripheral Microembolism

Distal peripheral microembolism is caused by embolization of atherosclerotic debris into small arteries and arterioles. The recent advances in endovascular technique have been met with a gradual increase in the incidence of iatrogenic atheroembolism. This review seeks to explore the nature of distal peripheral microembolism, pathophysiology, and the management options, with a focus on iatrogenic distal peripheral microembolism.

Thromboembolic complications after endovascular aortic aneurysm repair

PURPOSE

To evaluate the frequency and significance of thromboembolic complications following endovascular treatment of aortic aneurysms.

METHODS

One hundred seventy-four patients (153 men; mean 71.4 years, range 26-90) underwent endovascular repair of aneurysms of the thoracic (n = 38) or abdominal (n = 136) aorta using a variety of endografts. All patients were examined preprocedurally using 3-phase helical computed tomography (CT) to determine appropriate endograft size. To exclude the occurrence of infarction in parenchymal organs, the first postprocedural CT scan was compared with preoperative findings. Newly recognized perfusion deficits were taken as evidence of procedure-related infarction.

RESULTS

Infarctions were detected in 16 (9.2%) patients: 13 in the kidneys, 2 in the spleen, with 1 in the mesentery; only the mesenteric infarction was clinically symptomatic. Both splenic infarctions were associated with deployment of stent-grafts in the thoracic aorta (5.3% of the 38 patients), while the mesenteric and 13 renal infarctions were seen in patients with infrarenal abdominal aortic aneurysms (0.7% and 9.6%, respectively, of 136 patients). One patient experienced complete thromboembolic occlusion of a renal artery, which was partially recanalized with intraoperative lysis.

CONCLUSIONS

Thromboembolic complications of endovascular aortic aneurysm repairs are not uncommon, and although usually asymptomatic, these sequelae have the potential to be life threatening. Perfusion abnormalities may respond to immediate lytic therapy with complete dissolution of the thrombus in certain isolated cases.

Renal infarction following endovascular aortic aneurysm repair: incidence and clinical consequences

PURPOSE

To investigate the incidence of renal infarction following endovascular abdominal aortic aneurysm (AAA) repair, with particular emphasis on a comparison of suprarenal versus infrarenal endograft placement.

METHODS

Ninety-nine patients (92 men; average age 68 years) who had undergone endovascular AAA repair between July 1995 and July 1999 and who had at least 12 months' follow-up were studied with spiral computed tomographic scans to identify suprarenal endograft deployment and renal infarction.

RESULTS

Among the 193 renal arteries available for study, partial or complete transrenal endograft placement was found in 69 (36%). Sixteen (8.3%) renal infarctions were identified by the postoperative imaging studies. Perfusion of these kidneys was supplied by 6 (8.7%) of the 69 overstented renal arteries and 7 (5.6%) of the 124 uncovered arteries (p > 0.05). In the 3 other cases, intentional accessory renal artery occlusion by the stent-graft fabric led to frank segmental renal infarctions, which were visualized as territorial-perfusion defects affecting up to 27% of the renal volume. In the other 13 infarcted kidneys, the punctate deficits involved <10% of the parenchymal volume. Renal retention values were unaffected in 15 (94%) of 16 patients.

CONCLUSIONS

Documented renal infarctions following endovascular aortic stent-graft placement are not common and do not appear to be associated with suprarenal endograft fixation.

Endovascular AAA repair attenuates the inflammatory and renal responses associated with conventional surgery

PURPOSE

To quantify the inflammatory and renal parameters in comparative cohorts of patients undergoing surgical or endovascular repair of abdominal aortic aneurysms (AAAs).

METHODS

Forty-three patients (41 men; ages 58-81 years) underwent endovascular or conventional aneurysm surgery according to aortic morphology. All patients received a standard general anesthetic and had 12 serial blood and urine samples collected during the perioperative period. Samples underwent analysis for the cytokines interleukin (IL) 1beta tumor necrosis factor-alpha (TNF-alpha), and IL-6. White cell and platelet activation were estimated indirectly by measuring sL-selectin and 11-dehydrothromboxane B2, respectively. The urinary albumin:creatinine ratio (ACR) and N-acetyl-beta-D-glucosaminidase (NAG) activity were estimated to assess renal injury. Fibrinogen and fibrinogen degradation products were calculated to assess activation of the clotting cascade.

RESULTS

Twenty-three patients underwent endovascular AAA repair and 20 had conventional surgery. Concentrations of IL-6 (p < 0.002) and TNF-alpha (p < 0.0004) were significantly higher in the conventional group. The ACR (p < 0.002) and urinary NAGs (p < 0.0009) were also significantly higher in this group, suggesting greater renal injury. Platelet activity was significantly greater in the endovascular group (p < 0.01), perhaps indicating thrombus organization within the aneurysm sac.

CONCLUSIONS

These data suggest that the inflammatory response associated with conventional aneurysm repair is largely obviated by endovascular techniques. This may potentially translate to a lower incidence of multiple organ failure after endovascular surgery.

Quality control during endovascular aneurysm repair: monitoring aneurysmal sac pressure and superficial femoral artery flow velocity

PURPOSE

To use intraoperative aneurysmal sac pressure measurement and flow monitoring of the superficial femoral artery (SFA) to ensure complete exclusion of the aneurysm from the circulation.

METHODS

A 5F catheter was positioned in the aneurysmal sac of 15 consecutive patients undergoing endovascular aortomonoiliac aneurysm repair between February and September 1997. The catheter was connected to an external pressure transducer allowing pressure monitoring throughout the operation and for 24 hours postprocedurally. Flow velocity was monitored in the contralateral SFA by insonation with a 2-MHz Doppler ultrasound probe.

RESULTS

No technical defect was observed in the deployment of 10 endografts, which demonstrated marked reduction in sac pressure and good flow in the lower limb. The mean aneurysm pressure dropped from 123 to 57 mmHg after graft insertion. In 5 cases, monitoring detected problems during the endograft procedure. In 3, incomplete stent deployment was detected by a failure of sac pressure to fall following stent inflation and by the presence of flow in the contralateral femoral artery. In the other 2 cases, a distal endoleak was detected by direct injection of contrast into the sac.

CONCLUSIONS

Measuring aneurysm pressure in combination with SFA Doppler flow monitoring can detect complications of endovascular aneurysm repair.