Kristofer M. Charlton-Ouw

Feasibility of simultaneous pre- and postfilter transcranial Doppler monitoring during carotid artery stenting

OBJECTIVE Carotid artery stenting (CAS) is emerging as an acceptable treatment alternative to surgery for patients with carotid artery stenosis. The major risk of CAS is cerebral embolization of plaque and thrombus causing stroke or asymptomatic brain infarction. Use of embolic protection devices (EPD) to trap emboli before they reach the brain is now standard practice in CAS. The pore size of the currently available filters is >100 microns and emboli smaller than the EPD pores can still reach the brain. While the use of EPD is widespread, little evidence exists of their in vivo efficacy in preventing distal embolization. Our aim was to quantify the number of emboli reaching the brain with the device in place. Therefore, the expected value of this report is in its description of a novel application of transcranial Doppler (TCD). Due to the limited number of cases, it is not intended to support the use of one EPD over another. METHODS Six patients were monitored with ipsilateral simultaneous dual probe TCD during CAS. Two types of cerebral protection systems were evaluated: FilterWire EZ System (FW; Boston Scientific, Santa Clara, Calif) and GORE Neuro Protection System (NPS; W.L. Gore and Associates, Flagstaff, Ariz). By placing TCD probes both proximal and distal to the filterwire EPD, we quantified the microembolic signals before the EPD as well as those, which reached the intracranial circulation after the EPD. One probe was placed submandibularly to monitor the ICA (SICA), while another was placed transtemporally to monitor the middle and anterior cerebral artery (MCA + ACA). We compare the number of extracranial emboli prior to the EPD with the number of intracranial emboli after the EPD. RESULTS Dual probe monitoring was successful during the five stages of the CAS: lesion crossing (LC), predilatation (PreD), stent placement (SP), postdilatation (PostD), and filter/device removal (FR/DR). Using FW during LC by probe 1 (SICA)/probe 2 (MCA + ACA): (18 [range, 15-22]/15 [range, 11-20]), PreD (111 [range, 101-121]/101 [range, 90-111]), SP (68 [range, 60-76]/42 [range, 30-53]), PostD (27 [range, 25-30]/24 [range, 22-27]), FR (0.3 [range, 0-1]/0.7 [range, 0-1]) average number of microembolic signals were detected. Using NPS during LC (1.7 [range, 0-3]/1 [range, 0-2]), PreD (0/1.7 [range, 0-4]), SP (0/0), PostD (0/0), DR (18 [range, 0-18]/6.7 [range, 1-13]) average number of microembolic signals were detected. CONCLUSION EPD significantly reduces but does not eliminate the number of microemboli reaching the brain during carotid artery angioplasty and stenting. We propose monitoring of CAS with submandibular and transtemporal TCD probes to further evaluate the practice of distal embolization protection. Although our study is not powered to make any recommendations about EPDs, we believe that sequential dual probe TCD monitoring is a worthy tool with the potential to give vital information to assess the various devices and the techniques of utilization.

Thoracic Endovascular Aortic Repair for Type B Aortic Dissection

BACKGROUND Thoracic endovascular aortic repair (TEVAR) has emerged as an acceptable off-label treatment modality for aortic dissection. We report our experience in endovascular treatment of this disease with an emphasis on defining the patterns of morbidity. METHODS We retrospectively reviewed all (n = 90) patients with thoracic aortic disease who received a TEVAR between February 2005 and December 2007. Aortic dissection was the indication in 23 (26%) patients (48% acute, 52% chronic; Stanford A 17%, Stanford B 83%). For the purposes of this report, we concentrated on the type B dissection (17 patients). Eighty-two percent of the patients were symptomatic on presentation, and 56% of cases were performed either urgently or emergently. RESULTS Technical success was achieved in 100% of cases, with an average operative time of 178 + or - 119 min. Forty-seven percent required a left subclavian bypass. Thirty-day mortality was 5.5% and morbidity was 12%. Postoperative complications included respiratory failure in 28% of cases, gastrointestinal symptoms in 11%, and cerebrovascular symptoms in 5.5%. No renal failure occurred. While cerebrospinal fluid drain was used in 35% of cases, transient spinal cord ischemia was observed in 5.5%. Average length of stay was 13 + or - 12 days; 63% of patients were discharged home, 12% required rehabilitation, and 25% were discharged to a skilled nursing facility. There was no association between outcome and mode of presentation or anatomic extent. CONCLUSION Aortic dissection remains a challenging clinical entity, and the advent of TEVAR has improved outcomes but still carries considerable morbidity, with distinct patterns between mode of presentation and anatomic extent.

Successful Emergency Endovascular Treatment for Superior Vena Cava Injury

Superior vena cava (SVC) hemorrhage due to iatrogenic injury is an infrequent but important event. We report the case of a 56-year-old woman with a history of right pneumonectomy for lung cancer with iatrogenic SVC injury and hemorrhage. After unsuccessful attempts at suture repair of the defect, an endovascular approach using a stent graft succeeded in controlling hemorrhage while maintaining vessel patency. To our knowledge, this is the third report of SVC hemorrhage control using this technique, and it supports the experience of other authors that endovascular stenting is an effective means of treating emergent venous hemorrhage.

Spontaneous regression of an abdominal aortic aneurysm in an immunocompromised patient.

Spontaneous aneurysmal regression is a rare event, having been observed only in association with arteritides or immunosuppression following solid-organ transplantation. In particular, the spontaneous regression of an aortic aneurysm, to our knowledge, has never been documented. We report a case of a 46-year-old, HIV-positive, African-American man who developed an asymptomatic juxtarenal abdominal aortic aneurysm, which significantly regressed over a 6-month period in the absence of arteritides or systemic immunosuppressive therapy. This case describes the spontaneous regression of an inflammatory AAA in an HIV-positive patient. Further studies will be required to determine if this was an isolated occurrence or if it occurs with any frequency in specific patient populations.