Stewart Kribs

Cumulative sum failure analysis of the learning curve with endovascular abdominal aortic aneurysm repair

PURPOSE The purpose of this study was to evaluate the importance of experience and the learning curve with endovascular abdominal aortic aneurysm (AAA) repair. METHODS A retrospective analysis was performed of all elective endovascular AAA repairs attempted by an individual surgeon and radiologist over a 4-year period. The primary outcome variable was achievement and 30-day maintenance of initial clinical success as defined by the Society for Vascular Surgery/American Association of Vascular Surgery reporting standards. Following standard statistical analysis, the cumulative sum (CUSUM) method was used to analyze the learning curve, with a predetermined acceptable failure rate of 10% and calculated 80% alert and 95% alarm lines. RESULTS Ninety-six elective endovascular AAA repairs were attempted by this team between 1998 and 2002 (mean age 74 +/- 0.8 years; mean aneurysm diameter 5.98 +/- 0.8 cm). Initial clinical success was achieved and maintained in 85 of 96 patients (88.5%). Although results were acceptable throughout the study period, improved results with respect to the target failure rate (10%) were not achieved until 60 patients were treated. The learning or CUSUM curves did not differ for different device manufacturers, with improved results being achieved following 20 implantations of each device. The results did differ when comparing aortouniiliac grafts (n = 27) and bifurcated grafts (n = 64). Results with bifurcated grafts remained consistent throughout the study period, whereas with aortouniiliac grafts, results improved after only a few procedures in comparison with the target failure rate. CONCLUSION Success rates with endovascular aneurysm repair will improve with an individuals experience. The CUSUM method is a valuable tool in the evaluation of this learning curve, which has credentialing and training implications. Although acceptable results were obtained throughout the study period, this analysis indicates that 60 endovascular aneurysm repairs, or 20 with an individual device, are necessary before optimal rates of initial clinical success can be achieved. These results can be achieved more readily with aortouniiliac grafts than with bifurcated grafts.

Hybrid Open and Endovascular Therapy for a Proximal Subclavian Artery Aneurysm

A 57-year-old male presented with a large proximal right subclavian artery aneurysm that had been the source of upper extremity emboli on two occasions. A combined open and endovascular approach was undertaken involving a common carotid to vertebral artery autogenous bypass via a supraclavicular incision and endovascular repair of the aneurysm from a transbrachial approach. The patient did well postoperatively and recovered fully following a short hospitalization.

Fibrinogen Level and Bleeding Risk During Catheter-Directed Thrombolysis Using Tissue Plasminogen Activator.

Purpose: The purpose of this study was to determine whether low fibrinogen levels (fibrinogen level <1.5 g/L) during catheter-directed thrombolysis are associated with an increased bleeding risk. Methods: A retrospective review was performed on patients undergoing extremity arterial or venous thrombolysis between 2005 and 2013. Results: Patients in the low fibrinogen group were younger (P = .006) and had a higher number of venous occlusive events (P = .004). The low fibrinogen group received a larger dose of tissue plasminogen activator (tPA; P = .009) and had a longer duration of thrombolysis (P = .010). The rates of major bleeding were not significantly different (P = .139). Univariate analysis showed that larger total dose and longer duration of tPA infusion were associated with increased bleeding complications (P < .01 and P = .03). Conclusion: A fibrinogen level <1.5 g/L during thrombolysis was not associated with an increased bleeding risk. However, larger dose and longer duration of thrombolysis were associated with increased bleeding risk.

Complementary roles of low-dose SPECT-CT and high-resolution volume CT for detection of coronary artery disease.

A 70-year-old woman with a high pretest likelihood of coronary artery disease (CAD) underwent a Tc-99m MIBI SPECT-CT study for myocardial perfusion imaging (MPI), which was complemented by a high-resolution volume CT (VCT) study. After attenuation correction, an MPI pattern of ischemia was detected in the lateral wall of the myocardium. The CT calcium score (CTCS) was above the 75th percentile. The CT angiography (CTA) demonstrated a 70% stenosis at the ostial part of the circumflex artery, and incidentally revealed a saccular aneurysm. In todays nuclear cardiology, low-dose SPECT-CT plus high-resolution VCT allows anatofunctional assessment of suspected CAD.

Strategies to reduce line infections in a small child with homozygous familial hypercholesterolaemia who cannot yet receive LDL apheresis

Patients with homozygous familial hypercholesterolaemia are optimally treated with low-density lipoprotein apheresis. Young patients who do not meet a weight threshold (25 kg) receive regular plasmapheresis. This approach may remove excessive immunoglobulins and vascular access set-up can be challenging. We report the case of a 4 year-old child who exhibited repeated septic infections (5 in 6 months) and had recurrent access issues before two interventions were implemented: (1) the percutaneous central venous line was modified to two implanted paediatric ports, and (2) the patient started receiving two bags of Octaplasma at the end of each plasmapheresis treatment to account for the excessive loss of immunoglobulins. For the paediatric plasmapheresis access port, a 19-gauge Huber needle had to be used for the arterial port to prevent the collapse of the extension. These two simple changes have left the patient infection-free for 9 months.

Surveillance and medical therapy following endovascular treatment of chronic cerebrospinal venous insufficiency.

The debate regarding the possible link between chronic cerebrospinal venous insufficiency and multiple sclerosis (MS) is continuously becoming more and more contentious due to the current lack of level 1 evidence from randomized trials. Regardless of this continued uncertainty surrounding the safety and efficacy of this therapy, MS patients from Canada, and other jurisdictions, are traveling abroad to receive central venous angioplasty and, unfortunately, some also receive venous stents. They often return home with few instructions regarding follow-up or medical therapy. In response we propose some interim, practical recommendations for post-procedural surveillance and medical therapy, until further information is available.