Observer Variability of Iliac Artery Measurements in Endovascular Repair of Abdominal Aortic Aneurysms

Accurate measurement of iliac arteries is essential for successful delivery of aortic endografts without iliac limb endoleak. Although intravascular ultrasound measurements may be reliable, they require an invasive procedure. Therefore, helical computed tomography (hCT) has become the most commonly used modality for obtaining preprocedure arterial diameter measurements. The accuracy of hCT remains ill-defined, however, because an anatomic gold standard with which to compare the measurements is not available. We therefore assessed inter- and intraobserver variability of hCT measurements. We also applied accepted cutoff measurements to determine the clinical impact of observer variability in predicting the need for adjunctive iliac access and iliac limb seal procedures. hCT scans were analyzed in 30 patients who had undergone successful placement of a bifurcated endograft (26 Ancure, 4 Aneurex). Mean age of patients was 75 years, the male/female ratio was 27:3. Three blinded observers measured transverse diameters (maximal aortic aneurysm [Amax], narrowest infrarenal aortic neck [Amin], maximal common iliac [Imax], and narrowest iliac artery [Imin]). Inter- and intraobserver variability was calculated as standard deviation of mean pair differences according to the method of Bland and Altman. The true incidence of adjunctive procedures to facilitate delivery of the device into the aorta and ensure iliac limb seal was compared with that predicted by the observers to obtain sensitivity, specificity, and positive (PPV) and negative predictive value (NPV) for the measurements. Interobserver variability of iliac measurements was higher than intraobserver variability (p < 0.05). Interobserver variability of Amax ranged from 4.37 to 10.73% of the mean Amax. Conversely, variability of Amin was 8.91-18.89%, that of Imax was 12.11-22.23%, and that of Imin was 10.51-18.73% (p < 0.05 vs. Amax). Therefore, interobserver variability influenced aortic neck and iliac diameter twice as much as it did aneurysm measurements. To successfully place 30 endografts we performed 8 adjunctive access procedures (4 angioplasties, 4 common iliac artery conduits) and 17 adjunctive procedures in 60 limbs to ensure limb seal (9 unilateral IIA coil embolizations, 8 stents). We used 8.5 (Ancure) and 8.0 (Aneurex) mm as lower limits of acceptability for uncomplicated access, and 13.4 (Ancure) and 16 (Aneurex) mm as the upper limits of acceptability for uncomplicated iliac limb seal. These limits were applied to measurements from the three observers to predict need for adjunctive access or iliac seal procedures in this cohort. Sensitivity, specificity, PPV, and NPV of these observer measurements for a need to perform additional access procedures were 0.67, 0.80, 0.55, and 0.87; the same values for a need to perform additional seal procedures were 0.71, 0.74, 0.52, and 0.86, respectively. Interobserver variability was approximately 20% of measured iliac diameter. This explains why helical CT measurements were noted to have low PPV in predicting the need for an adjunctive access or limb seal procedure. These data establish PPV and NPV for hCT and provide objective evidence for the need to improve iliac artery imaging. Until more accurate imaging becomes available, we recommend oversizing of iliac limbs by 10-20% in patients with wide landing zones and that surgeons be prepared to resolve unexpected iliac artery access or seal problems intraoperatively.Presented at the 13th Annual Winter Meeting of the Peripheral Vascular Surgery Society, Steamboat Springs, CO, January 31-February 2, 2004.     

COVID-19 vaccine effectiveness by HIV status and history of injection drug use: a test-negative analysis

Introduction

People living with HIV (PLWH) and/or who inject drugs may experience lower vaccine effectiveness (VE) against SARS-CoV-2 infection.

Methods

A validated algorithm was applied to population-based, linked administrative datasets in the British Columbia COVID-19 Cohort (BCC19C) to ascertain HIV status and create a population of PLWH and matched HIV-negative individuals. The study population was limited to individuals who received an RT-PCR laboratory test for SARS-CoV-2 between 15 December 2020 and 21 November 2021 in BC, Canada. Any history of injection drug use (IDU) was ascertained using a validated administrative algorithm. We used a test-negative study design (modified case−control analysis) and multivariable logistic regression to estimate adjusted VE by HIV status and history of IDU.

Results

Our analysis included 2700 PLWH and a matched population of 375,043 HIV-negative individuals, among whom there were 351 and 103,049 SARS-CoV-2 cases, respectively. The proportion of people with IDU history was much higher among PLWH compared to HIV-negative individuals (40.7% vs. 4.3%). Overall VE during the first 6 months after second dose was lower among PLWH with IDU history (65.8%, 95% CI = 43.5–79.3) than PLWH with no IDU history (80.3%, 95% CI = 62.7–89.6), and VE was particularly low at 4–6 months (42.4%, 95% CI = −17.8 to 71.8 with IDU history vs. 64.0%; 95% CI = 15.7–84.7 without), although confidence intervals were wide. In contrast, overall VE was 88.6% (95% CI = 88.2–89.0) in the matched HIV-negative population with no history of IDU and remained relatively high at 4–6 months after second dose (84.6%, 95% CI = 83.8–85.4). Despite different patterns of vaccine protection by HIV status and IDU history, peak estimates were similar (≥88%) across all populations.

Conclusions

PLWH with a history of IDU may experience lower VE against COVID-19 infection, although findings were limited by a small sample size. The lower VE at 4–6 months may have implications for booster dose prioritization for PLWH and people who inject drugs. The immunocompromising effect of HIV, substance use and/or co-occurring comorbidities may partly explain these findings.     

CT imaging features and frequency of left ventricular myocardial fat in patients with CT findings of chronic left ventricular myocardial infarction

AIM: To determine the frequency of left ventricular myocardial fat in patients with computed tomography (CT) findings of chronic left ventricular myocardial infarction, and to review the typical CT imaging features. MATERIALS AND METHODS: A retrospective search of the CT and nuclear scintigraphy reports from 1998-2005 for chronic left ventricular myocardial infarction was performed. The study group comprised those cases with available CT examinations revealing findings of chronic left ventricular myocardial infarction. Assessment for the presence of various imaging characteristics of left ventricular myocardial fat was performed in all cases. RESULTS: The frequency of left ventricular myocardial fat in 47 patients with CT evidence of chronic left ventricular myocardial infarction was 51%. Typical CT imaging features include thin linear or curvilinear fat attenuation within left ventricular myocardium, most commonly subendocardial, often associated with left ventricular wall thinning and/or calcification, predominantly in elderly men. CONCLUSIONS: Fat in the left ventricular myocardium is a common additional finding in patients with CT findings of chronic left ventricular myocardial infarction. The potential, but as yet unproven, use of this CT imaging finding is that the radiologist may be able to suggest a potential diagnosis of chronic left ventricular myocardial infarction on unenhanced, thick-section, non-gated or non-triggered chest CT imaging where identification of myocardial wall thinning may be difficult.     

In-stent recurrent stenosis after carotid artery stenting: life table analysis and clinical relevance

OBJECTIVES: Carotid artery stenting has been proposed as an alternative to carotid endarterectomy in cerebral revascularization. Although early results from several centers have been encouraging, concerns remain regarding long-term durability of carotid artery stenting. We report the incidence, characteristics, and management of in-stent recurrent stenosis after long-term follow-up of carotid artery stenting. METHODS: Carotid artery stenting (n = 122) was performed in 118 patients between September 1996 and March 2003. Indications included recurrent stenosis after previous carotid endarterectomy (66%), primary lesions in patients at high-risk (29%), and previous ipsilateral cervical radiation therapy (5%). Fifty-five percent of patients had asymptomatic stenosis; 45% had symptomatic lesions. Each patient was followed up with serial duplex ultrasound scanning. Selective angiography and repeat intervention were performed when duplex ultrasound scans demonstrated 80% or greater in-stent recurrent stenosis. Data were prospectively recorded, and were statistically analyzed with the Kaplan-Meier method and log-rank test. RESULTS: Carotid artery stenting was performed successfully in all cases, with the WallStent or Acculink carotid stent. Thirty-day stroke and death rate was 3.3%, attributable to retinal infarction (n = 1), hemispheric stroke (n = 1), and death (n = 2). Over follow-up of 1 to 74 months (mean, 18.8 months), 22 patients had in-stent recurrent stenosis (40%-59%, n = 11; 60%-79%, n = 6; > or =80%, n = 5), which occurred within 18 months of carotid artery stenting in 13 patients (60%). None of the patients with in-stent recurrent stenosis exhibited neurologic symptoms. Life table analysis and Kaplan-Meier curves predicted cumulative in-stent recurrent stenosis 80% or greater in 6.4% of patients at 60 months. Three of five in-stent recurrent stenoses occurred within 15 months of carotid artery stenting, and one each occurred at 20 and 47 months, respectively. Repeat angioplasty was performed once in 3 patients and three times in 1 patient, and repeat stenting in 1 patient, without complications. One of these patients demonstrated asymptomatic internal carotid artery occlusion 1 year after repeat intervention. CONCLUSIONS: Carotid artery stenting can be performed with a low incidence of periprocedural complications. The cumulative incidence of clinically significant in-stent recurrent stenosis (> or =80%) over 5 years is low (6.4%). In-stent restenosis was not associated with neurologic symptoms in the 5 patients noted in this cohort. Most instances of in-stent recurrent stenosis occur early after carotid artery stenting, and can be managed successfully with endovascular techniques.     

Caspase-3 gene deletion prolongs survival in polycystic kidney disease

Pan-caspase inhibition reduces tubular apoptosis and proliferation and slows progression of disease in a rat model of polycystic kidney disease (PKD). It is unknown, however, which specific caspases are involved in PKD progression. Because caspase-3 is a major mediator of apoptosis, its role in autosomal recessive PKD was determined. Mice with caspase-3 gene deletion were crossed with mice harboring the congenital polycystic kidney (cpk) mutation to generate double-mutant mice. cpk;casp3^−/− mice lived nearly 4 times longer than littermate control cpk mice (mean survival of 117 d versus 32 d, P < 0.01), and cpk;casp3^+/− mice lived slightly longer than controls (mean survival of 56 d). In addition, the kidney weight, relative to body weight, was significantly lower in the cpk;casp3^−/− mice than in the cpk and cpk;casp3^+/− mice. Despite deletion of caspase-3, however, apoptosis occurred and cysts formed; therefore, the alternative pathways of apoptosis in cystic kidneys were investigated. Caspase-7 was up-regulated and the anti-apoptotic protein Bcl-2 was down-regulated in cpk, cpk;casp3^+/−, and cpk;casp3^−/− mice compared with wild-type controls. In summary, homozygous deletion of caspase-3 markedly prolongs survival of cpk mice, but a caspase-7-mediated pathway may compensate for the deficiency of functional caspase-3. These findings suggest that pan-caspase inhibition may have a greater therapeutic effect than selective caspase inhibition in PKD.Inherited polycystic kidney disease (PKD) is one of the leading causes of end-stage kidney disease requiring dialysis and kidney transplantation in children and adults.¹ Inherited PKD includes both autosomal dominant and autosomal recessive forms. Autosomal dominant polycystic kidney disease (ADPKD) results from mutations in one of two genes, PKD1 or PKD2. The prevalence of ADPKD varies between 1 in 400 and 1 in 1000, thus making it one of the most common hereditary diseases in the United States. ADPKD progresses to end-stage renal disease (ESRD) over a period of decades in 50% to 75% of affected people. Autosomal recessive polycystic kidney disease (ARPKD) results from a mutation in a single gene, PKHD1. ARPKD is less common, affecting about 1 in 20,000 live births and results in ESRD in childhood.²The congenital polycystic kidney (cpk) mouse is the most extensively characterized mouse model of PKD.² The inheritance, cyst localization in the kidney, and severity of kidney disease in the cpk mouse resembles ARPKD. Cys1, the cpk gene, encodes a cilia-associated protein called cystin that is disrupted in the cpk mouse.³ Increased apoptosis in polycystic kidneys has been described in cpk mice^4–8 as well as in human and other rat and mouse models of PKD.⁹ In support of a deleterious effect of apoptosis in PKD, we have recently demonstrated that pan-caspase inhibition reduces tubular apoptosis and proliferation and slows disease progression in the Han:SPRD rat model of PKD.¹⁰ The effect of caspase or apoptosis inhibition in other rat and mouse models of PKD is not known. Caspase-3 is the major mediator of apoptosis (i.e., the so-called “executioner” caspase) and caspase-1 is a pro-inflammatory caspase. However, the effect of inhibition of a specific caspase on PKD is not known. We tested the hypothesis that specific inhibition of caspase-3 would prolong life and reduce cyst formation in PKD.In the present study, we developed cpk mice that were either heterozygous or homozygous for caspase-3 deletion to determine the effect of specific caspase-3 deletion on the development of PKD.     

Superficial chemical peeling with salicylic Acid in facial dermatoses

Objective: To determine the effectiveness of salicylic acid chemical peeling in common dermatological conditions affecting face in people with predominant Fitzpatrick skin type IV and V. Design: An interventional, quasi-experimental study. Place and Duration of Study: Military Hospital, Rawalpindi and PAF Hospital, Sargodha, from July 2002 to June 2003. Patients and Methods: A total of 167 patients of either gender, aged between 13 to 60 years, having some facial dermatoses (melasma, acne vulgaris, postinflammatory hyperpigmentations, freckles, fine lines and wrinkles, post-inflammatory scars, actinic keratoses, and plane facial warts) were included. A series of eight weekly hospital based peeling sessions was conducted in all patients under standardized conditions with 30% salicylic acid. Clinical improvement in different disorders was evaluated by change in MASI score, decrease in the size of affected area and % reduction in lesions count. McNemar test was applied for data analysis. Results: Majority of the patients showed moderate to excellent response. There was 35% to 63% improvement (p<0.05) in all dermatoses. Significant side effects, as feared in Asian skins were not observed. Conclusion: Chemical peeling with salicylic acid is an effective and safe treatment modality in many superficial facial dermatoses.     

Kidney Transplantation and COVID-19: Two Case Reports

Immunocompromised populations are at great risk of the current 2020 global emergency of coronavirus disease 2019 (COVID-19), and treatment of kidney transplant recipients with COVID-19 is currently not declared. Hence, the purpose of the study is to set a clear treatment regimen. We report here a therapeutic course of 2 patients who underwent transplant surgery in March 2020 and got infected soon after. Since the transplant, these 2 patients have received triple maintenance immunosuppressive therapy with oral tacrolimus, mycophenolate mofetil (MMF), and prednisone, and they have been regularly followed up at our hospital. The tacrolimus trough level was between 10 and 12 ng/mL. After the diagnosis of COVID-19, MMF was stopped and the tacrolimus dose was reduced so that blood level was between 4 and 6 ng/mL. The first patient was a 30-year-old man who, despite being treated with hydroxychloroquine, favipiravir, oseltamivir, and azithromycin therapy, died because of the presence of other comorbidities. The second case was a 58-year-old man who fully recovered from COVID-19 pneumonia with treatment with methylprednisolone, MMF, azithromycin, favipiravir, hydroxychloroquine, and reduction in immunosuppression dosage. This reflects the importance of using glucocorticoids in the treatment of COVID-19 along with other medications and the decreased mortality rate associated with their use.