Clinical significance of incidentally detected lead perforations by computed tomography.

BACKGROUND: Computed tomography (CT) has an established role in detecting perforation of implanted pacemaker and defibrillator leads. The clinical significance of incidental finding of delayed lead perforation remains unclear. The aim of this study was to assess the prevalence of lead perforation as detected by CT in a cohort of patients undergoing transvenous laser lead extraction and characterize the association between finding of incidental lead perforation with periprocedural outcomes. METHODS: Consecutive patients that underwent chest CT and lead extraction were retrospectively assessed for presence of lead perforation. A total of 143 patients and 348 leads were assessed. The finding of lead perforation was correlated with findings from peri-procedural transesophageal echocardiography (TEE) and outcomes of the lead extraction procedure. RESULTS: Lead perforations (including perforations <5 mm and ≥5 mm) were detected in 66 (46%) patients and 73 (21%) leads. Lead perforation ≥5 mm were less common and detected in 13 (9%) of patients and 14 (4%) of leads. There was no significant difference in the rates of peri-procedural death, cardiac avulsion, cardiac tamponade or post-extraction pericardial effusion in patients with and without lead perforation. CONCLUSIONS: Incidental delayed lead perforations detected by CT are common and do not correlate with significant TEE findings or adverse peri-procedural outcomes in patients undergoing lead extraction. Larger studies are needed to further characterize the frequency and safety of these findings.

Highly Sensitive Cardiac Troponins: The Evidence Behind Sex-Specific Cutoffs.

Emergence of various highly sensitive cardiac troponin assays into clinical practice provides a new tool for clinicians diagnosing acute coronary syndrome. These assays also create a challenge for laboratories and clinicians who have yet to familiarize themselves with sex-specific cutoffs. Healthy men and women, studied across various age groups and geographic locations, have notable differences in baseline values of highly sensitive cardiac troponin I and T, leading to establishment of sex-specific upper reference limits and cutoffs. Several differences in cardiac physiology, size, and structure may account for baseline differences in highly sensitive cardiac troponins and outcomes between the sexes. The clinical utility of implementing sex-specific cutoffs for diagnosis and management of acute coronary syndrome remains unclear. Presently, the only prospective study failed to show improved outcomes for men or women with use of sex-specific cutoffs; however, a major limitation is the frequent lack of diagnostic, therapeutic, and preventive interventions prescribed to women with low-level troponin elevations. Based on the current literature, we posit that there may nonetheless be clinical value in the use of sex-specific cutoffs for evaluating suspected acute coronary syndrome, especially in select patient populations such as younger women who tend to have lower baseline values of highly sensitive cardiac troponins. Future studies should prospectively evaluate differences in diagnostic, pharmacologic, and interventional management in men and women using myocardial infarctions classified with sex-specific cutoffs of the highly sensitive cardiac troponin assays.

Prevalence and Short-Term Clinical Outcome of Mobile Thrombi Detected on Transvenous Leads in Patients Undergoing Lead Extraction.

OBJECTIVES: This study sought to prospectively evaluate the prevalence, risk factors, and short-term major clinical outcomes of mobile thrombus detected on transvenous leads in patients undergoing lead extraction. BACKGROUND: The prevalence and clinical significance of thrombus on transvenous leads in patients undergoing lead extraction is not well characterized. METHODS: Consecutive patients undergoing transvenous lead extraction for noninfectious indications were enrolled. Preoperative transesophageal echocardiograms were performed prospectively for all patients to examine for mobile thrombus. Anticoagulation was not started for thrombus unless other indications were present. Clinical endpoints of mortality and cardiovascular morbidity (symptomatic pulmonary embolism, myocardial infarction, or cerebrovascular accident) were assessed at a minimum of 2-month follow-up. RESULTS: A total of 108 patients underwent lead extraction for noninfectious indications. Lead thrombi were detected in 20 (18.5%) patients and all were <2 cm. Clinical and lead characteristics were not associated with formation of lead thrombi, except for younger patient age. In patients with detected thrombi, there were no short-term deaths, symptomatic pulmonary embolisms, or myocardial infarctions, except 1 patient with a stroke 3 months after lead extraction (7% vs. 5%; p = 1.00). Median follow-up was 9 months. CONCLUSIONS: Mobile thrombi on transvenous leads are commonly found in patients referred for transvenous lead extraction and are rarely associated with acute major adverse outcomes. Careful extraction of leads with small incidentally detected thrombi can likely be performed without major acute clinical sequelae. Larger studies with longer follow-up are needed to further assess the long-term clinical significance of lead thrombi.

Not Your Garden-Variety Bacteremia: Gardnerella in an Immunocompromised Man.

Systemic Gardnerella infections are rare and usually associated with surgical instrumentation of the genitourinary tract. We present a case of symptomatic and transient Gardnerella bacteremia in a man with AIDS after a traumatic urinary catheter insertion.

A Novel Preclinical Model of Moderate Primary Blast-Induced Traumatic Brain Injury.

Blast-induced traumatic brain injury (bTBI) is the "signature" injury of the recent Iraq and Afghanistan wars. Here, we present a novel method to induce bTBI using shock wave (SW) lithotripsy. Using a lithotripsy machine, Wistar rats (N = 70; 408.3 ± 93 g) received five SW pulses to the right side of the frontal cortex at 24 kV and a frequency of 60 Hz. Animals were then randomly divided into three study endpoints: 24 h (n = 25), 72 h (n = 19) and 168 h (n = 26). Neurological and behavioral assessments (Garcia's test, beam walking, Rotarod, and elevated plus maze) were performed at the baseline, and further assessments followed at 3, 6, 24, 72, and 168 h post-injury, if applicable. We performed digital subtraction angiography (DSA) to assess presence of cerebral vasospasm due to induced bTBI. Damage to brain tissue was assessed by an overall histological severity (OHS) score based on depth of injury, area of hemorrhage, and extent of axonal injury. Except for beam walking, OHS was significantly correlated with the other three outcome measures with at least one of their assessments during the first 6 h after the experiment. OHS manifested the highest absolute correlation coefficients with anxiety at the baseline and 6 h post-injury (r(baseline) = -0.75, r(6hrs) = 0.85; p<0.05). Median hemispheric differences for contrast peak values (obtained from DSA studies) for 24, 72, and 168 h endpoints were 3.45%, 3.05% and 0.2%, respectively, with statistically significant differences at 1 versus 7 d (p<0.05) and 3 versus 7 d (p<0.01). In this study, we successfully established a preclinical rat model of bTBI with characteristics similar to those observed in clinical cases. This new method may be useful for future investigations aimed at understanding bTBI pathophysiology.

Elevated blood pressure causes larger hematoma in a rat model of intracerebral hemorrhage.

Hypertension has been recognized as an independent risk factor for intracerebral hemorrhage (ICH). The objective of this study was to assess the effect of chronically elevated blood pressure on amount of hematoma in a rat model of ICH. A total of 46 rats were divided into two groups-normotensive group (n = 18) and spontaneously hypertensive group (n = 28). To induce ICH, we delivered 2 µL of collagenase solution (0.1 U/1 µL normal saline) into the striatum. Each animal's brain was removed 24 h post-surgery for spectrophotometric hemoglobin assay. Equal or unequal variance t tests were performed to assess changes in variables between the hypertensive and normotensive groups. Tissue analysis revealed a statistically significant difference in optical density percent change at 540-nm wavelength for the hypertensive vs. the normotensive group (261.47 ± 103.68 and 133.33 ± 58.53, p < 0.0001, respectively). As compared to the normotensive rats, hypertensive rats exhibited a higher neurological deficit, loss of balance and coordination, and loss of motor function. Our results demonstrated that hypertensive rats had significantly higher amounts of hemorrhage in comparison to normotensive ones. These findings support the need for further adequately powered studies to investigate differences in amount of hematoma and corresponding functional impairments due to ICH among hypertensive vs. normotensive rats.