Whole-Heart Histological and Electroanatomic Assessment of Postinfarction Cardiac Magnetic Resonance Imaging Scar and Conducting Channels.

BACKGROUND: Cardiac magnetic resonance imaging (CMR)-defined ventricular scar and anatomic conduction channels (CMR-CCs) offer promise in delineating ventricular tachycardia substrate. No studies have validated channels with coregistered histology, nor have they ascertained the histological characteristics of deceleration zones (DZs) within these channels. We aimed to validate CMR scar and CMR-CCs with whole-heart histology and electroanatomic mapping in a postinfarction model. METHODS: Five sheep underwent anteroseptal infarction. CMR (116±20 days post infarct) was postprocessed using ADAS-3D, varying pixel intensity thresholds (5545, 6040, 6535, and 7030). DZs were identified by electroanatomic mapping (129±12 days post infarct). Explanted hearts were sectioned and stained with Picrosirius red, and whole-heart histopathologic shells were generated. Scar topography as well as percentage fibrosis, adiposity, and remaining viable myocardium within 3 mm histological biopsies and within CMR-CCs were determined. RESULTS: Using the standard 6040 thresholding, CMR had 83.8% accuracy for identifying histological scar in the endocardium (κ, 0.666) and 61.4% in the epicardium (κ, 0.276). Thirty-seven CMR-CCs were identified by varying thresholding; 23 (62%) were unique. DZs colocalized to 19 of 23 (83%) CMR-CCs. Twenty (87%) CMR-CCs were histologically confirmed. Within-channel histological fibrosis did not differ by the presence of DZs (P=0.242). Within-channel histological adiposity was significantly higher at sites with versus without DZs (24.1% versus 8.3%; P<0.001). CONCLUSIONS: Postprocessed CMR-derived scars and channels were validated by histology and electroanatomic mapping. Regions of CMR-CCs at sites of DZs had higher adiposity but similar fibrosis than regions without DZs, suggesting that lipomatous metaplasia may contribute to arrhythmogenicity of postinfarction scar.

5-Year Follow-Up of a Physician Performance Feedback Report Intervention to Reduce Overuse and Excess Cost: A National Cohort Study.

BACKGROUND: Mohs micrographic surgery efficiently treats skin cancer through staged resection, but surgeons' varying resection rates may lead to higher medical costs. OBJECTIVE: To evaluate the cost savings associated with a quality improvement. MATERIALS AND METHODS: The authors conducted a retrospective cohort study using 100% Medicare fee-for-service claims data to identify the change of mean stages per case for head/neck (HN) and trunk/extremity (TE) lesions before and after the quality improvement intervention from 2016 to 2021. They evaluated surgeon-level change in mean stages per case between the intervention and control groups, as well as the cost savings to Medicare over the same time period. RESULTS: A total of 2,014 surgeons performed Mohs procedures on HN lesions. Among outlier surgeons who were notified, 31 surgeons (94%) for HN and 24 surgeons (89%) for TE reduced their mean stages per case with a median reduction of 0.16 and 0.21 stages, respectively. Reductions were also observed among outlier surgeons who were not notified, reducing their mean stages per case by 0.1 and 0.15 stages, respectively. The associated total 5-year savings after the intervention was 92 million USD. CONCLUSION: The implementation of this physician-led benchmarking model was associated with broad reductions of physician utilization and significant cost savings.

Mortality after catheter ablation of structural heart disease related ventricular tachycardia.

BACKGROUND: There is a paucity of data describing mortality after catheter ablation of ventricular tachycardia (VT). OBJECTIVES: We describe the causes and predictors of cardiac transplant and/or mortality following catheter ablation of structural heart disease (SHD) related VT. METHODS: Over 10-years, 175 SHD patients underwent VT ablation. Clinical characteristics, and outcomes, were compared between patients undergoing transplant and/or dying and those surviving. RESULTS: During 2.8 (IQR 1.9-5.0) years follow-up, 37/175 (21%) patients underwent transplant and/or died following VT ablation. Prior to ablation, these patients were older (70.3 ± 11.1 vs. 62.1 ± 13.9 years, P = 0.001), had lower left ventricular ejection fraction ([LVEF] 30 ± 12% vs. 44 ± 14%, P < 0.001), and were more likely to have failed amiodarone (57% vs. 39%, P = 0.050), compared to those that survived. Predictors of transplant and/or mortality included LVEF≤35% (HR 4.71 [95% CI 2.18-10.18], P < 0.001), age ≥ 65 years (HR 2.18 [95% CI 1.01-4.73], P = 0.047), renal impairment (HR 3.73 [95% CI 1.80-7.74], P < 0.001), amiodarone failure (HR 2.67 [95% CI 1.27-5.63], P = 0.010) and malignancy (HR 3.09 [95% CI 1.03-9.26], P = 0.043). Ventricular arrhythmia free survival at 6-months was lower in the transplant and/or deceased, compared to non-deceased group (62% vs. 78%, P = 0.010), but was not independently associated with transplant and/or mortality. The risk score, MORTALITIES-VA, accurately predicted transplant and/or mortality (AUC: 0.872 [95% CI 0.810-0.934]). CONCLUSIONS: Cardiac transplant and/or mortality after VT ablation occurred in 21% of patients. Independent predictors included LVEF≤35%, age ≥ 65 years, renal impairment, malignancy, and amiodarone failure. The MORTALITIES-VA score may identify patients at high-risk of transplant and/or dying after VT ablation.

Clinical, electroanatomic and electrophysiologic characterization and outcomes of catheter ablation for ventricular tachycardia following valvular intervention.

INTRODUCTION: Ventricular tachycardia (VT) can occur following valvular interventions. There are limited data describing substrate and ablation approaches in such patients. We sought to describe the clinical, electrophysiologic, electroanatomic features and catheter ablation outcomes of patients with VT following aortic and/or mitral valve intervention. METHODS: Over 12-years, consecutive patients with aortic valve replacement (AVR) and/or mitral valve replacement (MVR) or repair, undergoing VT ablation, were identified from two centers. Clinical and procedural parameters and outcomes are described. RESULTS: Twenty-three patients (age 66 ± 14years, 78% male, left ventricular ejection fraction 37 ± 16%), with prior AVR (mechanical n = 6, bioprosthetic n = 2, transcatheter n = 1), MVR (mechanical n = 5, bioprosthetic n = 1), mitral valve repair (n = 6) and both mechanical AVR and MVR (n = 2), underwent VT ablation. Sixteen had concurrent ischemic cardiomyopathy, 10 with prior bypass surgery. Left ventricular access was obtained in 21/23 (91%) patients (transseptal n = 14, retrograde aortic n = 5, transapical n = 2), with perivalvular scar identified in 17/21 (81%). Re-entrant VT isthmi involved the perivalvular regions in 12/23 (52%) patients, and regions remote from the valve in the remainder; 9% had nonscar-related VT. Intramural substrate was ablated from adjacent chambers in 5/23 (22%) patients and with half-normal saline irrigation in 8/23 (35%) patients. There were no instances of catheter entrapment. Following final ablation, VA-free survival was 78% at 13-months. CONCLUSION: Only half of VT circuits following valvular interventions involve the valve regions themselves, while the remainder involves unrelated regions. Catheter ablation is safe and efficacious at treating VT following valvular intervention, but novel strategies may be required.

Hyaluronic Acid Filler Incidentally Found During Mohs Micrographic Surgery: Observations in 36 Patients Regarding Skin Depth, Degradation Size, and Estimated Persistence Time.

BACKGROUND: Although its clinical effect is reported to last up to 2 years, how long hyaluronic acid filler (HAF) histologically persists in the skin is unknown. OBJECTIVE: To determine the approximate persistence time of HAF in the skin and to correlate persistence time with HAF histological appearance, size, depth, and location. METHODS: Retrospective review of patient data and available frozen sections from 2003 to 2021 in which HAF was identified in 36 Mohs micrographic surgery patients. RESULTS: Incidental HAF histologically persisted in the skin for as long as 10.75 years in 1 patient and 3 years or more in 36.8% (7/19) of the patients who remembered the time of implantation. HAF is more apparent in frozen sections stained with toluidine blue than those stained with hematoxylin and eosin. Although HAF volume tended to be less with time, fragmentation was present both early at 3 months and at 3 years or more. There was no correlation of persistence time with anatomic location or depth. In 90.3% of the cases (28/31), HAF was located in the subcutaneous fat. There was no granulomatous or giant cell response at any time period. CONCLUSION: Hyaluronic acid filler may be seen histopathologically in the skin, usually in the subcutaneous fat, up to 10.75 years after implantation.

Isotretinoin in the treatment of hidradenitis suppurativa: a retrospective study.

OBJECTIVE: Isotretinoin has been used off-label in hidradenitis suppurativa (HS) patients with variable results, making it difficult to predict which patients with HS are likely to benefit. MATERIAL AND METHODS: We conducted a retrospective review of HS patients who presented to UCLA HS clinic between August 2009 and March 2018 and collected data on their demographics, reported history of isotretinoin treatment for HS, and treatment response. A number of patient variables were analyzed between the responders and non-responders to see if any were associated with a higher likelihood of a beneficial response. RESULTS: Of the 209 patients, 39 (18.7%) reported prior treatment with isotretinoin. A beneficial response to isotretinoin was reported by 14 (35.9%) patients, while 25 (64.1%) patients reported no response. When comparing responders to non-responders, responders were more likely to have a history of pilonidal cyst (p = .024). Having a concomitant history of regular or cystic acne did not appear to enhance HS treatment response to isotretinoin. CONCLUSIONS: Our data suggest that for HS patients, having a history of pilonidal cyst is associated with a beneficial response to isotretinoin.

Correlation of Suture Diameter With Its Ability to Cut Through an Artificial Skin Model.

BACKGROUND: Sutures can tear through tissue, but little data exist on the relative ability of different suture gauges and suture types to cut into the skin. OBJECTIVE: To quantify the relative ability of various sutures to cut into and tear through the skin. METHODS AND MATERIALS: We tested 4 suture types (polypropylene, nylon, polyglactin 910, and poliglecaprone 25) at 2 gauges each (3-0 and 5-0) in their ability to cut into and tear through an artificial skin substitute comprised of a 1-mm thick silicone sheet. The force required to cut into and through the skin substitute was measured using a digital force gauge that generated a force-time curve. The suture diameters were verified using both a precision caliper micrometer and an eyepiece micrometer with the microscope. Statistical analysis was performed using the Student t-test and analysis of variance. RESULTS: All 5-0 suture types required less force to cut into and tear through the skin substitute than their 3-0 counterparts. Among each suture gauge, there was no significant difference in tear-through force regardless of the suture type. CONCLUSION: Compared with larger gauge sutures, smaller gauge sutures more easily cut into and tear through skin substitute.

Irradiated Skeletal Muscle Cells Mimicking Those of Atypical Fibroxanthoma on Mohs Frozen Sections.

ABSTRACT: Radiation can induce changes to skeletal muscle cells that may mimic and thus be confused with cells of atypical fibroxanthoma (AFX), pleomorphic dermal sarcoma, spindle cell squamous cell carcinoma, and other spindle soft-tissue tumors. An 80-year-old White man presented for Mohs micrographic surgery of an AFX on the left lateral neck. The medical history was notable for a tongue squamous cell carcinoma 9 years before that had been treated with wide local excision, left neck dissection, and radiation to the oral cavity and left neck. Frozen sections from the first stage of Mohs did not show typical AFX, but did reveal patchy clusters of atypical spindled and epithelioid cells, some with multiple nuclei. Because of the unusual appearance of these cells, Mohs micrographic surgery was halted, and the frozen tissue block was sent for permanent pathology examination. The cells on permanent sections stained positive for desmin, revealing them to be of skeletal muscle origin (in this case damaged platysma muscle because of late postradiation changes). It is thus important for the Mohs surgeon and the consultant dermatopathologist to be aware of the unusual histologic appearance of irradiated skeletal muscle to avoid confusion with other spindle cell tumors.

Assessment of Materials to Prevent Sutures Cutting Through Atrophic Skin.

BACKGROUND: Sutures can tear through thin skin, especially in the elderly. To reinforce thin skin, several materials have been suggested through which sutures may be placed. OBJECTIVE: To evaluate the relative tear-through resistance to suture provided by various materials applied to a skin substitute. MATERIALS/METHODS: We measured the force needed for 3-0 polypropylene suture to tear through an artificial skin substitute, both alone and after various materials were applied. These materials included wound closure tapes, nonwoven polyester tape, hydrocolloid dressing, polyethylene film, and cyanoacrylate glue. The Student t-test and one-way analysis of variance were used to determine differences in the mean forces. RESULTS: Reinforced wound closure tape and nonwoven polyester tape were superior to the other materials, and provided a 3.1-fold and 3.6-fold increase in tear-through resistance, respectively, compared with skin substitute alone (p < .001). Orientation of wound closure tape and nonwoven polyester tape with their reinforcing fibers placed parallel to the skin substitute edge provided increased tear-through resistance compared with perpendicular placement. Affixing these latter materials with liquid adhesive also improved holding strength. CONCLUSION: Reinforced wound closure tape and nonwoven polyester tape, when applied to a skin substitute, provide significantly increased tear-through resistance to suture compared with skin substitute alone.

Fractal Deposits of a Hemostatic Hydrophilic Polymer in Mohs Micrographic Surgery Frozen Sections: A Histologic Analysis and Comparison With Sodium Polystyrene Sulfonate (Kayexalate).

Hydrophilic polymer with potassium ferrate (HPPF) powder is available as an over-the-counter hemostatic agent used by patients to stop superficial bleeding. In dermatology, it is applied to stop bleeding after superficial shave or punch biopsies or in open wounds after Mohs micrographic surgery. Despite its widespread availability, however, HPPF in histopathologic skin sections is highly unusual. We noted HPPF in skin closely resembles sodium polystyrene sulfonate (SPS) seen in colonic necrosis; SPS is a potassium binder given orally or rectally in hyperkalemic patients with end-stage renal disease. We describe the in vivo and in vitro histologic appearance of HPPF, compare HPPF with SPS, and discuss its potential migration into blood or lymph vessels.