Research Spotlight

Broyles, J. M., E. C. Liao, J. Kim, J. Heistein, M. Sisco, N. Karp, F. H. Lau and Y. S. Chun (2021). “Acellular Dermal Matrix-Associated Complications in Implant-Based Breast Reconstruction: A Multicenter, Prospective, Randomized Controlled Clinical Trial Comparing Two Human Tissues.” Plast Reconstr Surg 148(3): 493-500.

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BACKGROUND: Implant-based breast reconstruction accounts for the vast majority of breast reconstruction procedures and is commonly performed with human acellular dermal matrix. There is no consensus as to the optimal human acellular dermal matrix preparation, and high-quality evidence concerning comparative effectiveness is lacking. This study is the first prospective, multicenter, randomized controlled clinical trial to compare human acellular dermal matrix-related complications of the two most commonly used human acellular dermal matrices in implant-based breast reconstruction. The authors hypothesize that there will be no difference in infection, seroma, and reconstructive failure between FlexHD Pliable and AlloDerm RTU. METHODS: The authors conducted a Level 1 prospective, randomized, controlled, multicenter clinical trial to assess complications associated with the use of two human acellular dermal matrices in immediate postmastectomy implant-based breast reconstruction across seven clinical sites. Group A patients received FlexHD Pliable (113 patients with 187 breast reconstructions), and group B patients received AlloDerm RTU (117 patients with 197 breast reconstructions). RESULTS: There was no significant difference with respect to patient demographics, indications, comorbidities, and reconstruction approach between groups. Mean follow-up time was 10.7 ± 3.2 months. There was no statistical difference in the overall matrix-related complications between groups A and B (4.3 percent versus 7.1 percent, p = 0.233). Obesity (OR, 1.14; 95 percent CI, 1.05 to 1.24; p = 0.001) and prepectoral placement of matrix (OR, 4.53; 95 percent CI, 1.82 to 11.3; p = 0.001) were independently associated with greater risks of overall matrix-related complications. CONCLUSION: This work supports the use of human acellular dermal matrices in implant-based breast reconstruction and demonstrates no significant difference in matrix-related complication rates between FlexHD Pliable and AlloDerm RTU. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, I.

Zhang, Y., J. Cao, J. Zhou, C. Zhang, Q. Li, S. Chen, S. Feinstein, P. A. Grayburn and P. Huang (2021). “Plaque Elasticity and Intraplaque Neovascularisation on Carotid Artery Ultrasound: A Comparative Histological Study.” Eur J Vasc Endovasc Surg 62(3): 358-366.

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OBJECTIVE: Plaque elasticity and intraplaque neovascularisation are strongly suggestive of vulnerable plaque. This study aimed to investigate the relationship between intraplaque neovascularisation and plaque elasticity, and to compare the ultrasound findings with histopathological changes. METHODS: Patients enrolled in this study presented with symptomatic carotid stenosis (> 70%) and later underwent both pre-operative ultrasonography and endarterectomy. Contrast enhanced ultrasound (CEUS) and shear wave elastography (SWE) were used to measure the neovascularisation and elasticity of the plaque, respectively. After removal, plaques were histologically assessed to determine the microvessel density (MVD), matrix metalloproteinase (MMP)-9 expression, and type I/type III collagen ratio using immunohistochemistry staining and morphometry. A correlation analysis was used to establish the relationship among the aforementioned quantitative parameters. Inter- and intra-observer consistency evaluations were performed using the intraclass correlation coefficient and Bland-Altman plots. RESULTS: Ninety-four symptomatic patients with 98 plaques were included. The area under the curve (AUC) of the carotid plaque detected using CEUS correlated with its shear wave velocity (SWV) (r = -.714; p < .001), MVD (r = .842; p < .001), collagen type I/III ratio (r = -.833; p < .001), and MMP-9 (r = .738; p < .001). SWE was positively correlated with the type I/III collagen ratio (r = .805; p < .001). The overall interexaminer consistency of the SWE was acceptable (r = .638; p < .001). The interobserver correlation coefficient of the AUC, time to peak (TP), mean transit time (MTT), and SWV were .719, .756, .733, and .686, respectively. The intra-observer variability values of the AUC, TP, MTT, and SWV were .826, .845, .633, and .748, respectively. CONCLUSION: SWE and CEUS can comprehensively evaluate the vulnerability of the carotid plaque by assessing the elasticity of the plaque and neovascularisation within it. The negative correlation between the intraplaque neovascularisation and elasticity, further validated by histological findings, suggests that the more abundant the neovascularisation, the less elasticity.

Jamil, A. K., A. Alam, R. M. Youssef, J. Felius, J. S. van Zyl and R. L. Gottlieb (2021). “Pneumothorax and Pneumomediastinum in COVID-19 Suggest a Pneumocystic Pathology.” Mayo Clin Proc Innov Qual Outcomes 5(5): 827-834.

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OBJECTIVE: To determine whether the apparent excess incidence of pneumothorax and pneumomediastinum in patients with coronavirus disease 2019 (COVID-19) is explained adequately by iatrogenic causes vs reflecting sequelae of severe acute respiratory syndrome coronavirus 2 infection. PATIENTS AND METHODS: We retrospectively reviewed patients within our health care system from March 15, 2020, through May 31, 2020, who had a diagnosis of pneumothorax or pneumomediastinum during hospitalization for confirmed COVID-19 infection with attention to timing of pneumothorax and pneumomediastinum; presence, laterality, and placement, or attempts at central lines; and presence of mechanical ventilation before the event. RESULTS: We report clinical data and outcomes from 9 hospitalized patients with COVID-19 who developed pneumothorax and/or pneumomediastinum among more than 1200 hospitalized patients admitted within our hospital system early in the pandemic. Many events were inexplicable by iatrogenic needle injury, including 1 spontaneous case without central line access or mechanical ventilation. One occurred before central line placement, 2 in patients with only a peripherally inserted central line, and 1 contralateral to a classic central line. Three of these 9 patients died of complications of COVID-19 during their hospital stay. CONCLUSION: With COVID-19 affecting the peripheral lung pneumocytes, patients are vulnerable to develop pneumothorax or pneumomediastinum irrespective of their central line access site. We hypothesize that COVID-19 hyperinflammation, coupled with the viral tropism that includes avid involvement of peripheral lung pneumocytes, induces a predisposition to peripheral bronchoalveolar communication and consequent viral hyperinflammatory-triggered pneumothorax and pneumomediastinum.

Tenforde, M. W., M. M. Patel, A. A. Ginde, D. J. Douin, H. K. Talbot, J. D. Casey, N. M. Mohr, A. Zepeski, M. Gaglani, T. McNeal, S. Ghamande, N. I. Shapiro, K. W. Gibbs, D. C. Files, D. N. Hager, A. Shehu, M. E. Prekker, H. L. Erickson, M. C. Exline, M. N. Gong, A. Mohamed, D. J. Henning, I. D. Peltan, S. M. Brown, E. T. Martin, A. S. Monto, A. Khan, C. T. Hough, L. Busse, C. C. Ten Lohuis, A. Duggal, J. G. Wilson, A. J. Gordon, N. Qadir, S. Y. Chang, C. Mallow, H. B. Gershengorn, H. M. Babcock, J. H. Kwon, N. Halasa, J. D. Chappell, A. S. Lauring, C. G. Grijalva, T. W. Rice, I. D. Jones, W. B. Stubblefield, A. Baughman, K. N. Womack, C. J. Lindsell, K. W. Hart, Y. Zhu, S. M. Olson, M. Stephenson, S. J. Schrag, M. Kobayashi, J. R. Verani and W. H. Self (2021). “Effectiveness of SARS-CoV-2 mRNA Vaccines for Preventing Covid-19 Hospitalizations in the United States.” Clin Infect Dis Aug 6;ciab687. [Epub ahead of print].

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BACKGROUND: As SARS-CoV-2 vaccination coverage increases in the United States (US), there is a need to understand the real-world effectiveness against severe Covid-19 and among people at increased risk for poor outcomes. METHODS: In a multicenter case-control analysis of US adults hospitalized March 11-May 5, 2021, we evaluated vaccine effectiveness to prevent Covid-19 hospitalizations by comparing odds of prior vaccination with an mRNA vaccine (Pfizer-BioNTech or Moderna) between cases hospitalized with Covid-19 and hospital-based controls who tested negative for SARS-CoV-2. RESULTS: Among 1212 participants, including 593 cases and 619 controls, median age was 58 years, 22.8% were Black, 13.9% were Hispanic, and 21.0% had immunosuppression. SARS-CoV-2 lineage B.1.1.7 (Alpha) was the most common variant (67.9% of viruses with lineage determined). Full vaccination (receipt of two vaccine doses ≥14 days before illness onset) had been received by 8.2% of cases and 36.4% of controls. Overall vaccine effectiveness was 87.1% (95% CI: 80.7 to 91.3%). Vaccine effectiveness was similar for Pfizer-BioNTech and Moderna vaccines, and highest in adults aged 18-49 years (97.4%; 95% CI: 79.3 to 99.7%). Among 45 patients with vaccine-breakthrough Covid hospitalizations, 44 (97.8%) were ≥50 years old and 20 (44.4%) had immunosuppression. Vaccine effectiveness was lower among patients with immunosuppression (62.9%; 95% CI: 20.8 to 82.6%) than without immunosuppression (91.3%; 95% CI: 85.6 to 94.8%). CONCLUSION: During March-May 2021, SARS-CoV-2 mRNA vaccines were highly effective for preventing Covid-19 hospitalizations among US adults. SARS-CoV-2 vaccination was beneficial for patients with immunosuppression, but effectiveness was lower in the immunosuppressed population.

Tenforde, M. W., W. H. Self, E. A. Naioti, A. A. Ginde, D. J. Douin, S. M. Olson, H. K. Talbot, J. D. Casey, N. M. Mohr, A. Zepeski, M. Gaglani, T. McNeal, S. Ghamande, N. I. Shapiro, K. W. Gibbs, D. C. Files, D. N. Hager, A. Shehu, M. E. Prekker, H. L. Erickson, M. N. Gong, A. Mohamed, D. J. Henning, J. S. Steingrub, I. D. Peltan, S. M. Brown, E. T. Martin, A. S. Monto, A. Khan, C. L. Hough, L. W. Busse, C. C. Ten Lohuis, A. Duggal, J. G. Wilson, A. J. Gordon, N. Qadir, S. Y. Chang, C. Mallow, C. Rivas, H. M. Babcock, J. H. Kwon, M. C. Exline, N. Halasa, J. D. Chappell, A. S. Lauring, C. G. Grijalva, T. W. Rice, I. D. Jones, W. B. Stubblefield, A. Baughman, K. N. Womack, C. J. Lindsell, K. W. Hart, Y. Zhu, M. Stephenson, S. J. Schrag, M. Kobayashi, J. R. Verani and M. M. Patel (2021). “Sustained Effectiveness of Pfizer-BioNTech and Moderna Vaccines Against COVID-19 Associated Hospitalizations Among Adults – United States, March-July 2021.” MMWR Morb Mortal Wkly Rep 70(34): 1156-1162.

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Real-world evaluations have demonstrated high effectiveness of vaccines against COVID-19-associated hospitalizations (1-4) measured shortly after vaccination; longer follow-up is needed to assess durability of protection. In an evaluation at 21 hospitals in 18 states, the duration of mRNA vaccine (Pfizer-BioNTech or Moderna) effectiveness (VE) against COVID-19-associated hospitalizations was assessed among adults aged ≥18 years. Among 3,089 hospitalized adults (including 1,194 COVID-19 case-patients and 1,895 non-COVID-19 control-patients), the median age was 59 years, 48.7% were female, and 21.1% had an immunocompromising condition. Overall, 141 (11.8%) case-patients and 988 (52.1%) controls were fully vaccinated (defined as receipt of the second dose of Pfizer-BioNTech or Moderna mRNA COVID-19 vaccines ≥14 days before illness onset), with a median interval of 65 days (range = 14-166 days) after receipt of second dose. VE against COVID-19-associated hospitalization during the full surveillance period was 86% (95% confidence interval [CI] = 82%-88%) overall and 90% (95% CI = 87%-92%) among adults without immunocompromising conditions. VE against COVID-19- associated hospitalization was 86% (95% CI = 82%-90%) 2-12 weeks and 84% (95% CI = 77%-90%) 13-24 weeks from receipt of the second vaccine dose, with no significant change between these periods (p = 0.854). Whole genome sequencing of 454 case-patient specimens found that 242 (53.3%) belonged to the B.1.1.7 (Alpha) lineage and 74 (16.3%) to the B.1.617.2 (Delta) lineage. Effectiveness of mRNA vaccines against COVID-19-associated hospitalization was sustained over a 24-week period, including among groups at higher risk for severe COVID-19; ongoing monitoring is needed as new SARS-CoV-2 variants emerge. To reduce their risk for hospitalization, all eligible persons should be offered COVID-19 vaccination.