An Alternative Method to Calculate Simplified Projected Aortic Valve Area at Normal Flow Rate / Um Método Alternativo para o Cálculo da Área Valvular Aórtica Projetada Simplificada em Uma Taxa de Fluxo Normal

Abstract Background: Simplified projected aortic valve area (EOAproj) is a valuable echocardiographic parameter in the evaluation of low flow low gradient aortic stenosis (LFLG AS). Its widespread use in clinical practice is hampered by the laborious process of flow rate (Q) calculation. Objetive: This study proposes a less burdensome, alternative method of Q calculation to be incorporated in the original formula of EOAproj and measures the agreement between the new proposed method of EOAproj calculation and the original one. Methods: Retrospective observational single-institution study that included all consecutive patients with classic LFLG AS that showed a Q variation with dobutamine infusion ≥ -15-% by both calculation methods. Results: Twenty-two consecutive patients with classical LFLG AS who underwent dobutamine stress echocardiography were included. Nine patients showed a Q variation with dobutamine infusion calculated by both classical and alternative methods ≥ -15-% and were selected for further statistical analysis. Using the Bland-Altman method to assess agreement we found a systematic bias of 0,037 cm2 (95% CI 0,004 - 0,066), meaning that on average the new method overestimates the EOAproj in 0,037 cm2 compared to the original method. The 95% limits of agreement are narrow (from -0,04 cm2 to 0,12 cm2), meaning that for 95% of individuals, EOAproj calculated by the new method would be between 0,04 cm2 less to 0,12 cm2 more than the EOAproj calculated by the original equation. Conclusion: The bias and 95% limits of agreement of the new method are narrow and not clinically relevant, supporting the potential interchangeability of the two methods of EOAproj calculation. As the new method requires less additional measurements, it would be easier to implement in clinical practice, promoting an increase in the use of EOAproj.

Resumo Fundamento: A área valvular aórtica projetada simplificada (AEOproj) é um parâmetro ecocardiográfico valioso na avaliação da estenose aórtica de baixo fluxo e baixo gradiente (EA BFBG). Sua utilização na prática clínica é limitada pelo trabalhoso processo de cálculo da taxa de fluxo (Q). Objetivos: Este estudo propõe um método alternativo, menos complexo, para o cálculo da Q para ser incorporado na fórmula original da AEOproj, e mede a concordância entre o novo método proposto para o cálculo da AEOproj em comparação ao método original. Métodos: Estudo retrospectivo, observacional, unicêntrico que incluiu todos os pacientes com AE BFBG clássica com variação da Q com infusão de dobutamina ≥ -15-% por ambos os métodos. Resultados: Foram incluídos 22 pacientes consecutivos com AE BFBG clássico, que se submeteram à ecocardiografia sob estresse com dobutamina. Nove pacientes apresentaram uma variação da Q com infusão de dobutamina calculada tanto pelo método clássico como pelo método alternativo ≥ -15-%, e foram selecionados para análise estatística. Utilizando método Bland-Altman para avaliar a concordância, encontramos um viés sistemático de 0,037 cm2 (IC 95% 0,004 - 0,066), o que significa que, em média, o novo método superestima a AEOproj em 0m037 cm2 em comparação ao método original. Os limites de concordância de 95% são estreitos (de -0,04 cm2 a 0,12 cm2), o que significa que para 95% dos indivídios, a AEOproj calculada pelo novo método estaria entre 0,04 cm2 menos a 0,12 cm2 mais que a AEOproj calculada pela equação original. Conclusão: O viés e os limites de 95% de concordância do novo método são estreitos e não são clinicamente relevantes, o que corrobora a intercambialidade dos dois métodos de cálculo da AEOproj. Uma vez que o novo método requer menos medidas, seria mais fácil de ser implementado na prática clínica, promovendo um aumento na utilização da AEOproj.

Development and in vitro permeation studies of proniosomal based transdermal delivery system of Atenolol

Proniosomes refer to a flexible vesicular carrier with the potential for drug administration through the transdermal route. A proniosome gel type transdermal delivery system of Atenolol was prepared and extensively studied both in vitro drug release and ex vivo permeation studies. The prepared formulations were evaluated for vesicle size, entrapment efficiency, in vitro drug loading, and drug release studies. The release of drug had shown considerable improvement in controlled manner from the prepared gel formulation. It was observed that Span 40 and 60 [A 8] based formulations shows vesicles of minimum size and higher entrapment efficiency compared to the other formulations. Proniosomal transdermal therapeutic system [A 8] was found to be the optimized formulation as it posses good drug release and shows permeation in a steady-state manner over a desired period of time. Also the drug diffusion across snake sheded skin, guinea pig abdomen skin, albino rat, porcine ear correlates better with in vitro drug release studies. The formulation was found to be stable when stored at room temperature and at refrigeration temperature [4 +/- 2degreeC] for 90 days.