Academic Appointments


  • Clinical Assistant Professor, Medicine

All Publications


  • Physiology of the Assisted Circulation in Cardiogenic Shock: A State-of-the-Art Perspective. The Canadian journal of cardiology Guihaire, J., Haddad, F., Hoppenfeld, M., Amsallem, M., Christle, J. W., Owyang, C., Shaikh, K., Hsu, J. L. 2020; 36 (2): 170–83

    Abstract

    Mechanical circulatory support (MCS) has made rapid progress over the last 3 decades. This was driven by the need to develop acute and chronic circulatory support as well as by the limited organ availability for heart transplantation. The growth of MCS was also driven by the use of extracorporeal membrane oxygenation (ECMO) after the worldwide H1N1 influenza outbreak of 2009. The majority of mechanical pumps (ECMO and left ventricular assist devices) are currently based on continuous flow pump design. It is interesting to note that in the current era, we have reverted from the mammalian pulsatile heart back to the continuous flow pumps seen in our simple multicellular ancestors. This review will highlight key physiological concepts of the assisted circulation from its effects on cardiac dynamic to principles of cardiopulmonary fitness. We will also examine the physiological principles of the ECMO-assisted circulation, anticoagulation, and the haemocompatibility challenges that arise when the blood is exposed to a foreign mechanical circuit. Finally, we conclude with a perspective on smart design for future development of devices used for MCS.

    View details for DOI 10.1016/j.cjca.2019.11.002

    View details for PubMedID 32036862

  • Machine learning algorithms to differentiate among pulmonary complications after hematopoietic cell transplant. Chest Sharifi, H. n., Lai, Y. K., Guo, H. n., Hoppenfeld, M. n., Guenther, Z. D., Johnston, L. n., Brondstetter, T. n., Chhatwani, L. n., Nicolls, M. R., Hsu, J. L. 2020

    Abstract

    Pulmonary complications, including infections, are highly prevalent in patients after hematopoietic cell transplant with chronic graft-versus-host disease. These comorbid diseases can make the diagnosis of early lung graft-versus-host disease (bronchiolitis obliterans syndrome) challenging. A quantitative method to differentiate among these pulmonary diseases can address diagnostic challenges and facilitate earlier and more targeted therapy.We conducted a single center study of 66 patients with computed tomography chest scans analyzed with a quantitative imaging tool known as parametric response mapping. Parametric response mapping results were correlated with pulmonary function tests and clinical characteristics. Five parametric response mapping metrics were applied to K-means clustering and support vector machine models to distinguish among post-transplant lung complications solely from quantitative output.Compared to parametric response mapping, spirometry showed a moderate correlation with radiographic air trapping, and total lung capacity and residual volume showed a strong correlation with radiographic lung volumes. K-means clustering analysis distinguished 4 unique clusters. Clusters 2 and 3 represented obstructive physiology (encompassing 81% of patients with bronchiolitis obliterans syndrome) in increasing severity (percent air trapping 15.6% and 43.0%, respectively). Cluster 1 was dominated by normal lung, and cluster 4 was characterized by patients with parenchymal opacities. A support vector machine algorithm differentiated bronchiolitis obliterans syndrome with specificity of 88%, sensitivity of 83%, accuracy of 86% and an area under the receiver operating characteristic curve of 0.85.Our machine learning models offer a quantitative approach for the identification of bronchiolitis obliterans syndrome versus other lung diseases, including late pulmonary complications after hematopoietic cell transplant.

    View details for DOI 10.1016/j.chest.2020.02.076

    View details for PubMedID 32343962

  • Strongyloides Hyperinfection After Immunosuppression in an Immigrant From El Salvador: A Case for Early Diagnosis and Treatment. Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases Hoppenfeld, M. S., Kennedy, V., Sheth, K., Chang, A., Nelson, J., Fairchild, R. M. 2018

    View details for PubMedID 30074914