Evaluation of the diagnostic accuracy of exome sequencing and its impact on diagnostic thinking for patients with rare disease in a publicly funded health care system: A prospective cohort study.

PURPOSE: To evaluate the diagnostic utility of publicly funded clinical exome sequencing (ES) for patients with suspected rare genetic diseases. METHODS: We prospectively enrolled 297 probands who met eligibility criteria and received ES across 5 sites in Ontario, Canada, and extracted data from medical records and clinician surveys. Using the Fryback and Thornbury Efficacy Framework, we assessed diagnostic accuracy by examining laboratory interpretation of results and assessed diagnostic thinking by examining the clinical interpretation of results and whether clinical-molecular diagnoses would have been achieved via alternative hypothetical molecular tests. RESULTS: Laboratories reported 105 molecular diagnoses and 165 uncertain results in known and novel genes. Of these, clinicians interpreted 102 of 105 (97%) molecular diagnoses and 6 of 165 (4%) uncertain results as clinical-molecular diagnoses. The 108 clinical-molecular diagnoses were in 104 families (35% diagnostic yield). Each eligibility criteria resulted in diagnostic yields of 30% to 40%, and higher yields were achieved when >2 eligibility criteria were met (up to 45%). Hypothetical tests would have identified 61% of clinical-molecular diagnoses. CONCLUSION: We demonstrate robustness in eligibility criteria and high clinical validity of laboratory results from ES testing. The importance of ES was highlighted by the potential 40% of patients that would have gone undiagnosed without this test.

Novel theranostic approaches to neovascularized atherosclerotic plaques.

As the global burden of atherosclerotic cardiovascular disease continues to rise, there is an increased demand for improved imaging techniques for earlier detection of atherosclerotic plaques and new therapeutic targets. Plaque lesions, vulnerable to rupture and thrombosis, are thought to be responsible for the majority of cardiovascular events, and are characterized by a large lipid core, a thin fibrous cap, and neovascularization. In addition to supplying the plaque core with increased inflammatory factors, these pathological neovessels are tortuous and leaky, further increasing the risk of intraplaque hemorrhage. Clinically, plaque neovascularization has been shown to be a significant and independent predictor of adverse cardiovascular outcomes. Microvessels can be detected through contrast-enhanced ultrasound (CEUS) imaging, however, clinical assessment in vivo is generally limited to qualitative measures of plaque neovascularization. There is no validated standard for quantitative assessment of the microvessel networks found in plaques. Advances in our understanding of the pathological mechanisms underlying plaque neovascularization and its significant role in the morbidity and mortality associated with atherosclerosis have made it an attractive area of research in translational medicine. Current areas of research include the development of novel therapeutic and diagnostic agents to target plaque neovascularization stabilization. With recent progress in nanotechnology, nanoparticles have been investigated for their ability to specifically target neovascularization. Contrast microbubbles have been similarly engineered to carry loads of therapeutic agents and can be visualized using CEUS. This review summarizes the pathogenesis, diagnosis, clinical significance of neovascularization, and importantly the emerging areas of theranostic tool development.

Vascularized Carotid Atherosclerotic Plaque Models for the Validation of Novel Methods of Quantifying Intraplaque Neovascularization.

BACKGROUND: Intraplaque neovascularization (IPN) in advanced lesions of the carotid artery has been linked to plaque progression and risk of rupture. Quantitative measurement of IPN may provide a more powerful tool for the detection of such "vulnerable" plaque than the current visual scoring method. The aim of this study was to develop a phantom platform of a neovascularized atherosclerotic plaque within a carotid artery to assess new methods of quantifying IPN. METHODS: Ninety-two synthetic plaque models with various IPN architectures representing different ranges of IPN scoring were created and assessed using contrast-enhanced ultrasound. Intraplaque neovascularization volume was calculated from contrast infiltration in B mode. The plaque models were used to develop a testing platform for IPN quantification. A neovascularized enhancement ratio (NER) was calculated using commercially available software. The plaque model NERs were then compared to human plaque NERs (n = 42) to assess score relationship. Parametric mapping of dynamic intensity over time was used to differentiate IPN from calcified plaque regions. RESULTS: A positive correlation between NER and IPN volume (rho = 0.45; P < .0001) was found in the plaque models. Enhancement of certain plaque model types showed that they resembled human plaques, with visual grade scores of 0 (NER mean difference = 1.05 ± SE 2.45; P = .67), 1 (NER mean difference = 0.22 ± SE 3.26; P = .95), and 2 (NER mean difference = -0.84 ± SE 3.33; P = .80). An optimal cutoff for NER (0.355) identified grade 2 human plaques with a sensitivity of 95% and specificity of 91%. CONCLUSIONS: We developed a carotid artery model of neovascularized plaque and established a quantitative method for IPN using commercially available technology. We also developed an analysis method to quantify IPN in calcified plaques. This novel tool has the potential to improve clinical identification of vulnerable plaques, providing objective measures of IPN for cardiovascular risk assessment.