Techniques for screening and monitoring patients for aortic aneurysms
An aortic aneurysm carries increasing risk of rupture with growing aneurysm diameter. This condition is typically asymptomatic, so screening and surveillance are essential. Ultrasound and other imaging methods are employed for such monitoring at high accuracy. However, these methods require an expert and are expensive. Aortic aneurysms are considerably under-detected at present and may become even more under-detected in the future as the disease prevalence increases with societal aging. This disclosure present devices that are convenient in use and cost for aortic aneurysm screening and surveillance.
1 . A method of screening for aortic aneurysms in a subject, comprising:
measuring, by a sensor, at least one arterial waveform in a subject;
measuring blood pressure of the subject;
extracting, by a signal processor, pulse wave velocity from the at least one arterial waveform;
dividing, by the signal processor, the pulse wave velocity by the blood pressure; and
detecting, by the signal processor, presence of an aortic aneurysm in the subject in response to a quotient of the pulse wave velocity divided by the blood pressure being less than a threshold.
2 . The method of claim 1 wherein measuring at least one arterial waveform comprises measuring a waveform indicative of blood volume using a photo-plethysmography (PPG) sensor.
3 . The method of claim 1 wherein measuring at least one arterial waveform comprises measuring a ballistocardiography waveform using an accelerometer or a weighing scale.
4 . The method of claim 1 further comprises measuring at least one arterial waveform using a sensor residing in a mobile phone.
5 . The method of claim 1 further comprises imaging the aortic aneurysm in the subject using an imaging device, where the imaging is in response to the step of detecting the aortic aneurysm using the extracted features.
6 . A method of screening for aortic aneurysms in a subject, comprising:
measuring, by a sensor, at least one arterial waveform in a carotid artery of the subject;
determining a first feature from the at least one arterial waveform, where the first feature is indicative of shape of the at least one arterial waveform during an upstroke of the at least one arterial waveform;
identifying an intersection of two lines fitted to an upstroke of the at least one arterial waveform,
determining a first value measured between a peak of the at least one arterial waveform and the intersection;
determining a second value measured between the peak of the at least one arterial waveform and the minimum of the at least one arterial waveform;
computing a ratio of the first value to the second value; and
detecting an aortic aneurysm in the subject in response to the ratio being greater than a threshold.
7 . A point-of-care device comprising:
a sensor configured to measure an arterial waveform in a subject;
a pressure sensor configured to measure blood pressure of the subject;
a signal processor in data communication with the sensor and the pressure sensor, wherein the signal processor operates to extract pulse wave velocity from the arterial waveform; divide the pulse wave velocity by the blood pressure; and detect presence of an aortic aneurysm in the subject in response to a quotient of the pulse wave velocity divided by the blood pressure being less than a threshold; and
an output in data communication with the signal processor and operable to provide an indicator for the aortic aneurysm.
8 . The point-of-care device of claim 7 wherein the sensor is further defined as a photo-plethysmography (PPG) sensor.