American Board of Pathology (ABPath) Practice Test 2025 - Free Pathology Exam Practice Questions and Study Guide

A tardus parvus waveform is indicative of stenosis, which refers to the narrowing of a blood vessel. This type of waveform is characterized by a delayed (tardus) and low-amplitude (parvus) appearance. It typically occurs in situations where there is significant obstruction in the vascular pathway, leading to reduced blood flow velocity and altered hemodynamics.

In normal situations, waveforms reflect a healthy flow of blood, usually demonstrating a rapid upstroke followed by a more pronounced dicrotic notch. However, stenosis causes turbulence and a decrease in the peak flow velocity. Hence, observing a tardus parvus waveform suggests that there is a significant narrowing in the artery upstream, which restricts blood flow and subsequently changes the flow pattern observed in doppler ultrasound studies.

The other options do not appropriately characterize the tardus parvus waveform. Increased blood flow would typically produce a high-velocity waveform with sharp peaks rather than a delayed and diminished pattern. Normal vascular responses would show typical biphasic or triphasic waveforms that represent good distal vascular function. Vasodilation would also not be characterized by a tardus parvus waveform, as it generally results in increased blood flow and a different waveform appearance due to the widening of blood vessels