The CRU Cardiovascular Core Laboratory is located on the 3rd floor of the B- Building at Johns Hopkins Bayview Medical Center. A full time Echocardiography Technician registered by the American Registry of Diagnostic Sonographers staffs the facility. Investigators are asked to contact the CRU Adminstrator with questions regarding testing or resources allocation.

• Echocardiogram - Echocardiographic imaging is performed using either the Philips Sonos 5500 or Toshiba Aplio ultrasound system. All cardiac studies are performed and stored digitally, then analyzed using the Philips Excelera System. Image acquisition and analysis protocols can be customized to meet the needs of the investigator.

• Carotid IMT- Carotid imaging is performed using either the Philips Sonos 5500 or Toshiba Aplio ultrasound system. Using commercially available state of the art equipment that includes automated border detection, the core lab can accurately measure carotid intima medial thickness and carotid luminal diameter to calculate distensibility.
• Brachial Reactivity Studies- Brachial ultrasound studies are performed using a Philips Sonos 5500 or Toshiba Aplio system. A high frequency (15Mhz) ultrasound transducer is held in place by a mounted stationary device to insure reproducibility of brachial reactivity measures. The Cardiovascular Core Lab performs endothelial function tests using both cuff inflation and nitroglycerin to induce brachial flow mediated dilatation (FMD). Analysis of both brachial diameter and flow velocity is performed using state of the art commercially available equipment with automated edge detection.
• Aortic Pulse Wave Velocity- Aortic Pulse Wave Velocity is a measure of arterial stiffness. Simultaneous recordings of the arterial flow waves are made from the right common carotid and right femoral arteries using nondirectional transcutaneous Doppler flow probes. An ECG rhythm strip is also recorded. Waveform analysis and calculation of PWV are made using software developed by the Laboratory of Cardiovascular Science, Gerontology Research Center, NIA.
• Carotid Pressure Pulse Augmentation Index (AGI)- AGI is a measure of central SBP augmentation arising mainly from pressure-wave reflection in the aorta. The use of applanation tonometry to calculate AGI is widely used in studies of vascular stiffness. Arterial pressure waveforms are obtained from the right carotid artery using applanation tonometry, using a pencil-sized probe (SPR-428 Millar Instruments, Inc, Houston, TX) over the maximal pulsation of the artery. A computer algorithm, using the derivatives of the pressure wave, plots the timing of the foot, shoulder, and peak of the transcutaneously obtained arterial pressure contour. The AGI for each averaged waveform is the height from the shoulder to the peak of the pressure waveform divided by the height from the foot to peak, expressed as a percent.

Contact Pamela Ouyang, MBBS Program Director ICTR Clinical Research Unit 4940 Eastern Avenue Baltimore, MD 21224 Phone: 410-550-1850 Fax: 410-550-1227 pouyang1@jhmi.edu Sandra Lima,RDCS Cardiovascular Sonographer Phone: 410-550-6720 Fax: 410-550-1227 slima1@jhmi.edu