Author + information
- Thomas Richard Porter,
- Feng Xie,
- George P. Casale,
- Hernan Hernandez,
- Constance Mietus,
- Holly DeSpeigelaere and
- Iraklis Pipinos
Background: Defective capillary recruitment and skeletal microvascular blood flow (MBF) responses have been observed in peripheral arterial disease (PAD), but the frequency and significance of this in patients with exertional claudication is unknown.
Methods: In 20 patients with PAD involving at least one leg by Doppler exam, MBF and microvascular blood volume (MBV) were assessed in the gastrocnemius and soleus muscles of both legs at rest and following a 90 second ischemic period (thigh inflation to 90 mm Hg above systolic pressure) during a continuous infusion of Definity ultrasound contrast (3%; 4 ml/min) and low mechanical index (0.19 MI) triggered ultrasound imaging with intermittent high mechanical index impulses to examine both MBF and MBV using Q Lab software (Philips Healthcare). Defective capillary recruitment was defined as a < 2.0 fold increase in MBV(MBV ratio), and abnormal MBF as a <2.0 fold increase in replenishment rate*plateau intensity post ischemia (MBF ratio). Leg claudication was staged using a 0 (no PAD, no claudication), 1 (PAD, no claudication), and II (PAD with claudication). Ankle brachial indices (ABI) were measured at rest and following ischemia.
Results: A total of 39 legs could be analyzed. Mean age was 65+3 years. Three patients (15%) were diabetic, 10 (50%) had hypertension, and 12 (60%) were current smokers. Abnormal MBV and MBF ratios were seen with equal frequency in limbs with resting ABI values >0.9 (67%) compared to ABI<0.9 (60%). In limbs with ABI values <0.7 following ischemia, abnormal capillary recruitment was seen in 61%, but also occurred in 72% of limbs with ABI>0.7, while MBF ratios were abnormal in 29% of limbs with ABI<0.7 compared to 18% with ABI>0.7 post ischemia. MBF ratios were significantly lower in limbs of patients with Stage II PAD (3.1+1.6 Stage II PAD versus 5.4+6.4 Stage 0/1 PAD; p<0.05) but normal MBF responses following ischemia were still observed in 18 of the 25 limbs with resting ABI<0.9 and Stage II PAD.
Conclusions: These results indicate that abnormal skeletal MBF and capillary recruitment responses to ischemia are seen in patients with symptomatic PVD, but are independent of ABI values.
Poster Hall, Hall C
Saturday, March 18, 2017, 3:45 p.m.-4:30 p.m.
Session Title: New Technologies in Echocardiography
Abstract Category: 28. Non Invasive Imaging: Echo
Presentation Number: 1245-214
- 2017 American College of Cardiology Foundation