Natural History of Cervical Artery Fibromuscular Dysplasia and Associated Neurovascular Events.

BACKGROUND AND PURPOSE: Fibromuscular dysplasia (FMD) is a non-atherosclerotic arteriopathy most often affecting the carotid and renal arteries. In the United States Registry for FMD, 41.7% of patients experienced an aneurysm and/or dissection by the time of entry into the Registry. We sought to determine the occurrence of neurovascular events after FMD diagnosis and any changes on cervical artery imaging that may be attributable to FMD. METHODS: Patients followed at the Mount Sinai Medical Center (US Registry for FMD enrollment center) with confirmed FMD and > 1 cervical artery imaging study (at least ± 6 months from the baseline carotid duplex ultrasound [CDU]) between the years 2003 and 2015 were included. Medical records and cervical artery imaging ([CDU], magnetic resonance angiogram [MRA], and computed tomography angiogram [CTA]) were reviewed. New arterial dissection, aneurysm, transient ischemic attack, stroke, or new FMD findings were recorded. RESULTS: Among 146 FMD patients with complete information, 52 (35.6%) had an aneurysm and 52 (35.6%) had a dissection. Mean clinical follow-up was 35.3 ± 25.3 months (range 5-153 months); patients underwent 4 ± 2.7 CDU (range 1-17); 86.3% had ≥1 neck MRA or CTA. After FMD diagnosis, 3 patients (2%) experienced a new carotid artery dissection; 1 patient experienced a stroke due to concomitant atherosclerosis. No new aneurysms occurred. In patients with cervical artery FMD, imaging findings remained stable throughout follow-up. No patient developed new cervical artery FMD findings on follow-up imaging. CONCLUSIONS: No new cervical artery FMD or aneurysm was observed on subsequent imaging. New carotid dissection was uncommon over a mean follow-up period of 35.3 ± 25.3 months and was the only non-atherosclerotic vascular event observed after FMD diagnosis.

The S curve: a novel morphological finding in the internal carotid artery in patients with fibromuscular dysplasia.

Fibromuscular dysplasia (FMD) is a non-atherosclerotic vascular disease commonly affecting the renal and internal carotid arteries (ICAs). A previously unrecognized finding is a redundancy of the mid-distal ICA in FMD patients causing an 'S'-shaped curve. Carotid artery duplex ultrasounds were reviewed in 116 FMD patients to determine S-curve prevalence. FMD patients with an S curve were matched to four control patients divided equally into two groups: (1) age and sex-matched and (2) age ≥70 and sex-matched. S curves were present in 37 (32%) FMD patients. Of these, nine (24%) had angiographic evidence of FMD in their ICA only, 13 (35%) had renal artery FMD only, and 15 (41%) had both ICA and renal FMD. Two patients in the age and sex-matched group had S curves (odds ratio 16.86, 95% CI 3.92-72.48; p<0.0001) while 12 (16.2%) patients in the age ≥70 and sex-matched group had S curves (odds ratio 2.42, 95% CI 1.16-5.03; p=0.016). In conclusion, the S curve is a novel morphological pattern of the mid-distal ICA. While the S curve may not be specific, its presence in individuals <70 years old should alert the clinician to the possibility that FMD is present.

Renal artery duplex ultrasound criteria for the detection of significant in-stent restenosis.

OBJECTIVES: To define velocity criteria by ultrasonography for the detection of hemodynamically significant (>60%) renal artery in-stent restenosis (ISR). BACKGROUND: The restenosis rate after renal artery stenting ranges between 10% and 20%. While duplex ultrasound criteria have been validated for native renal artery stenosis, there are no uniformly accepted validated criteria for stented renal arteries. METHODS: Vascular laboratory databases from two academic medical centers were retrospectively reviewed for patients who underwent renal artery stenting followed by duplex ultrasound evaluation and angiography (CT angiography or catheter angiography) as the gold standard. RESULTS: A cohort of 132 stented renal arteries that had angiographic comparisons was analyzed. Eighty-eight renal arteries demonstrated 0-59% stenosis while 44 renal arteries revealed 60-99% stenosis by angiography. Both the mean peak systolic velocity (PSV) and the renal artery-to-aortic ratio (RAR) were significantly higher in renal arteries with 60-99% restenosis compared with those with 0-59% restenosis (PSV: 382 cm/sec ± 128 vs. 129 cm/sec ± 62, P<0.001; RAR: 5.3 ± 2.4 vs. 2.1 ± 1.0, P <0.001). The optimal PSV and RAR cutoffs for detecting 60-99% ISR were calculated by receiver operator characteristics curve analysis. The velocity criteria that are associated with these results will be discussed. CONCLUSION: Duplex ultrasonography is an accurate technique to identify significant restenosis in stented renal arteries. The PSV and RAR cutoffs for detecting renal artery ISR are higher than those in native, unstented renal arteries. A normal duplex ultrasound after renal artery stenting virtually excludes significant restenosis.

Duplex ultrasound evaluation of hemodialysis access: a detailed protocol.

A detailed protocol for the performance and interpretation of duplex ultrasound evaluation of hemodialysis access is described.

Limitation of the resting ankle-brachial index in symptomatic patients with peripheral arterial disease.

Peripheral arterial disease (PAD) has been demonstrated to be prevalent in the primary care setting. However, it has also been shown to be unrecognized and under-treated. Owing to the association with cardiovascular disease it has been recommended to screen high-risk patients for PAD in the primary care setting using the ankle-brachial index (ABI). ABI has been demonstrated to be highly sensitive and specific in diagnosing PAD in patients with significant stenosis. However, the utility in patients with less severe stenosis and calcified vessels is in question. The aims of this study were to determine the diagnostic utility of measuring the ABI at rest in patients referred to the vascular laboratory for evaluation of suspected PAD, and to assess the added value of pulse volume recordings and post-exercise studies in patients with a normal ABI. A computerized vascular diagnostic laboratory database was queried for symptomatic outpatients referred for measurement of segmental blood pressure, the ABI or pulse volume recordings by physicians not specialized in the evaluation and management of patients with peripheral vascular disease. Of 707 patients undergoing outpatient physiologic arterial evaluations between February 1, 2003 and July 31, 2004, 396 met these inclusion criteria. Data recorded included resting ABI, ABI following treadmill exercise test and the presence of abnormal pulse volume recordings. The study population (n = 396) consisted of equal numbers of men and women (mean age 69 years, range 19-100 years). Among 396 studies, resting ABI values were normal in 183 (46.2%) and abnormal in 159 (40.2%). Of the 138 patients who underwent exercise testing, 84 had normal ABI readings at rest. In the 84 patients who had a normal ABI at rest and underwent exercise testing, the ABI fell below 0.9 after exercise in 26 (31%). Arterial non-compressibility was detected in 54 (13.6%) patients, whose average age was 67 years. Thirteen (24%) of those with non-compressible vessels had abnormal pulse volume recording (PVR) results, compared to five with normal resting ABI who had abnormal PVR findings (2.7%). In conclusion, this study demonstrated that nearly half of patients referred to the outpatient vascular laboratory because of suspected arterial disease had a normal resting ABI. While it is recommended that the ABI be measured at rest in patients at risk of PAD in primary care practice, these findings suggest that patients with symptoms of PAD should be more completely evaluated in a vascular laboratory. Furthermore, when the ABI is normal at rest in patients with symptoms of intermittent claudication, exercise testing is recommended to enhance the sensitivity for detection of PAD.