Severe Subclavian Artery Stenosis Research Articles

Abstract #1399545: Calcification of Left Atrial Appendage in Autosomal Recessive Hypophosphatemic Rickets Type 2 (ENPP1 Mutation)

Autosomal Recessive Hypophosphatemic Rickets type 2 (ARHR2) is a rare genetic condition secondary to a loss-of-function mutation in ENPP1 gene. ARHR2 is associated with renal phosphate wasting and suppressed 1,25-dihydroxyvitamin D due to increased FGF-23 levels and causing abnormal bone mineralization. Furthermore, as ENPP1 is implicated in the generation of PPi (inorganic pyrophosphate) which inhibits hydroxyapatite deposition, some ARHR2 patients present with life-treating generalized arterial calcification of infancy (GACI). We reported the case of a 32-year-old woman with a known diagnosis of ARHR2 since the age of seven. At that time, she presented a growth failure, bowed legs but no GACI history. She was treated from the age of 7 to 18 with phosphate supplements and calcitriol. She had ten surgeries for her leg deformities and had a subtotal parathyroidectomy at age 13 for primary hyperparathyroidism. She was referred to a tertiary centre for management of hypophosphatemia and diffuse bone pain. The alkaline phosphatase was at the upper limit of normal but imagings, including computed tomography scans and bone scintigraphy, did not show pseudofractures. Her chronic pain was associated with osteoarthritis and periarticular calcifications. She was treated for hypertension, and had a history of preeclampsia at 33 weeks of pregnancy. At the physical exam, a 30 mm Hg systolic blood pressure differential was noted between the right and left arms, suspect of severe subclavian artery stenosis. Additional investigations demonstrated a normal cardiac ultrasound (US), an Agatson score of 0 (coronary calcium scan) but extensive calcifications of the left atrial appendage, dense calcifications of the mitral valve and numerous calcifications in the ascending aortic wall. The spectrum of clinical manifestations associated with ENPP1-related conditions (GACI and ARHR2) is still unclear. In some patients who survive GACI, resolution of vascular calcifications has been reported. Furthermore, this case raises the possibility of undetected vascular calcifications in the infancy uncovered only after the diagnosis of ARHR2. Previous cases reported pulmonary stenosis, thickening of the aortic valve, and increased carotid intima-media thickness in patients with ARHR2 phenotype. Left atrial calcifications have been described in mechanical valve replacement, mitral stenosis, post-radiotherapy and in chronic kidney disease. Recommendations of cardiac US and kidney US have been proposed at the diagnosis of AHRH2. We further suggest vascular screening with cardiac scans to examine large vessels, and calcium score in these patients.

Frequency of subclavian artery stenosis in patients with mammarian artery coronary bypass and suspected coronary artery disease progression

We retrospectively analyzed patient records of all patients with a history of internal mammarian artery (IMA) coronary bypass undergoing coronary angiography at two cardiovascular centers between January 1st 1999 and December 31st 2019. A total of 11,929 coronary angiographies with or without percutaneous coronary intervention were carried out in 3921 patients. Our analysis revealed 82 (2%) patients with documented subclavian artery stenosis. Of these, 8 (10%) patients were classified as having mild, 18 (22%) moderate, and 56 (68%) severe subclavian artery stenosis. In 7 (9%) patients with subclavian artery stenosis, angiography revealed occlusion of the IMA graft. 26 (32%) patients with severe subclavian artery stenosis underwent endovascular or surgical revasculararization of the subclavian artery. In this retrospective multicenter study, subclavian artery stenosis was a relevant finding in patients with an internal mammarian artery coronary bypass graft undergoing coronary angiography. The development of dedicated algorithms for screening and ischemia evaluation in affected individuals may improve treatment of this potentially underdiagnosed and undertreated condition.

Pseudoshock: A Challenging Presentation of Bilateral Subclavian Artery Stenosis.

IntroductionSubclavian artery stenosis (SAS) is a manifestation of peripheral artery disease (PAD). Presentation varies, ranging from arm claudication and muscle fatigue to symptoms which reflect vertebrobasilar hypoperfusion, among which are syncope, ataxia and dysphagia. Although rare, severe bilateral SAS can exist and present as refractory hypotension. We describe a case of bilateral SAS masquerading as circulatory shock, or rather ‘pseudoshock’.Case DescriptionA 59-year-old female patient presented to the emergency department with complaints of dark stools. She was anaemic and hypotensive and therefore suspected to have an acute gastrointestinal bleed (GIB) with resultant haemorrhagic shock. Her hypotension was unresponsive to fluid resuscitation and blood transfusions. Bilateral upper extremity radial artery catheters confirmed low blood pressures. After her blood pressure failed to improve despite the addition of several vasopressors, a femoral artery catheter (FAC) was placed, which revealed significant hypertension discordant with the hypotension measured by the radial artery catheters. Review of CT angiography of the upper extremities revealed the presence of bilateral SAS which was deemed to be the aetiology of the falsely low blood pressure.DiscussionSAS should be suspected in patients with lower extremity PAD or a blood pressure (BP) differential of 15 mmHg or more between arms. When bilateral subclavian arteries are stenosed, this difference in BP may be concealed, making lower extremity BP measurements, as seen in non-invasive tests such as ankle brachial index (ABI) tests or through more invasive procedures such as FAC placement, critically important.ConclusionBilateral SAS may present as pseudo-hypotension. In cases of refractory shock of unclear aetiology, especially in patients with known PAD, a high index of suspicion is warranted for ‘pseudoshock’ secondary to severe vascular stenosis. Comparison of upper and lower extremity BP via invasive arterial catheters or non-invasive ABI tests can aid in the diagnosis of bilateral SAS.LEARNING POINTSBilateral subclavian artery stenosis (SAS) may present as pseudo-hypotension and shock of unclear aetiology.In patients with underlying peripheral arterial disease, pseudoshock should be considered in the differential diagnosis.Comparison of upper and lower extremity blood pressure via invasive arterial catheters or the non-invasive ankle brachial index (ABI) test has diagnostic value for bilateral SAS.Pseudoshock is managed via secondary prevention with antiplatelets and statins for asymptomatic patients, and revascularization for symptomatic patients.

頸部回旋により鎖骨下動脈盗血症候群を呈した高度鎖骨下動脈狭窄症の1例

頸部回旋により鎖骨下動脈盗血症候群を呈した高度鎖骨下動脈狭窄症の1例

Waveform Patterns and Peak Reversed Velocity in Vertebral Arteries Predict Severe Subclavian Artery Stenosis and Occlusion

This study investigated the value of analyzing spectral Doppler waveform patterns and measuring the peak reversed velocity (PRV) of the vertebral artery (VA) in predicting proximal severe subclavian artery (SA) stenosis and occlusion. Fifty-one patients with proximal SA stenosis were studied retrospectively. Based on the depth of the mid-systolic notch, the Doppler waveforms of the ipsilateral VA were divided into five subtypes (type I, n = 8; type II, n = 8; type III, n = 6; type IV, n = 13; and type V, n = 16). PRV was also measured. PRV receiver operating characteristic curves were constructed to obtain the best cutoff value for predicting severe SA stenosis or complete SA occlusion. The results indicated that both VA Doppler waveform and PRV were associated with the degree of SA stenosis (p < 0.05). PRV and the Doppler waveform in the VA had similar accuracy in predicting SA occlusion (84.3%, 43/51). PRV was more accurate than VA waveforms in predicting severe SA stenosis (98%, 50/51 vs. 94.1%, 48/51). However, no significant differences between the two methods in predicting severe SA stenosis were observed (p = 0.84). Thus, with severe obstruction of the SA, typical Doppler waveform patterns of the VA could be observed. PRV is a helpful criterion in predicting severe stenosis and occlusion of the SA.

Clinical research of angioplasty and stenting in the treatment for symptomatic severe subclavian artery stenosis

Background The major clinical presentation of severe subclavian artery stenosis is subclavian steal syndrome (SSS). At present, stent implantation has become a promising method for this disease. The aim of this article is to investigate the effectiveness and safeness of stent implantation in the treatment for symptomatic severe subclavian artery stenosis. Methods Clinical data of 20 patients with symptomatic severe subclavian artery stenosis treated via angioplasty and stenting from June 2012 to November 2012 were retrospectively analyzed. Results The procedure was technically successful in all of the 20 cases. Postoperative digital subtraction angiography (DSA) suggested the residual ratio of subclavian artery stenosis was < 20% . Straight-forward blood flow in vertebral artery, disappeared subclavian steal symptom and fluent blood flow in intracranial segment of ipsilateral vertebral artery were also seen. After procedure no stent⁃related complications were found. During the follow-up study from 10 days to 6 months, vessel ultrasound and computed tomography angiography (CTA) showed no in-stent restenosis, vessels with good form and fluent blood flow. Conclusion Percutaneous angioplasty and stenting is a minimally invasive, safe and effective method in the treatment for severe subclavian artery stenosis.

Evaluation of Severe Subclavian Artery Stenosis by Color Doppler Flow Imaging

This study evaluates the diagnostic value of the hemodynamic parameters of color Doppler flow imaging (CDFI) for severe (70 to 99%) subclavian artery stenosis (SAS) using digital subtraction angiography (DSA) as the reference standard. Two-hundred fifty-two patients with suspected SAS were recruited into the study and examined from June 2005 to December 2009. The degree of stenosis was classified as moderate (50 to 69%) or severe (70 to 99%) stenosis. By using CDFI, the residual diameter (Dr), peak systolic velocity (PSV1) and end diastolic velocity (EDV) at the stenotic vessel segments, as well as the original diameter (Do) and PSV2 of the relative normal segments distal to the stenosis (the segment distal to the poststenotic dilation) were recorded. The diameter stenosis rate (1-Dr/Do) and PSV ratio (PSV1/PSV2) were calculated. Using DSA as the reference standard, the diagnostic values and optimal cutoff values for each parameter for the evaluation of severe (70%-99%) were determined using receiving operating characteristic curve analysis. Among the 252 patients, 109 patients were diagnosed as having severe (70 to 99%) SAS and 143 patients had moderate (50 to 69%) SAS. The optimal cutoff values for PSV1, EDV and the PSV1/PSV2 ratio for evaluating severe (70 to 99%) SAS were PSV1 ≥343 cm/s, EDV ≥60 cm/s and PSV1/PSV2 ≥4.0, respectively. The accuracy for diagnosing SAS with PSV1 (86.1%) was higher than that of EDV (85.7%), PSV1/PSV2 (84.9%) and 1-Dr/Do (80.2%). In addition, when PSV1 was used in combination with EDV and 1-Dr/Do, the accuracy for diagnosing SAS increased from 86.1% to 87.3%. When PSV1 was used in combination with EDV and PSV1/PSV2, the accuracy for diagnosing SAS reached 95.8%. In conclusion, the CDFI hemodynamic parameters of PSV1, EDV and PSV1/PSV2 show good consistency with DSA for diagnosing severe (70 to 99%) SAS, and a combination of these three parameters can ensure even greater accuracy for diagnosing SAS. (E-mail: dryanghua@sohu.com)