Peak Systolic Velocity Criteria Research Articles

Duplex ultrasound criteria for in-stent restenosis of mesenteric arteries

ObjectiveDuplex ultrasound (DUS) criteria are well defined for evaluating high-grade stenosis (≥70%) of the native superior mesenteric artery (SMA) and celiac artery (CA). It has been shown that native vessel criteria overestimate the degree of in-stent restenosis (ISR) and that velocity criteria for SMA and CA ISR are not well established. The objective of this study was to define DUS velocity criteria for high-grade ISR of the SMA and CA. MethodsA retrospective review of all patients who underwent SMA or CA stenting from a single institution was performed from 2004 to 2013. Patients were excluded if they did not have a DUS examination <4 months before angiography to assess stent patency or adequate angiographic visualization of the ISR. ResultsThere were 103 paired DUS scans and angiograms analyzed: 66 SMA studies and 37 CA studies. The average peak systolic velocity (PSV) for SMAs was 367 cm/s with <70% ISR and 536 cm/s with ≥70% ISR. The average PSV for CAs was 302 cm/s with <70% ISR and 434 cm/s with ≥70% ISR. For an ISR ≥70% in the SMA, a PSV ≥445 cm/s produced the highest sensitivity (83%) and specificity (83%), with a positive predictive value of 81% and a negative predictive value of 86%. For an ISR ≥70% in the CA, a PSV ≥289 cm/s produced the highest sensitivity (100%) and specificity (57%), with a positive predictive value of 79% and negative predictive value of 100%. ConclusionsIncreasing PSV correlates with an increasing degree of ISR for both the SMA and CA. Stented vessels have increased PSV, and therefore native PSV criteria are unreliable for the determination of ISR. The PSV criteria for ≥70% stenosis are higher for ISR than for native visceral vessel stenosis. The proposed new velocity criteria define ≥70% ISR as ≥445 cm/s in stented SMAs and ≥289 cm/s in stented CAs.

Transcranial Doppler screening in sickle cell disease: The implications of using peak systolic criteria.

To compare time average maximum mean velocity (TAMV) and peak systolic velocity (PSV) criteria of Trans Cranial Doppler (TCD) in their ability to predict abnormalities on magnetic resonance imaging (MRI)/magnetic resonance angiogram (MRA) in patients with sickle cell disease. A retrospective evaluation was performed of the outcomes in all patients with a Transcranial Doppler examination at our institution since the implementation of the hospital picture archiving and communication system (PACS) system in January 2003 through December 2012. All ultrasound imaging exams were performed by the same technologist with a 3 MHz transducer. Inclusion criteria was based upon the Transcranial Doppler procedure code in our PACS which had an indication of sickle cell disease in the history. The patient's age and gender along with the vessel with the highest time averaged mean velocity as well as the highest peak systolic velocity was recorded for analysis. A subset of the study cohort also had subsequent MR imaging and Angiograms performed within 6 mo of the TCD examination. MRI results were categorized as having a disease related abnormality (vessel narrowing, collateral formation/moya-moya, or abnormal fluid attenuation inversion recovery signal in parenchyma indicative of prior stroke) or normal. The MRI results formed the comparison standards for TCD exams in evaluating intracranial injury. Sensitivity and specificity for the two TCD criteria (TAMV and PSV) were calculated to determine which could be a better predictor for intracranial vasculopathy /clinically occult strokes. The study cohort for our institution was 110 patients with a total of 291 TCD examinations. These patients had a mean age of 7.6 years with a range from 2-18 years of age. Sixty-two of the 110 patients (56%) had two or more TCD exams. Thirty-seven patients (34%) had at least one MRI following a TCD examination. Of the 291 TCD examinations, 46 (16%) were conditional or abnormal by TAMV criteria. One hundred and sixteen (40%) were conditional or abnormal by PSV criteria. All studies that were abnormal by TAMV were also abnormal by PSV criteria. Seventy of the 116 (60%) studies which were conditional or abnormal by peak systolic criteria would not have been identified by time averaged mean maximum velocity criteria. The most frequent location of highest velocity measurement was noted to be in the middle cerebral artery regardless of whether it was measured by PSV or TAMV. From the 37 patients having one or more MRIs, 43 MRI exams were performed within 6 mo of a TCD examination. Twenty two (51%) MRIs had a disease related abnormality reported. When evaluating conditional or abnormal exams by PSV criteria against follow-up MRI/MRA, the sensitivity was 73% [16/(16 + 6)] and specificity was 81% [17/(4 + 17)]. When evaluating conditional or abnormal exams by TAMV criteria by follow-up MRI/MRA as the gold standard, the sensitivity was 41% [9/(9 + 13)] and the specificity was 100% [21/(21 + 0)]. In using conditional or abnormal criteria from PSV and TAMV to predict abnormalities on follow-up MRI/MR Angiogram, PSV was more sensitive (73% vs 41%) while TAMV was more specific (100% vs 81%). Based on the data obtained at our institution and using the assumption that the best screening test is the one with the highest sensitivity, the peak systolic velocity could be the measurement of choice for TCD screening.

Carotid duplex criteria for patients with contralateral occlusion

BackgroundContralateral occlusion (CLO) occurs in approximately 8% of patients undergoing intervention for carotid artery stenosis. Patients with CLO have increased stroke risk compared with patients without CLO, but standard carotid duplex ultrasonography (CDUS) criteria are not a reliable manner to screen or follow patients with CLO. Because appropriate duplex criteria for these patients are not well understood, this article defines CDUS parameters that accurately predict carotid artery stenosis at our institution. MethodsSixty-five patients with ipsilateral carotid stenosis and CLO were identified from our institutional database. Fifteen of sixty-five patients had arteriography, computed tomography angiography, or magnetic resonance angiography within 6 mo of CDUS. We determined accuracy of our laboratory's criteria for determining stenosis category compared with three-dimensional imaging. Receiver operating characteristic curves were used to determine optimal peak systolic velocity (PSV), end diastolic velocity (EDV), and systolic ratio (SR) cutoff values for diagnosing ≥50% stenosis in this pilot cohort. Finally, the revised criteria were prospectively applied to a validation cohort (n = 8) from the same institution. ResultsCategorization of stenosis by standard PSV, EDV, and SR criteria saw similar accuracy trends in both pilot (46.7, 53.3, and 66.7%) and validation (25, 25, and 62.5%) cohorts. Receiver operating characteristic curve analysis in the pilot cohort identified optimized PSV, EDV, and SR cutoffs (≥250, ≥90, and ≥2.3 cm/s, respectively) for diagnosing ≥50% stenosis. In the pilot cohort, new PSV criteria increased specificity (60%–100%) with minimal decreased sensitivity (90%–80%), whereas new EDV criteria increased specificity (40%–71.4%) and maintained 100% sensitivity. New SR criteria failed to improve sensitivity or specificity above 80%. Similar trends for the new CDUS velocity criteria were observed in the validation cohort. ConclusionsIncreasingly stringent ultrasound parameters can provide reliable criteria for determining ≥50% carotid stenosis in patients with CLO. Further prospective validation that includes more patients with high-grade ipsilateral stenosis will help identify the role of SR in segregating high-grade versus moderate stenosis in CLO patients.

Evaluation of flow velocity in unilateral middle cerebral artery stenosis by Transcranial Doppler.

To determine the optimal velocity values in diagnosing unilateral middle cerebral artery (MCA) stenosis by Transcranial Doppler (TCD), and improve the diagnostic accuracy using magnetic resonance angiography (MRA), a total of 302 unilateral MCA stenosis patients undergoing TCD also consented to a MRA of the intracranial arteries. The peak systolic velocity (PSV) and each MCA spectrum for each patient were recorded. Using the MRA to confirm, the degree of middle cerebral artery stenosis was categorized into four groups: normal (normal caliber and signal), mild (<50 %), moderate (50-69 %), severe (70-99 %, or no flow detected). The velocity difference among these four groups was significant (P < 0.001). The optimal PSV values for normal and stenosis were 160 cm/s. For mild and moderate were 200 cm/s, for moderate and severe were 280 cm/s. Using PSV as the diagnostic criteria, the Kappa number was >0.668. The optimal PSV differential value for mild and moderate was 70 cm/s, for moderate and severe at 120 cm/s. Optimal combined criteria for moderate stenosis were PSV >200 cm/s and PSV differential value >70 cm/s (specificity 87.2 %), for severe stenosis were PSV >280 cm/s and PSV differential value >120 cm/s (sensibility 81.6 %). Transcranial Doppler distinguishes normal and MCA stenosis with a reduced lumen diameter of less than 50 %. Using the PSV criteria, TCD has a high coincidence rate with MRA in the diagnosis of MCA stenosis. Combined PSV differential value and the abnormal spectrum may improve the accuracy of TCD in diagnosing moderate or severe stenosis.

Tandem High-grade Stenoses in the Innominate and Right Internal Carotid Arteries Diagnosed with Carotid Duplex Ultrasound

Peak systolic velocity criteria for assessing the severity of internal carotid artery (ICA) stenosis may be inadequate in the setting of a critical proximal lesion. A 54-year-old man with a history of panvascular atherosclerosis presented for re-evaluation of known carotid stenosis. Carotid duplex ultrasound was performed by using B-mode ultrasound (Philips) with color and pulsed Doppler. Velocities within the innominate artery were markedly increased (PSV 553 cm/sec; EDV 211 cm/sec), consistent with high-grade stenosis. Waveforms in the right subclavian and common carotid (CCA) arteries were poststenotic in appearance, and velocity in the distal right CCA was very low (PSV 39 cm/sec). There was an additional step-up in velocity in the proximal right ICA with extensive homogeneous plaque visualized (right ICA PSV 210 cm/sec; EDV 115 cm/sec). Although the ICA lesion did not meet peak systolic velocity or end diastolic velocity criteria for &gt;80% stenosis in our laboratory, the lesion was interpreted as an 80–99% lesion on the basis of the markedly increased ICA/CCA ratio (ICA/CCA ratio 5.38). The left subclavian artery had low, monophasic flow and was likely occluded near its origin with filling from a retrograde vertebral artery. The patient was referred for percutaneous intervention. Angiography confirmed a 99% stenosis of the innominate artery and a 90% stenosis of the right ICA in its proximal portion. The left subclavian artery was occluded. The left CCA arose from a bovine aortic arch. The innominate and right ICA lesions were treated successfully with balloon angioplasty and stenting. Duplex ultrasound is an outstanding diagnostic tool for the evaluation of extracranial carotid and innominate lesions. In the setting of tandem lesions, critical stenosis of the ICA may be missed with reliance on traditional PSV criteria alone. In such cases, interpretation of secondary criteria, particularly the ICA/CCA ratio, is crucial to establish an accurate diagnosis.

Colour-coded duplex assessment alone before carotid endarterectomy

This study assessed whether carotid colour-coded duplex imaging can provide sufficient information to investigate patients before carotid endarterectomy. One hundred patients with symptomatic carotid artery disease (amaurosis fugax 24, transient ischaemic attack 38 and established stroke 38) were assessed by both colour-coded duplex imaging and arch angiography. Stenoses were graded at angiography using the linear method from the European Carotid Surgery Trial and on duplex using peak systolic velocity criteria. Angiograms were also analysed for any arch or intracerebral pathology which would alter surgical management. In defining 70-99 per cent stenoses, duplex had a sensitivity of 98 per cent, specificity 96 per cent, positive predictive value of 96 per cent, negative predictive value 98 per cent and accuracy 97 per cent compared with angiography for both symptomatic and asymptomatic carotids (chi 2 = 1.22, 1 d.f., P = 0.25). With respect to the symptomatic carotid arteries angiography gave different information from duplex in six patients (6 per cent): definition of 70-99 per cent carotid stenosis was different (four), visualization was poor on duplex (one) and an intracerebral aneurysm was identified by angiography. One patient died following arch angiography as a result of mesenteric thrombosis. Carotid duplex imaging alone would appear to be sufficient to assess most patients before carotid endarterectomy as an accurate, safe and relatively cheap investigation compared with angiography. In cases where duplex assessment does not allow full visualization of the carotid bifurcation angiography is required.