Atherosclerotic Occlusive Disease Research Articles

Assessment of Hemodynamic Compromise Using Computed Tomography Perfusion in Combination with 123I-IMP Single-Photon Emission Computed Tomography without Acetazolamide Challenge Test

The acetazolamide challenge test in conjunction with 123I-IMP single-photon emission computed tomography (SPECT) is a known method of assessing cerebrovascular reserve capacity. In this study, we investigated whether CT perfusion in combination with resting state 123I-IMP SPECT could be used instead of the acetazolamide challenge test to evaluate hemodynamic compromise in patients with atherosclerotic occlusive disease. Twenty consecutive patients with unilateral internal carotid artery or middle cerebral artery steno-occlusive disease were enrolled. 123I-IMP SPECT was performed with and without the acetazolamide challenge test, and with CT perfusion. Cerebral blood flow (CBF), cerebral blood volume, and mean transit time (MTT) obtained by CT perfusion were compared with CBF and cerebrovascular reactivity (CVR) obtained by 123I-IMP SPECT. The asymmetry ratio of MTT as measured by CT perfusion showed a strong correlation with the CVR to acetazolamide as measured by 123I-IMP SPECT (ρ = -.780, P <.001). Based on the CBF obtained through 123I-IMP SPECT and the MTT obtained through CT perfusion, hemodynamic compromise was detected with high sensitivity (1.000) and specificity (.929), and a cutoff value of 30% was found to be suitable for the asymmetry ratio of MTT. MTT prolongation was significantly improved after revascularization surgery in hemodynamic compromise (P = .028). MTT as measured by CT perfusion in combination with CBF as measured by resting state 123I-IMP SPECT may be useful for evaluating hemodynamic compromise as an alternative to the acetazolamide challenge test.

Superficial temporal artery to middle cerebral artery bypass with interposed saphenous vein graft in patients with atherosclerotic internal carotid artery occlusive disease and impaired cerebral hemodynamics.

The aim of this study was to evaluate the efficacy of interposed saphenous vein graft (SVG) usage during extracranial-intracranial (EC-IC) bypass surgery in patients with cerebral ischemia and appropriate donor artery absence. Since October 2010 till January 2014, 62 EC-IC bypass surgeries were applied in 60 patients. In nineteen patients SVG was used to create low-flow bypasses between superficial temporal artery trunk and cortical segment of middle cerebral artery. SVG was used due to inappropriate diameter of scalp artery in 12 cases, inadequate flow in intended donor artery in 5 patients and in 2 cases for other reasons. Indications for revascularization were based on clinical symptoms of cerebral hemodynamics impairment, confirmed with transcranial duplex ultrasonography (DUS) and brain perfusion computed tomography (CT). Early bypass patency was confirmed with DUS up to 9 postoperative day in 16 patients. In 3 (15.8%) patients blood flow was not visualized. Bypass patency in these patients was confirmed with repeated DUS up to 42 months period. At mean clinical follow-up of 22.3 months 14 patients (73.7%) reported an improvement of their condition, 4 patients (21%) didn't observe any changes in well-being and 1 patient (5.3%) got worse. Late bypass patency assessment was available and confirmed in 16 patients at mean follow-up of 15.6 months postoperation. Repeated brain perfusion CT was performed in 10 patients at mean follow-up of 5.2 months. Average growth of regional cerebral blood flow was 24.1%. The use of interposed SVG bypass for EC-IC revascularization is an effective method, that could be applied in patients with cerebral ischemia caused by internal carotid artery occlusive disease and absence of appropriate donor artery.

Tibioperoneal Occlusive Disease: A Review of below the Knee Endovascular Therapy in Patients with Critical Limb Ischemia

Tibioperoneal occlusive disease is one of the most difficult disease processesto successfully treat. Previous studies have attempted to address the outcomes of tibial interventions in this patient population; however, the majority of these study cohorts are composed of patients who have undergone concomitant aortoiliac or femoral procedures. Our objective was to present the outcomes of patients treated with endovascular intervention for isolated below-the-knee atherosclerotic disease causing critical limb ischemia (CLI). We performed a retrospective review of all patients who underwent isolated endovascular treatment of the below-knee popliteal, tibial, and/or peroneal arteries for CLI (Rutherford class 4-6). Primary outcomes include wound healing, reintervention rates, and amputation-free survival out to 5 years, as well as 1-year primary patency rates. 116 patients were identified as having undergone a tibial endovascular intervention. Ninety-two had concomitant aortoiliac or femoropopliteal interventions; after excluding those patients, we identified 24 limbs that were treated for isolated below-knee popliteal, tibial, and/or peroneal occlusive disease using an endovascular modality. 62.5% of limbs had successful wound healing, whereas 37.5% eventually required a major amputation. Mean time to amputation was 514.6days (standard error: 57.3). Of those patients with successful limb salvage (n=15), 66.7% required only the index procedure to heal; the remaining 33.3% required a repeat endovascular intervention, an arterial bypass, or a combination to successfully heal. The mean time to reintervention was 780.1days (standard error: 179.5). The 1-year primary patency rate was 52.6% (n=19). Patients with CLI secondary to isolated below-the-knee atherosclerotic occlusive disease are a difficult population to successfully treat; despite this, these patients benefit from an initial attempt at endovascular limb salvage. In our experience, this approach resulted in a respectable limb salvage rate of 62.5% and did not compromise open surgical solutions in the event of nonhealing.

Abstract 312: Arterial CEPT1 Expression Correlates With Diabetes and Atherosclerotic Occlusive Disease

Choline/ethanolamine phosphotransferase-1 (CEPT1) is a ubiquitously expressed enzyme that catalyzes the final step in synthesis of the majority of mammalian phospholipids, that are known to also impact atheroprogression. We previously found that in the setting of diabetes CEPT1 expression and downstream phospholipid biosynthesis are critically altered in hepatocytes. We therefore hypothesized that in diabetes CEPT1 expression is also altered in arterial tissue, and correlates with disease severity. To test this hypothesis we evaluated CEPT1 protein expression in murine and human arterial tissue in the presence or absence of diabetes, and/or advanced occlusive disease. CEPT1 expression in the aorta of Db/Db mice was 43% increased relative to Wt controls (n=7 per mouse group;p=0.03). On the other hand, CEPT1 expression was not significantly altered in Db/Db myocardial or skeletal muscle (p=0.2 and p=0.09, respectively). To determine whether our findings translate to similar CEPT1 expression patterns in human arterial tissue, we harvested carotid artery intima from 11 diabetic and 7 non-diabetic patients undergoing carotid endarterectomy (CEA). We also harvested peripheral arterial segments with minimal and maximal atherosclerotic occlusive disease from 8 diabetic and 4 non-diabetic patients undergoing lower extremity amputation. Relative to non-diabetic patients, patients who were diabetic had increased CEPT1 expression in CEA tissue (53% increase;p=0.05), and peripheral arterial segments (36% increase;p=0.04). Interestingly, relative to peripheral arteries with minimal atherosclerotic occlusive disease, segments with maximal disease had a two-fold increase in CEPT1 expression (p&lt;0.01). Analysis of maximally diseased peripheral arteries demonstrated significantly higher CEPT1 expression among diabetic patients (34% increase;p=0.03). There was no difference in CEPT1 expression in minimally diseased arteries of diabetic and non-diabetic patients (p=0.1). These findings highlight that increased CEPT1 expression correlates with diabetes and extent of arterial occlusive disease. Furthermore, they argue that CEPT1 is a unique arterial tissue biomarker for occlusive disease severity.

Topologic distributions of vasa vasorum and lymphatic vasa vasorum in the aortic adventitia – Implications for the prevalence of aortic diseases

Background and aimsVasa vasorum (VV) and lymphatic vasa vasorum (LVV) form their own networks in the adventitia. VV supply the aorta with nutrition and oxygen; however, the distribution and role of LVV remains to be determined. The purpose of this study was to investigate differences in the distribution of VV and LVV along the aorta. MethodsAortic samples were obtained from 22 autopsy cases without medical history of aortic diseases. Aortic segments were classified as arch (Ar), descending thoracic (De), suprarenal abdominal (S-Ab), and infrarenal abdominal (I-Ab). Adventitial VV and LVV were identified immunohistochemically. ResultsVV were most dense in the arch aorta, becoming less dense along the aorta in more distal segments, with the lowest density occurring in the infrarenal abdominal aorta. There was a significant correlation between the numbers of VV and medial thickness in the total aortic segments (r = 0.518, p < 0.01). In contrast, there was no significant correlation between the number of LVV and medial thickness in any aortic segments. However, there was a significant correlation between the number of LVV and intimal thickness in I-Ab (r = 0.425, p < 0.05). ConclusionsThe distributions of adventitial VV and LVV were characteristic along the aortic segments. Differences in the distributions may imply the prevalence of aortic diseases such as dissection, abdominal aortic aneurysm, and atherosclerotic occlusive disease in each aortic segment.

Interpretation and consideration of the Society for Vascular Surgery practice guidelines for atherosclerotic occlusive disease of the lower extremities management of asymptomatic disease and claudication

Atherosclerotic occlusive disease of the lower extremities (ASO-LE) has the third highest rate among systematic atherosclerosis obliterans, ranking after coronary heart disease and stoke, and the disease burden of ASO-LE has been continuously increasing. Invasive revascularizations, which is presented by endovascular therapy technique, has undergone a dramatic development in the past couples of decades. However, controversy concerned about the surgical management and operative indications has heated up in the meanwhile. Thus Society for Vascular Surgery (SVS) published the practice guidelines for ASO-LE with asymptomatic disease and claudication in March, 2015. At the first time the guideline definitely opposed the aggressive invasive revascularization for ASO-LE patients with asymptomatic disease or claudication under satisfied tolerance. Instead, it posed the extreme emphasis on the pharmacotherapy with risk reduction of atherosclerosis at the core and the exercise therapy with supervised or home-based exercise program at the core for ASO-LE patients with asymptomatic disease and claudication.

Matrix Gla-Protein (MGP) Not Only Inhibits Calcification in Large Arteries But Also May Be Renoprotective: Connecting the Dots

Matrix Gla-Protein (MGP) Not Only Inhibits Calcification in Large Arteries But Also May Be Renoprotective: Connecting the Dots

Neurocognitive Improvement in Patients Undergoing Carotid Endarterectomy for Atherosclerotic Occlusive Carotid Artery Disease.

Objectives: To assess the improvement in neurocognitive functions after carotid endarterectomy (CEA) under local anesthesia (LA) in patients with carotid bifurcation occlusive disease. Place and duration of study: Department of Vascular Surgery, Combined Military Hospital Lahore from January 2013 to January 2015. Patients and Methods: A total of 79 patients with carotid artery occlusive disease, having no history of major stroke, depression, or dementia underwent CEA under LA. Cognitive functions were assessed 3 days before surgery and then 4 weeks and 12 weeks after the surgery using the Addenbrookes cognitive examination (ACE) score and General Practitioner Assessment of Cognition (GPCOG) Score. Results: In ACE score, Attention, Memory, Fluency, Language, and Visuospatial orientation improved by 33.3%, 30.7%, 21.4%, 38.4%, and 31.2%, respectively, by the end of 12 weeks. An overall improvement in neurocognition was 32% (P = 0.03). In GPCOG score, Orientation, Recall, and Memory improved by 33%, 20%, and 100%, respectively, with an overall improvement of 33.3% at the end of 12 weeks (P = 0.02). Conclusion: Both scoring systems show an overall improvement in neurocognition as well as improvements in all the subcategories in each system. Hence, we conclude statistically significant improvement in neurocognitive functions after CEA.

Comparative results of surgical treatment of bilateral atherosclerotic occlusive stenotic carotid artery disease

Comparative results of surgical treatment of bilateral atherosclerotic occlusive stenotic carotid artery disease

Epidemiology.

Intracranial atherosclerotic occlusive disease is an important and possibly the most common cause of stroke worldwide. Asian, Black and certain Hispanic populations have a high risk of harboring intracranial occlusive disease. In this chapter we review the epidemiology of intracranial occlusive disease by primarily focusing on studies from China, Japan, Korea, and other Asian countries. In addition, we compare and contrast the information from Asian countries with that from North America and related regions. Finally, we explore hypotheses concerning the origin of race-ethnic differences in the distribution of extracranial and intracranial atherosclerotic disease.

Total occlusion of the abdominal aorta in a patient with renal failure and refractory hypertension: a case report

Total occlusion of the abdominal aorta is unusual, and potentially catastrophic. It occurs in patients with advanced atherosclerotic occlusive disease, and can cause severe ischemic manifestations, depending on the site of obstruction. Prompt and appropriate diagnostic and therapeutic approaches are important whenever this condition is suspected, in order to avoid a fatal outcome. The development of a complex network of collaterals may prevent the manifestation of acute ischemic phenomena, and cause a delay in diagnosis and treatment. Here we report the clinical case of a 59-year-old man who was referred to our Department for evaluation of renal failure and refractory hypertension. Ultrasonography and 99mTc-DTPA scintigraphy showed a shrunken, non-functioning left kidney, while CT angiography and aortography showed the complete occlusion of the aorta from below the right renal artery down to the bifurcation of both common iliac arteries, with a critical stenosis of the origin of the right renal artery, an occlusion of the left renal artery as well as of the origin of the inferior mesenteric artery. The patient was referred to the surgery department for aorto-bifemoral bypass surgery and re-implantation of the right renal artery.

A woman with recurrent chest pain and ST-segment elevation

A 32-year-old female presents with recurrent episodes of unprovoked chest pain associated with inferior ST-segment elevation and reciprocal ST-segment depression. Coronary angiography during one of these episodes revealed coronary artery spasm that spontaneously resolved followed by resolution of these electrocardiographic changes. There was no atherosclerotic occlusive disease. Her cardiac markers were normal and echocardiogram showed no regional wall motion abnormalities. Electrocariogram and angiography findings are shown in Fig. 1.

Impaired Coronary and Renal Vascular Function in Spontaneously Type 2 Diabetic Leptin-Deficient Mice.

BackgroundType 2 diabetes is associated with macro- and microvascular complications in man. Microvascular dysfunction affects both cardiac and renal function and is now recognized as a main driver of cardiovascular mortality and morbidity. However, progression of microvascular dysfunction in experimental models is often obscured by macrovascular pathology and consequently demanding to study. The obese type 2 diabetic leptin-deficient (ob/ob) mouse lacks macrovascular complications, i.e. occlusive atherosclerotic disease, and may therefore be a potential model for microvascular dysfunction. The present study aimed to test the hypothesis that these mice with an insulin resistant phenotype might display microvascular dysfunction in both coronary and renal vascular beds.Methods and ResultsIn this study we used non-invasive Doppler ultrasound imaging to characterize microvascular dysfunction during the progression of diabetes in ob/ob mice. Impaired coronary flow velocity reserve was observed in the ob/ob mice at 16 and 21 weeks of age compared to lean controls. In addition, renal resistivity index as well as pulsatility index was higher in the ob/ob mice at 21 weeks compared to lean controls. Moreover, plasma L-arginine was lower in ob/ob mice, while asymmetric dimethylarginine was unaltered. Furthermore, a decrease in renal vascular density was observed in the ob/ob mice.ConclusionIn parallel to previously described metabolic disturbances, the leptin-deficient ob/ob mice also display cardiac and renal microvascular dysfunction. This model may therefore be suitable for translational, mechanistic and interventional studies to improve the understanding of microvascular complications in type 2 diabetes.

IF15. A Case-Control Study of Lipoprotein(a) Levels in Atherosclerotic Peripheral Arterial Occlusive Disease in Indian Population: Original Study

IF15. A Case-Control Study of Lipoprotein(a) Levels in Atherosclerotic Peripheral Arterial Occlusive Disease in Indian Population: Original Study

Duplex Ultrasound Assessment of Native Stenoses in the Superficial Femoral and Popliteal Arteries

Purpose: To evaluate duplex ultrasonography (DUS) in the assessment of femoropopliteal stenoses comparing a single native stenosis (SNS) to multisegmental native stenoses (MNS). Methods: Among the 1284 patients treated for atherosclerotic occlusive disease involving the femoropopliteal segment between November 2002 and November 2012, 139 patients (97 men; mean age 68±8 years) with 142 SNS or 143 MNS in 79 and 60 patients, respectively, were eligible for this retrospective analysis. The peak systolic velocity ratios with proximal (PSVRprox) and distal (PSVRdist) reference for the 285 lesions were compared with their respective angiographic stenosis grade as measured by 2 independent readers using quantitative vascular analysis to ensure objectivity. Receiver operating characteristic curve analysis was used to evaluate sensitivity, specificity, and the optimal thresholds of PSV and PSVR for detection of stenoses by grade (>50%, >70%, or >80% diameter stenosis). The area under the curve (AUC) values of dependent and independent receiver operating characteristic curves were compared. Results: For SNS, correlation of PSVRprox to diameter stenosis (R=0.88) was higher (p<0.001) than the correlation for MNS (R=0.78). In the SNS group, the AUC for detecting a >50% (0.99±0.01), >70% (0.98±0.01), and >80% (0.96±0.01) stenosis with PSVRprox was significantly higher than in the MNS group [AUC50% 0.93±0.02 (p=0.01), AUC70% 0.92±0.02 (p=0.02), and AUC80% 0.87±0.03 (p=0.003)]. The optimal thresholds for detecting >50%, >70%, and >80% stenoses for SNS using PSVRprox were 2.6, 3.3, and 3.9, respectively. For MNS, the optimal thresholds of PSVRprox were 2.6, 3.4, and 3.9, respectively, with respective sensitivities of 87%, 81%, and 75%; respective specificities of 93%, 90%, and 82%; negative predictive values of 45%, 64%, and 74%; and positive predictive values of 99%, 95%, and 83%. Conclusion: DUS is an optimal tool for quantification of SNS. However, a multisegment setting has a significant negative impact on the quantification of femoropopliteal artery stenosis.

Transluminal versus Subintimal Angioplasty for Management of Critical Limb Ischemia Patients with Femoropopliteal Occlusive Disease

Aim Comparison between intraluminal and subintimal angioplasty with review of technique, factors affecting the success and complications with special emphasis on factors that could predict the wire route meanwhile using simple techniques. Methods This is a non-randomized study with prospectively collected data that included 159 patients presented from 2011 to 2014 to the vascular surgery department with critical chronic lower limb ischemia due to atherosclerotic femoropopliteal occlusive disease for whom percutaneous angioplasty was done. Patients presenting with nonsalvageable limbs requiring primary major amputation and non-atherosclerotic causes of CLI were excluded. Results 75.5% of the lesionswere crossed transluminally while 19.5% of the lesions were crossed subintimally. In 8 cases (5%) the lesion could not be passed. The overall technical success to pass the lesion was 95%. On 24 months follow up, 1ry patency, 2ry patency, limb salvage in intraluminal group are 56.8%, 60.2% and 66.1% respectively while in subintimal group 46.7%, 46.7% and 60% respectively. Subintimal was more in the TASC D, lesion more than 10 cm and in contralateral access (P value was<0.05). There were no statistically significant differences between intraluminal and subintimal angioplasty regarding the outcome (Patency and limb salvage). Conclusions The passage of the wire is affected by length of the lesion, the TASC II classification of the lesion and access site with the subintimal passage was more in Lesion more than 10 cm, TASC D lesions and in contralateral access. These factors can be used prospectively as predictors for passage of the wire whether intraluminal or subintimal. In spite of the technical differences between the intraluminal and subintimal passage, yet they show no significant statistical differences regarding the outcome (patency and limb salvage). Hence both should be used as part of vascular armamentarium for revascularization in such frail patients.

Endovascular Treatment of Popliteal Artery Aneurism and Occlusive Arterial Disease-A case Report

There is no level A evidence to determine open repair (OR) or endovascular repair (ER) intervention to treat popliteal artery aneurisms. This article addresses a case of endovascular treatment of both popliteal artery aneurysm (PAA) and below knee peripheral atherosclerotic occlusive disease (PAD) in which we opted for endovascular treatment with satisfactory outcome, as well as a discussion about indications and expected results. We concluded that endovascular treatment is effective in treating this for it resolves the symptoms by recanalization of the artery system with little risks during the procedure and with short hospital stay.

Comparison of long-term results of above-the-knee femoro-popliteal bypass with autogenous vein and polytetrafluoroethylene grafts.

PurposeTo analyze the long-term results of above-the-knee femoro-popliteal bypass (ATKFPB) with vein grafts compared with polytetrafluoroethylene (PTFE) grafts.MethodsA database of patients with chronic atherosclerotic occlusive disease who underwent ATKFPB was retrospectively reviewed. Characteristics of patient and arterial lesion, and follow-up results were compared between vein grafts and PTFE grafts. Graft patency was determined by periodic examinations of duplex ultrasonography or CT angiograms. Graft patency and limb salvage rates were calculated using the Kaplan-Meier method.ResultsIn total, 253 ATKFPBs (107 vein grafts; 146 PTFE grafts; critical limb ischemia, 32%) were performed on 228 patients (mean age, 68.5 years; male, 87.7%). No significant differences were observed between the two groups with respect to demographic characteristics, characteristics of arterial lesions, or distal runoff score. During the mean follow-up period of 41 months (range, 1-122 months), 14.5% patients died, and 94% of all limbs were available for follow-up. The primary patency rates were not significantly different between the two groups at 10 years after treatment (75% vs. 42%, P = 0.330). However, the primary-assisted patency rates (88% vs. 42%, P = 0.003) and secondary patency rates (91% vs. 49%, P = 0.013) were significantly higher in the vein grafts compared with the PTFE grafts. Graft occlusion developed more often in the PTFE grafts (5.6% vs. 20.5%, P = 0.001). When graft occlusion occurred, acute limb ischemia was significantly more frequent in the PTFE grafts than in the vein grafts (0% vs. 53%, P = 0.027).ConclusionAfter ATKFPB, autologous vein grafts showed significantly better long-term results compared with PTFE grafts.

Age and disease-related geometric and structural remodeling of the carotid artery

Carotid artery geometry has been suggested as a risk factor for atherosclerotic carotid artery disease (ACD). Although normal aging and development of disease can both lead to geometric changes in the artery, whether geometric changes in a given artery actually predispose to disease or are just a consequence of remodeling during aging is unclear. We investigated carotid artery geometric changes with aging to identify geometric features associated with the presence of ACD. Carotid artery geometry was quantified by measuring carotid artery diameter, tortuosity, and bifurcation angle using three-dimensional reconstructions of thin-section computed tomography angiography scans in 15 healthy individuals (average age, 43 ± 18 years; range, 15-64 years). The same geometric features were measured in 17 patients (68 ± 10 years old) with unilateral ACD. Geometric features associated with presence of ACD were determined by using the nondiseased contralateral carotid artery as an intrinsic control. Elastin-stained carotid arteries were analyzed to assess age-related structural changes in 12 deceased individuals. Increases were noted in bulb diameter (0.64 mm), bifurcation angle (10°), and tortuosity of the common carotid (CCA; 0.03) and internal carotid arteries (ICA; 0.04) for every decade of life. Density and continuity of circumferential and longitudinal elastin in the CCA and ICA decreased with age. Compared with normal carotid arteries, those with ACD demonstrated larger bulb diameters (P = .001) but smaller bifurcation angles (P = .001). CCA tortuosity (P = .038) increased in ACD arteries compared with normal carotid arteries, but ICA tortuosity was decreased (P = .026). With increasing age, bulb diameter, tortuosity, and bifurcation angle increases in carotid arteries. These geometric changes may be related to degradation and fragmentation of intramural elastin. Arteries with atherosclerotic occlusive disease demonstrate decreased ICA tortuosity and smaller bifurcation angles compared with nondiseased carotid arteries.

A Radiolabeled PF-4 Staph-a Binding Assay Proposed As a Solitary Method for Confirming Heparin Induced Thrombocytopenia

Introduction:Heparin induced thrombocytopenia (HIT) is present in over 30% of normal subjects receiving heparin and the incidence of HIT may even be higher in patients with occlusive atherosclerotic disease. Confirmatory laboratory assays can broadly be classified as functional which have high specificity and rely on activation of platelets by the platelet factor 4 (FP4)-heparin-IgG immune complex or as immune based assays that are relatively more sensitive. At the time when the clinician is evaluating heparin as a cause of thrombocytopenia the 4 ”T” criteria are helpful. However, after the episode of decreased platelets is resolved, an increase in the patient’s platelet count is critical for confirmation of the diagnosis.Methods: We developed a variation of a previously described technique (Newman Thromb Haemost 1998;80:292) and used clinical criteria as the standard for comparison to evaluate the assay. Radiolabeled 125-I-PF4 is incorporated into the immune complex of PF-4-heparin-immunoglobulin and the amount of radiolabeled immune complex is measured after binding to Staphylococcal A Protein Sepharose. Our working hypothesis is that since this assay has both immune and binding components it would have better specificity and sensitivity than the currently used assays and as a single assay be more cost effective. The hospitalized subjects medical record was reviewed to; measure a 4 “T” score, to determine if the patient’s platelet count increased after heparin was stopped, to record the results of the hospitals’ assays for HIT and to ascertain what other causes of thrombocytopenia might be possible.Results: To date we have evaluated 20 samples. True positives were observed in 3 hospital patients and 4 known positives that were a gift from the Blood Center of S.E. Wisconsin. 10 true negatives included 5 from hospital patients and 5 from thrombocytopenic patients who were not treated with heparin. 3 samples were negative in our assay, had a 4 ”T” score of 6 and 5 and NA and had increased platelet counts after heparin was stopped and were judged as false negatives. However, these samples had high relative binding to the Staph-A-Sepharose in the sample without the addition of heparin suggesting that either the sample already had enough heparin from the patient’s treatment to form immune complexes or as has been recently reported another negatively charged molecule formed a complex with PF-4.(Warkentin Blood;2014;123:3651) Concordance between the radiolabeled PF-4 assay and the commercial PF-4 hospital assay was observed in 10 of 11 patients.Conclusions:To date when judged using clinical criteria, the radiolabeled PF-4 assay correctly distinguished true positives and true negatives in 17 of the 20 samples. This is an ongoing study with the goal of studying another 30 patients before the ASH December meeting. The addition of clinical criteria including the 4 “T” score and the increase in platelet count after stopping heparin to a review of the patient’s acute care hospital record is helpful in evaluating the reliability of the radiolabeled PF-4 assay as a predictor of HIT. DisclosuresNo relevant conflicts of interest to declare.