Normal LAD Research Articles

Abstract 17001: Enhancing Coronary Functional Angiography: Integrating Doppler-Based Left Circumflex Coronary Flow Reserve in Assessment

Background: Coronary microvascular dysfunction (CMD), predominantly affecting women is associated with poor outcomes and has limited diagnostic options. Coronary functional angiography (CFA) is used for diagnosing CMD in patients with refractory angina and no obstructive coronary artery disease (ANOCA). The assumption is that endothelial-independent CMD is a homogenous disease process, therefore current gold-standard for diagnosis is measure of coronary flow reserve (CFR) in the proximal left anterior descending artery (LAD). However, there is limited data on CFR in the left circumflex (LCx). Objective: Examine the benefits of measuring CFR using Doppler-tipped guide wire in LCx in addition to proximal LAD. Methods: Examined 191 ANOCA patients with Canadian Cardiovascular Society (CCS) class 3 or 4 angina despite optimal medical treatment who underwent CFA for assessment of CMD. CFR measurements were obtained using Doppler-tipped guidewire during the administration of 72 mcg of adenosine in both the proximal LAD and LCx and CFR of <2.5 was used to define CMD. Results: 191 patients underwent CFA including 91% female with a median age of 59 years (IQR: 50, 67). The correlation in CFR measurements between the proximal LAD and LCx was 0.610 (p<0.001). 149 (78%) patients had concordant results including 113 (59%) with abnormal CFRs and 36 (19%) with normal CFRs in both vessels. 12 (6%) had abnormal proximal LAD CFR and normal LCx CFR; and 30 (16%) had an abnormal LCx CFR and normal proximal LAD CFR and would have gone undiagnosed without measuring LCx CFR. Conclusion: The addition of LCx CFR measurement to the current standard CFA protocol using the Doppler guidewire improves diagnosis of CMD in patients. Further studies are needed to evaluate a comprehensive assessment of CMD including measurement of LCx CFR.

Left atrial remodelling after septal myectomy is associated with a reduced 5-year risk of atrial fibrillation in hypertrophic cardiomyopathy

Abstract Background Left atrial diameter (LAD) is an established predictor of atrial fibrillation (AF) and adverse outcomes in hypertrophic cardiomyopathy (HCM). However, the impact of LAD remodelling after surgical myectomy on the development of late onset AF is still poorly understood. Purpose To investigate the association between LAD remodelling and new occurrence of AF in the first five years after surgical myectomy in a large patient population with HCM. Methods 1177 HCM patients without a history of AF, subjected to surgical myectomy at two referral centres between 2001 and 2020 were retrospectively reviewed. Paired echocardiographic studies before and shortly after surgical myectomy were available in 894 (76%) patients and 889 (75%) patients had complete LAD measurements, defined as the anteroposterior diameter at end-systole from parasternal long axis view. LAD was considered normal when ≤40mm. Late onset AF was determined as AF documented between one month and 5 years follow up after myectomy. Patients were grouped as having normal LAD pre- and post-myectomy (group 1), enlarged pre-myectomy LAD but normal post-myectomy LAD (group 2), and those with enlarged LAD post-myectomy (group 3). Cox proportional hazards models were applied to evaluate the impact of LAD on late onset AF. Results Late onset AF was detected in 63 (7%) patients, 56% male, with an incidence of 1%/year. Patients with AF were older (56±13 vs. 52±14 years, p=0.03), had a larger post-surgery LAD (44±7 vs. 41±6 mm, p<0.001) and a lower left ventricular ejection fraction (58±6 vs. 61±6%, p=0.002) compared to patients without AF. Postoperative left ventricular maximal wall thickness (14±4 mm vs. 15±4mm, p=0.53), left ventricular outflow tract obstruction (6% vs. 8%, p=0.49) or moderate/severe mitral regurgitation (13% vs. 9%, p=0.29) were similar between patients with and without late onset AF. Among the 227 patients in group 1, late onset AF occurred in only 5 (3%), in comparison to 8 (5%) of 182 patients in group 2, and in 36 (10%) of the 480 patients in group 3 (p=0.006). Using group 1 as reference, the hazard ratio for developing AF was 2.1 (95% CI 0.7–6.5, p=0.15) for patients in group 2 and 3.5 (95% CI 1.4–9.4, p=0.005) for patients in group 3. Conclusion In our study we were able to show that the overall post-myectomy 5-year risk for developing AF was 1%/year. Normal LAD and reverse LAD remodelling correlated with a lower risk for developing late onset AF, whereas a higher risk was associated with enlarged post-myectomy LAD. These results highlight the possible clinical benefit of LAD remodelling after myectomy in reducing late onset AF. Funding Acknowledgement Type of funding sources: None.

Coronary artery perforation after bioresorbable scaffold implantation treated with a new generation covered stent\u2014OCT insights

BackgroundCoronary artery perforation is a rare but potentially lethal complication of percutaneous coronary intervention (PCI) with an associated mortality of 7–17%. We report the case of coronary artery perforation complicating Absorb bioresorbable vascular scaffold (BVS) implantation and the associated technical challenges with managing this life-threatening complication.Case reportA 46-year-old male was referred to our institution and underwent PCI with an Absorb bioabsorbable vascular scaffold (BVS) to a proximal LAD long segment bifurcation lesion. Following pre-dilation and deployment of the 3.5 × 28 mm Absorb BVS, high pressure post-dilation of the distal scaffold was complicated by a large, Ellis type III coronary perforation with no flow to the distal LAD beyond the rupture, and associated with a large pericardial effusion confirmed on bedside transthoracic echocardiogram (TTE). The insult was temporised with prolonged balloon inflation within the Absorb BVS immediately proximal to the site of perforation, permitting urgent insertion of a pericardial drain. After deflation of the balloon, a 3.0 × 21 mm BeGraft covered stent was deployed across the perforation, restoring normal LAD flow and abolishing the perforation. Cardio-pulmonary resuscitation was not required and the patient remained conscious throughout the procedure. TTE demonstrated normal left ventricular function and the patient was discharged 3 days later. Repeat angiography at 3 months showed patent stents with TIMI III flow, and optical coherence tomography (OCT) showed good expansion and apposition of the proximal Absorb BVS and BeGraft. The patient has remained well 4 years after PCI with no major cardiovascular events.ConclusionThe utility of bioresorbable scaffold technology remains controversial although meticulous implantation techniques are associated with improved clinical outcomes. Adoption of the Pre-dilatation, Sizing and Post-dilatation (‘PSP’) method of BVS implantation with routine aggressive vessel preparation and scaffold optimization however may contribute to a higher risk of vessel perforation. The case emphasises the importance of accurate sizing of the vessel with intracoronary imaging and demonstrates the value of newer generation covered stents with single-layer design and slimmer crossing profile producing improved deliverability and procedural success.

Thrombosis of Aberrant Right Subclavian Artery Presenting As Myocardial Infarction

Aberrant right subclavian artery (ARSA) is a rare anomaly, in which the right subclavian artery arises directly from the aortic arch instead of originating from the brachiocephalic artery. This anomaly should be taken into consideration during surgical procedures around the esophagus, such as esophagectomy. Any unintentional injury of this artery during surgical procedures could be extremely life-threatening. The patient was an 88-year-old male, known case of hypertension, CAD, COPD, presented with the chief complaint of chest pain for 2 days associated with the history of right-hand weakness and numbness for 1 week. ECG has done suggestive of Sinus Rhythm with LBBB Trop I – 6.1 ng/ml Coronary Angiography LMCA- Normal LAD- Mid LAD 80% stenosis LCX- Proximal 99-100% occluded RCA- normal CT ANGIO right upper limb done findings revealed anomalous retro esophageal course of right subclavian artery with narrowing at its origin and a small thrombus in juxta osteal segment. Thrombus of 6.7 cm long segment of the distal third of right brachial artery with the reformation of brachial artery at the level of elbow joint along with thrombosis of right ulnar artery at a short distance from its origin. Keywords: Aberrant right subclavian artery; Thrombosis; Myocardial infarction.

A Retrospective Dosimetric Analysis of the New ESTRO-ACROP Target Volume Delineation Guidelines for Postmastectomy Volumetric Modulated Arc Therapy After Implant-Based Immediate Breast Reconstruction.

Purpose: The European Society of Radiation & Oncology and Advisory Committee on Radiation Oncology Practice (ESTRO-ACROP) presented new guidelines for clinical target volume (CTV) delineation in post-mastectomy radiation therapy (PMRT) after implant-based immediate breast reconstruction (IBR-i). This study evaluated the dosimetric characteristics, dosimetric accuracy, and delivery accuracy of these guidelines in volumetric modulated arc therapy (VMAT).Methods and Materials: This retrospective study included 15 patients with left breast cancer who underwent mastectomy with tissue expander placement followed by PMRT. An experienced radiation oncologist delineated the CTV twice on the same image datasets based on the ESTRO-ACROP (EA-TVD) and conventional target volume delineation (C-TVD) guidelines. All VMAT plans, which used a double partial arc, were generated using six MV photons. Clinically relevant dose-volume parameters for organs at risk were compared. Dosimetric accuracy of the treatment plans and delivery accuracy were assessed.Results: Target volume of EA-TVD was significantly smaller than that of C-TVD. Although no statistically significant difference was noted in the target coverage between the two VMAT plans, EA-TVD VMAT significantly reduced the mean heart dose (3.99 ± 1.02 vs. 5.84 ± 1.78 Gy, p = 0.000), the maximum left anterior descending coronary artery (LAD) dose (9.43 ± 3.04 vs. 13.97 ± 6.04 Gy, p = 0.026), and the mean LAD dose (4.52 ± 1.31 vs. 6.35 ± 2.79 Gy, p = 0.028) compared with C-TVD VMAT. No significant difference was observed with respect to the total monitor units, plan complexity, and delivery quality assurance.Conclusions: This is the first study to show significant dose reduction for the normal heart and LAD tissue offered by the EA-TVD, while maintaining dosimetric and delivery accuracy, in PMRT after IBR-i in VMAT for left-sided breast cancer patients.

P961 Diagnostic use of proportion between ascending aorta and left atrium in patients referred for coronary artery calcium scoring

Abstract Background Non-contrast-enhanced cardiac computed tomography (NCE-CCT) is currently used for coronary artery calcium (CAC) scoring. Meanwhile, other cardiac, vascular and extra-cardiac structures can be evaluated. Data about ascending aorta (AA) and left atrium (LA) has been quantified separately in a few studies. Their mutual proportion has not been examined, as yet. Aim. We hypothesize that mutual proportion between AA and LA size might help for diagnosing their enlargement before absolute cut-off values are reached. Method Among 7950 patients who had NCE-CCT with a 64 raw scanner (Aquillion, Toshiba) within the last decade in our center, in 797 persons the AA diameter (at the level of pulmonary artery bifurcation) and LA diameter and area (highest value) were measured. Raw AAD values were qualified as abnormal if exceeded upper normal limit UNL) for age and height. Weight, BMI and BSA has not been used in order to avoid falsified results in obese patients. The ratio AAD:LAD was quantified as low (<0.8), normal (0.8-1.2) and high (>1.2). Results There were 45 patients (5.6%) who had AAD higher than age-height predicted UNL, including 24 patients with a raw AAD >43mm (3.0%). The other 752 has their AAD within limits. The means of AAD were 42.9 ± 3.2mm and 33.6 ± 3.6mm (p < 0.001). LA size differed significantly, both in diameters 38.5 ± 7.4 vs 34.2 ± 5.6mm (p < 0.001) and areas 2138 ± 593 vs 1837 ± 481 mm2 (p < 0.001). Data regarding mutual relationship are shown in the fig.1. It is seen that normal mutual proportion (AOLARel =1) in patients with high AAD means that LAD was also increased (left graph, red open square). In 603 patients with normal AAD corresponded with normal LAD. The AAD:LAD >1.2 in 845 subjects might suggest increased AAD in spite to normal raw diameter. Similar rules were found in respect to the LA area. Conclusions Ascending aorta and left atrium enlargement are infrequently recognized in patients referred to CAC scoring. Mutual proportion between AA and LA size might complement diagnostic approach of their abnormalities.

Distribution of pressure gradients along the left anterior descending artery in patients with angiographically normal arteries.

This study tested the hypothesis that there is no decline of coronary pressure from the proximal to the distal left anterior descending coronary artery (LAD) of humans and swine. In the daily clinical practice, the fractional flow reserve (FFR) in the LAD is frequently lower than that in the other arteries in the presence of a similar degree of stenosis. Twenty-six patients with angiographically normal LAD were prospectively enrolled. The coronary pressure ratio (mean distal/proximal coronary pressures at hyperemia) was measured at five different positions: 12, 10, 7, and 5 cm distal from the LAD ostium, and at the ostium of the LAD. The coronary pressure measurement was further investigated in a swine model without atherosclerosis. The coronary pressure ratio during maximum hyperemia gradually decreased in proportion to the distance from the ostium (average: 0.85 ± 0.06 at 12 cm distal to the ostium). This finding was confirmed in swine model. The degree of the coronary pressure decrease during maximum hyperemia was similar in patients with and without evidence of minor plaque on intravascular ultrasound, however it was strongly associated with the amount of myocardium mass in the territory of the LAD. Intracoronary pressure gradually decreases in proportion to the distance from the ostium in the LAD of humans and swine, regardless of the presence of minor atherosclerotic plaques. The degradation degree of the coronary pressure ratio during maximum hyperemia is enlarged in the presence of larger amount of myocardium mass in the territory of the LAD.

The Prognostic Value of Coronary Flow Velocity Reserve in Two Coronary Arteries During Vasodilator Stress Echocardiography

Vasodilator stress echocardiography (SE) allows combined evaluation of regional wall motion and Doppler coronary flow velocity reserve (CFVR) of both the left anterior descending coronary artery (LAD) and the right coronary artery (RCA). The aim of this study was to prospectively assess the prognostic correlates of LAD and RCA CFVR on SE. A total of 1,365 patients with known or suspected coronary artery disease underwent dipyridamole SE with combined evaluation of CFVR in both the LAD and the RCA. Ischemia was present on SE in 263 patients (19%). CFVR was abnormal (≤2.0) in 545 patients (40%): 172 in the LAD only, 149 in the RCA only, and 224 in both the LAD and the RCA. During a median follow-up period of 20months, 44 deaths and 98 myocardial infarctions occurred. In the overall population, LAD CFVR ≤ 2.0 (hazard ratio [HR], 3.93) and inducible ischemia (HR, 2.74) were multivariate prognostic predictors. In the subset with ischemia on SE, CFVR did not add to peak wall motion score index (HR, 2.23). In patients without ischemia on SE, age (HR, 1.04), anti-ischemic therapy at the time of testing (HR, 1.6) and LAD CFVR≤2.0 (HR, 10.8) were independent prognostic indicators. In patients without ischemia on SE and LAD CFVR >2.0, the 4-year event rate was 4% in those with RCA CFVR > 2.0 and 18% in those with RCA CFVR ≤ 2.0 (P<.0001). Ischemia on SE with high peak wall motion score index identifies a high-risk subset regardless of the underlying CFVR response. Absence of ischemia on SE is associated with intermediate risk, and LAD CFVR is essential to identify a truly low-risk subset. RCA CFVR is less useful than LAD CFVR but may have a role for further risk stratification in patients without ischemia and normal LAD CFVR.

Do we need three coronary arteries?

Normal myocardium is usually perfused by three coronary arteries- a left main system bifurcating into left anterior descending artery (LAD), and left circumflex artery (LCx), and right coronary artery (RCA). Coronary artery anomalies are congenital changes in their origin, course, and/or structure, which are usually discovered as incidental findings during coronary angiographic studies. Here, we report a case of 56-year-old hypertensive, and diabetic male who was being evaluated for exertional angina and dyspnoea whose coronary angiogram revealed a rare coronary anomaly: normal LAD, absent LCx, and superdominant RCA which was better delineated on Multidetector coronary angiography (MDCT). Multislice CT is the non-invasive modality of choice for imaging anomalies of coronary arteries and provides high speed with excellent spatial resolution.

Abstract 18858: Assessment of Coronary Artery Aneurysms Caused by Kawasaki Disease Using Transluminal Attenuation Gradient Analysis of Coronary CT Angiograms

Introduction: Patients with coronary artery aneurysms (CAA) resulting from Kawasaki Disease (KD) are at risk for thrombosis and myocardial infarction. Current guidelines recommend using CAA diameter &gt;8mm as the criterion for initiating systemic anticoagulation, but this is not based on outcome or simulation data. Transluminal Attenuation Gradient (TAG) has been proposed as a non-invasive method for evaluating the functional significance of coronary stenoses from CT Angiography (CTA). However TAG has not been previously used for the assessment of CAA. Hypothesis: We hypothesized that abnormal flow conditions in CAA caused by KD could be quantified using TAG. Methods: We studied 23 patients with a history of KD who had undergone clinically indicated CTA. We quantified TAG in the major coronary arteries by performing linear regression of the average lumen intensity as a function of vessel length. Aneurysm geometry was characterized using maximum aneurysm diameter, aneurysm shape index (ASI) and sphericity index. Results: A total of 41 arteries were analyzed, 22 of which had at least one aneurysmal region. TAG of aneurysmal arteries was significantly lower than in normal arteries (-22.4±10.5 vs. -9.3±10, p=0.0003). Differences were also significant in aneurysmal vs. normal LAD and RCA sub-groups (-26.7±9.7 vs. -16.5±9.0, p=0.02; -14.7±8.2 vs. -0.1±4.4, p=0.001). Aneurysm diameter, ASI, and sphericity index showed little to no correlation with TAG (r2=0.04, r2=0.18, r2=0.17). Conclusions: This study is the first application of TAG in CAA from KD, and demonstrates significantly different TAG values in aneurysmal compared to normal arteries. Lack of correlation between TAG and CAA geometry suggests that TAG may provide information on hemodynamic conditions not available from anatomy alone. The use of TAG in KD patients represents a possible extension to standard CTA that could aid in clinical decision-making and help to better evaluate the risk of thrombus formation.

Elevated Serum Tryptase and Endothelin in Patients with ST Segment Elevation Myocardial Infarction: Preliminary Report.

An inflammatory response plays a crucial role in myocardial damage after an acute myocardial infarction. Objectives. To measure serum concentrations of several mediators in patients with an acute myocardial infarction (STEMI) and to assess their potential relationship with a risk of coronary instability. Patients and Methods. The 33 patients with STEMI and 19 healthy volunteers were analyzed. The clinical data were obtained; as well serum concentrations of tryptase, endothelin (ET-1), angiogenin, soluble c-kit, and PDGF were measured. Results. Patients with STEMI had higher serum tryptase and ET-1 than healthy volunteers (2,5 ± 0,4 ng/mL versus 1,1 ± 0,4 ng/mL and 0,7 ± 0,1 ng/mL versus 0,3 ± 0,1 ng/mL, resp.). Subjects with significant lesion in left anterior descending artery (LAD) had lower serum ET-1 compared to those with normal LAD (0,6 ± 0,2 pg/mL versus 0,9 ± 0,4 pg/mL). Patients with three-vessel coronary artery disease (CAD) had higher level of soluble c-kit compared to those with one- or two-vessel CAD: 19,9 ± 24,1 ng/mL versus 5,6 ± 1,9 ng/mL. Conclusions. Elevated serum tryptase and ET-1 may be markers of increased coronary instability; some cytokines may be related to the extension of CAD.

Transthoracic measurement of left coronary artery flow reserve improves the diagnostic value of routine dipyridamole-atropine stress echocardiogram

IntroductionWe hypothesized that coronary flow reserve (CFR) in the left anterior descending artery (LAD) can be effectively measured during an accelerated dipyridamole-atropine stress echocardiography (DASE) protocol to improve the diagnostic performance of the test.Material and methodsIn 64 patients with suspected or known coronary artery disease scheduled for coronary angiography DASE with concomitant CFR measurement in LAD was performed.ResultsCoronary flow reserve measurement and calculation were feasible in 83% of patients. The positive predictive value of undetectable LAD flow was 81% for severe LAD disease. Measured values of CFR were in the range 1.3–4.1 (mean: 2.2 ±0.7). Significantly lower CFR was found in patients with LAD disease (1.97 ±0.62 vs. 2.55 ±0.57, p = 0.0015). The optimal cutoff for detecting ≥ 50% stenosis was CFR ≤ 2.1 (ROC AUC 0.776), corresponding with 68% sensitivity and 84% specificity. In patients with negative DASE results 67% of patients with LAD disease had abnormal CFR, whereas in patients with a positive DASE result 92% of patients with normal LAD had normal CFR. The DASE diagnostic accuracy for the detection of coronary artery disease (CAD) increased from 75% to 85% when CFR measurement was added to wall motion abnormality (WMA) analysis. No test with both abnormalities was false positive for the detection of coronary disease.ConclusionsIncorporation of CFR measurement into WMA-based stress echocardiography is feasible even in an accelerated DASE protocol and can be translated into an approximate gain of 10% in overall test accuracy.

ASSESSMENT OF THE LEFT ATRIAL FUNCTION INDEX BY ECHOCARDIOGRAPHY IN THE EVALUATION OF LEFT HEART FUNCTION IN PATIENTS WITH ESSENTIAL HYPERTENSION

ObjectivesTo evaluate the left atrial function with the left atrial function index in patients with essentienal hypertension using echocardiography.MethodsSixty hypertensive patients and 31 normal controls were selected. The high, weight,...

Severe Aortic Regurgitation After Transradial Percutaneous Coronary Intervention

A 60-year-old man presented to a community hospital with new-onset shortness of breath after a 2-hour episode of typical chest pain. The ECG showed anteroseptal and inferior wall Q-waves. Serum troponin T levels were negative. An echocardiogram revealed anterior wall hypokinesia with left ventricular ejection fraction of 40% and no signs of valvular disease. The patient was transferred to our center for coronary angiography. Arterial access was obtained from the right radial artery. The angiogram showed mild disease of the left coronary artery and a right coronary artery (RCA) arising from the left coronary sinus. The RCA was extremely difficult to cannulate; nonselective injections revealed a long and severe stenosis of the mid segment (Figure 1 and Movie 1). After many unsuccessful attempts to cannulate the RCA with different guiding catheters, the operator decided to engage first the left coronary artery with an Amplatz 2 guiding catheter. A BMW Universal II guide wire was advanced into the left anterior descending artery (LAD) for better stability. This approach …

Detection of severe left anterior descending coronary artery stenosis by transthoracic evaluation of resting coronary flow velocity dynamics

In the presence of severe stenosis, coronary artery flow may be reduced at rest. Recent advances in echocardiography have made non-invasive sampling of velocities in the left anterior descending coronary artery (LAD) possible. The aim of our study was to evaluate feasibility and capability of transthoracic Doppler to detect severe stenosis of the LAD. The study population consisted of 42 subjects with suspected coronary artery disease scheduled for coronary angiography. All had complete transthoracic echocardiography and Doppler sampling of LAD velocities. Quantitative coronary angiography was performed within 24 hours of the echocardiogram. Correlations between LAD velocity profile, measurements and calculations, and the angiographic results were performed. Six subjects had LAD occlusion, 10 had severe (>80% diameter) LAD stenosis, and 26 had normal or non-occlusive LAD disease. In all six subjects with LAD occlusion, distal LAD velocities were not detectable, while in the other 36 subjects, LAD velocities were recorded indicating the vessels were patent. In the 10 subjects with severe LAD stenosis, the diastolic/systolic velocity ratio was <1.5, while in those with non-significant LAD disease, the diastolic/systolic velocity ratio was >1.5 (P<0.005). Diastolic LAD flow was 21.8±13 mL/min in the presence of severe stenosis as compared to 48.5±20 mL/min in subjects without severe stenosis (P<0.0013). LAD velocities had high sensitivity and specificity for the prediction of severe angiographic stenosis. Thus transthoracic Doppler measurement of LAD velocities is feasible and can predict the presence of severe LAD stenosis or occlusion.

Prospective Evaluation of Pre and Postoperative Lymphoscintigraphy in Axillary Reverse Mapping (ARM) for Breast Cancer Patients.

Abstract BackgroundThe sentinel lymph node (SLN) procedure, has been used successfully to detect lymphatic involvement. The expected reduction in morbidity and improvement in the quality of life of patients remains uncertain. In spite of this minimal invasive technique, 40 to 50 % of axilla are explored by classic axillary dissection. The aim of axillary reverse mapping (ARM) is to preserve the main lymphatic chain in relation to lymphatic arm drainage during an axillary dissection, reducing the rate of lymphedema.ObjectivesThe objective of this study is to describe a prospective comparison of pre and post axillary dissection (AD) lymphoscintigraphy, in 15 consecutive breast cancer patients.MethodsIsotope InjectionThe morning of surgery, all patients underwent isotope injection in the ipsilateral hand. Each patients received a single injection of 60 MBq (vol 0.2 ml) into the first interdigital space. The preoperative lymphoscintigraphy was performed 45 min after injection, in surgical position. An average of 2 nodes were visible in the axilla. The postoperative lymphoscintigraphy was planned before starting adjuvant treatment.Surgical TechniqueAfter having performed the lumpectomy or the mastectomy, the surgeon began the AD. The first important step was the identification of the second intercostals brachial nerve. While reserving the nerve, the dissection was carried out from medial to lateral, below the nerve. The gamma probe was then used in order to identify the first radioactive node draining the upper limb. This node was localized in the lateral pillar of the axilla. The ARM nodes were carefully preserved during the dissection with retractors placed over them to protect from inadvertent damage. After completion of AD, the axillary content was examined ex-vivo to identify at least ten nodes within the surgical specimen.ResultsThe mean age is 62.4 years (range 40-81). For all 15 patients, the mean number of axillary nodes removed by means of AD was 10.7 (range 7–14). Of all patients, 3 (87%) had metastatic involvement in the AD with an average of 1.3 (range 1– 2) nodes involved.A lymphoscintigraphic mapping concordance between pre and post, was found in 13 out 15 patients (87%).ConclusionsIsotopic ARM allows identification of radioactive nodes in the axilla in 91% of cases.The very good correlation between pre and postoperative mapping suggests a persistence of the normal LAD, and lets hope for a risk reduction of lymphodema after AD.A longterm follow up is needed to confirm these very promising preliminary results. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1025.

139 Determination of myocardial OEF with a CMR method in a stenotic dog study

Methods Thirteen dogs were divided into four groups (Table 1). Stenosis was created by using an occluder in the proximal left anterior descending coronary artery (LAD) in an open-chest model. Single-slice T2-weighted images were gathered by use of a 2-D segmented turbo spin-echo (TSE) sequence with double inversion recovery pulses. T2 maps can be generated with these T2-weighted images with different TE’s acquired in a single breathhold. This T2-imaging was performed several times during rest and during either Dipyridamole or Dobutamineinduced hyperemia. Using a two-compartment model validated in normal dogs [1], the OEF during hyperemia can be determined assuming resting OEF of 0.6, which is based on OEF values measured in normal dogs using an arterial and coronary sinus blood sampling approach at rest [3]. It is assumed that this value changes little with moderate stenosis [4], but for severe stenoses, this may be a potential source of error. The model also requires input of MBV values both at rest and during pharmaceutical hyperemia. These values were determined with a validated first-pass perfusion cardiovascular magnetic resonance (CMR) method [4]. OEF values were determined in the stenotic LAD region and a remote normal left-circumflex (LCX) subtended region. Results There is no significant change in OEF values calculated using assumed MBV and MBV measured with the quantitative CMR first-pass method. Nevertheless, the former slightly overestimated the later (0.3% in LAD-perfused and 5.8% in LCX-perfused regions) (Figure 1). This difference may explain why the former method slightly overestimated the “true” OEF values measured in normal dogs using the arterial-venous blood sampling approach [1]. The changes in OEF with measured MBV are shown in Figure 2. With the injection of Dipyridamole, while normal LAD region demonstrates reduced OEF of 0.31 (48% reduction), OEF in the LAD region changes to 0.54 (11% decrease) and 0.6 (0% change) in dogs with 70% and 90% stenosis, respectively. During the Dobutamine-induced hyperemia, dogs with stenosis had slight changes in OEF in the LAD region, but an increase to 0.69 (14% increase) and decrease to 0.46 (23%) in the LCX region with 50% and 70–90% stenosis, respectively (P = NS). This is consistent with our previous observation [2].

Multislice CT coronary angiography for the detection of burden, morphology and distribution of atherosclerotic plaques in the left main bifurcation

The aim of the study was to explore the differences in plaque burden at different segments of the left main bifurcation and its relationship with the bifurcation angle using high-resolution multislice CT coronary angiography (MSCT). Patients were evaluated using a 40-row MSCT scanner. One observer assessed the localization, severity and distribution of plaques within the left main (LMCA) bifurcation, whereas another observer defined the angle. Fifty patients were included. The mean heart rate was 59.8 +/- 7.1. Seventeen (34%) patients presented at least wall irregularities in the LMCA and in the ostial LCx, whereas the ostial LAD was affected in 32 (64%) patients. More than 90% of plaques were located opposite to the flow divider. The median bifurcation angle was 88.5 degrees (IQR 68.8 degrees, 101.4 degrees). Of the 18 patients with a normal ostial LAD, 13 (72%) had a bifurcation angle < 88.5 degrees , whereas the 63% of the patients with any LAD disease had an angle >or= 88.5 degrees (P = 0.018). In conclusion, at the left main bifurcation, atherosclerotic plaques are commonly located at the ostial LAD and opposite to the flow divider. The angle of the left main bifurcation and the presence of plaques within the bifurcation are closely related.

Computational stress-deformation analysis of arterial walls including high-pressure response

Background Changes in the mechanical behavior of arteries after balloon angioplasty cause cell reactions that may be responsible for restenosis. Hence, the study of the stress-deformation changes in arterial walls following supraphysiological tissue loading is an essential task. Methods A normal LAD coronary artery was modeled and computationally analyzed as a two-layer, thick-walled, anisotropic and inelastic circular tube including residual strains. Each layer was treated as a fibre-matrix composite. The tube was subjected to an axial stretch of 1.1 and a transmural pressure of 750 mm Hg. Since overstretch of remnant non-diseased tissue in lesions is a primary mechanism of lumen enlargement this model approach represents a reasonable first step. Results At physiological loading, the residual stresses led to a significant reduction of the high circumferential stress values at the inner wall, and the stress gradients. At low pressure level the media was the mechanically relevant layer, while at supraphysiological loading, the adventitia was the predominant load-carrying constituent providing a stiff support for ‘redistribution’ of soft plaque components by means of radial compression. After unloading to physiological loading conditions the stress state in the arterial wall differed significantly from that before inflation; the stress gradient in the media even changed its sign. Complete unloading indicated lumen enlargement, material softening and energy dissipation, which is in agreement with experimental studies. Conclusions This method may be useful to improve interventional protocols for reducing the dilatational trauma, and thereby the adverse biological reaction in arterial walls following balloon angioplasty.

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