Shinichi Iwakoshi

Clinical outcomes of thoracic endovascular aneurysm repair using commercially available fenestrated stent graft (Najuta endograft)

OBJECTIVE Thoracic endovascular aneurysm repair (TEVAR) for the aortic arch aneurysm is challenging because of its curved anatomic configuration and the presence of the supra-aortic branches. The Najuta fenestrated endograft (Kawasumi Laboratories, Inc, Tokyo, Japan) was developed to treat aortic arch diseases, offering maximal proximal landing length while preserving the blood flow to the supra-aortic branches. We evaluated the perioperative and midterm outcomes of this fenestrated endograft. METHODS Between July 2007 and July 2013, 32 patients were treated with the Najuta endograft at three vascular centers. The mean age of the patients was 74.5 ± 9.8 years (23 patients were men). Technical success, complication, overall survival rate, freedom from aneurysm-related death, secondary intervention, aneurysm enlargement, device migration, and patency of supra-aortic branches were investigated retrospectively. RESULTS The median follow-up period was 2.5 years (range, 0.2-6.2 years). Seventy-one supra-aortic vessels (30 brachiocephalic arteries, 31 left common carotid arteries, 10 left subclavian arteries) were planned to be preserved with fenestrations. Technical success rate was 91% (29 of 32; three type I endoleaks were seen), and five perioperative complications (two Stanford A dissections, one cerebral infarction, one celiac artery obstruction, one spinal cord ischemia) were recognized. Perioperative death was not observed. Overall survival rate and rate of freedom from aneurysm-related death at 3 years were 67% and 97%, respectively. The rate of freedom from secondary intervention and the rate of freedom from aneurysm enlargement at 3 years were 84% and 85%, respectively. Device migration was not observed. There were two branch (left carotid artery and left subclavian artery) occlusions at 2 weeks after TEVAR due to the endografts infolding. No other branch occlusion was seen in this follow-up period. As a result, the patency rate of the supra-aortic branch was 97% at 3 years. CONCLUSIONS The perioperative and 3-year outcomes of TEVAR using the Najuta precurved, fenestrated endograft demonstrated high freedom from aneurysm enlargement and patency rates of the supra-aortic branches.

Preliminary experience with superparamagnetic iron oxide-enhanced dynamic magnetic resonance imaging and comparison with contrast-enhanced computed tomography in endoleak detection after endovascular aneurysm repair

OBJECTIVE Contrast-enhanced computed tomography (CE-CT) has been commonly used for follow-up imaging after endovascular aneurysm repair (EVAR), but it is difficult to use on patients with renal insufficiency. Superparamagnetic iron oxide (SPIO) particles, contrast medium for magnetic resonance imaging (MRI) that has been widely used for detection of the liver tumor, rarely affects renal function. The present study examined SPIO-enhanced dynamic MRI as a potential alternative to CE-CT for detection of endoleaks after EVAR. METHODS Institutional review board approval was obtained for this prospective study. Twenty-three consecutive patients with normal renal function were evaluated using both CE-CT and SPIO-enhanced MRI within 2 weeks after EVAR. The median interval between the two modalities was 2 days. SPIO-enhanced MRI was performed at 1.5 T with T1-weighted, SPIO-enhanced dynamic, and postcontrast T1-weighted gradient echo sequences. The CE-CT protocol consisted of triple scans. Two experienced, blinded observers evaluated all images. Consensus reading of CE-CT and SPIO-MRI was defined as the reference standard. Interobserver, intraobserver, and intermodality agreement for endoleak detection was assessed by κ statistics. RESULTS A total of 11 type II endoleaks originating from either the lumbar or inferior mesenteric artery were detected. Eight were able to be detected by CE-CT (8/11:73%) and 10 (10/11:91%) by SPIO-enhanced MRI. Interobserver (κ = 0.91; 95% CI, 0.74-1.00) and intraobserver agreement for MRI (κ = 1.00) were excellent. Intermodality agreement for endoleak detection was moderate (κ = 0.63; 95% CI, 0.32-0.94; and κ = 0.62; 95% CI, 0.29-0.95 for observers A and B, respectively). CONCLUSIONS SPIO-enhanced MRI could represent a useful alternative to CE-CT, as it offers excellent interobserver, intraobserver agreement, and could detect more endoleaks than CE-CT.

Validation study of automated oscillometric measurement of the ankle-brachial index for lower arterial occlusive disease by comparison with computed tomography angiography.

The ankle-brachial index (ABI) determined by the oscillometric method has been shown to reliably detect peripheral arterial disease (PAD), with highly correlations with the Doppler method. However, most of these studies were shown in cohorts with a small number of PAD patients, and no imaging studies have been performed. The purpose of this study is to evaluate the diagnostic accuracy and optimal threshold of oscillometric ABI for detecting PAD using computed tomography angiography (CTA) as a gold standard in a cohort that consists mostly of PAD patients. This retrospective study included 108 consecutive patients with 216 limbs. ABI measured by an oscillometric device was compared with CTA. The diagnostic accuracy of oscillometric ABI to detect ⩾50% and ⩾75% stenosis confirmed by CTA and the optimal ABI cutoff values were evaluated using receiver operating characteristic (ROC) curve analysis. The oscillometric ABI could not be measured in nine limbs. The mean ABI was 0.72±0.31. The areas under the ROC curves (AUCs) for detecting ⩾50% and ⩾75% stenosis with oscillometric ABI were 0.919 and 0.918, respectively. The optimal ABI cutoff values to detect these levels of stenosis were 0.99 (sensitivity, 90%: specificity, 85%) and 0.87 (sensitivity, 84%: specificity, 89%), respectively. If patients with diabetes mellitus (DM) were analyzed separately, the AUC for detecting ⩾75% stenosis was 0.888. Oscillometric ABI had a high diagnostic accuracy to detect PAD using CTA as a gold standard. The diagnostic ability of ABI to detect PAD could be impaired by the presence of DM.

Technique of Percutaneous Direct Needle Puncture of Calcified Plaque in the Superficial Femoral Artery or Tibial Artery to Facilitate Balloon Catheter Passage and Balloon Dilation of Calcified Lesions

Heavy calcified arterial lesions are challenging to endovascular treatment. Even if a guide wire passes the lesion, calcified plaque can inhibit passage or dilation of the balloon catheter. We developed a novel technique of percutaneous direct needle puncture of calcified plaque (PIERCE) to allow subsequent passage and dilation of the balloon. PIERCE was performed in three patients with superficial femoral artery (SFA) lesions and one patient with a tibial artery lesion. In all four cases, balloon passage and lesion dilatation were achieved. Minor hemorrhage from the punctured site occurred in two patients with SFA lesions, which resolved with stent placement.

A Decade of Outcomes and Predictors of Sac Enlargement after Endovascular Abdominal Aortic Aneurysm Repair Using Zenith Endografts in a Japanese Population

PURPOSE To present 10-year outcomes and risk factors for sac enlargement after endovascular aneurysm repair (EVAR) using the Zenith AAA Endovascular Graft (Cook, Inc, Bloomington, Indiana) in a Japanese population. MATERIAL AND METHODS During the period 1999-2011, 127 patients underwent elective EVAR using Zenith endografts at a single institution. A retrospective investigation looked at initial rates of technical success and complications, 10-year rate of freedom from all-cause and aneurysm-related mortality, freedom from secondary intervention and sac enlargement, and risk factors for second intervention and sac enlargement. RESULTS The median age of the patients was 78 years, and the median follow-up time was 43 months. The initial technical success rate was 98.4% (125 of 127 patients). Major adverse events occurred in 7 of 127 (5.5%) patients. Rates of freedom from all-cause and aneurysm-related mortality at 1, 3, 5, and 10 years were 95%, 87%, 77%, and 39% (all-cause mortality) and 100%, 100%, 99%, and 93% (aneurysm-related mortality). Rates of freedom from secondary intervention at 1, 3, 5, and 10 years were 97%, 91%, 88%, and 70%. Rates of primary freedom from sac enlargement at 1, 3, 5, and 10 years were 99%, 87%, 75%, and 67%. Multivariate analysis revealed aneurysm sac diameter as an independent risk factor for a secondary intervention. Preoperative sac diameter combined with an angulated short (AS) proximal neck was a risk factor for sac enlargement. CONCLUSIONS The 10-year results of EVAR using Zenith endografts in a Japanese population were comparable to results from Western countries. Larger aneurysms and AS neck were predictors of sac enlargement after EVAR.

Combination of pulse volume recording (PVR) parameters and ankle-brachial index (ABI) improves diagnostic accuracy for peripheral arterial disease compared with ABI alone.

The ankle–brachial index (ABI) measurement is widely used as a screening tool to detect peripheral arterial disease (PAD). With the advent of the oscillometric ABI device incorporating a system for the measurement of pulse volume recording (PVR), not only ABI but also other parameters, such as the percentage of mean arterial pressure (%MAP) and the upstroke time (UT), can be obtained automatically. The purpose of the present study was to compare the diagnostic accuracy for PAD with ABI alone with that of a combination of ABI, %MAP and UT. This study included 108 consecutive patients on whom 216 limb measurements were performed. The sensitivity, specificity and positive and negative predictive values of ABI, %MAP, UT and their combination were evaluated and compared with CT angiography that was used as a gold standard for the detection of PAD. The diagnostic accuracy as well as the optimal cutoff values of %MAP and UT were evaluated using receiver operating characteristic (ROC) curve analysis. The combination of ABI, %MAP and UT achieved higher sensitivity, negative predictive value and accuracy than ABI alone, particularly for mild stenosis. The areas under the ROC curve for the detection of 50% stenosis with UT and %MAP were 0.798 and 0.916, respectively. The optimal UT and %MAP values to detect ≧50% stenosis artery were 183 ms and 45%, respectively. The combination of ABI, %MAP and UT contributed to the improvement of the diagnostic accuracy for PAD. Consideration of the values of %MAP and UT in addition to ABI may have a significant impact on the detection of early PAD lesions.

Technical tips and procedural steps in endovascular aortic aneurysm repair with concomitant recanalization of iliac artery occlusions

PurposeThe goal of this paper is to describe our technical strategy and procedural steps for endovascular aneurysm repair (EVAR) when performed with concomitant recanalization of the iliac artery occlusion.Materials and methodsThree octogenarians having abdominal aortic aneurysm (AAA)/common iliac artery aneurysms (CIAA) with unilateral external iliac artery (EIA) occlusion underwent EVAR with recanalization of the occluded iliac arteries. Crossing the iliac artery occlusions was attempted in a retrograde approach using a 0.035 inch-hydrophilic guidewire. After passage of a guidewire, predilation was performed using 6mm balloon. Then a 12-Fr sheath was advanced via the occluded EIA for contralateral iliac limb delivery. Internal iliac artery embolization was subsequently performed as needed. A self-expanding stent was then placed in the occluded EIA after EVAR.ResultsRecanalization of the EIA occlusion, followed by stentgraft delivery through the occlusion and EVAR, was successfully performed in all three patients. Penetration of the occluded EIA was successfully achieved only by retrograde approach in two patients, and by bidirectional approach in the other patient. No perioperative complication or death occurred. Postoperative CT showed no type I or III endoleaks in the aneurysms and patent iliac arteries in all patients.ConclusionsTotal endovascular repairs were successfully performed for three patients with AAA and concomitant unilateral EIA occlusions. The proposed steps described in this report might reduce the complication rate and enhance the technical success rate associated with this procedure.

Measuring the greater curvature length of virtual stent graft can provide accurate prediction of stent graft position for thoracic endovascular aortic repair

Objective The objective of this study was to assess the accuracy of predicting stent graft position for thoracic endovascular aortic repair by measuring three lengths of the virtual stent graft: smaller curvature (SC), center lumen line (CL), and greater curvature (GC). Methods From January 2012 to December 2016, patients treated at our institution were analyzed retrospectively. Patients who were treated with more than two devices, patients treated for aortic dissection, and cases without complete preoperative or postoperative computed tomography (CT) data were excluded. From the preoperative CT data, the virtual stent graft image based on the SC (SCVS) was created so that its SC length matched that of the stent graft actually used. In the same manner, virtual stent graft images based on the CL (CLVS) and GC (GCVS) were created. These virtual stent graft images were created using SYNAPSE VINCENT software (Fujifilm Co, Tokyo, Japan) and superimposed on the postoperative CT image to measure the misalignment between these virtual stent graft images and the actual stent graft. These misalignments were compared using Wilcoxon signed rank sum test. In addition, the actual length (AL) of the stent graft was measured on the basis of the CL from postoperative CT data and compared with its original length (OL). Results A total of 35 cases were analyzed. Twenty‐six patients were men. The average age of the patients was 72.4 ± 13.0 years. The proximal landing zone were located at the descending aorta (n = 11) and the aortic arch (n = 24). The misalignment between SCVS, CLVS, and GCVS and actual stent graft position was −47.8 ± 18.1 mm, −21.5 ± 9.4 mm, and 5.3 ± 7.4 mm, respectively. The difference in means between the three groups was significant (P < .001). The relationship between the AL based on CL and OL was represented by the formula AL = OL * 0.92 − 0.05 (in the descending aorta) and AL = OL * 0.77 + 9.85 (in the aortic arch). Conclusions Compared with CLVS and SCVS, GCVS was the most accurate predictor of stent graft position for thoracic endovascular aortic repair.

Preliminary Evaluation of Aortic Aneurysm Screening Using Oscillometric Device Equipped With Novel Algorithm Analyzing Pulse Wave Transfer

BACKGROUND Detection of aortic aneurysm (AA) prior to rupture is crucial to decreasing its mortality. Towards this purpose, a novel detection algorithm was developed from pulse volume recording (PVR), analyzing the propagation loss of pulse waves caused by expansion of the aortic wall. The diagnostic ability of the algorithm was evaluated in this prospective study.Methods and Results:PVR were measured for 30 s using the oscillometric device designed for automatic measurement of the ankle-brachial index (ABI). The algorithm processed the data automatically and assessed whether the patient had an AA. CT angiography was used as the reference standard. Sensitivity and specificity of the algorithm were evaluated. A total of 152 AA patients, including 21 patients with thoracic AAs (TAA), and 64 non-aneurysm control subjects were enrolled. The mean diameter of all AAs was 47.2±10.3 mm. After measurements, 121 AA patients and 33 control subjects were judged by the algorithm as having or not having AAs, resulting in sensitivity of 80% and specificity of 52%. The sensitivity was higher for larger AAs. There was no sensitivity difference according to the location of the AA. CONCLUSIONS The new diagnostic algorithm installed in the oscillometric device detected AAs with high sensitivity, especially larger aneurysms. For application as a screening tool, the specificity needs to be improved.