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`
`Heart and Vessels
`
`Volume 21 Number1 January 2006
`
`Q 3mm;
`
`PROPERTY OF THE
`§ :4
`WIN NATIONAL
`LIBRARY or a
`_—n MEDICINE
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`Heart
`Vesse
`
`W
`
`Volume 21 Number 1
`
`January 2006
`
`Original articles
`
`I Clinical investigation
`
`J. Yokoyama, M, Kushibikl, T Fuiiwara Y, Tamura. N. Maeda.
`i. Higuma, 5. Sasaki, I’. Yoshlmacni, T. Matsunaga. H Hanada.
`T. Osanai, K. Okumura
`Feasibility and safety of thrombectomy with TVAc aspiration
`catheter system for patients with acute myocardial
`infarction
`1
`
`B Amasyali S. Kr'jse. K. Aytemir. I. Can. G Kabakci, L. Tokgozoglu.
`H. Ozkuzlu. N. Nazli, E. Isik. A. Oto
`The effect 0! WI pacing on P-wave dispersion in patients with
`dual-chamber pacemakers
`8
`T Palecek. A Linnari, JL‘. Lubanda. S Magage, D Karerova,
`J. BulIas, M Aschermann
`Early diastolic mitral annular velocity and color M-mode flow
`propagation velocity in the evaluation of left ventricular diastolic
`function in patients with Fabry disease
`13
`M. Bonacchi. E Prifil, M. Maian . G l-rati. NS. Nathan.
`M Leaccne
`Mitral valve surgery simultaneous to coronary revascularization in
`patients with end-stage ischemic cardiomyopathy 20
`F Nicolim, G Zoiioli. G Cagnoni, A. Agosnnelh, A Colli. c Fragmm,
`B Borrello C. Beghl, T. Gherli
`Mitrat valve annuloplasty and myocardial revascularization in the
`treatment of ischemic dilated cardiomyopathy 28
`D. Yesilburea, A Serdar. T. Senluik, Z. Serdar S. Sag. J. Gordan
`Effect oi N-acetylcysteine on oxidative stress and ventricular
`function in patients with myocardial infarction 33
`RE Ulusoy. E. erralp, A. Kirilmaz. F. Kilicaslan, N. Ozmen.
`N Kucukarslan. E. Kardesoglu, L. Tutuncu. O lxeskin. BS. Cebecr
`Aortic elastic properties in young pregnant women 38
`
`G. Orhan, N. Yapici, M. Yuksel, M. Sarg n. S Senay. AS. Yale-in.
`Z Aykac. SA Aka
`Effects of N-acetylcysteine on myocardial ischemia—repenusion
`injury in bypass surgery 42
`
`I Basic science
`
`J.-S. Kwon. S.-J Lee, Y VG Kim. J AW. Bae, K.»K. Hwang, M AC. Cho.
`D.—W. Kim
`Ettect of pressure overload and its recovery on the rat carotid
`artery: change of vascular reactivity and remodeling process
`
`43
`
`Case reports
`H. Kooak, S Karapolai, C. Gimdogdu. to Bozkurt. Y Unit]
`Primary cardiac osteosarcoma in a pregnant woman 56
`M. Tanaka. Y Gore, 8. SLMUKI.
`l. Mom. Y. Otsuka, S. Miyalakr
`H. Nonogi
`Postinfarction cardiac rupture despite immediate repertusion
`therapy in a patient with severe aortic valve stenosis
`59
`M, May. Y. Finkbeiner, 8. Gunia. M. Seenaler. J. KnQ'rg. R Hetzer
`Metastasizing testicular germ-cell tumor with infiltration of the
`right heart: indication for primary metastasectomy 63
`
`Graphic report
`N. lkeda. H. Hara, R Naitajima, M. Shiba, M, Wada, T. TSUII.
`R Iljln’la, i. Yoshitama.T Tsunoda, M Nakamura M Suzuki.
`H Hase. K. Sugi
`An example that presented giant aneurysm ot the angina pectoris
`after percutaneous coronary intervention
`66
`
`Erratum ea
`
`indexed in index Medicus, Current Contents, EMBASE
`
`
`
`@ Springgsrl‘filiz'réErma-d
`
`I1
`0 fieart Vessels ISSN 0910-8327 HEVEE 0 21(1) 1-68 (2006)
`Subject USEapryrIg t Laws
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`Vessels
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`Heart Vessels (2006) 21:1–7
`DOI 10.1007/s00380-005-0850-8
`
`ORIGINAL ARTICLE
`
`© Springer-Verlag 2006
`
`Jin Yokoyama · Motoi Kushibiki · Takayuki Fujiwara
`Yujin Tamura · Naotaka Maeda · Takumi Higuma
`Shingo Sasaki · Fuminobu Yoshimachi
`Toshiro Matsunaga · Hiroyuki Hanada · Tomohiro Osanai
`Ken Okumura
`Feasibility and safety of thrombectomy with TVAC aspiration catheter
`system for patients with acute myocardial infarction
`
`Received: August 23, 2004 / Accepted: July 8, 2005
`
`Abstract Early reperfusion with angioplasty and stenting is
`established as a central, effective treatment for acute myo-
`cardial infarction (AMI). The role of thrombectomy prior
`to angioplasty remains to be elucidated. To evaluate its
`feasibility, safety, and efficacy, thrombectomy using a
`TVAC aspiration catheter system was attempted prior to
`angioplasty and stenting in 40 consecutive patients with
`AMI. Fifty consecutive patients with AMI in whom
`angioplasty and stenting were performed without prior
`thrombectomy served as controls. Neither distribution of
`Killip classification nor culprit lesion was different between
`the two groups. In patients treated with the TVAC system,
`the procedure was successful in 39/40 patients (98%) and
`there were no procedure-related complications. In the final
`coronary angiogram, TIMI-3 (Thrombolysis in Myocardial
`Infarction) flow was obtained in 37/40 (93%) in patients
`treated with the TVAC system and 43/50 (86%) in control
`patients. Electrocardiograms before and after coronary in-
`tervention were analyzed in patients with ST elevation AMI
`(35 patients treated with the TVAC system and 41 control
`patients). ST elevation recovery >50% of the initial value
`was observed after coronary intervention in 26/35 (74%) in
`patients treated with the TVAC system and 26/41 (63%) in
`control patients (P = 0.33). In the case of anterior AMI, ST
`elevation recovery >50% of the initial value was observed in
`13/17 (76%) in patients treated with the TVAC system and
`8/20 (40%) in control patients (P = 0.045). Thus, thrombec-
`tomy using a TVAC system is feasible, safe, and may have
`the potential to enhance ST-segment resolution in patients
`with anterior AMI.
`
`Key words Acute myocardial infarction · Primary angio-
`plasty · Thrombectomy · ST resolution
`
`J. Yokoyama (*) · M. Kushibiki · T. Fujiwara · Y. Tamura ·
`N. Maeda · T. Higuma · S. Sasaki · F. Yoshimachi · T. Matsunaga ·
`H. Hanada · T. Osanai · K. Okumura
`Second Department of Internal Medicine, Hirosaki University
`School of Medicine, 5 Zaifu-cho, Hirosaki 036-8562, Japan
`Tel. +81-172-39-5057; Fax +81-172-35-9190
`e-mail: yokoyama@cardiologist.jp
`
`Introduction
`
`Acute myocardial infarction (AMI) is caused by thrombotic
`coronary artery occlusion following plaque rupture in
`most patients.1,2 Primary coronary intervention with balloon
`angioplasty and stenting has been established as a first-line
`therapy for AMI.3–5 During this catheter-based interven-
`tion, however, thrombo- and/or atheroembolization in the
`coronary artery segment distal to the culprit lesion may
`occur, and a consequent slow flow or no-reflow phenom-
`enon may result in adverse clinical outcomes.6–11 Thus, not
`only theoretically but practically, thrombus removal from
`the coronary artery occlusive lesion may be advisable in
`order to reduce the thrombotic burden, and to improve
`coronary flow and procedural results. Recently, a new
`thrombus aspiration catheter system, TVAC (Nipro,
`Osaka, Japan) has been designed to remove thrombo-
`occlusive tissue from the coronary artery and saphenous
`vein graft. The present report evaluates the feasibility,
`safety, and efficacy of this TVAC catheter system as a pri-
`mary catheter-based intervention for AMI.
`
`Materials and methods
`
`Aspiration system
`
`The TVAC aspiration catheter system consists of a very
`flexible, 4.5-F catheter that can be advanced over a 0.014-
`inch guidewire through a 7-F guiding catheter using a
`monorail system, an extension tube, a vacuum pump, and
`a collection bottle. The catheter has a unique oblique tip
`shaped like the beak of duck’s bill that provides a wide
`opening area and large lumen for aspiration as compared
`with the RESCUE PT catheter (Boston Scientific, Maple
`Grove, MN, USA) and the Export aspiration catheter
`(PercuSurge System, Medtronic AVE, Danvers, MA, USA)
`(Fig. 1). A marker is embedded at the distal end of the
`catheter so that its position can be identified under fluoros-
`copy. While the tip of the TVAC catheter is advanced and
`
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`2
`
`A
`
`B
`
`C
`
`Fig. 1A–C. The TVAC system consists of a 4.5-F aspiration catheter (A), with the distal shaft shaped like the bill of a duck (B) and a vacuum
`pump (0.9 atm) with a connection bottle (C)
`
`pulled back through the thrombus, continuous suction with
`a negative pressure at 0.9 atm is applied. Approximately 20–
`40 ml of arterial blood can be withdrawn during one attempt
`at thrombus removal.
`
`Patients
`
`The study included those patients with AMI who presented
`symptoms within 24 h before admission, with a total or sub-
`total occlusive lesion in the infarct-related coronary artery,
`with the lumen diameter of the coronary artery segment
`proximal to the occlusion site being >2 mm, and without a
`significant stenotic lesion in the main trunk of the left coro-
`nary artery. Those patients manifesting cardiogenic shock
`and with contraindications for coronary intervention were
`excluded. Thrombectomy with the TVAC system was initi-
`ated in May 2003, and was attempted in 40 consecutive
`patients with AMI, before balloon angioplasty and stenting,
`for a period of 8 months. Another group of 50 consecutive
`patients with AMI in whom angioplasty and stenting was
`performed without prior thrombectomy served as controls.
`These control AMI patients had been admitted to our hos-
`pital before the initialtion of the use of a thrombectomy
`device, including the TVAC system. In all patients, AMI
`was diagnosed by severe chest pain lasting >30 min, persis-
`tent ST segment elevation or depression on ECG, and ab-
`normal rises of biochemical markers such as troponin T and
`the MB fraction of creatine kinase. Cardiac catheterization
`procedures including aspiration of intracoronary thrombus
`and primary coronary angioplasty were explained to all
`patients, and informed consent was obtained before the
`procedures. In all patients, aspirin (200 mg) was orally ad-
`
`ministered just after admission to the emergency room,
`and 10 000IU heparin was administered intravenously at
`the beginning of the catheterization procedure. Activated
`coagultion time was maintained at >240 s throughout the
`procedure by administering additional 1000-IU doses of
`heparin at an appropriate interval. None of the patients was
`pretreated with a thrombolytic agent and a glycoprotein
`IIb/IIIa inhibitor, since the latter agent was not available in
`Japan. Nicorandil was administered prior to primary percu-
`taneous coronary intervention (PCI) in none of the patients
`in the TVAC group and in 31 patients in the control group.
`Angiotensin-converting enzyme inhibitor or angiotensin II
`receptor blocker were administered to all patients. Statin
`and b-adrenergic receptor blocker were administered to 29
`and 34 patients, respectively, in the group treated with the
`TVAC system, and 15 and 35 patients, respectively, in the
`control group.
`
`Cardiac catheterization and coronary intervention
`
`In both groups of patients, after intracoronary adminis-
`tration of isosorbide dinitrate (2mg), using 4-F Judkins
`catheters, the arteriograms of the infarct- and non-
`infarct-related arteries were taken from multiple projec-
`tions. The 7-F guiding catheter was engaged to the orifice
`of the infarct-related coronary artery, and a 0.014-inch
`guidewire was advanced to the periphery of the infarct-
`related artery while penetrating the occluded lesion. In con-
`trol AMI patients, conventional PCI (ballooning and
`stenting with either an NIR stent (Boston Scientific, Maple
`Grove, MN, USA), a S670/660 stent (Medtronic AVE,
`Danvers, MA, USA) or a BX Velocity stent (Cordis,
`
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`

`Miami, FL, USA) was performed. In patients treated with
`the TVAC system, while applying continuous aspiration the
`TVAC aspiration catheter was inserted into the infarct-
`related artery along the guidewire, and advanced until the
`tip of the catheter reached the occlusion site before balloon-
`ing and stenting. The aspiration catheter was further
`advanced to the segment distal to the occlusion site when
`this could be performed without any excessive pressure.
`The aspiration catheter was pulled back while aspirating the
`blood, and removed from the guiding catheter. The blood in
`the guiding catheter was removed for the case in which a
`thrombus was left in the lumen of the guiding catheter. The
`lumen of the aspiration catheter was washed with heparin-
`ized saline, and the same procedure was repeated until an
`angiographically defective shadow(s) suggesting the pres-
`ence of intralumen thrombus disappeared in the infarct-
`related artery, or the volume of the arterial blood aspirated
`to the collection bottle reached 80ml. Then, a conventional
`balloon angioplasty and stenting with either a multilink
`Penta stent (Guidant Vascular Intervention Group,
`Lakeside Drive, Santa Clara, CA, USA) or a S670 stent
`were performed when significant stenosis >75% of the
`lumen diameter was present at the lesion.
`
`Evaluation of the effect of thrombectomy
`
`Angiographic analysis was performed by two independent
`investigators to evaluate the procedural results and the oc-
`currence of distal embolization for each patient. The coro-
`nary flow grade in the infarct-related artery was determined
`before and after coronary intervention using a Thromboly-
`sis in Myocardial Infarction (TIMI) flow grade classifica-
`tion.12 In the patients with ST elevation AMI (35 patients
`treated with the TVAC system and 41 control patients), 12-
`lead ECGs before and after coronary intervention were
`analyzed and a sum of the degree of ST elevation in the
`three ECG leads showing manifest ST elevation was mea-
`sured. Persistent ST elevation >50% of the degree of ST
`elevation observed before the intervention was considered
`to represent impaired reperfusion.13,14
`
`3
`
`Follow-up
`
`Aspirin (200mg daily), ticlopidine (200mg daily for 4
`weeks), and angiotensin-converting enzyme inhibitor or
`angiotensin II receptor blocker were administered to all
`patients. Statin and b-adrenergic receptor blocker were ad-
`ministered to 29 and 34 patients, respectively, in the group
`treated with the TVAC system, and to 15 and 35 patients,
`respectively, in control group. In-hospital outcomes and
`those within 3 months after discharge were evaluated in all
`patients.
`
`Statistical analysis
`
`All data are shown as mean ± 1 standard deviation. Differ-
`ence in categorized data was analyzed using the Fisher exact
`probability test. P < 0.05 was considered to the significant.
`
`Results
`
`Effect of thrombectomy using the TVAC system
`
`Clinical characteristics of the study patients are summarized
`in Tables 1, 2, and 4. In the patients treated with the TVAC
`system, the procedure of thrombectomy was successful in
`39/40 patients (98%). In one patient, the TVAC system
`delivery was unsuccessful because of the vessel tortuosity.
`Of the 39 patients with successful delivery of the system,
`TIMI-3 flow was obtained in 29 patients and TIMI-1 or -2
`flow in 10 after thrombectomy. TIMI flow grade at each
`stage of the procedures is shown in Fig. 2. There was no
`procedure-related complication. Representative cases of
`successful TVAC thrombecomy are shown in Fig. 3. After
`the procedure of coronary intervention, no patient required
`target vessel revascularization during their stay in hospital.
`Also, there was no death and stroke in any of the patients.
`In the 3 months following coronary intervention there was
`also no death, no subacute thrombosis, and no stroke in any
`
`Table 1. Clinical baseline characteristics of the two groups of patients
`TVAC (n = 40)
`Control (n = 50)
`
`Age (years)
`Male
`Hypertension
`Hyperlipidemia
`Diabetes mellitus
`Current smoker
`Culprit lesion
`Left anterior descending artery
`Left circumflex artery
`Right coronary artery
`Severity of CAD
`Single-vessel disease
`Double-vessel disease
`Triple-vessel disease
`
`CAD, coronary artery disease
`
`64 ± 10
`34 (84%)
`20 (50%)
`19 (48%)
`15 (38%)
`27 (67%)
`
`18 (45%)
`6 (15%)
`16 (40%)
`
`18 (45%)
`10 (25%)
`12 (30%)
`
`63 ± 12
`38 (76%)
`24 (48%)
`21 (42%)
`20 (40%)
`35 (70%)
`
`23 (46%)
`8 (16%)
`19 (38%)
`
`27 (54%)
`17 (34%)
`6 (12%)
`
`P
`
`0.756
`0.604
`>0.999
`0.672
`0.831
`0.822
`
`>0.999
`>0.999
`>0.999
`
`0.525
`0.488
`0.061
`
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`

`4
`
`Table 2. Severity of myocardial infarction of in the two groups of patients
`TVAC (n = 40)
`Control (n = 50)
`
`Killip classification
`1
`2
`3
`4
`Initial TIMI grade
`0
`1
`2
`3
`Time to recanalization (min)
`Max CPK (IU/l)
`LVEF (acute phase) (%)
`IABP utilization
`
`38 (95%)
`1 (3%)
`1 (3%)
`0 (0%)
`
`29 (73%)
`1 (3%)
`6 (15%)
`4 (10%)
`307 ± 228
`2706 ± 1804
`50.4 ± 7.6
`8 (20%)
`
`43 (86%)
`7 (14%)
`0 (0%)
`0 (0%)
`
`30 (60%)
`6 (12%)
`12 (24%)
`2 (4%)
`359 ± 294
`3242 ± 2242
`51.2 ± 7.7
`10 (20%)
`
`P
`
`0.502
`0.289
`0.444
`>0.999
`
`0.267
`0.127
`0.427
`0.401
`0.478
`0.254
`0.199
`>0.999
`
`TIMI, thrombolysis in myocardial infarction; LVEF, left ventricular ejection fraction; IABP,
`intra-aortic balloon pumping; CPK, creatine phosphokinase
`
`41) (P = 0.241) (Table 3). ST elevation recovery >50% of
`the initial degree of ST elevation was observed after coro-
`nary intervention in 26/35 (74%) patients treated with the
`TVAC system and in 26/41 (63%) control patients (P =
`0.33). In the cases of anterior AMI, resolution of ST eleva-
`tion was 60% ± 26% in patients treated with the TVAC
`system (n = 17) and 40% ± 24% in control patients (n = 20)
`(P = 0.017). ST elevation recovery >50% of the initial de-
`gree of ST elevation was observed after coronary interven-
`tion in 13/17 (76%) patients treated with the TVAC system
`and in 8/20 (40%) control patients (P = 0.045) (Table 5).
`
`Discussion
`
`Fig. 2. Changes in Thrombolysis in Myocardial Infarction (TIMI) flow
`grade in the two groups of patients
`
`Feasibility and safety of thrombectomy with
`the TVAC system in AMI
`
`patients. Of the 39 patients in whom thrombectomy was
`successfully performed, no visible thrombus or plaque seg-
`ment was detected in 27 patients, while in the other 12
`patients red thrombus was detected in 9, white thrombus
`in 3, plaque segment containing macrophages in 5, and
`cholesterine crystals in 4.
`
`Comparison of the results of coronary intervention with
`and without prior TVAC system
`
`In the final coronary angiogram after coronary intervention,
`TIMI-3 flow was obtained in 37/40 (93%) patients treated
`with the TVAC system and in 43/50 (86%) control patients
`(P = 0.502) (Table 3). Electrocardiograms before and after
`coronary intervention were analyzed in patients with ST
`elevation AMI. Resolution of ST elevation after interven-
`tion was 62% ± 24% of the baseline value of ST elevation in
`patients treated with the TVAC system (n = 35) and 53% ±
`34% in control patients treated with conventional PCI (n =
`
`Clinical evidence obtained from previous coronary an-
`gioplasty trials showed that the presence of angiographic
`thrombus is associated with increased incidences of abrupt
`closure and early and late post-procedure occlusion of the
`infarct-related artery.7,10 Although new treatments for acute
`coronary syndrome and high-risk angioplasty have been
`under development, a new device that can easily, rapidly,
`and safely remove occlusive tissue, thrombus, and friable
`materials from the coronary arteries remains necessary.
`With the use of a TVAC system, a new thrombectomy
`catheter system developed in Japan, in patients with AMI,
`we demonstrated that the thrombectomy system improved
`coronary flow in the infarct-related artery, assessed by
`TIMI flow grade. TIMI-3 flow was obtained in 29/40 (75%)
`patients treated with the TVAC system immediately after
`thrombectomy (Fig. 2). There were no procedure-related
`complications. After thrombectomy, a standard angioplasty
`including stent implantation was successfully accomplished
`in all patients. Further, there was no death, no stroke, and
`no revascularization therapy required while the patients
`were in hospital. In the 3 months following coronary inter-
`
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`5
`
`B
`
`Fig. 3. A Thrombotic occlusion
`in the middle of the left anterior
`descending coronary artery
`(indicated by an arrow). B
`Initial recanalization with the
`TVAC system. An arrow
`indicates the occlusion site
`before treatment. C Final left
`coronary angiogram after
`treatment with the TVAC
`system. An arrow indicates the
`occlusion site before treatment
`
`A
`
`C
`
`Table 3. Clinical outcomes of the two groups of patients
`TVAC (n = 40)
`
`Control (n = 50)
`
`P
`
`Clinical success
`Rate of TIMI-3 at the final angiogram
`ST resolution from the initial value
`Rate of recovery of ST elevation >50%
`of the initial value
`
`40 (100%)
`93%
`62% ± 24%
`74%
`
`50 (100%)
`86%
`53% ± 34%
`63%
`
`>0.999
`0.502
`0.241
`0.33
`
`Clinical success: successful angioplasty without cardiac death, reinfarction, emergency bypass
`surgery, and stroke in hospital
`
`vention there was also no death, no subacute thrombosis,
`and no stroke in any of the patients. Thus, thrombectomy
`with the present TVAC system was found to be feasible and
`safe.
`The TVAC system used in this study is a specially de-
`signed monorail catheter which is as flexible as a balloon
`catheter and can be advanced distally to the lesion with
`thrombus. Furthermore, the unique oblique tip with a shape
`like the beak of duck’s bill allows a passage through a
`stenotic lesion and increases trackability in tortuous tra-
`jectories. Compared with other aspiration catheters, the
`TVAC has a wide opening area (5.59mm2 in TVAC vs
`
`1.37 mm2 in RESCUE PT and 3.90mm2 in Export) and large
`lumen (0.90 mm2 in TVAC vs 0.60mm2 in RESCUE PT and
`0.82 mm2 in Export) for aspiration. The system is simple,
`and extensive experience or a long learning period is not
`necessary, as may be the case with the other aspiration
`catheters.15,16
`
`Efficacy of thrombectomy with the TVAC system in AMI
`
`This study showed that, in the final arteriogram of the inf-
`arct-related artery, TIMI-3 grade flow was obtained in 37/40
`
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`6
`
`Table 4. Clinical baseline of the two groups of patients (anterior AMI)
`TVAC (n = 18)
`Control (n = 23)
`
`Age (years)
`Male
`Hypertension
`Hyperlipidemia
`Diabetes mellitus
`Current smoker
`Severity of CAD
`Single-vessel disease
`Double-vessel disease
`Triple-vessel disease
`Killip classfication
`1
`2
`3
`4
`Initial TIMI grade
`0
`1
`2
`3
`Time to recanalization (min)
`Max CPK (IU/l)
`LVEF (acute phase) (%)
`IABP utilization
`
`62 ± 11
`13 (72%)
`9 (50%)
`10 (56%)
`7 (39%)
`11 (61%)
`
`8 (44%)
`5 (28%)
`5 (28%)
`
`18 (100%)
`0 (0%)
`0 (0%)
`0 (0%)
`
`12 (67%)
`1 (6%)
`4 (22%)
`1 (6%)
`297 ± 209
`3351 ± 2241
`48.0 ± 10.3
`6 (33%)
`
`60 ± 13
`17 (74%)
`13 (57%)
`11 (48%)
`8 (35%)
`15 (65%)
`
`17 (74%)
`5 (22%)
`1 (4%)
`
`20 (87%)
`3 (13%)
`0 (0%)
`0 (0%)
`
`13 (57%)
`4 (17%)
`6 (26%)
`0 (0%)
`451 ± 341
`3007 ± 2213
`47.1 ± 8.7
`7 (30%)
`
`P
`
`0.689
`>0.999
`0.758
`0.756
`>0.999
`>0.999
`
`0.106
`0.725
`0.07
`
`0.243
`0.243
`>0.999
`>0.999
`
`0.54
`0.363
`>0.999
`0.439
`0.11
`0.626
`0.805
`>0.999
`
`Table 5. Clinical outcomes in patients with anterior AMI
`TVAC (n = 17)
`
`Control (n = 20)
`
`P
`
`Rate of TIMI-3 at the final angiogram
`ST resolution from the initial value
`Rate of recovery of ST elevation >50%
`of the initial value
`
`83%
`60% ± 26%
`76%
`
`87%
`40% ± 24%
`40%
`
`0.502
`0.017
`0.045
`
`(93%) patients treated with the TVAC system followed by
`angioplasty and stenting, compared with 43/50 (86%) in
`control patients treated with angioplasty and stenting with-
`out prior thrombectomy. Although not significant, primary
`angioplasty with prior thrombectomy with the TVAC sys-
`tem was found to be of use in the treatment of AMI. It
`should be pointed out that this study was not done in
`a prospective, randomized fashion. Thus, thrombectomy
`using the TVAC system was attempted in 40 consecutive
`AMI patients. Another group of 50 consecutive patients
`with AMI in whom angioplasty and stenting were per-
`formed without prior thrombectomy served as a control
`group, since at that time no thrombectomy device was avail-
`able. There was no difference in the clinical characteristics
`between the two groups, including the distribution of the
`infarct-related artery and the degree of coronary flow
`before coronary intervention.
`Although epicardial coronary flow has been identified as
`an important predictor for clinical outcomes, it is well
`known that patency of the epicardial vessel does not neces-
`sarily indicate adequate reperfusion at the level of coronary
`microcirculation.17 Impairment of microvascular function
`may occur particularly during mechanical reperfusion pro-
`cedures. Thus, primary angioplasty for AMI may induce
`
`dislodgment of thrombi, causing distal macroembolization
`and microembolization. Further, mechanical dilation re-
`sults in plaque disruption and may induce distal emboliza-
`tion with atheromatous gruel and plaque components.18
`Distal embolization and subsequent slow flow or no-reflow
`have been reported to occur in up to 30% of patients
`treated with primary angioplasty.19–22
`An analysis of ST-segment resolution has been validated
`as a surrogate marker for restoration of microvascular
`functiohn. In patients with ST elevation AMI, early re-
`solution of ST elevation >50% of the initial degree of ST
`elevation has been shown to be associated with greater
`myocardial salvage and improved clinical outcome.13,14,23 In
`the present study, the degree of resolution of ST elevation
`after primary coronary intervention and the number of pa-
`tients with ST elevation recovery more than 50% of the
`initial degree of ST elevation after primary coronary inter-
`vention were both greater in the patient group treated with
`the TVAC system than in the group without prior throm-
`bectomy, although the difference did not reach statistical
`significance. When the same analysis was made in the pa-
`tients with anterior AMI, both parameters were signifi-
`cantly greater in the group treated with the TVAC system
`than in the group without prior thrombectomy. Thus,
`
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`though not done in a prospective, randomized fashion, this
`study suggested that thrombectomy with the TVAC system
`prior to primary coronary intervention may enhance ST-
`segment resolution in the infarct-related artery in patients
`with AMI. It may be pointed out that the TVAC system was
`more effective in patients with anterior AMI that in those
`with nonanterior AMI. In fact, in nonanterior AMI the
`results of ST resolution were similar between the patient
`groups with and without treatment with the TVAC system.
`The present study could not clarify the reason for the differ-
`ence in the effect between anterior and nonanterior AMI.
`Anterior AMI may be at a higher risk of microvascular
`dysfunction than nonanterior AMI because of the differ-
`ences in the number of side branches and the size of the
`perfusion territory. Further studies in this respect are
`required.
`
`Study limitations
`
`This study was not done in a prospective, randomized fash-
`ion, and a comparison of the clinical outcomes between the
`patient groups treated with and without prior thrombec-
`tomy may be inappropriate in reaching some conclusions.
`Further prospective studies are necessary to establish the
`effectiveness of the TVAC thrombectomy system. Also,
`the present study did not show the long-term effect of
`the TVAC system. Since the prognosis of the patients
`with AMI is influenced by many factors including the
`size of infarction, left ventricular function, ventricular
`arrhythmias, and residual myocardial ischemia, the long-
`term effect of the TVAC system on the prognosis should be
`evaluated cautiously.
`
`Conclusions
`
`Thrombectomy with the TVAC system before balloon
`angioplasty and stent implantation in patients with AMI is
`feasible and safe, and may have the potential to mini