Improved Myocardial Fatty Acid Utilization after Percutaneous

Improved Myocardial Fatty Acid Utilization after Percutaneous Transluminal Coronary Angioplasty Ichiro Matsunari, Takashi Saga, Junichi Taki, Yoshihiro Akashi, Jun-ichi Hirai, Takanobu Wakasugi,

Takahiko Aoyama, Munetaka Matoba, Kenji Ichiyanagi and Kinichi Hisada Departments ofRadiolo@' and Internal Medicine, Fukui Prefectural Hospital, FuIa4 Japan; and Department of Nuclear

Medicine, Kanazawa University, School ofMedicine, Kanazawa, Japan CASE REPORT Exerdse-reinjection @°ii imaging and resting 20-mm and 3-hr BMIPP imagingwere performed before and 4 mo after percuta

neous transluminal coronary angioplasty (PTCA)in a patient with effort angina Before PTCA, exercise 2o1@flimaging showed decreased 201@fl activity in the septal wall, with significantfill-in on

A 68-yr-oldmansufferingfromeffortanginawas admittedto our hospital, and exercise reinjection 201'flimaging and resting

BMIPPimagingwereperformedbeforeand4 moafterPTCA.The patientdid not havea historyof previousmyocardialinfarction andhadno ongoinganginaat the timeof follow-up.

the reinjection201@fl image. The resting20-mmBMIPPimage Coronary Anglography showed decreased activityin the septal wall,witha slightredis The patient underwentcoronaiy angiography,which revealed tnbutionon the 3-hr BMIPPimage. The @°@TI and BMIPPimages 90% stenosis in the luminal diameter of the left anterior descend 4 mo after PTCA showed significant improvement in the 201@fl ing artery. Percutaneous coronary angioplasty was performed patternand BMIPPuptake in the septai wall with no abnormally successfully, showing less than 25% of stenosis in the luminal decreased activities. diameter (Fig. 1). Key Words: iodine-123 BMIPP;ischemic heart disease; percu

taneous transluminaicoronaryangioplasty;myocardiaifattyacid J NucIMed1995;36:1605-1607

BMIPPand Thallium Studies BMIPPimagingwas performedwith an injectionof 111—148 MBqBMIPPduringrestfollowedby a 20-misalineflushthrough an intravenous cannula inserted before the start of the study.

SPECT images were acquired 20 mm and 3 hr after injection (resting20-mmBMIPPand 3-hrBMIPP)usinga three-headed SPECF camerawith high-resolution,parallel-holecollimators.A totalof 60 projectionimageswereobtainedover360° in 6° incre ments,with30sec perview.Thedatawererecordedin 128x 128

etabolic conditions in ischemic but viable myocar dium can recover after revascularization therapy. Tamaki et al. demonstrated a decrease in [‘8F]-deoxyglucose

matrices into the magnetic disc. The energy discrimination

(FDG) uptake aftercoronaiy arterybypass graftingin isch

centered on 159keV with a 20%window. To reconstructtransax

emic but viable myocardium (1). Although fatty acid is the main cardiac energy source during resting conditions, little

ial tomographicimages from the acquisitiondata, Butterworth

was

and ramp filters were used. The parameterof the Butterworth

filterwasorder8, andthecutofffrequencywas 0.15cycles/pixel.

is known about fatty acid utilization before and after re Within a week of the BMIPP study, exercise stress 20―fl vascularization.Recently, ‘@I-labeled 15-(p-iodophenyl)3R, SPECTimagingwas performedusinga supinebicycleergometer. S-methylpentadecanoic acid (BMIPP) has been proposed Exercise was startedwith a workloadof 25 W andincreasedby 25 as a potential fatty acid probe for myocardial fatty acid W intervalsfor every 2 mmof stress. Exercisewas terminated utilization (2—4).In patients with ischemic heart disease, when either severe chest pain, serious arrhythmia,ST depression decreased myocardial BMIPP uptake compared with @°‘11 in of more than 0.2 mV and/orfatigueoccurred. One minute before cessationof exercise,74MBq201'flwereinjectedandanexercise the ischemic zone area was reported (5). We hypothesized image was obtained under the same acquisition conditions and that fatty acid utilization would recover after successful reconstruction method used for the BMIPP SPECT study, with percutaneous transluminal coronary angioplasty (PTCA). the exception that energy discriminationwas centered on 70 keV

We present a case of ischemic heart disease, which dem

with a 20%window. An additional37 MBq 20―fl were injected at

onstrates significant improvement in BMIPP uptake in the ischemic zone after PTCA.

reinjection imaging was started within 10 mm of the second

rest 3—4 hr after the first injectionduringexercise, and 2o'@fl injection. SPECT

ReceivedApril25, 1994;revisionacceptedAug.1, 1994. Forcorrespondenceor repdntscont@: Ithro Matsunail,MD,Nuklearmediz inische KlinIcund Pdiklin@ DerTechnischen UnversitátMUnchen, KJk*um rechts

der sw, smaningerSIr.22, 81675MOnchen,Germany.

MyocardialFattyAcid Imagingafter PTCA• Matsunailat al.

BeforePTCA, exercise201'flimagingshowed decreased 20―fl activity in the septal wall, with significant fillin on the 20―flrein jection image. On the other hand, the resting 20-mm BMIPP image

1605

Exercise

Stress TI

Re-injection

i)

Pre-PTCA 20mm

4

3hr

RestingBMIPP

FIGURE2. Transaxialslices of exercise(upperleft), @°@11 rein jection (upper right), 20-mm (lower left) and 3-hr BMIPP (lower nght)

imaging3 wkbeforePCTADecreasedactivityinthe septalwallwas observed on the exercise @°@fl image with significant fillin on the 20111remnjectionimage, indicating exercise-induced ischema Sig nfficantly decreased BMIPP adllvfty was noted on both the 20-mm and 3-hr BMIPP images.

grafting using PET and FDG (1). Terada et al. reportel a case of acute coronaiy syndrome with a slight improve Post-PTCA ment in BMIPP uptake 16 days after PTCA (6). Apparent decreased BMIPP uptake was still observed in the post ischemic myocardium, however, even though PTCA was successfully performed. The incomplete recoveiy of de creased BMIPPuptake in theirobservation mightbe due to the short interval of 16 days between PTCA and BMIPP FiGURE1. Coronaryangiographybeforeand afterpercutane imaging. In contrast, the intervalfor our patientwas 4 mo, which should be sufficient for myocardial metabolic alter ous transluminal coronary angioplasty (PTCA).The pre-PTcA an giogram(upper)revealedsignificantstenosis inthe leftascending ation after vascular intervention. Tamaki et al. noted that descending artery, wh@himproved to less than 25% of stenosis in the discordance between BMIPP and @°‘Tl uptake fre the luminaldiameterafterPTCA(lower). quently occurs before 4 wk after the onset of myocardial infarction. In contrast, the frequency of discordance be showed apparent decreased activity in the septal wall, with a tween the two tracerswas not high after 4 wk (7), suggest ing that the recovety of fatty acid metabolism might be a slight redistribution on the 3-hr BMIPP image (Fig. 2). As illustrated in Figure 3, @°‘Tl and BMIPP imaging 4 mo after time-dependent phenomenon. In addition, the experimen PTCA showed significant improvement in @°‘Tl pattern and

A

BMIPP uptake in the septal wall, with no apparent abnormally

decreased activitieswith both @°@Tl and BMJ.PP.When ROIs of

Exercise

5 x 5 pixelswere placedon the centerof the septalandlateral

Re-injection

wallsfor normalreferenceregionson the transaxialsliceson the 20-mm BMIPP images, the septal-to-lateral

ratio before PTCA

was 0.53,whichincreasedto 0.90aftercoronaiyarteiyinterven tion.

StressTI

‘ 1)

DISCUSSION

@

@

We found decreased myocardial BMIPP uptake in the area of stress-induced ischemia on @°‘Tl imaging,which is consistent with our previous reportthat impairedfatty acid utilization in ischemic myocardium already exist during rest (5). In addition to these observations, decreased BMIPP uptake recovered significantly4 mo after revascu larization therapy, indicating that impaired fatty acid utili zation is reversible. This is concordant with glucose me tabolism normalization after coronaiy arteiy bypass

1606

20mm

3hr

RestingBMIPP , FIGURE3. TransaxialsI@esof exercise(upperleft),reunjection 20111(upper right), 20-mm Qower left) and 3-hr BMIPP (lower nght) imaging 4 mo after PCTA A significant improvement of radloactivi

ties was notedon both @°@11 BMIPPimaging.

The Journalof NudearMedicine• Vol.36 • No. 9 • September1995

tal study using PET and FDG showed sustained metabolic derangement after transient ischemia (8). Thus, sufficient time after PTCA may be one of the important factors to influence the recoveiy in BMIPP uptake in the salvaged area by PTCA. Persistent increased FDG uptake several months

2. KnappFF Jr,AmbroseKR, GoodmanMM.New radioiodinated methyl branchedfatty acidsfor cardiacstudies.EurlNuclMed 1986;12:S39-S44. 3. DudczakR, SchmolinerR, AngelbergerP, KnappFF, GoodmanMM. Structural'ymodifiedfattyacids:clinicalpotentialas tracersof metabolism. Eurl NucI Med 1986;12:S45—S48.

after successfully performed revascularization was still ob

4. YonekuraY, BrillAB, SomP, et at. Regionalmyocardialsubstrateuptake inhypertensiverats:a quantitativeautoradiographic measurement.Science

served, however, by Marwick et al. (9), indicating that myo cardial glucose metabolism remains abnormal in a consider able portion of salvaged myocardium. Further investigation

5. MatsunariI, Saga T, Taki J, et at. Kinetics of iodine-123-BMIPPin patientswith prior myocardialinfarction:assessment with dynamic, rest andstress imagescomparedwith stress @°‘TI SPECT.I Nucl Med

with a number of subjects is needed to clarify the role of myocardial fatty acid metabolism after revascularization. CONCLUSION

Our patient had significant improvement in myocardial fatty acid utilization after PTCA, suggesting that serial analysis of BMIPP imagingmight provide insights into the understandingof tissue metabolic alternationsafter revas cularization. REFERENCES 1. TamakiN, YonekuraY, YamashitaK, et at.Positronemissiontomography using fluorine-18 deoxyglucose in evaluation of coronary artery bypass

grafting.Am J Cardiol 1989;64:860-865.

I

1985;227:1494—1496.

1994;35:1279—1285.

6. TeradaK, SugiharaH, TaniguchiY, et at. A case of acute coronary syndrome followed by @°“fl, @I-BMIPPand ‘231-MIBG myo cardial imagings before and after PTCA. Jpn I Nucl Med 1993; 30:1459—1463. 7. Tamaki N, Kawamoto M, Yonekura Y, et at. Regional metabolic abnormality in relation to perfusion and wall motion in patients

with myocardial infarction:assessment with emission tomography using an iodinated branchedfatty acid analog. I Nuci Med 1992; 33:659—667. 8. Schwaiger M, Schelbert HR. Ellison D, et al. Sustained regional abnormal ities in cardiac metabolism after transient ischemia in chronic dog model. I

Am CoilCardiol1985;6:336-347. 9. MarwickTH, MaclntyreWJ,LafontA, NemecJJ,SalcedoEE. Metabolic responsesof hibernatingand infarctedmyocardiumto revascularization:a follow-upstudyofregional perfusion,functionand metabolism.Ci,vulation 1992;85:1347—1353.

Scatter

(Continuedfrom page 3A) our mind. Innocent, without bias, fresh. Rather a charming substitute for ignorance: the lack ofknowledge, the guilt ofhaving ignored or neglected

an area. Did this stammer over the choice ofword reflect the arroganceof the successful, a disorder affecting the powerftil in institutional medicine, a dyslexia ofsorts that does not permit the confession of―ignorance?― Or did

it truly reflect innocence, a willingness to learn, to begin anew, to sail unchartedwaters, to recognize the achievement ofothers and to grow? And what ofthose areas about which I am uninformed? I hope that I will only be innocent.

Stanley J. Goldsmith,

MD

Editor-in-Chief TheJournal ofNuclear Medicine September 1995

MyocardialFattyAcidImagingafter PTCA• Matsunatiat al.

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