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Comparison of monoplane and biplane assessment of regional left ventricular wall motion after thrombolytic therapy for acute myocardial infarction
Comparisonof Monoplaneand BiplaneAssessment of Regionalleft Ventricularwall Mot&n After ThrombolyticTherapyfor Acute MyocardialInfarction DAVID R. HOLMES, Jr., MD, ALFRED A. BOVE, MD, RICK A. NISHIMURA, MD, DALE G. GEHRING, BS, JAMES H. CHESEBRO, MD, ROBERT M. OWEN, BA, and HUGH C. SMITH, MD
Regional left ventricular (LV) function was assessed using serial biplane orthogonal LV angiograms recorded before and after repetfusion therapy for acute myocardial infarction (AMI) in 24 patients. Improvement in regional LV function was seen in only 5 patients after reperfu&n therapy when only the right anterior oblique view was analyzed; improvement in regional wall motion was seen in 14 when biplane views were analyzed. Biplane analysis was particularly important in the 12 patients with right coronary artery occlusion, amoq whom the
A
lthough improved mortality and morbidity rates have been documented with reperfusion therapy during acute myocardial infarction (AMI), quantification of myocardial salvage is difficult.1-8 Because the hallmarks of coronary artery disease are regional ischemia and localized contraction abnormalities, reliance on global left ventricular (LV) function may be insufficient. Also, reliance on only 1 angle of view for left ventriculography may underestimate the effects of reperfusion on LV function. We assessed LV function before and after reperfusion for AM1 using serial biplane orthogonal LV angiograms, and evaluated the independent contributions of right anterior oblique and left anterior oblique views for assessing changes in regional LV function. From the Division of Cardiovascular Diseases and Internal Medicine, the Department of Physiology and Biophysics, and the Section of Information Processing and Systems, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Manuscript received August 4, 1986; revised manuscript received November 24,1986, accepted November 25.1986. Address for reprints: David R. Holmes, Jr., MD, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
ri9ht anterior oblique view showed improvement in only 1 patient but the left anterior oblique view showed improverr?ent In 6 patients (p <0.05). Biplane analysis is more sensitive than monoplane right ante&r oblique analysis alone for detecting improvement in LV function after repetfusion therapy for AM. However, both views are complementary, adding information about regional function not revealed by either view alone. (Am J Cardiol 1967;59:793-797)
Methods Patients: The population consisted of 24 patients (20 men, 4 women) sequentially enrolled in the Multicenter Thrombolysis in Myocardial Infarction Trial, which evaluated the relative efficacy of tissue plasminogen activator and streptokinase during AMI.g In all patients baseline LV and coronary angiograms were recorded immediately before administration of the thrombolytic agent and 10 days after attempted reperfusion. The specific projection angles for coronary and LV angiograms recorded at the initial study were reproduced at the lo-day study. Left ventricular angiography and function: Biplane %-mm tine left ventriculograms, 30” right anterior oblique and 60’ left anterior oblique views, were recorded at a rate of 30 frames/s; biplane video recordings using progressive scanning were obtained simultaneously.1° Hemiaxial views were not used. AngiovisP (45 ml) was injected (13 to 15 ml/s) with a multiple sidehole catheter placed retrogradely into the left ventricle. The second or third beat after contrast injection was analyzed; no post-ventricular premature beats were used. Representative end-systolic and end-diastolic video frames at baseline and follow-up studies were de-
794
ASSESSMENT
OF REGIONAL
WALL
MOTION
fined in both the 30° right anterior oblique and 60’ left anterior oblique views as the smallest and largest LV volumes. These video frames were displayed for image analysis in a computer image-processing system (General Electric DF.3009 and IPDC). The apex and the midportion of the aortic valve were identified in each view at end systole and end diastole, thus defining the long axis of the left ventricle? The endocardial surface was then scanned with a computer-generated trackball video cursor to create an outline of the LV cavity. This method allows visual confirmation that the traced outline coincides with the ventricular silhouette. The generated coordinates are transferred in real time to the computer and stored on a magnetic disk. After tracing the long axis and endocardial outline, the X-Y coordinate pairs are used to determine 50 diameters perpendicular to the long axis in the right and left anterior oblique views (Fig. 1). Simpson’s rule was used to calculate ventricular volume and biplane ejection fraction.11 For regional analysis, the biplane images of the left ventricle were separated into 9 regions, as defined by the Coronary Artery Surgery Study.12 Segments 1 through 5 are represented in the right anterior oblique view and segments 6 through 9 in the left anterior oblique view [Fig. 1). The hemisegment percent shortening was defined as [(end-diastolic length - endsystolic length)/end-diastolic length]. Mean shortening for a region was calculated as the average shortening of all hemisegments in that region. Fourteen normal patients evaluated for chest pain of uncertain origin who had normal coronary arteries served as control subjects. Average hemisegment shortening for each segment was defined as average hemisegment shortening in the control subjects minus hemisegment shortening in the patients divided by the normal standard deviation for that specific segment.”
Improvement was defined as ati increase in avetage hemisegment shortening of 0.5 standard deviation or more from normal in the regional LV segment before and 10 days after reperfusion.. Previous studies evaluated the relation of the arterial segment, electrocardiographic documentation of AM1 location and ‘regional wall motion abnormalities.13-16 We related arterial blood supply and the regional wall segment to correlate changes with the occluded artery. With the scheme selected, the right coronary artery is represented in the right anterior oblique view by segments 4 and 5 and in the left anterior oblique view by segments 8 and 9. The left anterior descending or diagonal coronary artery is represented in the right anteri.or oblique view by segments 2 and 3 and in the left anterior oblique view by segments 6 and 7. The left circumflex coronary artery is represented in the right anterior oblique view by segments 4 and 5 and the left anterior oblique view by segments 8 and 9 (Fig. 1). Percent improvement in LV function before and after thrombolytic therapy was compared by chisquare analysis. To compare the proportion of patients who showed improvement in the left anterior oblique views with that in patients who showed improvement in the right anterior oblique views, a l-tailed sign test was used.
Results AM1 was anterior in 11 and inferior in 13 patients. The infarct-related artery was the right coronary artery in 12 patients, left anterior descending or a large diagonal coronary artery in 11 and left circumflex coronary artery in 1 patient. Reperfukion was successful in 17 of the 24 patients (71%). After successful reperfusion, the mean visual estimated luminal diameter residual stenosis was 85%. In 7 patientsl29%], the artery remained occluded. Of the 17 patients with successful reperftiion, .I1 (64%) showed improvement in regional LV function [Fig. 2). In contrast, of the 7 patients with unsuccessful reperfusion, 3 (43%) showed improvement in regional LV function (p = 0.39). There was a trend toward more improved LV regional function with early successful reperfusion, but it did not reach statistical significance. Of the 5 patients with successful reperfusion within 4 hours of pain on-
8
RAO
LAO
FlGURE 1. Division of left ventricle Into 5 right anterior oblique (RAO) segments (1, anterobasak 2, anterolateral; 3, apical; 4, dtaphragmatlc; 5, posterolateral) and 4 left anterior oblique (LAO) segments (8, basal septal; 7, apical septal; 8, posterolateral; 9, lateral). End-systolic and end-dlastollc segments were computerdrawn for each Coronary Artery Surgery Study segment. The hemlsegments were divided so that each of regions 1 through 5 In the right anterior oblique view encompassed 20 hemlsegments and each of regions 8 through 9 in Ihe left anterior oblique view encompassed 25 hemisegments. These segments (end-systole, ///; enddiastole, \\\) are drawn for segments 2 and 8.
improved Regional left ventricular function
11
No improvement
3
64%
43%
6
4
n=17
n=7
Yes
No
Reperfusion FIGURE 2. Ftelatlon between Improvement lar function and outcome of reperfuslon
In reglonal left ventrlcu(computer analysis).
April 1, 1987
set, 4 (SO%] had regional wall improvement in a LV segment supplied by the infarct-related artery. Of the 7 patients with unsuccessful reperfusion, 3 (43%) had improvement in regional LV function (p = 0.6). Of the 12 with successful reperfusion more than 4 hours after symptom onset, 7 (58%) had improved regional LV function. The changes in LV regional wall function were compared in the 30° right anterior oblique view, 60’ left anterior oblique view and both views (Fig. 3). Of 11 patients with left anterior descending artery occlusion, improvement in regional LV function was seen in 4 in the right anterior oblique view alone, in 5 in the left anterior oblique view alone and in 7 when both views were assessed. In the 12 patients with right coronary occlusions, the left anterior oblique view documented improvement in regional LV function in 6 and the right anterior oblique view showed improvement in only 1 patient (p
Discussion Coronary disease produces heterogeneous effects on LV function so that reliance on global measures of ventricular function alone may be inadequate.17J8
THE AMERICAN
TABLE I Relation in 24 Patients
JOURNAL
OF CARDIOLOGY
Between
Ejection
Fraction
Location
Successful reperfusion increased EF Increased (>5%) EF, successful reperfusion
Volume
59
795
and Reperfusion
of Occlusion
LAD (n = 11)
Right
LC
(n = 12)
(n = 1)
8
0
1
5 418
4 41.5
1 111
EF = ejection fraction; LAD = left anterior descending artery; circumflex artery: n = number of patients; Right = right coronary
LC = left artery.
AM1 exaggerates the problem of assessment of LV function because some non-infarct-related segments may be hyperkinetic and partially cancel the effects of the hypokinetic infarcted areas.lgJO Early studies documented the importance of analyzing biplane angiograms in patients with chronic coronary artery disease.18J1 The left anterior oblique view offers information about the septal and posterolateral walls, which are not seen when only the right anterior oblique view is used. This view is particularly important with circumflex coronary artery occlusions. Despite these issues, there is debate as to the need for analysis of biplane regional LV function for gauging the effect of thrombolytic therapy during AMLz2 Assessment of regional LV function is complex. Although several mathematical and projection models can be used for both tine and radionuclide LV angiography, 7~18~*g~23~24 none is ideal. We use a centerline method and measure percent hemisegment shortening from the centerline. The centerline and hemisegments are recorded in both views separately for end diastole and end systole. With this method, systolic movement of the whole heart is accounted for by allowing the long axis to act as a moving reference system to adjust
Patients, 0 I
3 I
6 I
no. 9 I
12 I
RAO LAO Combination RAO LAO Combination
Improvement
FIGURE 3. Change in regional left ventricular functlon In right anterlor oblique (RAO) view, left anterior obllque (LAO) view and both views (computer analysis). When only the RAO view was used, 5 patients (21%) showed Improvement In reglonal LV function; when biplane views were used, 14 (55%) showed Improvement. Clrc = circumflex coronary artery; LAD = left anterlor descending coronary artery; RCA = right coronary artery.
796
ASSESSMENT
OF REGIONAL
TABLE
II
WALL
MOTION
Calculated
Data
for Patient
with
lnferlor
InfarctIon’ Segment
1
Time of Study
2 Average
Baseline IO-day
34 50
4
3
28 34
% Hemisegment 25 28 Deviation
Baseline 1O-day
-0.62 0.15
-0.86 -0.56
-1.72 -1.35
5
-1.38 -1.59
7
0
9
14 51
6 40
24 41
0 34
Shortening
26 23 from
6
22 14 Normalt -0.53 -1.05
-0.88 1.25
-1.82 0.48
-1.75 -0.31
-2.35 -0.15
l Angiograms of this patient are shown in Figure 4. TAverage hemisegment shortening for each segment was defined as the amount of deviation from normal expressed in standard deviations. The deviation for the specific segment was the average hemlsegment shortening obtained in normal controls minus the hemisegment shortening In the patient divfded by the normal standard devlation for that specific segment. As defined, improvement was an increase in average hemisegment shortening of 10.5 standard deviation from normal. In this patlent. improvement was noted In segments 6 through 9.
for motion of the heart and of the patient, which are independentof the actualshorteningof the myocardial fibers. Also, to adjust for the effects of global ventricular function on regional function, we relate average hemisegment shortening in patients to that in normal control subjects. In addition to concernsaboutthe mathematical formula selectedfor analysis,it may be difficult to relate the site of arterial occlusion to a specific LV segment. There is a correlationbetweenthe location of coronary arterial narrowing and regional wall motion abnormalities in patientswith AMI.13-16J8 The CoronaryArtery SurgeryStudy usesLV segmentscorrespondingto frequently involved arterial segments:inferior or lateral segmentsin both views are related to the right or
FIGURE 4. Left ventricular anglograms of a patient with dlastole (fop) and systole (hffom) lmmedlately before segments (segments 4 and 5) show marked hypoklnesla. Regional wall motlon showed llttle change from the Initial and systole (bottom) lmmedlately before thrombolytic reperfuslon. Systolic function markedly Improved, severe 10 days.
the circumflex coronary artery, and anterior and apical septal segmentsare related to a left anterior descendingor diagonal coronary artery. Variability and overlap, however, do exist, so sequential changesin regional function must be analyzed in the same segments from baseline to follow-up. In this study,recoveryof LV function after attempted reperfusionwas variable. With earlier reperfusion, a larger percentageof patients had improvement in regional LV function. With reperfusionwithin 4 hours of pain onset,4 of 5 patients showed improvement. A similar proportion with successful reperfusion of either the right or the left anterior descendingcoronary artery showed improvement in global ejection fraction.
lnferlor acute myocardlal Infarction. A, right anterior obllque (RAO) vlews. Leff, thrombolytlc therapy. Anterior wall motion ls well preserved, but lnferlor wall R&h& dlastole (fop) and systole (boffom) 10 days after successful WdUSiOn. to the follow-up study. B, left anterlor oblique (LAO) views. reff, dlastole (fop) therapy. R/g/M, dlastole (fop) and systole (boffom) 10 days after successful hypoklnesla was noted before reperfuslon, but function was relatively normal at
April I,1987
Use of regional wall analysis with biplane projection views added clinically important information. Only 5 of the 24 patients showed regional LV improvement when the right anterior oblique view was used, but 14 showed regional LV improvement when biplane wall motion analysis was used. Of 12 patients with right coronary artery occlusion, only 1 patient showed improvement in the right anterior oblique view. In contrast, 6 of 12 patients showed improvement in 1 or 2 regional segments in the left anterior oblique view. For the 24 patients as a whole, more showed improvement in the left anterior oblique segments. Both views, however, offered complementary information. Two patients showed improvement only in a right anterior oblique segment and 9 showed improvement in the left anterior oblique segments alone. In the 1 patient with circumflex coronary artery occlusion, improvement was identified in only the left anterior oblique view. The posterolateral wall segment supplied by the circumflex artery may be missed with only monoplane right anterior oblique LV views20 Assessment of LV function with the monoplane right anterior oblique view may therefore underestimate improvement in function after lytic therapy. Limitations: Biplane projection analysis has limitations. Standard left anterior oblique views foreshorten septal segments. Angulated views minimize this problem. However, with left anterior oblique cranial angulation, the lower apical septal and posterolateral segments may be superimposed on the diaphragm, making analysis difficult. In addition, normal values for wall motion are not available for such projection views. Finally, specific LV wall segments and the arterial branches involved may show variability. Serial studies of regional function in the same patient minimize this problem. Irrespective of these limitations, biplane projection views for assessment of regional LV wall motion add significant information to that obtained by monoplane right anterior oblique assessment. The projections are complementary, adding information about regional function not obtained by either view alone.
References 1. Kennedy IW, Ritchie JL, Davis KB, Fritz Jr<. Western Washington Randomized Trial of Intracoronary Streptokinase in Acute Myocordial Infarction. N Engl 1 Med 1983;309:1477-1482. 2. Simoons ML, Serruys PW, van den Brand M, Biir F, de Zwaan C, Res J. Verheugt FWA, Krauss XH, Remme WJ, Vermeer F, Lubsen 1. Improved survival after early thrombolysis in acute myocardial infarction: a randomised trial by the Interuniversity Cardiology Institute in The Netherlands. Lancet 1985;2:578-581.
THE AMERICAN
JOURNAL
OF CARDIOLOGY
Volume
59
797
3. Rentrop P. Smith H, Painter L. Holt J. Changes in left ventricular ejection fraction after intracoronary thrombolytic therapy: results of the Registry of the European Society of Cardiology. Circulation 1983;68:suppl I:I-55-I-59. 4. Leiboff RH. Katz. Rj, Wasserman AG. Bren GB, Schwartz H, Varghese Pj, Ross AM. A randomized, angiographically controlled trial of intracoronary streptokinase in acute myocardial infarction. Am 1 Cardiol 1984;53:404-407. 5. Anderson IL. Marshall HW, Bray BE, Lutz JR, Frederick PR. Yanowitz FG, Datz FL, Klausner SC, Hagan AD. A randomized trial of introcoronary streptokinase in the treatment of acute myocardial infarction. N Engl r Med 1983;308:1312-1318, 6. Khaia F, Walton IA Ir, Brvmer FT. Lo E, Osterberger L, O’Neill WW, Colfer HT, W&s R, Lee T..K&ian ?, Goldberg AD, Pitt B, Goldstein S. Intracoronary fibrinolytic therapy in acute myocardial infarction. Report of a prospective randomized trial. N Engl 1 Med 1983;308:1305-1311, 7. Sheehan FH, Mathey DG, Schafer 1, Dodge HT. Balson EL. Factors that determine recovery of left ventricular function after thrombolysis in patients with acute myocardial infarction. Circulation 1985;71:1121-1128. 6. Koren G. Weiss AT, Hasin Y, Appelbaum D, Welber S, Rozenman Y, Lotan C, Mosseri M, Sapoznikov D, Luria MH. Gotsman MS. Prevention of myocardial domage in acute myocardial ischemia by early treatment with intravenous streptokinase. N Engl [ Med 1985;313:1384-1389. 9. TIM1 Study Group. The Thrombolysis in Myocardial Infarction (TIMI) trial: phase I findings. N Engl 1 Med 1985:312:932-936. 10. Holmes DR, Bove AA, Wondrow MA, Gray JE. Video x-ray progressive scanning: new technique for decreasing x-ray exposure without decreasing image quality during cardiac catheterization. Mayo Clin Proc 1986:61:321326.
11. Bove AA, Kreulen TH, Spann JF. Computer analysis of left ventricular dynamic geometry in man. Am 1 Cardiol 1978;41:1239-1248. 12. Principal Investigators of CASS and Their Associates. The National Heart, Lung, and Blood Institute Coronary Artery Surgery Study (CA%]. Circulation 1981;63:suppl 1:&1-I-81. 13. Williams RA, Cohn PF, Vokonas PS, Young E, Herman MV, Gorlin R. Electrocardiographic, arteriographic and ventriculographic correlations in transmural myocardial infarction. Am f Cardiol 1973;31:595-599. 14. Herman MV. Heinle RA, Klein MD, Gorlin R. Localized disorders in myocardial contraction: asynergy and its role in congestive heart failure. N Engl r Med 1967;277:222-232. 15. Savage RM, Wagner GS, Ideker RE, Podolsky SA, Hackel DB. Correlation of postmortem anatomic findings with electrocardiographic changes in patients with myocardial infarction: retrospective study of patients with typical anterior and posterior infarcts. Circulation 1977;55:279-285. 16. Bodenheimer MM, Banka VS, Helfant RH. Q waves and ventricular asynergy: predictive value and hemodynamic significance of anatomic localization. Am 1 Cardiol 1975;35:615-618. 17. Cohn PF, Herman MV, Gorlin R. Ventricular dysfunction in coronary artery disease. Am \ Cardiol 1974;33:307-310. lg. Herman MV, Gorlin R. In vivo angiagraphic pathoanatomy of the acute syndromes of coronary heart disease. Trans Assoc Am Physicians 1972;85: 231-246.
19. Sheehan FH, Mathey DG, Schafer 1, Krebber HJ, Dodge HT. Effect of interventions in salvaging left ventricular function in acute infarction: a study of introcoronary streptokinase. Am r Cardiol 1983;52:431-438. 20. Stack RS, Phillips HR III, Grierson DS, Behar VS. Kong Y. Peter RH, Swain JL. Greenfield JC Jr. Functional improvement of jeopardized myocardium following introcoronary streptokinase infusion in acute myocardial infarction. J Clin invest 1983;72:84-95. 21. Cohn PF, Gorlin R, Adams DF, Chahine RA, Vokonas PS, Herman MV. Comparison of biplane and single plane left ventriculograms in patients with coronary artery disease. Am 1 Cardiol 1974;33:1-6. 22. Sheehan FH, Schafer J, Dodge HT. Wygant J, Mitten S, Bolson EL. RAO vs LAO regional wall motion changes in post-thrombolysis patients (abstr]. Circulation i985;72:suppl rrr:rrr-22. 23. Ohsuzu F, Boucher CA, Newell JB. Yasuda T, Gold HK, Leinbach RC. McKusick KA, Okada RD. Rosenthal S, Pohost GM, Strauss HW. Relation of segmental wall motion to global left ventricular function in acute myocardial infarction. Am J Cardiol 1983;51:1275-1281. 24. Neumann P. Schicha H, Tebbe U, Kreuzer H, Emrich D. Analysis of left ventricular regional motility: a comparison of different methods. Eur J Nucl Med 1984;9:205-208.
Regional left ventricular (LV) function was assessed using serial biplane orthogonal LV angiograms recorded before and after repetfusion therapy for acute myocardial infarction (AMI) in 24 patients. Improvement in regional LV function was seen in only 5 patients after reperfu&n therapy when only the right anterior oblique view was analyzed; improvement in regional wall motion was seen in 14 when biplane views were analyzed. Biplane analysis was particularly important in the 12 patients with right coronary artery occlusion, amoq whom the
A
lthough improved mortality and morbidity rates have been documented with reperfusion therapy during acute myocardial infarction (AMI), quantification of myocardial salvage is difficult.1-8 Because the hallmarks of coronary artery disease are regional ischemia and localized contraction abnormalities, reliance on global left ventricular (LV) function may be insufficient. Also, reliance on only 1 angle of view for left ventriculography may underestimate the effects of reperfusion on LV function. We assessed LV function before and after reperfusion for AM1 using serial biplane orthogonal LV angiograms, and evaluated the independent contributions of right anterior oblique and left anterior oblique views for assessing changes in regional LV function. From the Division of Cardiovascular Diseases and Internal Medicine, the Department of Physiology and Biophysics, and the Section of Information Processing and Systems, Mayo Clinic and Mayo Foundation, Rochester, Minnesota. Manuscript received August 4, 1986; revised manuscript received November 24,1986, accepted November 25.1986. Address for reprints: David R. Holmes, Jr., MD, Mayo Clinic, 200 First Street SW, Rochester, Minnesota 55905.
ri9ht anterior oblique view showed improvement in only 1 patient but the left anterior oblique view showed improverr?ent In 6 patients (p <0.05). Biplane analysis is more sensitive than monoplane right ante&r oblique analysis alone for detecting improvement in LV function after repetfusion therapy for AM. However, both views are complementary, adding information about regional function not revealed by either view alone. (Am J Cardiol 1967;59:793-797)
Methods Patients: The population consisted of 24 patients (20 men, 4 women) sequentially enrolled in the Multicenter Thrombolysis in Myocardial Infarction Trial, which evaluated the relative efficacy of tissue plasminogen activator and streptokinase during AMI.g In all patients baseline LV and coronary angiograms were recorded immediately before administration of the thrombolytic agent and 10 days after attempted reperfusion. The specific projection angles for coronary and LV angiograms recorded at the initial study were reproduced at the lo-day study. Left ventricular angiography and function: Biplane %-mm tine left ventriculograms, 30” right anterior oblique and 60’ left anterior oblique views, were recorded at a rate of 30 frames/s; biplane video recordings using progressive scanning were obtained simultaneously.1° Hemiaxial views were not used. AngiovisP (45 ml) was injected (13 to 15 ml/s) with a multiple sidehole catheter placed retrogradely into the left ventricle. The second or third beat after contrast injection was analyzed; no post-ventricular premature beats were used. Representative end-systolic and end-diastolic video frames at baseline and follow-up studies were de-
794
ASSESSMENT
OF REGIONAL
WALL
MOTION
fined in both the 30° right anterior oblique and 60’ left anterior oblique views as the smallest and largest LV volumes. These video frames were displayed for image analysis in a computer image-processing system (General Electric DF.3009 and IPDC). The apex and the midportion of the aortic valve were identified in each view at end systole and end diastole, thus defining the long axis of the left ventricle? The endocardial surface was then scanned with a computer-generated trackball video cursor to create an outline of the LV cavity. This method allows visual confirmation that the traced outline coincides with the ventricular silhouette. The generated coordinates are transferred in real time to the computer and stored on a magnetic disk. After tracing the long axis and endocardial outline, the X-Y coordinate pairs are used to determine 50 diameters perpendicular to the long axis in the right and left anterior oblique views (Fig. 1). Simpson’s rule was used to calculate ventricular volume and biplane ejection fraction.11 For regional analysis, the biplane images of the left ventricle were separated into 9 regions, as defined by the Coronary Artery Surgery Study.12 Segments 1 through 5 are represented in the right anterior oblique view and segments 6 through 9 in the left anterior oblique view [Fig. 1). The hemisegment percent shortening was defined as [(end-diastolic length - endsystolic length)/end-diastolic length]. Mean shortening for a region was calculated as the average shortening of all hemisegments in that region. Fourteen normal patients evaluated for chest pain of uncertain origin who had normal coronary arteries served as control subjects. Average hemisegment shortening for each segment was defined as average hemisegment shortening in the control subjects minus hemisegment shortening in the patients divided by the normal standard deviation for that specific segment.”
Improvement was defined as ati increase in avetage hemisegment shortening of 0.5 standard deviation or more from normal in the regional LV segment before and 10 days after reperfusion.. Previous studies evaluated the relation of the arterial segment, electrocardiographic documentation of AM1 location and ‘regional wall motion abnormalities.13-16 We related arterial blood supply and the regional wall segment to correlate changes with the occluded artery. With the scheme selected, the right coronary artery is represented in the right anterior oblique view by segments 4 and 5 and in the left anterior oblique view by segments 8 and 9. The left anterior descending or diagonal coronary artery is represented in the right anteri.or oblique view by segments 2 and 3 and in the left anterior oblique view by segments 6 and 7. The left circumflex coronary artery is represented in the right anterior oblique view by segments 4 and 5 and the left anterior oblique view by segments 8 and 9 (Fig. 1). Percent improvement in LV function before and after thrombolytic therapy was compared by chisquare analysis. To compare the proportion of patients who showed improvement in the left anterior oblique views with that in patients who showed improvement in the right anterior oblique views, a l-tailed sign test was used.
Results AM1 was anterior in 11 and inferior in 13 patients. The infarct-related artery was the right coronary artery in 12 patients, left anterior descending or a large diagonal coronary artery in 11 and left circumflex coronary artery in 1 patient. Reperfukion was successful in 17 of the 24 patients (71%). After successful reperfusion, the mean visual estimated luminal diameter residual stenosis was 85%. In 7 patientsl29%], the artery remained occluded. Of the 17 patients with successful reperftiion, .I1 (64%) showed improvement in regional LV function [Fig. 2). In contrast, of the 7 patients with unsuccessful reperfusion, 3 (43%) showed improvement in regional LV function (p = 0.39). There was a trend toward more improved LV regional function with early successful reperfusion, but it did not reach statistical significance. Of the 5 patients with successful reperfusion within 4 hours of pain on-
8
RAO
LAO
FlGURE 1. Division of left ventricle Into 5 right anterior oblique (RAO) segments (1, anterobasak 2, anterolateral; 3, apical; 4, dtaphragmatlc; 5, posterolateral) and 4 left anterior oblique (LAO) segments (8, basal septal; 7, apical septal; 8, posterolateral; 9, lateral). End-systolic and end-dlastollc segments were computerdrawn for each Coronary Artery Surgery Study segment. The hemlsegments were divided so that each of regions 1 through 5 In the right anterior oblique view encompassed 20 hemlsegments and each of regions 8 through 9 in Ihe left anterior oblique view encompassed 25 hemisegments. These segments (end-systole, ///; enddiastole, \\\) are drawn for segments 2 and 8.
improved Regional left ventricular function
11
No improvement
3
64%
43%
6
4
n=17
n=7
Yes
No
Reperfusion FIGURE 2. Ftelatlon between Improvement lar function and outcome of reperfuslon
In reglonal left ventrlcu(computer analysis).
April 1, 1987
set, 4 (SO%] had regional wall improvement in a LV segment supplied by the infarct-related artery. Of the 7 patients with unsuccessful reperfusion, 3 (43%) had improvement in regional LV function (p = 0.6). Of the 12 with successful reperfusion more than 4 hours after symptom onset, 7 (58%) had improved regional LV function. The changes in LV regional wall function were compared in the 30° right anterior oblique view, 60’ left anterior oblique view and both views (Fig. 3). Of 11 patients with left anterior descending artery occlusion, improvement in regional LV function was seen in 4 in the right anterior oblique view alone, in 5 in the left anterior oblique view alone and in 7 when both views were assessed. In the 12 patients with right coronary occlusions, the left anterior oblique view documented improvement in regional LV function in 6 and the right anterior oblique view showed improvement in only 1 patient (p
Discussion Coronary disease produces heterogeneous effects on LV function so that reliance on global measures of ventricular function alone may be inadequate.17J8
THE AMERICAN
TABLE I Relation in 24 Patients
JOURNAL
OF CARDIOLOGY
Between
Ejection
Fraction
Location
Successful reperfusion increased EF Increased (>5%) EF, successful reperfusion
Volume
59
795
and Reperfusion
of Occlusion
LAD (n = 11)
Right
LC
(n = 12)
(n = 1)
8
0
1
5 418
4 41.5
1 111
EF = ejection fraction; LAD = left anterior descending artery; circumflex artery: n = number of patients; Right = right coronary
LC = left artery.
AM1 exaggerates the problem of assessment of LV function because some non-infarct-related segments may be hyperkinetic and partially cancel the effects of the hypokinetic infarcted areas.lgJO Early studies documented the importance of analyzing biplane angiograms in patients with chronic coronary artery disease.18J1 The left anterior oblique view offers information about the septal and posterolateral walls, which are not seen when only the right anterior oblique view is used. This view is particularly important with circumflex coronary artery occlusions. Despite these issues, there is debate as to the need for analysis of biplane regional LV function for gauging the effect of thrombolytic therapy during AMLz2 Assessment of regional LV function is complex. Although several mathematical and projection models can be used for both tine and radionuclide LV angiography, 7~18~*g~23~24 none is ideal. We use a centerline method and measure percent hemisegment shortening from the centerline. The centerline and hemisegments are recorded in both views separately for end diastole and end systole. With this method, systolic movement of the whole heart is accounted for by allowing the long axis to act as a moving reference system to adjust
Patients, 0 I
3 I
6 I
no. 9 I
12 I
RAO LAO Combination RAO LAO Combination
Improvement
FIGURE 3. Change in regional left ventricular functlon In right anterlor oblique (RAO) view, left anterior obllque (LAO) view and both views (computer analysis). When only the RAO view was used, 5 patients (21%) showed Improvement In reglonal LV function; when biplane views were used, 14 (55%) showed Improvement. Clrc = circumflex coronary artery; LAD = left anterlor descending coronary artery; RCA = right coronary artery.
796
ASSESSMENT
OF REGIONAL
TABLE
II
WALL
MOTION
Calculated
Data
for Patient
with
lnferlor
InfarctIon’ Segment
1
Time of Study
2 Average
Baseline IO-day
34 50
4
3
28 34
% Hemisegment 25 28 Deviation
Baseline 1O-day
-0.62 0.15
-0.86 -0.56
-1.72 -1.35
5
-1.38 -1.59
7
0
9
14 51
6 40
24 41
0 34
Shortening
26 23 from
6
22 14 Normalt -0.53 -1.05
-0.88 1.25
-1.82 0.48
-1.75 -0.31
-2.35 -0.15
l Angiograms of this patient are shown in Figure 4. TAverage hemisegment shortening for each segment was defined as the amount of deviation from normal expressed in standard deviations. The deviation for the specific segment was the average hemlsegment shortening obtained in normal controls minus the hemisegment shortening In the patient divfded by the normal standard devlation for that specific segment. As defined, improvement was an increase in average hemisegment shortening of 10.5 standard deviation from normal. In this patlent. improvement was noted In segments 6 through 9.
for motion of the heart and of the patient, which are independentof the actualshorteningof the myocardial fibers. Also, to adjust for the effects of global ventricular function on regional function, we relate average hemisegment shortening in patients to that in normal control subjects. In addition to concernsaboutthe mathematical formula selectedfor analysis,it may be difficult to relate the site of arterial occlusion to a specific LV segment. There is a correlationbetweenthe location of coronary arterial narrowing and regional wall motion abnormalities in patientswith AMI.13-16J8 The CoronaryArtery SurgeryStudy usesLV segmentscorrespondingto frequently involved arterial segments:inferior or lateral segmentsin both views are related to the right or
FIGURE 4. Left ventricular anglograms of a patient with dlastole (fop) and systole (hffom) lmmedlately before segments (segments 4 and 5) show marked hypoklnesla. Regional wall motlon showed llttle change from the Initial and systole (bottom) lmmedlately before thrombolytic reperfuslon. Systolic function markedly Improved, severe 10 days.
the circumflex coronary artery, and anterior and apical septal segmentsare related to a left anterior descendingor diagonal coronary artery. Variability and overlap, however, do exist, so sequential changesin regional function must be analyzed in the same segments from baseline to follow-up. In this study,recoveryof LV function after attempted reperfusionwas variable. With earlier reperfusion, a larger percentageof patients had improvement in regional LV function. With reperfusionwithin 4 hours of pain onset,4 of 5 patients showed improvement. A similar proportion with successful reperfusion of either the right or the left anterior descendingcoronary artery showed improvement in global ejection fraction.
lnferlor acute myocardlal Infarction. A, right anterior obllque (RAO) vlews. Leff, thrombolytlc therapy. Anterior wall motion ls well preserved, but lnferlor wall R&h& dlastole (fop) and systole (boffom) 10 days after successful WdUSiOn. to the follow-up study. B, left anterlor oblique (LAO) views. reff, dlastole (fop) therapy. R/g/M, dlastole (fop) and systole (boffom) 10 days after successful hypoklnesla was noted before reperfuslon, but function was relatively normal at
April I,1987
Use of regional wall analysis with biplane projection views added clinically important information. Only 5 of the 24 patients showed regional LV improvement when the right anterior oblique view was used, but 14 showed regional LV improvement when biplane wall motion analysis was used. Of 12 patients with right coronary artery occlusion, only 1 patient showed improvement in the right anterior oblique view. In contrast, 6 of 12 patients showed improvement in 1 or 2 regional segments in the left anterior oblique view. For the 24 patients as a whole, more showed improvement in the left anterior oblique segments. Both views, however, offered complementary information. Two patients showed improvement only in a right anterior oblique segment and 9 showed improvement in the left anterior oblique segments alone. In the 1 patient with circumflex coronary artery occlusion, improvement was identified in only the left anterior oblique view. The posterolateral wall segment supplied by the circumflex artery may be missed with only monoplane right anterior oblique LV views20 Assessment of LV function with the monoplane right anterior oblique view may therefore underestimate improvement in function after lytic therapy. Limitations: Biplane projection analysis has limitations. Standard left anterior oblique views foreshorten septal segments. Angulated views minimize this problem. However, with left anterior oblique cranial angulation, the lower apical septal and posterolateral segments may be superimposed on the diaphragm, making analysis difficult. In addition, normal values for wall motion are not available for such projection views. Finally, specific LV wall segments and the arterial branches involved may show variability. Serial studies of regional function in the same patient minimize this problem. Irrespective of these limitations, biplane projection views for assessment of regional LV wall motion add significant information to that obtained by monoplane right anterior oblique assessment. The projections are complementary, adding information about regional function not obtained by either view alone.
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