Effect of Parent Coronary Arterial Occlusion On Left Ventricular Function After Aortocoronary Bypass Surgery
PETER STEELE, MD DENNIS BATTOCK, MD, FACC GEORGE PAPPAS, MD ROBERT VOGEL, MD Denver, Colorado
From the Division of Cardiology, Department of Medicine and the Department of Surgery, Denver Veterans Administration Hospital, University of ColoradoMedicalCenter,Denver,Colo. This studywas supportedby researchfundsof the Veterans Administration. Manuscript received February 10, 1976; revised manuscript received June 25, 1976, acceptedJune 30, 1976. Addressfor reprints: PeterSteele, MD, Denver Veterans Administration Hospital, 1055Clermont, Denver, Colo. 80220.
In 62 men with open parent coronary arteries who underwent saphenous vein aortocoronary bypass to either the right or left anterior descending coronary artery, or both, left ventricular ejection fraction and wall motion of the anterior and inferior segments of the left ventricle were measured before and after (average 11 months) the operation. Of 34 left ventricular segments with open vein grafts and open parent coronary arteries, 91 percent were unaltered by the operation, none were in worse condition and 9 percent showed improved wall movement. Among 33 segments with open grafts but new total occlusion of the parent coronary arteries, 67 percent were unaltered, whereas the condition of 18 percent was worse and of 15 percent was improved. Among 21 segments with closed grafts but patent parent arteries, the condition of 29 percent was unchanged and of 71 percent was worse; among 14 segments with occlusion of both grafts and parent arteries the condition of 29 percent was unchanged and of 71 percent was worse. In 10 men with patency of all vein grafts and parent arteries, left ventricular ejection fraction was not altered (0.55 4- 0.03 to 0.53 -I- 0.04 [average -I- standard error of the mean]) and in 11 with all grafts open but all parent arteries occluded left ventricular ejection fraction was unchanged (0.51 -I- 0.02 to 0.54 4- 0.03). Left ventricular ejection fraction was decreased in eight men with occlusion of all vein grafts whether or not occlusion of the parent coronary arteries had occurred. The results suggest that occlusion of the parent coronary arteries in the presence of a patent vein graft does not unfavorably alter left ventricular ejection fraction or segmental wall motion, whereas graft occlusion is associated with deterioration of left ventricular ejection fraction and segmental motion whether or not the parent artery is also occluded.
Saphenous vein aortocoronary bypass surgery is frequently performed, and the results have been encouraging in relation to relief of angina and reduction in mortality. Vein graft occlusion occurs in about 20 percent of grafts, 1 and this event has been associated with recurrence of angina and a decrease in left ventricular performance. 2 In addition, progression of proximal coronary arterial obstruction to occlusion in grafted vessels has been observed in 24 to 67 percent of cases3-7 and has been associated with recurrence of angina 4,5 although this point has been ~lisputed. 6,7 Concern for the consequences of progression of proximal coronary disease in grafted arteries is appropriate, but relatively little information is available with respect to alteration of left ventricular function in association with proximal occlusion of the parent coronary artery. In this study left ventricular ejection fraction and segmental wall motion were analyzed before and after coronary bypass surgery in a group of patients in whom the status of both the saphenous vein grafts and the native coronary circulation was defined.
January 1977 The American Journal of CARDIOLOGY Volume39
39
vENTRICULAR FUNCTION AFTER CORONARY BYPASS--STEELE ET AL.
Patients
Sixty-two men (average age 52 years, range 29 to 62 years) with coronary artery disease were studied. All underwent aortocoronary bypass with saphenous veins constructed to either the distal right (9 men), distal left anterior descending (13 men) or both coronary arteries (40 men). No patient had obstruction of more than 40 percent of luminal diameter in the main left or circumflex artery or any of the marginal branches. All grafted coronary arteries had obstructions of 60 to 95 percent of luminal diameter. All patients underwent coronary bypass surgery for the relief of angina. Postoperative cardiac catheterization was undertaken in all cases to evaluate the results of operation, and in some cases because of postoperative myocardial infarction or recurrence of angina. The postoperative study was performed 4 to 27 months (average 11 months) after the bypass procedure.
the long axis of the end-systolic silhouette was quadrisected to form eight chords, four reflecting wall motion of the anterior and four of the inferior wall of the left ventricle (Fig. 1). The percent shortening of each chord was determined and the sum of chords I to 4 that reflected movement of the anterior wall was computed. The sum of the percent shortening of chords 5 to 8 reflected movement of the inferior wall. The long a x i s used for wall motion analysis was also used to calculate ejection fraction and the same cardiac cycle was used for both calculations. The heart rate recorded during the preoperative cineventriculogram was within 20 percent of the rate recorded during postoperative ventriculography. N o r m a l v a l u e s : In 21 normal men (with normal coronary arteriograms) left ventricular ejection fraction averaged 0.66 (range 0.57 to 0.77 [4-2 standard deviations]). Wall motion analysis yielded values for shortening (4-2 standard deviations) along the eight chords of:
Methods
Chord Chord Chord Chord
Cardiac catheterization was undertaken with patients in the postabsorptive state with either no or mild sedation (diazepam 10 to 15 mg orally, and diphenhydramine hydrochloride, 25 to 50 mg orally) and with use of the percutaneous femoral arterial or brachial arterial cut-down approach. Left ventricular cineangiograms were filmed at 60 frames/sec in the 30 to 40 ° right anterior oblique projection after power injection of 32 to 40 ml of 76 percent meglumine and sodium z diatriazoates 76 percent (Renografin®-76, Squibb) over 4 seconds. Either a no. 8F pigtail or a no. 7F National Institutes of Health (Cordis) catheter was used for the ventriculogram. Selective coronary and vein graft injections of contrast medium in multiple projections were performed with either preformed femoral-coronary, brachial-coronary or Sones catheters. Left ventricular ejection fraction (LVEF) was calculated from the left ventricular end-diastolic volume (LVEDV) and the ventriculographic stroke volume (SV) as: SV LVEF - - (1) LVEDV where stroke volume was computed as the difference between left ventricular end-diastolic and end-systolic volumes. Left ventricular volumes were computed from the projected end-diastolic and end-systolic areas (A) and the long axis (aortic valve to left ventricular apex) (L) s,9 as: LVEDV = ~/6 LM 2
1--55 3--54 5--55 7--40
4- 25%; Chord 2--57 4- 24% 4- 27%; Chord 4--59 4- 30% 4- 20%; Chord 6 46 4- 19% 4- 11%; Chord 8--28 4- 26%
These data agree with values observed in normal subjects by Leighton et al. ]° Means of the various groups were compared with Student's paired t test. Results
T h e 62 men had 102 s a p h e n o u s vein grafts constructed to either the distal left anterior descending (53 grafts) or the distal right c o r o n a r y a r t e r y (49 grafts). F o r t y men h a d b o t h arteries grafted. T h u s , 102 segm e n t s (53 anterior, 49 inferior) in these 62 m e n were analyzed, and ejection fraction was determined for each of the 62 men. Segmental wall m o t i o n was n o r m a l preoperatively in 43 segments and abnormal in 59. Ejection fraction was n o r m a l before c o r o n a r y bypass surgery in
(2)
where M is the minor axis, calculated from the area and the long axis as: M = 4_A_A ~L
(3)
Cardiac cycles selected for analysis included only those within the first four occurring after injection, of contrast medium. Beats following premature beats were avoided. Calculations were performed with the assistance of an X-Y digitizer and a digital computer. Left ventricular segmental wall motion was measured using the method of Leighton et al. 1° The projected silhouette at end-diastole in the right anterior oblique view was drawn and a long axis constructed from the apex to a point on theaortic valve so that the two areas of the bisected left ventricle obtained with planimetry agreed within 1 cm2 of each other. The end-systolic silhouette was drawn and a long axis constructed from the aortic valve to the apex using the same point on the aortic valve as used for the end-diastolic long axis. The long axes were superimposed (to correct for systolic rotation) and
40
January 1977
The American Journal of CARDIOLOGY
'\
/
Segmental = OE-ES wall motion OE-L
N/\
x 100
FIGURE 1. Representative normal left ventricular silhouettes (right anterior oblique) at end-systole and end-diastole with the eight chords defining segmental contraction (method of Leighton et al.l°). Percent shortening of chord 4 was computed as the distance from the onset of ejection (OE) to end-systole (ES) divided by the distance from the onset of ejection to the long axis (L).
Volume 39
VENTRICULAR FUNCTION AFTER CORONARY BYPASS--STEELE ET
TABLE I
T A B L E II
Effect of Occlusion of the Parent Coronary Artery on Segmental Wall Motion in 62 Men
Effect of Occlusion of the Parent Coronary Artery on Ejection Fraction
Men-
Ventricular Left-Ventricular Ejection Fraction Seg- (average +- standard error of the mean)
Postoperative Left Ventricular Segmental Wall Motion (compared with preoperative value)
tricular Unchanged Segments no. % (no.)
Worse no.
%
ments
Improved no. %
(no.) Preoperative Postoperative
34
31
91
0
0
33
22
67
6
18
21
6
29
15
71
0
0
14
4
29
10 71
0
0
102
63
62
31
8
8
30
3 9 5
15
P Value
All grafts open,
10
0.55 + 0.03
0.53 + 0.04
NS
All grafts open, all arteries closed* All grafts closed, all arteries open* All grafts closed, all arteries closed*
11
0.51 + 0.02
0.54 + 0.03
NS
8
0.56 + 0.02
0.41 + 0.02
P
PETER STEELE, MD DENNIS BATTOCK, MD, FACC GEORGE PAPPAS, MD ROBERT VOGEL, MD Denver, Colorado
From the Division of Cardiology, Department of Medicine and the Department of Surgery, Denver Veterans Administration Hospital, University of ColoradoMedicalCenter,Denver,Colo. This studywas supportedby researchfundsof the Veterans Administration. Manuscript received February 10, 1976; revised manuscript received June 25, 1976, acceptedJune 30, 1976. Addressfor reprints: PeterSteele, MD, Denver Veterans Administration Hospital, 1055Clermont, Denver, Colo. 80220.
In 62 men with open parent coronary arteries who underwent saphenous vein aortocoronary bypass to either the right or left anterior descending coronary artery, or both, left ventricular ejection fraction and wall motion of the anterior and inferior segments of the left ventricle were measured before and after (average 11 months) the operation. Of 34 left ventricular segments with open vein grafts and open parent coronary arteries, 91 percent were unaltered by the operation, none were in worse condition and 9 percent showed improved wall movement. Among 33 segments with open grafts but new total occlusion of the parent coronary arteries, 67 percent were unaltered, whereas the condition of 18 percent was worse and of 15 percent was improved. Among 21 segments with closed grafts but patent parent arteries, the condition of 29 percent was unchanged and of 71 percent was worse; among 14 segments with occlusion of both grafts and parent arteries the condition of 29 percent was unchanged and of 71 percent was worse. In 10 men with patency of all vein grafts and parent arteries, left ventricular ejection fraction was not altered (0.55 4- 0.03 to 0.53 -I- 0.04 [average -I- standard error of the mean]) and in 11 with all grafts open but all parent arteries occluded left ventricular ejection fraction was unchanged (0.51 -I- 0.02 to 0.54 4- 0.03). Left ventricular ejection fraction was decreased in eight men with occlusion of all vein grafts whether or not occlusion of the parent coronary arteries had occurred. The results suggest that occlusion of the parent coronary arteries in the presence of a patent vein graft does not unfavorably alter left ventricular ejection fraction or segmental wall motion, whereas graft occlusion is associated with deterioration of left ventricular ejection fraction and segmental motion whether or not the parent artery is also occluded.
Saphenous vein aortocoronary bypass surgery is frequently performed, and the results have been encouraging in relation to relief of angina and reduction in mortality. Vein graft occlusion occurs in about 20 percent of grafts, 1 and this event has been associated with recurrence of angina and a decrease in left ventricular performance. 2 In addition, progression of proximal coronary arterial obstruction to occlusion in grafted vessels has been observed in 24 to 67 percent of cases3-7 and has been associated with recurrence of angina 4,5 although this point has been ~lisputed. 6,7 Concern for the consequences of progression of proximal coronary disease in grafted arteries is appropriate, but relatively little information is available with respect to alteration of left ventricular function in association with proximal occlusion of the parent coronary artery. In this study left ventricular ejection fraction and segmental wall motion were analyzed before and after coronary bypass surgery in a group of patients in whom the status of both the saphenous vein grafts and the native coronary circulation was defined.
January 1977 The American Journal of CARDIOLOGY Volume39
39
vENTRICULAR FUNCTION AFTER CORONARY BYPASS--STEELE ET AL.
Patients
Sixty-two men (average age 52 years, range 29 to 62 years) with coronary artery disease were studied. All underwent aortocoronary bypass with saphenous veins constructed to either the distal right (9 men), distal left anterior descending (13 men) or both coronary arteries (40 men). No patient had obstruction of more than 40 percent of luminal diameter in the main left or circumflex artery or any of the marginal branches. All grafted coronary arteries had obstructions of 60 to 95 percent of luminal diameter. All patients underwent coronary bypass surgery for the relief of angina. Postoperative cardiac catheterization was undertaken in all cases to evaluate the results of operation, and in some cases because of postoperative myocardial infarction or recurrence of angina. The postoperative study was performed 4 to 27 months (average 11 months) after the bypass procedure.
the long axis of the end-systolic silhouette was quadrisected to form eight chords, four reflecting wall motion of the anterior and four of the inferior wall of the left ventricle (Fig. 1). The percent shortening of each chord was determined and the sum of chords I to 4 that reflected movement of the anterior wall was computed. The sum of the percent shortening of chords 5 to 8 reflected movement of the inferior wall. The long a x i s used for wall motion analysis was also used to calculate ejection fraction and the same cardiac cycle was used for both calculations. The heart rate recorded during the preoperative cineventriculogram was within 20 percent of the rate recorded during postoperative ventriculography. N o r m a l v a l u e s : In 21 normal men (with normal coronary arteriograms) left ventricular ejection fraction averaged 0.66 (range 0.57 to 0.77 [4-2 standard deviations]). Wall motion analysis yielded values for shortening (4-2 standard deviations) along the eight chords of:
Methods
Chord Chord Chord Chord
Cardiac catheterization was undertaken with patients in the postabsorptive state with either no or mild sedation (diazepam 10 to 15 mg orally, and diphenhydramine hydrochloride, 25 to 50 mg orally) and with use of the percutaneous femoral arterial or brachial arterial cut-down approach. Left ventricular cineangiograms were filmed at 60 frames/sec in the 30 to 40 ° right anterior oblique projection after power injection of 32 to 40 ml of 76 percent meglumine and sodium z diatriazoates 76 percent (Renografin®-76, Squibb) over 4 seconds. Either a no. 8F pigtail or a no. 7F National Institutes of Health (Cordis) catheter was used for the ventriculogram. Selective coronary and vein graft injections of contrast medium in multiple projections were performed with either preformed femoral-coronary, brachial-coronary or Sones catheters. Left ventricular ejection fraction (LVEF) was calculated from the left ventricular end-diastolic volume (LVEDV) and the ventriculographic stroke volume (SV) as: SV LVEF - - (1) LVEDV where stroke volume was computed as the difference between left ventricular end-diastolic and end-systolic volumes. Left ventricular volumes were computed from the projected end-diastolic and end-systolic areas (A) and the long axis (aortic valve to left ventricular apex) (L) s,9 as: LVEDV = ~/6 LM 2
1--55 3--54 5--55 7--40
4- 25%; Chord 2--57 4- 24% 4- 27%; Chord 4--59 4- 30% 4- 20%; Chord 6 46 4- 19% 4- 11%; Chord 8--28 4- 26%
These data agree with values observed in normal subjects by Leighton et al. ]° Means of the various groups were compared with Student's paired t test. Results
T h e 62 men had 102 s a p h e n o u s vein grafts constructed to either the distal left anterior descending (53 grafts) or the distal right c o r o n a r y a r t e r y (49 grafts). F o r t y men h a d b o t h arteries grafted. T h u s , 102 segm e n t s (53 anterior, 49 inferior) in these 62 m e n were analyzed, and ejection fraction was determined for each of the 62 men. Segmental wall m o t i o n was n o r m a l preoperatively in 43 segments and abnormal in 59. Ejection fraction was n o r m a l before c o r o n a r y bypass surgery in
(2)
where M is the minor axis, calculated from the area and the long axis as: M = 4_A_A ~L
(3)
Cardiac cycles selected for analysis included only those within the first four occurring after injection, of contrast medium. Beats following premature beats were avoided. Calculations were performed with the assistance of an X-Y digitizer and a digital computer. Left ventricular segmental wall motion was measured using the method of Leighton et al. 1° The projected silhouette at end-diastole in the right anterior oblique view was drawn and a long axis constructed from the apex to a point on theaortic valve so that the two areas of the bisected left ventricle obtained with planimetry agreed within 1 cm2 of each other. The end-systolic silhouette was drawn and a long axis constructed from the aortic valve to the apex using the same point on the aortic valve as used for the end-diastolic long axis. The long axes were superimposed (to correct for systolic rotation) and
40
January 1977
The American Journal of CARDIOLOGY
'\
/
Segmental = OE-ES wall motion OE-L
N/\
x 100
FIGURE 1. Representative normal left ventricular silhouettes (right anterior oblique) at end-systole and end-diastole with the eight chords defining segmental contraction (method of Leighton et al.l°). Percent shortening of chord 4 was computed as the distance from the onset of ejection (OE) to end-systole (ES) divided by the distance from the onset of ejection to the long axis (L).
Volume 39
VENTRICULAR FUNCTION AFTER CORONARY BYPASS--STEELE ET
TABLE I
T A B L E II
Effect of Occlusion of the Parent Coronary Artery on Segmental Wall Motion in 62 Men
Effect of Occlusion of the Parent Coronary Artery on Ejection Fraction
Men-
Ventricular Left-Ventricular Ejection Fraction Seg- (average +- standard error of the mean)
Postoperative Left Ventricular Segmental Wall Motion (compared with preoperative value)
tricular Unchanged Segments no. % (no.)
Worse no.
%
ments
Improved no. %
(no.) Preoperative Postoperative
34
31
91
0
0
33
22
67
6
18
21
6
29
15
71
0
0
14
4
29
10 71
0
0
102
63
62
31
8
8
30
3 9 5
15
P Value
All grafts open,
10
0.55 + 0.03
0.53 + 0.04
NS
All grafts open, all arteries closed* All grafts closed, all arteries open* All grafts closed, all arteries closed*
11
0.51 + 0.02
0.54 + 0.03
NS
8
0.56 + 0.02
0.41 + 0.02
P
