AUGUST

The American

Journal

1979

of CARDIOLOGY@ VOLUME

NUMBER

44

2

CLINICAL STUDIES

Atherosclerosis of the Left Main Coronary Artery: 5 Year Results of Surgical Treatment FLOYD

D. LOOP,

BRUCE

W.

DELOS

M. COSGROVE,

WILLIAM MANUEL PAUL

LYTLE,

MD,

C. SHELDON, IRARRAZAVAL,

C. TAYLOR,

FACC

MD MD MD, FACC MD

MD

LAWRENCE K. GROVES AUGUST0 D. PICHARD,

MD*

Cleveland, Ohio

From the Department of Thoracic and Cardiovascular Surgery and the Department of Cardiology, The Cleveland Clinic Foundation, Cleveland, Ohio. Manuscript received January 11, 1979; revised manuscript received March 5, 1979, accepted March 7, 1979. Present address: Mount Sinai Hospital, Division of Cardiology, New York, New York. Address for reprints: Floyd D. Loop, MD, Department of Thoracic and Cardiovascular Surgery, The Cleveland Clinic Foundation, 9500 Euclid Avenue, Cleveland, Ohio 44106. l

Three hundred consecutive patients received coronary arterial bypass grafts as treatment for stenosis of the left main coronary artery. Ostlal stenosis was more prevalent among women (P 15 mm Hg

163

43

77

46

31

13

8

5 2

30;:

21: (73%)

206 (667%)

(2z&)

-2 1

z 28 30:

12 (4%)

IMA = internal mammary artery.

revascularization, 3 died intraoperatively or postoperatively. Thirteen of these 15 emergency procedures were performed less than 24 hours after cardiac catheterization. Twelve of the surviving patients (4 percent) had perioperative myocardial infarction manifested by elevated cardiac enzyme values and new Q waves in the electrocardiogram. Including operative deaths caused by infarction, 23 patients (7.7 percent) experienced perioperative myocardial damage. Graft patency: Postoperative coronary cinearteriography was performed in 148 (51.4 percent) of the 288 surviving patients at an interval that ranged from 1 week to 72 months, (mean 16.5 months). Table III records the patency rate of veins or arterial grafts constructed to each of the major coronary vessels. Of 337 grafts studied, 298 (88.4 percent) were patent. Thirtysix of these were internal mammary artery grafts, all of which were widely open. Ten of the 16 patients who had undergone right coronary endarterectomy were restudied, and all of the grafts performed in conjunction with endarterectomy were patent. Of 148 patients who underwent a single postoperative catheterization, 141 (95.3 percent) had at least one patent graft. Thirteen patients had two catheterizations postoperatively, and two had three postoperative catheterizations after a mean interval of 43 months. Of 27 vein grafts open initially, 26 were patent later and three internal mammary artery grafts studied a second time remained patent. One circumflex graft stenotic proximally at 11 months became occluded. Second angiograms disclosed new lesions estimated at 50 and 20 percent, respectively, in vein grafts to a right coronary artery and a diagonal branch. Late mortality: Complete follow-up information was obtained. The survivors were reached by telephone; when there was a history of a postoperative cardiac event or an interim hospitalization, the physician was contacted to document the occurrence. Follow-up periods ranged from 49 to 110 months with a mean follow-up interval of 69 months. There were 260 late survivors; of these, 184 (70.8 percent) were followed up 60 months or longer. Twenty-eight patients died in the late period after initial hospital discharge. Causes of late mortality included sudden death (within 1 hour of collapse) in 10 patients, documented myocardial infarction

in 6 patients, congestive heart failure in 3 patients and noncardiac factors in 9 patients. For those whose cause of death was not considered cardiac, the attributable causes were cancer, (three patients), alcoholic cirrhosis (two patients), hepatitis (one patient), diabetic acidosis (one patient), suicide (one patient) and stroke (one patient). Actuarial survival of the entire 300 patients calculated to 5 and 6 years was 88.2 and 87.1 percent, respectively. Data on early and late mortality, survival at the point of follow-up (mean interval 69 months) and 5 year actuarial survival for subgroups categorized by the extent of disease are shown in Table IV. There were no significant differences in 5 year actuarial survival among the subgroups. Combining the subgroups of patients with right coronary artery disease (narrowing greater than 60 percent) yielded an 85.2 percent 5 year actuarial survival rate as opposed to 89.3 percent for those without right coronary arterial stenosis (difference not significant). The actuarial survival at 5 years for patients with critical stenoses of the right coronary artery, circumflex coronary artery and left anterior descending coronary artery as well as the left main coronary artery was 84.2 percent at 5 years, a figure not

TABLE III Postoperative Vein and Internal Mammary Artery Grafl Patency RCA

LAD

cx

DG

120

9

Total

Vein Grafts Studied (no.) Occluded (no.) Patent (no.) Total (%)

64 :; 82.8

306 8

1:; 84.2

K.5

: 100

299 2:: 57.3

IMA Grafts l

Studied (no.) Occluded (no.) Patent (no.) Total (% )

0

31 0 1::

: 1 100

: to:

36 0 1::

DG = diagonal branch; IMA = internal mammary artery; LAD = left anterior descending coronary artery; LCx = left circumflex artery; RCA = right coronary artery.

August 1979

The American Journal of CARDIOLOGY

Volume 44

197

ATHEROSCLEROSIS OF LEFT MAIN CORONARY ARTERY-LOOP

ET AL.

TABLE IV Survival in Subsets of Patients With Stenosis of the Left Main Coronary Artery Operative Deaths (no.)

Patients (no.) 38 9 33

LMCA only LMCA + LCx LMCA + LAD LMCA + LCx + LAD LMCA + RCA LMCA + LCx + RCA LMCA + LAD + RCA LMCA + LAD + RCA + LCX Total LMCA series

Early Mortality (%)

Late Deaths (no.)

7.9 0 2:;

1 :

;1 1:‘:

: 3

7.7 4.5 2.1 3.0

300

12

4.0

5 ; 1 14

28

Late Mortality (“/)

Survival and Follow-up+

5 Year Survival

23.8 3.0 12.5 4.8 8.5 14.3

92.1 100.0 72.7 94.1 80.8 90.9 89.6 83.2

92.1 100.0 81.8 97.1 83.3 90.9 91.6 84.2

9.7

86.7

88.2

l

(“/)

Late mortality = no. of late deaths/no. of surgical survivors. + Mean follow-up: 69.4 months. LAD = left anterior descending coronary artery; LCx = left circumflex coronary artery; LMCA = left main coronary artery; RCA = right coronary artery. l

significantly different from the actuarial survival rate of other subsets. Figure 1 shows the actuarial survival curves for patients with isolated stenosis of the left main coronary artery, patients with left main stenosis plus anterior descending or left circumflex stenosis, or both, and patients with left main stenosis plus right coronary arterial stenosis. Correlation of survival with other clinical features: Revascularization was defined as complete when all major vessels (including diagonal and circumflex marginal branches) with estimated narrowing of 60

..----., I

100

“X,_,

95

~~~-~.______.__----.,,

i\

.-.-.--_.--11+..

._._.2~._..._.-.-. +.

-.Ql.

~.I ..,..\.

‘\. .

‘.__

“, ... . ,_,

“...* ............. ........

z 80

7% I”

J 0

-.-.----

ISOLATED LMCA n=38 LMCA + LAD +/or CX n=65

-

ALL PTS WITH LMCA AND RCA STENOSIS n= 197

.............. LMCA + LAD + CX + RCA n= 101

I I

I 2

I 3

I 4

1 5

percent or greater received bypass grafts. For 143 patients with complete revascularization the 5 year survival rate was 89.3 percent versus 87.1 percent for patients with incomplete revascularization (difference not significant). When survival was correlated with preoperative left ventricular contraction, 90.3 percent of those with

normal contraction survived 5 years compared with an 83.4 percent survival rate for those with estimated abnormal contraction (P