Carotid Artery Endarterectomy in Patients Over Seventy Years-of-Age Herman Schr6e, MD, Raf Suy, MD, Andr6 Nevelsteen, MD, Leuven, Belgium

Carotid artery endarterectomy in the elderly patient has been considered to be a high risk procedure. Recent reevaluation, however, showed that advanced age alone doesn't seem to increase the perioperative surgical risk. We retrospectively reviewed the records for 222 carotid artery endarterectomies, not combined with any other type of surgery, in 195 patients over 70 years-of-age. Twenty-eight patients (14.3%) were asymptomatic, 43% were seen after transient ischemic attacks, 5.1% after reversible ischemic neurologic defects, and 37.4% after stroke. A standard operative protocol was followed. We used a shunt in 45.5% of patients, a standard endarterectomy was performed in 93% of patients, using a patch in 68%. There were three perioperative deaths and seven perioperative strokes in the series; total combined morbidity and mortality was 5.1%. In the 73 patients operated after previous stroke, three died and five suffered a perioperative stroke; total combined morbidity and mortality was 10.9%. In the 122 patients operated after previous transient ischemic attack or asymptomatic, two suffered a perioperative stroke; total combined morbidity and mortality was 1.6%. Late survival was identical to the survival of a normal Belgian control population, and stroke and death-free ratio at five years was 65%, 52% for patients operated after previous stroke and 69% for asymptomatic patients or patients operated after transient ischemic attack. Carotid artery endarterectomy can be performed in patients over 70 years-of-age with perioperative results equal to those of younger patients. (Ann Vasc Surg 1990;4:133-137). KEY WORDS: Carotid artery endarterectomy; carotid endarterectomy in the elderly; stroke; transient ischemic.

One of the most significant demographic facts confronting Western society today is the aging of its population. With the graying of the population comes a greater susceptibility to chronic disease conditions, among which are stroke and strokerelated problems. Stroke, presently the third leading cause of death and the second leading cause of

From the Department of Vascular Surgery., U.Z. Gasthusiberg, Leuven, Belgium. Presented at the Fourth Annual Meeting of the Soci~t( de Chirurgie VascuIaire de Langue Franqaise, June 23-24, 1989, Strasbourg, France. Reprint requests: R. Suy, MD, U.Z. Gasthvisberg, Herestraat 49, 3000 Leuven, Belgium.

cardiovascular death in the USA [1] comes with a very high cost. Several reports mention increased risk for elderly patients undergoing abdominal, thoracic, vascular and cardiac operations [2-5]. The risk classification system devised by Sundt and colleagues [6] shows that patients with arteriographic complicating factors, severe concurrent medical disease (including age), or a fluctuating neurological course are at higher risk when undergoing carotid surgery. Recent reports about carotid artery endarterectomy (CEA) for symptomatic and asymptomatic patients, however, state that advanced age alone doesn't seem to increase the perioperative surgical risk [5,7,8]. If surgical therapy is to offer any distinct 133

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CAROTID E N D A R T E R E C T O M Y I N PATIENTS OVER S E V E N T Y

advantage over medical therapy, the combined mortality and morbidity for carotid surgery should be low [9-11]. We did a retrospective analysis in our institution of all symptomatic and asymptomatic patients over 70 years-of-age undergoing CEA not combined with any other type of surgery.

TABLE I.mTypes and numbers of risk factors Numbers of combined risk factors (%)

Risk factors (%) Coronary atheromosclerosis Hypertension Peripheral vascular disease Diabetes Cancer

42

One risk factor

41

52 28

Two risk factors Three risk factors

31 10

12 6

Four risk factors No risk factors

2 16

PATIENTS AND METHODS Between 1978 and 1988 CEAs were performed in 678 patients in our institution. Of these 222 were in patients over 70 years-of-age, excluding all patients undergoing CAE in combination with any other type of surgery and all patients with progressive stroke. We operated on 195 patients over 70 yearsof-age. Twenty-seven of these patients underwent bilateral CAE. The mean age of this patient group was 74 years (70-84 years). The male to female ratio was 1.9 to 1. Concurrent medical risk factors were high in this population (Table I). Coronary atheroma were documented in 42% of patients, hypertension in 52%, peripheral vascular disease in 28%, diabetes in 12%, and cancer in 6%. Only 16% of patients had no concurrent risk factors, 49% had one, 31% had two, 12% had three or four concurrent risk factors. Patients were selected preoperatively. Angina at rest, cardiac instability, therapy-resistant hypertension, uncontrolled diabetes, and terminal cancer were contraindications for operation. All patients had a preoperative as well as postoperative neurological examination by a neurologist, independent from our surgical unit. On preoperative examination (Table II), 14.3% of patients were asymptomatic, 43% presented after transient ischemic attack (TIA), 5.1% after reversible ischemic neurological defect, and 37.4% after stroke. When evaluating the symptoms related to the operated carotid artery, 47% of patients were asymptomatic, 29% presented after carotid-related TIA, 3% after carotid-related reversible ischemic neurologic defect, and 21% after carotid-related stroke (Table II). Diagnostic evaluation included arteriography, brain computed tomographic (CT) scan and, since 1983, noninvasive imaging studies in all patients. All patients had their operation performed with surgeons using relatively standard techniques. Electroencephalographic (EEG) monitoring was used in every patient, and the operations were performed under general anesthesia using etomidate and isoflurane. In the last two years an infusion of naftidrofuryloxalate was administered perioperatively as well. Hypertension up to 160 mm Hg systolic was commonly instituted. Systemic heparin was given in all cases with a mean dose of 7500 units. In every patient stump pressure measurement was performed. If stump pressure dropped below 50

mm Hg or significant EEG changes occurred, a shunt was inserted. We used a shunt in 45.5% of our patients. A standard endarterectomy was performed in 93% of patients, and we used a patch in 68%. A bypass was performed in 15 patients (7%). Postoperative evaluations included neurological examination by an independent neurologist, brain CT scan and again, since 1983, noninvasive studies of the operated carotid. These noninvasive studies were performed six months postoperatively, and yearly thereafter in 66% of our patients.

TABLE II.--Patient and carotid symptoms

Neurologic symptoms (%)

Symptoms from operated carotid (%)

14.3

47

43.0 5.1 37.4

29 3 21

Asymptomatic TIA short long Stroke

RESULTS Radiologic evaluation and noninvasive studies are presented in Table III. Perioperative results are presented in Table IV. In the entire series of 222 CEAs in 195 patients, 19 patients suffered a neuro-

TABLE III.mCarotid lesion evaluations by

noninvasive studies

Carotid lesion

Percent of patients

Unilateral ICA* stenosis 50-80% diameter reduction 81-99% diameter reduction Bilateral ICA stenosis 50-80% diameter reduction 81-99% diameter reduction 50-99% diameter reduction Contralateral ICA occlusion 50-80% diameter reduction 81-99% diameter reduction

55.0 7.4 47.6 28.4 2.7 13.4 12.3 t6.6 1.6 15.0

*ICA -

Internal carotid

artery

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TABLE IV.--Perioperative complications

100

Neurologic events Fatal sroke (2) Nonfatal stroke (7) Total regression neurologic deficit (4) Mild neurologic deficit (1) Moderate to severe neurologic deficit (2) T1A (10) Cardiac events Myocardial infarction (3) Fatal (1) Nonfatal (2) Total combined morbidity and mortality (5.1%)

80

6o 40 o •

20

logic event, 17 being unilateral. The total combined mortality and morbidity in our series was 5.1%. We divided our 195 patients into two groups: Group A: 73 patients who were operated upon after a previous stroke. Group B: 122 patients who were operated upon after previous TIA or who were asymptomatic. Mean age and risk factors in both these groups were identified, but their perioperative results differed significantly. Seven patients suffered a perioperative stroke after previous stroke; three patients in this group died, one after perioperative myocardial infarction, two from perioperative stroke. The total combined morbidity and mortality in these patients was I0.9%. In the asymptomatic patients or patients who had suffered TIAs, only two suffered a postoperative stroke, and there were no perioperative deaths, bringing the total combined morbidity and mortality down to 1.6%. Late results

All 192 patients were available for follow-up. Their survival was identical to the survival of a normal Belgian control group with the same age and sex distribution [12] (Fig. 1). Their five year survival was 71%. Deaths were due to myocardial infarction in 47.6%, cancer 28.6%, old age 7.1%, stroke 0.5% (1/192), and miscellaneous causes in 16.1%. There were no late T I A s and four late strokes (Fig. 2): one fatal nonrelated stroke; two nonfatal, related strokes; and one nonfatal, nonrelated stroke, Referring again to Groups A and B, late results for both groups differed significantly. In Group A, five-year survival was 60%, and there were three late strokes (4.3% = 3/70), one fatal nonrelated, and two nonfatal related. In Group B, five-year survival was 79% and there was one late nonrelated stroke (0.8% = 1/122) (Figs. 2,3). The stroke and death-free ratio of the total group was 65% at five years. For Group A it was 52%, for Group B 69%, this difference being statistically significant (log rank test, P < 0.01) (Fig. 4).

Belg. pop. pafienfs

_+SE I

I

I

12

I

24

I

I

I

1

I

36 /+8 monfhs

I

I

60

I

I

72

I

84

Fig. 1. Survival of total group, including control group.

DISCUSSION Surgical mortality and morbidity in elderly patients doesn't seem to be exclusively age-related [13], it is also associated with the physical status of these elderly patients [14], the type and urgency of operation performed [2,3,5,15], and the presence of cardiovascular and other concurrent risk factors [16]. In Sundt's study [6] of the perioperative risk of carotid endarterectomy, patients at an age over 70 years carry a perioperative combined risk of 7% regardless of other risk factors. Three recent studies, however, showed that there

10 0 90 ,--

80

.4-c ~ "'

70 rl Sfr. free • Ev. free

60 - _+SE

50

I

0

I

12

I

I

24

! ,,I

36

I

I

/+8

I

|

1

60

months

Fig. 2. Stroke-free and event-free results.

1

72

!

i

84

C A R O T I D E N D A R T E R E C T O M Y I N P A T I E N T S OVER S E V E N T Y

136

100 80

6o . m

~> ¢_

"-1

/,0 group A

o

20

• group B _*SE I

I

I

I

12

24

I

I

I

I

I

I

36 48 monfhs

I 72

60

Fig. 3. Survival for Groups A and B.

was no increased risk for elderly patients undergoing CEA over that for the general population [7,8,13]. Possible explanations are the fact that CEA is considered as minor surgical trauma: patients suffer very little postoperative pain, have lower postoperative pulmonary complications, and are not exposed to infection and sepsis, which cause a high postoperative morbidity and mortality in geriatric patients [2,5,13,15]. The two major complications of carotid surgery continue to be neurologic and cardiac. Neurologic impairment remains the primary complication of carotid artery surgery. This could be due to intracranial occlusive disease. Rosenthal [17]

80

6O QJ I

40-

0

L..

group A • group B

n

20±SE =

0

l

12

i

I

2/,

I

I

I

36 /.8 monfhs

I

I

I

60

Fig. 4. Stroke-free survival for Groups A and B.

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ANNALS OF VASCULAR SURGERY

finds flow-limiting stenotic (> 75%), intracranial, occlusive disease in the siphon or circle of Willis in nearly 50% of an octogenarian population with carotid artery disease, nearly five times the frequency of a younger population with carotid artery disease. We did perform preoperative arteriography (mostly intraarterial, sometimes intravenous) and noninvasive studies in all patients. We only performed a selective intracranial arteriogram when the patient's symptoms didn't seem to correlate with the findings on carotid arteriography, because selective intracranial arteriography isn't without risk. A total complication rate between 2.6% [18] and 1.4% [19] were reported. There is a tendency toward increased risk for neurologic complications in patients with cerebrovascular disease. In our patients below 70 years-of-age we found an equal number of postoperative complications in comparison to the patients over 70 years-of-age. The total combined morbidity and mortality after CEA in patients over 70 years-of-age was 5.1% in our institution. The perioperative mortality rate was 1.5%, and the perioperative stroke rate, 4.6%. In our 483 patients below 70 years-of-age, undergoing CEA, total combined morbidity and mortality was 4.55%, the perioperative mortality 1.65%, and the perioperative stroke rate 4.1%. There was no statistical difference in mortality and morbidity between the patients below and the patients above 70 years-of-age undergoing CEA. When comparing all patients undergoing CEA between 1978-1984 and 1985-1988, for an equal number of operations performed and an equal number of perioperative strokes, we had six fatal strokes between 1978 and 1984 and only two between 1985 and 1988. As our experience grew, we saw fewer severe neurologic complications. Our late results are excellent. Five year survival was the same as the normal Belgian population with the same age and sex distribution. This can be explained by the fact that patients were selected preoperatively. The stroke-free ratio at five years, including early postoperative stroke, was 90%. We saw four late strokes in 192 patients, with one nonrelated, fatal thrombosis of the basilar artery. This is comparable to a stroke-free ratio of 87% in the octogenarian patient group of Rosenthal [17]. In his control population the stroke-free interval was only 67%; it is difficult to evaluate why he didn't operate on the patients in his control group. When we divided our patient population into Groups A and B, there was a significant difference between the results of the two groups. In Group A, total combined morbidity and mortality was I0.9%, perioperative mortality rate 4.3%, and perioperative stroke rate 9.6%. In Group B, total combined morbidity and mortality was 1.6%, there was no

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CAROTID ENDARTERECTOMY IN PATIENTS OVER SEVENTY

perioperative mortality, and perioperative stroke rate was 1.6%. Our results for post-TIA and asymptomatic patients are excellent with total combined morbidity and mortality of 1.6%, which is well below the generally accepted rate [5,9,20,21]. There are several explanations for the difference between Groups A and B. Whether or not postreversible ischemic neurologic defects or poststroke patients have a persisting zone of ischemic brain tissue surrounding an old infarct remains to be proved [20,22,23]. The obligatory use of an indwelling shunt in postreversible ischemic neurologic defects and poststroke patients remains a point of discussion when reviewing the international literature [13,20,22,23]. Technical errors that caused carotid artery thrombosis could account for most of the neurologic deficits after CEA [20]. Five of a total of nine postoperative strokes were caused by a thrombosis of the operated carotid artery. Four thrombectomies were performed; three of these patients made a full recovery from their stroke. Late survival, as well as late stroke rate, differ for patients in Groups A and B, although mean age and risk factors are identical for both groups. This seems to indicate that postreversible ischemic neurologic defects of poststroke patients are more susceptible to cardiovascular complications than post-TIA or asymptomatic patients, although risk factors are equally distributed.

CONCLUSIONS Carotid artery endarterectomy in patients over 70 years-of-age has achieved the same clinical results as CEA in younger patients, in the absence of severe concurrent medical disease. Carotid artery endarterectomy is recommended in elderly patients before the onset of stroke as most of our complications occurred in patients operated upon after a previous stroke.

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