Original articles

The Evolution of Carotid and Coronary Artery Disease After Operation for Carotid Stenosis Jean-Baptiste Ricco, MD, Jean-Baptiste Gauthier, MD, Jean-Pierre Richer, MD, Philippe Benand, MD, Marie-H61~ne Bouin-Pinaud, MD, Bernard Demiot, MD, Helyett Auguy, MD, Jacques Barbier, MD, Poitiers, France

We followed 278 consecutive patients undergoing carotid artery surgery between January 1985 and December 1989 using a computerized surveillance program file with automatic carotid and coronary artery follow-up investigations every six months. Combined postoperative neurologic mortality and morbidity was 1.7%. During the mean follow-up period of 30 months, 10 patients died, four due to myocardial infarction. Actuarial rates of survival and freedom from cerebral vascular accidents at 36 months were 94% and 95.8%, respectively. No fatalities due to cerebral vascular accidents occurred during follow-up. Eleven patients had myocardial infarction, an actuarial rate of 6% at 36 months; 18 patients experienced angina pectoris, while seven sustained silent electrical myocardial ischemia. Findings on myocardial angioscintiscans and coronary artery arteriograms led to four aortocoronary bypasses and seven percutaneous coronary artery dilatations. Duplex scanning documented three asymptomatic carotid restenoses of -> 80%, which were operated upon, and 32 contralateral carotid artery stenoses ranging between 80% and 99%, 24 of which were asymptomatic. Twenty-eight patients underwent secondary contralateral carotid artery revascularization. No one with contralateral carotid artery stenosis < 80% experienced a carotid artery ischemic event. These results clearly show the value of cardiac and neurologic surveillance of patients operated on for carotid artery stenosis. (Ann Vasc Surg 1992;6:408--412). KEY WORDS: Carotid artery stenosis; carotid endarterectomy; coronary artery disease; neurologic complications; computerized surveillance programs; myocardial infarction.

According to Hertzer and Arison [1], 27.4% of patients who undergo carotid artery endarterectomy will die of myocardial infarction (MI) and 12.5% of a cerebral vascular accident (CVA) within From the Service de Chirurgie Visc~rale et Vasculaire and the Service d'Explorations Vasculaires, Centre Hospitalier Regional et Universitaire, Poitiers, France. Presented at the Annual Meeting of the SociPtO de Chirurgie Vasculaire de Langue Franfaise, May 18-19, 1990, Nancy, France. Reprint requests: J-B Ricco, MD, Service de Chirargie Visc~rale et Vasculaire, H@ital Jean Bernard, 86021 Poitiers, France.

10 years after operation. The actuarial CVA rate in these patients is 26.3% at 10 years [1] and most of these are due to progression of contralateral carotid artery disease. Complications of coronary artery disease are therefore the principal cause of mortality in patients undergoing carotid artery endarterectomy, and most of the late postoperative neurologic complications in this setting are due to progression of lesions in the contralateral carotid artery. Based on the outcome and the results of a regular follow-up program for patients operated upon for carotid artery disease during these last five years, the objectives of this study were to determine:

408

VOLUME 6 N o 5 - 1992

E V O L U T I O N OF CAROTID A N D C O R O N A R Y DISEASE

I) the incidence and the severity of coronary artery complications; 2) the natural history of the operated and contralateral carotid arteries; and 3) the efficacy of regular cardiac and carotid artery duplex scanning surveillance in this setting.

PATIENTS AND METHODS Between January 1985 and December 1989, 278 consecutive patients underwent a carotid revascularization procedure. There were 232 men (83%) and 46 women (17%) whose mean age was 67.3 -+ 9.3 years. A transient ischemic attack (TIA) led to the discovery of carotid artery disease in 180 patients (65%), while 38 (13%) patients had experienced a partially reversible hemispheric eVA. Sixty patients (22%) were asymptomatic and carotid artery disease was disclosed during work-up for peripheral artery occlusive disease. The mean follow-up period for these patients was 30 months. Assessment of coronary artery disease

The surveillance program included history taking, clinical examination, and resting and exertional electrocardiograms performed by the patient's cardiologist. Beginning in 1988, myocardial thallium scintiscans with dipyridamole potentialization were obtained whenever clinical symptoms (progressive angina, residual angina following infarction) or electrical manifestations (repolarization disorders with depressed ST segment or negative T waves) were observed.

409

TABLE I.nActuarial survival of patients undergoing carotid endarterectomy Lost to follow- Actuarial up rate* Months Patients Deaths Excluded 0--6 7-12 13-18 19-24 25-36

278 247 222 188 145

3 1 2 2 2

25 22 32 39 97

3 2 0 2 7

98.9 98.4 97.5 96.3 94

(1.2) (1.5) (1.9) (2.5) (4.1)

*Actuarial survival corresponding to percentage of surviving patients; 95% confidence intervals are given between parentheses.

were calculated with this data bank. Actuarial curves were compared using the log rank test. RESULTS Hospital mortality and morbidity

Three patients died, all of MI (1%) while two patients experienced a nonfatal e V A due to occlusion of the operated carotid artery (0.7%), i.e. a combined postoperative mortality and morbidity rate of 1.7%. Late deaths

Fourteen patients (5%) were lost to follow-up. Actuarial survival at 36 months was 94 -+ 4.1% (Table I). Ten patients died, four of MI. All four patients were less than 55 years old. None of the other patients died of fatal e V A during the follow-up period.

Carotid artery assessment

At each visit, duplex scanning of both carotid and vertebral arteries was performed. The initial examination was carried out immediately postoperatively, then every six months during the first three years, and every year thereafter. All patients were followed by a software program which automatically generated prescriptions for cardiologic and vascular investigations. Actuarial rates of survival as well as cardiologic and neurologic events

Coronary artery events

Thirty-six patients (11%) experienced a coronary artery event (11%). Eleven patients sustained MI (Table II) for a 36 month actuarial rate of MI of 6 -+ 3.3%. Eighteen patients had clinical manifestations associated with coronary artery insufficiency while seven patients had asymptomatic myocardial ischemia disclosed by electrocardiographic recordings. Coronary artery involvement was confirmed in these 25 patients

TABLE II.--Actuarial study of occurrence of myocardial infarction in patients undergoing carotid endarterectomy

Months 0-6 7-12 13-18 19-24 25-36

Patients

Infarction

Excluded

Lost to follow-up

278 247 222 188 145

2 2 2 4 1

26 21 32 37 99

3 2 0 2 7

Actuarial diseasefree rate* 99.2 98.4 97,4 95 94

(1.1) (1.5) (2.1) (3.1) (3.3)

*Actuarial disease-free rate corresponding to percentage of patients without myocardial infarction; 95% confidence interval is given between parentheses.

410

Clinical

N=

ANNALS OF VASCULAR SURGERY

EVOLUTION OF CAROTID AND CORONARY DISEASE

111

C~

No

140,)

~

~

clinical

N=

C~

167 (60~)

TABLE III.--Actuarial rate of occurrence of cerebral vascular accidents in patients undergoing carotid endarterectomy

Carotid surgery N

=

278

I Postoperative mortality due to CAD N = 3 (1%)

r

Coronary events N

:

36

=

11

N

\

=

7

// Angina N : 18

\

I

\~ /J

/

/J

,/

Coronary angiography "-

//

Percutannous angioplasty N = 7

0-6 7-12 13-18 19-24 25-36

99,2 98.8 97,8 96.7 95.8

278 245 220 185 142

2 1 2 2 1

28 22 33 39 100

3 2 0 2 7

(1.1) (1.3) (1.9) (2.5) (2.9)

Electric ischemia

(4 d e a t h s )

,.

Actuarial diseasefree rate*

CVA= cerebral vascular accidents *Actuarial disease-free rate corresponding to percentage of patients without CVA; 95% confidence interval is given between parentheses.

111%1

Myocardial infarction N

Lost to followMonths Patients CVA Excluded up

Coronary bypass N= 4

Fig. 1. Coronary outcome in 278 patients undergoing carotid endarterectomy between January 1985 and December 1989.

by myocardial angioscans and detailed by coronary arteriograms. Eleven patients had significant coronary artery lesions which were amenable either to percutaneous dilatation (seven patients) or coronary artery bypass (four patients) (Fig. 1). The actuarial rate of coronary artery events (MI, angina pectoris, and asymptomatic electrical ischemia) was 12 -+ 7.2% at 36 months in Ill patients with antecedent coronary artery disease or MI. It was 2-+2% at 36 months in the 167 patients who had never experienced any symptoms of coronary artery disease. This difference was significant (p < 0.05). Neurologic events

The actuarial rate of patients having no neurologic ischemic event was 95.8 -+ 2.9% at 36 months (Table III). Eight patients experienced a CVA, whereas five patients had TIAs. One patient each had a CVA or TIA in the vascular territory of the operated carotid artery. Both of these accidents occurred during MI complicated by cardiac rhythm disorders, and both had had a normal carotid duplex scan. The 11 other neurologic complications (seven CVAs and four TIAs) were due to lesions of the contralateral carotid artery.

Progression of operated lesions

Early postoperative duplex scanning obtained for operated carotid arteries documented two restenoses of more than 50% and two postoperative asymptomatic occlusions (Table IV). Both cases of restenosis occurred in patients for whom the arteriotomy had been closed with saphenous vein angioplasty which was too wide leading to partial thrombosis at the site of the carotid patch. One of these patients experienced transient amaurosis fugax. Both of these patients underwent reoperation and had a narrow polytetrafluoroethylene (PTFE) patch followed by an uneventful recovery. The two asymptomatic occlusions occurred in patients whose carotid arteriotomy had been closed by direct suture. One-hundred and sixteen patients were followed for at least 18 months and underwent duplex scanning (Table V). Thirteen of these patients (7.4%) had carotid restenosis between 50 and 79% and three (1.7%) had restenosis greater than 80%. Of the I01 patients undergoing patch angioplasty, five (5%) had restenosis of greater than 50%. Of the 75 patients who had direct closure of their carotid arteriotomy, 11 (14.7%) had restenosis of 50 percent or more and of these, three had restenosis of 80% or more. Carotid restenosis occurred significantly more frequently in patients in whom closure was made directly, as compared with patients undergoing patch angioplasty (p < 0.05). The three patients TABLE IV.--Postoperative duplex scanning in

patients undergoing carotid endarterectomy

Stenosis (%) 0-49 50-79 8O-99 100 No follow-up examination Total

Carotids

CEA with patch angioplasty

CEA without patch angioplasty

254 1 1 2 20

142 1 1 0 12

112 0 0 2 8

279

156

122

CEA = carotid endarterectomy

E V O L U T I O N OF CAROTID A N D C O R O N A R Y DISEASE

VOLUME 6 NO 5 - 1992

TABLE V.mFollow-up (18 months) combined duplex scanning in patients undergoing carotid endarterectomy

Stenosis (%) 0-49 50-79 80-99 100 Total CEA =

Carotids

CEA with patch angioplasty

CEA without patch angioplasty

160 13 3 0 176

96 5 0 0 101

64 8 3 0 75

carotid endarterectomy

with restenosis of more than 80% underwent carotid artery reconstruction with vein graft and had an uneventful recovery.

Progression of contralateral lesions

Of 278 operated patients, 36 (13%) had occlusion of their contralateral carotid artery, whereas eight (3%) had contralateral carotid artery stenosis of more than 80%, requiting contralateral carotid reconstruction within one month of the initial operation. Initially, 160 patients (57%) had contralateral carotid artery stenosis of less than 50% while 74 patients (27%) had a 50-80% stenosis of their contralateral carotid artery. Follow-up of the 160 patients with contralateral carotid stenosis, initially less than 50%, showed that 158 (98.7%) remained asymptomatic while stenosis progressed to greater than 80% in two patients (1.3%) and was responsible for CVA (Table VI). Of the 74 patients whose contralaterat carotid stenosis was initially between 50 and 79%, surveillance showed that stenosis increased to greater than 80% in 30 (41%), including one patient who had occlusion.

Neurologic complications related to progression contralateral lesions

of

4t 1

DISCUSSION Carotid endarterectomy undoubtedly decreases the risk of CVA in the operated carotid vascular bed [3,4]. in our experience, only two postoperative neurologic complications occurred (one TIA and one CVA) on the side ipsilateral to operation. These two neurologic complications were apparently unrelated to progression of lesions in the operated carotid artery, but were most likely secondary to cardiac rhythm disorders occurring during the acute phase of MI. Screening for restenosis of the carotid artery is nonetheless a very important element of surveillance. Of the 176 patients followed for t8 months, 16 (9.5%) had restenosis greater than 50%, all of which, however, were asymptomatic. Although carotid artery restenosis seems to be well tolerated and remains asymptomatic for a long time [5], these lesions can progress to occlusion. Restenosis should therefore be detected before occlusion occurs. Of interest in our study was the preventive role of patch angioplasty, since the rate of restenosis was 14.7% when the arteriotomy was closed directly, whereas it was 5% when the arteriotomy was closed by prosthetic or vein patch angioplasty. This is in accordance with Eikelboom and associates [6] who showed in a randomized study that patch angioplasty was associated with less restenosis. One of the essential aspects of operative followup concerns the natural history of the contralateral carotid artery. Patients with contralateral carotid artery stenosis of 80% or greater were operated upon within the month following the initial carotid revascularization procedure. These patients are at a high risk for CVA, which occurred in 12% of patients at five years in the study of Sterpetti and colleagues [7]. Patients who had initial contralateral stenosis between 50% and 80% were followed every six months by duplex scanning. This surveillance was undoubtedly insufficient as stenosis progressed to greater than 80% in 41% of these patients (30/74) and was associated with complications in seven (TIA in four and CVA in three). The severity of this progression contrasts with the natural history of the 158 patients in whom the contralateral stenosis was less than 50%. In this group, the diameter of 156 of the contratateral carotid arteries (98.7%) remained

Eleven of 13 neurologic complications (seven CVAs and four TIAs) occurred in the contralateral carotid territory. Three CVAs occurred in patients who iniTABLE Vl.--Foliow-up (36 months) duplex scanning tially had an occluded carotid artery. The four remain- of contralateral carotid artery in patients undergoing ing CVAs occurred in patients who had contralateral carotid endarterectomy stenosis of more than 80%. Overall, 31 instances of stenosis of 80% or more and one contralateral carotid Initial Carotids Outcome