MJA: Bourke & Crimmins, Overnight hospital stay for carotid endarterectomy

Overnight hospital stay for carotid endarterectomy

Bernard M Bourke and Denis C Crimmins

MJA 1998; 168: 157-160
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Abstract - Introduction - Methods - Results - Discussion - References - Authors' details
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Abstract
Objective: To determine if overnight hospital stay after carotid endarterectomy (CEA) is feasible and safe in the Australian setting.
Design: Case series with follow-up of 4-11 months (mean, 7 months).
Patients and setting: All patients undergoing primary CEA performed by a vascular surgeon (B M B) between 30 May and 11 November 1996. Surgery was performed in one of four hospitals (a district general public hospital with about 400 beds and three private hospitals) in the Gosford area of New South Wales.
Interventions: CEA using regional anaesthesia and sedation, after diagnosis by duplex ultrasound scan, avoiding cerebral angiography and intensive care; planned discharge after overnight hospital stay; review at one month and duplex ultrasound scan at four months.
Outcome measures: Length of hospital stay and complications.
Results: 65 patients were admitted for CEA during the study period and 59 were scheduled for overnight stay (one had "re-do" surgery, two remained longer for reasons unrelated to carotid artery disease, and three had been scheduled before the change to overnight stay). 54 (92%) were discharged on the first postoperative day, and only three required readmission within 30 days (for urinary retention, angina and reperfusion syndrome). There were no deaths, no myocardial infarctions and no recognised instances of cerebral ischaemia during follow-up.
Conclusion: CEA can be performed safely without cerebral angiography or intensive care, with over 90% expectation of a single night's stay in hospital.
Introduction
Carotid endarterectomy, once controversial, has now been established by major prospective trials as highly efficacious in preventing cerebral ischaemic events in patients with carotid artery disease.^1-4 Reflecting this evidence, the annual number of carotid endarterectomies performed in Australia increased from 3384 in the 1991-92 financial year to 5427 in 1994-95.⁵
Nevertheless, use of carotid endarterectomy in asymptomatic patients is still questioned, because of its potential for serious complications⁶ and claims that it is not cost effective.⁷ In addition, the operation is now facing challenges from new procedures -- carotid angioplasty and stenting -- which are claimed to be effective, with shorter hospital stays.⁵
However, studies in the United States have shown that the traditional four- to six-day hospital stay after carotid endarterectomy can be reduced and postoperative intensive care avoided without compromising patient safety.^8-10 Further, recent major advances in non-invasive methods of diagnosing extra cranial carotid disease (eg, duplex ultrasound)^11,12 have raised questions about the need for cerebral angiography (itself carrying about 1% risk of stroke¹³) before surgery. In addition, although general anaesthesia is used for carotid endarterectomy at most Australian centres (with notable exceptions¹⁴), many major overseas centres favour regional cervical or local anaesthesia.^15,16 These have the advantage of allowing the procedure to be performed in patients who are unfit for general anaesthesia.
We tested the hypothesis that carotid endarterectomy can be performed in the Australian setting with reduced resources (avoiding cerebral angiography and intensive care) while maintaining an acceptable standard of care. We report the outcomes for the first 59 patients scheduled for carotid endarterectomy with overnight hospital stay in the practice of the surgical author (B M B).
Methods

Subjects and setting
Subjects were all patients who had primary carotid endarterectomy performed by B M B between 30 May and 11 November 1996. All were scheduled for overnight postoperative hospital stay, unless longer stay was indicated for management of conditions unrelated to carotid artery disease. Surgery was performed in one of three private hospitals or the major district general public hospital in the Gosford area of New South Wales.
Patients had either been referred by general practitioners or other specialists with symptoms of internal carotid artery disease, or signs such as audible cervical bruit, or had been undergoing regular ultrasound monitoring of the internal carotid artery (eg, patients with coronary artery disease or previously treated contralateral coronary disease).
Carotid endarterectomy was offered to:
Patients with typical symptoms of internal carotid artery disease (retinal ischaemia, cerebral hemispheric transient ischaemic attacks or completed stroke) and 60% or greater stenosis at the origin of the appropriate internal carotid artery;

Patients with typical symptoms but less than 60% stenosis, if duplex ultrasound examination showed carotid plaque to be the likely cause of symptoms;

Asymptomatic patients with 80% or greater stenosis; and

Asymptomatic patients with 60%-79% stenosis, if the stenosis had progressed from less than 60% within six months or they specifically requested surgery.
No patients who fulfilled these criteria were considered "medically unfit" for the procedure. All agreed to surgery.
Duplex ultrasound
Stenosis of the internal carotid artery was assessed by duplex ultrasound examination (combination of Doppler and B-mode ultrasound) performed according to internationally recognised standards¹⁷ either by B M B or by one of two fully accredited vascular technologists. Stenosis was graded as none to moderate (< 60%), severe (60%-79%) or critical (80%-99%), according to the haemodynamic parameters of Zwiebel¹⁸ (Box 2, below). As degree of stenosis determined by duplex ultrasound examination may differ from that determined by cerebral angiography, we also applied the more stringent haemodynamic criteria of Carpenter et al¹⁹ to ultrasound results.
The decision to use duplex ultrasound examination routinely instead of cerebral angiography was based on comparison of the results of the two tests and the atheromatous plaque removed at carotid endarterectomy (the "ultimate" gold standard) in about 400 of B M B's previous patients (unpublished data). Since then, duplex ultrasound had been used routinely instead of cerebral angiography for a further 400 patients before the present study.
Surgery

At the preoperative consultation, B M B explained that the patient would be admitted on the day of surgery and discharged on the first postoperative day. The availability of a relative or friend competent to care for the patient was also assessed. Preadmission assessment (full blood count, coagulation screen, estimation of blood urea, creatinine and electrolytes, electrocardiography and chest x-ray) were performed in the week before surgery.
All procedures were performed in conscious patients with regional cervical block and sedation given by the method of Davies et al.¹⁴ After surgery, patients were nursed in the recovery room for four to six hours and then either sent back to a general surgical ward (in the public hospital), or assigned a special nurse in a general or high dependency ward (in the private hospitals).
All patients were reviewed by medical staff twice on the first postoperative day and discharged in the care of a relative or friend that afternoon with instructions to contact the surgeon about any concerns, unless complications requiring further hospitalisation were apparent. The first 12 patients in the series were telephoned by B M B on the second postoperative day, but this practice was discontinued as it was considered unnecessary and alarming for the patient.
Follow-up

All patients were followed up with a consultation with B M B a month after surgery and a duplex ultrasound scan four months after surgery, to assess symptom recurrence and development of disabling stroke or significant surgical or medical complications. Patients continue to be followed up at 6- to 12-month intervals.
An independent clinician (D C C) retrospectively reviewed all patients' hospital records to verify major morbidity (stroke or myocardial infarction), mortality and consecutiveness of the series, usually within a month of patient discharge.

Results

Subjects
Of the 65 patients who had carotid endarterectomy between 30 May and 11 November 1996, 59 were scheduled for overnight postoperative stay. The other six were not scheduled for overnight stay as they were undergoing "re-do" surgery (one patient), had been scheduled before the change to overnight stay and therefore had not been counselled about a short stay (three patients), or needed longer hospital stay for reasons unrelated to carotid artery disease (two patients). One of these asked to remain in hospital for cataract surgery, and the other was taking warfarin and was admitted under the care of a cardiologist four days before surgery, and remained four days after, for stabilisation of this drug. Independent assessment of these patients' records by D C C to verify the reason for exclusion showed that none experienced complications which would have prolonged their stay more than a night had they been entered into the study.

The 59 patients scheduled for overnight stay comprised 38 men and 21 women. Their characteristics are shown in Box 2, and the indications for carotid endarterectomy in Box 3. Forty of the 59 patients had symptoms of carotid artery disease (either typical, such as carotid transient ischaemic attacks, or possible, such as non-hemispheric ischaemia) plus 60% or greater stenosis of the internal carotid artery, according to the criteria of Zwiebel.¹⁸ All but three of these also met the criteria of Carpenter et al¹⁹ for 60% or greater stenosis. Of the five patients with typical symptoms but less than 60% stenosis, duplex scan showed the carotid plaque to be hypoechoic and, in B M B's opinion, the likely cause of the symptoms. At operation in all five, the plaque was found to be soft, friable and ulcerated, supporting this assessment (Figure 1).

All but two of the asymptomatic patients had either a critical (80%-99%) stenosis or a severe (60%-80%) and progressive stenosis (Figure 2). The two exceptions had severe but non-progressive stenosis and requested surgery after the risks and benefits and results of recent trials had been explained to them .
Cerebral angiography was used to confirm duplex ultrasound results in one of the 65 patients, as heavy calcification made imaging less than optimal.
Of the 54 patients with 60% or greater stenosis by the criteria of Zwiebel,¹⁸ all but three also met the criteria of Carpenter et al¹⁹ for this degree of stenosis. Therefore, we were confident that almost all would have fitted the criterion of at least 60% stenosis by angiography as applied in the Asymptomatic Carotid Atherosclerosis⁴ and North American Symptomatic Carotid Endarterectomy¹ trials.
Hospitalisation and surgery
Thirty-six of the operations were performed in a public hospital and 23 in private hospitals. Fifty-three of the 59 patients were admitted on the day of surgery. Another two were already in hospital for investigation of cerebral symptoms under the direction of a neurologist, and four were admitted the previous day (two because of transport difficulties that prevented them reaching hospital early enough on the morning of surgery and two because of administrative errors).
In five operations, the arteriotomy was closed primarily, while in 53 operations (90%) a vein patch was inserted; no synthetic patches were used. The remaining operation was aborted after the skin incision, as the patient had an extreme panic attack. Nine patients (15%) required cerebral protection with a shunt after evidence of intraoperative cerebral ischaemia. Average operation times were: without patch, 77 minutes (range, 65-105 minutes), and with patch, 98 minutes (range, 70-145 minutes). Two patients with angina were sent to the intensive care unit for the first post- operative night.
Outcome measures

Hospital discharge: 54 of the 59 patients were discharged on the first postoperative day (Day 1), and four on Day 2 (two were kept in hospital because of angina and one because of nausea, and one refused to go home on the first day, despite agreeing preoperatively). The remaining patient was not discharged until Day 3 because of prolonged headache.
Complications: Complications are shown in Box 4. There were no deaths or cases of cerebral ischaemia or myocardial infarction. All complications, except the reperfusion syndrome, became apparent within one day of surgery.

The patient with reperfusion syndrome was readmitted with a generalised seizure on Day 5 and required ventilatory support for 13 hours, but made a complete recovery after 24 hours. Cerebral computed tomography showed frontal oedema associated with a small area of possible cerebral haemorrhage, but no evidence of cerebral ischaemia. Clinically, there were no neurological deficits.
Two other patients were readmitted within 30 days, one on Day 3 for urinary retention, which had not been present at discharge, and one on Day 23 for unstable angina. The latter had known inoperable coronary artery disease and had been admitted several times before carotid endarterectomy for angina.
Patient acceptance of overnight stay: Discharge on Day 1 was very well accepted by all but one patient, who had agreed to it preoperatively, but in the event refused to go home until Day 2. Most patients were relieved in that discharge the day after surgery seemed to "defuse" the magnitude of the procedure for them.
Follow-up: All patients were followed up, for an average of 7 months (range, 4 to 11 months). At one-month follow-up, all previously symptomatic patients reported relief of symptoms, including eight who had had non-hemispheric ischaemia. None reported new neurological symptoms, and there were no significant medical or surgical complications (ie, requiring hospitalisation or outpatient treatment). Four-month duplex scanning showed that three patients had evidence of intimal hyperplasia (peak systolic velocity in the internal carotid artery greater than 130 cm/s), and one patient had asymptomatic occlusion of the internal carotid artery. The remaining endarterectomised vessels were widely patent without abnormality.
Discussion
The results of this case series show that carotid endarterectomy can be performed safely with basic resources, avoiding both carotid angiography and intensive care, and with reduced postoperative hospital stay.
Complications in this series compared favourably with those found in previous, major surveys (0-7.5% major complication rate,^1,3,21 depending on the type of patient). No deaths or strokes occurred in our series. The only major complication was one case of reperfusion syndrome. This is a rare event after carotid endarterectomy (incidence, 0.4%), and is thought to be caused by revascularisation of a chronically ischaemic cerebrovascular bed. It may occur up to seven days after operation and may progress to seizures, cerebral haemorrhage and death.²² It is usually preceded by a headache, and, although minor headache is common after carotid endarterectomy, patients with severe headaches should not be discharged.
Importantly, all complications except the reperfusion syndrome became apparent within one day of surgery, supporting the proposal that longer monitoring in hospital is not needed for patients who have shown no signs of complications within this time.
Avoiding cerebral angiography and intensive care and shortening postoperative hospital stay reduces the cost of carotid endarterectomy. In the United States, Ascer et al showed that averting standard angiography and limiting hospital stay to one night saves US$6900 per patient.²³
Avoiding cerebral angiography also reduces costs indirectly; the investigation itself can cause stroke,¹¹ which must be included in the overall cost analysis. According to an NHMRC cost analysis, a stroke costs the community $40 243.⁵
Reducing the cost of carotid endarterectomy could make the procedure more cost effective in asymptomatic patients. In symptomatic patients with high grade stenosis, it is highly cost effective because of its great efficacy in reducing stroke (17% absolute risk reduction).¹ In contrast, in asymptomatic patients, it is calculated that 19 carotid endarterectomies are needed to prevent one stroke in five years,⁴ leading commentators to question its cost effectiveness in these patients.⁷ However, the dilemma is that most patients experience no warning symptoms of stroke, and if preventive measures are to have an impact they need to be directed to the asymptomatic population as well as the symptomatic population.²⁴
As our study involved only 59 patients, it can be regarded as only a pilot study. However, it confirms the conclusions of overseas studies that carotid endarterectomy can be performed safely with use of only basic resources.^8-10,12,13 Since this study, a further 108 consecutive patients have undergone carotid endarterectomy performed by B M B with overnight stay. We have had no reason to alter the overnight policy. Proponents of alternative treatments for carotid bifurcation disease, such as carotid angioplasty and stenting, will not only have to prove the efficacy of these procedures, but will also need to justify the costs of using cerebral angiography (often more than once), disposables (sheaths, wires, angiography catheters, angioplasty balloons, contrast agents) and stents, together with the costs of any short or long term complications.
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(Received 20 Feb, accepted 26 Sep, 1997)