The effect of lipid lowering on the incidence of recurrent carotid stenosis

Factors Affecting Recurrent Carotid Stenosis

Recurrent carotid stenosis is an ongoing process that may develop at or near the site of an operational or interventional procedure to treat an atheromatous stenosis. Although such a restenosis is most often initially without symptoms, as the disease progresses it may become symptomatic, and thus endanger the patient's life. Such patients are therefore candidates for revisional surgery. Extensive research investigation and numerous studies have incriminated several risk factors as predisposing conditions for recurrent carotid stenosis. The definite role of each predisposing factor, however, is still widely debated. Clarifying the extent of involvement of each factor in the pathogenesis of carotid restenosis is indeed demanding, as it would contribute enormously to the identification of the group of high-risk patients, and, therefore, determine the therapeutic approach in these patients.

Determinants of carotid endarterectomy anatomic durability: Effects of serum lipids and lipid-lowering drugs

OBJECTIVES

Carotid endarterectomy (CEA) remains the gold standard for treatment of carotid stenosis. With inevitable comparisons of catheter-based therapy to all aspects of CEA, this study of a large contemporary series was undertaken to evaluate the determinants of anatomic durability of CEA.

METHODS

During the interval (1989 through 1999), 2,127 primary, isolated CEAs with selective patching (50.2%) were performed in 1,853 patients (61.8% male, 36.1% symptomatic). End points included patient longevity and perioperative morbidity as well as evidence of CEA anatomic durability as defined by duplex evaluation: CEA restenosis (moderate, >50%, or greater recurrent stenosis), which included CEA anatomic failure (severe, >70%, restenosis/carotid occlusion). The incidence of CEA recurrent stenosis was temporally assessed early (<2 years) and late (>2 years) after operation. Clinical and surgical variables potentially associated with the study endpoints were analyzed by univariate and multivariate methods.

RESULTS

The perioperative stroke and death rate was 1.4% and the 2-year and 10-year survival was 88.1% and 44.9%, respectively. Anatomic failure after CEA developed in 3.9% at 2 years and in 8.5% at 5 years; only 3.2% of CEA patients underwent reoperation during a mean follow-up of 73.4 months. Early (<2 years) analysis revealed 12.2% restenosis, whereas late (>2 years) results identified 9.8% progression of carotid stenosis and a 5.8% rate of anatomic failure. Multivariate analysis determined elevated creatinine (odds ratio [OR], 1.719, P < .001) and female gender (OR, 1.564; P < .02) correlated with early restenosis. Surgical patch closure and lipid-lowering drugs were protective for both early restenosis, with ORs of 0.543 (P < .0.001) and 0.601 (P < .007) and early anatomic failure ORs of 0.469 (P < .02) and 0.517 (P < .03), respectively. Although only elevated serum cholesterol (OR, 1.009; P < .03) correlated with late anatomic failure, only lipid-lowering drugs were protective for both late freedom from progression of disease (OR, 0.202; P < .0002) or late CEA anatomic failure (OR, 0.128; P < .0003).

CONCLUSIONS

The association of female gender and elevated cholesterol with recurrent carotid stenosis is confirmed, elevated creatinine is introduced as a risk factor, and surgical patch repair is protective for early CEA recurrent carotid stenosis. The unique findings of the significant, beneficial effects of lipid-lowering drugs on both early and late CEA anatomic durability and patient survival indicate that such therapy should be instituted in most patients after CEA.

Vessel wall and flow characteristics after carotid endarterectomy: eversion endarterectomy compared with Dacron patch plasty

OBJECTIVES

Experimental studies have demonstrated that decreases in vessel wall compliance and increases in turbulence may contribute to (re)stenosis. We studied vessel wall and flow characteristics after endarterectomy with Dacron patch plasty and after eversion endarterectomy, and compared those findings with the characteristics of non-stenotic, unoperated carotid arteries (controls).

METHODS

Seventy-four patients who underwent 84 carotid endarterectomies were studied postoperatively by ultrasonography (2-24 months) Recorded variables included the diameter of the bulb, strain, elastic modulus (stiffness), and presence of turbulent flow.

RESULTS

The vessel wall and flow characteristics of the two groups differed significantly. The diameter was higher and the strain lower in Dacron patch plasty than in controls; eversion endarterectomy did not differ from controls. The elastic modulus was higher (stiffer) in Dacron patch plasty than in eversion endarterectomy; neither Dacron patch plasty nor eversion endarterectomy differed significantly from controls. The stiffness index was not significantly different between the groups. Turbulence was present in Dacron patch plasty and eversion endarterectomy when compared with controls.

CONCLUSION

In diameter, strain and stiffness, the operated carotid artery resembles the non-stenotic, unoperated artery more closely after eversion endarterectomy than after Dacron patch plasty.

The prevention of cardiovascular disease. Emphasis on secondary prevention

Atherosclerosis is a progressive disease affecting all major arteries. Clinical evidence of atherosclerosis increases the risk of subsequent morbid and mortal events fivefold to sevenfold over the next 5 to 10 years. The same risk factors contribute to the initial development of CVD events as to their recurrence. Both coronary and noncoronary events, such as stroke or PAD, reflect the severity of the underlying atherosclerotic process and strongly predict future excess CVD morbidity and mortality. Short-term and long-term survival depends on modifying the risk factors that contribute to CVD events. Although absolute proof of benefit for secondary prevention does not exist for all risk factors, the data from primary prevention trials and the secondary prevention trials that have been done argue strongly for aggressive intervention. Benefit has been demonstrated for smoking cessation, cholesterol reduction, and blood pressure control. Selected patients may benefit from additional medical, procedural, or surgical interventions to prolong life, such as beta-blocking agents, aspirin, or carotid endarterectomy. Many secondary prevention measures are a cost-effective way to reduce the substantial morbidity and mortality due to CVD. Contrary to primary prevention, even modest treatment effects from secondary prevention efforts can benefit large numbers of patients. Finally, secondary prevention may be more successful because patients with clinical evidence of CVD may be more highly motivated than their healthy counterparts to make and maintain lifestyle changes.

The influence of smoking and lipids on restenosis after carotid endarterectomy

Factors associated with restenosis were investigated in 107 patients undergoing carotid endarterectomy for symptomatic disease. The patients, 71 men and 36 women with mean age 68 +/- 8 years, were followed up for 1 year by serial Duplex scanning. Carotid restenosis of > or = 50% developed in 18 patients (17%), 11 men and seven women. Restenosis was not influenced by age, sex, diabetes or hypertension. Continuing smokers, serum cotinine > 200 nmol/l, had a significantly higher incidence of > or = 50% restenosis after 1 year (39%), compared with only 16% of non-smokers, p = 0.023. Restenosis > or = 50% also was associated significantly with below median body mass index (p = 0.027). Women undergoing carotid endarterectomy had higher levels of cholesterol (median 7.4 mmol/l) and apolipoprotein B (median 0.81 g/l) than men (median cholesterol 6.4 mmol/l, median apolipoprotein B 0.69 g/l), p < 0.01. For men only, restenosis of > or = 50% was associated with low levels of serum cholesterol (median 5.7 mmol/l), p = 0.002. For women cholesterol levels were higher (median 8.1 mmol/l) in those with > or = 50% restenosis. Smoking adversely influences early restenosis (1 year) after carotid endarterectomy. Hyperlipidaemia is not a risk factor for restenosis in men, but may be associated with restenosis in women.