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J Am Coll Cardiol, 2003; 42:211-216, doi:10.1016/S0735-1097(03)00579-5 © 2003 by the American College of Cardiology Foundation |
* Department of Cardiovascular Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
Manuscript received December 9, 2002; revised manuscript received January 6, 2003, accepted January 30, 2003.
* Reprint requests and correspondence: Dr. Hiroyuki Tsutsui, Department of Cardiovascular Medicine, Kyushu University Graduate School of Medical Sciences, 3-1-1 Maidashi, Higashi-ku, Fukuoka, 812-8582, Japan.
prehiro{at}cardiol.med.kyushu-u.ac.jp
| Abstract |
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BACKGROUND: Cholesterol embolization syndrome is a systemic disease caused by distal showering of cholesterol crystals after angiography, major vessel surgery, or thrombolysis.
METHODS: We prospectively evaluated a total of 1,786 consecutive patients 40 years of age and older, who underwent left-heart catheterization at 11 participating hospitals. The diagnosis of CES was made when patients had peripheral cutaneous involvement (livedo reticularis, blue toe syndrome, and digital gangrene) or renal dysfunction.
RESULTS: Twenty-five patients (1.4%) were diagnosed as having CES. Twelve patients (48%) had cutaneous signs, and 16 patients (64%) had renal insufficiency. Eosinophil counts were significantly higher in CES patients than in non-CES patients before and after cardiac catheterization. The in-hospital mortality rate was 16.0% (4 patients), which was significantly higher than that without CES (0.5%, p < 0.01). All four patients with CES who died after cardiac catheterization had progressive renal dysfunction. The incidence of CES increased in patients with atherosclerotic disease, hypertension, a history of smoking, and the elevation of baseline plasma C-reactive protein (CRP) by univariate analysis. The femoral approach did not increase the incidence, suggesting a possibility that the ascending aorta may be a potential embolic source. As an independent predictor of CES, multivariate regression analysis identified only the elevation of pre-procedural CRP levels (odds ratio 4.6, p = 0.01).
CONCLUSIONS: Cholesterol embolization syndrome is a relatively rare but serious complication after cardiac catheterization. Elevated plasma levels of pre-procedural CRP are associated with subsequent CES in patients who undergo vascular procedures.
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Clinical consequences of CES vary considerably, from being completely asymptomatic to presenting acute multiorgan failure, including progressive renal failure or cutaneous involvement, with a mortality rate as high as 70% to 90% (14). However, the actual incidence of this syndrome remains uncertain. Estimates of the incidence of CES after vascular procedures have ranged from 0.15% in clinical studies (5) to 25% to 30% in pathologic series (3). Clinical studies probably underestimated the incidence because only a minority of patients can be clinically recognized. Therefore, despite the importance of this disease as a complication of percutaneous diagnostic and interventional procedures, the clinical characteristics of CES remain uncertain. Quantification of the risk factors for post-catheterization CES is critically important to both patients and physicians. However, no studies have comprehensively examined both clinical and therapeutic variables that can be applied to estimate the risk of CES in patients undergoing cardiac catheterization.
Therefore, the goals of the present study were: 1) to determine the incidence of CES after cardiac catheterization; and 2) to determine the risk factors that are independently associated with CES as complications after cardiac catheterization. For this purpose, we prospectively examined the presence of cutaneous findings, and we compared serum creatinine levels and blood eosinophil counts between pre- and post-procedure.
| Methods |
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Definition of CES. Cutaneous signs of CES including livedo reticularis, blue toe syndrome, and digital gangrene were recorded at the time of the initial procedure and two weeks after cardiac catheterization. Serum creatinine levels were also recorded before and two weeks following catheterization.
"Definite CES" was defined if the patients had cutaneous signs including livedo reticularis, blue toe syndrome, and digital gangrene with or without renal impairment. "Possible CES" was defined if patients had only renal dysfunction referring to a post-catheterization serum creatinine >1.3 mg/dl and an increase of creatinine level by >50% from the baseline value two weeks after the procedure without skin lesions (11,15) (Table 1). In the patients with chronic renal failure with hemodialysis, CES was diagnosed only in the presence of the peripheral cutaneous involvement. Several previous case reports have demonstrated that serum creatinine levels increase from a few days to a few months after the procedures (1618). Therefore, although we cannot exactly exclude the possibility of the contribution of contrast nephrotoxicity, we consider that the increase of creatinine within several days is probably due to contrast nephrotoxicity, whereas the increase of creatinine at two weeks suggests possible CES.
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220 mg/dl. Hypertension was defined as systolic blood pressure >140 mm Hg and/or diastolic blood pressure >90 mm Hg. Diabetes was defined as fasting blood sugar
140 mg/dl or blood sugar during a 75-g oral glucose tolerance test
200 mg/dl. Renal dysfunction was defined as creatinine clearance levels
50 ml/min/m2 calculated by the Cockroft-Gault formula. Multivessel disease was defined as
75% stenosis in more than two major epicardial coronary arteries. Furthermore, left ventricular ejection fraction (LVEF) was assessed by echocardiography. Coronary interventions included all catheter-based revascularization procedures such as balloon angioplasty, stent emplacement, and directional and rotational atherectomy. All patients had 3,000 to 5,000 U heparin at the beginning of the procedure. Patients were classified as "anticoagulated" when heparin or warfarin was continued for more than 24 h after the procedures. No patient received thrombolytic agents in the present study. Death and the need for hemodialysis during hospitalization were recorded. Statistical analysis. Continuous variables were expressed as mean ± SD. Comparisons between patients with and without CES were made by use of unpaired t test for continuous variables and chi-square test for categorical variables. All variables that were associated with CES with a value of p < 0.05 in univariate analyses were included in the multivariate models. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated based on the multiple logistic regression analysis. All statistical analyses were performed using the SPSS (SPSS Inc., Chicago, Illinois) or StatView (SAS Institute, Cary, North Carolina), and p values < 0.05 were considered statistically significant.
| Results |
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1.0 mg/dl) in plasma CRP levels. Plasma CRP level as a continuous variable was also an independent risk factor of CES (p < 0.01).
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| Discussion |
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Some case reports have shown a transient eosinophilia in up to 80% of patients with CES (13,19). Similarly, in our study population, the eosinophil counts were significantly higher in CES patients than in non-CES patients before and after cardiac catheterization. Furthermore, CES with renal dysfunction showed greater increase of eosinophil counts (from 220 to 535/µl) compared to those patients without renal dysfunction (from 302 to 339/µl). All patients who did not survive in the CES group had renal dysfunction after catheterization, suggesting that renal insufficiency in CES is critical. The present study showed an in-hospital mortality of 16%. Most previous case reports of CES described diffuse embolism and multiorgan failure, and hence reported a mortality of 70% to 90% (14,20). The difference between the present study and previous case series may be due to the fact that our study population included subtle cases of CES. Nonetheless, CES remained a condition associated with a high mortality.
This study identified independent pre-procedural predictors of CES. The syndrome occurred more frequently in patients with generalized atherosclerosis such as multiple-vessel coronary disease and cerebrovascular disease shown by univariate analysis. In particular, the variable identified as an independent predictor of CES was a higher level of plasma CRP, indicating an important association between systemic inflammation and CES. Several studies including our own have demonstrated an important role of inflammation in the initiation and progression of atherosclerosis in human and animal models (2125). The mechanism of how inflammation leads to CES is unknown, but our present findings may extend previous observation regarding inflammation as an important cardiovascular risk factor (2125). The vulnerable atherosclerotic plaques contain a large amount of inflammatory cells, including macrophages (26), and such plaques can be the source of cholesterol embolization. Elevated levels of CRP may reflect enhanced immune or inflammatory activity of atherosclerotic lesions in these patients. Our findings may raise the possibility that strategies to minimize vascular inflammation can reduce the occurrence of CES in these patients. Treatment with HMG-CoA reductase inhibitors (statins) might be effective as a prophylaxis because it can reduce systemic inflammation independent of decreasing plasma cholesterol levels (2729). Further studies are needed to investigate the usefulness of therapeutic strategies for systemic inflammation in the prevention of CES.
Several case reports have suggested that patients are more likely to develop CES when they are anticoagulated; therefore, they are recommended to discontinue anticoagulation when CES is suspected to be present (6,30). However, studies suggesting a relation between anticoagulation and CES were retrospective, and the results may have been confounded by the use of anticoagulants to treat the syndrome (31). Although anticoagulation may allow cholesterol crystals to embolize freely, the present study did not indicate any significant association between the use of anticoagulants and CES. This is in agreement with a report using transesophageal echocardiography, in which the risk of clinically apparent CES was as low as 0.7% during warfarin therapy in patients with aortic atheromas and atrial fibrillation (32).
The abdominal aorta is one of the most heavily involved areas with atherosclerotic plaques; therefore, procedures involving mechanical injury by catheters to these regions could potentially disrupt plaque material and induce CES (4). Hence, we suspect that the frequency of CES is lowered if procedures are performed via the brachial artery approach (33); however, there were no significant differences in the prevalence of the femoral approach with and without CES. Therefore, it is possible that the ascending thoracic aorta may potentially be a main embolic source of cholesterol crystals causing CES.
Study limitations. Several limitations should be acknowledged in this study. First, only the cutaneous manifestations and renal impairment were used for the diagnosis of CES, but histological confirmation was not required in this study. Even though the biopsy of characteristic cutaneous and renal lesions is helpful, less than 50% of patients show typical findings (31). Furthermore, histological presence of cholesterol embolization does not always result in clinically specific CES (31). We thus consider that biopsy is useful but not necessary to confirm the CES diagnosis.
Second, we defined renal impairment with CES as more than 50% worsening of serum creatinine levels referred from the previous study (11) and thereby we may have overestimated its true frequency. Third, we employed serum creatinine data two weeks after the procedure because previous case reports have shown that serum creatinine levels increase several days after the procedure (1618). Furthermore, the decline in renal function immediately after the procedure may not be due to CES but, more likely, to other causes such as contrast nephrotoxicity or hypotension.
Moreover, there was no significant difference in the use of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II receptor blockers (ARB) between CES and non-CES groups in our study patients. Therefore, we consider that the contribution of renal toxicity by ACEI or ARB may be excluded. However, as we could not completely exclude the possible contribution of some other causes, we diagnosed patients as possible CES if they had only renal impairment without cutaneous signs.
Finally, although there was no significant difference in the use of aspirin or statins at the time of procedure, we could not provide data concerning the duration and the dosage of aspirin or statins that were used before and after cardiac catheterization in our study patients.
Conclusions. Finally, CES often occurs after a vascular procedure in patients with systemic inflammation. It is not a rare occurrence, but it is infrequently recognized. Clinical manifestations range from mild to catastrophic. Elevated baseline CRP levels can identify patients who are at higher risk of post-catheterization CES. Better understanding and early recognition of this disease are expected to reduce patient mortality and morbidity after cardiac catheterization.
| APPENDIX |
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| Acknowledgments |
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| References |
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