Forearm vessel atherosclerosis. A harbinger of carotid disease?

Abstract

Objectives. Atherosclerosis is a systemic disease affecting several vessels of the body. Coronary artery patients requiring bypass surgery have increased prevalence of carotid artery atherosclerosis which is known to increase operative risk in coronary artery bypass surgery (CABG). Radial artery is often screened for grafting purposes preoperatively. Our aim was to find out whether atherosclerotic changes in forearm vessels are correlated and could reveal risk to carotid artery disease. Design. Eighty-five patients planned for elective CABG were examined with ultrasonography preoperatively. Biplane ultrasonographic scanning was performed on forearm arteries and both carotid arteries. Results. Eleven patients had pathologic changes in the wall of forearm vessels. Carotid artery disease was found on 19 patients. Forearm vessel pathology was found to have correlation to carotid artery disease. When forearm arteries show atherosclerotic pathology the risk of having carotid disease is at least five-fold, in subgroups even higher. Conclusions. Forearm arterial pathology is correlated to carotid artery disease. When forearm vessel pathology is evident in preoperative examination, scanning of the carotid vessels should be considered.

• Radial artery
• coronary artery bypass grafting
• ultrasonography

Atherosclerosis is a systemic disease affecting often several vessels of the body. One well known site of predilection is coronary arteries and coronary artery disease (CAD) results in approximately 3 300 coronary artery bypass grafting operations (CABG) annually in Finland. Radial artery is frequently used as a bypass graft in these operations.

Atherosclerosis also affects carotid arteries. The correlation between CAD and carotid artery atherosclerosis is well established in earlier studies 1. The carotid vessels are closely related to other supra-aortic vessels which are in direct continuation to the vessels of the forearm. We have earlier studied the usefulness of radial artery as a bypass graft and evaluated the atherosclerotic changes in forearm arteries in subjects planned for CABG 2. To our knowledge there are only few studies indicating the relationship of atherosclerotic changes in the forearm arteries and carotid arteries 3, 4.

Our aim with this study was to find whether pathologic changes in the wall of the forearm vessels are correlated to carotid atherosclerosis in patients with coronary artery disease.

Material and methods

Between October 2000 and April 2005, 85 patients planned for elective CAGB were enrolled to this study. Patients older than 60 years and emergency cases were excluded. Mean age of the patients was 52.2 (SD 4.7) years. Male gender was predominant (75 vs. 10). Thirty-five smokers were identified among patients and 20 of all were diabetics. Five of the diabetics were treated with insulin, 15 had oral anti-diabetic medication.

Patients underwent biplane ultrasonographic study of both carotid arteries. Radial and ulnar arteries of the non-dominant forearm were scanned with ultrasonography as well. Calcification of the intima, sclerosis of the media and vascular anomalies were recorded on all vessels. Doppler ultrasonography was performed with a transducer with emission frequency between 5 and 10 MHz, based on best visibility (Aloka, Pro Sound 5500). Additionally, changes in carotid arteries were classified as follows: no sclerosis, sclerotic changes without stenosis, mild stenosis (1–15%), moderate stenosis (16–49%), significant stenosis (50–75%), severe stenosis (76–99%) and total occlusion.

Correlation between atherosclerotic changes in carotid and forearm vessels was analysed using SPSS 15.0 software.

Results

Intimal calcified plaques were found on four patients in radial artery and on seven patients in ulnar artery. On three patients both forearm arteries were found to have intimal calcifications. Two patients had sclerotic changes in the medial layer of both forearm arteries. There where two patients with isolated ulnar sclerosis of the media and two patients with corresponding finding in radial artery. Vessel wall pathology was present on six patients in radial artery and on eight patients in ulnar artery. On three patients there was both radial and ulnar artery engagement. Altogether 11 patients (12.9%) had pathologic changes in the wall of forearm vessels.

Atherosclerotic changes in carotid arteries were found 13 patients (15.3%) on the right side and on 19 patients (22.4%) on the left side. Thirteen patients (15.3%) had bilateral findings on their carotid arteries on the ultrasonographic scanning. Carotid disease was either bilateral or isolated to the left side. There were no patients with isolated right sided carotid disease. Ultrasonographic findings on patients with forearm and carotid artery pathology are summarised in Table I.

Table I.  Ultrasonographic findings on patients with forearm artery pathology.

Nr	Radial artery	Ulnar artery	Carotid arteries
1	Calcification	Calcification
2	Calcification	Calcification	Mild stenosis on left
3	Calcification + sclerosis	Calcification + sclerosis	Mild stenosis on both
4	Calcification + sclerosis	Calcification + sclerosis	Total occlusion on right, significant on left
5	Sclerosis
6	Sclerosis		Significant stenosis on both
7		Sclerosis
8		Sclerosis
9		Calcification	Mild stenosis on both
10		Calcification
11		Calcification

Mild stenosis 1–15%, significant 50–75%, total occlusion 100%.

Smoking and diabetes had no statistically significant correlation neither to forearm vessel or carotid pathology. Results of risk factor analysis are summarised in Table II. Age did not have any correlation either. However, there was correlation between forearm vessel pathology and carotid atherosclerosis. When pathologic changes in forearm vessels were evident the risk of having carotid atherosclerosis was at least five fold. If these the changes were confined to radial artery only the correlation was even stronger. Statistical significance was found in both cases. Same is true even in isolated cases of ulnar involvement. Results of statistical analysis are summarised in Table III.

Table II.  Correlation of diabetes and smoking to vessel pathology.

	P-value	Odds ratio	95% CI
Smoking and carotid arteries	0.19	0.43	0.14–1.33
Smoking and forearm arteries	0.51	0.49	0.12–2.00
Diabetes and carotid arteries	0.14	2.39	0.78–7.23
Diabetes and forearm arteries	0.28	2.07	0.53–7.97

CI: confidence interval.

Table III.  Results of statistical analysis. Correlation between forearm vessel pathology and carotid artery pathology.

	P-value	Odds ratio	95% CI
Radial artery disease	0.021	8.5	1.42–51.0
Ulnar artery disease	0.012	7.5	1.60–35.1
Disease in both UA and RA	0.013	5.6	1.49–21.3

CI: confidence interval.

Discussion

Radial artery is often used as a bypass conduit in coronary artery surgery. It is screened preoperatively with various techniques, which have been investigated earlier in numerous studies. Based on our own results we recommend the use of ultrasonographic scanning in selected cases 2. Some authors even suggest that ultrasonographic examination should be mandatory 5. The higher prevalence of carotid atherosclerosis in patients with coronary artery disease is well known and the presence of carotid stenosis is known to increase the operative risk in coronary surgery. Many studies have been performed to identify patients with carotid disease preoperatively 6, 7. In the cases where the forearm is examined with ultrasonography preoperatively and pathologic changes are found, atherosclerotic involvement of the carotid arteries would be very interesting to study.

Gaudino and colleagues involved 42 patients with coronary disease and 26 control patients in their study where they measured intima-media thickness (IMT) of the radial artery and common carotid artery with ultrasonography 3. Intima-media thickness is thought to be an early marker for atherosclerosis. They found no statistical correlation between the radial artery IMT and common carotid IMT either in CAD patients or in controls (p-values 0.06 and 0.20, respectively). The authors conclude that the atherosclerotic involvement in radial artery is far less severe than in common carotid artery.

Pathologic changes in the wall of radial artery and factors associated with it have been studied by Ruengsakulrach and colleagues 4. In their series of 73 patients they identified risk factors predicting the radial artery calcification. Age, sex and the presence of carotid disease were identified. Only carotid disease was shown to be involved and it was of borderline statistical significance (p-value 0.08, odds ratio 3.3, 95% confidence interval 0.9-13). The incidence of radial artery abnormalities was 31.5% in a material where mean age of the patients was 67 years. Their findings suggest that patients with carotid disease have high risk for radial artery calcification and care should be taken when using radial artery as a bypass graft in such patients.

In our study we failed to establish the association of age, diabetes and smoking to atherosclerotic changes in the studied vessels. This is probably due to the fairly young patients in our material. It should be kept in mind, however, that all patients had significant coronary artery disease as they were planned for CABG. Young patients often have, in addition to acquired risk factors, a strong genetic predisposition to the atherosclerotic disease. In these cases it is possible that the genetic burden overweighs the burden of acquired risk factors.

Intimal calcifications are related with atherosclerosis whereas the role of medial calcifications is not evenly clear. As it has been pointed out earlier, ultrasonography is not very good at differentiating between intimal and medial calcifications. Therefore we chose to treat the intimal and medial changes as one entity.

The incidence of radial artery pathology in our study was 7.1% which is considerably lower than in an earlier study. The overall incidence of forearm vessel pathology was 11%. Again, our patients are young and their disease has not advanced to a significant level. Therefore, it is interesting that even though our patients are relatively young with only moderate atherosclerotic involvement in forearm vessels this involvement is correlated to carotid artery disease and despite the small population size the correlation was statistically significant. Radial artery atherosclerotic involvement is a marker that predicts carotid artery disease. When found, pathological radial artery should necessitate at least an evaluation of carotid vessels. It remains to be seen if this correlation applies a series of elderly patients.

We conclude that atherosclerotic involvement of the forearm arteries is correlated to carotid artery disease even in a fairly young population of elective patients with coronary artery disease.

Acknowledgements

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.