Carotid endarterectomy: an underutilized means of stroke prevention
Sir
While we agree with Mr Irvine and colleagues (Br J Surg 1996; 83: 1373-4) that carotid endarterectomy (CEA) is an underutilized tool in the prevention of stroke we have two points to raise regarding their recent paper.
First, there is a discrepancy between the data quoted regarding CEA in Scotland and the results of our own recent studies. Using data supplied by the Information and Statistics Division of the National Health Service in Scotland regarding CEA, and the Registrar General for Scotland regarding population, we find the number of CEAs performed in 1993 in Tayside to be 149 per million population, not 134.1 per million population as quoted. Furthermore, we find the numbers of CEA performed in Dumfries and Galloway to be 81 per million, not more than 100 per million as quoted. The CEA rate in the largest Health Board area, Greater Glasgow, was not quoted; we found it to be 152 per million.
Second, as Vascular Services in Scotland are located in only nine of 15 Health Boards, a significant proportion of patients undergoing vascular surgery travel across Health Board boundalies for treatment. The authors' analysis of CEA rate by Health Board of treatment is likely, therefore, to underestimate variation in the underutilization of CEA by Health Board of residence. Under the auspices of the Scottish Vascular Audit Group we have recently calculated the annual CEA rate per million population of each Health Board area for the period 1989-1994. In 1989, the CEA rate in Scotland ranged between zero in Highland, Orkney, Shetland and the Western Isles and 40 per million in Tayside. In 1994 the CEA rate was zero in only two regions (Orkney and Shetland) and had increased to a maximum rate of 210 per million in Tayside. These data cannot be explained by differences in the incidence of stroke between Health Boards and point to wide variation in the availability of CEA as a means of stroke reduction depending on place of residence within Scotland.