Eur J VascSurg 6, 685-687 (1992)
Correspondence Autumnal Aneurysmal Ruptures
References
Sir, The paper by Liapis et al. (Eur I Vasc Surg 1992; 6: 416418) resurrects an interesting point, first raised by Castleden et al.,1 of whether there is a seasonal variation in the incidence of ruptured abdominal aortic aneurysms, and they found more ruptures during the autumn. There are some problems with the article, however:
1 CASTLEDENWM, MERCER JC AND MEMBERS OF THE WEST AUSTRALIAN VASCULARSERVICE,Abdominalaorticaneurysmsin Western
Definition of rupture. Not all cases were ruptured. Some were found to have an acute expansion at the time of operation. The size of this group is not known but these patients must obviously be excluded when dealing with ruptures. Also, the frequency of emergency admissions does not necessarily correlate with the incidence of rupture.
Australia: descriptiveepidemiologyand patterns of rupture. Br J Surg 1989;76: 418. 2 JOHANSSONG, SWEOENBORGJ. Rupturedabdominalaorticaneurysms: a study of incidenceand mortality.Br J Surg 1986;73: 101103.
Seasonal Variation in the Incidence of Ruptured A b d o m i n a l Aortic A n e u r y s m
Sir, We read with interest the recent article by Liapis et al. on the seasonal variation in the incidence of ruptured Background population. It is not clear whether if the abdominal aortic aneurysm (AAA) in Greece. 1 This patients were recruited from a stable background and the previous report from Australia by Castleden population or whether emergency admissions to et al. 2 have highlighted an increased rate of aneurysm other hospitals in Athens could influence their rupture in their autumn and winter possibly related results. Further, operations for ruptured abdominal to cold weather changes. In a similar study of the rate of ruptured AAA in aortic aneurysms only reflect the tip of an iceberg, since the majority die before reaching hospital. To the more temperate climate of Leicestershire in the reach to the correct incidence, it is necessary to U.K., we have also found a raised incidence during identify all community and hospital ruptures within a a u t u m n but with an additional peak occurring in defined geographical area, with a high autopsy rate early spring. Meteorological data showed no correto confirm the diagnosis. We analysed the situation in lation between mean air temperature and the rate of Malta6 from 1971 to 1986, during which time the aneurysm rupture. When the rate of change in temautopsy rate was 85%. There were 215 ruptured ab- perature was considered this showed a close corredominal aortic aneurysms, defined as blood outside lation with the incidence of aneurysm rupture during the aortic wall. No seasonal variations were found the spring but not during autumn. The full explanawhich is in accordance with another population base tion for these seasonal changes would appear therestudy from Sweden. 2 fore to involve more than climatic variation. Changes in blood pressure, vascular resistance and plasma noradrenaline levels would seem to 25~ favour an increased incidence of ruptured AAA during the winter. 3 The absence of any such peak in 2O our study and that of Liapis et al. suggests that the magnitude of such changes may be insufficient to ochange the rates of aneurysm rupture. ,° Whilst these peaks in the incidence of ruptured AAA are interesting, the explanation for their occurrence remains unknown. At a practical level, meteorological data does not suggest that the surgical M A S 0 N D F M team should expect a rush of ruptured aneurysms M o n t h ( year after a particularly sharp frost during the previous night! K. Varty, A. Reid and P. R. F. Bell Henrik Bengtsson and David Bergqvist Leicester, U.K. Maim& Sweden 0950-821X/93/060685+03 $08.00/0© 1993Grune & StrattonLtd.
Correspondence
686
Proxilene
References 1 LIAP1SC, SECHASM, ILIOPOULOSD, et al. Seasonal variation in the incidence of ruptured abdominal aortic aneurysm. Eur J Vasc Surg 1992; 6: 416-418. 2 CASTLEDENWM, MERCERJC, MEMBERSOF THE WESTERNAUSTRALIAN VASCULARSERVICE. Abdominal aortic aneurysms in Western Australia: descriptive epidemiology and patterns of rupture. Br J Surg 1985; 72: 109-112. 3 Izzo JL, LARRABEEPS, SANDER E, LILLIS LM. Haemodynamics of seasonal adaptation. Am J Hypertens 1990; 3: 405-407.
Injection
I00
E E
5O Popaverine
Q.
I00
External Carotid Air Bubbles detected by Transcranial Doppler Sir, I read with interest the recent paper by Cassidy et al. on The Carotid Stump Syndrome. 1 I would like to support their theory that in the presence of an internal carotid artery occlusion, the external carotid artery can act as a conduit for persistent micro-embolisation. We have employed transcranial Doppler monitoring routinely in over fifty carotid endarterectomies. On completion of the endarterectomy it is our practice to flush the common carotid artery up the external carotid artery before releasing the internal carotid artery. This has resulted in significant cerebral embolisation detected by the Doppler in more than 10% of cases. These emboli were probably air, and no neurological sequelae resulted from them, but we are now very careful to perform a neat endarterectomy of the external carotid artery origin as well, and to back flush it before closing the arteriotomy. J. D. Beard Sheffield, U.K.
Reference 1 CASSIDY L, GRACE PA, BOUCHIER-HAYES J. The Carotid Stump Syndrome. Eur J Vasc Surg 1992; 6: 368-370.
Naftidrofluryl Dose and Vascular Resistance Sir, I read with interest the article by Davies et al. in which 60 mg of Praxilene (Naftidrofluryl oxyalate) was used intraoperatively by bolus intrarterial injection to augment blood flow in femoro-distal bypass grafts. 1 During a study of peripheral vascular resistance, the methodology of which has previously been deEur J Vasc Surg Vol 6, November 1992
50
I
I
65s
scribed in this journal, 21 compared the effect of 10 mg Praxilene and 40 mg Paparerine sulphate on vascular resistance in the popliteal artery in nine patients. Praxilene 10 mg reduced vascular resistance by 28 + 8% (mean + SD) compared to the reduction of 55 + 11% observed following Papaverine sulphate 40 mg (p < 0.001, Mann-Whitney U test). The reduction in resistance following Praxilene was brief in duration compared to that observed following Papaverine. The figure shows the effects of these two drugs on vascular resistance in the popliteal artery of one of the patients studied, resistance being directly proportional to the pressure displayed on the vertical axis. Graham G. Cooper Aberdeen, Scotland
References 1 DAVIESAH, MAGEE TR, BAIRDRN, HORROCKS M. Praxilene (naftidrofluryl oxalate) as an alternative for the augmentation of femoro-distal bypass blood flow. Eur J Vasc Surg 1992; 6: 299301. 2 COOPER GC, AUSTIN C, FITZSIMMONS E, BRANNIGANPD, HOOD JM, BARROS D'SA AAB. Outflow vascular resistance and early occlusion of infra-inguinal bypass grafts. Eur J Vasc Surg 1990; 4: 279-283.
Higher Naftidrofluryl Dose Equivalent to Papaverine Sir, The letter by Mr Cooper raises several points. Our
Correspondence Autumnal Aneurysmal Ruptures
References
Sir, The paper by Liapis et al. (Eur I Vasc Surg 1992; 6: 416418) resurrects an interesting point, first raised by Castleden et al.,1 of whether there is a seasonal variation in the incidence of ruptured abdominal aortic aneurysms, and they found more ruptures during the autumn. There are some problems with the article, however:
1 CASTLEDENWM, MERCER JC AND MEMBERS OF THE WEST AUSTRALIAN VASCULARSERVICE,Abdominalaorticaneurysmsin Western
Definition of rupture. Not all cases were ruptured. Some were found to have an acute expansion at the time of operation. The size of this group is not known but these patients must obviously be excluded when dealing with ruptures. Also, the frequency of emergency admissions does not necessarily correlate with the incidence of rupture.
Australia: descriptiveepidemiologyand patterns of rupture. Br J Surg 1989;76: 418. 2 JOHANSSONG, SWEOENBORGJ. Rupturedabdominalaorticaneurysms: a study of incidenceand mortality.Br J Surg 1986;73: 101103.
Seasonal Variation in the Incidence of Ruptured A b d o m i n a l Aortic A n e u r y s m
Sir, We read with interest the recent article by Liapis et al. on the seasonal variation in the incidence of ruptured Background population. It is not clear whether if the abdominal aortic aneurysm (AAA) in Greece. 1 This patients were recruited from a stable background and the previous report from Australia by Castleden population or whether emergency admissions to et al. 2 have highlighted an increased rate of aneurysm other hospitals in Athens could influence their rupture in their autumn and winter possibly related results. Further, operations for ruptured abdominal to cold weather changes. In a similar study of the rate of ruptured AAA in aortic aneurysms only reflect the tip of an iceberg, since the majority die before reaching hospital. To the more temperate climate of Leicestershire in the reach to the correct incidence, it is necessary to U.K., we have also found a raised incidence during identify all community and hospital ruptures within a a u t u m n but with an additional peak occurring in defined geographical area, with a high autopsy rate early spring. Meteorological data showed no correto confirm the diagnosis. We analysed the situation in lation between mean air temperature and the rate of Malta6 from 1971 to 1986, during which time the aneurysm rupture. When the rate of change in temautopsy rate was 85%. There were 215 ruptured ab- perature was considered this showed a close corredominal aortic aneurysms, defined as blood outside lation with the incidence of aneurysm rupture during the aortic wall. No seasonal variations were found the spring but not during autumn. The full explanawhich is in accordance with another population base tion for these seasonal changes would appear therestudy from Sweden. 2 fore to involve more than climatic variation. Changes in blood pressure, vascular resistance and plasma noradrenaline levels would seem to 25~ favour an increased incidence of ruptured AAA during the winter. 3 The absence of any such peak in 2O our study and that of Liapis et al. suggests that the magnitude of such changes may be insufficient to ochange the rates of aneurysm rupture. ,° Whilst these peaks in the incidence of ruptured AAA are interesting, the explanation for their occurrence remains unknown. At a practical level, meteorological data does not suggest that the surgical M A S 0 N D F M team should expect a rush of ruptured aneurysms M o n t h ( year after a particularly sharp frost during the previous night! K. Varty, A. Reid and P. R. F. Bell Henrik Bengtsson and David Bergqvist Leicester, U.K. Maim& Sweden 0950-821X/93/060685+03 $08.00/0© 1993Grune & StrattonLtd.
Correspondence
686
Proxilene
References 1 LIAP1SC, SECHASM, ILIOPOULOSD, et al. Seasonal variation in the incidence of ruptured abdominal aortic aneurysm. Eur J Vasc Surg 1992; 6: 416-418. 2 CASTLEDENWM, MERCERJC, MEMBERSOF THE WESTERNAUSTRALIAN VASCULARSERVICE. Abdominal aortic aneurysms in Western Australia: descriptive epidemiology and patterns of rupture. Br J Surg 1985; 72: 109-112. 3 Izzo JL, LARRABEEPS, SANDER E, LILLIS LM. Haemodynamics of seasonal adaptation. Am J Hypertens 1990; 3: 405-407.
Injection
I00
E E
5O Popaverine
Q.
I00
External Carotid Air Bubbles detected by Transcranial Doppler Sir, I read with interest the recent paper by Cassidy et al. on The Carotid Stump Syndrome. 1 I would like to support their theory that in the presence of an internal carotid artery occlusion, the external carotid artery can act as a conduit for persistent micro-embolisation. We have employed transcranial Doppler monitoring routinely in over fifty carotid endarterectomies. On completion of the endarterectomy it is our practice to flush the common carotid artery up the external carotid artery before releasing the internal carotid artery. This has resulted in significant cerebral embolisation detected by the Doppler in more than 10% of cases. These emboli were probably air, and no neurological sequelae resulted from them, but we are now very careful to perform a neat endarterectomy of the external carotid artery origin as well, and to back flush it before closing the arteriotomy. J. D. Beard Sheffield, U.K.
Reference 1 CASSIDY L, GRACE PA, BOUCHIER-HAYES J. The Carotid Stump Syndrome. Eur J Vasc Surg 1992; 6: 368-370.
Naftidrofluryl Dose and Vascular Resistance Sir, I read with interest the article by Davies et al. in which 60 mg of Praxilene (Naftidrofluryl oxyalate) was used intraoperatively by bolus intrarterial injection to augment blood flow in femoro-distal bypass grafts. 1 During a study of peripheral vascular resistance, the methodology of which has previously been deEur J Vasc Surg Vol 6, November 1992
50
I
I
65s
scribed in this journal, 21 compared the effect of 10 mg Praxilene and 40 mg Paparerine sulphate on vascular resistance in the popliteal artery in nine patients. Praxilene 10 mg reduced vascular resistance by 28 + 8% (mean + SD) compared to the reduction of 55 + 11% observed following Papaverine sulphate 40 mg (p < 0.001, Mann-Whitney U test). The reduction in resistance following Praxilene was brief in duration compared to that observed following Papaverine. The figure shows the effects of these two drugs on vascular resistance in the popliteal artery of one of the patients studied, resistance being directly proportional to the pressure displayed on the vertical axis. Graham G. Cooper Aberdeen, Scotland
References 1 DAVIESAH, MAGEE TR, BAIRDRN, HORROCKS M. Praxilene (naftidrofluryl oxalate) as an alternative for the augmentation of femoro-distal bypass blood flow. Eur J Vasc Surg 1992; 6: 299301. 2 COOPER GC, AUSTIN C, FITZSIMMONS E, BRANNIGANPD, HOOD JM, BARROS D'SA AAB. Outflow vascular resistance and early occlusion of infra-inguinal bypass grafts. Eur J Vasc Surg 1990; 4: 279-283.
Higher Naftidrofluryl Dose Equivalent to Papaverine Sir, The letter by Mr Cooper raises several points. Our
