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Coronary angiography using 4 French catheters
International Journal of Cardiology 80 (2001) 5–6 www.elsevier.com / locate / ijcard
Editorial
Coronary angiography using 4 French catheters Nigel M. Wheeldon* Consultant Cardiologist, South Yorkshire Cardiothoracic Centre, Sheffield, S5 7 AU, UK Received 23 April 2001; accepted 25 April 2001
Only a few years ago coronary angiography and coronary angioplasty were routinely performed via 7F and 8F catheters respectively. Advances in catheter technology have resulted in the ability to downsize, resulting in less access site trauma and complications. Most coronary angioplasty can now be performed using 6F equipment and we have recently seen the introduction of 5F guide catheters. It should therefore be perfectly possibly to perform angiography alone using even smaller equipment. The paper by Danzi et al. [1] in this edition of the Journal is one of a number of studies evaluating the use of very small catheters in this setting. The message, from the published data we have and from those with considerable experience of the technique, is that 4F coronary angiography is feasible, reliable and associated with an extremely low incidence of groin complications. However, the technique has a long learning curve and even those with many years experience of coronary angiography should not assume that they are experts using 4F. Many fall down at this stage, often blaming the catheters for their difficulties rather than losing face. In doing so they never achieve competence in the technique. The issue of competence is important as far as randomized trials are concerned, since all published data on 4F angiography will be from operators with far greater experience of catheters larger than 4F. My own experience of over 1000 cases demonstrated a steep learning curve over at *Tel.: 144-114-2434-343; fax: 144-114-2610-350. E-mail address: [email protected] (N.M. Wheeldon).
least the first 300–400 cases. Only having passed this point would I personally feel competent to compare the 4F technique against 6F. It is after all the technique of the operator as much as the catheter that is being compared. There are a number of tricks to successful 4F angiography. Case selection is important for the best results, based on the balance between good quality images and very low access site complications. 4F angiography is not ideal for every patient, which may be a criticism of the Danzi paper [1] and others where consecutive patients have been enrolled. My own unpublished experience is that 82% of all-comers are suitable for 4F studies. However, if cases are preselected, the success of the technique will be around 98%. Patients with aortic valve disease, marked dilatation of the aortic root or LV hypertrophy (with large, thirsty coronary arteries) are often unsuitable and 6F will be appropriate from the start in most cases. Very obese patients are also usually more suited to 6F, although the benefit of very low access site complications with 4F needs to be taken into account. Local anaesthetic injections should avoid arterial puncture and the smallest possible needle used for access (larger needles result in bleeding around the 4F sheath). A scalpel incision is not necessary prior to sheath insertion, neither is the use of heparin. Imaging of the right coronary artery is almost always perfectly adequate assuming normal anatomy. The left coronary artery may be less well opacified and is the usual source of difficulty with 4F studies. Care
0167-5273 / 01 / $ – see front matter 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S0167-5273( 01 )00473-9
6
N.M. Wheeldon / International Journal of Cardiology 80 (2001) 5 – 6
should be taken to secure a firm catheter position prior to injection. The injection technique is critical. The newcomer to 4F will sense that a greater force is required to discharge the usual contrast injection. If this force is applied then catheter blowout is likely to occur due to the high velocity jet. The correct technique is to use a slower, more sustained injection to avoid this problem. This often results is less contrast delivered per injection, especially in the RCA where 3–4 mls can often be adequate. Femoral complications are very unusual. My own experience is that 4F patients can sit up in bed 30 minutes after haemostasis and can mobilize at 1 hour. This is a major benefit of the technique that has so far been underestimated in published studies due to trial design. Danzi et al. [1] have produced data that again strongly support the 4F technique. They have shown feasibility in all cases and an extremely low complication rate. Despite statistically better imaging in the 6F group, it is important to note that clinical de-
cision-making was unaffected by this. Critics would see limitations of the trial in relation to numbers, case selection and the mobilization protocol. Had cases been preselected and very short mobilization times used, then the benefit of 4F would more than likely be apparent. As long as coronary angiography remains the gold standard method of assessing coronary disease, the inexorable progression to even smaller catheters will continue. Despite a growing body of evidence to support the 4F technique, its main limitation at present is not the technology but the reluctance of operators to change their habits.
References [1] Danzi GB, Capuano C, Sesana M, Di Blasi A, Predolini S, Laterza C, Quaini E, A randomized comparison of the use of 4 and 6 French diagnostic catheters: The limits of downsizing.
Editorial
Coronary angiography using 4 French catheters Nigel M. Wheeldon* Consultant Cardiologist, South Yorkshire Cardiothoracic Centre, Sheffield, S5 7 AU, UK Received 23 April 2001; accepted 25 April 2001
Only a few years ago coronary angiography and coronary angioplasty were routinely performed via 7F and 8F catheters respectively. Advances in catheter technology have resulted in the ability to downsize, resulting in less access site trauma and complications. Most coronary angioplasty can now be performed using 6F equipment and we have recently seen the introduction of 5F guide catheters. It should therefore be perfectly possibly to perform angiography alone using even smaller equipment. The paper by Danzi et al. [1] in this edition of the Journal is one of a number of studies evaluating the use of very small catheters in this setting. The message, from the published data we have and from those with considerable experience of the technique, is that 4F coronary angiography is feasible, reliable and associated with an extremely low incidence of groin complications. However, the technique has a long learning curve and even those with many years experience of coronary angiography should not assume that they are experts using 4F. Many fall down at this stage, often blaming the catheters for their difficulties rather than losing face. In doing so they never achieve competence in the technique. The issue of competence is important as far as randomized trials are concerned, since all published data on 4F angiography will be from operators with far greater experience of catheters larger than 4F. My own experience of over 1000 cases demonstrated a steep learning curve over at *Tel.: 144-114-2434-343; fax: 144-114-2610-350. E-mail address: [email protected] (N.M. Wheeldon).
least the first 300–400 cases. Only having passed this point would I personally feel competent to compare the 4F technique against 6F. It is after all the technique of the operator as much as the catheter that is being compared. There are a number of tricks to successful 4F angiography. Case selection is important for the best results, based on the balance between good quality images and very low access site complications. 4F angiography is not ideal for every patient, which may be a criticism of the Danzi paper [1] and others where consecutive patients have been enrolled. My own unpublished experience is that 82% of all-comers are suitable for 4F studies. However, if cases are preselected, the success of the technique will be around 98%. Patients with aortic valve disease, marked dilatation of the aortic root or LV hypertrophy (with large, thirsty coronary arteries) are often unsuitable and 6F will be appropriate from the start in most cases. Very obese patients are also usually more suited to 6F, although the benefit of very low access site complications with 4F needs to be taken into account. Local anaesthetic injections should avoid arterial puncture and the smallest possible needle used for access (larger needles result in bleeding around the 4F sheath). A scalpel incision is not necessary prior to sheath insertion, neither is the use of heparin. Imaging of the right coronary artery is almost always perfectly adequate assuming normal anatomy. The left coronary artery may be less well opacified and is the usual source of difficulty with 4F studies. Care
0167-5273 / 01 / $ – see front matter 2001 Elsevier Science Ireland Ltd. All rights reserved. PII: S0167-5273( 01 )00473-9
6
N.M. Wheeldon / International Journal of Cardiology 80 (2001) 5 – 6
should be taken to secure a firm catheter position prior to injection. The injection technique is critical. The newcomer to 4F will sense that a greater force is required to discharge the usual contrast injection. If this force is applied then catheter blowout is likely to occur due to the high velocity jet. The correct technique is to use a slower, more sustained injection to avoid this problem. This often results is less contrast delivered per injection, especially in the RCA where 3–4 mls can often be adequate. Femoral complications are very unusual. My own experience is that 4F patients can sit up in bed 30 minutes after haemostasis and can mobilize at 1 hour. This is a major benefit of the technique that has so far been underestimated in published studies due to trial design. Danzi et al. [1] have produced data that again strongly support the 4F technique. They have shown feasibility in all cases and an extremely low complication rate. Despite statistically better imaging in the 6F group, it is important to note that clinical de-
cision-making was unaffected by this. Critics would see limitations of the trial in relation to numbers, case selection and the mobilization protocol. Had cases been preselected and very short mobilization times used, then the benefit of 4F would more than likely be apparent. As long as coronary angiography remains the gold standard method of assessing coronary disease, the inexorable progression to even smaller catheters will continue. Despite a growing body of evidence to support the 4F technique, its main limitation at present is not the technology but the reluctance of operators to change their habits.
References [1] Danzi GB, Capuano C, Sesana M, Di Blasi A, Predolini S, Laterza C, Quaini E, A randomized comparison of the use of 4 and 6 French diagnostic catheters: The limits of downsizing.