Surgical Treatment of Wolff -Parkinson- White Syndrome T. Bruce Ferguson, Jr, MD Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri ince 1984, Guiraudon and associates from London, S Ontario, have advocated an epicardial dissection technique for surgical ablation of accessory pathways responsible for the Wolff-Parkinson-White syndrome. Cardiopulmonary bypass has not been required for acces- sory pathways located in the right free wall and posterior septal regions of the atrioventricular (AV) groove. The fat pad in the AV groove or posterior septal space is dissected off the atrium down to the level of the annulus of the AV valve(s). Cryosurgical lesions are then applied to the annular tissue to ablate any juxtaannular accessory path- ways. Previously, application of this technique to accessory pathways located in the left free wall space was associated with hemodynamic instability owing to dislocation of the heart out of the pericardial space. In virtually all in- stances, cardiopulmonary bypass was necessary to per- form this dissection, which was begun on the atrial side of the left AV groove and carried down to the level of the mitral annulus. The circumflex coronary artery and coro- nary sinus were thus dissected “en bloc” off the left atrial wall; problems with tearing of the friable left atrial tissue or disruption of the AV groove were occasionally encoun- tered, and concerns about proximity of the circumflex coronary artery to the cryoprobe during freezing have See also page 968. been expressed. Finally, even with cardiopulmonary by- pass, exposure can be difficult, particularly in patients with enlarged hearts. These difficulties have prompted Guiraudon and asso- ciates to alter their dissection technique for left free wall pathways. Their paper in this issue of The Annals entitled “Surgical epicardial ablation of left ventricular pathway using sling exposure” [ 11 describes a method of applying an epicardial dissection technique to pathways located in the left free wall space without the need for cardiopulmo- nary bypass. To facilitate exposure, the dissection is now performed by dissecting the AV groove fat pad off the ventricle instead of the atrium. This permits better access to the AV groove tissue because the mitral annulus can be ap- proached from above rather than from below (as the heart is dislocated from the pericardium). This epicardial dis- section from the ventricular side of the AV groove was originally reported by Watanabe and associates [2]. A Address reprint requests to Dr T. Bruce Ferguson, Jr, Su’te 3108 Queeny Tower, Barnes Hospital Plaza, St. Louis, MO 63110. logical extension of this dissection technique has been to devise a method of exposure to dislocate the heart out of the pericardium that seemingly does not cause hemody- namic compromise, thus obviating the need for cardiopul- monary bypass. It is important to recognize that both the dissection technique and the exposure technique have been modi- fied; as before, attempts to perform the older “en bloc” resection technique (dissection off the atrial wall) without cardiopulmonary bypass support are not feasible. The advantages and disadvantages of the more estab- lished endocardial technique versus the “en bloc” or atrial epicardial dissection technique have been discussed for the past 5 years. Initially, the advocates of the epicardial technique stated that this approach led to a lower mor- bidity and mortality than the endocardial approach; in fact, no difference exists between the two techniques when comparable series of patients are analyzed [3, 41. The one study in which the different techniques were performed in the same institution demonstrated no differ- ences in morbidity or mortality between the techniques (51. The rationale for developing an alternative approach to the classic endocardial dissection technique for ablation of Wolff-Parkinson-Whitepathways, as stated by Guiraudon and associates [l], is as follows: avoidance of heparin, which results in bleeding during the dissection and in the postoperative period; avoidance of cardiopulmonary by- pass and its associated morbidity; and avoidance of car- dioplegic arrest. Each of these is obviously necessary for dissections on the left side of the heart using the endocar- dial technique. In the current report [l], unpublished data from their group are referenced to indicate that cardiopulmonary bypass itself is associated with a significant release of the MB fraction of creatine kinase. Although these data sug- gest that cardiopulmonary bypass is associated with myo- cardial damage, they are at odds with the generally accepted concepts regarding bypass. Clearly, hepariniza- tion of the patient produces increased intraoperative bleeding and increases the risk of postoperative bleeding and complications. However, intraoperative bleeding that interferes with the dissection in the arrested heart is minimal as compared with bleeding in the beating heart; readministration of cardioplegic solution washes out fat debris and red cells that may obscure the dissection field. In the paper by Guiraudon and associates [l], postopera- tive bleeding is compared between two groups of patients undergoing dissection, one on and one off bypass; no difference in blood loss was present at 24 hours. Our group‘s experience with the endocardial technique, as it is 0 1990 by The Society of Thoracic Surgeons Ann Thorac Surg 1990;50:866-7 * 0003-4975/90/$3.50
Transcript
Surgical Treatment of Wolff -Parkinson- White Syndrome T. Bruce Ferguson, Jr, MD Division of Cardiothoracic Surgery, Washington University School of Medicine, St. Louis, Missouri
ince 1984, Guiraudon and associates from London, S Ontario, have advocated an epicardial dissection technique for surgical ablation of accessory pathways responsible for the Wolff-Parkinson-White syndrome. Cardiopulmonary bypass has not been required for acces- sory pathways located in the right free wall and posterior septal regions of the atrioventricular (AV) groove. The fat pad in the AV groove or posterior septal space is dissected off the atrium down to the level of the annulus of the AV valve(s). Cryosurgical lesions are then applied to the annular tissue to ablate any juxtaannular accessory path- ways.
Previously, application of this technique to accessory pathways located in the left free wall space was associated with hemodynamic instability owing to dislocation of the heart out of the pericardial space. In virtually all in- stances, cardiopulmonary bypass was necessary to per- form this dissection, which was begun on the atrial side of the left AV groove and carried down to the level of the mitral annulus. The circumflex coronary artery and coro- nary sinus were thus dissected “en bloc” off the left atrial wall; problems with tearing of the friable left atrial tissue or disruption of the AV groove were occasionally encoun- tered, and concerns about proximity of the circumflex coronary artery to the cryoprobe during freezing have
See also page 968.
been expressed. Finally, even with cardiopulmonary by- pass, exposure can be difficult, particularly in patients with enlarged hearts.
These difficulties have prompted Guiraudon and asso- ciates to alter their dissection technique for left free wall pathways. Their paper in this issue of The Annals entitled “Surgical epicardial ablation of left ventricular pathway using sling exposure” [ 11 describes a method of applying an epicardial dissection technique to pathways located in the left free wall space without the need for cardiopulmo- nary bypass.
To facilitate exposure, the dissection is now performed by dissecting the AV groove fat pad off the ventricle instead of the atrium. This permits better access to the AV groove tissue because the mitral annulus can be ap- proached from above rather than from below (as the heart is dislocated from the pericardium). This epicardial dis- section from the ventricular side of the AV groove was originally reported by Watanabe and associates [2]. A
Address reprint requests to Dr T. Bruce Ferguson, Jr, Su’te 3108 Queeny Tower, Barnes Hospital Plaza, St. Louis, MO 63110.
logical extension of this dissection technique has been to devise a method of exposure to dislocate the heart out of the pericardium that seemingly does not cause hemody- namic compromise, thus obviating the need for cardiopul- monary bypass.
It is important to recognize that both the dissection technique and the exposure technique have been modi- fied; as before, attempts to perform the older “en bloc” resection technique (dissection off the atrial wall) without cardiopulmonary bypass support are not feasible.
The advantages and disadvantages of the more estab- lished endocardial technique versus the “en bloc” or atrial epicardial dissection technique have been discussed for the past 5 years. Initially, the advocates of the epicardial technique stated that this approach led to a lower mor- bidity and mortality than the endocardial approach; in fact, no difference exists between the two techniques when comparable series of patients are analyzed [3, 41. The one study in which the different techniques were performed in the same institution demonstrated no differ- ences in morbidity or mortality between the techniques (51.
The rationale for developing an alternative approach to the classic endocardial dissection technique for ablation of Wolff-Parkinson-White pathways, as stated by Guiraudon and associates [l], is as follows: avoidance of heparin, which results in bleeding during the dissection and in the postoperative period; avoidance of cardiopulmonary by- pass and its associated morbidity; and avoidance of car- dioplegic arrest. Each of these is obviously necessary for dissections on the left side of the heart using the endocar- dial technique.
In the current report [l], unpublished data from their group are referenced to indicate that cardiopulmonary bypass itself is associated with a significant release of the MB fraction of creatine kinase. Although these data sug- gest that cardiopulmonary bypass is associated with myo- cardial damage, they are at odds with the generally accepted concepts regarding bypass. Clearly, hepariniza- tion of the patient produces increased intraoperative bleeding and increases the risk of postoperative bleeding and complications. However, intraoperative bleeding that interferes with the dissection in the arrested heart is minimal as compared with bleeding in the beating heart; readministration of cardioplegic solution washes out fat debris and red cells that may obscure the dissection field. In the paper by Guiraudon and associates [l], postopera- tive bleeding is compared between two groups of patients undergoing dissection, one on and one off bypass; no difference in blood loss was present at 24 hours. Our group‘s experience with the endocardial technique, as it is
0 1990 by The Society of Thoracic Surgeons Ann Thorac Surg 1990;50:866-7 * 0003-4975/90/$3.50
Ann Thorac Surg 1990;50:866-7
EDITORIAL FERGUSON 867 SUKGICAL TREATMENT OF WPW SYNDROME
now performed, is that only 2 of 325 patients have required a return to the operating room for postoperative bleeding. Finally, cardioplegic arrest has the advantage of providing a still and bloodless operative field for the dissection, as opposed to dissection on the beating heart; using current techniques of myocardial preservation, the risk of myocardial injury due either to lack of adequate protection or to the cardioplegic solution itself is ex- tremely small.
The requirement of a bloodless, quiescent operative field to allow complete anatomical dissection was one of the changes made by Cox in 1981 from the original endocardial technique described by Sealy, Iwa, and their associates. These changes were made to achieve a singu- lar goal: to increase the success rate of the initial operative procedure to loo%, thereby reducing the reoperative rate to 0%. Alteration of the operative focus from an electro- physiological one to an anatomical one allowed identical anatomical dissections to be performed for each patient once the anatomical region containing the accessory path- way(s) was defined. To achieve the necessary complete anatomical dissection a quiet, dry operative field is opti- mal. This approach has worked well, even in a patient population in which 20% of patients have multiple acces- sory pathways, an incidence that is significantly higher than other series reported in the literature [4]. The reop- eration rate for the epicardial technique remains approx- imately 3% to 4% in Guiraudon’s series [l, 31.
There are two concerns regarding the techniques de- scribed by Guiraudon and colleagues in their current paper [l]. The first, which will be answered only by long-term follow-up, relates to the fact that the majority of these patients are young and otherwise healthy with normal coronary arteries. To perform the epicardial ”di- rect” dissection described here, it is necessary to skele- tonize the major branches of the circumflex coronary artery as the fat pad is elevated off the top of the ventricular free wall. These marginal branches are epicar- dial vessels, and if they are not separated from the surrounding AV groove fat pad, a substantial recurrence rate of the arrhythmia can be expected because the acces- sory pathways frequently accompany the vascular bun- dles. Because the junction of the epicardial fat pad and the ventricle has to be divided on both sides of the vessel(s) to expose the AV groove and mitral annulus, there may be a long-term risk of fibrosis of the segment of coronary artery that has been stripped of its periadventitial tissue over the length of approximately a centimeter. As with the “en bloc” epicardial technique, concern remains regarding the proximity of the circumflex coronary or its marginal branches to the cryoprobe. It is important to note that with the endocardial approach, which also dissects the AV groove fat pad off the top of the ventricular free wall, the epicardial branches of the circumflex coronary artery remain intact within the epicardial reflection at the com- pletion of the dissection.
The second concern is that the ”sling exposure” tech- nique should only be applied with care, if at all, to older patients undergoing operation for ablation of accessory pathways and to patients with clinically significant ven-
tricular dysfunction. Dislocation of the heart for the 40 to 60 minutes necessary to complete the dissection in this higher-risk population would seem unjustified simply to avoid cardiopulmonary bypass, despite undocumented statements in the paper regarding the lack of effect on systolic and diastolic function induced by the sling expo- sure. Hemodynamic stability is enhanced in all patients undergoing this operative technique by large-volume crystalloid infusion. The 1 patient included in this paper with coronary artery disease had the epicardial technique performed on bypass before revascularization.
The operative morbidity and mortality rates obtained by Guiraudon and associates with this technique are excel- lent. The failure rate remains higher than that reported for the endocardial dissection technique in similar patients, however, and longer follow-up is needed to assure that occult inadvertent injury of the coronary arteries has not occurred.
How, then, does a surgeon decide which approach to use when he or she is just starting to perform operation for the interruption of accessory pathways? In the final analysis, the answer appears to be based on (1) the intraoperative conditions with which that individual sur- geon will be most comfortable and (2) the individual surgeon’s assessment of the balance between the ex- tremely low risks of cardiopulmonary bypass and car- dioplegic arrest as compared with the low but finite risk of initial-operation failure associated with the epicardial dis- section technique. Supraventricular arrhythmia opera- tions have been unique among cardiac procedures in that multiple operations finally resulting in a surgical cure are termed a success.
Regardless of the technique chosen, the results should approach (if not achieve) a 100% initial-operation success rate with an operative mortality in elective uncomplicated cases approaching 0%. These excellent results argue strongly for the consideration of surgical ablation of accessory pathways as the preferred alternative to a lifetime of medical therapy in these predominantly youiig, vtherwise healthy patients.
Cade DM. Surgical epicardial ablation of left ventricular pathway using sling exposure. Ann Thorac Surg 1990;50: 968-71.
2. Watanabe S, Koyanagi H, Endo M, et al. Cryosurgical ablation of accessory atrioventricular pathways without car- diopulmonary bypass: an epicardial approach for the Wolff- Parkinson-White syndrome. Ann Thorac Surg 1989;47 257-64.
3. Guiraudon GM, Klein GJ, Sharma AD, et al. Surgery for the Wolff-Parkinson-White syndrome: the epicardial approach. Semin Thorac Cardiovasc Surg 1989;1:21-33.
4. Cox JL, Ferguson TB Jr. Surgery for the Wolff-Parkinson- White syndrome: the endocardial approach. Semin Thorac Cardiovasc Surg 1989;1:3446.
5. Page PL, Pelletier LC, Kaltenbrunner W, Vitali E, Roy D, Nadeau R. Surgical treatment of the Wolff-Parkinson-White syndrome: endocardial versus epicardial approach. J Thorac Cardiovasc Surg 1990;100:83-7.
