Transra!!wkr STANTON DONALD
b. PERRY, S. BAIM.
of coronary Artery
Closure
MD, JONATHAN
MD.
FACC.
JAMES
ROME. t.
LOCK,
MD.
!OHL
MU.
F KEANE.
MD.
FACC
R,nrnn. ,Wa,wch,,ierr\
Transeathrter closureof a eornnary ar,rr> tistula wasundertaken in nine patients.There were three tirttdas from the left circumlter roronary artery to the euronary sinus,three from the left anterior descendingroro.,ary artery to the right wntricutar apex, tno frcm the right coronary artery b the wperior wna cavairight atria1junrlion and ow L;siutafrum :hc !eft ci~~zn&~ arizr:; :o :he puhtwnsry artery. The tistuta wasctoxd with Gimturco coil5 in six petienits,a doubteanbretta devicein two and a cnr?!,inatinnof
Percutaneous transcatheter implanrarion of cod\ and doubtcumbrella devices hoc been used to claw syrtemic to pubno. nary collateral vesselsand shunts. venous anomalies. patent ductus arteriosus. atrial and ventncular septal defecrr and d variety of other intra- and entracard~ac defects I” pat!ent, :vith cxgeni:s! heart disease (!-5). Tbc use 3f coils (6-101. detachable balloon, (7.8.1 I-IS) and polyvinyl alcohol foam (16.17) to close coronary arteriovenous fiswlas has been reported. We performed cardiac catheterization in I2 patients for possible transcatheter occlusion of a coronary artery fistula and closed the fistula in nine patients by using coi!s or a double-umbrella device, or both.
Methods Study patients (Table I). Between January 1988and July 1991. I2 patients &t two institutions underwent cardiac catheterization for possible transcatheter closure of a coronary artery tistula. The patient’s charts. electrocardiograms IECGs). echoardioerams. catheterization data and cineanpiograms were reviewed. The patients ranged in age from 9 months to 39 years. With the exception of Patient 3, who bad sinu? tachycarda. and Patient 6. who had angina. all were asymptomatic and were taking no medications. A grade 2 to 316 precordial continuous murmur was audible in I of I2 patients. The ECC was normal in all except Patient 6, who had right bundle branch block after repair of tetralogy of Fall@ and
I
w$\ the only patient with associated congenital hear< defeet,. Prccatheteriintion echocardioerdms showed r.ormal ventricular function whom regional~all motion ab,lormaltlw m all .md idenlified the fislulas in 211except Patient 6. who\c two Cstulas weis each 2 mm in diameter. Prrrr rlerion krmodymn~~ dam revealed nwmal atria1 and left ventricular end-diatolic pressures and systemic cardnc output m each pasient. A left to right shunt was detectable by oximetry in eight patients: the largest pulmonary to systemic Row ratio was 2. Test balliwn occlusion of the fictula. which was shown angiographlcally to be complete m all patients. did not change any moniiored variable Iexcept ebminatton of the shunt). loformed wm_wnt. Written informed consem wa? ob tained from the patient or patient’s parents. A protocol for use of double umbrellas to close structures other than patent ductus arteriosus WBEapproved by the Committee on Clinical Inve%tiaationat Children’s Hospital, Boston. Cardiaccatheterization, Routinebrecatheterization sedation was used and uncooperative patients received ketamine or general anesthesia at the time of device placement. Heparin (tu0 Uikg body weight intravenously) was given once vascular access through the femoral anery and vein was obtained. Prophylactic antibiotic agents. usually cefazolin (50 mg/kg to a maximum of I g/dose). were given before device placement and for two doses after catheterizalion. Right and left heart pressures and oxygen saturation were delemuned before closure of the fistula was atteapred. The frnsibility of device clorrrre was based 0’1 definition of the anatomy of the coronary artery fistula and results of test occlusion of the fistula performed with balloon-tipped cathe’e;n. The anatomy of the fistula was defined angiographically. Aortography and selective coronary arlery injections of contrast medium were used 10 determine which coronary branches were involved. In large tiaulas and in
those with high levels of flow, band injections performed with conventional coronary catheters failed to provide adcquate opaciftcation. In lhese cases. power injcclinnr using a Bertnan angiographic catheter were used. In addition. balloon occlusion angiegrams. obtained whh Berman or endhole catheters, were used to define proximal and dtstal anatomy. From these angiagrams. the &&n and number of entry points of the tistula into the heart. the location of normal branches from the involved coronary artery. and the relation cf other structures (e.g., superior vena cava) to the entry sue of the fistula were determined. Tesr occlusion wirh u balloons-ripped carherer was performed for periods of 10 to 25 min. During these occlusions. the ECG, heart rate, mixed venous oxygen saturation and systemic blood pressure were monitored. Transcalheter closure techniques. The coronary artery tistula was &cd by using Cianturco coils (Ocduding Spring Emboli. Cook. Inc.) or a double-umbrella device (Bard PDA Umbrella, Bard Clamshell Septal Umbrella. USC1 Division. C.R. Bard). The techniques for delivenng these devices have been described IS). No device was soaked in topical thrombin. Cuil emholization was performed either retrograde by using the arterial catheter tn = 5) or anterograde through the entry point ofthe tistula into the right side ofthe heart hy using the venous catheter (n = 2). The initial coil was chosen to be 10% to 20% larger than the diameter of the vessel measured when occluded. As with coils. doubleumbrella devices were delivered either anterograde from the femoral vein (n = 2) or retrograde from tbe femoral artery (n = I). Although it is preferable to deliver the umbrella devices from the vein to avoid damaging the artcry, this procedure is not always possible. In Patient 9. for example.
t
Figure1. patient I2 Selective injection into the left eonmary artery demanstr&s three branches that arise from the mid-left anterior descendingewenary artery and enter the right ventricle anteriorly a1 the atrio”e”trrC”tar groove.
the umbrella could not have been delivered from the vein because of the acute angle at the right ventricular apex. Umbrellas were chosen to be at least twice the diameter of the opening into the right side of the heart. Entering the fistula from the right side of the heart is gcnerdlly mnre difficult than entering the fistula from the aorta. In three cases, a catheter was passed from the aorta through the coronary artery. A guide wire was passed through this catheter into the right side of the heart. snared with the venous catheter and pulled out at the fcmorui vein site. This wire was then used to position acatheter for device delivery from the verwus side.
R~SU1t.S Description of the tistulas. Among the I2 Patients, tramcatheter occlusion was not attempted in 3 who had multiple fistulas. Patient 10 had a large fistula involving the right coronary artery with three openings into the right atrium near the superior vent cava-right atrial junction. Patient II had firtulous connections to Ihe nght ventricle from both the distal left anterior descending artery and the left circumflex artery. In cnntrast to the other II patients who had normal coronary artery branching patterns, Patient I2 had ostial atresia of the right cornnary anery. The three tnrtunus branches that arose from the left anterior descending
coronary artery and supplied the fistula (Fig. It also sewed hj cnllateral vessels for the right coronary artery distribuLion. The fistula in eight of the other nme patients had a single opening into the right side of the hean. Wlient 6 had two fistulas. One of these was closed with a coil: in tiie other. which measured 2 mm in diameter. thrombosis occurred during wire and catheter manipulation. The vessels ranged in
diameter from 2 to 17 mm and all had relative stenosis a the site of entry into the right side of the heart. There were three fistulas from the left circumflex coronary artery to the caronary sinus (Fig. 2). three from the left anterior descendingcoronary artery to the right ventricular apex (Fig. 3). two from the right coronary artery to the superior vcna can/right atrial junction (Fig. 4) and one from the left circumflex coronary artery to the pulmonary artery. Coils were used to occlude the fistulas in six patients, a 12-mm Bard PDA umbrella was used in two and a combination of coils and a 12.mm umbrella was used in one patient (Table 2). Postocclusion angiograms demonstrated complete occlusion in xvcn of the nine fisrulas. Of the other two fistulas. one had trivial residual flow at the end of the
1.3 with residual fl&adjacent 10 the umbrella. The fist&a was completely occluded \*ith the use of coils. Andoaraohically. no nor&l coronary artery branches were &luiedby the coils or umbrella in any patient. Meur1J7mroscopy rime x SD wm 97 2 60 min (range 24 ro 2101.The average Ruoroscopy time was I20 min in the first 5 cases ad 73 min in the last five cases. Compwat&m. Of 29 coils placed in seven patients. two migrated to the pulmonary artery. In Patient I, the first coil, placed retrograde from the aorta, migrated to the pulmonary artery and was retrieved. Subsequent coils were delivered anteroaade from the vccous catheter wirhout further QrOb
procedure but complete closure was shoun on a Doppler
echocardiogram obt&cd 24 h after catheterization. Patient 4 had trivial residual Row after imdantation of a 12.mm umbrella (Fig. 41 with no detectable shunt by oximetry and no murmur. However, serial echocardiograms demonstrated a persistent leak and the murmur returned 6 months after
Fiire 3. Fatient 9. A, Balloon occhmionan&gram in the kfi anterior descendingcornnary artery obtainedwith use of an endholecothererdcmonaratestk fistulaopcningintothc right vcmricular apex. Antempartcrior tB, and lateral CC, projections after placementof a 12.mmumb,ellade,,,a,stmtecompleteclosweofthe RStUl@..
IO 14 months) after closure. All ECFs remain normal with no significant changes from preocclusion tracings. By Doppler echocardiography the fistula is completely occluded and ventncularfunction is normal (without regional wall motion ahnormalilies) in all patients.
Discussion terns. In Patient 7. the first coil migrated 10 a small branch of the left lower lobe pulmonary artery. where it was left after unsuccessful attempts IO retrieve it. Ln this p&n!. 0.035.in. (O.OR9.cm) coils were used instead ofthe 0.03&n. (0.097-cm) coils used in other paticnta. In Patient 4, junctional tacbycardia without hemodynamic compromise developed 30 min afler placement of the coils and normal rinus rhythm Rturned I2 h after cathelerizntion. Follow-up. The nine palients undergoing transcalheter fistula closure have been followed up a” awage of 18 months (range I ,043 m,.Ofthese,scvcn have beenfollowed upfor >, year. All nine are asymptomiltic without a mumwr. Each of!he patients has had at least one ECG an average qf 13 months after fistula closure kmge I day to 32 months) and at least one Doppler echocardiogram an average of 6 months (range day
I
Previous studies. In a review of published studies, Liberthson et al. (19) found 174 patients with congenital coronary artery fistulas. Overall, 39% had symptoms or complicalionr including dyspnea on exertion. fatigue, angi- E, congestive heart failure. myocardial infarction, myocardial rupture, subacute bacterial endocarditis and death. Symptomr and complicatianr occurred in 1% of patients ~20 years old and in 63% of those >20 years old. Surgical complicalions occurred more frequently in the latter group. Spontaneous closure of the fistula occurred in only two patients. On the basis of these dam, the authors (19) recommended closure of coronary artery hstulas during childhood even in asymptomatic patients Several recent reports have demonstrated the feasibility of transcatheter clowre of coronary art&venous tistulas. Reidy et al. @I recently followed up earlier case reports (6.7) with a report of successful occlusion of a coronary arteriovenous tistula with coils or detachable balloons. or both, in six of seven patients. The only significant complication in their series was a single episode of deflation and migrarion of a detachable balloon that was nol associated with clinical sequelae other than failure to occlude that fistula. Other published data. all case reports, have described u6e of coils (9,101. detachable balloons (I I-151 or polytieyl foam (16.17) to close a congenital or iatrogenic coronary artery fistula. With the exception of one procedure, in which a balloon migrated and needed to be retrieved (12). 811these closures were successful. F?‘esenttechniques and results. We report successful closure of nine coronary artery tir~ulas with either coils or a double umbrella. The choice of these devices is somewhat arbitrary in most patients. Coils cost less than an umbrella, can be delivered through a very small catheter (3F) and.
because they are positioned entirely within tbc firlula. intcrference with other structures IS not a rn*:~r wncern. Currently available 12.mm umbrellas require at least a 7F sheath and larger umbrellas require an sheath. However. coils. particularly when several of them are required. generally occupy a greater volume or length of the vwcl than do umbrellas. Thus. large fistida ur thrac with brancnrs ~~izr the end, may be more appmpriaray clowd with an umbrella. Although we did not use detachable balloons in any case. these may have a significant advantage in an occnional patient by virtue of their ability to follow lortuous catheter cou~scs. Thus. familiariry with alI three ~~~l~swe technique? may be required for optimal success. Fistulas with multiple openings rcprcsent a more difficult problem than do those with rinele aoenines. Altboueh we du.I not atlempt closure of three listulas with multiple opening
b. PERRY, S. BAIM.
of coronary Artery
Closure
MD, JONATHAN
MD.
FACC.
JAMES
ROME. t.
LOCK,
MD.
!OHL
MU.
F KEANE.
MD.
FACC
R,nrnn. ,Wa,wch,,ierr\
Transeathrter closureof a eornnary ar,rr> tistula wasundertaken in nine patients.There were three tirttdas from the left circumlter roronary artery to the euronary sinus,three from the left anterior descendingroro.,ary artery to the right wntricutar apex, tno frcm the right coronary artery b the wperior wna cavairight atria1junrlion and ow L;siutafrum :hc !eft ci~~zn&~ arizr:; :o :he puhtwnsry artery. The tistuta wasctoxd with Gimturco coil5 in six petienits,a doubteanbretta devicein two and a cnr?!,inatinnof
Percutaneous transcatheter implanrarion of cod\ and doubtcumbrella devices hoc been used to claw syrtemic to pubno. nary collateral vesselsand shunts. venous anomalies. patent ductus arteriosus. atrial and ventncular septal defecrr and d variety of other intra- and entracard~ac defects I” pat!ent, :vith cxgeni:s! heart disease (!-5). Tbc use 3f coils (6-101. detachable balloon, (7.8.1 I-IS) and polyvinyl alcohol foam (16.17) to close coronary arteriovenous fiswlas has been reported. We performed cardiac catheterization in I2 patients for possible transcatheter occlusion of a coronary artery fistula and closed the fistula in nine patients by using coi!s or a double-umbrella device, or both.
Methods Study patients (Table I). Between January 1988and July 1991. I2 patients &t two institutions underwent cardiac catheterization for possible transcatheter closure of a coronary artery tistula. The patient’s charts. electrocardiograms IECGs). echoardioerams. catheterization data and cineanpiograms were reviewed. The patients ranged in age from 9 months to 39 years. With the exception of Patient 3, who bad sinu? tachycarda. and Patient 6. who had angina. all were asymptomatic and were taking no medications. A grade 2 to 316 precordial continuous murmur was audible in I of I2 patients. The ECC was normal in all except Patient 6, who had right bundle branch block after repair of tetralogy of Fall@ and
I
w$\ the only patient with associated congenital hear< defeet,. Prccatheteriintion echocardioerdms showed r.ormal ventricular function whom regional~all motion ab,lormaltlw m all .md idenlified the fislulas in 211except Patient 6. who\c two Cstulas weis each 2 mm in diameter. Prrrr rlerion krmodymn~~ dam revealed nwmal atria1 and left ventricular end-diatolic pressures and systemic cardnc output m each pasient. A left to right shunt was detectable by oximetry in eight patients: the largest pulmonary to systemic Row ratio was 2. Test balliwn occlusion of the fictula. which was shown angiographlcally to be complete m all patients. did not change any moniiored variable Iexcept ebminatton of the shunt). loformed wm_wnt. Written informed consem wa? ob tained from the patient or patient’s parents. A protocol for use of double umbrellas to close structures other than patent ductus arteriosus WBEapproved by the Committee on Clinical Inve%tiaationat Children’s Hospital, Boston. Cardiaccatheterization, Routinebrecatheterization sedation was used and uncooperative patients received ketamine or general anesthesia at the time of device placement. Heparin (tu0 Uikg body weight intravenously) was given once vascular access through the femoral anery and vein was obtained. Prophylactic antibiotic agents. usually cefazolin (50 mg/kg to a maximum of I g/dose). were given before device placement and for two doses after catheterizalion. Right and left heart pressures and oxygen saturation were delemuned before closure of the fistula was atteapred. The frnsibility of device clorrrre was based 0’1 definition of the anatomy of the coronary artery fistula and results of test occlusion of the fistula performed with balloon-tipped cathe’e;n. The anatomy of the fistula was defined angiographically. Aortography and selective coronary arlery injections of contrast medium were used 10 determine which coronary branches were involved. In large tiaulas and in
those with high levels of flow, band injections performed with conventional coronary catheters failed to provide adcquate opaciftcation. In lhese cases. power injcclinnr using a Bertnan angiographic catheter were used. In addition. balloon occlusion angiegrams. obtained whh Berman or endhole catheters, were used to define proximal and dtstal anatomy. From these angiagrams. the &&n and number of entry points of the tistula into the heart. the location of normal branches from the involved coronary artery. and the relation cf other structures (e.g., superior vena cava) to the entry sue of the fistula were determined. Tesr occlusion wirh u balloons-ripped carherer was performed for periods of 10 to 25 min. During these occlusions. the ECG, heart rate, mixed venous oxygen saturation and systemic blood pressure were monitored. Transcalheter closure techniques. The coronary artery tistula was &cd by using Cianturco coils (Ocduding Spring Emboli. Cook. Inc.) or a double-umbrella device (Bard PDA Umbrella, Bard Clamshell Septal Umbrella. USC1 Division. C.R. Bard). The techniques for delivenng these devices have been described IS). No device was soaked in topical thrombin. Cuil emholization was performed either retrograde by using the arterial catheter tn = 5) or anterograde through the entry point ofthe tistula into the right side ofthe heart hy using the venous catheter (n = 2). The initial coil was chosen to be 10% to 20% larger than the diameter of the vessel measured when occluded. As with coils. doubleumbrella devices were delivered either anterograde from the femoral vein (n = 2) or retrograde from tbe femoral artery (n = I). Although it is preferable to deliver the umbrella devices from the vein to avoid damaging the artcry, this procedure is not always possible. In Patient 9. for example.
t
Figure1. patient I2 Selective injection into the left eonmary artery demanstr&s three branches that arise from the mid-left anterior descendingewenary artery and enter the right ventricle anteriorly a1 the atrio”e”trrC”tar groove.
the umbrella could not have been delivered from the vein because of the acute angle at the right ventricular apex. Umbrellas were chosen to be at least twice the diameter of the opening into the right side of the heart. Entering the fistula from the right side of the heart is gcnerdlly mnre difficult than entering the fistula from the aorta. In three cases, a catheter was passed from the aorta through the coronary artery. A guide wire was passed through this catheter into the right side of the heart. snared with the venous catheter and pulled out at the fcmorui vein site. This wire was then used to position acatheter for device delivery from the verwus side.
R~SU1t.S Description of the tistulas. Among the I2 Patients, tramcatheter occlusion was not attempted in 3 who had multiple fistulas. Patient 10 had a large fistula involving the right coronary artery with three openings into the right atrium near the superior vent cava-right atrial junction. Patient II had firtulous connections to Ihe nght ventricle from both the distal left anterior descending artery and the left circumflex artery. In cnntrast to the other II patients who had normal coronary artery branching patterns, Patient I2 had ostial atresia of the right cornnary anery. The three tnrtunus branches that arose from the left anterior descending
coronary artery and supplied the fistula (Fig. It also sewed hj cnllateral vessels for the right coronary artery distribuLion. The fistula in eight of the other nme patients had a single opening into the right side of the hean. Wlient 6 had two fistulas. One of these was closed with a coil: in tiie other. which measured 2 mm in diameter. thrombosis occurred during wire and catheter manipulation. The vessels ranged in
diameter from 2 to 17 mm and all had relative stenosis a the site of entry into the right side of the heart. There were three fistulas from the left circumflex coronary artery to the caronary sinus (Fig. 2). three from the left anterior descendingcoronary artery to the right ventricular apex (Fig. 3). two from the right coronary artery to the superior vcna can/right atrial junction (Fig. 4) and one from the left circumflex coronary artery to the pulmonary artery. Coils were used to occlude the fistulas in six patients, a 12-mm Bard PDA umbrella was used in two and a combination of coils and a 12.mm umbrella was used in one patient (Table 2). Postocclusion angiograms demonstrated complete occlusion in xvcn of the nine fisrulas. Of the other two fistulas. one had trivial residual flow at the end of the
1.3 with residual fl&adjacent 10 the umbrella. The fist&a was completely occluded \*ith the use of coils. Andoaraohically. no nor&l coronary artery branches were &luiedby the coils or umbrella in any patient. Meur1J7mroscopy rime x SD wm 97 2 60 min (range 24 ro 2101.The average Ruoroscopy time was I20 min in the first 5 cases ad 73 min in the last five cases. Compwat&m. Of 29 coils placed in seven patients. two migrated to the pulmonary artery. In Patient I, the first coil, placed retrograde from the aorta, migrated to the pulmonary artery and was retrieved. Subsequent coils were delivered anteroaade from the vccous catheter wirhout further QrOb
procedure but complete closure was shoun on a Doppler
echocardiogram obt&cd 24 h after catheterization. Patient 4 had trivial residual Row after imdantation of a 12.mm umbrella (Fig. 41 with no detectable shunt by oximetry and no murmur. However, serial echocardiograms demonstrated a persistent leak and the murmur returned 6 months after
Fiire 3. Fatient 9. A, Balloon occhmionan&gram in the kfi anterior descendingcornnary artery obtainedwith use of an endholecothererdcmonaratestk fistulaopcningintothc right vcmricular apex. Antempartcrior tB, and lateral CC, projections after placementof a 12.mmumb,ellade,,,a,stmtecompleteclosweofthe RStUl@..
IO 14 months) after closure. All ECFs remain normal with no significant changes from preocclusion tracings. By Doppler echocardiography the fistula is completely occluded and ventncularfunction is normal (without regional wall motion ahnormalilies) in all patients.
Discussion terns. In Patient 7. the first coil migrated 10 a small branch of the left lower lobe pulmonary artery. where it was left after unsuccessful attempts IO retrieve it. Ln this p&n!. 0.035.in. (O.OR9.cm) coils were used instead ofthe 0.03&n. (0.097-cm) coils used in other paticnta. In Patient 4, junctional tacbycardia without hemodynamic compromise developed 30 min afler placement of the coils and normal rinus rhythm Rturned I2 h after cathelerizntion. Follow-up. The nine palients undergoing transcalheter fistula closure have been followed up a” awage of 18 months (range I ,043 m,.Ofthese,scvcn have beenfollowed upfor >, year. All nine are asymptomiltic without a mumwr. Each of!he patients has had at least one ECG an average qf 13 months after fistula closure kmge I day to 32 months) and at least one Doppler echocardiogram an average of 6 months (range day
I
Previous studies. In a review of published studies, Liberthson et al. (19) found 174 patients with congenital coronary artery fistulas. Overall, 39% had symptoms or complicalionr including dyspnea on exertion. fatigue, angi- E, congestive heart failure. myocardial infarction, myocardial rupture, subacute bacterial endocarditis and death. Symptomr and complicatianr occurred in 1% of patients ~20 years old and in 63% of those >20 years old. Surgical complicalions occurred more frequently in the latter group. Spontaneous closure of the fistula occurred in only two patients. On the basis of these dam, the authors (19) recommended closure of coronary artery hstulas during childhood even in asymptomatic patients Several recent reports have demonstrated the feasibility of transcatheter clowre of coronary art&venous tistulas. Reidy et al. @I recently followed up earlier case reports (6.7) with a report of successful occlusion of a coronary arteriovenous tistula with coils or detachable balloons. or both, in six of seven patients. The only significant complication in their series was a single episode of deflation and migrarion of a detachable balloon that was nol associated with clinical sequelae other than failure to occlude that fistula. Other published data. all case reports, have described u6e of coils (9,101. detachable balloons (I I-151 or polytieyl foam (16.17) to close a congenital or iatrogenic coronary artery fistula. With the exception of one procedure, in which a balloon migrated and needed to be retrieved (12). 811these closures were successful. F?‘esenttechniques and results. We report successful closure of nine coronary artery tir~ulas with either coils or a double umbrella. The choice of these devices is somewhat arbitrary in most patients. Coils cost less than an umbrella, can be delivered through a very small catheter (3F) and.
because they are positioned entirely within tbc firlula. intcrference with other structures IS not a rn*:~r wncern. Currently available 12.mm umbrellas require at least a 7F sheath and larger umbrellas require an sheath. However. coils. particularly when several of them are required. generally occupy a greater volume or length of the vwcl than do umbrellas. Thus. large fistida ur thrac with brancnrs ~~izr the end, may be more appmpriaray clowd with an umbrella. Although we did not use detachable balloons in any case. these may have a significant advantage in an occnional patient by virtue of their ability to follow lortuous catheter cou~scs. Thus. familiariry with alI three ~~~l~swe technique? may be required for optimal success. Fistulas with multiple openings rcprcsent a more difficult problem than do those with rinele aoenines. Altboueh we du.I not atlempt closure of three listulas with multiple opening
