iatrogenic aortocoronary dissection is a rare but potentially disastrous complication of percutaneous coronary intervention ( pci ) . this is one of the important causes for procedure failure associated with the risk of myocardial infarction and death , where the incidence has been reported about 0.1% in previous studies . the rapid development of antegrade and/or retrograde dissection flap not only causes acute closure of the coronary artery , but also brings about aortic regurgitation , haemopericardium or even abdominal aorta dissection in severe cases . , the left main ( lm ) dissection extending into distal bifurcation involving both the left anterior descending ( lad ) and left circumflex ( lcx ) is a complex and vital complication , which is classified as eshtehardi type ii dissection . we presented a case of iatrogenic lm dissection with upcoming closure of both major branches , which was successfully managed by immediate bail - out tap - stenting ( t - stenting and small protrusion technique ) . a 77-year - old female had been suffering from ischemia - related chest pain for 6 years . transradial coronary angiography revealed severe lesions in proximal lad and mid lcx ( figure 1a , 1b ) . there was no critical stenosis in the lm and right coronary artery . a sirolimus - eluting stent ( 2.5/28 mm , cypherselect , cordis ) was successfully implanted in lcx . when performed pre - dilation in mid lad by semi - compliant balloon ( 2.5/15 mm , voyager , abbott ) , a retrograde dissection extended from mid lad to lm and aorta ( figure 1c , white arrows ) . despite obliteration of the lm - lad dissection with two stents ( 2.75/33 mm in lad , 3.5/33 mm in lm , cypherselect , cordis ) , retrograde extension of lcx dissection was present on subsequent angiographic view ( figure 1d , white arrow ) . thereafter , we performed tap - stenting in the lm bifurcation ( 2.75/33 mm in lcx , cypherselect , cordis ) by transradial approach ( figure 1e , 1f ) . the patient was discharged without any complication , and 1-year follow - up indicated stent patency and favorable clinical result ( figure 1 g , 1h ) . although emergency surgical repair is generally the first - choice therapeutic strategy , when taking full anticoagulation and antiplatelet settings into consideration , as well as the unstable hemodynamic condition , surgery may be more risky in this circumstance . actually , sealing the entry site of dissection immediately by stent prevents the rapid development of hematoma . ( a&b ) : transradial coronary angiography revealed severe lesions in proximal lad and mid lcx . ( c ) : a sirolimus - eluting stent ( 2.5/28 mm , cypherselect , cordis ) was successfully implanted in lcx . when we performed pre - dilation in mid lad by semi - compliant balloon ( 2.5/15 mm , voyager , abbott ) , a retrograde dissection extended from mid lad to lm and aorta ( white arrow ) . ( d ) : despite obliteration of the lm - lad dissection with two stents ( 2.75/33 mm in lad , 3.5/33 mm in lm , cypherselect , cordis ) , retrograde extension of lcx dissection was present on subsequent angiographic view ( white arrow ) . ( e&f ) : we performed tap - stenting ( t - stenting and small protrusion technique ) in the lm bifurcation by transradial approach ( 2.75/33 mm in lcx , cypherselect , cordis ) . ( g&h ) : the 77-year - old patient was discharged without any complication , and 1-year follow - up indicated stent patency and favorable clinical result . lad : left anterior descending ; lcx : left circumflex ; lm : left main . some lessons from this case include : ( 1 ) it is crucial to maintain entire system stability to manage the complication based on the initial guiding catheter and wire . if the operator decides to change access ( radial to femoral ) , or the size of guiding catheter ( 6f to 7f or even 8f ) , the guide wire will cross the dissection again . it is imaginable that the guide wire may enter a false lumen so as to prolong the operation time , and than dissection deteriorates . ( 2 ) since the most important vessel should be kept patent first , single - stent strategy is the first - choice when taking 6f transradial access into account . under emergency of lm bifurcation dissection , the operator should choose a simple stenting technique to reduce difficulty and complexity of management . actually , it is difficult to thread the stent strut under emergency conditions , so bifurcation stenting can be left for senior operator . ( 3 ) only if procedure could be finished in short order and then the risk would be reduced . try to identify and seal the entry port with a long stent at once , and stop blood flow in the false lumen to avoid the distribution of dissection before hemodynamic collapse . while blood flow is still poor after stenting , consider intravascular ultrasound to determine whether the stent covers entry port , and whether flow limitation is due to thrombus or intramural hematoma , in order to manage more or less aggressive anticoagulation . moreover , we should keep in mind that circulatory support is not mandatory or even contraindicated . it is the fact that the extension of dissection and hematoma lead to acute closure of vessel . theoretically , even if hemodynamic collapse occurred , intra - aortic balloon pump should not be implanted because it can only delay stent deployment , and exacerbate both of the antegrade and retrograde dissection . ( 4 ) the operator should save the patient by himself , and hardly count on surgeons . when coronary sinus dissection is detected , deployment of an additional stent that protruded into the aorta helps to prevent acute artery occlusion due to torn flap of aorta . if bifurcation stenting is unavoidable , the tap - stenting technique is relatively simple , which is proved to allow full coverage of bifurcation lesions and facilitate final kissing balloon . this report presented a case of iatrogenic lm bifurcation dissection with upcoming closure of lad and lcx , which was successfully managed by immediate bail - out tap - stenting . from the above , we introduce the  4s  law for treatment in this report , which is  stable , smart , swift and stent  . the  4s  law based on immediate bail - out stenting is a feasible and reasonable initial management for this lethal complication .
iatrogenic aortocoronary dissection is a rare but potentially disastrous complication of percutaneous coronary intervention . 
 the left main dissection extending into distal bifurcation involving both the left anterior descending and left circumflex is a complex and vital complication , which is classified as eshtehardi type ii dissection . 
 we presented a case of iatrogenic left main coronary artery dissection with upcoming closure of both major branches , which was successfully managed by immediate bail - out tap - stenting . 
 the 77-year - old patient was discharged without any complication , and 1-year follow - up indicated stent patency and favorable clinical result . 
 immediate bail - out stenting is a feasible and reasonable initial management for this lethal complication .