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Page 8 of 11                                               Depboylu et al. Vessel Plus 2018;2:26  I  http://dx.doi.org/10.20517/2574-1209.2018.39

               equal to or more than 3 g/dL and the ones those require 2-3 units of red blood cells transfusion can be de-
               fined as major bleeding.


               Minor bleeding
               All bleedings other than life-threatening and major bleedings can be described as minor bleeding.


               Cardiac tamponade due to bleeding to the pericardium is seen in about 3%-4% of the patients who under-
                                                       [35]
               went TAVR and causes high rate of death (24%) . Of the access-site complications, 69% is bleeding and 23%-
               31% of them are life-threatening ones. Digestive tract, the retro-peritoneum, and the pleura may be listed as
               the other sources of bleedings.

               In case of such complications, the anticoagulation should be reversed and if needed transfusion of fresh
               frozen plasma and/or red blood cells should be performed. Hemodynamic conditions and hemoglobin levels
               should be stabilized. If feasible, the source of the bleeding should be treated surgically.



               CARDIAC CONDUCTION ABNORMALITIES
               Conduction system damages are one of the major complications of TAVR and can be listed as: (1) prolonged
               atrio-ventricular (AV) conduction time; (2) AV block; (3) left bundle branch block; and (4) need for perma-
               nent pacemaker implantation.


               The thickness of the ventricular septum, thickness of the non-coronary aortic cusp, implantation depth of
               the prosthetic valve in the left ventricular outflow tract, post implantation dilatation of the prosthetic valve,
               type of prosthetic valve and pre-existence of right bundle branch block can be listed as the risk factors for
               occurrence of conduction abnormalities [36,37] . The incidence of conduction abnormalities after TAVR varies
                                [38]
               between 5.7%-42.5% . The incidence of AV block varies between 24.5%-25.8% for CoreValve® and 5.9%-6.5%
                                       [39]
               for Edwards SAPIEN® valve . Besides the prosthetic valve, manipulation of the guide wires and catheter
               systems in the left ventricular outflow tract may also cause temporary or permanent conduction system
               injuries. Most of the conduction abnormalities occur during the procedure (after the isolated aortic balloon
                                                                        [40]
               valvuloplasty and before the implantation of the prosthetic valve) . New left bundle branch block is the
               most seen conduction abnormality with the rate of 25%-85% for CoreValve® and 8%-30% for Edwards SA-
                         [41]
               PIEN® valve . The risk of AV block is higher for CoreValve® due to its self-expandable design and the pos-
               sible deeper implantation into the left ventricular outflow tract. For preventing the complications related to
               conduction pathways, patients should be carefully screened for risk factors.

               In case of such complications, trans-venous pacemaker implantation with conversion to permanent pace-
                                                     [14]
               maker is the most common treatment option .

               ACUTE RENAL INJURY
               The incidence of acute renal injuries after TAVR is about 22% and less than half of them are acute renal
                                             [42]
               injuries in stage 2 or stage 3 (8.4%) . The predisposing factors for acute renal injuries can be listed as: (1)
               chronic renal disease; (2) peripheral vascular disease; (3) diabetes mellitus; (4) hypoperfusion during rapid
               ventricular pacing; and (5) aortic plaque embolism in the renal arteries.

               In case of any renal complication, the cessation of nephrotoxic drugs and the start of hydration procedure
               should be performed. If needed hemodialysis may be the treatment option.


               DEATH
               The mortality incidence after TAVR varies between 5%-10%. No significant difference about mortality has
                                                                                                  [2,8]
               been reported between the self-expandable and balloon expandable prosthetic valve implantation . How-
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