Cardiac and Extracardiac Complications During CTO Interventions
Cardiac and Extracardiac Complications During CTO Interventions
In a retrospective study addressing iatrogenic aortic dissection during heart catheterization, treatment of CTO was a factor related to the onset of such a complication. Dissection of the ascending aorta could be the result of guide catheter trauma, forceful contrast injection with a 'wedged' guiding catheter or retrograde propagation of dissection from the proximal or ostial segment of the coronary artery. Recanalization of CTO of the right coronary artery is the most frequent scenario for this complication (Figure 8). Dissection may be limited to the coronary sinus, may extend to the proximal ascending aorta or, in the worst scenario, could extend beyond the ascending aorta (Table 3). Predisposing factors are deep coronary engagement and the utilization of aggressive guiding catheters, such as 8 Fr Amplatz catheters (Figure 8). It has been suggested that the use of guiding catheters with side holes could limit the incidence of this severe complication. In the case of dissection limited to the coronary sinus or proximal ascending aorta, the suggested conservative management consists of anticoagulation reversion, heart rate and blood pressure control and close monitoring of the progression of the dissection with computed tomography or transesophageal echocardiography. When the etiologic mechanism relies on retrograde propagation of a dissection originating from the proximal coronary artery segment, implantation of a stent at the coronary ostium could limit further dissection expansion. In case of dissection extending over the ascending aorta or it being complicated by aortic regurgitation or pericardial effusion, management consists of emergent surgery (Figure 8).
(Enlarge Image)
Figure 8.
Type A aortic dissection complicating an attempt of chronic total occlusion recanalization.
(A) Baseline coronary angiography showing the chronic total occlusion of the proximal right coronary artery. (B) The mid and distal right coronary artery was well visualized during left coronary artery angiography by means of contralateral collaterals. (A & B) An 8-Fr, Amplatz-shaped guiding catheter was used for the antegrade attempt of recanalization (arrows). (C & D) During the procedure, the patient complained of chest pain, and supravalvular aortography showed aortic dissection extending from the right coronary sinus to the ascending aorta (type 3 of Dunning). Emergent surgery was performed. The mechanism of the aortic dissection was probably related to traumatic effect of the aggressive 8-Fr Amplatz catheter.
Angioplasty of CTO entails a significant risk of contrast-induced nephropathy mainly because the long procedure requires large contrast volume, and often a second (or third) attempt is needed for successful recanalization. As for non-CTO PCI, in each patient undergoing a CTO procedure, the risk for contrast-induced nephropathy must be preliminarily estimated according to a validated score and all the available prophylactic modalities must be adopted, keeping in mind that it is probable that the first line of prevention consists of a strict limitation of contrast amount and avoidance of repeated use of contrast within a short period of time (Box 1).
Radiation skin injury could be a deterministic, dose-dependent complication of CTO procedure. Transient erythema, permanent epilation and delayed dermal necrosis can occur at 2, 7 and 12 Gy, respectively. It has been demonstrated that total fluoroscopy time, total number of cine frames and entrance skin dose are greater in CTO than in non-CTO interventions. Furthermore, although the initial success of CTO intervention has become higher than in the past, on average, a quarter of procedures fail and repeat intervention may needed. In addition, even with the utilization of DES, the restenosis rate is not negligible. Therefore, reducing both the patient's skin dose during each procedure, as well as the cumulative dose in the same area of skin during repeat procedure, should be pursued. Several methods allow for the reduction of the patient's maximum skin dose during CTO procedures. Utilization of latest generation equipment with extra beam filtering and extrashielded x-ray tubes, together with the use of pulsed fluoroscopy and choice of low-dose settings, should be considered mandatory for CTO procedures. Furthermore, for angiographic documentation, rather than the digital cine mode storage, the pulsed fluoroscopy mode could be used (reducing radiation exposure by a factor of four). In addition, altering the beam angulation by rotating the x-ray tube more than 40° may reduce the patient's skin radiation dose. Radiation monitoring is important; therefore, a detailed record of the exact radiation exposure in every patient should be kept. When the cumulative dose in the same area of the skin is so high as to be associated with risk of injury, dermatological follow-up should be scheduled.
Despite the utilization of 7 or 8 Fr sheaths and bilateral approach, available data suggest that the incidence of vascular complication related to CTO intervention is similar to that for non-CTO intervention. A useful strategy to limit vascular complication could be the use of the radial approach or the utilization of a 4 Fr diagnostic catheter from the femoral access to perform the angiography of the donor artery. The rate of cerebrovascular complication during CTO procedures is the same as for other types of PCIs.
Extracardiac Complications
Aortic Dissection
In a retrospective study addressing iatrogenic aortic dissection during heart catheterization, treatment of CTO was a factor related to the onset of such a complication. Dissection of the ascending aorta could be the result of guide catheter trauma, forceful contrast injection with a 'wedged' guiding catheter or retrograde propagation of dissection from the proximal or ostial segment of the coronary artery. Recanalization of CTO of the right coronary artery is the most frequent scenario for this complication (Figure 8). Dissection may be limited to the coronary sinus, may extend to the proximal ascending aorta or, in the worst scenario, could extend beyond the ascending aorta (Table 3). Predisposing factors are deep coronary engagement and the utilization of aggressive guiding catheters, such as 8 Fr Amplatz catheters (Figure 8). It has been suggested that the use of guiding catheters with side holes could limit the incidence of this severe complication. In the case of dissection limited to the coronary sinus or proximal ascending aorta, the suggested conservative management consists of anticoagulation reversion, heart rate and blood pressure control and close monitoring of the progression of the dissection with computed tomography or transesophageal echocardiography. When the etiologic mechanism relies on retrograde propagation of a dissection originating from the proximal coronary artery segment, implantation of a stent at the coronary ostium could limit further dissection expansion. In case of dissection extending over the ascending aorta or it being complicated by aortic regurgitation or pericardial effusion, management consists of emergent surgery (Figure 8).
(Enlarge Image)
Figure 8.
Type A aortic dissection complicating an attempt of chronic total occlusion recanalization.
(A) Baseline coronary angiography showing the chronic total occlusion of the proximal right coronary artery. (B) The mid and distal right coronary artery was well visualized during left coronary artery angiography by means of contralateral collaterals. (A & B) An 8-Fr, Amplatz-shaped guiding catheter was used for the antegrade attempt of recanalization (arrows). (C & D) During the procedure, the patient complained of chest pain, and supravalvular aortography showed aortic dissection extending from the right coronary sinus to the ascending aorta (type 3 of Dunning). Emergent surgery was performed. The mechanism of the aortic dissection was probably related to traumatic effect of the aggressive 8-Fr Amplatz catheter.
Contrast-induced Nephropathy
Angioplasty of CTO entails a significant risk of contrast-induced nephropathy mainly because the long procedure requires large contrast volume, and often a second (or third) attempt is needed for successful recanalization. As for non-CTO PCI, in each patient undergoing a CTO procedure, the risk for contrast-induced nephropathy must be preliminarily estimated according to a validated score and all the available prophylactic modalities must be adopted, keeping in mind that it is probable that the first line of prevention consists of a strict limitation of contrast amount and avoidance of repeated use of contrast within a short period of time (Box 1).
Radiation Injury
Radiation skin injury could be a deterministic, dose-dependent complication of CTO procedure. Transient erythema, permanent epilation and delayed dermal necrosis can occur at 2, 7 and 12 Gy, respectively. It has been demonstrated that total fluoroscopy time, total number of cine frames and entrance skin dose are greater in CTO than in non-CTO interventions. Furthermore, although the initial success of CTO intervention has become higher than in the past, on average, a quarter of procedures fail and repeat intervention may needed. In addition, even with the utilization of DES, the restenosis rate is not negligible. Therefore, reducing both the patient's skin dose during each procedure, as well as the cumulative dose in the same area of skin during repeat procedure, should be pursued. Several methods allow for the reduction of the patient's maximum skin dose during CTO procedures. Utilization of latest generation equipment with extra beam filtering and extrashielded x-ray tubes, together with the use of pulsed fluoroscopy and choice of low-dose settings, should be considered mandatory for CTO procedures. Furthermore, for angiographic documentation, rather than the digital cine mode storage, the pulsed fluoroscopy mode could be used (reducing radiation exposure by a factor of four). In addition, altering the beam angulation by rotating the x-ray tube more than 40° may reduce the patient's skin radiation dose. Radiation monitoring is important; therefore, a detailed record of the exact radiation exposure in every patient should be kept. When the cumulative dose in the same area of the skin is so high as to be associated with risk of injury, dermatological follow-up should be scheduled.
Other Complications
Despite the utilization of 7 or 8 Fr sheaths and bilateral approach, available data suggest that the incidence of vascular complication related to CTO intervention is similar to that for non-CTO intervention. A useful strategy to limit vascular complication could be the use of the radial approach or the utilization of a 4 Fr diagnostic catheter from the femoral access to perform the angiography of the donor artery. The rate of cerebrovascular complication during CTO procedures is the same as for other types of PCIs.
